Move the implementation of programs/benchfn.c into rust/src/benchfn.rs and
wire benchmark mode (-b/-e/-i) into the Rust CLI frontend, which previously
rejected those options as not yet implemented. `zstd -b1 -i0 FILE` and range
runs like `zstd -b5e6 -i0 FILE` work again, including the synthetic-sample
benchmark when no file is given.
benchfn.rs is a faithful port of the run/timing state machine:
BMK_benchFunction keeps the exact loop accounting (first-loop blockResults
and errorFn checks, dstSize summed on the first loop only, 0xE5 warm-up of
result buffers, nbLoops minimum of 1) and BMK_benchTimedFn keeps the same
convergence behavior (x10 workload growth for short runs, budget-based
nbLoops estimation, runs below half the run budget re-tried rather than
reported, best qualifying run returned). Arithmetic that C leaves to
unsigned wrap-around uses wrapping operations so debug builds cannot panic
where release C would wrap.
ABI notes: BMK_runTime_t and BMK_runOutcome_t are returned by value across
the C boundary and BMK_benchParams_t is passed by value, so all three are
repr(C) mirrors of benchfn.h; their field offsets are pinned by const
asserts in Rust and matching C static asserts in the benchfn.c shim, which
is now declaration-only. BMK_timedFnState_t stays opaque, fits the 64-byte
BMK_timedFnState_shell (compile-time checked), and is malloc/free-managed
so creation and destruction remain interchangeable with C callers.
The CLI parses -b (bench mode), -e (range end, digits attach directly,
defaulting to 0 like readU32FromChar) and -i (duration in seconds), then
dispatches through a new ZSTD_rust_cli_bench bridge in the zstdcli.c shim.
The bridge exists because benchmark availability is a C preprocessor
property (ZSTD_NOBENCH): orchestration and reporting stay in C benchzstd.c,
stripped variants (zstd-small, zstd-compress, zstd-decompress) compile the
stub branch and report "benchmark mode is not available in this build", and
the Rust side never references benchmark symbols directly. Level clamping
against ZSTD_maxCLevel() happens in the bridge, where the symbol is
guaranteed to exist whenever benchmarking is compiled in. -T selects the
worker count, defaulting to single-threaded like the C bench path; -S
(separate files) and --priority=rt remain unimplemented.
Makefile updates only extend the Rust source prerequisite lists with
benchfn.rs; the helpers-archive plumbing from the timefn commit already
links fullbench(-lib/-dll/32) and paramgrill, the benchfn consumers among
the C tests. Original C test sources are untouched.
Known pre-existing issues, unchanged by this commit: tests/fullbench-lib
fails to link at the base commit too (libzstd.a precedes fullbench.c in its
link line), and the cli-tests basic/help.sh, compression/levels.sh,
compression/golden.sh, and decompression/pass-through.sh scripts fail
identically with a base-commit binary because the Rust CLI frontend is
still a partial reimplementation.
Test Plan:
- cd rust && cargo fmt --check && cargo clippy --all-targets -- -D warnings
&& cargo test --all-targets && cargo build --release
- cd rust/cli && cargo fmt --check && cargo clippy --all-targets -- -D
warnings && cargo test --all-targets; repeat tests with
--no-default-features plus features compression / decompression / (none)
- make -C programs zstd; ./programs/zstd -b1 -i0 lib/common/xxhash.c;
./programs/zstd -b5e6 -i0 programs/fileio.c; ./programs/zstd -b1 -i0
(synthetic); echo roundtrip via zstd | zstd -d
- make -C programs zstd-small zstd-compress zstd-decompress zstd-nolegacy
zstd-dictBuilder; zstd-small -b reports benchmark unavailable; compress/
decompress roundtrip across the split binaries
- make -C tests fullbench fuzzer zstreamtest paramgrill decodecorpus
poolTests fullbench32 fuzzer32; ./tests/fullbench -i0 (exercises Rust
BMK_benchTimedFn from C); ./tests/fullbench32 -i0; ./tests/fuzzer -i1
--no-big-tests; ./tests/poolTests; make -C tests test-rust-lib-smoke
- cli-tests subset: basic/version.sh, compression/basic.sh,
compression/multiple-files.sh pass; failing scripts match the base commit
Refs: rust/README.md
Move the implementation of programs/timefn.c into rust/src/timefn.rs. The
file provides the monotonic nanosecond clock (UTIL_getTime, span helpers,
UTIL_waitForNextTick, UTIL_support_MT_measurements) used by the CLI and by
several C test tools. timefn.c remains as a declaration-only shim so the
original source lists and header configuration keep working, and it pins the
ABI with static asserts: UTIL_time_t is returned by value and must stay a
plain 64-bit counter, which the Rust #[repr(C)] mirror also asserts.
