public FrozenSetCollection union([NotNull] params object[] /*!*/ sets)
{
SetStorage res = _items.Clone();
foreach (object set in sets)
{
res.UnionUpdate(SetStorage.GetItems(set));
}
return(Make(res));
}
public SetCollection intersection([NotNull] params object[] /*!*/ sets)
{
Debug.Assert(sets != null);
if (sets.Length == 0)
{
return(copy());
}
SetStorage res = _items;
foreach (object set in sets)
{
SetStorage items, x = res, y;
if (SetStorage.GetItems(set, out items))
{
y = items;
SetStorage.SortBySize(ref x, ref y);
if (object.ReferenceEquals(x, items) || object.ReferenceEquals(x, _items))
{
x = x.Clone();
}
}
else
{
y = items;
SetStorage.SortBySize(ref x, ref y);
if (object.ReferenceEquals(x, _items))
{
x = x.Clone();
}
}
x.IntersectionUpdate(y);
res = x;
}
Debug.Assert(!object.ReferenceEquals(res, _items));
return(Make(res));
}
public SetCollection copy()
{
return(Make(_items.Clone()));
}
