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

/*

 * Copyright (c) 2005, 2009 INRIA

 * Copyright (c) 2009 MIRKO BANCHI

 *

 * 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>

 * Author: Mirko Banchi <mk.banchi@gmail.com>

 */

#ifndef WIFI_MAC_QUEUE_H

#define WIFI_MAC_QUEUE_H

#include <list>

#include <utility>

#include "ns3/packet.h"

#include "ns3/nstime.h"

#include "ns3/object.h"

#include "wifi-mac-header.h"

namespace ns3 {

class WifiMacParameters;

/**

 * \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 Object

{

public:

  static TypeId GetTypeId (void);

  WifiMacQueue ();

  ~WifiMacQueue ();

  void SetMaxSize (uint32_t maxSize);

  void SetMaxDelay (Time delay);

  uint32_t GetMaxSize (void) const;

  Time GetMaxDelay (void) const;

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

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

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

  /**

   * Searchs and returns, if is present in this queue, first packet having 

   * address indicated by <i>type</i> equals to <i>addr</i>, and tid 

   * equals to <i>tid</i>. This method removes the packet from this queue. 

   * Is typically used by ns3::EdcaTxopN in order to perform correct MSDU 

   * aggregation (A-MSDU).

   */

  Ptr<const Packet> DequeueByTidAndAddress (WifiMacHeader *hdr,

                                            uint8_t tid, 

                                            WifiMacHeader::AddressType type,

                                            Mac48Address addr);

  /**

   * Searchs and returns, if is present in this queue, first packet having

   * address indicated by <i>type</i> equals to <i>addr</i>, and tid 

   * equals to <i>tid</i>. This method doesn't remove the packet from this queue.

   * Is typically used by ns3::EdcaTxopN in order to perform correct MSDU

   * aggregation (A-MSDU).

   */

  Ptr<const Packet> PeekByTidAndAddress (WifiMacHeader *hdr,

                                         uint8_t tid,

                                         WifiMacHeader::AddressType type,

                                         Mac48Address addr);

  /**

   * If exists, removes <i>packet</i> from queue and returns true. Otherwise it

   * takes no effects and return false. Deletion of the packet is

   * performed in linear time (O(n)).  

   */

  bool Remove (Ptr<const Packet> packet);

  void Flush (void);

  bool IsEmpty (void);

  uint32_t GetSize (void);

private:

  struct Item;

  typedef std::list<struct Item> PacketQueue;

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

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

  void Cleanup (void);

  Mac48Address GetAddressForPacket (enum WifiMacHeader::AddressType type, PacketQueueI);

  struct Item {

    Item (Ptr<const Packet> packet, 

          const WifiMacHeader &hdr, 

          Time tstamp);

    Ptr<const Packet> packet;

    WifiMacHeader hdr;

    Time tstamp;

  };

  PacketQueue m_queue;

  WifiMacParameters *m_parameters;

  uint32_t m_size;

  uint32_t m_maxSize;

  Time m_maxDelay;

};

} // namespace ns3

#endif /* WIFI_MAC_QUEUE_H */