title: NSString containing hex convert to ascii equivalent
body: <p>I have an NSString that has hex information such as</p>
  
  <pre><code>&lt;00000020 66747970 4d344120 00000000 4d344120 6d703432 69736f6d 00000000 00031203
  </code></pre>
  
  <p>which came from NSData. What I need to do is convert that NSString of Hex data to Ascii which would be:</p>
  
  <pre><code>[0][0][0] ftypM4A [0][0][0][0]M4A mp42isom[0][0][0][0][0][3][18][3] 
  </code></pre>
  
  <p>As you might be able to tell this is a M4A file. I loaded the first part of the file in to NSData using NSFileHandle. I then stored it into NSString:</p>
  
  <pre><code>NSData *data = [filehandle readDataOfLength:1000];
  NSString *str = [[NSString alloc]initWithString:[NSString stringWithFormat:@"%@",data]];
  </code></pre>
  
  <p>Anyone know how to convert NSData directly or convert the NSString to ascii? Thanks! </p>