Fast Base64 (encode / decode)

After spending hours on the internet and hours in the train, reading documents about base64 encoding, looking at c++ examples and trying to convert delphi examples into vb code using bitshifting and pointers, i came acros a piece of code which was the fastest on PSC, i downloaded it, cleaned up the code, improved the methods for loading file (increase from 9 mb/sec to 40 mb/sec) and for spanning / unspanning files. Fixed bug in spanning too. THIS IS NOT (ENTIRELY) MY CODE... I will respond as much as i can to your questions...