binary-0.8.3.0: src/Data/Binary/Class.hs
{-# LANGUAGE CPP, FlexibleContexts #-}
#if __GLASGOW_HASKELL__ >= 701 && __GLASGOW_HASKELL__ != 702
{-# LANGUAGE Safe #-}
#endif
#ifdef GENERICS
{-# LANGUAGE DefaultSignatures #-}
#endif
#if MIN_VERSION_base(4,8,0)
#define HAS_NATURAL
#define HAS_VOID
#endif
#if MIN_VERSION_base(4,7,0)
#define HAS_FIXED_CONSTRUCTOR
#endif
#if __GLASGOW_HASKELL__ >= 704
#define HAS_GHC_FINGERPRINT
#endif
#ifndef HAS_FIXED_CONSTRUCTOR
{-# LANGUAGE ScopedTypeVariables #-}
#endif
-----------------------------------------------------------------------------
-- |
-- Module : Data.Binary.Class
-- Copyright : Lennart Kolmodin
-- License : BSD3-style (see LICENSE)
--
-- Maintainer : Lennart Kolmodin <kolmodin@gmail.com>
-- Stability : unstable
-- Portability : portable to Hugs and GHC. Requires the FFI and some flexible instances
--
-- Typeclass and instances for binary serialization.
--
-----------------------------------------------------------------------------
module Data.Binary.Class (
-- * The Binary class
Binary(..)
#ifdef GENERICS
-- * Support for generics
, GBinaryGet(..)
, GBinaryPut(..)
#endif
) where
import Data.Word
import Data.Bits
import Data.Int
import Data.Complex (Complex(..))
#ifdef HAS_VOID
import Data.Void
#endif
import Data.Binary.Put
import Data.Binary.Get
#if ! MIN_VERSION_base(4,8,0)
import Control.Applicative
import Data.Monoid (mempty)
#endif
import Data.Monoid ((<>))
import Control.Monad
import Data.ByteString.Lazy (ByteString)
import qualified Data.ByteString.Lazy as L
import qualified Data.ByteString.Builder.Prim as Prim
import Data.List (unfoldr, foldl')
-- And needed for the instances:
import qualified Data.ByteString as B
#if MIN_VERSION_bytestring(0,10,4)
import qualified Data.ByteString.Short as BS
#endif
import qualified Data.Map as Map
import qualified Data.Set as Set
import qualified Data.IntMap as IntMap
import qualified Data.IntSet as IntSet
import qualified Data.Ratio as R
import qualified Data.Tree as T
import Data.Array.Unboxed
#ifdef GENERICS
import GHC.Generics
#endif
#ifdef HAS_NATURAL
import Numeric.Natural
#endif
import qualified Data.Fixed as Fixed
--
-- This isn't available in older Hugs or older GHC
--
#if __GLASGOW_HASKELL__ >= 606
import qualified Data.Sequence as Seq
import qualified Data.Foldable as Fold
#endif
#ifdef HAS_GHC_FINGERPRINT
import GHC.Fingerprint
#endif
import Data.Version (Version(..))
------------------------------------------------------------------------
#ifdef GENERICS
-- Factored into two classes because this makes GHC optimize the
-- instances faster. This doesn't matter for builds of binary,
-- but it matters a lot for end-users who write 'instance Binary T'.
-- See also: https://ghc.haskell.org/trac/ghc/ticket/9630
class GBinaryPut f where
gput :: f t -> Put
class GBinaryGet f where
gget :: Get (f t)
#endif
-- | The 'Binary' class provides 'put' and 'get', methods to encode and
-- decode a Haskell value to a lazy 'ByteString'. It mirrors the 'Read' and
-- 'Show' classes for textual representation of Haskell types, and is
-- suitable for serialising Haskell values to disk, over the network.
--
-- For decoding and generating simple external binary formats (e.g. C
-- structures), Binary may be used, but in general is not suitable
-- for complex protocols. Instead use the 'Put' and 'Get' primitives
-- directly.
