C++ XMP_IO类代码示例

void TIFF_MetaHandler::WriteTempFile ( XMP_IO* tempRef )
{
	XMP_IO* origRef = this->parent->ioRef;

	XMP_AbortProc abortProc  = this->parent->abortProc;
	void *        abortArg   = this->parent->abortArg;

	XMP_Int64 fileLen = origRef->Length();
	if ( fileLen > 0xFFFFFFFFLL ) {	// Check before making a copy of the file.
		XMP_Throw ( "TIFF fles can't exceed 4GB", kXMPErr_BadTIFF );
	}
	
	XMP_ProgressTracker* progressTracker = this->parent->progressTracker;
	if ( progressTracker != 0 ) progressTracker->BeginWork ( (float)fileLen );

	origRef->Rewind ( );
	tempRef->Truncate ( 0 );
	XIO::Copy ( origRef, tempRef, fileLen, abortProc, abortArg );

	try {
		this->parent->ioRef = tempRef;	// ! Make UpdateFile update the temp.
		this->UpdateFile ( false );
		this->parent->ioRef = origRef;
	} catch ( ... ) {
		this->parent->ioRef = origRef;
		throw;
	}
	
	if ( progressTracker != 0 ) progressTracker->WorkComplete();

}	// TIFF_MetaHandler::WriteTempFile

void GIF_MetaHandler::UpdateFile ( bool doSafeUpdate )
{
	IgnoreParam(doSafeUpdate);
	XMP_Assert( !doSafeUpdate );	// This should only be called for "unsafe" updates.

	if ( ! this->needsUpdate ) return;

	XMP_IO * fileRef = this->parent->ioRef;

	/*XMP_StringPtr packetStr = xmpPacket.c_str();*/
	XMP_StringLen newPacketLength = (XMP_StringLen)xmpPacket.size();

	if ( newPacketLength == XMPPacketLength )
	{
		this->SeekFile( fileRef, this->packetInfo.offset, kXMP_SeekFromStart );
		fileRef->Write( this->xmpPacket.c_str(), newPacketLength );
	}
	else
	{
		XMP_IO* tempFile = fileRef->DeriveTemp();
		if ( tempFile == 0 ) XMP_Throw( "Failure creating GIF temp file", kXMPErr_InternalFailure );

		this->WriteTempFile( tempFile );
		fileRef->AbsorbTemp();
	}

	this->needsUpdate = false;

}	// GIF_MetaHandler::UpdateFile

void RIFF_MetaHandler::CacheFileData()
{
	this->containsXMP = false; //assume for now

	XMP_IO* file = this->parent->ioRef;
	this->oldFileSize = file ->Length();
	if ( (this->parent->format == kXMP_WAVFile) && (this->oldFileSize > 0xFFFFFFFF) )
		XMP_Throw ( "RIFF_MetaHandler::CacheFileData: WAV Files larger 4GB not supported", kXMPErr_Unimplemented );

	file ->Rewind();
	this->level = 0;

	// parse top-level chunks (most likely just one, except large avi files)
	XMP_Int64 filePos = 0;
	while ( filePos < this->oldFileSize )
	{

		this->riffChunks.push_back( (RIFF::ContainerChunk*) RIFF::getChunk( NULL, this ) );

		// Tolerate limited forms of trailing garbage in a file. Some apps append private data.

		filePos = file->Offset();
		XMP_Int64 fileTail = this->oldFileSize - filePos;

		if ( fileTail != 0 ) {

			if ( fileTail < 12 ) {

				this->oldFileSize = filePos;	// Pretend the file is smaller.
				this->trailingGarbageSize = fileTail;

			} else if ( this->parent->format == kXMP_WAVFile ) {

				if ( fileTail < 1024*1024 ) {
					this->oldFileSize = filePos;	// Pretend the file is smaller.
					this->trailingGarbageSize = fileTail;
				} else {
					XMP_Throw ( "Excessive garbage at end of file", kXMPErr_BadFileFormat )
				}

