/*
    *  Licensed under the Apache License, Version 2.0 (the "License");
    *  you may not use this file except in compliance with the License.
    *  You may obtain a copy of the License at
    *
    *       http://www.apache.org/licenses/LICENSE-2.0
    *
    *  Unless required by applicable law or agreed to in writing, software
    *  distributed under the License is distributed on an "AS IS" BASIS,
   *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   *  See the License for the specific language governing permissions and
   *  limitations under the License.
   *  under the License.
   */
  
  package org.apache.commons.imaging.formats.jpeg.decoder;
  
  import static org.apache.commons.imaging.common.BinaryFunctions.read2Bytes;
  import static org.apache.commons.imaging.common.BinaryFunctions.readBytes;
  
  import java.awt.image.BufferedImage;
  import java.awt.image.ColorModel;
  import java.awt.image.DataBuffer;
  import java.awt.image.DirectColorModel;
  import java.awt.image.Raster;
  import java.awt.image.WritableRaster;
  import java.io.ByteArrayInputStream;
  import java.io.IOException;
  import java.util.ArrayList;
  import java.util.Arrays;
  import java.util.List;
  import java.util.Properties;
  
  import org.apache.commons.imaging.ImagingException;
  import org.apache.commons.imaging.bytesource.ByteSource;
  import org.apache.commons.imaging.color.ColorConversions;
  import org.apache.commons.imaging.common.Allocator;
  import org.apache.commons.imaging.common.BinaryFileParser;
  import org.apache.commons.imaging.formats.jpeg.JpegConstants;
  import org.apache.commons.imaging.formats.jpeg.JpegUtils;
  import org.apache.commons.imaging.formats.jpeg.segments.DhtSegment;
  import org.apache.commons.imaging.formats.jpeg.segments.DhtSegment.HuffmanTable;
  import org.apache.commons.imaging.formats.jpeg.segments.DqtSegment;
  import org.apache.commons.imaging.formats.jpeg.segments.DqtSegment.QuantizationTable;
  import org.apache.commons.imaging.formats.jpeg.segments.SofnSegment;
  import org.apache.commons.imaging.formats.jpeg.segments.SosSegment;
  
  public class JpegDecoder extends BinaryFileParser implements JpegUtils.Visitor {
  
      private static final int[] BAND_MASK_ARGB = { 0x00ff0000, 0x0000ff00, 0x000000ff, 0xff000000 };
      private static final int[] BAND_MASK_RGB = { 0x00ff0000, 0x0000ff00, 0x000000ff };
  
      /*
       * JPEG is an advanced image format that takes significant computation to decode. Keep decoding fast: - Don't allocate memory inside loops, allocate it once
       * and reuse. - Minimize calculations per pixel and per block (using lookup tables for YCbCr->RGB conversion doubled performance). - Math.round() is slow,
       * use (int)(x+0.5f) instead for positive numbers.
       */
  
      private static int fastRound(final float x) {
          return (int) (x + 0.5f);
      }
  
      /**
       * Returns the positions of where each interval in the provided array starts. The number of start positions is also the count of intervals while the number
       * of restart markers found is equal to the number of start positions minus one (because restart markers are between intervals).
       *
       * @param scanPayload array to examine
       * @return the start positions
       */
      static List<Integer> getIntervalStartPositions(final int[] scanPayload) {
          final List<Integer> intervalStarts = new ArrayList<>();
          intervalStarts.add(0);
          boolean foundFF = false;
          boolean foundD0toD7 = false;
          int pos = 0;
          while (pos < scanPayload.length) {
              if (foundFF) {
                  // found 0xFF D0 .. 0xFF D7 => RST marker
                  if (scanPayload[pos] >= (0xff & JpegConstants.RST0_MARKER) && scanPayload[pos] <= (0xff & JpegConstants.RST7_MARKER)) {
                      foundD0toD7 = true;
                  } else { // found 0xFF followed by something else => no RST marker
                      foundFF = false;
                  }
              }
  
              if (scanPayload[pos] == 0xFF) {
                  foundFF = true;
              }
  
