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/*
 * This file is part of choco-solver, http://choco-solver.org/
 *
 * Copyright (c) 2024, IMT Atlantique. All rights reserved.
 *
 * Licensed under the BSD 4-clause license.
 *
 * See LICENSE file in the project root for full license information.
 */
package org.chocosolver.solver.variables.delta;

import org.chocosolver.memory.IEnvironment;
import org.chocosolver.solver.ICause;
import org.chocosolver.solver.search.loop.TimeStampedObject;
import org.chocosolver.util.tools.ArrayUtils;

import java.util.Arrays;

/**
 * A class to store the removed value of an integer variable.
 * 
 * It defines methods to add a value, clear the structure
 * and execute a Procedure for each value stored.
 */
public final class EnumDelta extends TimeStampedObject implements IEnumDelta {
    private static final int SIZE = 32;

    private int[] rem;
    private ICause[] causes;
    private int last;

    public EnumDelta(IEnvironment environment) {
        super(environment);
        rem = new int[SIZE];
        causes = new ICause[SIZE];
    }

    private void ensureCapacity() {
        if (last >= rem.length) {
            int nsize = ArrayUtils.newBoundedSize(last, rem.length * 2);
            rem = Arrays.copyOf(rem, nsize);
            causes = Arrays.copyOf(causes, nsize);
        }
    }

    @Override
    public void lazyClear() {
        if (needReset()) {
            last = 0;
            resetStamp();
        }
    }

    /**
     * Adds a new value to the delta
     *
     * @param value value to add
     * @param cause of the removal
     */
    @Override
    public void add(int value, ICause cause) {
        lazyClear();
        ensureCapacity();
        causes[last] = cause;
        rem[last++] = value;
    }

    @Override
    public int get(int idx) {
        return rem[idx];
    }

    @Override
    public ICause getCause(int idx) {
        return causes[idx];
    }

    @Override
    public int size() {
        return last;
    }
}