packages feed

JuicyPixels 3.2.9.5 → 3.3.9

raw patch · 46 files changed

Files

JuicyPixels.cabal view
@@ -1,5 +1,5 @@ Name:                JuicyPixels
-Version:             3.2.9.5
+Version:             3.3.9
 Synopsis:            Picture loading/serialization (in png, jpeg, bitmap, gif, tga, tiff and radiance)
 Description:
     <<data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAMAAAADABAMAAACg8nE0AAAAElBMVEUAAABJqDSTWEL/qyb///8AAABH/1GTAAAAAXRSTlMAQObYZgAAAN5JREFUeF7s1sEJgFAQxFBbsAV72v5bEVYWPwT/XDxmCsi7zvHXavYREBDI3XP2GgICqBBYuwIC+/rVayPUAyAg0HvIXBcQoDFDGnUBgWQQ2Bx3AYFaRoBpAQHWb3bt2ARgGAiCYFFuwf3X5HA/McgGJWI2FdykCv4aBYzmKwDwvl6NVmUAAK2vlwEALK7fo88GANB6HQsAAAAAAAAA7P94AQCzswEAAAAAAAAAAAAAAAAAAICzh4UAO4zWAYBfRutHA4Bn5C69JhowAMGoBaMWDG0wCkbBKBgFo2AUAACPmegUST/IJAAAAABJRU5ErkJggg==>>
@@ -14,11 +14,21 @@ Category:            Codec, Graphics, Image
 Stability:           Stable
 Build-type:          Simple
-
--- Constraint on the version of Cabal needed to build this package.
-Cabal-version:       >= 1.18
+cabal-version: 1.18
+tested-with:
+  GHC == 9.8.1
+  GHC == 9.6.4
+  GHC == 9.4.8
+  GHC == 9.2.8
+  GHC == 9.0.2
+  GHC == 8.10.7
+  GHC == 8.8.4
+  GHC == 8.6.5
+  GHC == 8.4.4
+  GHC == 8.2.2
+  GHC == 8.0.2
 
-extra-source-files: changelog, docimages/*.png, docimages/*.svg, README.md
+extra-doc-files: changelog, docimages/*.png, docimages/*.svg, README.md
 extra-doc-files: docimages/*.png, docimages/*.svg
 
 Source-Repository head
@@ -28,7 +38,7 @@ Source-Repository this
     Type:      git
     Location:  git://github.com/Twinside/Juicy.Pixels.git
-    Tag:       v3.2.9.5
+    Tag:       v3.3.8
 
 Flag Mmap
     Description: Enable the file loading via mmap (memory map)
@@ -37,6 +47,7 @@ Library
   hs-source-dirs: src
   Default-Language: Haskell2010
+  default-extensions: TypeOperators
   Exposed-modules:  Codec.Picture,
                     Codec.Picture.Bitmap,
                     Codec.Picture.Gif,
@@ -49,40 +60,36 @@                     Codec.Picture.Metadata.Exif,
                     Codec.Picture.Saving,
                     Codec.Picture.Types,
-                    Codec.Picture.ColorQuant
+                    Codec.Picture.ColorQuant,
+                    Codec.Picture.Jpg.Internal.DefaultTable,
+                    Codec.Picture.Jpg.Internal.Metadata,
+                    Codec.Picture.Jpg.Internal.FastIdct,
+                    Codec.Picture.Jpg.Internal.FastDct,
+                    Codec.Picture.Jpg.Internal.Types,
+                    Codec.Picture.Jpg.Internal.Common,
+                    Codec.Picture.Jpg.Internal.Progressive,
+                    Codec.Picture.Gif.Internal.LZW,
+                    Codec.Picture.Gif.Internal.LZWEncoding,
+                    Codec.Picture.Png.Internal.Export,
+                    Codec.Picture.Png.Internal.Type,
+                    Codec.Picture.Png.Internal.Metadata,
+                    Codec.Picture.Tiff.Internal.Metadata,
+                    Codec.Picture.Tiff.Internal.Types
 
   Ghc-options: -O3 -Wall
   Build-depends: base                >= 4.8     && < 5,
-                 bytestring          >= 0.9     && < 0.11,
-                 mtl                 >= 1.1     && < 2.3,
-                 binary              >= 0.5     && < 0.9,
-                 zlib                >= 0.5.3.1 && < 0.7,
+                 bytestring          >= 0.9     && < 0.13,
+                 mtl                 >= 1.1     && < 2.4,
+                 binary              >= 0.8.1   && < 0.9,
+                 zlib                >= 0.5.3.1 && < 0.8,
                  transformers        >= 0.2,
-                 vector              >= 0.10    && < 0.13,
-                 primitive           >= 0.4     && < 0.7,
-                 deepseq             >= 1.1     && < 1.5,
-                 containers          >= 0.4.2   && < 0.6
-
-  if flag(Mmap)
-    Build-depends: mmap
-    CC-Options: "-DWITH_MMAP_BYTESTRING"
+                 vector              >= 0.12.3.1,
+                 primitive           >= 0.4,
+                 deepseq             >= 1.1     && < 1.6,
+                 containers          >= 0.4.2   && < 0.8
 
   -- Modules not exported by this package.
-  Other-modules: Codec.Picture.Jpg.DefaultTable,
-                 Codec.Picture.Jpg.Metadata,
-                 Codec.Picture.Jpg.FastIdct,
-                 Codec.Picture.Jpg.FastDct,
-                 Codec.Picture.Jpg.Types,
-                 Codec.Picture.Jpg.Common,
-                 Codec.Picture.Jpg.Progressive,
-                 Codec.Picture.Gif.LZW,
-                 Codec.Picture.Gif.LZWEncoding,
-                 Codec.Picture.Png.Export,
-                 Codec.Picture.Png.Type,
-                 Codec.Picture.Png.Metadata,
-                 Codec.Picture.Tiff.Metadata,
-                 Codec.Picture.Tiff.Types,
-                 Codec.Picture.BitWriter,
+  Other-modules: Codec.Picture.BitWriter,
                  Codec.Picture.InternalHelper,
                  Codec.Picture.VectorByteConversion
 
README.md view
@@ -51,11 +51,13 @@         * in a gAMA field : 'Gamma'
         * DPI information in a pHYs chunk.
 
- - Bitmap (.bmp) (mainly used as a debug output format)
+ - Bitmap (.bmp)
     * Reading
-        - 32bits (RGBA) images
-        - 24bits (RGB) images
-        - 8bits (greyscale & paletted) images
+        - 16 or 32 bit RGBA images
+        - 16, 24, 32 bit RGB images
+        - 1, 4, or 8 bit (greyscale & paletted) images
+        - RLE encoded or uncompressed
+        - Windows 2.0/3.1/95/98 style bitmaps all supported
 
     * Writing
         - 32bits (RGBA) per pixel images
@@ -99,7 +101,9 @@ 
  - Tiff
     * Reading
-        - 2, 4, 8, 16 bit depth reading (planar and contiguous for each)
+        - 2, 4, 8, 16 int bit depth reading (planar and contiguous for each)
+        - 32 bit floating point reading
+          
         - CMYK, YCbCr, RGB, RGBA, Paletted, Greyscale
         - Uncompressed, PackBits, LZW
 
changelog view
@@ -1,6 +1,87 @@ Change log
 ==========
 
+v3.3.9 June 2024
+----------------
+
+ * Something something compilation
+
+v3.3.7 July 2022
+----------------
+
+ * Dependence fidling
+ * Jpg: do not call "error" in the parser, use fail instead.
+
+v3.3.7 March 2022
+-----------------
+
+ * Jpg: Fixing renderng bug with MCUs with single block in width and
+   multiple in height
+
+v3.3.6 October 2021
+-------------------
+
+ * Bytestring bound bump
+ * Fix bug #187.  (Some JPEGs are misidentified as SourceTiff.)
+ * Fix EXIF handling of strings of four characters or fewer.
+ * Fix endianness bug in short ExifString and ExifUndefined.
+
+
+v3.3.5 January 2020
+-------------------
+
+Maintenance release to push various pull requests onto
+hackage
+
+ * Exporting Pixel32 (will)
+ * Palettization of transparent frames in Gif (flutterlice)
+ * Documentation fixes (lehins)
+
+v3.3.4 September 2019
+---------------------
+
+ * support reading compressed zTXt metadata from PNG files (claudeha)
+ * Add helper functions to convert a DynamicImage to RGB16 (uglyoldbob)
+ * Fix RGB to CMYK conversion (lehins)
+
+v3.3.3.1 June 2019
+------------------
+
+ * New GHC maintenance (thanks to ekmett)
+
+v3.3.3 December 2018
+--------------------
+
+ * Enhanced: loading of bitmap format (thanks to CLowcay)
+ * Refactoring: exposing more internal modules (thanks to wyager)
+ * Refactoring: exposing dynamicMap & dynamicPixelMap
+   through `Codec.Picture` (thnks to LightAndLight)
+
+ * v3.3.3.1: fixing compilation with older GHC
+
+v3.3.2 October 2018
+-------------------
+
+ * Fix: GHC-8.6 compilation fix (no upper bound on base)
+ * Fix: upper bound on containers (pull request phadej)
+ * Fix: palette validation for gifs (pull request omedan)
+ * New: More complete gif creation API (pull request omedan)
+
+v3.3.1 August 2018
+------------------
+
+ * Fix: gif decoding of 1bit palette (fix Ornedan)
+ * Fix: end of stream handling for gif's lzw encoding (fix Ornedan)
+
+v3.3 July 2018
+--------------
+
+ * New: Eq instances for image
+ * Fix: color gif resolution offset
+ * New: support for Float Tiff
+ * Breaking change: New `ImageY32` constructor for `Dynamic`
+					hence the version bump.
+
 v3.2.9.5 March 2018
 -------------------
  
src/Codec/Picture.hs view
@@ -23,6 +23,8 @@                      , decodeImageWithMetadata
                      , decodeImageWithPaletteAndMetadata
                      , pixelMap
+                     , dynamicMap
+                     , dynamicPixelMap
                      , generateImage
                      , generateFoldImage
                      , withImage
@@ -30,6 +32,7 @@ 
                       -- * RGB helper functions
                      , convertRGB8
+                     , convertRGB16
                      , convertRGBA8
 
                      -- * Lens compatibility
@@ -126,6 +129,7 @@                      -- $graph
                      , Pixel8
                      , Pixel16
+                     , Pixel32
                      , PixelF
 
                      , PixelYA8( .. )
@@ -293,6 +297,20 @@ decimateWord16 (Image w h da) =
   Image w h $ VS.map (\v -> fromIntegral $ v `unsafeShiftR` 8) da
 
+decimateWord3216 :: ( Pixel px1, Pixel px2
+                  , PixelBaseComponent px1 ~ Pixel32
+                  , PixelBaseComponent px2 ~ Pixel16
+                  ) => Image px1 -> Image px2
+decimateWord3216 (Image w h da) =
+  Image w h $ VS.map (\v -> fromIntegral $ v `unsafeShiftR` 16) da
+  
+decimateWord32 :: ( Pixel px1, Pixel px2
+                  , PixelBaseComponent px1 ~ Pixel32
+                  , PixelBaseComponent px2 ~ Pixel8
+                  ) => Image px1 -> Image px2
+decimateWord32 (Image w h da) =
+  Image w h $ VS.map (\v -> fromIntegral $ v `unsafeShiftR` 24) da
+
 decimateFloat :: ( Pixel px1, Pixel px2
                  , PixelBaseComponent px1 ~ PixelF
                  , PixelBaseComponent px2 ~ Pixel8
@@ -300,9 +318,22 @@ decimateFloat (Image w h da) =
   Image w h $ VS.map (floor . (255*) . max 0 . min 1) da
 
+decimateFloat16 :: ( Pixel px1, Pixel px2
+                 , PixelBaseComponent px1 ~ PixelF
+                 , PixelBaseComponent px2 ~ Pixel16
+                 ) => Image px1 -> Image px2
+decimateFloat16 (Image w h da) =
+  Image w h $ VS.map (floor . (65535*) . max 0 . min 1) da
+
 instance Decimable Pixel16 Pixel8 where
    decimateBitDepth = decimateWord16
 
+instance Decimable Pixel32 Pixel16 where
+   decimateBitDepth = decimateWord3216
+
+instance Decimable Pixel32 Pixel8 where
+   decimateBitDepth = decimateWord32
+
 instance Decimable PixelYA16 PixelYA8 where
    decimateBitDepth = decimateWord16
 
@@ -318,16 +349,23 @@ instance Decimable PixelF Pixel8 where
    decimateBitDepth = decimateFloat
 
+instance Decimable PixelF Pixel16 where
+   decimateBitDepth = decimateFloat16
+
 instance Decimable PixelRGBF PixelRGB8 where
    decimateBitDepth = decimateFloat
 
--- | Convert by any mean possible a dynamic image to an image
+instance Decimable PixelRGBF PixelRGB16 where
+   decimateBitDepth = decimateFloat16
+
+-- | Convert by any means possible a dynamic image to an image
 -- in RGBA. The process can lose precision while converting from
 -- 16bits pixels or Floating point pixels.
 convertRGBA8 :: DynamicImage -> Image PixelRGBA8
 convertRGBA8 dynImage = case dynImage of
   ImageY8     img -> promoteImage img
   ImageY16    img -> promoteImage (decimateBitDepth img :: Image Pixel8)
+  ImageY32    img -> promoteImage (decimateBitDepth img :: Image Pixel8)
   ImageYF     img -> promoteImage (decimateBitDepth img :: Image Pixel8)
   ImageYA8    img -> promoteImage img
   ImageYA16   img -> promoteImage (decimateBitDepth img :: Image PixelYA8)
@@ -341,7 +379,7 @@   ImageCMYK16 img ->
     promoteImage (convertImage (decimateBitDepth img :: Image PixelCMYK8) :: Image PixelRGB8)
 
--- | Convert by any mean possible a dynamic image to an image
+-- | Convert by any means possible a dynamic image to an image
 -- in RGB. The process can lose precision while converting from
 -- 16bits pixels or Floating point pixels. Any alpha layer will
 -- be dropped
@@ -349,6 +387,7 @@ convertRGB8 dynImage = case dynImage of
   ImageY8     img -> promoteImage img
   ImageY16    img -> promoteImage (decimateBitDepth img :: Image Pixel8)
+  ImageY32    img -> promoteImage (decimateBitDepth img :: Image Pixel8)
   ImageYF     img -> promoteImage (decimateBitDepth img :: Image Pixel8)
   ImageYA8    img -> promoteImage img
   ImageYA16   img -> promoteImage (decimateBitDepth img :: Image PixelYA8)
@@ -360,6 +399,27 @@   ImageYCbCr8 img -> convertImage img
   ImageCMYK8  img -> convertImage img
   ImageCMYK16 img -> convertImage (decimateBitDepth img :: Image PixelCMYK8)
+  
+-- | Convert by any means possible a dynamic image to an image
+-- in RGB. The process can lose precision while converting from
+-- 32bits pixels or Floating point pixels. Any alpha layer will
+-- be dropped
+convertRGB16 :: DynamicImage -> Image PixelRGB16
+convertRGB16 dynImage = case dynImage of
+  ImageY8     img -> promoteImage img
+  ImageY16    img -> promoteImage img
+  ImageY32    img -> promoteImage (decimateBitDepth img :: Image Pixel16)
+  ImageYF     img -> promoteImage (decimateBitDepth img :: Image Pixel16)
+  ImageYA8    img -> promoteImage img
+  ImageYA16   img -> promoteImage img
+  ImageRGB8   img -> promoteImage img
+  ImageRGB16  img -> img
+  ImageRGBF   img -> decimateBitDepth img :: Image PixelRGB16
+  ImageRGBA8  img -> dropAlphaLayer (promoteImage img :: Image PixelRGBA16)
+  ImageRGBA16 img -> dropAlphaLayer img
+  ImageYCbCr8 img -> promoteImage (convertImage img :: Image PixelRGB8)
+  ImageCMYK8  img -> promoteImage (convertImage img :: Image PixelRGB8)
+  ImageCMYK16 img -> convertImage img
 
 -- | Equivalent to 'decodeImage', but also provide potential metadatas
 -- present in the given file and the palettes if the format provides them.
src/Codec/Picture/BitWriter.hs view
@@ -19,6 +19,7 @@                               , BoolWriteStateRef 
                               , newWriteStateRef
                               , finalizeBoolWriter
+                              , finalizeBoolWriterGif
                               , writeBits'
                               , writeBitsGif
 
@@ -339,6 +340,19 @@ 
               where cleanMask = (1 `unsafeShiftL` bitCount) - 1 :: Word32
                     cleanData = bitData .&. cleanMask     :: Word32
+
+finalizeBoolWriterGif :: BoolWriteStateRef s -> ST s L.ByteString
+finalizeBoolWriterGif st = do
+    flushLeftBitsGif st
+    forceBufferFlushing' st
+    L.fromChunks <$> readSTRef (bwsBufferList st)
+
+flushLeftBitsGif :: BoolWriteStateRef s -> ST s ()
+flushLeftBitsGif st = do
+    currCount <- readSTRef $ bwsBitReaded st
+    when (currCount > 0) $ do
+      currWord <- readSTRef $ bwsBitAcc st
+      pushByte' st currWord
 
 {-# ANN module "HLint: ignore Reduce duplication" #-}
 
src/Codec/Picture/Bitmap.hs view
@@ -12,9 +12,9 @@                            , decodeBitmap
                            , decodeBitmapWithMetadata
                            , decodeBitmapWithPaletteAndMetadata
-                           , encodeDynamicBitmap 
+                           , encodeDynamicBitmap
                            , encodeBitmapWithPaletteAndMetadata
-                           , writeDynamicBitmap 
+                           , writeDynamicBitmap
                              -- * Accepted format in output
                            , BmpEncodable( )
                            ) where
@@ -25,7 +25,7 @@ #endif
 
 import Control.Arrow( first )
-import Control.Monad( replicateM, when, foldM_, forM_ )
+import Control.Monad( replicateM, when, foldM_, forM_, void )
 import Control.Monad.ST ( ST, runST )
 import Data.Maybe( fromMaybe )
 import qualified Data.Vector.Storable as VS
@@ -33,23 +33,28 @@ import Data.Binary( Binary( .. ) )
 import Data.Binary.Put( Put
                       , runPut
+                      , putInt32le
                       , putWord16le
                       , putWord32le
-                      , putByteString 
+                      , putByteString
                       )
 
 import Data.Binary.Get( Get
                       , getWord8
-                      , getWord16le 
+                      , getWord16le
                       , getWord32le
-                      , getWord32be
+                      , getInt32le
+                      , getByteString
                       , bytesRead
                       , skip
+                      , label
                       )
 
+import Data.Bits
 import Data.Int( Int32 )
 import Data.Word( Word32, Word16, Word8 )
 import qualified Data.ByteString as B
+import qualified Data.ByteString.Internal as BI
 import qualified Data.ByteString.Lazy as L
 
 import Codec.Picture.InternalHelper
@@ -93,8 +98,43 @@             , dataOffset = offset
             }
 
+-- | The type of color space declared in a Windows BMP file.
+data ColorSpaceType = CalibratedRGB
+                    | DeviceDependentRGB
+                    | DeviceDependentCMYK
+                    | SRGB
+                    | WindowsColorSpace
+                    | ProfileEmbedded
+                    | ProfileLinked
+                    | UnknownColorSpace Word32
+                    deriving (Eq, Show)
 
-data BmpInfoHeader = BmpInfoHeader
+-- | BITMAPxHEADER with compatibility up to V5. This header was first introduced
+-- with Windows 2.0 as the BITMAPCOREHEADER, and was later extended in Windows
+-- 3.1, Windows 95 and Windows 98. The original BITMAPCOREHEADER includes all
+-- fields up to 'bitPerPixel'. The Windows 3.1 BITMAPINFOHEADER adds all the
+-- fields up to 'importantColors'.
+--
+-- Some Windows 3.1 bitmaps with 16 or 32 bits per pixel might also have three
+-- bitmasks following the BITMAPINFOHEADER. These bitmasks were later
+-- incorporated into the bitmap header structure in the unreleased
+-- BITMAPV2INFOHEADER. The (also unreleased) BITMAPV3INFOHEADER added another
+-- bitmask for an alpha channel.
+--
+-- The later Windows 95 and Windows 98 extensions to the BITMAPINFOHEADER extend
+-- the BITMAPV3INFOHEADER, adding support for color correction.
+--
+--  * BITMAPV4HEADER (Windows 95) may include a simple color profile in a
+--      proprietary format. The fields in this color profile (which includes gamma
+--      values) are not to be used unless the 'colorSpaceType' field is
+--      'CalibratedRGB'.
+--
+--  * BITMAPV5HEADER (Windows 98) adds support for an ICC color profile. The
+--      presence of an ICC color profile is indicated by setting the 'colorSpaceType'
+--      field to 'ProfileEmbedded' or 'ProfileLinked'. If it is 'ProfileLinked' then
+--      the profile data is actually a Windows-1252 encoded string containing the
+--      fully qualified path to an ICC color profile.
+data BmpV5Header = BmpV5Header
     { size              :: !Word32 -- Header size in bytes
     , width             :: !Int32
     , height            :: !Int32
@@ -102,67 +142,224 @@     , bitPerPixel       :: !Word16
     , bitmapCompression :: !Word32
     , byteImageSize     :: !Word32
-    , xResolution       :: !Int32 -- ^ Pixels per meter
-    , yResolution       :: !Int32 -- ^ Pixels per meter
-    , colorCount        :: !Word32
+    , xResolution       :: !Int32  -- ^ Pixels per meter
+    , yResolution       :: !Int32  -- ^ Pixels per meter
+    , colorCount        :: !Word32 -- ^ Number of colors in the palette
     , importantColours  :: !Word32
+    -- Fields added to the header in V2
+    , redMask           :: !Word32 -- ^ Red bitfield mask, set to 0 if not used
+    , greenMask         :: !Word32 -- ^ Green bitfield mask, set to 0 if not used
+    , blueMask          :: !Word32 -- ^ Blue bitfield mask, set to 0 if not used
+    -- Fields added to the header in V3
+    , alphaMask         :: !Word32 -- ^ Alpha bitfield mask, set to 0 if not used
+    -- Fields added to the header in V4
+    , colorSpaceType    :: !ColorSpaceType
+    , colorSpace        :: !B.ByteString -- ^ Windows color space, not decoded
+    -- Fields added to the header in V5
+    , iccIntent         :: !Word32
+    , iccProfileData    :: !Word32
+    , iccProfileSize    :: !Word32
     }
     deriving Show
 
-sizeofBmpHeader, sizeofBmpInfo  :: Word32
+-- | Size of the Windows BITMAPV4INFOHEADER color space information.
+sizeofColorProfile :: Int
+sizeofColorProfile = 48
+
+-- | Sizes of basic BMP headers.
+sizeofBmpHeader, sizeofBmpCoreHeader, sizeofBmpInfoHeader :: Word32
 sizeofBmpHeader = 2 + 4 + 2 + 2 + 4
-sizeofBmpInfo = 3 * 4 + 2 * 2 + 6 * 4
+sizeofBmpCoreHeader = 12
+sizeofBmpInfoHeader = 40
 
-instance Binary BmpInfoHeader where
+-- | Sizes of extended BMP headers.
+sizeofBmpV2Header, sizeofBmpV3Header, sizeofBmpV4Header, sizeofBmpV5Header :: Word32
+sizeofBmpV2Header = 52
+sizeofBmpV3Header = 56
+sizeofBmpV4Header = 108
+sizeofBmpV5Header = 124
+
+instance Binary ColorSpaceType where
+    put CalibratedRGB         = putWord32le 0
+    put DeviceDependentRGB    = putWord32le 1
+    put DeviceDependentCMYK   = putWord32le 2
+    put ProfileEmbedded       = putWord32le 0x4D424544
+    put ProfileLinked         = putWord32le 0x4C494E4B
+    put SRGB                  = putWord32le 0x73524742
+    put WindowsColorSpace     = putWord32le 0x57696E20
+    put (UnknownColorSpace x) = putWord32le x
+    get = do
+      w <- getWord32le
+      return $ case w of
+        0          -> CalibratedRGB
+        1          -> DeviceDependentRGB
+        2          -> DeviceDependentCMYK
+        0x4D424544 -> ProfileEmbedded
+        0x4C494E4B -> ProfileLinked
+        0x73524742 -> SRGB
+        0x57696E20 -> WindowsColorSpace
+        _          -> UnknownColorSpace w
+
+instance Binary BmpV5Header where
     put hdr = do
         putWord32le $ size hdr
-        putWord32le . fromIntegral $ width hdr
-        putWord32le . fromIntegral $ height hdr
-        putWord16le $ planes hdr
-        putWord16le $ bitPerPixel hdr
-        putWord32le $ bitmapCompression hdr
-        putWord32le $ byteImageSize hdr
-        putWord32le . fromIntegral $ xResolution hdr
-        putWord32le . fromIntegral $ yResolution hdr
-        putWord32le $ colorCount hdr
-        putWord32le $ importantColours hdr
 
+        if (size hdr == sizeofBmpCoreHeader) then do
+          putWord16le . fromIntegral $ width hdr
+          putWord16le . fromIntegral $ height hdr
+          putWord16le $ planes hdr
+          putWord16le $ bitPerPixel hdr
+        else do
+          putInt32le $ width hdr
+          putInt32le $ height hdr
+          putWord16le $ planes hdr
+          putWord16le $ bitPerPixel hdr
+
+        when (size hdr > sizeofBmpCoreHeader) $ do
+          putWord32le $ bitmapCompression hdr
+          putWord32le $ byteImageSize hdr
+          putInt32le $ xResolution hdr
+          putInt32le $ yResolution hdr
+          putWord32le $ colorCount hdr
+          putWord32le $ importantColours hdr
+
+        when (size hdr > sizeofBmpInfoHeader || bitmapCompression hdr == 3) $ do
+          putWord32le $ redMask hdr
+          putWord32le $ greenMask hdr
+          putWord32le $ blueMask hdr
+
+        when (size hdr > sizeofBmpV2Header) $
+          putWord32le $ alphaMask hdr
+
+        when (size hdr > sizeofBmpV3Header) $ do
+          put $ colorSpaceType hdr
+          putByteString $ colorSpace hdr
+
+        when (size hdr > sizeofBmpV4Header) $ do
+          put $ iccIntent hdr
+          putWord32le $ iccProfileData hdr
+          putWord32le $ iccProfileSize hdr
+          putWord32le 0 -- reserved field
+
     get = do
-        readSize <- getWord32le
-        readWidth <- fromIntegral <$> getWord32le
-        readHeight <- fromIntegral <$> getWord32le
-        readPlanes <- getWord16le
-        readBitPerPixel <- getWord16le
-        readBitmapCompression <- getWord32le
-        readByteImageSize <- getWord32le
-        readXResolution <- fromIntegral <$> getWord32le
-        readYResolution <- fromIntegral <$> getWord32le
-        readColorCount <- getWord32le
-        readImportantColours <- getWord32le
-        return BmpInfoHeader {
-            size = readSize,
-            width = readWidth,
-            height = readHeight,
-            planes = readPlanes,
-            bitPerPixel = readBitPerPixel,
-            bitmapCompression = readBitmapCompression,
-            byteImageSize = readByteImageSize,
-            xResolution = readXResolution,
-            yResolution = readYResolution,
-            colorCount = readColorCount,
-            importantColours = readImportantColours
-        }
+      readSize <- getWord32le
+      if readSize == sizeofBmpCoreHeader
+        then getBitmapCoreHeader readSize
+        else getBitmapInfoHeader readSize
 
+      where
+        getBitmapCoreHeader readSize = do
+          readWidth <- getWord16le
+          readHeight <- getWord16le
+          readPlanes <- getWord16le
+          readBitPerPixel <- getWord16le
+          return BmpV5Header {
+              size = readSize,
+              width = fromIntegral readWidth,
+              height = fromIntegral readHeight,
+              planes = readPlanes,
+              bitPerPixel = readBitPerPixel,
+              bitmapCompression = 0,
+              byteImageSize = 0,
+              xResolution = 2835,
+              yResolution = 2835,
+              colorCount = 2 ^ readBitPerPixel,
+              importantColours = 0,
+              redMask = 0,
+              greenMask = 0,
+              blueMask = 0,
+              alphaMask = 0,
+              colorSpaceType = DeviceDependentRGB,
+              colorSpace = B.empty,
+              iccIntent = 0,
+              iccProfileData = 0,
+              iccProfileSize = 0
+          }
+
+        getBitmapInfoHeader readSize = do
+          readWidth <- getInt32le
+          readHeight <- getInt32le
+          readPlanes <- getWord16le
+          readBitPerPixel <- getWord16le
+          readBitmapCompression <- getWord32le
+          readByteImageSize <- getWord32le
+          readXResolution <- getInt32le
+          readYResolution <- getInt32le
+          readColorCount <- getWord32le
+          readImportantColours <- getWord32le
+
+          (readRedMask, readGreenMask, readBlueMask) <-
+            if readSize == sizeofBmpInfoHeader && readBitmapCompression /= 3
+              then return (0, 0, 0)
+              else do
+                -- fields added to the header in V2, but sometimes present
+                -- immediately after a plain BITMAPINFOHEADER
+                innerReadRedMask <- getWord32le
+                innerReadGreenMask <- getWord32le
+                innerReadBlueMask <- getWord32le
+                return (innerReadRedMask, innerReadGreenMask, innerReadBlueMask)
+
+          -- field added in V3 (undocumented)
+          readAlphaMask <- if readSize < sizeofBmpV3Header then return 0 else getWord32le
+
+          (readColorSpaceType, readColorSpace) <-
+            if readSize < sizeofBmpV4Header
+              then return (DeviceDependentRGB, B.empty)
+              else do
+                -- fields added in V4 (Windows 95)
+                csType <- get
+                cs <- getByteString sizeofColorProfile
+                return (csType, cs)
+
+          (readIccIntent, readIccProfileData, readIccProfileSize) <-
+            if readSize < sizeofBmpV5Header
+              then return (0, 0, 0)
+              else do
+                -- fields added in V5 (Windows 98)
+                innerIccIntent <- getWord32le
+                innerIccProfileData <- getWord32le
+                innerIccProfileSize <- getWord32le
+                void getWord32le -- reserved field
+                return (innerIccIntent, innerIccProfileData, innerIccProfileSize)
+
+          return BmpV5Header {
+              size = readSize,
+              width = readWidth,
+              height = readHeight,
+              planes = readPlanes,
+              bitPerPixel = readBitPerPixel,
+              bitmapCompression = readBitmapCompression,
+              byteImageSize = readByteImageSize,
+              xResolution = readXResolution,
+              yResolution = readYResolution,
+              colorCount = readColorCount,
+              importantColours = readImportantColours,
+              redMask = readRedMask,
+              greenMask = readGreenMask,
+              blueMask = readBlueMask,
+              alphaMask = readAlphaMask,
+              colorSpaceType = readColorSpaceType,
+              colorSpace = readColorSpace,
+              iccIntent = readIccIntent,
+              iccProfileData = readIccProfileData,
+              iccProfileSize = readIccProfileSize
+          }
+
 newtype BmpPalette = BmpPalette [(Word8, Word8, Word8, Word8)]
 
 putPalette :: BmpPalette -> Put
 putPalette (BmpPalette p) = mapM_ (\(r, g, b, a) -> put r >> put g >> put b >> put a) p
 
+putICCProfile :: Maybe B.ByteString -> Put
+putICCProfile Nothing = return ()
+putICCProfile (Just bytes) = put bytes
+
 -- | All the instance of this class can be written as a bitmap file
 -- using this library.
 class BmpEncodable pixel where
     bitsPerPixel   :: pixel -> Int
     bmpEncode      :: Image pixel -> Put
+    hasAlpha       :: Image pixel -> Bool
     defaultPalette :: pixel -> BmpPalette
     defaultPalette _ = BmpPalette []
 
@@ -175,6 +372,7 @@            inner (ix + 1) (n - 1)
 
 instance BmpEncodable Pixel8 where
+    hasAlpha _ = False
     defaultPalette _ = BmpPalette [(x,x,x, 255) | x <- [0 .. 255]]
     bitsPerPixel _ = 8
     bmpEncode (Image {imageWidth = w, imageHeight = h, imageData = arr}) =
@@ -200,8 +398,9 @@                   VS.unsafeFreeze buff
 
 instance BmpEncodable PixelRGBA8 where
+    hasAlpha _ = True
     bitsPerPixel _ = 32
-    bmpEncode (Image {imageWidth = w, imageHeight = h, imageData = arr}) = 
+    bmpEncode (Image {imageWidth = w, imageHeight = h, imageData = arr}) =
       forM_ [h - 1, h - 2 .. 0] $ \l -> putVector $ runST $ putLine l
       where
         putVector vec = putByteString . blitVector vec 0 $ w * 4
@@ -228,6 +427,7 @@             VS.unsafeFreeze buff
 
 instance BmpEncodable PixelRGB8 where
+    hasAlpha _ = False
     bitsPerPixel _ = 24
     bmpEncode (Image {imageWidth = w, imageHeight = h, imageData = arr}) =
        forM_ [h - 1, h - 2 .. 0] $ \l -> putVector $ runST $ putLine l
@@ -245,7 +445,7 @@                       let r = arr `VS.unsafeIndex` readIdx
                           g = arr `VS.unsafeIndex` (readIdx + 1)
                           b = arr `VS.unsafeIndex` (readIdx + 2)
-                      
+
                       (buff `M.unsafeWrite` writeIdx) b
                       (buff `M.unsafeWrite` (writeIdx + 1)) g
                       (buff `M.unsafeWrite` (writeIdx + 2)) r
@@ -255,8 +455,76 @@               inner 0 0 initialIndex
               VS.unsafeFreeze buff
 
-decodeImageRGBA8 :: BmpInfoHeader -> (Int, Int, Int, Int) -> B.ByteString -> Image PixelRGBA8
-decodeImageRGBA8 (BmpInfoHeader { width = w, height = h }) (posR, posG, posB, posA) str = Image wi hi stArray where
+-- | Information required to extract data from a bitfield.
+data Bitfield t = Bitfield
+    { bfMask :: !t            -- ^ The original bitmask.
+    , bfShift :: !Int         -- ^ The computed number of bits to shift right.
+    , bfScale :: !Float       -- ^ The scale factor to fit the data into 8 bits.
+    } deriving (Eq, Show)
+
+-- | Four bitfields (red, green, blue, alpha)
+data Bitfields4 t = Bitfields4 !(Bitfield t)
+                               !(Bitfield t)
+                               !(Bitfield t)
+                               !(Bitfield t)
+                               deriving (Eq, Show)
+
+-- | Default bitfields 32 bit bitmaps.
+defaultBitfieldsRGB32 :: Bitfields3 Word32
+defaultBitfieldsRGB32 = Bitfields3 (makeBitfield 0x00FF0000)
+                                   (makeBitfield 0x0000FF00)
+                                   (makeBitfield 0x000000FF)
+
+-- | Default bitfields for 16 bit bitmaps.
+defaultBitfieldsRGB16 :: Bitfields3 Word16
+defaultBitfieldsRGB16 = Bitfields3 (makeBitfield 0x7C00)
+                                   (makeBitfield 0x03E0)
+                                   (makeBitfield 0x001F)
+
+-- | Three bitfields (red, gree, blue).
+data Bitfields3 t = Bitfields3 !(Bitfield t)
+                               !(Bitfield t)
+                               !(Bitfield t)
+                               deriving (Eq, Show)
+
+-- | Pixel formats used to encode RGBA image data.
+data RGBABmpFormat = RGBA32 !(Bitfields4 Word32)
+                   | RGBA16 !(Bitfields4 Word16)
+                   deriving (Eq, Show)
+
+-- | Pixel formats used to encode RGB image data.
+data RGBBmpFormat = RGB32 !(Bitfields3 Word32)
+                  | RGB24
+                  | RGB16 !(Bitfields3 Word16)
+                  deriving (Eq, Show)
+
+-- | Pixel formats used to encode indexed or grayscale images.
+data IndexedBmpFormat = OneBPP | FourBPP | EightBPP deriving Show
+
+-- | Extract pixel data from a bitfield.
+extractBitfield :: (FiniteBits t, Integral t) => Bitfield t -> t -> Word8
+extractBitfield bf t = if bfScale bf == 1
+                        then fromIntegral field
+                        else round $ bfScale bf * fromIntegral field
+  where field = (t .&. bfMask bf) `unsafeShiftR` bfShift bf
+
+-- | Convert a bit mask into a 'BitField'.
+makeBitfield :: (FiniteBits t, Integral t) => t -> Bitfield t
+makeBitfield mask = Bitfield mask shiftBits scale
+  where
+    shiftBits = countTrailingZeros mask
+    scale = 255 / fromIntegral (mask `unsafeShiftR` shiftBits)
+
+-- | Helper method to cast a 'B.ByteString' to a 'VS.Vector' of some type.
+castByteString :: VS.Storable a => B.ByteString -> VS.Vector a
+#if MIN_VERSION_bytestring(0,11,0)
+castByteString (BI.BS fp len) = VS.unsafeCast $ VS.unsafeFromForeignPtr fp 0 len
+#else
+castByteString (BI.PS fp offset len) = VS.unsafeCast $ VS.unsafeFromForeignPtr fp offset len
+#endif
+
+decodeImageRGBA8 :: RGBABmpFormat -> BmpV5Header -> B.ByteString -> Image PixelRGBA8
+decodeImageRGBA8 pixelFormat (BmpV5Header { width = w, height = h, bitPerPixel = bpp }) str = Image wi hi stArray where
   wi = fromIntegral w
   hi = abs $ fromIntegral h
   stArray = runST $ do
@@ -267,24 +535,38 @@         foldM_ (readLine arr) 0 [hi - 1, hi - 2 .. 0]
       VS.unsafeFreeze arr
 
-  stride = linePadding 32 wi -- will be 0
+  paddingWords = (8 * linePadding intBPP wi) `div` intBPP
+  intBPP = fromIntegral bpp
 
   readLine :: forall s. M.MVector s Word8 -> Int -> Int -> ST s Int
-  readLine arr readIndex line = inner readIndex writeIndex where
-    lastIndex = wi * (hi - 1 - line + 1) * 4
-    writeIndex = wi * (hi - 1 - line) * 4
+  readLine arr readIndex line = case pixelFormat of
+      RGBA32 bitfields -> inner bitfields (castByteString str) readIndex writeIndex
+      RGBA16 bitfields -> inner bitfields (castByteString str) readIndex writeIndex
+    where
+      lastIndex = wi * (hi - 1 - line + 1) * 4
+      writeIndex = wi * (hi - 1 - line) * 4
 
-    inner readIdx writeIdx | writeIdx >= lastIndex = return $ readIdx + stride
-    inner readIdx writeIdx = do
-        -- 32-bit BMP pixels are BGRA
-        (arr `M.unsafeWrite`  writeIdx     ) (str `B.index` (readIdx + posR))
-        (arr `M.unsafeWrite` (writeIdx + 1)) (str `B.index` (readIdx + posG))
-        (arr `M.unsafeWrite` (writeIdx + 2)) (str `B.index` (readIdx + posB))
-        (arr `M.unsafeWrite` (writeIdx + 3)) (str `B.index` (readIdx + posA))
-        inner (readIdx + 4) (writeIdx + 4)
+      inner
+        :: (FiniteBits t, Integral t, M.Storable t, Show t)
+        => Bitfields4 t
+        -> VS.Vector t
+        -> Int
+        -> Int
+        -> ST s Int
+      inner (Bitfields4 r g b a) inStr = inner0
+        where
+          inner0 :: Int -> Int -> ST s Int
+          inner0 readIdx writeIdx | writeIdx >= lastIndex = return $ readIdx + paddingWords
+          inner0 readIdx writeIdx = do
+            let word = inStr VS.! readIdx
+            (arr `M.unsafeWrite`  writeIdx     ) (extractBitfield r word)
+            (arr `M.unsafeWrite` (writeIdx + 1)) (extractBitfield g word)
+            (arr `M.unsafeWrite` (writeIdx + 2)) (extractBitfield b word)
+            (arr `M.unsafeWrite` (writeIdx + 3)) (extractBitfield a word)
+            inner0 (readIdx + 1) (writeIdx + 4)
 
-decodeImageRGB8 :: BmpInfoHeader -> B.ByteString -> Image PixelRGB8
-decodeImageRGB8 (BmpInfoHeader { width = w, height = h }) str = Image wi hi stArray where
+decodeImageRGB8 :: RGBBmpFormat -> BmpV5Header -> B.ByteString -> Image PixelRGB8
+decodeImageRGB8 pixelFormat (BmpV5Header { width = w, height = h, bitPerPixel = bpp }) str = Image wi hi stArray where
   wi = fromIntegral w
   hi = abs $ fromIntegral h
   stArray = runST $ do
@@ -295,22 +577,46 @@         foldM_ (readLine arr) 0 [hi - 1, hi - 2 .. 0]
       VS.unsafeFreeze arr
 
-  stride = linePadding 24 wi
+  paddingBytes = linePadding intBPP wi
+  paddingWords = (linePadding intBPP wi * 8) `div` intBPP
+  intBPP = fromIntegral bpp
 
   readLine :: forall s. M.MVector s Word8 -> Int -> Int -> ST s Int
-  readLine arr readIndex line = inner readIndex writeIndex where
-    lastIndex = wi * (hi - 1 - line + 1) * 3
-    writeIndex = wi * (hi - 1 - line) * 3
+  readLine arr readIndex line = case pixelFormat of
+      RGB16 bitfields -> innerBF bitfields (castByteString str) readIndex writeIndex
+      RGB32 bitfields -> innerBF bitfields (castByteString str) readIndex writeIndex
+      RGB24 -> inner24 readIndex writeIndex
+    where
+      lastIndex = wi * (hi - 1 - line + 1) * 3
+      writeIndex = wi * (hi - 1 - line) * 3
 
-    inner readIdx writeIdx | writeIdx >= lastIndex = return $ readIdx + stride
-    inner readIdx writeIdx = do
-        (arr `M.unsafeWrite`  writeIdx     ) (str `B.index` (readIdx + 2))
-        (arr `M.unsafeWrite` (writeIdx + 1)) (str `B.index` (readIdx + 1))
-        (arr `M.unsafeWrite` (writeIdx + 2)) (str `B.index`  readIdx)
-        inner (readIdx + 3) (writeIdx + 3)
+      inner24 readIdx writeIdx | writeIdx >= lastIndex = return $ readIdx + paddingBytes
+      inner24 readIdx writeIdx = do
+          (arr `M.unsafeWrite`  writeIdx     ) (str `B.index` (readIdx + 2))
+          (arr `M.unsafeWrite` (writeIdx + 1)) (str `B.index` (readIdx + 1))
+          (arr `M.unsafeWrite` (writeIdx + 2)) (str `B.index`  readIdx)
+          inner24 (readIdx + 3) (writeIdx + 3)
 
-decodeImageY8 :: BmpInfoHeader -> B.ByteString -> Image Pixel8
-decodeImageY8 (BmpInfoHeader { width = w, height = h }) str = Image wi hi stArray where
+      innerBF
+        :: (FiniteBits t, Integral t, M.Storable t, Show t)
+        => Bitfields3 t
+        -> VS.Vector t
+        -> Int
+        -> Int
+        -> ST s Int
+      innerBF (Bitfields3 r g b) inStr = innerBF0
+        where
+          innerBF0 :: Int -> Int -> ST s Int
+          innerBF0 readIdx writeIdx | writeIdx >= lastIndex = return $ readIdx + paddingWords
+          innerBF0 readIdx writeIdx = do
+            let word = inStr VS.! readIdx
+            (arr `M.unsafeWrite`  writeIdx     ) (extractBitfield r word)
+            (arr `M.unsafeWrite` (writeIdx + 1)) (extractBitfield g word)
+            (arr `M.unsafeWrite` (writeIdx + 2)) (extractBitfield b word)
+            innerBF0 (readIdx + 1) (writeIdx + 3)
+
+decodeImageY8 :: IndexedBmpFormat -> BmpV5Header -> B.ByteString -> Image Pixel8
+decodeImageY8 lowBPP (BmpV5Header { width = w, height = h, bitPerPixel = bpp }) str = Image wi hi stArray where
   wi = fromIntegral w
   hi = abs $ fromIntegral h
   stArray = runST $ do
@@ -321,33 +627,131 @@         foldM_ (readLine arr) 0 [hi - 1, hi - 2 .. 0]
       VS.unsafeFreeze arr
 
-  stride = linePadding 8 wi
-  
+  padding = linePadding (fromIntegral bpp) wi
+
   readLine :: forall s. M.MVector s Word8 -> Int -> Int -> ST s Int
-  readLine arr readIndex line = inner readIndex writeIndex where
-    lastIndex = wi * (hi - 1 - line + 1)
-    writeIndex = wi * (hi - 1 - line)
+  readLine arr readIndex line = case lowBPP of
+      OneBPP -> inner1 readIndex writeIndex
+      FourBPP -> inner4 readIndex writeIndex
+      EightBPP -> inner8 readIndex writeIndex
+    where
+      lastIndex = wi * (hi - 1 - line + 1)
+      writeIndex = wi * (hi - 1 - line)
 
-    inner readIdx writeIdx | writeIdx >= lastIndex = return $ readIdx + stride
-    inner readIdx writeIdx = do
-      (arr `M.unsafeWrite` writeIdx) (str `B.index` readIdx)
-      inner (readIdx + 1) (writeIdx + 1)
+      inner8 readIdx writeIdx | writeIdx >= lastIndex = return $ readIdx + padding
+      inner8 readIdx writeIdx = do
+        (arr `M.unsafeWrite` writeIdx) (str `B.index` readIdx)
+        inner8 (readIdx + 1) (writeIdx + 1)
 
+      inner4 readIdx writeIdx | writeIdx >= lastIndex = return $ readIdx + padding
+      inner4 readIdx writeIdx = do
+        let byte = str `B.index` readIdx
+        if writeIdx >= lastIndex - 1 then do
+          (arr `M.unsafeWrite` writeIdx) (byte `unsafeShiftR` 4)
+          inner4 (readIdx + 1) (writeIdx + 1)
+        else do
+          (arr `M.unsafeWrite` writeIdx) (byte `unsafeShiftR` 4)
+          (arr `M.unsafeWrite` (writeIdx + 1)) (byte .&. 0x0F)
+          inner4 (readIdx + 1) (writeIdx + 2)
 
-pixelGet :: Get [Word8]
-pixelGet = do
+      inner1 readIdx writeIdx | writeIdx >= lastIndex = return $ readIdx + padding
+      inner1 readIdx writeIdx = do
+        let byte = str `B.index` readIdx
+        let toWrite = (lastIndex - writeIdx) `min` 8
+        forM_ [0 .. (toWrite - 1)] $ \i ->
+          when (byte `testBit` (7 - i)) $ (arr `M.unsafeWrite` (writeIdx + i)) 1
+        inner1 (readIdx + 1) (writeIdx + toWrite)
+
+decodeImageY8RLE :: Bool -> BmpV5Header -> B.ByteString -> Image Pixel8
+decodeImageY8RLE is4bpp (BmpV5Header { width = w, height = h, byteImageSize = sz }) str = Image wi hi stArray where
+  wi = fromIntegral w
+  hi = abs $ fromIntegral h
+  xOffsetMax = wi - 1
+
+  stArray = runST $ do
+    arr <- M.new . fromIntegral $ w * abs h
+    decodeRLE arr (B.unpack (B.take (fromIntegral sz) str)) ((hi - 1) * wi, 0)
+    VS.unsafeFreeze arr
+
+  decodeRLE :: forall s . M.MVector s Word8 -> [Word8] -> (Int, Int) -> ST s ()
+  decodeRLE arr = inner
+    where
+      inner :: [Word8] -> (Int, Int) -> ST s ()
+      inner [] _ = return ()
+      inner (0 : 0 : rest) (yOffset, _) = inner rest (yOffset - wi, 0)
+      inner (0 : 1 : _) _ = return ()
+      inner (0 : 2 : hOffset : vOffset : rest) (yOffset, _) =
+        inner rest (yOffset - (wi * fromIntegral vOffset), fromIntegral hOffset)
+      inner (0 : n : rest) writePos =
+        let isPadded = if is4bpp then (n + 3) .&. 0x3 < 2 else odd n
+        in copyN isPadded (fromIntegral n) rest writePos
+      inner (n : b : rest) writePos = writeN (fromIntegral n) b rest writePos
+      inner _ _ = return ()
+
+      -- | Write n copies of a byte to the output array.
+      writeN :: Int -> Word8 -> [Word8] -> (Int, Int) -> ST s ()
+      writeN 0 _ rest writePos = inner rest writePos
+      writeN n b rest writePos =
+        case (is4bpp, n) of
+          (True, 1) ->
+            writeByte (b `unsafeShiftR` 4) writePos >>= writeN (n - 1) b rest
+          (True, _) ->
+            writeByte (b `unsafeShiftR` 4) writePos
+              >>= writeByte (b .&. 0x0F) >>= writeN (n - 2) b rest
+          (False, _) ->
+            writeByte b writePos >>= writeN (n - 1) b rest
+
+      -- | Copy the next byte to the output array, possibly ignoring a padding byte at the end.
+      copyN :: Bool -> Int -> [Word8] -> (Int, Int) -> ST s ()
+      copyN _ _ [] _ = return ()
+      copyN False 0 rest writePos = inner rest writePos
+      copyN True 0 (_:rest) writePos = inner rest writePos
+      copyN isPadded n (b : rest) writePos =
+        case (is4bpp, n) of
+          (True, 1) ->
+            writeByte (b `unsafeShiftR` 4) writePos >>= copyN isPadded (n - 1) rest
+          (True, _) ->
+            writeByte (b `unsafeShiftR` 4) writePos
+              >>= writeByte (b .&. 0x0F) >>= copyN isPadded (n - 2) rest
+          (False, _) ->
+            writeByte b writePos >>= copyN isPadded (n - 1) rest
+
+      -- | Write the next byte to the output array.
+      writeByte :: Word8 -> (Int, Int) -> ST s (Int, Int)
+      writeByte byte (yOffset, xOffset) = do
+        (arr `M.unsafeWrite` (yOffset + xOffset)) byte
+        return (yOffset, (xOffset + 1) `min` xOffsetMax)
+
+pixel4Get :: Get [Word8]
+pixel4Get = do
     b <- getWord8
     g <- getWord8
     r <- getWord8
     _ <- getWord8
-    return $ [r, g, b]
+    return [r, g, b]
 
-metadataOfHeader :: BmpInfoHeader -> Metadatas
-metadataOfHeader hdr = 
-  Met.simpleMetadata Met.SourceBitmap (width hdr) (abs $ height hdr) dpiX dpiY
+pixel3Get :: Get [Word8]
+pixel3Get = do
+    b <- getWord8
+    g <- getWord8
+    r <- getWord8
+    return [r, g, b]
+
+metadataOfHeader :: BmpV5Header -> Maybe B.ByteString -> Metadatas
+metadataOfHeader hdr iccProfile =
+    cs `mappend` Met.simpleMetadata Met.SourceBitmap (width hdr) (abs $ height hdr) dpiX dpiY
   where
     dpiX = Met.dotsPerMeterToDotPerInch . fromIntegral $ xResolution hdr
     dpiY = Met.dotsPerMeterToDotPerInch . fromIntegral $ yResolution hdr
+    cs = case colorSpaceType hdr of
+          CalibratedRGB -> Met.singleton
+            Met.ColorSpace (Met.WindowsBitmapColorSpace $ colorSpace hdr)
+          SRGB -> Met.singleton Met.ColorSpace Met.SRGB
+          ProfileEmbedded -> case iccProfile of
+                              Nothing -> Met.empty
+                              Just profile -> Met.singleton Met.ColorSpace
+                                                (Met.ICCProfile profile)
+          _ -> Met.empty
 
 -- | Try to decode a bitmap image.
 -- Right now this function can output the following image:
@@ -369,71 +773,134 @@ -- | Same as 'decodeBitmap' but also extracts metadata and provide separated palette.
 decodeBitmapWithPaletteAndMetadata :: B.ByteString -> Either String (PalettedImage, Metadatas)
 decodeBitmapWithPaletteAndMetadata str = flip runGetStrict str $ do
-  hdr      <- get :: Get BmpHeader
-  bmpHeader <- get :: Get BmpInfoHeader
+  fileHeader <- get :: Get BmpHeader
+  bmpHeader  <- get :: Get BmpV5Header
 
   readed <- bytesRead
-  when (readed > fromIntegral (dataOffset hdr))
+  when (readed > fromIntegral (dataOffset fileHeader))
        (fail "Invalid bmp image, data in header")
-  
+
   when (width bmpHeader <= 0)
        (fail $ "Invalid bmp width, " ++ show (width bmpHeader))
 
   when (height bmpHeader == 0)
        (fail $ "Invalid bmp height (0) ")
 
-  let bpp = fromIntegral $ bitPerPixel bmpHeader :: Int
-      paletteColorCount
-        | colorCount bmpHeader == 0 = 2 ^ bpp
-        | otherwise = fromIntegral $ colorCount bmpHeader
-      getData = do
-        readed' <- bytesRead
-        skip . fromIntegral $ dataOffset hdr - fromIntegral readed'
-        getRemainingBytes
-      addMetadata i = (i, metadataOfHeader bmpHeader)
+  decodeBitmapWithHeaders fileHeader bmpHeader
 
-  case (bitPerPixel bmpHeader, planes  bmpHeader,
-              bitmapCompression bmpHeader) of
-    (32, 1, 0) -> do
-      rest <- getData
-      return . addMetadata . TrueColorImage . ImageRGBA8 
-             $ decodeImageRGBA8 bmpHeader (2, 1, 0, 3) rest
-      -- (2, 1, 0, 3) means BGRA pixel order
-    (32, 1, 3) -> do
-      posRed   <- getBitfield
-      posGreen <- getBitfield
-      posBlue  <- getBitfield
-      posAlpha <- getBitfield
-      rest     <- getData
-      return . addMetadata . TrueColorImage . ImageRGBA8 $
-        decodeImageRGBA8 bmpHeader (posRed, posGreen, posBlue, posAlpha) rest
-    (24, 1, 0) -> do
-      rest <- getData
-      return . addMetadata . TrueColorImage . ImageRGB8  $ 
-        decodeImageRGB8  bmpHeader rest
-    ( 8, 1, 0) -> do
-      table <- replicateM paletteColorCount pixelGet
-      rest <- getData
-      let palette = Palette'
-            { _paletteSize = paletteColorCount
-            , _paletteData = VS.fromListN (paletteColorCount * 3) $ concat table
-            }
-      return . addMetadata $ PalettedRGB8 (decodeImageY8 bmpHeader rest) palette
+-- | Decode the rest of a bitmap, after the headers have been decoded.
+decodeBitmapWithHeaders :: BmpHeader -> BmpV5Header -> Get (PalettedImage, Metadatas)
+decodeBitmapWithHeaders fileHdr hdr = do
+    img <- bitmapData
+    profile <- getICCProfile
+    return $ addMetadata profile img
 
-    a          -> fail $ "Can't handle BMP file " ++ show a
+  where
+    bpp = fromIntegral $ bitPerPixel hdr :: Int
+    paletteColorCount
+      | colorCount hdr == 0 = 2 ^ bpp
+      | otherwise = fromIntegral $ colorCount hdr
 
+    addMetadata profile i = (i, metadataOfHeader hdr profile)
 
-getBitfield :: Get Int
-getBitfield = do
-  w32 <- getWord32be
-  case w32 of
-    0xFF000000 -> return 0
-    0x00FF0000 -> return 1
-    0x0000FF00 -> return 2
-    0x000000FF -> return 3
-    _          -> fail $
-      "Codec.Picture.Bitmap.getBitfield: unsupported bitfield of " ++ show w32
+    getData = do
+      readed <- bytesRead
+      label "Start of pixel data" $
+        skip . fromIntegral $ dataOffset fileHdr - fromIntegral readed
+      let pixelBytes = if bitmapCompression hdr == 1 || bitmapCompression hdr == 2
+                          then fromIntegral $ byteImageSize hdr
+                          else sizeofPixelData bpp (fromIntegral $ width hdr)
+                                                   (fromIntegral $ height hdr)
+      label "Pixel data" $ getByteString pixelBytes
 
+    getICCProfile =
+      if size hdr >= sizeofBmpV5Header
+          && colorSpaceType hdr == ProfileLinked
+          && iccProfileData hdr > 0
+          && iccProfileSize hdr > 0
+      then do
+        readSoFar <- bytesRead
+        label "Start of embedded ICC color profile" $
+          skip $ fromIntegral (iccProfileData hdr) - fromIntegral readSoFar
+        profile <- label "Embedded ICC color profile" $
+                      getByteString . fromIntegral $ iccProfileSize hdr
+        return (Just profile)
+      else return Nothing
+
+    bitmapData = case (bitPerPixel hdr, planes hdr, bitmapCompression hdr) of
+      (32, 1, 0) -> do
+        rest <- getData
+        return . TrueColorImage . ImageRGB8 $
+          decodeImageRGB8 (RGB32 defaultBitfieldsRGB32) hdr rest
+        -- (2, 1, 0, 3) means BGRA pixel order
+      (32, 1, 3) -> do
+        r <- getBitfield $ redMask hdr
+        g <- getBitfield $ greenMask hdr
+        b <- getBitfield $ blueMask hdr
+        rest     <- getData
+        if alphaMask hdr == 0
+          then return . TrueColorImage . ImageRGB8 $
+            decodeImageRGB8 (RGB32 $ Bitfields3 r g b) hdr rest
+          else do
+            a <- getBitfield $ alphaMask hdr
+            return . TrueColorImage . ImageRGBA8 $
+              decodeImageRGBA8 (RGBA32 $ Bitfields4 r g b a) hdr rest
+      (24, 1, 0) -> do
+        rest <- getData
+        return . TrueColorImage . ImageRGB8 $
+          decodeImageRGB8 RGB24 hdr rest
+      (16, 1, 0) -> do
+        rest <- getData
+        return . TrueColorImage . ImageRGB8 $
+          decodeImageRGB8 (RGB16 defaultBitfieldsRGB16) hdr rest
+      (16, 1, 3) -> do
+        r <- getBitfield . fromIntegral $ 0xFFFF .&. redMask hdr
+        g <- getBitfield . fromIntegral $ 0xFFFF .&. greenMask hdr
+        b <- getBitfield . fromIntegral $ 0xFFFF .&. blueMask hdr
+        rest     <- getData
+        if alphaMask hdr == 0
+          then return . TrueColorImage . ImageRGB8 $
+            decodeImageRGB8 (RGB16 $ Bitfields3 r g b) hdr rest
+          else do
+            a <- getBitfield . fromIntegral $ 0xFFFF .&. alphaMask hdr
+            return . TrueColorImage . ImageRGBA8 $
+              decodeImageRGBA8 (RGBA16 $ Bitfields4 r g b a) hdr rest
+      ( _, 1, compression) -> do
+        table <- if size hdr == sizeofBmpCoreHeader
+                    then replicateM paletteColorCount pixel3Get
+                    else replicateM paletteColorCount pixel4Get
+        rest <- getData
+        let palette = Palette'
+              { _paletteSize = paletteColorCount
+              , _paletteData = VS.fromListN (paletteColorCount * 3) $ concat table
+              }
+        image <-
+          case (bpp, compression) of
+            (8, 0) -> return $ decodeImageY8 EightBPP hdr rest
+            (4, 0) -> return $ decodeImageY8 FourBPP hdr rest
+            (1, 0) -> return $ decodeImageY8 OneBPP hdr rest
+            (8, 1) -> return $ decodeImageY8RLE False hdr rest
+            (4, 2) -> return $ decodeImageY8RLE True hdr rest
+            (a, b) -> fail $ "Can't handle BMP file " ++ show (a, 1 :: Int, b)
+
+        return $ PalettedRGB8 image palette
+
+      a          -> fail $ "Can't handle BMP file " ++ show a
+
+-- | Decode a bitfield. Will fail if the bitfield is empty.
+#if MIN_VERSION_base(4,13,0)
+getBitfield :: (FiniteBits t, Integral t, Num t, MonadFail m) => t -> m (Bitfield t)
+#else
+getBitfield :: (FiniteBits t, Integral t, Num t, Monad m) => t -> m (Bitfield t)
+#endif
+getBitfield 0 = fail $
+  "Codec.Picture.Bitmap.getBitfield: bitfield cannot be 0"
+getBitfield w = return (makeBitfield w)
+
+-- | Compute the size of the pixel data
+sizeofPixelData :: Int -> Int -> Int -> Int
+sizeofPixelData bpp lineWidth nLines = ((bpp * (abs lineWidth) + 31) `div` 32) * 4 * abs nLines
+
 -- | Write an image in a file use the bitmap format.
 writeBitmap :: (BmpEncodable pixel)
             => FilePath -> Image pixel -> IO ()
@@ -441,7 +908,7 @@ 
 linePadding :: Int -> Int -> Int
 linePadding bpp imgWidth = (4 - (bytesPerLine `mod` 4)) `mod` 4
-    where bytesPerLine = imgWidth * (fromIntegral bpp `div` 8)
+  where bytesPerLine = (bpp * imgWidth + 7) `div` 8
 
 -- | Encode an image into a bytestring in .bmp format ready to be written
 -- on disk.
@@ -452,7 +919,7 @@ -- the following metadatas:
 --
 --  * 'Codec.Picture.Metadata.DpiX'
---  * 'Codec.Picture.Metadata.DpiY' 
+--  * 'Codec.Picture.Metadata.DpiY'
 --
 encodeBitmapWithMetadata :: forall pixel. BmpEncodable pixel
                          => Metadatas -> Image pixel -> L.ByteString
@@ -482,8 +949,7 @@ 
 extractDpiOfMetadata :: Metadatas -> (Word32, Word32)
 extractDpiOfMetadata metas = (fetch Met.DpiX, fetch Met.DpiY) where
-  fetch k = fromMaybe 0
-          $ fromIntegral . Met.dotPerInchToDotsPerMeter <$> Met.lookup k metas
+  fetch k = maybe 0 (fromIntegral . Met.dotPerInchToDotsPerMeter) $ Met.lookup k metas
 
 -- | Convert an image to a bytestring ready to be serialized.
 encodeBitmapWithPalette :: forall pixel. (BmpEncodable pixel)
@@ -494,41 +960,76 @@ -- the following metadatas:
 --
 --  * 'Codec.Picture.Metadata.DpiX'
---  * 'Codec.Picture.Metadata.DpiY' 
+--  * 'Codec.Picture.Metadata.DpiY'
 --
 encodeBitmapWithPaletteAndMetadata :: forall pixel. (BmpEncodable pixel)
                                    => Metadatas -> BmpPalette -> Image pixel
                                    -> L.ByteString
 encodeBitmapWithPaletteAndMetadata metas pal@(BmpPalette palette) img =
   runPut $ put hdr >> put info >> putPalette pal >> bmpEncode img
+                   >> putICCProfile colorProfileData
+
     where imgWidth = fromIntegral $ imageWidth img
           imgHeight = fromIntegral $ imageHeight img
           (dpiX, dpiY) = extractDpiOfMetadata metas
+          cs = Met.lookup Met.ColorSpace metas
+          colorType = case cs of
+                        Just Met.SRGB -> SRGB
+                        Just (Met.WindowsBitmapColorSpace _) -> CalibratedRGB
+                        Just (Met.ICCProfile _) -> ProfileEmbedded
+                        Nothing -> DeviceDependentRGB
 
+          colorSpaceInfo = case cs of
+                            Just (Met.WindowsBitmapColorSpace bytes) -> bytes
+                            _ -> B.pack $ replicate sizeofColorProfile 0
+
+          colorProfileData = case cs of
+                              Just (Met.ICCProfile bytes) -> Just bytes
+                              _ -> Nothing
+
+          headerSize | colorType == ProfileEmbedded                = sizeofBmpV5Header
+                     | colorType == CalibratedRGB || hasAlpha img  = sizeofBmpV4Header
+                     | otherwise                                   = sizeofBmpInfoHeader
+
           paletteSize = fromIntegral $ length palette
           bpp = bitsPerPixel (undefined :: pixel)
-          padding = linePadding bpp imgWidth
-          imagePixelSize = fromIntegral $ (imgWidth * div bpp 8 + padding) * imgHeight
+
+          profileSize = fromIntegral $ maybe 0 B.length colorProfileData
+          imagePixelSize = fromIntegral $ sizeofPixelData bpp imgWidth imgHeight
+          offsetToData = sizeofBmpHeader + headerSize + 4 * paletteSize
+          offsetToICCProfile = offsetToData + imagePixelSize <$ colorProfileData
+          sizeOfFile = sizeofBmpHeader + headerSize + 4 * paletteSize
+                        + imagePixelSize + profileSize
+
           hdr = BmpHeader {
               magicIdentifier = bitmapMagicIdentifier,
-              fileSize = sizeofBmpHeader + sizeofBmpInfo + 4 * paletteSize + imagePixelSize,
+              fileSize = sizeOfFile,
               reserved1 = 0,
               reserved2 = 0,
-              dataOffset = sizeofBmpHeader + sizeofBmpInfo + 4 * paletteSize
+              dataOffset = offsetToData
           }
 
-          info = BmpInfoHeader {
-              size = sizeofBmpInfo,
+          info = BmpV5Header {
+              size = headerSize,
               width = fromIntegral imgWidth,
               height = fromIntegral imgHeight,
               planes = 1,
               bitPerPixel = fromIntegral bpp,
-              bitmapCompression = 0, -- no compression
+              bitmapCompression = if hasAlpha img then 3 else 0,
               byteImageSize = imagePixelSize,
               xResolution = fromIntegral dpiX,
               yResolution = fromIntegral dpiY,
-              colorCount = 0,
-              importantColours = paletteSize
+              colorCount = paletteSize,
+              importantColours = 0,
+              redMask   = if hasAlpha img then 0x00FF0000 else 0,
+              greenMask = if hasAlpha img then 0x0000FF00 else 0,
+              blueMask  = if hasAlpha img then 0x000000FF else 0,
+              alphaMask = if hasAlpha img then 0xFF000000 else 0,
+              colorSpaceType = colorType,
+              colorSpace = colorSpaceInfo,
+              iccIntent = 0,
+              iccProfileData = fromMaybe 0 offsetToICCProfile,
+              iccProfileSize = profileSize
           }
 
 
src/Codec/Picture/ColorQuant.hs view
@@ -10,6 +10,7 @@ -- with its palette.
 module Codec.Picture.ColorQuant
     ( palettize
+    , palettizeWithAlpha
     , defaultPaletteOptions
     , PaletteCreationMethod(..)
     , PaletteOptions( .. )
@@ -32,6 +33,7 @@ import qualified Data.Vector.Storable as VS
 
 import           Codec.Picture.Types
+import           Codec.Picture.Gif (GifFrame(..), GifDisposalMethod, GifDelay)
 
 -------------------------------------------------------------------------------
 ----            Palette Creation and Dithering
@@ -71,7 +73,54 @@     , paletteColorCount     = 256
     }
 
--- | Reduces an image to a color palette according to `PaletteOpts` and
+-- | Changes all pixels with alpha = 0 to black
+-- converting image to RGB (from RGBA) in meantime
+alphaToBlack :: Image PixelRGBA8 -> Image PixelRGB8
+alphaToBlack = pixelMap f
+  where f (PixelRGBA8 r g b a) =
+          if a == 0 then PixelRGB8 0 0 0
+          else PixelRGB8 r g b
+
+-- | Using second image as a stencil, changes palette index to the transparent
+alphaTo255 :: Image Pixel8 -> Image PixelRGBA8 -> Pixel8 -> Image Pixel8
+alphaTo255 img1 img2 transparentIndex = generateImage f (imageWidth img1) (imageHeight img2)
+  where f x y =
+          if a == 0 then transparentIndex
+          else v
+          where v = pixelAt img1 x y
+                PixelRGBA8 _ _ _ a = pixelAt img2 x y
+
+-- | Converts RGBA image to the array of GifFame's to use in encodeComplexGifImage
+palettizeWithAlpha :: [(GifDelay, Image PixelRGBA8)] -> GifDisposalMethod -> [GifFrame]
+palettizeWithAlpha [] _ = []
+palettizeWithAlpha (x:xs) dispose =
+  GifFrame
+    0 -- Offset X
+    0 -- Offset Y 
+    (Just $ palet)
+    (Just $ transparentIndex)
+    delay
+    dispose
+    (alphaTo255 pixels i (fromIntegral transparentIndex))
+  : palettizeWithAlpha xs dispose
+  where (delay, i) = x
+        img = alphaToBlack i
+        (palet, pixels) =
+          if isBelow
+            then (vecToPalette (belowPaletteVec `V.snoc` PixelRGB8 0 0 0), pixelMap belowPaletteIndex img)
+            else (vecToPalette (genPaletteVec   `V.snoc` PixelRGB8 0 0 0), pixelMap genPaletteIndex img)
+
+        (belowPalette, isBelow) = isColorCountBelow 255 img
+        belowPaletteVec = V.fromList $ Set.toList belowPalette
+        belowPaletteIndex p = nearestColorIdx p belowPaletteVec
+
+        cs = Set.toList . clusters 255 $ img
+        genPaletteVec = mkPaletteVec cs
+        genPaletteIndex p = nearestColorIdx p genPaletteVec
+
+        transparentIndex = length $ if isBelow then belowPaletteVec else genPaletteVec
+
+-- | Reduces an image to a color palette according to `PaletteOptions` and
 --   returns the /indices image/ along with its `Palette`.
 palettize :: PaletteOptions -> Image PixelRGB8 -> (Image Pixel8, Palette)
 palettize opts@PaletteOptions { paletteCreationMethod = method } =
@@ -100,7 +149,7 @@     cs =  Set.toList . clusters maxColorCount $ img
     dImg = pixelMapXY dither img
 
