title: Bit Flag dependencies in Sulley Fuzzing Framework
body: <p>I'm trying to build a Fuzzer with Sulley. The protocol I'm using has a one byte <code>control</code> field. the bits which are set in this field determine which fields can follow. Now I'm wondering how to implement this behaviour using the <code>dep</code> parameters in Sulley. The only <code>dep_compare</code> operators available are <code>"==, !=, &gt;, &gt;=, &lt;, &lt;="</code>, but I don't think I can check whether a bit is set in another field with those operators. So how could I do this?</p>
  
  <pre><code>s_byte(0b1000000, "control_field")
  
  # The following block shall be present if bit 7 is set in control_field
  # I'd like to use something like 
  # &gt; control_field &amp; 0b1000000 != 0 
  # but I don't know how
  
  if s_block_start("something_optional", dep="control_field", dep_compare="?"):
      s_short(0x1234, "optional")
  s_block_end()
  </code></pre>