tqueue.h

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/*
 *  tqueue.h - A queue of time-based events for animation.
 *
 *  Copyright (C) 2000-2001  The Exult Team
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  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.
 */

#ifndef TQUEUE_H
#define TQUEUE_H  1


#include <vector>
#include <list>

#include "exult_types.h"



/*
 *  An interface for entries in the queue:
 */
class Time_sensitive
  {
  int queue_cnt;      // # of entries for this in queue.
  bool always;      // Always do this, even if paused.
public:
  friend class Time_queue;
  Time_sensitive() : queue_cnt(0), always(false)
    {  }
  virtual ~Time_sensitive();
  int in_queue()
    { return queue_cnt > 0; }
  void set_always(bool tf)  // Should be called before placing in
          //   queue.
    { always = tf; }
  virtual void handle_event(unsigned long curtime, long udata) = 0;
  };

class Time_queue;

/*
 *  A queue entry:
 */
class Queue_entry
  {
  public:
  // Queue_entry *next, *prev;  // Next, prev. in queue.
  Time_sensitive *handler;  // Object to activate.
  long udata;     // Data to pass to handler.
  uint32 time;      // Time when this is due.
  inline void set(uint32 t, Time_sensitive *h, long ud)
    {
    time = t;
    handler = h;
    udata = ud;
    }
  };

bool  operator <(const Queue_entry &q1,const Queue_entry &q2);

/*
 *  Time-based queue.  The entries are kept sorted in increasing order
 *  by time.
 */
class Time_queue
  {
  typedef std::list<Queue_entry>  Temporal_sequence;
  Temporal_sequence data;
  uint32 pause_time;    // Time when paused.
  int paused;     // Count of calls to 'pause()'.

  // Activate head + any others due.
  void activate0(uint32 curtime);
  void activate_always(uint32 curtime);
public:
  friend class Time_queue_iterator;
  // Time_queue() : head(0), free_entries(0)
  Time_queue() : pause_time(0), paused(0)
    {  }
  void clear();     // Remove all entries.
          // Add an entry.
  void add(uint32 t, Time_sensitive *obj, long ud);
          // Remove object's entry.
  int remove(Time_sensitive *obj);
  int remove(Time_sensitive *obj, long udata);
  int find(Time_sensitive *obj);  // Find an entry.
          // Find delay when obj. is due.
  long find_delay(Time_sensitive *obj, uint32 curtime);
          // Activate entries that are 'due'.
  inline void activate(uint32 curtime)
    {
    // if (head && !(curtime < head->time))
    if (paused)
      activate_always(curtime);
    else if (data.size() && !(curtime < data.front().time))
      activate0(curtime);
    }
  void pause(uint32 curtime)  // Game paused.
    {
    if (!paused++)
      pause_time = curtime;
    }
  void resume(uint32 curtime);
  };


class Time_queue_iterator
  {
  Time_queue::Temporal_sequence::iterator iter;
  Time_queue *tqueue;
  Time_sensitive *this_obj; // Only return entries for this obj.
public:
  Time_queue_iterator(Time_queue *tq, Time_sensitive *obj)
      : iter(tq->data.begin()), tqueue(tq), this_obj(obj)
    {  }
  int operator()(Time_sensitive *& obj, long& data);
  };

#endif  /* TQUEUE_H */

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