src/main/java/freemarker/core/NumericalRange.java

/*
 * Copyright (c) 2003 The Visigoth Software Society. 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. The end-user documentation included with the redistribution, if
 *    any, must include the following acknowledgement:
 *       "This product includes software developed by the
 *        Visigoth Software Society (http://www.visigoths.org/)."
 *    Alternately, this acknowledgement may appear in the software itself,
 *    if and wherever such third-party acknowledgements normally appear.
 *
 * 4. Neither the name "FreeMarker", "Visigoth", nor any of the names of the 
 *    project contributors may be used to endorse or promote products derived
 *    from this software without prior written permission. For written
 *    permission, please contact visigoths@visigoths.org.
 *
 * 5. Products derived from this software may not be called "FreeMarker" or "Visigoth"
 *    nor may "FreeMarker" or "Visigoth" appear in their names
 *    without prior written permission of the Visigoth Software Society.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED 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 THE VISIGOTH SOFTWARE SOCIETY OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Visigoth Software Society. For more
 * information on the Visigoth Software Society, please see
 * http://www.visigoths.org/
 */

package freemarker.core;

import freemarker.template.SimpleNumber;
import freemarker.template.TemplateModel;
import freemarker.template.TemplateModelException;
import freemarker.template.TemplateSequenceModel;

/**
 * A class that represents a Range between two integers.
 * inclusive of the end-points. It can be ascending or
 * descending. 
 * @author <a href="mailto:jon@revusky.com">Jonathan Revusky</a>
 */
class NumericalRange implements TemplateSequenceModel, java.io.Serializable {

    private int lower, upper;
    private boolean descending, norhs; // if norhs is true, then we have a half-range, like n..
    
    
    /**
     * Constructor for half-range, i.e. n..
     */
    public NumericalRange(int lower) {
        this.norhs = true;
        this.lower = lower;
    }

    public NumericalRange(int left, int right) {
        lower = Math.min(left, right);
        upper = Math.max(left, right);
        descending = (left != lower);
    }

    public TemplateModel get(int i) throws TemplateModelException {
        int index = descending ? (upper -i) : (lower + i);
        if ((norhs && index > upper) || index <lower) {
            throw new _TemplateModelException(new Object[] {
                    "Range item index ", new Integer(i), " is out of bounds." });
        }
        return new SimpleNumber(index);
    }

    public int size() {
        return 1 + upper - lower;
    }
    
    boolean hasRhs() {
        return !norhs;
    }
}