/**
* Searches for expression of the form ?var = const
*
* <p>TODO We are not considering equals between variables. A space efficient way to achieve this
* is by creating a new expression, where the substitution ?x ?y has been applied.
*
* <p>?x = const . ?y = const . ?x = ?y .
*
* @param clause
* @return
*/
public static Map<Var, ValueSet<NodeValue>> extractValueConstraintsDnf(Set<Set<Expr>> dnf) {
Map<Var, ValueSet<NodeValue>> result = null;
if (dnf == null) {
return result;
}
for (Set<Expr> clause : dnf) {
Map<Var, ValueSet<NodeValue>> map = extractValueConstraintsDnfClause(clause);
if (result == null) {
result = map;
continue;
}
Iterator<Map.Entry<Var, ValueSet<NodeValue>>> itEntry = result.entrySet().iterator();
// for(Map.Entry<Var, ValueSet<NodeValue>> entry : result.entrySet()) {
while (itEntry.hasNext()) {
Map.Entry<Var, ValueSet<NodeValue>> entry = itEntry.next();
ValueSet<NodeValue> a = entry.getValue();
ValueSet<NodeValue> b = map.get(entry.getKey());
a.merge(b);
if (a.isUnknown()) {
itEntry.remove();
}
}
if (result.isEmpty()) {
break;
}
}
return (result == null) ? new HashMap<Var, ValueSet<NodeValue>>() : result;
}
