// Intersects reports whether this points-to set and the
// argument points-to set contain common members.
func (x PointsToSet) Intersects(y PointsToSet) bool {
if x.pts == nil || y.pts == nil {
return false
}
// This takes Θ(|x|+|y|) time.
var z intsets.Sparse
z.Intersection(&x.pts.Sparse, &y.pts.Sparse)
return !z.IsEmpty()
}
func BenchmarkAppendTo(b *testing.B) {
prng := rand.New(rand.NewSource(0))
var x intsets.Sparse
for i := 0; i < 1000; i++ {
x.Insert(int(prng.Int()) % 10000)
}
var space [1000]int
for tries := 0; tries < b.N; tries++ {
x.AppendTo(space[:0])
}
}
func TestFailFastOnShallowCopy(t *testing.T) {
var x intsets.Sparse
x.Insert(1)
y := x // shallow copy (breaks representation invariants)
defer func() {
got := fmt.Sprint(recover())
want := "A Sparse has been copied without (*Sparse).Copy()"
if got != want {
t.Errorf("shallow copy: recover() = %q, want %q", got, want)
}
}()
y.String() // panics
t.Error("didn't panic as expected")
}
func TestBitString(t *testing.T) {
for _, test := range []struct {
input []int
want string
}{
{nil, "0"},
{[]int{0}, "1"},
{[]int{0, 4, 5}, "110001"},
{[]int{0, 7, 177}, "1" + strings.Repeat("0", 169) + "10000001"},
{[]int{-3, 0, 4, 5}, "110001.001"},
{[]int{-3}, "0.001"},
} {
var set intsets.Sparse
for _, x := range test.input {
set.Insert(x)
}
if got := set.BitString(); got != test.want {
t.Errorf("BitString(%s) = %s, want %s", set.String(), got, test.want)
}
}
}
func TestIntersects(t *testing.T) {
prng := rand.New(rand.NewSource(0))
for i := uint(0); i < 12; i++ {
X, Y := randomPset(prng, 1<<i), randomPset(prng, 1<<i)
x, y := &X.bits, &Y.bits
// test the slow way
var z intsets.Sparse
z.Copy(x)
z.IntersectionWith(y)
if got, want := x.Intersects(y), !z.IsEmpty(); got != want {
t.Errorf("Intersects: got %v, want %v", got, want)
}
// make it false
a := x.AppendTo(nil)
for _, v := range a {
y.Remove(v)
}
if got, want := x.Intersects(y), false; got != want {
t.Errorf("Intersects: got %v, want %v", got, want)
}
// make it true
if x.IsEmpty() {
continue
}
i := prng.Intn(len(a))
y.Insert(a[i])
if got, want := x.Intersects(y), true; got != want {
t.Errorf("Intersects: got %v, want %v", got, want)
}
}
}
func TestSubsetOf(t *testing.T) {
prng := rand.New(rand.NewSource(0))
for i := uint(0); i < 12; i++ {
X, Y := randomPset(prng, 1<<i), randomPset(prng, 1<<i)
x, y := &X.bits, &Y.bits
// test the slow way
var z intsets.Sparse
z.Copy(x)
z.DifferenceWith(y)
if got, want := x.SubsetOf(y), z.IsEmpty(); got != want {
t.Errorf("SubsetOf: got %v, want %v", got, want)
}
// make it true
y.UnionWith(x)
if got, want := x.SubsetOf(y), true; got != want {
t.Errorf("SubsetOf: got %v, want %v", got, want)
}
// make it false
if x.IsEmpty() {
continue
}
a := x.AppendTo(nil)
i := prng.Intn(len(a))
y.Remove(a[i])
if got, want := x.SubsetOf(y), false; got != want {
t.Errorf("SubsetOf: got %v, want %v", got, want)
}
}
}
func TestTakeMin(t *testing.T) {
var set intsets.Sparse
set.Insert(456)
set.Insert(123)
set.Insert(789)
set.Insert(-123)
var got int
for i, want := range []int{-123, 123, 456, 789} {
if !set.TakeMin(&got) || got != want {
t.Errorf("TakeMin #%d: got %d, want %d", i, got, want)
}
}
if set.TakeMin(&got) {
t.Errorf("%s.TakeMin returned true", &set)
}
if err := set.Check(); err != nil {
t.Fatalf("check: %s: %#v", err, &set)
}
}
// Insert, Len, IsEmpty, Hash, Clear, AppendTo.
