module Crypto.Hash.Utils
( toHex
) where
import Data.ByteString (ByteString)
import qualified Data.ByteString.Internal as B
import GHC.Prim
import GHC.Types
import GHC.Word
import Foreign.ForeignPtr (withForeignPtr)
import Foreign.Ptr (plusPtr, castPtr)
import Foreign.Storable (poke, peek)
import Crypto.Hash.Utils.Cpu
import Data.Bits (testBit)
toHex :: ByteString -> ByteString
toHex (B.PS fp off len) = B.unsafeCreate (len*2) $ \d ->
withForeignPtr fp $ \s -> start d (s `plusPtr` off)
where start db sb
| use32Hex && (len `testBit` 0) == False = loop32 db sb
| otherwise = loop8 db sb
where end = sb `plusPtr` len
loop32 d s
| s == end = return ()
| otherwise = do b1 <- fromIntegral `fmap` (peek s :: IO Word8)
b2 <- fromIntegral `fmap` (peek (s `plusPtr` 1) :: IO Word8)
poke (castPtr d) (to32 b1 b2)
loop32 (d `plusPtr` 4) (s `plusPtr` 2)
loop8 d s
| s == end = return ()
| otherwise = do b <- fromIntegral `fmap` (peek s :: IO Word8)
poke d (r tableHi b)
poke (d `plusPtr` 1) (r tableLo b)
loop8 (d `plusPtr` 2) (s `plusPtr` 1)
to32 (I# i1) (I# i2) = W32# (or# (or# (or# hi2 lo2) hi1) lo1)
where hi2 = uncheckedShiftL# (indexWord8OffAddr# tableLo i2) 24#
lo2 = uncheckedShiftL# (indexWord8OffAddr# tableHi i2) 16#
hi1 = uncheckedShiftL# (indexWord8OffAddr# tableLo i1) 8#
lo1 = indexWord8OffAddr# tableHi i1
r :: Addr# -> Int -> Word8
r table (I# index) = W8# (indexWord8OffAddr# table index)
!tableLo =
"0123456789abcdef0123456789abcdef\
\0123456789abcdef0123456789abcdef\
\0123456789abcdef0123456789abcdef\
\0123456789abcdef0123456789abcdef\
\0123456789abcdef0123456789abcdef\
\0123456789abcdef0123456789abcdef\
\0123456789abcdef0123456789abcdef\
\0123456789abcdef0123456789abcdef"#
!tableHi =
"00000000000000001111111111111111\
\22222222222222223333333333333333\
\44444444444444445555555555555555\
\66666666666666667777777777777777\
\88888888888888889999999999999999\
\aaaaaaaaaaaaaaaabbbbbbbbbbbbbbbb\
\ccccccccccccccccdddddddddddddddd\
\eeeeeeeeeeeeeeeeffffffffffffffff"#