    {-# LANGUAGE BangPatterns #-}
    {-# LANGUAGE OverloadedStrings #-}
    {-# LANGUAGE Trustworthy #-}
    -- |
    -- Module       : Data.ByteString.Lazy.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.Lazy.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.Lazy.Base64.URL
    ( -- * Encoding
      encodeBase64
    , encodeBase64'
    , encodeBase64Unpadded
    , encodeBase64Unpadded'
      -- * Decoding
    , decodeBase64
    , decodeBase64Unpadded
    , decodeBase64Padded
    , decodeBase64Lenient
      -- * Validation
    , isBase64Url
    , isValidBase64Url
    ) where

    import Prelude hiding (all, elem)

    import qualified Data.ByteString as BS
    import qualified Data.ByteString.Base64.URL as B64U
    import Data.ByteString.Base64.Internal.Utils (reChunkN)
    import Data.ByteString.Lazy (elem, fromChunks, toChunks)
    import Data.ByteString.Lazy.Internal (ByteString(..))
    import Data.Either (isRight)
    import qualified Data.Text as T
    import qualified Data.Text.Lazy as TL
    import qualified Data.Text.Lazy.Encoding as TL

    -- | 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 -> TL.Text
    encodeBase64 :: ByteString -> Text
    encodeBase64 = ByteString -> Text
    TL.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' = [ByteString] -> ByteString
    fromChunks
      ([ByteString] -> ByteString)
    -> (ByteString -> [ByteString]) -> ByteString -> ByteString
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . (ByteString -> ByteString) -> [ByteString] -> [ByteString]
    forall a b. (a -> b) -> [a] -> [b]
    forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
    fmap ByteString -> ByteString
    B64U.encodeBase64'
      ([ByteString] -> [ByteString])
    -> (ByteString -> [ByteString]) -> ByteString -> [ByteString]
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . Int -> [ByteString] -> [ByteString]
    reChunkN Int
    3
      ([ByteString] -> [ByteString])
    -> (ByteString -> [ByteString]) -> ByteString -> [ByteString]
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . ByteString -> [ByteString]
    toChunks

    -- | 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 T.Text ByteString
    decodeBase64 :: ByteString -> Either Text ByteString
    decodeBase64 = (ByteString -> ByteString)
    -> Either Text ByteString -> Either Text ByteString
    forall a b. (a -> b) -> Either Text a -> Either Text b
    forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
    fmap ([ByteString] -> ByteString
    fromChunks ([ByteString] -> ByteString)
    -> (ByteString -> [ByteString]) -> ByteString -> ByteString
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . (ByteString -> [ByteString] -> [ByteString]
    forall a. a -> [a] -> [a]
    :[]))
      (Either Text ByteString -> Either Text ByteString)
    -> (ByteString -> Either Text ByteString)
    -> ByteString
    -> Either Text ByteString
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . ByteString -> Either Text ByteString
    B64U.decodeBase64
      (ByteString -> Either Text ByteString)
    -> (ByteString -> ByteString)
    -> ByteString
    -> Either Text ByteString
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . [ByteString] -> ByteString
    BS.concat
      ([ByteString] -> ByteString)
    -> (ByteString -> [ByteString]) -> ByteString -> ByteString
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . ByteString -> [ByteString]
    toChunks
    {-# 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 -> TL.Text
    encodeBase64Unpadded :: ByteString -> Text
    encodeBase64Unpadded = ByteString -> Text
    TL.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' = [ByteString] -> ByteString
    fromChunks
      ([ByteString] -> ByteString)
    -> (ByteString -> [ByteString]) -> ByteString -> ByteString
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . (ByteString -> ByteString) -> [ByteString] -> [ByteString]
    forall a b. (a -> b) -> [a] -> [b]
    forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
    fmap ByteString -> ByteString
    B64U.encodeBase64Unpadded'
      ([ByteString] -> [ByteString])
    -> (ByteString -> [ByteString]) -> ByteString -> [ByteString]
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . Int -> [ByteString] -> [ByteString]
    reChunkN Int
    3
      ([ByteString] -> [ByteString])
    -> (ByteString -> [ByteString]) -> ByteString -> [ByteString]
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . ByteString -> [ByteString]
    toChunks