			} else {

				XMP_Int32 chunkInfo [3];
				file->ReadAll ( &chunkInfo, 12 );
				file->Seek ( -12, kXMP_SeekFromCurrent );
				if ( (GetUns32LE ( &chunkInfo[0] ) != RIFF::kChunk_RIFF) || (GetUns32LE ( &chunkInfo[2] ) != RIFF::kType_AVIX) ) {
					if ( fileTail < 1024*1024 ) {
						this->oldFileSize = filePos;	// Pretend the file is smaller.
						this->trailingGarbageSize = fileTail;
					} else {
						XMP_Throw ( "Excessive garbage at end of file", kXMPErr_BadFileFormat )
					}
				}

			}

		}

	}

bool ASF_MetaHandler::SafeWriteFile()
{
	XMP_IO* originalFile = this->parent->ioRef;
	XMP_IO* tempFile = originalFile->DeriveTemp();
	if ( tempFile == 0 ) XMP_Throw ( "Failure creating ASF temp file", kXMPErr_InternalFailure );

	this->WriteTempFile ( tempFile );
	originalFile->AbsorbTemp();

	return true;

} // ASF_MetaHandler::SafeWriteFile

void Trivial_MetaHandler::UpdateFile ( bool doSafeUpdate )
{
	IgnoreParam ( doSafeUpdate );
	XMP_Assert ( ! doSafeUpdate );	// Not supported at this level.
	if ( ! this->needsUpdate ) return;

	XMP_IO*      fileRef    = this->parent->ioRef;
	XMP_PacketInfo & packetInfo = this->packetInfo;
	std::string &    xmpPacket  = this->xmpPacket;

	fileRef->Seek ( packetInfo.offset, kXMP_SeekFromStart );
	fileRef->Write ( xmpPacket.c_str(), packetInfo.length );
	XMP_Assert ( xmpPacket.size() == (size_t)packetInfo.length );

	this->needsUpdate = false;

}	// Trivial_MetaHandler::UpdateFile

// b) parse
XMPChunk::XMPChunk( ContainerChunk* parent_, RIFF_MetaHandler* handler ) : Chunk( parent_, handler, false, chunk_XMP )
{
	chunkType = chunk_XMP;
	XMP_IO* file = handler->parent->ioRef;
	/*XMP_Uns8 level = handler->level*/;

	handler->packetInfo.offset = this->oldPos + 8;
	handler->packetInfo.length = (XMP_Int32) this->oldSize - 8;

	handler->xmpPacket.reserve ( handler->packetInfo.length );
	handler->xmpPacket.assign ( handler->packetInfo.length, ' ' );
	file->ReadAll ( (void*)handler->xmpPacket.data(), handler->packetInfo.length );

	handler->containsXMP = true; // last, after all possible failure

	// pointer for later processing
	handler->xmpChunk = this;
}

void GIF_MetaHandler::WriteTempFile ( XMP_IO* tempRef )
{
	XMP_Assert( this->needsUpdate );

	XMP_IO* originalRef = this->parent->ioRef;
	originalRef->Rewind();

	tempRef->Truncate ( 0 );
	
	if ( XMPPacketOffset != 0 )
	{
		// Copying blocks before XMP Application Block
		XIO::Copy( originalRef, tempRef, XMPPacketOffset );

		// Writing XMP Packet
		tempRef->Write( this->xmpPacket.c_str(), (XMP_Uns32)this->xmpPacket.size() );

		// Copying Rest of the file
		originalRef->Seek( XMPPacketLength, kXMP_SeekFromCurrent );
		XIO::Copy( originalRef, tempRef, originalRef->Length() - originalRef->Offset() );

	}
	else
	{
		if ( trailerOffset == 0 )
			XMP_Throw( "Not able to write XMP packet in GIF file", kXMPErr_BadFileFormat );

