substring.java

javascript语言的解释器源码

/* -*- Mode: java; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
 *
 * The contents of this file are subject to the Netscape Public
 * License Version 1.1 (the "License"); you may not use this file
 * except in compliance with the License. You may obtain a copy of
 * the License at http://www.mozilla.org/NPL/
 *
 * Software distributed under the License is distributed on an "AS
 * IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
 * implied. See the License for the specific language governing
 * rights and limitations under the License.
 *
 * The Original Code is Rhino code, released
 * May 6, 1998.
 *
 * The Initial Developer of the Original Code is Netscape
 * Communications Corporation.  Portions created by Netscape are
 * Copyright (C) 1997-1999 Netscape Communications Corporation. All
 * Rights Reserved.
 *
 * Contributor(s):
 *
 * Alternatively, the contents of this file may be used under the
 * terms of the GNU Public License (the "GPL"), in which case the
 * provisions of the GPL are applicable instead of those above.
 * If you wish to allow use of your version of this file only
 * under the terms of the GPL and not to allow others to use your
 * version of this file under the NPL, indicate your decision by
 * deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL.  If you do not delete
 * the provisions above, a recipient may use your version of this
 * file under either the NPL or the GPL.
 */

package org.mozilla.javascript.regexp;

class SubString {

    public SubString()
    {
    }

    public SubString(String str)
    {
        index = 0;
        charArray = str.toCharArray();
        length = str.length();
    }

    public SubString(char[] source, int start, int len)
    {
    // there must be a better way of doing this??
        index = 0;
        length = len;
        charArray = new char[len];
        for (int j = 0; j < len; j++)
            charArray[j] = source[start + j];
    }

    public String toString() {
        return charArray == null
               ? ""
               : new String(charArray, index, length);
    }

    static final SubString emptySubString = new SubString();

    char[] charArray;
    int    index;
    int    length;
}