{-# LANGUAGE CPP #-}-- |-- Copyright : (c) 2011 Simon Meier-- License : BSD3-style (see LICENSE)---- Maintainer : Simon Meier <iridcode@gmail.com>-- Stability : experimental-- Portability : GHC---- Hexadecimal encoding of nibbles (4-bit) and octets (8-bit) as ASCII-- characters.---- The current implementation is based on a table based encoding inspired by-- the code in the 'base64-bytestring' library by Bryan O'Sullivan. In our-- benchmarks on a 32-bit machine it turned out to be the fastest-- implementation option.--moduleData.ByteString.Builder.Prim.Internal.Base16(EncodingTable ,lowerTable ,encode8_as_16h )whereimportForeignimportGHC.Exts(Addr#,Ptr(..))
#if PURE_HASKELL
importqualifiedData.ByteString.Internal.PureasPure
#else
importForeign.C.Types
#endif
-- Creating the encoding table-------------------------------- | An encoding table for Base16 encoding.dataEncodingTable =EncodingTable Addr#-- | The encoding table for hexadecimal values with lower-case characters;-- e.g., deadbeef.lowerTable ::EncodingTable lowerTable :: EncodingTable
lowerTable =
#if PURE_HASKELL
casePure.lower_hex_tableofPtrp#->EncodingTablep#
#else
casePtr CChar
c_lower_hex_table ofPtrAddr#
p# ->Addr# -> EncodingTable
EncodingTable Addr#
p# foreignimportccall"&hs_bytestring_lower_hex_table"c_lower_hex_table ::PtrCChar
#endif
-- | Encode an octet as 16bit word comprising both encoded nibbles ordered-- according to the host endianness. Writing these 16bit to memory will write-- the nibbles in the correct order (i.e. big-endian).{-# INLINEencode8_as_16h #-}encode8_as_16h ::EncodingTable ->Word8->IOWord16encode8_as_16h :: EncodingTable -> Word8 -> IO Word16
encode8_as_16h (EncodingTable Addr#
table )=Ptr Word16 -> Int -> IO Word16
forall a. Storable a => Ptr a -> Int -> IO a
peekElemOff(Addr# -> Ptr Word16
forall a. Addr# -> Ptr a
PtrAddr#
table )(Int -> IO Word16) -> (Word8 -> Int) -> Word8 -> IO Word16
forall b c a. (b -> c) -> (a -> b) -> a -> c
.Word8 -> Int
forall a b. (Integral a, Num b) => a -> b
fromIntegral