--
-- Instances of Binary should satisfy the following property:
--
-- > decode . encode == id
--
-- That is, the 'get' and 'put' methods should be the inverse of each
-- other. A range of instances are provided for basic Haskell types.
--
class Binary t where
-- | Encode a value in the Put monad.
put :: t -> Put
-- | Decode a value in the Get monad
get :: Get t
-- | Encode a list of values in the Put monad.
-- The default implementation may be overridden to be more efficient
-- but must still have the same encoding format.
putList :: [t] -> Put
putList = defaultPutList
#ifdef GENERICS
default put :: (Generic t, GBinaryPut (Rep t)) => t -> Put
put = gput . from
default get :: (Generic t, GBinaryGet (Rep t)) => Get t
get = to `fmap` gget
#endif
{-# INLINE defaultPutList #-}
defaultPutList :: Binary a => [a] -> Put
defaultPutList xs = put (length xs) <> mapM_ put xs
------------------------------------------------------------------------
-- Simple instances
#ifdef HAS_VOID
-- Void never gets written nor reconstructed since it's impossible to have a
-- value of that type
-- | /Since: 0.8.0.0/
instance Binary Void where
put = absurd
get = mzero
#endif
-- The () type need never be written to disk: values of singleton type
-- can be reconstructed from the type alone
instance Binary () where
put () = mempty
get = return ()
-- Bools are encoded as a byte in the range 0 .. 1
instance Binary Bool where
put = putWord8 . fromIntegral . fromEnum
get = getWord8 >>= toBool
where
toBool 0 = return False
toBool 1 = return True
toBool c = fail ("Could not map value " ++ show c ++ " to Bool")
-- Values of type 'Ordering' are encoded as a byte in the range 0 .. 2
instance Binary Ordering where
put = putWord8 . fromIntegral . fromEnum
get = getWord8 >>= toOrd
where
toOrd 0 = return LT
toOrd 1 = return EQ
toOrd 2 = return GT
toOrd c = fail ("Could not map value " ++ show c ++ " to Ordering")
------------------------------------------------------------------------
-- Words and Ints
-- Words8s are written as bytes
instance Binary Word8 where
put = putWord8
{-# INLINE putList #-}
putList xs =
put (length xs)
<> putBuilder (Prim.primMapListFixed Prim.word8 xs)
get = getWord8
-- Words16s are written as 2 bytes in big-endian (network) order
instance Binary Word16 where
put = putWord16be
{-# INLINE putList #-}
putList xs =
put (length xs)
<> putBuilder (Prim.primMapListFixed Prim.word16BE xs)
get = getWord16be
-- Words32s are written as 4 bytes in big-endian (network) order
instance Binary Word32 where
put = putWord32be
{-# INLINE putList #-}
putList xs =
put (length xs)
<> putBuilder (Prim.primMapListFixed Prim.word32BE xs)
get = getWord32be
-- Words64s are written as 8 bytes in big-endian (network) order
instance Binary Word64 where
put = putWord64be
{-# INLINE putList #-}
putList xs =
put (length xs)
<> putBuilder (Prim.primMapListFixed Prim.word64BE xs)
get = getWord64be
-- Int8s are written as a single byte.
