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diff --git a/src/Codec/Binary/Base16.hs b/src/Codec/Binary/Base16.hs
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+-- |
+-- Module    : Codec.Binary.Base16
+-- Copyright : (c) 2007 Magnus Therning
+-- License   : BSD3
+--
+-- Implemented as specified in RFC 4648 (<http://tools.ietf.org/html/rfc4648>).
+--
+-- Further documentation and information can be found at
+-- <http://www.haskell.org/haskellwiki/Library/Data_encoding>.
+module Codec.Binary.Base16
+    ( EncIncData(..)
+    , EncIncRes(..)
+    , encodeInc
+    , encode
+    , DecIncData(..)
+    , DecIncRes(..)
+    , decodeInc
+    , decode
+    , chop
+    , unchop
+    ) where
+
+import Codec.Binary.Util
+
+import Control.Monad
+import Data.Array
+import Data.Bits
+import Data.Maybe
+import Data.Word
+import qualified Data.Map as M
+
+-- {{{1 enc/dec map
+_encMap =
+    [ (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') ]
+
+-- {{{1 encodeArray
+encodeArray :: Array Word8 Char
+encodeArray = array (0, 64) _encMap
+
+-- {{{1 decodeMap
+decodeMap :: M.Map Char Word8
+decodeMap  = M.fromList [(snd i, fst i) | i <- _encMap]
+
+-- {{{1 encode
+-- | Incremental encoder function.
+encodeInc :: EncIncData -> EncIncRes String
+encodeInc EDone = EFinal []
+encodeInc (EChunk os) = EPart (concat $ map toHex os) encodeInc
+
+-- | Encode data.
+encode :: [Word8] -> String
+encode = encoder encodeInc
+
+-- {{{1 decode
+-- | Incremental decoder function.
+decodeInc :: DecIncData String -> DecIncRes String
+decodeInc d = dI [] d
+    where
+        dec2 cs = let
+                ds = map (flip M.lookup decodeMap) cs
+                es@[e1, e2] = map fromJust ds
+                o = e1 `shiftL` 4 .|. e2
+                allJust = and . map isJust
+            in if allJust ds
+                then Just o
+                else Nothing
+
+        dI [] DDone = DFinal [] []
+        dI lo DDone = DFail [] lo
+        dI lo (DChunk s) = doDec [] (lo ++ s)
+            where
+                doDec acc s'@(c1:c2:cs) = maybe
+                    (DFail acc s')
+                    (\ b -> doDec (acc ++ [b]) cs)
+                    (dec2 [c1, c2])
+                doDec acc s = DPart acc (dI s)
+
+-- | Decode data.
+decode :: String -> Maybe [Word8]
+decode = decoder decodeInc
+
+-- {{{1 chop
+-- | Chop up a string in parts.
+--
+--   The length given is rounded down to the nearest multiple of 2.
+chop :: Int     -- ^ length of individual lines
+    -> String
+    -> [String]
+chop n "" = []
+chop n s = let
+        enc_len | n < 2 = 2
+                | otherwise = n `div` 2 * 2
+    in take enc_len s : chop n (drop enc_len s)
+
+-- {{{1 unchop
+-- | Concatenate the strings into one long string.
+unchop :: [String]
+    -> String
+unchop = foldr (++) ""