ef: add .Has() method (#19436)

Author: AskAlexSharov

db/recsplit/eliasfano32/elias_fano_test.go

@@ -269,6 +269,11 @@ func TestEliasFano(t *testing.T) {
 	assert.Equal(t, ef2.Max(), Max(buf.Bytes()))
 	assert.Equal(t, ef2.Min(), Min(buf.Bytes()))
 	assert.Equal(t, ef2.Count(), Count(buf.Bytes()))
+
+	ref := RebasedEliasFano{}
+	ref.Reset(1000, buf.Bytes())
+	assert.True(t, ref.Has(1037))
+	assert.False(t, ref.Has(1038))
 }
 
 func BenchmarkRead(b *testing.B) {

db/recsplit/eliasfano32/rebased_elias_fano.go

@@ -46,6 +46,11 @@ func (ref *RebasedEliasFano) Seek(v uint64) (uint64, bool) {
 	return ref.baseNum + n, found
 }
 
+func (ref *RebasedEliasFano) Has(v uint64) bool {
+	n, ok := ref.Seek(v)
+	return ok && n == v
+}
+
 func (ref *RebasedEliasFano) Iterator() *RebasedIterWrapper {
 	it := &RebasedIterWrapper{}
 	it.Reset(ref, false)

db/recsplit/multiencseq/sequence_reader.go

@@ -151,6 +151,11 @@ func (s *SequenceReader) Seek(v uint64) (uint64, bool) {
 	panic(fmt.Sprintf("unknown sequence encoding: %d", s.currentEnc))
 }
 
+func (s *SequenceReader) Has(v uint64) bool {
+	n, ok := s.Seek(v)
+	return ok && n == v
+}
+
 func (s *SequenceReader) Iterator(from int) stream.U64 {
 	switch s.currentEnc {
 	case SimpleEncoding:

db/recsplit/multiencseq/sequence_reader_test.go

@@ -211,6 +211,9 @@ func requireSequenceChecks(t *testing.T, s *SequenceReader) {
 	// check reverse iterator + seek before base num
 	it = s.ReverseIterator(999)
 	require.False(t, it.HasNext())
+
+	require.True(t, s.Has(1015))
+	require.False(t, s.Has(1014))
 }
 
 func requireRawDataChecks(t *testing.T, b []byte) {

db/recsplit/simpleseq/simple_sequence.go

@@ -117,6 +117,11 @@ func (s *SimpleSequence) Seek(v uint64) (uint64, bool) {
 	return s.Get(uint64(idx)), true
 }
 
+func (s *SimpleSequence) Has(v uint64) bool {
+	n, ok := s.Seek(v)
+	return ok && n == v
+}
+
 func (s *SimpleSequence) Iterator() *SimpleSequenceIterator {
 	return &SimpleSequenceIterator{
 		seq: s,

db/recsplit/simpleseq/simple_sequence_test.go

@@ -69,6 +69,9 @@ func TestSimpleSequence(t *testing.T) {
 		v, found = s.Seek(1028)
 		require.False(t, found)
 		require.Equal(t, uint64(0), v)
+
+		require.True(t, s.Has(1007))
+		require.False(t, s.Has(1008))
 	})
 
 	t.Run("iterator", func(t *testing.T) {