objlist.h

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/*
Copyright (C) 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 OBJLIST_H
#define OBJLIST_H

#include "shapeid.h"

template<class T>
class T_Object_iterator;
template<class T, class L>
class T_Flat_object_iterator;
template<class T, class L>
class T_Object_iterator_backwards;

/*
 *  A list of objects chained together with the 'next' and 'prev'
 *  fields:
 */
template<class T>
class T_Object_list
  {
  friend class T_Object_iterator<T>;
  friend class T_Flat_object_iterator<T, class L>;
  friend class T_Object_iterator_backwards<T, class L>;

  T first;    // ->first in (circular) chain.
  unsigned short iter_count;  // # of iterators.
public:
  T_Object_list(T f = 0) : first(f), iter_count(0)
    {  }
          // Delete the chain.
  ~T_Object_list()
    {
    if (!first)
      return;
    T objects = first;
    T obj;
    do
      {
      obj = objects;
      objects = obj->next;
      delete obj;
      }
    while (obj != first);
    }
          // Report iterator problem.
  void report_problem() const
    {
      std::cerr << "Danger! Danger! Object list modified while being iterated." << std::endl;
      std::cerr.flush();
    }
  int is_empty() const
    { return first == 0; }
  void add_iterator()
    { iter_count++; }
  void remove_iterator()
    { iter_count--; }
  T get_first() const
    { return first; }
          // Insert at head of chain.
  void insert(T nobj)
    {
    if (iter_count)
      report_problem();
    if (!first)   // First one.
      nobj->next = nobj->prev = nobj;
    else
      {
      nobj->next = first;
      nobj->prev = first->prev;
      first->prev->next = nobj;
      first->prev = nobj;
      }
    first = nobj;
    }
          // Insert before given obj.
  void insert_before(T nobj, T before)
    {
    if (iter_count)
      report_problem();
    nobj->next = before;
    nobj->prev = before->prev;
    before->prev->next = nobj;
    before->prev = nobj;
    first = before == first ? nobj : first;
    }
          // Append.
  void append(T nobj)
    { insert(nobj); first = nobj->next; }
  void remove(T dobj)
    {
    if (iter_count)
      report_problem();
    if (dobj == first)
      first = dobj->next != first ? dobj->next : 0;
    dobj->next->prev = dobj->prev;
    dobj->prev->next = dobj->next;
    }
  };


class Game_object;
typedef T_Object_list<Game_object *> Object_list;


#endif

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