module Codec.Binary.Base32Hex
( encode
, decode
, decode'
, chop
, unchop
) where
import Control.Monad
import Data.Array
import Data.Bits
import Data.Maybe
import Data.Word
import qualified Data.Map as M
import qualified Codec.Binary.Base32 as Base32
encodeArray :: Array Word8 Char
encodeArray = array (0, 32) [
(0, '0'), (1, '1'), (2, '2'), (3, '3'), (4, '4'),
(5, '5'), (6, '6'), (7, '7'), (8, '8'), (9, '9'),
(10, 'A'), (11, 'B'), (12, 'C'), (13, 'D'), (14, 'E'),
(15, 'F'), (16, 'G'), (17, 'H'), (18, 'I'), (19, 'J'),
(20, 'K'), (21, 'L'), (22, 'M'), (23, 'N'), (24, 'O'),
(25, 'P'), (26, 'Q'), (27, 'R'), (28, 'S'), (29, 'T'),
(30, 'U'), (31, 'V') ]
decodeMap :: M.Map Char Word8
decodeMap = M.fromList [
('0', 0), ('1', 1), ('2', 2), ('3', 3), ('4', 4),
('5', 5), ('6', 6), ('7', 7), ('8', 8), ('9', 9),
('A', 10), ('B', 11), ('C', 12), ('D', 13), ('E', 14),
('F', 15), ('G', 16), ('H', 17), ('I', 18), ('J', 19),
('K', 20), ('L', 21), ('M', 22), ('N', 23), ('O', 24),
('P', 25), ('Q', 26), ('R', 27), ('S', 28), ('T', 29),
('U', 30), ('V', 31)
]
encode :: [Word8]
-> String
encode [] = ""
encode [o] = let
i1 = o `shiftR` 3
i2 = o `shiftL` 2 .&. 0x1f
in (encodeArray ! i1) : (encodeArray ! i2) : "======"
encode [o1, o2] = let
i1 = o1 `shiftR` 3
i2 = (o1 `shiftL` 2 .|. o2 `shiftR` 6) .&. 0x1f
i3 = o2 `shiftR` 1 .&. 0x1f
i4 = o2 `shiftL` 4 .&. 0x1f
in foldr (\ i s -> (encodeArray ! i) : s) "====" [i1, i2, i3, i4]
encode [o1, o2, o3] = let
i1 = o1 `shiftR` 3
i2 = (o1 `shiftL` 2 .|. o2 `shiftR` 6) .&. 0x1f
i3 = o2 `shiftR` 1 .&. 0x1f
i4 = (o2 `shiftL` 4 .|. o3 `shiftR` 4) .&. 0x1f
i5 = o3 `shiftL` 1 .&. 0x1f
in foldr (\ i s -> (encodeArray ! i) : s) "===" [i1, i2, i3, i4, i5]
encode [o1, o2, o3, o4] = let
i1 = o1 `shiftR` 3
i2 = (o1 `shiftL` 2 .|. o2 `shiftR` 6) .&. 0x1f
i3 = o2 `shiftR` 1 .&. 0x1f
i4 = (o2 `shiftL` 4 .|. o3 `shiftR` 4) .&. 0x1f
i5 = (o3 `shiftL` 1 .|. o4 `shiftR` 7) .&. 0x1f
i6 = o4 `shiftR` 2 .&. 0x1f
i7 = o4 `shiftL` 3 .&. 0x1f
in foldr (\ i s -> (encodeArray ! i) : s) "=" [i1, i2, i3, i4, i5, i6, i7]
encode (o1:o2:o3:o4:o5:os) = let
i1 = o1 `shiftR` 3
i2 = (o1 `shiftL` 2 .|. o2 `shiftR` 6) .&. 0x1f
i3 = o2 `shiftR` 1 .&. 0x1f
i4 = (o2 `shiftL` 4 .|. o3 `shiftR` 4) .&. 0x1f
i5 = (o3 `shiftL` 1 .|. o4 `shiftR` 7) .&. 0x1f
i6 = o4 `shiftR` 2 .&. 0x1f
i7 = (o4 `shiftL` 3 .|. o5 `shiftR` 5) .&. 0x1f
i8 = o5 .&. 0x1f
in (foldr (\ i s -> (encodeArray ! i) : s) "" [i1, i2, i3, i4, i5, i6, i7, i8]) ++ (encode os)
decode' :: String
-> [Maybe Word8]
decode' = let
dec [] = []
dec [Just eo1, Just eo2] = [Just (eo1 `shiftL` 3 .|. eo2 `shiftR` 2)]
dec [Just eo1, Just eo2, Just eo3, Just eo4] = let
o1 = eo1 `shiftL` 3 .|. eo2 `shiftR` 2
o2 = eo2 `shiftL` 6 .|. eo3 `shiftL` 1 .|. eo4 `shiftR` 4
in [Just o1, Just o2]
dec [Just eo1, Just eo2, Just eo3, Just eo4, Just eo5] = let
o1 = eo1 `shiftL` 3 .|. eo2 `shiftR` 2
o2 = eo2 `shiftL` 6 .|. eo3 `shiftL` 1 .|. eo4 `shiftR` 4
o3 = eo4 `shiftL` 4 .|. eo5 `shiftR` 1
in [Just o1, Just o2, Just o3]
dec [Just eo1, Just eo2, Just eo3, Just eo4, Just eo5, Just eo6, Just eo7] = let
o1 = eo1 `shiftL` 3 .|. eo2 `shiftR` 2
o2 = eo2 `shiftL` 6 .|. eo3 `shiftL` 1 .|. eo4 `shiftR` 4
o3 = eo4 `shiftL` 4 .|. eo5 `shiftR` 1
o4 = eo5 `shiftL` 7 .|. eo6 `shiftL` 2 .|. eo7 `shiftR` 3
in [Just o1, Just o2, Just o3, Just o4]
dec (Just eo1:Just eo2:Just eo3:Just eo4:Just eo5:Just eo6:Just eo7:Just eo8:eos) = let
o1 = eo1 `shiftL` 3 .|. eo2 `shiftR` 2
o2 = eo2 `shiftL` 6 .|. eo3 `shiftL` 1 .|. eo4 `shiftR` 4
o3 = eo4 `shiftL` 4 .|. eo5 `shiftR` 1
o4 = eo5 `shiftL` 7 .|. eo6 `shiftL` 2 .|. eo7 `shiftR` 3
o5 = eo7 `shiftL` 5 .|. eo8
in Just o1:Just o2:Just o3:Just o4:Just o5:(dec eos)
dec _ = [Nothing]
in
dec . map (flip M.lookup decodeMap) . takeWhile (/= '=')
decode :: String
-> Maybe [Word8]
decode = sequence . decode'
chop :: Int
-> String
-> [String]
chop = Base32.chop
unchop :: [String]
-> String
unchop = Base32.unchop