Platform selection mirrors the C preprocessor structure: Windows uses
QueryPerformanceCounter, Apple targets use mach_absolute_time, and other
POSIX systems use libc clock_gettime(CLOCK_MONOTONIC). Only the unix path is
exercised by this environment; the Windows and Apple paths are written from
the C source and compile-checked logically but are untested here. The C90
clock() fallback is unreachable on Rust-supported targets, so multi-threaded
measurement support is always reported.
The symbols live in the program-only zstd-cli-rs package, keeping them out
of library builds. Linking that archive into C test binaries surfaced a
structural problem: rustc's local ThinLTO promotes internal symbols across
codegen units, so extracting the timefn object could drag in the zstd_cli
parser object, whose FIO_* externs test binaries cannot satisfy. The parser
is therefore gated behind a new additive `cli` cargo feature (default on).
Program archives build with cli,compression,decompression as before, while
tests/Makefile links a helpers-only archive (rust/target/cli-helpers) built
with --no-default-features, which contains no fileio references at all.
tests/Makefile gains build rules for the helpers archive and adds it as a
prerequisite of every binary that compiles the timefn shim: fullbench(32),
fullbench-lib, fullbench-dll, fuzzer(32), zstreamtest(32/asan/tsan/ubsan),
paramgrill, decodecorpus, and poolTests. Prerequisite order places the
archive after all C objects in `$^` link lines; the known-broken -dll
recipes filter to %.c, so they name the archive explicitly. Original C test
sources are untouched; only link inputs changed.
zstd-cli-rs now depends on libc (already used by the core crate) for
clock_gettime and the Mach timebase bindings.
Test Plan:
- cd rust && cargo fmt --check && cargo clippy --all-targets -- -D warnings
&& cargo test --all-targets && cargo build --release
- cd rust/cli && cargo fmt --check && cargo clippy --all-targets -- -D
warnings && cargo test --all-targets; repeat tests with
--no-default-features plus features compression / decompression / (none)
- make -C programs zstd; roundtrip echo hello | zstd | zstd -d
- make -C tests fullbench fuzzer zstreamtest paramgrill decodecorpus
poolTests; ./tests/fullbench -i0; ./tests/fuzzer -i1 --no-big-tests;
./tests/poolTests; make -C tests test-rust-lib-smoke
- verified with nm that the helpers archive member defining UTIL_getTime has
no FIO_*/ZSTD_* undefined references
Refs: rust/README.md
Continue the incremental zstd_compress.c migration with its frame
serialization leaves: ZSTD_writeFrameHeader(), the public
ZSTD_writeSkippableFrame() ABI, and ZSTD_writeLastEmptyBlock() now live
in rust/src/zstd_compress_frame.rs.
ZSTD_writeFrameHeader() reads five fields out of ZSTD_CCtx_params, whose
layout is private to zstd_compress.c and sensitive to build
configuration. Rather than mirror that structure in Rust, the C
function keeps its original static signature and forwards the scalar
fields to ZSTD_rust_writeFrameHeader(), so no parameter-structure layout
crosses the language boundary. The other two functions take only
pointer/size arguments and are exported directly, replacing their C
bodies outright.