--- | A naive one pass Color Quantiation algorithm - Uniform Quantization.
+-- | A naive one pass Color Quantization algorithm - Uniform Quantization.
 -- Simply take the most significant bits. The maxCols parameter is rounded
 -- down to the nearest power of 2, and the bits are divided among the three
 -- color channels with priority order green, red, blue. Returns an
@@ -120,7 +169,7 @@     (bg, br, bb) = bitDiv3 maxCols
     (dr, dg, db) = (2^(8-br), 2^(8-bg), 2^(8-bb))
     paletteIndex (PixelRGB8 r g b) = fromIntegral $ fromMaybe 0 (elemIndex
-      (PixelRGB8 (r .&. (256 - dr)) (g .&. (256 - dg)) (b .&. (256 - db)))
+      (PixelRGB8 (r .&. negate dr) (g .&. negate dg) (b .&. negate db))
       paletteList)
 
 isColorCountBelow :: Int -> Image PixelRGB8 -> (Set.Set PixelRGB8, Bool)
@@ -229,7 +278,7 @@ 
 -- Based on the OCaml implementation:
 -- http://rosettacode.org/wiki/Color_quantization
--- which is in turn based on: www.leptonica.com/papers/mediancut.pdf.
+-- which is in turn based on: www.leptonica.org/papers/mediancut.pdf.
 -- We use the product of volume and population to determine the next cluster
 -- to split and determine the placement of each color by compating it to the
 -- mean of the parent cluster. So median cut is a bit of a misnomer, since one
src/Codec/Picture/Gif.hs view
@@ -1,859 +1,1006 @@-{-# LANGUAGE TypeFamilies #-}-{-# LANGUAGE FlexibleContexts #-}-{-# LANGUAGE ScopedTypeVariables #-}-{-# LANGUAGE CPP #-}--- | Module implementing GIF decoding.-module Codec.Picture.Gif ( -- * Reading-                           decodeGif-                         , decodeGifWithMetadata-                         , decodeGifWithPaletteAndMetadata-                         , decodeGifImages-                         , getDelaysGifImages--                           -- * Writing-                         , GifDelay-                         , GifLooping( .. )-                         , encodeGifImage-                         , encodeGifImageWithPalette-                         , encodeGifImages--                         , writeGifImage-                         , writeGifImageWithPalette-                         , writeGifImages-                         , greyPalette-                         ) where--#if !MIN_VERSION_base(4,8,0)-import Control.Applicative( pure, (<*>), (<$>) )-#endif--import Control.Arrow( first )-import Control.Monad( replicateM, replicateM_, unless )-import Control.Monad.ST( runST )-import Control.Monad.Trans.Class( lift )--import Data.Bits( (.&.), (.|.)-                , unsafeShiftR-                , unsafeShiftL-                , testBit, setBit )-import Data.Word( Word8, Word16 )--import qualified Data.ByteString as B-import qualified Data.ByteString.Char8 as BC-import qualified Data.ByteString.Lazy as L-import qualified Data.Vector.Storable as V-import qualified Data.Vector.Storable.Mutable as M--import Data.Binary( Binary(..), encode )-import Data.Binary.Get( Get-                      , getWord8-                      , getWord16le-                      , getByteString-                      , bytesRead-                      , skip-                      )--import Data.Binary.Put( Put-                      , putWord8-                      , putWord16le-                      , putByteString-                      )--import Codec.Picture.InternalHelper-import Codec.Picture.Types-import Codec.Picture.Metadata( Metadatas-                             , SourceFormat( SourceGif )-                             , basicMetadata )-import Codec.Picture.Gif.LZW-import Codec.Picture.Gif.LZWEncoding-import Codec.Picture.BitWriter---- | Delay to wait before showing the next Gif image.--- The delay is expressed in 100th of seconds.-type GifDelay = Int---- | Help to control the behaviour of GIF animation looping.-data GifLooping =-      -- | The animation will stop once the end is reached-      LoopingNever-      -- | The animation will restart once the end is reached-    | LoopingForever-      -- | The animation will repeat n times before stoping-    | LoopingRepeat Word16--{--   <GIF Data Stream> ::=     Header <Logical Screen> <Data>* Trailer--   <Logical Screen> ::=      Logical Screen Descriptor [Global Color Table]--   <Data> ::=                <Graphic Block>  |-                             <Special-Purpose Block>--   <Graphic Block> ::=       [Graphic Control Extension] <Graphic-Rendering Block>--   <Graphic-Rendering Block> ::=  <Table-Based Image>  |-                                  Plain Text Extension--   <Table-Based Image> ::=   Image Descriptor [Local Color Table] Image Data--   <Special-Purpose Block> ::=    Application Extension  |-                                  Comment Extension- -}---------------------------------------------------------            GifVersion----------------------------------------------------data GifVersion = GIF87a | GIF89a--gif87aSignature, gif89aSignature :: B.ByteString-gif87aSignature = B.pack $ map (fromIntegral . fromEnum) "GIF87a"-gif89aSignature = B.pack $ map (fromIntegral . fromEnum) "GIF89a"--instance Binary GifVersion where-    put GIF87a = putByteString gif87aSignature-    put GIF89a = putByteString gif89aSignature--    get = do-        sig <- getByteString (B.length gif87aSignature)-        case (sig == gif87aSignature, sig == gif89aSignature) of-            (True, _)  -> pure GIF87a-            (_ , True) -> pure GIF89a-            _          -> fail $ "Invalid Gif signature : " ++ (toEnum . fromEnum <$> B.unpack sig)----------------------------------------------------------         LogicalScreenDescriptor------------------------------------------------------ | Section 18 of spec-gif89a-data LogicalScreenDescriptor = LogicalScreenDescriptor-  { -- | Stored on 16 bits-    screenWidth           :: !Word16-    -- | Stored on 16 bits-  , screenHeight          :: !Word16-    -- | Stored on 8 bits-  , backgroundIndex       :: !Word8--  -- | Stored on 1 bit-  , hasGlobalMap          :: !Bool-  -- | Stored on 3 bits-  , colorResolution       :: !Word8-  -- | Stored on 1 bit-  , isColorTableSorted    :: !Bool-  -- | Stored on 3 bits-  , colorTableSize        :: !Word8-  }--instance Binary LogicalScreenDescriptor where-    put v = do-      putWord16le $ screenWidth v-      putWord16le $ screenHeight v-      let globalMapField-            | hasGlobalMap v = 0x80-            | otherwise = 0--          colorTableSortedField-            | isColorTableSorted v = 0x08-            | otherwise = 0--          tableSizeField = (colorTableSize v - 1) .&. 7--          colorResolutionField =-            ((colorResolution v - 1) .&. 7) `unsafeShiftL` 5--          packedField = globalMapField-                     .|. colorTableSortedField-                     .|. tableSizeField-                     .|. colorResolutionField--      putWord8 packedField-      putWord8 0 -- aspect ratio-      putWord8 $ backgroundIndex v--    get = do-        w <- getWord16le-        h <- getWord16le-        packedField  <- getWord8-        backgroundColorIndex  <- getWord8-        _aspectRatio  <- getWord8-        return LogicalScreenDescriptor-            { screenWidth           = w-            , screenHeight          = h-            , hasGlobalMap          = packedField `testBit` 7-            , colorResolution       = (packedField `unsafeShiftR` 5) .&. 0x7 + 1-            , isColorTableSorted    = packedField `testBit` 3-            , colorTableSize        = (packedField .&. 0x7) + 1-            , backgroundIndex       = backgroundColorIndex-            }----------------------------------------------------------            ImageDescriptor------------------------------------------------------ | Section 20 of spec-gif89a-data ImageDescriptor = ImageDescriptor-  { gDescPixelsFromLeft         :: !Word16-  , gDescPixelsFromTop          :: !Word16-  , gDescImageWidth             :: !Word16-  , gDescImageHeight            :: !Word16-  , gDescHasLocalMap            :: !Bool-  , gDescIsInterlaced           :: !Bool-  , gDescIsImgDescriptorSorted  :: !Bool-  , gDescLocalColorTableSize    :: !Word8-  }--imageSeparator, extensionIntroducer, gifTrailer :: Word8-imageSeparator      = 0x2C-extensionIntroducer = 0x21-gifTrailer          = 0x3B--graphicControlLabel, commentLabel, plainTextLabel, applicationLabel :: Word8-plainTextLabel = 0x01-graphicControlLabel = 0xF9-commentLabel = 0xFE-applicationLabel    = 0xFF---parseDataBlocks :: Get B.ByteString-parseDataBlocks = B.concat <$> (getWord8 >>= aux)- where aux    0 = pure []-       aux size = (:) <$> getByteString (fromIntegral size) <*> (getWord8 >>= aux)--putDataBlocks :: B.ByteString -> Put-putDataBlocks wholeString = putSlices wholeString >> putWord8 0-  where putSlices str | B.length str == 0 = pure ()-                      | B.length str > 0xFF =-            let (before, after) = B.splitAt 0xFF str in-            putWord8 0xFF >> putByteString before >> putSlices after-        putSlices str =-            putWord8 (fromIntegral $ B.length str) >> putByteString str--data DisposalMethod-    = DisposalAny-    | DisposalDoNot-    | DisposalRestoreBackground-    | DisposalRestorePrevious-    | DisposalUnknown Word8--disposalMethodOfCode :: Word8 -> DisposalMethod-disposalMethodOfCode v = case v of-    0 -> DisposalAny-    1 -> DisposalDoNot-    2 -> DisposalRestoreBackground-    3 -> DisposalRestorePrevious-    n -> DisposalUnknown n--codeOfDisposalMethod :: DisposalMethod -> Word8-codeOfDisposalMethod v = case v of-    DisposalAny -> 0-    DisposalDoNot -> 1-    DisposalRestoreBackground -> 2-    DisposalRestorePrevious -> 3-    DisposalUnknown n -> n--data GraphicControlExtension = GraphicControlExtension-    { gceDisposalMethod        :: !DisposalMethod -- ^ Stored on 3 bits-    , gceUserInputFlag         :: !Bool-    , gceTransparentFlag       :: !Bool-    , gceDelay                 :: !Word16-    , gceTransparentColorIndex :: !Word8-    }--instance Binary GraphicControlExtension where-    put v = do-        putWord8 extensionIntroducer-        putWord8 graphicControlLabel-        putWord8 0x4  -- size-        let disposalCode = codeOfDisposalMethod $ gceDisposalMethod v-            disposalField =-                (disposalCode .&. 0x7) `unsafeShiftL` 2--            userInputField-                | gceUserInputFlag v = 0 `setBit` 1-                | otherwise = 0--            transparentField-                | gceTransparentFlag v = 0 `setBit` 0-                | otherwise = 0--            packedFields =  disposalField-                        .|. userInputField-                        .|. transparentField--        putWord8 packedFields-        putWord16le $ gceDelay v-        putWord8 $ gceTransparentColorIndex v-        putWord8 0 -- blockTerminator--    get = do-        -- due to missing lookahead-        {-_extensionLabel  <- getWord8-}-        _size            <- getWord8-        packedFields     <- getWord8-        delay            <- getWord16le-        idx              <- getWord8-        _blockTerminator <- getWord8-        return GraphicControlExtension-            { gceDisposalMethod        = -                disposalMethodOfCode $-                    (packedFields `unsafeShiftR` 2) .&. 0x07-            , gceUserInputFlag         = packedFields `testBit` 1-            , gceTransparentFlag       = packedFields `testBit` 0-            , gceDelay                 = delay-            , gceTransparentColorIndex = idx-            }--data GifImage = GifImage-    { imgDescriptor   :: !ImageDescriptor-    , imgLocalPalette :: !(Maybe Palette)-    , imgLzwRootSize  :: !Word8-    , imgData         :: B.ByteString-    }--instance Binary GifImage where-    put img = do-        let descriptor = imgDescriptor img-        put descriptor-        case ( imgLocalPalette img-             , gDescHasLocalMap $ imgDescriptor img) of-          (Nothing, _) -> return ()-          (Just _, False) -> return ()-          (Just p, True) ->-              putPalette (fromIntegral $ gDescLocalColorTableSize descriptor) p-        putWord8 $ imgLzwRootSize img-        putDataBlocks $ imgData img--    get = do-        desc <- get-        let hasLocalColorTable = gDescHasLocalMap desc-        palette <- if hasLocalColorTable-           then Just <$> getPalette (gDescLocalColorTableSize desc)-           else pure Nothing--        GifImage desc palette <$> getWord8 <*> parseDataBlocks--data Block = BlockImage GifImage-           | BlockGraphicControl GraphicControlExtension--skipSubDataBlocks :: Get ()-skipSubDataBlocks = do-  s <- fromIntegral <$> getWord8-  unless (s == 0) $-    skip s >> skipSubDataBlocks--parseGifBlocks :: Get [Block]-parseGifBlocks = getWord8 >>= blockParse-  where-    blockParse v-      | v == gifTrailer = pure []-      | v == imageSeparator = (:) <$> (BlockImage <$> get) <*> parseGifBlocks-      | v == extensionIntroducer = getWord8 >>= extensionParse--    blockParse v = do-      readPosition <- bytesRead-      fail ("Unrecognized gif block " ++ show v ++ " @" ++ show readPosition)--    extensionParse code-     | code == graphicControlLabel =-        (:) <$> (BlockGraphicControl <$> get) <*> parseGifBlocks-     | code == commentLabel = skipSubDataBlocks >> parseGifBlocks-     | code `elem` [plainTextLabel, applicationLabel] =-        fromIntegral <$> getWord8 >>= skip >> skipSubDataBlocks >> parseGifBlocks-     | otherwise = parseDataBlocks >> parseGifBlocks---instance Binary ImageDescriptor where-    put v = do-        putWord8 imageSeparator-        putWord16le $ gDescPixelsFromLeft v-        putWord16le $ gDescPixelsFromTop v-        putWord16le $ gDescImageWidth v-        putWord16le $ gDescImageHeight v-        let localMapField-                | gDescHasLocalMap v = 0 `setBit` 7-                | otherwise = 0--            isInterlacedField-                | gDescIsInterlaced v = 0 `setBit` 6-                | otherwise = 0--            isImageDescriptorSorted-                | gDescIsImgDescriptorSorted v = 0 `setBit` 5-                | otherwise = 0--            localSize = gDescLocalColorTableSize v-            tableSizeField-                | localSize > 0 = (localSize - 1) .&. 0x7-                | otherwise = 0--            packedFields = localMapField-                        .|. isInterlacedField-                        .|. isImageDescriptorSorted-                        .|. tableSizeField-        putWord8 packedFields--    get = do-        -- due to missing lookahead-        {-_imageSeparator <- getWord8-}-        imgLeftPos <- getWord16le-        imgTopPos  <- getWord16le-        imgWidth   <- getWord16le-        imgHeight  <- getWord16le-        packedFields <- getWord8-        let tableSize = packedFields .&. 0x7-        return ImageDescriptor-            { gDescPixelsFromLeft = imgLeftPos-            , gDescPixelsFromTop  = imgTopPos-            , gDescImageWidth     = imgWidth-            , gDescImageHeight    = imgHeight-            , gDescHasLocalMap    = packedFields `testBit` 7-            , gDescIsInterlaced     = packedFields `testBit` 6-            , gDescIsImgDescriptorSorted = packedFields `testBit` 5-            , gDescLocalColorTableSize = if tableSize > 0 then tableSize + 1 else 0-            }----------------------------------------------------------            Palette----------------------------------------------------getPalette :: Word8 -> Get Palette-getPalette bitDepth = -    Image size 1 . V.fromList <$> replicateM (size * 3) get-  where size = 2 ^ (fromIntegral bitDepth :: Int)--putPalette :: Int -> Palette -> Put-putPalette size pal = do-    V.mapM_ putWord8 (imageData pal)-    replicateM_ missingColorComponent (putWord8 0)-  where elemCount = 2 ^ size-        missingColorComponent = (elemCount - imageWidth pal) * 3---------------------------------------------------------            GifImage----------------------------------------------------data GifHeader = GifHeader-  { gifVersion          :: GifVersion-  , gifScreenDescriptor :: LogicalScreenDescriptor-  , gifGlobalMap        :: !Palette-  }--instance Binary GifHeader where-    put v = do-      put $ gifVersion v-      let descr = gifScreenDescriptor v-      put descr-      putPalette (fromIntegral $ colorTableSize descr) $ gifGlobalMap v--    get = do-        version    <- get-        screenDesc <- get-        -        palette <- -          if hasGlobalMap screenDesc then-            getPalette $ colorTableSize screenDesc-          else-            return greyPalette--        return GifHeader-            { gifVersion = version-            , gifScreenDescriptor = screenDesc-            , gifGlobalMap = palette-            }--data GifFile = GifFile-    { gifHeader      :: !GifHeader-    , gifImages      :: [(Maybe GraphicControlExtension, GifImage)]-    , gifLoopingBehaviour :: GifLooping-    }--putLooping :: GifLooping -> Put-putLooping LoopingNever = return ()-putLooping LoopingForever = putLooping $ LoopingRepeat 0-putLooping (LoopingRepeat count) = do-    putWord8 extensionIntroducer-    putWord8 applicationLabel-    putWord8 11 -- the size-    putByteString $ BC.pack "NETSCAPE2.0"-    putWord8 3 -- size of sub block-    putWord8 1-    putWord16le count-    putWord8 0--associateDescr :: [Block] -> [(Maybe GraphicControlExtension, GifImage)]-associateDescr [] = []-associateDescr [BlockGraphicControl _] = []-associateDescr (BlockGraphicControl _ : rest@(BlockGraphicControl _ : _)) =-    associateDescr rest-associateDescr (BlockImage img:xs) = (Nothing, img) : associateDescr xs-associateDescr (BlockGraphicControl ctrl : BlockImage img : xs) =-    (Just ctrl, img) : associateDescr xs--instance Binary GifFile where-    put v = do-        put $ gifHeader v-        let putter (Nothing, i) = put i-            putter (Just a, i) = put a >> put i-        putLooping $ gifLoopingBehaviour v-        mapM_ putter $ gifImages v-        put gifTrailer--    get = do-        hdr <- get-        blocks <- parseGifBlocks-        return GifFile { gifHeader = hdr-                       , gifImages = associateDescr blocks-                       , gifLoopingBehaviour = LoopingNever-                       }--substituteColors :: Palette -> Image Pixel8 -> Image PixelRGB8-substituteColors palette = pixelMap swaper-  where swaper n = pixelAt palette (fromIntegral n) 0--substituteColorsWithTransparency :: Int -> Image PixelRGBA8 -> Image Pixel8 -> Image PixelRGBA8-substituteColorsWithTransparency transparent palette = pixelMap swaper where-  swaper n | ix == transparent = PixelRGBA8 0 0 0 0-           | otherwise = promotePixel $ pixelAt palette ix 0-    where ix = fromIntegral n---decodeImage :: GifImage -> Image Pixel8-decodeImage img = runST $ runBoolReader $ do-    outputVector <- lift . M.new $ width * height-    decodeLzw (imgData img) 12 lzwRoot outputVector-    frozenData <- lift $ V.unsafeFreeze outputVector-    return . deinterlaceGif $ Image-      { imageWidth = width-      , imageHeight = height-      , imageData = frozenData-      }-  where lzwRoot = fromIntegral $ imgLzwRootSize img-        width = fromIntegral $ gDescImageWidth descriptor-        height = fromIntegral $ gDescImageHeight descriptor-        isInterlaced = gDescIsInterlaced descriptor-        descriptor = imgDescriptor img--        deinterlaceGif | not isInterlaced = id-                       | otherwise = deinterlaceGifImage--deinterlaceGifImage :: Image Pixel8 -> Image Pixel8-deinterlaceGifImage img@(Image { imageWidth = w, imageHeight = h }) = generateImage generator w h-   where lineIndices = gifInterlacingIndices h-         generator x y = pixelAt img x y'-            where y' = lineIndices V.! y--gifInterlacingIndices :: Int -> V.Vector Int-gifInterlacingIndices height = V.accum (\_ v -> v) (V.replicate height 0) indices-    where indices = flip zip [0..] $-                concat [ [0,     8 .. height - 1]-                       , [4, 4 + 8 .. height - 1]-                       , [2, 2 + 4 .. height - 1]-                       , [1, 1 + 2 .. height - 1]-                       ]--paletteOf :: (ColorConvertible PixelRGB8 px)-          => Image px -> GifImage -> Image px-paletteOf global GifImage { imgLocalPalette = Nothing } = global-paletteOf      _ GifImage { imgLocalPalette = Just p  } = promoteImage p--getFrameDelays :: GifFile -> [GifDelay]-getFrameDelays GifFile { gifImages = [] } = []-getFrameDelays GifFile { gifImages = imgs } = map extractDelay imgs-    where extractDelay (ext, _) =-            case ext of-                Nothing -> 0-                Just e -> fromIntegral $ gceDelay e--transparentColorOf :: Maybe GraphicControlExtension -> Int-transparentColorOf Nothing = 300-transparentColorOf (Just ext)-  | gceTransparentFlag ext = fromIntegral $ gceTransparentColorIndex ext-  | otherwise = 300--hasTransparency :: Maybe GraphicControlExtension -> Bool-hasTransparency Nothing = False-hasTransparency (Just control) = gceTransparentFlag control--decodeAllGifImages :: GifFile -> [PalettedImage]-decodeAllGifImages GifFile { gifImages = [] } = []-decodeAllGifImages GifFile { gifHeader = GifHeader { gifGlobalMap = palette-                                                   , gifScreenDescriptor = wholeDescriptor }-                           , gifImages = (firstControl, firstImage) : rest }-  | not (hasTransparency firstControl) =-      let backImage =-              generateImage (\_ _ -> backgroundColor) globalWidth globalHeight-          thisPalette = paletteOf palette firstImage-          baseImage = decodeImage firstImage-          initState =-            (thisPalette, firstControl, substituteColors thisPalette baseImage)-          scanner = gifAnimationApplyer (globalWidth, globalHeight) thisPalette backImage-          palette' = Palette'-            { _paletteSize = imageWidth thisPalette-            , _paletteData = imageData thisPalette-            }-      in-      PalettedRGB8 baseImage palette' :-        [TrueColorImage $ ImageRGB8 img | (_, _, img) <- tail $ scanl scanner initState rest]--  | otherwise =-      let backImage :: Image PixelRGBA8-          backImage =-            generateImage (\_ _ -> transparentBackground) globalWidth globalHeight--          thisPalette :: Image PixelRGBA8-          thisPalette = paletteOf (promoteImage palette) firstImage--          transparentCode = transparentColorOf firstControl-          decoded = -            substituteColorsWithTransparency transparentCode thisPalette $-                decodeImage firstImage--          initState = (thisPalette, firstControl, decoded)-          scanner =-            gifAnimationApplyer (globalWidth, globalHeight) thisPalette backImage in-      [TrueColorImage $ ImageRGBA8 img | (_, _, img) <- scanl scanner initState rest]--    where -      globalWidth = fromIntegral $ screenWidth wholeDescriptor-      globalHeight = fromIntegral $ screenHeight wholeDescriptor--      transparentBackground = PixelRGBA8 r g b 0-          where PixelRGB8 r g b = backgroundColor--      backgroundColor-        | hasGlobalMap wholeDescriptor =-            pixelAt palette (fromIntegral $ backgroundIndex wholeDescriptor) 0-        | otherwise = PixelRGB8 0 0 0--gifAnimationApplyer :: forall px.  (ColorConvertible PixelRGB8 px)-                    => (Int, Int) -> Image px -> Image px-                    -> (Image px, Maybe GraphicControlExtension, Image px)-                    -> (Maybe GraphicControlExtension, GifImage)-                    -> (Image px, Maybe GraphicControlExtension, Image px)-gifAnimationApplyer (globalWidth, globalHeight) globalPalette backgroundImage-          (_, prevControl, img1)-          (controlExt, img2@(GifImage { imgDescriptor = descriptor })) =-            (thisPalette, controlExt, thisImage)-  where-    thisPalette :: Image px-    thisPalette = paletteOf globalPalette img2--    thisImage = generateImage pixeler globalWidth globalHeight-    localWidth = fromIntegral $ gDescImageWidth descriptor-    localHeight = fromIntegral $ gDescImageHeight descriptor--    left = fromIntegral $ gDescPixelsFromLeft descriptor-    top = fromIntegral $ gDescPixelsFromTop descriptor--    isPixelInLocalImage x y =-        x >= left && x < left + localWidth && y >= top && y < top + localHeight--    decoded :: Image Pixel8-    decoded = decodeImage img2--    transparent :: Int-    transparent = case controlExt of-        Nothing  -> 300-        Just ext -> if gceTransparentFlag ext-            then fromIntegral $ gceTransparentColorIndex ext-            else 300--    oldImage = case gceDisposalMethod <$> prevControl of-        Nothing -> img1-        Just DisposalAny -> img1-        Just DisposalDoNot -> img1-        Just DisposalRestoreBackground -> backgroundImage-        Just DisposalRestorePrevious -> img1-        Just (DisposalUnknown _) -> img1--    pixeler x y-      | isPixelInLocalImage x y && code /= transparent = val where-          code = fromIntegral $ pixelAt decoded (x - left) (y - top)-          val = pixelAt thisPalette (fromIntegral code) 0-    pixeler x y = pixelAt oldImage x y--decodeFirstGifImage :: GifFile -> Either String (PalettedImage, Metadatas)-decodeFirstGifImage img@GifFile { gifImages = (firstImage:_) } =-    case decodeAllGifImages img { gifImages = [firstImage] } of-      [] -> Left "No image after decoding"-      (i:_) -> Right (i, basicMetadata SourceGif (screenWidth hdr) (screenHeight hdr))-  where hdr = gifScreenDescriptor $ gifHeader img-decodeFirstGifImage _ = Left "No image in gif file"---- | Transform a raw gif image to an image, without modifying the pixels. This--- function can output the following images:------  * 'ImageRGB8'------  * 'ImageRGBA8'----decodeGif :: B.ByteString -> Either String DynamicImage-decodeGif img = decode img >>= (fmap (palettedToTrueColor . fst) . decodeFirstGifImage)---- | Transform a raw gif image to an image, without modifying the pixels.  This--- function can output the following images:------  * 'ImageRGB8'------  * 'ImageRGBA8'------ Metadatas include Width & Height information.----decodeGifWithMetadata :: B.ByteString -> Either String (DynamicImage, Metadatas)-decodeGifWithMetadata img = first palettedToTrueColor <$> decodeGifWithPaletteAndMetadata img---- | Return the gif image with metadata and palette.--- The palette is only returned for the first image of an--- animation and has no transparency.-decodeGifWithPaletteAndMetadata :: B.ByteString -> Either String (PalettedImage, Metadatas)-decodeGifWithPaletteAndMetadata img = decode img >>= decodeFirstGifImage---- | Transform a raw gif to a list of images, representing--- all the images of an animation.-decodeGifImages :: B.ByteString -> Either String [DynamicImage]-decodeGifImages img = fmap palettedToTrueColor . decodeAllGifImages <$> decode img---- | Extract a list of frame delays from a raw gif.-getDelaysGifImages :: B.ByteString -> Either String [GifDelay]-getDelaysGifImages img = getFrameDelays <$> decode img---- | Default palette to produce greyscale images.-greyPalette :: Palette-greyPalette = generateImage toGrey 256 1-  where toGrey x _ = PixelRGB8 ix ix ix-           where ix = fromIntegral x--checkGifImageSizes :: [(a, b, Image px)] -> Bool-checkGifImageSizes [] = False-checkGifImageSizes ((_, _, img) : rest) = all checkDimension rest-   where width = imageWidth img-         height = imageHeight img--         checkDimension (_,_,Image { imageWidth = w, imageHeight = h }) =-             w == width && h == height--checkPaletteValidity :: [(Palette, a, b)] -> Bool-checkPaletteValidity [] = False-checkPaletteValidity lst =-    and [h == 1 && w > 0 && w <= 256 | (p, _, _) <- lst-                                     , let w = imageWidth p-                                           h = imageHeight p ]--areIndexAbsentFromPalette :: (Palette, a, Image Pixel8) -> Bool-areIndexAbsentFromPalette (palette, _, img) = V.any isTooBig $ imageData img-  where paletteElemCount = imageWidth palette-        isTooBig v = fromIntegral v >= paletteElemCount--computeMinimumLzwKeySize :: Palette -> Int-computeMinimumLzwKeySize Image { imageWidth = itemCount } = go 2-  where go k | 2 ^ k >= itemCount = k-             | otherwise = go $ k + 1---- | Encode a gif animation to a bytestring.------ * Every image must have the same size------ * Every palette must have between one and 256 colors.----encodeGifImages :: GifLooping -> [(Palette, GifDelay, Image Pixel8)]-                -> Either String L.ByteString-encodeGifImages _ [] = Left "No image in list"-encodeGifImages _ imageList-    | not $ checkGifImageSizes imageList = Left "Gif images have different size"-    | not $ checkPaletteValidity imageList =-        Left $ "Invalid palette size " ++ concat [show (imageWidth pal) ++ " "| (pal, _, _) <- imageList ]-    | any areIndexAbsentFromPalette imageList = Left "Image contains indexes absent from the palette"-encodeGifImages looping imageList@((firstPalette, _,firstImage):_) = Right $ encode allFile-  where-    version = case imageList of-      [] -> GIF87a-      [_] -> GIF87a-      _:_:_ -> GIF89a--    allFile = GifFile-        { gifHeader = GifHeader-            { gifVersion = version-            , gifScreenDescriptor = logicalScreen-            , gifGlobalMap = firstPalette-            }-        , gifImages = toSerialize-        , gifLoopingBehaviour = looping-        }--    logicalScreen = LogicalScreenDescriptor-        { screenWidth        = fromIntegral $ imageWidth firstImage-        , screenHeight       = fromIntegral $ imageHeight firstImage-        , backgroundIndex    = 0-        , hasGlobalMap       = True-        , colorResolution    = 8-        , isColorTableSorted = False-        , colorTableSize     = 8-        }--    paletteEqual p = imageData firstPalette == imageData p--    controlExtension 0 =  Nothing-    controlExtension delay = Just GraphicControlExtension-        { gceDisposalMethod        = DisposalAny-        , gceUserInputFlag         = False-        , gceTransparentFlag       = False-        , gceDelay                 = fromIntegral delay-        , gceTransparentColorIndex = 0-        }--    toSerialize = [(controlExtension delay, GifImage-        { imgDescriptor = imageDescriptor lzwKeySize (paletteEqual palette) img-        , imgLocalPalette = Just palette-        , imgLzwRootSize = fromIntegral lzwKeySize-        , imgData = B.concat . L.toChunks . lzwEncode lzwKeySize $ imageData img-        }) | (palette, delay, img) <- imageList-           , let lzwKeySize = computeMinimumLzwKeySize palette-           ]--    imageDescriptor paletteSize palEqual img = ImageDescriptor-        { gDescPixelsFromLeft         = 0-        , gDescPixelsFromTop          = 0-        , gDescImageWidth             = fromIntegral $ imageWidth img-        , gDescImageHeight            = fromIntegral $ imageHeight img-        , gDescHasLocalMap            = paletteSize > 0 && not palEqual-        , gDescIsInterlaced           = False-        , gDescIsImgDescriptorSorted  = False-        , gDescLocalColorTableSize    = if palEqual then 0 else fromIntegral paletteSize-        }---- | Encode a greyscale image to a bytestring.-encodeGifImage :: Image Pixel8 -> L.ByteString-encodeGifImage img = case encodeGifImages LoopingNever [(greyPalette, 0, img)] of-    Left err -> error $ "Impossible:" ++ err-    Right v -> v---- | Encode an image with a given palette.--- Can return errors if the palette is ill-formed.------ * A palette must have between 1 and 256 colors----encodeGifImageWithPalette :: Image Pixel8 -> Palette -> Either String L.ByteString-encodeGifImageWithPalette img palette =-    encodeGifImages LoopingNever [(palette, 0, img)]---- | Write a greyscale in a gif file on the disk.-writeGifImage :: FilePath -> Image Pixel8 -> IO ()-writeGifImage file = L.writeFile file . encodeGifImage---- | Write a list of images as a gif animation in a file.------ * Every image must have the same size------ * Every palette must have between one and 256 colors.----writeGifImages :: FilePath -> GifLooping -> [(Palette, GifDelay, Image Pixel8)]-               -> Either String (IO ())-writeGifImages file looping lst = L.writeFile file <$> encodeGifImages looping lst---- | Write a gif image with a palette to a file.------ * A palette must have between 1 and 256 colors----writeGifImageWithPalette :: FilePath -> Image Pixel8 -> Palette-                         -> Either String (IO ())-writeGifImageWithPalette file img palette =-    L.writeFile file <$> encodeGifImageWithPalette img palette-+{-# LANGUAGE TypeFamilies #-}
+{-# LANGUAGE FlexibleContexts #-}
+{-# LANGUAGE ScopedTypeVariables #-}
+{-# LANGUAGE CPP #-}
+-- | Module implementing GIF decoding.
+module Codec.Picture.Gif ( -- * Reading
+                           decodeGif
+                         , decodeGifWithMetadata
+                         , decodeGifWithPaletteAndMetadata
+                         , decodeGifImages
+                         , getDelaysGifImages
+
+                           -- * Writing
+                         , GifDelay
+                         , GifDisposalMethod( .. )
+                         , GifEncode( .. )
+                         , GifFrame( .. )
+                         , GifLooping( .. )
+                         , encodeGifImage
+                         , encodeGifImageWithPalette
+                         , encodeGifImages
+                         , encodeComplexGifImage
+
+                         , writeGifImage
+                         , writeGifImageWithPalette
+                         , writeGifImages
+                         , writeComplexGifImage
+                         , greyPalette
+                         ) where
+
+#if !MIN_VERSION_base(4,8,0)
+import Control.Applicative( pure, (<*>), (<$>) )
+#endif
+
+import Control.Arrow( first )
+import Control.Monad( replicateM, replicateM_, unless, when )
+import Control.Monad.ST( runST )
+import Control.Monad.Trans.Class( lift )
+
+import Data.Bits( (.&.), (.|.)
+                , unsafeShiftR
+                , unsafeShiftL
+                , testBit, setBit )
+import Data.Word( Word8, Word16 )
+
+import qualified Data.ByteString as B
+import qualified Data.ByteString.Char8 as BC
+import qualified Data.ByteString.Lazy as L
+import qualified Data.Vector.Storable as V
+import qualified Data.Vector.Storable.Mutable as M
+
+import Data.Binary( Binary(..), encode )
+import Data.Binary.Get( Get
+                      , getWord8
+                      , getWord16le
+                      , getByteString
+                      , bytesRead
+                      , skip
+                      )
+
+import Data.Binary.Put( Put
+                      , putWord8
+                      , putWord16le
+                      , putByteString
+                      )
+
+import Codec.Picture.InternalHelper
+import Codec.Picture.Types
+import Codec.Picture.Metadata( Metadatas
+                             , SourceFormat( SourceGif )
+                             , basicMetadata )
+import Codec.Picture.Gif.Internal.LZW
+import Codec.Picture.Gif.Internal.LZWEncoding
+import Codec.Picture.BitWriter
+
+-- | Delay to wait before showing the next Gif image.
+-- The delay is expressed in 100th of seconds.
+type GifDelay = Int
+
+-- | Help to control the behaviour of GIF animation looping.
+data GifLooping =
+      -- | The animation will stop once the end is reached
+      LoopingNever
+      -- | The animation will restart once the end is reached
+    | LoopingForever
+      -- | The animation will repeat n times before stoping
+    | LoopingRepeat Word16
+
+
+-- | GIF image definition for encoding
+data GifEncode = GifEncode
+  { -- | Screen width
+    geWidth      :: Int
+  , -- | Screen height
+    geHeight     :: Int
+  , -- | Global palette, optional
+    gePalette    :: Maybe Palette
+  , -- | Background color index, optional. If given, a global palette is also required
+    geBackground :: Maybe Int
+  , -- | Looping behaviour
+    geLooping    :: GifLooping
+  , -- | Image frames
+    geFrames     :: [GifFrame]
+  }
+
+-- | An individual image frame in a GIF image
+data GifFrame = GifFrame
+  { -- | Image X offset in GIF canvas
+    gfXOffset     :: Int
+  , -- | Image Y offset in GIF canvas
+    gfYOffset     :: Int
+  , -- | Image local palette, optional if a global palette is given
+    gfPalette     :: Maybe Palette
+  , -- | Transparent color index, optional
+    gfTransparent :: Maybe Int
+  , -- | Frame transition delay, in 1/100ths of a second
+    gfDelay       :: GifDelay
+  , -- | Frame disposal method
+    gfDisposal    :: GifDisposalMethod
+  , -- | Image pixels
+    gfPixels      :: Image Pixel8
+  }
+
+
+{-
+   <GIF Data Stream> ::=     Header <Logical Screen> <Data>* Trailer
+
+   <Logical Screen> ::=      Logical Screen Descriptor [Global Color Table]
+
+   <Data> ::=                <Graphic Block>  |
+                             <Special-Purpose Block>
+
+   <Graphic Block> ::=       [Graphic Control Extension] <Graphic-Rendering Block>
+
+   <Graphic-Rendering Block> ::=  <Table-Based Image>  |
+                                  Plain Text Extension
+
+   <Table-Based Image> ::=   Image Descriptor [Local Color Table] Image Data
+
+   <Special-Purpose Block> ::=    Application Extension  |
+                                  Comment Extension
+ -}
+
+--------------------------------------------------
+----            GifVersion
+--------------------------------------------------
+data GifVersion = GIF87a | GIF89a
+
+gif87aSignature, gif89aSignature :: B.ByteString
+gif87aSignature = B.pack $ map (fromIntegral . fromEnum) "GIF87a"
+gif89aSignature = B.pack $ map (fromIntegral . fromEnum) "GIF89a"
+
+instance Binary GifVersion where
+    put GIF87a = putByteString gif87aSignature
+    put GIF89a = putByteString gif89aSignature
+
+    get = do
+        sig <- getByteString (B.length gif87aSignature)
+        case (sig == gif87aSignature, sig == gif89aSignature) of
+            (True, _)  -> pure GIF87a
+            (_ , True) -> pure GIF89a
+            _          -> fail $ "Invalid Gif signature : " ++ (toEnum . fromEnum <$> B.unpack sig)
+
+
+--------------------------------------------------
+----         LogicalScreenDescriptor
+--------------------------------------------------
+-- | Section 18 of spec-gif89a
+data LogicalScreenDescriptor = LogicalScreenDescriptor
+  { -- | Stored on 16 bits
+    screenWidth           :: !Word16
+    -- | Stored on 16 bits
+  , screenHeight          :: !Word16
+    -- | Stored on 8 bits
+  , backgroundIndex       :: !Word8
+
+  -- | Stored on 1 bit
+  , hasGlobalMap          :: !Bool
+  -- | Stored on 3 bits
+  , colorResolution       :: !Word8
+  -- | Stored on 1 bit
+  , isColorTableSorted    :: !Bool
+  -- | Stored on 3 bits
+  , colorTableSize        :: !Word8
+  }
+
+instance Binary LogicalScreenDescriptor where
+    put v = do
+      putWord16le $ screenWidth v
+      putWord16le $ screenHeight v
+      let globalMapField
+            | hasGlobalMap v = 0x80
+            | otherwise = 0
+
+          colorTableSortedField
+            | isColorTableSorted v = 0x08
+            | otherwise = 0
+
+          tableSizeField = (colorTableSize v - 1) .&. 7
+
+          colorResolutionField =
+            ((colorResolution v - 1) .&. 7) `unsafeShiftL` 4
+
+          packedField = globalMapField
+                     .|. colorTableSortedField
+                     .|. tableSizeField
+                     .|. colorResolutionField
+
+      putWord8 packedField
+      putWord8 0 -- aspect ratio
+      putWord8 $ backgroundIndex v
+
+    get = do
+        w <- getWord16le
+        h <- getWord16le
+        packedField  <- getWord8
+        backgroundColorIndex  <- getWord8
+        _aspectRatio  <- getWord8
+        return LogicalScreenDescriptor
+            { screenWidth           = w
+            , screenHeight          = h
+            , hasGlobalMap          = packedField `testBit` 7
+            , colorResolution       = (packedField `unsafeShiftR` 4) .&. 0x7 + 1
+            , isColorTableSorted    = packedField `testBit` 3
+            , colorTableSize        = (packedField .&. 0x7) + 1
+            , backgroundIndex       = backgroundColorIndex
+            }
+
+
+--------------------------------------------------
+----            ImageDescriptor
+--------------------------------------------------
+-- | Section 20 of spec-gif89a
+data ImageDescriptor = ImageDescriptor
+  { gDescPixelsFromLeft         :: !Word16
+  , gDescPixelsFromTop          :: !Word16
+  , gDescImageWidth             :: !Word16
+  , gDescImageHeight            :: !Word16
+  , gDescHasLocalMap            :: !Bool
+  , gDescIsInterlaced           :: !Bool
+  , gDescIsImgDescriptorSorted  :: !Bool
+  , gDescLocalColorTableSize    :: !Word8
+  }
+
+imageSeparator, extensionIntroducer, gifTrailer :: Word8
+imageSeparator      = 0x2C
+extensionIntroducer = 0x21
+gifTrailer          = 0x3B
+
+graphicControlLabel, commentLabel, plainTextLabel, applicationLabel :: Word8
+plainTextLabel = 0x01
+graphicControlLabel = 0xF9
+commentLabel = 0xFE
+applicationLabel    = 0xFF
+
+
+parseDataBlocks :: Get B.ByteString
+parseDataBlocks = B.concat <$> (getWord8 >>= aux)
+ where aux    0 = pure []
+       aux size = (:) <$> getByteString (fromIntegral size) <*> (getWord8 >>= aux)
+
+putDataBlocks :: B.ByteString -> Put
+putDataBlocks wholeString = putSlices wholeString >> putWord8 0
+  where putSlices str | B.length str == 0 = pure ()
+                      | B.length str > 0xFF =
+            let (before, after) = B.splitAt 0xFF str in
+            putWord8 0xFF >> putByteString before >> putSlices after
+        putSlices str =
+            putWord8 (fromIntegral $ B.length str) >> putByteString str
+
+data GifDisposalMethod
+    = DisposalAny
+    | DisposalDoNot
+    | DisposalRestoreBackground
+    | DisposalRestorePrevious
+    | DisposalUnknown Word8
+
+disposalMethodOfCode :: Word8 -> GifDisposalMethod
+disposalMethodOfCode v = case v of
+    0 -> DisposalAny
+    1 -> DisposalDoNot
+    2 -> DisposalRestoreBackground
+    3 -> DisposalRestorePrevious
+    n -> DisposalUnknown n
+
+codeOfDisposalMethod :: GifDisposalMethod -> Word8
+codeOfDisposalMethod v = case v of
+    DisposalAny -> 0
+    DisposalDoNot -> 1
+    DisposalRestoreBackground -> 2
+    DisposalRestorePrevious -> 3
+    DisposalUnknown n -> n
+
+data GraphicControlExtension = GraphicControlExtension
+    { gceDisposalMethod        :: !GifDisposalMethod -- ^ Stored on 3 bits
+    , gceUserInputFlag         :: !Bool
+    , gceTransparentFlag       :: !Bool
+    , gceDelay                 :: !Word16
+    , gceTransparentColorIndex :: !Word8
+    }
+
+instance Binary GraphicControlExtension where
+    put v = do
+        putWord8 extensionIntroducer
+        putWord8 graphicControlLabel
+        putWord8 0x4  -- size
+        let disposalCode = codeOfDisposalMethod $ gceDisposalMethod v
+            disposalField =
+                (disposalCode .&. 0x7) `unsafeShiftL` 2
+
+            userInputField
+                | gceUserInputFlag v = 0 `setBit` 1
+                | otherwise = 0
+
+            transparentField
+                | gceTransparentFlag v = 0 `setBit` 0
+                | otherwise = 0
+
+            packedFields =  disposalField
+                        .|. userInputField
+                        .|. transparentField
+
+        putWord8 packedFields
+        putWord16le $ gceDelay v
+        putWord8 $ gceTransparentColorIndex v
+        putWord8 0 -- blockTerminator
+
+    get = do
+        -- due to missing lookahead
+        {-_extensionLabel  <- getWord8-}
+        _size            <- getWord8
+        packedFields     <- getWord8
+        delay            <- getWord16le
+        idx              <- getWord8
+        _blockTerminator <- getWord8
+        return GraphicControlExtension
+            { gceDisposalMethod        = 
+                disposalMethodOfCode $
+                    (packedFields `unsafeShiftR` 2) .&. 0x07
+            , gceUserInputFlag         = packedFields `testBit` 1
+            , gceTransparentFlag       = packedFields `testBit` 0
+            , gceDelay                 = delay
+            , gceTransparentColorIndex = idx
+            }
+
+data GifImage = GifImage
+    { imgDescriptor   :: !ImageDescriptor
+    , imgLocalPalette :: !(Maybe Palette)
+    , imgLzwRootSize  :: !Word8
+    , imgData         :: B.ByteString
+    }
+
+instance Binary GifImage where
+    put img = do
+        let descriptor = imgDescriptor img
+        put descriptor
+        case ( imgLocalPalette img
+             , gDescHasLocalMap $ imgDescriptor img) of
+          (Nothing, _) -> return ()
+          (Just _, False) -> return ()
+          (Just p, True) ->
+              putPalette (fromIntegral $ gDescLocalColorTableSize descriptor) p
+        putWord8 $ imgLzwRootSize img
+        putDataBlocks $ imgData img
+
+    get = do
+        desc <- get
+        let hasLocalColorTable = gDescHasLocalMap desc
+        palette <- if hasLocalColorTable
+           then Just <$> getPalette (gDescLocalColorTableSize desc)
+           else pure Nothing
+
+        GifImage desc palette <$> getWord8 <*> parseDataBlocks
+
+data Block = BlockImage GifImage
+           | BlockGraphicControl GraphicControlExtension
+
+skipSubDataBlocks :: Get ()
+skipSubDataBlocks = do
+  s <- fromIntegral <$> getWord8
+  unless (s == 0) $
+    skip s >> skipSubDataBlocks
+
+parseGifBlocks :: Get [Block]
+parseGifBlocks = getWord8 >>= blockParse
+  where
+    blockParse v
+      | v == gifTrailer = pure []
+      | v == imageSeparator = (:) <$> (BlockImage <$> get) <*> parseGifBlocks
+      | v == extensionIntroducer = getWord8 >>= extensionParse
+
+    blockParse v = do
+      readPosition <- bytesRead
+      fail ("Unrecognized gif block " ++ show v ++ " @" ++ show readPosition)
+
+    extensionParse code
+     | code == graphicControlLabel =
+        (:) <$> (BlockGraphicControl <$> get) <*> parseGifBlocks
+     | code == commentLabel = skipSubDataBlocks >> parseGifBlocks
+     | code `elem` [plainTextLabel, applicationLabel] =
+        fromIntegral <$> getWord8 >>= skip >> skipSubDataBlocks >> parseGifBlocks
+     | otherwise = parseDataBlocks >> parseGifBlocks
+
+
+instance Binary ImageDescriptor where
+    put v = do
+        putWord8 imageSeparator
+        putWord16le $ gDescPixelsFromLeft v
+        putWord16le $ gDescPixelsFromTop v
+        putWord16le $ gDescImageWidth v
+        putWord16le $ gDescImageHeight v
+        let localMapField
+                | gDescHasLocalMap v = 0 `setBit` 7
+                | otherwise = 0
+
+            isInterlacedField
+                | gDescIsInterlaced v = 0 `setBit` 6
+                | otherwise = 0
+
+            isImageDescriptorSorted
+                | gDescIsImgDescriptorSorted v = 0 `setBit` 5
+                | otherwise = 0
+
+            localSize = gDescLocalColorTableSize v
+            tableSizeField
+                | localSize > 0 = (localSize - 1) .&. 0x7
+                | otherwise = 0
+
+            packedFields = localMapField
+                        .|. isInterlacedField
+                        .|. isImageDescriptorSorted
+                        .|. tableSizeField
+        putWord8 packedFields
+
+    get = do
+        -- due to missing lookahead
+        {-_imageSeparator <- getWord8-}
+        imgLeftPos <- getWord16le
+        imgTopPos  <- getWord16le
+        imgWidth   <- getWord16le
+        imgHeight  <- getWord16le
+        packedFields <- getWord8
+        return ImageDescriptor
+            { gDescPixelsFromLeft = imgLeftPos
+            , gDescPixelsFromTop  = imgTopPos
+            , gDescImageWidth     = imgWidth
+            , gDescImageHeight    = imgHeight
+            , gDescHasLocalMap    = packedFields `testBit` 7
+            , gDescIsInterlaced     = packedFields `testBit` 6
+            , gDescIsImgDescriptorSorted = packedFields `testBit` 5
+            , gDescLocalColorTableSize = (packedFields .&. 0x7) + 1
+            }
+
+
+--------------------------------------------------
+----            Palette
+--------------------------------------------------
+getPalette :: Word8 -> Get Palette
+getPalette bitDepth = 
+    Image size 1 . V.fromList <$> replicateM (size * 3) get
+  where size = 2 ^ (fromIntegral bitDepth :: Int)
+
+putPalette :: Int -> Palette -> Put
+putPalette size pal = do
+    V.mapM_ putWord8 (imageData pal)
+    replicateM_ missingColorComponent (putWord8 0)
+  where elemCount = 2 ^ size
+        missingColorComponent = (elemCount - imageWidth pal) * 3
+
+--------------------------------------------------
+----            GifImage
+--------------------------------------------------
+data GifHeader = GifHeader
+  { gifVersion          :: GifVersion
+  , gifScreenDescriptor :: LogicalScreenDescriptor
+  , gifGlobalMap        :: Maybe Palette
+  }
+
+instance Binary GifHeader where
+    put v = do
+      put $ gifVersion v
+      let descr = gifScreenDescriptor v
+      put descr
+      case gifGlobalMap v of
+        Just palette -> putPalette (fromIntegral $ colorTableSize descr) palette
+        Nothing      -> return ()
+
+    get = do
+        version    <- get
+        screenDesc <- get
+        
+        palette <- 
+          if hasGlobalMap screenDesc then
+            return <$> getPalette (colorTableSize screenDesc)
+          else
+            return Nothing
+
+        return GifHeader
+            { gifVersion = version
+            , gifScreenDescriptor = screenDesc
+            , gifGlobalMap = palette
+            }
+
+data GifFile = GifFile
+    { gifHeader      :: !GifHeader
+    , gifImages      :: [(Maybe GraphicControlExtension, GifImage)]
+    , gifLoopingBehaviour :: GifLooping
+    }
+
+putLooping :: GifLooping -> Put
+putLooping LoopingNever = return ()
+putLooping LoopingForever = putLooping $ LoopingRepeat 0
+putLooping (LoopingRepeat count) = do
+    putWord8 extensionIntroducer
+    putWord8 applicationLabel
+    putWord8 11 -- the size
+    putByteString $ BC.pack "NETSCAPE2.0"
+    putWord8 3 -- size of sub block
+    putWord8 1
+    putWord16le count
+    putWord8 0
+
+associateDescr :: [Block] -> [(Maybe GraphicControlExtension, GifImage)]
+associateDescr [] = []
+associateDescr [BlockGraphicControl _] = []
+associateDescr (BlockGraphicControl _ : rest@(BlockGraphicControl _ : _)) =
+    associateDescr rest
+associateDescr (BlockImage img:xs) = (Nothing, img) : associateDescr xs
+associateDescr (BlockGraphicControl ctrl : BlockImage img : xs) =
+    (Just ctrl, img) : associateDescr xs
+
+instance Binary GifFile where
+    put v = do
+        put $ gifHeader v
+        let putter (Nothing, i) = put i
+            putter (Just a, i) = put a >> put i
+        putLooping $ gifLoopingBehaviour v
+        mapM_ putter $ gifImages v
+        put gifTrailer
+
+    get = do
+        hdr <- get
+        blocks <- parseGifBlocks
+        return GifFile { gifHeader = hdr
+                       , gifImages = associateDescr blocks
+                       , gifLoopingBehaviour = LoopingNever
+                       }
+
+substituteColors :: Palette -> Image Pixel8 -> Image PixelRGB8
+substituteColors palette = pixelMap swaper
+  where swaper n = pixelAt palette (fromIntegral n) 0
+
+substituteColorsWithTransparency :: Int -> Image PixelRGBA8 -> Image Pixel8 -> Image PixelRGBA8
+substituteColorsWithTransparency transparent palette = pixelMap swaper where
+  swaper n | ix == transparent = PixelRGBA8 0 0 0 0
+           | otherwise = promotePixel $ pixelAt palette ix 0
+    where ix = fromIntegral n
+
+
+decodeImage :: GifImage -> Image Pixel8
+decodeImage img = runST $ runBoolReader $ do
+    outputVector <- lift . M.new $ width * height
+    decodeLzw (imgData img) 12 lzwRoot outputVector
+    frozenData <- lift $ V.unsafeFreeze outputVector
+    return . deinterlaceGif $ Image
+      { imageWidth = width
+      , imageHeight = height
+      , imageData = frozenData
+      }
+  where lzwRoot = fromIntegral $ imgLzwRootSize img
+        width = fromIntegral $ gDescImageWidth descriptor
+        height = fromIntegral $ gDescImageHeight descriptor
+        isInterlaced = gDescIsInterlaced descriptor
+        descriptor = imgDescriptor img
+
+        deinterlaceGif | not isInterlaced = id
+                       | otherwise = deinterlaceGifImage
+
+deinterlaceGifImage :: Image Pixel8 -> Image Pixel8
+deinterlaceGifImage img@(Image { imageWidth = w, imageHeight = h }) = generateImage generator w h
+   where lineIndices = gifInterlacingIndices h
+         generator x y = pixelAt img x y'
+            where y' = lineIndices V.! y
+
+gifInterlacingIndices :: Int -> V.Vector Int
+gifInterlacingIndices height = V.accum (\_ v -> v) (V.replicate height 0) indices
+    where indices = flip zip [0..] $
+                concat [ [0,     8 .. height - 1]
+                       , [4, 4 + 8 .. height - 1]
+                       , [2, 2 + 4 .. height - 1]
+                       , [1, 1 + 2 .. height - 1]
+                       ]
+
+paletteOf :: (ColorConvertible PixelRGB8 px)
+          => Image px -> GifImage -> Image px
+paletteOf global GifImage { imgLocalPalette = Nothing } = global
+paletteOf      _ GifImage { imgLocalPalette = Just p  } = promoteImage p
+
+getFrameDelays :: GifFile -> [GifDelay]
+getFrameDelays GifFile { gifImages = [] } = []
+getFrameDelays GifFile { gifImages = imgs } = map extractDelay imgs
+    where extractDelay (ext, _) =
+            case ext of
+                Nothing -> 0
+                Just e -> fromIntegral $ gceDelay e
+
+transparentColorOf :: Maybe GraphicControlExtension -> Int
+transparentColorOf Nothing = 300
+transparentColorOf (Just ext)
+  | gceTransparentFlag ext = fromIntegral $ gceTransparentColorIndex ext
+  | otherwise = 300
+
+hasTransparency :: Maybe GraphicControlExtension -> Bool
+hasTransparency Nothing = False
+hasTransparency (Just control) = gceTransparentFlag control
+
+decodeAllGifImages :: GifFile -> [PalettedImage]
+decodeAllGifImages GifFile { gifImages = [] } = []
+decodeAllGifImages GifFile { gifHeader = GifHeader { gifGlobalMap = palette
+                                                   , gifScreenDescriptor = wholeDescriptor }
+                           , gifImages = (firstControl, firstImage) : rest }
+  | not (hasTransparency firstControl) =
+      let backImage =
+              generateImage (\_ _ -> backgroundColor) globalWidth globalHeight
+          thisPalette = paletteOf globalPalette firstImage
+          baseImage = decodeImage firstImage
+          initState =
+            (thisPalette, firstControl, substituteColors thisPalette baseImage)
+          scanner = gifAnimationApplyer (globalWidth, globalHeight) thisPalette backImage
+          palette' = Palette'
+            { _paletteSize = imageWidth thisPalette
+            , _paletteData = imageData thisPalette
+            }
+      in
+      PalettedRGB8 baseImage palette' :
+        [TrueColorImage $ ImageRGB8 img | (_, _, img) <- tail $ scanl scanner initState rest]
+
+  | otherwise =
+      let backImage :: Image PixelRGBA8
+          backImage =
+            generateImage (\_ _ -> transparentBackground) globalWidth globalHeight
+
+          thisPalette :: Image PixelRGBA8
+          thisPalette = paletteOf (promoteImage globalPalette) firstImage
+
+          transparentCode = transparentColorOf firstControl
+          decoded = 
+            substituteColorsWithTransparency transparentCode thisPalette $
+                decodeImage firstImage
+
+          initState = (thisPalette, firstControl, decoded)
+          scanner =
+            gifAnimationApplyer (globalWidth, globalHeight) thisPalette backImage in
+      [TrueColorImage $ ImageRGBA8 img | (_, _, img) <- scanl scanner initState rest]
+
+    where
+      globalWidth = fromIntegral $ screenWidth wholeDescriptor
+      globalHeight = fromIntegral $ screenHeight wholeDescriptor
+      globalPalette = maybe greyPalette id palette
+
+      transparentBackground = PixelRGBA8 r g b 0
+          where PixelRGB8 r g b = backgroundColor
+
+      backgroundColor
+        | hasGlobalMap wholeDescriptor =
+            pixelAt globalPalette (fromIntegral $ backgroundIndex wholeDescriptor) 0
+        | otherwise = PixelRGB8 0 0 0
+
+gifAnimationApplyer :: forall px.  (ColorConvertible PixelRGB8 px)
+                    => (Int, Int) -> Image px -> Image px
+                    -> (Image px, Maybe GraphicControlExtension, Image px)
+                    -> (Maybe GraphicControlExtension, GifImage)
+                    -> (Image px, Maybe GraphicControlExtension, Image px)
+gifAnimationApplyer (globalWidth, globalHeight) globalPalette backgroundImage
+          (_, prevControl, img1)
+          (controlExt, img2@(GifImage { imgDescriptor = descriptor })) =
+            (thisPalette, controlExt, thisImage)
+  where
+    thisPalette :: Image px
+    thisPalette = paletteOf globalPalette img2
+
+    thisImage = generateImage pixeler globalWidth globalHeight
+    localWidth = fromIntegral $ gDescImageWidth descriptor
+    localHeight = fromIntegral $ gDescImageHeight descriptor
+
+    left = fromIntegral $ gDescPixelsFromLeft descriptor
+    top = fromIntegral $ gDescPixelsFromTop descriptor
+
+    isPixelInLocalImage x y =
+        x >= left && x < left + localWidth && y >= top && y < top + localHeight
+
+    decoded :: Image Pixel8
+    decoded = decodeImage img2
+
+    transparent :: Int
+    transparent = case controlExt of
+        Nothing  -> 300
+        Just ext -> if gceTransparentFlag ext
+            then fromIntegral $ gceTransparentColorIndex ext
+            else 300
+
+    oldImage = case gceDisposalMethod <$> prevControl of
+        Nothing -> img1
+        Just DisposalAny -> img1
+        Just DisposalDoNot -> img1
+        Just DisposalRestoreBackground -> backgroundImage
+        Just DisposalRestorePrevious -> img1
+        Just (DisposalUnknown _) -> img1
+
+    pixeler x y
+      | isPixelInLocalImage x y && code /= transparent = val where
+          code = fromIntegral $ pixelAt decoded (x - left) (y - top)
+          val = pixelAt thisPalette (fromIntegral code) 0
+    pixeler x y = pixelAt oldImage x y
+
+decodeFirstGifImage :: GifFile -> Either String (PalettedImage, Metadatas)
+decodeFirstGifImage img@GifFile { gifImages = (firstImage:_) } =
+    case decodeAllGifImages img { gifImages = [firstImage] } of
+      [] -> Left "No image after decoding"
+      (i:_) -> Right (i, basicMetadata SourceGif (screenWidth hdr) (screenHeight hdr))
+  where hdr = gifScreenDescriptor $ gifHeader img
+decodeFirstGifImage _ = Left "No image in gif file"
+
+-- | Transform a raw gif image to an image, without modifying the pixels. This
+-- function can output the following images:
+--
+--  * 'ImageRGB8'
+--
+--  * 'ImageRGBA8'
+--
+decodeGif :: B.ByteString -> Either String DynamicImage
+decodeGif img = decode img >>= (fmap (palettedToTrueColor . fst) . decodeFirstGifImage)
+
+-- | Transform a raw gif image to an image, without modifying the pixels.  This
+-- function can output the following images:
+--
+--  * 'ImageRGB8'
+--
+--  * 'ImageRGBA8'
+--
+-- Metadatas include Width & Height information.
+--
+decodeGifWithMetadata :: B.ByteString -> Either String (DynamicImage, Metadatas)
+decodeGifWithMetadata img = first palettedToTrueColor <$> decodeGifWithPaletteAndMetadata img
+
+-- | Return the gif image with metadata and palette.
+-- The palette is only returned for the first image of an
+-- animation and has no transparency.
+decodeGifWithPaletteAndMetadata :: B.ByteString -> Either String (PalettedImage, Metadatas)
+decodeGifWithPaletteAndMetadata img = decode img >>= decodeFirstGifImage
+
+-- | Transform a raw gif to a list of images, representing
+-- all the images of an animation.
+decodeGifImages :: B.ByteString -> Either String [DynamicImage]
+decodeGifImages img = fmap palettedToTrueColor . decodeAllGifImages <$> decode img
+
+-- | Extract a list of frame delays from a raw gif.
+getDelaysGifImages :: B.ByteString -> Either String [GifDelay]
+getDelaysGifImages img = getFrameDelays <$> decode img
+
+-- | Default palette to produce greyscale images.
+greyPalette :: Palette
+greyPalette = generateImage toGrey 256 1
+  where toGrey x _ = PixelRGB8 ix ix ix
+           where ix = fromIntegral x
+
+checkImageSizes :: GifEncode -> Either String ()
+checkImageSizes GifEncode { geWidth = width, geHeight = height, geFrames = frames }
+  | not $ isInBounds width && isInBounds height = Left "Invalid screen bounds"
+  | not $ null outOfBounds = Left $ "GIF frames with invalid bounds: " ++ show (map snd outOfBounds)
+  | otherwise = Right ()
+  where isInBounds dim = dim > 0 && dim <= 0xffff
+        outOfBounds = filter (not . isFrameInBounds . fst) $ zip frames [0 :: Int ..]
+        isFrameInBounds GifFrame { gfPixels = img } = isInBounds (imageWidth img) && isInBounds (imageHeight img)
+
+checkImagesInBounds :: GifEncode -> Either String ()
+checkImagesInBounds GifEncode { geWidth = width, geHeight = height, geFrames = frames } =
+  if null outOfBounds
+  then Right ()
+  else Left $ "GIF frames out of screen bounds: " ++ show (map snd outOfBounds)
+  where outOfBounds = filter (not . isInBounds . fst) $ zip frames [0 :: Int ..]
+        isInBounds GifFrame { gfXOffset = xOff, gfYOffset = yOff, gfPixels = img } =
+          xOff >= 0 && yOff >= 0 &&
+          xOff + imageWidth img <= width && yOff + imageHeight img <= height
+
+checkPaletteValidity :: GifEncode -> Either String ()
+checkPaletteValidity spec
+  | not $ isPaletteValid $ gePalette spec = Left "Invalid global palette size"
+  | not $ null invalidPalettes = Left $ "Invalid palette size in GIF frames: " ++ show (map snd invalidPalettes)
+  | otherwise = Right ()
+  where invalidPalettes = filter (not . isPaletteValid . gfPalette . fst) $ zip (geFrames spec) [0 :: Int ..]
+        isPaletteValid Nothing  = True
+        isPaletteValid (Just p) = let w = imageWidth p
+                                      h = imageHeight p
+                                  in h == 1 && w > 0 && w <= 256
+
+checkIndexAbsentFromPalette :: GifEncode -> Either String ()
+checkIndexAbsentFromPalette GifEncode { gePalette = global, geFrames = frames } =
+  if null missingPalette
+  then Right ()
+  else Left $ "GIF image frames with color indexes missing from palette: " ++ show (map snd missingPalette)
+  where missingPalette = filter (not . checkFrame . fst) $ zip frames [0 :: Int ..]
+        checkFrame frame = V.all (checkIndexInPalette global (gfPalette frame) . fromIntegral) $
+                           imageData $ gfPixels frame
+
+checkBackground :: GifEncode -> Either String ()
+checkBackground GifEncode { geBackground = Nothing } = Right ()
+checkBackground GifEncode { gePalette = global, geBackground = Just background } =
+  if checkIndexInPalette global Nothing background
+  then Right ()
+  else Left "GIF background index absent from global palette"
+
+checkTransparencies :: GifEncode -> Either String ()
+checkTransparencies GifEncode { gePalette = global, geFrames = frames } =
+  if null missingTransparency
+  then Right ()
+  else Left $ "GIF transparent index absent from palettes for frames: " ++ show (map snd missingTransparency)
+  where missingTransparency = filter (not . transparencyOK . fst) $ zip frames [0 :: Int ..]
+        transparencyOK GifFrame { gfTransparent = Nothing } = True
+        transparencyOK GifFrame { gfPalette = local, gfTransparent = Just transparent } =
+          checkIndexInPalette global local transparent
+
+checkIndexInPalette :: Maybe Palette -> Maybe Palette -> Int -> Bool
+checkIndexInPalette Nothing       Nothing      _  = False
+checkIndexInPalette _             (Just local) ix = ix < imageWidth local
+checkIndexInPalette (Just global) _            ix = ix < imageWidth global
+
+checkGifImageSizes :: [(a, b, Image px)] -> Bool
+checkGifImageSizes [] = False
+checkGifImageSizes ((_, _, img) : rest) = all checkDimension rest
+   where width = imageWidth img
+         height = imageHeight img
+
+         checkDimension (_,_,Image { imageWidth = w, imageHeight = h }) =
+             w == width && h == height
+
+computeColorTableSize :: Palette -> Int
+computeColorTableSize Image { imageWidth = itemCount } = go 1
+  where go k | 2 ^ k >= itemCount = k
+             | otherwise = go $ k + 1
+
+-- | Encode a complex gif to a bytestring.
+--
+-- * There must be at least one image.
+--
+-- * The screen and every frame dimensions must be between 1 and 65535.
+--
+-- * Every frame image must fit within the screen bounds.
+--
+-- * Every palette must have between one and 256 colors.
+--
+-- * There must be a global palette or every image must have a local palette.
+--
+-- * The background color index must be present in the global palette.
+--
+-- * Every frame's transparent color index, if set, must be present in the palette used by that frame.
+--
+-- * Every color index used in an image must be present in the palette used by that frame.
+--
+encodeComplexGifImage :: GifEncode -> Either String L.ByteString
+encodeComplexGifImage spec = do
+  when (null $ geFrames spec) $ Left "No GIF frames"
+  checkImageSizes spec
+  checkImagesInBounds spec
+  checkPaletteValidity spec
+  checkBackground spec
+  checkTransparencies spec
+  checkIndexAbsentFromPalette spec
+
+  Right $ encode allFile
+  where
+    GifEncode { geWidth      = width
+              , geHeight     = height
+              , gePalette    = globalPalette
+              , geBackground = background
+              , geLooping    = looping
+              , geFrames     = frames
+              } = spec
+    allFile = GifFile
+      { gifHeader = GifHeader
+        { gifVersion          = version
+        , gifScreenDescriptor = logicalScreen
+        , gifGlobalMap        = globalPalette
+        }
+      , gifImages           = toSerialize
+      , gifLoopingBehaviour = looping
+      }
+
+    version = case frames of
+      [] -> GIF87a
+      [_] -> GIF87a
+      _:_:_ -> GIF89a
+
+    logicalScreen = LogicalScreenDescriptor
+      { screenWidth        = fromIntegral width
+      , screenHeight       = fromIntegral height
+      , backgroundIndex    = maybe 0 fromIntegral background
+      , hasGlobalMap       = maybe False (const True) globalPalette
+      , colorResolution    = 8
+      , isColorTableSorted = False
+      -- Imply a 8 bit global palette size if there's no explicit global palette.
+      , colorTableSize     = maybe 8 (fromIntegral . computeColorTableSize) globalPalette
+      }
+
+    toSerialize = [(controlExtension delay transparent disposal, GifImage
+                     { imgDescriptor = imageDescriptor left top localPalette img
+                     , imgLocalPalette = localPalette
+                     , imgLzwRootSize = fromIntegral lzwKeySize
+                     , imgData = B.concat . L.toChunks . lzwEncode lzwKeySize $ imageData img
+                     })
+                  | GifFrame { gfXOffset     = left
+                             , gfYOffset     = top
+                             , gfPalette     = localPalette
+                             , gfTransparent = transparent
+                             , gfDelay       = delay
+                             , gfDisposal    = disposal
+                             , gfPixels      = img } <- frames
+                  , let palette = case (globalPalette, localPalette) of
+                          (_, Just local)        -> local
+                          (Just global, Nothing) -> global
+                          (Nothing, Nothing)     -> error "No palette for image" -- redundant, we guard for this
+                    -- Some decoders (looking at you, GIMP) don't handle initial LZW key size of 1 correctly.
+                    -- We'll waste some space for the sake of interoperability
+                  , let lzwKeySize = max 2 $ computeColorTableSize palette
+                  ]
+
+    controlExtension 0     Nothing     DisposalAny = Nothing
+    controlExtension delay transparent disposal    = Just GraphicControlExtension
+      { gceDisposalMethod        = disposal
+      , gceUserInputFlag         = False
+      , gceTransparentFlag       = maybe False (const True) transparent
+      , gceDelay                 = fromIntegral delay
+      , gceTransparentColorIndex = maybe 0 fromIntegral transparent
+      }
+
+    imageDescriptor left top localPalette img = ImageDescriptor
+      { gDescPixelsFromLeft         = fromIntegral left
+      , gDescPixelsFromTop          = fromIntegral top
+      , gDescImageWidth             = fromIntegral $ imageWidth img
+      , gDescImageHeight            = fromIntegral $ imageHeight img
+      , gDescHasLocalMap            = maybe False (const True) localPalette
+      , gDescIsInterlaced           = False
+      , gDescIsImgDescriptorSorted  = False
+      , gDescLocalColorTableSize    = maybe 0 (fromIntegral . computeColorTableSize) localPalette
+      }
+
+-- | Encode a gif animation to a bytestring.
+--
+-- * Every image must have the same size
+--
+-- * Every palette must have between one and 256 colors.
+--
+encodeGifImages :: GifLooping -> [(Palette, GifDelay, Image Pixel8)]
+                -> Either String L.ByteString
+encodeGifImages _ [] = Left "No image in list"
+encodeGifImages _ imageList
+    | not $ checkGifImageSizes imageList = Left "Gif images have different size"
+encodeGifImages looping imageList@((firstPalette, _,firstImage):_) =
+  encodeComplexGifImage $ GifEncode (imageWidth firstImage) (imageHeight firstImage) (Just firstPalette) Nothing looping frames
+  where
+    frames = [ GifFrame 0 0 localPalette Nothing delay DisposalAny image
+             | (palette, delay, image) <- imageList
+             , let localPalette = if paletteEqual palette then Nothing else Just palette ]
+
+    paletteEqual p = imageData firstPalette == imageData p
+
+-- | Encode a greyscale image to a bytestring.
+encodeGifImage :: Image Pixel8 -> L.ByteString
+encodeGifImage img = case encodeGifImages LoopingNever [(greyPalette, 0, img)] of
+    Left err -> error $ "Impossible:" ++ err
+    Right v -> v
+
+-- | Encode an image with a given palette.
+-- Can return errors if the palette is ill-formed.
+--
+-- * A palette must have between 1 and 256 colors
+--
+encodeGifImageWithPalette :: Image Pixel8 -> Palette -> Either String L.ByteString
+encodeGifImageWithPalette img palette =
+    encodeGifImages LoopingNever [(palette, 0, img)]
+
+-- | Write a greyscale in a gif file on the disk.
+writeGifImage :: FilePath -> Image Pixel8 -> IO ()
+writeGifImage file = L.writeFile file . encodeGifImage
+
+-- | Write a list of images as a gif animation in a file.
+--
+-- * Every image must have the same size
+--
+-- * Every palette must have between one and 256 colors.
+--
+writeGifImages :: FilePath -> GifLooping -> [(Palette, GifDelay, Image Pixel8)]
+               -> Either String (IO ())
+writeGifImages file looping lst = L.writeFile file <$> encodeGifImages looping lst
+
+-- | Write a gif image with a palette to a file.
+--
+-- * A palette must have between 1 and 256 colors
+--
+writeGifImageWithPalette :: FilePath -> Image Pixel8 -> Palette
+                         -> Either String (IO ())
+writeGifImageWithPalette file img palette =
+    L.writeFile file <$> encodeGifImageWithPalette img palette
+
+writeComplexGifImage :: FilePath -> GifEncode -> Either String (IO ())
+writeComplexGifImage file spec = L.writeFile file <$> encodeComplexGifImage spec
+ src/Codec/Picture/Gif/Internal/LZW.hs view
@@ -0,0 +1,194 @@+{-# LANGUAGE CPP #-}
+module Codec.Picture.Gif.Internal.LZW( decodeLzw, decodeLzwTiff ) where
+
+#if !MIN_VERSION_base(4,8,0)
+import Control.Applicative( (<$>) )
+#endif
+
+import Data.Word( Word8 )
+import Control.Monad( when, unless )
+
+import Data.Bits( (.&.) )
+
+import Control.Monad.ST( ST )
+import Control.Monad.Trans.Class( MonadTrans, lift )
+
+import Foreign.Storable ( Storable )
+
+import qualified Data.ByteString as B
+import qualified Data.Vector.Storable.Mutable as M
+
+import Codec.Picture.BitWriter
+
+{-# INLINE (.!!!.) #-}
+(.!!!.) :: (Storable a) => M.STVector s a -> Int -> ST s a
+(.!!!.) = M.unsafeRead 
+        {-M.read-}
+
+{-# INLINE (..!!!..) #-}
+(..!!!..) :: (MonadTrans t, Storable a)
+          => M.STVector s a -> Int -> t (ST s) a
+(..!!!..) v idx = lift $ v .!!!. idx
+
+{-# INLINE (.<-.) #-}
+(.<-.) :: (Storable a) => M.STVector s a -> Int -> a -> ST s ()
+(.<-.) = M.unsafeWrite 
+         {-M.write-}
+
+{-# INLINE (..<-..) #-}
+(..<-..) :: (MonadTrans t, Storable a)
+         => M.STVector s a -> Int -> a -> t (ST s) ()
+(..<-..) v idx = lift . (v .<-. idx)
+
+
+duplicateData :: (MonadTrans t, Storable a)
+              => M.STVector s a -> M.STVector s a
+              -> Int -> Int -> Int -> t (ST s) ()
+duplicateData src dest sourceIndex size destIndex = lift $ aux sourceIndex destIndex
+  where endIndex = sourceIndex + size
+        aux i _ | i == endIndex  = return ()
+        aux i j = do
+          src .!!!. i >>= (dest .<-. j)
+          aux (i + 1) (j + 1)
+
+rangeSetter :: (Storable a, Num a)
+            => Int -> M.STVector s a
+            -> ST s (M.STVector s a)
+rangeSetter count vec = aux 0
+  where aux n | n == count = return vec
+        aux n = (vec .<-. n) (fromIntegral n) >> aux (n + 1)
+
+decodeLzw :: B.ByteString -> Int -> Int -> M.STVector s Word8
+          -> BoolReader s ()
+decodeLzw str maxBitKey initialKey outVec = do
+    setDecodedString str
+    lzw GifVariant maxBitKey initialKey 0 outVec
+
+isOldTiffLZW :: B.ByteString -> Bool
+isOldTiffLZW str = firstByte == 0 && secondByte == 1
+    where firstByte = str `B.index` 0
+          secondByte = (str `B.index` 1) .&. 1
+
+decodeLzwTiff :: B.ByteString -> M.STVector s Word8 -> Int
+              -> BoolReader s()
+decodeLzwTiff str outVec initialWriteIdx = do
+    if isOldTiffLZW str then
+      setDecodedString str
+    else
+      setDecodedStringMSB str
+    let variant | isOldTiffLZW str = OldTiffVariant
+                | otherwise = TiffVariant
+    lzw variant 12 9 initialWriteIdx outVec
+
+data TiffVariant =
+      GifVariant
+    | TiffVariant
+    | OldTiffVariant
+    deriving Eq
+
+-- | Gif image constraint from spec-gif89a, code size max : 12 bits.
+lzw :: TiffVariant -> Int -> Int -> Int -> M.STVector s Word8
+    -> BoolReader s ()
+lzw variant nMaxBitKeySize initialKeySize initialWriteIdx outVec = do
+    -- Allocate buffer of maximum size.
+    lzwData <- lift (M.replicate maxDataSize 0) >>= resetArray
+    lzwOffsetTable <- lift (M.replicate tableEntryCount 0) >>= resetArray
+    lzwSizeTable <- lift $ M.replicate tableEntryCount 0
+    lift $ lzwSizeTable `M.set` 1
+
+    let firstVal code = do
+            dataOffset <- lzwOffsetTable ..!!!.. code
+            lzwData ..!!!.. dataOffset
+
+        writeString at code = do
+            dataOffset <- lzwOffsetTable ..!!!.. code
+            dataSize   <- lzwSizeTable   ..!!!.. code
+
+            when (at + dataSize <= maxWrite) $
+                 duplicateData lzwData outVec dataOffset dataSize at
+
+            return dataSize
+
+        addString pos at code val = do
+            dataOffset <- lzwOffsetTable ..!!!.. code
+            dataSize   <- lzwSizeTable   ..!!!.. code
+
+            when (pos < tableEntryCount) $ do
+              (lzwOffsetTable ..<-.. pos) at
+              (lzwSizeTable ..<-.. pos) $ dataSize + 1
+
+            when (at + dataSize + 1 <= maxDataSize) $ do
+              duplicateData lzwData lzwData dataOffset dataSize at
+              (lzwData ..<-.. (at + dataSize)) val
+
+            return $ dataSize + 1
+
+        maxWrite = M.length outVec
+        loop outWriteIdx writeIdx dicWriteIdx codeSize oldCode code
+          | outWriteIdx >= maxWrite = return ()
+          | code == endOfInfo = return ()
+          | code == clearCode = do
+              toOutput <- getNextCode startCodeSize
+              unless (toOutput == endOfInfo) $ do
+                dataSize <- writeString outWriteIdx toOutput
+                getNextCode startCodeSize >>=
+                  loop (outWriteIdx + dataSize)
+                       firstFreeIndex firstFreeIndex startCodeSize toOutput
+
+          | otherwise =  do
+              (written, dicAdd) <-
+                   if code >= writeIdx then do
+                     c <- firstVal oldCode
+                     wroteSize <- writeString outWriteIdx oldCode
+                     (outVec ..<-.. (outWriteIdx + wroteSize)) c
+                     addedSize <- addString writeIdx dicWriteIdx oldCode c
+                     return (wroteSize + 1, addedSize)
+                   else do
+                     wroteSize <- writeString outWriteIdx code
+                     c <- firstVal code
+                     addedSize <- addString writeIdx dicWriteIdx oldCode c
+                     return (wroteSize, addedSize)
+
+              let new_code_size = updateCodeSize codeSize $ writeIdx + 1
+              getNextCode new_code_size >>=
+                loop (outWriteIdx + written)
+                     (writeIdx + 1)
+                     (dicWriteIdx + dicAdd)
+                     new_code_size
+                     code
+
+    getNextCode startCodeSize >>=
+        loop initialWriteIdx firstFreeIndex firstFreeIndex startCodeSize 0
+
+  where tableEntryCount =  2 ^ min 12 nMaxBitKeySize
+        maxDataSize = tableEntryCount `div` 2 * (1 + tableEntryCount) + 1
+
+        isNewTiff = variant == TiffVariant
+        (switchOffset,  isTiffVariant) = case variant of
+            GifVariant -> (0, False)
+            TiffVariant -> (1, True)
+            OldTiffVariant -> (0, True)
+
+        initialElementCount = 2 ^ initialKeySize :: Int
+        clearCode | isTiffVariant = 256
+                  | otherwise = initialElementCount
+
+        endOfInfo | isTiffVariant = 257
+                  | otherwise = clearCode + 1
+
+        startCodeSize 
+                  | isTiffVariant = initialKeySize
+                  | otherwise = initialKeySize + 1
+
+        firstFreeIndex = endOfInfo + 1
+
+        resetArray a = lift $ rangeSetter initialElementCount a
+
+        updateCodeSize codeSize writeIdx
+            | writeIdx == 2 ^ codeSize - switchOffset = min 12 $ codeSize + 1
+            | otherwise = codeSize
+
+        getNextCode s 
+            | isNewTiff = fromIntegral <$> getNextBitsMSBFirst s
+            | otherwise = fromIntegral <$> getNextBitsLSBFirst s
+
+ src/Codec/Picture/Gif/Internal/LZWEncoding.hs view
@@ -0,0 +1,101 @@+{-# LANGUAGE BangPatterns, CPP #-}
+module Codec.Picture.Gif.Internal.LZWEncoding( lzwEncode ) where
+
+#if !MIN_VERSION_base(4,8,0)
+import Control.Applicative( (<$>) )
+import Data.Monoid( mempty )
+#endif
+
+import Control.Monad.ST( runST )
+import qualified Data.ByteString.Lazy as L
+import Data.Maybe( fromMaybe )
+import Data.Word( Word8 )
+
+#if MIN_VERSION_containers(0,5,0)
+import qualified Data.IntMap.Strict as I
+#else
+import qualified Data.IntMap as I
+#endif
+import qualified Data.Vector.Storable as V
+
+import Codec.Picture.BitWriter
+
+type Trie = I.IntMap TrieNode
+
+data TrieNode = TrieNode
+    { trieIndex :: {-# UNPACK #-} !Int
+    , trieSub   :: !Trie
+    }
+
+emptyNode :: TrieNode
+emptyNode = TrieNode
+    { trieIndex = -1
+    , trieSub = mempty
+    }
+
+initialTrie :: Trie
+initialTrie = I.fromList
+    [(i, emptyNode { trieIndex = i }) | i <- [0 .. 255]]
+
+lookupUpdate :: V.Vector Word8 -> Int -> Int -> Trie -> (Int, Int, Trie)
+lookupUpdate vector freeIndex firstIndex trie =
+    matchUpdate $ go trie 0 firstIndex 
+  where
+    matchUpdate (lzwOutputIndex, nextReadIndex, sub) =
+        (lzwOutputIndex, nextReadIndex, fromMaybe trie sub)
+
+    maxi = V.length vector
+    go !currentTrie !prevIndex !index
+      | index >= maxi = (prevIndex, index, Nothing)
+      | otherwise = case I.lookup val currentTrie of
+          Just (TrieNode ix subTable) ->
+              let (lzwOutputIndex, nextReadIndex, newTable) =
+                        go subTable ix $ index + 1
+                  tableUpdater t =
+                      I.insert val (TrieNode ix t) currentTrie
+              in
+              (lzwOutputIndex, nextReadIndex, tableUpdater <$> newTable)
+
+          Nothing | index == maxi -> (prevIndex, index, Nothing)
+                  | otherwise -> (prevIndex, index, Just $ I.insert val newNode currentTrie)
+
+      where val = fromIntegral $ vector `V.unsafeIndex` index
+            newNode = emptyNode { trieIndex = freeIndex }
+
+lzwEncode :: Int -> V.Vector Word8 -> L.ByteString
+lzwEncode initialKeySize vec = runST $ do
+    bitWriter <- newWriteStateRef 
+
+    let updateCodeSize 12 writeIdx _
+            | writeIdx == 2 ^ (12 :: Int) - 1 = do
+               writeBitsGif bitWriter (fromIntegral clearCode) 12
+               return (startCodeSize, firstFreeIndex, initialTrie)
+
+        updateCodeSize codeSize writeIdx trie
+            | writeIdx == 2 ^ codeSize =
+                return (codeSize + 1, writeIdx + 1, trie)
+            | otherwise = return (codeSize, writeIdx + 1, trie)
+
+        go readIndex (codeSize, _, _) | readIndex >= maxi =
+            writeBitsGif bitWriter (fromIntegral endOfInfo) codeSize
+        go !readIndex (!codeSize, !writeIndex, !trie) = do
+            let (indexToWrite, endIndex, trie') =
+                    lookuper writeIndex readIndex trie
+            writeBitsGif bitWriter (fromIntegral indexToWrite) codeSize
+            updateCodeSize codeSize writeIndex trie'
+                >>= go endIndex 
+
+    writeBitsGif bitWriter (fromIntegral clearCode) startCodeSize
+    go 0 (startCodeSize, firstFreeIndex, initialTrie)
+
+    finalizeBoolWriterGif bitWriter
+  where
+    maxi = V.length vec
+
+    startCodeSize = initialKeySize + 1
+
+    clearCode = 2 ^ initialKeySize :: Int
+    endOfInfo = clearCode + 1
+    firstFreeIndex = endOfInfo + 1
+    
+    lookuper = lookupUpdate vec
− src/Codec/Picture/Gif/LZW.hs
@@ -1,194 +0,0 @@-{-# LANGUAGE CPP #-}-module Codec.Picture.Gif.LZW( decodeLzw, decodeLzwTiff ) where--#if !MIN_VERSION_base(4,8,0)-import Control.Applicative( (<$>) )-#endif--import Data.Word( Word8 )-import Control.Monad( when, unless )--import Data.Bits( (.&.) )--import Control.Monad.ST( ST )-import Control.Monad.Trans.Class( MonadTrans, lift )--import Foreign.Storable ( Storable )--import qualified Data.ByteString as B-import qualified Data.Vector.Storable.Mutable as M--import Codec.Picture.BitWriter--{-# INLINE (.!!!.) #-}-(.!!!.) :: (Storable a) => M.STVector s a -> Int -> ST s a-(.!!!.) = M.unsafeRead -        {-M.read-}--{-# INLINE (..!!!..) #-}-(..!!!..) :: (MonadTrans t, Storable a)-          => M.STVector s a -> Int -> t (ST s) a-(..!!!..) v idx = lift $ v .!!!. idx--{-# INLINE (.<-.) #-}-(.<-.) :: (Storable a) => M.STVector s a -> Int -> a -> ST s ()-(.<-.) = M.unsafeWrite -         {-M.write-}--{-# INLINE (..<-..) #-}-(..<-..) :: (MonadTrans t, Storable a)-         => M.STVector s a -> Int -> a -> t (ST s) ()-(..<-..) v idx = lift . (v .<-. idx)---duplicateData :: (MonadTrans t, Storable a)-              => M.STVector s a -> M.STVector s a-              -> Int -> Int -> Int -> t (ST s) ()-duplicateData src dest sourceIndex size destIndex = lift $ aux sourceIndex destIndex-  where endIndex = sourceIndex + size-        aux i _ | i == endIndex  = return ()-        aux i j = do-          src .!!!. i >>= (dest .<-. j)-          aux (i + 1) (j + 1)--rangeSetter :: (Storable a, Num a)-            => Int -> M.STVector s a-            -> ST s (M.STVector s a)-rangeSetter count vec = aux 0-  where aux n | n == count = return vec-        aux n = (vec .<-. n) (fromIntegral n) >> aux (n + 1)--decodeLzw :: B.ByteString -> Int -> Int -> M.STVector s Word8-          -> BoolReader s ()-decodeLzw str maxBitKey initialKey outVec = do-    setDecodedString str-    lzw GifVariant maxBitKey initialKey 0 outVec--isOldTiffLZW :: B.ByteString -> Bool-isOldTiffLZW str = firstByte == 0 && secondByte == 1-    where firstByte = str `B.index` 0-          secondByte = (str `B.index` 1) .&. 1--decodeLzwTiff :: B.ByteString -> M.STVector s Word8 -> Int-              -> BoolReader s()-decodeLzwTiff str outVec initialWriteIdx = do-    if isOldTiffLZW str then-      setDecodedString str-    else-      setDecodedStringMSB str-    let variant | isOldTiffLZW str = OldTiffVariant-                | otherwise = TiffVariant-    lzw variant 12 9 initialWriteIdx outVec--data TiffVariant =-      GifVariant-    | TiffVariant-    | OldTiffVariant-    deriving Eq---- | Gif image constraint from spec-gif89a, code size max : 12 bits.-lzw :: TiffVariant -> Int -> Int -> Int -> M.STVector s Word8-    -> BoolReader s ()-lzw variant nMaxBitKeySize initialKeySize initialWriteIdx outVec = do-    -- Allocate buffer of maximum size.-    lzwData <- lift (M.replicate maxDataSize 0) >>= resetArray-    lzwOffsetTable <- lift (M.replicate tableEntryCount 0) >>= resetArray-    lzwSizeTable <- lift $ M.replicate tableEntryCount 0-    lift $ lzwSizeTable `M.set` 1--    let firstVal code = do-            dataOffset <- lzwOffsetTable ..!!!.. code-            lzwData ..!!!.. dataOffset--        writeString at code = do-            dataOffset <- lzwOffsetTable ..!!!.. code-            dataSize   <- lzwSizeTable   ..!!!.. code--            when (at + dataSize <= maxWrite) $-                 duplicateData lzwData outVec dataOffset dataSize at--            return dataSize--        addString pos at code val = do-            dataOffset <- lzwOffsetTable ..!!!.. code-            dataSize   <- lzwSizeTable   ..!!!.. code--            when (pos < tableEntryCount) $ do-              (lzwOffsetTable ..<-.. pos) at-              (lzwSizeTable ..<-.. pos) $ dataSize + 1--            when (at + dataSize + 1 <= maxDataSize) $ do-              duplicateData lzwData lzwData dataOffset dataSize at-              (lzwData ..<-.. (at + dataSize)) val--            return $ dataSize + 1--        maxWrite = M.length outVec-        loop outWriteIdx writeIdx dicWriteIdx codeSize oldCode code-          | outWriteIdx >= maxWrite = return ()-          | code == endOfInfo = return ()-          | code == clearCode = do-              toOutput <- getNextCode startCodeSize-              unless (toOutput == endOfInfo) $ do-                dataSize <- writeString outWriteIdx toOutput-                getNextCode startCodeSize >>=-                  loop (outWriteIdx + dataSize)-                       firstFreeIndex firstFreeIndex startCodeSize toOutput--          | otherwise =  do-              (written, dicAdd) <--                   if code >= writeIdx then do-                     c <- firstVal oldCode-                     wroteSize <- writeString outWriteIdx oldCode-                     (outVec ..<-.. (outWriteIdx + wroteSize)) c-                     addedSize <- addString writeIdx dicWriteIdx oldCode c-                     return (wroteSize + 1, addedSize)-                   else do-                     wroteSize <- writeString outWriteIdx code-                     c <- firstVal code-                     addedSize <- addString writeIdx dicWriteIdx oldCode c-                     return (wroteSize, addedSize)--              let new_code_size = updateCodeSize codeSize $ writeIdx + 1-              getNextCode new_code_size >>=-                loop (outWriteIdx + written)-                     (writeIdx + 1)-                     (dicWriteIdx + dicAdd)-                     new_code_size-                     code--    getNextCode startCodeSize >>=-        loop initialWriteIdx firstFreeIndex firstFreeIndex startCodeSize 0--  where tableEntryCount =  2 ^ min 12 nMaxBitKeySize-        maxDataSize = tableEntryCount `div` 2 * (1 + tableEntryCount) + 1--        isNewTiff = variant == TiffVariant-        (switchOffset,  isTiffVariant) = case variant of-            GifVariant -> (0, False)-            TiffVariant -> (1, True)-            OldTiffVariant -> (0, True)--        initialElementCount = 2 ^ initialKeySize :: Int-        clearCode | isTiffVariant = 256-                  | otherwise = initialElementCount--        endOfInfo | isTiffVariant = 257-                  | otherwise = clearCode + 1--        startCodeSize -                  | isTiffVariant = initialKeySize-                  | otherwise = initialKeySize + 1--        firstFreeIndex = endOfInfo + 1--        resetArray a = lift $ rangeSetter initialElementCount a--        updateCodeSize codeSize writeIdx-            | writeIdx == 2 ^ codeSize - switchOffset = min 12 $ codeSize + 1-            | otherwise = codeSize--        getNextCode s -            | isNewTiff = fromIntegral <$> getNextBitsMSBFirst s-            | otherwise = fromIntegral <$> getNextBitsLSBFirst s-
− src/Codec/Picture/Gif/LZWEncoding.hs
@@ -1,101 +0,0 @@-{-# LANGUAGE BangPatterns, CPP #-}-module Codec.Picture.Gif.LZWEncoding( lzwEncode ) where--#if !MIN_VERSION_base(4,8,0)-import Control.Applicative( (<$>) )-import Data.Monoid( mempty )-#endif--import Control.Monad.ST( runST )-import qualified Data.ByteString.Lazy as L-import Data.Maybe( fromMaybe )-import Data.Word( Word8 )--#if MIN_VERSION_containers(0,5,0)-import qualified Data.IntMap.Strict as I-#else-import qualified Data.IntMap as I-#endif-import qualified Data.Vector.Storable as V--import Codec.Picture.BitWriter--type Trie = I.IntMap TrieNode--data TrieNode = TrieNode-    { trieIndex :: {-# UNPACK #-} !Int-    , trieSub   :: !Trie-    }--emptyNode :: TrieNode-emptyNode = TrieNode-    { trieIndex = -1-    , trieSub = mempty-    }--initialTrie :: Trie-initialTrie = I.fromList-    [(i, emptyNode { trieIndex = i }) | i <- [0 .. 255]]--lookupUpdate :: V.Vector Word8 -> Int -> Int -> Trie -> (Int, Int, Trie)-lookupUpdate vector freeIndex firstIndex trie =-    matchUpdate $ go trie 0 firstIndex -  where-    matchUpdate (lzwOutputIndex, nextReadIndex, sub) =-        (lzwOutputIndex, nextReadIndex, fromMaybe trie sub)--    maxi = V.length vector-    go !currentTrie !prevIndex !index-      | index >= maxi = (prevIndex, index, Nothing)-      | otherwise = case I.lookup val currentTrie of-          Just (TrieNode ix subTable) ->-              let (lzwOutputIndex, nextReadIndex, newTable) =-                        go subTable ix $ index + 1-                  tableUpdater t =-                      I.insert val (TrieNode ix t) currentTrie-              in-              (lzwOutputIndex, nextReadIndex, tableUpdater <$> newTable)--          Nothing | index == maxi -> (prevIndex, index, Nothing)-                  | otherwise -> (prevIndex, index, Just $ I.insert val newNode currentTrie)--      where val = fromIntegral $ vector `V.unsafeIndex` index-            newNode = emptyNode { trieIndex = freeIndex }--lzwEncode :: Int -> V.Vector Word8 -> L.ByteString-lzwEncode initialKeySize vec = runST $ do-    bitWriter <- newWriteStateRef --    let updateCodeSize 12 writeIdx _-            | writeIdx == 2 ^ (12 :: Int) - 1 = do-               writeBitsGif bitWriter (fromIntegral clearCode) 12-               return (startCodeSize, firstFreeIndex, initialTrie)--        updateCodeSize codeSize writeIdx trie-            | writeIdx == 2 ^ codeSize =-                return (codeSize + 1, writeIdx + 1, trie)-            | otherwise = return (codeSize, writeIdx + 1, trie)--        go readIndex (codeSize, _, _) | readIndex >= maxi =-            writeBitsGif bitWriter (fromIntegral endOfInfo) codeSize-        go !readIndex (!codeSize, !writeIndex, !trie) = do-            let (indexToWrite, endIndex, trie') =-                    lookuper writeIndex readIndex trie-            writeBitsGif bitWriter (fromIntegral indexToWrite) codeSize-            updateCodeSize codeSize writeIndex trie'-                >>= go endIndex --    writeBitsGif bitWriter (fromIntegral clearCode) startCodeSize-    go 0 (startCodeSize, firstFreeIndex, initialTrie)--    finalizeBoolWriter bitWriter-  where-    maxi = V.length vec--    startCodeSize = initialKeySize + 1--    clearCode = 2 ^ initialKeySize :: Int-    endOfInfo = clearCode + 1-    firstFreeIndex = endOfInfo + 1-    -    lookuper = lookupUpdate vec
src/Codec/Picture/HDR.hs view
@@ -1,530 +1,534 @@-{-# LANGUAGE CPP #-}-{-# LANGUAGE TypeFamilies #-}-{-# LANGUAGE TupleSections   #-}--- | Module dedicated of Radiance file decompression (.hdr or .pic) file.--- Radiance file format is used for High dynamic range imaging.-module Codec.Picture.HDR( decodeHDR-                        , decodeHDRWithMetadata-                        , encodeHDR-                        , encodeRawHDR-                        , encodeRLENewStyleHDR-                        , writeHDR-                        , writeRLENewStyleHDR-                        ) where--#if !MIN_VERSION_base(4,8,0)-import Control.Applicative( pure, (<*>), (<$>) )-#endif--import Data.Bits( Bits, (.&.), (.|.), unsafeShiftL, unsafeShiftR )-import Data.Char( ord, chr, isDigit )-import Data.Word( Word8 )-import Data.Monoid( (<>) )-import Control.Monad( when, foldM, foldM_, forM, forM_, unless )-import Control.Monad.Trans.Class( lift )-import qualified Data.ByteString as B-import qualified Data.ByteString.Lazy as L-import qualified Data.ByteString.Char8 as BC--import Data.List( partition )-import Data.Binary( Binary( .. ), encode )-import Data.Binary.Get( Get, getByteString, getWord8 )-import Data.Binary.Put( putByteString, putLazyByteString )--import Control.Monad.ST( ST, runST )-import Foreign.Storable ( Storable )-import Control.Monad.Primitive ( PrimState, PrimMonad )-import qualified Data.Vector.Storable as V-import qualified Data.Vector.Storable.Mutable as M--import Codec.Picture.Metadata( Metadatas-                             , SourceFormat( SourceHDR )-                             , basicMetadata )-import Codec.Picture.InternalHelper-import Codec.Picture.Types-import Codec.Picture.VectorByteConversion--#if MIN_VERSION_transformers(0, 4, 0)-import Control.Monad.Trans.Except( ExceptT, throwE, runExceptT )-#else--- Transfomers 0.3 compat-import Control.Monad.Trans.Error( Error, ErrorT, throwError, runErrorT )--type ExceptT = ErrorT--throwE :: (Monad m, Error e) => e -> ErrorT e m a-throwE = throwError--runExceptT :: ErrorT e m a -> m (Either e a)-runExceptT = runErrorT-#endif--{-# INLINE (.<<.) #-}-(.<<.), (.>>.) :: (Bits a) => a -> Int -> a-(.<<.) = unsafeShiftL-(.>>.) = unsafeShiftR--{-# INLINE (.<-.) #-}-(.<-.) :: (PrimMonad m, Storable a)-       => M.STVector (PrimState m) a -> Int -> a -> m ()-(.<-.) = M.write -         {-M.unsafeWrite-}--type HDRReader s a = ExceptT String (ST s) a--data RGBE = RGBE !Word8 !Word8 !Word8 !Word8--instance Binary RGBE where-    put (RGBE r g b e) = put r >> put g >> put b >> put e-    get = RGBE <$> get <*> get <*> get <*> get--checkLineLength :: RGBE -> Int-checkLineLength (RGBE _ _ a b) =-    (fromIntegral a .<<. 8) .|. fromIntegral b--isNewRunLengthMarker :: RGBE -> Bool-isNewRunLengthMarker (RGBE 2 2 _ _) = True-isNewRunLengthMarker _ = False--data RadianceFormat =-      FormatRGBE-    | FormatXYZE--radiance32bitRleRGBEFormat, radiance32bitRleXYZEFromat :: B.ByteString-radiance32bitRleRGBEFormat = BC.pack "32-bit_rle_rgbe"-radiance32bitRleXYZEFromat = BC.pack "32-bit_rle_xyze"--instance Binary RadianceFormat where-  put FormatRGBE = putByteString radiance32bitRleRGBEFormat-  put FormatXYZE = putByteString radiance32bitRleXYZEFromat--  get = getByteString (B.length radiance32bitRleRGBEFormat) >>= format-    where format sig-            | sig == radiance32bitRleRGBEFormat = pure FormatRGBE-            | sig == radiance32bitRleXYZEFromat = pure FormatXYZE-            | otherwise = fail "Unrecognized Radiance format"--toRGBE :: PixelRGBF -> RGBE-toRGBE (PixelRGBF r g b)-    | d <= 1e-32 = RGBE 0 0 0 0-    | otherwise = RGBE (fix r) (fix g) (fix b) (fromIntegral $ e + 128)-  where d = maximum [r, g, b]-        e = exponent d-        coeff = significand d *  255.9999 / d-        fix v = truncate $ v * coeff---dropUntil :: Word8 -> Get ()-dropUntil c = getWord8 >>= inner-  where inner val | val == c = pure ()-        inner _ = getWord8 >>= inner--getUntil :: (Word8 -> Bool) -> B.ByteString -> Get B.ByteString-getUntil f initialAcc = getWord8 >>= inner initialAcc-  where inner acc c | f c = pure acc-        inner acc c = getWord8 >>= inner (B.snoc acc c)--data RadianceHeader = RadianceHeader-  { radianceInfos :: [(B.ByteString, B.ByteString)]-  , radianceFormat :: RadianceFormat-  , radianceHeight :: !Int-  , radianceWidth  :: !Int-  , radianceData   :: L.ByteString-  }--radianceFileSignature :: B.ByteString-radianceFileSignature = BC.pack "#?RADIANCE\n"--unpackColor :: L.ByteString -> Int -> RGBE-unpackColor str idx = RGBE (at 0) (at 1) (at 2) (at 3)-  where at n = L.index str . fromIntegral $ idx + n--storeColor :: M.STVector s Word8 -> Int -> RGBE -> ST s ()-storeColor vec idx (RGBE r g b e) = do-    (vec .<-. (idx + 0)) r-    (vec .<-. (idx + 1)) g-    (vec .<-. (idx + 2)) b-    (vec .<-. (idx + 3)) e--parsePair :: Char -> Get (B.ByteString, B.ByteString)-parsePair firstChar = do-    let eol c = c == fromIntegral (ord '\n')-    line <- getUntil eol B.empty-    case BC.split '=' line of-      [] -> pure (BC.singleton firstChar, B.empty)-      [val] -> pure (BC.singleton firstChar, val)-      [key, val] -> pure (BC.singleton firstChar <> key, val)-      (key : vals) -> pure (BC.singleton firstChar <> key, B.concat vals)--decodeInfos :: Get [(B.ByteString, B.ByteString)]-decodeInfos = do-    char <- getChar8-    case char of-      -- comment-      '#' -> dropUntil (fromIntegral $ ord '\n') >> decodeInfos-      -- end of header, no more information-      '\n' -> pure []-      -- Classical parsing-      c -> (:) <$> parsePair c <*> decodeInfos----- | Decode an HDR (radiance) image, the resulting image can be:------  * 'ImageRGBF'----decodeHDR :: B.ByteString -> Either String DynamicImage-decodeHDR = fmap fst . decodeHDRWithMetadata---- | Equivalent to decodeHDR but with aditional metadatas.-decodeHDRWithMetadata :: B.ByteString -> Either String (DynamicImage, Metadatas)-decodeHDRWithMetadata str = runST $ runExceptT $-  case runGet decodeHeader $ L.fromChunks [str] of-    Left err -> throwE err-    Right rez ->-      let meta = basicMetadata SourceHDR (abs $ radianceWidth rez) (abs $ radianceHeight rez) in-      (, meta) . ImageRGBF <$> (decodeRadiancePicture rez >>= lift . unsafeFreezeImage)--getChar8 :: Get Char-getChar8 = chr . fromIntegral <$> getWord8--isSign :: Char -> Bool-isSign c = c == '+' || c == '-'--isAxisLetter :: Char -> Bool-isAxisLetter c = c == 'X' || c == 'Y'--decodeNum :: Get Int-decodeNum = do-    sign <- getChar8-    letter <- getChar8-    space <- getChar8--    unless (isSign sign && isAxisLetter letter && space == ' ')-           (fail "Invalid radiance size declaration")--    let numDec acc c | isDigit c =-            getChar8 >>= numDec (acc * 10 + ord c - ord '0')-        numDec acc _-            | sign == '-' = pure $ negate acc-            | otherwise = pure acc--    getChar8 >>= numDec 0--copyPrevColor :: M.STVector s Word8 -> Int -> ST s ()-copyPrevColor scanLine idx = do-    r <- scanLine `M.unsafeRead` (idx - 4)-    g <- scanLine `M.unsafeRead` (idx - 3)-    b <- scanLine `M.unsafeRead` (idx - 2)-    e <- scanLine `M.unsafeRead` (idx - 1)--    (scanLine `M.unsafeWrite` (idx + 0)) r-    (scanLine `M.unsafeWrite` (idx + 1)) g-    (scanLine `M.unsafeWrite` (idx + 2)) b-    (scanLine `M.unsafeWrite` (idx + 3)) e--oldStyleRLE :: L.ByteString -> Int -> M.STVector s Word8-            -> HDRReader s Int-oldStyleRLE inputData initialIdx scanLine = inner initialIdx 0 0-  where maxOutput = M.length scanLine-        maxInput = fromIntegral $ L.length inputData--        inner readIdx writeIdx _-            | readIdx >= maxInput || writeIdx >= maxOutput = pure readIdx-        inner readIdx writeIdx shift = do-          let color@(RGBE r g b e) = unpackColor inputData readIdx-              isRun = r == 1 && g == 1 && b == 1--          if not isRun-            then do-              lift $ storeColor scanLine writeIdx color-              inner (readIdx + 4) (writeIdx + 4) 0-         -            else do-              let count = fromIntegral e .<<. shift-              lift $ forM_ [0 .. count] $ \i -> copyPrevColor scanLine (writeIdx + 4 * i)-              inner (readIdx + 4) (writeIdx + 4 * count) (shift + 8)--newStyleRLE :: L.ByteString -> Int -> M.STVector s Word8-            -> HDRReader s Int-newStyleRLE inputData initialIdx scanline = foldM inner initialIdx [0 .. 3]-  where dataAt idx-            | fromIntegral idx >= maxInput = throwE $ "Read index out of bound (" ++ show idx ++ ")"-            | otherwise = pure $ L.index inputData (fromIntegral idx)--        maxOutput = M.length scanline-        maxInput = fromIntegral $ L.length inputData-        stride = 4---        strideSet count destIndex _ | endIndex > maxOutput + stride =-          throwE $ "Out of bound HDR scanline " ++ show endIndex ++ " (max " ++ show maxOutput ++ ")"-            where endIndex = destIndex + count * stride-        strideSet count destIndex val = aux destIndex count-            where aux i 0 =  pure i-                  aux i c = do-                    lift $ (scanline .<-. i) val-                    aux (i + stride) (c - 1)---        strideCopy _ count destIndex-            | writeEndBound > maxOutput + stride = throwE "Out of bound HDR scanline"-                where writeEndBound = destIndex + count * stride-        strideCopy sourceIndex count destIndex = aux sourceIndex destIndex count-          where aux _ j 0 = pure j-                aux i j c = do-                    val <- dataAt i-                    lift $ (scanline .<-. j) val-                    aux (i + 1) (j + stride) (c - 1)--        inner readIdx writeIdx-            | readIdx >= maxInput || writeIdx >= maxOutput = pure readIdx-        inner readIdx writeIdx = do-          code <- dataAt readIdx-          if code > 128-            then do-              let repeatCount = fromIntegral code .&. 0x7F-              newVal <- dataAt $ readIdx + 1-              endIndex <- strideSet repeatCount writeIdx newVal-              inner (readIdx + 2) endIndex --            else do-              let iCode = fromIntegral code-              endIndex <- strideCopy (readIdx + 1) iCode writeIdx-              inner (readIdx + iCode + 1) endIndex--instance Binary RadianceHeader where-    get = decodeHeader-    put hdr = do-        putByteString radianceFileSignature-        putByteString $ BC.pack "FORMAT="-        put $ radianceFormat hdr-        let sizeString =-              BC.pack $ "\n\n-Y " ++ show (radianceHeight hdr)-                        ++ " +X " ++ show (radianceWidth hdr) ++ "\n"-        putByteString sizeString-        putLazyByteString $ radianceData hdr---decodeHeader :: Get RadianceHeader-decodeHeader = do-    sig <- getByteString $ B.length radianceFileSignature-    when (sig /= radianceFileSignature)-         (fail "Invalid radiance file signature")--    infos <- decodeInfos-    let formatKey = BC.pack "FORMAT"-    case partition (\(k,_) -> k /= formatKey) infos of-      (_, []) -> fail "No radiance format specified"-      (info, [(_, formatString)]) ->-        case runGet get $ L.fromChunks [formatString] of-          Left err -> fail err-          Right format -> do-              (n1, n2, b) <- (,,) <$> decodeNum-                                  <*> decodeNum-                                  <*> getRemainingBytes-              return . RadianceHeader info format n1 n2 $ L.fromChunks [b]--      _ -> fail "Multiple radiance format specified"--toFloat :: RGBE -> PixelRGBF-toFloat (RGBE r g b e) = PixelRGBF rf gf bf-  where f = encodeFloat 1 $ fromIntegral e - (128 + 8)-        rf = (fromIntegral r + 0.0) * f-        gf = (fromIntegral g + 0.0) * f-        bf = (fromIntegral b + 0.0) * f--encodeScanlineColor :: M.STVector s Word8-                    -> M.STVector s Word8-                    -> Int-                    -> ST s Int-encodeScanlineColor vec outVec outIdx = do-    val <- vec `M.unsafeRead` 0-    runLength 1 0 val 1 outIdx-  where maxIndex = M.length vec--        pushRun len val at = do-            (outVec `M.unsafeWrite` at) $ fromIntegral $ len .|. 0x80-            (outVec `M.unsafeWrite` (at + 1)) val-            return $ at + 2--        pushData start len at = do-            (outVec `M.unsafeWrite` at) $ fromIntegral len-            let first = start - len-                end = start - 1-                offset = at - first + 1-            forM_ [first .. end] $ \i -> do-                v <- vec `M.unsafeRead` i-                (outVec `M.unsafeWrite` (offset + i)) v--            return $ at + len + 1--        -- End of scanline, empty the thing-        runLength run cpy prev idx at | idx >= maxIndex =-            case (run, cpy) of-                (0, 0) -> pure at-                (0, n) -> pushData idx n at-                (n, 0) -> pushRun n prev at-                (_, _) -> error "HDR - Run length algorithm is wrong"--        -- full runlength, we must write the packet-        runLength r@127   _ prev idx at = do-            val <- vec `M.unsafeRead` idx-            pushRun r prev at >>=-                runLength 1 0 val (idx + 1)--        -- full copy, we must write the packet-        runLength   _ c@127    _ idx at = do-            val <- vec `M.unsafeRead` idx-            pushData idx c at >>=-                runLength 1 0 val (idx + 1)--        runLength n 0 prev idx at = do-            val <- vec `M.unsafeRead` idx-            case val == prev of-               True -> runLength (n + 1) 0 prev (idx + 1) at-               False | n < 4 -> runLength 0 (n + 1) val (idx + 1) at-               False ->-                    pushRun n prev at >>=-                        runLength 1 0 val (idx + 1)--        runLength 0 n prev idx at = do-            val <- vec `M.unsafeRead` idx-            if val /= prev-               then runLength 0 (n + 1) val (idx + 1) at-               else-                pushData (idx - 1) (n - 1) at >>=-                    runLength (2 :: Int) 0 val (idx + 1)--        runLength _ _ _ _ _ =-            error "HDR RLE inconsistent state"---- | Write an High dynamic range image into a radiance--- image file on disk.-writeHDR :: FilePath -> Image PixelRGBF -> IO ()-writeHDR filename img = L.writeFile filename $ encodeHDR img---- | Write a RLE encoded High dynamic range image into a radiance--- image file on disk.-writeRLENewStyleHDR :: FilePath -> Image PixelRGBF -> IO ()-writeRLENewStyleHDR filename img =-    L.writeFile filename $ encodeRLENewStyleHDR img---- | Encode an High dynamic range image into a radiance image--- file format.--- Alias for encodeRawHDR-encodeHDR :: Image PixelRGBF -> L.ByteString-encodeHDR = encodeRawHDR---- | Encode an High dynamic range image into a radiance image--- file format. without compression-encodeRawHDR :: Image PixelRGBF -> L.ByteString-encodeRawHDR pic = encode descriptor-  where-    newImage = pixelMap rgbeInRgba pic-    -- we are cheating to death here, the layout we want-    -- correspond to the layout of pixelRGBA8, so we-    -- convert-    rgbeInRgba pixel = PixelRGBA8 r g b e-      where RGBE r g b e = toRGBE pixel--    descriptor = RadianceHeader-        { radianceInfos = []-        , radianceFormat = FormatRGBE-        , radianceHeight = imageHeight pic-        , radianceWidth  = imageWidth pic-        , radianceData = L.fromChunks [toByteString $ imageData newImage]-        }----- | Encode an High dynamic range image into a radiance image--- file format using a light RLE compression. Some problems--- seem to arise with some image viewer.-encodeRLENewStyleHDR :: Image PixelRGBF -> L.ByteString-encodeRLENewStyleHDR pic = encode $ runST $ do-    let w = imageWidth pic-        h = imageHeight pic--    scanLineR <- M.new w :: ST s (M.STVector s Word8)-    scanLineG <- M.new w-    scanLineB <- M.new w-    scanLineE <- M.new w--    encoded <--        forM [0 .. h - 1] $ \line -> do-            buff <- M.new $ w * 4 + w `div` 127 + 2-            let columner col | col >= w = return ()-                columner col = do-                      let RGBE r g b e = toRGBE $ pixelAt pic col line-                      (scanLineR `M.unsafeWrite` col) r-                      (scanLineG `M.unsafeWrite` col) g-                      (scanLineB `M.unsafeWrite` col) b-                      (scanLineE `M.unsafeWrite` col) e--                      columner (col + 1)--            columner 0--            (buff `M.unsafeWrite` 0) 2-            (buff `M.unsafeWrite` 1) 2-            (buff `M.unsafeWrite` 2) $ fromIntegral ((w .>>. 8) .&. 0xFF)-            (buff `M.unsafeWrite` 3) $ fromIntegral (w .&. 0xFF)--            i1 <- encodeScanlineColor scanLineR buff 4        -            i2 <- encodeScanlineColor scanLineG buff i1-            i3 <- encodeScanlineColor scanLineB buff i2-            endIndex <- encodeScanlineColor scanLineE buff i3--            (\v -> blitVector v 0 endIndex) <$> V.unsafeFreeze buff--    pure RadianceHeader-        { radianceInfos = []-        , radianceFormat = FormatRGBE-        , radianceHeight = h-        , radianceWidth  = w-        , radianceData = L.fromChunks encoded -        }-    --decodeRadiancePicture :: RadianceHeader -> HDRReader s (MutableImage s PixelRGBF)-decodeRadiancePicture hdr = do-    let width = abs $ radianceWidth hdr-        height = abs $ radianceHeight hdr-        packedData = radianceData hdr--    scanLine <- lift $ M.new $ width * 4-    resultBuffer <- lift $ M.new $ width * height * 3--    let scanLineImage = MutableImage-                      { mutableImageWidth = width-                      , mutableImageHeight = 1-                      , mutableImageData = scanLine-                      }--        finalImage = MutableImage-                   { mutableImageWidth = width-                   , mutableImageHeight = height-                   , mutableImageData = resultBuffer-                   }--    let scanLineExtractor readIdx line = do-          let color = unpackColor packedData readIdx-              inner | isNewRunLengthMarker color = do-                          let calcSize = checkLineLength color-                          when (calcSize /= width)-                               (throwE "Invalid sanline size")-                          pure $ \idx -> newStyleRLE packedData (idx + 4)-                    | otherwise = pure $ oldStyleRLE packedData-          f <- inner-          newRead <- f readIdx scanLine-          forM_ [0 .. width - 1] $ \i -> do-              -- mokay, it's a hack, but I don't want to define a-              -- pixel instance of RGBE...-              PixelRGBA8 r g b e <- lift $ readPixel scanLineImage i 0-              lift $ writePixel finalImage i line . toFloat $ RGBE r g b e--          return newRead--    foldM_ scanLineExtractor 0 [0 .. height - 1]--    return finalImage-+{-# LANGUAGE CPP #-}
+{-# LANGUAGE TypeFamilies #-}
+{-# LANGUAGE TupleSections   #-}
+-- | Module dedicated of Radiance file decompression (.hdr or .pic) file.
+-- Radiance file format is used for High dynamic range imaging.
+module Codec.Picture.HDR( decodeHDR
+                        , decodeHDRWithMetadata
+                        , encodeHDR
+                        , encodeRawHDR
+                        , encodeRLENewStyleHDR
+                        , writeHDR
+                        , writeRLENewStyleHDR
+                        ) where
+
+#if !MIN_VERSION_base(4,8,0)
+import Control.Applicative( pure, (<*>), (<$>) )
+#endif
+
+import Data.Bits( Bits, (.&.), (.|.), unsafeShiftL, unsafeShiftR )
+import Data.Char( ord, chr, isDigit )
+import Data.Word( Word8 )
+
+#if !MIN_VERSION_base(4,11,0)
+import Data.Monoid( (<>) )
+#endif
+
+import Control.Monad( when, foldM, foldM_, forM, forM_, unless )
+import Control.Monad.Trans.Class( lift )
+import qualified Data.ByteString as B
+import qualified Data.ByteString.Lazy as L
+import qualified Data.ByteString.Char8 as BC
+
+import Data.List( partition )
+import Data.Binary( Binary( .. ), encode )
+import Data.Binary.Get( Get, getByteString, getWord8 )
+import Data.Binary.Put( putByteString, putLazyByteString )
+
+import Control.Monad.ST( ST, runST )
+import Foreign.Storable ( Storable )
+import Control.Monad.Primitive ( PrimState, PrimMonad )
+import qualified Data.Vector.Storable as V
+import qualified Data.Vector.Storable.Mutable as M
+
+import Codec.Picture.Metadata( Metadatas
+                             , SourceFormat( SourceHDR )
+                             , basicMetadata )
+import Codec.Picture.InternalHelper
+import Codec.Picture.Types
+import Codec.Picture.VectorByteConversion
+
+#if MIN_VERSION_transformers(0, 4, 0)
+import Control.Monad.Trans.Except( ExceptT, throwE, runExceptT )
+#else
+-- Transfomers 0.3 compat
+import Control.Monad.Trans.Error( Error, ErrorT, throwError, runErrorT )
+
+type ExceptT = ErrorT
+
+throwE :: (Monad m, Error e) => e -> ErrorT e m a
+throwE = throwError
+
+runExceptT :: ErrorT e m a -> m (Either e a)
+runExceptT = runErrorT
+#endif
+
+{-# INLINE (.<<.) #-}
+(.<<.), (.>>.) :: (Bits a) => a -> Int -> a
+(.<<.) = unsafeShiftL
+(.>>.) = unsafeShiftR
+
+{-# INLINE (.<-.) #-}
+(.<-.) :: (PrimMonad m, Storable a)
+       => M.STVector (PrimState m) a -> Int -> a -> m ()
+(.<-.) = M.write 
+         {-M.unsafeWrite-}
+
+type HDRReader s a = ExceptT String (ST s) a
+
+data RGBE = RGBE !Word8 !Word8 !Word8 !Word8
+
+instance Binary RGBE where
+    put (RGBE r g b e) = put r >> put g >> put b >> put e
+    get = RGBE <$> get <*> get <*> get <*> get
+
+checkLineLength :: RGBE -> Int
+checkLineLength (RGBE _ _ a b) =
+    (fromIntegral a .<<. 8) .|. fromIntegral b
+
+isNewRunLengthMarker :: RGBE -> Bool
+isNewRunLengthMarker (RGBE 2 2 _ _) = True
+isNewRunLengthMarker _ = False
+
+data RadianceFormat =
+      FormatRGBE
+    | FormatXYZE
+
+radiance32bitRleRGBEFormat, radiance32bitRleXYZEFromat :: B.ByteString
+radiance32bitRleRGBEFormat = BC.pack "32-bit_rle_rgbe"
+radiance32bitRleXYZEFromat = BC.pack "32-bit_rle_xyze"
+
+instance Binary RadianceFormat where
+  put FormatRGBE = putByteString radiance32bitRleRGBEFormat
+  put FormatXYZE = putByteString radiance32bitRleXYZEFromat
+
+  get = getByteString (B.length radiance32bitRleRGBEFormat) >>= format
+    where format sig
+            | sig == radiance32bitRleRGBEFormat = pure FormatRGBE
+            | sig == radiance32bitRleXYZEFromat = pure FormatXYZE
+            | otherwise = fail "Unrecognized Radiance format"
+
+toRGBE :: PixelRGBF -> RGBE
+toRGBE (PixelRGBF r g b)
+    | d <= 1e-32 = RGBE 0 0 0 0
+    | otherwise = RGBE (fix r) (fix g) (fix b) (fromIntegral $ e + 128)
+  where d = maximum [r, g, b]
+        e = exponent d
+        coeff = significand d *  255.9999 / d
+        fix v = truncate $ v * coeff
+
+
+dropUntil :: Word8 -> Get ()
+dropUntil c = getWord8 >>= inner
+  where inner val | val == c = pure ()
+        inner _ = getWord8 >>= inner
+
+getUntil :: (Word8 -> Bool) -> B.ByteString -> Get B.ByteString
+getUntil f initialAcc = getWord8 >>= inner initialAcc
+  where inner acc c | f c = pure acc
+        inner acc c = getWord8 >>= inner (B.snoc acc c)
+
+data RadianceHeader = RadianceHeader
+  { radianceInfos :: [(B.ByteString, B.ByteString)]
+  , radianceFormat :: RadianceFormat
+  , radianceHeight :: !Int
+  , radianceWidth  :: !Int
+  , radianceData   :: L.ByteString
+  }
+
+radianceFileSignature :: B.ByteString
+radianceFileSignature = BC.pack "#?RADIANCE\n"
+
+unpackColor :: L.ByteString -> Int -> RGBE
+unpackColor str idx = RGBE (at 0) (at 1) (at 2) (at 3)
+  where at n = L.index str . fromIntegral $ idx + n
+
+storeColor :: M.STVector s Word8 -> Int -> RGBE -> ST s ()
+storeColor vec idx (RGBE r g b e) = do
+    (vec .<-. (idx + 0)) r
+    (vec .<-. (idx + 1)) g
+    (vec .<-. (idx + 2)) b
+    (vec .<-. (idx + 3)) e
+
+parsePair :: Char -> Get (B.ByteString, B.ByteString)
+parsePair firstChar = do
+    let eol c = c == fromIntegral (ord '\n')
+    line <- getUntil eol B.empty
+    case BC.split '=' line of
+      [] -> pure (BC.singleton firstChar, B.empty)
+      [val] -> pure (BC.singleton firstChar, val)
+      [key, val] -> pure (BC.singleton firstChar <> key, val)
+      (key : vals) -> pure (BC.singleton firstChar <> key, B.concat vals)
+
+decodeInfos :: Get [(B.ByteString, B.ByteString)]
+decodeInfos = do
+    char <- getChar8
+    case char of
+      -- comment
+      '#' -> dropUntil (fromIntegral $ ord '\n') >> decodeInfos
+      -- end of header, no more information
+      '\n' -> pure []
+      -- Classical parsing
+      c -> (:) <$> parsePair c <*> decodeInfos
+
+
+-- | Decode an HDR (radiance) image, the resulting image can be:
+--
+--  * 'ImageRGBF'
+--
+decodeHDR :: B.ByteString -> Either String DynamicImage
+decodeHDR = fmap fst . decodeHDRWithMetadata
+
+-- | Equivalent to decodeHDR but with aditional metadatas.
+decodeHDRWithMetadata :: B.ByteString -> Either String (DynamicImage, Metadatas)
+decodeHDRWithMetadata str = runST $ runExceptT $
+  case runGet decodeHeader $ L.fromChunks [str] of
+    Left err -> throwE err
+    Right rez ->
+      let meta = basicMetadata SourceHDR (abs $ radianceWidth rez) (abs $ radianceHeight rez) in
+      (, meta) . ImageRGBF <$> (decodeRadiancePicture rez >>= lift . unsafeFreezeImage)
+
+getChar8 :: Get Char
+getChar8 = chr . fromIntegral <$> getWord8
+
+isSign :: Char -> Bool
+isSign c = c == '+' || c == '-'
+
+isAxisLetter :: Char -> Bool
+isAxisLetter c = c == 'X' || c == 'Y'
+
+decodeNum :: Get Int
+decodeNum = do
+    sign <- getChar8
+    letter <- getChar8
+    space <- getChar8
+
+    unless (isSign sign && isAxisLetter letter && space == ' ')
+           (fail "Invalid radiance size declaration")
+
+    let numDec acc c | isDigit c =
+            getChar8 >>= numDec (acc * 10 + ord c - ord '0')
+        numDec acc _
+            | sign == '-' = pure $ negate acc
+            | otherwise = pure acc
+
+    getChar8 >>= numDec 0
+
+copyPrevColor :: M.STVector s Word8 -> Int -> ST s ()
+copyPrevColor scanLine idx = do
+    r <- scanLine `M.unsafeRead` (idx - 4)
+    g <- scanLine `M.unsafeRead` (idx - 3)
+    b <- scanLine `M.unsafeRead` (idx - 2)
+    e <- scanLine `M.unsafeRead` (idx - 1)
+
+    (scanLine `M.unsafeWrite` (idx + 0)) r
+    (scanLine `M.unsafeWrite` (idx + 1)) g
+    (scanLine `M.unsafeWrite` (idx + 2)) b
+    (scanLine `M.unsafeWrite` (idx + 3)) e
+
+oldStyleRLE :: L.ByteString -> Int -> M.STVector s Word8
+            -> HDRReader s Int
+oldStyleRLE inputData initialIdx scanLine = inner initialIdx 0 0
+  where maxOutput = M.length scanLine
+        maxInput = fromIntegral $ L.length inputData
+
+        inner readIdx writeIdx _
+            | readIdx >= maxInput || writeIdx >= maxOutput = pure readIdx
+        inner readIdx writeIdx shift = do
+          let color@(RGBE r g b e) = unpackColor inputData readIdx
+              isRun = r == 1 && g == 1 && b == 1
+
+          if not isRun
+            then do
+              lift $ storeColor scanLine writeIdx color
+              inner (readIdx + 4) (writeIdx + 4) 0
+         
+            else do
+              let count = fromIntegral e .<<. shift
+              lift $ forM_ [0 .. count] $ \i -> copyPrevColor scanLine (writeIdx + 4 * i)
+              inner (readIdx + 4) (writeIdx + 4 * count) (shift + 8)
+
+newStyleRLE :: L.ByteString -> Int -> M.STVector s Word8
+            -> HDRReader s Int
+newStyleRLE inputData initialIdx scanline = foldM inner initialIdx [0 .. 3]
+  where dataAt idx
+            | fromIntegral idx >= maxInput = throwE $ "Read index out of bound (" ++ show idx ++ ")"
+            | otherwise = pure $ L.index inputData (fromIntegral idx)
+
+        maxOutput = M.length scanline
+        maxInput = fromIntegral $ L.length inputData
+        stride = 4
+
+
+        strideSet count destIndex _ | endIndex > maxOutput + stride =
+          throwE $ "Out of bound HDR scanline " ++ show endIndex ++ " (max " ++ show maxOutput ++ ")"
+            where endIndex = destIndex + count * stride
+        strideSet count destIndex val = aux destIndex count
+            where aux i 0 =  pure i
+                  aux i c = do
+                    lift $ (scanline .<-. i) val
+                    aux (i + stride) (c - 1)
+
+
+        strideCopy _ count destIndex
+            | writeEndBound > maxOutput + stride = throwE "Out of bound HDR scanline"
+                where writeEndBound = destIndex + count * stride
+        strideCopy sourceIndex count destIndex = aux sourceIndex destIndex count
+          where aux _ j 0 = pure j
+                aux i j c = do
+                    val <- dataAt i
+                    lift $ (scanline .<-. j) val
+                    aux (i + 1) (j + stride) (c - 1)
+
+        inner readIdx writeIdx
+            | readIdx >= maxInput || writeIdx >= maxOutput = pure readIdx
+        inner readIdx writeIdx = do
+          code <- dataAt readIdx
+          if code > 128
+            then do
+              let repeatCount = fromIntegral code .&. 0x7F
+              newVal <- dataAt $ readIdx + 1
+              endIndex <- strideSet repeatCount writeIdx newVal
+              inner (readIdx + 2) endIndex 
+
+            else do
+              let iCode = fromIntegral code
+              endIndex <- strideCopy (readIdx + 1) iCode writeIdx
+              inner (readIdx + iCode + 1) endIndex
+
+instance Binary RadianceHeader where
+    get = decodeHeader
+    put hdr = do
+        putByteString radianceFileSignature
+        putByteString $ BC.pack "FORMAT="
+        put $ radianceFormat hdr
+        let sizeString =
+              BC.pack $ "\n\n-Y " ++ show (radianceHeight hdr)
+                        ++ " +X " ++ show (radianceWidth hdr) ++ "\n"
+        putByteString sizeString
+        putLazyByteString $ radianceData hdr
+
+
+decodeHeader :: Get RadianceHeader
+decodeHeader = do
+    sig <- getByteString $ B.length radianceFileSignature
+    when (sig /= radianceFileSignature)
+         (fail "Invalid radiance file signature")
+
+    infos <- decodeInfos
+    let formatKey = BC.pack "FORMAT"
+    case partition (\(k,_) -> k /= formatKey) infos of
+      (_, []) -> fail "No radiance format specified"
+      (info, [(_, formatString)]) ->
+        case runGet get $ L.fromChunks [formatString] of
+          Left err -> fail err
+          Right format -> do
+              (n1, n2, b) <- (,,) <$> decodeNum
+                                  <*> decodeNum
+                                  <*> getRemainingBytes
+              return . RadianceHeader info format n1 n2 $ L.fromChunks [b]
+
+      _ -> fail "Multiple radiance format specified"
+
+toFloat :: RGBE -> PixelRGBF
+toFloat (RGBE r g b e) = PixelRGBF rf gf bf
+  where f = encodeFloat 1 $ fromIntegral e - (128 + 8)
+        rf = (fromIntegral r + 0.0) * f
+        gf = (fromIntegral g + 0.0) * f
+        bf = (fromIntegral b + 0.0) * f
+
+encodeScanlineColor :: M.STVector s Word8
+                    -> M.STVector s Word8
+                    -> Int
+                    -> ST s Int
+encodeScanlineColor vec outVec outIdx = do
+    val <- vec `M.unsafeRead` 0
+    runLength 1 0 val 1 outIdx
+  where maxIndex = M.length vec
+
+        pushRun len val at = do
+            (outVec `M.unsafeWrite` at) $ fromIntegral $ len .|. 0x80
+            (outVec `M.unsafeWrite` (at + 1)) val
+            return $ at + 2
+
+        pushData start len at = do
+            (outVec `M.unsafeWrite` at) $ fromIntegral len
+            let first = start - len
+                end = start - 1
+                offset = at - first + 1
+            forM_ [first .. end] $ \i -> do
+                v <- vec `M.unsafeRead` i
+                (outVec `M.unsafeWrite` (offset + i)) v
+
+            return $ at + len + 1
+
+        -- End of scanline, empty the thing
+        runLength run cpy prev idx at | idx >= maxIndex =
+            case (run, cpy) of
+                (0, 0) -> pure at
+                (0, n) -> pushData idx n at
+                (n, 0) -> pushRun n prev at
+                (_, _) -> error "HDR - Run length algorithm is wrong"
+
+        -- full runlength, we must write the packet
+        runLength r@127   _ prev idx at = do
+            val <- vec `M.unsafeRead` idx
+            pushRun r prev at >>=
+                runLength 1 0 val (idx + 1)
+
+        -- full copy, we must write the packet
+        runLength   _ c@127    _ idx at = do
+            val <- vec `M.unsafeRead` idx
+            pushData idx c at >>=
+                runLength 1 0 val (idx + 1)
+
+        runLength n 0 prev idx at = do
+            val <- vec `M.unsafeRead` idx
+            case val == prev of
+               True -> runLength (n + 1) 0 prev (idx + 1) at
+               False | n < 4 -> runLength 0 (n + 1) val (idx + 1) at
+               False ->
+                    pushRun n prev at >>=
+                        runLength 1 0 val (idx + 1)
+
+        runLength 0 n prev idx at = do
+            val <- vec `M.unsafeRead` idx
+            if val /= prev
+               then runLength 0 (n + 1) val (idx + 1) at
+               else
+                pushData (idx - 1) (n - 1) at >>=
+                    runLength (2 :: Int) 0 val (idx + 1)
+
+        runLength _ _ _ _ _ =
+            error "HDR RLE inconsistent state"
+
+-- | Write an High dynamic range image into a radiance
+-- image file on disk.
+writeHDR :: FilePath -> Image PixelRGBF -> IO ()
+writeHDR filename img = L.writeFile filename $ encodeHDR img
+
+-- | Write a RLE encoded High dynamic range image into a radiance
+-- image file on disk.
+writeRLENewStyleHDR :: FilePath -> Image PixelRGBF -> IO ()
+writeRLENewStyleHDR filename img =
+    L.writeFile filename $ encodeRLENewStyleHDR img
+
+-- | Encode an High dynamic range image into a radiance image
+-- file format.
+-- Alias for encodeRawHDR
+encodeHDR :: Image PixelRGBF -> L.ByteString
+encodeHDR = encodeRawHDR
+
+-- | Encode an High dynamic range image into a radiance image
+-- file format. without compression
+encodeRawHDR :: Image PixelRGBF -> L.ByteString
+encodeRawHDR pic = encode descriptor
+  where
+    newImage = pixelMap rgbeInRgba pic
+    -- we are cheating to death here, the layout we want
+    -- correspond to the layout of pixelRGBA8, so we
+    -- convert
+    rgbeInRgba pixel = PixelRGBA8 r g b e
+      where RGBE r g b e = toRGBE pixel
+
+    descriptor = RadianceHeader
+        { radianceInfos = []
+        , radianceFormat = FormatRGBE
+        , radianceHeight = imageHeight pic
+        , radianceWidth  = imageWidth pic
+        , radianceData = L.fromChunks [toByteString $ imageData newImage]
+        }
+
+
+-- | Encode an High dynamic range image into a radiance image
+-- file format using a light RLE compression. Some problems
+-- seem to arise with some image viewer.
+encodeRLENewStyleHDR :: Image PixelRGBF -> L.ByteString
+encodeRLENewStyleHDR pic = encode $ runST $ do
+    let w = imageWidth pic
+        h = imageHeight pic
+
+    scanLineR <- M.new w :: ST s (M.STVector s Word8)
+    scanLineG <- M.new w
+    scanLineB <- M.new w
+    scanLineE <- M.new w
+
+    encoded <-
+        forM [0 .. h - 1] $ \line -> do
+            buff <- M.new $ w * 4 + w `div` 127 + 2
+            let columner col | col >= w = return ()
+                columner col = do
+                      let RGBE r g b e = toRGBE $ pixelAt pic col line
+                      (scanLineR `M.unsafeWrite` col) r
+                      (scanLineG `M.unsafeWrite` col) g
+                      (scanLineB `M.unsafeWrite` col) b
+                      (scanLineE `M.unsafeWrite` col) e
+
+                      columner (col + 1)
+
+            columner 0
+
+            (buff `M.unsafeWrite` 0) 2
+            (buff `M.unsafeWrite` 1) 2
+            (buff `M.unsafeWrite` 2) $ fromIntegral ((w .>>. 8) .&. 0xFF)
+            (buff `M.unsafeWrite` 3) $ fromIntegral (w .&. 0xFF)
+
+            i1 <- encodeScanlineColor scanLineR buff 4        
+            i2 <- encodeScanlineColor scanLineG buff i1
+            i3 <- encodeScanlineColor scanLineB buff i2
+            endIndex <- encodeScanlineColor scanLineE buff i3
+
+            (\v -> blitVector v 0 endIndex) <$> V.unsafeFreeze buff
+
+    pure RadianceHeader
+        { radianceInfos = []
+        , radianceFormat = FormatRGBE
+        , radianceHeight = h
+        , radianceWidth  = w
+        , radianceData = L.fromChunks encoded 
+        }
+    
+
+decodeRadiancePicture :: RadianceHeader -> HDRReader s (MutableImage s PixelRGBF)
+decodeRadiancePicture hdr = do
+    let width = abs $ radianceWidth hdr
+        height = abs $ radianceHeight hdr
+        packedData = radianceData hdr
+
+    scanLine <- lift $ M.new $ width * 4
+    resultBuffer <- lift $ M.new $ width * height * 3
+
+    let scanLineImage = MutableImage
+                      { mutableImageWidth = width
+                      , mutableImageHeight = 1
+                      , mutableImageData = scanLine
+                      }
+
+        finalImage = MutableImage
+                   { mutableImageWidth = width
+                   , mutableImageHeight = height
+                   , mutableImageData = resultBuffer
+                   }
+
+    let scanLineExtractor readIdx line = do
+          let color = unpackColor packedData readIdx
+              inner | isNewRunLengthMarker color = do
+                          let calcSize = checkLineLength color
+                          when (calcSize /= width)
+                               (throwE "Invalid sanline size")
+                          pure $ \idx -> newStyleRLE packedData (idx + 4)
+                    | otherwise = pure $ oldStyleRLE packedData
+          f <- inner
+          newRead <- f readIdx scanLine
+          forM_ [0 .. width - 1] $ \i -> do
+              -- mokay, it's a hack, but I don't want to define a
+              -- pixel instance of RGBE...
+              PixelRGBA8 r g b e <- lift $ readPixel scanLineImage i 0
+              lift $ writePixel finalImage i line . toFloat $ RGBE r g b e
+
+          return newRead
+
+    foldM_ scanLineExtractor 0 [0 .. height - 1]
+
+    return finalImage
+
src/Codec/Picture/InternalHelper.hs view
@@ -1,51 +1,32 @@-{-# LANGUAGE CPP #-}-module Codec.Picture.InternalHelper ( runGet-                                    , runGetStrict-                                    , decode-                                    , getRemainingBytes-                                    , getRemainingLazyBytes ) where--import qualified Data.ByteString as B-import qualified Data.ByteString.Lazy as L-import Data.Binary( Binary( get ) )-import Data.Binary.Get( Get-                      , getRemainingLazyByteString-                      )-import qualified Data.Binary.Get as G--#if MIN_VERSION_binary(0,6,4)-#else-import Control.Applicative( (<$>) )-import qualified Control.Exception as E--- I feel so dirty. :(-import System.IO.Unsafe( unsafePerformIO )-#endif--decode :: (Binary a) => B.ByteString -> Either String a-decode = runGetStrict get--runGet :: Get a -> L.ByteString -> Either String a-#if MIN_VERSION_binary(0,6,4)-runGet act = unpack . G.runGetOrFail act-    where unpack (Left (_, _, str)) = Left str-          unpack (Right (_, _, element)) = Right element-#else-runGet act str = unsafePerformIO $ E.catch-    (Right <$> E.evaluate (G.runGet act str))-    (\msg -> return . Left $ show (msg :: E.SomeException))-#endif--runGetStrict :: Get a -> B.ByteString -> Either String a-runGetStrict act buffer = runGet act $ L.fromChunks [buffer]--getRemainingBytes :: Get B.ByteString-getRemainingBytes = do-    rest <- getRemainingLazyByteString -    return $ case L.toChunks rest of-        [] -> B.empty-        [a] -> a-        lst -> B.concat lst--getRemainingLazyBytes :: Get L.ByteString-getRemainingLazyBytes = getRemainingLazyByteString -+{-# LANGUAGE CPP #-}
+module Codec.Picture.InternalHelper ( runGet
+                                    , runGetStrict
+                                    , decode
+                                    , getRemainingBytes
+                                    , getRemainingLazyBytes ) where
+
+import qualified Data.ByteString as B
+import qualified Data.ByteString.Lazy as L
+import Data.Binary( Binary( get ) )
+import Data.Binary.Get( Get
+                      , getRemainingLazyByteString
+                      )
+import qualified Data.Binary.Get as G
+
+decode :: (Binary a) => B.ByteString -> Either String a
+decode = runGetStrict get
+
+runGet :: Get a -> L.ByteString -> Either String a
+runGet act = unpack . G.runGetOrFail act
+    where unpack (Left (_, _, str)) = Left str
+          unpack (Right (_, _, element)) = Right element
+
+runGetStrict :: Get a -> B.ByteString -> Either String a
+runGetStrict act buffer = runGet act $ L.fromChunks [buffer]
+
+getRemainingBytes :: Get B.ByteString
+getRemainingBytes = L.toStrict <$> getRemainingLazyByteString
+
+getRemainingLazyBytes :: Get L.ByteString
+getRemainingLazyBytes = getRemainingLazyByteString
+
src/Codec/Picture/Jpg.hs view
@@ -31,7 +31,9 @@ import Control.Monad.Trans.RWS.Strict( RWS, modify, tell, gets, execRWS )
 
