ref: 5bcc30b7813a7bd15717f44d57cfb0dcbab3c87e
dir: /Tools/Decompress.hs/
import qualified Data.Map as M
import Data.Char
import System.Environment
import System.IO
import Debug.Trace
type Table = M.Map Int [Char]
toChar :: Int -> Char
toChar i = chr (i + 32)
initTable :: Table
initTable = M.fromList $ [(c, [toChar c]) | c <- [0..94] ] ++ [(95, "\n")]
decompress :: Table -> [Int] -> [Char]
decompress t (old:is) =
let s = t M.! old
c = head s
in s ++ decompress' t old c is
decompress' :: Table -> Int -> Char -> [Int] -> [Char]
decompress' _ _ _ [] = []
decompress' _ _ _ [0] = []
decompress' t old c (n:is) =
let s = case M.lookup n t of
Nothing -> (t M.! old) ++ [c]
Just x -> x
out = s
c' = head s
t' = M.insert (M.size t) (t M.! old ++ [c']) t
old' = n
in out ++ decompress' t' old' c' is
fromBytes :: [Int] -> [Int]
fromBytes [] = []
fromBytes (b1:b2:b3:bs) =
let i = b1 + 256 * b2 + 256 * 256 * b3
i1 = i `rem` 4096
i2 = i `quot` 4096
in i1 : i2 : fromBytes bs
main :: IO ()
main = do
h <- openBinaryFile "bytes" ReadMode
bs <- map fromEnum <$> hGetContents h
let is = fromBytes bs
cs = decompress initTable is
putStr cs