141 lines
6.0 KiB
C++
141 lines
6.0 KiB
C++
/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#ifndef nsIUnicodeDecoder_h___
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#define nsIUnicodeDecoder_h___
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#include "nscore.h"
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#include "nsISupports.h"
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// Interface ID for our Unicode Decoder interface
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// {25359602-FC70-4d13-A9AB-8086D3827C0D}
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//NS_DECLARE_ID(kIUnicodeDecoderIID,
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// 0x25359602, 0xfc70, 0x4d13, 0xa9, 0xab, 0x80, 0x86, 0xd3, 0x82, 0x7c, 0xd);
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#define NS_IUNICODEDECODER_IID \
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{ 0x25359602, 0xfc70, 0x4d13, \
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{ 0xa9, 0xab, 0x80, 0x86, 0xd3, 0x82, 0x7c, 0xd }}
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#define NS_UNICODEDECODER_CONTRACTID_BASE "@mozilla.org/intl/unicode/decoder;1?charset="
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/**
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* Interface for a Converter from a Charset into Unicode.
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*
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* @created 23/Nov/1998
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* @author Catalin Rotaru [CATA]
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*/
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class nsIUnicodeDecoder : public nsISupports
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{
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public:
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NS_DECLARE_STATIC_IID_ACCESSOR(NS_IUNICODEDECODER_IID)
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enum {
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kOnError_Recover, // on an error, recover and continue
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kOnError_Signal // on an error, stop and signal
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};
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/**
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* Converts the data from one Charset to Unicode.
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*
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* About the byte ordering:
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* - For input, if the converter cares (that depends of the charset, for
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* example a singlebyte will ignore the byte ordering) it should assume
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* network order. If necessary and requested, we can add a method
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* SetInputByteOrder() so that the reverse order can be used, too. That
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* method would have as default the assumed network order.
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* - The output stream is Unicode, having the byte order which is internal
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* for the machine on which the converter is running on.
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*
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* Unless there is not enough output space, this method must consume all the
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* available input data! The eventual incomplete final character data will be
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* stored internally in the converter and used when the method is called
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* again for continuing the conversion. This way, the caller will not have to
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* worry about managing incomplete input data by mergeing it with the next
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* buffer.
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*
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* Error conditions:
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* If the read value does not belong to this character set, one should
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* replace it with the Unicode special 0xFFFD. When an actual input error is
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* encountered, like a format error, the converter stop and return error.
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* However, we should keep in mind that we need to be lax in decoding. When
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* a decoding error is returned to the caller, it is the caller's
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* responsibility to advance over the bad byte (unless aSrcLength is -1 in
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* which case the caller should call the decoder with 0 offset again) and
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* reset the decoder before trying to call the decoder again.
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*
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* Converter required behavior:
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* In this order: when output space is full - return right away. When input
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* data is wrong, return input pointer right after the wrong byte. When
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* partial input, it will be consumed and cached. All the time input pointer
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* will show how much was actually consumed and how much was actually
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* written.
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*
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* @param aSrc [IN] the source data buffer
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* @param aSrcLength [IN/OUT] the length of source data buffer; after
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* conversion will contain the number of bytes read or
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* -1 on error to indicate that the caller should re-push
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* the same buffer after resetting the decoder
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* @param aDest [OUT] the destination data buffer
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* @param aDestLength [IN/OUT] the length of the destination data buffer;
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* after conversion will contain the number of Unicode
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* characters written
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* @return NS_ERROR_UDEC_ILLEGALINPUT if an illegal input sequence
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* was encountered and the behavior was set to "signal";
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* the caller must skip over one byte, reset the decoder
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* and retry.
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* NS_OK_UDEC_MOREOUTPUT if only a partial conversion
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* was done; more output space is needed to continue
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* NS_OK_UDEC_MOREINPUT if the input ended in the middle
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* of an input code unit sequence. If this is the last
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* result the caller has at the end of the stream, the
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* caller must append one U+FFFD to the output.
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* NS_OK if the input ended after a complete input code
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* unit sequence.
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*/
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NS_IMETHOD Convert(const char * aSrc, int32_t * aSrcLength,
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char16_t * aDest, int32_t * aDestLength) = 0;
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/**
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* Returns a quick estimation of the size of the buffer needed to hold the
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* converted data. Remember: this estimation is >= with the actual size of
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* the buffer needed. It will be computed for the "worst case"
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*
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* @param aSrc [IN] the source data buffer
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* @param aSrcLength [IN] the length of source data buffer
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* @param aDestLength [OUT] the needed size of the destination buffer
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* @return NS_EXACT_LENGTH if an exact length was computed
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* NS_ERROR_OUT_OF_MEMORY if OOM
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* NS_OK is all we have is an approximation
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*/
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MOZ_MUST_USE NS_IMETHOD GetMaxLength(const char* aSrc,
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int32_t aSrcLength,
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int32_t* aDestLength) = 0;
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/**
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* Resets the charset converter so it may be recycled for a completely
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* different and urelated buffer of data.
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*/
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NS_IMETHOD Reset() = 0;
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/**
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* Specify what to do when a character cannot be mapped into unicode
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*
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* @param aBehavior [IN] the desired behavior
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* @see kOnError_Recover
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* @see kOnError_Signal
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*/
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virtual void SetInputErrorBehavior(int32_t aBehavior) = 0;
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/**
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* return the UNICODE character for unmapped character
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*/
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virtual char16_t GetCharacterForUnMapped() = 0;
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};
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NS_DEFINE_STATIC_IID_ACCESSOR(nsIUnicodeDecoder, NS_IUNICODEDECODER_IID)
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#endif /* nsIUnicodeDecoder_h___ */
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