Binary: high performance, pure binary serialisation for Haskell ---------------------------------------------------------------------- The Binary Strike Team is pleased to announce the release of a new, pure, efficient binary serialisation library for Haskell, now available from Hackage: tarball: http://hackage.haskell.org/cgi-bin/hackage-scripts/package/binary/0.2 darcs: darcs get http://darcs.haskell.org/binary haddocks: http://www.cse.unsw.edu.au/~dons/binary/Data-Binary.html The 'binary' package provides efficient serialisation of Haskell values to and from lazy ByteStrings. ByteStrings constructed this way may then be written to disk, written to the network, or further processed (e.g. stored in memory directly, or compressed in memory with zlib or bzlib). Encoding and decoding are achieved by the functions: encode :: Binary a => a -> ByteString decode :: Binary a => ByteString -> a which mirror the read/show functions. Convenience functions for serialising to disk are also provided: encodeFile :: Binary a => FilePath -> a -> IO () decodeFile :: Binary a => FilePath -> IO a To serialise your Haskell data, all you need do is write an instance of Binary for your type. For example, suppose in an interpreter we had the data type: import Data.Binary import Control.Monad data Exp = IntE Int | OpE String Exp Exp We can serialise this to bytestring form with the following instance: instance Binary Exp where put (IntE i) = putWord8 0 >> put i put (OpE s e1 e2) = putWord8 1 >> put s >> put e1 >> put e2 get = do tag <- getWord8 case tag of 0 -> liftM IntE get 1 -> liftM3 OpE get get get The binary library has been heavily tuned for performance, particularly for writing speed. Throughput of up to 160M/s has been achieved in practice, and in general speed is on par or better than NewBinary, with the advantage of a pure interface. Efforts are underway to improve performance still further. Plans are also taking shape for a parser combinator library on top of binary, for bit parsing and foreign structure parsing (e.g. network protocols). Several projects are using binary already for serialisation: lambdabot : state file serialisation hmp3 : mp3 file database hpaste.org : pastes are stored in memory as compressed bytestrings, and serialised to disk on MACID checkpoints Binary was developed by a team of 8 during the Haskell Hackathon, Hac 07, and received 200+ commits over that period. You can see the commit graph here: http://www.cse.unsw.edu.au/~dons/images/commits/community/binary-commits.png The use of QuickCheck was critical to the rapid, safe development of the library. The API was developed in conjunction with the QuickCheck properties that checked the API for sanity. We were thus able to improve performance while maintaining stability. We feel that QuickCheck should be an integral part of the development strategy for all new Haskell libraries. Don't write code without it! Binary is portable, using the foreign function interface and cpp, and is tested with Hugs and GHC. Happy hacking! The Binary Strike Team, Lennart Kolmodin Duncan Coutts Don Stewart Spencer Janssen David Himmelstrup Bjorn Bringert Ross Paterson Einar Karttunen