{-# LANGUAGE CPP #-} #if __GLASGOW_HASKELL__ >= 702 {-# LANGUAGE Trustworthy #-} #endif -- | -- Module : Data.ByteString.Base64.Lazy -- Copyright : (c) 2012 Ian Lynagh -- -- License : BSD-style -- Maintainer : bos@serpentine.com -- Stability : experimental -- Portability : GHC -- -- Fast and efficient encoding and decoding of base64-encoded -- lazy bytestrings. module Data.ByteString.Base64.Lazy ( encode , decode , decodeLenient ) where import Data.ByteString.Base64.Internal import qualified Data.ByteString.Base64 as B64 import qualified Data.ByteString as S import qualified Data.ByteString.Lazy as L import qualified Data.ByteString.Lazy.Char8 as LC import Data.Char -- | Encode a string into base64 form. The result will always be a -- multiple of 4 bytes in length. encode :: L.ByteString -> L.ByteString encode = L.fromChunks . map B64.encode . reChunkIn 3 . L.toChunks -- | Decode a base64-encoded string. This function strictly follows -- the specification in RFC 4648, -- <http://www.apps.ietf.org/rfc/rfc4648.html>. decode :: L.ByteString -> Either String L.ByteString decode b = -- Returning an Either type means that the entire result will -- need to be in memory at once anyway, so we may as well -- keep it simple and just convert to and from a strict byte -- string -- TODO: Use L.{fromStrict,toStrict} once we can rely on -- a new enough bytestring case B64.decode $ S.concat $ L.toChunks b of Left err -> Left err Right b' -> Right $ L.fromChunks [b'] -- | Decode a base64-encoded string. This function is lenient in -- following the specification from RFC 4648, -- <http://www.apps.ietf.org/rfc/rfc4648.html>, and will not generate -- parse errors no matter how poor its input. decodeLenient :: L.ByteString -> L.ByteString decodeLenient = L.fromChunks . map B64.decodeLenient . reChunkIn 4 . L.toChunks . LC.filter goodChar where -- We filter out and '=' padding here, but B64.decodeLenient -- handles that goodChar c = isAlphaNum c || c == '+' || c == '/'