singleton.hpp

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#ifndef GSGL_DATA_SINGLETON_H
#define GSGL_DATA_SINGLETON_H

//
// $Id: singleton.hpp 2 2008-03-01 20:58:50Z kulibali $
//
// Copyright (c) 2008, The Periapsis Project. All rights reserved. 
// 
// Redistribution and use in source and binary forms, with or without 
// modification, are permitted provided that the following conditions are 
// met: 
// 
// * Redistributions of source code must retain the above copyright notice, 
//   this list of conditions and the following disclaimer. 
// 
// * Redistributions in binary form must reproduce the above copyright 
//   notice, this list of conditions and the following disclaimer in the 
//   documentation and/or other materials provided with the distribution. 
// 
// * Neither the name of the The Periapsis Project nor the names of its 
//   contributors may be used to endorse or promote products derived from 
//   this software without specific prior written permission. 
// 
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS 
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//

#include "data/data.hpp"
#include "data/exception.hpp"

#ifdef WIN32
#pragma warning (disable: 4661)
#endif

namespace gsgl
{

    namespace data
    {


        template <typename T>
        class singleton
            : public gsgl::data_object
        {
            static T *instance;
        public:
            singleton()
                : data_object()
            {
                if (instance)
                    throw gsgl::internal_exception(__FILE__, __LINE__, L"Attempted to create more than one of a singleton class.");
                instance = reinterpret_cast<T *>(this);
            }

            virtual ~singleton()
            {
                instance = 0;
            }

            static T *global_instance()
            {
                return T::instance;
            }
        }; // class singleton


    } // namespace data

} // namespace gsgl

#endif

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