{-# 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 #-}