/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */

/*

 * Copyright (c) 2007 University of Washington

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License version 2 as

 * published by the Free Software Foundation;

 *

 * 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

 */

#ifndef DROPTAIL_H

#define DROPTAIL_H

#include <queue>

#include "ns3/packet.h"

#include "ns3/queue.h"

namespace ns3 {

class TraceContainer;

/**

 * \ingroup queue

 *

 * \brief A FIFO packet queue that drops tail-end packets on overflow

 */

class DropTailQueue : public Queue {

public:

  static TypeId GetTypeId (void);

  /**

   * \brief DropTailQueue Constructor

   *

   * Creates a droptail queue with a maximum size of 100 packets by default

   */

  DropTailQueue ();

  virtual ~DropTailQueue();

  /**

   * Enumeration of the modes supported in the class.

   *

   */

  enum Mode {

    ILLEGAL,     /**< Mode not set */

    PACKETS,     /**< Use number of packets for maximum queue size */

    BYTES,       /**< Use number of bytes for maximum queue size */  

  };

  /**

   * Set the operating mode of this device.

   *

   * \param mode The operating mode of this device.

   *

   */

  void SetMode (DropTailQueue::Mode mode);

  /**

   * Get the encapsulation mode of this device.

   *

   * \returns The encapsulation mode of this device.

   */

  DropTailQueue::Mode  GetMode (void);

private:

  virtual bool DoEnqueue (Ptr<Packet> p);

  virtual Ptr<Packet> DoDequeue (void);

  virtual Ptr<const Packet> DoPeek (void) const;

  std::queue<Ptr<Packet> > m_packets;

  uint32_t m_maxPackets;

  uint32_t m_maxBytes;

  uint32_t m_bytesInQueue;

  Mode     m_mode;

};

}; // namespace ns3

#endif /* DROPTAIL_H */