/*
 * 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
 *
 * Authors: Mathieu Lacage <mathieu.lacage@sophia.inria.fr>
 *          Mirko Banchi <mk.banchi@gmail.com>
 */

#ifndef MAC_TX_MIDDLE_H
#define MAC_TX_MIDDLE_H

#include "ns3/simple-ref-count.h"

#include <map>

namespace ns3
{

class WifiMacHeader;
class Mac48Address;

/**
 * \ingroup wifi
 *
 * Handles sequence numbering of IEEE 802.11 data frames
 */
class MacTxMiddle : public SimpleRefCount<MacTxMiddle>
{
  public:
    MacTxMiddle();
    ~MacTxMiddle();

    /**
     * Return the next sequence number for the given header.
     *
     * \param hdr Wi-Fi header
     * \return the next sequence number
     */
    uint16_t GetNextSequenceNumberFor(const WifiMacHeader* hdr);
    /**
     * Return the next sequence number for the Traffic ID and destination, but do not pick it (i.e.
     * the current sequence number remains unchanged). This functions is used for A-MPDU
     * aggregation.
     *
     * \param hdr Wi-Fi header
     * \return the next sequence number
     */
    uint16_t PeekNextSequenceNumberFor(const WifiMacHeader* hdr);
    /**
     * Return the next sequence number for the Traffic ID and destination.
     *
     * \param tid Traffic ID
     * \param addr destination address
     * \return the next sequence number
     */
    uint16_t GetNextSeqNumberByTidAndAddress(uint8_t tid, Mac48Address addr) const;
    /**
     * Set the sequence number of the given MAC header as the next sequence
     * number for the Traffic ID and destination of the given MAC header.
     *
     * \param hdr the given MAC header
     */
    void SetSequenceNumberFor(const WifiMacHeader* hdr);

  private:
    std::map<Mac48Address, uint16_t*> m_qosSequences; ///< QOS sequences
    uint16_t m_sequence;                              ///< current sequence number
};

} // namespace ns3

#endif /* MAC_TX_MIDDLE_H */
