{-# LANGUAGE CPP #-}
#if __GLASGOW_HASKELL__ >= 702
{-# LANGUAGE Trustworthy #-}
#endif

-- |
-- Module      : Data.ByteString.Base64.Lazy
-- Copyright   : (c) 2012 Ian Lynagh
--
-- License     : BSD-style
-- Maintainer  : Emily Pillmore <emilypi@cohomolo.gy>,
--               Herbert Valerio Riedel <hvr@gnu.org>,
--               Mikhail Glushenkov <mikhail.glushenkov@gmail.com>
-- Stability   : experimental
-- Portability : GHC
--
-- Fast and efficient encoding and decoding of base64-encoded
-- lazy bytestrings.
--
-- @since 1.0.0.0
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 :: ByteString -> ByteString
encode = [StrictByteString] -> ByteString
L.fromChunks ([StrictByteString] -> ByteString)
-> (ByteString -> [StrictByteString]) -> ByteString -> ByteString
forall b c a. (b -> c) -> (a -> b) -> a -> c
. (StrictByteString -> StrictByteString)
-> [StrictByteString] -> [StrictByteString]
forall a b. (a -> b) -> [a] -> [b]
map StrictByteString -> StrictByteString
B64.encode ([StrictByteString] -> [StrictByteString])
-> (ByteString -> [StrictByteString])
-> ByteString
-> [StrictByteString]
forall b c a. (b -> c) -> (a -> b) -> a -> c
. Int -> [StrictByteString] -> [StrictByteString]
reChunkIn Int
3 ([StrictByteString] -> [StrictByteString])
-> (ByteString -> [StrictByteString])
-> ByteString
-> [StrictByteString]
forall b c a. (b -> c) -> (a -> b) -> a -> c
. ByteString -> [StrictByteString]
L.toChunks

-- | Decode a base64-encoded string.  This function strictly follows
-- the specification in
-- <http://tools.ietf.org/rfc/rfc4648 RFC 4648>.
decode :: L.ByteString -> Either String L.ByteString
decode :: ByteString -> Either String ByteString
decode ByteString
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 StrictByteString -> Either String StrictByteString
B64.decode (StrictByteString -> Either String StrictByteString)
-> StrictByteString -> Either String StrictByteString
forall a b. (a -> b) -> a -> b
$ [StrictByteString] -> StrictByteString
S.concat ([StrictByteString] -> StrictByteString)
-> [StrictByteString] -> StrictByteString
forall a b. (a -> b) -> a -> b
$ ByteString -> [StrictByteString]
L.toChunks ByteString
b of
           Left String
err -> String -> Either String ByteString
forall a b. a -> Either a b
Left String
err
           Right StrictByteString
b' -> ByteString -> Either String ByteString
forall a b. b -> Either a b
Right (ByteString -> Either String ByteString)
-> ByteString -> Either String ByteString
forall a b. (a -> b) -> a -> b
$ [StrictByteString] -> ByteString
L.fromChunks [StrictByteString
b']

-- | Decode a base64-encoded string.  This function is lenient in
-- following the specification from
-- <http://tools.ietf.org/rfc/rfc4648 RFC 4648>, and will not generate
-- parse errors no matter how poor its input.
decodeLenient :: L.ByteString -> L.ByteString
decodeLenient :: ByteString -> ByteString
decodeLenient = [StrictByteString] -> ByteString
L.fromChunks ([StrictByteString] -> ByteString)
-> (ByteString -> [StrictByteString]) -> ByteString -> ByteString
forall b c a. (b -> c) -> (a -> b) -> a -> c
. (StrictByteString -> StrictByteString)
-> [StrictByteString] -> [StrictByteString]
forall a b. (a -> b) -> [a] -> [b]
map StrictByteString -> StrictByteString
B64.decodeLenient ([StrictByteString] -> [StrictByteString])
-> (ByteString -> [StrictByteString])
-> ByteString
-> [StrictByteString]
forall b c a. (b -> c) -> (a -> b) -> a -> c
. Int -> [StrictByteString] -> [StrictByteString]
reChunkIn Int
4 ([StrictByteString] -> [StrictByteString])
-> (ByteString -> [StrictByteString])
-> ByteString
-> [StrictByteString]
forall b c a. (b -> c) -> (a -> b) -> a -> c
. ByteString -> [StrictByteString]
L.toChunks
              (ByteString -> [StrictByteString])
-> (ByteString -> ByteString) -> ByteString -> [StrictByteString]
forall b c a. (b -> c) -> (a -> b) -> a -> c
. (Char -> Bool) -> ByteString -> ByteString
LC.filter Char -> Bool
goodChar
    where -- We filter out and '=' padding here, but B64.decodeLenient
          -- handles that
          goodChar :: Char -> Bool
goodChar Char
c = Char -> Bool
isDigit Char
c Bool -> Bool -> Bool
|| Char -> Bool
isAsciiUpper Char
c Bool -> Bool -> Bool
|| Char -> Bool
isAsciiLower Char
c
                                 Bool -> Bool -> Bool
|| Char
c Char -> Char -> Bool
forall a. Eq a => a -> a -> Bool
== Char
'+' Bool -> Bool -> Bool
|| Char
c Char -> Char -> Bool
forall a. Eq a => a -> a -> Bool
== Char
'/'