-----------------------------------------------------------------------------
-- |
-- Module : Data.Digest.MD5
-- Copyright : (c) Dominic Steinitz 2004
-- License : BSD-style (see the file ReadMe.tex)
--
-- Maintainer : dominic.steinitz@blueyonder.co.uk
-- Stability : experimental
-- Portability : portable
--
-- Takes the MD5 module supplied by Ian Lynagh and wraps it so it
-- takes [Octet] and returns [Octet] where the length of the result
-- is always 16.
-- See
-- and .
--
-----------------------------------------------------------------------------
module Network.HTTP.MD5
( hash
, Octet
) where
import Data.List (unfoldr)
import Data.Word (Word8)
import Numeric (readHex)
import Network.HTTP.MD5Aux (md5s, Str(Str))
type Octet = Word8
-- | Take [Octet] and return [Octet] according to the standard.
-- The length of the result is always 16 octets or 128 bits as required
-- by the standard.
hash :: [Octet] -> [Octet]
hash xs =
unfoldr f $ md5s $ Str $ map (toEnum . fromIntegral) xs
where f :: String -> Maybe (Octet,String)
f [] = Nothing
f [x] = f ['0',x]
f (x:y:zs) = Just (a,zs)
where [(a,_)] = readHex (x:y:[])