How i can Convert this Function Back?
<pre><code>function getVideoName($in) {
    $index = "abcdefghijklmnopqrstuvwxyz0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";

    $base = strlen($index);

    // Digital number  &lt;&lt;--  alphabet letter code
    $in = strrev($in);
    $out = 0;
    $len = strlen($in) - 1;
    for ($t = 0; $t &lt;= $len; $t++) {
        $bcpow = bcpow($base, $len - $t);
        $out = $out + strpos($index, substr($in, $t, 1)) * $bcpow;
    }

    $out = sprintf('%F', $out);
    $out = substr($out, 0, strpos($out, '.'));

    return $out;

}
</code></pre>

<p>This Function return a converted value
How i can convert the value back to input number ?</p>
