    {-# LANGUAGE BangPatterns #-}
    {-# LANGUAGE OverloadedStrings #-}
    {-# LANGUAGE Trustworthy #-}
    -- |
    -- Module       : Data.ByteString.Base64.URL
    -- 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 Base64url
    -- encoding format. This includes strictly padded/unpadded and lenient decoding
    -- variants, as well as internal and external validation for canonicity.
    --
    module Data.ByteString.Base64.URL
    ( -- * Encoding
      encodeBase64
    , encodeBase64'
    , encodeBase64Unpadded
    , encodeBase64Unpadded'
      -- * Decoding
    , decodeBase64
    , decodeBase64Unpadded
    , decodeBase64Padded
    , decodeBase64Lenient
      -- * Validation
    , isBase64Url
    , isValidBase64Url
    ) where

    import qualified Data.ByteString as BS
    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 a Base64url 'Text' value with padding.
    --
    -- See: <https://tools.ietf.org/html/rfc4648#section-5 RFC-4648 section 5>
    --
    -- === __Examples__:
    --
    -- >>> encodeBase64 "<<?>>"
    -- "PDw_Pj4="
    --
    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' as a Base64url 'ByteString' value with padding.
    --
    -- See: <https://tools.ietf.org/html/rfc4648#section-5 RFC-4648 section 5>
    --
    -- === __Examples__:
    --
    -- >>> encodeBase64' "<<?>>"
    -- "PDw_Pj4="
    --
    encodeBase64' :: ByteString -> ByteString
    encodeBase64' :: ByteString -> ByteString
    encodeBase64' = EncodingTable -> ByteString -> ByteString
    encodeBase64_ EncodingTable
    base64UrlTable

    -- | Decode a padded Base64url encoded 'ByteString' value. If its length is not a multiple
    -- of 4, then padding chars will be added to fill out the input to a multiple of
    -- 4 for safe decoding as Base64url-encoded values are optionally padded.
    --
    -- For a decoder that fails on unpadded input of incorrect size, use 'decodeBase64Unpadded'.
    --
    -- See: <https://tools.ietf.org/html/rfc4648#section-4 RFC-4648 section 4>
    --
    -- === __Examples__:
    --
    -- >>> decodeBase64 "PDw_Pj4="
    -- Right "<<?>>"
    --
    -- >>> decodeBase64 "PDw_Pj4"
    -- Right "<<?>>"
    --
    -- >>> decodeBase64 "PDw-Pg="
    -- Left "Base64-encoded bytestring has invalid padding"
    --
    -- >>> decodeBase64 "PDw-Pg"
    -- Right "<<>>"
    --
    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
    0 = 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
    decodeB64UrlTable ByteString
    bs
        | Int
    r Int -> Int -> Bool
    forall a. Eq a => a -> a -> Bool
    == Int
    2 = 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
    decodeB64UrlTable (ByteString -> ByteString -> ByteString
    BS.append ByteString
    bs ByteString
    "==")
        | Int
    r Int -> Int -> Bool
    forall a. Eq a => a -> a -> Bool
    == Int
    3 = ByteString -> IO (Either Text ByteString) -> Either Text ByteString
    validateLastPad ByteString
    bs (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
    decodeB64UrlTable (ByteString -> ByteString -> ByteString
    BS.append ByteString
    bs ByteString
    "=")
        | Bool
    otherwise = Text -> Either Text ByteString
    forall a b. a -> Either a b
    Left Text
    "Base64-encoded bytestring has invalid size"
      where
        !r :: Int
    r = Int
    l Int -> Int -> Int
    forall a. Integral a => a -> a -> a
    `rem` Int
    4
    {-# INLINE decodeBase64 #-}

    -- | Encode a 'ByteString' value as Base64url 'Text' without padding. Note that for Base64url,
    -- padding is optional. If you call this function, you will simply be encoding
    -- as Base64url and stripping padding chars from the output.
    --
    -- See: <https://tools.ietf.org/html/rfc4648#section-3.2 RFC-4648 section 3.2>
    --
    -- === __Examples__:
    --
    -- >>> encodeBase64Unpadded "<<?>>"
    -- "PDw_Pj4"
    --
    encodeBase64Unpadded :: ByteString -> Text
    encodeBase64Unpadded :: ByteString -> Text
    encodeBase64Unpadded = ByteString -> Text
    T.decodeUtf8 (ByteString -> Text)
    -> (ByteString -> ByteString) -> ByteString -> Text
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . ByteString -> ByteString
    encodeBase64Unpadded'
    {-# INLINE encodeBase64Unpadded #-}

    -- | Encode a 'ByteString' value as Base64url without padding. Note that for Base64url,
    -- padding is optional. If you call this function, you will simply be encoding
    -- as Base64url and stripping padding chars from the output.
    --
    -- See: <https://tools.ietf.org/html/rfc4648#section-3.2 RFC-4648 section 3.2>
    --
    -- === __Examples__:
    --
    -- >>> encodeBase64Unpadded' "<<?>>"
    -- "PDw_Pj4"
    --
    encodeBase64Unpadded' :: ByteString -> ByteString
    encodeBase64Unpadded' :: ByteString -> ByteString
    encodeBase64Unpadded' = EncodingTable -> ByteString -> ByteString
    encodeBase64Nopad_ EncodingTable
    base64UrlTable