		// Copying blocks before XMP Application Block
		XIO::Copy( originalRef, tempRef, trailerOffset );

		// Writing Extension Introducer 
		XIO::WriteUns8( tempRef, kXMP_block_Extension );

		// Writing Application Extension label
		XIO::WriteUns8( tempRef, 0xFF );

		// Writing Application Extension label
		XIO::WriteUns8( tempRef, APP_ID_LEN );

		// Writing Application Extension label
		tempRef->Write( XMP_APP_ID_DATA, APP_ID_LEN );

		// Writing XMP Packet
		tempRef->Write( this->xmpPacket.c_str(), (XMP_Uns32)this->xmpPacket.size() );

		// Writing Magic trailer
		XMP_Uns8 magicByte = 0x01;
		tempRef->Write( &magicByte, 1 );
		for ( magicByte = 0xFF; magicByte != 0x00; --magicByte )
			tempRef->Write( &magicByte, 1 );
		tempRef->Write( &magicByte, 1 );
		tempRef->Write( &magicByte, 1 );

		// Copying Rest of the file
		XIO::Copy( originalRef, tempRef, originalRef->Length() - originalRef->Offset() );

	}

}	// GIF_MetaHandler::WriteTempFile

void Matroska_MetaHandler::WriteTempFile(XMP_IO* tempRef)
{
    XMP_Assert(needsUpdate);

    XMP_IO* originalRef = parent->ioRef;
    
    bool localProgressTracking(false);
    XMP_ProgressTracker* progressTracker = parent->progressTracker;
    if (progressTracker)
    {
        float xmpSize = static_cast<float>(xmpPacket.size());
        if (progressTracker->WorkInProgress())
        {
            progressTracker->AddTotalWork(xmpSize);
        }
        else
        {
            localProgressTracking = true;
            progressTracker->BeginWork(xmpSize);
        }
    }

    XMP_Assert(tempRef);
    XMP_Assert(originalRef);

    tempRef->Rewind();
    originalRef->Rewind();
    XIO::Copy(originalRef, tempRef, originalRef->Length(), parent->abortProc, parent->abortArg);

    try
    {
        parent->ioRef = tempRef;	// ! Fool UpdateFile into using the temp file.
        UpdateFile(false);
        parent->ioRef = originalRef;
    }
    catch (...)
    {
        parent->ioRef = originalRef;
        throw;
    }
    if (localProgressTracking) progressTracker->WorkComplete();
}

// parsing creation
Chunk::Chunk( ContainerChunk* parent_, RIFF_MetaHandler* handler, bool skip, ChunkType c )
{
	chunkType = c; // base class assumption
	this->parent = parent_;
	this->oldSize = 0;
	this->hasChange = false; // [2414649] valid assumption at creation time

	XMP_IO* file = handler->parent->ioRef;

	this->oldPos = file->Offset();
	this->id = XIO::ReadUns32_LE( file );
	this->oldSize = XIO::ReadUns32_LE( file );
	this->oldSize += 8;

	// Make sure the size is within expected bounds.
	XMP_Int64 chunkEnd = this->oldPos + this->oldSize;
	XMP_Int64 chunkLimit = handler->oldFileSize;
	if ( parent_ != 0 ) chunkLimit = parent_->oldPos + parent_->oldSize;
	if ( chunkEnd > chunkLimit ) {
		bool isUpdate = XMP_OptionIsSet ( handler->parent->openFlags, kXMPFiles_OpenForUpdate );
		bool repairFile = XMP_OptionIsSet ( handler->parent->openFlags, kXMPFiles_OpenRepairFile );
		if ( (! isUpdate) || (repairFile && (parent_ == 0)) ) {
			this->oldSize = chunkLimit - this->oldPos;
		} else {
			XMP_Throw ( "Bad RIFF chunk size", kXMPErr_BadFileFormat );
		}
	}

	this->newSize = this->oldSize;
	this->needSizeFix = false;

	if ( skip ) file->Seek ( (this->oldSize - 8), kXMP_SeekFromCurrent );