instance Binary Int8 where
put = putInt8
{-# INLINE putList #-}
putList xs =
put (length xs)
<> putBuilder (Prim.primMapListFixed Prim.int8 xs)
get = getInt8
-- Int16s are written as a 2 bytes in big endian format
instance Binary Int16 where
put = putInt16be
{-# INLINE putList #-}
putList xs =
put (length xs)
<> putBuilder (Prim.primMapListFixed Prim.int16BE xs)
get = getInt16be
-- Int32s are written as a 4 bytes in big endian format
instance Binary Int32 where
put = putInt32be
{-# INLINE putList #-}
putList xs =
put (length xs)
<> putBuilder (Prim.primMapListFixed Prim.int32BE xs)
get = getInt32be
-- Int64s are written as a 8 bytes in big endian format
instance Binary Int64 where
put = putInt64be
{-# INLINE putList #-}
putList xs =
put (length xs)
<> putBuilder (Prim.primMapListFixed Prim.int64BE xs)
get = getInt64be
------------------------------------------------------------------------
-- Words are are written as Word64s, that is, 8 bytes in big endian format
instance Binary Word where
put = putWord64be . fromIntegral
{-# INLINE putList #-}
putList xs =
put (length xs)
<> putBuilder (Prim.primMapListFixed Prim.word64BE (map fromIntegral xs))
get = liftM fromIntegral getWord64be
-- Ints are are written as Int64s, that is, 8 bytes in big endian format
instance Binary Int where
put = putInt64be . fromIntegral
{-# INLINE putList #-}
putList xs =
put (length xs)
<> putBuilder (Prim.primMapListFixed Prim.int64BE (map fromIntegral xs))
get = liftM fromIntegral getInt64be
------------------------------------------------------------------------
--
-- Portable, and pretty efficient, serialisation of Integer
--
-- Fixed-size type for a subset of Integer
type SmallInt = Int32
-- Integers are encoded in two ways: if they fit inside a SmallInt,
-- they're written as a byte tag, and that value. If the Integer value
-- is too large to fit in a SmallInt, it is written as a byte array,
-- along with a sign and length field.
instance Binary Integer where
{-# INLINE put #-}
put n | n >= lo && n <= hi =
putBuilder (Prim.primFixed (Prim.word8 Prim.>*< Prim.int32BE) (0, fromIntegral n))
where
lo = fromIntegral (minBound :: SmallInt) :: Integer
hi = fromIntegral (maxBound :: SmallInt) :: Integer
put n =
putWord8 1
<> put sign
<> put (unroll (abs n)) -- unroll the bytes
where
sign = fromIntegral (signum n) :: Word8
{-# INLINE get #-}
get = do
tag <- get :: Get Word8
case tag of
0 -> liftM fromIntegral (get :: Get SmallInt)
_ -> do sign <- get
bytes <- get
let v = roll bytes
return $! if sign == (1 :: Word8) then v else - v
-- | /Since: 0.8.0.0/
#ifdef HAS_FIXED_CONSTRUCTOR
instance Binary (Fixed.Fixed a) where
put (Fixed.MkFixed a) = put a
get = Fixed.MkFixed `liftM` get
#else
instance forall a. Fixed.HasResolution a => Binary (Fixed.Fixed a) where
-- Using undefined :: Maybe a as a proxy, as Data.Proxy is introduced only in base-4.7
put x = put (truncate (x * fromInteger (Fixed.resolution (undefined :: Maybe a))) :: Integer)
get = (\x -> fromInteger x / fromInteger (Fixed.resolution (undefined :: Maybe a))) `liftM` get
#endif
--
-- Fold and unfold an Integer to and from a list of its bytes
--
unroll :: (Integral a, Bits a) => a -> [Word8]
unroll = unfoldr step
where
step 0 = Nothing
step i = Just (fromIntegral i, i `shiftR` 8)
roll :: (Integral a, Bits a) => [Word8] -> a
roll = foldl' unstep 0 . reverse
where
unstep a b = a `shiftL` 8 .|. fromIntegral b
#ifdef HAS_NATURAL
-- Fixed-size type for a subset of Natural
type NaturalWord = Word64
-- | /Since: 0.7.3.0/
instance Binary Natural where
{-# INLINE put #-}
put n | n <= hi =
putWord8 0
<> put (fromIntegral n :: NaturalWord) -- fast path
where
hi = fromIntegral (maxBound :: NaturalWord) :: Natural
put n =
putWord8 1
<> put (unroll (abs n)) -- unroll the bytes
{-# INLINE get #-}
get = do
tag <- get :: Get Word8
case tag of
0 -> liftM fromIntegral (get :: Get NaturalWord)
_ -> do bytes <- get
return $! roll bytes
#endif
{-
--
-- An efficient, raw serialisation for Integer (GHC only)
--
-- TODO This instance is not architecture portable. GMP stores numbers as
-- arrays of machine sized words, so the byte format is not portable across
-- architectures with different endianness and word size.
