External PHP Library

I require a working C library that i can refrence from PHP. The library will perform a series of functions to modify a text block (involving a variation [if nesseceary] of the ord and chr functions). The library must be in plain source and I will require all source files so i can compile it into an .so file. The system will: take a block of text as specified by a function eg: dec("ionfesou08480cnin e904", 1234); and base64 decode it, then for modify the string using the specified number. the reason i need this project to be in an .so format is for portability, and ease of use in php. ## Deliverables 1) Complete and fully-functional working program(s) in executable form as well as complete source code of all work done. 2) Installation package that will install the software (in ready-to-run condition) on the platform(s) specified in this bid request. (makefile for linux and freebsd) 3) Exclusive and complete copyrights to all work purchased. (No GPL, GNU, 3rd party components, etc. unless all copyright ramifications are explained AND AGREED TO by the buyer on the site per the coder's Seller Legal Agreement). ## Platform needs to run on: Linux FreeBSD and if possible, Windows. (linux and freebsd are more important)