使用preg_replace添加函数

Question

How can I add in the getTitleText() function so that the anchor text displays the page title using the URL that the regular expression has found?

function getTitleText($Url){
 $str = file_get_contents($Url);
   if(strlen($str)>0){
     preg_match("/\<title\>(.*)\<\/title\>/",$str,$title);
    return $title[1];
  }
}

$comment = preg_replace('/((([A-Za-z]{3,9}:(?:\/\/)?)(?:[-;:&=\+\$,\w]+@)?[A-Za-z0-9.-]+|(?:www.|[-;:&=\+\$,\w]+@)[A-Za-z0-9.-]+)((?:\/[\+~%\/.\w-_]*)?\??(?:[-\+=&;%@.\w_]*)#?(?:[\w]*))?)/', '<a target="_blank" rel="nofollow" href="$0">$0</a>',$comment);