Add SPDX-License-Identifier to every source file in lib/ and cli/.
Files derived from Bobrowski's libunuc2 retain LGPL-3.0-only;
cli/src/main.c (derived from his GPL-licensed unuc2 tool) and all
new Phase 2-7 work by Valetov are GPL-3.0-or-later. No silent
LGPL-to-GPL upgrade has been applied.
CREDITS.md now lists each Bobrowski-derived file specifically rather
than crediting libunuc2 as generic 'inspiration'.
docs/license-audit.md records the full per-file provenance table,
the LGPL-3.0 -> GPL-3.0 chain rationale (LGPL sec. 4 Combined Works
is the operative clause; LGPL sec. 3 single-direction upgrade is
documented but not exercised), and confirms that:
- the 2015 LGPL-3.0 release in original/UC2_source/ is preserved
unchanged;
- the 2020-2021 LGPL/GPL releases in original/unuc2-0.6/ are preserved
unchanged;
- lib/src/super.bin is bit-identical to upstream and to de Vries's
1992 distribution data.
New library (uc2_cdc.h / uc2_cdc.c) for Phase 3 deduplication:
- Gear rolling hash: O(1) per-byte update, uniform distribution,
content-aware boundary detection via mask-based matching
- Configurable chunker: min/max/target chunk sizes (default avg 8KB),
streaming API with reset support
- FNV-1a content hash for chunk dedup addressing
- 256-entry random lookup table for Gear hash distribution
8 unit tests covering:
- Hash determinism and collision avoidance
- Complete data coverage (no bytes lost)
- Min/max chunk size enforcement
- Content-defined boundary alignment across shifted data
- Cross-file dedup detection (shared 256KB block found between
two files with different unique prefixes/suffixes)
Eremey Valetov