| /* gnu/regexp/CharIndexed.java |
| Copyright (C) 1998-2001, 2004 Free Software Foundation, Inc. |
| |
| This file is part of GNU Classpath. |
| |
| GNU Classpath is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 2, or (at your option) |
| any later version. |
| |
| GNU Classpath 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 for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with GNU Classpath; see the file COPYING. If not, write to the |
| Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA |
| 02111-1307 USA. |
| |
| Linking this library statically or dynamically with other modules is |
| making a combined work based on this library. Thus, the terms and |
| conditions of the GNU General Public License cover the whole |
| combination. |
| |
| As a special exception, the copyright holders of this library give you |
| permission to link this library with independent modules to produce an |
| executable, regardless of the license terms of these independent |
| modules, and to copy and distribute the resulting executable under |
| terms of your choice, provided that you also meet, for each linked |
| independent module, the terms and conditions of the license of that |
| module. An independent module is a module which is not derived from |
| or based on this library. If you modify this library, you may extend |
| this exception to your version of the library, but you are not |
| obligated to do so. If you do not wish to do so, delete this |
| exception statement from your version. */ |
| |
| package gnu.regexp; |
| |
| /** |
| * Defines the interface used internally so that different types of source |
| * text can be accessed in the same way. Built-in concrete classes provide |
| * support for String, StringBuffer, InputStream and char[] types. |
| * A class that is CharIndexed supports the notion of a cursor within a |
| * block of text. The cursor must be able to be advanced via the move() |
| * method. The charAt() method returns the character at the cursor position |
| * plus a given offset. |
| * |
| * @author <A HREF="mailto:wes@cacas.org">Wes Biggs</A> |
| */ |
| public interface CharIndexed { |
| /** |
| * Defines a constant (0xFFFF was somewhat arbitrarily chosen) |
| * that can be returned by the charAt() function indicating that |
| * the specified index is out of range. |
| */ |
| char OUT_OF_BOUNDS = '\uFFFF'; |
| |
| /** |
| * Returns the character at the given offset past the current cursor |
| * position in the input. The index of the current position is zero. |
| * It is possible for this method to be called with a negative index. |
| * This happens when using the '^' operator in multiline matching mode |
| * or the '\b' or '\<' word boundary operators. In any case, the lower |
| * bound is currently fixed at -2 (for '^' with a two-character newline). |
| * |
| * @param index the offset position in the character field to examine |
| * @return the character at the specified index, or the OUT_OF_BOUNDS |
| * character defined by this interface. |
| */ |
| char charAt(int index); |
| |
| /** |
| * Shifts the input buffer by a given number of positions. Returns |
| * true if the new cursor position is valid. |
| */ |
| boolean move(int index); |
| |
| /** |
| * Returns true if the most recent move() operation placed the cursor |
| * position at a valid position in the input. |
| */ |
| boolean isValid(); |
| } |