/*
 * Copyright (c) 2001, 2005, 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
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 */

package sun.text;

import sun.text.normalizer.NormalizerBase;
import sun.text.normalizer.NormalizerImpl;

public final class ComposedCharIter {
    /**
     * Constant that indicates the iteration has completed.
     * {@link #next} returns this value when there are no more composed characters
     * over which to iterate.
     */
    public static final int DONE = NormalizerBase.DONE;

    //cache the decomps mapping, so the seconde composedcharIter does
    //not need to get the data again.
    private static int chars[];
    private static String decomps[];
    private static int decompNum;

    static {
        int maxNum = 2000;     //TBD: Unicode 4.0 only has 1926 canoDecomp...
        chars = new int[maxNum];
        decomps = new String[maxNum];
        decompNum = NormalizerImpl.getDecompose(chars, decomps);
    }

    /**
     * Construct a new <tt>ComposedCharIter</tt>.  The iterator will return
     * all Unicode characters with canonical decompositions, excluding Korean
     * Hangul characters.
     */
    public ComposedCharIter() { }

    /**
     * Returns the next precomposed Unicode character.
     * Repeated calls to <tt>next</tt> return all of the precomposed characters defined
     * by Unicode, in ascending order.  After all precomposed characters have
     * been returned, hasNext will return <tt>false</tt> and further calls
     * to <tt>next</tt> will return {@link #DONE}.
     */
    public int next() {
        if (curChar == decompNum - 1) {
            return DONE;
        }
        return chars[++curChar];
    }

    /**
     * Returns the Unicode decomposition of the current character.
     * This method returns the decomposition of the precomposed character most
     * recently returned by {@link #next}.  The resulting decomposition is
     * affected by the settings of the options passed to the constructor.
     */
    public String decomposition() {
        return decomps[curChar];
    }
    private int curChar = -1;
}
