-- | Decode Content-Transfer-Encoding Qouted-Printable
module Dqp(decodeQuotedPrintable) where
import Data.Char(chr,isHexDigit,digitToInt)

decodeQuotedPrintable :: String -> String
decodeQuotedPrintable = dqp

dqp  [] = []
dqp ('=':'\r':'\n':cs) = dqp cs
dqp ('=':'\n':cs) = dqp cs
dqp ('=':c1:c2:cs) | isHexDigit c1 && isHexDigit c2 = hex c1 c2:dqp cs
dqp (c:cs) = c:dqp cs

hex c1 c2 = chr (16*digitToInt c1 + digitToInt c2)