Esempio n. 1
0
        /// <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);
        }
Esempio n. 2
0
        /// <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);
        }