Behavior differences are limited to hardening in release builds: the
Rust leaf clamps a window-size shift that C would leave undefined for a
malformed windowLog, and ZSTD_writeSkippableFrame() rejects a srcSize +
header overflow instead of comparing against a wrapped sum. Both paths
are unreachable through validated callers, so compressed output is
byte-identical.
Remaining zstd_compress.c work: parameter selection and validation,
context lifecycle, block dispatch, dictionary loading, and the streaming
state machine.
Test plan:
- cd rust && cargo fmt --check && cargo clippy --all-targets -- -D
warnings && cargo test --all-targets (118 tests, includes new frame
header/skippable/last-block reference vectors)
- make -C tests fuzzer && ./tests/fuzzer -i1 --no-big-tests
- make -C tests test-rust-lib-smoke
Move long-distance matching and high-level decompression from C shims into
Rust. The decoder now owns context, dictionary, parameter, one-shot, and
buffered streaming state while C retains allocation/configuration, legacy,
and trace leaves.
Move CLI parsing, safety policy, and dispatch into a separate Rust static
archive. Keeping it separate prevents library builds from retaining FIO
symbols, while C continues to own file opening, replacement, and I/O.
Program targets now select matching compression/decompression archives.
The remaining C boundary is intentional: high-level compression, optimal
parsing, dictionary building, legacy callbacks, and CLI file I/O still need
migration.
Test Plan:
- cargo test --all-targets (native and i686)
- cargo test --all-targets in rust/cli (native and i686)
- CLI crate compression-only and decompression-only feature tests
- native and i686 fuzzer/zstreamtest runs, plus legacy and dictionary tests
- ZSTD_C_PREDICT and ZSTD_HEAPMODE=0 fuzzer coverage
- library, dynamic-link, and program-target build/round-trip matrix
Refs: rust/README.md
Move the binary-tree table maintenance shared by optimal compression strategies
into Rust. A small C projection preserves the private match-state boundary;
the dynamic-programming parser and match selection remain C-owned for now.
The Rust implementation covers prefix and external-dictionary tree updates and
preserves the optional C predictor path. The component map now distinguishes
this migrated tree layer from the remaining optimal parser.
Test Plan:
- cargo test --all-targets
- cargo test --target i686-unknown-linux-gnu --all-targets
- cargo clippy && cargo clippy --benches && cargo clippy --tests
- cargo +nightly fmt
- make -B -C tests -j2 fuzzer zstreamtest invalidDictionaries
- ./tests/fuzzer -s5346 -i1 --no-big-tests
- ./tests/zstreamtest -i3000 -s334462
- ./tests/invalidDictionaries
- make -B -C tests fuzzer32 MOREFLAGS=-DZSTD_C_PREDICT
- ./tests/fuzzer32 -s5346 -i1 --no-big-tests
- byte-compare C and Rust-control CLI output at levels 13, 16, 19, and 22
for random, patterned, zero, and dictionary inputs with and without
ZSTD_C_PREDICT
Refs: rust/README.md
Move literal decoding, sequence-table construction, FSE sequence decoding, and
sequence execution into Rust. The C shim retains ownership of the configured
decoder context and passes only the leaf state needed by the block codec.
Correct the two high offset-code bases while porting the tables. Their prior
values made valid large-window streams decode as corrupted data; the new unit
test fixes the exact values and a native zstream regression exercises them.
High-level frame and streaming context control remains C for now.
Test Plan:
- cargo test --all-targets
- cargo test --target i686-unknown-linux-gnu --all-targets
- cargo clippy && cargo clippy --benches && cargo clippy --tests
- cargo +nightly fmt
- make -B -C tests -j2 fuzzer zstreamtest invalidDictionaries poolTests
- ./tests/fuzzer -s5346 -i1 --no-big-tests
- ./tests/zstreamtest -i3000 -s334462
- ./tests/invalidDictionaries
- timeout 20s stdbuf -oL ./tests/poolTests
Refs: rust/README.md
Move the two-table fast match finder into Rust while retaining a small C
projection of the private match-state. The Rust implementation handles normal,
attached-dictionary, and external-dictionary matching without exposing the
full C context ABI. The C entry points and build-time exclusion guards remain
unchanged for configured consumers.
