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

/*

 * Copyright (c) 2005 INRIA

 *

 * 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

 *

 * Author: Mathieu Lacage <mathieu.lacage@sophia.inria.fr>

 */

#ifndef WIFI_MAC_QUEUE_H

#define WIFI_MAC_QUEUE_H

#include <deque>

#include <utility>

#include "ns3/packet.h"

#include "ns3/nstime.h"

#include "wifi-mac-header.h"

namespace ns3 {

/**

 * \brief a 802.11e-specific queue.

 *

 * This queue implements what is needed for the 802.11e standard

 * Specifically, it refers to 802.11e/D9, section 9.9.1.6, paragraph 6.

 *

 * When a packet is received by the MAC, to be sent to the PHY, 

 * it is queued in the internal queue after being tagged by the 

 * current time.

 *

 * When a packet is dequeued, the queue checks its timestamp 

 * to verify whether or not it should be dropped. If 

 * dot11EDCATableMSDULifetime has elapsed, it is dropped.

 * Otherwise, it is returned to the caller.

 */

class WifiMacQueue {

public:

  WifiMacQueue ();

  ~WifiMacQueue ();

  void SetMaxSize (uint32_t maxSize);

  void SetMaxDelay (Time delay);

  void Enqueue (Ptr<const Packet> packet, WifiMacHeader const &hdr);

  Ptr<const Packet> Dequeue (WifiMacHeader *hdr);

  void Flush (void);

  bool IsEmpty (void);

  uint32_t GetSize (void);

private:

  void Cleanup (void);

  struct Item {

    Item (Ptr<const Packet> packet, 

          WifiMacHeader const&hdr, 

          Time tstamp);

    Ptr<const Packet> packet;

    WifiMacHeader hdr;

    Time tstamp;

  };

  typedef std::deque<struct Item> PacketQueue;

  typedef std::deque<struct Item>::reverse_iterator PacketQueueRI;

  typedef std::deque<struct Item>::iterator PacketQueueI;

  PacketQueue m_queue;

  uint32_t m_size;

  uint32_t m_maxSize;

  Time m_maxDelay;

};

} // namespace ns3

#endif /* WIFI_MAC_QUEUE_H */