/// <summary>
/// Load quantization and/or Huffman tables for subsequent use for jpeg's embedded in tiff's,
/// so those tables do not need to be duplicated with segmented tiff's (tiff's with multiple strips).
/// </summary>
/// <param name="tableBytes">The table bytes.</param>
/// <param name="huffmanScanDecoder">The scan decoder.</param>
public void LoadTables(byte[] tableBytes, HuffmanScanDecoder huffmanScanDecoder)
{
this.Metadata = new ImageMetadata();
this.QuantizationTables = new Block8x8F[4];
this.scanDecoder = huffmanScanDecoder;
using var ms = new MemoryStream(tableBytes);
using var stream = new BufferedReadStream(this.Configuration, ms);
// Check for the Start Of Image marker.
stream.Read(this.markerBuffer, 0, 2);
var fileMarker = new JpegFileMarker(this.markerBuffer[1], 0);
if (fileMarker.Marker != JpegConstants.Markers.SOI)
{
JpegThrowHelper.ThrowInvalidImageContentException("Missing SOI marker.");
}
// Read next marker.
stream.Read(this.markerBuffer, 0, 2);
byte marker = this.markerBuffer[1];
fileMarker = new JpegFileMarker(marker, (int)stream.Position - 2);
while (fileMarker.Marker != JpegConstants.Markers.EOI || (fileMarker.Marker == JpegConstants.Markers.EOI && fileMarker.Invalid))
{
if (!fileMarker.Invalid)
{
// Get the marker length.
int remaining = this.ReadUint16(stream) - 2;
switch (fileMarker.Marker)
{
case JpegConstants.Markers.SOI:
break;
case JpegConstants.Markers.RST0:
case JpegConstants.Markers.RST7:
break;
case JpegConstants.Markers.DHT:
this.ProcessDefineHuffmanTablesMarker(stream, remaining);
break;
case JpegConstants.Markers.DQT:
this.ProcessDefineQuantizationTablesMarker(stream, remaining);
break;
case JpegConstants.Markers.DRI:
this.ProcessDefineRestartIntervalMarker(stream, remaining);
break;
case JpegConstants.Markers.EOI:
return;
}
}
// Read next marker.
stream.Read(this.markerBuffer, 0, 2);
fileMarker = new JpegFileMarker(this.markerBuffer[1], 0);
}
}
/// <inheritdoc/>
public Image <TPixel> Decode <TPixel>(Configuration configuration, Stream stream)
where TPixel : unmanaged, IPixel <TPixel>
{
Guard.NotNull(stream, nameof(stream));
using var decoder = new JpegDecoderCore(configuration, this);
try
{
return(decoder.Decode <TPixel>(stream));
}
catch (InvalidMemoryOperationException ex)
{
(int w, int h) = (decoder.ImageWidth, decoder.ImageHeight);
JpegThrowHelper.ThrowInvalidImageContentException($"Can not decode image. Failed to allocate buffers for possibly degenerate dimensions: {w}x{h}.", ex);
// Not reachable, as the previous statement will throw a exception.
return(null);
}
}
/// <summary>
/// Parses the input stream for file markers.
/// </summary>
/// <param name="stream">The input stream.</param>
/// <param name="scanDecoder">Scan decoder used exclusively to decode SOS marker.</param>
/// <param name="cancellationToken">The token to monitor cancellation.</param>
internal void ParseStream(BufferedReadStream stream, HuffmanScanDecoder scanDecoder, CancellationToken cancellationToken)
{
bool metadataOnly = scanDecoder == null;
this.scanDecoder = scanDecoder;
this.Metadata = new ImageMetadata();
// Check for the Start Of Image marker.
stream.Read(this.markerBuffer, 0, 2);
var fileMarker = new JpegFileMarker(this.markerBuffer[1], 0);
if (fileMarker.Marker != JpegConstants.Markers.SOI)
{
JpegThrowHelper.ThrowInvalidImageContentException("Missing SOI marker.");
}
stream.Read(this.markerBuffer, 0, 2);
byte marker = this.markerBuffer[1];
fileMarker = new JpegFileMarker(marker, (int)stream.Position - 2);
this.QuantizationTables ??= new Block8x8F[4];
// Break only when we discover a valid EOI marker.