import Data.ByteString.Base (toForeignPtr,unsafePackAddress, memcpy)
import GHC.Base hiding (ord, chr)
import GHC.Prim
import GHC.Ptr (Ptr(..))
import GHC.IOBase (IO(..))
instance Binary Integer where
put (S# i) = putWord8 0 >> put (I# i)
put (J# s ba) = do
putWord8 1
put (I# s)
put (BA ba)
get = do
b <- getWord8
case b of
0 -> do (I# i#) <- get
return (S# i#)
_ -> do (I# s#) <- get
(BA a#) <- get
return (J# s# a#)
instance Binary ByteArray where
-- Pretty safe.
put (BA ba) =
let sz = sizeofByteArray# ba -- (primitive) in *bytes*
addr = byteArrayContents# ba
bs = unsafePackAddress (I# sz) addr
in put bs -- write as a ByteString. easy, yay!
-- Pretty scary. Should be quick though
get = do
(fp, off, n@(I# sz)) <- liftM toForeignPtr get -- so decode a ByteString
assert (off == 0) $ return $ unsafePerformIO $ do
(MBA arr) <- newByteArray sz -- and copy it into a ByteArray#
let to = byteArrayContents# (unsafeCoerce# arr) -- urk, is this safe?
withForeignPtr fp $ \from -> memcpy (Ptr to) from (fromIntegral n)
freezeByteArray arr
-- wrapper for ByteArray#
data ByteArray = BA {-# UNPACK #-} !ByteArray#
data MBA = MBA {-# UNPACK #-} !(MutableByteArray# RealWorld)
newByteArray :: Int# -> IO MBA
newByteArray sz = IO $ \s ->
case newPinnedByteArray# sz s of { (# s', arr #) ->
(# s', MBA arr #) }
freezeByteArray :: MutableByteArray# RealWorld -> IO ByteArray
freezeByteArray arr = IO $ \s ->
case unsafeFreezeByteArray# arr s of { (# s', arr' #) ->
(# s', BA arr' #) }
-}
instance (Binary a,Integral a) => Binary (R.Ratio a) where
put r = put (R.numerator r) <> put (R.denominator r)
get = liftM2 (R.%) get get
instance Binary a => Binary (Complex a) where
{-# INLINE put #-}
put (r :+ i) = put (r, i)
{-# INLINE get #-}
get = (\(r,i) -> r :+ i) <$> get
------------------------------------------------------------------------
-- Char is serialised as UTF-8
instance Binary Char where
put = putCharUtf8
putList str = put (length str) <> putStringUtf8 str
get = do
let getByte = liftM (fromIntegral :: Word8 -> Int) get
shiftL6 = flip shiftL 6 :: Int -> Int
w <- getByte
r <- case () of
_ | w < 0x80 -> return w
| w < 0xe0 -> do
x <- liftM (xor 0x80) getByte
return (x .|. shiftL6 (xor 0xc0 w))
| w < 0xf0 -> do
x <- liftM (xor 0x80) getByte
y <- liftM (xor 0x80) getByte
return (y .|. shiftL6 (x .|. shiftL6
(xor 0xe0 w)))
| otherwise -> do
x <- liftM (xor 0x80) getByte
y <- liftM (xor 0x80) getByte
z <- liftM (xor 0x80) getByte
return (z .|. shiftL6 (y .|. shiftL6
(x .|. shiftL6 (xor 0xf0 w))))
getChr r
where
getChr w
| w <= 0x10ffff = return $! toEnum $ fromEnum w
| otherwise = fail "Not a valid Unicode code point!"
