Data/ByteString/Builder/Prim/Binary.hs

    {-# LANGUAGE CPP, BangPatterns #-}
    #if __GLASGOW_HASKELL__ >= 701
    {-# LANGUAGE Trustworthy #-}
    #endif
    -- | Copyright   : (c) 2010-2011 Simon Meier
    -- License       : BSD3-style (see LICENSE)
    --
    -- Maintainer    : Simon Meier <iridcode@gmail.com>
    -- Portability   : GHC
    --
    module Data.ByteString.Builder.Prim.Binary (

      -- ** Binary encodings
        int8
      , word8

      -- *** Big-endian
      , int16BE
      , int32BE
      , int64BE

      , word16BE
      , word32BE
      , word64BE

      , floatBE
      , doubleBE

      -- *** Little-endian
      , int16LE
      , int32LE
      , int64LE

      , word16LE
      , word32LE
      , word64LE

      , floatLE
      , doubleLE

      -- *** Non-portable, host-dependent
      , intHost
      , int16Host
      , int32Host
      , int64Host

      , wordHost
      , word16Host
      , word32Host
      , word64Host

      , floatHost
      , doubleHost

      ) where

    import Data.ByteString.Builder.Prim.Internal
    import Data.ByteString.Builder.Prim.Internal.UncheckedShifts
    import Data.ByteString.Builder.Prim.Internal.Floating

    import Foreign

    #include "MachDeps.h"

    ------------------------------------------------------------------------------
    -- Binary encoding
    ------------------------------------------------------------------------------

    -- Word encodings
    -----------------

    -- | Encoding single unsigned bytes as-is.
    --
    {-# INLINE word8 #-}
    word8 :: FixedPrim Word8
    word8 = storableToF

    --
    -- We rely on the fromIntegral to do the right masking for us.
    -- The inlining here is critical, and can be worth 4x performance
    --

    -- | Encoding 'Word16's in big endian format.
    {-# INLINE word16BE #-}
    word16BE :: FixedPrim Word16
    #ifdef WORDS_BIGENDIAN
    word16BE = word16Host
    #else
    word16BE = fixedPrim 2 $ \w p -> do
        poke p               (fromIntegral (shiftr_w16 w 8) :: Word8)
        poke (p `plusPtr` 1) (fromIntegral (w)              :: Word8)
    #endif

    -- | Encoding 'Word16's in little endian format.
    {-# INLINE word16LE #-}
    word16LE :: FixedPrim Word16
    #ifdef WORDS_BIGENDIAN
    word16LE = fixedPrim 2 $ \w p -> do
        poke p               (fromIntegral (w)              :: Word8)
        poke (p `plusPtr` 1) (fromIntegral (shiftr_w16 w 8) :: Word8)
    #else
    word16LE = word16Host
    #endif

    -- | Encoding 'Word32's in big endian format.
    {-# INLINE word32BE #-}
    word32BE :: FixedPrim Word32
    #ifdef WORDS_BIGENDIAN
    word32BE = word32Host
    #else
    word32BE = fixedPrim 4 $ \w p -> do
        poke p               (fromIntegral (shiftr_w32 w 24) :: Word8)
        poke (p `plusPtr` 1) (fromIntegral (shiftr_w32 w 16) :: Word8)
        poke (p `plusPtr` 2) (fromIntegral (shiftr_w32 w  8) :: Word8)
        poke (p `plusPtr` 3) (fromIntegral (w)               :: Word8)
    #endif

    -- | Encoding 'Word32's in little endian format.
    {-# INLINE word32LE #-}
    word32LE :: FixedPrim Word32
    #ifdef WORDS_BIGENDIAN
    word32LE = fixedPrim 4 $ \w p -> do
        poke p               (fromIntegral (w)               :: Word8)
        poke (p `plusPtr` 1) (fromIntegral (shiftr_w32 w  8) :: Word8)
        poke (p `plusPtr` 2) (fromIntegral (shiftr_w32 w 16) :: Word8)
        poke (p `plusPtr` 3) (fromIntegral (shiftr_w32 w 24) :: Word8)
    #else
    word32LE = word32Host
    #endif

    -- on a little endian machine:
    -- word32LE w32 = fixedPrim 4 (\w p -> poke (castPtr p) w32)

