C++ dng_stream::Position方法代码示例

dng_opcode_GainMap::dng_opcode_GainMap (dng_host &host,
										dng_stream &stream)
												
	:	dng_inplace_opcode (dngOpcode_GainMap,
							stream,
							"GainMap")
							
	,	fAreaSpec ()
							
	,	fGainMap ()
							
	{
	
	uint32 byteCount = stream.Get_uint32 ();
	
	uint64 startPosition = stream.Position ();
	
	fAreaSpec.GetData (stream);
	
	fGainMap.Reset (dng_gain_map::GetStream (host, stream));
	
	if (stream.Position () != startPosition + byteCount)
		{
		ThrowBadFormat ();
		}
		
	}

void dng_jpeg_preview::WriteData (dng_host & /* host */,
								  dng_image_writer & /* writer */,
								  dng_basic_tag_set &basic,
								  dng_stream &stream) const
	{
	
	basic.SetTileOffset (0, (uint32) stream.Position ());
	
	basic.SetTileByteCount (0, fCompressedData->LogicalSize ());
	
	stream.Put (fCompressedData->Buffer      (),
				fCompressedData->LogicalSize ());

	if (fCompressedData->LogicalSize () & 1)
		{
		stream.Put_uint8 (0);
		}
			
	}

void dng_info::Parse (dng_host &host,
					  dng_stream &stream)
	{
	
	fTIFFBlockOffset = stream.Position ();
	
	fTIFFBlockOriginalOffset = stream.PositionInOriginalFile ();
	
	// Check byte order indicator.
	
	uint16 byteOrder = stream.Get_uint16 ();
	
	if (byteOrder == byteOrderII)
		{
		
		fBigEndian = false;
		
		#if qDNGValidate
		
		if (gVerbose)
			{
			printf ("\nUses little-endian byte order\n");
			}
			
		#endif
			
		stream.SetLittleEndian ();
		
		}
		
	else if (byteOrder == byteOrderMM)
		{

		fBigEndian = true;
		
		#if qDNGValidate
		
		if (gVerbose)
			{
			printf ("\nUses big-endian byte order\n");
			}
			
		#endif
			
		stream.SetBigEndian ();
		
		}
		
	else
		{
		
		#if qDNGValidate
		
		ReportError ("Unknown byte order");
					 
		#endif
					 
		ThrowBadFormat ();

		}
		
	// Check "magic number" indicator.
		
	fMagic = stream.Get_uint16 ();
	
	#if qDNGValidate
	
	if (gVerbose)
		{
		printf ("Magic number = %u\n\n", (unsigned) fMagic);
		}
		
	#endif
	
	ValidateMagic ();
	
	// Parse IFD 0.
	
	uint64 next_offset = stream.Get_uint32 ();
	
	fExif.Reset (host.Make_dng_exif ());
	
	fShared.Reset (host.Make_dng_shared ());
	
	fIFD [0].Reset (host.Make_dng_ifd ());
	
	ParseIFD (host,
			  stream,
			  fExif.Get (),
			  fShared.Get (),
			  fIFD [0].Get (),
			  fTIFFBlockOffset + next_offset,
			  fTIFFBlockOffset,
			  0);
			  	
	next_offset = fIFD [0]->fNextIFD;
	
	fIFDCount = 1;
	
	// Parse chained IFDs.
//.........这里部分代码省略.........

void dng_info::ParseDNGPrivateData (dng_host &host,
									dng_stream &stream)
	{
	
	if (fShared->fDNGPrivateDataCount < 2)
		{
		return;
		}
	
	// DNG private data should always start with a null-terminated 
	// company name, to define the format of the private data.
			
	dng_string privateName;
			
		{
			
		char buffer [64];
		
		stream.SetReadPosition (fShared->fDNGPrivateDataOffset);
	
		uint32 readLength = Min_uint32 (fShared->fDNGPrivateDataCount,
										sizeof (buffer) - 1);
		
		stream.Get (buffer, readLength);
		
		buffer [readLength] = 0;
		
		privateName.Set (buffer);
		
