| /***** BEGIN LICENSE BLOCK ***** |
| * Version: CPL 1.0/GPL 2.0/LGPL 2.1 |
| * |
| * The contents of this file are subject to the Common Public |
| * License Version 1.0 (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.eclipse.org/legal/cpl-v10.html |
| * |
| * 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. |
| * |
| * Copyright (C) 2002 Jan Arne Petersen <jpetersen@uni-bonn.de> |
| * Copyright (C) 2004 Stefan Matthias Aust <sma@3plus4.de> |
| * |
| * Alternatively, the contents of this file may be used under the terms of |
| * either of the GNU General Public License Version 2 or later (the "GPL"), |
| * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"), |
| * in which case the provisions of the GPL or the LGPL are applicable instead |
| * of those above. If you wish to allow use of your version of this file only |
| * under the terms of either the GPL or the LGPL, and not to allow others to |
| * use your version of this file under the terms of the CPL, indicate your |
| * decision by deleting the provisions above and replace them with the notice |
| * and other provisions required by the GPL or the LGPL. If you do not delete |
| * the provisions above, a recipient may use your version of this file under |
| * the terms of any one of the CPL, the GPL or the LGPL. |
| ***** END LICENSE BLOCK *****/ |
| package org.jruby.lexer.yacc; |
| |
| /** |
| * |
| * @author jpetersen |
| */ |
| public class StackState implements Cloneable { |
| private long stack = 0; |
| |
| public void reset() { |
| reset(0); |
| } |
| |
| public void reset(long backup) { |
| stack = backup; |
| } |
| |
| public long begin() { |
| long old = stack; |
| stack <<= 1; |
| stack |= 1; |
| return old; |
| } |
| |
| public void end() { |
| stack >>= 1; |
| } |
| |
| public void stop() { |
| stack <<= 1; |
| } |
| |
| public void restart() { |
| stack |= (stack & 1) << 1; |
| stack >>= 1; |
| } |
| |
| public boolean isInState() { |
| return (stack & 1) != 0; |
| } |
| } |