gistfile1.php

<?php
/**
 * Converts text anchors into links.
 *
 * @param   string   text to auto link
 * @return  string
 */
public static function auto_link_urls($text)
{

	$regex = '~\\b'
			.'((?:ht|f)tps?://)?' // protocol
			.'(?:[-a-zA-Z0-9]{1,63}\.)+' // host name
			.'(?:[0-9]{1,3}|aero|asia|biz|cat|com|coop|edu|gov|info|int|jobs|mil|mobi|museum|name|net|org|pro|tel|travel|ac|ad|ae|af|ag|ai|al|am|an|ao|aq|ar|as|at|au|aw|ax|az|ba|bb|bd|be|bf|bg|bh|bi|bj|bm|bn|bo|br|bs|bt|bv|bw|by|bz|ca|cc|cd|cf|cg|ch|ci|ck|cl|cm|cn|co|cr|cu|cv|cx|cy|cz|de|dj|dk|dm|do|dz|ec|ee|eg|er|es|et|eu|fi|fj|fk|fm|fo|fr|ga|gb|gd|ge|gf|gg|gh|gi|gl|gm|gn|gp|gq|gr|gs|gt|gu|gw|gy|hk|hm|hn|hr|ht|hu|id|ie|il|im|in|io|iq|ir|is|it|je|jm|jo|jp|ke|kg|kh|ki|km|kn|kp|kr|kw|ky|kz|la|lb|lc|li|lk|lr|ls|lt|lu|lv|ly|ma|mc|md|me|mg|mh|mk|ml|mm|mn|mo|mp|mq|mr|ms|mt|mu|mv|mw|mx|my|mz|na|nc|ne|nf|ng|ni|nl|no|np|nr|nu|nz|om|pa|pe|pf|pg|ph|pk|pl|pm|pn|pr|ps|pt|pw|py|qa|re|ro|rs|ru|rw|sa|sb|sc|sd|se|sg|sh|si|sj|sk|sl|sm|sn|so|sr|st|su|sv|sy|sz|tc|td|tf|tg|th|tj|tk|tl|tm|tn|to|tp|tr|tt|tv|tw|tz|ua|ug|uk|us|uy|uz|va|vc|ve|vg|vi|vn|vu|wf|ws|ye|yt|yu|za|zm|zw)' // tlds
			.'(?:/[!$-/0-9:;=@_\':;!a-zA-Z\x7f-\xff]*?)?' // path
			.'(?:\?[!$-/0-9:;=@_\':;!a-zA-Z\x7f-\xff]+?)?' // query
			.'(?:#[!$-/0-9:;=@_\':;!a-zA-Z\x7f-\xff]+?)?' // fragment
			.'(?=[?.!,;:"]?(?:\s|$))~'; // punctuation and url end

	$result = "";
	$position = 0;

	while (preg_match($regex, $text, $match, PREG_OFFSET_CAPTURE, $position))
	{
		list($url, $url_pos) = $match[0];

		// Add the text before the url
		$result  .= substr($text, $position, $url_pos - $position);

		// Default to http://
		$full_url = empty($match[1][0]) ? 'http://'.$url : $url;

		// Add the hyperlink.
		$result .= html::anchor($full_url, $url);

		// New position to start parsing
		$position = $url_pos + strlen($url);
	}

	return $result.substr($text, $position);
}