I'm looking to write a utility that will take an arbitary email message as input, and from this input, will determine the values of SENDER and RECIPIENT in exactly the same way as Courier determines this information.

I know that one way to do this is to read the docs and the code in order to get the exact algorithms that Courier uses to calculate these values, write the utility using these algorithms. I'm happy to do that if necessary, but before I go off and re-invent the wheel, does anyone know of a pre-existing utility which takes an email message calculates SENDER and RECIPIENT exactly the same way that Courier does it?

Thanks in advance.