{-# LANGUAGE BangPatterns #-}
{-# LANGUAGE OverloadedStrings #-}
-- |
-- Module       : Data.ByteString.Base64
-- Copyright    : (c) 2019-2020 Emily Pillmore
-- License      : BSD-style
--
-- Maintainer   : Emily Pillmore <emilypi@cohomolo.gy>
-- Stability    : Experimental
-- Portability  : portable
--
-- This module contains the combinators implementing the
-- RFC 4648 specification for the Base64 encoding including
-- unpadded and lenient variants
--
module Data.ByteString.Base64
( encodeBase64
, encodeBase64'
, decodeBase64
, decodeBase64Lenient
, isBase64
, isValidBase64
) where


import Data.ByteString.Internal (ByteString(..))
import Data.ByteString.Base64.Internal
import Data.ByteString.Base64.Internal.Head
import Data.ByteString.Base64.Internal.Tables
import Data.Either (isRight)
import Data.Text (Text)
import qualified Data.Text.Encoding as T

import System.IO.Unsafe


-- | Encode a 'ByteString' value as Base64 'Text' with padding.
--
-- See: <https://tools.ietf.org/html/rfc4648#section-4 RFC-4648 section 4>
--
encodeBase64 :: ByteString -> Text
encodeBase64 :: ByteString -> Text
encodeBase64 = ByteString -> Text
T.decodeUtf8 (ByteString -> Text)
-> (ByteString -> ByteString) -> ByteString -> Text
forall b c a. (b -> c) -> (a -> b) -> a -> c
. ByteString -> ByteString
encodeBase64'
{-# INLINE encodeBase64 #-}

-- | Encode a 'ByteString' value as a Base64 'ByteString'  value with padding.
--
-- See: <https://tools.ietf.org/html/rfc4648#section-4 RFC-4648 section 4>
--
encodeBase64' :: ByteString -> ByteString
encodeBase64' :: ByteString -> ByteString
encodeBase64' = EncodingTable -> ByteString -> ByteString
encodeBase64_ EncodingTable
base64Table
{-# INLINE encodeBase64' #-}

-- | Decode a padded Base64-encoded 'ByteString' value.
--
-- See: <https://tools.ietf.org/html/rfc4648#section-4 RFC-4648 section 4>
--
decodeBase64 :: ByteString -> Either Text ByteString
decodeBase64 :: ByteString -> Either Text ByteString
decodeBase64 bs :: ByteString
bs@(PS ForeignPtr Word8
_ Int
_ Int
l)
    | Int
l Int -> Int -> Bool
forall a. Eq a => a -> a -> Bool
== Int
0 = ByteString -> Either Text ByteString
forall a b. b -> Either a b
Right ByteString
bs
    | Int
r Int -> Int -> Bool
forall a. Eq a => a -> a -> Bool
== Int
1 = Text -> Either Text ByteString
forall a b. a -> Either a b
Left Text
"Base64-encoded bytestring has invalid size"
    | Int
r Int -> Int -> Bool
forall a. Eq a => a -> a -> Bool
/= Int
0 = Text -> Either Text ByteString
forall a b. a -> Either a b
Left Text
"Base64-encoded bytestring requires padding"
    | Bool
otherwise = IO (Either Text ByteString) -> Either Text ByteString
forall a. IO a -> a
unsafeDupablePerformIO (IO (Either Text ByteString) -> Either Text ByteString)
-> IO (Either Text ByteString) -> Either Text ByteString
forall a b. (a -> b) -> a -> b
$ Int
-> ForeignPtr Word8 -> ByteString -> IO (Either Text ByteString)
decodeBase64_ Int
dlen ForeignPtr Word8
decodeB64Table ByteString
bs
  where
    q :: Int
q = Int
l Int -> Int -> Int
forall a. Integral a => a -> a -> a
`quot` Int
4
    r :: Int
r = Int
l Int -> Int -> Int
forall a. Integral a => a -> a -> a
`rem` Int
4
    dlen :: Int
dlen = Int
q Int -> Int -> Int
forall a. Num a => a -> a -> a
* Int
3
{-# INLINE decodeBase64 #-}

-- | Leniently decode an unpadded Base64-encoded 'ByteString' value. This function
-- will not generate parse errors. If input data contains padding chars,
-- then the input will be parsed up until the first pad character.
--
-- __Note:__ This is not RFC 4648-compliant.
--
decodeBase64Lenient :: ByteString -> ByteString
decodeBase64Lenient :: ByteString -> ByteString
decodeBase64Lenient = ForeignPtr Word8 -> ByteString -> ByteString
decodeBase64Lenient_ ForeignPtr Word8
decodeB64Table
{-# INLINE decodeBase64Lenient #-}

-- | Tell whether a 'ByteString' value is base64 encoded.
--
isBase64 :: ByteString -> Bool
isBase64 :: ByteString -> Bool
isBase64 ByteString
bs = ByteString -> Bool
isValidBase64 ByteString
bs Bool -> Bool -> Bool
&& Either Text ByteString -> Bool
forall a b. Either a b -> Bool
isRight (ByteString -> Either Text ByteString
decodeBase64 ByteString
bs)
{-# INLINE isBase64 #-}

-- | Tell whether a 'ByteString' value is a valid Base64 format.
--
-- This will not tell you whether or not this is a correct Base64url representation,
-- only that it conforms to the correct shape. To check whether it is a true
-- Base64 encoded 'ByteString' value, use 'isBase64'.
--
isValidBase64 :: ByteString -> Bool
isValidBase64 :: ByteString -> Bool
isValidBase64 = ByteString -> ByteString -> Bool
validateBase64 ByteString
"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"
{-# INLINE isValidBase64 #-}