//
// JPEGCodec.java
//

/*
OME Bio-Formats package for reading and converting biological file formats.
Copyright (C) 2005-@year@ UW-Madison LOCI and Glencoe Software, Inc.

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/

package loci.formats.codec;

import java.awt.image.BufferedImage;
import java.io.BufferedInputStream;
import java.io.ByteArrayOutputStream;
import java.io.DataInputStream;
import java.io.EOFException;
import java.io.IOException;

import javax.imageio.ImageIO;

import loci.common.RandomAccessInputStream;
import loci.formats.FormatException;
import loci.formats.gui.AWTImageTools;

/**
 * This class implements JPEG compression and decompression.
 *
 * <dl><dt><b>Source code:</b></dt>
 * <dd><a href="http://trac.openmicroscopy.org.uk/ome/browser/bioformats.git/components/bio-formats/src/loci/formats/codec/JPEGCodec.java">Trac</a>,
 * <a href="http://git.openmicroscopy.org/?p=bioformats.git;a=blob;f=components/bio-formats/src/loci/formats/codec/JPEGCodec.java;hb=HEAD">Gitweb</a></dd></dl>
 */
public class JPEGCodec extends BaseCodec {

  /**
   * The CodecOptions parameter should have the following fields set:
   *  {@link CodecOptions#width width}
   *  {@link CodecOptions#height height}
   *  {@link CodecOptions#channels channels}
   *  {@link CodecOptions#bitsPerSample bitsPerSample}
   *  {@link CodecOptions#interleaved interleaved}
   *  {@link CodecOptions#littleEndian littleEndian}
   *  {@link CodecOptions#signed signed}
   *
   * @see Codec#compress(byte[], CodecOptions)
   */
  public byte[] compress(byte[] data, CodecOptions options)
    throws FormatException
  {
    if (data == null || data.length == 0) return data;
    if (options == null) options = CodecOptions.getDefaultOptions();

    if (options.bitsPerSample > 8) {
      throw new FormatException("> 8 bit data cannot be compressed with JPEG.");
    }

    ByteArrayOutputStream out = new ByteArrayOutputStream();
    BufferedImage img = AWTImageTools.makeImage(data, options.width,
      options.height, options.channels, options.interleaved,
      options.bitsPerSample / 8, false, options.littleEndian, options.signed);

    try {
      ImageIO.write(img, "jpeg", out);
    }
    catch (IOException e) {
      throw new FormatException("Could not write JPEG data", e);
    }
    return out.toByteArray();
  }

  /**
   * The CodecOptions parameter should have the following fields set:
   *  {@link CodecOptions#interleaved interleaved}
   *  {@link CodecOptions#littleEndian littleEndian}
   *
   * @see Codec#decompress(RandomAccessInputStream, CodecOptions)
   */
  public byte[] decompress(RandomAccessInputStream in, CodecOptions options)
    throws FormatException, IOException
  {
    BufferedImage b;
    long fp = in.getFilePointer();
    try {
      try {
        while (in.read() != (byte) 0xff || in.read() != (byte) 0xd8);
        in.seek(in.getFilePointer() - 2);
      }
      catch (EOFException e) {
        in.seek(fp);
      }

      b = ImageIO.read(new BufferedInputStream(new DataInputStream(in), 8192));
    }
    catch (IOException exc) {
      // probably a lossless JPEG; delegate to LosslessJPEGCodec
      in.seek(fp);
      return new LosslessJPEGCodec().decompress(in, options);
    }

    if (options == null) options = CodecOptions.getDefaultOptions();

    byte[][] buf = AWTImageTools.getPixelBytes(b, options.littleEndian);
    byte[] rtn = new byte[buf.length * buf[0].length];
    if (buf.length == 1) rtn = buf[0];
    else {
      if (options.interleaved) {
        int next = 0;
        for (int i=0; i<buf[0].length; i++) {
          for (int j=0; j<buf.length; j++) {
            rtn[next++] = buf[j][i];
          }
        }
      }
      else {
        for (int i=0; i<buf.length; i++) {
          System.arraycopy(buf[i], 0, rtn, i*buf[0].length, buf[i].length);
        }
      }
    }
    return rtn;
  }
}