6d59bc27db
New library (uc2_dict.h / uc2_dict.c) formalizes master blocks as proper dictionaries with: - 64-bit content hash ID (FNV-1a) for cross-archive sharing - 32-bit integrity checksum with verification - Portable serialization format (24-byte header + data) - Deserialization with magic number and size validation Combined with the block store (uc2_blockstore.h), this enables distributed dedup: archives in different locations can reference shared dictionaries by content hash, with integrity verification before decompression. 6 unit tests including serialization round-trip, corruption detection, and bad-magic rejection. Also added plausible deniability (multi-archive with separate passwords) to Phase 5 roadmap.
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.