xref: /openjdk10/nashorn/src/jdk.scripting.nashorn/share/classes/jdk/nashorn/internal/runtime/arrays/ReverseScriptArrayIterator.java

/*
 * Copyright (c) 2010, 2013, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code 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
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
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 */

package jdk.nashorn.internal.runtime.arrays;

import jdk.nashorn.internal.runtime.ScriptObject;

/**
 * Reverse iterator over a NativeArray
 */
final class ReverseScriptArrayIterator extends ScriptArrayIterator {

    /**
     * Constructor
     * @param array array to iterate over
     * @param includeUndefined should undefined elements be included in iteration
     */
    public ReverseScriptArrayIterator(final ScriptObject array, final boolean includeUndefined) {
        super(array, includeUndefined);
        this.index = array.getArray().length() - 1;
    }

    @Override
    public boolean isReverse() {
        return true;
    }

    @Override
    protected boolean indexInArray() {
        return index >= 0;
    }

    @Override
    protected long bumpIndex() {
        return index--;
    }
}