Movatterモバイル変換

{-# LANGUAGE Trustworthy #-}{-# LANGUAGE NoImplicitPrelude, ExistentialQuantification #-}{-# OPTIONS_GHC -funbox-strict-fields #-}------------------------------------------------------------------------------- |-- Module      :  GHC.IO.Encoding.Types-- Copyright   :  (c) The University of Glasgow, 2008-2009-- License     :  see libraries/base/LICENSE---- Maintainer  :  libraries@haskell.org-- Stability   :  internal-- Portability :  non-portable---- Types for text encoding/decoding-------------------------------------------------------------------------------moduleGHC.IO.Encoding.Types(BufferCodec(..),TextEncoding(..),TextEncoder,TextDecoder,CodeBuffer,EncodeBuffer,DecodeBuffer,CodingProgress(..))whereimportGHC.BaseimportGHC.WordimportGHC.Show-- import GHC.IOimportGHC.IO.Buffer-- ------------------------------------------------------------------------------- Text encoders/decodersdataBufferCodecfromtostate=BufferCodec{BufferCodec from to state -> CodeBuffer from toencode::CodeBufferfromto,-- ^ The @encode@ function translates elements of the buffer @from@-- to the buffer @to@.  It should translate as many elements as possible-- given the sizes of the buffers, including translating zero elements-- if there is either not enough room in @to@, or @from@ does not-- contain a complete multibyte sequence.---- If multiple CodingProgress returns are possible, OutputUnderflow must be-- preferred to InvalidSequence. This allows GHC's IO library to assume that-- if we observe InvalidSequence there is at least a single element available-- in the output buffer.---- The fact that as many elements as possible are translated is used by the IO-- library in order to report translation errors at the point they-- actually occur, rather than when the buffer is translated.BufferCodec from to state-> Buffer from -> Buffer to -> IO (Buffer from, Buffer to)recover::Bufferfrom->Bufferto->IO(Bufferfrom,Bufferto),-- ^ The @recover@ function is used to continue decoding-- in the presence of invalid or unrepresentable sequences. This includes-- both those detected by @encode@ returning @InvalidSequence@ and those-- that occur because the input byte sequence appears to be truncated.---- Progress will usually be made by skipping the first element of the @from@-- buffer. This function should only be called if you are certain that you-- wish to do this skipping and if the @to@ buffer has at least one element-- of free space. Because this function deals with decoding failure, it assumes-- that the from buffer has at least one element.---- @recover@ may raise an exception rather than skipping anything.---- Currently, some implementations of @recover@ may mutate the input buffer.-- In particular, this feature is used to implement transliteration.---- @since 4.4.0.0BufferCodec from to state -> IO ()close::IO(),-- ^ Resources associated with the encoding may now be released.-- The @encode@ function may not be called again after calling-- @close@.BufferCodec from to state -> IO stategetState::IOstate,-- ^ Return the current state of the codec.---- Many codecs are not stateful, and in these case the state can be-- represented as '()'.  Other codecs maintain a state.  For-- example, UTF-16 recognises a BOM (byte-order-mark) character at-- the beginning of the input, and remembers thereafter whether to-- use big-endian or little-endian mode.  In this case, the state-- of the codec would include two pieces of information: whether we-- are at the beginning of the stream (the BOM only occurs at the-- beginning), and if not, whether to use the big or little-endian-- encoding.BufferCodec from to state -> state -> IO ()setState::state->IO()-- restore the state of the codec using the state from a previous-- call to 'getState'.}typeCodeBufferfromto=Bufferfrom->Bufferto->IO(CodingProgress,Bufferfrom,Bufferto)typeDecodeBuffer=CodeBufferWord8ChartypeEncodeBuffer=CodeBufferCharWord8typeTextDecoderstate=BufferCodecWord8CharBufElemstatetypeTextEncoderstate=BufferCodecCharBufElemWord8state-- | A 'TextEncoding' is a specification of a conversion scheme-- between sequences of bytes and sequences of Unicode characters.---- For example, UTF-8 is an encoding of Unicode characters into a sequence-- of bytes.  The 'TextEncoding' for UTF-8 is 'System.IO.utf8'.dataTextEncoding=foralldstateestate.TextEncoding{TextEncoding -> StringtextEncodingName::String,-- ^ a string that can be passed to 'System.IO.mkTextEncoding' to-- create an equivalent 'TextEncoding'.()mkTextDecoder::IO(TextDecoderdstate),-- ^ Creates a means of decoding bytes into characters: the result must not-- be shared between several byte sequences or simultaneously across threads()mkTextEncoder::IO(TextEncoderestate)-- ^ Creates a means of encode characters into bytes: the result must not-- be shared between several character sequences or simultaneously across threads}-- | @since 4.3.0.0instanceShowTextEncodingwhere-- | Returns the value of 'textEncodingName'show :: TextEncoding -> StringshowTextEncodingte=TextEncoding -> StringtextEncodingNameTextEncodingte-- | @since 4.4.0.0dataCodingProgress=InputUnderflow-- ^ Stopped because the input contains insufficient available elements,-- or all of the input sequence has been successfully translated.|OutputUnderflow-- ^ Stopped because the output contains insufficient free elements|InvalidSequence-- ^ Stopped because there are sufficient free elements in the output-- to output at least one encoded ASCII character, but the input contains-- an invalid or unrepresentable sequencederiving(Eq-- ^ @since 4.4.0.0,Show-- ^ @since 4.4.0.0)