/*******************************************************************************
 * Copyright (c) 2000, 2008 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.compare.rangedifferencer;

import java.util.ArrayList;
import java.util.List;

/**
 * A custom iterator to iterate over a List of <code>RangeDifferences</code>.
 * It is used internally by the <code>RangeDifferencer</code>.
 */
/* package */ class DifferencesIterator {

    List fRange;
    int fIndex;
    RangeDifference[] fArray;   
    RangeDifference fDifference;
    
    /*
     * Creates a differences iterator on an array of <code>RangeDifference</code>s.
     */
    DifferencesIterator(RangeDifference[] differenceRanges) {
        
        fArray= differenceRanges;
        fIndex= 0;
        fRange= new ArrayList();
        if (fIndex < fArray.length)
            fDifference= fArray[fIndex++];
        else
            fDifference= null;
    }

    /*
      * Returns the number of RangeDifferences
      */
    int getCount() {
        return fRange.size();
    }

    /*
     * Appends the edit to its list and moves to the next <code>RangeDifference</code>.
     */
    void next() {
        fRange.add(fDifference);
        if (fDifference != null) {
            if (fIndex < fArray.length)
                fDifference= fArray[fIndex++];
            else
                fDifference= null;
        }
    }

    /*
     * Difference iterators are used in pairs.
     * This method returns the other iterator.
     */
    DifferencesIterator other(DifferencesIterator right, DifferencesIterator left) {
        if (this == right)
            return left;
        return right;
    }

    /*
      * Removes all <code>RangeDifference</code>s
      */
    void removeAll() {
        fRange.clear();
    }
}