func TestSelfEqual(t *testing.T) {
s := set.NewSet()
if !set.Equal(s, s) {
t.Error("Set is not equal to itself")
}
s.Add(1)
if !set.Equal(s, s) {
t.Error("Set ceases self equality after adding element")
}
}
func TestEqual(t *testing.T) {
s1 := set.NewSet()
s2 := set.NewSet()
if !set.Equal(s1, s2) {
t.Error("Two different empty sets not equal")
}
s1.Add(1)
if set.Equal(s1, s2) {
t.Error("Two different sets with different elements not equal")
}
s2.Add(1)
if !set.Equal(s1, s2) {
t.Error("Two sets with same element not equal")
}
}
func TestCopy(t *testing.T) {
s1 := set.NewSet()
s2 := set.NewSet()
s1.Add(1)
s1.Add(2)
s1.Add(3)
s2.Copy(s1)
if !set.Equal(s1, s2) {
t.Fatalf("Two sets not equal after copy")
}
s2.Remove(1)
if set.Equal(s1, s2) {
t.Errorf("Mutating one set mutated another after copy")
}
}
// A Postdominates B if and only if all paths from B travel through A
//
// This returns all possible post-dominators for all nodes, it does not prune for strict postdominators, immediate postdominators etc
func PostDominators(end Node, graph Graph) map[int]*set.Set {
allNodes := set.NewSet()
nlist := graph.NodeList()
dominators := make(map[int]*set.Set, len(nlist))
for _, node := range nlist {
allNodes.Add(node.ID())
}
for _, node := range nlist {
dominators[node.ID()] = set.NewSet()
if node.ID() == end.ID() {
dominators[node.ID()].Add(end.ID())
} else {
dominators[node.ID()].Copy(allNodes)
}
}
for somethingChanged := true; somethingChanged; {
somethingChanged = false
for _, node := range nlist {
if node.ID() == end.ID() {
continue
}
succs := graph.Successors(node)
if len(succs) == 0 {
continue
}
tmp := set.NewSet().Copy(dominators[succs[0].ID()])
for _, succ := range succs[1:] {
tmp.Intersection(tmp, dominators[succ.ID()])
}
dom := set.NewSet()
dom.Add(node.ID())
dom.Union(dom, tmp)
if !set.Equal(dom, dominators[node.ID()]) {
dominators[node.ID()] = dom
somethingChanged = true
}
}
}
return dominators
}
