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Open-source constraint solver.
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/**
 * Copyright (c) 2016, Ecole des Mines de Nantes
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. 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.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *    This product includes software developed by the .
 * 4. Neither the name of the  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  ''AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL  BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
package org.chocosolver.memory.trailing;

import org.chocosolver.memory.IStateLong;
import org.chocosolver.memory.trailing.trail.IStoredLongTrail;


/**
 * A class implementing backtrackable long.
 */
public class StoredLong extends IStateLong {

    protected final IStoredLongTrail myTrail;

    /**
     * Constructs a stored search with an initial value.
     * Note: this constructor should not be used directly: one should instead
     * use the IEnvironment factory
     */
    public StoredLong(final EnvironmentTrailing env, final long i) {
        super(env, i);
        myTrail = env.getLongTrail();
        if(env.fakeHistoryNeeded()){
            myTrail.buildFakeHistory(this, i, timeStamp);
        }
    }

    /**
     * Modifies the value and stores if needed the former value on the
     * trailing stack.
     */
    @Override
    public final void set(final long y) {
        if (y != currentValue) {
            final int wi = environment.getWorldIndex();
            if (this.timeStamp < wi) {
                myTrail.savePreviousState(this, currentValue, timeStamp);
                timeStamp = wi;
            }
            currentValue = y;
        }
    }
}