	// "good parenting", essential for latter destruction.
	if ( this->parent != NULL )
	{
		this->parent->children.push_back( this );
		if( this->chunkType == chunk_VALUE )
			this->parent->childmap.insert( std::make_pair( this->id, (ValueChunk*) this ) );
	}
}

void GIF_MetaHandler::CacheFileData()
{
	this->containsXMP = false;

	XMP_IO * fileRef = this->parent->ioRef;

	// Try to navigate through the blocks to find the XMP block.
	if ( this->ParseGIFBlocks( fileRef ) )
	{
		// XMP packet present
		this->xmpPacket.assign( XMPPacketLength, ' ' );

		// 13 bytes for the block size and 2 bytes for Extension ID and Label
		this->SeekFile( fileRef, XMPPacketOffset, kXMP_SeekFromStart );
		fileRef->ReadAll( ( void* )this->xmpPacket.data(), XMPPacketLength );

		this->packetInfo.offset = XMPPacketOffset;
		this->packetInfo.length = XMPPacketLength;
		this->containsXMP = true;
	}
	// else no XMP

}	// GIF_MetaHandler::CacheFileData

void Matroska_MetaHandler::UpdateXMP()
{
    XMP_IO* fileRef = parent->ioRef;

    fileRef->Seek(fileRef->Length(), kXMP_SeekFromStart);

    for (auto segment : _dom->_root->getElementsById(kSegment))
    {
        for (auto tags : segment->getElementsById(kTags))
        {
            for (auto tag : tags->getElementsById(kTag))
            {
                for (auto simple_tag : tag->getElementsById(kSimpleTag))
                {
                    auto tag_name = simple_tag->getElementById(kTagName);
                    if (tag_name->_value.StringValue == "XMP")
                    {
                        auto tag_string = simple_tag->getElementById(kTagString);

                        // we have found valid XMP, and if it's in the very end of file, we can truncate segment
                        if (tag_string->_offset + tag_string->size() == fileRef->Length())
                        {
                            segment->_size._value -= tags->size();

                            fileRef->Truncate(tags->_offset);
                            fileRef->Seek(tags->_offset, kXMP_SeekFromStart);
                        }
                        // otherwise, make old XMP tag Void and create new one from the scratch
                        else
                        {
                            tags->wipe(fileRef);
                        }
                    }
                }
            }
        }
    }
    auto segments = _dom->_root->getElementsById(kSegment);
    auto segment = segments.back();

    auto tag_name = std::make_shared<ebml_element_t>(kTagName, ebml_variant_t("XMP"));
    auto tag_string = std::make_shared<ebml_element_t>(kTagString, ebml_variant_t(xmpPacket));
    auto tag_language = std::make_shared<ebml_element_t>(kTagLanguage, ebml_variant_t("eng"));
    auto tag_default = std::make_shared<ebml_element_t>(kTagDefault, ebml_variant_t(1ULL));
    auto simple_tag = std::make_shared<ebml_element_t>(kSimpleTag, ebml_element_t::vec{ tag_language, tag_default, tag_name, tag_string });
    auto tag = std::make_shared<ebml_element_t>(kTag, simple_tag);
    auto tags = std::make_shared<ebml_element_t>(kTags, tag);

    tags->write(fileRef);

    segment->_size._value += tags->size();
    segment->update_header(fileRef);
}

void FLV_MetaHandler::UpdateFile ( bool doSafeUpdate )
{
	if ( ! this->needsUpdate ) return;
	XMP_Assert ( ! doSafeUpdate );	// This should only be called for "unsafe" updates.

