/*

 * Copyright (c) 2009, 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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 */

/*

 *******************************************************************************

 * (C) Copyright IBM Corp. and others, 1996-2009 - All Rights Reserved         *

 *                                                                             *

 * The original version of this source code and documentation is copyrighted   *

 * and owned by IBM, These materials are provided under terms of a License     *

 * Agreement between IBM and Sun. This technology is protected by multiple     *

 * US and International patents. This notice and attribution to IBM may not    *

 * to removed.                                                                 *

 *******************************************************************************

 */

/* Written by Simon Montagu, Matitiahu Allouche

 * (ported from C code written by Markus W. Scherer)

 */

package sun.text.bidi;

/**

 * A BidiRun represents a sequence of characters at the same embedding level.

 * The Bidi algorithm decomposes a piece of text into sequences of characters

 * at the same embedding level, each such sequence is called a <quote>run</quote>.

 *

 * <p>A BidiRun represents such a run by storing its essential properties,

 * but does not duplicate the characters which form the run.

 *

 * <p>The &quot;limit&quot; of the run is the position just after the

 * last character, i.e., one more than that position.

 *

 * <p>This class has no public constructor, and its members cannot be

 * modified by users.

 *

 * @see com.ibm.icu.text.Bidi

 */

public class BidiRun {

    int start;              /* first logical position of the run */

    int limit;              /* last visual position of the run +1 */

    int insertRemove;       /* if >0, flags for inserting LRM/RLM before/after run,

                               if <0, count of bidi controls within run            */

    byte level;

    /*

     * Default constructor

     *

     * Note that members start and limit of a run instance have different

     * meanings depending whether the run is part of the runs array of a Bidi

     * object, or if it is a reference returned by getVisualRun() or

     * getLogicalRun().

     * For a member of the runs array of a Bidi object,

     *   - start is the first logical position of the run in the source text.

     *   - limit is one after the last visual position of the run.

     * For a reference returned by getLogicalRun() or getVisualRun(),

     *   - start is the first logical position of the run in the source text.

     *   - limit is one after the last logical position of the run.

     */

    BidiRun()

    {

        this(0, 0, (byte)0);

    }

    /*

     * Constructor

     */

    BidiRun(int start, int limit, byte embeddingLevel)

    {

        this.start = start;

        this.limit = limit;

        this.level = embeddingLevel;

    }

    /*

     * Copy the content of a BidiRun instance

     */

    void copyFrom(BidiRun run)

    {

        this.start = run.start;

        this.limit = run.limit;

        this.level = run.level;

        this.insertRemove = run.insertRemove;

    }

    /**

     * Get level of run

     */

    public byte getEmbeddingLevel()

    {

        return level;

    }

    /**

     * Check if run level is even

     * @return true if the embedding level of this run is even, i.e. it is a

     *  left-to-right run.

     */

    boolean isEvenRun()

    {

        return (level & 1) == 0;

    }

}