/*************************************************************************
 * Copyright 2009-2012 Eucalyptus Systems, 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; version 3 of the License.
 *
 * 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, see http://www.gnu.org/licenses/.
 *
 * Please contact Eucalyptus Systems, Inc., 6755 Hollister Ave., Goleta
 * CA 93117, USA or visit http://www.eucalyptus.com/licenses/ if you need
 * additional information or have any questions.
 *
 * This file may incorporate work covered under the following copyright
 * and permission notice:
 *
 *   Software License Agreement (BSD License)
 *
 *   Copyright (c) 2008, Regents of the University of California
 *   All rights reserved.
 *
 *   Redistribution and use of this software in source and binary forms,
 *   with or without modification, are permitted provided that the
 *   following conditions are met:
 *
 *     Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *
 *     Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer
 *     in the documentation and/or other materials provided with the
 *     distribution.
 *
 *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 *   FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 *   COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 *   INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 *   BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 *   LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 *   CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 *   LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
 *   ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 *   POSSIBILITY OF SUCH DAMAGE. USERS OF THIS SOFTWARE ACKNOWLEDGE
 *   THE POSSIBLE PRESENCE OF OTHER OPEN SOURCE LICENSED MATERIAL,
 *   COPYRIGHTED MATERIAL OR PATENTED MATERIAL IN THIS SOFTWARE,
 *   AND IF ANY SUCH MATERIAL IS DISCOVERED THE PARTY DISCOVERING
 *   IT MAY INFORM DR. RICH WOLSKI AT THE UNIVERSITY OF CALIFORNIA,
 *   SANTA BARBARA WHO WILL THEN ASCERTAIN THE MOST APPROPRIATE REMEDY,
 *   WHICH IN THE REGENTS' DISCRETION MAY INCLUDE, WITHOUT LIMITATION,
 *   REPLACEMENT OF THE CODE SO IDENTIFIED, LICENSING OF THE CODE SO
 *   IDENTIFIED, OR WITHDRAWAL OF THE CODE CAPABILITY TO THE EXTENT
 *   NEEDED TO COMPLY WITH ANY SUCH LICENSES OR RIGHTS.
 ************************************************************************/

package com.eucalyptus.storage.common;

import java.io.ByteArrayOutputStream;
import java.io.RandomAccessFile;
import java.util.zip.GZIPOutputStream;

import org.apache.log4j.Logger;
import org.jboss.netty.buffer.ChannelBuffers;
import org.jboss.netty.handler.stream.ChunkedInput;

import edu.ucsb.eucalyptus.constants.IsData;

public class CompressedChunkedFile implements ChunkedInput, IsData {
  private Logger LOG = Logger.getLogger(CompressedChunkedFile.class);
  private RandomAccessFile file;
  private long offset;
  private int CHUNK_SIZE = 8192;
  private long fileLength;

  public CompressedChunkedFile(RandomAccessFile file, long fileLength) {
    this.file = file;
    this.offset = 0;
    this.fileLength = fileLength;
  }

  public CompressedChunkedFile(RandomAccessFile file, long start, long end, int chunkSize) {
    this.file = file;
    this.offset = start;
    this.fileLength = end;
    CHUNK_SIZE = chunkSize;
  }

  @Override
  public void close() throws Exception {
    file.close();
  }

  @Override
  public boolean hasNextChunk() throws Exception {
    return offset < fileLength && file.getChannel().isOpen();
  }

  @Override
  public Object nextChunk() throws Exception {
    long offset = this.offset;
    if (offset >= fileLength) {
      return null;
    }
    int chunkSize = (int) Math.min(CHUNK_SIZE, fileLength - offset);
    byte[] chunk = new byte[chunkSize];
    file.readFully(chunk);
    this.offset = offset + chunkSize;
    ByteArrayOutputStream out = new ByteArrayOutputStream();
    GZIPOutputStream zip = new GZIPOutputStream(out);
    zip.write(chunk);
    zip.close();
    return ChannelBuffers.wrappedBuffer(out.toByteArray());
  }

  @Override
  public boolean isEndOfInput() throws Exception {
    return !hasNextChunk();
  }
}