79 lines
2.4 KiB
Haskell
79 lines
2.4 KiB
Haskell
-- |
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-- Module : Crypto.Internal.Hex
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-- License : BSD-style
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-- Maintainer : Vincent Hanquez <vincent@snarc.org>
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-- Stability : experimental
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-- Portability : unknown
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--
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-- Hexadecimal escaper
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--
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{-# LANGUAGE MagicHash #-}
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{-# LANGUAGE UnboxedTuples #-}
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{-# LANGUAGE OverloadedStrings #-}
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{-# LANGUAGE BangPatterns #-}
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module Crypto.Internal.Hex
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( showHexadecimal
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, toHexadecimal
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) where
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import Crypto.Internal.Compat
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import Data.Word
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import GHC.Prim
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import GHC.Types
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import GHC.Word
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import Foreign.Storable
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import Foreign.Ptr (Ptr)
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showHexadecimal :: Ptr Word8 -> Int -> String
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showHexadecimal ptr len = loop 0
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where
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loop i
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| i == len = []
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| otherwise =
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let !(W8# b) = byteIndex i
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(# w1, w2 #) = convertByte b
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in wToChar w1 : wToChar w2 : loop (i+1)
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wToChar :: Word# -> Char
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wToChar w = toEnum (I# (word2Int# w))
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byteIndex :: Int -> Word8
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byteIndex i = unsafeDoIO (peekByteOff ptr i)
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toHexadecimal :: Ptr Word8 -> Ptr Word8 -> Int -> IO ()
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toHexadecimal bout bin n = loop 0
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where loop i
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| i == n = return ()
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| otherwise = do
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(W8# w) <- peekByteOff bin i
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let (# w1, w2 #) = convertByte w
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pokeByteOff bout (i * 2) (W8# w1)
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pokeByteOff bout (i * 2 + 1) (W8# w2)
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loop (i+1)
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convertByte :: Word# -> (# Word#, Word# #)
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convertByte b = (# r tableHi b, r tableLo b #)
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where
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r :: Addr# -> Word# -> Word#
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r table index = indexWord8OffAddr# table (word2Int# index)
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!tableLo =
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"0123456789abcdef0123456789abcdef\
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\0123456789abcdef0123456789abcdef\
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\0123456789abcdef0123456789abcdef\
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\0123456789abcdef0123456789abcdef\
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\0123456789abcdef0123456789abcdef\
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\0123456789abcdef0123456789abcdef\
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\0123456789abcdef0123456789abcdef\
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\0123456789abcdef0123456789abcdef"#
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!tableHi =
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"00000000000000001111111111111111\
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\22222222222222223333333333333333\
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\44444444444444445555555555555555\
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\66666666666666667777777777777777\
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\88888888888888889999999999999999\
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\aaaaaaaaaaaaaaaabbbbbbbbbbbbbbbb\
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\ccccccccccccccccdddddddddddddddd\
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\eeeeeeeeeeeeeeeeffffffffffffffff"#
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{-# INLINE convertByte #-}
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