I need to deflate buffers that were compressed with zlib's compress and sent to me over the network. I don't think files help me there :-). On Oct 18, 2005, at 3:49 PM, Henning Thielemann wrote:

Darcs works with gzipped files.

-- http://wagerlabs.com/

Well, I just coded this. Feedback is welcome! One thing that I found interesting is that I actually have to allocate 4 bytes to pass the long into compress/uncompress. I thought that I could somehow obtain the address of the Haskell variable but this does not seem to be possible. Thanks, Joel -- {-# INCLUDE #-} {-# OPTIONS -fffi -fglasgow-exts #-} module ZLib ( compress, uncompress ) where import Foreign import Foreign.C import Data.FastPackedString import Prelude hiding (length) compress :: FastString -> IO FastString compress src = do let src_size :: CULong = fromIntegral $ length src dest_size :: CULong = compressBound src_size allocaBytes (sizeOf dest_size) $ \dest_size' -> unsafeUseAsCString src $ \src' -> do poke dest_size' dest_size generate (fromIntegral dest_size) $ \dest -> do err <- compress_ dest dest_size' (castPtr src') src_size dest_size <- peek dest_size' return $ fromIntegral dest_size uncompress :: FastString -> Int -> IO FastString uncompress src orig_size = do let src_size :: CULong = fromIntegral $ length src dest_size :: CULong = fromIntegral orig_size allocaBytes (sizeOf dest_size) $ \dest_size' -> unsafeUseAsCString src $ \src' -> do poke dest_size' dest_size generate (fromIntegral dest_size) $ \dest -> do err <- uncompress_ dest dest_size' (castPtr src') src_size dest_size <- peek dest_size' return $ fromIntegral dest_size foreign import ccall unsafe "compressBound" compressBound :: CULong -> CULong foreign import ccall unsafe "compress" compress_ :: Ptr Word8 -> Ptr CULong -> Ptr Word8 -> CULong -> IO CInt foreign import ccall unsafe "uncompress" uncompress_ :: Ptr Word8 -> Ptr CULong -> Ptr Word8 -> CULong -> IO CInt -- http://wagerlabs.com/

Hello John, Thursday, October 20, 2005, 4:12:36 AM, you wrote: JM> FastString seems to be a misnomer for this library. JM> what it provides is a fast _byte array_ with a lot of useful JM> operations, but it does not provide strings since it does not enforce JM> character encodings in the type system, which would be vital for a real JM> FastString library. In any case, just had to get that off my chest :) may be it can be named ByteArray? and then FastString.Latin1, FastString.UTF8... will use its utilities also, all UTF8 utilities may be placed outside of FastString.UTF8 module, because it can be used for something else btw, FastString is also a bit misnamed. it's really a CompactString. ghc's FastString was named so, imho, just because they provided hashes for fast string comparision -- Best regards, Bulat mailto:bulatz@HotPOP.com

Hello Donald, Thursday, October 20, 2005, 12:47:32 PM, you wrote:

...

JM> what it provides is a fast _byte array_ with a lot of useful

...

may be it can be named ByteArray? and then FastString.Latin1,

DBS> Well, it's a PackedString really, isn't it? of course :) btw, may be it can be extended by processing any memory arrays, not just ByteArray? smthg like data Vector a = PS !Int !(ForeignPtr a) -- Best regards, Bulat mailto:bulatz@HotPOP.com