    {-# LANGUAGE BangPatterns #-}
    {-# LANGUAGE OverloadedStrings #-}
    {-# LANGUAGE Trustworthy #-}
    -- |
    -- Module       : Data.ByteString.Base64
    -- Copyright    : (c) 2019-2020 Emily Pillmore
    -- License      : BSD-style
    --
    -- Maintainer   : Emily Pillmore <emilypi@cohomolo.gy>
    -- Stability    : stable
    -- Portability  : non-portable
    --
    -- This module contains 'Data.ByteString.ByteString'-valued combinators for
    -- implementing the RFC 4648 specification of the Base64
    -- encoding format. This includes lenient decoding variants, as well as
    -- internal and external validation for canonicity.
    --
    module Data.ByteString.Base64
    ( -- * Encoding
      encodeBase64
    , encodeBase64'
      -- * Decoding
    , decodeBase64
    , decodeBase64Lenient
      -- * Validation
    , 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>
    --
    -- === __Examples__:
    --
    -- >>> encodeBase64 "Sun"
    -- "U3Vu"
    --
    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>
    --
    -- === __Examples__:
    --
    -- >>> encodeBase64' "Sun"
    -- "U3Vu"
    --
    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>
    --
    -- === __Examples__:
    --
    -- >>> decodeBase64 "U3Vu"
    -- Right "Sun"
    --
    -- >>> decodeBase64 "U3V"
    -- Left "Base64-encoded bytestring requires padding"
    --
    -- >>> decodebase64 "U3V="
    -- Left "non-canonical encoding detected at offset: 2"
    --
    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
    $ ForeignPtr Word8 -> ByteString -> IO (Either Text ByteString)
    decodeBase64_ ForeignPtr Word8
    decodeB64Table ByteString
    bs
      where
        !r :: Int
    r = Int
    l Int -> Int -> Int
    forall a. Integral a => a -> a -> a
    `rem` Int
    4
    {-# 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.
    --
    -- === __Examples__:
    --
    -- >>> decodeBase64Lenient "U3Vu"
    -- "Sun"
    --
    -- >>> decodeBase64Lenient "U3V"
    -- "Su"
    --
    -- >>> decodebase64Lenient "U3V="
    -- "Su"
    --
    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.
    --
    -- This function will also detect non-canonical encodings such as @ZE==@, which are
    -- externally valid Base64url-encoded values, but are internally inconsistent "impossible"
    -- values.
    --
    -- === __Examples__:
    --
    -- >>> isBase64 "U3Vu"
    -- True
    --
    -- >>> isBase64 "U3V"
    -- False
    --
    -- >>> isBase64 "U3V="
    -- False
    --
    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'.
    --
    -- === __Examples__:
    --
    -- >>> isValidBase64 "U3Vu"
    -- True
    --
    -- >>> isValidBase64 "U3V"
    -- True
    --
    -- >>> isValidBase64 "U3V="
    -- True
    --
    -- >>> isValidBase64 "%"
    -- False
    --
    isValidBase64 :: ByteString -> Bool
    isValidBase64 :: ByteString -> Bool
    isValidBase64 = ByteString -> ByteString -> Bool
    validateBase64 ByteString
    "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"
    {-# inline isValidBase64 #-}