public static void addConstantConstraint(
Map<Var, NodeValue> map, Pair<Var, NodeValue> constraint) {
if (constraint == null) {
return;
}
addConstantConstraint(map, constraint.getKey(), constraint.getValue());
}
/**
* For each clause determine the constant constraints, and return those, that are common to all
* clauses.
*
* @param dnf
*/
public static Map<Var, NodeValue> extractConstantConstraints(Set<Set<Expr>> dnf) {
Map<Var, NodeValue> result = new HashMap<Var, NodeValue>();
Iterator<Set<Expr>> clauseIt = dnf.iterator();
if (!clauseIt.hasNext()) {
return result;
}
Set<Expr> firstClause = clauseIt.next();
for (Expr expr : firstClause) {
Pair<Var, NodeValue> constraint = ExprUtils.extractConstantConstraint(expr);
addConstantConstraint(result, constraint);
}
Set<Var> seenVars = new HashSet<Var>();
while (clauseIt.hasNext()) {
if (result.isEmpty()) {
return result;
}
Set<Expr> clause = clauseIt.next();
for (Expr expr : clause) {
Pair<Var, NodeValue> constraint = ExprUtils.extractConstantConstraint(expr);
if (constraint == null || !result.containsKey(constraint.getKey())) {
continue;
}
addConstantConstraint(result, constraint);
seenVars.add(constraint.getKey());
}
result.keySet().retainAll(seenVars);
seenVars.clear();
}
return result;
}