1 /*******************************************************************************
2 * SAT4J: a SATisfiability library for Java Copyright (C) 2004-2008 Daniel Le Berre
3 *
4 * All rights reserved. This program and the accompanying materials
5 * are made available under the terms of the Eclipse Public License v1.0
6 * which accompanies this distribution, and is available at
7 * http://www.eclipse.org/legal/epl-v10.html
8 *
9 * Alternatively, the contents of this file may be used under the terms of
10 * either the GNU Lesser General Public License Version 2.1 or later (the
11 * "LGPL"), in which case the provisions of the LGPL are applicable instead
12 * of those above. If you wish to allow use of your version of this file only
13 * under the terms of the LGPL, and not to allow others to use your version of
14 * this file under the terms of the EPL, indicate your decision by deleting
15 * the provisions above and replace them with the notice and other provisions
16 * required by the LGPL. If you do not delete the provisions above, a recipient
17 * may use your version of this file under the terms of the EPL or the LGPL.
18 *
19 * Based on the original MiniSat specification from:
20 *
21 * An extensible SAT solver. Niklas Een and Niklas Sorensson. Proceedings of the
22 * Sixth International Conference on Theory and Applications of Satisfiability
23 * Testing, LNCS 2919, pp 502-518, 2003.
24 *
25 * See www.minisat.se for the original solver in C++.
26 *
27 *******************************************************************************/
28 package org.sat4j.minisat.constraints;
29
30 import org.sat4j.minisat.constraints.cnf.Clauses;
31 import org.sat4j.minisat.constraints.cnf.LearntHTClause;
32 import org.sat4j.minisat.constraints.cnf.Lits;
33 import org.sat4j.minisat.constraints.cnf.OriginalHTClause;
34 import org.sat4j.minisat.constraints.cnf.UnitClause;
35 import org.sat4j.minisat.core.Constr;
36 import org.sat4j.minisat.core.ILits;
37 import org.sat4j.specs.ContradictionException;
38 import org.sat4j.specs.IVecInt;
39
40 /**
41 * Uses Head Tail data structure for both original clauses and learned clauses.
42 *
43 * @author leberre
44 */
45 public class ClausalDataStructureHT extends AbstractDataStructureFactory<ILits> {
46
47 private static final long serialVersionUID = 1L;
48
49 /*
50 * (non-Javadoc)
51 *
52 * @see org.sat4j.minisat.DataStructureFactory#createClause(org.sat4j.datatype.VecInt)
53 */
54 public Constr createClause(IVecInt literals) throws ContradictionException {
55 IVecInt v = Clauses.sanityCheck(literals, getVocabulary(), solver);
56 if (v == null)
57 return null;
58 return OriginalHTClause.brandNewClause(solver, getVocabulary(), v);
59 }
60
61 public Constr createUnregisteredClause(IVecInt literals) {
62 if (literals.size()==1) {
63 return new UnitClause(literals.last());
64 }
65 return new LearntHTClause(literals, getVocabulary());
66 }
67
68 @Override
69 protected ILits createLits() {
70 return new Lits();
71 }
72 }