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

/*

 * Copyright (c) 2011 Centre Tecnologic de Telecomunicacions de Catalunya (CTTC)

 *

 * 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: Manuel Requena <manuel.requena@cttc.es>

 */

#ifndef LTE_RLC_UM_H

#define LTE_RLC_UM_H

#include "ns3/lte-rlc-sequence-number.h"

#include "ns3/lte-rlc.h"

#include <map>

namespace ns3 {

/**

 * LTE RLC Unacknowledged Mode (UM), see 3GPP TS 36.322

 */

class LteRlcUm : public LteRlc

{

public:

  LteRlcUm ();

  virtual ~LteRlcUm ();

  static TypeId GetTypeId (void);

  /**

   * RLC SAP

   */

  virtual void DoTransmitPdcpPdu (Ptr<Packet> p);

  /**

   * MAC SAP

   */

  virtual void DoNotifyHarqDeliveryFailure ();

  virtual void DoReceivePdu (Ptr<Packet> p);

  void Start ();

private:

  void ExpireReorderingTimer (void);

  void ExpireRbsTimer (void);

  bool IsInsideReorderingWindow (SequenceNumber10 seqNumber);

  void ReassembleOutsideWindow (void);

  void ReassembleSnLessThan (SequenceNumber10 seqNumber);

  void ReassembleAndDeliver (Ptr<Packet> packet);

  void DoReportBufferStatus ();

private:

  uint32_t m_txBufferSize;

  std::vector < Ptr<Packet> > m_txBuffer;       // Transmission buffer

  std::map <uint16_t, Ptr<Packet> > m_rxBuffer; // Reception buffer

  std::vector < Ptr<Packet> > m_reasBuffer;     // Reassembling buffer

  std::list < Ptr<Packet> > m_sdusBuffer;       // List of SDUs in a packet

  /**

   * State variables. See section 7.1 in TS 36.322

   */

  SequenceNumber10 m_sequenceNumber; // VT(US)

  SequenceNumber10 m_vrUr;           // VR(UR)

  SequenceNumber10 m_vrUx;           // VR(UX)

  SequenceNumber10 m_vrUh;           // VR(UH)

  /**

   * Constants. See section 7.2 in TS 36.322

   */

  uint16_t m_windowSize;

  /**

   * Timers. See section 7.3 in TS 36.322

   */

  EventId m_reorderingTimer;

  EventId m_rbsTimer;

  /**

   * Reassembling state

   */

  typedef enum { NONE            = 0,

                 WAITING_S0_FULL = 1,

                 WAITING_SI_SF   = 2 } ReassemblingState_t;

  ReassemblingState_t m_reassemblingState;

  Ptr<Packet> m_keepS0;

  /**

   * Expected Sequence Number

   */

  SequenceNumber10 m_expectedSeqNumber;

};

} // namespace ns3

#endif // LTE_RLC_UM_H