left codec module

diff --git a/Pipes/Text/Codec.hs b/Pipes/Text/Codec.hs
deleted file mode 100644 (file)
index 070b0d9..0000000
--- a/Pipes/Text/Codec.hs
+++ /dev/null
@@ -1,215 +0,0 @@
-
-{-# LANGUAGE DeriveDataTypeable, RankNTypes, BangPatterns #-}
--- |
--- Copyright: 2014 Michael Thompson, 2011 Michael Snoyman, 2010-2011 John Millikin
--- License: MIT
---
--- Parts of this code were taken from enumerator and conduits, and adapted for pipes.
-
-module Pipes.Text.Codec
-    ( Decoding(..)
-    , streamDecodeUtf8
-    , decodeSomeUtf8
-    , Codec(..)
-    , TextException(..)
-    , utf8
-    , utf16_le
-    , utf16_be
-    , utf32_le
-    , utf32_be
-    ) where
-
-import Data.Bits ((.&.))
-import Data.Char (ord)
-import Data.ByteString as B 
-import Data.ByteString (ByteString)
-import Data.ByteString.Internal as B 
-import Data.ByteString.Char8 as B8
-import Data.Text (Text)
-import qualified Data.Text as T 
-import qualified Data.Text.Encoding as TE 
-import Data.Text.Encoding.Error ()
-import GHC.Word (Word8, Word32)
-import qualified Data.Text.Array as A
-import Data.Word (Word8, Word16)
-import System.IO.Unsafe (unsafePerformIO)
-import qualified Control.Exception as Exc
-import Data.Bits ((.&.), (.|.), shiftL)
-import Data.Typeable
-import Control.Arrow (first)
-import Data.Maybe (catMaybes)
-import Pipes.Text.Internal
-import Pipes
--- | A specific character encoding.
---
--- Since 0.3.0
-data Codec = Codec
-  { codecName :: Text
-  , codecEncode :: Text -> (ByteString, Maybe (TextException, Text))
-  , codecDecode :: ByteString -> Decoding -- (Text, Either (TextException, ByteString) ByteString)
-  }
-
-instance Show Codec where
-    showsPrec d c = showParen (d > 10) $ 
-                    showString "Codec " . shows (codecName c)
-
-data TextException = DecodeException Codec Word8
-                   | EncodeException Codec Char
-                   | LengthExceeded Int
-                   | TextException Exc.SomeException
-    deriving (Show, Typeable)
-instance Exc.Exception TextException
-
-
-toDecoding :: (ByteString -> (Text, Either (TextException, ByteString) ByteString))
-           -> (ByteString -> Decoding)
-toDecoding op = loop B.empty where
-  loop !extra bs0 = case op (B.append extra bs0) of
-                      (txt, Right bs) -> Some txt bs (loop bs)
-                      (txt, Left (_,bs)) -> Other txt bs
--- To do: toDecoding should be inlined in each of the 'Codec' definitions
--- or else Codec changed to the conduit/enumerator definition.  We have
--- altered it to use 'streamDecodeUtf8'
-
-splitSlowly :: (ByteString -> Text)
-            -> ByteString 
-            -> (Text, Either (TextException, ByteString) ByteString)
-splitSlowly dec bytes = valid where
-    valid:_ = catMaybes $ Prelude.map decFirst $ splits (B.length bytes)
-    splits 0 = [(B.empty, bytes)]
-    splits n = B.splitAt n bytes : splits (n - 1)
-    decFirst (a, b) = case tryEvaluate (dec a) of
-        Left _ -> Nothing
-        Right text -> let trouble = case tryEvaluate (dec b) of
-                            Left exc -> Left (TextException exc, b)
-                            Right _  -> Right B.empty 
-                      in Just (text, trouble) -- this case shouldn't occur, 
-                                      -- since splitSlowly is only called
-                                      -- when parsing failed somewhere
-
-utf8 :: Codec
-utf8 = Codec name enc (toDecoding dec) where
-    name = T.pack "UTF-8"
-    enc text = (TE.encodeUtf8 text, Nothing)
-    dec bytes = case decodeSomeUtf8 bytes of (t,b) -> (t, Right b)
-
---     -- Whether the given byte is a continuation byte.
---     isContinuation byte = byte .&. 0xC0 == 0x80
--- 
---     -- The number of continuation bytes needed by the given
---     -- non-continuation byte. Returns -1 for an illegal UTF-8
---     -- non-continuation byte and the whole split quickly must fail so
---     -- as the input is passed to TE.decodeUtf8, which will issue a
---     -- suitable error.
