    {-# LANGUAGE BangPatterns #-}
    {-# LANGUAGE OverloadedStrings #-}
    {-# LANGUAGE DataKinds #-}
    {-# LANGUAGE TypeFamilies #-}
    -- |
    -- Module       : Data.ByteString.Base64.URL
    -- Copyright    : (c) 2019-2023 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 url-safe Base64 (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
    , decodeBase64Untyped
    , decodeBase64Unpadded
    , decodeBase64UnpaddedUntyped
    , decodeBase64Padded
    , decodeBase64PaddedUntyped
    , decodeBase64Lenient
      -- * Validation
    , isBase64Url
    , isValidBase64Url
    ) where

    import Data.Base64.Types
    import Data.Base64.Types.Internal

    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

    -- $setup
    --
    -- >>> import Data.Base64.Types
    -- >>> :set -XOverloadedStrings
    -- >>> :set -XTypeApplications
    -- >>> :set -XDataKinds
    --

    -- | 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 -> Base64 'UrlPadded Text
    encodeBase64 :: ByteString -> Base64 'UrlPadded Text
    encodeBase64 = (ByteString -> Text)
    -> Base64 'UrlPadded ByteString -> Base64 'UrlPadded Text
    forall a b. (a -> b) -> Base64 'UrlPadded a -> Base64 'UrlPadded b
    forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
    fmap ByteString -> Text
    T.decodeUtf8 (Base64 'UrlPadded ByteString -> Base64 'UrlPadded Text)
    -> (ByteString -> Base64 'UrlPadded ByteString)
    -> ByteString
    -> Base64 'UrlPadded Text
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . ByteString -> Base64 'UrlPadded 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 -> Base64 'UrlPadded ByteString
    encodeBase64' :: ByteString -> Base64 'UrlPadded ByteString
    encodeBase64' = ByteString -> Base64 'UrlPadded ByteString
    forall (k :: Alphabet) a. a -> Base64 k a
    assertBase64 (ByteString -> Base64 'UrlPadded ByteString)
    -> (ByteString -> ByteString)
    -> ByteString
    -> Base64 'UrlPadded ByteString
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . EncodingTable -> ByteString -> ByteString
    encodeBase64_ EncodingTable
    base64UrlTable

    -- | Decode a Base64url encoded 'ByteString' value, either padded or unpadded.
    -- The correct decoding function is dispatched based on the existence of padding.
    --
    -- For typed values:
    --   - If a padded value is required, use 'decodeBase64Padded'
    --   - If an unpadded value is required, use 'decodeBase64Unpadded'
    --
    -- See: <https://tools.ietf.org/html/rfc4648#section-4 RFC-4648 section 4>
    --
    -- === __Examples__:
    --
    -- >>> decodeBase64 $ assertBase64 @'UrlPadded "PDw_Pj4="
    -- "<<?>>"
    --
    -- >>> decodeBase64 $ assertBase64 @'UrlUnpadded "PDw_Pj4"
    -- "<<?>>"
    --
    decodeBase64
      :: UrlAlphabet k
      => Base64 k ByteString
      -> ByteString
    decodeBase64 :: forall (k :: Alphabet).
    UrlAlphabet k =>
    Base64 k ByteString -> ByteString
    decodeBase64 b64 :: Base64 k ByteString
    b64@(Base64 ByteString
    bs)
      | Bool -> Bool
    not (Bool -> Bool) -> Bool -> Bool
    forall a b. (a -> b) -> a -> b
    $ ByteString -> Bool
    BS.null ByteString
    bs, HasCallStack => ByteString -> Word8
    ByteString -> Word8
    BS.last ByteString
    bs Word8 -> Word8 -> Bool
    forall a. Eq a => a -> a -> Bool
    == Word8
    0x3d = Base64 'UrlPadded ByteString -> ByteString
    decodeBase64Padded (Base64 'UrlPadded ByteString -> ByteString)
    -> Base64 'UrlPadded ByteString -> ByteString
    forall a b. (a -> b) -> a -> b
    $ Base64 k ByteString -> Base64 'UrlPadded ByteString
    forall (j :: Alphabet) (k :: Alphabet) a. Base64 k a -> Base64 j a
    coerceBase64 Base64 k ByteString
    b64
      | Bool
    otherwise = Base64 'UrlUnpadded ByteString -> ByteString
    decodeBase64Unpadded (Base64 'UrlUnpadded ByteString -> ByteString)
    -> Base64 'UrlUnpadded ByteString -> ByteString
    forall a b. (a -> b) -> a -> b
    $ Base64 k ByteString -> Base64 'UrlUnpadded ByteString
    forall (j :: Alphabet) (k :: Alphabet) a. Base64 k a -> Base64 j a
    coerceBase64 Base64 k ByteString
    b64
    {-# inline decodeBase64 #-}

