PHP class for a specific search term from most search engines

PHP class SearchWord for certain search queries and search results pages in the most popular search engines.
To define the search query you want to create an instance of a class php function SearchWords SearchWord and analyze variable $ HTTP_REFERER.

The main difficulty in the design and implementation of the PHP-class is that each search engine uses its own names for variables that contain all of the information about the user's request (query text, the page in search results and other parameters). Therefore, there is only right decision - to write for each search engine has its own search queries analyzer, hence the complexity - there are more than 50 popular search engines, and how many of them exist at all - no one knows.
Another problem is the inability to obtain accurate search results page, as the number of links in search results, the user can define himself, so you can learn the approximate search results page.
The problems can be attributed more particularly some search engines, such as Google and MSN - are used at UTF-8, and Yandex - KOI8-R (the search is not on the first page of results).

Despite all the difficulties described above, I turned php class for a more or less correct analysis searches for the following search engines:

Google (http://google.ru) [all domains google]
Yandex (http://yandex.ru/) [all the basic]
Rambler (http://rambler.ru/) [search all]
Mail.Ru (http://go.mail.ru/)
Sic (http://aport.ru/)
Nigma (http://nigma.ru/)
WebAlta (http://webalta.ru/)
Yahoo (http://yahoo.com/)
MSN (http://search.msn.com/)
Poisk.Ru (http://poisk.ru)
Findme.Ru (http://findme.ru/)
Altavista
Aol
all 13 search engines.

an article about this class: http://wm-help.net/?my-articles/article/word-stat.class.htm
significantly abridged version of the class: http://wm-help.net/download/word-stat.class.php.zip