The Zip-Ada library is written entirely in Ada, allowing compression
operations without any OS-dependent external calls on streams and files.

In addition to the library and command-line demos, it has these tools:
 * zipada   - create compressed Zip archive
 * comp_zip - utility to compare contents of two Zip archives
 * find_zip - utility to search for text stream of Zip archive
 * rezip    - tool for recompressing Zip archives towards optimal compression
 * debzip2  - tool to decompress BZip2 compressed files (.bz2)

WWW: http://unzip-ada.sourceforge.net/