diff --git a/internal/diff/ndiff.go b/internal/diff/ndiff.go
new file mode 100644
index 0000000..e537b72
--- /dev/null
+++ b/internal/diff/ndiff.go
@@ -0,0 +1,130 @@
+// Copyright 2022 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package diff
+
+import (
+	"strings"
+	"unicode/utf8"
+
+	"golang.org/x/tools/internal/diff/lcs"
+	"golang.org/x/tools/internal/span"
+)
+
+// maxDiffs is a limit on how deeply the lcs algorithm should search
+// the value is just a guess
+const maxDiffs = 30
+
+// NComputeEdits computes TextEdits for strings
+// (both it and the diff in the myers package have type ComputeEdits, which
+// is why the arguments are strings, not []bytes.)
+func NComputeEdits(uri span.URI, before, after string) ([]TextEdit, error) {
+	if before == after {
+		// very frequently true
+		return nil, nil
+	}
+	// the diffs returned by the lcs package use indexes into whatever slice
+	// was passed in. TextEdits  need a span.Span which is computed with
+	// byte offsets, so rune or line offsets need to be converted.
+	if needrunes(before) || needrunes(after) {
+		diffs, _ := lcs.Compute([]rune(before), []rune(after), maxDiffs/2)
+		diffs = runeOffsets(diffs, []rune(before))
+		ans, err := convertDiffs(uri, diffs, []byte(before))
+		return ans, err
+	} else {
+		diffs, _ := lcs.Compute([]byte(before), []byte(after), maxDiffs/2)
+		ans, err := convertDiffs(uri, diffs, []byte(before))
+		return ans, err
+	}
+}
+
+// NComputeLineEdits computes TextEdits for []strings
+func NComputeLineEdits(uri span.URI, before, after []string) ([]TextEdit, error) {
+	diffs, _ := lcs.Compute(before, after, maxDiffs/2)
+	diffs = lineOffsets(diffs, before)
+	ans, err := convertDiffs(uri, diffs, []byte(strJoin(before)))
+	// the code is not coping with possible missing \ns at the ends
+	return ans, err
+}
+
+// convert diffs with byte offsets into diffs with line and column
+func convertDiffs(uri span.URI, diffs []lcs.Diff, src []byte) ([]TextEdit, error) {
+	ans := make([]TextEdit, len(diffs))
+	tf := span.NewTokenFile(uri.Filename(), src)
+	for i, d := range diffs {
+		s := newSpan(uri, d.Start, d.End)
+		s, err := s.WithPosition(tf)
+		if err != nil {
+			return nil, err
+		}
+		ans[i] = TextEdit{s, d.Text}
+	}
+	return ans, nil
+}
+
+// convert diffs with rune offsets into diffs with byte offsets
+func runeOffsets(diffs []lcs.Diff, src []rune) []lcs.Diff {
+	var idx int
+	var tmp strings.Builder // string because []byte([]rune) is illegal
+	for i, d := range diffs {
+		tmp.WriteString(string(src[idx:d.Start]))
+		v := tmp.Len()
+		tmp.WriteString(string(src[d.Start:d.End]))
+		d.Start = v
+		idx = d.End
+		d.End = tmp.Len()
+		diffs[i] = d
+	}
+	return diffs
+}
+
+// convert diffs with line offsets into diffs with byte offsets
+func lineOffsets(diffs []lcs.Diff, src []string) []lcs.Diff {
+	var idx int
+	var tmp strings.Builder // bytes/
+	for i, d := range diffs {
+		tmp.WriteString(strJoin(src[idx:d.Start]))
+		v := tmp.Len()
+		tmp.WriteString(strJoin(src[d.Start:d.End]))
+		d.Start = v
+		idx = d.End
+		d.End = tmp.Len()
+		diffs[i] = d
+	}
+	return diffs
+}
+
+// join lines. (strings.Join doesn't add a trailing separator)
+func strJoin(elems []string) string {
+	if len(elems) == 0 {
+		return ""
+	}
+	n := 0
+	for i := 0; i < len(elems); i++ {
+		n += len(elems[i])
+	}
+
+	var b strings.Builder
+	b.Grow(n)
+	for _, s := range elems {
+		b.WriteString(s)
+		//b.WriteByte('\n')
+	}
+	return b.String()
+}
+
+func newSpan(uri span.URI, left, right int) span.Span {
+	return span.New(uri, span.NewPoint(0, 0, left), span.NewPoint(0, 0, right))
+}
+
+// need runes is true if the string needs to be converted to []rune
+// for random access
+func needrunes(s string) bool {
+	for i := 0; i < len(s); i++ {
+		if s[i] >= utf8.RuneSelf {
+			return true
+		}
+	}
+	return false
+}