The Zlib library allows to deflate compressed files and to create gzip (.gz)
files. Zlib is free software and small.

An archive in ZIP format can contain several files compressed with this method,
while a .gz archive can containt only one file. It is a very popular format,
that is why I have written a package for reading files compressed within a Zip
archive.

WWW: http://www.winimage.com/zLibDll/minizip.html