C++ ZStreamR::Skip方法代码示例

void NPainter_FromPICT(const ZStreamR& inStream, ZDCPixmap& outPixmap)
	{
	inStream.ReadInt16(); // picSize. This field has been obsolete since 1987.
	inStream.ReadInt16(); // picFrame.top
	inStream.ReadInt16(); // picFrame.left
	inStream.ReadInt16(); // picFrame.bottom
	inStream.ReadInt16(); // picFrame.right

	uint8 ch;

	// skip any empty bytes
	while ((ch = inStream.ReadUInt8()) == 0)
		{}

	if (ch != 0x11)
		throw runtime_error("NPainter_FromPICT, expected version opcode");
	if ((ch = inStream.ReadUInt8()) != 0x02)
		throw runtime_error("NPainter_FromPICT, expected version number 2");
	if ((ch = inStream.ReadUInt8()) != 0xFF)
		throw runtime_error("NPainter_FromPICT, expected subcode 0xFF");

	// The order of remaining opcodes is not always the same, hence we use a loop to consume them.
	uint16 opcode;
	while (true)
		{
		opcode = inStream.ReadUInt16();
		if (opcode == 0x0C00) // Header, followed by 24 bytes of data we don't need
			inStream.Skip(24);
		else if (opcode == 0x01) // Clip rgn
			{
			unsigned short clipBytes = inStream.ReadUInt16() - sizeof(short);
			inStream.Skip(clipBytes);
			}
		else if (opcode != 0x1E) // Hilite
			break;
		}
	if (opcode != 0x98)
		throw runtime_error("NPainter_FromPICT, expected packbits opcode");
	// Do the actual read
	::sReadPixmap(inStream, outPixmap);
	// Suck up remaining data
	while ((ch = inStream.ReadUInt8()) == 0x00)
		{}
	if (ch != 0xFF)
		throw runtime_error("NPainter_FromPICT, expected end of picture opcode");
	}

static void sReadRLE8(const ZStreamR& iStream,
	ZCoord iWidth, ZCoord iHeight, size_t iRowBytes, bool iFlip, uint8* iBuffer)
	{
	ZCoord currentRow = 0;
	ZCoord currentCol = 0;
	bool done = false;
	while (!done)
		{
		uint8 count = iStream.ReadUInt8();
		uint8 command = iStream.ReadUInt8();
		if (count == 0)
			{
			switch (command)
				{
				case 0: // Move to start of next row
					{
					currentRow += 1;
					currentCol = 0;
					break;
					}
				case 1: // All done
					{
					done = true;
					break;
					}
				case 2: // Offset by some relative amount
					{
					currentCol += iStream.ReadUInt8();
					currentRow += iStream.ReadUInt8();
					break;
					}
				default: // Absolute data follows -- the length is the value of 'command'
					{
					uint8* destAddress = iBuffer
						+ iRowBytes * (iFlip ? iHeight - currentRow - 1 : currentRow)
						+ currentCol;

					iStream.Read(destAddress, command);
					currentCol += command;
					// An odd number of bytes is followed by a pad byte.
					if ((command & 1) != 0)
						iStream.Skip(1);
					break;
					}
				}
			}
		else
			{
			// Store a run of bytes. The count is in 'count', the value is in 'command'.
			uint8* destAddress = iBuffer
				+ iRowBytes * (iFlip ? iHeight - currentRow - 1 : currentRow) + currentCol;

			for (int x = 0; x < count; ++x)
				*destAddress++ = command;
			currentCol += count;
			}
		}
	}

static bool sTryKF(const ZStreamR& iStream)
	{
	iStream.Skip(8);
	if ('P' != iStream.ReadUInt8() || 'N' != iStream.ReadUInt8() || 'T' != iStream.ReadUInt8() || 'R' != iStream.ReadUInt8())
		{
		return false;
		}
	return true;
	}

void ZStreamW_Null::Internal_CopyFrom(const ZStreamR& iStreamR, uint64 iCount,
	uint64* oCountRead, uint64* oCountWritten)
	{
	uint64 countSkipped;
	iStreamR.Skip(iCount, &countSkipped);
	if (oCountRead)
		*oCountRead = countSkipped;
	if (oCountWritten)
		*oCountWritten = countSkipped;
	}

static void sReadPixmap(const ZStreamR& inStream, ZDCPixmap& outPixmap)
	{
	uint16 rowBytes = inStream.ReadUInt16();
	if (!(rowBytes & 0x8000))
		::sThrowBadFormat();
	rowBytes &= 0x7FFF;

	ZRect bounds;
	bounds.top = inStream.ReadInt16();
	bounds.left = inStream.ReadInt16();
	bounds.bottom = inStream.ReadInt16();
	bounds.right = inStream.ReadInt16();
	inStream.ReadInt16(); // version
	inStream.ReadInt16(); // packType
	inStream.ReadInt32(); // packSize
	inStream.ReadInt32(); // hRes
	inStream.ReadInt32(); //vRes
	short pixelType = inStream.ReadInt16(); // pixelType
	short pixelSize = inStream.ReadInt16(); // pixelSize
	short cmpCount = inStream.ReadInt16(); // cmpCount
	short cmpSize = inStream.ReadInt16(); // cmpSize
	inStream.ReadInt32(); // planeBytes
	inStream.ReadInt32(); // pmTable
	inStream.ReadInt32(); // pmReserved

	// We only deal with pixel type of 0 (indexed pixels)
	if (pixelType != 0)
		::sThrowUnsupportedFormat();

	// indexed pixels have a cmpCount of 1
	if (cmpCount != 1)
		::sThrowBadFormat();

	// pixelSize and cmpSize should be equal for indexed pixels
	if (pixelSize != cmpSize)
		::sThrowBadFormat();

	// Next on the stream is the color table
	vector<ZRGBColor> theColorTable;
	inStream.ReadInt32(); // ctSeed
	inStream.ReadInt16(); // ctFlags
	short ctSize = inStream.ReadInt16();
	for (int i = 0; i <= ctSize; ++i)
		{
		inStream.ReadInt16(); // colorSpecIndex
		ZRGBColor theColor;
		theColor.red = inStream.ReadUInt16();
		theColor.green = inStream.ReadUInt16();
		theColor.blue = inStream.ReadUInt16();
		theColorTable.push_back(theColor);
		}

	// Now we have the source rect
	inStream.Skip(8);

	// and the destination rect
	inStream.Skip(8);

	// Penultimately we have the mode
	inStream.ReadUInt16();

	// The remaining data is the packed pixels. Allocate our ZDCPixmap
	// using the size we read in, but with no initialized data.
	ZDCPixmap thePixmap(bounds.Size(), ZDCPixmapNS::eFormatEfficient_Color_32);
	void* baseAddress = thePixmap.GetBaseAddress();
	ZDCPixmapNS::RasterDesc theRasterDesc = thePixmap.GetRasterDesc();
	ZDCPixmapNS::PixelDesc thePixelDesc = thePixmap.GetPixelDesc();
	::sUnpackFromStream(inStream,
		bounds.Width(), bounds.Height(),
		rowBytes, pixelSize,
		&theColorTable[0], theColorTable.size(),
		baseAddress, theRasterDesc, thePixelDesc);

	outPixmap = thePixmap;
	}