    -- | 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 T.Text ByteString
    decodeBase64Unpadded :: ByteString -> Either Text ByteString
    decodeBase64Unpadded = (ByteString -> ByteString)
    -> Either Text ByteString -> Either Text ByteString
    forall a b. (a -> b) -> Either Text a -> Either Text b
    forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
    fmap ([ByteString] -> ByteString
    fromChunks ([ByteString] -> ByteString)
    -> (ByteString -> [ByteString]) -> ByteString -> ByteString
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . (ByteString -> [ByteString] -> [ByteString]
    forall a. a -> [a] -> [a]
    :[]))
      (Either Text ByteString -> Either Text ByteString)
    -> (ByteString -> Either Text ByteString)
    -> ByteString
    -> Either Text ByteString
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . ByteString -> Either Text ByteString
    B64U.decodeBase64Unpadded
      (ByteString -> Either Text ByteString)
    -> (ByteString -> ByteString)
    -> ByteString
    -> Either Text ByteString
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . [ByteString] -> ByteString
    BS.concat
      ([ByteString] -> ByteString)
    -> (ByteString -> [ByteString]) -> ByteString -> ByteString
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . ByteString -> [ByteString]
    toChunks
    {-# 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 T.Text ByteString
    decodeBase64Padded :: ByteString -> Either Text ByteString
    decodeBase64Padded = (ByteString -> ByteString)
    -> Either Text ByteString -> Either Text ByteString
    forall a b. (a -> b) -> Either Text a -> Either Text b
    forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
    fmap ([ByteString] -> ByteString
    fromChunks ([ByteString] -> ByteString)
    -> (ByteString -> [ByteString]) -> ByteString -> ByteString
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . (ByteString -> [ByteString] -> [ByteString]
    forall a. a -> [a] -> [a]
    :[]))
      (Either Text ByteString -> Either Text ByteString)
    -> (ByteString -> Either Text ByteString)
    -> ByteString
    -> Either Text ByteString
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . ByteString -> Either Text ByteString
    B64U.decodeBase64Padded
      (ByteString -> Either Text ByteString)
    -> (ByteString -> ByteString)
    -> ByteString
    -> Either Text ByteString
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . [ByteString] -> ByteString
    BS.concat
      ([ByteString] -> ByteString)
    -> (ByteString -> [ByteString]) -> ByteString -> ByteString
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . ByteString -> [ByteString]
    toChunks
    {-# 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 = [ByteString] -> ByteString
    fromChunks
        ([ByteString] -> ByteString)
    -> (ByteString -> [ByteString]) -> ByteString -> ByteString
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . (ByteString -> ByteString) -> [ByteString] -> [ByteString]
    forall a b. (a -> b) -> [a] -> [b]
    forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
    fmap ByteString -> ByteString
    B64U.decodeBase64Lenient
        ([ByteString] -> [ByteString])
    -> (ByteString -> [ByteString]) -> ByteString -> [ByteString]
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . Int -> [ByteString] -> [ByteString]
    reChunkN Int
    4
        ([ByteString] -> [ByteString])
    -> (ByteString -> [ByteString]) -> ByteString -> [ByteString]
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . (ByteString -> ByteString) -> [ByteString] -> [ByteString]
    forall a b. (a -> b) -> [a] -> [b]
    forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
    fmap ((Word8 -> Bool) -> ByteString -> ByteString
    BS.filter ((Word8 -> ByteString -> Bool) -> ByteString -> Word8 -> Bool
    forall a b c. (a -> b -> c) -> b -> a -> c
    flip Word8 -> ByteString -> Bool
    elem ByteString
    "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_="))
        ([ByteString] -> [ByteString])
    -> (ByteString -> [ByteString]) -> ByteString -> [ByteString]
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . ByteString -> [ByteString]
    toChunks
    {-# INLINE decodeBase64Lenient #-}

    -- | Tell whether a 'ByteString' is Base64url-encoded.
    --
    -- === __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] -> Bool
    go ([ByteString] -> Bool)
    -> (ByteString -> [ByteString]) -> ByteString -> Bool
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . ByteString -> [ByteString]
    toChunks
      where
        go :: [ByteString] -> Bool
    go [] = Bool
    True
        go [ByteString
    c] = ByteString -> Bool
    B64U.isValidBase64Url ByteString
    c
        go (ByteString
    c:[ByteString]
    cs) = -- note the lack of padding char
          (Word8 -> Bool) -> ByteString -> Bool
    BS.all ((Word8 -> ByteString -> Bool) -> ByteString -> Word8 -> Bool
    forall a b c. (a -> b -> c) -> b -> a -> c
    flip Word8 -> ByteString -> Bool
    elem ByteString
    "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_") ByteString
    c
          Bool -> Bool -> Bool
    && [ByteString] -> Bool
    go [ByteString]
    cs
    {-# INLINE isValidBase64Url #-}