How to Validate RSS or ATOM feed using simple PHP Script

Here a simple function to Validate Feed URL,

1. function getFeedStatus ($url) {
2.     $ch = curl_init();
3.     curl_setopt ($ch, CURLOPT_URL, $url);
4.     curl_setopt ($ch, CURLOPT_HEADER, 0);
5.     curl_setopt ($ch, CURLOPT_TIMEOUT, 30);
6.     curl_setopt ($ch, CURLOPT_FOLLOWLOCATION, 1);
7.     curl_setopt($ch, CURLOPT_RETURNTRANSFER,1);
8.  
9.     $string = curl_exec($ch);
10.     curl_close($ch);
11.  
12.     if (strpos($string, '<feed') > 0 && strpos($string, '</feed')) {
13.             return "ATOM";
14.     } else if (strpos($string, '<channel') > 0 && strpos($string, '</channel')) {
15.             return "RSS";
16.     } else {
17.             return "INV";
18.     }
19. }
20.