 import Data.Bits( (.|.), unsafeShiftL )
+#if !MIN_VERSION_base(4,11,0)
 import Data.Monoid( (<>) )
+#endif
 import Data.Int( Int16, Int32 )
 import Data.Word(Word8, Word32)
 import Data.Binary( Binary(..), encode )
@@ -52,14 +54,14 @@ import Codec.Picture.Metadata( Metadatas
                              , SourceFormat( SourceJpeg )
                              , basicMetadata )
-import Codec.Picture.Tiff.Types
-import Codec.Picture.Tiff.Metadata
-import Codec.Picture.Jpg.Types
-import Codec.Picture.Jpg.Common
-import Codec.Picture.Jpg.Progressive
-import Codec.Picture.Jpg.DefaultTable
-import Codec.Picture.Jpg.FastDct
-import Codec.Picture.Jpg.Metadata
+import Codec.Picture.Tiff.Internal.Types
+import Codec.Picture.Tiff.Internal.Metadata
+import Codec.Picture.Jpg.Internal.Types
+import Codec.Picture.Jpg.Internal.Common
+import Codec.Picture.Jpg.Internal.Progressive
+import Codec.Picture.Jpg.Internal.DefaultTable
+import Codec.Picture.Jpg.Internal.FastDct
+import Codec.Picture.Jpg.Internal.Metadata
 
 quantize :: MacroBlock Int16 -> MutableMacroBlock s Int32
          -> ST s (MutableMacroBlock s Int32)
@@ -309,7 +311,7 @@         scanSpecifier scanCount scanSpec = do
             compMapping <- gets componentIndexMapping
             comp <- case lookup (componentSelector scanSpec) compMapping of
-                Nothing -> fail "Jpg decoding error - bad component selector in blob."
+                Nothing -> error "Jpg decoding error - bad component selector in blob."
                 Just v -> return v
             let maximumHuffmanTable = 4
                 dcIndex = min (maximumHuffmanTable - 1) 
@@ -326,7 +328,7 @@             frameInfo <- gets currentFrame
             blobId <- gets seenBlobs                   
             case frameInfo of
-              Nothing -> fail "Jpg decoding error - no previous frame"
+              Nothing -> error "Jpg decoding error - no previous frame"
               Just v -> do
                  let compDesc = jpgComponents v !! comp
                      compCount = length $ jpgComponents v
@@ -420,9 +422,16 @@   forM_ lst $ \(params, str) -> do
     let componentsInfo = V.fromList params
         compReader = initBoolStateJpg . B.concat $ L.toChunks str
-        maxiW = maximum [fst $ subSampling c | (c,_) <- params]
-        maxiH = maximum [snd $ subSampling c | (c,_) <- params]
+        maxiSubSampW = maximum [fst $ subSampling c | (c,_) <- params]
+        maxiSubSampH = maximum [snd $ subSampling c | (c,_) <- params]
 
+        (maxiW, maxiH) = 
+            if length params > 1 then
+                (maximum [componentWidth c | (c,_) <- params], 
+                    maximum [componentHeight c | (c,_) <- params])
+            else
+                (maxiSubSampW, maxiSubSampH)
+
         imageBlockWidth = toBlockSize imgWidth
         imageBlockHeight = toBlockSize imgHeight
 
