{-# LANGUAGE CPP,TemplateHaskell,DeriveDataTypeable #-}
{- | This module implements Windows Codepage number 1258 which encodes the vietnamese language.
     See <http://en.wikipedia.org/wiki/CP1258> for more information.
module Data.Encoding.CP1258
	(CP1258(..)) where

import Data.Array ((!),Array)
import Data.Word (Word8)
import Data.ByteString (all)
import Data.Map (Map,lookup,member)
import Data.Encoding.Base
import Prelude hiding (lookup,all)
import Control.Exception (throwDyn)
import Data.Typeable

data CP1258 = CP1258 deriving (Eq,Show,Typeable)

instance Encoding CP1258 where
	encode _ = encodeSinglebyte (\c -> case lookup c encodeMap of
		Just v -> v
		Nothing -> throwDyn (HasNoRepresentation c))
	encodable _ c = member c encodeMap
	decode _ = decodeSinglebyte (decodeArr!)
	decodable _ = all (\w -> decodeArr!w /= '\xFFFD')

decodeArr :: Array Word8 Char
#ifndef __HADDOCK__
decodeArr = $(decodingArray "CP1258.TXT")

encodeMap :: Map Char Word8
#ifndef __HADDOCK__
encodeMap =  $(encodingMap "CP1258.TXT")