In this recent thread a suggestion was proffered by japhy to try his LWP::Filehandle module.

It's not that long, and it does import another module (URI::Escape) but the functions he uses from that module can be coded yourself by reading its docs -- it says pretty explicitly what regexes to use.

Essentially you'd be re-writing his module for your own local use, but it has all the pieces you'd need -- of course you could just cut-and-paste the necesary code and call the subs directly -- I'm sure you can figure it out from here.