title: Conversion of Unicode >> U+9FFF to form URLs
body: <p>Trying to convert strings that contain an escaped unicode (ex: \u3400) in the range of U+20000 to U+2B81F to form URLs, but it's not working. The range U+3400 to U+9FFF works just fine.</p>
  
  <pre><code>NSString *string1 = @"\u9FFF";
  string1 = [string1 stringByReplacingPercentEscapesUsingEncoding:NSUnicodeStringEncoding];
  NSURL *url1 = [NSURL URLWithString:[NSString stringWithFormat:@"http://en.wikipedia.org/Search?search=%@", string1]];
  NSLog(@"url1: %@", url1);
  </code></pre>
  
  <p><strong>OUTPUT</strong>: url1: <a href="http://en.wikipedia.org/Search?search=%E9%BF%BF" rel="nofollow">http://en.wikipedia.org/Search?search=%E9%BF%BF</a></p>
  
  <pre><code>NSString *string2 = @"\u20000";
  string2 = [string2 stringByReplacingPercentEscapesUsingEncoding:NSUnicodeStringEncoding];
  NSURL *url2 = [NSURL URLWithString:[NSString stringWithFormat:@"http://en.wikipedia.org/Search?search=%@", string2]];
  NSLog(@"url2: %@", url2);
  </code></pre>
  
  <p><strong>OUTPUT</strong>: url2: (null)</p>
  
  <p>Basically, what I want is to convert a list of escaped unicodes (\u3400 to \u2B81F) to URLs (or even NSStrings). If there is another way to achieve this by other string conversion means, I'll be thankful.</p>