Improving speed and removing using Stream API.

Author: ppisl

graalpython/com.oracle.graal.python.test/src/tests/test_string.py

@@ -707,6 +707,8 @@ def test_title_uni(self):
         self.assertEqual('X\U00010427x\U0001044F X\U00010427x\U0001044F'.title(),
                          'X\U0001044Fx\U0001044F X\U0001044Fx\U0001044F')
         self.assertEqual('fiNNISH'.title(), 'Finnish')
+        self.assertEqual('bfiNNISH'.title(), 'Bfinnish')
+        self.assertEqual('fifiNNfiISH'.title(), 'Fifinnfiish')
         self.assertEqual('A\u03a3A'.title(), 'A\u03c3a')
 
 def test_same_id():

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/objects/str/StringBuiltins.java

@@ -1547,13 +1547,12 @@ abstract static class TitleNode extends PythonUnaryBuiltinNode {
         @Specialization
         @TruffleBoundary
         public String doTitle(String self) {
-            int[] codePoints = self.codePoints().toArray();
-            int len = codePoints.length;
+            int len = self.length();
             boolean shouldBeLowerCase = false;
             boolean translated;
             StringBuilder converted = new StringBuilder();
-            for (int i = 0; i < len; i++) {
-                int ch = codePoints[i];
+            for (int offset = 0; offset < self.length();) {
+                int ch = self.codePointAt(offset);
                 translated = false;
                 if (Character.isAlphabetic(ch)) {
                     if (shouldBeLowerCase) {
@@ -1599,6 +1598,7 @@ public String doTitle(String self) {
                         converted.append(Character.toChars(ch));
                     }
                 }
+                offset += Character.charCount(ch);
             }
             return converted.toString();
         }