Wiretap library

I have a need to work with a large amount of compressed (.gz) packet  
header data obtained from ethernet sources with tcpdump.  In  
compressed form, there are on the order of 10,000 files totaling  
about 160GB.

I would like to be able to open the files, and read the records  
without decompressing each file first.  The current version of the  
program uses libpcap and I decompress the input into a pipe.  I can  
only process one file per run and a large portion of my time is taken  
up with saving and restoring state between runs.

Has anyone had experience using wiretab as a library to support this  
kind of activity?  Is there any documentation that would help  
identify the appropriate interface routines?  A search of the  
ethereal site shows discussion of this in the early days of the  
project, but nothing recently.

John McHugh