    -- | Decode an untyped 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 to decode untyped values of incorrect size:
    --   - If a padded value is required, use 'decodeBase64PaddedUntyped'
    --   - If an unpadded value is required, use 'decodeBase64UnpaddedUntyped'
    --
    -- See: <https://tools.ietf.org/html/rfc4648#section-4 RFC-4648 section 4>
    --
    -- === __Examples__:
    --
    -- >>> decodeBase64Untyped "PDw_Pj4="
    -- Right "<<?>>"
    --
    -- >>> decodeBase64Untyped "PDw_Pj4"
    -- Right "<<?>>"
    --
    -- >>> decodeBase64Untyped "PDw-Pg="
    -- Left "Base64-encoded bytestring has invalid padding"
    --
    -- >>> decodeBase64Untyped "PDw-Pg"
    -- Right "<<>>"
    --
    decodeBase64Untyped :: ByteString -> Either Text ByteString
    decodeBase64Untyped :: ByteString -> Either Text ByteString
    decodeBase64Untyped 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
    forall a. Monoid a => a
    mempty
      | 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 -> IO (Either Text ByteString))
    -> ByteString -> IO (Either Text ByteString)
    forall a b. (a -> b) -> a -> b
    $ 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 -> IO (Either Text ByteString))
    -> ByteString -> IO (Either Text ByteString)
    forall a b. (a -> b) -> a -> b
    $ 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 decodeBase64Untyped #-}

    -- | 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 -> Base64 'UrlUnpadded Text
    encodeBase64Unpadded :: ByteString -> Base64 'UrlUnpadded Text
    encodeBase64Unpadded = (ByteString -> Text)
    -> Base64 'UrlUnpadded ByteString -> Base64 'UrlUnpadded Text
    forall a b.
    (a -> b) -> Base64 'UrlUnpadded a -> Base64 'UrlUnpadded b
    forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
    fmap ByteString -> Text
    T.decodeUtf8 (Base64 'UrlUnpadded ByteString -> Base64 'UrlUnpadded Text)
    -> (ByteString -> Base64 'UrlUnpadded ByteString)
    -> ByteString
    -> Base64 'UrlUnpadded Text
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . ByteString -> Base64 'UrlUnpadded 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 -> Base64 'UrlUnpadded ByteString
    encodeBase64Unpadded' :: ByteString -> Base64 'UrlUnpadded ByteString
    encodeBase64Unpadded' = ByteString -> Base64 'UrlUnpadded ByteString
    forall (k :: Alphabet) a. a -> Base64 k a
    assertBase64 (ByteString -> Base64 'UrlUnpadded ByteString)
    -> (ByteString -> ByteString)
    -> ByteString
    -> Base64 'UrlUnpadded ByteString
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . 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.
    --
    -- See: <https://tools.ietf.org/html/rfc4648#section-4 RFC-4648 section 4>
    --
    -- === __Examples__:
    --
    -- >>> decodeBase64Unpadded $ assertBase64 @'UrlUnpadded "PDw_Pj4"
    -- "<<?>>"
    --
    decodeBase64Unpadded :: Base64 'UrlUnpadded ByteString -> ByteString
    decodeBase64Unpadded :: Base64 'UrlUnpadded ByteString -> ByteString
    decodeBase64Unpadded b64 :: Base64 'UrlUnpadded ByteString
    b64@(Base64 (PS ForeignPtr Word8
    _ Int
    _ !Int
    l))
        | Int
    r Int -> Int -> Bool
    forall a. Eq a => a -> a -> Bool
    == Int
    2 = Base64 'UrlPadded ByteString -> ByteString
    decodeBase64Padded (Base64 'UrlPadded ByteString -> ByteString)
    -> Base64 'UrlPadded ByteString -> ByteString
    forall a b. (a -> b) -> a -> b
    $ Base64 'UrlUnpadded ByteString -> Base64 'UrlPadded ByteString
    forall (j :: Alphabet) (k :: Alphabet) a. Base64 k a -> Base64 j a
    coerceBase64 (Base64 'UrlUnpadded ByteString -> Base64 'UrlPadded ByteString)
    -> Base64 'UrlUnpadded ByteString -> Base64 'UrlPadded ByteString
    forall a b. (a -> b) -> a -> b
    $ (ByteString -> ByteString -> ByteString
    `BS.append` ByteString
    "==") (ByteString -> ByteString)
    -> Base64 'UrlUnpadded ByteString -> Base64 'UrlUnpadded ByteString
    forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
    <$> Base64 'UrlUnpadded ByteString
    b64
        | Int
    r Int -> Int -> Bool
    forall a. Eq a => a -> a -> Bool
    == Int
    3 = Base64 'UrlPadded ByteString -> ByteString
    decodeBase64Padded (Base64 'UrlPadded ByteString -> ByteString)
    -> Base64 'UrlPadded ByteString -> ByteString
    forall a b. (a -> b) -> a -> b
    $ Base64 'UrlUnpadded ByteString -> Base64 'UrlPadded ByteString
    forall (j :: Alphabet) (k :: Alphabet) a. Base64 k a -> Base64 j a
    coerceBase64 (Base64 'UrlUnpadded ByteString -> Base64 'UrlPadded ByteString)
    -> Base64 'UrlUnpadded ByteString -> Base64 'UrlPadded ByteString
    forall a b. (a -> b) -> a -> b
    $ (ByteString -> ByteString -> ByteString
    `BS.append` ByteString
    "=") (ByteString -> ByteString)
    -> Base64 'UrlUnpadded ByteString -> Base64 'UrlUnpadded ByteString
    forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
    <$> Base64 'UrlUnpadded ByteString
    b64
        | Bool
    otherwise = Base64 'UrlPadded ByteString -> ByteString
    decodeBase64Padded (Base64 'UrlPadded ByteString -> ByteString)
    -> Base64 'UrlPadded ByteString -> ByteString
    forall a b. (a -> b) -> a -> b
    $ Base64 'UrlUnpadded ByteString -> Base64 'UrlPadded ByteString
    forall (j :: Alphabet) (k :: Alphabet) a. Base64 k a -> Base64 j a
    coerceBase64 Base64 'UrlUnpadded ByteString
    b64
      where
        !r :: Int
    r = Int
    l Int -> Int -> Int
    forall a. Integral a => a -> a -> a
    `rem` Int
    4

