/// <summary> Creates a new set relation. </summary>
/// <param name="leftOperand"> The first set in the relation (order only matters for the containment relation, in which case this is the smaller (or equal) set). </param>
/// <param name="rightOperand"> The second set in the relation (order only matters for the containment relation, in which case this is the larger (or equal) set).</param>
/// <param name="relation"> The relation conveyed by this instance that the two specified sets have. </param>
public SetRelation(Set leftOperand, Set rightOperand, SetRelationType relation)
{
Contract.Requires(leftOperand != null);
Contract.Requires(rightOperand != null);
Contract.RequiresEnumIsDefined(relation);
LeftOperand = leftOperand;
RightOperand = rightOperand;
Relation = relation;
}
public override void Add(SetRelationType relation, Set lhs, Set rhs)
{
Contract.Requires(lhs != null);
Contract.Requires(rhs != null);
Contract.Requires(lhs.IsConstant);
Contract.Requires(rhs.IsConstant);
Contract.RequiresEnumIsDefined(relation);
SetRelations.Add(lhs, rhs, relation);
}
/// <summary> Checks whether the two specified sets have the specified relation. Doesn't work for containment. </summary>
private bool CheckRelation(Set firstSet, Set secondSet, SetRelationType relation)
{
Contract.Requires(firstSet != null);
Contract.Requires(secondSet != null);
Contract.RequiresEnumIsDefined(relation);
//allows empty sets
if (firstSet == DefaultNotions.EmptySet)
return relation == SetRelationType.Subset;
if (secondSet == DefaultNotions.EmptySet)
return relation == SetRelationType.Disjoint;
if (firstSet == DefaultNotions.Unknown)
return true;
if (secondSet == DefaultNotions.Unknown)
return false;
bool result = this.relations[firstSet][secondSet] == relation;
#if DEBUG
if (relation.IsAnyOf(SetRelationType.Unknown, SetRelationType.Disjoint))
{
bool otherResult = this.relations[secondSet][firstSet] == relation;
Contract.Assert(result == otherResult, "Relation." + relation.ToString() + " isn't stored symmetrically");
}
#endif
return result;
}
/// <summary> Adds the specified set relation to the knowledge of this set relations tracker. </summary>
public void Add(Set lhs, Set rhs, SetRelationType relation)
{
Contract.Requires(lhs != null);
Contract.Requires(rhs != null);
Contract.Requires(lhs.IsConstant);
Contract.Requires(rhs.IsConstant);
Contract.RequiresEnumIsDefined(relation);
switch (relation)
{
case SetRelationType.Disjoint:
AddNoOverlapRelation(lhs, rhs);
break;
case SetRelationType.Overlap:
AddOverlapRelation(lhs, rhs);
break;
case SetRelationType.Subset:
AddSubsetRelation(lhs, rhs);
break;
case SetRelationType.Unknown:
throw new NotImplementedException();
default:
throw new Exception();
}
}