func TestMoreBasics(t *testing.T) {
set := new(intsets.Sparse)
set.Insert(456)
set.Insert(123)
set.Insert(789)
if set.Len() != 3 {
t.Errorf("%s.Len: got %d, want 3", set, set.Len())
}
if set.IsEmpty() {
t.Errorf("%s.IsEmpty: got true", set)
}
if !set.Has(123) {
t.Errorf("%s.Has(123): got false", set)
}
if set.Has(1234) {
t.Errorf("%s.Has(1234): got true", set)
}
got := set.AppendTo([]int{-1})
if want := []int{-1, 123, 456, 789}; fmt.Sprint(got) != fmt.Sprint(want) {
t.Errorf("%s.AppendTo: got %v, want %v", set, got, want)
}
set.Clear()
if set.Len() != 0 {
t.Errorf("Clear: got %d, want 0", set.Len())
}
if !set.IsEmpty() {
t.Errorf("IsEmpty: got false")
}
if set.Has(123) {
t.Errorf("%s.Has: got false", set)
}
}
func BenchmarkSparseBitVector(b *testing.B) {
prng := rand.New(rand.NewSource(0))
for tries := 0; tries < b.N; tries++ {
var x, y, z intsets.Sparse
for i := 0; i < 1000; i++ {
n := int(prng.Int()) % 100000
if i%2 == 0 {
x.Insert(n)
} else {
y.Insert(n)
}
}
z.Union(&x, &y)
z.Difference(&x, &y)
}
}
func TestIntersectionWith(t *testing.T) {
// Edge cases: the pairs (1,1), (1000,2000), (8000,4000)
// exercise the <, >, == cases in IntersectionWith that the
// TestSetOperations data is too dense to cover.
var X, Y intsets.Sparse
X.Insert(1)
X.Insert(1000)
X.Insert(8000)
Y.Insert(1)
Y.Insert(2000)
Y.Insert(4000)
X.IntersectionWith(&Y)
if got, want := X.String(), "{1}"; got != want {
t.Errorf("IntersectionWith: got %s, want %s", got, want)
}
}
func TestBasics(t *testing.T) {
var s intsets.Sparse
if len := s.Len(); len != 0 {
t.Errorf("Len({}): got %d, want 0", len)
}
if s := s.String(); s != "{}" {
t.Errorf("String({}): got %q, want \"{}\"", s)
}
if s.Has(3) {
t.Errorf("Has(3): got true, want false")
}
if err := s.Check(); err != nil {
t.Error(err)
}
if !s.Insert(3) {
t.Errorf("Insert(3): got false, want true")
}
if max := s.Max(); max != 3 {
t.Errorf("Max: got %d, want 3", max)
}
if !s.Insert(435) {
t.Errorf("Insert(435): got false, want true")
}
if s := s.String(); s != "{3 435}" {
t.Errorf("String({3 435}): got %q, want \"{3 435}\"", s)
}
if max := s.Max(); max != 435 {
t.Errorf("Max: got %d, want 435", max)
}
if len := s.Len(); len != 2 {
t.Errorf("Len: got %d, want 2", len)
}
if !s.Remove(435) {
t.Errorf("Remove(435): got false, want true")
}
if s := s.String(); s != "{3}" {
t.Errorf("String({3}): got %q, want \"{3}\"", s)
}
}
func TestEquals(t *testing.T) {
var setX intsets.Sparse
setX.Insert(456)
setX.Insert(123)
setX.Insert(789)
if !setX.Equals(&setX) {
t.Errorf("Equals(%s, %s): got false", &setX, &setX)
}
var setY intsets.Sparse
setY.Insert(789)
setY.Insert(456)
setY.Insert(123)
if !setX.Equals(&setY) {
t.Errorf("Equals(%s, %s): got false", &setX, &setY)
}
setY.Insert(1)
if setX.Equals(&setY) {
t.Errorf("Equals(%s, %s): got true", &setX, &setY)
}
var empty intsets.Sparse
if setX.Equals(&empty) {
t.Errorf("Equals(%s, %s): got true", &setX, &empty)
}
// Edge case: some block (with offset=0) appears in X but not Y.
setY.Remove(123)
if setX.Equals(&setY) {
t.Errorf("Equals(%s, %s): got true", &setX, &setY)
}
}
func TestMinAndMax(t *testing.T) {
values := []int{0, 456, 123, 789, -123} // elt 0 => empty set
wantMax := []int{intsets.MinInt, 456, 456, 789, 789}
wantMin := []int{intsets.MaxInt, 456, 123, 123, -123}
var set intsets.Sparse
for i, x := range values {
if i != 0 {
set.Insert(x)
}
if got, want := set.Min(), wantMin[i]; got != want {
t.Errorf("Min #%d: got %d, want %d", i, got, want)
}
if got, want := set.Max(), wantMax[i]; got != want {
t.Errorf("Max #%d: got %d, want %d", i, got, want)
}
}
set.Insert(intsets.MinInt)
if got, want := set.Min(), intsets.MinInt; got != want {
t.Errorf("Min: got %d, want %d", got, want)
}
set.Insert(intsets.MaxInt)
if got, want := set.Max(), intsets.MaxInt; got != want {
t.Errorf("Max: got %d, want %d", got, want)
}
}