PHP에서 스택 오버플로의 자동 링크 동작을 모방하는 방법은 무엇입니까?

<code class="php">function auto_link_text($text)
{
   $pattern  = '(?i)\b((?:[a-z][\w-]+:(?:/{1,3}|[a-z0-9%])|www\d{0,3}[.]|[a-z0-9.\-]+[.][a-z]{2,4}/)(?:[^\s()<>]+|\(([^\s()<>]+|(\([^\s()<>]+\)))*\))+(?:\(([^\s()<>]+|(\([^\s()<>]+\)))*\)|[^\s`!()\[\]{};:\'"",<>?«»“”‘’]))';
...
}</code>

<code class="php">...
$text       = parse_url($url, PHP_URL_HOST) . parse_url($url, PHP_URL_PATH);
$text       = preg_replace("/^www./", "", $text);
$last       = -(strlen(strrchr($text, "/"))) + 1;
...</code>

<code class="php">$text = "...";
$linked_text = auto_link_text($text);</code>

Input: This is my text. Check This out http://www.stackoverflow.com/questions/1925455/how-to-mimic-stackoverflow-auto-link-behavior

Output: This is my text. Check This out <a href="http://www.stackoverflow.com/questions/1925455/how-to-mimic-stackoverflow-auto-link-behavior">stackoverflow.com/questions/1925455/...</a>