	XMP_AbortProc abortProc  = this->parent->abortProc;
	void *        abortArg   = this->parent->abortArg;
	const bool    checkAbort = (abortProc != 0);

	XMP_IO* fileRef  = this->parent->ioRef;
	XMP_Uns64   fileSize = fileRef->Length();

	// Make sure the XMP has a legacy digest if appropriate.

	if ( ! this->onMetaData.empty() ) {

		std::string newDigest;
		this->MakeLegacyDigest ( &newDigest );
		this->xmpObj.SetStructField ( kXMP_NS_XMP, "NativeDigests",
									  kXMP_NS_XMP, "FLV", newDigest.c_str(), kXMP_DeleteExisting );

		try {
			XMP_StringLen xmpLen = (XMP_StringLen)this->xmpPacket.size();
			this->xmpObj.SerializeToBuffer ( &this->xmpPacket, (kXMP_UseCompactFormat | kXMP_ExactPacketLength), xmpLen );
		} catch ( ... ) {
			this->xmpObj.SerializeToBuffer ( &this->xmpPacket, kXMP_UseCompactFormat );
		}

	}

	// Rewrite the packet in-place if it fits. Otherwise rewrite the whole file.

	if ( this->xmpPacket.size() == (size_t)this->packetInfo.length ) {
		XMP_ProgressTracker* progressTracker = this->parent->progressTracker;
		if ( progressTracker != 0 ) progressTracker->BeginWork ( (float)this->xmpPacket.size() );
		fileRef->Seek ( this->packetInfo.offset, kXMP_SeekFromStart );
		fileRef->Write ( this->xmpPacket.data(), (XMP_Int32)this->xmpPacket.size() );
		if ( progressTracker != 0 ) progressTracker->WorkComplete();


	} else {

		XMP_IO* tempRef = fileRef->DeriveTemp();
		if ( tempRef == 0 ) XMP_Throw ( "Failure creating FLV temp file", kXMPErr_InternalFailure );

		this->WriteTempFile ( tempRef );
		fileRef->AbsorbTemp();

	}

	this->needsUpdate = false;

}	// FLV_MetaHandler::UpdateFile

void InDesign_MetaHandler::CacheFileData()
{
	XMP_IO* fileRef = this->parent->ioRef;
	XMP_PacketInfo & packetInfo = this->packetInfo;

	XMP_Assert ( kINDD_PageSize == sizeof(InDesignMasterPage) );
	static const size_t kBufferSize = (2 * kINDD_PageSize);
	XMP_Uns8 buffer [kBufferSize];

	size_t	 dbPages;
	XMP_Uns8 cobjEndian;

	XMP_AbortProc abortProc  = this->parent->abortProc;
	void *        abortArg   = this->parent->abortArg;
	const bool    checkAbort = (abortProc != 0);

	this->containsXMP = false;

	// ---------------------------------------------------------------------------------
	// Figure out which master page is active and seek to the contiguous object portion.

	{
		fileRef->Rewind();
		fileRef->ReadAll ( buffer, (2 * kINDD_PageSize) );

		InDesignMasterPage * masters = (InDesignMasterPage *) &buffer[0];
		XMP_Uns64 seq0 = GetUns64LE ( (XMP_Uns8 *) &masters[0].fSequenceNumber );
		XMP_Uns64 seq1 = GetUns64LE ( (XMP_Uns8 *) &masters[1].fSequenceNumber );

		dbPages = GetUns32LE ( (XMP_Uns8 *) &masters[0].fFilePages );
		cobjEndian = masters[0].fObjectStreamEndian;
		if ( seq1 > seq0 ) {
			dbPages = GetUns32LE ( (XMP_Uns8 *)  &masters[1].fFilePages );
			cobjEndian = masters[1].fObjectStreamEndian;
		}
	}

	XMP_Assert ( ! this->streamBigEndian );
	if ( cobjEndian == kINDD_BigEndian ) this->streamBigEndian = true;

	// ---------------------------------------------------------------------------------------------
	// Look for the XMP contiguous object. Each contiguous object has a header and trailer, both of
	// the InDesignContigObjMarker structure. The stream size in the header/trailer is the number of
	// data bytes between the header and trailer. The XMP stream begins with a 4 byte size of the
	// XMP packet. Yes, this is the contiguous object data size minus 4 - silly but true. The XMP
	// must have a packet wrapper, the leading xpacket PI is used as the marker of XMP.