@@ -572,7 +581,7 @@        let (st, arr) = decodeBaseline
            jfifMeta = foldMap extractMetadatas $ app0JFifMarker st
            exifMeta = foldMap extractTiffMetadata $ app1ExifMarker st
-           meta = sizeMeta <> jfifMeta <> exifMeta
+           meta = jfifMeta <> exifMeta <> sizeMeta
        in
        (, meta) <$>
            dynamicOfColorSpace (colorSpaceOfState st) imgWidth imgHeight arr
@@ -580,7 +589,7 @@        let (st, arr) = decodeProgressive
            jfifMeta = foldMap extractMetadatas $ app0JFifMarker st
            exifMeta = foldMap extractTiffMetadata $ app1ExifMarker st
-           meta = sizeMeta <> jfifMeta <> exifMeta
+           meta = jfifMeta <> exifMeta <> sizeMeta
        in
        (, meta) <$>
            dynamicOfColorSpace (colorSpaceOfState st) imgWidth imgHeight arr
− src/Codec/Picture/Jpg/Common.hs
@@ -1,240 +0,0 @@-{-# LANGUAGE BangPatterns #-}
-{-# LANGUAGE TypeFamilies #-}
-{-# LANGUAGE CPP #-}
-module Codec.Picture.Jpg.Common
-    ( DctCoefficients
-    , JpgUnpackerParameter( .. )
-    , decodeInt
-    , dcCoefficientDecode
-    , deQuantize
-    , decodeRrrrSsss
-    , zigZagReorderForward 
-    , zigZagReorderForwardv
-    , zigZagReorder
-    , inverseDirectCosineTransform
-    , unpackInt
-    , unpackMacroBlock
-    , rasterMap
-    , decodeMacroBlock
-    , decodeRestartInterval
-    , toBlockSize
-    ) where
-
-#if !MIN_VERSION_base(4,8,0)
-import Control.Applicative( pure, (<$>) )
-#endif
-
-import Control.Monad( when )
-import Control.Monad.ST( ST, runST )
-import Data.Bits( unsafeShiftL, unsafeShiftR, (.&.) )
-import Data.Int( Int16, Int32 )
-import Data.Maybe( fromMaybe )
-import Data.Word( Word8 )
-import qualified Data.Vector.Storable as VS
-import qualified Data.Vector.Storable.Mutable as M
-import Foreign.Storable ( Storable )
-
-import Codec.Picture.Types
-import Codec.Picture.BitWriter
-import Codec.Picture.Jpg.Types
-import Codec.Picture.Jpg.FastIdct
-import Codec.Picture.Jpg.DefaultTable
-
--- | Same as for DcCoefficient, to provide nicer type signatures
-type DctCoefficients = DcCoefficient
-
-data JpgUnpackerParameter = JpgUnpackerParameter
-    { dcHuffmanTree        :: !HuffmanPackedTree
-    , acHuffmanTree        :: !HuffmanPackedTree
-    , componentIndex       :: {-# UNPACK #-} !Int
-    , restartInterval      :: {-# UNPACK #-} !Int
-    , componentWidth       :: {-# UNPACK #-} !Int
-    , componentHeight      :: {-# UNPACK #-} !Int
-    , subSampling          :: !(Int, Int)
-    , coefficientRange     :: !(Int, Int)
-    , successiveApprox     :: !(Int, Int)
-    , readerIndex          :: {-# UNPACK #-} !Int
-      -- | When in progressive mode, we can have many
-      -- color in a scan or only one. The indices changes
-      -- on this fact, when mixed, there is whole 
-      -- MCU for all color components, spanning multiple
-      -- block lines. With only one color component we use
-      -- the normal raster order.
-    , indiceVector         :: {-# UNPACK #-} !Int
-    , blockIndex           :: {-# UNPACK #-} !Int
-    , blockMcuX            :: {-# UNPACK #-} !Int
-    , blockMcuY            :: {-# UNPACK #-} !Int
-    }
-    deriving Show
-
-toBlockSize :: Int -> Int
-toBlockSize v = (v + 7) `div` 8
-
-decodeRestartInterval :: BoolReader s Int32
-decodeRestartInterval = return (-1) {-  do
-  bits <- replicateM 8 getNextBitJpg
-  if bits == replicate 8 True
-     then do
-         marker <- replicateM 8 getNextBitJpg
-         return $ packInt marker
-     else return (-1)
-        -}
-
-{-# INLINE decodeInt #-}
-decodeInt :: Int -> BoolReader s Int32
-decodeInt ssss = do
-    signBit <- getNextBitJpg
-    let dataRange = 1 `unsafeShiftL` fromIntegral (ssss - 1)
-        leftBitCount = ssss - 1
-    -- First following bits store the sign of the coefficient, and counted in
-    -- SSSS, so the bit count for the int, is ssss - 1
-    if signBit
-       then (\w -> dataRange + fromIntegral w) <$> unpackInt leftBitCount
-       else (\w -> 1 - dataRange * 2 + fromIntegral w) <$> unpackInt leftBitCount
-
-decodeRrrrSsss :: HuffmanPackedTree -> BoolReader s (Int, Int)
-decodeRrrrSsss tree = do
-    rrrrssss <- huffmanPackedDecode tree
-    let rrrr = (rrrrssss `unsafeShiftR` 4) .&. 0xF
-        ssss =  rrrrssss .&. 0xF
-    pure (fromIntegral rrrr, fromIntegral ssss)
-
-dcCoefficientDecode :: HuffmanPackedTree -> BoolReader s DcCoefficient
-dcCoefficientDecode dcTree = do
-    ssss <- huffmanPackedDecode dcTree
-    if ssss == 0
-       then return 0
-       else fromIntegral <$> decodeInt (fromIntegral ssss)
-
--- | Apply a quantization matrix to a macroblock
-{-# INLINE deQuantize #-}
-deQuantize :: MacroBlock Int16 -> MutableMacroBlock s Int16
-           -> ST s (MutableMacroBlock s Int16)
-deQuantize table block = update 0
-    where update 64 = return block
-          update i = do
-              val <- block `M.unsafeRead` i
-              let finalValue = val * (table `VS.unsafeIndex` i)
-              (block `M.unsafeWrite` i) finalValue
-              update $ i + 1
-
-inverseDirectCosineTransform :: MutableMacroBlock s Int16
-                             -> ST s (MutableMacroBlock s Int16)
-inverseDirectCosineTransform mBlock =
-    fastIdct mBlock >>= mutableLevelShift
-
-zigZagOrder :: MacroBlock Int
-zigZagOrder = makeMacroBlock $ concat
-    [[ 0, 1, 5, 6,14,15,27,28]
-    ,[ 2, 4, 7,13,16,26,29,42]
-    ,[ 3, 8,12,17,25,30,41,43]
-    ,[ 9,11,18,24,31,40,44,53]
-    ,[10,19,23,32,39,45,52,54]
-    ,[20,22,33,38,46,51,55,60]
-    ,[21,34,37,47,50,56,59,61]
-    ,[35,36,48,49,57,58,62,63]
-    ]
-
-zigZagReorderForwardv :: (Storable a, Num a) => VS.Vector a -> VS.Vector a
-zigZagReorderForwardv vec = runST $ do
-    v <- M.new 64
-    mv <- VS.thaw vec
-    zigZagReorderForward v mv >>= VS.freeze
-
-zigZagOrderForward :: MacroBlock Int
-zigZagOrderForward = VS.generate 64 inv
-  where inv i = fromMaybe 0 $ VS.findIndex (i ==) zigZagOrder
-
-zigZagReorderForward :: (Storable a)
-                     => MutableMacroBlock s a
-                     -> MutableMacroBlock s a
-                     -> ST s (MutableMacroBlock s a)
-{-# SPECIALIZE INLINE zigZagReorderForward :: MutableMacroBlock s Int32
-                                           -> MutableMacroBlock s Int32
-                                           -> ST s (MutableMacroBlock s Int32) #-}
-{-# SPECIALIZE INLINE zigZagReorderForward :: MutableMacroBlock s Int16
-                                           -> MutableMacroBlock s Int16
-                                           -> ST s (MutableMacroBlock s Int16) #-}
-{-# SPECIALIZE INLINE zigZagReorderForward :: MutableMacroBlock s Word8
-                                           -> MutableMacroBlock s Word8
-                                           -> ST s (MutableMacroBlock s Word8) #-}
-zigZagReorderForward zigzaged block = ordering zigZagOrderForward >> return zigzaged
-  where ordering !table = reorder (0 :: Int)
-          where reorder !i | i >= 64 = return ()
-                reorder i  = do
-                     let idx = table `VS.unsafeIndex` i
-                     v <- block `M.unsafeRead` idx
-                     (zigzaged `M.unsafeWrite` i) v
-                     reorder (i + 1)
-
-zigZagReorder :: MutableMacroBlock s Int16 -> MutableMacroBlock s Int16
-              -> ST s (MutableMacroBlock s Int16)
-zigZagReorder zigzaged block = do
-    let update i =  do
-            let idx = zigZagOrder `VS.unsafeIndex` i
-            v <- block `M.unsafeRead` idx
-            (zigzaged `M.unsafeWrite` i) v
-
-        reorder 63 = update 63
-        reorder i  = update i >> reorder (i + 1)
-
-    reorder (0 :: Int)
-    return zigzaged
-
--- | Unpack an int of the given size encoded from MSB to LSB.
-unpackInt :: Int -> BoolReader s Int32
-unpackInt = getNextIntJpg
-
-{-# INLINE rasterMap #-}
-rasterMap :: (Monad m)
-          => Int -> Int -> (Int -> Int -> m ())
-          -> m ()
-rasterMap width height f = liner 0
-  where liner y | y >= height = return ()
-        liner y = columner 0
-          where columner x | x >= width = liner (y + 1)
-                columner x = f x y >> columner (x + 1)
-
-pixelClamp :: Int16 -> Word8
-pixelClamp n = fromIntegral . min 255 $ max 0 n
-
--- | Given a size coefficient (how much a pixel span horizontally
--- and vertically), the position of the macroblock, return a list
--- of indices and value to be stored in an array (like the final
--- image)
-unpackMacroBlock :: Int    -- ^ Component count
-                 -> Int -- ^ Width coefficient
-                 -> Int -- ^ Height coefficient
-                 -> Int -- ^ Component index
-                 -> Int -- ^ x
-                 -> Int -- ^ y
-                 -> MutableImage s PixelYCbCr8
-                 -> MutableMacroBlock s Int16
-                 -> ST s ()
-unpackMacroBlock compCount wCoeff hCoeff compIdx x y
-                 (MutableImage { mutableImageWidth = imgWidth,
-                                 mutableImageHeight = imgHeight, mutableImageData = img })
-                 block = rasterMap dctBlockSize dctBlockSize unpacker
-  where unpacker i j = do
-          let yBase = y * dctBlockSize + j * hCoeff
-          compVal <- pixelClamp <$> (block `M.unsafeRead` (i + j * dctBlockSize))
-          rasterMap wCoeff hCoeff $ \wDup hDup -> do
-             let xBase = x * dctBlockSize + i * wCoeff
-                 xPos = xBase + wDup
-                 yPos = yBase + hDup
-
-             when (xPos < imgWidth && yPos < imgHeight)
-                  (do let mutableIdx = (xPos + yPos * imgWidth) * compCount + compIdx
-                      (img `M.unsafeWrite` mutableIdx) compVal)
-
--- | This is one of the most important function of the decoding,
--- it form the barebone decoding pipeline for macroblock. It's all
--- there is to know for macro block transformation
-decodeMacroBlock :: MacroBlock DctCoefficients
-                 -> MutableMacroBlock s Int16
-                 -> MutableMacroBlock s Int16
-                 -> ST s (MutableMacroBlock s Int16)
-decodeMacroBlock quantizationTable zigZagBlock block =
-    deQuantize quantizationTable block >>= zigZagReorder zigZagBlock
-                                       >>= inverseDirectCosineTransform
-
− src/Codec/Picture/Jpg/DefaultTable.hs
@@ -1,294 +0,0 @@-{-# LANGUAGE TupleSections #-}
-{-# LANGUAGE FlexibleContexts #-}
--- | Module used by the jpeg decoder internally, shouldn't be used
--- in user code.
-module Codec.Picture.Jpg.DefaultTable( DctComponent( .. )
-                                     , HuffmanTree( .. )
-                                     , HuffmanTable
-                                     , HuffmanPackedTree
-                                     , MacroBlock
-                                     , QuantificationTable
-                                     , HuffmanWriterCode 
-                                     , scaleQuantisationMatrix
-                                     , makeMacroBlock
-                                     , makeInverseTable
-                                     , buildHuffmanTree
-                                     , packHuffmanTree
-                                     , huffmanPackedDecode
-
-                                     , defaultChromaQuantizationTable
-
-                                     , defaultLumaQuantizationTable
-
-                                     , defaultAcChromaHuffmanTree
-                                     , defaultAcChromaHuffmanTable
-
-                                     , defaultAcLumaHuffmanTree 
-                                     , defaultAcLumaHuffmanTable 
-
-                                     , defaultDcChromaHuffmanTree 
-                                     , defaultDcChromaHuffmanTable
-
-                                     , defaultDcLumaHuffmanTree
-                                     , defaultDcLumaHuffmanTable
-                                     ) where
-
-import Data.Int( Int16 )
-import Foreign.Storable ( Storable )
-import Control.Monad.ST( runST )
-import qualified Data.Vector.Storable as SV
-import qualified Data.Vector as V
-import Data.Bits( unsafeShiftL, (.|.), (.&.) )
-import Data.Word( Word8, Word16 )
-import Data.List( foldl' )
-import qualified Data.Vector.Storable.Mutable as M
-
-import Codec.Picture.BitWriter
-
--- | Tree storing the code used for huffman encoding.
-data HuffmanTree = Branch HuffmanTree HuffmanTree -- ^ If bit is 0 take the first subtree, if 1, the right.
-                 | Leaf Word8       -- ^ We should output the value
-                 | Empty            -- ^ no value present
-                 deriving (Eq, Show)
-
-type HuffmanPackedTree = SV.Vector Word16
-
-type HuffmanWriterCode = V.Vector (Word8, Word16)
-
-packHuffmanTree :: HuffmanTree -> HuffmanPackedTree
-packHuffmanTree tree = runST $ do
-    table <- M.replicate 512 0x8000
-    let aux (Empty) idx = return $ idx + 1
-        aux (Leaf v) idx = do
-            (table `M.unsafeWrite` idx) $ fromIntegral v .|. 0x4000
-            return $ idx + 1
-
-        aux (Branch i1@(Leaf _) i2@(Leaf _)) idx =
-            aux i1 idx >>= aux i2
-
-        aux (Branch i1@(Leaf _) i2) idx = do
-            _ <- aux i1 idx
-            ix2 <- aux i2 $ idx + 2
-            (table `M.unsafeWrite` (idx + 1)) $ fromIntegral $ idx + 2
-            return ix2
-
-        aux (Branch i1 i2@(Leaf _)) idx = do
-            ix1 <- aux i1 (idx + 2)
-            _ <- aux i2 (idx + 1)
-            (table `M.unsafeWrite` idx) . fromIntegral $ idx + 2
-            return ix1
-
-        aux (Branch i1 i2) idx = do
-            ix1 <- aux i1 (idx + 2)
-            ix2 <- aux i2 ix1
-            (table `M.unsafeWrite` idx) (fromIntegral $ idx + 2)
-            (table `M.unsafeWrite` (idx + 1)) (fromIntegral ix1)
-            return ix2
-    _ <- aux tree 0
-    SV.unsafeFreeze table
-
-makeInverseTable :: HuffmanTree -> HuffmanWriterCode
-makeInverseTable t = V.replicate 255 (0,0) V.// inner 0 0 t
-  where inner _     _     Empty   = []
-        inner depth code (Leaf v) = [(fromIntegral v, (depth, code))]
-        inner depth code (Branch l r) =
-          inner (depth + 1) shifted l ++ inner (depth + 1) (shifted .|. 1) r
-            where shifted = code `unsafeShiftL` 1
-
--- | Represent a compact array of 8 * 8 values. The size
--- is not guarenteed by type system, but if makeMacroBlock is
--- used, everything should be fine size-wise
-type MacroBlock a = SV.Vector a
-
-type QuantificationTable = MacroBlock Int16
-
--- | Helper function to create pure macro block of the good size.
-makeMacroBlock :: (Storable a) => [a] -> MacroBlock a
-makeMacroBlock = SV.fromListN 64
-
--- | Enumeration used to search in the tables for different components.
-data DctComponent = DcComponent | AcComponent
-    deriving (Eq, Show)
-
--- | Transform parsed coefficients from the jpeg header to a
--- tree which can be used to decode data.
-buildHuffmanTree :: [[Word8]] -> HuffmanTree
-buildHuffmanTree table = foldl' insertHuffmanVal Empty
-                       . concatMap (\(i, t) -> map (i + 1,) t)
-                       $ zip ([0..] :: [Int]) table
-  where isTreeFullyDefined Empty = False
-        isTreeFullyDefined (Leaf _) = True
-        isTreeFullyDefined (Branch l r) = isTreeFullyDefined l && isTreeFullyDefined r
-
-        insertHuffmanVal Empty (0, val) = Leaf val
-        insertHuffmanVal Empty (d, val) = Branch (insertHuffmanVal Empty (d - 1, val)) Empty
-        insertHuffmanVal (Branch l r) (d, val)
-            | isTreeFullyDefined l = Branch l (insertHuffmanVal r (d - 1, val))
-            | otherwise            = Branch (insertHuffmanVal l (d - 1, val)) r
-        insertHuffmanVal (Leaf _) _ = error "Inserting in value, shouldn't happen"
-
-scaleQuantisationMatrix :: Int -> QuantificationTable -> QuantificationTable 
-scaleQuantisationMatrix quality
-    | quality < 0 = scaleQuantisationMatrix 0
-        -- shouldn't show much difference than with 1,
-        -- but hey, at least we're complete
-    | quality == 0 = SV.map (scale (10000 :: Int))
-    | quality < 50 = let qq = 5000 `div` quality
-                     in SV.map (scale qq)
-    | otherwise    = SV.map (scale q)
-          where q = 200 - quality * 2
-                scale coeff i = fromIntegral . min 255 
-                                             . max 1 
-                                             $ fromIntegral i * coeff `div` 100
-
-huffmanPackedDecode :: HuffmanPackedTree -> BoolReader s Word8
-huffmanPackedDecode table = getNextBitJpg >>= aux 0
-  where aux idx b
-            | (v .&. 0x8000) /= 0 = return  0
-            | (v .&. 0x4000) /= 0 = return . fromIntegral $ v .&. 0xFF
-            | otherwise = getNextBitJpg >>= aux v
-          where tableIndex | b = idx + 1
-                           | otherwise = idx
-                v = table `SV.unsafeIndex` fromIntegral tableIndex
-
-defaultLumaQuantizationTable :: QuantificationTable
-defaultLumaQuantizationTable = makeMacroBlock
-    [16, 11, 10, 16,  24,  40,  51,  61
-    ,12, 12, 14, 19,  26,  58,  60,  55
-    ,14, 13, 16, 24,  40,  57,  69,  56
-    ,14, 17, 22, 29,  51,  87,  80,  62
-    ,18, 22, 37, 56,  68, 109, 103,  77
-    ,24, 35, 55, 64,  81, 104, 113,  92
-    ,49, 64, 78, 87, 103, 121, 120, 101
-    ,72, 92, 95, 98, 112, 100, 103,  99
-    ]
-
-defaultChromaQuantizationTable :: QuantificationTable
-defaultChromaQuantizationTable = makeMacroBlock
-    [17, 18, 24, 47, 99, 99, 99, 99
-    ,18, 21, 26, 66, 99, 99, 99, 99
-    ,24, 26, 56, 99, 99, 99, 99, 99
-    ,47, 66, 99, 99, 99, 99, 99, 99
-    ,99, 99, 99, 99, 99, 99, 99, 99
-    ,99, 99, 99, 99, 99, 99, 99, 99
-    ,99, 99, 99, 99, 99, 99, 99, 99
-    ,99, 99, 99, 99, 99, 99, 99, 99
-    ]
-
-defaultDcLumaHuffmanTree :: HuffmanTree
-defaultDcLumaHuffmanTree = buildHuffmanTree defaultDcLumaHuffmanTable
-
--- | From the Table K.3 of ITU-81 (p153)
-defaultDcLumaHuffmanTable :: HuffmanTable
-defaultDcLumaHuffmanTable =
-    [ []
-    , [0]
-    , [1, 2, 3, 4, 5]
-    , [6]
-    , [7]
-    , [8]
-    , [9]
-    , [10]
-    , [11]
-    , []
-    , []
-    , []
-    , []
-    , []
-    , []
-    , []
-    ]
-
-defaultDcChromaHuffmanTree :: HuffmanTree
-defaultDcChromaHuffmanTree = buildHuffmanTree defaultDcChromaHuffmanTable
-
--- | From the Table K.4 of ITU-81 (p153)
-defaultDcChromaHuffmanTable :: HuffmanTable
-defaultDcChromaHuffmanTable = 
-    [ []
-    , [0, 1, 2]
-    , [3]
-    , [4]
-    , [5]
-    , [6]
-    , [7]
-    , [8]
-    , [9]
-    , [10]
-    , [11]
-    , []
-    , []
-    , []
-    , []
-    , []
-    ]
-
-defaultAcLumaHuffmanTree :: HuffmanTree
-defaultAcLumaHuffmanTree = buildHuffmanTree defaultAcLumaHuffmanTable
-
--- | From the Table K.5 of ITU-81 (p154)
-defaultAcLumaHuffmanTable :: HuffmanTable
-defaultAcLumaHuffmanTable =
-    [ []
-    , [0x01, 0x02]
-    , [0x03]
-    , [0x00, 0x04, 0x11]
-    , [0x05, 0x12, 0x21]
-    , [0x31, 0x41]
-    , [0x06, 0x13, 0x51, 0x61]
-    , [0x07, 0x22, 0x71]
-    , [0x14, 0x32, 0x81, 0x91, 0xA1]
-    , [0x08, 0x23, 0x42, 0xB1, 0xC1]
-    , [0x15, 0x52, 0xD1, 0xF0]
-    , [0x24, 0x33, 0x62, 0x72]
-    , []
-    , []
-    , [0x82]
-    , [0x09, 0x0A, 0x16, 0x17, 0x18, 0x19, 0x1A, 0x25, 0x26, 0x27, 0x28, 0x29, 0x2A, 0x34, 0x35
-      ,0x36, 0x37, 0x38, 0x39, 0x3A, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49, 0x4A, 0x53, 0x54
-      ,0x55, 0x56, 0x57, 0x58, 0x59, 0x5A, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69, 0x6A, 0x73
-      ,0x74, 0x75, 0x76, 0x77, 0x78, 0x79, 0x7A, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89, 0x8A
-      ,0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98, 0x99, 0x9A, 0xA2, 0xA3, 0xA4, 0xA5, 0xA6, 0xA7
-      ,0xA8, 0xA9, 0xAA, 0xB2, 0xB3, 0xB4, 0xB5, 0xB6, 0xB7, 0xB8, 0xB9, 0xBA, 0xC2, 0xC3, 0xC4
-      ,0xC5, 0xC6, 0xC7, 0xC8, 0xC9, 0xCA, 0xD2, 0xD3, 0xD4, 0xD5, 0xD6, 0xD7, 0xD8, 0xD9, 0xDA
-      ,0xE1, 0xE2, 0xE3, 0xE4, 0xE5, 0xE6, 0xE7, 0xE8, 0xE9, 0xEA, 0xF1, 0xF2, 0xF3, 0xF4, 0xF5
-      ,0xF6, 0xF7, 0xF8, 0xF9, 0xFA]
-    ]
-
-type HuffmanTable = [[Word8]]
-
-defaultAcChromaHuffmanTree :: HuffmanTree
-defaultAcChromaHuffmanTree = buildHuffmanTree defaultAcChromaHuffmanTable 
-
-defaultAcChromaHuffmanTable :: HuffmanTable
-defaultAcChromaHuffmanTable = 
-    [ []
-    , [0x00, 0x01]
-    , [0x02]
-    , [0x03, 0x11]
-    , [0x04, 0x05, 0x21, 0x31]
-    , [0x06, 0x12, 0x41, 0x51]
-    , [0x07, 0x61, 0x71]
-    , [0x13, 0x22, 0x32, 0x81]
-    , [0x08, 0x14, 0x42, 0x91, 0xA1, 0xB1, 0xC1]
-    , [0x09, 0x23, 0x33, 0x52, 0xF0]
-    , [0x15, 0x62, 0x72, 0xD1]
-    , [0x0A, 0x16, 0x24, 0x34]
-    , []
-    , [0xE1]
-    , [0x25, 0xF1]
-    , [ 0x17, 0x18, 0x19, 0x1A, 0x26, 0x27, 0x28, 0x29, 0x2A, 0x35
-      , 0x36, 0x37, 0x38, 0x39, 0x3A, 0x43, 0x44, 0x45, 0x46, 0x47
-      , 0x48, 0x49, 0x4A, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59
-      , 0x5A, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69, 0x6A, 0x73
-      , 0x74, 0x75, 0x76, 0x77, 0x78, 0x79, 0x7A, 0x82, 0x83, 0x84
-      , 0x85, 0x86, 0x87, 0x88, 0x89, 0x8A, 0x92, 0x93, 0x94, 0x95
-      , 0x96, 0x97, 0x98, 0x99, 0x9A, 0xA2, 0xA3, 0xA4, 0xA5, 0xA6
-      , 0xA7, 0xA8, 0xA9, 0xAA, 0xB2, 0xB3, 0xB4, 0xB5, 0xB6, 0xB7
-      , 0xB8, 0xB9, 0xBA, 0xC2, 0xC3, 0xC4, 0xC5, 0xC6, 0xC7, 0xC8
-      , 0xC9, 0xCA, 0xD2, 0xD3, 0xD4, 0xD5, 0xD6, 0xD7, 0xD8, 0xD9
-      , 0xDA, 0xE2, 0xE3, 0xE4, 0xE5, 0xE6, 0xE7, 0xE8, 0xE9, 0xEA
-      , 0xF2, 0xF3, 0xF4, 0xF5, 0xF6, 0xF7, 0xF8, 0xF9, 0xFA
-      ]
-    ]
-
− src/Codec/Picture/Jpg/FastDct.hs
@@ -1,218 +0,0 @@-{-# LANGUAGE CPP #-}-{-# LANGUAGE TypeFamilies #-}-module Codec.Picture.Jpg.FastDct( referenceDct, fastDctLibJpeg ) where--#if !MIN_VERSION_base(4,8,0)-import Control.Applicative( (<$>) )-#endif--import Data.Int( Int16, Int32 )-import Data.Bits( unsafeShiftR, unsafeShiftL )-import Control.Monad.ST( ST )--import qualified Data.Vector.Storable.Mutable as M--import Codec.Picture.Jpg.Types-import Control.Monad( forM, forM_ )---- | Reference implementation of the DCT, directly implementing the formula--- of ITU-81. It's slow as hell, perform to many operations, but is accurate--- and a good reference point.-referenceDct :: MutableMacroBlock s Int32-             -> MutableMacroBlock s Int16-             -> ST s (MutableMacroBlock s Int32)-referenceDct workData block = do-  forM_ [(u, v) | u <- [0 :: Int .. dctBlockSize - 1], v <- [0..dctBlockSize - 1]] $ \(u,v) -> do-    val <- at (u,v)-    (workData `M.unsafeWrite` (v * dctBlockSize + u)) . truncate $ (1 / 4) * c u * c v * val--  return workData- where -- at :: (Int, Int) -> ST s Float-   at (u,v) = do-     toSum <--        forM [(x,y) | x <- [0..dctBlockSize - 1], y <- [0..dctBlockSize - 1 :: Int]] $ \(x,y) -> do-            sample <- fromIntegral <$> (block `M.unsafeRead` (y * dctBlockSize + x))-            return $ sample * cos ((2 * fromIntegral x + 1) * fromIntegral u * (pi :: Float)/ 16) -                            * cos ((2 * fromIntegral y + 1) * fromIntegral v * pi / 16)-     return $ sum toSum--   c 0 = 1 / sqrt 2-   c _ = 1--pASS1_BITS, cONST_BITS :: Int-cONST_BITS = 13-pASS1_BITS =  2---fIX_0_298631336, fIX_0_390180644, fIX_0_541196100,-    fIX_0_765366865, fIX_0_899976223, fIX_1_175875602,-    fIX_1_501321110, fIX_1_847759065, fIX_1_961570560,-    fIX_2_053119869, fIX_2_562915447, fIX_3_072711026 :: Int32-fIX_0_298631336 = 2446    -- FIX(0.298631336) */-fIX_0_390180644 = 3196    -- FIX(0.390180644) */-fIX_0_541196100 = 4433    -- FIX(0.541196100) */-fIX_0_765366865 = 6270    -- FIX(0.765366865) */-fIX_0_899976223 = 7373    -- FIX(0.899976223) */-fIX_1_175875602 = 9633    -- FIX(1.175875602) */-fIX_1_501321110 = 12299    -- FIX(1.501321110) */-fIX_1_847759065 = 15137    -- FIX(1.847759065) */-fIX_1_961570560 = 16069    -- FIX(1.961570560) */-fIX_2_053119869 = 16819    -- FIX(2.053119869) */-fIX_2_562915447 = 20995    -- FIX(2.562915447) */-fIX_3_072711026 = 25172    -- FIX(3.072711026) */--cENTERJSAMPLE :: Int32-cENTERJSAMPLE = 128---- | Fast DCT extracted from libjpeg-fastDctLibJpeg :: MutableMacroBlock s Int32-        -> MutableMacroBlock s Int16-        -> ST s (MutableMacroBlock s Int32)-fastDctLibJpeg workData sample_block = do- firstPass workData  0- secondPass workData 7- {-_ <- mutate (\_ a -> a `quot` 8) workData-}- return workData-  where -- Pass 1: process rows.-        -- Note results are scaled up by sqrt(8) compared to a true DCT;-        -- furthermore, we scale the results by 2**PASS1_BITS.-        firstPass         _ i | i == dctBlockSize = return ()-        firstPass dataBlock i = do-            let baseIdx = i * dctBlockSize-                readAt idx = fromIntegral <$> sample_block `M.unsafeRead` (baseIdx + idx)-                mult = (*)-                writeAt idx = dataBlock `M.unsafeWrite` (baseIdx + idx)-                writeAtPos idx n = (dataBlock `M.unsafeWrite` (baseIdx + idx))-                                    (n `unsafeShiftR` (cONST_BITS - pASS1_BITS))--            blk0 <- readAt 0-            blk1 <- readAt 1-            blk2 <- readAt 2-            blk3 <- readAt 3-            blk4 <- readAt 4-            blk5 <- readAt 5-            blk6 <- readAt 6-            blk7 <- readAt 7--            let tmp0 = blk0 + blk7-                tmp1 = blk1 + blk6-                tmp2 = blk2 + blk5-                tmp3 = blk3 + blk4--                tmp10 = tmp0 + tmp3-                tmp12 = tmp0 - tmp3-                tmp11 = tmp1 + tmp2-                tmp13 = tmp1 - tmp2--                tmp0' = blk0 - blk7-                tmp1' = blk1 - blk6-                tmp2' = blk2 - blk5-                tmp3' = blk3 - blk4--            -- Stage 4 and output-            writeAt 0 $ (tmp10 + tmp11 - dctBlockSize * cENTERJSAMPLE) `unsafeShiftL` pASS1_BITS-            writeAt 4 $ (tmp10 - tmp11) `unsafeShiftL` pASS1_BITS--            let z1 = mult (tmp12 + tmp13) fIX_0_541196100-                     + (1 `unsafeShiftL` (cONST_BITS - pASS1_BITS - 1))--            writeAtPos 2 $ z1 + mult tmp12 fIX_0_765366865-            writeAtPos 6 $ z1 - mult tmp13 fIX_1_847759065--            let tmp10' = tmp0' + tmp3'-                tmp11' = tmp1' + tmp2'-                tmp12' = tmp0' + tmp2'-                tmp13' = tmp1' + tmp3'-                z1' = mult (tmp12' + tmp13') fIX_1_175875602 --  c3 */-                        -- Add fudge factor here for final descale. */-                        + (1 `unsafeShiftL` (cONST_BITS - pASS1_BITS-1))-                tmp0'' = mult tmp0' fIX_1_501321110-                tmp1'' = mult tmp1' fIX_3_072711026-                tmp2'' = mult tmp2' fIX_2_053119869-                tmp3'' = mult tmp3' fIX_0_298631336--                tmp10'' = mult tmp10' (- fIX_0_899976223)-                tmp11'' = mult tmp11' (- fIX_2_562915447)-                tmp12'' = mult tmp12' (- fIX_0_390180644) + z1'-                tmp13'' = mult tmp13' (- fIX_1_961570560) + z1'--            writeAtPos 1 $ tmp0'' + tmp10'' + tmp12''-            writeAtPos 3 $ tmp1'' + tmp11'' + tmp13''-            writeAtPos 5 $ tmp2'' + tmp11'' + tmp12''-            writeAtPos 7 $ tmp3'' + tmp10'' + tmp13''--            firstPass dataBlock $ i + 1--        -- Pass 2: process columns.-        -- We remove the PASS1_BITS scaling, but leave the results scaled up-        -- by an overall factor of 8.-        secondPass :: M.STVector s Int32 -> Int -> ST s ()-        secondPass _     (-1) = return ()-        secondPass block i = do-            let readAt idx = block `M.unsafeRead` ((7 - i) + idx * dctBlockSize)-                mult = (*)-                writeAt idx = block `M.unsafeWrite` (dctBlockSize * idx + (7 - i))-                writeAtPos idx n = (block `M.unsafeWrite` (dctBlockSize * idx + (7 - i))) $ n `unsafeShiftR` (cONST_BITS + pASS1_BITS + 3)-            blk0 <- readAt 0-            blk1 <- readAt 1-            blk2 <- readAt 2-            blk3 <- readAt 3-            blk4 <- readAt 4-            blk5 <- readAt 5-            blk6 <- readAt 6-            blk7 <- readAt 7--            let tmp0 = blk0 + blk7-                tmp1 = blk1 + blk6-                tmp2 = blk2 + blk5-                tmp3 = blk3 + blk4--                -- Add fudge factor here for final descale. */-                tmp10 = tmp0 + tmp3 + (1 `unsafeShiftL` (pASS1_BITS-1))-                tmp12 = tmp0 - tmp3-                tmp11 = tmp1 + tmp2-                tmp13 = tmp1 - tmp2--                tmp0' = blk0 - blk7-                tmp1' = blk1 - blk6-                tmp2' = blk2 - blk5-                tmp3' = blk3 - blk4--            writeAt 0 $ (tmp10 + tmp11) `unsafeShiftR` (pASS1_BITS + 3)-            writeAt 4 $ (tmp10 - tmp11) `unsafeShiftR` (pASS1_BITS + 3)--            let z1 = mult (tmp12 + tmp13) fIX_0_541196100-                    + (1 `unsafeShiftL` (cONST_BITS + pASS1_BITS - 1))--            writeAtPos 2 $ z1 + mult tmp12 fIX_0_765366865-            writeAtPos 6 $ z1 - mult tmp13 fIX_1_847759065--            let tmp10' = tmp0' + tmp3'-                tmp11' = tmp1' + tmp2'-                tmp12' = tmp0' + tmp2'-                tmp13' = tmp1' + tmp3'--                z1' = mult (tmp12' + tmp13') fIX_1_175875602-                    -- Add fudge factor here for final descale. */-                   + 1 `unsafeShiftL` (cONST_BITS+pASS1_BITS-1);--                tmp0''  = mult tmp0'    fIX_1_501321110-                tmp1''  = mult tmp1'    fIX_3_072711026-                tmp2''  = mult tmp2'    fIX_2_053119869-                tmp3''  = mult tmp3'    fIX_0_298631336-                tmp10'' = mult tmp10' (- fIX_0_899976223)-                tmp11'' = mult tmp11' (- fIX_2_562915447)-                tmp12'' = mult tmp12' (- fIX_0_390180644)-                            + z1'-                tmp13'' = mult tmp13' (- fIX_1_961570560)-                            + z1'-            writeAtPos 1 $ tmp0'' + tmp10'' + tmp12''-            writeAtPos 3 $ tmp1'' + tmp11'' + tmp13''-            writeAtPos 5 $ tmp2'' + tmp11'' + tmp12''-            writeAtPos 7 $ tmp3'' + tmp10'' + tmp13''--            secondPass block (i - 1)--{-# ANN module "HLint: ignore Use camelCase" #-}-{-# ANN module "HLint: ignore Reduce duplication" #-}-
− src/Codec/Picture/Jpg/FastIdct.hs
@@ -1,229 +0,0 @@-{-# LANGUAGE FlexibleContexts #-}
-{-# LANGUAGE TypeFamilies #-}
--- | Module providing a 'fast' implementation of IDCT
---
--- inverse two dimensional DCT, Chen-Wang algorithm       
--- (cf. IEEE ASSP-32, pp. 803-816, Aug. 1984)             
--- 32-bit integer arithmetic (8 bit coefficients)         
--- 11 mults, 29 adds per DCT                              
---                                      sE, 18.8.91       
---
--- coefficients extended to 12 bit for IEEE1180-1990      
--- compliance                           sE,  2.1.94       
---
--- this code assumes >> to be a two's-complement arithmetic
--- right shift: (-2)>>1 == -1 , (-3)>>1 == -2               
-module Codec.Picture.Jpg.FastIdct( MutableMacroBlock
-                                 , fastIdct
-                                 , mutableLevelShift
-                                 , createEmptyMutableMacroBlock
-                                 ) where
-
-import qualified Data.Vector.Storable as V
-import Control.Monad.ST( ST )
-import Data.Bits( unsafeShiftL, unsafeShiftR )
-import Data.Int( Int16 )
-import qualified Data.Vector.Storable.Mutable as M
-
-import Codec.Picture.Jpg.Types
-
-iclip :: V.Vector Int16
-iclip = V.fromListN 1024 [ val i| i <- [(-512) .. 511] ]
-    where val i | i < (-256) = -256
-                | i > 255    =  255
-                | otherwise  =  i
-
-data IDctStage = IDctStage { 
-        x0 :: {-# UNPACK #-} !Int,
-        x1 :: {-# UNPACK #-} !Int,
-        x2 :: {-# UNPACK #-} !Int,
-        x3 :: {-# UNPACK #-} !Int,
-        x4 :: {-# UNPACK #-} !Int,
-        x5 :: {-# UNPACK #-} !Int,
-        x6 :: {-# UNPACK #-} !Int,
-        x7 :: {-# UNPACK #-} !Int,
-        x8 :: {-# UNPACK #-} !Int
-    }
-
-w1, w2, w3, w5, w6, w7 :: Int
-w1 = 2841 -- 2048*sqrt(2)*cos(1*pi/16)
-w2 = 2676 -- 2048*sqrt(2)*cos(2*pi/16)
-w3 = 2408 -- 2048*sqrt(2)*cos(3*pi/16)
-w5 = 1609 -- 2048*sqrt(2)*cos(5*pi/16)
-w6 = 1108 -- 2048*sqrt(2)*cos(6*pi/16)
-w7 = 565  -- 2048*sqrt(2)*cos(7*pi/16)
-
--- row (horizontal) IDCT
---
---           7                       pi         1
--- dst[k] = sum c[l] * src[l] * cos( -- * ( k + - ) * l )
---          l=0                      8          2
---
--- where: c[0]    = 128
---        c[1..7] = 128*sqrt(2)
-idctRow :: MutableMacroBlock s Int16 -> Int ->  ST s ()
-idctRow blk idx = do
-  xx0 <- blk `M.unsafeRead` (0 + idx)
-  xx1 <- blk `M.unsafeRead` (4 + idx) 
-  xx2 <- blk `M.unsafeRead` (6 + idx)
-  xx3 <- blk `M.unsafeRead` (2 + idx)
-  xx4 <- blk `M.unsafeRead` (1 + idx)
-  xx5 <- blk `M.unsafeRead` (7 + idx)
-  xx6 <- blk `M.unsafeRead` (5 + idx)
-  xx7 <- blk `M.unsafeRead` (3 + idx)
-  let initialState = IDctStage { x0 = (fromIntegral xx0 `unsafeShiftL` 11) + 128
-                               , x1 =  fromIntegral xx1 `unsafeShiftL` 11
-                               , x2 =  fromIntegral xx2
-                               , x3 =  fromIntegral xx3
-                               , x4 =  fromIntegral xx4
-                               , x5 =  fromIntegral xx5
-                               , x6 =  fromIntegral xx6
-                               , x7 =  fromIntegral xx7
-                               , x8 = 0
-                               } 
-
-      firstStage c = c { x4 = x8'  + (w1 - w7) * x4 c
-                       , x5 = x8'  - (w1 + w7) * x5 c
-                       , x6 = x8'' - (w3 - w5) * x6 c
-                       , x7 = x8'' - (w3 + w5) * x7 c
-                       , x8 = x8''
-                       }
-          where x8' = w7 * (x4 c + x5 c)
-                x8'' = w3 * (x6 c + x7 c)
-
-      secondStage c = c { x0 = x0 c - x1 c
-                        , x8 = x0 c + x1 c 
-                        , x1 = x1''
-                        , x2 = x1' - (w2 + w6) * x2 c
-                        , x3 = x1' + (w2 - w6) * x3 c
-                        , x4 = x4 c - x6 c
-                        , x6 = x5 c + x7 c
-                        , x5 = x5 c - x7 c
-                        }
-            where x1'  = w6 * (x3 c + x2 c)
-                  x1'' = x4 c + x6 c
-
-      thirdStage c = c { x7 = x8 c + x3 c
-                       , x8 = x8 c - x3 c
-                       , x3 = x0 c + x2 c
-                       , x0 = x0 c - x2 c
-                       , x2 = (181 * (x4 c + x5 c) + 128) `unsafeShiftR` 8
-                       , x4 = (181 * (x4 c - x5 c) + 128) `unsafeShiftR` 8
-                       }
-      scaled c = c { x0 = (x7 c + x1 c) `unsafeShiftR` 8
-                   , x1 = (x3 c + x2 c) `unsafeShiftR` 8
-                   , x2 = (x0 c + x4 c) `unsafeShiftR` 8
-                   , x3 = (x8 c + x6 c) `unsafeShiftR` 8
-                   , x4 = (x8 c - x6 c) `unsafeShiftR` 8
-                   , x5 = (x0 c - x4 c) `unsafeShiftR` 8
-                   , x6 = (x3 c - x2 c) `unsafeShiftR` 8
-                   , x7 = (x7 c - x1 c) `unsafeShiftR` 8
-                   }
-      transformed = scaled . thirdStage . secondStage $ firstStage initialState
-
-  (blk `M.unsafeWrite` (0 + idx)) . fromIntegral $ x0 transformed
-  (blk `M.unsafeWrite` (1 + idx)) . fromIntegral $ x1 transformed
-  (blk `M.unsafeWrite` (2 + idx)) . fromIntegral $ x2 transformed
-  (blk `M.unsafeWrite` (3 + idx)) . fromIntegral $ x3 transformed
-  (blk `M.unsafeWrite` (4 + idx)) . fromIntegral $ x4 transformed
-  (blk `M.unsafeWrite` (5 + idx)) . fromIntegral $ x5 transformed
-  (blk `M.unsafeWrite` (6 + idx)) . fromIntegral $ x6 transformed
-  (blk `M.unsafeWrite` (7 + idx)) . fromIntegral $ x7 transformed
-
--- column (vertical) IDCT
---
---             7                         pi         1
--- dst[8*k] = sum c[l] * src[8*l] * cos( -- * ( k + - ) * l )
---            l=0                        8          2
---
--- where: c[0]    = 1/1024
---        c[1..7] = (1/1024)*sqrt(2)
---
-idctCol :: MutableMacroBlock s Int16 -> Int -> ST s ()
-idctCol blk idx = do
-  xx0 <- blk `M.unsafeRead` (    0 + idx)
-  xx1 <- blk `M.unsafeRead` (8 * 4 + idx)
-  xx2 <- blk `M.unsafeRead` (8 * 6 + idx)
-  xx3 <- blk `M.unsafeRead` (8 * 2 + idx)
-  xx4 <- blk `M.unsafeRead` (8     + idx)
-  xx5 <- blk `M.unsafeRead` (8 * 7 + idx)
-  xx6 <- blk `M.unsafeRead` (8 * 5 + idx)
-  xx7 <- blk `M.unsafeRead` (8 * 3 + idx)
-  let initialState = IDctStage { x0 = (fromIntegral xx0 `unsafeShiftL` 8) + 8192
-                               , x1 =  fromIntegral xx1 `unsafeShiftL` 8
-                               , x2 =  fromIntegral xx2
-                               , x3 =  fromIntegral xx3
-                               , x4 =  fromIntegral xx4
-                               , x5 =  fromIntegral xx5
-                               , x6 =  fromIntegral xx6
-                               , x7 =  fromIntegral xx7
-                               , x8 = 0
-                               } 
-      firstStage c = c { x4 = (x8'  + (w1 - w7) * x4 c) `unsafeShiftR` 3
-                       , x5 = (x8'  - (w1 + w7) * x5 c) `unsafeShiftR` 3
-                       , x6 = (x8'' - (w3 - w5) * x6 c) `unsafeShiftR` 3
-                       , x7 = (x8'' - (w3 + w5) * x7 c) `unsafeShiftR` 3
-                       , x8 = x8''
-                       }
-          where x8'  = w7 * (x4 c + x5 c) + 4
-                x8'' = w3 * (x6 c + x7 c) + 4
-
-      secondStage c = c { x8 = x0 c + x1 c
-                        , x0 = x0 c - x1 c
-                        , x2 = (x1' - (w2 + w6) * x2 c) `unsafeShiftR` 3
-                        , x3 = (x1' + (w2 - w6) * x3 c) `unsafeShiftR` 3
-                        , x4 = x4 c - x6 c
-                        , x1 = x1''
-                        , x6 = x5 c + x7 c
-                        , x5 = x5 c - x7 c
-                        }
-          where x1'  = w6 * (x3 c + x2 c) + 4
-                x1'' = x4 c + x6 c
-  
-      thirdStage c = c { x7 = x8 c + x3 c
-                       , x8 = x8 c - x3 c
-                       , x3 = x0 c + x2 c
-                       , x0 = x0 c - x2 c
-                       , x2 = (181 * (x4 c + x5 c) + 128) `unsafeShiftR` 8
-                       , x4 = (181 * (x4 c - x5 c) + 128) `unsafeShiftR` 8
-                       }
-
-      clip i | i < 511 = if i > -512 then iclip `V.unsafeIndex` (i + 512)
-                                    else iclip `V.unsafeIndex` 0
-            
-             | otherwise = iclip `V.unsafeIndex` 1023
-
-      f = thirdStage . secondStage $ firstStage initialState
-  (blk `M.unsafeWrite` (idx + 8*0)) . clip $ (x7 f + x1 f) `unsafeShiftR` 14
-  (blk `M.unsafeWrite` (idx + 8  )) . clip $ (x3 f + x2 f) `unsafeShiftR` 14
-  (blk `M.unsafeWrite` (idx + 8*2)) . clip $ (x0 f + x4 f) `unsafeShiftR` 14
-  (blk `M.unsafeWrite` (idx + 8*3)) . clip $ (x8 f + x6 f) `unsafeShiftR` 14
-  (blk `M.unsafeWrite` (idx + 8*4)) . clip $ (x8 f - x6 f) `unsafeShiftR` 14
-  (blk `M.unsafeWrite` (idx + 8*5)) . clip $ (x0 f - x4 f) `unsafeShiftR` 14
-  (blk `M.unsafeWrite` (idx + 8*6)) . clip $ (x3 f - x2 f) `unsafeShiftR` 14
-  (blk `M.unsafeWrite` (idx + 8*7)) . clip $ (x7 f - x1 f) `unsafeShiftR` 14
-
-
-{-# INLINE fastIdct #-}
--- | Algorithm to call to perform an IDCT, return the same
--- block that the one given as input.
-fastIdct :: MutableMacroBlock s Int16
-         -> ST s (MutableMacroBlock s Int16)
-fastIdct block = rows 0
-  where rows 8 = cols 0
-        rows i = idctRow block (8 * i) >> rows (i + 1)
-
-        cols 8 = return block
-        cols i = idctCol block i >> cols (i + 1)
-
-{-# INLINE mutableLevelShift #-}
--- | Perform a Jpeg level shift in a mutable fashion.
-mutableLevelShift :: MutableMacroBlock s Int16
-                  -> ST s (MutableMacroBlock s Int16)
-mutableLevelShift block = update 0
-  where update 64 = return block
-        update idx = do
-            val <- block `M.unsafeRead` idx
-            (block `M.unsafeWrite` idx) $ val + 128
-            update $ idx + 1
-
+ src/Codec/Picture/Jpg/Internal/Common.hs view
@@ -0,0 +1,240 @@+{-# LANGUAGE BangPatterns #-}
+{-# LANGUAGE TypeFamilies #-}
+{-# LANGUAGE CPP #-}
+module Codec.Picture.Jpg.Internal.Common
+    ( DctCoefficients
+    , JpgUnpackerParameter( .. )
+    , decodeInt
+    , dcCoefficientDecode
+    , deQuantize
+    , decodeRrrrSsss
+    , zigZagReorderForward 
+    , zigZagReorderForwardv
+    , zigZagReorder
+    , inverseDirectCosineTransform
+    , unpackInt
+    , unpackMacroBlock
+    , rasterMap
+    , decodeMacroBlock
+    , decodeRestartInterval
+    , toBlockSize
+    ) where
+
+#if !MIN_VERSION_base(4,8,0)
+import Control.Applicative( pure, (<$>) )
+#endif
+
+import Control.Monad( when )
+import Control.Monad.ST( ST, runST )
+import Data.Bits( unsafeShiftL, unsafeShiftR, (.&.) )
+import Data.Int( Int16, Int32 )
+import Data.Maybe( fromMaybe )
+import Data.Word( Word8 )
+import qualified Data.Vector.Storable as VS
+import qualified Data.Vector.Storable.Mutable as M
+import Foreign.Storable ( Storable )
+
+import Codec.Picture.Types
+import Codec.Picture.BitWriter
+import Codec.Picture.Jpg.Internal.Types
+import Codec.Picture.Jpg.Internal.FastIdct
+import Codec.Picture.Jpg.Internal.DefaultTable
+
+-- | Same as for DcCoefficient, to provide nicer type signatures
+type DctCoefficients = DcCoefficient
+
+data JpgUnpackerParameter = JpgUnpackerParameter
+    { dcHuffmanTree        :: !HuffmanPackedTree
+    , acHuffmanTree        :: !HuffmanPackedTree
+    , componentIndex       :: {-# UNPACK #-} !Int
+    , restartInterval      :: {-# UNPACK #-} !Int
+    , componentWidth       :: {-# UNPACK #-} !Int
+    , componentHeight      :: {-# UNPACK #-} !Int
+    , subSampling          :: !(Int, Int)
+    , coefficientRange     :: !(Int, Int)
+    , successiveApprox     :: !(Int, Int)
+    , readerIndex          :: {-# UNPACK #-} !Int
+      -- | When in progressive mode, we can have many
+      -- color in a scan or only one. The indices changes
+      -- on this fact, when mixed, there is whole 
+      -- MCU for all color components, spanning multiple
+      -- block lines. With only one color component we use
+      -- the normal raster order.
+    , indiceVector         :: {-# UNPACK #-} !Int
+    , blockIndex           :: {-# UNPACK #-} !Int
+    , blockMcuX            :: {-# UNPACK #-} !Int
+    , blockMcuY            :: {-# UNPACK #-} !Int
+    }
+    deriving Show
+
+toBlockSize :: Int -> Int
+toBlockSize v = (v + 7) `div` 8
+
+decodeRestartInterval :: BoolReader s Int32
+decodeRestartInterval = return (-1) {-  do
+  bits <- replicateM 8 getNextBitJpg
+  if bits == replicate 8 True
+     then do
+         marker <- replicateM 8 getNextBitJpg
+         return $ packInt marker
+     else return (-1)
+        -}
+
+{-# INLINE decodeInt #-}
+decodeInt :: Int -> BoolReader s Int32
+decodeInt ssss = do
+    signBit <- getNextBitJpg
+    let dataRange = 1 `unsafeShiftL` fromIntegral (ssss - 1)
+        leftBitCount = ssss - 1
+    -- First following bits store the sign of the coefficient, and counted in
+    -- SSSS, so the bit count for the int, is ssss - 1
+    if signBit
+       then (\w -> dataRange + fromIntegral w) <$> unpackInt leftBitCount
+       else (\w -> 1 - dataRange * 2 + fromIntegral w) <$> unpackInt leftBitCount
+
+decodeRrrrSsss :: HuffmanPackedTree -> BoolReader s (Int, Int)
+decodeRrrrSsss tree = do
+    rrrrssss <- huffmanPackedDecode tree
+    let rrrr = (rrrrssss `unsafeShiftR` 4) .&. 0xF
+        ssss =  rrrrssss .&. 0xF
+    pure (fromIntegral rrrr, fromIntegral ssss)
+
+dcCoefficientDecode :: HuffmanPackedTree -> BoolReader s DcCoefficient
+dcCoefficientDecode dcTree = do
+    ssss <- huffmanPackedDecode dcTree
+    if ssss == 0
+       then return 0
+       else fromIntegral <$> decodeInt (fromIntegral ssss)
+
+-- | Apply a quantization matrix to a macroblock
+{-# INLINE deQuantize #-}
+deQuantize :: MacroBlock Int16 -> MutableMacroBlock s Int16
+           -> ST s (MutableMacroBlock s Int16)
+deQuantize table block = update 0
+    where update 64 = return block
+          update i = do
+              val <- block `M.unsafeRead` i
+              let finalValue = val * (table `VS.unsafeIndex` i)
+              (block `M.unsafeWrite` i) finalValue
+              update $ i + 1
+
+inverseDirectCosineTransform :: MutableMacroBlock s Int16
+                             -> ST s (MutableMacroBlock s Int16)
+inverseDirectCosineTransform mBlock =
+    fastIdct mBlock >>= mutableLevelShift
+
+zigZagOrder :: MacroBlock Int
+zigZagOrder = makeMacroBlock $ concat
+    [[ 0, 1, 5, 6,14,15,27,28]
+    ,[ 2, 4, 7,13,16,26,29,42]
+    ,[ 3, 8,12,17,25,30,41,43]
+    ,[ 9,11,18,24,31,40,44,53]
+    ,[10,19,23,32,39,45,52,54]
+    ,[20,22,33,38,46,51,55,60]
+    ,[21,34,37,47,50,56,59,61]
+    ,[35,36,48,49,57,58,62,63]
+    ]
+
+zigZagReorderForwardv :: (Storable a, Num a) => VS.Vector a -> VS.Vector a
+zigZagReorderForwardv vec = runST $ do
+    v <- M.new 64
+    mv <- VS.thaw vec
+    zigZagReorderForward v mv >>= VS.freeze
+
+zigZagOrderForward :: MacroBlock Int
+zigZagOrderForward = VS.generate 64 inv
+  where inv i = fromMaybe 0 $ VS.findIndex (i ==) zigZagOrder
+
+zigZagReorderForward :: (Storable a)
+                     => MutableMacroBlock s a
+                     -> MutableMacroBlock s a
+                     -> ST s (MutableMacroBlock s a)
+{-# SPECIALIZE INLINE zigZagReorderForward :: MutableMacroBlock s Int32
+                                           -> MutableMacroBlock s Int32
+                                           -> ST s (MutableMacroBlock s Int32) #-}
+{-# SPECIALIZE INLINE zigZagReorderForward :: MutableMacroBlock s Int16
+                                           -> MutableMacroBlock s Int16
+                                           -> ST s (MutableMacroBlock s Int16) #-}
+{-# SPECIALIZE INLINE zigZagReorderForward :: MutableMacroBlock s Word8
+                                           -> MutableMacroBlock s Word8
+                                           -> ST s (MutableMacroBlock s Word8) #-}
+zigZagReorderForward zigzaged block = ordering zigZagOrderForward >> return zigzaged
+  where ordering !table = reorder (0 :: Int)
+          where reorder !i | i >= 64 = return ()
+                reorder i  = do
+                     let idx = table `VS.unsafeIndex` i
+                     v <- block `M.unsafeRead` idx
+                     (zigzaged `M.unsafeWrite` i) v
+                     reorder (i + 1)
+
+zigZagReorder :: MutableMacroBlock s Int16 -> MutableMacroBlock s Int16
+              -> ST s (MutableMacroBlock s Int16)
+zigZagReorder zigzaged block = do
+    let update i =  do
+            let idx = zigZagOrder `VS.unsafeIndex` i
+            v <- block `M.unsafeRead` idx
+            (zigzaged `M.unsafeWrite` i) v
+
+        reorder 63 = update 63
+        reorder i  = update i >> reorder (i + 1)
+
+    reorder (0 :: Int)
+    return zigzaged
+
+-- | Unpack an int of the given size encoded from MSB to LSB.
+unpackInt :: Int -> BoolReader s Int32
+unpackInt = getNextIntJpg
+
+{-# INLINE rasterMap #-}
+rasterMap :: (Monad m)
+          => Int -> Int -> (Int -> Int -> m ())
+          -> m ()
+rasterMap width height f = liner 0
+  where liner y | y >= height = return ()
+        liner y = columner 0
+          where columner x | x >= width = liner (y + 1)
+                columner x = f x y >> columner (x + 1)
+
+pixelClamp :: Int16 -> Word8
+pixelClamp n = fromIntegral . min 255 $ max 0 n
+
+-- | Given a size coefficient (how much a pixel span horizontally
+-- and vertically), the position of the macroblock, return a list
+-- of indices and value to be stored in an array (like the final
+-- image)
+unpackMacroBlock :: Int    -- ^ Component count
+                 -> Int -- ^ Width coefficient
+                 -> Int -- ^ Height coefficient
+                 -> Int -- ^ Component index
+                 -> Int -- ^ x
+                 -> Int -- ^ y
+                 -> MutableImage s PixelYCbCr8
+                 -> MutableMacroBlock s Int16
+                 -> ST s ()
+unpackMacroBlock compCount wCoeff hCoeff compIdx x y
+                 (MutableImage { mutableImageWidth = imgWidth,
+                                 mutableImageHeight = imgHeight, mutableImageData = img })
+                 block = rasterMap dctBlockSize dctBlockSize unpacker
+  where unpacker i j = do
+          let yBase = y * dctBlockSize + j * hCoeff
+          compVal <- pixelClamp <$> (block `M.unsafeRead` (i + j * dctBlockSize))
+          rasterMap wCoeff hCoeff $ \wDup hDup -> do
+             let xBase = x * dctBlockSize + i * wCoeff
+                 xPos = xBase + wDup
+                 yPos = yBase + hDup
+
+             when (xPos < imgWidth && yPos < imgHeight)
+                  (do let mutableIdx = (xPos + yPos * imgWidth) * compCount + compIdx
+                      (img `M.unsafeWrite` mutableIdx) compVal)
+
+-- | This is one of the most important function of the decoding,
+-- it form the barebone decoding pipeline for macroblock. It's all
+-- there is to know for macro block transformation
+decodeMacroBlock :: MacroBlock DctCoefficients
+                 -> MutableMacroBlock s Int16
+                 -> MutableMacroBlock s Int16
+                 -> ST s (MutableMacroBlock s Int16)
+decodeMacroBlock quantizationTable zigZagBlock block =
+    deQuantize quantizationTable block >>= zigZagReorder zigZagBlock
+                                       >>= inverseDirectCosineTransform
+
+ src/Codec/Picture/Jpg/Internal/DefaultTable.hs view
@@ -0,0 +1,298 @@+{-# LANGUAGE DeriveGeneric #-}
+{-# LANGUAGE TupleSections #-}
+{-# LANGUAGE FlexibleContexts #-}
+-- | Module used by the jpeg decoder internally, shouldn't be used
+-- in user code.
+module Codec.Picture.Jpg.Internal.DefaultTable( DctComponent( .. )
+                                     , HuffmanTree( .. )
+                                     , HuffmanTable
+                                     , HuffmanPackedTree
+                                     , MacroBlock
+                                     , QuantificationTable
+                                     , HuffmanWriterCode 
+                                     , scaleQuantisationMatrix
+                                     , makeMacroBlock
+                                     , makeInverseTable
+                                     , buildHuffmanTree
+                                     , packHuffmanTree
+                                     , huffmanPackedDecode
+
+                                     , defaultChromaQuantizationTable
+
+                                     , defaultLumaQuantizationTable
+
+                                     , defaultAcChromaHuffmanTree
+                                     , defaultAcChromaHuffmanTable
+
+                                     , defaultAcLumaHuffmanTree 
+                                     , defaultAcLumaHuffmanTable 
+
+                                     , defaultDcChromaHuffmanTree 
+                                     , defaultDcChromaHuffmanTable
+
+                                     , defaultDcLumaHuffmanTree
+                                     , defaultDcLumaHuffmanTable
+                                     ) where
+
+import Control.DeepSeq( NFData(..) )
+import Data.Int( Int16 )
+import Foreign.Storable ( Storable )
+import Control.Monad.ST( runST )
+import qualified Data.Vector.Storable as SV
+import qualified Data.Vector as V
+import Data.Bits( unsafeShiftL, (.|.), (.&.) )
+import Data.Word( Word8, Word16 )
+import Data.List( foldl' )
+import qualified Data.Vector.Storable.Mutable as M
+import GHC.Generics( Generic )
+
+import Codec.Picture.BitWriter
+
+-- | Tree storing the code used for huffman encoding.
+data HuffmanTree = Branch HuffmanTree HuffmanTree -- ^ If bit is 0 take the first subtree, if 1, the right.
+                 | Leaf Word8       -- ^ We should output the value
+                 | Empty            -- ^ no value present
+                 deriving (Eq, Show)
+
+type HuffmanPackedTree = SV.Vector Word16
+
+type HuffmanWriterCode = V.Vector (Word8, Word16)
+
+packHuffmanTree :: HuffmanTree -> HuffmanPackedTree
+packHuffmanTree tree = runST $ do
+    table <- M.replicate 512 0x8000
+    let aux (Empty) idx = return $ idx + 1
+        aux (Leaf v) idx = do
+            (table `M.unsafeWrite` idx) $ fromIntegral v .|. 0x4000
+            return $ idx + 1
+
+        aux (Branch i1@(Leaf _) i2@(Leaf _)) idx =
+            aux i1 idx >>= aux i2
+
+        aux (Branch i1@(Leaf _) i2) idx = do
+            _ <- aux i1 idx
+            ix2 <- aux i2 $ idx + 2
+            (table `M.unsafeWrite` (idx + 1)) $ fromIntegral $ idx + 2
+            return ix2
+
+        aux (Branch i1 i2@(Leaf _)) idx = do
+            ix1 <- aux i1 (idx + 2)
+            _ <- aux i2 (idx + 1)
+            (table `M.unsafeWrite` idx) . fromIntegral $ idx + 2
+            return ix1
+
+        aux (Branch i1 i2) idx = do
+            ix1 <- aux i1 (idx + 2)
+            ix2 <- aux i2 ix1
+            (table `M.unsafeWrite` idx) (fromIntegral $ idx + 2)
+            (table `M.unsafeWrite` (idx + 1)) (fromIntegral ix1)
+            return ix2
+    _ <- aux tree 0
+    SV.unsafeFreeze table
+
+makeInverseTable :: HuffmanTree -> HuffmanWriterCode
+makeInverseTable t = V.replicate 255 (0,0) V.// inner 0 0 t
+  where inner _     _     Empty   = []
+        inner depth code (Leaf v) = [(fromIntegral v, (depth, code))]
+        inner depth code (Branch l r) =
+          inner (depth + 1) shifted l ++ inner (depth + 1) (shifted .|. 1) r
+            where shifted = code `unsafeShiftL` 1
+
+-- | Represent a compact array of 8 * 8 values. The size
+-- is not guarenteed by type system, but if makeMacroBlock is
+-- used, everything should be fine size-wise
+type MacroBlock a = SV.Vector a
+
+type QuantificationTable = MacroBlock Int16
+
+-- | Helper function to create pure macro block of the good size.
+makeMacroBlock :: (Storable a) => [a] -> MacroBlock a
+makeMacroBlock = SV.fromListN 64
+
+-- | Enumeration used to search in the tables for different components.
+data DctComponent = DcComponent | AcComponent
+    deriving (Eq, Show, Generic)
+instance NFData DctComponent
+
+-- | Transform parsed coefficients from the jpeg header to a
+-- tree which can be used to decode data.
+buildHuffmanTree :: [[Word8]] -> HuffmanTree
+buildHuffmanTree table = foldl' insertHuffmanVal Empty
+                       . concatMap (\(i, t) -> map (i + 1,) t)
+                       $ zip ([0..] :: [Int]) table
+  where isTreeFullyDefined Empty = False
+        isTreeFullyDefined (Leaf _) = True
+        isTreeFullyDefined (Branch l r) = isTreeFullyDefined l && isTreeFullyDefined r
+
+        insertHuffmanVal Empty (0, val) = Leaf val
+        insertHuffmanVal Empty (d, val) = Branch (insertHuffmanVal Empty (d - 1, val)) Empty
+        insertHuffmanVal (Branch l r) (d, val)
+            | isTreeFullyDefined l = Branch l (insertHuffmanVal r (d - 1, val))
+            | otherwise            = Branch (insertHuffmanVal l (d - 1, val)) r
+        insertHuffmanVal (Leaf _) _ = error "Inserting in value, shouldn't happen"
+
+scaleQuantisationMatrix :: Int -> QuantificationTable -> QuantificationTable 
+scaleQuantisationMatrix quality
+    | quality < 0 = scaleQuantisationMatrix 0
+        -- shouldn't show much difference than with 1,
+        -- but hey, at least we're complete
+    | quality == 0 = SV.map (scale (10000 :: Int))
+    | quality < 50 = let qq = 5000 `div` quality
+                     in SV.map (scale qq)
+    | otherwise    = SV.map (scale q)
+          where q = 200 - quality * 2
+                scale coeff i = fromIntegral . min 255 
+                                             . max 1 
+                                             $ fromIntegral i * coeff `div` 100
+
+huffmanPackedDecode :: HuffmanPackedTree -> BoolReader s Word8
+huffmanPackedDecode table = getNextBitJpg >>= aux 0
+  where aux idx b
+            | (v .&. 0x8000) /= 0 = return  0
+            | (v .&. 0x4000) /= 0 = return . fromIntegral $ v .&. 0xFF
+            | otherwise = getNextBitJpg >>= aux v
+          where tableIndex | b = idx + 1
+                           | otherwise = idx
+                v = table `SV.unsafeIndex` fromIntegral tableIndex
+
+defaultLumaQuantizationTable :: QuantificationTable
+defaultLumaQuantizationTable = makeMacroBlock
+    [16, 11, 10, 16,  24,  40,  51,  61
+    ,12, 12, 14, 19,  26,  58,  60,  55
+    ,14, 13, 16, 24,  40,  57,  69,  56
+    ,14, 17, 22, 29,  51,  87,  80,  62
+    ,18, 22, 37, 56,  68, 109, 103,  77
+    ,24, 35, 55, 64,  81, 104, 113,  92
+    ,49, 64, 78, 87, 103, 121, 120, 101
+    ,72, 92, 95, 98, 112, 100, 103,  99
+    ]
+
+defaultChromaQuantizationTable :: QuantificationTable
+defaultChromaQuantizationTable = makeMacroBlock
+    [17, 18, 24, 47, 99, 99, 99, 99
+    ,18, 21, 26, 66, 99, 99, 99, 99
+    ,24, 26, 56, 99, 99, 99, 99, 99
+    ,47, 66, 99, 99, 99, 99, 99, 99
+    ,99, 99, 99, 99, 99, 99, 99, 99
+    ,99, 99, 99, 99, 99, 99, 99, 99
+    ,99, 99, 99, 99, 99, 99, 99, 99
+    ,99, 99, 99, 99, 99, 99, 99, 99
+    ]
+
+defaultDcLumaHuffmanTree :: HuffmanTree
+defaultDcLumaHuffmanTree = buildHuffmanTree defaultDcLumaHuffmanTable
+
+-- | From the Table K.3 of ITU-81 (p153)
+defaultDcLumaHuffmanTable :: HuffmanTable
+defaultDcLumaHuffmanTable =
+    [ []
+    , [0]
+    , [1, 2, 3, 4, 5]
+    , [6]
+    , [7]
+    , [8]
+    , [9]
+    , [10]
+    , [11]
+    , []
+    , []
+    , []
+    , []
+    , []
+    , []
+    , []
+    ]
+
+defaultDcChromaHuffmanTree :: HuffmanTree
+defaultDcChromaHuffmanTree = buildHuffmanTree defaultDcChromaHuffmanTable
+
+-- | From the Table K.4 of ITU-81 (p153)
+defaultDcChromaHuffmanTable :: HuffmanTable
+defaultDcChromaHuffmanTable = 
+    [ []
+    , [0, 1, 2]
+    , [3]
+    , [4]
+    , [5]
+    , [6]
+    , [7]
+    , [8]
+    , [9]
+    , [10]
+    , [11]
+    , []
+    , []
+    , []
+    , []
+    , []
+    ]
+
+defaultAcLumaHuffmanTree :: HuffmanTree
+defaultAcLumaHuffmanTree = buildHuffmanTree defaultAcLumaHuffmanTable
+
+-- | From the Table K.5 of ITU-81 (p154)
+defaultAcLumaHuffmanTable :: HuffmanTable
+defaultAcLumaHuffmanTable =
+    [ []
+    , [0x01, 0x02]
+    , [0x03]
+    , [0x00, 0x04, 0x11]
+    , [0x05, 0x12, 0x21]
+    , [0x31, 0x41]
+    , [0x06, 0x13, 0x51, 0x61]
+    , [0x07, 0x22, 0x71]
+    , [0x14, 0x32, 0x81, 0x91, 0xA1]
+    , [0x08, 0x23, 0x42, 0xB1, 0xC1]
+    , [0x15, 0x52, 0xD1, 0xF0]
+    , [0x24, 0x33, 0x62, 0x72]
+    , []
+    , []
+    , [0x82]
+    , [0x09, 0x0A, 0x16, 0x17, 0x18, 0x19, 0x1A, 0x25, 0x26, 0x27, 0x28, 0x29, 0x2A, 0x34, 0x35
+      ,0x36, 0x37, 0x38, 0x39, 0x3A, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49, 0x4A, 0x53, 0x54
+      ,0x55, 0x56, 0x57, 0x58, 0x59, 0x5A, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69, 0x6A, 0x73
+      ,0x74, 0x75, 0x76, 0x77, 0x78, 0x79, 0x7A, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89, 0x8A
+      ,0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98, 0x99, 0x9A, 0xA2, 0xA3, 0xA4, 0xA5, 0xA6, 0xA7
+      ,0xA8, 0xA9, 0xAA, 0xB2, 0xB3, 0xB4, 0xB5, 0xB6, 0xB7, 0xB8, 0xB9, 0xBA, 0xC2, 0xC3, 0xC4
+      ,0xC5, 0xC6, 0xC7, 0xC8, 0xC9, 0xCA, 0xD2, 0xD3, 0xD4, 0xD5, 0xD6, 0xD7, 0xD8, 0xD9, 0xDA
+      ,0xE1, 0xE2, 0xE3, 0xE4, 0xE5, 0xE6, 0xE7, 0xE8, 0xE9, 0xEA, 0xF1, 0xF2, 0xF3, 0xF4, 0xF5
+      ,0xF6, 0xF7, 0xF8, 0xF9, 0xFA]
+    ]
+
+type HuffmanTable = [[Word8]]
+
+defaultAcChromaHuffmanTree :: HuffmanTree
+defaultAcChromaHuffmanTree = buildHuffmanTree defaultAcChromaHuffmanTable 
+
+defaultAcChromaHuffmanTable :: HuffmanTable
+defaultAcChromaHuffmanTable = 
+    [ []
+    , [0x00, 0x01]
+    , [0x02]
+    , [0x03, 0x11]
+    , [0x04, 0x05, 0x21, 0x31]
+    , [0x06, 0x12, 0x41, 0x51]
+    , [0x07, 0x61, 0x71]
+    , [0x13, 0x22, 0x32, 0x81]
+    , [0x08, 0x14, 0x42, 0x91, 0xA1, 0xB1, 0xC1]
+    , [0x09, 0x23, 0x33, 0x52, 0xF0]
+    , [0x15, 0x62, 0x72, 0xD1]
+    , [0x0A, 0x16, 0x24, 0x34]
+    , []
+    , [0xE1]
+    , [0x25, 0xF1]
+    , [ 0x17, 0x18, 0x19, 0x1A, 0x26, 0x27, 0x28, 0x29, 0x2A, 0x35
+      , 0x36, 0x37, 0x38, 0x39, 0x3A, 0x43, 0x44, 0x45, 0x46, 0x47
+      , 0x48, 0x49, 0x4A, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59
+      , 0x5A, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69, 0x6A, 0x73
+      , 0x74, 0x75, 0x76, 0x77, 0x78, 0x79, 0x7A, 0x82, 0x83, 0x84
+      , 0x85, 0x86, 0x87, 0x88, 0x89, 0x8A, 0x92, 0x93, 0x94, 0x95
+      , 0x96, 0x97, 0x98, 0x99, 0x9A, 0xA2, 0xA3, 0xA4, 0xA5, 0xA6
+      , 0xA7, 0xA8, 0xA9, 0xAA, 0xB2, 0xB3, 0xB4, 0xB5, 0xB6, 0xB7
+      , 0xB8, 0xB9, 0xBA, 0xC2, 0xC3, 0xC4, 0xC5, 0xC6, 0xC7, 0xC8
+      , 0xC9, 0xCA, 0xD2, 0xD3, 0xD4, 0xD5, 0xD6, 0xD7, 0xD8, 0xD9
+      , 0xDA, 0xE2, 0xE3, 0xE4, 0xE5, 0xE6, 0xE7, 0xE8, 0xE9, 0xEA
+      , 0xF2, 0xF3, 0xF4, 0xF5, 0xF6, 0xF7, 0xF8, 0xF9, 0xFA
+      ]
+    ]
+
+ src/Codec/Picture/Jpg/Internal/FastDct.hs view
@@ -0,0 +1,218 @@+{-# LANGUAGE CPP #-}
+{-# LANGUAGE TypeFamilies #-}
+module Codec.Picture.Jpg.Internal.FastDct( referenceDct, fastDctLibJpeg ) where
+
+#if !MIN_VERSION_base(4,8,0)
+import Control.Applicative( (<$>) )
+#endif
+
+import Data.Int( Int16, Int32 )
+import Data.Bits( unsafeShiftR, unsafeShiftL )
+import Control.Monad.ST( ST )
+
+import qualified Data.Vector.Storable.Mutable as M
+
+import Codec.Picture.Jpg.Internal.Types
+import Control.Monad( forM, forM_ )
+
+-- | Reference implementation of the DCT, directly implementing the formula
+-- of ITU-81. It's slow as hell, perform to many operations, but is accurate
+-- and a good reference point.
+referenceDct :: MutableMacroBlock s Int32
+             -> MutableMacroBlock s Int16
+             -> ST s (MutableMacroBlock s Int32)
+referenceDct workData block = do
+  forM_ [(u, v) | u <- [0 :: Int .. dctBlockSize - 1], v <- [0..dctBlockSize - 1]] $ \(u,v) -> do
+    val <- at (u,v)
+    (workData `M.unsafeWrite` (v * dctBlockSize + u)) . truncate $ (1 / 4) * c u * c v * val
+
+  return workData
+ where -- at :: (Int, Int) -> ST s Float
+   at (u,v) = do
+     toSum <-
+        forM [(x,y) | x <- [0..dctBlockSize - 1], y <- [0..dctBlockSize - 1 :: Int]] $ \(x,y) -> do
+            sample <- fromIntegral <$> (block `M.unsafeRead` (y * dctBlockSize + x))
+            return $ sample * cos ((2 * fromIntegral x + 1) * fromIntegral u * (pi :: Float)/ 16) 
+                            * cos ((2 * fromIntegral y + 1) * fromIntegral v * pi / 16)
+     return $ sum toSum
+
+   c 0 = 1 / sqrt 2
+   c _ = 1
+
+pASS1_BITS, cONST_BITS :: Int
+cONST_BITS = 13
+pASS1_BITS =  2
+
+
+fIX_0_298631336, fIX_0_390180644, fIX_0_541196100,
+    fIX_0_765366865, fIX_0_899976223, fIX_1_175875602,
+    fIX_1_501321110, fIX_1_847759065, fIX_1_961570560,
+    fIX_2_053119869, fIX_2_562915447, fIX_3_072711026 :: Int32
+fIX_0_298631336 = 2446    -- FIX(0.298631336) */
+fIX_0_390180644 = 3196    -- FIX(0.390180644) */
+fIX_0_541196100 = 4433    -- FIX(0.541196100) */
+fIX_0_765366865 = 6270    -- FIX(0.765366865) */
+fIX_0_899976223 = 7373    -- FIX(0.899976223) */
+fIX_1_175875602 = 9633    -- FIX(1.175875602) */
+fIX_1_501321110 = 12299    -- FIX(1.501321110) */
+fIX_1_847759065 = 15137    -- FIX(1.847759065) */
+fIX_1_961570560 = 16069    -- FIX(1.961570560) */
+fIX_2_053119869 = 16819    -- FIX(2.053119869) */
+fIX_2_562915447 = 20995    -- FIX(2.562915447) */
+fIX_3_072711026 = 25172    -- FIX(3.072711026) */
+
+cENTERJSAMPLE :: Int32
+cENTERJSAMPLE = 128
+
+-- | Fast DCT extracted from libjpeg
+fastDctLibJpeg :: MutableMacroBlock s Int32
+        -> MutableMacroBlock s Int16
+        -> ST s (MutableMacroBlock s Int32)
+fastDctLibJpeg workData sample_block = do
+ firstPass workData  0
+ secondPass workData 7
+ {-_ <- mutate (\_ a -> a `quot` 8) workData-}
+ return workData
+  where -- Pass 1: process rows.
+        -- Note results are scaled up by sqrt(8) compared to a true DCT;
+        -- furthermore, we scale the results by 2**PASS1_BITS.
+        firstPass         _ i | i == dctBlockSize = return ()
+        firstPass dataBlock i = do
+            let baseIdx = i * dctBlockSize
+                readAt idx = fromIntegral <$> sample_block `M.unsafeRead` (baseIdx + idx)
+                mult = (*)
+                writeAt idx = dataBlock `M.unsafeWrite` (baseIdx + idx)
+                writeAtPos idx n = (dataBlock `M.unsafeWrite` (baseIdx + idx))
+                                    (n `unsafeShiftR` (cONST_BITS - pASS1_BITS))
+
+            blk0 <- readAt 0
+            blk1 <- readAt 1
+            blk2 <- readAt 2
+            blk3 <- readAt 3
+            blk4 <- readAt 4
+            blk5 <- readAt 5
+            blk6 <- readAt 6
+            blk7 <- readAt 7
+
+            let tmp0 = blk0 + blk7
+                tmp1 = blk1 + blk6
+                tmp2 = blk2 + blk5
+                tmp3 = blk3 + blk4
+
+                tmp10 = tmp0 + tmp3
+                tmp12 = tmp0 - tmp3
+                tmp11 = tmp1 + tmp2
+                tmp13 = tmp1 - tmp2
+
+                tmp0' = blk0 - blk7
+                tmp1' = blk1 - blk6
+                tmp2' = blk2 - blk5
+                tmp3' = blk3 - blk4
+
+            -- Stage 4 and output
+            writeAt 0 $ (tmp10 + tmp11 - dctBlockSize * cENTERJSAMPLE) `unsafeShiftL` pASS1_BITS
+            writeAt 4 $ (tmp10 - tmp11) `unsafeShiftL` pASS1_BITS
+
+            let z1 = mult (tmp12 + tmp13) fIX_0_541196100
+                     + (1 `unsafeShiftL` (cONST_BITS - pASS1_BITS - 1))
+
+            writeAtPos 2 $ z1 + mult tmp12 fIX_0_765366865
+            writeAtPos 6 $ z1 - mult tmp13 fIX_1_847759065
+
+            let tmp10' = tmp0' + tmp3'
+                tmp11' = tmp1' + tmp2'
+                tmp12' = tmp0' + tmp2'
+                tmp13' = tmp1' + tmp3'
+                z1' = mult (tmp12' + tmp13') fIX_1_175875602 --  c3 */
+                        -- Add fudge factor here for final descale. */
+                        + (1 `unsafeShiftL` (cONST_BITS - pASS1_BITS-1))
+                tmp0'' = mult tmp0' fIX_1_501321110
+                tmp1'' = mult tmp1' fIX_3_072711026
+                tmp2'' = mult tmp2' fIX_2_053119869
+                tmp3'' = mult tmp3' fIX_0_298631336
+
+                tmp10'' = mult tmp10' (- fIX_0_899976223)
+                tmp11'' = mult tmp11' (- fIX_2_562915447)
+                tmp12'' = mult tmp12' (- fIX_0_390180644) + z1'
+                tmp13'' = mult tmp13' (- fIX_1_961570560) + z1'
+
+            writeAtPos 1 $ tmp0'' + tmp10'' + tmp12''
+            writeAtPos 3 $ tmp1'' + tmp11'' + tmp13''
+            writeAtPos 5 $ tmp2'' + tmp11'' + tmp12''
+            writeAtPos 7 $ tmp3'' + tmp10'' + tmp13''
+
+            firstPass dataBlock $ i + 1
+
+        -- Pass 2: process columns.
+        -- We remove the PASS1_BITS scaling, but leave the results scaled up
+        -- by an overall factor of 8.
+        secondPass :: M.STVector s Int32 -> Int -> ST s ()
+        secondPass _     (-1) = return ()
+        secondPass block i = do
+            let readAt idx = block `M.unsafeRead` ((7 - i) + idx * dctBlockSize)
+                mult = (*)
+                writeAt idx = block `M.unsafeWrite` (dctBlockSize * idx + (7 - i))
+                writeAtPos idx n = (block `M.unsafeWrite` (dctBlockSize * idx + (7 - i))) $ n `unsafeShiftR` (cONST_BITS + pASS1_BITS + 3)
+            blk0 <- readAt 0
+            blk1 <- readAt 1
+            blk2 <- readAt 2
+            blk3 <- readAt 3
+            blk4 <- readAt 4
+            blk5 <- readAt 5
+            blk6 <- readAt 6
+            blk7 <- readAt 7
+
+            let tmp0 = blk0 + blk7
+                tmp1 = blk1 + blk6
+                tmp2 = blk2 + blk5
+                tmp3 = blk3 + blk4
+
+                -- Add fudge factor here for final descale. */
+                tmp10 = tmp0 + tmp3 + (1 `unsafeShiftL` (pASS1_BITS-1))
+                tmp12 = tmp0 - tmp3
+                tmp11 = tmp1 + tmp2
+                tmp13 = tmp1 - tmp2
+
+                tmp0' = blk0 - blk7
+                tmp1' = blk1 - blk6
+                tmp2' = blk2 - blk5
+                tmp3' = blk3 - blk4
+
+            writeAt 0 $ (tmp10 + tmp11) `unsafeShiftR` (pASS1_BITS + 3)
+            writeAt 4 $ (tmp10 - tmp11) `unsafeShiftR` (pASS1_BITS + 3)
+
+            let z1 = mult (tmp12 + tmp13) fIX_0_541196100
+                    + (1 `unsafeShiftL` (cONST_BITS + pASS1_BITS - 1))
+
+            writeAtPos 2 $ z1 + mult tmp12 fIX_0_765366865
+            writeAtPos 6 $ z1 - mult tmp13 fIX_1_847759065
+
+            let tmp10' = tmp0' + tmp3'
+                tmp11' = tmp1' + tmp2'
+                tmp12' = tmp0' + tmp2'
+                tmp13' = tmp1' + tmp3'
+
+                z1' = mult (tmp12' + tmp13') fIX_1_175875602
+                    -- Add fudge factor here for final descale. */
+                   + 1 `unsafeShiftL` (cONST_BITS+pASS1_BITS-1);
+
+                tmp0''  = mult tmp0'    fIX_1_501321110
+                tmp1''  = mult tmp1'    fIX_3_072711026
+                tmp2''  = mult tmp2'    fIX_2_053119869
+                tmp3''  = mult tmp3'    fIX_0_298631336
+                tmp10'' = mult tmp10' (- fIX_0_899976223)
+                tmp11'' = mult tmp11' (- fIX_2_562915447)
+                tmp12'' = mult tmp12' (- fIX_0_390180644)
+                            + z1'
+                tmp13'' = mult tmp13' (- fIX_1_961570560)
+                            + z1'
+            writeAtPos 1 $ tmp0'' + tmp10'' + tmp12''
+            writeAtPos 3 $ tmp1'' + tmp11'' + tmp13''
+            writeAtPos 5 $ tmp2'' + tmp11'' + tmp12''
+            writeAtPos 7 $ tmp3'' + tmp10'' + tmp13''
+
+            secondPass block (i - 1)
+
+{-# ANN module "HLint: ignore Use camelCase" #-}
+{-# ANN module "HLint: ignore Reduce duplication" #-}
+
+ src/Codec/Picture/Jpg/Internal/FastIdct.hs view
@@ -0,0 +1,229 @@+{-# LANGUAGE FlexibleContexts #-}
+{-# LANGUAGE TypeFamilies #-}
+-- | Module providing a 'fast' implementation of IDCT
+--
+-- inverse two dimensional DCT, Chen-Wang algorithm       
+-- (cf. IEEE ASSP-32, pp. 803-816, Aug. 1984)             
+-- 32-bit integer arithmetic (8 bit coefficients)         
+-- 11 mults, 29 adds per DCT                              
+--                                      sE, 18.8.91       
+--
+-- coefficients extended to 12 bit for IEEE1180-1990      
+-- compliance                           sE,  2.1.94       
+--
+-- this code assumes >> to be a two's-complement arithmetic
+-- right shift: (-2)>>1 == -1 , (-3)>>1 == -2               
+module Codec.Picture.Jpg.Internal.FastIdct( MutableMacroBlock
+                                 , fastIdct
+                                 , mutableLevelShift
+                                 , createEmptyMutableMacroBlock
+                                 ) where
+
+import qualified Data.Vector.Storable as V
+import Control.Monad.ST( ST )
+import Data.Bits( unsafeShiftL, unsafeShiftR )
+import Data.Int( Int16 )
+import qualified Data.Vector.Storable.Mutable as M
+
+import Codec.Picture.Jpg.Internal.Types
+
+iclip :: V.Vector Int16
+iclip = V.fromListN 1024 [ val i| i <- [(-512) .. 511] ]
+    where val i | i < (-256) = -256
+                | i > 255    =  255
+                | otherwise  =  i
+
+data IDctStage = IDctStage { 
+        x0 :: {-# UNPACK #-} !Int,
+        x1 :: {-# UNPACK #-} !Int,
+        x2 :: {-# UNPACK #-} !Int,
+        x3 :: {-# UNPACK #-} !Int,
+        x4 :: {-# UNPACK #-} !Int,
+        x5 :: {-# UNPACK #-} !Int,
+        x6 :: {-# UNPACK #-} !Int,
+        x7 :: {-# UNPACK #-} !Int,
+        x8 :: {-# UNPACK #-} !Int
+    }
+
+w1, w2, w3, w5, w6, w7 :: Int
+w1 = 2841 -- 2048*sqrt(2)*cos(1*pi/16)
+w2 = 2676 -- 2048*sqrt(2)*cos(2*pi/16)
+w3 = 2408 -- 2048*sqrt(2)*cos(3*pi/16)
+w5 = 1609 -- 2048*sqrt(2)*cos(5*pi/16)
+w6 = 1108 -- 2048*sqrt(2)*cos(6*pi/16)
+w7 = 565  -- 2048*sqrt(2)*cos(7*pi/16)
+
+-- row (horizontal) IDCT
+--
+--           7                       pi         1
+-- dst[k] = sum c[l] * src[l] * cos( -- * ( k + - ) * l )
+--          l=0                      8          2
+--
+-- where: c[0]    = 128
+--        c[1..7] = 128*sqrt(2)
+idctRow :: MutableMacroBlock s Int16 -> Int ->  ST s ()
+idctRow blk idx = do
+  xx0 <- blk `M.unsafeRead` (0 + idx)
+  xx1 <- blk `M.unsafeRead` (4 + idx) 
+  xx2 <- blk `M.unsafeRead` (6 + idx)
+  xx3 <- blk `M.unsafeRead` (2 + idx)
+  xx4 <- blk `M.unsafeRead` (1 + idx)
+  xx5 <- blk `M.unsafeRead` (7 + idx)
+  xx6 <- blk `M.unsafeRead` (5 + idx)
+  xx7 <- blk `M.unsafeRead` (3 + idx)
+  let initialState = IDctStage { x0 = (fromIntegral xx0 `unsafeShiftL` 11) + 128
+                               , x1 =  fromIntegral xx1 `unsafeShiftL` 11
+                               , x2 =  fromIntegral xx2
+                               , x3 =  fromIntegral xx3
+                               , x4 =  fromIntegral xx4
+                               , x5 =  fromIntegral xx5
+                               , x6 =  fromIntegral xx6
+                               , x7 =  fromIntegral xx7
+                               , x8 = 0
+                               } 
+
+      firstStage c = c { x4 = x8'  + (w1 - w7) * x4 c
+                       , x5 = x8'  - (w1 + w7) * x5 c
+                       , x6 = x8'' - (w3 - w5) * x6 c
+                       , x7 = x8'' - (w3 + w5) * x7 c
+                       , x8 = x8''
+                       }
+          where x8' = w7 * (x4 c + x5 c)
+                x8'' = w3 * (x6 c + x7 c)
+
+      secondStage c = c { x0 = x0 c - x1 c
+                        , x8 = x0 c + x1 c 
+                        , x1 = x1''
+                        , x2 = x1' - (w2 + w6) * x2 c
+                        , x3 = x1' + (w2 - w6) * x3 c
+                        , x4 = x4 c - x6 c
+                        , x6 = x5 c + x7 c
+                        , x5 = x5 c - x7 c
+                        }
+            where x1'  = w6 * (x3 c + x2 c)
+                  x1'' = x4 c + x6 c
+
+      thirdStage c = c { x7 = x8 c + x3 c
+                       , x8 = x8 c - x3 c
+                       , x3 = x0 c + x2 c
+                       , x0 = x0 c - x2 c
+                       , x2 = (181 * (x4 c + x5 c) + 128) `unsafeShiftR` 8
+                       , x4 = (181 * (x4 c - x5 c) + 128) `unsafeShiftR` 8
+                       }
+      scaled c = c { x0 = (x7 c + x1 c) `unsafeShiftR` 8
+                   , x1 = (x3 c + x2 c) `unsafeShiftR` 8
+                   , x2 = (x0 c + x4 c) `unsafeShiftR` 8
+                   , x3 = (x8 c + x6 c) `unsafeShiftR` 8
+                   , x4 = (x8 c - x6 c) `unsafeShiftR` 8
+                   , x5 = (x0 c - x4 c) `unsafeShiftR` 8
+                   , x6 = (x3 c - x2 c) `unsafeShiftR` 8
+                   , x7 = (x7 c - x1 c) `unsafeShiftR` 8
+                   }
+      transformed = scaled . thirdStage . secondStage $ firstStage initialState
+
+  (blk `M.unsafeWrite` (0 + idx)) . fromIntegral $ x0 transformed
+  (blk `M.unsafeWrite` (1 + idx)) . fromIntegral $ x1 transformed
+  (blk `M.unsafeWrite` (2 + idx)) . fromIntegral $ x2 transformed
+  (blk `M.unsafeWrite` (3 + idx)) . fromIntegral $ x3 transformed
+  (blk `M.unsafeWrite` (4 + idx)) . fromIntegral $ x4 transformed
+  (blk `M.unsafeWrite` (5 + idx)) . fromIntegral $ x5 transformed
+  (blk `M.unsafeWrite` (6 + idx)) . fromIntegral $ x6 transformed
+  (blk `M.unsafeWrite` (7 + idx)) . fromIntegral $ x7 transformed
+
+-- column (vertical) IDCT
+--
+--             7                         pi         1
+-- dst[8*k] = sum c[l] * src[8*l] * cos( -- * ( k + - ) * l )
+--            l=0                        8          2
+--
+-- where: c[0]    = 1/1024
+--        c[1..7] = (1/1024)*sqrt(2)
+--
+idctCol :: MutableMacroBlock s Int16 -> Int -> ST s ()
+idctCol blk idx = do
+  xx0 <- blk `M.unsafeRead` (    0 + idx)
+  xx1 <- blk `M.unsafeRead` (8 * 4 + idx)
+  xx2 <- blk `M.unsafeRead` (8 * 6 + idx)
+  xx3 <- blk `M.unsafeRead` (8 * 2 + idx)
+  xx4 <- blk `M.unsafeRead` (8     + idx)
+  xx5 <- blk `M.unsafeRead` (8 * 7 + idx)
+  xx6 <- blk `M.unsafeRead` (8 * 5 + idx)
+  xx7 <- blk `M.unsafeRead` (8 * 3 + idx)
+  let initialState = IDctStage { x0 = (fromIntegral xx0 `unsafeShiftL` 8) + 8192
+                               , x1 =  fromIntegral xx1 `unsafeShiftL` 8
+                               , x2 =  fromIntegral xx2
+                               , x3 =  fromIntegral xx3
+                               , x4 =  fromIntegral xx4
+                               , x5 =  fromIntegral xx5
+                               , x6 =  fromIntegral xx6
+                               , x7 =  fromIntegral xx7
+                               , x8 = 0
+                               } 
+      firstStage c = c { x4 = (x8'  + (w1 - w7) * x4 c) `unsafeShiftR` 3
+                       , x5 = (x8'  - (w1 + w7) * x5 c) `unsafeShiftR` 3
+                       , x6 = (x8'' - (w3 - w5) * x6 c) `unsafeShiftR` 3
+                       , x7 = (x8'' - (w3 + w5) * x7 c) `unsafeShiftR` 3
+                       , x8 = x8''
+                       }
+          where x8'  = w7 * (x4 c + x5 c) + 4
+                x8'' = w3 * (x6 c + x7 c) + 4
+
+      secondStage c = c { x8 = x0 c + x1 c
+                        , x0 = x0 c - x1 c
+                        , x2 = (x1' - (w2 + w6) * x2 c) `unsafeShiftR` 3
+                        , x3 = (x1' + (w2 - w6) * x3 c) `unsafeShiftR` 3
+                        , x4 = x4 c - x6 c
+                        , x1 = x1''
+                        , x6 = x5 c + x7 c
+                        , x5 = x5 c - x7 c
+                        }
+          where x1'  = w6 * (x3 c + x2 c) + 4
+                x1'' = x4 c + x6 c
+  
+      thirdStage c = c { x7 = x8 c + x3 c
+                       , x8 = x8 c - x3 c
+                       , x3 = x0 c + x2 c
+                       , x0 = x0 c - x2 c
+                       , x2 = (181 * (x4 c + x5 c) + 128) `unsafeShiftR` 8
+                       , x4 = (181 * (x4 c - x5 c) + 128) `unsafeShiftR` 8
+                       }
+
+      clip i | i < 511 = if i > -512 then iclip `V.unsafeIndex` (i + 512)
+                                    else iclip `V.unsafeIndex` 0
+            
+             | otherwise = iclip `V.unsafeIndex` 1023
+
+      f = thirdStage . secondStage $ firstStage initialState
+  (blk `M.unsafeWrite` (idx + 8*0)) . clip $ (x7 f + x1 f) `unsafeShiftR` 14
+  (blk `M.unsafeWrite` (idx + 8  )) . clip $ (x3 f + x2 f) `unsafeShiftR` 14
+  (blk `M.unsafeWrite` (idx + 8*2)) . clip $ (x0 f + x4 f) `unsafeShiftR` 14
+  (blk `M.unsafeWrite` (idx + 8*3)) . clip $ (x8 f + x6 f) `unsafeShiftR` 14
+  (blk `M.unsafeWrite` (idx + 8*4)) . clip $ (x8 f - x6 f) `unsafeShiftR` 14
+  (blk `M.unsafeWrite` (idx + 8*5)) . clip $ (x0 f - x4 f) `unsafeShiftR` 14
+  (blk `M.unsafeWrite` (idx + 8*6)) . clip $ (x3 f - x2 f) `unsafeShiftR` 14
+  (blk `M.unsafeWrite` (idx + 8*7)) . clip $ (x7 f - x1 f) `unsafeShiftR` 14
+
+
+{-# INLINE fastIdct #-}
+-- | Algorithm to call to perform an IDCT, return the same
+-- block that the one given as input.
+fastIdct :: MutableMacroBlock s Int16
+         -> ST s (MutableMacroBlock s Int16)
+fastIdct block = rows 0
+  where rows 8 = cols 0
+        rows i = idctRow block (8 * i) >> rows (i + 1)
+
+        cols 8 = return block
+        cols i = idctCol block i >> cols (i + 1)
+
+{-# INLINE mutableLevelShift #-}
+-- | Perform a Jpeg level shift in a mutable fashion.
+mutableLevelShift :: MutableMacroBlock s Int16
+                  -> ST s (MutableMacroBlock s Int16)
+mutableLevelShift block = update 0
+  where update 64 = return block
+        update idx = do
+            val <- block `M.unsafeRead` idx
+            (block `M.unsafeWrite` idx) $ val + 128
+            update $ idx + 1
+
+ src/Codec/Picture/Jpg/Internal/Metadata.hs view
@@ -0,0 +1,41 @@+{-# LANGUAGE CPP #-}
+module Codec.Picture.Jpg.Internal.Metadata ( extractMetadatas, encodeMetadatas ) where
+
+#if !MIN_VERSION_base(4,8,0)
+import Control.Applicative( pure )
+import Data.Monoid( mempty )
+import Data.Word( Word )
+#endif
+
+import Data.Word( Word16 )
+import Data.Maybe( fromMaybe )
+import qualified Codec.Picture.Metadata as Met
+import Codec.Picture.Metadata( Metadatas )
+import Codec.Picture.Jpg.Internal.Types
+
+scalerOfUnit :: JFifUnit -> Met.Keys Word -> Word16 -> Metadatas -> Metadatas
+scalerOfUnit unit k v = case unit of
+  JFifUnitUnknown -> id
+  JFifPixelsPerInch -> Met.insert k (fromIntegral v)
+  JFifPixelsPerCentimeter ->
+    Met.insert k (Met.dotsPerCentiMeterToDotPerInch $ fromIntegral v)
+
+extractMetadatas :: JpgJFIFApp0 -> Metadatas
+extractMetadatas jfif = 
+    inserter Met.DpiX (_jfifDpiX jfif)
+        $ inserter Met.DpiY (_jfifDpiY jfif) mempty
+  where
+    inserter = scalerOfUnit $ _jfifUnit jfif
+
+
+encodeMetadatas :: Metadatas -> [JpgFrame]
+encodeMetadatas metas = fromMaybe [] $ do
+  dpiX <- Met.lookup Met.DpiX metas
+  dpiY <- Met.lookup Met.DpiY metas
+  pure . pure . JpgJFIF $ JpgJFIFApp0
+    { _jfifUnit      = JFifPixelsPerInch
+    , _jfifDpiX      = fromIntegral dpiX
+    , _jfifDpiY      = fromIntegral dpiY
+    , _jfifThumbnail = Nothing
+    }
+
+ src/Codec/Picture/Jpg/Internal/Progressive.hs view
@@ -0,0 +1,332 @@+{-# LANGUAGE TupleSections #-}
+{-# LANGUAGE TypeSynonymInstances #-}
+{-# LANGUAGE FlexibleInstances #-}
+{-# LANGUAGE ScopedTypeVariables #-}
+{-# LANGUAGE CPP #-}
+module Codec.Picture.Jpg.Internal.Progressive
+    ( JpgUnpackerParameter( .. )
+    , progressiveUnpack
+    ) where
+
+#if !MIN_VERSION_base(4,8,0)
+import Control.Applicative( pure, (<$>) )
+#endif
+
+import Control.Monad( when, unless, forM_ )
+import Control.Monad.ST( ST )
+import Control.Monad.Trans( lift )
+import Data.Bits( (.&.), (.|.), unsafeShiftL )
+import Data.Int( Int16, Int32 )
+import qualified Data.ByteString as B
+import qualified Data.ByteString.Lazy as L
+import qualified Data.Vector as V
+import qualified Data.Vector.Storable as VS
+import Data.Vector( (!) )
+import qualified Data.Vector.Mutable as M
+import qualified Data.Vector.Storable.Mutable as MS
+
+import Codec.Picture.Types
+import Codec.Picture.BitWriter
+import Codec.Picture.Jpg.Internal.Common
+import Codec.Picture.Jpg.Internal.Types
+import Codec.Picture.Jpg.Internal.DefaultTable
+
+createMcuLineIndices :: JpgComponent -> Int -> Int -> V.Vector (VS.Vector Int)
+createMcuLineIndices param imgWidth mcuWidth =
+ V.fromList $ VS.fromList <$> [indexSolo, indexMulti]
+  where compW = fromIntegral $ horizontalSamplingFactor param
+        compH = fromIntegral $ verticalSamplingFactor param
+        imageBlockSize = toBlockSize imgWidth
+
+        -- if the displayed MCU block is only displayed in half (like with
+        -- width 500 then we loose one macroblock of the MCU at the end of
+        -- the line. Previous implementation which naively used full mcu
+        -- was wrong. Only taking into account visible macroblocks
+        indexSolo = [base + x
+            | y <- [0 .. compH - 1]
+            , let base = y * mcuWidth * compW
+            , x <- [0 .. imageBlockSize - 1]]
+
+        indexMulti =
+            [(mcu + y * mcuWidth) * compW + x
+                | mcu <- [0 .. mcuWidth - 1]
+                , y <- [0 .. compH - 1]
+                , x <- [0 .. compW - 1] ]
+
+decodeFirstDC :: JpgUnpackerParameter
+              -> MS.STVector s Int16
+              -> MutableMacroBlock s Int16
+              -> Int32
+              -> BoolReader s Int32
+decodeFirstDC params dcCoeffs block eobrun = unpack >> pure eobrun
+  where unpack = do
+          (dcDeltaCoefficient) <- dcCoefficientDecode $ dcHuffmanTree params
+          previousDc <- lift $ dcCoeffs `MS.unsafeRead` componentIndex params
+          let neoDcCoefficient = previousDc + dcDeltaCoefficient
+              approxLow = fst $ successiveApprox params
+              scaledDc = neoDcCoefficient `unsafeShiftL` approxLow
+          lift $ (block `MS.unsafeWrite` 0) scaledDc 
+          lift $ (dcCoeffs `MS.unsafeWrite` componentIndex params) neoDcCoefficient
+
+decodeRefineDc :: JpgUnpackerParameter
+               -> a
+               -> MutableMacroBlock s Int16
+               -> Int32
+               -> BoolReader s Int32
+decodeRefineDc params _ block eobrun = unpack >> pure eobrun
+  where approxLow = fst $ successiveApprox params
+        plusOne = 1 `unsafeShiftL` approxLow
+        unpack = do
+            bit <- getNextBitJpg
+            when bit . lift $ do
+                v <- block `MS.unsafeRead` 0
+                (block `MS.unsafeWrite` 0) $ v .|. plusOne
+
+decodeFirstAc :: JpgUnpackerParameter
+              -> a
+              -> MutableMacroBlock s Int16
+              -> Int32
+              -> BoolReader s Int32
+decodeFirstAc _params _ _block eobrun | eobrun > 0 = pure $ eobrun - 1
+decodeFirstAc params _ block _ = unpack startIndex
+  where (startIndex, maxIndex) = coefficientRange params
+        (low, _) = successiveApprox params
+        unpack n | n > maxIndex = pure 0
+        unpack n = do
+            rrrrssss <- decodeRrrrSsss $ acHuffmanTree params
+            case rrrrssss of
+                (0xF, 0) -> unpack $ n + 16
+                (  0, 0) -> return 0
+                (  r, 0) -> eobrun <$> unpackInt r
+                    where eobrun lowBits = (1 `unsafeShiftL` r) - 1 + lowBits
+                (  r, s) -> do
+                    let n' = n + r
+                    val <- (`unsafeShiftL` low) <$> decodeInt s
+                    lift . (block `MS.unsafeWrite` n') $ fromIntegral val
+                    unpack $ n' + 1
+
+decodeRefineAc :: forall a s. JpgUnpackerParameter
+               -> a
+               -> MutableMacroBlock s Int16
+               -> Int32
+               -> BoolReader s Int32
+decodeRefineAc params _ block eobrun
+        | eobrun == 0 = unpack startIndex
+        | otherwise   = performEobRun startIndex >> return (eobrun - 1)
+  where (startIndex, maxIndex) = coefficientRange params
+        (low, _) = successiveApprox params
+        plusOne = 1 `unsafeShiftL` low
+        minusOne = (-1) `unsafeShiftL` low
+
+        getBitVal = do
+            v <- getNextBitJpg
+            pure $ if v then plusOne else minusOne
+
+        performEobRun idx | idx > maxIndex = pure ()
+        performEobRun idx = do
+          coeff <- lift $ block `MS.unsafeRead` idx
+          if coeff /= 0 then do
+            bit <- getNextBitJpg
+            case (bit, (coeff .&. plusOne) == 0) of
+               (False, _)    -> performEobRun $ idx + 1
+               (True, False) -> performEobRun $ idx + 1
+               (True, True) -> do
+                   let newVal | coeff >= 0 = coeff + plusOne
+                              | otherwise = coeff + minusOne
+                   lift $ (block `MS.unsafeWrite` idx) newVal
+                   performEobRun $ idx + 1
+          else
+            performEobRun $ idx + 1
+
+        unpack idx | idx > maxIndex = pure 0
+        unpack idx = do
+            rrrrssss <- decodeRrrrSsss $ acHuffmanTree params
+            case rrrrssss of
+              (0xF, 0) -> do
+                idx' <- updateCoeffs 0xF idx
+                unpack $ idx' + 1
+
+              (  r, 0) -> do
+                  lowBits <- unpackInt r
+                  let newEobRun = (1 `unsafeShiftL` r) + lowBits - 1
+                  performEobRun idx
+                  pure newEobRun
+
+              (  r, _) -> do
+                  val <- getBitVal
+                  idx' <- updateCoeffs (fromIntegral r) idx
+                  when (idx' <= maxIndex) $
+                       lift $ (block `MS.unsafeWrite` idx') val
+                  unpack $ idx' + 1
+
+        updateCoeffs :: Int -> Int -> BoolReader s Int
+        updateCoeffs r idx
+            | r   < 0        = pure $ idx - 1
+            | idx > maxIndex = pure idx
+        updateCoeffs r idx = do
+          coeff <- lift $ block `MS.unsafeRead` idx
+          if coeff /= 0 then do
+            bit <- getNextBitJpg
+            when (bit && coeff .&. plusOne == 0) $ do
+              let writeCoeff | coeff >= 0 = coeff + plusOne
+                             | otherwise = coeff + minusOne
+              lift $ (block `MS.unsafeWrite` idx) writeCoeff
+            updateCoeffs r $ idx + 1
+          else
+            updateCoeffs (r - 1) $ idx + 1
+
+type Unpacker s =
+    JpgUnpackerParameter -> MS.STVector s Int16 -> MutableMacroBlock s Int16 -> Int32
+        -> BoolReader s Int32
+
+
+prepareUnpacker :: [([(JpgUnpackerParameter, a)], L.ByteString)]
+                -> ST s ( V.Vector (V.Vector (JpgUnpackerParameter, Unpacker s))
+                        , M.STVector s BoolState)
+prepareUnpacker lst = do
+    let boolStates = V.fromList $ map snd infos
+    vec <- V.unsafeThaw boolStates
+    return (V.fromList $ map fst infos, vec)
+  where infos = map prepare lst
+        prepare ([], _) = error "progressiveUnpack, no component"
+        prepare (whole@((param, _) : _) , byteString) =
+         (V.fromList $ map (\(p,_) -> (p, unpacker)) whole, boolReader)
+           where unpacker = selection (successiveApprox param) (coefficientRange param)
+                 boolReader = initBoolStateJpg . B.concat $ L.toChunks byteString
+
+                 selection (_, 0) (0, _) = decodeFirstDC
+                 selection (_, 0) _      = decodeFirstAc
+                 selection _      (0, _) = decodeRefineDc
+                 selection _      _      = decodeRefineAc
+
+data ComponentData s = ComponentData
+  { componentIndices    :: V.Vector (VS.Vector Int)
+  , componentBlocks     :: V.Vector (MutableMacroBlock s Int16)
+  , componentId         :: !Int
+  , componentBlockCount :: !Int
+  }
+
+-- | Iteration from 0 to n in monadic context, without data
