-{-# OPTIONS_GHC -fno-implicit-prelude -funbox-strict-fields #-}
+{-# LANGUAGE CPP, NoImplicitPrelude, PatternGuards #-}
+{-# OPTIONS_GHC -funbox-strict-fields #-}
+
-----------------------------------------------------------------------------
-- |
-- Module : GHC.IO.Encoding
-----------------------------------------------------------------------------
module GHC.IO.Encoding (
- BufferCodec(..), TextEncoding(..), TextEncoder, TextDecoder,
+ BufferCodec(..), TextEncoding(..), TextEncoder, TextDecoder, CodingProgress(..),
latin1, latin1_encode, latin1_decode,
utf8, utf8_bom,
utf16, utf16le, utf16be,
utf32, utf32le, utf32be,
- localeEncoding,
+ localeEncoding, fileSystemEncoding, foreignEncoding,
+ char8,
mkTextEncoding,
) where
import GHC.Base
--import GHC.IO
+import GHC.IO.Exception
import GHC.IO.Buffer
+import GHC.IO.Encoding.Failure
import GHC.IO.Encoding.Types
import GHC.Word
#if !defined(mingw32_HOST_OS)
import qualified GHC.IO.Encoding.Iconv as Iconv
+#else
+import qualified GHC.IO.Encoding.CodePage as CodePage
+import Text.Read (reads)
#endif
import qualified GHC.IO.Encoding.Latin1 as Latin1
import qualified GHC.IO.Encoding.UTF8 as UTF8
import qualified GHC.IO.Encoding.UTF16 as UTF16
import qualified GHC.IO.Encoding.UTF32 as UTF32
-#if defined(mingw32_HOST_OS)
+import Data.List
import Data.Maybe
-import GHC.IO.Exception
-#endif
-- -----------------------------------------------------------------------------
utf32be = UTF32.utf32be
-- | The Unicode encoding of the current locale
-localeEncoding :: TextEncoding
+localeEncoding :: TextEncoding
+
+-- | The Unicode encoding of the current locale, but allowing arbitrary
+-- undecodable bytes to be round-tripped through it.
+--
+-- This 'TextEncoding' is used to decode and encode command line arguments
+-- and environment variables on non-Windows platforms.
+--
+-- On Windows, this encoding *should not* be used if possible because
+-- the use of code pages is deprecated: Strings should be retrieved
+-- via the "wide" W-family of UTF-16 APIs instead
+fileSystemEncoding :: TextEncoding
+
+-- | The Unicode encoding of the current locale, but where undecodable
+-- bytes are replaced with their closest visual match. Used for
+-- the 'CString' marshalling functions in "Foreign.C.String"
+foreignEncoding :: TextEncoding
+
#if !defined(mingw32_HOST_OS)
localeEncoding = Iconv.localeEncoding
+fileSystemEncoding = Iconv.mkLocaleEncoding RoundtripFailure
+foreignEncoding = Iconv.mkLocaleEncoding IgnoreCodingFailure
#else
-localeEncoding = Latin1.latin1
+localeEncoding = CodePage.localeEncoding
+fileSystemEncoding = CodePage.mkLocaleEncoding RoundtripFailure
+foreignEncoding = CodePage.mkLocaleEncoding IgnoreCodingFailure
#endif
+-- | An encoding in which Unicode code points are translated to bytes
+-- by taking the code point modulo 256. When decoding, bytes are
+-- translated directly into the equivalent code point.
+--
+-- This encoding never fails in either direction. However, encoding
+-- discards informaiton, so encode followed by decode is not the
+-- identity.
+char8 :: TextEncoding
+char8 = Latin1.latin1
+
-- | Look up the named Unicode encoding. May fail with
--
-- * 'isDoesNotExistError' if the encoding is unknown
--
--- The set of known encodings is system-dependent.