---     required x0
---         | x0 .&. 0x80 == 0x00 = 0
---         | x0 .&. 0xE0 == 0xC0 = 1
---         | x0 .&. 0xF0 == 0xE0 = 2
---         | x0 .&. 0xF8 == 0xF0 = 3
---         | otherwise           = -1
--- 
---     splitQuickly bytes
---         | B.null l || req == -1 = Nothing
---         | req == B.length r = Just (TE.decodeUtf8 bytes, B.empty)
---         | otherwise = Just (TE.decodeUtf8 l', r')
---       where
---         (l, r) = B.spanEnd isContinuation bytes
---         req = required (B.last l)
---         l' = B.init l
---         r' = B.cons (B.last l) r
-
-
-utf16_le :: Codec
-utf16_le = Codec name enc (toDecoding dec) where
-    name = T.pack "UTF-16-LE"
-    enc text = (TE.encodeUtf16LE text, Nothing)
-    dec bytes = case splitQuickly bytes of
-        Just (text, extra) -> (text, Right extra)
-        Nothing -> splitSlowly TE.decodeUtf16LE bytes
-
-    splitQuickly bytes = maybeDecode (loop 0) where
-        maxN = B.length bytes
-
-        loop n |  n      == maxN = decodeAll
-               | (n + 1) == maxN = decodeTo n
-        loop n = let
-            req = utf16Required
-                (B.index bytes n)
-                (B.index bytes (n + 1))
-            decodeMore = loop $! n + req
-            in if n + req > maxN
-                then decodeTo n
-                else decodeMore
-
-        decodeTo n = first TE.decodeUtf16LE (B.splitAt n bytes)
-        decodeAll = (TE.decodeUtf16LE bytes, B.empty)
-
-utf16_be :: Codec
-utf16_be = Codec name enc (toDecoding dec) where
-    name = T.pack "UTF-16-BE"
-    enc text = (TE.encodeUtf16BE text, Nothing)
-    dec bytes = case splitQuickly bytes of
-        Just (text, extra) -> (text, Right extra)
-        Nothing -> splitSlowly TE.decodeUtf16BE bytes
-
-    splitQuickly bytes = maybeDecode (loop 0) where
-        maxN = B.length bytes
-
-        loop n |  n      == maxN = decodeAll
-               | (n + 1) == maxN = decodeTo n
-        loop n = let
-            req = utf16Required
-                (B.index bytes (n + 1))
-                (B.index bytes n)
-            decodeMore = loop $! n + req
-            in if n + req > maxN
-                then decodeTo n
-                else decodeMore
-
-        decodeTo n = first TE.decodeUtf16BE (B.splitAt n bytes)
-        decodeAll = (TE.decodeUtf16BE bytes, B.empty)
-
-utf16Required :: Word8 -> Word8 -> Int
-utf16Required x0 x1 = if x >= 0xD800 && x <= 0xDBFF then 4 else 2 where
-    x :: Word16
-    x = (fromIntegral x1 `shiftL` 8) .|. fromIntegral x0
-
-
-utf32_le :: Codec
-utf32_le = Codec name enc (toDecoding dec) where
-    name = T.pack "UTF-32-LE"
-    enc text = (TE.encodeUtf32LE text, Nothing)
-    dec bs = case utf32SplitBytes TE.decodeUtf32LE bs of
-        Just (text, extra) -> (text, Right extra)
-        Nothing -> splitSlowly TE.decodeUtf32LE bs
-
-
-utf32_be :: Codec
-utf32_be = Codec name enc (toDecoding dec) where
-    name = T.pack "UTF-32-BE"
-    enc text = (TE.encodeUtf32BE text, Nothing)
-    dec bs = case utf32SplitBytes TE.decodeUtf32BE bs of
-        Just (text, extra) -> (text, Right extra)
-        Nothing -> splitSlowly TE.decodeUtf32BE bs
-
-utf32SplitBytes :: (ByteString -> Text)
-                -> ByteString
-                -> Maybe (Text, ByteString)
-utf32SplitBytes dec bytes = split where
-    split = maybeDecode (dec toDecode, extra)
-    len = B.length bytes
-    lenExtra = mod len 4
-
-    lenToDecode = len - lenExtra
-    (toDecode, extra) = if lenExtra == 0
-        then (bytes, B.empty)
-        else B.splitAt lenToDecode bytes
-
-
-tryEvaluate :: a -> Either Exc.SomeException a
-tryEvaluate = unsafePerformIO . Exc.try . Exc.evaluate
-
-maybeDecode :: (a, b) -> Maybe (a, b)
-maybeDecode (a, b) = case tryEvaluate a of
-    Left _ -> Nothing
-    Right _ -> Just (a, b)