stream.hs

import qualified Data.ByteString.Lazy as BL
import Data.Binary.Get
import Data.Word
import Data.Bits
import Data.Char

readArray :: Get [Word8]
readArray = do
    empty <- isEmpty
    if empty
    then return []
    else do
        byte <- getWord8
        rest <- readArray
        return (byte : rest)

decodeCharonCache :: Int -> [Int] -> [Int]
decodeCharonCache i [] = []
decodeCharonCache i (x:xs) =
    [xorVal `xor` x `xor` 0x6A] ++ decodeCharonCache (i + 1) xs
    where
        xorVal = (i `div` 256) `xor` (i `mod` 256)

main :: IO ()
main = do
    input <- BL.getContents
    putStr $ map chr $ decodeCharonCache 0 $ map (\x -> fromIntegral x :: Int) (runGet readArray input)