              // true if one of the RST markers was found
              if (foundFF && foundD0toD7) {
                  // we need to add the position after the current position because
                  // we had already read 0xFF and are now at 0xDn
                  intervalStarts.add(pos + 1);
                  foundFF = foundD0toD7 = false;
              }
              pos++;
          }
          return intervalStarts;
     }
 
     /**
      * Returns an array of JpegInputStream where each field contains the JpegInputStream for one interval.
      *
      * @param scanPayload array to read intervals from
      * @return JpegInputStreams for all intervals, at least one stream is always provided
      */
     static JpegInputStream[] splitByRstMarkers(final int[] scanPayload) {
         final List<Integer> intervalStarts = getIntervalStartPositions(scanPayload);
         // get number of intervals in payload to init an array of appropriate length
         final int intervalCount = intervalStarts.size();
         final JpegInputStream[] streams = Allocator.array(intervalCount, JpegInputStream[]::new, JpegInputStream.SHALLOW_SIZE);
         for (int i = 0; i < intervalCount; i++) {
             final int from = intervalStarts.get(i);
             final int to;
             if (i < intervalCount - 1) {
                 // because each restart marker needs two bytes the end of
                 // this interval is two bytes before the next interval starts
                 to = intervalStarts.get(i + 1) - 2;
             } else { // the last interval ends with the array
                 to = scanPayload.length;
             }
             final int[] interval = Arrays.copyOfRange(scanPayload, from, to);
             streams[i] = new JpegInputStream(interval);
         }
         return streams;
     }
 
     private final DqtSegment.QuantizationTable[] quantizationTables = new DqtSegment.QuantizationTable[4];
     private final DhtSegment.HuffmanTable[] huffmanDCTables = new DhtSegment.HuffmanTable[4];
     private final DhtSegment.HuffmanTable[] huffmanACTables = new DhtSegment.HuffmanTable[4];
     private SofnSegment sofnSegment;
     private SosSegment sosSegment;
     private final float[][] scaledQuantizationTables = new float[4][];
     private BufferedImage image;
     private ImagingException imageReadException;
     private IOException ioException;
 
     private final int[] zz = new int[64];
 
     private final int[] blockInt = new int[64];
 
     private final float[] block = new float[64];
 
     private boolean useTiffRgb;
 
     /**
      * Constructs a new instance with the default, big-endian, byte order.
      */
     public JpegDecoder() {
         // empty
     }
 
     private Block[] allocateMcuMemory() throws ImagingException {
         final Block[] mcu = Allocator.array(sosSegment.numberOfComponents, Block[]::new, Block.SHALLOW_SIZE);
         for (int i = 0; i < sosSegment.numberOfComponents; i++) {
             final SosSegment.Component scanComponent = sosSegment.getComponents(i);
             SofnSegment.Component frameComponent = null;
             for (int j = 0; j < sofnSegment.numberOfComponents; j++) {
                 if (sofnSegment.getComponents(j).componentIdentifier == scanComponent.scanComponentSelector) {
                     frameComponent = sofnSegment.getComponents(j);
                     break;
                 }
             }
             if (frameComponent == null) {
                 throw new ImagingException("Invalid component");
             }
             final Block fullBlock = new Block(8 * frameComponent.horizontalSamplingFactor, 8 * frameComponent.verticalSamplingFactor);
             mcu[i] = fullBlock;
         }
         return mcu;
     }
 
