{-# LANGUAGE FlexibleInstances, FlexibleContexts #-}
-- | This is a layer on top of "Data.Binary" with its own 'Binary' class
-- and customised instances for 'Word', 'Int' and 'Double'.
-- The 'Int' and 'Word' instance use a variable-length encoding to save space
-- for small numbers. The 'Double' instance uses the standard IEEE754 encoding.
module PGF.Data.Binary (
-- * The Binary class
Binary(..)
-- * The Get and Put monads
, Get , Put, runPut
-- * Useful helpers for writing instances
, putWord8 , getWord8 , putWord16be , getWord16be
-- * Binary serialisation
, encode , decode
-- * IO functions for serialisation
, encodeFile , decodeFile
, encodeFile_ , decodeFile_
-- * Useful
, Word8, Word16
) where
import Data.Word
import qualified Data.Binary as Bin
import Data.Binary.Put
import Data.Binary.Get
import Data.Binary.IEEE754 ( putFloat64be, getFloat64be)
import Control.Monad
import Control.Exception
import Foreign
import System.IO
import Data.ByteString.Lazy (ByteString)
import qualified Data.ByteString.Lazy as L
--import Data.Char (chr,ord)
--import Data.List (unfoldr)
-- And needed for the instances:
import qualified Data.ByteString as B
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
------------------------------------------------------------------------
-- | 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 parsing 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
------------------------------------------------------------------------
-- Wrappers to run the underlying monad
-- | Encode a value using binary serialisation to a lazy ByteString.
--
encode :: Binary a => a -> ByteString
encode = runPut . put
{-# INLINE encode #-}
-- | Decode a value from a lazy ByteString, reconstructing the original structure.
--
decode :: Binary a => ByteString -> a
decode = runGet get
------------------------------------------------------------------------
-- Convenience IO operations
-- | Lazily serialise a value to a file
--
-- This is just a convenience function, it's defined simply as:
--
-- > encodeFile f = B.writeFile f . encode
--
-- So for example if you wanted to compress as well, you could use:
--
-- > B.writeFile f . compress . encode
--
encodeFile :: Binary a => FilePath -> a -> IO ()
encodeFile f v = L.writeFile f (encode v)
encodeFile_ :: FilePath -> Put -> IO ()
encodeFile_ f m = L.writeFile f (runPut m)
-- | Lazily reconstruct a value previously written to a file.
--
-- This is just a convenience function, it's defined simply as:
--
-- > decodeFile f = return . decode =<< B.readFile f
--
-- So for example if you wanted to decompress as well, you could use:
--
-- > return . decode . decompress =<< B.readFile f
--
decodeFile :: Binary a => FilePath -> IO a
decodeFile f = bracket (openBinaryFile f ReadMode) hClose $ \h -> do
s <- L.hGetContents h
evaluate $ runGet get s
decodeFile_ :: FilePath -> Get a -> IO a
decodeFile_ f m = bracket (openBinaryFile f ReadMode) hClose $ \h -> do
s <- L.hGetContents h
evaluate $ runGet m s
------------------------------------------------------------------------
-- For ground types, the standard instances can be reused,
-- but for container types it would imply using
-- the standard instances for all types of values in the container...
instance Binary () where put=Bin.put; get=Bin.get
instance Binary Bool where put=Bin.put; get=Bin.get
instance Binary Word8 where put=Bin.put; get=Bin.get
instance Binary Word16 where put=Bin.put; get=Bin.get
instance Binary Char where put=Bin.put; get=Bin.get
-- -- GF doesn't need these:
--instance Binary Ordering where put=Bin.put; get=Bin.get
--instance Binary Word32 where put=Bin.put; get=Bin.get
--instance Binary Word64 where put=Bin.put; get=Bin.get
--instance Binary Int8 where put=Bin.put; get=Bin.get
--instance Binary Int16 where put=Bin.put; get=Bin.get
--instance Binary Int32 where put=Bin.put; get=Bin.get
--instance Binary Int64 where put=Bin.put; get=Bin.get -- needed by instance Binary ByteString
------------------------------------------------------------------------
-- Words are written as sequence of bytes. The last bit of each
-- byte indicates whether there are more bytes to be read
instance Binary Word where
put i | i <= 0x7f = do put a
| i <= 0x3fff = do put (a .|. 0x80)
put b
| i <= 0x1fffff = do put (a .|. 0x80)
put (b .|. 0x80)
put c
| i <= 0xfffffff = do put (a .|. 0x80)
put (b .|. 0x80)
put (c .|. 0x80)
put d
-- -- #if WORD_SIZE_IN_BITS < 64
