internal void Write(BitWriter writer, int offsetAdjustment) { var startOffset = writer.Position; writer.WriteBytes(StartSentinel); var imageCount = 0; if (HeaderData?.Length > 0) { imageCount++; } if (BmpData?.Length > 0) { imageCount++; } if (WmfData?.Length > 0) { imageCount++; } var imageControlByteCount = imageCount * (1 + 4 + 4) + // each set of data writes a byte and two ints 1; // `imageCount` below var overallSize = imageControlByteCount + (HeaderData?.Length ?? 0) + (BmpData?.Length ?? 0) + (WmfData?.Length ?? 0); writer.Write_RL(overallSize); writer.Write_RC((byte)imageCount); if (HeaderData?.Length > 0) { writer.Write_RC(1); writer.Write_RL(writer.Position - startOffset + offsetAdjustment); // start writer.Write_RL(HeaderData.Length); } if (BmpData?.Length > 0) { writer.Write_RC(2); writer.Write_RL(writer.Position - startOffset + offsetAdjustment); // start writer.Write_RL(BmpData.Length); } if (WmfData?.Length > 0) { writer.Write_RC(3); writer.Write_RL(writer.Position - startOffset + offsetAdjustment); // start writer.Write_RL(WmfData.Length); } writer.WriteBytes(EndSentinel); }
internal void Write(BitWriter writer, DwgVersionId version) { writer.AlignByte(); using (var ms = new MemoryStream()) { // write the variables to memory var variableWriter = new BitWriter(ms); WriteVariables(variableWriter, version); var variableBytes = variableWriter.AsBytes(); // now write it all out writer.WriteBytes(StartSentinel); writer.StartCrcCalculation(initialValue: InitialCrcValue); writer.Write_RL(variableBytes.Length); writer.WriteBytes(variableBytes); writer.WriteCrc(); writer.WriteBytes(EndSentinel); } }
internal static void Write(IList <DwgClassDefinition> classes, BitWriter writer) { writer.AlignByte(); using (var ms = new MemoryStream()) { // write the classes to memory var classWriter = new BitWriter(ms); foreach (var c in classes) { c.Write(classWriter); } var classBytes = classWriter.AsBytes(); // now write it all out writer.WriteBytes(StartSentinel); writer.StartCrcCalculation(initialValue: DwgHeaderVariables.InitialCrcValue); writer.Write_RL(classBytes.Length); writer.WriteBytes(classBytes); writer.WriteCrc(); writer.WriteBytes(EndSentinel); } }
internal void WriteSecondHeader(BitWriter writer, DwgHeaderVariables headerVariables, int pointer) { // write to memory the backtrack to fill in size and crc using (var ms = new MemoryStream()) { var tempWriter = new BitWriter(ms); tempWriter.WriteBytes(SecondHeaderStartSentinel); var sizeOffset = tempWriter.Position; tempWriter.Write_RL(0); // size, filled in later tempWriter.Write_BL(pointer); tempWriter.WriteStringAscii(Version.VersionString(), nullTerminated: false); tempWriter.WriteBytes(new byte[] { 0, 0, 0, 0, 0, 0 }); // 6 zero bytes tempWriter.WriteBits(0x00000000, 4); // 4 zero bits tempWriter.WriteBytes(new byte[] { 0, 0 }); // 2 unknown bytes tempWriter.WriteBytes(SecondHeaderMidSentinel); tempWriter.WriteByte(5); // record locator count HeaderVariablesLocator.Write(tempWriter, writingSecondHeader: true); ClassSectionLocator.Write(tempWriter, writingSecondHeader: true); ObjectMapLocator.Write(tempWriter, writingSecondHeader: true); UnknownSection_R13C3AndLaterLocator.Write(tempWriter, writingSecondHeader: true); UnknownSection_PaddingLocator.Write(tempWriter, writingSecondHeader: true); tempWriter.Write_BS(14); headerVariables.NextAvailableHandle.WriteSecondHeader(tempWriter, 0); headerVariables.BlockControlObjectHandle.WriteSecondHeader(tempWriter, 1); headerVariables.LayerControlObjectHandle.WriteSecondHeader(tempWriter, 2); headerVariables.StyleObjectControlHandle.WriteSecondHeader(tempWriter, 3); headerVariables.LineTypeObjectControlHandle.WriteSecondHeader(tempWriter, 4); headerVariables.ViewControlObjectHandle.WriteSecondHeader(tempWriter, 5); headerVariables.UcsControlObjectHandle.WriteSecondHeader(tempWriter, 6); headerVariables.ViewPortControlObjectHandle.WriteSecondHeader(tempWriter, 7); headerVariables.AppIdControlObjectHandle.WriteSecondHeader(tempWriter, 8); headerVariables.DimStyleControlObjectHandle.WriteSecondHeader(tempWriter, 9); headerVariables.ViewPortEntityHeaderControlObjectHandle.WriteSecondHeader(tempWriter, 10); headerVariables.NamedObjectsDictionaryHandle.WriteSecondHeader(tempWriter, 11); headerVariables.MLineStyleDictionaryHandle.WriteSecondHeader(tempWriter, 12); headerVariables.GroupDictionaryHandle.WriteSecondHeader(tempWriter, 13); tempWriter.WriteByte(0); // unknown tempWriter.AlignByte(); var crcOffset = tempWriter.Position; tempWriter.WriteShort(0); // CRC, filled in later if (Version == DwgVersionId.R14) { // unknown garbage bytes tempWriter.WriteBytes(new byte[] { 0, 0, 0, 0, 0, 0, 0, 0 }); } tempWriter.WriteBytes(SecondHeaderEndSentinel); // get bytes of header var secondHeaderBytes = tempWriter.AsBytes(); // fill in size var sizeBytes = BitConverter.GetBytes(secondHeaderBytes.Length - SecondHeaderStartSentinel.Length - SecondHeaderEndSentinel.Length); if (!BitConverter.IsLittleEndian) { Array.Reverse(sizeBytes); } Array.Copy(sizeBytes, 0, secondHeaderBytes, sizeOffset, sizeBytes.Length); // fill in crc var crc = BitReaderExtensions.ComputeCRC(secondHeaderBytes, sizeOffset, crcOffset - sizeOffset, DwgHeaderVariables.InitialCrcValue); var crcBytes = BitConverter.GetBytes(crc); if (!BitConverter.IsLittleEndian) { Array.Reverse(crcBytes); } Array.Copy(crcBytes, 0, secondHeaderBytes, crcOffset, crcBytes.Length); // write to the real writer writer.WriteBytes(secondHeaderBytes); } }