     @Override
     public boolean beginSos() {
         return true;
     }
 
     public BufferedImage decode(final ByteSource byteSource) throws IOException, ImagingException {
         final JpegUtils jpegUtils = new JpegUtils();
         jpegUtils.traverseJfif(byteSource, this);
         if (imageReadException != null) {
             throw imageReadException;
         }
         if (ioException != null) {
             throw ioException;
         }
         return image;
     }
 
     private int decode(final JpegInputStream is, final DhtSegment.HuffmanTable huffmanTable) throws ImagingException {
         // "DECODE", section F.2.2.3, figure F.16, page 109 of T.81
         int i = 1;
         int code = is.nextBit();
         while (code > huffmanTable.getMaxCode(i)) {
             i++;
             code = code << 1 | is.nextBit();
         }
         int j = huffmanTable.getValPtr(i);
         j += code - huffmanTable.getMinCode(i);
         return huffmanTable.getHuffVal(j);
     }
 
     private int extend(int v, final int t) {
         // "EXTEND", section F.2.2.1, figure F.12, page 105 of T.81
         int vt = 1 << t - 1;
         if (v < vt) {
             vt = (-1 << t) + 1;
             v += vt;
         }
         return v;
     }
 
     private void readMcu(final JpegInputStream is, final int[] preds, final Block[] mcu) throws ImagingException {
         for (int i = 0; i < sosSegment.numberOfComponents; i++) {
             final SosSegment.Component scanComponent = sosSegment.getComponents(i);
             SofnSegment.Component frameComponent = null;
             for (int j = 0; j < sofnSegment.numberOfComponents; j++) {
                 if (sofnSegment.getComponents(j).componentIdentifier == scanComponent.scanComponentSelector) {
                     frameComponent = sofnSegment.getComponents(j);
                     break;
                 }
             }
             if (frameComponent == null) {
                 throw new ImagingException("Invalid component");
             }
             final Block fullBlock = mcu[i];
             for (int y = 0; y < frameComponent.verticalSamplingFactor; y++) {
                 for (int x = 0; x < frameComponent.horizontalSamplingFactor; x++) {
                     Arrays.fill(zz, 0);
                     // page 104 of T.81
                     final int t = decode(is, huffmanDCTables[scanComponent.dcCodingTableSelector]);
                     int diff = receive(t, is);
                     diff = extend(diff, t);
                     zz[0] = preds[i] + diff;
                     preds[i] = zz[0];
 
                     // "Decode_AC_coefficients", figure F.13, page 106 of T.81
                     int k = 1;
                     while (true) {
                         final int rs = decode(is, huffmanACTables[scanComponent.acCodingTableSelector]);
                         final int ssss = rs & 0xf;
                         final int rrrr = rs >> 4;
                         final int r = rrrr;
 
                         if (ssss == 0) {
                             if (r != 15) {
                                 break;
                             }
                             k += 16;
                         } else {
                             k += r;
 
                             // "Decode_ZZ(k)", figure F.14, page 107 of T.81
                             zz[k] = receive(ssss, is);
                             zz[k] = extend(zz[k], ssss);
 
                             if (k == 63) {
                                 break;
                             }
                             k++;
                         }
                     }
 
                     final int shift = 1 << sofnSegment.precision - 1;
                     final int max = (1 << sofnSegment.precision) - 1;
 
                     final float[] scaledQuantizationTable = scaledQuantizationTables[frameComponent.quantTabDestSelector];
                     ZigZag.zigZagToBlock(zz, blockInt);
                     for (int j = 0; j < 64; j++) {
                         block[j] = blockInt[j] * scaledQuantizationTable[j];
                     }
                     Dct.inverseDct8x8(block);
 
                     int dstRowOffset = 8 * y * 8 * frameComponent.horizontalSamplingFactor + 8 * x;
                     int srcNext = 0;
                     for (int yy = 0; yy < 8; yy++) {
                         for (int xx = 0; xx < 8; xx++) {
                             float sample = block[srcNext++];
                             sample += shift;
                             final int result;
                             if (sample < 0) {
                                 result = 0;
                             } else if (sample > max) {
                                 result = max;
                             } else {
                                 result = fastRound(sample);
                             }
                             fullBlock.samples[dstRowOffset + xx] = result;
                         }
                         dstRowOffset += 8 * frameComponent.horizontalSamplingFactor;
                     }
                 }
             }
         }
     }
 
