private void ProcessFrameHeader(ref JpegReader reader, bool metadataOnly, bool overrideAllowed)
{
// Read length field
if (!reader.TryReadLength(out ushort length))
{
ThrowInvalidDataException(reader.ConsumedByteCount, "Unexpected end of input data when reading segment length.");
return;
}
if (!reader.TryReadBytes(length, out ReadOnlySequence <byte> buffer))
{
ThrowInvalidDataException(reader.ConsumedByteCount, "Unexpected end of input data when reading segment content.");
return;
}
if (!JpegFrameHeader.TryParse(buffer, metadataOnly, out JpegFrameHeader frameHeader, out int bytesConsumed))
{
ThrowInvalidDataException(reader.ConsumedByteCount - length + bytesConsumed, "Failed to parse frame header.");
return;
}
if (!overrideAllowed && _frameHeader.HasValue)
{
ThrowInvalidDataException(reader.ConsumedByteCount, "Multiple frame is not supported.");
return;
}
_frameHeader = frameHeader;
}
private void ProcessDefineQuantizationTable(ref JpegReader reader)
{
if (!reader.TryReadLength(out ushort length))
{
ThrowInvalidDataException(reader.ConsumedByteCount, "Unexpected end of input data when reading segment length.");
return;
}
if (!reader.TryReadBytes(length, out ReadOnlySequence <byte> buffer))
{
ThrowInvalidDataException(reader.ConsumedByteCount, "Unexpected end of input data when reading segment content.");
return;
}
ProcessDefineQuantizationTable(buffer, reader.ConsumedByteCount - length);
}
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);
}
private JpegScanHeader ProcessScanHeader(ref JpegReader reader, bool metadataOnly)
{
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.");
}
if (!JpegScanHeader.TryParse(buffer, metadataOnly, out JpegScanHeader scanHeader, out int bytesConsumed))
{
ThrowInvalidDataException(reader.ConsumedByteCount - length + bytesConsumed, "Failed to parse scan header.");
}
return(scanHeader);
}
private void ProcessDefineRestartInterval(ref JpegReader reader)
{
if (!reader.TryReadLength(out ushort length))
{
ThrowInvalidDataException(reader.ConsumedByteCount, "Unexpected end of input data when reading segment length.");
return;
}
if (!reader.TryReadBytes(length, out ReadOnlySequence <byte> buffer) || buffer.Length < 2)
{
ThrowInvalidDataException(reader.ConsumedByteCount, "Unexpected end of input data when reading segment content.");
return;
}
Span <byte> local = stackalloc byte[2];
buffer.Slice(0, 2).CopyTo(local);
_restartInterval = BinaryPrimitives.ReadUInt16BigEndian(local);
}
