obtaining stream length from mad decoder

Hi Guys,

 

I have written a Managed C++ wrapper for the libMad decoder, and I would
like to know.... How can I get EITHER, the _decoded_ length in bytes, or the
duration in seconds of the whole file, without decoding the whole file?

I need to just evaluate a set of mp3 files, and obtain their lengths
(preferably in bytes, then I can calculate the length in seconds by the
bytes-per-second)

Thanks!

 

 - Adam