What does wikipedia use for text and revision diffs

I'm trying to take 2 versions of text (10 pages long) and compare the 2 to produce the difference. I know Wikipedia has a similar feature to compare revisions. Does 开发者_C百科anyone know what they use? I'm hoping they're using a php-driven solution.

There is an implimentation of diff in php. I haven't used it but it's a start. There is also something called PHP inline diff that you can check out