private void WriteQuantizationTables(ref JpegWriter writer)
{
List <JpegQuantizationTable>?quantizationTables = _quantizationTables;
if (quantizationTables is null)
{
throw new InvalidOperationException();
}
writer.WriteMarker(JpegMarker.DefineQuantizationTable);
ushort totalByteCount = 0;
foreach (JpegQuantizationTable table in quantizationTables)
{
totalByteCount += table.BytesRequired;
}
writer.WriteLength(totalByteCount);
foreach (JpegQuantizationTable table in quantizationTables)
{
Span <byte> buffer = writer.GetSpan(table.BytesRequired);
table.TryWrite(buffer, out int bytesWritten);
writer.Advance(bytesWritten);
}
}
private void WriteHuffmanTables(ref JpegWriter writer)
{
if (_encodingTables.IsEmpty)
{
throw new InvalidOperationException();
}
writer.WriteMarker(JpegMarker.DefineHuffmanTable);
ushort totalByteCoubt = _encodingTables.GetTotalBytesRequired();
writer.WriteLength(totalByteCoubt);
_encodingTables.Write(ref writer);
}
private static ReadOnlySequence <byte> CopyMarkerData(ref JpegReader reader, ref JpegWriter writer)
{
if (!reader.TryReadLength(out ushort length))
{
ThrowInvalidDataException(reader.ConsumedByteCount, "Unexpected end of input data when reading segment length.");
}
if (!reader.TryReadBytes(length, out ReadOnlySequence <byte> buffer))
{
ThrowInvalidDataException(reader.ConsumedByteCount, "Unexpected end of input data when reading segment content.");
}
writer.WriteLength(length);
writer.WriteBytes(buffer);
return(buffer);
}
