shared_ptr.h

/*
 * shared_ptr.h
 * This file is part of dbPager Classes Library (DCL)
 *
 * Copyright (c) 2008 Dennis Prochko <wolfsoft@mail.ru>
 *
 * DCL 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 version 3.
 *
 * DCL 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 DCL; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor,
 * Boston, MA  02110-1301  USA
 */

#ifndef _SHARED_PTR_H_
#define _SHARED_PTR_H_

namespace dbp {

namespace local {

template <class T>
class smart_ptr {
public:
        smart_ptr(): _data(new T), _refcount(0) { };
        smart_ptr(T *data): _data(data), _refcount(0) { };
        smart_ptr(const smart_ptr<T> &src):
          _data(new T(*(src._data))), _refcount(0) { };
        ~smart_ptr() {
                delete _data;
        };
        smart_ptr<T>& operator=(const smart_ptr<T> &src) {
                if (this == &src)
                        return *this;
                delete _data;
                _data = new T(*(src._data));
                return *this;
        };
        T* operator->() const {
                return _data;
        };
        T& operator*() const {
                return *_data;
        };
        void invoke() { _refcount++; };
        void release() {
                if (_refcount > 0)
                        _refcount--;
                if (_refcount == 0) {
                        delete this;
                };
        };
private:
        T *_data;
        int _refcount;
};

} // namespace


template <class T>
class shared_ptr {
public:
        shared_ptr(): _data(new local::smart_ptr<T>) {
                _data->invoke();
        };
        shared_ptr(T *data): _data(new local::smart_ptr<T>(data)) {
                _data->invoke();
        };
        shared_ptr(const shared_ptr<T> &src): _data(src._data) {
                _data->invoke();
        };
        ~shared_ptr() {
                _data->release();
        };
        shared_ptr<T>& operator=(const shared_ptr<T> &src) {
                if ((this == &src) || (_data == src._data))
                        return *this;
                _data->release();
                _data = src._data;
                _data->invoke();
                return *this;
        };
        T* operator->() const {
                return &(**_data);
        };
        T& operator*() const {
                return *_data;
        };
        bool operator<(const shared_ptr<T> &src) const {
                return _data < src._data;
        };
private:
        local::smart_ptr<T> *_data;
};

}

#endif /*_SHARED_PTR_H_*/