snacc question

Hello,
Hello,

I am new to snacc, and have a very basic question.

I have an internal data structure (an SNMP trap), and I would like to encode
it into BER format.

The snacc home page says that:

"Given an ASN.1 source file(s) snacc can produce:

* C routines for BER encoding, decoding, printing and freeing.
* C++ routines for BER encoding, decoding, and printing.
* A type table that can be used with generic C routines for BER encoding,
decoding, printing and freeing."

My question is, what do they mean by "Given an ASN.1 source file"? I am
starting with a data structure in non-ASN.1 format, and I want to decode
into into ASN.1 (BER) format. Can the snacc tool accomplish this task? What
is the ASN.1 source file and how does it fit in?

Thanks,

Chris