+-- The set of known encodings is system-dependent, but includes at least:
+--
+-- * @UTF-8@
+--
+-- * @UTF-16@, @UTF-16BE@, @UTF-16LE@
+--
+-- * @UTF-32@, @UTF-32BE@, @UTF-32LE@
+--
+-- On systems using GNU iconv (e.g. Linux), there is additional
+-- notation for specifying how illegal characters are handled:
+--
+-- * a suffix of @\/\/IGNORE@, e.g. @UTF-8\/\/IGNORE@, will cause
+-- all illegal sequences on input to be ignored, and on output
+-- will drop all code points that have no representation in the
+-- target encoding.
+--
+-- * a suffix of @\/\/TRANSLIT@ will choose a replacement character
+-- for illegal sequences or code points.
+--
+-- On Windows, you can access supported code pages with the prefix
+-- @CP@; for example, @\"CP1250\"@.
--
mkTextEncoding :: String -> IO TextEncoding
-#if !defined(mingw32_HOST_OS)
-mkTextEncoding = Iconv.mkTextEncoding
+mkTextEncoding e = case mb_coding_failure_mode of
+ Nothing -> unknown_encoding
+ Just cfm -> case enc of
+ "UTF-8" -> return $ UTF8.mkUTF8 cfm
+ "UTF-16" -> return $ UTF16.mkUTF16 cfm
+ "UTF-16LE" -> return $ UTF16.mkUTF16le cfm
+ "UTF-16BE" -> return $ UTF16.mkUTF16be cfm
+ "UTF-32" -> return $ UTF32.mkUTF32 cfm
+ "UTF-32LE" -> return $ UTF32.mkUTF32le cfm
+ "UTF-32BE" -> return $ UTF32.mkUTF32be cfm
+#if defined(mingw32_HOST_OS)
+ 'C':'P':n | [(cp,"")] <- reads n -> return $ CodePage.mkCodePageEncoding cfm cp
+ _ -> unknown_encoding
#else
-mkTextEncoding "UTF-8" = return utf8
-mkTextEncoding "UTF-16" = return utf16
-mkTextEncoding "UTF-16LE" = return utf16le
-mkTextEncoding "UTF-16BE" = return utf16be
-mkTextEncoding "UTF-32" = return utf32
-mkTextEncoding "UTF-32LE" = return utf32le
-mkTextEncoding "UTF-32BE" = return utf32be
-mkTextEncoding e = ioException
- (IOError Nothing NoSuchThing "mkTextEncoding"
- ("unknown encoding:" ++ e) Nothing Nothing)
+ _ -> Iconv.mkIconvEncoding cfm enc
#endif
+ where
+ -- The only problem with actually documenting //IGNORE and //TRANSLIT as
+ -- supported suffixes is that they are not necessarily supported with non-GNU iconv
+ (enc, suffix) = span (/= '/') e
+ mb_coding_failure_mode = case suffix of
+ "" -> Just ErrorOnCodingFailure
+ "//IGNORE" -> Just IgnoreCodingFailure
+ "//TRANSLIT" -> Just TransliterateCodingFailure
+ "//ROUNDTRIP" -> Just RoundtripFailure
+ _ -> Nothing
+
+ unknown_encoding = ioException (IOError Nothing NoSuchThing "mkTextEncoding"
+ ("unknown encoding:" ++ e) Nothing Nothing)
latin1_encode :: CharBuffer -> Buffer Word8 -> IO (CharBuffer, Buffer Word8)
-latin1_encode = Latin1.latin1_encode -- unchecked, used for binary
+latin1_encode input output = fmap (\(_why,input',output') -> (input',output')) $ Latin1.latin1_encode input output -- unchecked, used for char8
--latin1_encode = unsafePerformIO $ do mkTextEncoder Iconv.latin1 >>= return.encode
latin1_decode :: Buffer Word8 -> CharBuffer -> IO (Buffer Word8, CharBuffer)
-latin1_decode = Latin1.latin1_decode
+latin1_decode input output = fmap (\(_why,input',output') -> (input',output')) $ Latin1.latin1_decode input output
--latin1_decode = unsafePerformIO $ do mkTextDecoder Iconv.latin1 >>= return.encode
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