Move FSE normalized-count parsing, Huffman statistics decoding, FSE table
construction, and FSE stream decompression into Rust. The C source files now
only retain the headers needed by the existing build configuration.
The implementation keeps the public C ABI and verifies C-generated balanced,
skewed, and Huffman-statistics streams. Compression and the higher-level frame
decoder remain C for now.
Test Plan:
- cargo fmt --check
- cargo test --all-targets
- cargo clippy --all-targets -- -D warnings
- cargo build --release
- compile both C shims with -Werror and -Wredundant-decls
Refs: rust/README.md
The common C shims include headers that already declare every Rust-exported
symbol. Remove duplicate declarations so strict C builds do not report
redundant declarations or macro-expanded aliases.
The shims remain intentionally declaration-only; Rust still owns the exported
implementation.
Test Plan:
- compile debug.c with -Wall -Wextra -Werror
- compile error_private.c with -Wall -Wextra -Werror
- compile zstd_common.c with -Wall -Wextra -Werror
Refs: rust/README.md
Introduce the Rust static library and move the shared byte, bitstream, CPU,
error, xxHash, debug, and public-common implementations into it. Thin C shims
preserve the existing header-driven C build while original tests link the Rust
archive.
This establishes the ABI-safe foundation for later codec and CLI ports;
entropy coding, runtime support, codecs, dictionaries, and the CLI remain C.
The top-down migration map documents that boundary and its validation path.
Test Plan:
- cargo fmt --check
- cargo test --all-targets
- cargo clippy --all-targets -- -D warnings
- cargo build --release
Refs: rust/README.md
this ABI is no longer supported by Ubuntu,
and there is a wider consensus that this ABI is on the way out,
with more and more distributions dropping it,
and lingering questions about support of x32 in the kernel.
the purpose of --ultra is to make the user explicitly opt-in
to generate very large window size (> 8 MB).
The agreement to generate very large window size is already implicit
when selecting --long or --patch-from.
Consequently, `--ultra ` is automatically enabled when `--long` or `--patch-from` is set.
ddidderr
