正确的PHP preg_replace

So, I am using this to replace BBCode to HTML:

$text  = htmlspecialchars($text);

$advanced_bbcode = array(
  '#\[quote](
)?(.+?)\[/quote]#si',
  '#\[url](.+)\[/url]#Usi');

$advanced_html = array(
  '<blockquote class="quote">$2</blockquote>',
  '<a rel="nofollow" target="_blank" href="$1">$1</a>');

$text = preg_replace($advanced_bbcode, $advanced_html,$text);
echo nl2br($text);

public static function nl2br($var)
{
    return str_replace(array('\\
','\
','r\
','
', '
', ''), '<br />', nl2br($var));
}

This works fine if I only have 1 quote, but If I use multiple quotes like: [quote][quote][quote]first[/quote]second[/quote]end[/quote]

I expect to get:

<blockquote class="quote"><blockquote class="quote"><blockquote class="quote">first</blockquote>second</blockquote>end</blockquote>

But because it takes the first [/qoute] it will turn into:

<blockquote class="quote">[quote][quote]first</blockquote>second[/quote]end[/quote]

I've looked it up but I cant find anything that is working for me. I am new to this kind of stuff.

Thanks.

Make replace until there is BBCode in the string

do { 
   $text = preg_replace($advanced_bbcode, $advanced_html,$text,-1,$c);
} while($c);

demo