title: Get offset of a file, using 5 characters of a custom dictionary
body: <p>I want to get a string offset of file, but the string offset changes file to file.
  So, I did make a custom dictionary.</p>
  <pre><code>        [0x41] = &quot;A&quot;,
          [0x42] = &quot;B&quot;,
          [0x43] = &quot;C&quot;,
          [0x44] = &quot;D&quot;,
          [0x45] = &quot;E&quot;,
          [0x46] = &quot;F&quot;,
          [0x47] = &quot;G&quot;,
  </code></pre>
  <p>.....................
  To get the offset, i want to read the file, when finds 5 sequential chars of my dictionary, stop then back -5 and then get offset.</p>
  <p>Can someone help me?</p>