singleton.h

/***************************************************************************
 *   Copyright (C) 2005-2008 by the FIFE team                              *
 *   http://www.fifengine.de                                               *
 *   This file is part of FIFE.                                            *
 *                                                                         *
 *   FIFE is free software; you can redistribute it and/or                 *
 *   modify it under the terms of the GNU Lesser General Public            *
 *   License as published by the Free Software Foundation; either          *
 *   version 2.1 of the License, or (at your option) any later version.    *
 *                                                                         *
 *   This library 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     *
 *   Lesser General Public License for more details.                       *
 *                                                                         *
 *   You should have received a copy of the GNU Lesser General Public      *
 *   License along with this library; if not, write to the                 *
 *   Free Software Foundation, Inc.,                                       *
 *   51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA          *
 ***************************************************************************/

#ifndef FIFE_SINGLETON_H
#define FIFE_SINGLETON_H

#define SINGLEFRIEND(classname) friend class FIFE::StaticSingleton<classname>; classname(); virtual ~classname();

// Standard C++ library includes
#include <cassert>

// 3rd party library includes

// FIFE includes
// These includes are split up in two parts, separated by one empty line
// First block: files included from the FIFE root src directory
// Second block: files included from the same folder
#include "fifeclass.h"

namespace FIFE {

    template <typename T> class StaticSingleton {
        public:

            static T* instance() {
                static T inst;
                return &inst;
            }

        protected:

            StaticSingleton() {
            }

            virtual ~StaticSingleton() {
            }

        private:
            StaticSingleton(const StaticSingleton<T>&) {}
            StaticSingleton<T>& operator=(const StaticSingleton<T>&) {
                return this;
            }

    };

    template <typename T> class DynamicSingleton {
        public:
            static T* instance() {
                assert(m_instance);
                return m_instance;
            }

            DynamicSingleton() {
                assert(!m_instance);
                m_instance = static_cast<T*>(this);
            }

            virtual ~DynamicSingleton() {
                m_instance = 0;
            }

        private:
            static T* m_instance;

            DynamicSingleton(const DynamicSingleton<T>&) {};
            DynamicSingleton<T&> operator=(const DynamicSingleton<T>&) {};

    };

    template <typename T> T* DynamicSingleton<T>::m_instance = 0;

}//FIFE

#endif