C++ arbitrarily big int code

does anyone have or no where i could find optimized c++ code/library for arbitrarily big numbers? thanks

------------------
Come, son of jor-el, kneel before zod! Snootchy Bootchies!

I have never seen one. There is one that supports 96-bit integers though and they have a very large range. Here is a link : http://www.codeproject.com/cpp/cint96.asp