------------------------------------------------------------------------
-- Instances for the first few tuples
instance (Binary a, Binary b) => Binary (a,b) where
put (a,b) = put a <> put b
get = liftM2 (,) get get
instance (Binary a, Binary b, Binary c) => Binary (a,b,c) where
put (a,b,c) = put a <> put b <> put c
get = liftM3 (,,) get get get
instance (Binary a, Binary b, Binary c, Binary d) => Binary (a,b,c,d) where
put (a,b,c,d) = put a <> put b <> put c <> put d
get = liftM4 (,,,) get get get get
instance (Binary a, Binary b, Binary c, Binary d, Binary e) => Binary (a,b,c,d,e) where
put (a,b,c,d,e) = put a <> put b <> put c <> put d <> put e
get = liftM5 (,,,,) get get get get get
--
-- and now just recurse:
--
instance (Binary a, Binary b, Binary c, Binary d, Binary e, Binary f)
=> Binary (a,b,c,d,e,f) where
put (a,b,c,d,e,f) = put (a,(b,c,d,e,f))
get = do (a,(b,c,d,e,f)) <- get ; return (a,b,c,d,e,f)
instance (Binary a, Binary b, Binary c, Binary d, Binary e, Binary f, Binary g)
=> Binary (a,b,c,d,e,f,g) where
put (a,b,c,d,e,f,g) = put (a,(b,c,d,e,f,g))
get = do (a,(b,c,d,e,f,g)) <- get ; return (a,b,c,d,e,f,g)
instance (Binary a, Binary b, Binary c, Binary d, Binary e,
Binary f, Binary g, Binary h)
=> Binary (a,b,c,d,e,f,g,h) where
put (a,b,c,d,e,f,g,h) = put (a,(b,c,d,e,f,g,h))
get = do (a,(b,c,d,e,f,g,h)) <- get ; return (a,b,c,d,e,f,g,h)
instance (Binary a, Binary b, Binary c, Binary d, Binary e,
Binary f, Binary g, Binary h, Binary i)
=> Binary (a,b,c,d,e,f,g,h,i) where
put (a,b,c,d,e,f,g,h,i) = put (a,(b,c,d,e,f,g,h,i))
get = do (a,(b,c,d,e,f,g,h,i)) <- get ; return (a,b,c,d,e,f,g,h,i)
instance (Binary a, Binary b, Binary c, Binary d, Binary e,
Binary f, Binary g, Binary h, Binary i, Binary j)
=> Binary (a,b,c,d,e,f,g,h,i,j) where
put (a,b,c,d,e,f,g,h,i,j) = put (a,(b,c,d,e,f,g,h,i,j))
get = do (a,(b,c,d,e,f,g,h,i,j)) <- get ; return (a,b,c,d,e,f,g,h,i,j)
------------------------------------------------------------------------
-- Container types
instance Binary a => Binary [a] where
put = putList
get = do n <- get :: Get Int
getMany n
-- | 'getMany n' get 'n' elements in order, without blowing the stack.
