title: How to pack ARGB to one integer uniquely?
body: <p>I have four integer values (0 - 255) for an ARGB color map.</p>
  
  <p>Now I want to make a unique float or integer of these four integers. Is it possible to do it like the following?</p>
  
  <pre><code>sum  = 4 * 255 + A;
  sum += 3 * 255 + R;
  sum += 2 * 255 + G;
  sum += 1 * 255 + B;
  </code></pre>
  
  <p>Is the value really unique? </p>