Implement case mapping using the Unicode default case mapping algorithm.

runtime/lib/string.dart

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 /**
  * [StringBase] contains common methods used by concrete String implementations,
  * e.g., OneByteString.
  */
 class StringBase {
 
@@ skipping 316 matching lines @@
 
   Array<int> charCodes() {
     int len = this.length;
     final result = new Array<int>(len);
     for (int i = 0; i < len; i++) {
       result[i] = this.charCodeAt(i);
     }
     return result;
   }
 
-  String toLowerCase() {
-    final int aCode = "A".charCodeAt(0);
-    final int zCode = "Z".charCodeAt(0);
-    final int delta = aCode - "a".charCodeAt(0);
-    return _convert(this, aCode, zCode, delta);
-  }
+  String toUpperCase() native "String_toUpperCase";
 
-  String toUpperCase() {
-    final int aCode = "a".charCodeAt(0);
-    final int zCode = "z".charCodeAt(0);
-    final int delta = aCode - "A".charCodeAt(0);
-    return _convert(this, aCode, zCode, delta);
-  }
-
-  static String _convert(String str, int startCode, int endCode, int delta) {
-    final int len = str.length;
-    int i = 0;
-    // Check if we can just return the string.
-    for (; i < len; i++) {
-      int code = str.charCodeAt(i);
-      if ((startCode <= code) && (code <= endCode)) break;
-    }
-    if (i == len) return str;
-
-    Array<int> charCodes = new Array<int>(len);
-    for (i = 0; i < len; i++) {
-      int code = str.charCodeAt(i);
-      if ((startCode <= code) && (code <= endCode)) {
-        code = code - delta;
-      }
-      charCodes[i] = code;
-    }
-    return StringBase.createFromCharCodes(charCodes);
-  }
-
-
+  String toLowerCase() native "String_toLowerCase";
 
   // Implementations of Strings methods follow below.
   static String join(Array<String> strings, String separator) {
     final int length = strings.length;
     if (length === 0) {
       return "";
     }
 
     Array strings_array = strings;
     if (separator.length != 0) {
@@ skipping 85 matching lines @@
     for (int g in groups) {
       result.add(group(g));
     }
     return result;
   }
 
   final int _start;
   final String str;
   final String pattern;
 }