get file size of remote url

function getSizeFile($url)
  {
    if (substr($url,0,4)=='http') {
        $x = array_change_key_case(get_headers($url, 1),CASE_LOWER);
        if ( strcasecmp($x[0], 'HTTP/1.1 200 OK') != 0 ) { $x = $x['content-length'][1]; }
        else { $x = $x['content-length']; }
    }
    else { $x = @filesize($url); }
    
    return $x;
  } 

from:　http://php.net/manual/en/function.filesize.php