PHP Decode

<?php 
 
 
$user_agent     =   $_SERVER['HTTP_USER_AGENT']; 
 
function getOS() {  
 
    global $user_agent; 
 
    $os_platform    =   "Unknown OS Platform"; 
 
    $os_array       =   array( 
                            '/windows nt 10/i'     =>  'Windows 10', 
                            '/windows nt 6.3/i'     =>  'Windows 8.1', 
                            '/windows nt 6.2/i'     =>  'Windows 8', 
                            '/windows nt 6.1/i'     =>  'Windows 7', 
                            '/windows nt 6.0/i'     =>  'Windows Vista', 
                            '/windows nt 5.2/i'     =>  'Windows Server 2003/XP x64', 
                            '/windows nt 5.1/i'     =>  'Windows XP', 
                            '/windows xp/i'         =>  'Windows XP', 
                            '/windows nt 5.0/i'     =>  'Windows 2000', 
                            '/windows me/i'         =>  'Windows ME', 
                            '/win98/i'              =>  'Windows 98', 
                            '/win95/i'              =>  'Windows 95', 
                            '/win16/i'              =>  'Windows 3.11', 
                            '/macintosh|mac os x/i' =>  'Mac OS X', 
                            '/mac_powerpc/i'        =>  'Mac OS 9', 
                            '/linux/i'              =>  'Linux', 
                            '/ubuntu/i'             =>  'Ubuntu', 
                            '/iphone/i'             =>  'iPhone', 
                            '/ipod/i'               =>  'iPod', 
                            '/ipad/i'               =>  'iPad', 
                            '/android/i'            =>  'Android', 
                            '/blackberry/i'         =>  'BlackBerry', 
                            '/webos/i'              =>  'Mobile' 
                        ); 
 
    foreach ($os_array as $regex => $value) {  
 
        if (preg_match($regex, $user_agent)) { 
            $os_platform    =   $value; 
        } 
 
    }    
 
    return $os_platform; 
 
} 
 
 
?>