// https://github.com/SixLabors/ImageSharp/issues/695
while (fileMarker.Marker != JpegConstants.Markers.EOI
|| (fileMarker.Marker == JpegConstants.Markers.EOI && fileMarker.Invalid))
{
cancellationToken.ThrowIfCancellationRequested();
if (!fileMarker.Invalid)
{
// Get the marker length.
int remaining = this.ReadUint16(stream) - 2;
switch (fileMarker.Marker)
{
case JpegConstants.Markers.SOF0:
case JpegConstants.Markers.SOF1:
case JpegConstants.Markers.SOF2:
this.ProcessStartOfFrameMarker(stream, remaining, fileMarker, metadataOnly);
break;
case JpegConstants.Markers.SOF5:
JpegThrowHelper.ThrowNotSupportedException("Decoding jpeg files with differential sequential DCT is not supported.");
break;
case JpegConstants.Markers.SOF6:
JpegThrowHelper.ThrowNotSupportedException("Decoding jpeg files with differential progressive DCT is not supported.");
break;
case JpegConstants.Markers.SOF3:
case JpegConstants.Markers.SOF7:
JpegThrowHelper.ThrowNotSupportedException("Decoding lossless jpeg files is not supported.");
break;
case JpegConstants.Markers.SOF9:
case JpegConstants.Markers.SOF10:
case JpegConstants.Markers.SOF11:
case JpegConstants.Markers.SOF13:
case JpegConstants.Markers.SOF14:
case JpegConstants.Markers.SOF15:
JpegThrowHelper.ThrowNotSupportedException("Decoding jpeg files with arithmetic coding is not supported.");
break;
case JpegConstants.Markers.SOS:
if (!metadataOnly)
{
this.ProcessStartOfScanMarker(stream, remaining);
break;
}
else
{
// It's highly unlikely that APPn related data will be found after the SOS marker
// We should have gathered everything we need by now.
return;
}
case JpegConstants.Markers.DHT:
if (metadataOnly)
{
stream.Skip(remaining);
}
else
{
this.ProcessDefineHuffmanTablesMarker(stream, remaining);
}
break;
case JpegConstants.Markers.DQT:
this.ProcessDefineQuantizationTablesMarker(stream, remaining);
break;
case JpegConstants.Markers.DRI:
if (metadataOnly)
{
stream.Skip(remaining);
}
else
{
this.ProcessDefineRestartIntervalMarker(stream, remaining);
}
break;
case JpegConstants.Markers.APP0:
this.ProcessApplicationHeaderMarker(stream, remaining);
break;
case JpegConstants.Markers.APP1:
this.ProcessApp1Marker(stream, remaining);
break;
case JpegConstants.Markers.APP2:
this.ProcessApp2Marker(stream, remaining);
break;
case JpegConstants.Markers.APP3:
case JpegConstants.Markers.APP4:
case JpegConstants.Markers.APP5:
case JpegConstants.Markers.APP6:
case JpegConstants.Markers.APP7:
case JpegConstants.Markers.APP8:
case JpegConstants.Markers.APP9:
case JpegConstants.Markers.APP10:
case JpegConstants.Markers.APP11:
case JpegConstants.Markers.APP12:
stream.Skip(remaining);
break;
case JpegConstants.Markers.APP13:
this.ProcessApp13Marker(stream, remaining);
break;
case JpegConstants.Markers.APP14:
this.ProcessApp14Marker(stream, remaining);
break;
case JpegConstants.Markers.APP15:
case JpegConstants.Markers.COM:
stream.Skip(remaining);
break;
case JpegConstants.Markers.DAC:
JpegThrowHelper.ThrowNotSupportedException("Decoding jpeg files with arithmetic coding is not supported.");
break;
}
}
// Read on.
