{-
Copyright (C) 2008 Joachim Breitner

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; see the file COPYING.  If not, write to
the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
Boston, MA 02110-1301, USA.
-}


module StringCrypto 
	( md5
	, sha1
	) where

import qualified Data.Digest.SHA1 as SHA1
import qualified Data.Digest.MD5 as MD5
import Data.Word
import Data.Char

md5 :: String -> String
md5 = toHex1 . MD5.hash . map (fromIntegral. ord)

toHex1 :: [Word8] -> String
toHex1 = concatMap showAsHex1

showAsHex1 :: Word8 -> String
showAsHex1 n = showIt 2 n ""
   where
    showIt :: Int -> Word8 -> String -> String
    showIt 0 _ r = r
    showIt i x r = case quotRem x 16 of
                       (y, z) -> let c = intToDigit (fromIntegral z)
                                 in c `seq` showIt (i-1) y (c:r)



sha1 :: String -> String
sha1 = toHex2 . SHA1.hash . map (fromIntegral . ord)

toHex2 :: SHA1.Word160 -> String
toHex2 (SHA1.Word160 a b c d e)
 = concatMap showAsHex2 [a, b, c, d, e]

showAsHex2 :: Word32 -> String
showAsHex2 n = showIt 8 n ""
   where
    showIt :: Int -> Word32 -> String -> String
    showIt 0 _ r = r
    showIt i x r = case quotRem x 16 of
                       (y, z) -> let c = intToDigit (fromIntegral z)
                                 in c `seq` showIt (i-1) y (c:r)