[Exim] local_scan spam filter

I have written a reasonable spam filter in 'c' which blocks
on various header fields and message body content. (re-invent the wheel?)

I like the idea of blocking this junk mail instantly, that is within
local_scan so that the message gets refused while the SMTP session is
active.

Anyways, I find that lots of message body content is obfuscated by hiding
inside base64 encoding.

Can someone offer a reasonable method to convert the base64 message content
to ascii within a 'c' routine without forking and creating excessive
overhead?
--
Jim Pazarena    mailto:paz@qcislands.net
                http://www.qcislands.net/paz