fileMarker = FindNextFileMarker(this.markerBuffer, stream);
}
}
/// <summary>
/// Parses the input stream for file markers
/// </summary>
/// <param name="stream">The input stream</param>
/// <param name="metadataOnly">Whether to decode metadata only.</param>
public void ParseStream(Stream stream, bool metadataOnly = false)
{
this.Metadata = new ImageMetadata();
this.InputStream = new DoubleBufferedStreamReader(this.Configuration.MemoryAllocator, stream);
// Check for the Start Of Image marker.
this.InputStream.Read(this.markerBuffer, 0, 2);
var fileMarker = new JpegFileMarker(this.markerBuffer[1], 0);
if (fileMarker.Marker != JpegConstants.Markers.SOI)
{
JpegThrowHelper.ThrowInvalidImageContentException("Missing SOI marker.");
}
this.InputStream.Read(this.markerBuffer, 0, 2);
byte marker = this.markerBuffer[1];
fileMarker = new JpegFileMarker(marker, (int)this.InputStream.Position - 2);
this.QuantizationTables = new Block8x8F[4];
// Only assign what we need
if (!metadataOnly)
{
const int maxTables = 4;
this.dcHuffmanTables = new HuffmanTable[maxTables];
this.acHuffmanTables = new HuffmanTable[maxTables];
}
// Break only when we discover a valid EOI marker.
// https://github.com/SixLabors/ImageSharp/issues/695
while (fileMarker.Marker != JpegConstants.Markers.EOI ||
(fileMarker.Marker == JpegConstants.Markers.EOI && fileMarker.Invalid))
{
if (!fileMarker.Invalid)
{
// Get the marker length
int remaining = this.ReadUint16() - 2;
switch (fileMarker.Marker)
{
case JpegConstants.Markers.SOF0:
case JpegConstants.Markers.SOF1:
case JpegConstants.Markers.SOF2:
this.ProcessStartOfFrameMarker(remaining, fileMarker, metadataOnly);
break;
case JpegConstants.Markers.SOS:
if (!metadataOnly)
{
this.ProcessStartOfScanMarker();
break;
}
else
{
// It's highly unlikely that APPn related data will be found after the SOS marker
// We should have gathered everything we need by now.
return;
}
case JpegConstants.Markers.DHT:
if (metadataOnly)
{
this.InputStream.Skip(remaining);
}
else
{
this.ProcessDefineHuffmanTablesMarker(remaining);
}
break;
case JpegConstants.Markers.DQT:
this.ProcessDefineQuantizationTablesMarker(remaining);
break;
case JpegConstants.Markers.DRI:
if (metadataOnly)
{
this.InputStream.Skip(remaining);
}
else
{
this.ProcessDefineRestartIntervalMarker(remaining);
}
break;
case JpegConstants.Markers.APP0:
this.ProcessApplicationHeaderMarker(remaining);
break;
case JpegConstants.Markers.APP1:
this.ProcessApp1Marker(remaining);
break;
case JpegConstants.Markers.APP2:
this.ProcessApp2Marker(remaining);
break;
case JpegConstants.Markers.APP3:
case JpegConstants.Markers.APP4:
case JpegConstants.Markers.APP5:
case JpegConstants.Markers.APP6:
case JpegConstants.Markers.APP7:
case JpegConstants.Markers.APP8:
case JpegConstants.Markers.APP9:
case JpegConstants.Markers.APP10:
case JpegConstants.Markers.APP11:
case JpegConstants.Markers.APP12:
this.InputStream.Skip(remaining);
break;
case JpegConstants.Markers.APP13:
this.ProcessApp13Marker(remaining);
break;
case JpegConstants.Markers.APP14:
this.ProcessApp14Marker(remaining);
break;
case JpegConstants.Markers.APP15:
case JpegConstants.Markers.COM:
this.InputStream.Skip(remaining);
break;
}
}
// Read on.
fileMarker = FindNextFileMarker(this.markerBuffer, this.InputStream);
}
}