	XMP_Int64 cobjPos = (XMP_Int64)dbPages * kINDD_PageSize;	// ! Use a 64 bit multiply!
	cobjPos -= (2 * sizeof(InDesignContigObjMarker));			// ! For the first pass in the loop.
	XMP_Uns32 streamLength = 0;									// ! For the first pass in the loop.

	while ( true ) {

		if ( checkAbort && abortProc(abortArg) ) {
			XMP_Throw ( "InDesign_MetaHandler::LocateXMP - User abort", kXMPErr_UserAbort );
		}

		// Fetch the start of the next stream and check the contiguous object header.
		// ! The writeable bit of fObjectClassID is ignored, we use the packet trailer flag.

		cobjPos += streamLength + (2 * sizeof(InDesignContigObjMarker));
		fileRef->Seek ( cobjPos, kXMP_SeekFromStart );
		fileRef->ReadAll ( buffer, sizeof(InDesignContigObjMarker) );

		const InDesignContigObjMarker * cobjHeader = (const InDesignContigObjMarker *) &buffer[0];
		if ( ! CheckBytes ( Uns8Ptr(&cobjHeader->fGUID), kINDDContigObjHeaderGUID, kInDesignGUIDSize ) ) break;	// Not a contiguous object header.
		this->xmpObjID = cobjHeader->fObjectUID;	// Save these now while the buffer is good.
		this->xmpClassID = cobjHeader->fObjectClassID;
		streamLength = GetUns32LE ( (XMP_Uns8 *) &cobjHeader->fStreamLength );

		// See if this is the XMP stream.

		if ( streamLength < (4 + kUTF8_PacketHeaderLen + kUTF8_PacketTrailerLen) ) continue;	// Too small, can't possibly be XMP.

		fileRef->ReadAll ( buffer, (4 + kUTF8_PacketHeaderLen) );
		XMP_Uns32 innerLength = GetUns32LE ( &buffer[0] );
		if ( this->streamBigEndian ) innerLength = GetUns32BE ( &buffer[0] );
		if ( innerLength != (streamLength - 4) ) {
			// Be tolerant of a mistake with the endian flag.
			innerLength = Flip4 ( innerLength );
			if ( innerLength != (streamLength - 4) ) continue;	// Not legit XMP.
		}

		XMP_Uns8 * chPtr = &buffer[4];
		size_t startLen = strlen((char*)kUTF8_PacketStart);
		size_t idLen = strlen((char*)kUTF8_PacketID);
		
		if ( ! CheckBytes ( chPtr, kUTF8_PacketStart, startLen ) ) continue;
		chPtr += startLen;

		XMP_Uns8 quote = *chPtr;
		if ( (quote != '\'') && (quote != '"') ) continue;
		chPtr += 1;
		if ( *chPtr != quote ) {
			if ( ! CheckBytes ( chPtr, Uns8Ptr("\xEF\xBB\xBF"), 3 ) ) continue;
			chPtr += 3;
		}
		if ( *chPtr != quote ) continue;
		chPtr += 1;

//.........这里部分代码省略.........

void TIFF_MetaHandler::UpdateFile ( bool doSafeUpdate )
{
	XMP_Assert ( ! doSafeUpdate );	// This should only be called for "unsafe" updates.

