how to write ip filter code for apache web server

Hi Friends,
I got stuck in a problem and need your guidance to start with .

I got a module to write c++ code to filter the ip addresses that
are hitting our website and that ip addresses need to be compared from
the ip addresses in a txt file and if the ip address exist in that file
page need to be redirected.

WE are using resin as an application server and apache as a web
server.

I don't know where to start with and wat kind of stuff I need to
know to deal with.

So If you have any matrial,code or knowledge ,kindly share it with
me.
U can write to me at : neetika_mittal@hotmail.com

Thanks
Neetika