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/********************* */
/*! \file theory_bool.cpp
** \verbatim
** Original author: mdeters
** Major contributors: none
** Minor contributors (to current version): none
** This file is part of the CVC4 prototype.
** Copyright (c) 2009, 2010, 2011 The Analysis of Computer Systems Group (ACSys)
** Courant Institute of Mathematical Sciences
** New York University
** See the file COPYING in the top-level source directory for licensing
** information.\endverbatim
**
** \brief The theory of booleans.
**
** The theory of booleans.
**/
#include "theory/theory.h"
#include "theory/booleans/theory_bool.h"
#include "theory/booleans/circuit_propagator.h"
#include "theory/valuation.h"
#include "util/boolean_simplification.h"
#include <vector>
#include <stack>
#include "util/hash.h"
using namespace std;
namespace CVC4 {
namespace theory {
namespace booleans {
Node TheoryBool::getValue(TNode n) {
NodeManager* nodeManager = NodeManager::currentNM();
switch(n.getKind()) {
case kind::VARIABLE:
// case for Boolean vars is implemented in TheoryEngine (since it
// appeals to the PropEngine to get the value)
Unreachable();
case kind::EQUAL: // 2 args
// should be handled by IFF
Unreachable();
case kind::NOT: // 1 arg
return nodeManager->mkConst(! d_valuation.getValue(n[0]).getConst<bool>());
case kind::AND: { // 2+ args
for(TNode::iterator i = n.begin(),
iend = n.end();
i != iend;
++i) {
if(! d_valuation.getValue(*i).getConst<bool>()) {
return nodeManager->mkConst(false);
}
}
return nodeManager->mkConst(true);
}
case kind::IFF: // 2 args
return nodeManager->mkConst( d_valuation.getValue(n[0]).getConst<bool>() ==
d_valuation.getValue(n[1]).getConst<bool>() );
case kind::IMPLIES: // 2 args
return nodeManager->mkConst( (! d_valuation.getValue(n[0]).getConst<bool>()) ||
d_valuation.getValue(n[1]).getConst<bool>() );
case kind::OR: { // 2+ args
for(TNode::iterator i = n.begin(),
iend = n.end();
i != iend;
++i) {
if(d_valuation.getValue(*i).getConst<bool>()) {
return nodeManager->mkConst(true);
}
}
return nodeManager->mkConst(false);
}
case kind::XOR: // 2 args
return nodeManager->mkConst( d_valuation.getValue(n[0]).getConst<bool>() !=
d_valuation.getValue(n[1]).getConst<bool>() );
case kind::ITE: // 3 args
// all ITEs should be gone except (bool,bool,bool) ones
Assert( n[1].getType() == nodeManager->booleanType() &&
n[2].getType() == nodeManager->booleanType() );
return nodeManager->mkConst( d_valuation.getValue(n[0]).getConst<bool>() ?
d_valuation.getValue(n[1]).getConst<bool>() :
d_valuation.getValue(n[2]).getConst<bool>() );
default:
Unhandled(n.getKind());
}
}
Theory::SolveStatus TheoryBool::solve(TNode in, SubstitutionMap& outSubstitutions) {
if (in.getKind() == kind::CONST_BOOLEAN && !in.getConst<bool>()) {
// If we get a false literal, we're in conflict
return SOLVE_STATUS_CONFLICT;
}
// Add the substitution from the variable to it's value
if (in.getKind() == kind::NOT) {
if (in[0].getKind() == kind::VARIABLE) {
outSubstitutions.addSubstitution(in[0], NodeManager::currentNM()->mkConst<bool>(false));
} else {
return SOLVE_STATUS_UNSOLVED;
}
} else {
if (in.getKind() == kind::VARIABLE) {
outSubstitutions.addSubstitution(in, NodeManager::currentNM()->mkConst<bool>(true));
} else {
return SOLVE_STATUS_UNSOLVED;
}
}
return SOLVE_STATUS_SOLVED;
}
}/* CVC4::theory::booleans namespace */
}/* CVC4::theory namespace */
}/* CVC4 namespace */
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