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[internal] add a way to convert bytearray to hexadecimal bytearray

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This commit is contained in:
Vincent Hanquez 2015-04-30 06:08:21 +01:00
parent b497737ef1
commit 84c05617a3
1 changed files with 25 additions and 4 deletions
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29
Crypto/Internal/Hex.hs
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@ -13,12 +13,14 @@
{-# LANGUAGE BangPatterns #-}
module Crypto.Internal.Hex
( showHexadecimal
, toHexadecimal
) where
import Crypto.Internal.Compat
import Data.Word
import GHC.Prim
import GHC.Types
import GHC.Word
import Foreign.Storable
import Foreign.Ptr (Ptr)
@ -28,14 +30,32 @@ showHexadecimal ptr len = loop 0
loop i
| i == len = []
| otherwise =
let b = fromIntegral (byteIndex i)
in toEnum (r tableHi b) : toEnum (r tableLo b) : loop (i+1)
let !(W8# b) = byteIndex i
(# w1, w2 #) = convertByte b
in wToChar w1 : wToChar w2 : loop (i+1)
wToChar :: Word# -> Char
wToChar w = toEnum (I# (word2Int# w))
byteIndex :: Int -> Word8
byteIndex i = unsafeDoIO (peekByteOff ptr i)
r :: Addr# -> Int -> Int
r table (I# index) = I# (word2Int# (indexWord8OffAddr# table index))
toHexadecimal :: Ptr Word8 -> Ptr Word8 -> Int -> IO ()
toHexadecimal bout bin n = loop 0
where loop i
| i == n = return ()
| otherwise = do
(W8# w) <- peekByteOff bin i
let (# w1, w2 #) = convertByte w
pokeByteOff bout (i * 2) (W8# w1)
pokeByteOff bout (i * 2 + 1) (W8# w2)
loop (i+1)
convertByte :: Word# -> (# Word#, Word# #)
convertByte b = (# r tableHi b, r tableLo b #)
where
r :: Addr# -> Word# -> Word#
r table index = indexWord8OffAddr# table (word2Int# index)
!tableLo =
"0123456789abcdef0123456789abcdef\
@ -55,3 +75,4 @@ showHexadecimal ptr len = loop 0
\aaaaaaaaaaaaaaaabbbbbbbbbbbbbbbb\
\ccccccccccccccccdddddddddddddddd\
\eeeeeeeeeeeeeeeeffffffffffffffff"#
{-# INLINE convertByte #-}