Exposed DiffLinesToRunes and did other minor cleanup.

If clients clients use DiffLinesToRunes they can avoid an extra string to rune conversion.

Also fixed some comments and got rid of an unnecessary helper function.

Author: jba

diffmatchpatch/dmp.go

@@ -245,18 +245,22 @@ func (dmp *DiffMatchPatch) DiffMain(text1, text2 string, checklines bool) []Diff
 	return dmp.diffMain(text1, text2, checklines, deadline)
 }
 
-// DiffMain finds the differences between two rune sequences.
 func (dmp *DiffMatchPatch) diffMain(text1, text2 string, checklines bool, deadline time.Time) []Diff {
-	diffs := []Diff{}
-	if text1 == text2 {
-		if len(text1) > 0 {
-			diffs = append(diffs, Diff{DiffEqual, text1})
-		}
-		return diffs
+	return dmp.diffMainRunes([]rune(text1), []rune(text2), checklines, deadline)
+}
+
+// DiffMainRunes finds the differences between two rune sequences.
+func (dmp *DiffMatchPatch) DiffMainRunes(text1, text2 []rune, checklines bool) []Diff {
+	var deadline time.Time
+	if dmp.DiffTimeout <= 0 {
+		deadline = time.Now().Add(24 * 365 * time.Hour)
+	} else {
+		deadline = time.Now().Add(dmp.DiffTimeout)
 	}
-	return dmp.diffMainRunes1([]rune(text1), []rune(text2), checklines, deadline)
+	return dmp.diffMainRunes(text1, text2, checklines, deadline)
 }
 
+
 func (dmp *DiffMatchPatch) diffMainRunes(text1, text2 []rune, checklines bool, deadline time.Time) []Diff {
 	if runesEqual(text1, text2) {
 		var diffs []Diff
@@ -265,11 +269,6 @@ func (dmp *DiffMatchPatch) diffMainRunes(text1, text2 []rune, checklines bool, d
 		}
 		return diffs
 	}
-	return dmp.diffMainRunes1(text1, text2, checklines, deadline)
-}
-
-
-func (dmp *DiffMatchPatch) diffMainRunes1(text1, text2 []rune, checklines bool, deadline time.Time) []Diff {
 	// Trim off common prefix (speedup).
 	commonlength := commonPrefixLength(text1, text2)
 	commonprefix := text1[:commonlength]
@@ -418,9 +417,13 @@ func (dmp *DiffMatchPatch) diffLineMode(text1, text2 []rune, deadline time.Time)
 // and return the recursively constructed diff.
 // See Myers 1986 paper: An O(ND) Difference Algorithm and Its Variations.
 func (dmp *DiffMatchPatch) DiffBisect(text1, text2 string, deadline time.Time) []Diff {
+	// Unused in this code, but retained for interface compatibility.
 	return dmp.diffBisect([]rune(text1), []rune(text2), deadline)
 }
 
+// diffBisect finds the 'middle snake' of a diff, splits the problem in two
+// and returns the recursively constructed diff.
+// See Myers's 1986 paper: An O(ND) Difference Algorithm and Its Variations.
 func (dmp *DiffMatchPatch) diffBisect(text1, text2 []rune, deadline time.Time) []Diff {
 	// Cache the text lengths to prevent multiple calls.
 	runes1_len, runes2_len := len(runes1), len(runes2)
@@ -560,8 +563,7 @@ func (dmp *DiffMatchPatch) DiffLinesToChars(text1, text2 string) (string, string
 	return string(chars1), string(chars2), lineArray
 }
 
-// DiffLinesToChars split two texts into a list of []runes.  Reduces the texts to a string of
-// hashes where each Unicode character represents one line.
+// DiffLinesToRunes splits two texts into a list of runes.  Each rune represents one line.
 func (dmp *DiffMatchPatch) DiffLinesToRunes(text1, text2 string) ([]rune, []rune, []string) {
 	// '\x00' is a valid character, but various debuggers don't like it.
 	// So we'll insert a junk entry to avoid generating a null character.

diffmatchpatch/dmp_test.go

@@ -1434,8 +1434,8 @@ func Benchmark_DiffMainLargeLines(b *testing.B) {
 	dmp := New()
 	b.ResetTimer()
 	for i := 0; i < b.N; i++ {
-		text1, text2, linearray := dmp.DiffLinesToChars(s1, s2)
-		diffs := dmp.DiffMain(text1, text2, false)
+		text1, text2, linearray := dmp.DiffLinesToRunes(s1, s2)
+		diffs := dmp.DiffMainRunes(text1, text2, false)
 		diffs = dmp.DiffCharsToLines(diffs, linearray)
 	}
 }