/* Copyright (c) 2012 Jesper Öqvist <jesper@llbit.se>
 *
 * This file is part of Chunky.
 *
 * Chunky 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 3 of the License, or
 * (at your option) any later version.
 *
 * Chunky 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 Chunky.  If not, see <http://www.gnu.org/licenses/>.
 */
package se.llbit.png;

import java.io.DataOutputStream;
import java.io.IOException;

/**
 * A PNG chunk
 *
 * @author Jesper Öqvist <jesper@llbit.se>
 */
public abstract class PngChunk {

  /**
   * Write the chunk to an output stream.
   *
   * @param out the stream to write the chunk to.
   * @throws IOException
   */
  public void writeChunk(DataOutputStream out) throws IOException {
    out.writeInt(getChunkLength());
    out.writeInt(getChunkType());
    if (getChunkLength() > 0) {
      writeChunkData(out);
    }
    out.writeInt(getChunkCRC());
  }

  protected abstract void writeChunkData(DataOutputStream out) throws IOException;

  /**
   * @return The chunk length, in bytes
   */
  public abstract int getChunkLength();

  /**
   * @return The chunk type identifier
   */
  public abstract int getChunkType();

  /**
   * @return The chunk CRC
   */
  public abstract int getChunkCRC();

}