	XMP_IO*   destRef    = this->parent->ioRef;
	XMP_AbortProc abortProc  = this->parent->abortProc;
	void *        abortArg   = this->parent->abortArg;

	XMP_Int64 oldPacketOffset = this->packetInfo.offset;
	XMP_Int32 oldPacketLength = this->packetInfo.length;

	if ( oldPacketOffset == kXMPFiles_UnknownOffset ) oldPacketOffset = 0;	// ! Simplify checks.
	if ( oldPacketLength == kXMPFiles_UnknownLength ) oldPacketLength = 0;

	bool fileHadXMP = ((oldPacketOffset != 0) && (oldPacketLength != 0));

	// Update the IPTC-IIM and native TIFF/Exif metadata. ExportPhotoData also trips the tiff: and
	// exif: copies from the XMP, so reserialize the now final XMP packet.

	ExportPhotoData ( kXMP_TIFFFile, &this->xmpObj, &this->tiffMgr, this->iptcMgr, this->psirMgr );

	try {
		XMP_OptionBits options = kXMP_UseCompactFormat;
		if ( fileHadXMP ) options |= kXMP_ExactPacketLength;
		this->xmpObj.SerializeToBuffer ( &this->xmpPacket, options, oldPacketLength );
	} catch ( ... ) {
		this->xmpObj.SerializeToBuffer ( &this->xmpPacket, kXMP_UseCompactFormat );
	}

	// Decide whether to do an in-place update. This can only happen if all of the following are true:
	//	- There is an XMP packet in the file.
	//	- The are no changes to the legacy tags. (The IPTC and PSIR are in the TIFF tags.)
	//	- The new XMP can fit in the old space.

	bool doInPlace = (fileHadXMP && (this->xmpPacket.size() <= (size_t)oldPacketLength));
	if ( this->tiffMgr.IsLegacyChanged() ) doInPlace = false;
	
	bool localProgressTracking = false;
	XMP_ProgressTracker* progressTracker = this->parent->progressTracker;

	if ( ! doInPlace ) {

		#if GatherPerformanceData
			sAPIPerf->back().extraInfo += ", TIFF append update";
		#endif

		if ( (progressTracker != 0) && (! progressTracker->WorkInProgress()) ) {
			localProgressTracking = true;
			progressTracker->BeginWork();
		}

		this->tiffMgr.SetTag ( kTIFF_PrimaryIFD, kTIFF_XMP, kTIFF_UndefinedType, (XMP_Uns32)this->xmpPacket.size(), this->xmpPacket.c_str() );
		this->tiffMgr.UpdateFileStream ( destRef, progressTracker );

	} else {

		#if GatherPerformanceData
			sAPIPerf->back().extraInfo += ", TIFF in-place update";
		#endif

		if ( this->xmpPacket.size() < (size_t)this->packetInfo.length ) {
			// They ought to match, cheap to be sure.
			size_t extraSpace = (size_t)this->packetInfo.length - this->xmpPacket.size();
			this->xmpPacket.append ( extraSpace, ' ' );
		}

		XMP_IO* liveFile = this->parent->ioRef;

		XMP_Assert ( this->xmpPacket.size() == (size_t)oldPacketLength );	// ! Done by common PutXMP logic.

		if ( progressTracker != 0 ) {
			if ( progressTracker->WorkInProgress() ) {
				progressTracker->AddTotalWork ( this->xmpPacket.size() );
			} else {
				localProgressTracking = true;
				progressTracker->BeginWork ( this->xmpPacket.size() );
			}
		}

		liveFile->Seek ( oldPacketOffset, kXMP_SeekFromStart  );
		liveFile->Write ( this->xmpPacket.c_str(), (XMP_Int32)this->xmpPacket.size() );

	}
	
	if ( localProgressTracking ) progressTracker->WorkComplete();
	this->needsUpdate = false;

}	// TIFF_MetaHandler::UpdateFile

void MP3_MetaHandler::CacheFileData()
{

    //*** abort procedures
    this->containsXMP = false;		//assume no XMP for now

    XMP_IO* file = this->parent->ioRef;
    XMP_PacketInfo &packetInfo = this->packetInfo;

    file->Rewind();

    this->hasID3Tag = this->id3Header.read( file );
    this->majorVersion = this->id3Header.fields[ID3Header::o_vMajor];
    this->minorVersion = this->id3Header.fields[ID3Header::o_vMinor];
    this->hasExtHeader = (0 != ( 0x40 & this->id3Header.fields[ID3Header::o_flags])); //'naturally' false if no ID3Tag
    this->hasFooter = ( 0 != ( 0x10 & this->id3Header.fields[ID3Header::o_flags])); //'naturally' false if no ID3Tag

