/*

 * Copyright 1999 Sun Microsystems, Inc.  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.  Sun designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 */

package java.awt.font;

import java.text.CharacterIterator;

class CharArrayIterator implements CharacterIterator {

    private char[] chars;

    private int pos;

    private int begin;

    CharArrayIterator(char[] chars) {

        reset(chars, 0);

    }

    CharArrayIterator(char[] chars, int begin) {

        reset(chars, begin);

    }

    /**

     * Sets the position to getBeginIndex() and returns the character at that

     * position.

     * @return the first character in the text, or DONE if the text is empty

     * @see getBeginIndex

     */

    public char first() {

        pos = 0;

        return current();

    }

    /**

     * Sets the position to getEndIndex()-1 (getEndIndex() if the text is empty)

     * and returns the character at that position.

     * @return the last character in the text, or DONE if the text is empty

     * @see getEndIndex

     */

    public char last() {

        if (chars.length > 0) {

            pos = chars.length-1;

        }

        else {

            pos = 0;

        }

        return current();

    }

    /**

     * Gets the character at the current position (as returned by getIndex()).

     * @return the character at the current position or DONE if the current

     * position is off the end of the text.

     * @see getIndex

     */

    public char current() {

        if (pos >= 0 && pos < chars.length) {

            return chars[pos];

        }

        else {

            return DONE;

        }

    }

    /**

     * Increments the iterator's index by one and returns the character

     * at the new index.  If the resulting index is greater or equal

     * to getEndIndex(), the current index is reset to getEndIndex() and

     * a value of DONE is returned.

     * @return the character at the new position or DONE if the new

     * position is off the end of the text range.

     */

    public char next() {

        if (pos < chars.length-1) {

            pos++;

            return chars[pos];

        }

        else {

            pos = chars.length;

            return DONE;

        }

    }

    /**

     * Decrements the iterator's index by one and returns the character

     * at the new index. If the current index is getBeginIndex(), the index

     * remains at getBeginIndex() and a value of DONE is returned.

     * @return the character at the new position or DONE if the current

     * position is equal to getBeginIndex().

     */

    public char previous() {

        if (pos > 0) {

            pos--;

            return chars[pos];

        }

        else {

            pos = 0;

            return DONE;

        }

    }

    /**

     * Sets the position to the specified position in the text and returns that

     * character.

     * @param position the position within the text.  Valid values range from

     * getBeginIndex() to getEndIndex().  An IllegalArgumentException is thrown

     * if an invalid value is supplied.

     * @return the character at the specified position or DONE if the specified position is equal to getEndIndex()

     */

    public char setIndex(int position) {

        position -= begin;

        if (position < 0 || position > chars.length) {

            throw new IllegalArgumentException("Invalid index");

        }

        pos = position;

        return current();

    }

    /**

     * Returns the start index of the text.

     * @return the index at which the text begins.

     */

    public int getBeginIndex() {

        return begin;

    }

    /**

     * Returns the end index of the text.  This index is the index of the first

     * character following the end of the text.

     * @return the index after the last character in the text

     */

    public int getEndIndex() {

        return begin+chars.length;

    }

    /**

     * Returns the current index.

     * @return the current index.

     */

    public int getIndex() {

        return begin+pos;

    }

    /**

     * Create a copy of this iterator

     * @return A copy of this

     */

    public Object clone() {

        CharArrayIterator c = new CharArrayIterator(chars, begin);

        c.pos = this.pos;

        return c;

    }

    void reset(char[] chars) {

        reset(chars, 0);

    }

    void reset(char[] chars, int begin) {

        this.chars = chars;

        this.begin = begin;

        pos = 0;

    }

}