Does anybody know of a good virtual file system library?

I'm looking for a C/C++ api that would allow me file-system-like access to files that are stored in a single zip file (or archive of some kind).
I need a cross-platform API that works on windows as well as linux.
I've found a few on the web, but many are either java-based (which won't work for me) or are not yet production ready.
I'm looking for a relatively mature open-source library that I could use in production code.

All suggestions welcome - thanks in advance!