getMany :: Binary a => Int -> Get [a]
getMany n = go [] n
where
go xs 0 = return $! reverse xs
go xs i = do x <- get
-- we must seq x to avoid stack overflows due to laziness in
-- (>>=)
x `seq` go (x:xs) (i-1)
{-# INLINE getMany #-}
instance (Binary a) => Binary (Maybe a) where
put Nothing = putWord8 0
put (Just x) = putWord8 1 <> put x
get = do
w <- getWord8
case w of
0 -> return Nothing
_ -> liftM Just get
instance (Binary a, Binary b) => Binary (Either a b) where
put (Left a) = putWord8 0 <> put a
put (Right b) = putWord8 1 <> put b
get = do
w <- getWord8
case w of
0 -> liftM Left get
_ -> liftM Right get
------------------------------------------------------------------------
-- ByteStrings (have specially efficient instances)
instance Binary B.ByteString where
put bs = put (B.length bs)
<> putByteString bs
get = get >>= getByteString
--
-- Using old versions of fps, this is a type synonym, and non portable
--
-- Requires 'flexible instances'
--
instance Binary ByteString where
put bs = put (fromIntegral (L.length bs) :: Int)
<> putLazyByteString bs
get = get >>= getLazyByteString
#if MIN_VERSION_bytestring(0,10,4)
instance Binary BS.ShortByteString where
put bs = put (BS.length bs)
<> putShortByteString bs
get = get >>= fmap BS.toShort . getByteString
#endif
------------------------------------------------------------------------
-- Maps and Sets
instance (Binary a) => Binary (Set.Set a) where
put s = put (Set.size s) <> mapM_ put (Set.toAscList s)
get = liftM Set.fromDistinctAscList get
instance (Binary k, Binary e) => Binary (Map.Map k e) where
put m = put (Map.size m) <> mapM_ put (Map.toAscList m)
get = liftM Map.fromDistinctAscList get
instance Binary IntSet.IntSet where
put s = put (IntSet.size s) <> mapM_ put (IntSet.toAscList s)
get = liftM IntSet.fromDistinctAscList get
instance (Binary e) => Binary (IntMap.IntMap e) where
put m = put (IntMap.size m) <> mapM_ put (IntMap.toAscList m)
get = liftM IntMap.fromDistinctAscList get
------------------------------------------------------------------------
-- Queues and Sequences
#if __GLASGOW_HASKELL__ >= 606
--
-- This is valid Hugs, but you need the most recent Hugs
--
instance (Binary e) => Binary (Seq.Seq e) where
put s = put (Seq.length s) <> Fold.mapM_ put s
get = do n <- get :: Get Int
rep Seq.empty n get
where rep xs 0 _ = return $! xs
rep xs n g = xs `seq` n `seq` do
x <- g
rep (xs Seq.|> x) (n-1) g
#endif
------------------------------------------------------------------------
-- Floating point
instance Binary Double where
put d = put (decodeFloat d)
get = do
x <- get
y <- get
return $! encodeFloat x y
instance Binary Float where
put f = put (decodeFloat f)
get = do
x <- get
y <- get
return $! encodeFloat x y
------------------------------------------------------------------------
-- Trees
instance (Binary e) => Binary (T.Tree e) where
put (T.Node r s) = put r <> put s
get = liftM2 T.Node get get
------------------------------------------------------------------------
-- Arrays
instance (Binary i, Ix i, Binary e) => Binary (Array i e) where
put a =
put (bounds a)
<> put (rangeSize $ bounds a) -- write the length
<> mapM_ put (elems a) -- now the elems.
get = do
bs <- get
n <- get -- read the length
xs <- getMany n -- now the elems.
return (listArray bs xs)
--
-- The IArray UArray e constraint is non portable. Requires flexible instances
--
instance (Binary i, Ix i, Binary e, IArray UArray e) => Binary (UArray i e) where
put a =
put (bounds a)
<> put (rangeSize $ bounds a) -- now write the length
<> mapM_ put (elems a)
get = do
bs <- get
n <- get
xs <- getMany n
return (listArray bs xs)
------------------------------------------------------------------------
-- Fingerprints
#ifdef HAS_GHC_FINGERPRINT
-- | /Since: 0.7.6.0/
instance Binary Fingerprint where
put (Fingerprint x1 x2) = put x1 <> put x2
get = do
x1 <- get
x2 <- get
return $! Fingerprint x1 x2
#endif
------------------------------------------------------------------------
-- Version
-- | /Since: 0.8.0.0/
instance Binary Version where
put (Version br tags) = put br <> put tags
get = Version <$> get <*> get