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|
-- |
-- Copyright : (c) Sam Truzjan 2013
-- License : BSD3
-- Maintainer : pxqr.sta@gmail.com
-- Stability : stable
-- Portability : portable
--
-- Efficient encoding and decoding of base32 encoded bytestring
-- according to RFC 4648. <http://tools.ietf.org/html/rfc4648>
--
-- This module recommended to be imported as
-- @import Data.ByteString.Base32 as Base32@ to avoid name clashes
-- with @Data.Binary@ or @Data.ByteString.Base64@ modules.
--
{-# LANGUAGE BangPatterns #-}
module Data.ByteString.Base32
( Base32
, encode
, decode
, decodeLenient
) where
import Data.ByteString as BS
import Data.ByteString.Base32.Internal
import Data.List as L
-- | Base32 encoded bytestring.
type Base32 = ByteString
encW5 :: Word5 -> Word8
encW5 !x
| x <= 25 = 65 + x
| otherwise = 24 + x
{-# INLINE encW5 #-}
encTable :: EncTable
encTable = BS.pack $ L.map encW5 [0..31]
-- | Encode an arbitrary bytestring into (upper case) base32 form.
encode :: ByteString -> Base32
encode = unpack5 encTable
decW5 :: Word8 -> Word5
decW5 !x
| x < 50 {- c2w '2' -} = invIx
| x <= 55 {- c2w '7' -} = x - 24 {- c2w '2' - 26 -}
| x < 65 {- c2w 'A' -} = invIx
| x <= 90 {- c2w 'Z' -} = x - 65 {- c2w 'A' -}
| x < 97 {- c2w 'a' -} = invIx
| x <= 122 {- c2w 'z' -} = x - 97 {- c2w 'a' -}
| otherwise = invIx
{-# INLINE decW5 #-}
decTable :: ByteString
decTable = BS.pack $ L.map decW5 [minBound .. maxBound]
-- | Decode a base32 encoded bytestring. This functions is
-- case-insensitive and do not require correct padding.
decode :: Base32 -> Either String ByteString
decode = pack5 decTable
-- | The same as 'decode' but with additional leniency: decodeLenient
-- will skip non-alphabet characters.
decodeLenient :: Base32 -> Either String ByteString
decodeLenient = pack5Lenient decTable
|