+-- keeping.
+lineMap :: (Monad m) => Int -> (Int -> m ()) -> m ()
+{-# INLINE lineMap #-}
+lineMap count f = go 0
+  where go n | n >= count = return ()
+        go n = f n >> go (n + 1)
+
+progressiveUnpack :: (Int, Int)
+                  -> JpgFrameHeader
+                  -> V.Vector (MacroBlock Int16)
+                  -> [([(JpgUnpackerParameter, a)], L.ByteString)]
+                  -> ST s (MutableImage s PixelYCbCr8)
+progressiveUnpack (maxiW, maxiH) frame quants lst = do
+    (unpackers, readers) <- prepareUnpacker lst
+    allBlocks <- mapM allocateWorkingBlocks . zip [0..] $ jpgComponents frame
+                    :: ST s [ComponentData s]
+    let scanCount = length lst
+        restartIntervalValue = case lst of
+                ((p,_):_,_): _ -> restartInterval p
+                _ -> -1
+    dcCoeffs <- MS.replicate imgComponentCount 0
+    eobRuns <- MS.replicate (length lst) 0
+    workBlock <- createEmptyMutableMacroBlock
+    writeIndices <- MS.replicate imgComponentCount (0 :: Int)
+    restartIntervals <- MS.replicate scanCount restartIntervalValue
+    let elementCount = imgWidth * imgHeight * fromIntegral imgComponentCount
+    img <- MutableImage imgWidth imgHeight <$> MS.replicate elementCount 128
+
+    let processRestartInterval =
+          forM_ [0 .. scanCount - 1] $ \ix -> do
+            v <- restartIntervals `MS.read` ix
+            if v == 0 then do
+              -- reset DC prediction
+              when (ix == 0) (MS.set dcCoeffs 0)
+              reader <- readers `M.read` ix
+              (_, updated) <- runBoolReaderWith reader $
+                  byteAlignJpg >> decodeRestartInterval
+              (readers `M.write` ix) updated 
+              (eobRuns `MS.unsafeWrite` ix) 0
+              (restartIntervals `MS.unsafeWrite` ix) $ restartIntervalValue - 1
+            else
+              (restartIntervals `MS.unsafeWrite` ix) $ v - 1
+
+
+    lineMap imageMcuHeight $ \mmY -> do
+      -- Reset all blocks to 0
+      forM_ allBlocks $ V.mapM_ (`MS.set` 0) .  componentBlocks
+      MS.set writeIndices 0
+
+      lineMap imageMcuWidth $ \_mmx -> do
+        processRestartInterval 
+        V.forM_ unpackers $ V.mapM_ $ \(unpackParam, unpacker) -> do
+            boolState <- readers `M.read` readerIndex unpackParam
+            eobrun <- eobRuns `MS.read` readerIndex unpackParam
+            let componentNumber = componentIndex unpackParam
+            writeIndex <- writeIndices `MS.read` componentNumber
+            let componentData = allBlocks !! componentNumber
+                -- We get back the correct block indices for the number of component
+                -- in the current scope (precalculated)
+                indexVector =
+                    componentIndices componentData ! indiceVector unpackParam
+                maxIndexLength = VS.length indexVector
+            unless (writeIndex + blockIndex unpackParam >= maxIndexLength) $ do
+               let realIndex = indexVector VS.! (writeIndex + blockIndex unpackParam)
+                   writeBlock = componentBlocks componentData ! realIndex
+               (eobrun', state) <-
+                   runBoolReaderWith boolState $
+                       unpacker unpackParam dcCoeffs writeBlock eobrun
+
+               (readers `M.write` readerIndex unpackParam) state
+               (eobRuns `MS.write` readerIndex unpackParam) eobrun'
+
+        -- Update the write indices
+        forM_ allBlocks $ \comp -> do
+          writeIndex <- writeIndices `MS.read` componentId comp
+          let newIndex = writeIndex + componentBlockCount comp
+          (writeIndices `MS.write` componentId comp) newIndex
+
+      forM_ allBlocks $ \compData -> do
+        let compBlocks = componentBlocks compData
+            cId = componentId compData
+            comp = jpgComponents frame !! cId
+            quantId =
+                fromIntegral $ quantizationTableDest comp
+            table = quants ! min 3 quantId
+            compW = fromIntegral $ horizontalSamplingFactor comp
+            compH = fromIntegral $ verticalSamplingFactor comp
+            cw8 = maxiW - fromIntegral (horizontalSamplingFactor comp) + 1
+            ch8 = maxiH - fromIntegral (verticalSamplingFactor comp) + 1
+
+        rasterMap (imageMcuWidth * compW) compH $ \rx y -> do
+            let ry = mmY * maxiH + y
+                block = compBlocks ! (y * imageMcuWidth * compW + rx)
+            transformed <- decodeMacroBlock table workBlock block
+            unpackMacroBlock imgComponentCount
+                    cw8 ch8 cId (rx * cw8) ry
+                    img transformed
+
+    return img
+
+  where imgComponentCount = length $ jpgComponents frame
+
+        imgWidth = fromIntegral $ jpgWidth frame
+        imgHeight = fromIntegral $ jpgHeight frame
+
+        imageBlockWidth = toBlockSize imgWidth
+        imageBlockHeight = toBlockSize imgHeight
+
+        imageMcuWidth =  (imageBlockWidth + (maxiW - 1)) `div` maxiW
+        imageMcuHeight = (imageBlockHeight + (maxiH - 1)) `div` maxiH
+
+        allocateWorkingBlocks (ix, comp) = do
+            let blockCount = hSample * vSample * imageMcuWidth * 2
+            blocks <- V.replicateM blockCount createEmptyMutableMacroBlock
+            return ComponentData 
+                { componentBlocks = blocks
+                , componentIndices = createMcuLineIndices comp imgWidth imageMcuWidth
+                , componentBlockCount = hSample * vSample
+                , componentId = ix
+                }
+            where hSample = fromIntegral $ horizontalSamplingFactor comp
+                  vSample = fromIntegral $ verticalSamplingFactor comp
+
+ src/Codec/Picture/Jpg/Internal/Types.hs view
@@ -0,0 +1,1073 @@+{-# LANGUAGE BangPatterns #-}
+{-# LANGUAGE DeriveGeneric #-}
+{-# LANGUAGE ScopedTypeVariables #-}
+{-# LANGUAGE TypeFamilies #-}
+{-# LANGUAGE CPP #-}
+
+-- | A good explanation of the JPEG format, including diagrams, is given at:
+-- <https://github.com/corkami/formats/blob/master/image/jpeg.md>
+--
+-- The full spec (excluding EXIF): https://www.w3.org/Graphics/JPEG/itu-t81.pdf
+module Codec.Picture.Jpg.Internal.Types( MutableMacroBlock
+                              , createEmptyMutableMacroBlock
+                              , printMacroBlock
+                              , printPureMacroBlock
+                              , DcCoefficient
+                              , JpgImage( .. )
+                              , JpgComponent( .. )
+                              , JpgFrameHeader( .. )
+                              , JpgFrame( .. )
+                              , JpgFrameKind( .. )
+                              , JpgScanHeader( .. )
+                              , JpgQuantTableSpec( .. )
+                              , JpgHuffmanTableSpec( .. )
+                              , JpgImageKind( .. )
+                              , JpgScanSpecification( .. )
+                              , JpgColorSpace( .. )
+                              , AdobeTransform( .. )
+                              , JpgAdobeApp14( .. )
+                              , JpgJFIFApp0( .. )
+                              , JFifUnit( .. )
+                              , TableList( .. )
+                              , RestartInterval( .. )
+                              , getJpgImage
+                              , calculateSize
+                              , dctBlockSize
+                              , parseECS
+                              , parseECS_simple
+                              , skipUntilFrames
+                              , skipFrameMarker
+                              , parseFrameOfKind
+                              , parseFrames
+                              , parseFrameKinds
+                              , parseToFirstFrameHeader
+                              ) where
+
+
+#if !MIN_VERSION_base(4,8,0)
+import Control.Applicative( pure, (<*>), (<$>) )
+#endif
+
+import Control.DeepSeq( NFData(..) )
+import Control.Monad( when, replicateM, forM, forM_, unless )
+import Control.Monad.ST( ST )
+import Data.Bits( (.|.), (.&.), unsafeShiftL, unsafeShiftR )
+import Data.List( partition )
+import Data.Maybe( maybeToList )
+import GHC.Generics( Generic )
+
+#if !MIN_VERSION_base(4,11,0)
+import Data.Monoid( (<>) )
+#endif
+
+import Foreign.Storable ( Storable )
+import Data.Vector.Unboxed( (!) )
+import qualified Data.Vector as V
+import qualified Data.Vector.Unboxed as VU
+import qualified Data.Vector.Storable as VS
+import qualified Data.Vector.Storable.Mutable as M
+import qualified Data.ByteString as B
+import qualified Data.ByteString.Char8 as BC
+import qualified Data.ByteString.Lazy as L
+import qualified Data.ByteString.Unsafe as BU
+
+import Data.Int( Int16, Int64 )
+import Data.Word(Word8, Word16 )
+import Data.Binary( Binary(..) )
+
+import Data.Binary.Get( Get
+                      , getWord8
+                      , getWord16be
+                      , getByteString
+                      , skip
+                      , bytesRead
+                      , lookAhead
+                      , ByteOffset
+                      , getLazyByteString
+                      )
+import qualified Data.Binary.Get.Internal as GetInternal
+
+import Data.Binary.Put( Put
+                      , putWord8
+                      , putWord16be
+                      , putLazyByteString
+                      , putByteString
+                      , runPut
+                      )
+
+import Codec.Picture.InternalHelper
+import Codec.Picture.Jpg.Internal.DefaultTable
+import Codec.Picture.Tiff.Internal.Types
+import Codec.Picture.Tiff.Internal.Metadata( exifOffsetIfd )
+import Codec.Picture.Metadata.Exif
+
+import Text.Printf
+
+-- | Type only used to make clear what kind of integer we are carrying
+-- Might be transformed into newtype in the future
+type DcCoefficient = Int16
+
+-- | Macroblock that can be transformed.
+type MutableMacroBlock s a = M.STVector s a
+
+data JpgFrameKind =
+      JpgBaselineDCTHuffman
+    | JpgExtendedSequentialDCTHuffman
+    | JpgProgressiveDCTHuffman
+    | JpgLosslessHuffman
+    | JpgDifferentialSequentialDCTHuffman
+    | JpgDifferentialProgressiveDCTHuffman
+    | JpgDifferentialLosslessHuffman
+    | JpgExtendedSequentialArithmetic
+    | JpgProgressiveDCTArithmetic
+    | JpgLosslessArithmetic
+    | JpgDifferentialSequentialDCTArithmetic
+    | JpgDifferentialProgressiveDCTArithmetic
+    | JpgDifferentialLosslessArithmetic
+    | JpgQuantizationTable
+    | JpgHuffmanTableMarker
+    | JpgStartOfScan
+    | JpgEndOfImage
+    | JpgAppSegment Word8
+    | JpgExtensionSegment Word8
+
+    | JpgRestartInterval
+    | JpgRestartIntervalEnd Word8
+    deriving (Eq, Show, Generic)
+instance NFData JpgFrameKind
+
+data JpgFrame =
+      JpgAppFrame        !Word8 B.ByteString
+    | JpgAdobeAPP14      !JpgAdobeApp14
+    | JpgJFIF            !JpgJFIFApp0
+    | JpgExif            ![ImageFileDirectory]
+    | JpgExtension       !Word8 B.ByteString
+    | JpgQuantTable      ![JpgQuantTableSpec]
+    | JpgHuffmanTable    ![(JpgHuffmanTableSpec, HuffmanPackedTree)]
+    | JpgScanBlob        !JpgScanHeader !L.ByteString -- ^ The @ByteString@ is the ECS (Entropy-Coded Segment), typically the largest part of compressed image data.
+    | JpgScans           !JpgFrameKind !JpgFrameHeader
+    | JpgIntervalRestart !Word16
+    deriving (Eq, Show, Generic)
+instance NFData JpgFrame
+
+data JpgColorSpace
+  = JpgColorSpaceYCbCr
+  | JpgColorSpaceYCC
+  | JpgColorSpaceY
+  | JpgColorSpaceYA
+  | JpgColorSpaceYCCA
+  | JpgColorSpaceYCCK
+  | JpgColorSpaceCMYK
+  | JpgColorSpaceRGB
+  | JpgColorSpaceRGBA
+  deriving (Eq, Show, Generic)
+instance NFData JpgColorSpace
+
+data AdobeTransform
+  = AdobeUnknown    -- ^ Value 0
+  | AdobeYCbCr      -- ^ value 1
+  | AdobeYCck       -- ^ value 2
+  deriving (Eq, Show, Generic)
+instance NFData AdobeTransform
+
+data JpgAdobeApp14 = JpgAdobeApp14
+  { _adobeDctVersion :: !Word16
+  , _adobeFlag0      :: !Word16
+  , _adobeFlag1      :: !Word16
+  , _adobeTransform  :: !AdobeTransform
+  }
+  deriving (Eq, Show, Generic)
+instance NFData JpgAdobeApp14
+
+-- | Size: 1
+data JFifUnit
+  = JFifUnitUnknown   -- ^ 0
+  | JFifPixelsPerInch -- ^ 1
+  | JFifPixelsPerCentimeter -- ^ 2
+  deriving (Eq, Show, Generic)
+instance NFData JFifUnit
+
+instance Binary JFifUnit where
+  put v = putWord8 $ case v of
+    JFifUnitUnknown -> 0
+    JFifPixelsPerInch -> 1
+    JFifPixelsPerCentimeter -> 2
+  get = do
+    v <- getWord8
+    pure $ case v of
+      0 -> JFifUnitUnknown
+      1 -> JFifPixelsPerInch
+      2 -> JFifPixelsPerCentimeter
+      _ -> JFifUnitUnknown
+
+data JpgJFIFApp0 = JpgJFIFApp0
+  { _jfifUnit      :: !JFifUnit
+  , _jfifDpiX      :: !Word16
+  , _jfifDpiY      :: !Word16
+  , _jfifThumbnail :: !(Maybe {- (Image PixelRGB8) -} Int)
+  }
+  deriving (Eq, Show, Generic)
+instance NFData JpgJFIFApp0
+
+instance Binary JpgJFIFApp0 where
+  get = do
+    sig <- getByteString 5
+    when (sig /= BC.pack "JFIF\0") $
+        fail "Invalid JFIF signature"
+    major <- getWord8
+    minor <- getWord8
+    when (major /= 1 && minor > 2) $
+        fail "Unrecognize JFIF version"
+    unit <- get
+    dpiX <- getWord16be
+    dpiY <- getWord16be
+    w <- getWord8
+    h <- getWord8
+    let pxCount = 3 * w * h
+    img <- case pxCount of
+      0 -> return Nothing
+      _ -> return Nothing
+    return $ JpgJFIFApp0
+        { _jfifUnit      = unit
+        , _jfifDpiX      = dpiX
+        , _jfifDpiY      = dpiY
+        , _jfifThumbnail = img
+        }
+
+
+  put jfif = do
+    putByteString $ BC.pack "JFIF\0" -- 5
+    putWord8 1                       -- 1 6
+    putWord8 2                       -- 1 7
+    put $ _jfifUnit jfif             -- 1 8
+    putWord16be $ _jfifDpiX jfif     -- 2 10
+    putWord16be $ _jfifDpiY jfif     -- 2 12
+    putWord8 0                       -- 1 13
+    putWord8 0                       -- 1 14
+
+{-Thumbnail width (tw) 	1 	Horizontal size of embedded JFIF thumbnail in pixels-}
+{-Thumbnail height (th) 	1 	Vertical size of embedded JFIF thumbnail in pixels-}
+{-Thumbnail data 	3 × tw × th 	Uncompressed 24 bit RGB raster thumbnail-}
+
+instance Binary AdobeTransform where
+  put v = case v of
+    AdobeUnknown -> putWord8 0
+    AdobeYCbCr -> putWord8 1
+    AdobeYCck -> putWord8 2
+
+  get = do
+    v <- getWord8
+    pure $ case v of
+      0 -> AdobeUnknown
+      1 -> AdobeYCbCr
+      2 -> AdobeYCck
+      _ -> AdobeUnknown
+
+instance Binary JpgAdobeApp14 where
+  get = do
+    let sig = BC.pack "Adobe"
+    fileSig <- getByteString 5
+    when (fileSig /= sig) $
+       fail "Invalid Adobe APP14 marker"
+    version <- getWord16be
+    when (version /= 100) $
+       fail $ "Invalid Adobe APP14 version " ++ show version
+    JpgAdobeApp14 version
+                  <$> getWord16be
+                  <*> getWord16be <*> get
+
+  put (JpgAdobeApp14 v f0 f1 t) = do
+    putByteString $ BC.pack "Adobe"
+    putWord16be v
+    putWord16be f0
+    putWord16be f1
+    put t
+
+
+data JpgFrameHeader = JpgFrameHeader
+    { jpgFrameHeaderLength   :: !Word16
+    , jpgSamplePrecision     :: !Word8
+    , jpgHeight              :: !Word16
+    , jpgWidth               :: !Word16
+    , jpgImageComponentCount :: !Word8
+    , jpgComponents          :: ![JpgComponent]
+    }
+    deriving (Eq, Show, Generic)
+instance NFData JpgFrameHeader
+
+
+instance SizeCalculable JpgFrameHeader where
+    calculateSize hdr = 2 + 1 + 2 + 2 + 1
+                      + sum [calculateSize c | c <- jpgComponents hdr]
+
+data JpgComponent = JpgComponent
+    { componentIdentifier       :: !Word8
+      -- | Stored with 4 bits
+    , horizontalSamplingFactor  :: !Word8
+      -- | Stored with 4 bits
+    , verticalSamplingFactor    :: !Word8
+    , quantizationTableDest     :: !Word8
+    }
+    deriving (Eq, Show, Generic)
+instance NFData JpgComponent
+
+instance SizeCalculable JpgComponent where
+    calculateSize _ = 3
+
+data JpgImage = JpgImage { jpgFrame :: [JpgFrame] }
+    deriving (Eq, Show, Generic)
+instance NFData JpgImage
+
+data JpgScanSpecification = JpgScanSpecification
+    { componentSelector :: !Word8
+      -- | Encoded as 4 bits
+    , dcEntropyCodingTable :: !Word8
+      -- | Encoded as 4 bits
+    , acEntropyCodingTable :: !Word8
+
+    }
+    deriving (Eq, Show, Generic)
+instance NFData JpgScanSpecification
+
+instance SizeCalculable JpgScanSpecification where
+    calculateSize _ = 2
+
+data JpgScanHeader = JpgScanHeader
+    { scanLength :: !Word16
+    , scanComponentCount :: !Word8
+    , scans :: [JpgScanSpecification]
+
+      -- | (begin, end)
+    , spectralSelection    :: (Word8, Word8)
+
+      -- | Encoded as 4 bits
+    , successiveApproxHigh :: !Word8
+
+      -- | Encoded as 4 bits
+    , successiveApproxLow :: !Word8
+    }
+    deriving (Eq, Show, Generic)
+instance NFData JpgScanHeader
+
+instance SizeCalculable JpgScanHeader where
+    calculateSize hdr = 2 + 1
+                      + sum [calculateSize c | c <- scans hdr]
+                      + 2
+                      + 1
+
+data JpgQuantTableSpec = JpgQuantTableSpec
+    { -- | Stored on 4 bits
+      quantPrecision     :: !Word8
+
+      -- | Stored on 4 bits
+    , quantDestination   :: !Word8
+
+    , quantTable         :: MacroBlock Int16
+    }
+    deriving (Eq, Show, Generic)
+instance NFData JpgQuantTableSpec
+
+class SizeCalculable a where
+    calculateSize :: a -> Int
+
+-- | Type introduced only to avoid some typeclass overlapping
+-- problem
+newtype TableList a = TableList [a]
+
+instance (SizeCalculable a, Binary a) => Binary (TableList a) where
+    put (TableList lst) = do
+        putWord16be . fromIntegral $ sum [calculateSize table | table <- lst] + 2
+        mapM_ put lst
+
+    get = TableList <$> (getWord16be >>= \s -> innerParse (fromIntegral s - 2))
+      where innerParse :: Int -> Get [a]
+            innerParse 0    = return []
+            innerParse size = do
+                onStart <- fromIntegral <$> bytesRead
+                table <- get
+                onEnd <- fromIntegral <$> bytesRead
+                (table :) <$> innerParse (size - (onEnd - onStart))
+
+instance SizeCalculable JpgQuantTableSpec where
+    calculateSize table =
+        1 + (fromIntegral (quantPrecision table) + 1) * 64
+
+instance Binary JpgQuantTableSpec where
+    put table = do
+        let precision = quantPrecision table
+        put4BitsOfEach precision (quantDestination table)
+        forM_ (VS.toList $ quantTable table) $ \coeff ->
+            if precision == 0 then putWord8 $ fromIntegral coeff
+                             else putWord16be $ fromIntegral coeff
+
+    get = do
+        (precision, dest) <- get4BitOfEach
+        coeffs <- replicateM 64 $ if precision == 0
+                then fromIntegral <$> getWord8
+                else fromIntegral <$> getWord16be
+        return JpgQuantTableSpec
+            { quantPrecision = precision
+            , quantDestination = dest
+            , quantTable = VS.fromListN 64 coeffs
+            }
+
+data JpgHuffmanTableSpec = JpgHuffmanTableSpec
+    { -- | 0 : DC, 1 : AC, stored on 4 bits
+      huffmanTableClass       :: !DctComponent
+      -- | Stored on 4 bits
+    , huffmanTableDest        :: !Word8
+
+    , huffSizes :: !(VU.Vector Word8)
+    , huffCodes :: !(V.Vector (VU.Vector Word8))
+    }
+    deriving (Eq, Show, Generic)
+instance NFData JpgHuffmanTableSpec
+
+instance SizeCalculable JpgHuffmanTableSpec where
+    calculateSize table = 1 + 16 + sum [fromIntegral e | e <- VU.toList $ huffSizes table]
+
+instance Binary JpgHuffmanTableSpec where
+    put table = do
+        let classVal = if huffmanTableClass table == DcComponent
+                          then 0 else 1
+        put4BitsOfEach classVal $ huffmanTableDest table
+        mapM_ put . VU.toList $ huffSizes table
+        forM_ [0 .. 15] $ \i ->
+            when (huffSizes table ! i /= 0)
+                 (let elements = VU.toList $ huffCodes table V.! i
+                  in mapM_ put elements)
+
+    get = do
+        (huffClass, huffDest) <- get4BitOfEach
+        sizes <- replicateM 16 getWord8
+        codes <- forM sizes $ \s ->
+            VU.replicateM (fromIntegral s) getWord8
+        return JpgHuffmanTableSpec
+            { huffmanTableClass =
+                if huffClass == 0 then DcComponent else AcComponent
+            , huffmanTableDest = huffDest
+            , huffSizes = VU.fromListN 16 sizes
+            , huffCodes = V.fromListN 16 codes
+            }
+
+instance Binary JpgImage where
+    put (JpgImage { jpgFrame = frames }) =
+        putWord8 0xFF >> putWord8 0xD8 >> mapM_ putFrame frames
+            >> putWord8 0xFF >> putWord8 0xD9
+
+    -- | Consider using `getJpgImage` instead for a non-semi-lazy implementation.
+    get = do
+        skipUntilFrames
+        frames <- parseFramesSemiLazy
+        -- let endOfImageMarker = 0xD9
+        {-checkMarker commonMarkerFirstByte endOfImageMarker-}
+        return JpgImage { jpgFrame = frames }
+
+-- | Like `get` from `instance Binary JpgImage`, but without the legacy
+-- semi-lazy implementation.
+getJpgImage :: Get JpgImage
+getJpgImage = do
+    skipUntilFrames
+    frames <- parseFrames
+    return JpgImage { jpgFrame = frames }
+
+skipUntilFrames :: Get ()
+skipUntilFrames = do
+    let startOfImageMarker = 0xD8
+    checkMarker commonMarkerFirstByte startOfImageMarker
+    eatUntilCode
+
+eatUntilCode :: Get ()
+eatUntilCode = do
+    code <- getWord8
+    unless (code == 0xFF) eatUntilCode
+
+takeCurrentFrame :: Get B.ByteString
+takeCurrentFrame = do
+    size <- getWord16be
+    getByteString (fromIntegral size - 2)
+
+putFrame :: JpgFrame -> Put
+putFrame (JpgAdobeAPP14 adobe) =
+    put (JpgAppSegment 14) >> putWord16be 14 >> put adobe
+putFrame (JpgJFIF jfif) =
+    put (JpgAppSegment 0) >> putWord16be (14+2) >> put jfif
+putFrame (JpgExif exif) = putExif exif
+putFrame (JpgAppFrame appCode str) =
+    put (JpgAppSegment appCode) >> putWord16be (fromIntegral $ B.length str) >> put str
+putFrame (JpgExtension appCode str) =
+    put (JpgExtensionSegment appCode) >> putWord16be (fromIntegral $ B.length str) >> put str
+putFrame (JpgQuantTable tables) =
+    put JpgQuantizationTable >> put (TableList tables)
+putFrame (JpgHuffmanTable tables) =
+    put JpgHuffmanTableMarker >> put (TableList $ map fst tables)
+putFrame (JpgIntervalRestart size) =
+    put JpgRestartInterval >> put (RestartInterval size)
+putFrame (JpgScanBlob hdr blob) =
+    put JpgStartOfScan >> put hdr >> putLazyByteString blob
+putFrame (JpgScans kind hdr) =
+    put kind >> put hdr
+
+--------------------------------------------------
+----            Serialization instances
+--------------------------------------------------
+commonMarkerFirstByte :: Word8
+commonMarkerFirstByte = 0xFF
+
+checkMarker :: Word8 -> Word8 -> Get ()
+checkMarker b1 b2 = do
+    rb1 <- getWord8
+    rb2 <- getWord8
+    when (rb1 /= b1 || rb2 /= b2)
+         (fail "Invalid marker used")
+
+-- | Simpler implementation of `parseECS` to allow an easier understanding
+-- of the logic, and to provide a comparison for correctness.
+parseECS_simple :: Get L.ByteString
+parseECS_simple = do
+    -- There's no efficient way in `binary` to parse byte-by-byte while assembling a
+    -- resulting ByteString (without using `.Internal` modules, which is what
+    --  `parseECS` does), so instead first compute the length of the content
+    -- byte-by-byte inside a `lookAhead` (not advancing the parser offset), and
+    -- then efficiently take that long a ByteString (advancing the parser offset).
+    --
+    -- This is still slow compared to `parseECS` because parser functions
+    -- (`getWord8`) are used repeatedly, instead of plain loops over ByteString contents.
+    -- The slowdown is ~2x on GHC 8.10.7 on an Intel Core i7-7500U.
+    n <- lookAhead getContentLength
+    getLazyByteString n
+  where
+    getContentLength :: Get ByteOffset
+    getContentLength = do
+        bytesReadBeforeContent <- bytesRead
+        let loop :: Word8 -> Get ByteOffset
+            loop !v = do
+                vNext <- getWord8
+                let isReset = 0xD0 <= vNext && vNext <= 0xD7
+                let vIsSegmentMarker = v == 0xFF && vNext /= 0 && not isReset
+                if not vIsSegmentMarker
+                    then loop vNext
+                    else do
+                        bytesReadAfterContentPlus2 <- bytesRead -- "plus 2" because we've also read the segment marker (0xFF and `vNext`)
+                        let !contentLength = (bytesReadAfterContentPlus2 - 2) - bytesReadBeforeContent
+                        return contentLength
+
+        v_first <- getWord8
+        loop v_first
+
+-- Replace by `Data.ByteString.dropEnd` once we require `bytestring >= 0.11.1.0`.
+bsDropEnd :: Int -> B.ByteString -> B.ByteString
+bsDropEnd n bs
+    | n <= 0    = bs
+    | n >= len  = B.empty
+    | otherwise = B.take (len - 1) bs
+  where
+    len = B.length bs
+{-# INLINE bsDropEnd #-}
+
+-- | Parses a Scan's ECS (Entropy-Coded Segment, the largest part of compressed image data)
+-- from the `Get` stream.
+--
+-- When this function is called, the parser's offset should be
+-- immediately behind the SOS tag.
+--
+-- As described on e.g. https://www.ccoderun.ca/programming/2017-01-31_jpeg/,
+--
+-- > To find the next segment after the SOS, you must keep reading until you
+-- > find a 0xFF bytes which is not immediately followed by 0x00 (see "byte stuffing")
+-- > [or a reset marker's byte: 0xD0 through 0xD7].
+-- > Normally, this will be the EOI segment that comes at the end of the file.
+--
+-- where the 0xFF is the next segment's marker.
+-- See https://github.com/corkami/formats/blob/master/image/jpeg.md#entropy-coded-segment
+-- for more details.
+--
+-- This function returns the ECS, not including the next segment's
+-- marker on its trailing end.
+parseECS :: Get L.ByteString
+parseECS = do
+    -- For a simpler but slower implementation of this function, see
+    -- `parseECS_simple`.
+
+    v_first <- getWord8
+    -- TODO: Compare with what `scan` from `binary-parsers` does.
+    --       Probably we cannot use it because it does not allow us to set the parser state
+    --       to be _before_ the segment marker which would be convenient to not have to
+    --       make a special case the function that calls this function.
+    --       But `scan` works on pointers into the bytestring chunks. Why, for performance?
+    --       I've asked on https://github.com/winterland1989/binary-parsers/issues/7
+    --       If that is for performance, we may want to replicate the same thing here.
+    --
+    --       An orthogonal idea is to use `Data.ByteString.elemIndex` to fast-forward
+    --       to the next 0xFF using `memchr`, but the `unsafe` call to `memchr` might
+    --       have too much overhead, since 0xFF bytes appear statistically every 256 bytes.
+    --       See https://stackoverflow.com/questions/14519905/how-much-does-it-cost-for-haskell-ffi-to-go-into-c-and-back
+
+    -- `withInputChunks` allows us to work on chunks of ByteStrings,
+    -- reducing the number of higher-overhead `Get` functions called.
+    -- It also allows to easily assemble the ByteString to return,
+    -- which may be cross-chunk.
+    -- `withInputChunks` terminates when we return a
+    --     Right (consumed :: ByteString, unconsumed :: ByteString)
+    -- from `consumeChunk`, setting the `Get` parser's offset to just before `unconsumed`.
+    -- Because the segment marker we seek may be the 2 bytes across chunk boundaries,
+    -- we need to keep a reference to the previous chunk (initialised as `B.empty`),
+    -- so that we can set `consumed` properly, because this function is supposed
+    -- to not consume the start of the segment marker (see code dropping the last
+    -- byte of the previous chunk below).
+    GetInternal.withInputChunks
+        (v_first, B.empty)
+        consumeChunk
+        (         L.fromChunks . (B.singleton v_first :)) -- `v_first` also belongs to the returned BS
+        (return . L.fromChunks . (B.singleton v_first :)) -- `v_first` also belongs to the returned BS
+  where
+    consumeChunk :: GetInternal.Consume (Word8, B.ByteString) -- which is: (Word8, B.ByteString) -> B.ByteString -> Either (Word8, B.ByteString) (B.ByteString, B.ByteString)
+    consumeChunk (!v_chunk_start, !prev_chunk) !chunk
+        -- If `withInputChunks` hands us an empty chunk (which `binary` probably
+        -- won't do, but since that's not documented, handle it anyway) then skip over it,
+        -- so that we always remember the last `prev_chunk` that actually has data in it,
+        -- since we `bsDropEnd 1 prev_chunk` in the `case` below.
+        | B.null chunk = Left (v_chunk_start, prev_chunk)
+        | otherwise = loop v_chunk_start 0
+          where
+            loop :: Word8 -> Int -> Either (Word8, B.ByteString) (B.ByteString, B.ByteString)
+            loop !v !offset_in_chunk
+                | offset_in_chunk >= B.length chunk = Left (v, chunk)
+                | otherwise =
+                    let !vNext = BU.unsafeIndex chunk offset_in_chunk -- bounds check is done above
+                        !isReset = 0xD0 <= vNext && vNext <= 0xD7
+                        !vIsSegmentMarker = v == 0xFF && vNext /= 0 && not isReset
+                    in
+                        if not vIsSegmentMarker
+                            then loop vNext (offset_in_chunk+1)
+                            else
+                                -- Set the parser state to _before_ the segment marker.
+                                -- The first case, where the segment marker's 2 bytes are exactly
+                                -- at the chunk boundary, requires us to allocate a new BS with
+                                -- `B.cons`; luckily this case should be rare.
+                                let (!consumed, !unconsumed) = case () of
+                                     () | offset_in_chunk == 0 -> (bsDropEnd 1 prev_chunk, v `B.cons` chunk) -- segment marker starts at `v`, which is the last byte of the previous chunk
+                                        | offset_in_chunk == 1 -> (B.empty, chunk) -- segment marker starts exactly at `chunk`
+                                        | otherwise            -> B.splitAt (offset_in_chunk - 1) chunk -- segment marker starts at `v`, which is 1 before `vNext` (which is at `offset_in_chunk`)
+                                in Right $! (consumed, unconsumed)
+
+
+
+parseAdobe14 :: B.ByteString -> Maybe JpgFrame
+parseAdobe14 str = case runGetStrict get str of
+    Left _err -> Nothing
+    Right app14 -> Just $! JpgAdobeAPP14 app14
+
+-- | Parse JFIF or JFXX information. Right now only JFIF.
+parseJF__ :: B.ByteString -> Maybe JpgFrame
+parseJF__ str = case runGetStrict get str of
+    Left _err -> Nothing
+    Right jfif -> Just $! JpgJFIF jfif
+
+parseExif :: B.ByteString -> Maybe JpgFrame
+parseExif str
+  | exifHeader `B.isPrefixOf` str =
+      let
+        tiff = B.drop (B.length exifHeader) str
+      in
+        case runGetStrict (getP tiff) tiff of
+            Left _err -> Nothing
+            Right (_hdr :: TiffHeader, []) -> Nothing
+            Right (_hdr :: TiffHeader, ifds : _) -> Just $! JpgExif ifds
+  | otherwise = Nothing
+  where
+    exifHeader = BC.pack "Exif\0\0"
+
+putExif :: [ImageFileDirectory] -> Put
+putExif ifds = putAll where
+  hdr = TiffHeader
+    { hdrEndianness = EndianBig
+    , hdrOffset = 8
+    }
+
+  ifdList = case partition (isInIFD0 . ifdIdentifier) ifds of
+    (ifd0, []) -> [ifd0]
+    (ifd0, ifdExif) -> [ifd0 <> pure exifOffsetIfd, ifdExif]
+
+  exifBlob = runPut $ do
+    putByteString $ BC.pack "Exif\0\0"
+    putP BC.empty (hdr, ifdList)
+
+  putAll = do
+    put (JpgAppSegment 1)
+    putWord16be . fromIntegral $ L.length exifBlob + 2
+    putLazyByteString exifBlob
+
+skipFrameMarker :: Get ()
+skipFrameMarker = do
+    word <- getWord8
+    when (word /= 0xFF) $ do
+        readedData <- bytesRead
+        fail $ "Invalid Frame marker (" ++ show word
+                ++ ", bytes read : " ++ show readedData ++ ")"
+
+-- | Parses a single frame.
+--
+-- Returns `Nothing` when we encounter a frame we want to skip.
+parseFrameOfKind :: JpgFrameKind -> Get (Maybe JpgFrame)
+parseFrameOfKind kind = do
+    case kind of
+        JpgEndOfImage -> return Nothing
+        JpgAppSegment 0 -> parseJF__ <$> takeCurrentFrame
+        JpgAppSegment 1 -> parseExif <$> takeCurrentFrame
+        JpgAppSegment 14 -> parseAdobe14 <$> takeCurrentFrame
+        JpgAppSegment c -> Just . JpgAppFrame c <$> takeCurrentFrame
+        JpgExtensionSegment c -> Just . JpgExtension c <$> takeCurrentFrame
+        JpgQuantizationTable ->
+            (\(TableList quants) -> Just $! JpgQuantTable quants) <$> get
+        JpgRestartInterval ->
+            (\(RestartInterval i) -> Just $! JpgIntervalRestart i) <$> get
+        JpgHuffmanTableMarker ->
+            (\(TableList huffTables) -> Just $!
+                    JpgHuffmanTable [(t, packHuffmanTree . buildPackedHuffmanTree $ huffCodes t) | t <- huffTables])
+                    <$> get
+        JpgStartOfScan -> do
+            scanHeader <- get
+            ecs <- parseECS
+            return $! Just $! JpgScanBlob scanHeader ecs
+        _ -> Just . JpgScans kind <$> get
+
+
+-- | Parse a list of `JpgFrame`s.
+--
+-- This function has various quirks; consider the below with great caution
+-- when using this function.
+--
+-- While @data JpgFrame = ... | JpgScanBlob !...` itself has strict fields,
+--
+-- This function is written in such a way that that it can construct
+-- the @[JpgFrame]@ "lazily" such that the expensive byte-by-byte traversal
+-- in `parseECS` to create a `JpgScanBlob` can be avoided if only
+-- list elements before that `JpgScanBlob` are evaluated.
+--
+-- That means the user can write code such as
+--
+-- > let mbFirstScan =
+-- >       case runGetOrFail (get @JPG.JpgImage) hugeImageByteString of -- (`get @JPG.JpgImage` uses `parseFramesSemiLazy`)
+-- >         Right (_restBs, _offset, res) ->
+-- >           find (\frame -> case frame of { JPG.JpgScans{} -> True; _ -> False }) (JPG.jpgFrame res)
+--
+-- with the guarantee that only the bytes before the ECS (large compressed image data)
+-- will be inspected, assuming that indeed there is at least 1 `JpgScan` in front
+-- of the `JpgScanBlob` that contains the ECS.
+--
+-- This guarantee can be useful to e.g. quickly read just the image
+-- dimensions (width, height) without traversing the large data.
+--
+-- Also note that this `Get` parser does not correctly maintain the parser byte offset
+-- (`Data.Binary.Get.bytesRead`), because as soon as a `JpgStartOfScan` is returned,
+-- it uses `Data.Binary.Get.getRemainingLazyBytes` to provide:
+--
+-- 1. the laziness described above, and
+-- 2. the ability to ignore any parser failure after the first successfully-parsed
+--    `JpgScanBlob` (it is debatable whether this behaviour is a desirable behaviour of this
+--    library, but it is historically so and existing exposed functions do not break
+--    this for backwards compatibility with existing uses of this library).
+--    This fact also means that even `parseNextFrameStrict` cannot maintain
+--    correct parser byte offsets.
+--
+-- Further note that if you are reading a huge JPEG image from disk strictly,
+-- this will already incur a full traversal (namely creation) of the `hugeImageByteString`.
+-- Thus, `parseNextFrameLazy` only provides any benefit if you:
+--
+-- - read the image from disk using lazy IO (not recommended!) such as via
+--   `Data.ByteString.Lazy.readFile`,
+-- - or do something similar, such as creating the `hugeImageByteString` via @mmap()@
+--
+-- This function is called "semi lazy" because only the first `JpgScanBlob` returned
+-- in the `[JpgFrame]` is returned lazily; frames of other types, or multiple
+-- `JpgScanBlob`s, are confusingly not dealt with lazily.
+--
+-- If as a caller you do not want to deal with any of these quirks,
+-- and use proper strict IO and/or via `Data.Binary.Get`'s incremental input interface:
+--
+-- - If you want the whole `[JpgFrame]`: use `parseFrames`.
+-- - If you want parsing to terminate early as in the example shown above,
+--   use in combination with just the right amount of `get :: Get JpgFrameKind`,
+--   `parseFrameOfKind`, and `skipFrameMarker`.
+parseFramesSemiLazy :: Get [JpgFrame]
+parseFramesSemiLazy = do
+    kind <- get
+    case kind of
+        -- The end-of-image case needs to be here because `_ ->` default case below
+        -- unconditionally uses `skipFrameMarker` which does not exist after `JpgEndOfImage`.
+        JpgEndOfImage -> pure []
+        JpgStartOfScan -> do
+            scanHeader <- get
+            remainingBytes <- getRemainingLazyBytes
+            -- It is after the above `getRemainingLazyBytes` that the `Get` parser lazily succeeds,
+            -- allowing consumers of `parseFramesSemiLazy` evaluate all `[JpgFrame]` list elements
+            -- until (excluding) the cons-cell around the `JpgScanBlob ...` we construct below.
+
+            return $ case runGet parseECS remainingBytes of
+                Left _ ->
+                    -- Construct invalid `JpgScanBlob` even when the compressed JPEG
+                    -- data is truncated or otherwise invalid, because that's what JuicyPixels's
+                    -- `parseFramesSemiLazy` function did in the past, for backwards compat.
+                    [JpgScanBlob scanHeader remainingBytes]
+                Right ecs ->
+                    JpgScanBlob scanHeader ecs
+                    :
+                    -- TODO Why `drop 1` instead of `runGet (skipFrameMarker *> parseFramesSemiLazy) remainingBytes` that would check that the dropped 1 Byte is really a frame marker?
+                    case runGet parseFramesSemiLazy (L.drop (L.length ecs + 1) remainingBytes) of
+                        -- After we've encountered the first scan blob containing encoded image data,
+                        -- we accept anything else after to fail parsing, ignoring that failure,
+                        -- end emitting no further frames.
+                        -- TODO: Explain why JuicyPixel chose to use this logic, insteaed of failing.
+                        Left _ -> []
+                        Right remainingFrames -> remainingFrames
+        _ -> do
+            mbFrame <- parseFrameOfKind kind
+            skipFrameMarker
+            remainingFrames <- parseFramesSemiLazy
+            return $ maybeToList mbFrame ++ remainingFrames
+
+-- | Parse a list of `JpgFrame`s.
+parseFrames :: Get [JpgFrame]
+parseFrames = do
+    kind <- get
+    case kind of
+        JpgEndOfImage -> pure []
+        _ -> do
+            mbFrame <- parseFrameOfKind kind
+            skipFrameMarker
+            remainingFrames <- parseFrames
+            return $ maybeToList mbFrame ++ remainingFrames
+
+-- | Parse a list of `JpgFrameKind`s with their corresponding offsets and lengths
+-- (not counting the segment and frame markers into the lengths).
+--
+-- Useful for debugging.
+parseFrameKinds :: Get [(JpgFrameKind, Int64, Int64)]
+parseFrameKinds = do
+    kindMarkerOffset :: Int64 <- bytesRead
+    kind <- get
+    case kind of
+        JpgEndOfImage -> pure [(JpgEndOfImage, kindMarkerOffset, 0)]
+        _ -> do
+            parserOffsetBefore <- bytesRead
+            _ <- parseFrameOfKind kind
+            parserOffsetAfter <- bytesRead
+            let !segmentLengthWithoutMarker = parserOffsetAfter - parserOffsetBefore
+            skipFrameMarker
+            remainingKinds <- parseFrameKinds
+            return $ (kind, kindMarkerOffset, segmentLengthWithoutMarker):remainingKinds
+
+-- | Parses forward, returning the first scan header encountered.
+--
+-- Should be used after `skipUntilFrames`.
+--
+-- Fails parsing when an SOS segment marker (`JpgStartOfScan`, resulting
+-- in `JpgScanBlob`) is encountered before an SOF segment marker (that
+-- results in `JpgScans` carrying the `JpgFrameHeader`).
+parseToFirstFrameHeader :: Get (Maybe JpgFrameHeader)
+parseToFirstFrameHeader = do
+    kind <- get
+    case kind of
+        JpgEndOfImage -> return Nothing
+        JpgStartOfScan -> fail "parseToFirstFrameHeader: Encountered SOS frame marker before frame header that tells its dimensions"
+        _ -> do
+            mbFrame <- parseFrameOfKind kind
+            case mbFrame of
+                Nothing -> continueSearching
+                Just frame -> case frame of
+                    JpgScans _ frameHeader -> return $ Just $! frameHeader
+                    _ -> continueSearching
+  where
+    continueSearching = do
+        skipFrameMarker
+        parseToFirstFrameHeader
+
+buildPackedHuffmanTree :: V.Vector (VU.Vector Word8) -> HuffmanTree
+buildPackedHuffmanTree = buildHuffmanTree . map VU.toList . V.toList
+
+secondStartOfFrameByteOfKind :: JpgFrameKind -> Word8
+secondStartOfFrameByteOfKind = aux
+  where
+    aux JpgBaselineDCTHuffman = 0xC0
+    aux JpgExtendedSequentialDCTHuffman = 0xC1
+    aux JpgProgressiveDCTHuffman = 0xC2
+    aux JpgLosslessHuffman = 0xC3
+    aux JpgDifferentialSequentialDCTHuffman = 0xC5
+    aux JpgDifferentialProgressiveDCTHuffman = 0xC6
+    aux JpgDifferentialLosslessHuffman = 0xC7
+    aux JpgExtendedSequentialArithmetic = 0xC9
+    aux JpgProgressiveDCTArithmetic = 0xCA
+    aux JpgLosslessArithmetic = 0xCB
+    aux JpgHuffmanTableMarker = 0xC4
+    aux JpgDifferentialSequentialDCTArithmetic = 0xCD
+    aux JpgDifferentialProgressiveDCTArithmetic = 0xCE
+    aux JpgDifferentialLosslessArithmetic = 0xCF
+    aux JpgEndOfImage = 0xD9
+    aux JpgQuantizationTable = 0xDB
+    aux JpgStartOfScan = 0xDA
+    aux JpgRestartInterval = 0xDD
+    aux (JpgRestartIntervalEnd v) = v
+    aux (JpgAppSegment a) = (a + 0xE0)
+    aux (JpgExtensionSegment a) = a
+
+data JpgImageKind = BaseLineDCT | ProgressiveDCT
+
+instance Binary JpgFrameKind where
+    put v = putWord8 0xFF >> put (secondStartOfFrameByteOfKind v)
+    get = do
+        -- no lookahead :(
+        {-word <- getWord8-}
+        word2 <- getWord8
+        case word2 of
+            0xC0 -> return JpgBaselineDCTHuffman
+            0xC1 -> return JpgExtendedSequentialDCTHuffman
+            0xC2 -> return JpgProgressiveDCTHuffman
+            0xC3 -> return JpgLosslessHuffman
+            0xC4 -> return JpgHuffmanTableMarker
+            0xC5 -> return JpgDifferentialSequentialDCTHuffman
+            0xC6 -> return JpgDifferentialProgressiveDCTHuffman
+            0xC7 -> return JpgDifferentialLosslessHuffman
+            0xC9 -> return JpgExtendedSequentialArithmetic
+            0xCA -> return JpgProgressiveDCTArithmetic
+            0xCB -> return JpgLosslessArithmetic
+            0xCD -> return JpgDifferentialSequentialDCTArithmetic
+            0xCE -> return JpgDifferentialProgressiveDCTArithmetic
+            0xCF -> return JpgDifferentialLosslessArithmetic
+            0xD9 -> return JpgEndOfImage
+            0xDA -> return JpgStartOfScan
+            0xDB -> return JpgQuantizationTable
+            0xDD -> return JpgRestartInterval
+            a | a >= 0xF0 -> return $! JpgExtensionSegment a
+              | a >= 0xE0 -> return $! JpgAppSegment (a - 0xE0)
+              | a >= 0xD0 && a <= 0xD7 -> return $! JpgRestartIntervalEnd a
+              | otherwise -> fail ("Invalid frame marker (" ++ show a ++ ")")
+
+put4BitsOfEach :: Word8 -> Word8 -> Put
+put4BitsOfEach a b = put $ (a `unsafeShiftL` 4) .|. b
+
+get4BitOfEach :: Get (Word8, Word8)
+get4BitOfEach = do
+    val <- get
+    return ((val `unsafeShiftR` 4) .&. 0xF, val .&. 0xF)
+
+newtype RestartInterval = RestartInterval Word16
+
+instance Binary RestartInterval where
+    put (RestartInterval i) = putWord16be 4 >> putWord16be i
+    get = do
+        size <- getWord16be
+        when (size /= 4) (fail "Invalid jpeg restart interval size")
+        RestartInterval <$> getWord16be
+
+instance Binary JpgComponent where
+    get = do
+        ident <- getWord8
+        (horiz, vert) <- get4BitOfEach
+        quantTableIndex <- getWord8
+        return JpgComponent
+            { componentIdentifier = ident
+            , horizontalSamplingFactor = horiz
+            , verticalSamplingFactor = vert
+            , quantizationTableDest = quantTableIndex
+            }
+    put v = do
+        put $ componentIdentifier v
+        put4BitsOfEach (horizontalSamplingFactor v) $ verticalSamplingFactor v
+        put $ quantizationTableDest v
+
+instance Binary JpgFrameHeader where
+    get = do
+        beginOffset <- fromIntegral <$> bytesRead
+        frmHLength <- getWord16be
+        samplePrec <- getWord8
+        h <- getWord16be
+        w <- getWord16be
+        compCount <- getWord8
+        components <- replicateM (fromIntegral compCount) get
+        endOffset <- fromIntegral <$> bytesRead
+        when (beginOffset - endOffset < fromIntegral frmHLength)
+             (skip $ fromIntegral frmHLength - (endOffset - beginOffset))
+        return JpgFrameHeader
+            { jpgFrameHeaderLength = frmHLength
+            , jpgSamplePrecision = samplePrec
+            , jpgHeight = h
+            , jpgWidth = w
+            , jpgImageComponentCount = compCount
+            , jpgComponents = components
+            }
+
+    put v = do
+        putWord16be $ jpgFrameHeaderLength v
+        putWord8    $ jpgSamplePrecision v
+        putWord16be $ jpgHeight v
+        putWord16be $ jpgWidth v
+        putWord8    $ jpgImageComponentCount v
+        mapM_ put   $ jpgComponents v
+
+instance Binary JpgScanSpecification where
+    put v = do
+        put $ componentSelector v
+        put4BitsOfEach (dcEntropyCodingTable v) $ acEntropyCodingTable v
+
+    get = do
+        compSel <- get
+        (dc, ac) <- get4BitOfEach
+        return JpgScanSpecification {
+            componentSelector = compSel
+          , dcEntropyCodingTable = dc
+          , acEntropyCodingTable = ac
+          }
+
+instance Binary JpgScanHeader where
+    get = do
+        thisScanLength <- getWord16be
+        compCount <- getWord8
+        comp <- replicateM (fromIntegral compCount) get
+        specBeg <- get
+        specEnd <- get
+        (approxHigh, approxLow) <- get4BitOfEach
+
+        return JpgScanHeader {
+            scanLength = thisScanLength,
+            scanComponentCount = compCount,
+            scans = comp,
+            spectralSelection = (specBeg, specEnd),
+            successiveApproxHigh = approxHigh,
+            successiveApproxLow = approxLow
+        }
+
+    put v = do
+        putWord16be $ scanLength v
+        putWord8 $ scanComponentCount v
+        mapM_ put $ scans v
+        putWord8 . fst $ spectralSelection v
+        putWord8 . snd $ spectralSelection v
+        put4BitsOfEach (successiveApproxHigh v) $ successiveApproxLow v
+
+{-# INLINE createEmptyMutableMacroBlock #-}
+-- | Create a new macroblock with the good array size
+createEmptyMutableMacroBlock :: (Storable a, Num a) => ST s (MutableMacroBlock s a)
+createEmptyMutableMacroBlock = M.replicate 64 0
+
+printMacroBlock :: (Storable a, PrintfArg a)
+                => MutableMacroBlock s a -> ST s String
+printMacroBlock block = pLn 0
+    where pLn 64 = return "===============================\n"
+          pLn i = do
+              v <- block `M.unsafeRead` i
+              vn <- pLn (i+1)
+              return $ printf (if i `mod` 8 == 0 then "\n%5d " else "%5d ") v ++ vn
+
+printPureMacroBlock :: (Storable a, PrintfArg a) => MacroBlock a -> String
+printPureMacroBlock block = pLn 0
+    where pLn 64 = "===============================\n"
+          pLn i = str ++ pLn (i + 1)
+            where str | i `mod` 8 == 0 = printf "\n%5d " v
+                      | otherwise = printf "%5d" v
+                  v = block VS.! i
+
+
+{-# INLINE dctBlockSize #-}
+dctBlockSize :: Num a => a
+dctBlockSize = 8
− src/Codec/Picture/Jpg/Metadata.hs
@@ -1,41 +0,0 @@-{-# LANGUAGE CPP #-}-module Codec.Picture.Jpg.Metadata ( extractMetadatas, encodeMetadatas ) where--#if !MIN_VERSION_base(4,8,0)-import Control.Applicative( pure )-import Data.Monoid( mempty )-import Data.Word( Word )-#endif--import Data.Word( Word16 )-import Data.Maybe( fromMaybe )-import qualified Codec.Picture.Metadata as Met-import Codec.Picture.Metadata( Metadatas )-import Codec.Picture.Jpg.Types--scalerOfUnit :: JFifUnit -> Met.Keys Word -> Word16 -> Metadatas -> Metadatas-scalerOfUnit unit k v = case unit of-  JFifUnitUnknown -> id-  JFifPixelsPerInch -> Met.insert k (fromIntegral v)-  JFifPixelsPerCentimeter ->-    Met.insert k (Met.dotsPerCentiMeterToDotPerInch $ fromIntegral v)--extractMetadatas :: JpgJFIFApp0 -> Metadatas-extractMetadatas jfif = -    inserter Met.DpiX (_jfifDpiX jfif)-        $ inserter Met.DpiY (_jfifDpiY jfif) mempty-  where-    inserter = scalerOfUnit $ _jfifUnit jfif---encodeMetadatas :: Metadatas -> [JpgFrame]-encodeMetadatas metas = fromMaybe [] $ do-  dpiX <- Met.lookup Met.DpiX metas-  dpiY <- Met.lookup Met.DpiY metas-  pure . pure . JpgJFIF $ JpgJFIFApp0-    { _jfifUnit      = JFifPixelsPerInch-    , _jfifDpiX      = fromIntegral dpiX-    , _jfifDpiY      = fromIntegral dpiY-    , _jfifThumbnail = Nothing-    }-
− src/Codec/Picture/Jpg/Progressive.hs
@@ -1,332 +0,0 @@-{-# LANGUAGE TupleSections #-}
-{-# LANGUAGE TypeSynonymInstances #-}
-{-# LANGUAGE FlexibleInstances #-}
-{-# LANGUAGE ScopedTypeVariables #-}
-{-# LANGUAGE CPP #-}
-module Codec.Picture.Jpg.Progressive
-    ( JpgUnpackerParameter( .. )
-    , progressiveUnpack
-    ) where
-
-#if !MIN_VERSION_base(4,8,0)
-import Control.Applicative( pure, (<$>) )
-#endif
-
-import Control.Monad( when, unless, forM_ )
-import Control.Monad.ST( ST )
-import Control.Monad.Trans( lift )
-import Data.Bits( (.&.), (.|.), unsafeShiftL )
-import Data.Int( Int16, Int32 )
-import qualified Data.ByteString as B
-import qualified Data.ByteString.Lazy as L
-import qualified Data.Vector as V
-import qualified Data.Vector.Storable as VS
-import Data.Vector( (!) )
-import qualified Data.Vector.Mutable as M
-import qualified Data.Vector.Storable.Mutable as MS
-
-import Codec.Picture.Types
-import Codec.Picture.BitWriter
-import Codec.Picture.Jpg.Common
-import Codec.Picture.Jpg.Types
-import Codec.Picture.Jpg.DefaultTable
-
-createMcuLineIndices :: JpgComponent -> Int -> Int -> V.Vector (VS.Vector Int)
-createMcuLineIndices param imgWidth mcuWidth =
- V.fromList $ VS.fromList <$> [indexSolo, indexMulti]
-  where compW = fromIntegral $ horizontalSamplingFactor param
-        compH = fromIntegral $ verticalSamplingFactor param
-        imageBlockSize = toBlockSize imgWidth
-
-        -- if the displayed MCU block is only displayed in half (like with
-        -- width 500 then we loose one macroblock of the MCU at the end of
-        -- the line. Previous implementation which naively used full mcu
-        -- was wrong. Only taking into account visible macroblocks
-        indexSolo = [base + x
-            | y <- [0 .. compH - 1]
-            , let base = y * mcuWidth * compW
-            , x <- [0 .. imageBlockSize - 1]]
-
-        indexMulti =
-            [(mcu + y * mcuWidth) * compW + x
-                | mcu <- [0 .. mcuWidth - 1]
-                , y <- [0 .. compH - 1]
-                , x <- [0 .. compW - 1] ]
-
-decodeFirstDC :: JpgUnpackerParameter
-              -> MS.STVector s Int16
-              -> MutableMacroBlock s Int16
-              -> Int32
-              -> BoolReader s Int32
-decodeFirstDC params dcCoeffs block eobrun = unpack >> pure eobrun
-  where unpack = do
-          (dcDeltaCoefficient) <- dcCoefficientDecode $ dcHuffmanTree params
-          previousDc <- lift $ dcCoeffs `MS.unsafeRead` componentIndex params
-          let neoDcCoefficient = previousDc + dcDeltaCoefficient
-              approxLow = fst $ successiveApprox params
-              scaledDc = neoDcCoefficient `unsafeShiftL` approxLow
-          lift $ (block `MS.unsafeWrite` 0) scaledDc 
-          lift $ (dcCoeffs `MS.unsafeWrite` componentIndex params) neoDcCoefficient
-
-decodeRefineDc :: JpgUnpackerParameter
-               -> a
-               -> MutableMacroBlock s Int16
-               -> Int32
-               -> BoolReader s Int32
-decodeRefineDc params _ block eobrun = unpack >> pure eobrun
-  where approxLow = fst $ successiveApprox params
-        plusOne = 1 `unsafeShiftL` approxLow
-        unpack = do
-            bit <- getNextBitJpg
-            when bit . lift $ do
-                v <- block `MS.unsafeRead` 0
-                (block `MS.unsafeWrite` 0) $ v .|. plusOne
-
-decodeFirstAc :: JpgUnpackerParameter
-              -> a
-              -> MutableMacroBlock s Int16
-              -> Int32
-              -> BoolReader s Int32
-decodeFirstAc _params _ _block eobrun | eobrun > 0 = pure $ eobrun - 1
-decodeFirstAc params _ block _ = unpack startIndex
-  where (startIndex, maxIndex) = coefficientRange params
-        (low, _) = successiveApprox params
-        unpack n | n > maxIndex = pure 0
-        unpack n = do
-            rrrrssss <- decodeRrrrSsss $ acHuffmanTree params
-            case rrrrssss of
-                (0xF, 0) -> unpack $ n + 16
-                (  0, 0) -> return 0
-                (  r, 0) -> eobrun <$> unpackInt r
-                    where eobrun lowBits = (1 `unsafeShiftL` r) - 1 + lowBits
-                (  r, s) -> do
-                    let n' = n + r
-                    val <- (`unsafeShiftL` low) <$> decodeInt s
-                    lift . (block `MS.unsafeWrite` n') $ fromIntegral val
-                    unpack $ n' + 1
-
-decodeRefineAc :: forall a s. JpgUnpackerParameter
-               -> a
-               -> MutableMacroBlock s Int16
-               -> Int32
-               -> BoolReader s Int32
-decodeRefineAc params _ block eobrun
-        | eobrun == 0 = unpack startIndex
-        | otherwise   = performEobRun startIndex >> return (eobrun - 1)
-  where (startIndex, maxIndex) = coefficientRange params
-        (low, _) = successiveApprox params
-        plusOne = 1 `unsafeShiftL` low
-        minusOne = (-1) `unsafeShiftL` low
-
-        getBitVal = do
-            v <- getNextBitJpg
-            pure $ if v then plusOne else minusOne
-
-        performEobRun idx | idx > maxIndex = pure ()
-        performEobRun idx = do
-          coeff <- lift $ block `MS.unsafeRead` idx
-          if coeff /= 0 then do
-            bit <- getNextBitJpg
-            case (bit, (coeff .&. plusOne) == 0) of
-               (False, _)    -> performEobRun $ idx + 1
-               (True, False) -> performEobRun $ idx + 1
-               (True, True) -> do
-                   let newVal | coeff >= 0 = coeff + plusOne
-                              | otherwise = coeff + minusOne
-                   lift $ (block `MS.unsafeWrite` idx) newVal
-                   performEobRun $ idx + 1
-          else
-            performEobRun $ idx + 1
-
-        unpack idx | idx > maxIndex = pure 0
-        unpack idx = do
-            rrrrssss <- decodeRrrrSsss $ acHuffmanTree params
-            case rrrrssss of
-              (0xF, 0) -> do
-                idx' <- updateCoeffs 0xF idx
-                unpack $ idx' + 1
-
-              (  r, 0) -> do
-                  lowBits <- unpackInt r
-                  let newEobRun = (1 `unsafeShiftL` r) + lowBits - 1
-                  performEobRun idx
-                  pure newEobRun
-
-              (  r, _) -> do
-                  val <- getBitVal
-                  idx' <- updateCoeffs (fromIntegral r) idx
-                  when (idx' <= maxIndex) $
-                       lift $ (block `MS.unsafeWrite` idx') val
-                  unpack $ idx' + 1
-
-        updateCoeffs :: Int -> Int -> BoolReader s Int
-        updateCoeffs r idx
-            | r   < 0        = pure $ idx - 1
-            | idx > maxIndex = pure idx
-        updateCoeffs r idx = do
-          coeff <- lift $ block `MS.unsafeRead` idx
-          if coeff /= 0 then do
-            bit <- getNextBitJpg
-            when (bit && coeff .&. plusOne == 0) $ do
-              let writeCoeff | coeff >= 0 = coeff + plusOne
-                             | otherwise = coeff + minusOne
-              lift $ (block `MS.unsafeWrite` idx) writeCoeff
-            updateCoeffs r $ idx + 1
-          else
-            updateCoeffs (r - 1) $ idx + 1
-
-type Unpacker s =
-    JpgUnpackerParameter -> MS.STVector s Int16 -> MutableMacroBlock s Int16 -> Int32
-        -> BoolReader s Int32
-
-
-prepareUnpacker :: [([(JpgUnpackerParameter, a)], L.ByteString)]
-                -> ST s ( V.Vector (V.Vector (JpgUnpackerParameter, Unpacker s))
-                        , M.STVector s BoolState)
-prepareUnpacker lst = do
-    let boolStates = V.fromList $ map snd infos
-    vec <- V.unsafeThaw boolStates
-    return (V.fromList $ map fst infos, vec)
-  where infos = map prepare lst
-        prepare ([], _) = error "progressiveUnpack, no component"
-        prepare (whole@((param, _) : _) , byteString) =
-         (V.fromList $ map (\(p,_) -> (p, unpacker)) whole, boolReader)
-           where unpacker = selection (successiveApprox param) (coefficientRange param)
-                 boolReader = initBoolStateJpg . B.concat $ L.toChunks byteString
-
-                 selection (_, 0) (0, _) = decodeFirstDC
-                 selection (_, 0) _      = decodeFirstAc
-                 selection _      (0, _) = decodeRefineDc
-                 selection _      _      = decodeRefineAc
-
-data ComponentData s = ComponentData
-  { componentIndices    :: V.Vector (VS.Vector Int)
-  , componentBlocks     :: V.Vector (MutableMacroBlock s Int16)
-  , componentId         :: !Int
-  , componentBlockCount :: !Int
-  }
-
--- | Iteration from 0 to n in monadic context, without data
--- keeping.
-lineMap :: (Monad m) => Int -> (Int -> m ()) -> m ()
-{-# INLINE lineMap #-}
-lineMap count f = go 0
-  where go n | n >= count = return ()
-        go n = f n >> go (n + 1)
-
-progressiveUnpack :: (Int, Int)
-                  -> JpgFrameHeader
-                  -> V.Vector (MacroBlock Int16)
-                  -> [([(JpgUnpackerParameter, a)], L.ByteString)]
-                  -> ST s (MutableImage s PixelYCbCr8)
-progressiveUnpack (maxiW, maxiH) frame quants lst = do
-    (unpackers, readers) <- prepareUnpacker lst
-    allBlocks <- mapM allocateWorkingBlocks . zip [0..] $ jpgComponents frame
-                    :: ST s [ComponentData s]
-    let scanCount = length lst
-        restartIntervalValue = case lst of
-                ((p,_):_,_): _ -> restartInterval p
-                _ -> -1
-    dcCoeffs <- MS.replicate imgComponentCount 0
-    eobRuns <- MS.replicate (length lst) 0
-    workBlock <- createEmptyMutableMacroBlock
-    writeIndices <- MS.replicate imgComponentCount (0 :: Int)
-    restartIntervals <- MS.replicate scanCount restartIntervalValue
-    let elementCount = imgWidth * imgHeight * fromIntegral imgComponentCount
-    img <- MutableImage imgWidth imgHeight <$> MS.replicate elementCount 128
-
-    let processRestartInterval =
-          forM_ [0 .. scanCount - 1] $ \ix -> do
-            v <- restartIntervals `MS.read` ix
-            if v == 0 then do
-              -- reset DC prediction
-              when (ix == 0) (MS.set dcCoeffs 0)
-              reader <- readers `M.read` ix
-              (_, updated) <- runBoolReaderWith reader $
-                  byteAlignJpg >> decodeRestartInterval
-              (readers `M.write` ix) updated 
-              (eobRuns `MS.unsafeWrite` ix) 0
-              (restartIntervals `MS.unsafeWrite` ix) $ restartIntervalValue - 1
-            else
-              (restartIntervals `MS.unsafeWrite` ix) $ v - 1
-
-
-    lineMap imageMcuHeight $ \mmY -> do
-      -- Reset all blocks to 0
-      forM_ allBlocks $ V.mapM_ (`MS.set` 0) .  componentBlocks
-      MS.set writeIndices 0
-
-      lineMap imageMcuWidth $ \_mmx -> do
-        processRestartInterval 
-        V.forM_ unpackers $ V.mapM_ $ \(unpackParam, unpacker) -> do
-            boolState <- readers `M.read` readerIndex unpackParam
-            eobrun <- eobRuns `MS.read` readerIndex unpackParam
-            let componentNumber = componentIndex unpackParam
-            writeIndex <- writeIndices `MS.read` componentNumber
-            let componentData = allBlocks !! componentNumber
-                -- We get back the correct block indices for the number of component
-                -- in the current scope (precalculated)
-                indexVector =
-                    componentIndices componentData ! indiceVector unpackParam
-                maxIndexLength = VS.length indexVector
-            unless (writeIndex + blockIndex unpackParam >= maxIndexLength) $ do
-               let realIndex = indexVector VS.! (writeIndex + blockIndex unpackParam)
-                   writeBlock = componentBlocks componentData ! realIndex
-               (eobrun', state) <-
-                   runBoolReaderWith boolState $
-                       unpacker unpackParam dcCoeffs writeBlock eobrun
-
-               (readers `M.write` readerIndex unpackParam) state
-               (eobRuns `MS.write` readerIndex unpackParam) eobrun'
-
-        -- Update the write indices
-        forM_ allBlocks $ \comp -> do
-          writeIndex <- writeIndices `MS.read` componentId comp
-          let newIndex = writeIndex + componentBlockCount comp
-          (writeIndices `MS.write` componentId comp) newIndex
-
-      forM_ allBlocks $ \compData -> do
-        let compBlocks = componentBlocks compData
-            cId = componentId compData
-            comp = jpgComponents frame !! cId
-            quantId =
-                fromIntegral $ quantizationTableDest comp
-            table = quants ! min 3 quantId
-            compW = fromIntegral $ horizontalSamplingFactor comp
-            compH = fromIntegral $ verticalSamplingFactor comp
-            cw8 = maxiW - fromIntegral (horizontalSamplingFactor comp) + 1
-            ch8 = maxiH - fromIntegral (verticalSamplingFactor comp) + 1
-
-        rasterMap (imageMcuWidth * compW) compH $ \rx y -> do
-            let ry = mmY * maxiH + y
-                block = compBlocks ! (y * imageMcuWidth * compW + rx)
-            transformed <- decodeMacroBlock table workBlock block
-            unpackMacroBlock imgComponentCount
-                    cw8 ch8 cId (rx * cw8) ry
-                    img transformed
-
-    return img
-
-  where imgComponentCount = length $ jpgComponents frame
-
-        imgWidth = fromIntegral $ jpgWidth frame
-        imgHeight = fromIntegral $ jpgHeight frame
-
-        imageBlockWidth = toBlockSize imgWidth
-        imageBlockHeight = toBlockSize imgHeight
-
-        imageMcuWidth =  (imageBlockWidth + (maxiW - 1)) `div` maxiW
-        imageMcuHeight = (imageBlockHeight + (maxiH - 1)) `div` maxiH
-
-        allocateWorkingBlocks (ix, comp) = do
-            let blockCount = hSample * vSample * imageMcuWidth * 2
-            blocks <- V.replicateM blockCount createEmptyMutableMacroBlock
-            return ComponentData 
-                { componentBlocks = blocks
-                , componentIndices = createMcuLineIndices comp imgWidth imageMcuWidth
-                , componentBlockCount = hSample * vSample
-                , componentId = ix
-                }
-            where hSample = fromIntegral $ horizontalSamplingFactor comp
-                  vSample = fromIntegral $ verticalSamplingFactor comp
-
− src/Codec/Picture/Jpg/Types.hs
@@ -1,753 +0,0 @@-{-# LANGUAGE ScopedTypeVariables #-}
-{-# LANGUAGE TypeFamilies #-}
-{-# LANGUAGE CPP #-}
-module Codec.Picture.Jpg.Types( MutableMacroBlock
-                              , createEmptyMutableMacroBlock
-                              , printMacroBlock
-                              , printPureMacroBlock
-                              , DcCoefficient
-                              , JpgImage( .. )
-                              , JpgComponent( .. )
-                              , JpgFrameHeader( .. )
-                              , JpgFrame( .. )
-                              , JpgFrameKind( .. )
-                              , JpgScanHeader( .. )
-                              , JpgQuantTableSpec( .. )
-                              , JpgHuffmanTableSpec( .. )
-                              , JpgImageKind( .. )
-                              , JpgScanSpecification( .. )
-                              , JpgColorSpace( .. )
-                              , AdobeTransform( .. )
-                              , JpgAdobeApp14( .. )
-                              , JpgJFIFApp0( .. )
-                              , JFifUnit( .. )
-                              , calculateSize
-                              , dctBlockSize
-                              ) where
-
-
-#if !MIN_VERSION_base(4,8,0)
-import Control.Applicative( pure, (<*>), (<$>) )
-#endif
-
-import Control.Monad( when, replicateM, forM, forM_, unless )
-import Control.Monad.ST( ST )
-import Data.Bits( (.|.), (.&.), unsafeShiftL, unsafeShiftR )
-import Data.List( partition )
-import Data.Monoid( (<>) )
-import Foreign.Storable ( Storable )
-import Data.Vector.Unboxed( (!) )
-import qualified Data.Vector as V
-import qualified Data.Vector.Unboxed as VU
-import qualified Data.Vector.Storable as VS
-import qualified Data.Vector.Storable.Mutable as M
-import qualified Data.ByteString as B
-import qualified Data.ByteString.Char8 as BC
-import qualified Data.ByteString.Lazy as L
-
-import Data.Int( Int16 )
-import Data.Word(Word8, Word16 )
-import Data.Binary( Binary(..) )
-
-import Data.Binary.Get( Get
-                      , getWord8
-                      , getWord16be
-                      , getByteString
-                      , skip
-                      , bytesRead
-                      )
-
-import Data.Binary.Put( Put
-                      , putWord8
-                      , putWord16be
-                      , putLazyByteString
-                      , putByteString
-                      , runPut
-                      )
-
-import Codec.Picture.InternalHelper
-import Codec.Picture.Jpg.DefaultTable
-import Codec.Picture.Tiff.Types
-import Codec.Picture.Tiff.Metadata( exifOffsetIfd )
-import Codec.Picture.Metadata.Exif
-
-{-import Debug.Trace-}
-import Text.Printf
-
--- | Type only used to make clear what kind of integer we are carrying
--- Might be transformed into newtype in the future
-type DcCoefficient = Int16
-
--- | Macroblock that can be transformed.
-type MutableMacroBlock s a = M.STVector s a
-
-data JpgFrameKind =
-      JpgBaselineDCTHuffman
-    | JpgExtendedSequentialDCTHuffman
-    | JpgProgressiveDCTHuffman
-    | JpgLosslessHuffman
-    | JpgDifferentialSequentialDCTHuffman
-    | JpgDifferentialProgressiveDCTHuffman
-    | JpgDifferentialLosslessHuffman
-    | JpgExtendedSequentialArithmetic
-    | JpgProgressiveDCTArithmetic
-    | JpgLosslessArithmetic
-    | JpgDifferentialSequentialDCTArithmetic
-    | JpgDifferentialProgressiveDCTArithmetic
-    | JpgDifferentialLosslessArithmetic
-    | JpgQuantizationTable
-    | JpgHuffmanTableMarker
-    | JpgStartOfScan
-    | JpgEndOfImage
-    | JpgAppSegment Word8
-    | JpgExtensionSegment Word8
-
-    | JpgRestartInterval
-    | JpgRestartIntervalEnd Word8
-    deriving (Eq, Show)
-
-data JpgFrame =
-      JpgAppFrame        !Word8 B.ByteString
-    | JpgAdobeAPP14      !JpgAdobeApp14
-    | JpgJFIF            !JpgJFIFApp0
-    | JpgExif            ![ImageFileDirectory]
-    | JpgExtension       !Word8 B.ByteString
-    | JpgQuantTable      ![JpgQuantTableSpec]
-    | JpgHuffmanTable    ![(JpgHuffmanTableSpec, HuffmanPackedTree)]
-    | JpgScanBlob        !JpgScanHeader !L.ByteString
-    | JpgScans           !JpgFrameKind !JpgFrameHeader
-    | JpgIntervalRestart !Word16
-    deriving Show
-
-data JpgColorSpace
-  = JpgColorSpaceYCbCr
-  | JpgColorSpaceYCC
-  | JpgColorSpaceY
-  | JpgColorSpaceYA
-  | JpgColorSpaceYCCA
-  | JpgColorSpaceYCCK
-  | JpgColorSpaceCMYK
-  | JpgColorSpaceRGB
-  | JpgColorSpaceRGBA
-  deriving Show
-
-data AdobeTransform
-  = AdobeUnknown    -- ^ Value 0
-  | AdobeYCbCr      -- ^ value 1
-  | AdobeYCck       -- ^ value 2
-  deriving Show
-
-data JpgAdobeApp14 = JpgAdobeApp14
-  { _adobeDctVersion :: !Word16
-  , _adobeFlag0      :: !Word16
-  , _adobeFlag1      :: !Word16
-  , _adobeTransform  :: !AdobeTransform
-  }
-  deriving Show
-
--- | Size: 1
-data JFifUnit
-  = JFifUnitUnknown   -- ^ 0
-  | JFifPixelsPerInch -- ^ 1
-  | JFifPixelsPerCentimeter -- ^ 2
-  deriving Show
-
-instance Binary JFifUnit where
-  put v = putWord8 $ case v of
-    JFifUnitUnknown -> 0
-    JFifPixelsPerInch -> 1
-    JFifPixelsPerCentimeter -> 2
-  get = do
-    v <- getWord8
-    pure $ case v of
-      0 -> JFifUnitUnknown
-      1 -> JFifPixelsPerInch
-      2 -> JFifPixelsPerCentimeter
-      _ -> JFifUnitUnknown
-
-data JpgJFIFApp0 = JpgJFIFApp0
-  { _jfifUnit      :: !JFifUnit
-  , _jfifDpiX      :: !Word16
-  , _jfifDpiY      :: !Word16
-  , _jfifThumbnail :: !(Maybe {- (Image PixelRGB8) -} Int)
-  }
-  deriving Show
-
-instance Binary JpgJFIFApp0 where
-  get = do
-    sig <- getByteString 5
-    when (sig /= BC.pack "JFIF\0") $
-        fail "Invalid JFIF signature"
-    major <- getWord8
-    minor <- getWord8
-    when (major /= 1 && minor > 2) $
-        fail "Unrecognize JFIF version"
-    unit <- get
-    dpiX <- getWord16be
-    dpiY <- getWord16be
-    w <- getWord8
-    h <- getWord8
-    let pxCount = 3 * w * h
-    img <- case pxCount of
-      0 -> return Nothing
-      _ -> return Nothing
-    return $ JpgJFIFApp0
-        { _jfifUnit      = unit
-        , _jfifDpiX      = dpiX
-        , _jfifDpiY      = dpiY
-        , _jfifThumbnail = img
-        }
-
-
-  put jfif = do
-    putByteString $ BC.pack "JFIF\0" -- 5
-    putWord8 1                       -- 1 6
-    putWord8 2                       -- 1 7
-    put $ _jfifUnit jfif             -- 1 8
-    putWord16be $ _jfifDpiX jfif     -- 2 10
-    putWord16be $ _jfifDpiY jfif     -- 2 12
-    putWord8 0                       -- 1 13
-    putWord8 0                       -- 1 14
-
-{-Thumbnail width (tw) 	1 	Horizontal size of embedded JFIF thumbnail in pixels-}
-{-Thumbnail height (th) 	1 	Vertical size of embedded JFIF thumbnail in pixels-}
-{-Thumbnail data 	3 × tw × th 	Uncompressed 24 bit RGB raster thumbnail-}
-
-instance Binary AdobeTransform where
-  put v = case v of
-    AdobeUnknown -> putWord8 0
-    AdobeYCbCr -> putWord8 1
-    AdobeYCck -> putWord8 2
-
-  get = do
-    v <- getWord8
-    pure $ case v of
-      0 -> AdobeUnknown
-      1 -> AdobeYCbCr
-      2 -> AdobeYCck
-      _ -> AdobeUnknown
-
-instance Binary JpgAdobeApp14 where
-  get = do
-    let sig = BC.pack "Adobe"
-    fileSig <- getByteString 5
-    when (fileSig /= sig) $
-       fail "Invalid Adobe APP14 marker"
-    version <- getWord16be
-    when (version /= 100) $
-       fail $ "Invalid Adobe APP14 version " ++ show version
-    JpgAdobeApp14 version
-                  <$> getWord16be
-                  <*> getWord16be <*> get
-
-  put (JpgAdobeApp14 v f0 f1 t) = do
-    putByteString $ BC.pack "Adobe"
-    putWord16be v
-    putWord16be f0
-    putWord16be f1
-    put t
-
-
-data JpgFrameHeader = JpgFrameHeader
-    { jpgFrameHeaderLength   :: !Word16
-    , jpgSamplePrecision     :: !Word8
-    , jpgHeight              :: !Word16
-    , jpgWidth               :: !Word16
-    , jpgImageComponentCount :: !Word8
-    , jpgComponents          :: ![JpgComponent]
-    }
-    deriving Show
-
-
-instance SizeCalculable JpgFrameHeader where
-    calculateSize hdr = 2 + 1 + 2 + 2 + 1
-                      + sum [calculateSize c | c <- jpgComponents hdr]
-
-data JpgComponent = JpgComponent
-    { componentIdentifier       :: !Word8
-      -- | Stored with 4 bits
-    , horizontalSamplingFactor  :: !Word8
-      -- | Stored with 4 bits
-    , verticalSamplingFactor    :: !Word8
-    , quantizationTableDest     :: !Word8
-    }
-    deriving Show
-
-instance SizeCalculable JpgComponent where
-    calculateSize _ = 3
-
-data JpgImage = JpgImage { jpgFrame :: [JpgFrame] }
-    deriving Show
-
-data JpgScanSpecification = JpgScanSpecification
-    { componentSelector :: !Word8
-      -- | Encoded as 4 bits
-    , dcEntropyCodingTable :: !Word8
-      -- | Encoded as 4 bits
-    , acEntropyCodingTable :: !Word8
-
-    }
-    deriving Show
-
-instance SizeCalculable JpgScanSpecification where
-    calculateSize _ = 2
-
-data JpgScanHeader = JpgScanHeader
-    { scanLength :: !Word16
-    , scanComponentCount :: !Word8
-    , scans :: [JpgScanSpecification]
-
-      -- | (begin, end)
-    , spectralSelection    :: (Word8, Word8)
-
-      -- | Encoded as 4 bits
-    , successiveApproxHigh :: !Word8
-
-      -- | Encoded as 4 bits
-    , successiveApproxLow :: !Word8
-    }
-    deriving Show
-
-instance SizeCalculable JpgScanHeader where
-    calculateSize hdr = 2 + 1
-                      + sum [calculateSize c | c <- scans hdr]
-                      + 2
-                      + 1
-
-data JpgQuantTableSpec = JpgQuantTableSpec
-    { -- | Stored on 4 bits
-      quantPrecision     :: !Word8
-
-      -- | Stored on 4 bits
-    , quantDestination   :: !Word8
-
-    , quantTable         :: MacroBlock Int16
-    }
-    deriving Show
-
-class SizeCalculable a where
-    calculateSize :: a -> Int
-
--- | Type introduced only to avoid some typeclass overlapping
--- problem
-newtype TableList a = TableList [a]
-
-instance (SizeCalculable a, Binary a) => Binary (TableList a) where
-    put (TableList lst) = do
-        putWord16be . fromIntegral $ sum [calculateSize table | table <- lst] + 2
-        mapM_ put lst
-
-    get = TableList <$> (getWord16be >>= \s -> innerParse (fromIntegral s - 2))
-      where innerParse :: Int -> Get [a]
-            innerParse 0    = return []
-            innerParse size = do
-                onStart <- fromIntegral <$> bytesRead
-                table <- get
-                onEnd <- fromIntegral <$> bytesRead
-                (table :) <$> innerParse (size - (onEnd - onStart))
-
-instance SizeCalculable JpgQuantTableSpec where
-    calculateSize table =
-        1 + (fromIntegral (quantPrecision table) + 1) * 64
-
-instance Binary JpgQuantTableSpec where
-    put table = do
-        let precision = quantPrecision table
-        put4BitsOfEach precision (quantDestination table)
-        forM_ (VS.toList $ quantTable table) $ \coeff ->
-            if precision == 0 then putWord8 $ fromIntegral coeff
-                             else putWord16be $ fromIntegral coeff
-
-    get = do
-        (precision, dest) <- get4BitOfEach
-        coeffs <- replicateM 64 $ if precision == 0
-                then fromIntegral <$> getWord8
-                else fromIntegral <$> getWord16be
-        return JpgQuantTableSpec
-            { quantPrecision = precision
-            , quantDestination = dest
-            , quantTable = VS.fromListN 64 coeffs
-            }
-
-data JpgHuffmanTableSpec = JpgHuffmanTableSpec
-    { -- | 0 : DC, 1 : AC, stored on 4 bits
-      huffmanTableClass       :: !DctComponent
-      -- | Stored on 4 bits
-    , huffmanTableDest        :: !Word8
-
-    , huffSizes :: !(VU.Vector Word8)
-    , huffCodes :: !(V.Vector (VU.Vector Word8))
-    }
-    deriving Show
-
-instance SizeCalculable JpgHuffmanTableSpec where
-    calculateSize table = 1 + 16 + sum [fromIntegral e | e <- VU.toList $ huffSizes table]
-
-instance Binary JpgHuffmanTableSpec where
-    put table = do
-        let classVal = if huffmanTableClass table == DcComponent
-                          then 0 else 1
-        put4BitsOfEach classVal $ huffmanTableDest table
-        mapM_ put . VU.toList $ huffSizes table
-        forM_ [0 .. 15] $ \i ->
-            when (huffSizes table ! i /= 0)
-                 (let elements = VU.toList $ huffCodes table V.! i
-                  in mapM_ put elements)
-
-    get = do
-        (huffClass, huffDest) <- get4BitOfEach
-        sizes <- replicateM 16 getWord8
-        codes <- forM sizes $ \s ->
-            VU.replicateM (fromIntegral s) getWord8
-        return JpgHuffmanTableSpec
-            { huffmanTableClass =
-                if huffClass == 0 then DcComponent else AcComponent
-            , huffmanTableDest = huffDest
-            , huffSizes = VU.fromListN 16 sizes
-            , huffCodes = V.fromListN 16 codes
-            }
-
-instance Binary JpgImage where
-    put (JpgImage { jpgFrame = frames }) =
-        putWord8 0xFF >> putWord8 0xD8 >> mapM_ putFrame frames
-            >> putWord8 0xFF >> putWord8 0xD9
-
-    get = do
-        let startOfImageMarker = 0xD8
-            -- endOfImageMarker = 0xD9
-        checkMarker commonMarkerFirstByte startOfImageMarker
-        eatUntilCode
-        frames <- parseFrames
-        {-checkMarker commonMarkerFirstByte endOfImageMarker-}
-        return JpgImage { jpgFrame = frames }
-
-eatUntilCode :: Get ()
-eatUntilCode = do
-    code <- getWord8
-    unless (code == 0xFF) eatUntilCode
-
-takeCurrentFrame :: Get B.ByteString
-takeCurrentFrame = do
-    size <- getWord16be
-    getByteString (fromIntegral size - 2)
-
-putFrame :: JpgFrame -> Put
-putFrame (JpgAdobeAPP14 adobe) = 
-    put (JpgAppSegment 14) >> putWord16be 14 >> put adobe
-putFrame (JpgJFIF jfif) =
-    put (JpgAppSegment 0) >> putWord16be (14+2) >> put jfif
-putFrame (JpgExif exif) = putExif exif
-putFrame (JpgAppFrame appCode str) =
-    put (JpgAppSegment appCode) >> putWord16be (fromIntegral $ B.length str) >> put str
-putFrame (JpgExtension appCode str) =
-    put (JpgExtensionSegment appCode) >> putWord16be (fromIntegral $ B.length str) >> put str
-putFrame (JpgQuantTable tables) =
-    put JpgQuantizationTable >> put (TableList tables)
-putFrame (JpgHuffmanTable tables) =
-    put JpgHuffmanTableMarker >> put (TableList $ map fst tables)
-putFrame (JpgIntervalRestart size) =
-    put JpgRestartInterval >> put (RestartInterval size)
-putFrame (JpgScanBlob hdr blob) =
-    put JpgStartOfScan >> put hdr >> putLazyByteString blob
-putFrame (JpgScans kind hdr) =
-    put kind >> put hdr
-
---------------------------------------------------
-----            Serialization instances
---------------------------------------------------
-commonMarkerFirstByte :: Word8
-commonMarkerFirstByte = 0xFF
-
-checkMarker :: Word8 -> Word8 -> Get ()
-checkMarker b1 b2 = do
-    rb1 <- getWord8
-    rb2 <- getWord8
-    when (rb1 /= b1 || rb2 /= b2)
-         (fail "Invalid marker used")
-
-extractScanContent :: L.ByteString -> (L.ByteString, L.ByteString)
-extractScanContent str = aux 0
-  where maxi = fromIntegral $ L.length str - 1
-
-        aux n | n >= maxi = (str, L.empty)
-              | v == 0xFF && vNext /= 0 && not isReset = L.splitAt n str
-              | otherwise = aux (n + 1)
-            where v = str `L.index` n
-                  vNext = str `L.index` (n + 1)
-                  isReset = 0xD0 <= vNext && vNext <= 0xD7
-
-parseAdobe14 :: B.ByteString -> [JpgFrame] -> [JpgFrame]
-parseAdobe14 str lst = go where
-  go = case runGetStrict get str of
-    Left _err -> lst
-    Right app14 -> JpgAdobeAPP14 app14 : lst
-
--- | Parse JFIF or JFXX information. Right now only JFIF.
-parseJF__  :: B.ByteString -> [JpgFrame] -> [JpgFrame]
-parseJF__  str lst = go where
-  go = case runGetStrict get str of
-    Left _err -> lst
-    Right jfif -> JpgJFIF jfif : lst
-
-parseExif :: B.ByteString -> [JpgFrame] -> [JpgFrame]
-parseExif str lst 
-  | exifHeader `B.isPrefixOf` str = go
-  | otherwise = lst
-  where
-    exifHeader = BC.pack "Exif\0\0"
-    tiff = B.drop (B.length exifHeader) str
-    go = case runGetStrict (getP tiff) tiff of
-      Left _err -> lst
-      Right (_hdr :: TiffHeader, []) -> lst
-      Right (_hdr :: TiffHeader, ifds : _) -> JpgExif ifds : lst
-
-putExif :: [ImageFileDirectory] -> Put
-putExif ifds = putAll where
-  hdr = TiffHeader
-    { hdrEndianness = EndianBig
-    , hdrOffset = 8
-    }
-
-  ifdList = case partition (isInIFD0 . ifdIdentifier) ifds of
-    (ifd0, []) -> [ifd0]
-    (ifd0, ifdExif) -> [ifd0 <> pure exifOffsetIfd, ifdExif]
-  
-  exifBlob = runPut $ do
-    putByteString $ BC.pack "Exif\0\0"
-    putP BC.empty (hdr, ifdList)
-
-  putAll = do
-    put (JpgAppSegment 1)
-    putWord16be . fromIntegral $ L.length exifBlob + 2
-    putLazyByteString exifBlob
-
-parseFrames :: Get [JpgFrame]
-parseFrames = do
-    kind <- get
-    let parseNextFrame = do
-            word <- getWord8
-            when (word /= 0xFF) $ do
-                readedData <- bytesRead
-                fail $ "Invalid Frame marker (" ++ show word
-                     ++ ", bytes read : " ++ show readedData ++ ")"
-            parseFrames
-
-    case kind of
-        JpgEndOfImage -> return []
-        JpgAppSegment 0 ->
-            parseJF__ <$> takeCurrentFrame <*> parseNextFrame
-        JpgAppSegment 1 ->
-            parseExif <$> takeCurrentFrame <*> parseNextFrame
-        JpgAppSegment 14 ->
-            parseAdobe14 <$> takeCurrentFrame <*> parseNextFrame
-        JpgAppSegment c ->
-            (\frm lst -> JpgAppFrame c frm : lst) <$> takeCurrentFrame <*> parseNextFrame
-        JpgExtensionSegment c ->
-            (\frm lst -> JpgExtension c frm : lst) <$> takeCurrentFrame <*> parseNextFrame
-        JpgQuantizationTable ->
-            (\(TableList quants) lst -> JpgQuantTable quants : lst) <$> get <*> parseNextFrame
-        JpgRestartInterval ->
-            (\(RestartInterval i) lst -> JpgIntervalRestart i : lst) <$> get <*> parseNextFrame
-        JpgHuffmanTableMarker ->
-            (\(TableList huffTables) lst ->
-                    JpgHuffmanTable [(t, packHuffmanTree . buildPackedHuffmanTree $ huffCodes t) | t <- huffTables] : lst)
-                    <$> get <*> parseNextFrame
-        JpgStartOfScan ->
-            (\frm imgData ->
-                let (d, other) = extractScanContent imgData
-                in
-                case runGet parseFrames (L.drop 1 other) of
-                  Left _ -> [JpgScanBlob frm d]
-                  Right lst -> JpgScanBlob frm d : lst
-            ) <$> get <*> getRemainingLazyBytes
-
-        _ -> (\hdr lst -> JpgScans kind hdr : lst) <$> get <*> parseNextFrame
-
-buildPackedHuffmanTree :: V.Vector (VU.Vector Word8) -> HuffmanTree
-buildPackedHuffmanTree = buildHuffmanTree . map VU.toList . V.toList
-
-secondStartOfFrameByteOfKind :: JpgFrameKind -> Word8
-secondStartOfFrameByteOfKind = aux
-  where
-    aux JpgBaselineDCTHuffman = 0xC0
-    aux JpgExtendedSequentialDCTHuffman = 0xC1
-    aux JpgProgressiveDCTHuffman = 0xC2
-    aux JpgLosslessHuffman = 0xC3
-    aux JpgDifferentialSequentialDCTHuffman = 0xC5
-    aux JpgDifferentialProgressiveDCTHuffman = 0xC6
-    aux JpgDifferentialLosslessHuffman = 0xC7
-    aux JpgExtendedSequentialArithmetic = 0xC9
-    aux JpgProgressiveDCTArithmetic = 0xCA
-    aux JpgLosslessArithmetic = 0xCB
-    aux JpgHuffmanTableMarker = 0xC4
-    aux JpgDifferentialSequentialDCTArithmetic = 0xCD
-    aux JpgDifferentialProgressiveDCTArithmetic = 0xCE
-    aux JpgDifferentialLosslessArithmetic = 0xCF
-    aux JpgEndOfImage = 0xD9
-    aux JpgQuantizationTable = 0xDB
-    aux JpgStartOfScan = 0xDA
-    aux JpgRestartInterval = 0xDD
-    aux (JpgRestartIntervalEnd v) = v
-    aux (JpgAppSegment a) = (a + 0xE0)
-    aux (JpgExtensionSegment a) = a
-
-data JpgImageKind = BaseLineDCT | ProgressiveDCT
-
-instance Binary JpgFrameKind where
-    put v = putWord8 0xFF >> put (secondStartOfFrameByteOfKind v)
-    get = do
-        -- no lookahead :(
-        {-word <- getWord8-}
-        word2 <- getWord8
-        return $ case word2 of
-            0xC0 -> JpgBaselineDCTHuffman
-            0xC1 -> JpgExtendedSequentialDCTHuffman
-            0xC2 -> JpgProgressiveDCTHuffman
-            0xC3 -> JpgLosslessHuffman
-            0xC4 -> JpgHuffmanTableMarker
-            0xC5 -> JpgDifferentialSequentialDCTHuffman
-            0xC6 -> JpgDifferentialProgressiveDCTHuffman
-            0xC7 -> JpgDifferentialLosslessHuffman
-            0xC9 -> JpgExtendedSequentialArithmetic
-            0xCA -> JpgProgressiveDCTArithmetic
-            0xCB -> JpgLosslessArithmetic
-            0xCD -> JpgDifferentialSequentialDCTArithmetic
-            0xCE -> JpgDifferentialProgressiveDCTArithmetic
-            0xCF -> JpgDifferentialLosslessArithmetic
-            0xD9 -> JpgEndOfImage
-            0xDA -> JpgStartOfScan
-            0xDB -> JpgQuantizationTable
-            0xDD -> JpgRestartInterval
-            a | a >= 0xF0 -> JpgExtensionSegment a
-              | a >= 0xE0 -> JpgAppSegment (a - 0xE0)
-              | a >= 0xD0 && a <= 0xD7 -> JpgRestartIntervalEnd a
-              | otherwise -> error ("Invalid frame marker (" ++ show a ++ ")")
-
-put4BitsOfEach :: Word8 -> Word8 -> Put
-put4BitsOfEach a b = put $ (a `unsafeShiftL` 4) .|. b
-
-get4BitOfEach :: Get (Word8, Word8)
-get4BitOfEach = do
-    val <- get
-    return ((val `unsafeShiftR` 4) .&. 0xF, val .&. 0xF)
-
-newtype RestartInterval = RestartInterval Word16
-
-instance Binary RestartInterval where
-    put (RestartInterval i) = putWord16be 4 >> putWord16be i
-    get = do
-        size <- getWord16be
-        when (size /= 4) (fail "Invalid jpeg restart interval size")
-        RestartInterval <$> getWord16be
-
-instance Binary JpgComponent where
-    get = do
-        ident <- getWord8
-        (horiz, vert) <- get4BitOfEach
-        quantTableIndex <- getWord8
-        return JpgComponent
-            { componentIdentifier = ident
-            , horizontalSamplingFactor = horiz
-            , verticalSamplingFactor = vert
-            , quantizationTableDest = quantTableIndex
-            }
-    put v = do
-        put $ componentIdentifier v
-        put4BitsOfEach (horizontalSamplingFactor v) $ verticalSamplingFactor v
-        put $ quantizationTableDest v
-
-instance Binary JpgFrameHeader where
-    get = do
-        beginOffset <- fromIntegral <$> bytesRead
-        frmHLength <- getWord16be
-        samplePrec <- getWord8
-        h <- getWord16be
-        w <- getWord16be
-        compCount <- getWord8
-        components <- replicateM (fromIntegral compCount) get
-        endOffset <- fromIntegral <$> bytesRead
-        when (beginOffset - endOffset < fromIntegral frmHLength)
-             (skip $ fromIntegral frmHLength - (endOffset - beginOffset))
-        return JpgFrameHeader
-            { jpgFrameHeaderLength = frmHLength
-            , jpgSamplePrecision = samplePrec
-            , jpgHeight = h
-            , jpgWidth = w
-            , jpgImageComponentCount = compCount
-            , jpgComponents = components
-            }
-
-    put v = do
-        putWord16be $ jpgFrameHeaderLength v
-        putWord8    $ jpgSamplePrecision v
-        putWord16be $ jpgHeight v
-        putWord16be $ jpgWidth v
-        putWord8    $ jpgImageComponentCount v
-        mapM_ put   $ jpgComponents v
-
-instance Binary JpgScanSpecification where
-    put v = do
-        put $ componentSelector v
-        put4BitsOfEach (dcEntropyCodingTable v) $ acEntropyCodingTable v
-
-    get = do
-        compSel <- get
-        (dc, ac) <- get4BitOfEach
-        return JpgScanSpecification {
-            componentSelector = compSel
-          , dcEntropyCodingTable = dc
-          , acEntropyCodingTable = ac
-          }
-
-instance Binary JpgScanHeader where
-    get = do
-        thisScanLength <- getWord16be
-        compCount <- getWord8
-        comp <- replicateM (fromIntegral compCount) get
-        specBeg <- get
-        specEnd <- get
-        (approxHigh, approxLow) <- get4BitOfEach
-
-        return JpgScanHeader {
-            scanLength = thisScanLength,
-            scanComponentCount = compCount,
-            scans = comp,
-            spectralSelection = (specBeg, specEnd),
-            successiveApproxHigh = approxHigh,
-            successiveApproxLow = approxLow
-        }
-
-    put v = do
-        putWord16be $ scanLength v
-        putWord8 $ scanComponentCount v
-        mapM_ put $ scans v
-        putWord8 . fst $ spectralSelection v
-        putWord8 . snd $ spectralSelection v
-        put4BitsOfEach (successiveApproxHigh v) $ successiveApproxLow v
-
-{-# INLINE createEmptyMutableMacroBlock #-}
--- | Create a new macroblock with the good array size
-createEmptyMutableMacroBlock :: (Storable a, Num a) => ST s (MutableMacroBlock s a)
-createEmptyMutableMacroBlock = M.replicate 64 0
-
-printMacroBlock :: (Storable a, PrintfArg a)
-                => MutableMacroBlock s a -> ST s String
-printMacroBlock block = pLn 0
-    where pLn 64 = return "===============================\n"
-          pLn i = do
-              v <- block `M.unsafeRead` i
-              vn <- pLn (i+1)
-              return $ printf (if i `mod` 8 == 0 then "\n%5d " else "%5d ") v ++ vn
-
-printPureMacroBlock :: (Storable a, PrintfArg a) => MacroBlock a -> String
-printPureMacroBlock block = pLn 0
-    where pLn 64 = "===============================\n"
-          pLn i = str ++ pLn (i + 1)
-            where str | i `mod` 8 == 0 = printf "\n%5d " v
-                      | otherwise = printf "%5d" v
-                  v = block VS.! i
-
-
-{-# INLINE dctBlockSize #-}
-dctBlockSize :: Num a => a
-dctBlockSize = 8
src/Codec/Picture/Metadata.hs view
@@ -17,6 +17,7 @@                              , Value( .. )
                              , Elem( .. )
                              , SourceFormat( .. )
+                             , ColorSpace( .. )
 
