I want to change the length of the shortened ID in PHPurl

I've installed PHPurl a URL shortener (from http://blondish.net/resources/scripts/phpurl/) to my website and customised it to the style of my site.

Everything works okay, except it generates the URL id by adding one number each time. For example: .http://)jpine.co.uk/1 then to .http://jpine.co.uk/2

I want it to look a bit more like bit.ly and have .http://jpine.co.uk/42t8hnf - a random generated number. I'm not sure how to do this but I'm relatively sure that it calculates it in the create.php. Here it is below:

<?
include("config.php");
if (strstr($_SERVER['HTTP_REFERER'], $root));
else { header ("Location: $rooturl"); }

$ip = $_SERVER['REMOTE_ADDR'];
$url = mysql_real_escape_string($_POST['url']);

if(preg_match('|^http(s)?://[a-z0-9-]+(\.[a-z0-9-]+)*(:[0-9]+)?(/.*)?$|i', $url)) {
    if (empty($_POST['tag'])) {
        $query = mysql_query("INSERT INTO $table (ip,url) VALUES ('$ip','$url')") or die('MySQL error: '.mysql_error());
        $qs = mysql_insert_id();
    } else {
        if (ereg('^[a-zA-Z0-9]+[a-zA-Z0-9]+$', $_POST['tag'])) {
            $tag = mysql_real_escape_string($_POST['tag']);
            $query = mysql_query("select * from $table where `tag` = '$tag';") or die('MySQL error: '.mysql_error());
            if (mysql_num_rows($query) != 0)
                die("This tag has already been used! Please press back button on your browser and choose anothe开发者_如何学Gor tag!");
            else {
                $query = mysql_query("insert $table (ip,url,tag) VALUES ('$ip','$url','$tag')") or die('MySQL error: '.mysql_error());
                $qs = $tag;
            }
        } else
            die('Your tag contains invalid characters! Only alphabets and numbers allowed! Please press back button on your browser and choose another tag!');
    }
    $link = $destination . $qs;
    require 'create_template.php';
} else
    echo 'URL is invalid';

?>

Not that easy. You need to change whole lot of things and database.

You could try it the way it's described here: short id's like YouTube or Tinyurl.