    -- | Encoding 'Word64's in big endian format.
    {-# INLINE word64BE #-}
    word64BE :: FixedPrim Word64
    #ifdef WORDS_BIGENDIAN
    word64BE = word64Host
    #else
    #if WORD_SIZE_IN_BITS < 64
    --
    -- To avoid expensive 64 bit shifts on 32 bit machines, we cast to
    -- Word32, and write that
    --
    word64BE =
        fixedPrim 8 $ \w p -> do
            let a = fromIntegral (shiftr_w64 w 32) :: Word32
                b = fromIntegral w                 :: Word32
            poke p               (fromIntegral (shiftr_w32 a 24) :: Word8)
            poke (p `plusPtr` 1) (fromIntegral (shiftr_w32 a 16) :: Word8)
            poke (p `plusPtr` 2) (fromIntegral (shiftr_w32 a  8) :: Word8)
            poke (p `plusPtr` 3) (fromIntegral (a)               :: Word8)
            poke (p `plusPtr` 4) (fromIntegral (shiftr_w32 b 24) :: Word8)
            poke (p `plusPtr` 5) (fromIntegral (shiftr_w32 b 16) :: Word8)
            poke (p `plusPtr` 6) (fromIntegral (shiftr_w32 b  8) :: Word8)
            poke (p `plusPtr` 7) (fromIntegral (b)               :: Word8)
    #else
    word64BE = fixedPrim 8 $ \w p -> do
        poke p               (fromIntegral (shiftr_w64 w 56) :: Word8)
        poke (p `plusPtr` 1) (fromIntegral (shiftr_w64 w 48) :: Word8)
        poke (p `plusPtr` 2) (fromIntegral (shiftr_w64 w 40) :: Word8)
        poke (p `plusPtr` 3) (fromIntegral (shiftr_w64 w 32) :: Word8)
        poke (p `plusPtr` 4) (fromIntegral (shiftr_w64 w 24) :: Word8)
        poke (p `plusPtr` 5) (fromIntegral (shiftr_w64 w 16) :: Word8)
        poke (p `plusPtr` 6) (fromIntegral (shiftr_w64 w  8) :: Word8)
        poke (p `plusPtr` 7) (fromIntegral (w)               :: Word8)
    #endif
    #endif

    -- | Encoding 'Word64's in little endian format.
    {-# INLINE word64LE #-}
    word64LE :: FixedPrim Word64
    #ifdef WORDS_BIGENDIAN
    #if WORD_SIZE_IN_BITS < 64
    word64LE =
        fixedPrim 8 $ \w p -> do
            let b = fromIntegral (shiftr_w64 w 32) :: Word32
                a = fromIntegral w                 :: Word32
            poke (p)             (fromIntegral (a)               :: Word8)
            poke (p `plusPtr` 1) (fromIntegral (shiftr_w32 a  8) :: Word8)
            poke (p `plusPtr` 2) (fromIntegral (shiftr_w32 a 16) :: Word8)
            poke (p `plusPtr` 3) (fromIntegral (shiftr_w32 a 24) :: Word8)
            poke (p `plusPtr` 4) (fromIntegral (b)               :: Word8)
            poke (p `plusPtr` 5) (fromIntegral (shiftr_w32 b  8) :: Word8)
            poke (p `plusPtr` 6) (fromIntegral (shiftr_w32 b 16) :: Word8)
            poke (p `plusPtr` 7) (fromIntegral (shiftr_w32 b 24) :: Word8)
    #else
    word64LE = fixedPrim 8 $ \w p -> do
        poke p               (fromIntegral (w)               :: Word8)
        poke (p `plusPtr` 1) (fromIntegral (shiftr_w64 w  8) :: Word8)
        poke (p `plusPtr` 2) (fromIntegral (shiftr_w64 w 16) :: Word8)
        poke (p `plusPtr` 3) (fromIntegral (shiftr_w64 w 24) :: Word8)
        poke (p `plusPtr` 4) (fromIntegral (shiftr_w64 w 32) :: Word8)
        poke (p `plusPtr` 5) (fromIntegral (shiftr_w64 w 40) :: Word8)
        poke (p `plusPtr` 6) (fromIntegral (shiftr_w64 w 48) :: Word8)
        poke (p `plusPtr` 7) (fromIntegral (shiftr_w64 w 56) :: Word8)
    #endif
    #else
    word64LE = word64Host
    #endif

    -- | Encode a single native machine 'Word'. The 'Word's is encoded in host order,
    -- host endian form, for the machine you are on. On a 64 bit machine the 'Word'
    -- is an 8 byte value, on a 32 bit machine, 4 bytes. Values encoded this way
    -- are not portable to different endian or word sized machines, without
    -- conversion.
    --
    {-# INLINE wordHost #-}
    wordHost :: FixedPrim Word
    wordHost = storableToF

