HoldData.h

/* ScummVM - Graphic Adventure Engine
 *
 * ScummVM is the legal property of its developers, whose names
 * are too numerous to list here. Please refer to the COPYRIGHT
 * file distributed with this source distribution.
 *
 * 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 3 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, see <http://www.gnu.org/licenses/>.
 *
 */

#ifndef QDENGINE_MINIGAMES_ADV_HOLD_DATA_H
#define QDENGINE_MINIGAMES_ADV_HOLD_DATA_H

namespace QDEngine {

template <class T>
class HoldData {
    T _emptyData;
    T &_data;
    bool _empty;
public:
    HoldData() : _data(_emptyData), _empty(true) {}
    HoldData(T* data, bool empty)
        : _data(data ? * data : _emptyData) {
        _empty = data ? empty : true;
    }

    void process(T& current) {
        if (_empty) {
            _data = current;
            _empty = false;
        } else
            current = _data;
    }

    const T &get() const {
        assert(!_empty);
        return _data;
    }
};

} // namespace QDEngine

#endif // QDENGINE_MINIGAMES_ADV_HOLD_DATA_H