| otherwise = do put (a .|. 0x80)
put (b .|. 0x80)
put (c .|. 0x80)
put (d .|. 0x80)
put e
{-
-- Restricted to 32 bits even on 64-bit systems, so that negative
-- Ints are written as 5 bytes instead of 10 bytes (TH 2013-02-13)
--#else
| i <= 0x7ffffffff = do put (a .|. 0x80)
put (b .|. 0x80)
put (c .|. 0x80)
put (d .|. 0x80)
put e
| i <= 0x3ffffffffff = do put (a .|. 0x80)
put (b .|. 0x80)
put (c .|. 0x80)
put (d .|. 0x80)
put (e .|. 0x80)
put f
| i <= 0x1ffffffffffff = do put (a .|. 0x80)
put (b .|. 0x80)
put (c .|. 0x80)
put (d .|. 0x80)
put (e .|. 0x80)
put (f .|. 0x80)
put g
| i <= 0xffffffffffffff = do put (a .|. 0x80)
put (b .|. 0x80)
put (c .|. 0x80)
put (d .|. 0x80)
put (e .|. 0x80)
put (f .|. 0x80)
put (g .|. 0x80)
put h
| i <= 0xffffffffffffff = do put (a .|. 0x80)
put (b .|. 0x80)
put (c .|. 0x80)
put (d .|. 0x80)
put (e .|. 0x80)
put (f .|. 0x80)
put (g .|. 0x80)
put h
| i <= 0x7fffffffffffffff = do put (a .|. 0x80)
put (b .|. 0x80)
put (c .|. 0x80)
put (d .|. 0x80)
put (e .|. 0x80)
put (f .|. 0x80)
put (g .|. 0x80)
put (h .|. 0x80)
put j
| otherwise = do put (a .|. 0x80)
put (b .|. 0x80)
put (c .|. 0x80)
put (d .|. 0x80)
put (e .|. 0x80)
put (f .|. 0x80)
put (g .|. 0x80)
put (h .|. 0x80)
put (j .|. 0x80)
put k
-- #endif
-}
where
a = fromIntegral ( i .&. 0x7f) :: Word8
b = fromIntegral (shiftR i 7 .&. 0x7f) :: Word8
c = fromIntegral (shiftR i 14 .&. 0x7f) :: Word8
d = fromIntegral (shiftR i 21 .&. 0x7f) :: Word8
e = fromIntegral (shiftR i 28 .&. 0x7f) :: Word8
{-
f = fromIntegral (shiftR i 35 .&. 0x7f) :: Word8
g = fromIntegral (shiftR i 42 .&. 0x7f) :: Word8
h = fromIntegral (shiftR i 49 .&. 0x7f) :: Word8
j = fromIntegral (shiftR i 56 .&. 0x7f) :: Word8
k = fromIntegral (shiftR i 63 .&. 0x7f) :: Word8
-}
get = do i <- getWord8
(if i <= 0x7f
then return (fromIntegral i)
else do n <- get
return $ (n `shiftL` 7) .|. (fromIntegral (i .&. 0x7f)))
-- Int has the same representation as Word
instance Binary Int where
put i = put (fromIntegral i :: Word)
get = liftM toInt32 (get :: Get Word)
where
-- restrict to 32 bits (for PGF portability, TH 2013-02-13)
toInt32 w = fromIntegral (fromIntegral w::Int32)::Int
------------------------------------------------------------------------
--
-- 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 = do
putWord8 0
put (fromIntegral n :: SmallInt) -- fast path
where
lo = fromIntegral (minBound :: SmallInt) :: Integer
hi = fromIntegral (maxBound :: SmallInt) :: Integer
put n = do
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
--
-- Fold and unfold an Integer to and from a list of its bytes
--
unroll :: Integer -> [Word8]
unroll = unfoldr step
where
step 0 = Nothing
step i = Just (fromIntegral i, i `shiftR` 8)
roll :: [Word8] -> Integer
roll = foldr unstep 0
where
unstep b a = a `shiftL` 8 .|. fromIntegral b
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
-}
------------------------------------------------------------------------
-- 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 l = put (length l) >> mapM_ put l
get = do n <- get :: Get Int
xs <- replicateM n get
return xs
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 = do 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 = do put (fromIntegral (L.length bs) :: Int)
putLazyByteString bs
get = get >>= getLazyByteString
-}
------------------------------------------------------------------------
-- Maps and Sets
instance (Ord a, Binary a) => Binary (Set.Set a) where
put s = put (Set.size s) >> mapM_ put (Set.toAscList s)
get = liftM Set.fromDistinctAscList get
instance (Ord k, 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
------------------------------------------------------------------------
-- Floating point
-- instance Binary Double where
-- put d = put (decodeFloat d)
-- get = liftM2 encodeFloat get get
instance Binary Double where
put = putFloat64be
get = getFloat64be
{-
instance Binary Float where
put f = put (decodeFloat f)
get = liftM2 encodeFloat get get
-}
------------------------------------------------------------------------
-- 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 = do
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 <- replicateM n get -- 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 = do
put (bounds a)
put (rangeSize $ bounds a) -- now write the length
mapM_ put (elems a)
get = do
bs <- get
n <- get
xs <- replicateM n get
return (listArray bs xs)