                                -- * Functions
                              , Codec.Picture.Metadata.lookup
@@ -42,6 +43,8 @@                              , dotsPerCentiMeterToDotPerInch
                              ) where
 
+import Prelude hiding (Foldable(..))
+
 #if !MIN_VERSION_base(4,8,0)
 import Data.Monoid( Monoid, mempty, mappend )
 import Data.Word( Word )
@@ -49,6 +52,7 @@ 
 
 import Control.DeepSeq( NFData( .. ) )
+import qualified Data.ByteString as B
 import qualified Data.Foldable as F
 
 import Codec.Picture.Metadata.Exif
@@ -61,7 +65,7 @@     Refl :: Equiv a a
 #endif
 
--- | Type describing the original file format of the ilfe.
+-- | Type describing the original file format of the file.
 data SourceFormat
   = SourceJpeg
   | SourceGif
@@ -75,6 +79,38 @@ instance NFData SourceFormat where
   rnf a = a `seq` ()
 
+-- | The same color values may result in slightly different colors on different
+-- devices. To get consistent colors accross multiple devices we need a way of
+-- mapping color values from a source device into their equivalents on the
+-- target device.
+--
+-- The solution is essentially to define, for each device, a family of mappings
+-- that convert between device colors and standard CIEXYZ or CIELAB colors. The
+-- collection of mappings for a device is known as the 'color-profile' of that
+-- device, and each color-profile can be thought of as describing a
+-- 'color-space'.
+--
+-- If we know the color-space of the input pixels, and the color space of the
+-- output device, then we can convert the colors in the image to their
+-- equivalents on the output device.
+--
+-- JuicyPixels does not parse color-profiles or attempt to perform color
+-- correction.
+--
+-- The following color space types are recognised:
+--
+--   * sRGB: Standard RGB color space.
+--   * Windows BMP color space: Color space information embedded within a V4
+--         Windows BMP file.
+--   * ICC profile: An ICC color profile.
+data ColorSpace = SRGB
+                | WindowsBitmapColorSpace !B.ByteString
+                | ICCProfile !B.ByteString
+                deriving (Eq, Show)
+
+instance NFData ColorSpace where
+  rnf v = v `seq` ()
+
 -- | Store various additional information about an image. If
 -- something is not recognized, it can be stored in an unknown tag.
 --
@@ -86,16 +122,20 @@ --          information can avoid the full decompression of the image.
 --          Ignored for image writing.
 --
---   * 'Height' Image height in pixels. Relyiung on the metadata for this
---          information can void the full decomrpession of the image.
+--   * 'Height' Image height in pixels. Relying on the metadata for this
+--          information can void the full decompression of the image.
 --          Ignored for image writing.
 --
+--   * 'ColorProfile' An unparsed ICC color profile. Currently only supported by
+--          the Bitmap format.
+--
 --   * 'Unknown' unlikely to be decoded, but usefull for metadata writing
 --
 --   * 'Exif' Exif tag and associated data.
 --
 data Keys a where
   Gamma       :: Keys Double
+  ColorSpace  :: Keys ColorSpace
   Format      :: Keys SourceFormat
   DpiX        :: Keys Word
   DpiY        :: Keys Word
@@ -140,6 +180,7 @@ keyEq :: Keys a -> Keys b -> Maybe (Equiv a b)
 keyEq a b = case (a, b) of
   (Gamma, Gamma) -> Just Refl
+  (ColorSpace, ColorSpace) -> Just Refl
   (DpiX, DpiX) -> Just Refl
   (DpiY, DpiY) -> Just Refl
   (Width, Width) -> Just Refl
src/Codec/Picture/Metadata/Exif.hs view
@@ -1,3 +1,5 @@+{-# LANGUAGE DeriveGeneric #-}
+
 -- | This module provide a totally partial and incomplete maping
 -- of Exif values. Used for Tiff parsing and reused for Exif extraction.
 module Codec.Picture.Metadata.Exif ( ExifTag( .. )
@@ -14,6 +16,7 @@ import Data.Word( Word16, Word32 )
 import qualified Data.Vector as V
 import qualified Data.ByteString as B
+import GHC.Generics( Generic )
 
 -- | Tag values used for exif fields. Completly incomplete
 data ExifTag
@@ -72,7 +75,8 @@ 
   | TagExifOffset
   | TagUnknown !Word16
-  deriving (Eq, Ord, Show)
+  deriving (Eq, Ord, Show, Generic)
+instance NFData ExifTag
 
 -- | Convert a value to it's corresponding Exif tag.
 -- Will often be written as 'TagUnknown'
@@ -206,13 +210,5 @@   | ExifRational  !Word32 !Word32
   | ExifSignedRational  !Int32 !Int32
   | ExifIFD       ![(ExifTag, ExifData)]
-  deriving Show
-
-instance NFData ExifTag where
-  rnf a = a `seq` ()
-
-instance NFData ExifData where
-  rnf (ExifIFD ifds) = rnf ifds `seq` ()
-  rnf (ExifLongs l) = rnf l `seq` ()
-  rnf (ExifShorts l) = rnf l `seq` ()
-  rnf a = a `seq` ()
+  deriving (Eq, Show, Generic)
+instance NFData ExifData
src/Codec/Picture/Png.hs view
@@ -26,8 +26,6 @@ 
                         , writePng
                         , encodeDynamicPng
-                        , encodePalettedPng
-                        , encodePalettedPngWithMetadata
                         , writeDynamicPng
                         ) where
 
@@ -38,7 +36,11 @@ import Control.Arrow( first )
 import Control.Monad( forM_, foldM_, when, void )
 import Control.Monad.ST( ST, runST )
+
+#if !MIN_VERSION_base(4,11,0)
 import Data.Monoid( (<>) )
+#endif
+
 import Data.Binary( Binary( get) )
 
 import qualified Data.Vector.Storable as V
@@ -54,9 +56,9 @@ 
 import Codec.Picture.Types
 import Codec.Picture.Metadata
-import Codec.Picture.Png.Type
-import Codec.Picture.Png.Export
-import Codec.Picture.Png.Metadata
+import Codec.Picture.Png.Internal.Type
+import Codec.Picture.Png.Internal.Export
+import Codec.Picture.Png.Internal.Metadata
 import Codec.Picture.InternalHelper
 
 -- | Simple structure used to hold information about Adam7 deinterlacing.
@@ -364,8 +366,8 @@ deinterlacer :: PngIHdr -> B.ByteString -> ST s (Either (V.Vector Word8) (V.Vector Word16))
 deinterlacer (PngIHdr { width = w, height = h, colourType  = imgKind
                       , interlaceMethod = method, bitDepth = depth  }) str = do
-    let compCount = sampleCountOfImageType imgKind 
-        arraySize = fromIntegral $ w * h * compCount
+    let compCount = fromIntegral $ sampleCountOfImageType imgKind 
+        arraySize = (fromIntegral w) * (fromIntegral h) * compCount
         deinterlaceFunction = case method of
             PngNoInterlace -> scanLineInterleaving
             PngInterlaceAdam7 -> adam7Unpack
@@ -375,10 +377,9 @@         imgArray <- M.new arraySize
         let mutableImage = MutableImage (fromIntegral w) (fromIntegral h) imgArray
         deinterlaceFunction iBitDepth 
-                            (fromIntegral compCount)
+                            compCount
                             (fromIntegral w, fromIntegral h)
-                            (scanlineUnpacker8 iBitDepth (fromIntegral compCount)
-                                                         mutableImage)
+                            (scanlineUnpacker8 iBitDepth compCount mutableImage)
                             str
         Left <$> V.unsafeFreeze imgArray
 
@@ -386,9 +387,9 @@         imgArray <- M.new arraySize
         let mutableImage = MutableImage (fromIntegral w) (fromIntegral h) imgArray
         deinterlaceFunction iBitDepth 
-                            (fromIntegral compCount)
+                            compCount
                             (fromIntegral w, fromIntegral h)
-                            (shortUnpacker (fromIntegral compCount) mutableImage)
+                            (shortUnpacker compCount mutableImage)
                             str
         Right <$> V.unsafeFreeze imgArray
 