    -- | Decode a padded, untyped 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 'decodeBase64Untyped'.
    --
    -- See: <https://tools.ietf.org/html/rfc4648#section-4 RFC-4648 section 4>
    --
    -- === __Examples__:
    --
    -- >>> decodeBase64PaddedUntyped "PDw_Pj4="
    -- Right "<<?>>"
    --
    decodeBase64PaddedUntyped :: ByteString -> Either Text ByteString
    decodeBase64PaddedUntyped :: ByteString -> Either Text ByteString
    decodeBase64PaddedUntyped 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
    forall a. Monoid a => a
    mempty
        | 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 decodeBase64PaddedUntyped #-}

    -- | Decode a padded Base64url-encoded 'ByteString' value. Input strings are
    -- required to be correctly padded, and will be validated prior to decoding
    -- to confirm.
    --
    -- See: <https://tools.ietf.org/html/rfc4648#section-4 RFC-4648 section 4>
    --
    -- === __Examples__:
    --
    -- >>> decodeBase64Padded $ assertBase64 @'UrlPadded "PDw_Pj4="
    -- "<<?>>"
    --
    decodeBase64Padded :: Base64 'UrlPadded ByteString -> ByteString
    decodeBase64Padded :: Base64 'UrlPadded ByteString -> ByteString
    decodeBase64Padded = ForeignPtr Word8 -> Base64 'UrlPadded ByteString -> ByteString
    forall (k :: Alphabet).
    ForeignPtr Word8 -> Base64 k ByteString -> ByteString
    decodeBase64Typed_ ForeignPtr Word8
    decodeB64UrlTable
    {-# INLINE decodeBase64Padded #-}

    -- | Decode an unpadded, untyped 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 'decodeBase64Untyped'.
    --
    -- See: <https://tools.ietf.org/html/rfc4648#section-4 RFC-4648 section 4>
    --
    -- === __Examples__:
    --
    -- >>> decodeBase64UnpaddedUntyped "PDw_Pj4"
    -- Right "<<?>>"
    --
    -- >>> decodeBase64UnpaddedUntyped "PDw_Pj4="
    -- Left "Base64-encoded bytestring has invalid padding"
    --
    decodeBase64UnpaddedUntyped :: ByteString -> Either Text ByteString
    decodeBase64UnpaddedUntyped :: ByteString -> Either Text ByteString
    decodeBase64UnpaddedUntyped 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
    forall a. Monoid a => a
    mempty
        | 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 -> IO (Either Text ByteString))
    -> ByteString -> IO (Either Text ByteString)
    forall a b. (a -> b) -> a -> b
    $ 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 -> IO (Either Text ByteString))
    -> ByteString -> IO (Either Text ByteString)
    forall a b. (a -> b) -> a -> b
    $ 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 decodeBase64UnpaddedUntyped #-}

    -- | Leniently decode an unpadded, untyped 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
    decodeBase64Untyped 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 #-}