Add test code and remove unnecessary code

Author: youkidearitai

ext/mbstring/mbstring.c

@@ -3244,31 +3244,17 @@ PHP_FUNCTION(mb_levenshtein)
 			}
 			if (tmp_wchar_len_2 == 0) {
 				/* Insertion process when there is a surplus of 128 code points. */
-				for (i2 = 0; i2 < tmp_wchar_len_1 && len_2 != 0; i2++) {
-					/* for overflow */
-					if (len_2 < tmp_wchar_len_1) {
-						c0 = p1[i2] + cost_rep;
-						c1 = p1[i2 + 1] + cost_del;
-					} else {
-						c0 = p1[i2 + (len_2 - tmp_wchar_len_1)] + cost_rep;
-						c1 = p1[i2 + (len_2 - tmp_wchar_len_1) + 1] + cost_del;
-					}
+				for (i2 = 0; i2 < tmp_wchar_len_1; i2++) {
+					c0 = p1[i2 + (len_2 - tmp_wchar_len_1)] + cost_rep;
+					c1 = p1[i2 + (len_2 - tmp_wchar_len_1) + 1] + cost_del;
 					if (c1 < c0) {
 						c0 = c1;
 					}
-					if (len_2 < tmp_wchar_len_1) {
-						c2 = p2[i2] + cost_ins;
-					} else {
-						c2 = p2[i2] + cost_ins;
-					}
+					c2 = p2[i2] + cost_ins;
 					if (c2 < c0) {
 						c0 = c2;
 					}
-					if (len_2 < tmp_wchar_len_1) {
-						p2[i2 + 1] = c0;
-					} else {
-						p2[i2 + (len_2 - tmp_wchar_len_1) + 1] = c0;
-					}
+					p2[i2 + (len_2 - tmp_wchar_len_1) + 1] = c0;
 				}
 			} else {
 				for (i2 = 0; i2 < tmp_wchar_len_2; i2++) {

ext/mbstring/tests/mb_levenshtein.phpt

@@ -47,6 +47,45 @@ echo '--- 128 codepoints over Hiragana in Shift_JIS ---' . \PHP_EOL;
 $hiragana_a = mb_convert_encoding("あ", "SJIS", "UTF-8");
 $hiragana_aiu = mb_convert_encoding("あいう", "SJIS", "UTF-8");
 var_dump(mb_levenshtein(str_repeat($hiragana_a, 128 + 3), str_repeat($hiragana_a, 128) . $hiragana_aiu, encoding: "SJIS"));
+
+echo '--- Usecase of userland code ---' . \PHP_EOL;
+/* from: https://qiita.com/mpyw/items/2b636827730e06c71e3d */
+$query = 'ほあようごぁいまーしゅ';
+$comps = [
+	'こんにちはー',
+	'おはようございまーす',
+	'こんばんはー',
+	'おやすみなさーい',
+	'いただきまーす',
+	'おつかれさまー',
+	'ぬぁあああんつかれたもぉぉぉぉぉぉん',
+];
+$min = 99999;
+$min_key = 0;
+foreach ($comps as $key => $comp) {
+	$sim = mb_levenshtein($query, $comp);
+	if ($min >= $sim) {
+		$min = $sim;
+		$min_key = $key;
+	}
+}
+var_dump($comps[$min_key]);
+
+$base = 'やんほぬ';
+$comps = [
+	'かんのみほ',
+	'かんのみほう',
+	'かんぺみろ',
+	'ああいいふろ',
+	'ちゃんとみろ',
+	'ターミナルさん',
+];
+foreach ($comps as $comp) {
+	var_dump(mb_levenshtein($base, $comp));
+}
+
+/* from: https://qiita.com/suin/items/a0a8227addad11ff2ea7 */
+var_dump(mb_levenshtein('あとうかい', 'かとうあい')); // int(2)
 ?>
 --EXPECT--
 --- Equal ---
@@ -84,3 +123,12 @@ int(130)
 int(2)
 --- 128 codepoints over Hiragana in Shift_JIS ---
 int(2)
+--- Usecase of userland code ---
+string(30) "おはようございまーす"
+int(4)
+int(4)
+int(4)
+int(6)
+int(5)
+int(7)
+int(2)