    // stored size is w/o initial header (thus adding 10)
    // + but extended header (if existing)
    // + padding + frames after unsynchronisation (?)
    // (if no ID3 tag existing, constructed default correctly sets size to 10.)
    this->oldTagSize = ID3Header::kID3_TagHeaderSize + synchToInt32(GetUns32BE( &id3Header.fields[ID3Header::o_size] ));

    if ( ! hasExtHeader ) {

        this->extHeaderSize = 0; // := there is no such header.

    } else {

        this->extHeaderSize = synchToInt32( XIO::ReadInt32_BE( file));
        XMP_Uns8 extHeaderNumFlagBytes = XIO::ReadUns8( file );

        // v2.3 doesn't include the size, while v2.4 does
        if ( this->majorVersion < 4 ) this->extHeaderSize += 4;
        XMP_Validate( this->extHeaderSize >= 6, "extHeader size too small", kXMPErr_BadFileFormat );

        file->Seek ( this->extHeaderSize - 6, kXMP_SeekFromCurrent );

    }

    this->framesVector.clear(); //mac precaution
    ID3v2Frame* curFrame = 0; // reusable

    ////////////////////////////////////////////////////
    // read frames

    XMP_Uns32 xmpID = XMP_V23_ID;
    if ( this->majorVersion == 2 ) xmpID = XMP_V22_ID;

    while ( file->Offset() < this->oldTagSize ) {

        curFrame = new ID3v2Frame();

        try {
            XMP_Int64 frameSize = curFrame->read ( file, this->majorVersion );
            if ( frameSize == 0 ) {
                delete curFrame; // ..since not becoming part of vector for latter delete.
                break;			 // not a throw. There's nothing wrong with padding.
            }
            this->containsXMP = true;
        } catch ( ... ) {
            delete curFrame;
            throw;
        }

        // these are both pointer assignments, no (copy) construction
        // (MemLeak Note: for all things pushed, memory cleanup is taken care of in destructor.)
        this->framesVector.push_back ( curFrame );

        //remember XMP-Frame, if it occurs:
        if ( (curFrame->id ==xmpID) &&
                (curFrame->contentSize > 8) && CheckBytes ( &curFrame->content[0], "XMP\0", 4 ) ) {

            // be sure that this is the first packet (all else would be illegal format)
            XMP_Validate ( this->framesMap[xmpID] == 0, "two XMP packets in one file", kXMPErr_BadFileFormat );
            //add this to map, needed on reconciliation
            this->framesMap[xmpID] = curFrame;

            this->packetInfo.length = curFrame->contentSize - 4; // content minus "XMP\0"
            this->packetInfo.offset = ( file->Offset() - this->packetInfo.length );

            this->xmpPacket.erase(); //safety
            this->xmpPacket.assign( &curFrame->content[4], curFrame->contentSize - 4 );
            this->containsXMP = true; // do this last, after all possible failure

        }

        // No space for another frame? => assume into ID3v2.4 padding.
        XMP_Int64 newPos = file->Offset();
        XMP_Int64 spaceLeft = this->oldTagSize - newPos;	// Depends on first check below!
        if ( (newPos > this->oldTagSize) || (spaceLeft < (XMP_Int64)ID3Header::kID3_TagHeaderSize) ) break;

    }

    ////////////////////////////////////////////////////
    // padding

    this->oldPadding = this->oldTagSize - file->Offset();
    this->oldFramesSize = this->oldTagSize - ID3Header::kID3_TagHeaderSize - this->oldPadding;

//.........这里部分代码省略.........