/// <summary>Processes a TIFF data sequence.</summary>
/// <param name="reader">the <see cref="IndexedReader"/> from which the data should be read</param>
/// <param name="handler">the <see cref="ITiffHandler"/> that will coordinate processing and accept read values</param>
/// <exception cref="TiffProcessingException">if an error occurred during the processing of TIFF data that could not be ignored or recovered from</exception>
/// <exception cref="System.IO.IOException">an error occurred while accessing the required data</exception>
/// <exception cref="TiffProcessingException"/>
public static void ProcessTiff(IndexedReader reader, ITiffHandler handler)
{
// Read byte order.
var byteOrder = reader.GetInt16(0);
reader = byteOrder switch
{
0x4d4d => reader.WithByteOrder(isMotorolaByteOrder: true),
0x4949 => reader.WithByteOrder(isMotorolaByteOrder: false),
_ => throw new TiffProcessingException("Unclear distinction between Motorola/Intel byte ordering: " + reader.GetInt16(0)),
};
// Check the next two values for correctness.
int tiffMarker = reader.GetUInt16(2);
handler.SetTiffMarker(tiffMarker);
var firstIfdOffset = reader.GetInt32(4);
// David Ekholm sent a digital camera image that has this problem
// TODO calling Length should be avoided as it causes IndexedCapturingReader to read to the end of the stream
if (firstIfdOffset >= reader.Length - 1)
{
handler.Warn("First IFD offset is beyond the end of the TIFF data segment -- trying default offset");
// First directory normally starts immediately after the offset bytes, so try that
firstIfdOffset = 2 + 2 + 4;
}
var processedIfdOffsets = new HashSet <int>();
ProcessIfd(handler, reader, processedIfdOffsets, firstIfdOffset);
}
/// <summary>Processes a TIFF data sequence.</summary>
/// <param name="reader">the <see cref="IndexedReader"/> from which the data should be read</param>
/// <param name="handler">the <see cref="ITiffHandler"/> that will coordinate processing and accept read values</param>
/// <param name="tiffHeaderOffset">the offset within <c>reader</c> at which the TIFF header starts</param>
/// <exception cref="TiffProcessingException">if an error occurred during the processing of TIFF data that could not be ignored or recovered from</exception>
/// <exception cref="System.IO.IOException">an error occurred while accessing the required data</exception>
/// <exception cref="TiffProcessingException"/>
public static void ProcessTiff([NotNull] IndexedReader reader, [NotNull] ITiffHandler handler, int tiffHeaderOffset = 0)
{
// Read byte order.
switch (reader.GetInt16(tiffHeaderOffset))
{
case 0x4d4d: // MM
reader.IsMotorolaByteOrder = true;
break;
case 0x4949: // II
reader.IsMotorolaByteOrder = false;
break;
default:
throw new TiffProcessingException("Unclear distinction between Motorola/Intel byte ordering: " + reader.GetInt16(tiffHeaderOffset));
}
// Check the next two values for correctness.
int tiffMarker = reader.GetUInt16(2 + tiffHeaderOffset);
handler.SetTiffMarker(tiffMarker);
var firstIfdOffset = reader.GetInt32(4 + tiffHeaderOffset) + tiffHeaderOffset;
// David Ekholm sent a digital camera image that has this problem
// TODO calling Length should be avoided as it causes IndexedCapturingReader to read to the end of the stream
if (firstIfdOffset >= reader.Length - 1)
{
handler.Warn("First IFD offset is beyond the end of the TIFF data segment -- trying default offset");
// First directory normally starts immediately after the offset bytes, so try that
firstIfdOffset = tiffHeaderOffset + 2 + 2 + 4;
}
var processedIfdOffsets = new HashSet <int>();
ProcessIfd(handler, reader, processedIfdOffsets, firstIfdOffset, tiffHeaderOffset);
handler.Completed(reader, tiffHeaderOffset);
}
