UC2 v3.0.0 — UltraCompressor II

A cross-platform revival of UltraCompressor II, the DOS-era archiver by Nico de Vries (1992--1996). UC2 was notable for its advanced deduplication ("master blocks"), file versioning, and competitive compression ratios on the hardware of its day.

This project brings UC2 back as a modern, portable C99 tool. Phase 1 (current) provides decompression and archive listing, built on Jan Bobrowski's clean-room portable decompressor (unuc2/libunuc2). Phase 2 will add compression using the original algorithms.

Building

Requires CMake >= 3.16 and a C99 compiler (GCC, Clang, or MSVC).

cmake -B build
cmake --build build

The binary is at build/cli/uc2.

Usage

uc2 archive.uc2                       # Extract all files
uc2 -l archive.uc2                    # List contents
uc2 -t archive.uc2                    # Test archive integrity
uc2 -d /tmp/out archive.uc2           # Extract to directory
uc2 -l archive.uc2 '*.txt'            # List matching files
uc2 -p archive.uc2 readme.txt         # Extract to stdout

Options

Flag	Description
-l	List archive contents
-t	Test archive integrity
-a	Include all file versions (not just latest)
-d path	Extract to specified directory
-f	Overwrite existing files
-p	Extract to stdout
-D	Skip directory metadata; -DD also skips file metadata
-T	Tab-separated output (for scripting)

Project Structure

UC2/
  lib/            libuc2 decompression library
  cli/            uc2 command-line tool
  original/       preserved original sources (reference only)
  cmake/          build system modules
  tests/          test archives and test programs

History

• v1.0--v2.3 (1992--1996) Original DOS releases by Nico de Vries
• 2015 Source code released under LGPL-3.0 by Danny Bezemer
• 2020--2021 Jan Bobrowski writes unuc2/libunuc2 (portable decompressor)
• 2026 UC2 v3.0.0: cross-platform revival

License

GPL-3.0. See LICENSE and CREDITS.md for full attribution.