− src/Codec/Picture/Png/Export.hs
@@ -1,268 +0,0 @@-{-# LANGUAGE CPP #-}
-{-# LANGUAGE FlexibleContexts #-}
-{-# LANGUAGE TypeSynonymInstances #-}
-{-# LANGUAGE TypeFamilies #-}
-{-# LANGUAGE ScopedTypeVariables #-}
--- | Module implementing a basic png export, no filtering is applyed, but
--- export at least valid images.
-module Codec.Picture.Png.Export( PngSavable( .. )
-                               , PngPaletteSaveable( .. )
-                               , writePng
-                               , encodeDynamicPng
-                               , writeDynamicPng
-                               ) where
-#if !MIN_VERSION_base(4,8,0)
-import Data.Monoid( mempty )
-#endif
-
-import Control.Monad( forM_ )
-import Control.Monad.ST( ST, runST )
-import Data.Bits( unsafeShiftR, (.&.) )
-import Data.Binary( encode )
-import Data.Monoid( (<>) )
-import Data.Word(Word8, Word16)
-import qualified Codec.Compression.Zlib as Z
-import qualified Data.ByteString as B
-import qualified Data.ByteString.Lazy as Lb
-
-import qualified Data.Vector.Storable as VS
-import qualified Data.Vector.Storable.Mutable as M
-
-import Codec.Picture.Types
-import Codec.Picture.Png.Type
-import Codec.Picture.Png.Metadata
-import Codec.Picture.Metadata( Metadatas )
-import Codec.Picture.VectorByteConversion( blitVector, toByteString )
-
--- | Encode a paletted image into a png if possible.
-class PngPaletteSaveable a where
-  -- | Encode a paletted image as a color indexed 8-bit PNG.
-  -- the palette must have between 1 and 256 values in it.
-  -- Accepts `PixelRGB8` and `PixelRGBA8` as palette pixel type
-  encodePalettedPng :: Image a -> Image Pixel8 -> Either String Lb.ByteString
-  encodePalettedPng = encodePalettedPngWithMetadata mempty
-
-  -- | Equivalent to 'encodePalettedPng' but allow writing of metadatas.
-  -- See `encodePngWithMetadata` for the details of encoded metadatas
-  -- Accepts `PixelRGB8` and `PixelRGBA8` as palette pixel type
-  encodePalettedPngWithMetadata :: Metadatas -> Image a -> Image Pixel8 -> Either String Lb.ByteString
-
-instance PngPaletteSaveable PixelRGB8 where
-  encodePalettedPngWithMetadata metas pal img
-      | w <= 0 || w > 256 || h /= 1 = Left "Invalid palette"
-      | VS.any isTooBig $ imageData img =
-          Left "Image contains indexes absent from the palette"
-      | otherwise = Right $ genericEncodePng (Just pal) Nothing PngIndexedColor metas img
-        where w = imageWidth pal
-              h = imageHeight pal
-              isTooBig v = fromIntegral v >= w
-
-instance PngPaletteSaveable PixelRGBA8 where
-  encodePalettedPngWithMetadata metas pal img
-      | w <= 0 || w > 256 || h /= 1 = Left "Invalid palette"
-      | VS.any isTooBig $ imageData img =
-          Left "Image contains indexes absent from the palette"
-      | otherwise = Right $ genericEncodePng (Just opaquePalette) (Just alphaPal) PngIndexedColor metas img
-    where
-      w = imageWidth pal
-      h = imageHeight pal
-      opaquePalette = dropAlphaLayer pal
-      alphaPal = imageData $ extractComponent PlaneAlpha pal
-      isTooBig v = fromIntegral v >= w
-
--- | Encode an image into a png if possible.
-class PngSavable a where
-    -- | Transform an image into a png encoded bytestring, ready
-    -- to be written as a file.
-    encodePng :: Image a -> Lb.ByteString
-    encodePng = encodePngWithMetadata mempty
-
-    -- | Encode a png using some metadatas. The following metadata keys will
-    -- be stored in a `tEXt` field :
-    --
-    --  * 'Codec.Picture.Metadata.Title'
-    --  * 'Codec.Picture.Metadata.Description'
-    --  * 'Codec.Picture.Metadata.Author'
-    --  * 'Codec.Picture.Metadata.Copyright'
-    --  * 'Codec.Picture.Metadata.Software'
-    --  * 'Codec.Picture.Metadata.Comment'
-    --  * 'Codec.Picture.Metadata.Disclaimer'
-    --  * 'Codec.Picture.Metadata.Source'
-    --  * 'Codec.Picture.Metadata.Warning'
-    --  * 'Codec.Picture.Metadata.Unknown' using the key present in the constructor.
-    -- 
-    -- the followings metadata will bes tored in the `gAMA` chunk.
-    --
-    --  * 'Codec.Picture.Metadata.Gamma'
-    --
-    -- The followings metadata will be stored in a `pHYs` chunk
-    --
-    --  * 'Codec.Picture.Metadata.DpiX'
-    --  * 'Codec.Picture.Metadata.DpiY' 
-    encodePngWithMetadata :: Metadatas -> Image a -> Lb.ByteString
-
-preparePngHeader :: Image a -> PngImageType -> Word8 -> PngIHdr
-preparePngHeader (Image { imageWidth = w, imageHeight = h }) imgType depth = PngIHdr
-  { width             = fromIntegral w
-  , height            = fromIntegral h
-  , bitDepth          = depth
-  , colourType        = imgType
-  , compressionMethod = 0
-  , filterMethod      = 0
-  , interlaceMethod   = PngNoInterlace
-  }
-
--- | Helper function to directly write an image as a png on disk.
-writePng :: (PngSavable pixel) => FilePath -> Image pixel -> IO ()
-writePng path img = Lb.writeFile path $ encodePng img
-
-endChunk :: PngRawChunk
-endChunk = mkRawChunk iENDSignature mempty
-
-prepareIDatChunk :: Lb.ByteString -> PngRawChunk
-prepareIDatChunk = mkRawChunk iDATSignature
-
-genericEncode16BitsPng :: forall px. (Pixel px, PixelBaseComponent px ~ Word16)
-                       => PngImageType -> Metadatas -> Image px -> Lb.ByteString
-genericEncode16BitsPng imgKind metas
-                 image@(Image { imageWidth = w, imageHeight = h, imageData = arr }) =
-  encode PngRawImage { header = hdr
-                     , chunks = encodeMetadatas metas 
-                              <> [ prepareIDatChunk imgEncodedData
-                                 , endChunk
-                                 ]
-                     }
-    where hdr = preparePngHeader image imgKind 16
-          zero = B.singleton 0
-          compCount = componentCount (undefined :: px)
-
-          lineSize = compCount * w
-          blitToByteString vec = blitVector vec 0 (lineSize * 2)
-          encodeLine line = blitToByteString $ runST $ do
-              finalVec <- M.new $ lineSize * 2 :: ST s (M.STVector s Word8)
-              let baseIndex = line * lineSize
-              forM_ [0 ..  lineSize - 1] $ \ix -> do
-                  let v = arr `VS.unsafeIndex` (baseIndex + ix)
-                      high = fromIntegral $ (v `unsafeShiftR` 8) .&. 0xFF
-                      low = fromIntegral $ v .&. 0xFF
-
-                  (finalVec `M.unsafeWrite` (ix * 2 + 0)) high
-                  (finalVec `M.unsafeWrite` (ix * 2 + 1)) low
-
-              VS.unsafeFreeze finalVec
-
-          imgEncodedData = Z.compress . Lb.fromChunks
-                        $ concat [[zero, encodeLine line] | line <- [0 .. h - 1]]
-
-preparePalette :: Palette -> PngRawChunk
-preparePalette pal = PngRawChunk
-  { chunkLength = fromIntegral $ imageWidth pal * 3
-  , chunkType   = pLTESignature
-  , chunkCRC    = pngComputeCrc [pLTESignature, binaryData]
-  , chunkData   = binaryData
-  }
-  where binaryData = Lb.fromChunks [toByteString $ imageData pal]
-
-preparePaletteAlpha :: VS.Vector Pixel8 -> PngRawChunk
-preparePaletteAlpha alphaPal = PngRawChunk
-  { chunkLength = fromIntegral $ VS.length alphaPal
-  , chunkType   = tRNSSignature
-  , chunkCRC    = pngComputeCrc [tRNSSignature, binaryData]
-  , chunkData   = binaryData
-  }
-  where binaryData = Lb.fromChunks [toByteString alphaPal]
-
-type PaletteAlpha = VS.Vector Pixel8
-
-genericEncodePng :: forall px. (Pixel px, PixelBaseComponent px ~ Word8)
-                 => Maybe Palette
-                 -> Maybe PaletteAlpha
-                 -> PngImageType -> Metadatas -> Image px
-                 -> Lb.ByteString
-genericEncodePng palette palAlpha imgKind metas
-                 image@(Image { imageWidth = w, imageHeight = h, imageData = arr }) =
-  encode PngRawImage { header = hdr
-                     , chunks = encodeMetadatas metas
-                              <> paletteChunk
-                              <> transpChunk
-                              <> [ prepareIDatChunk imgEncodedData
-                                 , endChunk
-                                 ]}
-  where
-    hdr = preparePngHeader image imgKind 8
-    zero = B.singleton 0
-    compCount = componentCount (undefined :: px)
-
-    paletteChunk = case palette of
-      Nothing -> []
-      Just p -> [preparePalette p]
-
-    transpChunk = case palAlpha of
-      Nothing -> []
-      Just p -> [preparePaletteAlpha p]
-
-    lineSize = compCount * w
-    encodeLine line = blitVector arr (line * lineSize) lineSize
-    imgEncodedData = Z.compress
-        . Lb.fromChunks
-        $ concat [[zero, encodeLine line] | line <- [0 .. h - 1]]
-
-instance PngSavable PixelRGBA8 where
-  encodePngWithMetadata = genericEncodePng Nothing Nothing PngTrueColourWithAlpha
-
-instance PngSavable PixelRGB8 where
-  encodePngWithMetadata = genericEncodePng Nothing Nothing PngTrueColour
-
-instance PngSavable Pixel8 where
-  encodePngWithMetadata = genericEncodePng Nothing Nothing PngGreyscale
-
-instance PngSavable PixelYA8 where
-  encodePngWithMetadata = genericEncodePng Nothing Nothing PngGreyscaleWithAlpha
-
-instance PngSavable PixelYA16 where
-  encodePngWithMetadata = genericEncode16BitsPng PngGreyscaleWithAlpha
-
-instance PngSavable Pixel16 where
-  encodePngWithMetadata = genericEncode16BitsPng PngGreyscale
-
-instance PngSavable PixelRGB16 where
-  encodePngWithMetadata = genericEncode16BitsPng PngTrueColour
-
-instance PngSavable PixelRGBA16 where
-  encodePngWithMetadata = genericEncode16BitsPng PngTrueColourWithAlpha
-
--- | Write a dynamic image in a .png image file if possible.
--- The same restriction as encodeDynamicPng apply.
-writeDynamicPng :: FilePath -> DynamicImage -> IO (Either String Bool)
-writeDynamicPng path img = case encodeDynamicPng img of
-        Left err -> return $ Left err
-        Right b  -> Lb.writeFile path b >> return (Right True)
-
--- | Encode a dynamic image in PNG if possible, supported images are:
---
---   * 'ImageY8'
---
---   * 'ImageY16'
---
---   * 'ImageYA8'
---
---   * 'ImageYA16'
---
---   * 'ImageRGB8'
---
---   * 'ImageRGB16'
---
---   * 'ImageRGBA8'
---
---   * 'ImageRGBA16'
---
-encodeDynamicPng :: DynamicImage -> Either String Lb.ByteString
-encodeDynamicPng (ImageRGB8 img) = Right $ encodePng img
-encodeDynamicPng (ImageRGBA8 img) = Right $ encodePng img
-encodeDynamicPng (ImageY8 img) = Right $ encodePng img
-encodeDynamicPng (ImageY16 img) = Right $ encodePng img
-encodeDynamicPng (ImageYA8 img) = Right $ encodePng img
-encodeDynamicPng (ImageYA16 img) = Right $ encodePng img
-encodeDynamicPng (ImageRGB16 img) = Right $ encodePng img
-encodeDynamicPng (ImageRGBA16 img) = Right $ encodePng img
-encodeDynamicPng _ = Left "Unsupported image format for PNG export"
+ src/Codec/Picture/Png/Internal/Export.hs view
@@ -0,0 +1,270 @@+{-# LANGUAGE CPP #-}
+{-# LANGUAGE FlexibleContexts #-}
+{-# LANGUAGE TypeSynonymInstances #-}
+{-# LANGUAGE TypeFamilies #-}
+{-# LANGUAGE ScopedTypeVariables #-}
+-- | Module implementing a basic png export, no filtering is applyed, but
+-- export at least valid images.
+module Codec.Picture.Png.Internal.Export( PngSavable( .. )
+                               , PngPaletteSaveable( .. )
+                               , writePng
+                               , encodeDynamicPng
+                               , writeDynamicPng
+                               ) where
+#if !MIN_VERSION_base(4,8,0)
+import Data.Monoid( mempty )
+#endif
+
+import Control.Monad( forM_ )
+import Control.Monad.ST( ST, runST )
+import Data.Bits( unsafeShiftR, (.&.) )
+import Data.Binary( encode )
+#if !MIN_VERSION_base(4,11,0)
+import Data.Monoid( (<>) )
+#endif
+import Data.Word(Word8, Word16)
+import qualified Codec.Compression.Zlib as Z
+import qualified Data.ByteString as B
+import qualified Data.ByteString.Lazy as Lb
+
+import qualified Data.Vector.Storable as VS
+import qualified Data.Vector.Storable.Mutable as M
+
+import Codec.Picture.Types
+import Codec.Picture.Png.Internal.Type
+import Codec.Picture.Png.Internal.Metadata
+import Codec.Picture.Metadata( Metadatas )
+import Codec.Picture.VectorByteConversion( blitVector, toByteString )
+
+-- | Encode a paletted image into a png if possible.
+class PngPaletteSaveable a where
+  -- | Encode a paletted image as a color indexed 8-bit PNG.
+  -- the palette must have between 1 and 256 values in it.
+  -- Accepts `PixelRGB8` and `PixelRGBA8` as palette pixel type
+  encodePalettedPng :: Image a -> Image Pixel8 -> Either String Lb.ByteString
+  encodePalettedPng = encodePalettedPngWithMetadata mempty
+
+  -- | Equivalent to 'encodePalettedPng' but allow writing of metadatas.
+  -- See `encodePngWithMetadata` for the details of encoded metadatas
+  -- Accepts `PixelRGB8` and `PixelRGBA8` as palette pixel type
+  encodePalettedPngWithMetadata :: Metadatas -> Image a -> Image Pixel8 -> Either String Lb.ByteString
+
+instance PngPaletteSaveable PixelRGB8 where
+  encodePalettedPngWithMetadata metas pal img
+      | w <= 0 || w > 256 || h /= 1 = Left "Invalid palette"
+      | VS.any isTooBig $ imageData img =
+          Left "Image contains indexes absent from the palette"
+      | otherwise = Right $ genericEncodePng (Just pal) Nothing PngIndexedColor metas img
+        where w = imageWidth pal
+              h = imageHeight pal
+              isTooBig v = fromIntegral v >= w
+
+instance PngPaletteSaveable PixelRGBA8 where
+  encodePalettedPngWithMetadata metas pal img
+      | w <= 0 || w > 256 || h /= 1 = Left "Invalid palette"
+      | VS.any isTooBig $ imageData img =
+          Left "Image contains indexes absent from the palette"
+      | otherwise = Right $ genericEncodePng (Just opaquePalette) (Just alphaPal) PngIndexedColor metas img
+    where
+      w = imageWidth pal
+      h = imageHeight pal
+      opaquePalette = dropAlphaLayer pal
+      alphaPal = imageData $ extractComponent PlaneAlpha pal
+      isTooBig v = fromIntegral v >= w
+
+-- | Encode an image into a png if possible.
+class PngSavable a where
+    -- | Transform an image into a png encoded bytestring, ready
+    -- to be written as a file.
+    encodePng :: Image a -> Lb.ByteString
+    encodePng = encodePngWithMetadata mempty
+
+    -- | Encode a png using some metadatas. The following metadata keys will
+    -- be stored in a `tEXt` field :
+    --
+    --  * 'Codec.Picture.Metadata.Title'
+    --  * 'Codec.Picture.Metadata.Description'
+    --  * 'Codec.Picture.Metadata.Author'
+    --  * 'Codec.Picture.Metadata.Copyright'
+    --  * 'Codec.Picture.Metadata.Software'
+    --  * 'Codec.Picture.Metadata.Comment'
+    --  * 'Codec.Picture.Metadata.Disclaimer'
+    --  * 'Codec.Picture.Metadata.Source'
+    --  * 'Codec.Picture.Metadata.Warning'
+    --  * 'Codec.Picture.Metadata.Unknown' using the key present in the constructor.
+    -- 
+    -- the followings metadata will be stored in the `gAMA` chunk.
+    --
+    --  * 'Codec.Picture.Metadata.Gamma'
+    --
+    -- The followings metadata will be stored in a `pHYs` chunk
+    --
+    --  * 'Codec.Picture.Metadata.DpiX'
+    --  * 'Codec.Picture.Metadata.DpiY' 
+    encodePngWithMetadata :: Metadatas -> Image a -> Lb.ByteString
+
+preparePngHeader :: Image a -> PngImageType -> Word8 -> PngIHdr
+preparePngHeader (Image { imageWidth = w, imageHeight = h }) imgType depth = PngIHdr
+  { width             = fromIntegral w
+  , height            = fromIntegral h
+  , bitDepth          = depth
+  , colourType        = imgType
+  , compressionMethod = 0
+  , filterMethod      = 0
+  , interlaceMethod   = PngNoInterlace
+  }
+
+-- | Helper function to directly write an image as a png on disk.
+writePng :: (PngSavable pixel) => FilePath -> Image pixel -> IO ()
+writePng path img = Lb.writeFile path $ encodePng img
+
+endChunk :: PngRawChunk
+endChunk = mkRawChunk iENDSignature mempty
+
+prepareIDatChunk :: Lb.ByteString -> PngRawChunk
+prepareIDatChunk = mkRawChunk iDATSignature
+
+genericEncode16BitsPng :: forall px. (Pixel px, PixelBaseComponent px ~ Word16)
+                       => PngImageType -> Metadatas -> Image px -> Lb.ByteString
+genericEncode16BitsPng imgKind metas
+                 image@(Image { imageWidth = w, imageHeight = h, imageData = arr }) =
+  encode PngRawImage { header = hdr
+                     , chunks = encodeMetadatas metas 
+                              <> [ prepareIDatChunk imgEncodedData
+                                 , endChunk
+                                 ]
+                     }
+    where hdr = preparePngHeader image imgKind 16
+          zero = B.singleton 0
+          compCount = componentCount (undefined :: px)
+
+          lineSize = compCount * w
+          blitToByteString vec = blitVector vec 0 (lineSize * 2)
+          encodeLine line = blitToByteString $ runST $ do
+              finalVec <- M.new $ lineSize * 2 :: ST s (M.STVector s Word8)
+              let baseIndex = line * lineSize
+              forM_ [0 ..  lineSize - 1] $ \ix -> do
+                  let v = arr `VS.unsafeIndex` (baseIndex + ix)
+                      high = fromIntegral $ (v `unsafeShiftR` 8) .&. 0xFF
+                      low = fromIntegral $ v .&. 0xFF
+
+                  (finalVec `M.unsafeWrite` (ix * 2 + 0)) high
+                  (finalVec `M.unsafeWrite` (ix * 2 + 1)) low
+
+              VS.unsafeFreeze finalVec
+
+          imgEncodedData = Z.compress . Lb.fromChunks
+                        $ concat [[zero, encodeLine line] | line <- [0 .. h - 1]]
+
+preparePalette :: Palette -> PngRawChunk
+preparePalette pal = PngRawChunk
+  { chunkLength = fromIntegral $ imageWidth pal * 3
+  , chunkType   = pLTESignature
+  , chunkCRC    = pngComputeCrc [pLTESignature, binaryData]
+  , chunkData   = binaryData
+  }
+  where binaryData = Lb.fromChunks [toByteString $ imageData pal]
+
+preparePaletteAlpha :: VS.Vector Pixel8 -> PngRawChunk
+preparePaletteAlpha alphaPal = PngRawChunk
+  { chunkLength = fromIntegral $ VS.length alphaPal
+  , chunkType   = tRNSSignature
+  , chunkCRC    = pngComputeCrc [tRNSSignature, binaryData]
+  , chunkData   = binaryData
+  }
+  where binaryData = Lb.fromChunks [toByteString alphaPal]
+
+type PaletteAlpha = VS.Vector Pixel8
+
+genericEncodePng :: forall px. (Pixel px, PixelBaseComponent px ~ Word8)
+                 => Maybe Palette
+                 -> Maybe PaletteAlpha
+                 -> PngImageType -> Metadatas -> Image px
+                 -> Lb.ByteString
+genericEncodePng palette palAlpha imgKind metas
+                 image@(Image { imageWidth = w, imageHeight = h, imageData = arr }) =
+  encode PngRawImage { header = hdr
+                     , chunks = encodeMetadatas metas
+                              <> paletteChunk
+                              <> transpChunk
+                              <> [ prepareIDatChunk imgEncodedData
+                                 , endChunk
+                                 ]}
+  where
+    hdr = preparePngHeader image imgKind 8
+    zero = B.singleton 0
+    compCount = componentCount (undefined :: px)
+
+    paletteChunk = case palette of
+      Nothing -> []
+      Just p -> [preparePalette p]
+
+    transpChunk = case palAlpha of
+      Nothing -> []
+      Just p -> [preparePaletteAlpha p]
+
+    lineSize = compCount * w
+    encodeLine line = blitVector arr (line * lineSize) lineSize
+    imgEncodedData = Z.compress
+        . Lb.fromChunks
+        $ concat [[zero, encodeLine line] | line <- [0 .. h - 1]]
+
+instance PngSavable PixelRGBA8 where
+  encodePngWithMetadata = genericEncodePng Nothing Nothing PngTrueColourWithAlpha
+
+instance PngSavable PixelRGB8 where
+  encodePngWithMetadata = genericEncodePng Nothing Nothing PngTrueColour
+
+instance PngSavable Pixel8 where
+  encodePngWithMetadata = genericEncodePng Nothing Nothing PngGreyscale
+
+instance PngSavable PixelYA8 where
+  encodePngWithMetadata = genericEncodePng Nothing Nothing PngGreyscaleWithAlpha
+
+instance PngSavable PixelYA16 where
+  encodePngWithMetadata = genericEncode16BitsPng PngGreyscaleWithAlpha
+
+instance PngSavable Pixel16 where
+  encodePngWithMetadata = genericEncode16BitsPng PngGreyscale
+
+instance PngSavable PixelRGB16 where
+  encodePngWithMetadata = genericEncode16BitsPng PngTrueColour
+
+instance PngSavable PixelRGBA16 where
+  encodePngWithMetadata = genericEncode16BitsPng PngTrueColourWithAlpha
+
+-- | Write a dynamic image in a .png image file if possible.
+-- The same restriction as encodeDynamicPng apply.
+writeDynamicPng :: FilePath -> DynamicImage -> IO (Either String Bool)
+writeDynamicPng path img = case encodeDynamicPng img of
+        Left err -> return $ Left err
+        Right b  -> Lb.writeFile path b >> return (Right True)
+
+-- | Encode a dynamic image in PNG if possible, supported images are:
+--
+--   * 'ImageY8'
+--
+--   * 'ImageY16'
+--
+--   * 'ImageYA8'
+--
+--   * 'ImageYA16'
+--
+--   * 'ImageRGB8'
+--
+--   * 'ImageRGB16'
+--
+--   * 'ImageRGBA8'
+--
+--   * 'ImageRGBA16'
+--
+encodeDynamicPng :: DynamicImage -> Either String Lb.ByteString
+encodeDynamicPng (ImageRGB8 img) = Right $ encodePng img
+encodeDynamicPng (ImageRGBA8 img) = Right $ encodePng img
+encodeDynamicPng (ImageY8 img) = Right $ encodePng img
+encodeDynamicPng (ImageY16 img) = Right $ encodePng img
+encodeDynamicPng (ImageYA8 img) = Right $ encodePng img
+encodeDynamicPng (ImageYA16 img) = Right $ encodePng img
+encodeDynamicPng (ImageRGB16 img) = Right $ encodePng img
+encodeDynamicPng (ImageRGBA16 img) = Right $ encodePng img
+encodeDynamicPng _ = Left "Unsupported image format for PNG export"
+ src/Codec/Picture/Png/Internal/Metadata.hs view
@@ -0,0 +1,167 @@+{-# LANGUAGE CPP #-}
+{-# LANGUAGE GADTs #-}
+{-# LANGUAGE OverloadedStrings #-}
+module Codec.Picture.Png.Internal.Metadata( extractMetadatas
+                                 , encodeMetadatas
+                                 ) where
+
+#if !MIN_VERSION_base(4,8,0)
+import Control.Applicative( (<$>), (<*>), pure )
+import Data.Monoid( Monoid, mempty )
+import Data.Foldable( foldMap )
+#endif
+
+import Data.Maybe( fromMaybe )
+import Data.Binary( Binary( get, put ), encode )
+import Data.Binary.Get( getLazyByteStringNul, getWord8 )
+import Data.Binary.Put( putLazyByteString, putWord8 )
+import qualified Data.ByteString.Lazy.Char8 as L
+#if !MIN_VERSION_base(4,11,0)
+import Data.Monoid( (<>) )
+#endif
+
+import qualified Codec.Compression.Zlib as Z
+
+import Codec.Picture.InternalHelper
+import qualified Codec.Picture.Metadata as Met
+import Codec.Picture.Metadata ( Metadatas
+                              , dotsPerMeterToDotPerInch
+                              , Elem( (:=>) ) )
+import Codec.Picture.Png.Internal.Type
+
+#if !MIN_VERSION_base(4,7,0)
+eitherFoldMap :: Monoid m => (a -> m) -> Either e a -> m
+eitherFoldMap f v = case v of
+  Left _ -> mempty
+  Right a -> f a
+#else
+eitherFoldMap :: Monoid m => (a -> m) -> Either e a -> m
+eitherFoldMap = foldMap
+#endif
+
+getGamma :: [L.ByteString] -> Metadatas
+getGamma [] = mempty
+getGamma (g:_) = eitherFoldMap unpackGamma $ runGet get g
+  where
+    unpackGamma gamma = Met.singleton Met.Gamma (getPngGamma gamma)
+
+getDpis :: [L.ByteString] -> Metadatas
+getDpis [] = mempty
+getDpis (b:_) = eitherFoldMap unpackPhys $ runGet get b
+  where
+    unpackPhys PngPhysicalDimension { pngUnit = PngUnitUnknown } =
+      Met.insert Met.DpiX 72 $ Met.singleton Met.DpiY 72
+    unpackPhys phy@PngPhysicalDimension { pngUnit = PngUnitMeter } =
+      Met.insert Met.DpiX dpx $ Met.singleton Met.DpiY dpy
+        where
+          dpx = dotsPerMeterToDotPerInch . fromIntegral $ pngDpiX phy
+          dpy = dotsPerMeterToDotPerInch . fromIntegral $ pngDpiY phy
+
+data PngText = PngText
+  { pngKeyword :: !L.ByteString
+  , pngData    :: !L.ByteString
+  }
+  deriving Show
+
+instance Binary PngText where
+  get = PngText <$> getLazyByteStringNul <*> getRemainingLazyBytes
+  put (PngText kw pdata) = do
+    putLazyByteString kw
+    putWord8 0
+    putLazyByteString pdata
+
+data PngZText = PngZText
+  { pngZKeyword :: !L.ByteString
+  , pngZData    :: !L.ByteString
+  }
+  deriving Show
+
+instance Binary PngZText where
+  get = PngZText <$> getLazyByteStringNul <* getCompressionType <*> (Z.decompress <$> getRemainingLazyBytes)
+    where
+      getCompressionType = do
+        0 <- getWord8
+        return ()
+  put (PngZText kw pdata) = do
+    putLazyByteString kw
+    putWord8 0
+    putWord8 0 -- compression type
+    putLazyByteString (Z.compress pdata)
+
+aToMetadata :: (a -> L.ByteString) -> (a -> L.ByteString) -> a -> Metadatas
+aToMetadata pkeyword pdata ptext = case pkeyword ptext of
+  "Title" -> strValue Met.Title
+  "Author" -> strValue Met.Author
+  "Description" -> strValue Met.Description
+  "Copyright" -> strValue Met.Copyright
+  {-"Creation Time" -> strValue Creation-}
+  "Software" -> strValue Met.Software
+  "Disclaimer" -> strValue Met.Disclaimer
+  "Warning" -> strValue Met.Warning
+  "Source" -> strValue Met.Source
+  "Comment" -> strValue Met.Comment
+  other -> 
+    Met.singleton
+      (Met.Unknown $ L.unpack other)
+      (Met.String . L.unpack $ pdata ptext)
+  where
+    strValue k = Met.singleton k . L.unpack $ pdata ptext
+
+textToMetadata :: PngText -> Metadatas
+textToMetadata = aToMetadata pngKeyword pngData
+
+ztxtToMetadata :: PngZText -> Metadatas
+ztxtToMetadata = aToMetadata pngZKeyword pngZData
+
+getTexts :: [L.ByteString] -> Metadatas
+getTexts = foldMap (eitherFoldMap textToMetadata . runGet get)
+
+getZTexts :: [L.ByteString] -> Metadatas
+getZTexts = foldMap (eitherFoldMap ztxtToMetadata . runGet get)
+
+extractMetadatas :: PngRawImage -> Metadatas
+extractMetadatas img = getDpis (chunksOf pHYsSignature)
+                    <> getGamma (chunksOf gammaSignature)
+                    <> getTexts (chunksOf tEXtSignature)
+                    <> getZTexts (chunksOf zTXtSignature)
+  where
+    chunksOf = chunksWithSig img
+
+encodePhysicalMetadata :: Metadatas -> [PngRawChunk]
+encodePhysicalMetadata metas = fromMaybe [] $ do
+  dx <- Met.lookup Met.DpiX metas
+  dy <- Met.lookup Met.DpiY metas
+  let to = fromIntegral . Met.dotPerInchToDotsPerMeter
+      dim = PngPhysicalDimension (to dx) (to dy) PngUnitMeter
+  pure [mkRawChunk pHYsSignature $ encode dim]
+
+encodeSingleMetadata :: Metadatas -> [PngRawChunk]
+encodeSingleMetadata = Met.foldMap go where
+  go :: Elem Met.Keys -> [PngRawChunk]
+  go v = case v of
+    Met.Exif _ :=> _ -> mempty
+    Met.DpiX :=> _ -> mempty
+    Met.DpiY :=> _ -> mempty
+    Met.Width :=> _ -> mempty
+    Met.Height :=> _ -> mempty
+    Met.Format :=> _ -> mempty
+    Met.Gamma       :=> g ->
+      pure $ mkRawChunk gammaSignature . encode $ PngGamma g
+    Met.ColorSpace  :=> _ -> mempty
+    Met.Title       :=> tx -> txt "Title" (L.pack tx)
+    Met.Description :=> tx -> txt "Description" (L.pack tx)
+    Met.Author      :=> tx -> txt "Author" (L.pack tx)
+    Met.Copyright   :=> tx -> txt "Copyright" (L.pack tx)
+    Met.Software    :=> tx -> txt "Software" (L.pack tx)
+    Met.Comment     :=> tx -> txt "Comment" (L.pack tx)
+    Met.Disclaimer  :=> tx -> txt "Disclaimer" (L.pack tx)
+    Met.Source      :=> tx -> txt "Source" (L.pack tx)
+    Met.Warning     :=> tx -> txt "Warning" (L.pack tx)
+    Met.Unknown k   :=> Met.String tx -> txt (L.pack k) (L.pack tx)
+    Met.Unknown _   :=> _ -> mempty
+
+  txt k c = pure . mkRawChunk tEXtSignature . encode $ PngText k c
+
+encodeMetadatas :: Metadatas -> [PngRawChunk]
+encodeMetadatas m = encodePhysicalMetadata m <> encodeSingleMetadata m
+
+ src/Codec/Picture/Png/Internal/Type.hs view
@@ -0,0 +1,452 @@+{-# LANGUAGE CPP #-}
+-- | Low level png module, you should import 'Codec.Picture.Png.Internal' instead.
+module Codec.Picture.Png.Internal.Type( PngIHdr( .. )
+                             , PngFilter( .. )
+                             , PngInterlaceMethod( .. )
+                             , PngPalette
+                             , PngImageType( .. )
+                             , PngPhysicalDimension( .. )
+                             , PngGamma( .. )
+                             , PngUnit( .. )
+                             , APngAnimationControl( .. )
+                             , APngFrameDisposal( .. )
+                             , APngBlendOp( .. )
+                             , APngFrameControl( .. )
+                             , parsePalette 
+                             , pngComputeCrc
+                             , pngSignature
+                             , iHDRSignature
+                             , pLTESignature
+                             , iDATSignature
+                             , iENDSignature
+                             , tRNSSignature
+                             , tEXtSignature
+                             , zTXtSignature
+                             , gammaSignature
+                             , pHYsSignature
+                             , animationControlSignature
+                             -- * Low level types
+                             , ChunkSignature
+                             , PngRawImage( .. )
+                             , PngChunk( .. )
+                             , PngRawChunk( .. )
+                             , PngLowLevel( .. )
+                             , chunksWithSig
+                             , mkRawChunk
+                             ) where
+
+#if !MIN_VERSION_base(4,8,0)
+import Control.Applicative( (<$>), (<*>), pure )
+#endif
+
+import Control.Monad( when, replicateM )
+import Data.Bits( xor, (.&.), unsafeShiftR )
+import Data.Binary( Binary(..), Get, get )
+import Data.Binary.Get( getWord8
+                      , getWord32be
+                      , getLazyByteString
+                      )
+import Data.Binary.Put( runPut
+                      , putWord8
+                      , putWord32be
+                      , putLazyByteString
+                      )
+import Data.Vector.Unboxed( Vector, fromListN, (!) )
+import qualified Data.Vector.Storable as V
+import Data.List( foldl' )
+import Data.Word( Word32, Word16, Word8 )
+import qualified Data.ByteString.Lazy as L
+import qualified Data.ByteString.Lazy.Char8 as LS
+
+import Codec.Picture.Types
+import Codec.Picture.InternalHelper
+
+--------------------------------------------------
+----            Types
+--------------------------------------------------
+
+-- | Value used to identify a png chunk, must be 4 bytes long.
+type ChunkSignature = L.ByteString
+
+-- | Generic header used in PNG images.
+data PngIHdr = PngIHdr
+    { width             :: !Word32       -- ^ Image width in number of pixel
+    , height            :: !Word32       -- ^ Image height in number of pixel
+    , bitDepth          :: !Word8        -- ^ Number of bit per sample
+    , colourType        :: !PngImageType -- ^ Kind of png image (greyscale, true color, indexed...)
+    , compressionMethod :: !Word8        -- ^ Compression method used
+    , filterMethod      :: !Word8        -- ^ Must be 0
+    , interlaceMethod   :: !PngInterlaceMethod   -- ^ If the image is interlaced (for progressive rendering)
+    }
+    deriving Show
+
+data PngUnit
+    = PngUnitUnknown -- ^ 0 value
+    | PngUnitMeter   -- ^ 1 value
+
+instance Binary PngUnit where
+  get = do
+    v <- getWord8
+    pure $ case v of
+      0 -> PngUnitUnknown
+      1 -> PngUnitMeter
+      _ -> PngUnitUnknown
+  
+  put v = case v of
+    PngUnitUnknown -> putWord8 0
+    PngUnitMeter -> putWord8 1
+
+data PngPhysicalDimension = PngPhysicalDimension
+    { pngDpiX     :: !Word32
+    , pngDpiY     :: !Word32
+    , pngUnit     :: !PngUnit
+    }
+
+instance Binary PngPhysicalDimension where
+  get = PngPhysicalDimension <$> getWord32be <*> getWord32be <*> get
+  put (PngPhysicalDimension dpx dpy unit) =
+    putWord32be dpx >> putWord32be dpy >> put unit
+
+newtype PngGamma = PngGamma { getPngGamma :: Double }
+
+instance Binary PngGamma where
+  get = PngGamma . (/ 100000) . fromIntegral <$> getWord32be
+  put = putWord32be . ceiling . (100000 *) . getPngGamma 
+
+data APngAnimationControl = APngAnimationControl
+    { animationFrameCount :: !Word32
+    , animationPlayCount  :: !Word32
+    }
+    deriving Show
+
+-- | Encoded in a Word8
+data APngFrameDisposal
+      -- | No disposal is done on this frame before rendering the
+      -- next; the contents of the output buffer are left as is. 
+      -- Has Value 0
+    = APngDisposeNone
+      -- | The frame's region of the output buffer is to be cleared
+      -- to fully transparent black before rendering the next frame. 
+      -- Has Value 1
+    | APngDisposeBackground
+      -- | the frame's region of the output buffer is to be reverted
+      -- to the previous contents before rendering the next frame.
+      -- Has Value 2
+    | APngDisposePrevious 
+    deriving Show
+
+-- | Encoded in a Word8
+data APngBlendOp
+      -- | Overwrite output buffer. has value '0'
+    = APngBlendSource
+      -- | Alpha blend to the output buffer. Has value '1'
+    | APngBlendOver
+    deriving Show
+
+data APngFrameControl = APngFrameControl
+    { frameSequenceNum      :: !Word32 -- ^ Starting from 0
+    , frameWidth            :: !Word32 -- ^ Width of the following frame
+    , frameHeight           :: !Word32 -- ^ Height of the following frame
+    , frameLeft             :: !Word32 -- X position where to render the frame.
+    , frameTop              :: !Word32 -- Y position where to render the frame.
+    , frameDelayNumerator   :: !Word16
+    , frameDelayDenuminator :: !Word16
+    , frameDisposal         :: !APngFrameDisposal
+    , frameBlending         :: !APngBlendOp
+    }
+    deriving Show
+
+-- | What kind of information is encoded in the IDAT section
+-- of the PngFile
+data PngImageType =
+      PngGreyscale
+    | PngTrueColour
+    | PngIndexedColor
+    | PngGreyscaleWithAlpha
+    | PngTrueColourWithAlpha
+    deriving Show
+
+-- | Raw parsed image which need to be decoded.
+data PngRawImage = PngRawImage
+    { header       :: PngIHdr
+    , chunks       :: [PngRawChunk]
+    }
+
+-- | Palette with indices beginning at 0 to elemcount - 1
+type PngPalette = Palette' PixelRGB8
+
+-- | Parse a palette from a png chunk.
+parsePalette :: PngRawChunk -> Either String PngPalette
+parsePalette plte
+ | chunkLength plte `mod` 3 /= 0 = Left "Invalid palette size"
+ | otherwise = Palette' pixelCount . V.fromListN (3 * pixelCount) <$> pixels
+    where pixelUnpacker = replicateM (fromIntegral pixelCount * 3) get
+          pixelCount = fromIntegral $ chunkLength plte `div` 3
+          pixels = runGet pixelUnpacker (chunkData plte)
+
+-- | Data structure during real png loading/parsing
+data PngRawChunk = PngRawChunk
+    { chunkLength :: Word32
+    , chunkType   :: ChunkSignature
+    , chunkCRC    :: Word32
+    , chunkData   :: L.ByteString
+    }
+
+mkRawChunk :: ChunkSignature -> L.ByteString -> PngRawChunk
+mkRawChunk sig binaryData = PngRawChunk
+  { chunkLength = fromIntegral $ L.length binaryData
+  , chunkType   = sig
+  , chunkCRC    = pngComputeCrc [sig, binaryData]
+  , chunkData   = binaryData
+  }
+
+-- | PNG chunk representing some extra information found in the parsed file.
+data PngChunk = PngChunk
+    { pngChunkData        :: L.ByteString  -- ^ The raw data inside the chunk
+    , pngChunkSignature   :: ChunkSignature -- ^ The name of the chunk.
+    }
+
+-- | Low level access to PNG information
+data PngLowLevel a = PngLowLevel
+    { pngImage  :: Image a      -- ^ The real uncompressed image
+    , pngChunks :: [PngChunk]   -- ^ List of raw chunk where some user data might be present.
+    }
+
+-- | The pixels value should be :
+-- +---+---+
+-- | c | b |
+-- +---+---+
+-- | a | x |
+-- +---+---+
+-- x being the current filtered pixel
+data PngFilter =
+    -- | Filt(x) = Orig(x), Recon(x) = Filt(x)
+      FilterNone
+    -- | Filt(x) = Orig(x) - Orig(a),     Recon(x) = Filt(x) + Recon(a)
+    | FilterSub
+    -- | Filt(x) = Orig(x) - Orig(b),     Recon(x) = Filt(x) + Recon(b)
+    | FilterUp
+    -- | Filt(x) = Orig(x) - floor((Orig(a) + Orig(b)) / 2),
+    -- Recon(x) = Filt(x) + floor((Recon(a) + Recon(b)) / 2)
+    | FilterAverage
+    -- | Filt(x) = Orig(x) - PaethPredictor(Orig(a), Orig(b), Orig(c)),
+    -- Recon(x) = Filt(x) + PaethPredictor(Recon(a), Recon(b), Recon(c))
+    | FilterPaeth
+    deriving (Enum, Show)
+
+-- | Different known interlace methods for PNG image
+data PngInterlaceMethod =
+      -- | No interlacing, basic data ordering, line by line
+      -- from left to right.
+      PngNoInterlace
+
+      -- | Use the Adam7 ordering, see `adam7Reordering`
+    | PngInterlaceAdam7
+    deriving (Enum, Show)
+
+--------------------------------------------------
+----            Instances
+--------------------------------------------------
+instance Binary PngFilter where
+    put = putWord8 . toEnum . fromEnum
+    get = getWord8 >>= \w -> case w of
+        0 -> return FilterNone
+        1 -> return FilterSub
+        2 -> return FilterUp
+        3 -> return FilterAverage
+        4 -> return FilterPaeth
+        _ -> fail "Invalid scanline filter"
+
+instance Binary PngRawImage where
+    put img = do
+        putLazyByteString pngSignature
+        put $ header img
+        mapM_ put $ chunks img
+
+    get = parseRawPngImage
+
+instance Binary PngRawChunk where
+    put chunk = do
+        putWord32be $ chunkLength chunk
+        putLazyByteString $ chunkType chunk
+        when (chunkLength chunk /= 0)
+             (putLazyByteString $ chunkData chunk)
+        putWord32be $ chunkCRC chunk
+
+    get = do
+        size <- getWord32be
+        chunkSig <- getLazyByteString (fromIntegral $ L.length iHDRSignature)
+        imgData <- if size == 0
+            then return L.empty
+            else getLazyByteString (fromIntegral size)
+        crc <- getWord32be
+
+        let computedCrc = pngComputeCrc [chunkSig, imgData]
+        when (computedCrc `xor` crc /= 0)
+             (fail $ "Invalid CRC : " ++ show computedCrc ++ ", "
+                                      ++ show crc)
+        return PngRawChunk {
+            chunkLength = size,
+            chunkData = imgData,
+            chunkCRC = crc,
+            chunkType = chunkSig
+        }
+
+instance Binary PngIHdr where
+    put hdr = do
+        putWord32be 13
+        let inner = runPut $ do
+                putLazyByteString iHDRSignature
+                putWord32be $ width hdr
+                putWord32be $ height hdr
+                putWord8    $ bitDepth hdr
+                put $ colourType hdr
+                put $ compressionMethod hdr
+                put $ filterMethod hdr
+                put $ interlaceMethod hdr
+            crc = pngComputeCrc [inner]
+        putLazyByteString inner
+        putWord32be crc
+
+    get = do
+        _size <- getWord32be
+        ihdrSig <- getLazyByteString (L.length iHDRSignature)
+        when (ihdrSig /= iHDRSignature)
+             (fail "Invalid PNG file, wrong ihdr")
+        w <- getWord32be
+        h <- getWord32be
+        depth <- get
+        colorType <- get
+        compression <- get
+        filtermethod <- get
+        interlace <- get
+        _crc <- getWord32be
+        return PngIHdr {
+            width = w,
+            height = h,
+            bitDepth = depth,
+            colourType = colorType,
+            compressionMethod = compression,
+            filterMethod = filtermethod,
+            interlaceMethod = interlace
+        }
+
+-- | Parse method for a png chunk, without decompression.
+parseChunks :: Get [PngRawChunk]
+parseChunks = do
+    chunk <- get
+
+    if chunkType chunk == iENDSignature
+       then return [chunk]
+       else (chunk:) <$> parseChunks
+
+
+instance Binary PngInterlaceMethod where
+    get = getWord8 >>= \w -> case w of
+        0 -> return PngNoInterlace
+        1 -> return PngInterlaceAdam7
+        _ -> fail "Invalid interlace method"
+
+    put PngNoInterlace    = putWord8 0
+    put PngInterlaceAdam7 = putWord8 1
+
+-- | Implementation of the get method for the PngRawImage,
+-- unpack raw data, without decompressing it.
+parseRawPngImage :: Get PngRawImage
+parseRawPngImage = do
+    sig <- getLazyByteString (L.length pngSignature)
+    when (sig /= pngSignature)
+         (fail "Invalid PNG file, signature broken")
+
+    ihdr <- get
+
+    chunkList <- parseChunks
+    return PngRawImage { header = ihdr, chunks = chunkList }
+
+--------------------------------------------------
+----            functions
+--------------------------------------------------
+
+-- | Signature signalling that the following data will be a png image
+-- in the png bit stream
+pngSignature :: ChunkSignature
+pngSignature = L.pack [137, 80, 78, 71, 13, 10, 26, 10]
+
+-- | Helper function to help pack signatures.
+signature :: String -> ChunkSignature
+signature = LS.pack 
+
+-- | Signature for the header chunk of png (must be the first)
+iHDRSignature :: ChunkSignature 
+iHDRSignature = signature "IHDR"
+
+-- | Signature for a palette chunk in the pgn file. Must
+-- occure before iDAT.
+pLTESignature :: ChunkSignature
+pLTESignature = signature "PLTE"
+
+-- | Signature for a data chuck (with image parts in it)
+iDATSignature :: ChunkSignature
+iDATSignature = signature "IDAT"
+
+-- | Signature for the last chunk of a png image, telling
+-- the end.
+iENDSignature :: ChunkSignature
+iENDSignature = signature "IEND"
+
+tRNSSignature :: ChunkSignature
+tRNSSignature = signature "tRNS"
+
+gammaSignature :: ChunkSignature
+gammaSignature = signature "gAMA"
+
+pHYsSignature :: ChunkSignature
+pHYsSignature = signature "pHYs"
+
+tEXtSignature :: ChunkSignature
+tEXtSignature = signature "tEXt"
+
+zTXtSignature :: ChunkSignature
+zTXtSignature = signature "zTXt"
+
+animationControlSignature :: ChunkSignature
+animationControlSignature = signature "acTL"
+
+instance Binary PngImageType where
+    put PngGreyscale = putWord8 0
+    put PngTrueColour = putWord8 2
+    put PngIndexedColor = putWord8 3
+    put PngGreyscaleWithAlpha = putWord8 4
+    put PngTrueColourWithAlpha = putWord8 6
+
+    get = get >>= imageTypeOfCode
+
+imageTypeOfCode :: Word8 -> Get PngImageType
+imageTypeOfCode 0 = return PngGreyscale
+imageTypeOfCode 2 = return PngTrueColour
+imageTypeOfCode 3 = return PngIndexedColor
+imageTypeOfCode 4 = return PngGreyscaleWithAlpha
+imageTypeOfCode 6 = return PngTrueColourWithAlpha
+imageTypeOfCode _ = fail "Invalid png color code"
+
+-- | From the Annex D of the png specification.
+pngCrcTable :: Vector Word32
+pngCrcTable = fromListN 256 [ foldl' updateCrcConstant c [zero .. 7] | c <- [0 .. 255] ]
+    where zero = 0 :: Int -- To avoid defaulting to Integer
+          updateCrcConstant c _ | c .&. 1 /= 0 = magicConstant `xor` (c `unsafeShiftR` 1)
+                                | otherwise = c `unsafeShiftR` 1
+          magicConstant = 0xedb88320 :: Word32
+
+-- | Compute the CRC of a raw buffer, as described in annex D of the PNG
+-- specification.
+pngComputeCrc :: [L.ByteString] -> Word32
+pngComputeCrc = (0xFFFFFFFF `xor`) . L.foldl' updateCrc 0xFFFFFFFF . L.concat
+    where updateCrc crc val =
+              let u32Val = fromIntegral val
+                  lutVal = pngCrcTable ! (fromIntegral ((crc `xor` u32Val) .&. 0xFF))
+              in lutVal `xor` (crc `unsafeShiftR` 8)
+
+chunksWithSig :: PngRawImage -> ChunkSignature -> [LS.ByteString]
+chunksWithSig rawImg sig =
+  [chunkData chunk | chunk <- chunks rawImg, chunkType chunk == sig]
+
− src/Codec/Picture/Png/Metadata.hs
@@ -1,135 +0,0 @@-{-# LANGUAGE CPP #-}-{-# LANGUAGE GADTs #-}-{-# LANGUAGE OverloadedStrings #-}-module Codec.Picture.Png.Metadata( extractMetadatas-                                 , encodeMetadatas-                                 ) where--#if !MIN_VERSION_base(4,8,0)-import Control.Applicative( (<$>), (<*>), pure )-import Data.Monoid( Monoid, mempty )-import Data.Foldable( foldMap )-#endif--import Data.Maybe( fromMaybe )-import Data.Binary( Binary( get, put ), encode )-import Data.Binary.Get( getLazyByteStringNul )-import Data.Binary.Put( putLazyByteString, putWord8 )-import qualified Data.ByteString.Lazy.Char8 as L-import Data.Monoid( (<>) )--import Codec.Picture.InternalHelper-import qualified Codec.Picture.Metadata as Met-import Codec.Picture.Metadata ( Metadatas-                              , dotsPerMeterToDotPerInch-                              , Elem( (:=>) ) )-import Codec.Picture.Png.Type--#if !MIN_VERSION_base(4,7,0)-eitherFoldMap :: Monoid m => (a -> m) -> Either e a -> m-eitherFoldMap f v = case v of-  Left _ -> mempty-  Right a -> f a-#else-eitherFoldMap :: Monoid m => (a -> m) -> Either e a -> m-eitherFoldMap = foldMap-#endif--getGamma :: [L.ByteString] -> Metadatas-getGamma [] = mempty-getGamma (g:_) = eitherFoldMap unpackGamma $ runGet get g-  where-    unpackGamma gamma = Met.singleton Met.Gamma (getPngGamma gamma)--getDpis :: [L.ByteString] -> Metadatas-getDpis [] = mempty-getDpis (b:_) = eitherFoldMap unpackPhys $ runGet get b-  where-    unpackPhys PngPhysicalDimension { pngUnit = PngUnitUnknown } =-      Met.insert Met.DpiX 72 $ Met.singleton Met.DpiY 72-    unpackPhys phy@PngPhysicalDimension { pngUnit = PngUnitMeter } =-      Met.insert Met.DpiX dpx $ Met.singleton Met.DpiY dpy-        where-          dpx = dotsPerMeterToDotPerInch . fromIntegral $ pngDpiX phy-          dpy = dotsPerMeterToDotPerInch . fromIntegral $ pngDpiY phy--data PngText = PngText-  { pngKeyword :: !L.ByteString-  , pngData    :: !L.ByteString-  }-  deriving Show--instance Binary PngText where-  get = PngText <$> getLazyByteStringNul <*> getRemainingLazyBytes-  put (PngText kw pdata) = do-    putLazyByteString kw-    putWord8 0-    putLazyByteString pdata--textToMetadata :: PngText -> Metadatas-textToMetadata ptext = case pngKeyword ptext of-  "Title" -> strValue Met.Title-  "Author" -> strValue Met.Author-  "Description" -> strValue Met.Description-  "Copyright" -> strValue Met.Copyright-  {-"Creation Time" -> strValue Creation-}-  "Software" -> strValue Met.Software-  "Disclaimer" -> strValue Met.Disclaimer-  "Warning" -> strValue Met.Warning-  "Source" -> strValue Met.Source-  "Comment" -> strValue Met.Comment-  other -> -    Met.singleton-      (Met.Unknown $ L.unpack other)-      (Met.String . L.unpack $ pngData ptext)-  where-    strValue k = Met.singleton k . L.unpack $ pngData ptext--getTexts :: [L.ByteString] -> Metadatas-getTexts = foldMap (eitherFoldMap textToMetadata . runGet get) where- --extractMetadatas :: PngRawImage -> Metadatas-extractMetadatas img = getDpis (chunksOf pHYsSignature)-                    <> getGamma (chunksOf gammaSignature)-                    <> getTexts (chunksOf tEXtSignature)-  where-    chunksOf = chunksWithSig img--encodePhysicalMetadata :: Metadatas -> [PngRawChunk]-encodePhysicalMetadata metas = fromMaybe [] $ do-  dx <- Met.lookup Met.DpiX metas-  dy <- Met.lookup Met.DpiY metas-  let to = fromIntegral . Met.dotPerInchToDotsPerMeter-      dim = PngPhysicalDimension (to dx) (to dy) PngUnitMeter-  pure [mkRawChunk pHYsSignature $ encode dim]--encodeSingleMetadata :: Metadatas -> [PngRawChunk]-encodeSingleMetadata = Met.foldMap go where-  go :: Elem Met.Keys -> [PngRawChunk]-  go v = case v of-    Met.Exif _ :=> _ -> mempty-    Met.DpiX :=> _ -> mempty-    Met.DpiY :=> _ -> mempty-    Met.Width :=> _ -> mempty-    Met.Height :=> _ -> mempty-    Met.Format :=> _ -> mempty-    Met.Gamma       :=> g ->-      pure $ mkRawChunk gammaSignature . encode $ PngGamma g-    Met.Title       :=> tx -> txt "Title" (L.pack tx)-    Met.Description :=> tx -> txt "Description" (L.pack tx)-    Met.Author      :=> tx -> txt "Author" (L.pack tx)-    Met.Copyright   :=> tx -> txt "Copyright" (L.pack tx)-    Met.Software    :=> tx -> txt "Software" (L.pack tx)-    Met.Comment     :=> tx -> txt "Comment" (L.pack tx)-    Met.Disclaimer  :=> tx -> txt "Disclaimer" (L.pack tx)-    Met.Source      :=> tx -> txt "Source" (L.pack tx)-    Met.Warning     :=> tx -> txt "Warning" (L.pack tx)-    Met.Unknown k   :=> Met.String tx -> txt (L.pack k) (L.pack tx)-    Met.Unknown _   :=> _ -> mempty--  txt k c = pure . mkRawChunk tEXtSignature . encode $ PngText k c--encodeMetadatas :: Metadatas -> [PngRawChunk]-encodeMetadatas m = encodePhysicalMetadata m <> encodeSingleMetadata m-
− src/Codec/Picture/Png/Type.hs
@@ -1,450 +0,0 @@-{-# LANGUAGE CPP #-}
--- | Low level png module, you should import 'Codec.Picture.Png' instead.
-module Codec.Picture.Png.Type( PngIHdr( .. )
-                             , PngFilter( .. )
-                             , PngInterlaceMethod( .. )
-                             , PngPalette
-                             , PngImageType( .. )
-                             , PngPhysicalDimension( .. )
-                             , PngGamma( .. )
-                             , PngUnit( .. )
-                             , APngAnimationControl( .. )
-                             , APngFrameDisposal( .. )
-                             , APngBlendOp( .. )
-                             , APngFrameControl( .. )
-                             , parsePalette 
-                             , pngComputeCrc
-                             , pLTESignature
-                             , iDATSignature
-                             , iENDSignature
-                             , tRNSSignature
-                             , tEXtSignature
-                             , zTXtSignature
-                             , gammaSignature
-                             , pHYsSignature
-                             , animationControlSignature
-                             -- * Low level types
-                             , ChunkSignature
-                             , PngRawImage( .. )
-                             , PngChunk( .. )
-                             , PngRawChunk( .. )
-                             , PngLowLevel( .. )
-                             , chunksWithSig
-                             , mkRawChunk
-                             ) where
-
-#if !MIN_VERSION_base(4,8,0)
-import Control.Applicative( (<$>), (<*>), pure )
-#endif
-
-import Control.Monad( when, replicateM )
-import Data.Bits( xor, (.&.), unsafeShiftR )
-import Data.Binary( Binary(..), Get, get )
-import Data.Binary.Get( getWord8
-                      , getWord32be
-                      , getLazyByteString
-                      )
-import Data.Binary.Put( runPut
-                      , putWord8
-                      , putWord32be
-                      , putLazyByteString
-                      )
-import Data.Vector.Unboxed( Vector, fromListN, (!) )
-import qualified Data.Vector.Storable as V
-import Data.List( foldl' )
-import Data.Word( Word32, Word16, Word8 )
-import qualified Data.ByteString.Lazy as L
-import qualified Data.ByteString.Lazy.Char8 as LS
-
-import Codec.Picture.Types
-import Codec.Picture.InternalHelper
-
---------------------------------------------------
-----            Types
---------------------------------------------------
-
--- | Value used to identify a png chunk, must be 4 bytes long.
-type ChunkSignature = L.ByteString
-
--- | Generic header used in PNG images.
-data PngIHdr = PngIHdr
-    { width             :: !Word32       -- ^ Image width in number of pixel
-    , height            :: !Word32       -- ^ Image height in number of pixel
-    , bitDepth          :: !Word8        -- ^ Number of bit per sample
-    , colourType        :: !PngImageType -- ^ Kind of png image (greyscale, true color, indexed...)
-    , compressionMethod :: !Word8        -- ^ Compression method used
-    , filterMethod      :: !Word8        -- ^ Must be 0
-    , interlaceMethod   :: !PngInterlaceMethod   -- ^ If the image is interlaced (for progressive rendering)
-    }
-    deriving Show
-
-data PngUnit
-    = PngUnitUnknown -- ^ 0 value
-    | PngUnitMeter   -- ^ 1 value
-
-instance Binary PngUnit where
-  get = do
-    v <- getWord8
-    pure $ case v of
-      0 -> PngUnitUnknown
-      1 -> PngUnitMeter
-      _ -> PngUnitUnknown
-  
-  put v = case v of
-    PngUnitUnknown -> putWord8 0
-    PngUnitMeter -> putWord8 1
-
-data PngPhysicalDimension = PngPhysicalDimension
-    { pngDpiX     :: !Word32
-    , pngDpiY     :: !Word32
-    , pngUnit     :: !PngUnit
-    }
-
-instance Binary PngPhysicalDimension where
-  get = PngPhysicalDimension <$> getWord32be <*> getWord32be <*> get
-  put (PngPhysicalDimension dpx dpy unit) =
-    putWord32be dpx >> putWord32be dpy >> put unit
-
-newtype PngGamma = PngGamma { getPngGamma :: Double }
-
-instance Binary PngGamma where
-  get = PngGamma . (/ 100000) . fromIntegral <$> getWord32be
-  put = putWord32be . ceiling . (100000 *) . getPngGamma 
-
-data APngAnimationControl = APngAnimationControl
-    { animationFrameCount :: !Word32
-    , animationPlayCount  :: !Word32
-    }
-    deriving Show
-
--- | Encoded in a Word8
-data APngFrameDisposal
-      -- | No disposal is done on this frame before rendering the
-      -- next; the contents of the output buffer are left as is. 
-      -- Has Value 0
-    = APngDisposeNone
-      -- | The frame's region of the output buffer is to be cleared
-      -- to fully transparent black before rendering the next frame. 
-      -- Has Value 1
-    | APngDisposeBackground
-      -- | the frame's region of the output buffer is to be reverted
-      -- to the previous contents before rendering the next frame.
-      -- Has Value 2
-    | APngDisposePrevious 
-    deriving Show
-
--- | Encoded in a Word8
-data APngBlendOp
-      -- | Overwrite output buffer. has value '0'
-    = APngBlendSource
-      -- | Alpha blend to the output buffer. Has value '1'
-    | APngBlendOver
-    deriving Show
-
-data APngFrameControl = APngFrameControl
-    { frameSequenceNum      :: !Word32 -- ^ Starting from 0
-    , frameWidth            :: !Word32 -- ^ Width of the following frame
-    , frameHeight           :: !Word32 -- ^ Height of the following frame
-    , frameLeft             :: !Word32 -- X position where to render the frame.
-    , frameTop              :: !Word32 -- Y position where to render the frame.
-    , frameDelayNumerator   :: !Word16
-    , frameDelayDenuminator :: !Word16
-    , frameDisposal         :: !APngFrameDisposal
-    , frameBlending         :: !APngBlendOp
-    }
-    deriving Show
-
--- | What kind of information is encoded in the IDAT section
--- of the PngFile
-data PngImageType =
-      PngGreyscale
-    | PngTrueColour
-    | PngIndexedColor
-    | PngGreyscaleWithAlpha
-    | PngTrueColourWithAlpha
-    deriving Show
-
--- | Raw parsed image which need to be decoded.
-data PngRawImage = PngRawImage
-    { header       :: PngIHdr
-    , chunks       :: [PngRawChunk]
-    }
-
--- | Palette with indices beginning at 0 to elemcount - 1
-type PngPalette = Palette' PixelRGB8
-
--- | Parse a palette from a png chunk.
-parsePalette :: PngRawChunk -> Either String PngPalette
-parsePalette plte
- | chunkLength plte `mod` 3 /= 0 = Left "Invalid palette size"
- | otherwise = Palette' pixelCount . V.fromListN (3 * pixelCount) <$> pixels
-    where pixelUnpacker = replicateM (fromIntegral pixelCount * 3) get
-          pixelCount = fromIntegral $ chunkLength plte `div` 3
-          pixels = runGet pixelUnpacker (chunkData plte)
-
--- | Data structure during real png loading/parsing
-data PngRawChunk = PngRawChunk
-    { chunkLength :: Word32
-    , chunkType   :: ChunkSignature
-    , chunkCRC    :: Word32
-    , chunkData   :: L.ByteString
-    }
-
-mkRawChunk :: ChunkSignature -> L.ByteString -> PngRawChunk
-mkRawChunk sig binaryData = PngRawChunk
-  { chunkLength = fromIntegral $ L.length binaryData
-  , chunkType   = sig
-  , chunkCRC    = pngComputeCrc [sig, binaryData]
-  , chunkData   = binaryData
-  }
-
--- | PNG chunk representing some extra information found in the parsed file.
-data PngChunk = PngChunk
-    { pngChunkData        :: L.ByteString  -- ^ The raw data inside the chunk
-    , pngChunkSignature   :: ChunkSignature -- ^ The name of the chunk.
-    }
-
--- | Low level access to PNG information
-data PngLowLevel a = PngLowLevel
-    { pngImage  :: Image a      -- ^ The real uncompressed image
-    , pngChunks :: [PngChunk]   -- ^ List of raw chunk where some user data might be present.
-    }
-
--- | The pixels value should be :
--- +---+---+
--- | c | b |
--- +---+---+
--- | a | x |
--- +---+---+
--- x being the current filtered pixel
-data PngFilter =
-    -- | Filt(x) = Orig(x), Recon(x) = Filt(x)
-      FilterNone
-    -- | Filt(x) = Orig(x) - Orig(a),     Recon(x) = Filt(x) + Recon(a)
-    | FilterSub
-    -- | Filt(x) = Orig(x) - Orig(b),     Recon(x) = Filt(x) + Recon(b)
-    | FilterUp
-    -- | Filt(x) = Orig(x) - floor((Orig(a) + Orig(b)) / 2),
-    -- Recon(x) = Filt(x) + floor((Recon(a) + Recon(b)) / 2)
-    | FilterAverage
-    -- | Filt(x) = Orig(x) - PaethPredictor(Orig(a), Orig(b), Orig(c)),
-    -- Recon(x) = Filt(x) + PaethPredictor(Recon(a), Recon(b), Recon(c))
-    | FilterPaeth
-    deriving (Enum, Show)
-
--- | Different known interlace methods for PNG image
-data PngInterlaceMethod =
-      -- | No interlacing, basic data ordering, line by line
-      -- from left to right.
-      PngNoInterlace
-
-      -- | Use the Adam7 ordering, see `adam7Reordering`
-    | PngInterlaceAdam7
-    deriving (Enum, Show)
-
---------------------------------------------------
-----            Instances
---------------------------------------------------
-instance Binary PngFilter where
-    put = putWord8 . toEnum . fromEnum
-    get = getWord8 >>= \w -> case w of
-        0 -> return FilterNone
-        1 -> return FilterSub
-        2 -> return FilterUp
-        3 -> return FilterAverage
-        4 -> return FilterPaeth
-        _ -> fail "Invalid scanline filter"
-
-instance Binary PngRawImage where
-    put img = do
-        putLazyByteString pngSignature
-        put $ header img
-        mapM_ put $ chunks img
-
-    get = parseRawPngImage
-
-instance Binary PngRawChunk where
-    put chunk = do
-        putWord32be $ chunkLength chunk
-        putLazyByteString $ chunkType chunk
-        when (chunkLength chunk /= 0)
-             (putLazyByteString $ chunkData chunk)
-        putWord32be $ chunkCRC chunk
-
-    get = do
-        size <- getWord32be
-        chunkSig <- getLazyByteString (fromIntegral $ L.length iHDRSignature)
-        imgData <- if size == 0
-            then return L.empty
-            else getLazyByteString (fromIntegral size)
-        crc <- getWord32be
-
-        let computedCrc = pngComputeCrc [chunkSig, imgData]
-        when (computedCrc `xor` crc /= 0)
-             (fail $ "Invalid CRC : " ++ show computedCrc ++ ", "
-                                      ++ show crc)
-        return PngRawChunk {
-            chunkLength = size,
-            chunkData = imgData,
-            chunkCRC = crc,
-            chunkType = chunkSig
-        }
-
-instance Binary PngIHdr where
-    put hdr = do
-        putWord32be 13
-        let inner = runPut $ do
-                putLazyByteString iHDRSignature
-                putWord32be $ width hdr
-                putWord32be $ height hdr
-                putWord8    $ bitDepth hdr
-                put $ colourType hdr
-                put $ compressionMethod hdr
-                put $ filterMethod hdr
-                put $ interlaceMethod hdr
-            crc = pngComputeCrc [inner]
-        putLazyByteString inner
-        putWord32be crc
-
-    get = do
-        _size <- getWord32be
-        ihdrSig <- getLazyByteString (L.length iHDRSignature)
-        when (ihdrSig /= iHDRSignature)
-             (fail "Invalid PNG file, wrong ihdr")
-        w <- getWord32be
-        h <- getWord32be
-        depth <- get
-        colorType <- get
-        compression <- get
-        filtermethod <- get
-        interlace <- get
-        _crc <- getWord32be
-        return PngIHdr {
-            width = w,
-            height = h,
-            bitDepth = depth,
-            colourType = colorType,
-            compressionMethod = compression,
-            filterMethod = filtermethod,
-            interlaceMethod = interlace
-        }
-
--- | Parse method for a png chunk, without decompression.
-parseChunks :: Get [PngRawChunk]
-parseChunks = do
-    chunk <- get
-
-    if chunkType chunk == iENDSignature
-       then return [chunk]
-       else (chunk:) <$> parseChunks
-
-
-instance Binary PngInterlaceMethod where
-    get = getWord8 >>= \w -> case w of
-        0 -> return PngNoInterlace
-        1 -> return PngInterlaceAdam7
-        _ -> fail "Invalid interlace method"
-
-    put PngNoInterlace    = putWord8 0
-    put PngInterlaceAdam7 = putWord8 1
-
--- | Implementation of the get method for the PngRawImage,
--- unpack raw data, without decompressing it.
-parseRawPngImage :: Get PngRawImage
-parseRawPngImage = do
-    sig <- getLazyByteString (L.length pngSignature)
-    when (sig /= pngSignature)
-         (fail "Invalid PNG file, signature broken")
-
-    ihdr <- get
-
-    chunkList <- parseChunks
-    return PngRawImage { header = ihdr, chunks = chunkList }
-
---------------------------------------------------
-----            functions
---------------------------------------------------
-
--- | Signature signalling that the following data will be a png image
--- in the png bit stream
-pngSignature :: ChunkSignature
-pngSignature = L.pack [137, 80, 78, 71, 13, 10, 26, 10]
-
--- | Helper function to help pack signatures.
-signature :: String -> ChunkSignature
-signature = LS.pack 
-
--- | Signature for the header chunk of png (must be the first)
-iHDRSignature :: ChunkSignature 
-iHDRSignature = signature "IHDR"
-
--- | Signature for a palette chunk in the pgn file. Must
--- occure before iDAT.
-pLTESignature :: ChunkSignature
-pLTESignature = signature "PLTE"
-
--- | Signature for a data chuck (with image parts in it)
-iDATSignature :: ChunkSignature
-iDATSignature = signature "IDAT"
-
--- | Signature for the last chunk of a png image, telling
--- the end.
-iENDSignature :: ChunkSignature
-iENDSignature = signature "IEND"
-
-tRNSSignature :: ChunkSignature
-tRNSSignature = signature "tRNS"
-
-gammaSignature :: ChunkSignature
-gammaSignature = signature "gAMA"
-
-pHYsSignature :: ChunkSignature
-pHYsSignature = signature "pHYs"
-
-tEXtSignature :: ChunkSignature
-tEXtSignature = signature "tEXt"
-
-zTXtSignature :: ChunkSignature
-zTXtSignature = signature "zTXt"
-
-animationControlSignature :: ChunkSignature
-animationControlSignature = signature "acTL"
-
-instance Binary PngImageType where
-    put PngGreyscale = putWord8 0
-    put PngTrueColour = putWord8 2
-    put PngIndexedColor = putWord8 3
-    put PngGreyscaleWithAlpha = putWord8 4
-    put PngTrueColourWithAlpha = putWord8 6
-
-    get = get >>= imageTypeOfCode
-
-imageTypeOfCode :: Word8 -> Get PngImageType
-imageTypeOfCode 0 = return PngGreyscale
-imageTypeOfCode 2 = return PngTrueColour
-imageTypeOfCode 3 = return PngIndexedColor
-imageTypeOfCode 4 = return PngGreyscaleWithAlpha
-imageTypeOfCode 6 = return PngTrueColourWithAlpha
-imageTypeOfCode _ = fail "Invalid png color code"
-
--- | From the Annex D of the png specification.
-pngCrcTable :: Vector Word32
-pngCrcTable = fromListN 256 [ foldl' updateCrcConstant c [zero .. 7] | c <- [0 .. 255] ]
-    where zero = 0 :: Int -- To avoid defaulting to Integer
-          updateCrcConstant c _ | c .&. 1 /= 0 = magicConstant `xor` (c `unsafeShiftR` 1)
-                                | otherwise = c `unsafeShiftR` 1
-          magicConstant = 0xedb88320 :: Word32
-
--- | Compute the CRC of a raw buffer, as described in annex D of the PNG
--- specification.
-pngComputeCrc :: [L.ByteString] -> Word32
-pngComputeCrc = (0xFFFFFFFF `xor`) . L.foldl' updateCrc 0xFFFFFFFF . L.concat
-    where updateCrc crc val =
-              let u32Val = fromIntegral val
-                  lutVal = pngCrcTable ! (fromIntegral ((crc `xor` u32Val) .&. 0xFF))
-              in lutVal `xor` (crc `unsafeShiftR` 8)
-
-chunksWithSig :: PngRawImage -> ChunkSignature -> [LS.ByteString]
-chunksWithSig rawImg sig =
-  [chunkData chunk | chunk <- chunks rawImg, chunkType chunk == sig]
-
src/Codec/Picture/Saving.hs view
@@ -1,214 +1,239 @@-{-# LANGUAGE TypeFamilies #-}-{-# LANGUAGE CPP #-}--- | Helper functions to save dynamic images to other file format--- with automatic color space/sample format conversion done automatically.-module Codec.Picture.Saving( imageToJpg-                           , imageToPng-                           , imageToGif-                           , imageToBitmap-                           , imageToTiff-                           , imageToRadiance-                           , imageToTga-                           ) where--#if !MIN_VERSION_base(4,8,0)-import Data.Monoid( mempty )-#endif--import Data.Bits( unsafeShiftR )-import Data.Word( Word8, Word16 )-import qualified Data.ByteString.Lazy as L-import Codec.Picture.Bitmap-import Codec.Picture.Jpg-import Codec.Picture.Png-import Codec.Picture.Gif-import Codec.Picture.ColorQuant-import Codec.Picture.HDR-import Codec.Picture.Types-import Codec.Picture.Tiff-import Codec.Picture.Tga--import qualified Data.Vector.Storable as V--componentToLDR :: Float -> Word8-componentToLDR = truncate . (255 *) . min 1.0 . max 0.0--toStandardDef :: Image PixelRGBF -> Image PixelRGB8-toStandardDef = pixelMap pixelConverter-  where pixelConverter (PixelRGBF rf gf bf) = PixelRGB8 r g b-          where r = componentToLDR rf-                g = componentToLDR gf-                b = componentToLDR bf--greyScaleToStandardDef :: Image PixelF -> Image Pixel8-greyScaleToStandardDef = pixelMap componentToLDR--from16to8 :: ( PixelBaseComponent source ~ Word16-             , PixelBaseComponent dest ~ Word8 )-          => Image source -> Image dest-from16to8 Image { imageWidth = w, imageHeight = h-                , imageData = arr } = Image w h transformed-   where transformed = V.map toWord8 arr-         toWord8 v = fromIntegral (v `unsafeShiftR` 8)--from16toFloat :: ( PixelBaseComponent source ~ Word16-                 , PixelBaseComponent dest ~ Float )-          => Image source -> Image dest-from16toFloat Image { imageWidth = w, imageHeight = h-                    , imageData = arr } = Image w h transformed-   where transformed = V.map toWord8 arr-         toWord8 v = fromIntegral v / 65536.0---- | This function will try to do anything to encode an image--- as RADIANCE, make all color conversion and such. Equivalent--- of 'decodeImage' for radiance encoding-imageToRadiance :: DynamicImage -> L.ByteString-imageToRadiance (ImageCMYK8 img) =-    imageToRadiance . ImageRGB8 $ convertImage img-imageToRadiance (ImageCMYK16 img) =-    imageToRadiance . ImageRGB16 $ convertImage img-imageToRadiance (ImageYCbCr8 img) =-    imageToRadiance . ImageRGB8 $ convertImage img-imageToRadiance (ImageRGB8   img) =-    imageToRadiance . ImageRGBF $ promoteImage img-imageToRadiance (ImageRGBF   img) = encodeHDR img-imageToRadiance (ImageRGBA8  img) =-    imageToRadiance . ImageRGBF . promoteImage $ dropAlphaLayer img-imageToRadiance (ImageY8     img) =-    imageToRadiance . ImageRGB8 $ promoteImage img-imageToRadiance (ImageYF     img) =-    imageToRadiance . ImageRGBF $ promoteImage img-imageToRadiance (ImageYA8    img) =-    imageToRadiance . ImageRGB8 . promoteImage $ dropAlphaLayer img-imageToRadiance (ImageY16    img) =-  imageToRadiance . ImageRGBF $ pixelMap toRgbf img-    where toRgbf v = PixelRGBF val val val-            where val = fromIntegral v / 65536.0--imageToRadiance (ImageYA16   img) =-  imageToRadiance . ImageRGBF $ pixelMap toRgbf img-    where toRgbf (PixelYA16 v _) = PixelRGBF val val val-            where val = fromIntegral v / 65536.0-imageToRadiance (ImageRGB16  img) =-    imageToRadiance . ImageRGBF $ from16toFloat img-imageToRadiance (ImageRGBA16 img) =-    imageToRadiance . ImageRGBF $ pixelMap toRgbf img-    where toRgbf (PixelRGBA16 r g b _) = PixelRGBF (f r) (f g) (f b)-            where f v = fromIntegral v / 65536.0---- | This function will try to do anything to encode an image--- as JPEG, make all color conversion and such. Equivalent--- of 'decodeImage' for jpeg encoding--- Save Y or YCbCr Jpeg only, all other colorspaces are converted.--- To save a RGB or CMYK JPEG file, use the--- 'Codec.Picture.Jpg.encodeDirectJpegAtQualityWithMetadata' function-imageToJpg :: Int -> DynamicImage -> L.ByteString-imageToJpg quality dynImage =-    let encodeAtQuality = encodeJpegAtQuality (fromIntegral quality)-        encodeWithMeta = encodeDirectJpegAtQualityWithMetadata (fromIntegral quality) mempty-    in case dynImage of-        ImageYCbCr8 img -> encodeAtQuality img-        ImageCMYK8  img -> imageToJpg quality . ImageRGB8 $ convertImage img-        ImageCMYK16 img -> imageToJpg quality . ImageRGB16 $ convertImage img-        ImageRGB8   img -> encodeAtQuality (convertImage img)-        ImageRGBF   img -> imageToJpg quality . ImageRGB8 $ toStandardDef img-        ImageRGBA8  img -> encodeAtQuality (convertImage $ dropAlphaLayer img)-        ImageYF     img -> imageToJpg quality . ImageY8 $ greyScaleToStandardDef img-        ImageY8     img -> encodeWithMeta img-        ImageYA8    img -> encodeWithMeta $ dropAlphaLayer img-        ImageY16    img -> imageToJpg quality . ImageY8 $ from16to8 img-        ImageYA16   img -> imageToJpg quality . ImageYA8 $ from16to8 img-        ImageRGB16  img -> imageToJpg quality . ImageRGB8 $ from16to8 img-        ImageRGBA16 img -> imageToJpg quality . ImageRGBA8 $ from16to8 img---- | This function will try to do anything to encode an image--- as PNG, make all color conversion and such. Equivalent--- of 'decodeImage' for PNG encoding-imageToPng :: DynamicImage -> L.ByteString-imageToPng (ImageYCbCr8 img) = encodePng (convertImage img :: Image PixelRGB8)-imageToPng (ImageCMYK8 img)  = encodePng (convertImage img :: Image PixelRGB8)-imageToPng (ImageCMYK16 img) = encodePng (convertImage img :: Image PixelRGB16)-imageToPng (ImageRGB8   img) = encodePng img-imageToPng (ImageRGBF   img) = encodePng $ toStandardDef img-imageToPng (ImageRGBA8  img) = encodePng img-imageToPng (ImageY8     img) = encodePng img-imageToPng (ImageYF     img) = encodePng $ greyScaleToStandardDef img-imageToPng (ImageYA8    img) = encodePng img-imageToPng (ImageY16    img) = encodePng img-imageToPng (ImageYA16   img) = encodePng img-imageToPng (ImageRGB16  img) = encodePng img-imageToPng (ImageRGBA16 img) = encodePng img---- | This function will try to do anything to encode an image--- as a Tiff, make all color conversion and such. Equivalent--- of 'decodeImage' for Tiff encoding-imageToTiff :: DynamicImage -> L.ByteString-imageToTiff (ImageYCbCr8 img) = encodeTiff img-imageToTiff (ImageCMYK8 img)  = encodeTiff img-imageToTiff (ImageCMYK16 img) = encodeTiff img-imageToTiff (ImageRGB8   img) = encodeTiff img-imageToTiff (ImageRGBF   img) = encodeTiff $ toStandardDef img-imageToTiff (ImageRGBA8  img) = encodeTiff img-imageToTiff (ImageY8     img) = encodeTiff img-imageToTiff (ImageYF     img) = encodeTiff $ greyScaleToStandardDef img-imageToTiff (ImageYA8    img) = encodeTiff $ dropAlphaLayer img-imageToTiff (ImageY16    img) = encodeTiff img-imageToTiff (ImageYA16   img) = encodeTiff $ dropAlphaLayer img-imageToTiff (ImageRGB16  img) = encodeTiff img-imageToTiff (ImageRGBA16 img) = encodeTiff img---- | This function will try to do anything to encode an image--- as bitmap, make all color conversion and such. Equivalent--- of 'decodeImage' for Bitmap encoding-imageToBitmap :: DynamicImage -> L.ByteString-imageToBitmap (ImageYCbCr8 img) = encodeBitmap (convertImage img :: Image PixelRGB8)-imageToBitmap (ImageCMYK8  img) = encodeBitmap (convertImage img :: Image PixelRGB8)-imageToBitmap (ImageCMYK16 img) = imageToBitmap . ImageRGB16 $ convertImage img-imageToBitmap (ImageRGBF   img) = encodeBitmap $ toStandardDef img-imageToBitmap (ImageRGB8   img) = encodeBitmap img-imageToBitmap (ImageRGBA8  img) = encodeBitmap img-imageToBitmap (ImageY8     img) = encodeBitmap img-imageToBitmap (ImageYF     img) = encodeBitmap $ greyScaleToStandardDef img-imageToBitmap (ImageYA8    img) = encodeBitmap (promoteImage img :: Image PixelRGBA8)-imageToBitmap (ImageY16    img) = imageToBitmap . ImageY8 $ from16to8 img-imageToBitmap (ImageYA16   img) = imageToBitmap . ImageYA8 $ from16to8 img-imageToBitmap (ImageRGB16  img) = imageToBitmap . ImageRGB8 $ from16to8 img-imageToBitmap (ImageRGBA16 img) = imageToBitmap . ImageRGBA8 $ from16to8 img----- | This function will try to do anything to encode an image--- as a gif, make all color conversion and quantization. Equivalent--- of 'decodeImage' for gif encoding-imageToGif :: DynamicImage -> Either String L.ByteString-imageToGif (ImageYCbCr8 img) = imageToGif . ImageRGB8 $ convertImage img-imageToGif (ImageCMYK8  img) = imageToGif . ImageRGB8 $ convertImage img-imageToGif (ImageCMYK16 img) = imageToGif . ImageRGB16 $ convertImage img-imageToGif (ImageRGBF   img) = imageToGif . ImageRGB8 $ toStandardDef img-imageToGif (ImageRGB8   img) = encodeGifImageWithPalette indexed pal-  where (indexed, pal) = palettize defaultPaletteOptions img-imageToGif (ImageRGBA8  img) = imageToGif . ImageRGB8 $ dropAlphaLayer img-imageToGif (ImageY8     img) = Right $ encodeGifImage img-imageToGif (ImageYF     img) = imageToGif . ImageY8 $ greyScaleToStandardDef img-imageToGif (ImageYA8    img) = imageToGif . ImageY8 $ dropAlphaLayer img-imageToGif (ImageY16    img) = imageToGif . ImageY8 $ from16to8 img-imageToGif (ImageYA16   img) = imageToGif . ImageYA8 $ from16to8 img-imageToGif (ImageRGB16  img) = imageToGif . ImageRGB8 $ from16to8 img-imageToGif (ImageRGBA16 img) = imageToGif . ImageRGBA8 $ from16to8 img---- | This function will try to do anything to encode an image--- as a tga, make all color conversion and quantization. Equivalent--- of 'decodeImage' for tga encoding-imageToTga :: DynamicImage -> L.ByteString-imageToTga (ImageYCbCr8 img) = encodeTga (convertImage img :: Image PixelRGB8)-imageToTga (ImageCMYK8  img) = encodeTga (convertImage img :: Image PixelRGB8)-imageToTga (ImageCMYK16 img) = encodeTga (from16to8 img :: Image PixelRGB8)-imageToTga (ImageRGBF   img) = encodeTga $ toStandardDef img-imageToTga (ImageRGB8   img) = encodeTga img-imageToTga (ImageRGBA8  img) = encodeTga img-imageToTga (ImageY8     img) = encodeTga img-imageToTga (ImageYF     img) = encodeTga $ greyScaleToStandardDef img-imageToTga (ImageYA8    img) = encodeTga (promoteImage img :: Image PixelRGBA8)-imageToTga (ImageY16    img) = encodeTga (from16to8 img :: Image Pixel8)-imageToTga (ImageYA16   img) = encodeTga (from16to8 img :: Image PixelRGBA8)-imageToTga (ImageRGB16  img) = encodeTga (from16to8 img :: Image PixelRGB8)-imageToTga (ImageRGBA16 img) = encodeTga (from16to8 img :: Image PixelRGBA8)+{-# LANGUAGE TypeFamilies #-}
+{-# LANGUAGE CPP #-}
+-- | Helper functions to save dynamic images to other file format
+-- with automatic color space/sample format conversion done automatically.
+module Codec.Picture.Saving( imageToJpg
+                           , imageToPng
+                           , imageToGif
+                           , imageToBitmap
+                           , imageToTiff
+                           , imageToRadiance
+                           , imageToTga
+                           ) where
+
+#if !MIN_VERSION_base(4,8,0)
+import Data.Monoid( mempty )
+#endif
+
+import Data.Bits( unsafeShiftR )
+import Data.Word( Word8, Word16, Word32 )
+import qualified Data.ByteString.Lazy as L
+import Codec.Picture.Bitmap
+import Codec.Picture.Jpg
+import Codec.Picture.Png
+import Codec.Picture.Gif
+import Codec.Picture.ColorQuant
+import Codec.Picture.HDR
+import Codec.Picture.Types
+import Codec.Picture.Tiff
+import Codec.Picture.Tga
+
+import qualified Data.Vector.Storable as V
+
+componentToLDR :: Float -> Word8
+componentToLDR = truncate . (255 *) . min 1.0 . max 0.0
+
+toStandardDef :: Image PixelRGBF -> Image PixelRGB8
+toStandardDef = pixelMap pixelConverter
+  where pixelConverter (PixelRGBF rf gf bf) = PixelRGB8 r g b
+          where r = componentToLDR rf
+                g = componentToLDR gf
+                b = componentToLDR bf
+
+greyScaleToStandardDef :: Image PixelF -> Image Pixel8
+greyScaleToStandardDef = pixelMap componentToLDR
+
+from16to8 :: ( PixelBaseComponent source ~ Word16
+             , PixelBaseComponent dest ~ Word8 )
+          => Image source -> Image dest
+from16to8 Image { imageWidth = w, imageHeight = h
+                , imageData = arr } = Image w h transformed
+   where transformed = V.map toWord8 arr
+         toWord8 v = fromIntegral (v `unsafeShiftR` 8)
+
+from32to8 :: ( PixelBaseComponent source ~ Word32
+             , PixelBaseComponent dest ~ Word8 )
+          => Image source -> Image dest
+from32to8 Image { imageWidth = w, imageHeight = h
+                , imageData = arr } = Image w h transformed
+   where transformed = V.map toWord8 arr
+         toWord8 v = fromIntegral (v `unsafeShiftR` 24)
+
+from32to16 :: ( PixelBaseComponent source ~ Word32
+             , PixelBaseComponent dest ~ Word16 )
+          => Image source -> Image dest
+from32to16 Image { imageWidth = w, imageHeight = h
+                , imageData = arr } = Image w h transformed
+   where transformed = V.map toWord16 arr
+         toWord16 v = fromIntegral (v `unsafeShiftR` 16)
+
+from16toFloat :: ( PixelBaseComponent source ~ Word16
+                 , PixelBaseComponent dest ~ Float )
+          => Image source -> Image dest
+from16toFloat Image { imageWidth = w, imageHeight = h
+                    , imageData = arr } = Image w h transformed
+   where transformed = V.map toWord8 arr
+         toWord8 v = fromIntegral v / 65536.0
+
+-- | This function will try to do anything to encode an image
+-- as RADIANCE, make all color conversion and such. Equivalent
+-- of 'decodeImage' for radiance encoding
+imageToRadiance :: DynamicImage -> L.ByteString
+imageToRadiance (ImageCMYK8 img) =
+    imageToRadiance . ImageRGB8 $ convertImage img
+imageToRadiance (ImageCMYK16 img) =
+    imageToRadiance . ImageRGB16 $ convertImage img
+imageToRadiance (ImageYCbCr8 img) =
+    imageToRadiance . ImageRGB8 $ convertImage img
+imageToRadiance (ImageRGB8   img) =
+    imageToRadiance . ImageRGBF $ promoteImage img
+imageToRadiance (ImageRGBF   img) = encodeHDR img
+imageToRadiance (ImageRGBA8  img) =
+    imageToRadiance . ImageRGBF . promoteImage $ dropAlphaLayer img
+imageToRadiance (ImageY8     img) =
+    imageToRadiance . ImageRGB8 $ promoteImage img
+imageToRadiance (ImageYF     img) =
+    imageToRadiance . ImageRGBF $ promoteImage img
+imageToRadiance (ImageYA8    img) =
+    imageToRadiance . ImageRGB8 . promoteImage $ dropAlphaLayer img
+imageToRadiance (ImageY16    img) =
+  imageToRadiance . ImageRGBF $ pixelMap toRgbf img
+    where toRgbf v = PixelRGBF val val val
+            where val = fromIntegral v / 65536.0
+imageToRadiance (ImageY32    img) =
+  imageToRadiance . ImageRGBF $ pixelMap toRgbf img
+    where toRgbf v = PixelRGBF val val val
+            where val = fromIntegral v / 4294967296.0
+imageToRadiance (ImageYA16   img) =
+  imageToRadiance . ImageRGBF $ pixelMap toRgbf img
+    where toRgbf (PixelYA16 v _) = PixelRGBF val val val
+            where val = fromIntegral v / 65536.0
+imageToRadiance (ImageRGB16  img) =
+    imageToRadiance . ImageRGBF $ from16toFloat img
+imageToRadiance (ImageRGBA16 img) =
+    imageToRadiance . ImageRGBF $ pixelMap toRgbf img
+    where toRgbf (PixelRGBA16 r g b _) = PixelRGBF (f r) (f g) (f b)
+            where f v = fromIntegral v / 65536.0
+
+-- | This function will try to do anything to encode an image
+-- as JPEG, make all color conversion and such. Equivalent
+-- of 'decodeImage' for jpeg encoding
+-- Save Y or YCbCr Jpeg only, all other colorspaces are converted.
+-- To save a RGB or CMYK JPEG file, use the
+-- 'Codec.Picture.Jpg.Internal.encodeDirectJpegAtQualityWithMetadata' function
+imageToJpg :: Int -> DynamicImage -> L.ByteString
+imageToJpg quality dynImage =
+    let encodeAtQuality = encodeJpegAtQuality (fromIntegral quality)
+        encodeWithMeta = encodeDirectJpegAtQualityWithMetadata (fromIntegral quality) mempty
+    in case dynImage of
+        ImageYCbCr8 img -> encodeAtQuality img
+        ImageCMYK8  img -> imageToJpg quality . ImageRGB8 $ convertImage img
+        ImageCMYK16 img -> imageToJpg quality . ImageRGB16 $ convertImage img
+        ImageRGB8   img -> encodeAtQuality (convertImage img)
+        ImageRGBF   img -> imageToJpg quality . ImageRGB8 $ toStandardDef img
+        ImageRGBA8  img -> encodeAtQuality (convertImage $ dropAlphaLayer img)
+        ImageYF     img -> imageToJpg quality . ImageY8 $ greyScaleToStandardDef img
+        ImageY8     img -> encodeWithMeta img
+        ImageYA8    img -> encodeWithMeta $ dropAlphaLayer img
+        ImageY16    img -> imageToJpg quality . ImageY8 $ from16to8 img
+        ImageYA16   img -> imageToJpg quality . ImageYA8 $ from16to8 img
+        ImageY32    img -> imageToJpg quality . ImageY8 $ from32to8 img
+        ImageRGB16  img -> imageToJpg quality . ImageRGB8 $ from16to8 img
+        ImageRGBA16 img -> imageToJpg quality . ImageRGBA8 $ from16to8 img
+
+-- | This function will try to do anything to encode an image
+-- as PNG, make all color conversion and such. Equivalent
+-- of 'decodeImage' for PNG encoding
+imageToPng :: DynamicImage -> L.ByteString
+imageToPng (ImageYCbCr8 img) = encodePng (convertImage img :: Image PixelRGB8)
+imageToPng (ImageCMYK8 img)  = encodePng (convertImage img :: Image PixelRGB8)
+imageToPng (ImageCMYK16 img) = encodePng (convertImage img :: Image PixelRGB16)
+imageToPng (ImageRGB8   img) = encodePng img
+imageToPng (ImageRGBF   img) = encodePng $ toStandardDef img
+imageToPng (ImageRGBA8  img) = encodePng img
+imageToPng (ImageY8     img) = encodePng img
+imageToPng (ImageYF     img) = encodePng $ greyScaleToStandardDef img
+imageToPng (ImageYA8    img) = encodePng img
+imageToPng (ImageY16    img) = encodePng img
+imageToPng (ImageY32    img) = imageToPng . ImageY16 $ from32to16 img
+imageToPng (ImageYA16   img) = encodePng img
+imageToPng (ImageRGB16  img) = encodePng img
+imageToPng (ImageRGBA16 img) = encodePng img
+
+-- | This function will try to do anything to encode an image
+-- as a Tiff, make all color conversion and such. Equivalent
+-- of 'decodeImage' for Tiff encoding
+imageToTiff :: DynamicImage -> L.ByteString
+imageToTiff (ImageYCbCr8 img) = encodeTiff img
+imageToTiff (ImageCMYK8 img)  = encodeTiff img
+imageToTiff (ImageCMYK16 img) = encodeTiff img
+imageToTiff (ImageRGB8   img) = encodeTiff img
+imageToTiff (ImageRGBF   img) = encodeTiff $ toStandardDef img
+imageToTiff (ImageRGBA8  img) = encodeTiff img
+imageToTiff (ImageY8     img) = encodeTiff img
+imageToTiff (ImageYF     img) = encodeTiff $ greyScaleToStandardDef img
+imageToTiff (ImageYA8    img) = encodeTiff $ dropAlphaLayer img
+imageToTiff (ImageY16    img) = encodeTiff img
+imageToTiff (ImageY32    img) = encodeTiff img
+imageToTiff (ImageYA16   img) = encodeTiff $ dropAlphaLayer img
+imageToTiff (ImageRGB16  img) = encodeTiff img
+imageToTiff (ImageRGBA16 img) = encodeTiff img
+
+-- | This function will try to do anything to encode an image
+-- as bitmap, make all color conversion and such. Equivalent
+-- of 'decodeImage' for Bitmap encoding
+imageToBitmap :: DynamicImage -> L.ByteString
+imageToBitmap (ImageYCbCr8 img) = encodeBitmap (convertImage img :: Image PixelRGB8)
+imageToBitmap (ImageCMYK8  img) = encodeBitmap (convertImage img :: Image PixelRGB8)
+imageToBitmap (ImageCMYK16 img) = imageToBitmap . ImageRGB16 $ convertImage img
+imageToBitmap (ImageRGBF   img) = encodeBitmap $ toStandardDef img
+imageToBitmap (ImageRGB8   img) = encodeBitmap img
+imageToBitmap (ImageRGBA8  img) = encodeBitmap img
+imageToBitmap (ImageY8     img) = encodeBitmap img
+imageToBitmap (ImageYF     img) = encodeBitmap $ greyScaleToStandardDef img
+imageToBitmap (ImageYA8    img) = encodeBitmap (promoteImage img :: Image PixelRGBA8)
+imageToBitmap (ImageY16    img) = imageToBitmap . ImageY8 $ from16to8 img
+imageToBitmap (ImageY32    img) = imageToBitmap . ImageY8 $ from32to8 img
+imageToBitmap (ImageYA16   img) = imageToBitmap . ImageYA8 $ from16to8 img
+imageToBitmap (ImageRGB16  img) = imageToBitmap . ImageRGB8 $ from16to8 img
+imageToBitmap (ImageRGBA16 img) = imageToBitmap . ImageRGBA8 $ from16to8 img
+
+
+-- | This function will try to do anything to encode an image
+-- as a gif, make all color conversion and quantization. Equivalent
+-- of 'decodeImage' for gif encoding
+imageToGif :: DynamicImage -> Either String L.ByteString
+imageToGif (ImageYCbCr8 img) = imageToGif . ImageRGB8 $ convertImage img
+imageToGif (ImageCMYK8  img) = imageToGif . ImageRGB8 $ convertImage img
+imageToGif (ImageCMYK16 img) = imageToGif . ImageRGB16 $ convertImage img
+imageToGif (ImageRGBF   img) = imageToGif . ImageRGB8 $ toStandardDef img
+imageToGif (ImageRGB8   img) = encodeGifImageWithPalette indexed pal
+  where (indexed, pal) = palettize defaultPaletteOptions img
+imageToGif (ImageRGBA8  img) = imageToGif . ImageRGB8 $ dropAlphaLayer img
+imageToGif (ImageY8     img) = Right $ encodeGifImage img
+imageToGif (ImageYF     img) = imageToGif . ImageY8 $ greyScaleToStandardDef img
+imageToGif (ImageYA8    img) = imageToGif . ImageY8 $ dropAlphaLayer img
+imageToGif (ImageY16    img) = imageToGif . ImageY8 $ from16to8 img
+imageToGif (ImageY32    img) = imageToGif . ImageY8 $ from32to8 img
+imageToGif (ImageYA16   img) = imageToGif . ImageYA8 $ from16to8 img
+imageToGif (ImageRGB16  img) = imageToGif . ImageRGB8 $ from16to8 img
+imageToGif (ImageRGBA16 img) = imageToGif . ImageRGBA8 $ from16to8 img
+
+-- | This function will try to do anything to encode an image
+-- as a tga, make all color conversion and quantization. Equivalent
+-- of 'decodeImage' for tga encoding
+imageToTga :: DynamicImage -> L.ByteString
+imageToTga (ImageYCbCr8 img) = encodeTga (convertImage img :: Image PixelRGB8)
+imageToTga (ImageCMYK8  img) = encodeTga (convertImage img :: Image PixelRGB8)
+imageToTga (ImageCMYK16 img) = encodeTga (from16to8 img :: Image PixelRGB8)
+imageToTga (ImageRGBF   img) = encodeTga $ toStandardDef img
+imageToTga (ImageRGB8   img) = encodeTga img
+imageToTga (ImageRGBA8  img) = encodeTga img
+imageToTga (ImageY8     img) = encodeTga img
+imageToTga (ImageYF     img) = encodeTga $ greyScaleToStandardDef img
+imageToTga (ImageYA8    img) = encodeTga (promoteImage img :: Image PixelRGBA8)
+imageToTga (ImageY16    img) = encodeTga (from16to8 img :: Image Pixel8)
+imageToTga (ImageY32    img) = encodeTga (from32to8 img :: Image Pixel8)
+imageToTga (ImageYA16   img) = encodeTga (from16to8 img :: Image PixelRGBA8)
+imageToTga (ImageRGB16  img) = encodeTga (from16to8 img :: Image PixelRGB8)
+imageToTga (ImageRGBA16 img) = encodeTga (from16to8 img :: Image PixelRGBA8)
src/Codec/Picture/Tiff.hs view
@@ -4,6 +4,7 @@ {-# LANGUAGE FlexibleInstances #-}
 {-# LANGUAGE MultiParamTypeClasses #-}
 {-# LANGUAGE ScopedTypeVariables #-}
+{-# LANGUAGE InstanceSigs #-}
 {-# LANGUAGE CPP #-}
 -- | Module implementing TIFF decoding.
 --
@@ -62,9 +63,9 @@ import Codec.Picture.InternalHelper
 import Codec.Picture.BitWriter
 import Codec.Picture.Types
-import Codec.Picture.Gif.LZW
-import Codec.Picture.Tiff.Types
-import Codec.Picture.Tiff.Metadata
+import Codec.Picture.Gif.Internal.LZW
+import Codec.Picture.Tiff.Internal.Types
+import Codec.Picture.Tiff.Internal.Metadata
 import Codec.Picture.VectorByteConversion( toByteString )
 
 data TiffInfo = TiffInfo
@@ -88,6 +89,8 @@   }
 
 unLong :: String -> ExifData -> Get (V.Vector Word32)
+unLong _ (ExifLong v)   = pure $ V.singleton v
+unLong _ (ExifShort v)  = pure $ V.singleton (fromIntegral v)
 unLong _ (ExifShorts v) = pure $ V.map fromIntegral v
 unLong _ (ExifLongs v) = pure v
 unLong errMessage _ = fail errMessage
@@ -304,6 +307,33 @@ 
               looperBe (writeIndex + stride) (readIndex + 4)
 
+instance Unpackable Float where
+  type StorageType Float = Float
+
+  offsetStride _ _ _ = (0, 1)
+  outAlloc _ = M.new
+  allocTempBuffer _ _ s = M.new $ s * 4
+  mergeBackTempBuffer :: forall s. Float
+                      -> Endianness
+                      -> M.STVector s Word8
+                      -> Int
+                      -> Int
+                      -> Word32
+                      -> Int
+                      -> M.STVector s (StorageType Float)
+                      -> ST s ()
+  mergeBackTempBuffer _ endianness tempVec lineSize index size stride outVec =
+        let outVecWord32 :: M.STVector s Word32
+            outVecWord32 = M.unsafeCast outVec
+        in mergeBackTempBuffer (0 :: Word32)
+                               endianness
+                               tempVec
+                               lineSize
+                               index
+                               size
+                               stride
+                               outVecWord32
+
 data Pack4 = Pack4
 
 instance Unpackable Pack4 where
@@ -584,6 +614,10 @@                                   $ tiffColorspace nfo
       ifdShort TagPlanarConfiguration
               . constantToPlaneConfiguration $ tiffPlaneConfiguration nfo
+      ifdMultiLong TagSampleFormat
+                                  . V.fromList
+                                  . map packSampleFormat
+                                  $ tiffSampleFormat nfo
       ifdShort TagCompression . packCompression
                                     $ tiffCompression nfo
       ifdMultiLong TagStripOffsets $ tiffOffsets nfo
@@ -690,10 +724,12 @@   | lst == V.singleton 16 && all (TiffSampleUint ==) format =
         pure . TrueColorImage . ImageY16 $ gatherStrips (0 :: Word16) file nfo
   | lst == V.singleton 32 && all (TiffSampleUint ==) format =
-        let toWord16 v = fromIntegral $ v `unsafeShiftR` 16
-            img = gatherStrips (0 :: Word32) file nfo :: Image Pixel32
-        in
-        pure . TrueColorImage . ImageY16 $ pixelMap toWord16 img
+        let img = gatherStrips (0 :: Word32) file nfo :: Image Pixel32
+        in pure $ TrueColorImage $ ImageY32 $ img
+  | lst == V.singleton 32 && all (TiffSampleFloat ==) format =
+        let img = gatherStrips (0 :: Float) file nfo :: Image PixelF
+        in pure $ TrueColorImage $ ImageYF $ img
+  | lst == V.singleton 64 = Left "Failure to unpack TIFF file, 64-bit samples unsupported."
   | lst == V.fromList [2, 2] && all (TiffSampleUint ==) format =
         pure . TrueColorImage . ImageYA8 . pixelMap (colorMap (0x55 *)) $ gatherStrips Pack2 file nfo
   | lst == V.fromList [4, 4] && all (TiffSampleUint ==) format =
@@ -758,6 +794,10 @@ --
 --  * 'ImageY16'
 --
+--  * 'ImageY32'
+--
+--  * 'ImageYF'
+--
 --  * 'ImageYA8'
 --
 --  * 'ImageYA16'
@@ -803,12 +843,22 @@   subSamplingInfo   :: px -> V.Vector Word32
   subSamplingInfo _ = V.empty
 
