BitMiracle.LibJpeg.Classic.jpeg_decompress_struct.jpeg_read_scanlines C# (CSharp) Method

        public int jpeg_read_scanlines(byte[][] scanlines, int max_lines)
        {
            if (m_global_state != JpegState.DSTATE_SCANNING)
                ERREXIT(J_MESSAGE_CODE.JERR_BAD_STATE, (int)m_global_state);

            if (m_output_scanline >= m_output_height)
            {
                WARNMS(J_MESSAGE_CODE.JWRN_TOO_MUCH_DATA);
                return 0;
            }

            /* Call progress monitor hook if present */
            if (m_progress != null)
            {
                m_progress.Pass_counter = m_output_scanline;
                m_progress.Pass_limit = m_output_height;
                m_progress.Updated();
            }

            /* Process some data */
            int row_ctr = 0;
            m_main.process_data(scanlines, ref row_ctr, max_lines);
            m_output_scanline += row_ctr;
            return row_ctr;
        }

        private static void decompress(Stream input, DecompressOptions options, Stream output)
        {
            Debug.Assert(input != null);
            Debug.Assert(options != null);
            Debug.Assert(output != null);

            /* Initialize the JPEG decompression object with default error handling. */
            jpeg_decompress_struct cinfo = new jpeg_decompress_struct(new cd_jpeg_error_mgr());

            /* Insert custom marker processor for COM and APP12.
             * APP12 is used by some digital camera makers for textual info,
             * so we provide the ability to display it as text.
             * If you like, additional APPn marker types can be selected for display,
             * but don't try to override APP0 or APP14 this way (see libjpeg.doc).
             */
            cinfo.jpeg_set_marker_processor((int)JPEG_MARKER.COM, new jpeg_decompress_struct.jpeg_marker_parser_method(printTextMarker));
            cinfo.jpeg_set_marker_processor((int)JPEG_MARKER.APP0 + 12, printTextMarker);

            /* Specify data source for decompression */
            cinfo.jpeg_stdio_src(input);

            /* Read file header, set default decompression parameters */
            cinfo.jpeg_read_header(true);

            applyOptions(cinfo, options);

            /* Initialize the output module now to let it override any crucial
             * option settings (for instance, GIF wants to force color quantization).
             */
            djpeg_dest_struct dest_mgr = null;

            switch (options.OutputFormat)
            {
                case IMAGE_FORMATS.FMT_BMP:
                    dest_mgr = new bmp_dest_struct(cinfo, false);
                    break;
                case IMAGE_FORMATS.FMT_OS2:
                    dest_mgr = new bmp_dest_struct(cinfo, true);
                    break;
                default:
                    cinfo.ERREXIT((int)ADDON_MESSAGE_CODE.JERR_UNSUPPORTED_FORMAT);
                    break;
            }

            dest_mgr.output_file = output;

            /* Start decompressor */
            cinfo.jpeg_start_decompress();

            /* Write output file header */
            dest_mgr.start_output();

            /* Process data */
            while (cinfo.Output_scanline < cinfo.Output_height)
            {
                int num_scanlines = cinfo.jpeg_read_scanlines(dest_mgr.buffer, dest_mgr.buffer_height);
                dest_mgr.put_pixel_rows(num_scanlines);
            }

            /* Finish decompression and release memory.
             * I must do it in this order because output module has allocated memory
             * of lifespan JPOOL_IMAGE; it needs to finish before releasing memory.
             */
            dest_mgr.finish_output();
            cinfo.jpeg_finish_decompress();

            /* All done. */
            if (cinfo.Err.Num_warnings != 0)
                Console.WriteLine("Corrupt-data warning count is not zero");
        }