GElementID.h

/***************************************************************************
 *   Copyright (C) 2003-2004 by Raphael Langerhorst                        *
 *   raphael-langerhorst@gmx.at                                            *
 *                                                                         *
 *   Permission is hereby granted, free of charge, to any person obtaining *
 *   a copy of this software and associated documentation files (the       *
 *   "Software"), to deal in the Software without restriction, including   *
 *   without limitation the rights to use, copy, modify, merge, publish,   *
 *   distribute, sublicense, and/or sell copies of the Software, and to    *
 *   permit persons to whom the Software is furnished to do so, subject to *
 *   the following conditions:                                             *
 *                                                                         *
 *   The above copyright notice and this permission notice shall be        *
 *   included in all copies or substantial portions of the Software.       *
 *                                                                         *
 *   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,       *
 *   EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF    *
 *   MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*
 *   IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR     *
 *   OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, *
 *   ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR *
 *   OTHER DEALINGS IN THE SOFTWARE.                                       *
 ***************************************************************************/

#ifndef GELEMENTIDH
#define GELEMENTIDH

//needed prototype for friend declarations
template<class T>
class QValueListNode;

namespace GCS
{

//will be defined in the implementation
class IDRange;

class GElementID
{  
  private:
    
    static IDRange FreeIDs;
    
  public:
    
    static GElementID getNextFreeID();
    
    static void initFreeIDs(unsigned long low, unsigned long high);
    
  private:
  
    unsigned long ID;

  private:
    GElementID()
    : ID(0)
    {}
    
  public:
  
    GElementID(unsigned long ID) : ID(ID) {}

    GElementID(const GElementID& original) : ID(original.ID) {}

    unsigned long getID() const
    {
      return this->ID;
    }

    bool operator==(const GElementID& id) const
    {
      if (id.ID == this->ID)
        return true;
      return false;
    }
    
    bool operator!=(const GElementID& id) const
    {
      if (id.ID != this->ID)
        return true;
      return false;
    }
    
    //this is a workaround because QValueListNode needs
    //a default constructor;
    //
    //this constructor is declared private in GElementID
    //and made only available to this class
    //
    //note: QValueListNode is used by QValueList
    
    friend class QValueListNode<GElementID>;
};

}

#endif

---