Add support for reverse order for ItemSketches and rename the type utility struct from SerDe to Ops

common/array_of_doubles_serde.go → common/array_of_doubles_ops.go

@@ -23,40 +23,45 @@ import (
 	"math"
 )
 
-type ArrayOfDoublesSerDe struct {
+type ArrayOfDoublesOps struct {
+	ReverseOrder bool
+
 	scratch [8]byte
 }
 
-func (f ArrayOfDoublesSerDe) Identity() float64 {
+func (f ArrayOfDoublesOps) Identity() float64 {
 	return 0
 }
 
-func (f ArrayOfDoublesSerDe) Hash(item float64) uint64 {
+func (f ArrayOfDoublesOps) Hash(item float64) uint64 {
 	binary.LittleEndian.PutUint64(f.scratch[:], math.Float64bits(item))
 	return murmur3.SeedSum64(_DEFAULT_SERDE_HASH_SEED, f.scratch[:])
 }
 
-func (f ArrayOfDoublesSerDe) LessFn() LessFn[float64] {
+func (f ArrayOfDoublesOps) CompareFn() CompareFn[float64] {
 	return func(a float64, b float64) bool {
+		if f.ReverseOrder {
+			return a > b
+		}
 		return a < b
 	}
 }
 
-func (f ArrayOfDoublesSerDe) SizeOf(item float64) int {
+func (f ArrayOfDoublesOps) SizeOf(item float64) int {
 	return 8
 }
 
-func (f ArrayOfDoublesSerDe) SizeOfMany(mem []byte, offsetBytes int, numItems int) (int, error) {
+func (f ArrayOfDoublesOps) SizeOfMany(mem []byte, offsetBytes int, numItems int) (int, error) {
 	return numItems * 8, nil
 }
 
-func (f ArrayOfDoublesSerDe) SerializeOneToSlice(item float64) []byte {
+func (f ArrayOfDoublesOps) SerializeOneToSlice(item float64) []byte {
 	bytes := make([]byte, 8)
 	binary.LittleEndian.PutUint64(bytes, math.Float64bits(item))
 	return bytes
 }
 
-func (f ArrayOfDoublesSerDe) SerializeManyToSlice(item []float64) []byte {
+func (f ArrayOfDoublesOps) SerializeManyToSlice(item []float64) []byte {
 	if len(item) == 0 {
 		return []byte{}
 	}
@@ -69,7 +74,7 @@ func (f ArrayOfDoublesSerDe) SerializeManyToSlice(item []float64) []byte {
 	return bytes
 }
 
-func (f ArrayOfDoublesSerDe) DeserializeManyFromSlice(mem []byte, offsetBytes int, numItems int) ([]float64, error) {
+func (f ArrayOfDoublesOps) DeserializeManyFromSlice(mem []byte, offsetBytes int, numItems int) ([]float64, error) {
 	if numItems == 0 {
 		return []float64{}, nil
 	}

common/array_of_longs_serde.go → common/array_of_longs_ops.go

@@ -22,40 +22,45 @@ import (
 	"github.com/twmb/murmur3"
 )
 
-type ArrayOfLongsSerDe struct {
+type ArrayOfLongsOps struct {
+	ReverseOrder bool
+
 	scratch [8]byte
 }
 
-func (f ArrayOfLongsSerDe) Identity() int64 {
+func (f ArrayOfLongsOps) Identity() int64 {
 	return 0
 }
 
-func (f ArrayOfLongsSerDe) Hash(item int64) uint64 {
+func (f ArrayOfLongsOps) Hash(item int64) uint64 {
 	binary.LittleEndian.PutUint64(f.scratch[:], uint64(item))
 	return murmur3.SeedSum64(_DEFAULT_SERDE_HASH_SEED, f.scratch[:])
 }
 
-func (f ArrayOfLongsSerDe) LessFn() LessFn[int64] {
+func (f ArrayOfLongsOps) CompareFn() CompareFn[int64] {
 	return func(a int64, b int64) bool {
+		if f.ReverseOrder {
+			return a > b
+		}
 		return a < b
 	}
 }
 
-func (f ArrayOfLongsSerDe) SizeOf(item int64) int {
+func (f ArrayOfLongsOps) SizeOf(item int64) int {
 	return 8
 }
 
-func (f ArrayOfLongsSerDe) SizeOfMany(mem []byte, offsetBytes int, numItems int) (int, error) {
+func (f ArrayOfLongsOps) SizeOfMany(mem []byte, offsetBytes int, numItems int) (int, error) {
 	return numItems * 8, nil
 }
 
-func (f ArrayOfLongsSerDe) SerializeOneToSlice(item int64) []byte {
+func (f ArrayOfLongsOps) SerializeOneToSlice(item int64) []byte {
 	bytes := make([]byte, 8)
 	binary.LittleEndian.PutUint64(bytes, uint64(item))
 	return bytes
 }
 
-func (f ArrayOfLongsSerDe) SerializeManyToSlice(item []int64) []byte {
+func (f ArrayOfLongsOps) SerializeManyToSlice(item []int64) []byte {
 	if len(item) == 0 {
 		return []byte{}
 	}
@@ -68,7 +73,7 @@ func (f ArrayOfLongsSerDe) SerializeManyToSlice(item []int64) []byte {
 	return bytes
 }
 
