/FileExtraction/Java_unseen/dlitz_resin/modules/resin/src/com/caucho/remote/websocket/FrameInputStream.java
/*
 * Copyright (c) 1998-2011 Caucho Technology -- all rights reserved
 *
 * This file is part of Resin(R) Open Source
 *
 * Each copy or derived work must preserve the copyright notice and this
 * notice unmodified.
 *
 * Resin Open Source 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.
 *
 * Resin Open Source 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, or any warranty
 * of NON-INFRINGEMENT.  See the GNU General Public License for more
 * details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Resin Open Source; if not, write to the
 *
 *   Free Software Foundation, Inc.
 *   59 Temple Place, Suite 330
 *   Boston, MA 02111-1307  USA
 *
 * @author Scott Ferguson
 */

package com.caucho.remote.websocket;

import java.io.IOException;
import java.io.InputStream;

/**
 * WebSocketInputStream reads a single WebSocket packet.
 *
 * <code><pre>
 * +-+------+---------+-+---------+
 * |F|xxx(3)|opcode(4)|R|len(7)   |
 * +-+------+---------+-+---------+
 * 
 * OPCODES
 *   0 - cont
 *   1 - close
 *   2 - ping
 *   3 - pong
 *   4 - text
 *   5 - binary
 * </pre></code>
 */
abstract public class FrameInputStream extends InputStream 
  implements WebSocketConstants
{
  abstract public void init(InputStream is);
  
  abstract public int getOpcode();

  abstract public long getLength();
  
  abstract public boolean isFinal();

  public boolean readFrameHeader()
    throws IOException
  {
    long length = getLength();
    
    if (length > 0)
      skip(length);

    return readFrameHeaderImpl();
  }

  abstract protected boolean readFrameHeaderImpl()
    throws IOException;

  public void skipToFrameEnd()
    throws IOException
  {
    while (getLength() > 0 && ! isFinal()) {
      skip(getLength());
    }
  }
}
