queue.h

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/* -*- 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
 */

// The queue base class has a limit on its size, in terms of number of
// packets or number of bytes depending on the operating mode.
// The base class implements tracing and basic statistics calculations.

#ifndef QUEUE_H
#define QUEUE_H

#include "ns3/packet.h"
#include "ns3/object.h"
#include "ns3/traced-callback.h"
#include "ns3/net-device.h"
#include "ns3/traced-value.h"

namespace ns3 {

class Queue : public Object
{
public:
  static TypeId GetTypeId (void);

  Queue ();
  virtual ~Queue ();

  bool IsEmpty (void) const;
  bool Enqueue (Ptr<QueueItem> item);
  Ptr<QueueItem> Dequeue (void);
  Ptr<const QueueItem> Peek (void) const;

  void DequeueAll (void);
  uint32_t GetNPackets (void) const;
  uint32_t GetNBytes (void) const;

  uint32_t GetTotalReceivedBytes (void) const;
  uint32_t GetTotalReceivedPackets (void) const;
  uint32_t GetTotalDroppedBytes (void) const;
  uint32_t GetTotalDroppedPackets (void) const;
  void ResetStatistics (void);

  enum QueueMode
  {
    QUEUE_MODE_PACKETS,     
    QUEUE_MODE_BYTES,       
  };

  void SetMode (Queue::QueueMode mode);

  Queue::QueueMode GetMode (void) const;

  void SetMaxPackets (uint32_t maxPackets);

  uint32_t GetMaxPackets (void) const;

  void SetMaxBytes (uint32_t maxBytes);

  uint32_t GetMaxBytes (void) const;

#if 0
  // average calculation requires keeping around
  // a buffer with the date of arrival of past received packets
  // which are within the average window
  // so, it is quite costly to do it all the time.
  // Hence, it is disabled by default and must be explicitely
  // enabled with this method which specifies the size
  // of the average window in time units.
  void EnableRunningAverage (Time averageWindow);
  void DisableRunningAverage (void);
  // average
  double GetQueueSizeAverage (void);
  double GetReceivedBytesPerSecondAverage (void);
  double GetReceivedPacketsPerSecondAverage (void);
  double GetDroppedBytesPerSecondAverage (void);
  double GetDroppedPacketsPerSecondAverage (void);
  // variance
  double GetQueueSizeVariance (void);
  double GetReceivedBytesPerSecondVariance (void);
  double GetReceivedPacketsPerSecondVariance (void);
  double GetDroppedBytesPerSecondVariance (void);
  double GetDroppedPacketsPerSecondVariance (void);
#endif

protected:
  void Drop (Ptr<Packet> p);

private:
  virtual bool DoEnqueue (Ptr<QueueItem> item) = 0;
  virtual Ptr<QueueItem> DoDequeue (void) = 0;
  virtual Ptr<const QueueItem> DoPeek (void) const = 0;

  TracedCallback<Ptr<const Packet> > m_traceEnqueue;
  TracedCallback<Ptr<const Packet> > m_traceDequeue;
  TracedCallback<Ptr<const Packet> > m_traceDrop;

  TracedValue<uint32_t> m_nBytes;   
  uint32_t m_nTotalReceivedBytes;   
  TracedValue<uint32_t> m_nPackets; 
  uint32_t m_nTotalReceivedPackets; 
  uint32_t m_nTotalDroppedBytes;    
  uint32_t m_nTotalDroppedPackets;  

  uint32_t m_maxPackets;              
  uint32_t m_maxBytes;                
  QueueMode m_mode;                   
};

} // namespace ns3

#endif /* QUEUE_H */