function output_gz_compressed($contents)
{
  if (stripos($_SERVER['HTTP_ACCEPT_ENCODING'], 'gzip') !== False)
  {
    $contents = gzcompress($contents, 9);
    //remove old crc
    $contents = substr($contents, 0, strlen($contents) - 4);

    header('Content-Encoding: gzip');
    header('Content-Length: ' + strlen($contents));

    //gzip header
    echo "\x1f\x8b\x08\x00\x00\x00\x00\x00";
    echo $contents;
    echo pack('V', crc32($contents));
    echo pack('V', strlen($contents));
  }
  else
    echo $contents;
}