removed endpoint.Diff + added xslices.{Transform,Diff}

Author: asmyasnikov

internal/endpoint/diff.go

@@ -0,0 +1,41 @@
+package xslices
+
+import (
+	"github.com/ydb-platform/ydb-go-sdk/v3/internal/xmath"
+)
+
+func Diff[T any](from, to []T, cmp func(lhs, rhs T) int) (steady, added, dropped []T) {
+	steady = make([]T, 0, xmath.Min(len(to), len(from)))
+	added = make([]T, 0, len(to))
+	dropped = make([]T, 0, len(from))
+
+	to = Sort(to, cmp)
+	from = Sort(from, cmp)
+
+	for i, j := 0, 0; ; {
+		switch {
+		case i == len(from) && j == len(to):
+			return steady, added, dropped
+		case i == len(from) && j < len(to):
+			added = append(added, to[j])
+			j++
+		case i < len(from) && j == len(to):
+			dropped = append(dropped, from[i])
+			i++
+		default:
+			cmp := cmp(from[i], to[j])
+			switch {
+			case cmp < 0:
+				dropped = append(dropped, from[i])
+				i++
+			case cmp > 0:
+				added = append(added, to[j])
+				j++
+			default:
+				steady = append(steady, from[i])
+				i++
+				j++
+			}
+		}
+	}
+}

internal/endpoint/diff_test.go

@@ -0,0 +1,145 @@
+package xslices
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestDiff(t *testing.T) {
+	for _, tt := range []struct {
+		name     string
+		previous []int
+		newest   []int
+		steady   []int
+		added    []int
+		dropped  []int
+	}{
+		{
+			name: "WithoutChanges",
+			previous: []int{
+				2,
+				1,
+				0,
+				3,
+			},
+			newest: []int{
+				1,
+				3,
+				2,
+				0,
+			},
+			steady: []int{
+				0,
+				1,
+				2,
+				3,
+			},
+			added:   []int{},
+			dropped: []int{},
+		},
+		{
+			name: "OnlyAdded",
+			previous: []int{
+				1,
+				0,
+				3,
+			},
+			newest: []int{
+				1,
+				3,
+				2,
+				0,
+			},
+			steady: []int{
+				0,
+				1,
+				3,
+			},
+			added: []int{
+				2,
+			},
+			dropped: []int{},
+		},
+		{
+			name: "OnlyDropped",
+			previous: []int{
+				1,
+				2,
+				0,
+				3,
+			},
+			newest: []int{
+				1,
+				3,
+				0,
+			},
+			steady: []int{
+				0,
+				1,
+				3,
+			},
+			added: []int{},
+			dropped: []int{
+				2,
+			},
+		},
+		{
+			name: "AddedAndDropped1",
+			previous: []int{
+				4,
+				7,
+				8,
+			},
+			newest: []int{
+				1,
+				3,
+				0,
+			},
+			steady: []int{},
+			added: []int{
+				0,
+				1,
+				3,
+			},
+			dropped: []int{
+				4,
+				7,
+				8,
+			},
+		},
+		{
+			name: "AddedAndDropped2",
+			previous: []int{
+				1,
+				3,
+				0,
+			},
+			newest: []int{
+				4,
+				7,
+				8,
+			},
+			steady: []int{},
+			added: []int{
+				4,
+				7,
+				8,
+			},
+			dropped: []int{
+				0,
+				1,
+				3,
+			},
+		},
+	} {
+		t.Run(tt.name, func(t *testing.T) {
+			steady, added, dropped := Diff(tt.previous, tt.newest, func(lhs, rhs int) int {
+				return lhs - rhs
+			})
+			require.Equal(t, tt.added, added)
+			require.Equal(t, tt.dropped, dropped)
+			require.Equal(t, tt.steady, steady)
+		})
+	}
+}

internal/xslices/diff.go

@@ -0,0 +1,16 @@
+//go:build go1.21
+// +build go1.21
+
+package xslices
+
+import (
+	"slices"
+)
+
+func Sort[T any](in []T, cmp func(lhs, rhs T) int) (out []T) {
+	out = Clone(in)
+
+	slices.SortFunc(out, cmp)
+
+	return out
+}

internal/xslices/diff_test.go

@@ -0,0 +1,18 @@
+//go:build !go1.21
+// +build !go1.21
+
+package xslices
+
+import (
+	"sort"
+)
+
+func Sort[T any](in []T, cmp func(lhs, rhs T) int) (out []T) {
+	out = Clone(in)
+
+	sort.Slice(out, func(i, j int) bool {
+		return cmp(out[i], out[j]) < 0
+	})
+
+	return out
+}