     private int receive(final int ssss, final JpegInputStream is) throws ImagingException {
         // "RECEIVE", section F.2.2.4, figure F.17, page 110 of T.81
         int i = 0;
         int v = 0;
         while (i != ssss) {
             i++;
             v = (v << 1) + is.nextBit();
         }
         return v;
     }
 
     private void rescaleMcu(final Block[] dataUnits, final int hSize, final int vSize, final Block[] ret) {
         for (int i = 0; i < dataUnits.length; i++) {
             final Block dataUnit = dataUnits[i];
             if (dataUnit.width == hSize && dataUnit.height == vSize) {
                 System.arraycopy(dataUnit.samples, 0, ret[i].samples, 0, hSize * vSize);
             } else {
                 final int hScale = hSize / dataUnit.width;
                 final int vScale = vSize / dataUnit.height;
                 if (hScale == 2 && vScale == 2) {
                     int srcRowOffset = 0;
                     int dstRowOffset = 0;
                     for (int y = 0; y < dataUnit.height; y++) {
                         for (int x = 0; x < hSize; x++) {
                             final int sample = dataUnit.samples[srcRowOffset + (x >> 1)];
                             ret[i].samples[dstRowOffset + x] = sample;
                             ret[i].samples[dstRowOffset + hSize + x] = sample;
                         }
                         srcRowOffset += dataUnit.width;
                         dstRowOffset += 2 * hSize;
                     }
                 } else {
                     // FIXME: optimize
                     int dstRowOffset = 0;
                     for (int y = 0; y < vSize; y++) {
                         for (int x = 0; x < hSize; x++) {
                             ret[i].samples[dstRowOffset + x] = dataUnit.samples[y / vScale * dataUnit.width + x / hScale];
                         }
                         dstRowOffset += hSize;
                     }
                 }
             }
         }
     }
 
     /**
      * Sets the decoder to treat incoming data as using the RGB color model. This extension to the JPEG specification is intended to support TIFF files that use
      * JPEG compression.
      */
     public void setTiffRgb() {
         useTiffRgb = true;
     }
 
     @Override
     public boolean visitSegment(final int marker, final byte[] markerBytes, final int segmentLength, final byte[] segmentLengthBytes, final byte[] segmentData)
             throws ImagingException, IOException {
         final int[] sofnSegments = { JpegConstants.SOF0_MARKER, JpegConstants.SOF1_MARKER, JpegConstants.SOF2_MARKER, JpegConstants.SOF3_MARKER,
                 JpegConstants.SOF5_MARKER, JpegConstants.SOF6_MARKER, JpegConstants.SOF7_MARKER, JpegConstants.SOF9_MARKER, JpegConstants.SOF10_MARKER,
                 JpegConstants.SOF11_MARKER, JpegConstants.SOF13_MARKER, JpegConstants.SOF14_MARKER, JpegConstants.SOF15_MARKER, };
 
         if (Arrays.binarySearch(sofnSegments, marker) >= 0) {
             if (marker != JpegConstants.SOF0_MARKER) {
                 throw new ImagingException("Only sequential, baseline JPEGs " + "are supported at the moment");
             }
             sofnSegment = new SofnSegment(marker, segmentData);
         } else if (marker == JpegConstants.DQT_MARKER) {
             final DqtSegment dqtSegment = new DqtSegment(marker, segmentData);
             for (final QuantizationTable table : dqtSegment.quantizationTables) {
                 if (0 > table.destinationIdentifier || table.destinationIdentifier >= quantizationTables.length) {
                     throw new ImagingException("Invalid quantization table identifier " + table.destinationIdentifier);
                 }
                 quantizationTables[table.destinationIdentifier] = table;
                 final int mSize = 64;
                 final int[] quantizationMatrixInt = Allocator.intArray(mSize);
                 ZigZag.zigZagToBlock(table.getElements(), quantizationMatrixInt);
                 final float[] quantizationMatrixFloat = Allocator.floatArray(mSize);
                 for (int j = 0; j < mSize; j++) {
                     quantizationMatrixFloat[j] = quantizationMatrixInt[j];
                 }
                 Dct.scaleDequantizationMatrix(quantizationMatrixFloat);
                 scaledQuantizationTables[table.destinationIdentifier] = quantizationMatrixFloat;
             }
         } else if (marker == JpegConstants.DHT_MARKER) {
             final DhtSegment dhtSegment = new DhtSegment(marker, segmentData);
             for (final HuffmanTable table : dhtSegment.huffmanTables) {
                 final DhtSegment.HuffmanTable[] tables;
                 if (table.tableClass == 0) {
                     tables = huffmanDCTables;
                 } else if (table.tableClass == 1) {
                     tables = huffmanACTables;
                 } else {
                     throw new ImagingException("Invalid huffman table class " + table.tableClass);
                 }
                 if (0 > table.destinationIdentifier || table.destinationIdentifier >= tables.length) {
                     throw new ImagingException("Invalid huffman table identifier " + table.destinationIdentifier);
                 }
                 tables[table.destinationIdentifier] = table;
             }
         }
         return true;
     }
 
