use utf8.RuneCountInString

Author: pakohan

diffmatchpatch/diff.go

@@ -670,16 +670,16 @@ func (dmp *DiffMatchPatch) DiffCleanupSemantic(diffs []Diff) []Diff {
 			// An insertion or deletion.
 
 			if diffs[pointer].Type == DiffInsert {
-				lengthInsertions2 += len([]rune(diffs[pointer].Text))
+				lengthInsertions2 += utf8.RuneCountInString(diffs[pointer].Text)
 			} else {
-				lengthDeletions2 += len([]rune(diffs[pointer].Text))
+				lengthDeletions2 += utf8.RuneCountInString(diffs[pointer].Text)
 			}
 			// Eliminate an equality that is smaller or equal to the edits on both sides of it.
 			difference1 := int(math.Max(float64(lengthInsertions1), float64(lengthDeletions1)))
 			difference2 := int(math.Max(float64(lengthInsertions2), float64(lengthDeletions2)))
-			if len([]rune(lastequality)) > 0 &&
-				(len([]rune(lastequality)) <= difference1) &&
-				(len([]rune(lastequality)) <= difference2) {
+			if utf8.RuneCountInString(lastequality) > 0 &&
+				(utf8.RuneCountInString(lastequality) <= difference1) &&
+				(utf8.RuneCountInString(lastequality) <= difference2) {
 				// Duplicate record.
 				insPoint := equalities[len(equalities)-1]
 				diffs = splice(diffs, insPoint, 0, Diff{DiffDelete, lastequality})
@@ -728,8 +728,8 @@ func (dmp *DiffMatchPatch) DiffCleanupSemantic(diffs []Diff) []Diff {
 			overlapLength1 := dmp.DiffCommonOverlap(deletion, insertion)
 			overlapLength2 := dmp.DiffCommonOverlap(insertion, deletion)
 			if overlapLength1 >= overlapLength2 {
-				if float64(overlapLength1) >= float64(len([]rune(deletion)))/2 ||
-					float64(overlapLength1) >= float64(len([]rune(insertion)))/2 {
+				if float64(overlapLength1) >= float64(utf8.RuneCountInString(deletion))/2 ||
+					float64(overlapLength1) >= float64(utf8.RuneCountInString(insertion))/2 {
 
 					// Overlap found. Insert an equality and trim the surrounding edits.
 					diffs = splice(diffs, pointer, 0, Diff{DiffEqual, insertion[:overlapLength1]})
@@ -739,8 +739,8 @@ func (dmp *DiffMatchPatch) DiffCleanupSemantic(diffs []Diff) []Diff {
 					pointer++
 				}
 			} else {
-				if float64(overlapLength2) >= float64(len([]rune(deletion)))/2 ||
-					float64(overlapLength2) >= float64(len([]rune(insertion)))/2 {
+				if float64(overlapLength2) >= float64(utf8.RuneCountInString(deletion))/2 ||
+					float64(overlapLength2) >= float64(utf8.RuneCountInString(insertion))/2 {
 					// Reverse overlap found. Insert an equality and swap and trim the surrounding edits.
 					overlap := Diff{DiffEqual, deletion[:overlapLength2]}
 					diffs = splice(diffs, pointer, 0, overlap)