// DOCME needs phpdoc block
// TESTME needs unit testing
function short_hostname($hostname, $len = NULL, $escape = TRUE)
{
  $len = (is_numeric($len) ? (int)$len : (int)$GLOBALS['config']['short_hostname']['length']);

  if (function_exists('custom_shorthost'))
  {
    $short_hostname = custom_shorthost($hostname, $len);
  }
  else if (function_exists('custom_short_hostname'))
  {
    $short_hostname = custom_short_hostname($hostname, $len);
  } else {

    if (get_ip_version($hostname)) { return $hostname; } // If hostname is IP address, always return full hostname

    $parts = explode('.', $hostname);
    $short_hostname = $parts[0];
    $i = 1;
    while ($i < count($parts) && strlen($short_hostname.'.'.$parts[$i]) < $len)
    {
      $short_hostname = $short_hostname.'.'.$parts[$i];
      $i++;
    }
  }
  if ($escape) { $short_hostname = escape_html($short_hostname); }

  return $short_hostname;
}