quicklz 1.5.0.4 → 1.5.0.5

raw patch · 5 files changed

+42/−6 lines, 5 filesPVP: minor bump suggested

API additions: PVP suggests at least a minor version bump

API changes (from Hackage documentation)

Files

• Codec/Compression/QuickLZ.hsc +16/−1
• README +0/−3
• README.md +19/−0
• quicklz.cabal +2/−2
• tests/Properties.hs +5/−0

@@ -1,5 +1,4 @@ {-# LANGUAGE CPP, ForeignFunctionInterface #-}
-
 -- |
 -- Module      : Codec.Compression.QuickLZ
 -- Copyright   : (c) Austin Seipp 2011
@@ -40,6 +39,7 @@ ( -- * Compressing and decompressing strict 'ByteString's
   compress      -- :: S.ByteString -> S.ByteString
 , decompress    -- :: S.ByteString -> S.ByteString
+, decompress'   -- :: S.ByteString -> S.ByteString
 ) where
 
 import Foreign
@@ -80,6 +80,21 @@             c_ <- c_qlz_decompress cstr output decompress_state
             return $ c_ - 4 -- hack: remove 4 ending bytes off of output string
 {-# INLINEABLE decompress #-}
+
+-- | Decompress the input 'ByteString' and save memory via overlapping decompression.
+decompress' :: S.ByteString -> S.ByteString
+decompress' xs
+  | S.null xs = S.empty
+  | otherwise = 
+      unsafePerformIO . allocaBytes qlz_state_decompress_sz $ \decompress_state -> do
+        d <- U.unsafeUseAsCString xs c_qlz_size_decompressed
+        let sz = (d + (d `shiftR` 3) + 400)
+        SI.createAndTrim sz $ \output -> do
+          U.unsafeUseAsCStringLen xs $ \(cstr,clen) -> do
+            let dest = output `plusPtr` (sz - clen)
+            SI.memcpy dest (castPtr cstr) (fromIntegral clen)
+            c_ <- c_qlz_decompress dest output decompress_state
+            return $ c_ - 4 -- hack: remove 4 ending bytes off of output string
 
 -- 
 -- Simple bindings to some constants

@@ -1,3 +0,0 @@-hs-quicklz: haskell bindings to quicklz
-
-TODO

@@ -0,0 +1,19 @@+# hs-quicklz: haskell bindings to quicklz
+
+This library implements haskell bindings to [QuickLZ](http://quicklz.com), a fast
+compression library. The interface is very simple:
+
+    compress    :: ByteString -> ByteString
+    decompress  :: ByteString -> ByteString
+    decompress' :: ByteString -> ByteString -- overlapping decompression
+
+As the name states, QuickLZ is fast - very fast at both compression and decompression.
+Per its own benchmarks, at compression level 1, QuickLZ 1.5.0 has a compression speed
+of 308Mbyte/s, and a decompression speed of 358Mbyte/s (their benchmarks, Core i7 920.)
+This package has some benchmarks and tests associated - I would like to expand the benchmarks
+to include bigger data sets in the future.
+
+There is currently only an interface for strict bytestrings.
+
+I would like to implement the streaming mode functionality sometime in the future, perhaps
+tying it to John Millikin's [enumerator](http://hackage.haskell.org/package/enumerator) package.

@@ -1,5 +1,5 @@ name:                quicklz
-version:             1.5.0.4
+version:             1.5.0.5
 synopsis:            binding to QuickLZ compression library
 description:         
   This package provides a high level binding to the QuickLZ (<http://quicklz.com>) library
@@ -25,7 +25,7 @@ extra-source-files:
   cbits/quicklz.h, cbits/quicklz.c,
   tests/ex1.hs, tests/Properties.hs,
-  README
+  README.md
 
 source-repository head
   type: git

@@ -12,6 +12,7 @@                        testProperty "compression identity" prop_compression_id
                      , testProperty "decompress is pure" prop_decompress_pure
                      , testProperty "compress is pure" prop_compress_pure
+                     , testProperty "overlapping is correct" prop_overlap_id
                      ]
                    ]
 
@@ -24,3 +25,7 @@ 
 prop_compress_pure (S.pack -> xs) =
   (compress xs) == (compress xs)
+
+prop_overlap_id (S.pack -> xs) =
+  let z = compress xs
+  in (decompress z) == (decompress' z)