encoding/Data/Encoding/KOI8R.hs
Henning Guenther 0e4f3e9d2b Made DynEncoding an instance of Eq
darcs-hash:20080101224724-a4fee-4ff48f9729414a347da55cb95223429baf0587c1
2008-01-01 14:47:24 -08:00

62 lines
2.3 KiB
Haskell

{-# LANGUAGE DeriveDataTypeable #-}
module Data.Encoding.KOI8R
(KOI8R(..)) where
import Control.Exception (throwDyn)
import Data.Array.Unboxed
import Data.Char (ord,chr)
import qualified Data.ByteString.Lazy as Lazy
import Data.Map hiding (map,(!))
import Data.Word
import Prelude hiding (lookup)
import Data.Typeable
import Data.Encoding.Base
data KOI8R = KOI8R deriving (Eq,Show,Typeable)
koi8rArr :: UArray Word8 Char
koi8rArr = listArray (128,255) koi8rList
koi8rMap :: Map Char Word8
koi8rMap = fromList (zip koi8rList [0..])
koi8rList :: [Char]
koi8rList =
['\x2500','\x2502','\x250c','\x2510','\x2514','\x2518','\x251c','\x2524'
,'\x252c','\x2534','\x253c','\x2580','\x2584','\x2588','\x258c','\x2590'
,'\x2591','\x2592','\x2593','\x2320','\x25a0','\x2219','\x221a','\x2248'
,'\x2264','\x2265','\x00a0','\x2321','\x00b0','\x00b2','\x00b7','\x00f7'
,'\x2550','\x2551','\x2552','\x0451','\x2553','\x2554','\x2555','\x2556'
,'\x2557','\x2558','\x2559','\x255a','\x255b','\x255c','\x255d','\x255e'
,'\x255f','\x2560','\x2561','\x0401','\x2562','\x2563','\x2564','\x2565'
,'\x2566','\x2567','\x2568','\x2569','\x256a','\x256b','\x256c','\x00a9'
,'\x044e','\x0430','\x0431','\x0446','\x0434','\x0435','\x0444','\x0433'
,'\x0445','\x0438','\x0439','\x043a','\x043b','\x043c','\x043d','\x043e'
,'\x043f','\x044f','\x0440','\x0441','\x0442','\x0443','\x0436','\x0432'
,'\x044c','\x044b','\x0437','\x0448','\x044d','\x0449','\x0447','\x044a'
,'\x042e','\x0410','\x0411','\x0426','\x0414','\x0415','\x0424','\x0413'
,'\x0425','\x0418','\x0419','\x041a','\x041b','\x041c','\x041d','\x041e'
,'\x041f','\x042f','\x0420','\x0421','\x0422','\x0423','\x0416','\x0412'
,'\x042c','\x042b','\x0417','\x0428','\x042d','\x0429','\x0427','\x042a']
koi8rDecode :: Word8 -> Char
koi8rDecode ch
| ch < 128 = chr $ fromIntegral ch
| otherwise = koi8rArr!ch
koi8rEncode :: Char -> Word8
koi8rEncode ch
| ch < '\128' = fromIntegral $ ord ch
| otherwise = case lookup ch koi8rMap of
Just w -> w
Nothing -> throwDyn (HasNoRepresentation ch)
instance Encoding KOI8R where
encode _ = encodeSinglebyte koi8rEncode
encodeLazy _ = encodeSinglebyteLazy koi8rEncode
encodable _ c = (c < '\128') || (member c koi8rMap)
decode _ = decodeSinglebyte koi8rDecode
decodeLazy _ str = concatMap (decodeSinglebyte koi8rDecode) (Lazy.toChunks str)
decodable _ = const True