     @Override
     public void visitSos(final int marker, final byte[] markerBytes, final byte[] imageData) {
         try (ByteArrayInputStream is = new ByteArrayInputStream(imageData)) {
             // read the scan header
             final int segmentLength = read2Bytes("segmentLength", is, "Not a Valid JPEG File", getByteOrder());
             final byte[] sosSegmentBytes = readBytes("SosSegment", is, segmentLength - 2, "Not a Valid JPEG File");
             sosSegment = new SosSegment(marker, sosSegmentBytes);
             // read the payload of the scan, this is the remainder of image data after the header
             // the payload contains the entropy-encoded segments (or ECS) divided by RST markers
             // or only one ECS if the entropy-encoded data is not divided by RST markers
             // length of payload = length of image data - length of data already read
             final int[] scanPayload = Allocator.intArray(imageData.length - segmentLength);
             int payloadReadCount = 0;
             while (payloadReadCount < scanPayload.length) {
                 scanPayload[payloadReadCount] = is.read();
                 payloadReadCount++;
             }
 
             int hMax = 0;
             int vMax = 0;
             for (int i = 0; i < sofnSegment.numberOfComponents; i++) {
                 hMax = Math.max(hMax, sofnSegment.getComponents(i).horizontalSamplingFactor);
                 vMax = Math.max(vMax, sofnSegment.getComponents(i).verticalSamplingFactor);
             }
             final int hSize = 8 * hMax;
             final int vSize = 8 * vMax;
 
             final int xMCUs = (sofnSegment.width + hSize - 1) / hSize;
             final int yMCUs = (sofnSegment.height + vSize - 1) / vSize;
             final Block[] mcu = allocateMcuMemory();
             final Block[] scaledMCU = Allocator.array(mcu.length, Block[]::new, Block.SHALLOW_SIZE);
             Arrays.setAll(scaledMCU, i -> new Block(hSize, vSize));
             final int[] preds = Allocator.intArray(sofnSegment.numberOfComponents);
             final ColorModel colorModel;
             final WritableRaster raster;
             Allocator.check(Integer.BYTES * sofnSegment.width * sofnSegment.height);
             switch (sofnSegment.numberOfComponents) {
             case 4:
                 // Special handling for the application-RGB case: TIFF files with
                 // JPEG compression can support an alpha channel. This extension
                 // to the JPEG standard is implemented by specifying a color model
                 // with a fourth channel for alpha.
                 if (useTiffRgb) {
                     colorModel = new DirectColorModel(32, 0x00ff0000, 0x0000ff00, 0x000000ff, 0xff000000);
                     raster = Raster.createPackedRaster(DataBuffer.TYPE_INT, sofnSegment.width, sofnSegment.height, BAND_MASK_ARGB, null);
                 } else {
                     colorModel = new DirectColorModel(24, 0x00ff0000, 0x0000ff00, 0x000000ff);
                     raster = Raster.createPackedRaster(DataBuffer.TYPE_INT, sofnSegment.width, sofnSegment.height, BAND_MASK_RGB, null);
                 }
 
