PHP - Convert URL in text

gistfile1.php

function convertLinks($text) {
  $text = preg_replace('/(((f|ht){1}tps?:\/\/)[-a-zA-Z0-9@:;%_\+.~#?&\/\/=]+)/', '<a href="\\1" target="_blank">\\1</a>', $text);
  $text = preg_replace('/([[:space:]()[{}])(www.[-a-zA-Z0-9@:;%_\+.~#?&\/\/=]+)/', '\\1<a href="http://\\2" target="_blank">\\2</a>', $text);
  $text = preg_replace('/(([0-9a-zA-Z\.\-\_]+)@([0-9a-zA-Z\.\-\_]+)\.([0-9a-zA-Z\.\-\_]+))/', '<a href="mailto:$1">$1</a>', $text);
  return $text;
}