		}
		
	// Pentax is storing their MakerNote in the DNGPrivateData data.
	
	if (privateName.StartsWith ("PENTAX" ) ||
		privateName.StartsWith ("SAMSUNG"))
		{
		
		#if qDNGValidate
		
		if (gVerbose)
			{
			printf ("Parsing Pentax/Samsung DNGPrivateData\n\n");
			}
			
		#endif

		stream.SetReadPosition (fShared->fDNGPrivateDataOffset + 8);
		
		bool bigEndian = stream.BigEndian ();
		
		uint16 endianMark = stream.Get_uint16 ();
		
		if (endianMark == byteOrderMM)
			{
			bigEndian = true;
			}
			
		else if (endianMark == byteOrderII)
			{
			bigEndian = false;
			}
			
		TempBigEndian temp_endian (stream, bigEndian);
	
		ParseMakerNoteIFD (host,
						   stream,
						   fShared->fDNGPrivateDataCount - 10,
						   fShared->fDNGPrivateDataOffset + 10,
						   fShared->fDNGPrivateDataOffset,
						   fShared->fDNGPrivateDataOffset,
						   fShared->fDNGPrivateDataOffset + fShared->fDNGPrivateDataCount,
						   tcPentaxMakerNote);
						   
		return;
		
		}
				
	// Stop parsing if this is not an Adobe format block.
	
	if (!privateName.Matches ("Adobe"))
		{
		return;
		}
	
	TempBigEndian temp_order (stream);
	
	uint32 section_offset = 6;
	
	while (section_offset + 8 < fShared->fDNGPrivateDataCount)
		{
		
		stream.SetReadPosition (fShared->fDNGPrivateDataOffset + section_offset);
		
		uint32 section_key   = stream.Get_uint32 ();
		uint32 section_count = stream.Get_uint32 ();
		
		if (section_key == DNG_CHAR4 ('M','a','k','N') && section_count > 6)
			{
			
			#if qDNGValidate
//.........这里部分代码省略.........

bool dng_camera_profile_info::ParseExtended (dng_stream &stream)
	{

	try
		{

		// Offsets are relative to the start of this structure, not the entire file.

		uint64 startPosition = stream.Position ();

		// Read header. Like a TIFF header, but with different magic number
		// Plus all offsets are relative to the start of the IFD, not to the
		// stream or file.

		uint16 byteOrder = stream.Get_uint16 ();

		if (byteOrder == byteOrderMM)
			fBigEndian = true;

		else if (byteOrder == byteOrderII)
			fBigEndian = false;

		else
			return false;

		TempBigEndian setEndianness (stream, fBigEndian);

		uint16 magicNumber = stream.Get_uint16 ();

		if (magicNumber != magicExtendedProfile)
			{
			return false;
			}

		uint32 offset = stream.Get_uint32 ();

		stream.Skip (offset - 8);

		// Start on IFD entries.

		uint32 ifdEntries = stream.Get_uint16 ();

		if (ifdEntries < 1)
			{
			return false;
			}

		for (uint32 tag_index = 0; tag_index < ifdEntries; tag_index++)
			{

			stream.SetReadPosition (startPosition + 8 + 2 + tag_index * 12);

			uint16 tagCode  = stream.Get_uint16 ();
			uint32 tagType  = stream.Get_uint16 ();
			uint32 tagCount = stream.Get_uint32 ();

			uint64 tagOffset = stream.Position ();

			if (TagTypeSize (tagType) * tagCount > 4)
				{

				tagOffset = startPosition + stream.Get_uint32 ();

				stream.SetReadPosition (tagOffset);

				}

			if (!ParseTag (stream,
						   0,
						   tagCode,
						   tagType,
						   tagCount,
						   tagOffset))
				{

				#if qDNGValidate

				if (gVerbose)
					{

					stream.SetReadPosition (tagOffset);

					printf ("*");

					DumpTagValues (stream,
								   LookupTagType (tagType),
								   0,
								   tagCode,
								   tagType,
								   tagCount);

					}

				#endif

				}

			}

		return true;
//.........这里部分代码省略.........