import Data.Bits
import Data.Word
import Numeric

fI :: (Integral a, Num b) => a -> b
fI = fromIntegral

crc32 :: [Word8] -> Word32
crc32 xs = foldl k 0xFFFFFFFF xs `xor` 0xFFFFFFFF
  where
    f x = if x .&. 1 /= 0
             then x `shiftR` 1 `xor` 0xEDB88320
             else x `shiftR` 1
    g x = iterate f x !! 8
    t = map g [0..255]
    k c x = t !! fI ((c `xor` fI x) .&. 0xFF) `xor` (c `shiftR` 8)

crc8 :: [Word8] -> Word8
crc8 xs = foldl k 0xFF xs `xor` 0xFF
  where
    f x = if x .&. 0x80 /= 0
             then x `shiftL` 1 `xor` 0x1D
             else x `shiftL` 1
    g x = iterate f x !! 8
    t = map g [0..255]
    k c x = t !! fI ((c `xor` x) .&. 0xFF) `xor` (c `shiftL` 8)

main :: IO ()
main = do
    putStrLn $ showHex (crc8 [0x04,0x53,0x5F,0x0A,0x6C,0x20,0xB1,0xFF,0x00]) ""