[25584] | 1 | /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
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| 2 | * JFlex 1.4.3 *
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| 3 | * Copyright (C) 1998-2009 Gerwin Klein <[email protected]> *
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| 4 | * All rights reserved. *
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| 5 | * *
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| 6 | * This program is free software; you can redistribute it and/or modify *
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| 7 | * it under the terms of the GNU General Public License. See the file *
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| 8 | * COPYRIGHT for more information. *
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| 9 | * *
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| 10 | * This program is distributed in the hope that it will be useful, *
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| 11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of *
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| 12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
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| 13 | * GNU General Public License for more details. *
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| 14 | * *
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| 15 | * You should have received a copy of the GNU General Public License along *
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| 16 | * with this program; if not, write to the Free Software Foundation, Inc., *
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| 17 | * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA *
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| 18 | * *
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| 19 | * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
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| 20 | package JFlex;
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| 21 |
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| 22 | /**
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| 23 | * Enumerates the states of a StateSet.
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| 24 | *
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| 25 | * @author Gerwin Klein
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| 26 | * @version JFlex 1.4.3, $Revision: 433 $, $Date: 2009-01-31 19:52:34 +1100 (Sat, 31 Jan 2009) $
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| 27 | */
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| 28 | final public class StateSetEnumerator {
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| 29 |
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| 30 | private final static boolean DEBUG = false;
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| 31 |
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| 32 | private int index;
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| 33 | private int offset;
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| 34 | private long mask;
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| 35 |
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| 36 | private long [] bits;
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| 37 |
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| 38 | /**
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| 39 | * creates a new StateSetEnumerator that is not yet associated
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| 40 | * with a StateSet. hasMoreElements() and nextElement() will
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| 41 | * throw NullPointerException when used before reset()
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| 42 | */
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| 43 | public StateSetEnumerator() {
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| 44 | }
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| 45 |
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| 46 | public StateSetEnumerator(StateSet states) {
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| 47 | reset(states);
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| 48 | }
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| 49 |
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| 50 | public void reset(StateSet states) {
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| 51 | bits = states.bits;
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| 52 | index = 0;
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| 53 | offset = 0;
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| 54 | mask = 1;
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| 55 | while (index < bits.length && bits[index] == 0)
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| 56 | index++;
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| 57 |
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| 58 | if (index >= bits.length) return;
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| 59 |
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| 60 | while (offset <= StateSet.MASK && ((bits[index] & mask) == 0)) {
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| 61 | mask<<= 1;
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| 62 | offset++;
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| 63 | }
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| 64 | }
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| 65 |
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| 66 | private void advance() {
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| 67 |
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| 68 | if (DEBUG) Out.dump("Advancing, at start, index = "+index+", offset = "+offset); //$NON-NLS-1$ //$NON-NLS-2$
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| 69 |
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| 70 | // cache fields in local variable for faster access
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| 71 | int _index = this.index;
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| 72 | int _offset = this.offset;
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| 73 | long _mask = this.mask;
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| 74 | long [] _bits = this.bits;
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| 75 |
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| 76 | long bi = _bits[_index];
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| 77 |
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| 78 | do {
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| 79 | _offset++;
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| 80 | _mask<<= 1;
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| 81 | } while (_offset <= StateSet.MASK && ((bi & _mask) == 0));
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| 82 |
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| 83 | if (_offset > StateSet.MASK) {
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| 84 | int length = _bits.length;
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| 85 |
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| 86 | do
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| 87 | _index++;
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| 88 | while (_index < length && _bits[_index] == 0);
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| 89 |
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| 90 | if (_index >= length) {
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| 91 | this.index = length; // indicates "no more elements"
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| 92 | return;
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| 93 | }
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| 94 |
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| 95 | _offset = 0;
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| 96 | _mask = 1;
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| 97 | bi = _bits[_index];
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| 98 |
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| 99 | // terminates, because bi != 0
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| 100 | while ((bi & _mask) == 0) {
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| 101 | _mask<<= 1;
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| 102 | _offset++;
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| 103 | }
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| 104 | }
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| 105 |
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| 106 | // write back cached values
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| 107 | this.index = _index;
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| 108 | this.mask = _mask;
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| 109 | this.offset = _offset;
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| 110 | }
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| 111 |
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| 112 | public boolean hasMoreElements() {
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| 113 | if (DEBUG) Out.dump("hasMoreElements, index = "+index+", offset = "+offset); //$NON-NLS-1$ //$NON-NLS-2$
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| 114 | return index < bits.length;
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| 115 | }
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| 116 |
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| 117 | public int nextElement() {
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| 118 | if (DEBUG) Out.dump("nextElement, index = "+index+", offset = "+offset); //$NON-NLS-1$ //$NON-NLS-2$
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| 119 | int x = (index << StateSet.BITS) + offset;
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| 120 | advance();
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| 121 | return x;
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| 122 | }
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| 123 |
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| 124 | }
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