-func (f ArrayOfLongsSerDe) DeserializeManyFromSlice(mem []byte, offsetBytes int, numItems int) ([]int64, error) {
+func (f ArrayOfLongsOps) DeserializeManyFromSlice(mem []byte, offsetBytes int, numItems int) ([]int64, error) {
 	if numItems == 0 {
 		return []int64{}, nil
 	}

common/array_of_strings_serde.go → common/array_of_strings_ops.go

@@ -25,32 +25,36 @@ import (
 	"github.com/twmb/murmur3"
 )
 
-type ArrayOfStringsSerDe struct {
+type ArrayOfStringsOps struct {
+	ReverseOrder bool
 }
 
-func (f ArrayOfStringsSerDe) Identity() string {
+func (f ArrayOfStringsOps) Identity() string {
 	return ""
 }
 
-func (f ArrayOfStringsSerDe) Hash(item string) uint64 {
+func (f ArrayOfStringsOps) Hash(item string) uint64 {
 	datum := unsafe.Slice(unsafe.StringData(item), len(item))
 	return murmur3.SeedSum64(_DEFAULT_SERDE_HASH_SEED, datum[:])
 }
 
-func (f ArrayOfStringsSerDe) LessFn() LessFn[string] {
+func (f ArrayOfStringsOps) CompareFn() CompareFn[string] {
 	return func(a string, b string) bool {
+		if f.ReverseOrder {
+			return a > b
+		}
 		return a < b
 	}
 }
 
-func (f ArrayOfStringsSerDe) SizeOf(item string) int {
+func (f ArrayOfStringsOps) SizeOf(item string) int {
 	if len(item) == 0 {
 		return int(unsafe.Sizeof(uint32(0)))
 	}
 	return len(item) + int(unsafe.Sizeof(uint32(0)))
 }
 
-func (f ArrayOfStringsSerDe) SizeOfMany(mem []byte, offsetBytes int, numItems int) (int, error) {
+func (f ArrayOfStringsOps) SizeOfMany(mem []byte, offsetBytes int, numItems int) (int, error) {
 	if numItems <= 0 {
 		return 0, nil
 	}
@@ -71,7 +75,7 @@ func (f ArrayOfStringsSerDe) SizeOfMany(mem []byte, offsetBytes int, numItems in
 	return offset - offsetBytes, nil
 }
 
-func (f ArrayOfStringsSerDe) SerializeOneToSlice(item string) []byte {
+func (f ArrayOfStringsOps) SerializeOneToSlice(item string) []byte {
 	if len(item) == 0 {
 		return []byte{}
 	}
@@ -82,7 +86,7 @@ func (f ArrayOfStringsSerDe) SerializeOneToSlice(item string) []byte {
 	return bytesOut
 }
 
-func (f ArrayOfStringsSerDe) SerializeManyToSlice(item []string) []byte {
+func (f ArrayOfStringsOps) SerializeManyToSlice(item []string) []byte {
 	if len(item) == 0 {
 		return []byte{}
 	}
@@ -105,7 +109,7 @@ func (f ArrayOfStringsSerDe) SerializeManyToSlice(item []string) []byte {
 	return bytesOut
 }
 
-func (f ArrayOfStringsSerDe) DeserializeManyFromSlice(mem []byte, offsetBytes int, numItems int) ([]string, error) {
+func (f ArrayOfStringsOps) DeserializeManyFromSlice(mem []byte, offsetBytes int, numItems int) ([]string, error) {
 	if numItems <= 0 {
 		return []string{}, nil
 	}

common/types.go

@@ -17,12 +17,12 @@
 
 package common
 
-type LessFn[C comparable] func(C, C) bool
+type CompareFn[C comparable] func(C, C) bool
 
 type ItemSketchOp[C comparable] interface {
 	Identity() C
 	Hash(item C) uint64
-	LessFn() LessFn[C]
+	CompareFn() CompareFn[C]
 	SizeOf(item C) int
 	SizeOfMany(mem []byte, offsetBytes int, numItems int) (int, error)
 	SerializeManyToSlice(items []C) []byte

examples/frequency_example_test.go

@@ -26,7 +26,7 @@ import (
 
 func TestFrequencyItemsSketch(t *testing.T) {
 	// Create a new sketch with a maximum of 16 items
-	sketch, err := frequencies.NewFrequencyItemsSketchWithMaxMapSize[string](16, common.ArrayOfStringsSerDe{})
+	sketch, err := frequencies.NewFrequencyItemsSketchWithMaxMapSize[string](16, common.ArrayOfStringsOps{})
 	assert.NoError(t, err)
 
 	// Update the sketch with some items

examples/kll_example_test.go

@@ -27,7 +27,7 @@ import (
 
 func TestKllItemsSketch(t *testing.T) {
 	// Create a new KLL sketch
-	sketch, err := kll.NewKllItemsSketchWithDefault[string](common.ArrayOfStringsSerDe{})
+	sketch, err := kll.NewKllItemsSketchWithDefault[string](common.ArrayOfStringsOps{})
 	assert.NoError(t, err)
 
 	// Update the sketch with 1000 items