/**
* Copyright (c) 1999-2014, Ecole des Mines de Nantes
* All rights reserved.
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* * Neither the name of the Ecole des Mines de Nantes nor the
* names of its contributors may be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE REGENTS AND CONTRIBUTORS BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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*/
package solver.constraints.extension.binary;
import gnu.trove.map.hash.THashMap;
import solver.Solver;
import solver.constraints.extension.Tuples;
import solver.exception.ContradictionException;
import solver.variables.IntVar;
import solver.variables.events.IntEventType;
import util.iterators.DisposableValueIterator;
/**
* Forward checking algorithm for table constraint
* <br/>
*
* @author Charles Prud'homme, Hadrien Cambazard
* @since 24/04/2014
*/
public class PropBinFC extends PropBinCSP {
public PropBinFC(IntVar x, IntVar y, Tuples tuples) {
this(x, y, new CouplesTable(tuples, x, y));
}
private PropBinFC(IntVar x, IntVar y, CouplesTable table) {
super(x, y, table);
}
@Override
protected int getPropagationConditions(int vIdx) {
return IntEventType.instantiation();
}
@Override
public void propagate(int evtmask) throws ContradictionException {
if (v0.isInstantiated())
onInstantiation0();
if (v1.isInstantiated())
onInstantiation1();
}
@Override
public void propagate(int idxVarInProp, int mask) throws ContradictionException {
if (idxVarInProp == 0) onInstantiation0();
else onInstantiation1();
}
@Override
public void duplicate(Solver solver, THashMap<Object, Object> identitymap) {
if (!identitymap.containsKey(this)) {
this.vars[0].duplicate(solver, identitymap);
IntVar X = (IntVar) identitymap.get(this.vars[0]);
this.vars[1].duplicate(solver, identitymap);
IntVar Y = (IntVar) identitymap.get(this.vars[1]);
identitymap.put(this, new PropBinFC(X, Y, (CouplesTable) relation.duplicate()));
}
}
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
private void onInstantiation0() throws ContradictionException {
int left, right;
int value = v0.getValue();
DisposableValueIterator values = v1.getValueIterator(true);
left = right = Integer.MIN_VALUE;
try {
while (values.hasNext()) {
int val = values.next();
if (!relation.isConsistent(value, val)) {
if (val == right + 1) {
right = val;
} else {
v1.removeInterval(left, right, this);
left = right = val;
}
}
}
v1.removeInterval(left, right, this);
} finally {
values.dispose();
}
}
private void onInstantiation1() throws ContradictionException {
int left, right;
int value = v1.getValue();
DisposableValueIterator values = v0.getValueIterator(true);
left = right = Integer.MIN_VALUE;
try {
while (values.hasNext()) {
int val = values.next();
if (!relation.isConsistent(val, value)) {
if (val == right + 1) {
right = val;
} else {
v0.removeInterval(left, right, this);
left = right = val;
}
}
}
v0.removeInterval(left, right, this);
} finally {
values.dispose();
}
}
}