How to parse CVS output?

[Chris]

Hi all,

I have to write some PHP code to invoke CVS. Calling cvs is trivial,
but parsing the output isn't. For example, when I call cvs log to see
if a file exists, I want to be able to say 'yes' or 'no', instead of
printing the raw output. You get the idea.

PHP has Perlesque regex functions, so I can do all this by hand, but
I'd feel better if I had formal specs or something on the output
generated by cvs. (Other than the source code, I mean.)

Any ideas?
Thanks,
Chris