/* -*- 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 EVENT_ID_H

#define EVENT_ID_H

#include <stdint.h>

#include "ns3/ptr.h"

#include "event-impl.h"

namespace ns3 {

class EventImpl;

/**

 * \ingroup simulator

 * \brief an identifier for simulation events.

 *

 * Each EventId identifies a unique event scheduled with one

 * of the many Simulator::Schedule methods. This EventId can

 * be used to Cancel or Remove events after they are scheduled

 * with Simulator::Cancel or Simulator::Remove.

 *

 * The important thing to remember about this class is that

 * every variable of this type is _always_ in a valid state, 

 * even when it has not been assigned an EventId coming from a Schedule

 * method: calling Cancel, IsRunning, IsExpired or passing around

 * instances of this object will not result in crashes or memory leaks.

 */

class EventId {

public:

  EventId ();

  // internal.

  EventId (const Ptr<EventImpl> &impl, uint64_t ts, uint32_t uid);

  /**

   * This method is syntactic sugar for the ns3::Simulator::cancel

   * method.

   */

  void Cancel (void);

  /**

   * This method is syntactic sugar for the ns3::Simulator::isExpired

   * method.

   * \returns true if the event has expired, false otherwise.

   */

  bool IsExpired (void) const;

  /**

   * This method is syntactic sugar for the ns3::Simulator::isExpired

   * method.

   * \returns true if the event has not expired, false otherwise.

   */

  bool IsRunning (void) const;

public:

  /* The following methods are semi-private

   * they are supposed to be invoked only by

   * subclasses of the Scheduler base class.

   */

  EventImpl *PeekEventImpl (void) const;

  uint64_t GetTs (void) const;

  uint32_t GetUid (void) const;

private:

  friend bool operator == (const EventId &a, const EventId &b);

  Ptr<EventImpl> m_eventImpl;

  uint64_t m_ts;

  uint32_t m_uid;

};

bool operator == (const EventId &a, const EventId &b);

bool operator != (const EventId &a, const EventId &b);

}; // namespace ns3

#endif /* EVENT_ID_H */