/*
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 * Copyright 2018, Danny Robson <danny@nerdcruft.net>
 */

#pragma once


namespace util::scoped {
    ///////////////////////////////////////////////////////////////////////////
    /// restores a referenced target variable to its original value at
    /// destruction time. the type must be copyable.
    template <typename ValueT>
    class restore {
    public:
        restore (ValueT &_target):
            m_target (_target),
            m_value  (_target)
        { ; }

        ~restore ()
        {
            m_target = m_value;
        }

    private:
        ValueT &m_target;
        ValueT const m_value;
    };


    //-------------------------------------------------------------------------
    template <typename ValueT>
    restore (ValueT&) -> restore<ValueT>;
}