Come estrarre sistema operativo e browser usati a partire da User Agent?

[portapipe]

Browser:

$useragent = $_SERVER['HTTP_USER_AGENT'];
if (preg_match('|MSIE ([0-9].[0-9]{1,2})|',$useragent,$matched)) {
   $browser_version=$matched[1];
   $browser = 'IE';
} elseif (preg_match( '|Opera ([0-9].[0-9]{1,2})|',$useragent,$matched)) {
   $browser_version=$matched[1];
   $browser = 'Opera';
} elseif(preg_match('|Firefox/([0-9\.]+)|',$useragent,$matched)) {
   $browser_version=$matched[1];
   $browser = 'Firefox';
} elseif(preg_match('|Safari/([0-9\.]+)|',$useragent,$matched)) {
   $browser_version=$matched[1];
   $browser = 'Safari';
} else {
   // browser not recognized!
   $browser_version = 0;
   $browser= 'Altro';
} 

Sistema operativo:

$useragent = $_SERVER['HTTP_USER_AGENT'];
if (strstr($useragent,'Win')) {
   $os='Windows';
} else if (strstr($useragent,'Mac')) {
   $os='Mac';
} else if (strstr($useragent,'Linux')) {
   $os='Linux';
} else if (strstr($useragent,'Unix')) {
   $os='Unix';
} else {
    $os='Altro';
}
        
return $os;