public JpegXmpPackets GetXmpPackets()
{
if (!fileParsed)
{
ParseFile();
fileParsed = true;
}
if (mainXmpPacket == null)
{
// The file does not contain any XMP data.
return(null);
}
if (mergedXmpPacket == null)
{
if (extendedXmpPacket != null)
{
mergedXmpPacket = XmpUtil.MergeExtendedXmp(mainXmpPacket, extendedXmpPacket);
}
else
{
mergedXmpPacket = mainXmpPacket.Clone();
}
}
return(new JpegXmpPackets(mainXmpPacket, extendedXmpPacket, mergedXmpPacket));
}
private void GatherXmpDataFromFile(EndianBinaryReader reader)
{
ushort marker = reader.ReadUInt16();
// Check the file signature.
if (marker == JpegMarkers.StartOfImage)
{
while (reader.Position < reader.Length)
{
marker = reader.ReadUInt16();
if (marker == 0xFFFF)
{
// Skip the first padding byte and read the marker again.
reader.Position++;
continue;
}
if (marker == JpegMarkers.StartOfScan || marker == JpegMarkers.EndOfImage)
{
// The application data segments always come before these markers.
break;
}
ushort segmentLength = reader.ReadUInt16();
if (segmentLength < 2)
{
ExceptionUtil.ThrowFormatException($"JPEG segment length must be in the range of [2, 65535], actual value: { segmentLength }");
}
// The segment length field includes its own length in the total.
segmentLength -= sizeof(ushort);
if (marker == JpegMarkers.App1)
{
if (mainXmpPacket == null && segmentLength >= MainXmpSignatureLength)
{
string sig = reader.ReadAsciiString(MainXmpSignatureLength);
if (sig.Equals(MainXmpSignature, StringComparison.Ordinal))
{
byte[] xmpPacketBytes = reader.ReadBytes(segmentLength - MainXmpSignatureLength);
mainXmpPacket = new XmpPacket(xmpPacketBytes);
extendedXmpGuid = XmpUtil.GetExtendedXmpGuid(mainXmpPacket);
continue;
}
else
{
reader.Position -= MainXmpSignatureLength;
}
}
if (segmentLength >= ExtendedXmpPrefixLength)
{
string sig = reader.ReadAsciiString(ExtendedXmpSignatureLength);
if (sig.Equals(ExtendedXmpSignature, StringComparison.Ordinal))
{
string guid = reader.ReadAsciiString(ExtendedXmpGUIDLength);
uint length = reader.ReadUInt32();
uint offset = reader.ReadUInt32();
byte[] data = reader.ReadBytes(segmentLength - ExtendedXmpPrefixLength);
if (extendedXmpChunks.TryGetValue(guid, out ExtendedXmp value))
{
value.AddChunk(data, offset, length);
}
else
{
extendedXmpChunks.Add(guid, new ExtendedXmp(data, offset, length));
}
continue;
}
else
{
segmentLength -= ExtendedXmpSignatureLength;
}
}
}
reader.Position += segmentLength;
}
}
}
