Base16.hs

-- |
-- Module       : Data.ByteString.Base16
-- Copyright    : (c) 2020-2026 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 Base16
-- encoding format. This includes lenient decoding variants, as well as
-- internal and external validation for canonicity.
--
module Data.ByteString.Base16
( encodeBase16
, encodeBase16'
, decodeBase16
, decodeBase16'
, decodeBase16Untyped
, decodeBase16Lenient
, parseBase16
) where


import Data.Base16.Types
import Data.ByteString (ByteString)
import Data.ByteString.Base16.Internal.Head
import Data.Text (Text)
import qualified Data.Text.Encoding as T

-- $setup
--
-- >>> import Data.Base16.Types
-- >>> :set -XOverloadedStrings
--

-- | Encode a 'ByteString' value as Base16 'Text'
--
-- See: <https://tools.ietf.org/html/rfc4648#section-8 RFC-4648 section 8>
--
-- === __Examples__:
--
-- >>> encodeBase16 "Sun"
-- "53756e"
--
encodeBase16 :: ByteString -> Base16 Text
encodeBase16 = fmap T.decodeUtf8 . encodeBase16'
{-# INLINE encodeBase16 #-}

-- | Encode a 'ByteString' value as a Base16 'ByteString' value
--
-- See: <https://tools.ietf.org/html/rfc4648#section-8 RFC-4648 section 8>
--
-- === __Examples__:
--
-- >>> encodeBase16' "Sun"
-- "53756e"
--
encodeBase16' :: ByteString -> Base16 ByteString
encodeBase16' = assertBase16 . encodeBase16_
{-# INLINE encodeBase16' #-}

-- | Decode a Base16-encoded 'ByteString' value.
--
-- See: <https://tools.ietf.org/html/rfc4648#section-8 RFC-4648 section 8>
--
-- === __Examples__:
--
-- >>> decodeBase16 $ assertBase16 "53756e"
-- "Sun"
--
decodeBase16 :: Base16 ByteString -> ByteString
decodeBase16 = decodeBase16Typed_
{-# INLINE decodeBase16 #-}

-- | Decode Base16 'Text'.
--
-- See: <https://tools.ietf.org/html/rfc4648#section-8 RFC-4648 section 8>
--
-- === __Examples__:
--
-- >>> decodeBase16' $ assertBase16 "53756e"
-- "Sun"
--
decodeBase16' :: Base16 Text -> ByteString
decodeBase16' = decodeBase16Typed_ . fmap T.encodeUtf8
{-# INLINE decodeBase16' #-}

-- | Decode an untyped Base16-encoded 'ByteString' value with error-checking.
--
-- See: <https://tools.ietf.org/html/rfc4648#section-8 RFC-4648 section 8>
--
-- === __Examples__:
--
-- >>> decodeBase16Untyped "53756e"
-- Right "Sun"
--
-- >>> decodeBase16Untyped "6x"
-- Left "invalid character at offset: 1"
--
decodeBase16Untyped :: ByteString -> Either Text ByteString
decodeBase16Untyped = decodeBase16_
{-# INLINE decodeBase16Untyped #-}

-- | Decode a Base16-encoded 'ByteString' value leniently, using a
-- strategy that never fails
--
-- N.B.: this is not RFC 4648-compliant
--
-- === __Examples__:
--
-- >>> decodeBase16Lenient "53756e"
-- "Sun"
--
-- >>> decodeBase16Lenient "6x6x"
-- "f"
--
decodeBase16Lenient :: ByteString -> ByteString
decodeBase16Lenient = decodeBase16Lenient_
{-# INLINE decodeBase16Lenient #-}

-- | Validate an untyped Base16 value and retain its encoded representation.
--
-- Accepts even-length ASCII hexadecimal input, including upper-case and
-- mixed-case digits. Empty input is valid. The original input is preserved,
-- and errors match 'decodeBase16Untyped'.
--
-- === __Examples__:
--
-- >>> parseBase16 "666f6"
-- Left "invalid bytestring size"
--
-- >>> parseBase16 "666F"
-- Right "666F"
--
-- >>> fmap decodeBase16 (parseBase16 "666F")
-- Right "fo"
--
-- >>> parseBase16 "6x"
-- Left "invalid character at offset: 1"
--
-- @since 1.0
--
parseBase16 :: ByteString -> Either Text (Base16 ByteString)
parseBase16 bs = assertBase16 bs <$ decodeBase16Untyped bs
{-# INLINE parseBase16 #-}