                 break;
             case 3:
                 colorModel = new DirectColorModel(24, 0x00ff0000, 0x0000ff00, 0x000000ff);
                 raster = Raster.createPackedRaster(DataBuffer.TYPE_INT, sofnSegment.width, sofnSegment.height, new int[] { 0x00ff0000, 0x0000ff00, 0x000000ff },
                         null);
                 break;
             case 1:
                 colorModel = new DirectColorModel(24, 0x00ff0000, 0x0000ff00, 0x000000ff);
                 raster = Raster.createPackedRaster(DataBuffer.TYPE_INT, sofnSegment.width, sofnSegment.height, new int[] { 0x00ff0000, 0x0000ff00, 0x000000ff },
                         null);
                 // FIXME: why do images come out too bright with CS_GRAY?
                 // colorModel = new ComponentColorModel(
                 // ColorSpace.getInstance(ColorSpace.CS_GRAY), false, true,
                 // Transparency.OPAQUE, DataBuffer.TYPE_BYTE);
                 // raster = colorModel.createCompatibleWritableRaster(
                 // sofnSegment.width, sofnSegment.height);
                 break;
             default:
                 throw new ImagingException(sofnSegment.numberOfComponents + " components are invalid or unsupported");
             }
             final DataBuffer dataBuffer = raster.getDataBuffer();
 
             final JpegInputStream[] bitInputStreams = splitByRstMarkers(scanPayload);
             int bitInputStreamCount = 0;
             JpegInputStream bitInputStream = bitInputStreams[0];
 
             for (int y1 = 0; y1 < vSize * yMCUs; y1 += vSize) {
                 for (int x1 = 0; x1 < hSize * xMCUs; x1 += hSize) {
                     // Provide the next interval if an interval is read until it's end
                     // as long there are unread intervals available
                     if (!bitInputStream.hasNext()) {
                         bitInputStreamCount++;
                         if (bitInputStreamCount < bitInputStreams.length) {
                             bitInputStream = bitInputStreams[bitInputStreamCount];
                         }
                     }
 
                     readMcu(bitInputStream, preds, mcu);
                     rescaleMcu(mcu, hSize, vSize, scaledMCU);
                     int srcRowOffset = 0;
                     int dstRowOffset = y1 * sofnSegment.width + x1;
 
                     // The TIFF-RGB logic was adapted from the original x2,y2 loops
                     // but special handling was added for TIFF-JPEG RGB colorspace
                     // and conditional checks were reorganized for efficiency
                     if (useTiffRgb && (scaledMCU.length == 3 || scaledMCU.length == 4)) {
                         // The original (legacy) coding for the x2 and y2 loop was:
                         // for(y2 = 0; y2 < vSize && y1 + y2 < sofnSegment.height; y2++)
                         // for(x2 = 0; x2 < hSize && x1 + x2 < sofnSegment.width; x2++)
                         // Here, we pre-compute the limits of the loop to reduce the
                         // overhead for the loop conditional evaluation.
                         final int x2Limit;
                         if (x1 + hSize <= sofnSegment.width) {
                             x2Limit = hSize;
                         } else {
                             x2Limit = sofnSegment.width - x1;
                         }
                         final int y2Limit;
                         if (y1 + vSize <= sofnSegment.height) {
                             y2Limit = vSize;
                         } else {
                             y2Limit = sofnSegment.height - y1;
                         }
 