    -- | Decode an unpadded Base64url-encoded 'ByteString' value. Input strings are
    -- required to be unpadded, and will undergo validation prior to decoding to
    -- confirm.
    --
    -- In general, unless unpadded Base64url is explicitly required, it is
    -- safer to call 'decodeBase64'.
    --
    -- See: <https://tools.ietf.org/html/rfc4648#section-4 RFC-4648 section 4>
    --
    -- === __Examples__:
    --
    -- >>> decodeBase64Unpadded "PDw_Pj4"
    -- Right "<<?>>"
    --
    -- >>> decodeBase64Unpadded "PDw_Pj4="
    -- Left "Base64-encoded bytestring has invalid padding"
    --
    decodeBase64Unpadded :: ByteString -> Either Text ByteString
    decodeBase64Unpadded :: ByteString -> Either Text ByteString
    decodeBase64Unpadded 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
    0 = ByteString -> IO (Either Text ByteString) -> Either Text ByteString
    validateLastPad ByteString
    bs (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
    decodeB64UrlTable ByteString
    bs
        | Int
    r Int -> Int -> Bool
    forall a. Eq a => a -> a -> Bool
    == Int
    2 = ByteString -> IO (Either Text ByteString) -> Either Text ByteString
    validateLastPad ByteString
    bs (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
    decodeB64UrlTable (ByteString -> ByteString -> ByteString
    BS.append ByteString
    bs ByteString
    "==")
        | Int
    r Int -> Int -> Bool
    forall a. Eq a => a -> a -> Bool
    == Int
    3 = ByteString -> IO (Either Text ByteString) -> Either Text ByteString
    validateLastPad ByteString
    bs (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
    decodeB64UrlTable (ByteString -> ByteString -> ByteString
    BS.append ByteString
    bs ByteString
    "=")
        | Bool
    otherwise = Text -> Either Text ByteString
    forall a b. a -> Either a b
    Left Text
    "Base64-encoded bytestring has invalid size"
      where
        !r :: Int
    r = Int
    l Int -> Int -> Int
    forall a. Integral a => a -> a -> a
    `rem` Int
    4
    {-# INLINE decodeBase64Unpadded #-}

    -- | Decode a padded Base64url-encoded 'ByteString' value. Input strings are
    -- required to be correctly padded, and will be validated prior to decoding
    -- to confirm.
    --
    -- In general, unless padded Base64url is explicitly required, it is
    -- safer to call 'decodeBase64'.
    --
    -- See: <https://tools.ietf.org/html/rfc4648#section-4 RFC-4648 section 4>
    --
    -- === __Examples__:
    --
    -- >>> decodeBase64Padded "PDw_Pj4="
    -- Right "<<?>>"
    --
    -- >>> decodeBase64Padded "PDw_Pj4"
    -- Left "Base64-encoded bytestring requires padding"
    --
    decodeBase64Padded :: ByteString -> Either Text ByteString
    decodeBase64Padded :: ByteString -> Either Text ByteString
    decodeBase64Padded 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
    decodeB64UrlTable ByteString
    bs
      where
        !r :: Int
    r = Int
    l Int -> Int -> Int
    forall a. Integral a => a -> a -> a
    `rem` Int
    4
    {-# INLINE decodeBase64Padded #-}

    -- | Leniently decode an unpadded Base64url-encoded 'ByteString'. 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 "PDw_Pj4="
    -- "<<?>>"
    --
    -- >>> decodeBase64Lenient "PDw_%%%$}Pj4"
    -- "<<?>>"
    --
    decodeBase64Lenient :: ByteString -> ByteString
    decodeBase64Lenient :: ByteString -> ByteString
    decodeBase64Lenient = ForeignPtr Word8 -> ByteString -> ByteString
    decodeBase64Lenient_ ForeignPtr Word8
    decodeB64UrlTable
    {-# INLINE decodeBase64Lenient #-}

    -- | Tell whether a 'ByteString' is encoded in padded /or/ unpadded Base64url format.
    --
    -- 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__:
    --
    -- >>> isBase64Url "PDw_Pj4="
    -- True
    --
    -- >>> isBase64Url "PDw_Pj4"
    -- True
    --
    -- >>> isBase64Url "PDw_Pj"
    -- False
    --
    isBase64Url :: ByteString -> Bool
    isBase64Url :: ByteString -> Bool
    isBase64Url ByteString
    bs = ByteString -> Bool
    isValidBase64Url 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 isBase64Url #-}

    -- | Tell whether a 'ByteString' is a valid Base64url 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 'isBase64Url'.
    --
    -- === __Examples__:
    --
    -- >>> isValidBase64Url "PDw_Pj4="
    -- True
    --
    -- >>> isValidBase64Url "PDw_Pj"
    -- True
    --
    -- >>> isValidBase64Url "%"
    -- False
    --
    isValidBase64Url :: ByteString -> Bool
    isValidBase64Url :: ByteString -> Bool
    isValidBase64Url = ByteString -> ByteString -> Bool
    validateBase64Url ByteString
    "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_"
    {-# INLINE isValidBase64Url #-}