| /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * |
| * JFlex 1.4.3 * |
| * Copyright (C) 1998-2009 Gerwin Klein <lsf@jflex.de> * |
| * All rights reserved. * |
| * * |
| * This program is free software; you can redistribute it and/or modify * |
| * it under the terms of the GNU General Public License. See the file * |
| * COPYRIGHT for more information. * |
| * * |
| * This program 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 this program; if not, write to the Free Software Foundation, Inc., * |
| * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA * |
| * * |
| * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */ |
| package JFlex; |
| |
| /** |
| * Enumerates the states of a StateSet. |
| * |
| * @author Gerwin Klein |
| * @version $Revision: 1.4.3 $, $Date: 2009/12/21 15:58:48 $ |
| */ |
| final public class StateSetEnumerator { |
| |
| private final static boolean DEBUG = false; |
| |
| private int index; |
| private int offset; |
| private long mask; |
| |
| private long [] bits; |
| |
| /** |
| * creates a new StateSetEnumerator that is not yet associated |
| * with a StateSet. hasMoreElements() and nextElement() will |
| * throw NullPointerException when used before reset() |
| */ |
| public StateSetEnumerator() { |
| } |
| |
| public StateSetEnumerator(StateSet states) { |
| reset(states); |
| } |
| |
| public void reset(StateSet states) { |
| bits = states.bits; |
| index = 0; |
| offset = 0; |
| mask = 1; |
| while (index < bits.length && bits[index] == 0) |
| index++; |
| |
| if (index >= bits.length) return; |
| |
| while (offset <= StateSet.MASK && ((bits[index] & mask) == 0)) { |
| mask<<= 1; |
| offset++; |
| } |
| } |
| |
| private void advance() { |
| |
| if (DEBUG) Out.dump("Advancing, at start, index = "+index+", offset = "+offset); //$NON-NLS-1$ //$NON-NLS-2$ |
| |
| // cache fields in local variable for faster access |
| int _index = this.index; |
| int _offset = this.offset; |
| long _mask = this.mask; |
| long [] _bits = this.bits; |
| |
| long bi = _bits[_index]; |
| |
| do { |
| _offset++; |
| _mask<<= 1; |
| } while (_offset <= StateSet.MASK && ((bi & _mask) == 0)); |
| |
| if (_offset > StateSet.MASK) { |
| int length = _bits.length; |
| |
| do |
| _index++; |
| while (_index < length && _bits[_index] == 0); |
| |
| if (_index >= length) { |
| this.index = length; // indicates "no more elements" |
| return; |
| } |
| |
| _offset = 0; |
| _mask = 1; |
| bi = _bits[_index]; |
| |
| // terminates, because bi != 0 |
| while ((bi & _mask) == 0) { |
| _mask<<= 1; |
| _offset++; |
| } |
| } |
| |
| // write back cached values |
| this.index = _index; |
| this.mask = _mask; |
| this.offset = _offset; |
| } |
| |
| public boolean hasMoreElements() { |
| if (DEBUG) Out.dump("hasMoreElements, index = "+index+", offset = "+offset); //$NON-NLS-1$ //$NON-NLS-2$ |
| return index < bits.length; |
| } |
| |
| public int nextElement() { |
| if (DEBUG) Out.dump("nextElement, index = "+index+", offset = "+offset); //$NON-NLS-1$ //$NON-NLS-2$ |
| int x = (index << StateSet.BITS) + offset; |
| advance(); |
| return x; |
| } |
| |
| } |