                         if (scaledMCU.length == 4) {
                             // RGBA colorspace
                             // Although conventional JPEGs don't include an alpha channel
                             // TIFF images that use JPEG encoding may do so. For example,
                             // we have seen this variation in some false-color satellite images
                             // from the U.S. National Weather Service. Ordinary JPEG files
                             // may include an APP14 marker of type Unknowm indicating that
                             // the scaledMCU.length of 3 should be interpreted as the RGB colorspace
                             // and the 4-channel variation is interpreted as CYMK. But TIFF files
                             // use their own tags to specify colorspace and do not include the APP14 marker.
                             for (int y2 = 0; y2 < y2Limit; y2++) {
                                 for (int x2 = 0; x2 < x2Limit; x2++) {
                                     final int r = scaledMCU[0].samples[srcRowOffset + x2];
                                     final int g = scaledMCU[1].samples[srcRowOffset + x2];
                                     final int b = scaledMCU[2].samples[srcRowOffset + x2];
                                     final int a = scaledMCU[3].samples[srcRowOffset + x2];
                                     final int rgb = a << 24 | r << 16 | g << 8 | b;
                                     dataBuffer.setElem(dstRowOffset + x2, rgb);
                                 }
                                 srcRowOffset += hSize;
                                 dstRowOffset += sofnSegment.width;
                             }
                         } else {
                             // scaledMCU.length == 3, standard RGB
                             for (int y2 = 0; y2 < y2Limit; y2++) {
                                 for (int x2 = 0; x2 < x2Limit; x2++) {
                                     final int r = scaledMCU[0].samples[srcRowOffset + x2];
                                     final int g = scaledMCU[1].samples[srcRowOffset + x2];
                                     final int b = scaledMCU[2].samples[srcRowOffset + x2];
                                     final int rgb = r << 16 | g << 8 | b;
                                     dataBuffer.setElem(dstRowOffset + x2, rgb);
                                 }
                                 srcRowOffset += hSize;
                                 dstRowOffset += sofnSegment.width;
                             }
                         }
                     } else {
                         for (int y2 = 0; y2 < vSize && y1 + y2 < sofnSegment.height; y2++) {
                             for (int x2 = 0; x2 < hSize && x1 + x2 < sofnSegment.width; x2++) {
                                 if (scaledMCU.length == 4) {
                                     final int c = scaledMCU[0].samples[srcRowOffset + x2];
                                     final int m = scaledMCU[1].samples[srcRowOffset + x2];
                                     final int y = scaledMCU[2].samples[srcRowOffset + x2];
                                     final int k = scaledMCU[3].samples[srcRowOffset + x2];
                                     final int rgb = ColorConversions.convertCmykToRgb(c, m, y, k);
                                     dataBuffer.setElem(dstRowOffset + x2, rgb);
                                 } else if (scaledMCU.length == 3) {
                                     final int y = scaledMCU[0].samples[srcRowOffset + x2];
                                     final int cb = scaledMCU[1].samples[srcRowOffset + x2];
                                     final int cr = scaledMCU[2].samples[srcRowOffset + x2];
                                     final int rgb = YCbCrConverter.convertYCbCrToRgb(y, cb, cr);
                                     dataBuffer.setElem(dstRowOffset + x2, rgb);
                                 } else if (mcu.length == 1) {
                                     final int y = scaledMCU[0].samples[srcRowOffset + x2];
                                     dataBuffer.setElem(dstRowOffset + x2, y << 16 | y << 8 | y);
                                 } else {
                                     throw new ImagingException("Unsupported JPEG with " + mcu.length + " components");
                                 }
                             }
                             srcRowOffset += hSize;
                             dstRowOffset += sofnSegment.width;
                         }
                     }
                 }
             }
             image = new BufferedImage(colorModel, raster, colorModel.isAlphaPremultiplied(), new Properties());
             // byte[] remainder = super.getStreamBytes(is);
             // for (int i = 0; i < remainder.length; i++)
             // {
             // System.out.println("" + i + " = " +
             // Integer.toHexString(remainder[i]));
             // }
         } catch (final ImagingException imageReadEx) {
             imageReadException = imageReadEx;
         } catch (final IOException ioEx) {
             ioException = ioEx;
         } catch (final RuntimeException ex) {
             // Corrupt images can throw NPE and IOOBE
             imageReadException = new ImagingException("Error parsing JPEG", ex);
         }
     }
 }