    -- | Encoding 'Word16's in native host order and host endianness.
    {-# INLINE word16Host #-}
    word16Host :: FixedPrim Word16
    word16Host = storableToF

    -- | Encoding 'Word32's in native host order and host endianness.
    {-# INLINE word32Host #-}
    word32Host :: FixedPrim Word32
    word32Host = storableToF

    -- | Encoding 'Word64's in native host order and host endianness.
    {-# INLINE word64Host #-}
    word64Host :: FixedPrim Word64
    word64Host = storableToF

    ------------------------------------------------------------------------------
    -- Int encodings
    ------------------------------------------------------------------------------
    --
    -- We rely on 'fromIntegral' to do a loss-less conversion to the corresponding
    -- 'Word' type
    --
    ------------------------------------------------------------------------------

    -- | Encoding single signed bytes as-is.
    --
    {-# INLINE int8 #-}
    int8 :: FixedPrim Int8
    int8 = fromIntegral >$< word8

    -- | Encoding 'Int16's in big endian format.
    {-# INLINE int16BE #-}
    int16BE :: FixedPrim Int16
    int16BE = fromIntegral >$< word16BE

    -- | Encoding 'Int16's in little endian format.
    {-# INLINE int16LE #-}
    int16LE :: FixedPrim Int16
    int16LE = fromIntegral >$< word16LE

    -- | Encoding 'Int32's in big endian format.
    {-# INLINE int32BE #-}
    int32BE :: FixedPrim Int32
    int32BE = fromIntegral >$< word32BE

    -- | Encoding 'Int32's in little endian format.
    {-# INLINE int32LE #-}
    int32LE :: FixedPrim Int32
    int32LE = fromIntegral >$< word32LE

    -- | Encoding 'Int64's in big endian format.
    {-# INLINE int64BE #-}
    int64BE :: FixedPrim Int64
    int64BE = fromIntegral >$< word64BE

    -- | Encoding 'Int64's in little endian format.
    {-# INLINE int64LE #-}
    int64LE :: FixedPrim Int64
    int64LE = fromIntegral >$< word64LE

    -- TODO: Ensure that they are safe on architectures where an unaligned write is
    -- an error.

    -- | Encode a single native machine 'Int'. The 'Int's is encoded in host order,
    -- host endian form, for the machine you are on. On a 64 bit machine the 'Int'
    -- is an 8 byte value, on a 32 bit machine, 4 bytes. Values encoded this way
    -- are not portable to different endian or integer sized machines, without
    -- conversion.
    --
    {-# INLINE intHost #-}
    intHost :: FixedPrim Int
    intHost = storableToF

    -- | Encoding 'Int16's in native host order and host endianness.
    {-# INLINE int16Host #-}
    int16Host :: FixedPrim Int16
    int16Host = storableToF

    -- | Encoding 'Int32's in native host order and host endianness.
    {-# INLINE int32Host #-}
    int32Host :: FixedPrim Int32
    int32Host = storableToF

    -- | Encoding 'Int64's in native host order and host endianness.
    {-# INLINE int64Host #-}
    int64Host :: FixedPrim Int64
    int64Host = storableToF

    -- IEEE Floating Point Numbers
    ------------------------------

    -- | Encode a 'Float' in big endian format.
    {-# INLINE floatBE #-}
    floatBE :: FixedPrim Float
    floatBE = encodeFloatViaWord32F word32BE

    -- | Encode a 'Float' in little endian format.
    {-# INLINE floatLE #-}
    floatLE :: FixedPrim Float
    floatLE = encodeFloatViaWord32F word32LE

    -- | Encode a 'Double' in big endian format.
    {-# INLINE doubleBE #-}
    doubleBE :: FixedPrim Double
    doubleBE = encodeDoubleViaWord64F word64BE

    -- | Encode a 'Double' in little endian format.
    {-# INLINE doubleLE #-}
    doubleLE :: FixedPrim Double
    doubleLE = encodeDoubleViaWord64F word64LE

    -- | Encode a 'Float' in native host order and host endianness. Values written
    -- this way are not portable to different endian machines, without conversion.
    --
    {-# INLINE floatHost #-}
    floatHost :: FixedPrim Float
    floatHost = storableToF

    -- | Encode a 'Double' in native host order and host endianness.
    {-# INLINE doubleHost #-}
    doubleHost :: FixedPrim Double
    doubleHost = storableToF