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#ifndef __PNG_Support_hpp__
#define __PNG_Support_hpp__ 1
// =================================================================================================
// Copyright Adobe
// Copyright 2007 Adobe
// All Rights Reserved
//
// NOTICE: Adobe permits you to use, modify, and distribute this file in accordance with the terms
// of the Adobe license agreement accompanying it.
// =================================================================================================
#include "public/include/XMP_Environment.h" // ! XMP_Environment.h must be the first included header.
#include "public/include/XMP_Const.h"
#include "public/include/XMP_IO.hpp"
#include "XMPFiles/source/XMPFiles_Impl.hpp"
#include "source/XMPFiles_IO.hpp"
#define PNG_SIGNATURE_LEN 8
#define PNG_SIGNATURE_DATA "\x89\x50\x4E\x47\x0D\x0A\x1A\x0A"
#define ITXT_CHUNK_TYPE "iTXt"
#define ITXT_HEADER_LEN 22
#define ITXT_HEADER_DATA "XML:com.adobe.xmp\0\0\0\0\0"
namespace PNG_Support
{
class ChunkData
{
public:
ChunkData() : pos(0), len(0), type(0), xmp(false) {}
virtual ~ChunkData() {}
// | length | type | data | crc(type+data) |
// | 4 | 4 | val(length) | 4 |
//
XMP_Uns64 pos; // file offset of chunk
XMP_Uns32 len; // length of chunk data
long type; // name/type of chunk
bool xmp; // iTXt-chunk with XMP ?
};
typedef std::vector<ChunkData> ChunkVector;
typedef ChunkVector::iterator ChunkIterator;
class ChunkState
{
public:
ChunkState() : xmpPos(0), xmpLen(0) {}
virtual ~ChunkState() {}
XMP_Uns64 xmpPos;
XMP_Uns32 xmpLen;
ChunkData xmpChunk;
ChunkVector chunks; /* vector of chunks */
};
long OpenPNG ( XMP_IO* fileRef, ChunkState& inOutChunkState );
bool ReadChunk ( XMP_IO* fileRef, ChunkState& inOutChunkState, long* chunkType, XMP_Uns32* chunkLength, XMP_Int64& inOutPosition );
bool WriteXMPChunk ( XMP_IO* fileRef, XMP_Uns32 len, const char* inBuffer );
bool CopyChunk ( XMP_IO* sourceRef, XMP_IO* destRef, ChunkData& chunk );
unsigned long UpdateChunkCRC( XMP_IO* fileRef, ChunkData& inOutChunkData );
bool CheckIHDRChunkHeader ( ChunkData& inOutChunkData );
unsigned long CheckiTXtChunkHeader ( XMP_IO* fileRef, ChunkState& inOutChunkState, ChunkData& inOutChunkData );
bool ReadBuffer ( XMP_IO* fileRef, XMP_Uns64& pos, XMP_Uns32 len, char* outBuffer );
bool WriteBuffer ( XMP_IO* fileRef, XMP_Uns64& pos, XMP_Uns32 len, const char* inBuffer );
unsigned long CalculateCRC( unsigned char* inBuffer, XMP_Uns32 len );
//These 2 functions are introduced to reduce the file read call which is required to find
//and process XMP in PNG file. Reading small data from file is an expensive operation
//if processed file is present on network.
//Instead of reading 8 bytes to identify each chunk type(see ReadChunk), FindAndReadXMPChunk will copy the file data in a buffer of 1 MB and then process it.
//see bug CTECHXMP-4169872.
//Now PNG_MetaHandler::CacheFileData is using this function instead of OpenPNG.
bool FindAndReadXMPChunk ( XMP_IO* fileRef, std::string& outXMPPacket,XMP_Int64& xmpOffset, bool isOpenForRead );
bool ExtractXMPPacket(XMP_IO* fileRef, XMP_Uns32 chunkLength, XMP_Uns8* buffer, XMP_Int64 bytesInBuffer,XMP_Int64 filePosition, std::string& outXMPPacket,XMP_Int64& xmpOffset);
} // namespace PNG_Support
#endif // __PNG_Support_hpp__
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