function force_download($filename = '', $data = '', $set_mime = FALSE)
   {
if ($filename === '' OR $data === '')
      {
return;
}
elseif ($data === NULL)
      {
if ( ! @is_file($filename) OR ($filesize = @filesize($filename)) === FALSE)
         {
return;
}
$filepath = $filename;
$filename = explode(
 
'/', str_replace(DIRECTORY_SEPARATOR, '/', $filename));
$filename = end($filename);
}
else
{
$filesize = strlen($data);
}
// Set the default MIME type to send
$mime = 'application/octet-stream';
$x = explode('.', $filename);
$extension = end($x);
if ($set_mime === TRUE)
      {
if (count($x) === 1 OR $extension 
 
=== '')
         {
/* If we're going to detect the MIME type,
             * we'll need a file extension.
             */
return;
}
// Load the mime types
$mimes =& get_mimes();
// Only change the default MIME if we can find one
if (isset($mimes[$extension]))
         {
$mime = is_array($mimes[$extension
 
]) ? $mimes[$extension][0] : $mimes[$extension];
}
      }
/* It was reported that browsers on Android 2.1 (and possibly older as well)
       * need to have the filename extension upper-cased in order to be able to
       * download it.
       *
       * Reference: http://digiblog.de/2011/04/19/android-and-the-download-file-headers/
       */
if (count($x) !== 1 && isset($_SERVER['HTTP_USER_AGENT']) && preg_match('/Android\s(1|2\.[01])/', $_SERVER['HTTP_USER_AGENT']))
      {
$x[count($x) - 1] = strtoupper($extension);
$filename = implode('.', $x);
}
if ($data === NULL && ($fp = @fopen($filepath, 'rb')) === FALSE)
      {
return;
}
// Clean output buffer
if (ob_get_level() !== 0 && @ob_end_clean() === FALSE)
      {
         @ob_clean();
}
// Generate the server headers
header('Content-Type: '.$mime);
header('Content-Disposition: attachment; filename="'.$filename.'"');
header('Expires: 0');
header('Content-Transfer-Encoding: binary');
header('Content-Length: '.$filesize);
header('Cache-Control: private, no-transform, no-store, must-revalidate');
// If we have raw data - just dump it
if ($data !== NULL)
      {
exit($data);
}
// Flush 1MB chunks of data
while ( ! feof($fp) && ($data = fread($fp, 1048576)) !== FALSE)
      {
echo $data;
}
      fclose($fp);
exit;
}