Improved Title Case Function for PHP

John Gruber originally made available his script to Title Case text, working around the fringe-cases.

From this, a number of ports were made of the script of which particularly noteworthy David Gouch’s Javascript port that was smaller, simpler and handled more fringe cases.

I’ve ported this to PHP and put it to use on this site. My version is based on David Gouch’s Javascript port, unlike the WordPress port which is, frankly, crap.

Code below.

//original Title Case script © John Gruber <daringfireball.net>
//javascript port © David Gouch <individed.com>
//PHP port of the above by Kroc Camen <camendesign.com>

function titleCase ($title) {
	//remove HTML, storing it for later
	//       HTML elements to ignore    | tags  | entities
	$regx = '/<(code|var)[^>]*>.*?<\/\1>|<[^>]+>|&\S+;/';
	preg_match_all ($regx, $title, $html, PREG_OFFSET_CAPTURE);
	$title = preg_replace ($regx, '', $title);
	
	//find each word (including punctuation attached)
	preg_match_all ('/[\w&`\'‘’"“\.@:\/\{\(\[<>_]+-? */u', $title, $m1, PREG_OFFSET_CAPTURE);
	foreach ($m1[0] as &$m2) {
		//shorthand these- "match" and "index"
		list ($m, $i) = $m2;
		
		//correct offsets for multi-byte characters (`PREG_OFFSET_CAPTURE` returns *byte*-offset)
		//we fix this by recounting the text before the offset using multi-byte aware `strlen`
		$i = mb_strlen (substr ($title, 0, $i), 'UTF-8');
		
		//find words that should always be lowercase…
		//(never on the first word, and never if preceded by a colon)
		$m = $i>0 && mb_substr ($title, max (0, $i-2), 1, 'UTF-8') !== ':' && preg_match (
			'/^(a(nd?|s|t)?|b(ut|y)|en|for|i[fn]|o[fnr]|t(he|o)|vs?\.?|via)[ \-]/i', $m
		) ?	//…and convert them to lowercase
			mb_strtolower ($m, 'UTF-8')
			
		//else:	brackets and other wrappers
		: (	preg_match ('/[\'"_{(\[‘“]/u', mb_substr ($title, max (0, $i-1), 3, 'UTF-8'))
		?	//convert first letter within wrapper to uppercase
			mb_substr ($m, 0, 1, 'UTF-8').
			mb_strtoupper (mb_substr ($m, 1, 1, 'UTF-8'), 'UTF-8').
			mb_substr ($m, 2, mb_strlen ($m, 'UTF-8')-2, 'UTF-8')
			
		//else:	do not uppercase these cases
		: (	preg_match ('/[\])}]/', mb_substr ($title, max (0, $i-1), 3, 'UTF-8')) ||
			preg_match ('/[A-Z]+|&|\w+[._]\w+/u', mb_substr ($m, 1, mb_strlen ($m, 'UTF-8')-1, 'UTF-8'))
		?	$m
			//if all else fails, then no more fringe-cases; uppercase the word
		:	mb_strtoupper (mb_substr ($m, 0, 1, 'UTF-8'), 'UTF-8').
			mb_substr ($m, 1, mb_strlen ($m, 'UTF-8'), 'UTF-8')
		));
		
		//resplice the title with the change (`substr_replace` is not multi-byte aware)
		$title = mb_substr ($title, 0, $i, 'UTF-8').$m.
			 mb_substr ($title, $i+mb_strlen ($m, 'UTF-8'), mb_strlen ($title, 'UTF-8'), 'UTF-8')
		;
	}
	
	//restore the HTML
	foreach ($html[0] as &$tag) $title = substr_replace ($title, $tag[0], $tag[1], 0);
	return $title;
}

Anything broken, please let me know.
Kind regards,