+  sampleFormat :: px -> [TiffSampleFormat]
+  sampleFormat _ = [TiffSampleUint]
+
 instance TiffSaveable Pixel8 where
   colorSpaceOfPixel _ = TiffMonochrome
 
 instance TiffSaveable Pixel16 where
   colorSpaceOfPixel _ = TiffMonochrome
 
+instance TiffSaveable Pixel32 where
+  colorSpaceOfPixel _ = TiffMonochrome
+
+instance TiffSaveable PixelF where
+  colorSpaceOfPixel _ = TiffMonochrome
+  sampleFormat _      = [TiffSampleFloat]
+
 instance TiffSaveable PixelYA8 where
   colorSpaceOfPixel _ = TiffMonochrome
   extraSampleCodeOfPixel _ = Just ExtraSampleUnassociatedAlpha
@@ -871,7 +921,7 @@             , tiffSampleCount        = fromIntegral sampleCount
             , tiffRowPerStrip        = fromIntegral $ imageHeight img
             , tiffPlaneConfiguration = PlanarConfigContig
-            , tiffSampleFormat       = [TiffSampleUint]
+            , tiffSampleFormat       = sampleFormat (undefined :: px)
             , tiffBitsPerSample      = V.replicate intSampleCount bitPerSample
             , tiffCompression        = CompressionNone
             , tiffStripSize          = V.singleton imageSize
+ src/Codec/Picture/Tiff/Internal/Metadata.hs view
@@ -0,0 +1,239 @@+{-# LANGUAGE CPP #-}
+module Codec.Picture.Tiff.Internal.Metadata
+    ( extractTiffMetadata
+    , encodeTiffStringMetadata
+    , exifOffsetIfd
+    ) where
+
+#if !MIN_VERSION_base(4,8,0)
+import Data.Monoid( mempty )
+import Data.Foldable( foldMap )
+import Control.Applicative( (<$>) )
+#endif
+
+import Data.Bits( unsafeShiftL, (.|.) )
+import Data.Foldable( find )
+import Data.List( sortBy )
+import Data.Function( on )
+import qualified Data.Foldable as F
+#if !MIN_VERSION_base(4,11,0)
+import Data.Monoid( (<>) )
+#endif
+import Codec.Picture.Metadata( Metadatas )
+import qualified Data.ByteString as B
+import qualified Data.ByteString.Char8 as BC
+import qualified Codec.Picture.Metadata as Met
+import qualified Data.Vector.Generic as V
+import Codec.Picture.Tiff.Internal.Types
+import Codec.Picture.Metadata( extractExifMetas )
+import Codec.Picture.Metadata.Exif
+
+exifOffsetIfd :: ImageFileDirectory
+exifOffsetIfd = ImageFileDirectory
+  { ifdIdentifier = TagExifOffset
+  , ifdCount = 1
+  , ifdType = TypeLong
+  , ifdOffset = 0
+  , ifdExtended = ExifNone
+  }
+
+typeOfData :: ExifData -> IfdType
+typeOfData d = case d of
+  ExifNone -> error "Impossible - typeOfData : ExifNone"
+  ExifIFD _exifs -> error "Impossible - typeOfData : ExifIFD"
+  ExifLong _l -> TypeLong
+  ExifLongs _l -> TypeLong
+  ExifShort _s -> TypeShort
+  ExifShorts _s -> TypeShort
+  ExifString _str -> TypeAscii
+  ExifUndefined _undef -> TypeUndefined
+  ExifRational _r1 _r2 -> TypeRational
+  ExifSignedRational _sr1 _sr2 -> TypeSignedRational
+
+makeIfd :: ExifTag -> ExifData -> ImageFileDirectory
+makeIfd t (ExifShort v) = ImageFileDirectory
+  { ifdIdentifier = t
+  , ifdType = TypeShort
+  , ifdCount = 1
+  , ifdOffset = fromIntegral v `unsafeShiftL` 16
+  , ifdExtended = ExifNone
+  }
+makeIfd t (ExifLong v) = ImageFileDirectory 
+  { ifdIdentifier = t
+  , ifdType = TypeLong
+  , ifdCount = 1
+  , ifdOffset = fromIntegral v
+  , ifdExtended = ExifNone
+  }
+makeIfd t d@(ExifShorts v)
+  | size == 2 = ImageFileDirectory
+    { ifdIdentifier = t
+    , ifdType = TypeShort
+    , ifdCount = 2
+    , ifdOffset = combined
+    , ifdExtended = ExifNone
+    }
+  | otherwise = ImageFileDirectory
+    { ifdIdentifier = t
+    , ifdType = TypeShort
+    , ifdCount = size
+    , ifdOffset = 0
+    , ifdExtended = d
+    }
+  where
+    size = fromIntegral $ F.length v
+    at i = fromIntegral $ v V.! i
+    combined = (at 0  `unsafeShiftL` 16) .|. at 1
+makeIfd t d@(ExifLongs v)
+  | size == 1 = ImageFileDirectory
+    { ifdIdentifier = t
+    , ifdType = TypeLong
+    , ifdCount = 1
+    , ifdOffset = v V.! 0
+    , ifdExtended = ExifNone
+    }
+  | otherwise = ImageFileDirectory
+    { ifdIdentifier = t
+    , ifdType = TypeLong
+    , ifdCount = size
+    , ifdOffset = 0
+    , ifdExtended = d
+    }
+  where size = fromIntegral $ F.length v
+makeIfd t s@(ExifString str) = ImageFileDirectory
+    { ifdIdentifier = t
+    , ifdType = TypeAscii
+    , ifdCount = fromIntegral $ BC.length str
+    , ifdOffset = 0
+    , ifdExtended = s
+    }
+makeIfd t s@(ExifUndefined str)
+  | size > 4 = ImageFileDirectory
+    { ifdIdentifier = t
+    , ifdType = TypeUndefined
+    , ifdCount = size
+    , ifdOffset = 0
+    , ifdExtended = s
+    }
+  | otherwise = ImageFileDirectory
+    { ifdIdentifier = t
+    , ifdType = TypeUndefined
+    , ifdCount = size
+    , ifdOffset = ofs
+    , ifdExtended = ExifNone
+    }
+  where
+    size = fromIntegral $ BC.length str
+    at ix
+      | fromIntegral ix < size = fromIntegral $ B.index str ix `unsafeShiftL` (4 - (8 * ix))
+      | otherwise = 0
+    ofs = at 0 .|. at 1 .|. at 2 .|. at 3
+makeIfd t d = ImageFileDirectory
+  { ifdIdentifier = t
+  , ifdType = typeOfData d
+  , ifdCount = 1
+  , ifdOffset = 0
+  , ifdExtended = d
+  }
+
+encodeTiffStringMetadata :: Metadatas -> [ImageFileDirectory]
+encodeTiffStringMetadata metas = sortBy (compare `on` word16OfTag . ifdIdentifier) $ allTags where
+  keyStr tag k = case Met.lookup k metas of
+    Nothing -> mempty
+    Just v -> pure . makeIfd tag . ExifString $ BC.pack v
+  allTags = copyright <> artist <> title <> description <> software <> allPureExif
+
+  allPureExif = fmap (uncurry makeIfd) $ extractExifMetas metas
+
+  copyright = keyStr TagCopyright Met.Copyright
+  artist = keyStr TagArtist Met.Author
+  title = keyStr TagDocumentName Met.Title
+  description = keyStr TagImageDescription Met.Description
+  software = keyStr TagSoftware Met.Software
+
+extractTiffStringMetadata :: [ImageFileDirectory] -> Metadatas
+extractTiffStringMetadata = Met.insert Met.Format Met.SourceTiff . foldMap go where
+  strMeta k = Met.singleton k . BC.unpack
+  exif ifd =
+    Met.singleton (Met.Exif $ ifdIdentifier ifd) $ ifdExtended ifd
+  inserter acc (k, v) = Met.insert (Met.Exif k) v acc
+  exifShort ifd =
+    Met.singleton (Met.Exif $ ifdIdentifier ifd) . (ExifShort . fromIntegral) $ ifdOffset ifd
+
+  go :: ImageFileDirectory -> Metadatas
+  go ifd = case (ifdIdentifier ifd, ifdExtended ifd) of
+    (TagArtist, ExifString v) -> strMeta Met.Author v
+    (TagBitsPerSample, _) -> mempty
+    (TagColorMap, _) -> mempty
+    (TagCompression, _) -> mempty
+    (TagCopyright, ExifString v) -> strMeta Met.Copyright v
+    (TagDocumentName, ExifString v) -> strMeta Met.Title v
+    (TagExifOffset, ExifIFD lst) -> F.foldl' inserter mempty lst
+    (TagImageDescription, ExifString v) -> strMeta Met.Description v
+    (TagImageLength, _) -> Met.singleton Met.Height . fromIntegral $ ifdOffset ifd
+    (TagImageWidth, _) -> Met.singleton Met.Width . fromIntegral $ ifdOffset ifd
+    (TagJPEGACTables, _) -> mempty
+    (TagJPEGDCTables, _) -> mempty
+    (TagJPEGInterchangeFormat, _) -> mempty
+    (TagJPEGInterchangeFormatLength, _) -> mempty
+    (TagJPEGLosslessPredictors, _) -> mempty
+    (TagJPEGPointTransforms, _) -> mempty
+    (TagJPEGQTables, _) -> mempty
+    (TagJPEGRestartInterval, _) -> mempty
+    (TagJpegProc, _) -> mempty
+    (TagModel, v) -> Met.singleton (Met.Exif TagModel) v
+    (TagMake, v) -> Met.singleton (Met.Exif TagMake) v
+    (TagOrientation, _) -> exifShort ifd
+    (TagResolutionUnit, _) -> mempty
+    (TagRowPerStrip, _) -> mempty
+    (TagSamplesPerPixel, _) -> mempty
+    (TagSoftware, ExifString v) -> strMeta Met.Software v
+    (TagStripByteCounts, _) -> mempty
+    (TagStripOffsets, _) -> mempty
+    (TagTileByteCount, _) -> mempty
+    (TagTileLength, _) -> mempty
+    (TagTileOffset, _) -> mempty
+    (TagTileWidth, _) -> mempty
+    (TagUnknown _, _) -> exif ifd
+    (TagXResolution, _) -> mempty
+    (TagYCbCrCoeff, _) -> mempty
+    (TagYCbCrPositioning, _) -> mempty
+    (TagYCbCrSubsampling, _) -> mempty
+    (TagYResolution, _) -> mempty
+    _ -> mempty
+
+byTag :: ExifTag -> ImageFileDirectory -> Bool
+byTag t ifd = ifdIdentifier ifd == t
+
+data TiffResolutionUnit
+  = ResolutionUnitUnknown
+  | ResolutionUnitInch
+  | ResolutionUnitCentimeter
+
+unitOfIfd :: ImageFileDirectory -> TiffResolutionUnit
+unitOfIfd ifd = case (ifdType ifd, ifdOffset ifd) of
+  (TypeShort, 1) -> ResolutionUnitUnknown
+  (TypeShort, 2) -> ResolutionUnitInch
+  (TypeShort, 3) -> ResolutionUnitCentimeter
+  _ -> ResolutionUnitUnknown
+
+extractTiffDpiMetadata :: [ImageFileDirectory] -> Metadatas
+extractTiffDpiMetadata lst = go where
+  go = case unitOfIfd <$> find (byTag TagResolutionUnit) lst of
+    Nothing -> mempty
+    Just ResolutionUnitUnknown -> mempty
+    Just ResolutionUnitCentimeter -> findDpis Met.dotsPerCentiMeterToDotPerInch mempty
+    Just ResolutionUnitInch -> findDpis id mempty
+
+  findDpis toDpi =
+     findDpi Met.DpiX TagXResolution toDpi . findDpi Met.DpiY TagYResolution toDpi
+
+  findDpi k tag toDpi metas = case find (byTag tag) lst of
+    Nothing -> metas
+    Just ImageFileDirectory { ifdExtended = ExifRational num den } ->
+      Met.insert k (toDpi . fromIntegral $ num `div` den) metas
+    Just _ -> metas
+
+extractTiffMetadata :: [ImageFileDirectory] -> Metadatas
+extractTiffMetadata lst = extractTiffDpiMetadata lst <> extractTiffStringMetadata lst
+
+ src/Codec/Picture/Tiff/Internal/Types.hs view
@@ -0,0 +1,504 @@+{-# LANGUAGE CPP #-}
+{-# LANGUAGE DeriveGeneric #-}
+{-# LANGUAGE MultiParamTypeClasses #-}
+{-# LANGUAGE FlexibleInstances #-}
+{-# LANGUAGE FlexibleContexts #-}
+module Codec.Picture.Tiff.Internal.Types
+    ( BinaryParam( .. )
+    , Endianness( .. )
+    , TiffHeader( .. )
+    , TiffPlanarConfiguration( .. )
+    , TiffCompression( .. )
+    , IfdType( .. )
+    , TiffColorspace( .. )
+    , TiffSampleFormat( .. )
+    , ImageFileDirectory( .. )
+    , ExtraSample( .. )
+    , Predictor( .. )
+
+    , planarConfgOfConstant
+    , constantToPlaneConfiguration
+    , unpackSampleFormat
+    , packSampleFormat
+    , word16OfTag
+    , unpackPhotometricInterpretation
+    , packPhotometricInterpretation
+    , codeOfExtraSample
+    , unPackCompression
+    , packCompression 
+    , predictorOfConstant
+    ) where
+
+#if !MIN_VERSION_base(4,8,0)
+import Control.Applicative( (<$>), (<*>), pure )
+#endif
+
+import Control.DeepSeq( NFData(..) )
+import Control.Monad( forM_, when, replicateM, )
+import Data.Bits( (.&.), unsafeShiftR )
+import Data.Binary( Binary( .. ) )
+import Data.Binary.Get( Get
+                      , getWord16le, getWord16be
+                      , getWord32le, getWord32be
+                      , bytesRead
+                      , skip
+                      , getByteString
+                      )
+import Data.Binary.Put( Put
+                      , putWord16le, putWord16be
+                      , putWord32le, putWord32be
+                      , putByteString
+                      )
+import Data.Function( on )
+import Data.List( sortBy, mapAccumL )
+import qualified Data.Vector as V
+import qualified Data.ByteString as B
+import Data.Int( Int32 )
+import Data.Word( Word8, Word16, Word32 )
+import GHC.Generics( Generic )
+
+import Codec.Picture.Metadata.Exif
+{-import Debug.Trace-}
+
+data Endianness
+  = EndianLittle
+  | EndianBig
+  deriving (Eq, Show)
+
+instance Binary Endianness where
+  put EndianLittle = putWord16le 0x4949
+  put EndianBig = putWord16le 0x4D4D
+
+  get = do
+    tag <- getWord16le
+    case tag of
+      0x4949 -> return EndianLittle
+      0x4D4D -> return EndianBig
+      _ -> fail "Invalid endian tag value"
+
+-- | Because having a polymorphic get with endianness is to nice
+-- to pass on, introducing this helper type class, which is just
+-- a superset of Binary, but formalising a parameter passing
+-- into it.
+class BinaryParam a b where
+  getP :: a -> Get b
+  putP :: a -> b -> Put
+
+data TiffHeader = TiffHeader
+  { hdrEndianness :: !Endianness
+  , hdrOffset     :: {-# UNPACK #-} !Word32
+  }
+  deriving (Eq, Show)
+
+instance BinaryParam Endianness Word16 where
+  putP EndianLittle = putWord16le
+  putP EndianBig = putWord16be
+
+  getP EndianLittle = getWord16le
+  getP EndianBig = getWord16be
+
+instance BinaryParam Endianness Int32 where
+  putP en v = putP en $ (fromIntegral v :: Word32)
+  getP en = fromIntegral <$> (getP en :: Get Word32) 
+
+instance BinaryParam Endianness Word32 where
+  putP EndianLittle = putWord32le
+  putP EndianBig = putWord32be
+
+  getP EndianLittle = getWord32le
+  getP EndianBig = getWord32be
+
+instance Binary TiffHeader where
+  put hdr = do
+    let endian = hdrEndianness hdr
+    put endian
+    putP endian (42 :: Word16)
+    putP endian $ hdrOffset hdr
+
+  get = do
+    endian <- get
+    magic <- getP endian
+    let magicValue = 42 :: Word16
+    when (magic /= magicValue)
+         (fail "Invalid TIFF magic number")
+    TiffHeader endian <$> getP endian
+
+data TiffPlanarConfiguration
+  = PlanarConfigContig    -- = 1
+  | PlanarConfigSeparate  -- = 2
+
+planarConfgOfConstant :: Word32 -> Get TiffPlanarConfiguration
+planarConfgOfConstant 0 = pure PlanarConfigContig
+planarConfgOfConstant 1 = pure PlanarConfigContig
+planarConfgOfConstant 2 = pure PlanarConfigSeparate
+planarConfgOfConstant v = fail $ "Unknown planar constant (" ++ show v ++ ")"
+
+constantToPlaneConfiguration :: TiffPlanarConfiguration -> Word16
+constantToPlaneConfiguration PlanarConfigContig = 1
+constantToPlaneConfiguration PlanarConfigSeparate = 2
+
+data TiffCompression
+  = CompressionNone           -- 1
+  | CompressionModifiedRLE    -- 2
+  | CompressionLZW            -- 5
+  | CompressionJPEG           -- 6
+  | CompressionPackBit        -- 32273
+
+data IfdType
+  = TypeByte
+  | TypeAscii
+  | TypeShort
+  | TypeLong
+  | TypeRational
+  | TypeSByte
+  | TypeUndefined
+  | TypeSignedShort
+  | TypeSignedLong
+  | TypeSignedRational
+  | TypeFloat
+  | TypeDouble
+  deriving (Eq, Show, Generic)
+instance NFData IfdType
+
+instance BinaryParam Endianness IfdType where
+    getP endianness = getP endianness >>= conv where
+      conv :: Word16 -> Get IfdType
+      conv v = case v of
+        1  -> return TypeByte
+        2  -> return TypeAscii
+        3  -> return TypeShort
+        4  -> return TypeLong
+        5  -> return TypeRational
+        6  -> return TypeSByte
+        7  -> return TypeUndefined
+        8  -> return TypeSignedShort
+        9  -> return TypeSignedLong
+        10 -> return TypeSignedRational
+        11 -> return TypeFloat
+        12 -> return TypeDouble
+        _  -> fail "Invalid TIF directory type"
+
+    putP endianness = putP endianness . conv where
+      conv :: IfdType -> Word16
+      conv v = case v of
+        TypeByte -> 1
+        TypeAscii -> 2
+        TypeShort -> 3
+        TypeLong -> 4
+        TypeRational -> 5
+        TypeSByte -> 6
+        TypeUndefined -> 7
+        TypeSignedShort -> 8
+        TypeSignedLong -> 9
+        TypeSignedRational -> 10
+        TypeFloat -> 11
+        TypeDouble -> 12
+
+instance BinaryParam Endianness ExifTag where
+  getP endianness = tagOfWord16 <$> getP endianness
+  putP endianness = putP endianness . word16OfTag
+
+data Predictor
+  = PredictorNone                   -- 1
+  | PredictorHorizontalDifferencing -- 2
+  deriving Eq
+
+predictorOfConstant :: Word32 -> Get Predictor
+predictorOfConstant 1 = pure PredictorNone
+predictorOfConstant 2 = pure PredictorHorizontalDifferencing
+predictorOfConstant v = fail $ "Unknown predictor (" ++ show v ++ ")"
+
+paddWrite :: B.ByteString -> Put
+paddWrite str = putByteString str >> padding where
+  zero = 0 :: Word8
+  padding = when (odd (B.length str)) $ put zero
+
+instance BinaryParam (Endianness, Int, ImageFileDirectory) ExifData where
+  putP (endianness, _, _) = dump
+    where
+      dump ExifNone = pure ()
+      dump (ExifLong _) = pure ()
+      dump (ExifShort _) = pure ()
+      dump (ExifIFD _) = pure ()
+      dump (ExifString bstr) = paddWrite bstr
+      dump (ExifUndefined bstr) = paddWrite bstr
+      -- wrong if length == 2
+      dump (ExifShorts shorts) = V.mapM_ (putP endianness) shorts
+      dump (ExifLongs longs) = V.mapM_ (putP endianness) longs
+      dump (ExifRational a b) = putP endianness a >> putP endianness b
+      dump (ExifSignedRational a b) = putP endianness a >> putP endianness b
+
+  getP (endianness, maxi, ifd) = fetcher ifd
+    where
+      align ImageFileDirectory { ifdOffset = offset } act = do
+        readed <- bytesRead
+        let delta = fromIntegral offset - readed
+        if offset >= fromIntegral maxi || fromIntegral readed > offset then
+          pure ExifNone
+        else do
+          skip $ fromIntegral delta
+          act
+
+      getE :: (BinaryParam Endianness a) => Get a
+      getE = getP endianness
+
+      getVec count = V.replicateM (fromIntegral count)
+
+      immediateBytes ofs =
+        let bytes = [fromIntegral $ (ofs .&. 0xFF000000) `unsafeShiftR` (3 * 8)
+                    ,fromIntegral $ (ofs .&. 0x00FF0000) `unsafeShiftR` (2 * 8)
+                    ,fromIntegral $ (ofs .&. 0x0000FF00) `unsafeShiftR` (1 * 8)
+                    ,fromIntegral $  ofs .&. 0x000000FF
+                    ]
+        in case endianness of
+             EndianLittle -> reverse bytes
+             EndianBig    -> bytes
+
+      fetcher ImageFileDirectory { ifdIdentifier = TagExifOffset
+                                 , ifdType = TypeLong
+                                 , ifdCount = 1 } = do
+         align ifd $ do
+            let byOffset = sortBy (compare `on` ifdOffset)
+                cleansIfds = fmap (cleanImageFileDirectory endianness)
+            subIfds <- cleansIfds . byOffset <$> getP endianness
+            cleaned <- fetchExtended endianness maxi $ sortBy (compare `on` ifdOffset) subIfds
+            pure $ ExifIFD [(ifdIdentifier fd, ifdExtended fd) | fd <- cleaned]
+         {-  
+      fetcher ImageFileDirectory { ifdIdentifier = TagGPSInfo
+                                 , ifdType = TypeLong
+                                 , ifdCount = 1 } = do
+         align ifd 
+         subIfds <- fmap (cleanImageFileDirectory endianness) <$> getP endianness
+         cleaned <- fetchExtended endianness subIfds
+         pure $ ExifIFD [(ifdIdentifier fd, ifdExtended fd) | fd <- cleaned]
+        -}
+      fetcher ImageFileDirectory { ifdType = TypeUndefined, ifdCount = count } | count > 4 =
+         align ifd $ ExifUndefined <$> getByteString (fromIntegral count)
+      fetcher ImageFileDirectory { ifdType = TypeUndefined, ifdOffset = ofs } =
+          pure . ExifUndefined . B.pack $ take (fromIntegral $ ifdCount ifd)
+              (immediateBytes ofs)
+      fetcher ImageFileDirectory { ifdType = TypeAscii, ifdCount = count } | count > 4 =
+          align ifd $ ExifString <$> getByteString (fromIntegral count)
+      fetcher ImageFileDirectory { ifdType = TypeAscii, ifdOffset = ofs } =
+          pure . ExifString . B.pack $ take (fromIntegral $ ifdCount ifd)
+              (immediateBytes ofs)
+      fetcher ImageFileDirectory { ifdType = TypeShort, ifdCount = 2, ifdOffset = ofs } =
+          pure . ExifShorts $ V.fromListN 2 valList
+            where high = fromIntegral $ ofs `unsafeShiftR` 16
+                  low = fromIntegral $ ofs .&. 0xFFFF
+                  valList = case endianness of
+                    EndianLittle -> [low, high]
+                    EndianBig -> [high, low]
+      fetcher ImageFileDirectory { ifdType = TypeRational, ifdCount = 1 } = do
+          align ifd $ ExifRational <$> getP EndianLittle <*> getP EndianLittle
+      fetcher ImageFileDirectory { ifdType = TypeSignedRational, ifdCount = 1 } = do
+          align ifd $ ExifSignedRational <$> getP EndianLittle <*> getP EndianLittle
+      fetcher ImageFileDirectory { ifdType = TypeShort, ifdCount = 1 } =
+          pure . ExifShort . fromIntegral $ ifdOffset ifd
+      fetcher ImageFileDirectory { ifdType = TypeShort, ifdCount = count } | count > 2 =
+          align ifd $ ExifShorts <$> getVec count getE
+      fetcher ImageFileDirectory { ifdType = TypeLong, ifdCount = 1 } =
+          pure . ExifLong . fromIntegral $ ifdOffset ifd
+      fetcher ImageFileDirectory { ifdType = TypeLong, ifdCount = count } | count > 1 =
+          align ifd $ ExifLongs <$> getVec count getE
+      fetcher _ = pure ExifNone
+
+cleanImageFileDirectory :: Endianness -> ImageFileDirectory -> ImageFileDirectory
+cleanImageFileDirectory EndianBig ifd@(ImageFileDirectory { ifdCount = 1 }) = aux $ ifdType ifd
+  where
+    aux TypeShort = ifd { ifdOffset = ifdOffset ifd `unsafeShiftR` 16 }
+    aux _ = ifd
+cleanImageFileDirectory _ ifd = ifd
+
+fetchExtended :: Endianness -> Int -> [ImageFileDirectory] -> Get [ImageFileDirectory]
+fetchExtended endian maxi = mapM $ \ifd -> do
+  v <- getP (endian, maxi, ifd)
+  pure $ ifd { ifdExtended = v }
+
+-- | All the IFD must be written in order according to the tag
+-- value of the IFD. To avoid getting to much restriction in the
+-- serialization code, just sort it.
+orderIfdByTag :: [ImageFileDirectory] -> [ImageFileDirectory]
+orderIfdByTag = sortBy comparer where
+  comparer a b = compare t1 t2 where
+    t1 = word16OfTag $ ifdIdentifier a
+    t2 = word16OfTag $ ifdIdentifier b
+
+-- | Given an official offset and a list of IFD, update the offset information
+-- of the IFD with extended data.
+setupIfdOffsets :: Word32 -> [ImageFileDirectory] -> (Word32, [ImageFileDirectory])
+setupIfdOffsets initialOffset lst = mapAccumL updater startExtended lst
+  where ifdElementCount = fromIntegral $ length lst
+        ifdSize = 12
+        ifdCountSize = 2
+        nextOffsetSize = 4
+        startExtended = initialOffset
+                     + ifdElementCount * ifdSize
+                     + ifdCountSize + nextOffsetSize
+
+        paddedSize blob = fromIntegral $ blobLength + padding where
+          blobLength = B.length blob
+          padding = if odd blobLength then 1 else 0
+
+        updater ix ifd@(ImageFileDirectory { ifdIdentifier = TagExifOffset }) =
+            (ix, ifd { ifdOffset = ix } )
+        updater ix ifd@(ImageFileDirectory { ifdExtended = ExifUndefined b }) =
+            (ix + paddedSize b, ifd { ifdOffset = ix } )
+        updater ix ifd@(ImageFileDirectory { ifdExtended = ExifString b }) =
+            (ix + paddedSize b, ifd { ifdOffset = ix } )
+        updater ix ifd@(ImageFileDirectory { ifdExtended = ExifLongs v })
+            | V.length v > 1 = ( ix + fromIntegral (V.length v * 4)
+                               , ifd { ifdOffset = ix } )
+        updater ix ifd@(ImageFileDirectory { ifdExtended = ExifShorts v })
+            | V.length v > 2 = ( ix + fromIntegral (V.length v * 2)
+                             , ifd { ifdOffset = ix })
+        updater ix ifd = (ix, ifd)
+
+instance BinaryParam B.ByteString (TiffHeader, [[ImageFileDirectory]]) where
+  putP rawData (hdr, ifds) = do
+    put hdr
+    putByteString rawData
+    let endianness = hdrEndianness hdr
+        (_, offseted) = mapAccumL
+            (\ix ifd -> setupIfdOffsets ix $ orderIfdByTag ifd)
+            (hdrOffset hdr)
+            ifds
+    forM_ offseted $ \list -> do
+        putP endianness list
+        mapM_ (\field -> putP (endianness, (0::Int), field) $ ifdExtended field) list
+
+  getP raw = do
+    hdr <- get
+    readed <- bytesRead
+    skip . fromIntegral $ fromIntegral (hdrOffset hdr) - readed
+    let endian = hdrEndianness hdr
+        byOffset = sortBy (compare `on` ifdOffset)
+        cleanIfds = fmap (cleanImageFileDirectory endian)
+
+    ifd <-  cleanIfds . byOffset <$> getP endian
+    cleaned <- fetchExtended endian (B.length raw) ifd
+    return (hdr, [cleaned])
+
+data TiffSampleFormat
+  = TiffSampleUint
+  | TiffSampleInt
+  | TiffSampleFloat
+  | TiffSampleUnknown
+  deriving Eq
+
+unpackSampleFormat :: Word32 -> Get TiffSampleFormat
+unpackSampleFormat v = case v of
+  1 -> pure TiffSampleUint
+  2 -> pure TiffSampleInt
+  3 -> pure TiffSampleFloat
+  4 -> pure TiffSampleUnknown
+  vv -> fail $ "Undefined data format (" ++ show vv ++ ")"
+
+packSampleFormat :: TiffSampleFormat -> Word32
+packSampleFormat TiffSampleUint    = 1
+packSampleFormat TiffSampleInt     = 2
+packSampleFormat TiffSampleFloat   = 3
+packSampleFormat TiffSampleUnknown = 4
+
+data ImageFileDirectory = ImageFileDirectory
+  { ifdIdentifier :: !ExifTag -- Word16
+  , ifdType       :: !IfdType -- Word16
+  , ifdCount      :: !Word32
+  , ifdOffset     :: !Word32
+  , ifdExtended   :: !ExifData
+  }
+  deriving (Eq, Show, Generic)
+instance NFData ImageFileDirectory
+
+instance BinaryParam Endianness ImageFileDirectory where
+  getP endianness =
+    ImageFileDirectory <$> getE <*> getE <*> getE <*> getE
+                       <*> pure ExifNone
+        where getE :: (BinaryParam Endianness a) => Get a
+              getE = getP endianness
+
+  putP endianness ifd = do
+    let putE :: (BinaryParam Endianness a) => a -> Put
+        putE = putP endianness
+    putE $ ifdIdentifier ifd
+    putE $ ifdType ifd
+    putE $ ifdCount ifd
+    putE $ ifdOffset ifd
+
+instance BinaryParam Endianness [ImageFileDirectory] where
+  getP endianness = do
+    count <- getP endianness :: Get Word16
+    rez <- replicateM (fromIntegral count) $ getP endianness
+    _ <- getP endianness :: Get Word32
+    pure rez
+
+
+  putP endianness lst = do
+    let count = fromIntegral $ length lst :: Word16
+    putP endianness count
+    mapM_ (putP endianness) lst
+    putP endianness (0 :: Word32)
+
+data TiffColorspace
+  = TiffMonochromeWhite0 -- ^ 0
+  | TiffMonochrome       -- ^ 1
+  | TiffRGB              -- ^ 2
+  | TiffPaleted          -- ^ 3
+  | TiffTransparencyMask -- ^ 4
+  | TiffCMYK             -- ^ 5
+  | TiffYCbCr            -- ^ 6
+  | TiffCIELab           -- ^ 8
+
+
+packPhotometricInterpretation :: TiffColorspace -> Word16
+packPhotometricInterpretation v = case v of
+  TiffMonochromeWhite0 -> 0
+  TiffMonochrome       -> 1
+  TiffRGB              -> 2
+  TiffPaleted          -> 3
+  TiffTransparencyMask -> 4
+  TiffCMYK             -> 5
+  TiffYCbCr            -> 6
+  TiffCIELab           -> 8
+
+unpackPhotometricInterpretation :: Word32 -> Get TiffColorspace
+unpackPhotometricInterpretation v = case v of
+  0 -> pure TiffMonochromeWhite0
+  1 -> pure TiffMonochrome
+  2 -> pure TiffRGB
+  3 -> pure TiffPaleted
+  4 -> pure TiffTransparencyMask
+  5 -> pure TiffCMYK
+  6 -> pure TiffYCbCr
+  8 -> pure TiffCIELab
+  vv -> fail $ "Unrecognized color space " ++ show vv
+
+data ExtraSample
+  = ExtraSampleUnspecified       -- ^ 0
+  | ExtraSampleAssociatedAlpha   -- ^ 1
+  | ExtraSampleUnassociatedAlpha -- ^ 2
+
+codeOfExtraSample :: ExtraSample -> Word16
+codeOfExtraSample v = case v of
+  ExtraSampleUnspecified -> 0
+  ExtraSampleAssociatedAlpha -> 1
+  ExtraSampleUnassociatedAlpha -> 2
+
+unPackCompression :: Word32 -> Get TiffCompression
+unPackCompression v = case v of
+  0 -> pure CompressionNone
+  1 -> pure CompressionNone
+  2 -> pure CompressionModifiedRLE
+  5 -> pure CompressionLZW
+  6 -> pure CompressionJPEG
+  32773 -> pure CompressionPackBit
+  vv -> fail $ "Unknown compression scheme " ++ show vv
+
+packCompression :: TiffCompression -> Word16
+packCompression v = case v of
+  CompressionNone        -> 1
+  CompressionModifiedRLE -> 2
+  CompressionLZW         -> 5
+  CompressionJPEG        -> 6
+  CompressionPackBit     -> 32773
+
− src/Codec/Picture/Tiff/Metadata.hs
@@ -1,237 +0,0 @@-{-# LANGUAGE CPP #-}
-module Codec.Picture.Tiff.Metadata
-    ( extractTiffMetadata
-    , encodeTiffStringMetadata
-    , exifOffsetIfd
-    ) where
-
-#if !MIN_VERSION_base(4,8,0)
-import Data.Monoid( mempty )
-import Data.Foldable( foldMap )
-import Control.Applicative( (<$>) )
-#endif
-
-import Data.Bits( unsafeShiftL, (.|.) )
-import Data.Foldable( find )
-import Data.List( sortBy )
-import Data.Function( on )
-import qualified Data.Foldable as F
-import Data.Monoid( (<>) )
-import Codec.Picture.Metadata( Metadatas )
-import qualified Data.ByteString as B
-import qualified Data.ByteString.Char8 as BC
-import qualified Codec.Picture.Metadata as Met
-import qualified Data.Vector.Generic as V
-import Codec.Picture.Tiff.Types
-import Codec.Picture.Metadata( extractExifMetas )
-import Codec.Picture.Metadata.Exif
-
-exifOffsetIfd :: ImageFileDirectory
-exifOffsetIfd = ImageFileDirectory
-  { ifdIdentifier = TagExifOffset
-  , ifdCount = 1
-  , ifdType = TypeLong
-  , ifdOffset = 0
-  , ifdExtended = ExifNone
-  }
-
-typeOfData :: ExifData -> IfdType
-typeOfData d = case d of
-  ExifNone -> error "Impossible - typeOfData : ExifNone"
-  ExifIFD _exifs -> error "Impossible - typeOfData : ExifIFD"
-  ExifLong _l -> TypeLong
-  ExifLongs _l -> TypeLong
-  ExifShort _s -> TypeShort
-  ExifShorts _s -> TypeShort
-  ExifString _str -> TypeAscii
-  ExifUndefined _undef -> TypeUndefined
-  ExifRational _r1 _r2 -> TypeRational
-  ExifSignedRational _sr1 _sr2 -> TypeSignedRational
-
-makeIfd :: ExifTag -> ExifData -> ImageFileDirectory
-makeIfd t (ExifShort v) = ImageFileDirectory
-  { ifdIdentifier = t
-  , ifdType = TypeShort
-  , ifdCount = 1
-  , ifdOffset = fromIntegral v `unsafeShiftL` 16
-  , ifdExtended = ExifNone
-  }
-makeIfd t (ExifLong v) = ImageFileDirectory 
-  { ifdIdentifier = t
-  , ifdType = TypeLong
-  , ifdCount = 1
-  , ifdOffset = fromIntegral v
-  , ifdExtended = ExifNone
-  }
-makeIfd t d@(ExifShorts v)
-  | size == 2 = ImageFileDirectory
-    { ifdIdentifier = t
-    , ifdType = TypeShort
-    , ifdCount = 2
-    , ifdOffset = combined
-    , ifdExtended = ExifNone
-    }
-  | otherwise = ImageFileDirectory
-    { ifdIdentifier = t
-    , ifdType = TypeShort
-    , ifdCount = size
-    , ifdOffset = 0
-    , ifdExtended = d
-    }
-  where
-    size = fromIntegral $ F.length v
-    at i = fromIntegral $ v V.! i
-    combined = (at 0  `unsafeShiftL` 16) .|. at 1
-makeIfd t d@(ExifLongs v)
-  | size == 1 = ImageFileDirectory
-    { ifdIdentifier = t
-    , ifdType = TypeLong
-    , ifdCount = 1
-    , ifdOffset = v V.! 0
-    , ifdExtended = ExifNone
-    }
-  | otherwise = ImageFileDirectory
-    { ifdIdentifier = t
-    , ifdType = TypeLong
-    , ifdCount = size
-    , ifdOffset = 0
-    , ifdExtended = d
-    }
-  where size = fromIntegral $ F.length v
-makeIfd t s@(ExifString str) = ImageFileDirectory
-    { ifdIdentifier = t
-    , ifdType = TypeAscii
-    , ifdCount = fromIntegral $ BC.length str
-    , ifdOffset = 0
-    , ifdExtended = s
-    }
-makeIfd t s@(ExifUndefined str)
-  | size > 4 = ImageFileDirectory
-    { ifdIdentifier = t
-    , ifdType = TypeUndefined
-    , ifdCount = size
-    , ifdOffset = 0
-    , ifdExtended = s
-    }
-  | otherwise = ImageFileDirectory
-    { ifdIdentifier = t
-    , ifdType = TypeUndefined
-    , ifdCount = size
-    , ifdOffset = ofs
-    , ifdExtended = ExifNone
-    }
-  where
-    size = fromIntegral $ BC.length str
-    at ix
-      | fromIntegral ix < size = fromIntegral $ B.index str ix `unsafeShiftL` (4 - (8 * ix))
-      | otherwise = 0
-    ofs = at 0 .|. at 1 .|. at 2 .|. at 3
-makeIfd t d = ImageFileDirectory
-  { ifdIdentifier = t
-  , ifdType = typeOfData d
-  , ifdCount = 1
-  , ifdOffset = 0
-  , ifdExtended = d
-  }
-
-encodeTiffStringMetadata :: Metadatas -> [ImageFileDirectory]
-encodeTiffStringMetadata metas = sortBy (compare `on` word16OfTag . ifdIdentifier) $ allTags where
-  keyStr tag k = case Met.lookup k metas of
-    Nothing -> mempty
-    Just v -> pure . makeIfd tag . ExifString $ BC.pack v
-  allTags = copyright <> artist <> title <> description <> software <> allPureExif
-
-  allPureExif = fmap (uncurry makeIfd) $ extractExifMetas metas
-
-  copyright = keyStr TagCopyright Met.Copyright
-  artist = keyStr TagArtist Met.Author
-  title = keyStr TagDocumentName Met.Title
-  description = keyStr TagImageDescription Met.Description
-  software = keyStr TagSoftware Met.Software
-
-extractTiffStringMetadata :: [ImageFileDirectory] -> Metadatas
-extractTiffStringMetadata = Met.insert Met.Format Met.SourceTiff . foldMap go where
-  strMeta k = Met.singleton k . BC.unpack
-  exif ifd =
-    Met.singleton (Met.Exif $ ifdIdentifier ifd) $ ifdExtended ifd
-  inserter acc (k, v) = Met.insert (Met.Exif k) v acc
-  exifShort ifd =
-    Met.singleton (Met.Exif $ ifdIdentifier ifd) . (ExifShort . fromIntegral) $ ifdOffset ifd
-
-  go :: ImageFileDirectory -> Metadatas
-  go ifd = case (ifdIdentifier ifd, ifdExtended ifd) of
-    (TagArtist, ExifString v) -> strMeta Met.Author v
-    (TagBitsPerSample, _) -> mempty
-    (TagColorMap, _) -> mempty
-    (TagCompression, _) -> mempty
-    (TagCopyright, ExifString v) -> strMeta Met.Copyright v
-    (TagDocumentName, ExifString v) -> strMeta Met.Title v
-    (TagExifOffset, ExifIFD lst) -> F.foldl' inserter mempty lst
-    (TagImageDescription, ExifString v) -> strMeta Met.Description v
-    (TagImageLength, _) -> Met.singleton Met.Height . fromIntegral $ ifdOffset ifd
-    (TagImageWidth, _) -> Met.singleton Met.Width . fromIntegral $ ifdOffset ifd
-    (TagJPEGACTables, _) -> mempty
-    (TagJPEGDCTables, _) -> mempty
-    (TagJPEGInterchangeFormat, _) -> mempty
-    (TagJPEGInterchangeFormatLength, _) -> mempty
-    (TagJPEGLosslessPredictors, _) -> mempty
-    (TagJPEGPointTransforms, _) -> mempty
-    (TagJPEGQTables, _) -> mempty
-    (TagJPEGRestartInterval, _) -> mempty
-    (TagJpegProc, _) -> mempty
-    (TagModel, v) -> Met.singleton (Met.Exif TagModel) v
-    (TagMake, v) -> Met.singleton (Met.Exif TagMake) v
-    (TagOrientation, _) -> exifShort ifd
-    (TagResolutionUnit, _) -> mempty
-    (TagRowPerStrip, _) -> mempty
-    (TagSamplesPerPixel, _) -> mempty
-    (TagSoftware, ExifString v) -> strMeta Met.Software v
-    (TagStripByteCounts, _) -> mempty
-    (TagStripOffsets, _) -> mempty
-    (TagTileByteCount, _) -> mempty
-    (TagTileLength, _) -> mempty
-    (TagTileOffset, _) -> mempty
-    (TagTileWidth, _) -> mempty
-    (TagUnknown _, _) -> exif ifd
-    (TagXResolution, _) -> mempty
-    (TagYCbCrCoeff, _) -> mempty
-    (TagYCbCrPositioning, _) -> mempty
-    (TagYCbCrSubsampling, _) -> mempty
-    (TagYResolution, _) -> mempty
-    _ -> mempty
-
-byTag :: ExifTag -> ImageFileDirectory -> Bool
-byTag t ifd = ifdIdentifier ifd == t
-
-data TiffResolutionUnit
-  = ResolutionUnitUnknown
-  | ResolutionUnitInch
-  | ResolutionUnitCentimeter
-
-unitOfIfd :: ImageFileDirectory -> TiffResolutionUnit
-unitOfIfd ifd = case (ifdType ifd, ifdOffset ifd) of
-  (TypeShort, 1) -> ResolutionUnitUnknown
-  (TypeShort, 2) -> ResolutionUnitInch
-  (TypeShort, 3) -> ResolutionUnitCentimeter
-  _ -> ResolutionUnitUnknown
-
-extractTiffDpiMetadata :: [ImageFileDirectory] -> Metadatas
-extractTiffDpiMetadata lst = go where
-  go = case unitOfIfd <$> find (byTag TagResolutionUnit) lst of
-    Nothing -> mempty
-    Just ResolutionUnitUnknown -> mempty
-    Just ResolutionUnitCentimeter -> findDpis Met.dotsPerCentiMeterToDotPerInch mempty
-    Just ResolutionUnitInch -> findDpis id mempty
-
-  findDpis toDpi =
-     findDpi Met.DpiX TagXResolution toDpi . findDpi Met.DpiY TagYResolution toDpi
-
-  findDpi k tag toDpi metas = case find (byTag tag) lst of
-    Nothing -> metas
-    Just ImageFileDirectory { ifdExtended = ExifRational num den } ->
-      Met.insert k (toDpi . fromIntegral $ num `div` den) metas
-    Just _ -> metas
-
-extractTiffMetadata :: [ImageFileDirectory] -> Metadatas
-extractTiffMetadata lst = extractTiffDpiMetadata lst <> extractTiffStringMetadata lst
-
− src/Codec/Picture/Tiff/Types.hs
@@ -1,483 +0,0 @@-{-# LANGUAGE CPP #-}
-{-# LANGUAGE MultiParamTypeClasses #-}
-{-# LANGUAGE FlexibleInstances #-}
-{-# LANGUAGE FlexibleContexts #-}
-module Codec.Picture.Tiff.Types
-    ( BinaryParam( .. )
-    , Endianness( .. )
-    , TiffHeader( .. )
-    , TiffPlanarConfiguration( .. )
-    , TiffCompression( .. )
-    , IfdType( .. )
-    , TiffColorspace( .. )
-    , TiffSampleFormat( .. )
-    , ImageFileDirectory( .. )
-    , ExtraSample( .. )
-    , Predictor( .. )
-
-    , planarConfgOfConstant
-    , constantToPlaneConfiguration
-    , unpackSampleFormat
-    , word16OfTag
-    , unpackPhotometricInterpretation
-    , packPhotometricInterpretation
-    , codeOfExtraSample
-    , unPackCompression
-    , packCompression 
-    , predictorOfConstant
-    ) where
-
-#if !MIN_VERSION_base(4,8,0)
-import Control.Applicative( (<$>), (<*>), pure )
-#endif
-
-import Control.Monad( forM_, when, replicateM, )
-import Data.Bits( (.&.), unsafeShiftR )
-import Data.Binary( Binary( .. ) )
-import Data.Binary.Get( Get
-                      , getWord16le, getWord16be
-                      , getWord32le, getWord32be
-                      , bytesRead
-                      , skip
-                      , getByteString
-                      )
-import Data.Binary.Put( Put
-                      , putWord16le, putWord16be
-                      , putWord32le, putWord32be
-                      , putByteString
-                      )
-import Data.Function( on )
-import Data.List( sortBy, mapAccumL )
-import qualified Data.Vector as V
-import qualified Data.ByteString as B
-import Data.Int( Int32 )
-import Data.Word( Word8, Word16, Word32 )
-
-import Codec.Picture.Metadata.Exif
-{-import Debug.Trace-}
-
-data Endianness
-  = EndianLittle
-  | EndianBig
-  deriving (Eq, Show)
-
-instance Binary Endianness where
-  put EndianLittle = putWord16le 0x4949
-  put EndianBig = putWord16le 0x4D4D
-
-  get = do
-    tag <- getWord16le
-    case tag of
-      0x4949 -> return EndianLittle
-      0x4D4D -> return EndianBig
-      _ -> fail "Invalid endian tag value"
-
--- | Because having a polymorphic get with endianness is to nice
--- to pass on, introducing this helper type class, which is just
--- a superset of Binary, but formalising a parameter passing
--- into it.
-class BinaryParam a b where
-  getP :: a -> Get b
-  putP :: a -> b -> Put
-
-data TiffHeader = TiffHeader
-  { hdrEndianness :: !Endianness
-  , hdrOffset     :: {-# UNPACK #-} !Word32
-  }
-  deriving (Eq, Show)
-
-instance BinaryParam Endianness Word16 where
-  putP EndianLittle = putWord16le
-  putP EndianBig = putWord16be
-
-  getP EndianLittle = getWord16le
-  getP EndianBig = getWord16be
-
-instance BinaryParam Endianness Int32 where
-  putP en v = putP en $ (fromIntegral v :: Word32)
-  getP en = fromIntegral <$> (getP en :: Get Word32) 
-
-instance BinaryParam Endianness Word32 where
-  putP EndianLittle = putWord32le
-  putP EndianBig = putWord32be
-
-  getP EndianLittle = getWord32le
-  getP EndianBig = getWord32be
-
-instance Binary TiffHeader where
-  put hdr = do
-    let endian = hdrEndianness hdr
-    put endian
-    putP endian (42 :: Word16)
-    putP endian $ hdrOffset hdr
-
-  get = do
-    endian <- get
-    magic <- getP endian
-    let magicValue = 42 :: Word16
-    when (magic /= magicValue)
-         (fail "Invalid TIFF magic number")
-    TiffHeader endian <$> getP endian
-
-data TiffPlanarConfiguration
-  = PlanarConfigContig    -- = 1
-  | PlanarConfigSeparate  -- = 2
-
-planarConfgOfConstant :: Word32 -> Get TiffPlanarConfiguration
-planarConfgOfConstant 0 = pure PlanarConfigContig
-planarConfgOfConstant 1 = pure PlanarConfigContig
-planarConfgOfConstant 2 = pure PlanarConfigSeparate
-planarConfgOfConstant v = fail $ "Unknown planar constant (" ++ show v ++ ")"
-
-constantToPlaneConfiguration :: TiffPlanarConfiguration -> Word16
-constantToPlaneConfiguration PlanarConfigContig = 1
-constantToPlaneConfiguration PlanarConfigSeparate = 2
-
-data TiffCompression
-  = CompressionNone           -- 1
-  | CompressionModifiedRLE    -- 2
-  | CompressionLZW            -- 5
-  | CompressionJPEG           -- 6
-  | CompressionPackBit        -- 32273
-
-data IfdType
-  = TypeByte
-  | TypeAscii
-  | TypeShort
-  | TypeLong
-  | TypeRational
-  | TypeSByte
-  | TypeUndefined
-  | TypeSignedShort
-  | TypeSignedLong
-  | TypeSignedRational
-  | TypeFloat
-  | TypeDouble
-  deriving Show
-
-instance BinaryParam Endianness IfdType where
-    getP endianness = getP endianness >>= conv where
-      conv :: Word16 -> Get IfdType
-      conv v = case v of
-        1  -> return TypeByte
-        2  -> return TypeAscii
-        3  -> return TypeShort
-        4  -> return TypeLong
-        5  -> return TypeRational
-        6  -> return TypeSByte
-        7  -> return TypeUndefined
-        8  -> return TypeSignedShort
-        9  -> return TypeSignedLong
-        10 -> return TypeSignedRational
-        11 -> return TypeFloat
-        12 -> return TypeDouble
-        _  -> fail "Invalid TIF directory type"
-
-    putP endianness = putP endianness . conv where
-      conv :: IfdType -> Word16
-      conv v = case v of
-        TypeByte -> 1
-        TypeAscii -> 2
-        TypeShort -> 3
-        TypeLong -> 4
-        TypeRational -> 5
-        TypeSByte -> 6
-        TypeUndefined -> 7
-        TypeSignedShort -> 8
-        TypeSignedLong -> 9
-        TypeSignedRational -> 10
-        TypeFloat -> 11
-        TypeDouble -> 12
-
-instance BinaryParam Endianness ExifTag where
-  getP endianness = tagOfWord16 <$> getP endianness
-  putP endianness = putP endianness . word16OfTag
-
-data Predictor
-  = PredictorNone                   -- 1
-  | PredictorHorizontalDifferencing -- 2
-  deriving Eq
-
-predictorOfConstant :: Word32 -> Get Predictor
-predictorOfConstant 1 = pure PredictorNone
-predictorOfConstant 2 = pure PredictorHorizontalDifferencing
-predictorOfConstant v = fail $ "Unknown predictor (" ++ show v ++ ")"
-
-paddWrite :: B.ByteString -> Put
-paddWrite str = putByteString str >> padding where
-  zero = 0 :: Word8
-  padding = when (odd (B.length str)) $ put zero
-
-instance BinaryParam (Endianness, Int, ImageFileDirectory) ExifData where
-  putP (endianness, _, _) = dump
-    where
-      dump ExifNone = pure ()
-      dump (ExifLong _) = pure ()
-      dump (ExifShort _) = pure ()
-      dump (ExifIFD _) = pure ()
-      dump (ExifString bstr) = paddWrite bstr
-      dump (ExifUndefined bstr) = paddWrite bstr
-      -- wrong if length == 2
-      dump (ExifShorts shorts) = V.mapM_ (putP endianness) shorts
-      dump (ExifLongs longs) = V.mapM_ (putP endianness) longs
-      dump (ExifRational a b) = putP endianness a >> putP endianness b
-      dump (ExifSignedRational a b) = putP endianness a >> putP endianness b
-
-  getP (endianness, maxi, ifd) = fetcher ifd
-    where
-      align ImageFileDirectory { ifdOffset = offset } act = do
-        readed <- bytesRead
-        let delta = fromIntegral offset - readed
-        if offset >= fromIntegral maxi || fromIntegral readed > offset then
-          pure ExifNone
-        else do
-          skip $ fromIntegral delta
-          act
-
-      getE :: (BinaryParam Endianness a) => Get a
-      getE = getP endianness
-
-      getVec count = V.replicateM (fromIntegral count)
-
-      fetcher ImageFileDirectory { ifdIdentifier = TagExifOffset
-                                 , ifdType = TypeLong
-                                 , ifdCount = 1 } = do
-         align ifd $ do
-            let byOffset = sortBy (compare `on` ifdOffset)
-                cleansIfds = fmap (cleanImageFileDirectory endianness)
-            subIfds <- cleansIfds . byOffset <$> getP endianness
-            cleaned <- fetchExtended endianness maxi $ sortBy (compare `on` ifdOffset) subIfds
-            pure $ ExifIFD [(ifdIdentifier fd, ifdExtended fd) | fd <- cleaned]
-         {-  
-      fetcher ImageFileDirectory { ifdIdentifier = TagGPSInfo
-                                 , ifdType = TypeLong
-                                 , ifdCount = 1 } = do
-         align ifd 
-         subIfds <- fmap (cleanImageFileDirectory endianness) <$> getP endianness
-         cleaned <- fetchExtended endianness subIfds
-         pure $ ExifIFD [(ifdIdentifier fd, ifdExtended fd) | fd <- cleaned]
-        -}
-      fetcher ImageFileDirectory { ifdType = TypeUndefined, ifdCount = count } | count > 4 =
-         align ifd $ ExifUndefined <$> getByteString (fromIntegral count)
-      fetcher ImageFileDirectory { ifdType = TypeUndefined, ifdOffset = ofs } =
-          pure . ExifUndefined . B.pack $ take (fromIntegral $ ifdCount ifd)
-              [fromIntegral $ ofs .&. 0xFF000000 `unsafeShiftR` (3 * 8)
-              ,fromIntegral $ ofs .&. 0x00FF0000 `unsafeShiftR` (2 * 8)
-              ,fromIntegral $ ofs .&. 0x0000FF00 `unsafeShiftR` (1 * 8)
-              ,fromIntegral $ ofs .&. 0x000000FF
-              ]
-      fetcher ImageFileDirectory { ifdType = TypeAscii, ifdCount = count } | count > 1 =
-          align ifd $ ExifString <$> getByteString (fromIntegral count)
-      fetcher ImageFileDirectory { ifdType = TypeShort, ifdCount = 2, ifdOffset = ofs } =
-          pure . ExifShorts $ V.fromListN 2 valList
-            where high = fromIntegral $ ofs `unsafeShiftR` 16
-                  low = fromIntegral $ ofs .&. 0xFFFF
-                  valList = case endianness of
-                    EndianLittle -> [low, high]
-                    EndianBig -> [high, low]
-      fetcher ImageFileDirectory { ifdType = TypeRational, ifdCount = 1 } = do
-          align ifd $ ExifRational <$> getP EndianLittle <*> getP EndianLittle
-      fetcher ImageFileDirectory { ifdType = TypeSignedRational, ifdCount = 1 } = do
-          align ifd $ ExifSignedRational <$> getP EndianLittle <*> getP EndianLittle
-      fetcher ImageFileDirectory { ifdType = TypeShort, ifdCount = 1 } =
-          pure . ExifShort . fromIntegral $ ifdOffset ifd
-      fetcher ImageFileDirectory { ifdType = TypeShort, ifdCount = count } | count > 2 =
-          align ifd $ ExifShorts <$> getVec count getE
-      fetcher ImageFileDirectory { ifdType = TypeLong, ifdCount = 1 } =
-          pure . ExifLong . fromIntegral $ ifdOffset ifd
-      fetcher ImageFileDirectory { ifdType = TypeLong, ifdCount = count } | count > 1 =
-          align ifd $ ExifLongs <$> getVec count getE
-      fetcher _ = pure ExifNone
-
-cleanImageFileDirectory :: Endianness -> ImageFileDirectory -> ImageFileDirectory
-cleanImageFileDirectory EndianBig ifd@(ImageFileDirectory { ifdCount = 1 }) = aux $ ifdType ifd
-  where
-    aux TypeShort = ifd { ifdOffset = ifdOffset ifd `unsafeShiftR` 16 }
-    aux _ = ifd
-cleanImageFileDirectory _ ifd = ifd
-
-fetchExtended :: Endianness -> Int -> [ImageFileDirectory] -> Get [ImageFileDirectory]
-fetchExtended endian maxi = mapM $ \ifd -> do
-  v <- getP (endian, maxi, ifd)
-  pure $ ifd { ifdExtended = v }
-
--- | All the IFD must be written in order according to the tag
--- value of the IFD. To avoid getting to much restriction in the
--- serialization code, just sort it.
-orderIfdByTag :: [ImageFileDirectory] -> [ImageFileDirectory]
-orderIfdByTag = sortBy comparer where
-  comparer a b = compare t1 t2 where
-    t1 = word16OfTag $ ifdIdentifier a
-    t2 = word16OfTag $ ifdIdentifier b
-
--- | Given an official offset and a list of IFD, update the offset information
--- of the IFD with extended data.
-setupIfdOffsets :: Word32 -> [ImageFileDirectory] -> (Word32, [ImageFileDirectory])
-setupIfdOffsets initialOffset lst = mapAccumL updater startExtended lst
-  where ifdElementCount = fromIntegral $ length lst
-        ifdSize = 12
-        ifdCountSize = 2
-        nextOffsetSize = 4
-        startExtended = initialOffset
-                     + ifdElementCount * ifdSize
-                     + ifdCountSize + nextOffsetSize
-
-        paddedSize blob = fromIntegral $ blobLength + padding where
-          blobLength = B.length blob
-          padding = if odd blobLength then 1 else 0
-
-        updater ix ifd@(ImageFileDirectory { ifdIdentifier = TagExifOffset }) =
-            (ix, ifd { ifdOffset = ix } )
-        updater ix ifd@(ImageFileDirectory { ifdExtended = ExifUndefined b }) =
-            (ix + paddedSize b, ifd { ifdOffset = ix } )
-        updater ix ifd@(ImageFileDirectory { ifdExtended = ExifString b }) =
-            (ix + paddedSize b, ifd { ifdOffset = ix } )
-        updater ix ifd@(ImageFileDirectory { ifdExtended = ExifLongs v })
-            | V.length v > 1 = ( ix + fromIntegral (V.length v * 4)
-                               , ifd { ifdOffset = ix } )
-        updater ix ifd@(ImageFileDirectory { ifdExtended = ExifShorts v })
-            | V.length v > 2 = ( ix + fromIntegral (V.length v * 2)
-                             , ifd { ifdOffset = ix })
-        updater ix ifd = (ix, ifd)
-
-instance BinaryParam B.ByteString (TiffHeader, [[ImageFileDirectory]]) where
-  putP rawData (hdr, ifds) = do
-    put hdr
-    putByteString rawData
-    let endianness = hdrEndianness hdr
-        (_, offseted) = mapAccumL
-            (\ix ifd -> setupIfdOffsets ix $ orderIfdByTag ifd)
-            (hdrOffset hdr)
-            ifds
-    forM_ offseted $ \list -> do
-        putP endianness list
-        mapM_ (\field -> putP (endianness, (0::Int), field) $ ifdExtended field) list
-
-  getP raw = do
-    hdr <- get
-    readed <- bytesRead
-    skip . fromIntegral $ fromIntegral (hdrOffset hdr) - readed
-    let endian = hdrEndianness hdr
-        byOffset = sortBy (compare `on` ifdOffset)
-        cleanIfds = fmap (cleanImageFileDirectory endian)
-
-    ifd <-  cleanIfds . byOffset <$> getP endian
-    cleaned <- fetchExtended endian (B.length raw) ifd
-    return (hdr, [cleaned])
-
-data TiffSampleFormat
-  = TiffSampleUint
-  | TiffSampleInt
-  | TiffSampleDouble
-  | TiffSampleUnknown
-  deriving Eq
-
-unpackSampleFormat :: Word32 -> Get TiffSampleFormat
-unpackSampleFormat v = case v of
-  1 -> pure TiffSampleUint
-  2 -> pure TiffSampleInt
-  3 -> pure TiffSampleDouble
-  4 -> pure TiffSampleUnknown
-  vv -> fail $ "Undefined data format (" ++ show vv ++ ")"
-
-data ImageFileDirectory = ImageFileDirectory
-  { ifdIdentifier :: !ExifTag -- Word16
-  , ifdType       :: !IfdType -- Word16
-  , ifdCount      :: !Word32
-  , ifdOffset     :: !Word32
-  , ifdExtended   :: !ExifData
-  }
-  deriving Show
-
-instance BinaryParam Endianness ImageFileDirectory where
-  getP endianness =
-    ImageFileDirectory <$> getE <*> getE <*> getE <*> getE
-                       <*> pure ExifNone
-        where getE :: (BinaryParam Endianness a) => Get a
-              getE = getP endianness
-
-  putP endianness ifd = do
-    let putE :: (BinaryParam Endianness a) => a -> Put
-        putE = putP endianness
-    putE $ ifdIdentifier ifd
-    putE $ ifdType ifd
-    putE $ ifdCount ifd
-    putE $ ifdOffset ifd
-
-instance BinaryParam Endianness [ImageFileDirectory] where
-  getP endianness = do
-    count <- getP endianness :: Get Word16
-    rez <- replicateM (fromIntegral count) $ getP endianness
-    _ <- getP endianness :: Get Word32
-    pure rez
-
-
-  putP endianness lst = do
-    let count = fromIntegral $ length lst :: Word16
-    putP endianness count
-    mapM_ (putP endianness) lst
-    putP endianness (0 :: Word32)
-
-data TiffColorspace
-  = TiffMonochromeWhite0 -- ^ 0
-  | TiffMonochrome       -- ^ 1
-  | TiffRGB              -- ^ 2
-  | TiffPaleted          -- ^ 3
-  | TiffTransparencyMask -- ^ 4
-  | TiffCMYK             -- ^ 5
-  | TiffYCbCr            -- ^ 6
-  | TiffCIELab           -- ^ 8
-
-
-packPhotometricInterpretation :: TiffColorspace -> Word16
-packPhotometricInterpretation v = case v of
-  TiffMonochromeWhite0 -> 0
-  TiffMonochrome       -> 1
-  TiffRGB              -> 2
-  TiffPaleted          -> 3
-  TiffTransparencyMask -> 4
-  TiffCMYK             -> 5
-  TiffYCbCr            -> 6
-  TiffCIELab           -> 8
-
-unpackPhotometricInterpretation :: Word32 -> Get TiffColorspace
-unpackPhotometricInterpretation v = case v of
-  0 -> pure TiffMonochromeWhite0
-  1 -> pure TiffMonochrome
-  2 -> pure TiffRGB
-  3 -> pure TiffPaleted
-  4 -> pure TiffTransparencyMask
-  5 -> pure TiffCMYK
-  6 -> pure TiffYCbCr
-  8 -> pure TiffCIELab
-  vv -> fail $ "Unrecognized color space " ++ show vv
-
-data ExtraSample
-  = ExtraSampleUnspecified       -- ^ 0
-  | ExtraSampleAssociatedAlpha   -- ^ 1
-  | ExtraSampleUnassociatedAlpha -- ^ 2
-
-codeOfExtraSample :: ExtraSample -> Word16
-codeOfExtraSample v = case v of
-  ExtraSampleUnspecified -> 0
-  ExtraSampleAssociatedAlpha -> 1
-  ExtraSampleUnassociatedAlpha -> 2
-
-unPackCompression :: Word32 -> Get TiffCompression
-unPackCompression v = case v of
-  0 -> pure CompressionNone
-  1 -> pure CompressionNone
-  2 -> pure CompressionModifiedRLE
-  5 -> pure CompressionLZW
-  6 -> pure CompressionJPEG
-  32773 -> pure CompressionPackBit
-  vv -> fail $ "Unknown compression scheme " ++ show vv
-
-packCompression :: TiffCompression -> Word16
-packCompression v = case v of
-  CompressionNone        -> 1
-  CompressionModifiedRLE -> 2
-  CompressionLZW         -> 5
-  CompressionJPEG        -> 6
-  CompressionPackBit     -> 32773
-
src/Codec/Picture/Types.hs view
@@ -1,15 +1,17 @@-{-# LANGUAGE MultiParamTypeClasses #-}
-{-# LANGUAGE FlexibleInstances #-}
-{-# LANGUAGE ScopedTypeVariables #-}
-{-# LANGUAGE TypeSynonymInstances #-}
-{-# LANGUAGE FunctionalDependencies #-}
-{-# LANGUAGE TypeFamilies #-}
-{-# LANGUAGE FlexibleContexts #-}
-{-# LANGUAGE Rank2Types #-}
-{-# LANGUAGE BangPatterns #-}
-{-# LANGUAGE CPP #-}
-{-# LANGUAGE DeriveDataTypeable #-}
 -- | Module provides basic types for image manipulation in the library.
+
+{-# LANGUAGE BangPatterns           #-}
+{-# LANGUAGE CPP                    #-}
+{-# LANGUAGE DeriveDataTypeable     #-}
+{-# LANGUAGE FlexibleContexts       #-}
+{-# LANGUAGE FlexibleInstances      #-}
+{-# LANGUAGE FunctionalDependencies #-}
+{-# LANGUAGE MultiParamTypeClasses  #-}
+{-# LANGUAGE Rank2Types             #-}
+{-# LANGUAGE ScopedTypeVariables    #-}
+{-# LANGUAGE TypeFamilies           #-}
+{-# LANGUAGE TypeSynonymInstances   #-}
+{-# LANGUAGE UndecidableInstances   #-}
 -- Defined types are used to store all of those __Juicy Pixels__
 module Codec.Picture.Types( -- * Types
                             -- ** Image types
@@ -107,8 +109,9 @@ import Data.Monoid( Monoid, mempty )
 import Control.Applicative( Applicative, pure, (<*>), (<$>) )
 #endif
-
+#if !MIN_VERSION_base(4,11,0)
 import Data.Monoid( (<>) )
+#endif
 import Control.Monad( foldM, liftM, ap )
 import Control.DeepSeq( NFData( .. ) )
 import Control.Monad.ST( ST, runST )
@@ -153,6 +156,12 @@     }
     deriving (Typeable)
 
+instance (Eq (PixelBaseComponent a), Storable (PixelBaseComponent a))
+    => Eq (Image a) where
+  a == b = imageWidth  a == imageWidth  b &&
+           imageHeight a == imageHeight b &&
+           imageData   a == imageData   b
+
 -- | Type for the palette used in Gif & PNG files.
 type Palette = Image PixelRGB8
 
@@ -369,6 +378,8 @@        ImageY8    (Image Pixel8)
        -- | A greyscale image with 16bit components
      | ImageY16   (Image Pixel16)
+       -- | A greyscale image with 32bit components
+     | ImageY32   (Image Pixel32)
        -- | A greyscale HDR image
      | ImageYF    (Image PixelF)
        -- | An image in greyscale with an alpha channel.
@@ -391,10 +402,10 @@      | ImageCMYK8  (Image PixelCMYK8)
        -- | An image in the colorspace CMYK and 16 bits precision
      | ImageCMYK16 (Image PixelCMYK16)
-    deriving (Typeable)
+    deriving (Eq, Typeable)
 
 -- | Type used to expose a palette extracted during reading.
--- Use palettedAsImage to convert it to a palette usable for
+-- Use `palettedAsImage` to convert it to a palette usable for
 -- writing.
 data Palette' px = Palette'
   { -- | Number of element in pixels.
@@ -442,6 +453,7 @@            -> DynamicImage -> a
 dynamicMap f (ImageY8    i) = f i
 dynamicMap f (ImageY16   i) = f i
+dynamicMap f (ImageY32   i) = f i
 dynamicMap f (ImageYF    i) = f i
 dynamicMap f (ImageYA8   i) = f i
 dynamicMap f (ImageYA16  i) = f i
@@ -474,6 +486,7 @@   where
     aux (ImageY8    i) = ImageY8 (f i)
     aux (ImageY16   i) = ImageY16 (f i)
+    aux (ImageY32   i) = ImageY32 (f i)
     aux (ImageYF    i) = ImageYF (f i)
     aux (ImageYA8   i) = ImageYA8 (f i)
     aux (ImageYA16  i) = ImageYA16 (f i)
@@ -489,6 +502,7 @@ instance NFData DynamicImage where
     rnf (ImageY8 img)     = rnf img
     rnf (ImageY16 img)    = rnf img
+    rnf (ImageY32 img)    = rnf img
     rnf (ImageYF img)     = rnf img
     rnf (ImageYA8 img)    = rnf img
     rnf (ImageYA16 img)   = rnf img
@@ -1234,6 +1248,10 @@     {-# INLINE promotePixel #-}
     promotePixel c = PixelRGB8 c c c
 
+instance ColorConvertible Pixel8 PixelRGB16 where
+    {-# INLINE promotePixel #-}
+    promotePixel c = PixelRGB16 (fromIntegral c * 257) (fromIntegral c * 257) (fromIntegral c * 257)
+
 instance ColorConvertible Pixel8 PixelRGBA8 where
     {-# INLINE promotePixel #-}
     promotePixel c = PixelRGBA8 c c c 255
@@ -1410,6 +1428,10 @@     {-# INLINE promotePixel #-}
     promotePixel (PixelYA8 y _) = PixelRGB8 y y y
 
+instance ColorConvertible PixelYA8 PixelRGB16 where
+    {-# INLINE promotePixel #-}
+    promotePixel (PixelYA8 y _) = PixelRGB16 (fromIntegral y * 257) (fromIntegral y * 257) (fromIntegral y * 257)
+
 instance ColorConvertible PixelYA8 PixelRGBA8 where
     {-# INLINE promotePixel #-}
     promotePixel (PixelYA8 y a) = PixelRGBA8 y y y a
@@ -1480,6 +1502,10 @@     unsafeWritePixel v idx (PixelYA16 y a) =
         M.unsafeWrite v idx y >> M.unsafeWrite v (idx + 1) a
 
+instance ColorConvertible PixelYA16 PixelRGB16 where
+    {-# INLINE promotePixel #-}
+    promotePixel (PixelYA16 y _) = PixelRGB16 y y y
+
 instance ColorConvertible PixelYA16 PixelRGBA16 where
     {-# INLINE promotePixel #-}
     promotePixel (PixelYA16 y a) = PixelRGBA16 y y y a
@@ -2230,26 +2256,25 @@                                  -> (Word8, Word8, Word8) -> b #-}
 {-# SPECIALIZE integralRGBToCMYK :: (Word16 -> Word16 -> Word16 -> Word16 -> b)
                                  -> (Word16, Word16, Word16) -> b #-}
+-- | Convert RGB8 or RGB16 to CMYK8 and CMYK16 respectfully.
+--
+-- /Note/ - 32bit precision is not supported. Make sure to adjust implementation if ever
+-- used with Word32.
 integralRGBToCMYK :: (Bounded a, Integral a)
                   => (a -> a -> a -> a -> b)    -- ^ Pixel building function
                   -> (a, a, a)                  -- ^ RGB sample
                   -> b                          -- ^ Resulting sample
-integralRGBToCMYK build (r, g, b) =
-  build (clamp c) (clamp m) (clamp y) (fromIntegral kInt)
-    where maxi = maxBound
-
-          ir = fromIntegral $ maxi - r :: Int
-          ig = fromIntegral $ maxi - g
-          ib = fromIntegral $ maxi - b
-
-          kInt = minimum [ir, ig, ib]
-          ik = fromIntegral maxi - kInt
-
-          c = (ir - kInt) `div` ik
-          m = (ig - kInt) `div` ik
-          y = (ib - kInt) `div` ik
-
-          clamp = fromIntegral . max 0
+integralRGBToCMYK build (r, g, b)
+  | kMax == 0 = build 0 0 0 maxVal -- prevent division by zero
+  | otherwise = build (fromIntegral c) (fromIntegral m) (fromIntegral y) k
+    where maxVal = maxBound
+          max32 = fromIntegral maxVal :: Word32
+          kMax32 = fromIntegral kMax :: Word32
+          kMax = max r (max g b)
+          k = maxVal - kMax
+          c = max32 * (kMax32 - fromIntegral r) `div` kMax32
+          m = max32 * (kMax32 - fromIntegral g) `div` kMax32
+          y = max32 * (kMax32 - fromIntegral b) `div` kMax32
 
 instance ColorSpaceConvertible PixelRGB8 PixelCMYK8 where
   convertPixel (PixelRGB8 r g b) = integralRGBToCMYK PixelCMYK8 (r, g, b)
src/Codec/Picture/VectorByteConversion.hs view
@@ -1,45 +1,52 @@-{-# LANGUAGE ScopedTypeVariables #-}-{-# LANGUAGE TypeFamilies #-}-{-# LANGUAGE CPP #-}-module Codec.Picture.VectorByteConversion( blitVector-                                         , toByteString-                                         , imageFromUnsafePtr ) where--import Data.Word( Word8 )-import Data.Vector.Storable( Vector, unsafeToForeignPtr, unsafeFromForeignPtr0 )-import Foreign.Storable( Storable, sizeOf )--#if !MIN_VERSION_base(4,8,0)-import Foreign.ForeignPtr.Safe( ForeignPtr, castForeignPtr )-#else-import Foreign.ForeignPtr( ForeignPtr, castForeignPtr )-#endif---import qualified Data.ByteString as B-import qualified Data.ByteString.Internal as S--import Codec.Picture.Types--blitVector :: Vector Word8 -> Int -> Int -> B.ByteString-blitVector vec atIndex = S.PS ptr (offset + atIndex)-  where (ptr, offset, _length) = unsafeToForeignPtr vec--toByteString :: forall a. (Storable a) => Vector a -> B.ByteString-toByteString vec = S.PS (castForeignPtr ptr) offset (len * size)-  where (ptr, offset, len) = unsafeToForeignPtr vec-        size = sizeOf (undefined :: a)---- | Import a image from an unsafe pointer--- The pointer must have a size of width * height * componentCount px-imageFromUnsafePtr :: forall px-                    . (Pixel px, (PixelBaseComponent px) ~ Word8)-                   => Int -- ^ Width in pixels-                   -> Int -- ^ Height in pixels-                   -> ForeignPtr Word8 -- ^ Pointer to the raw data-                   -> Image px-imageFromUnsafePtr width height ptr =-    Image width height $ unsafeFromForeignPtr0 ptr size-      where compCount = componentCount (undefined :: px)-            size = width * height * compCount-+{-# LANGUAGE ScopedTypeVariables #-}
+{-# LANGUAGE TypeFamilies #-}
+{-# LANGUAGE CPP #-}
+module Codec.Picture.VectorByteConversion( blitVector
+                                         , toByteString
+                                         , imageFromUnsafePtr ) where
+
+import Data.Word( Word8 )
+import Data.Vector.Storable( Vector, unsafeToForeignPtr, unsafeFromForeignPtr0 )
+import Foreign.Storable( Storable, sizeOf )
+
+#if !MIN_VERSION_base(4,8,0)
+import Foreign.ForeignPtr.Safe( ForeignPtr, castForeignPtr )
+#else
+import Foreign.ForeignPtr( ForeignPtr, castForeignPtr )
+#endif
+
+
+import qualified Data.ByteString as B
+import qualified Data.ByteString.Internal as S
+
+import Codec.Picture.Types
+
+mkBS :: ForeignPtr Word8 -> Int -> Int -> S.ByteString
+#if MIN_VERSION_bytestring(0,11,0)
+mkBS fptr off = S.BS (fptr `S.plusForeignPtr` off)
+#else
+mkBS = S.PS
+#endif
+
+blitVector :: Vector Word8 -> Int -> Int -> B.ByteString
+blitVector vec atIndex = mkBS ptr (offset + atIndex)
+  where (ptr, offset, _length) = unsafeToForeignPtr vec
+
+toByteString :: forall a. (Storable a) => Vector a -> B.ByteString
+toByteString vec = mkBS (castForeignPtr ptr) offset (len * size)
+  where (ptr, offset, len) = unsafeToForeignPtr vec
+        size = sizeOf (undefined :: a)
+
+-- | Import a image from an unsafe pointer
+-- The pointer must have a size of width * height * componentCount px
+imageFromUnsafePtr :: forall px
+                    . (Pixel px, (PixelBaseComponent px) ~ Word8)
+                   => Int -- ^ Width in pixels
+                   -> Int -- ^ Height in pixels
+                   -> ForeignPtr Word8 -- ^ Pointer to the raw data
+                   -> Image px
+imageFromUnsafePtr width height ptr =
+    Image width height $ unsafeFromForeignPtr0 ptr size
+      where compCount = componentCount (undefined :: px)
+            size = width * height * compCount
+