PHP referrer code

I need some help with PHP code. I have popup on my site, but want to exclude it if visitor comes from certain site. How can I do that ?

 

if (!empty($_SERVER['HTTP_REFERER']) AND $parts = @parse_url($_SERVER['HTTP_REFERER']))
{
    $blocked_hosts = array('some.com', 'site.com', 'blah.com');   
    $host = preg_replace('~^www\.~', null, strtolower($parts['host']));

    if (!in_array($host, $blocked_hosts))
    {
        // Request comes from one of the sites that's NOT in the array above.
    }
    else
    {
        // You know the deal
    }
}

PHP:

 

Muchas Gracias