PHP modules (pecl) and PHP codes (pear)

Hi, I'll have to develop a function like "parse_url", but "parse_referrer" which provides informations about the URL (the referrer): provider, keywords, type of search (search, cache, translation, ...), real page url... I don't really know how I'll do that: using a .ini file like "get_browser" ? I think it will be too complicated and difficult to build.. but maybe it is a good idea ? Or create it in C as an extension... I want to know if compiled extensions in C are really faster than an PHP function ? Thanks ! Samuel.