unique hit counter p2

<?php
    $filename = 'counter.txt';
    $ip_filename = 'ip.txt';

    function inc_count() {
        $ip = $_SERVER['REMOTE_ADDR'];
        global $filename, $ip_filename;

        if(!in_array($ip, file($ip_filename, FILE_IGNORE_NEW_LINES))) {
            $current_value = (file_exists($filename)) ? file_get_contents($filename) : 0 ;
            file_put_contents($ip_filename, $ip."\n", FILE_APPEND);
            file_put_contents($filename, ++$current_value);
        }
    }

    inc_count();

?>