Document the migrated matcher in the Rust component map and narrow the
remaining-C boundary accordingly.
Test Plan:
- cargo test --all-targets
- cargo test --target i686-unknown-linux-gnu --all-targets
- cargo clippy && cargo clippy --benches && cargo clippy --tests
- cargo +nightly fmt
- make -B -C tests -j2 fuzzer zstreamtest invalidDictionaries poolTests
- ./tests/fuzzer -s5346 -i1 --no-big-tests
- ./tests/zstreamtest -i3000 -s334462
- ./tests/invalidDictionaries
- timeout 20s stdbuf -oL ./tests/poolTests
Refs: rust/README.md
Move the context-free public ZSTD_compressBound ABI into Rust while leaving
the stateful compressor context in C. The Rust implementation preserves the
size-width-specific input limit, macro arithmetic, and srcSize_wrong error
contract used by C callers.
Test Plan:
- cargo clippy
- cargo clippy --benches
- cargo clippy --tests
- cargo +nightly fmt
- cargo test zstd_compress_api::tests -- --nocapture
- cargo test --target i686-unknown-linux-gnu zstd_compress_api::tests
- make -B -C lib -j2 libzstd.a
- fuzzer -s5346 -i1 --no-big-tests
Refs: public ZSTD_COMPRESSBOUND macro in lib/zstd.h
Move fast hash-table filling and no-dictionary, external-dictionary, and
attached-CDict match loops into Rust. The C shim keeps `ZSTD_MatchState_t`
opaque, extracts only its needed fields, and asserts the mirrored SeqStore
leaf layout so existing compression dispatch remains ABI-compatible.
Test Plan:
- cargo clippy
- cargo clippy --benches
- cargo clippy --tests
- cargo +nightly fmt
- cargo test zstd_fast::tests -- --nocapture
- cargo test --target i686-unknown-linux-gnu zstd_fast::tests -- --nocapture
- byte-identical C-control frames for dictionary and streaming variants
- fuzzer -s2066 -i5 --no-big-tests
- invalidDictionaries and zstreamtest -i1
Refs: Rust superblock port fde1d70c
Move subblock partitioning, literal and sequence section emission, entropy
fallback, and repcode repair into Rust. Keep a narrow C wrapper to read the
opaque compression context and invoke the existing C entropy-stat builder;
the Rust side owns only verified C-shaped leaf layouts.
Test Plan:
- cargo clippy
- cargo clippy --benches
- cargo clippy --tests
- cargo +nightly fmt
- cargo test zstd_compress_superblock::tests -- --nocapture
- cargo test --target i686-unknown-linux-gnu zstd_compress_superblock::tests
- byte-exact C control across 16 target-size and input-shape cases
- fuzzer, zstreamtest, invalidDictionaries, and bounded native test matrix
Refs: Rust sequence entropy port 887af204
Move FSE table-costing, table construction, encoding selection, and sequence
bitstream emission into Rust while retaining the existing C internal-header
boundary. The shim preserves all five C ABI entry points, so the surrounding
compressor continues to consume C-shaped sequence and entropy-table storage.
Test Plan:
- cargo clippy
- cargo clippy --benches
- cargo clippy --tests
- cargo +nightly fmt
- cargo test --all-targets
- cargo test --target i686-unknown-linux-gnu zstd_compress_sequences::tests
- C-vs-Rust differential across 163 payload cases on x86_64 and i686
- fuzzer, zstreamtest, and invalidDictionaries
Refs: Rust FSE compression port 5f9d607d
Link poolTests against the multithreaded object set and Rust static archive,
so its C callbacks exercise the migrated pool rather than compiling a private
C implementation. Preserve ZSTD_MULTITHREAD for the test translation unit;
without it, its pthread test helpers become no-ops while the Rust pool runs
concurrently. Add a Rust regression for draining a small queue after reducing
the worker limit.
Test Plan:
- cargo clippy
- cargo clippy --benches
- cargo clippy --tests
- cargo +nightly fmt
- cargo test shrinking_the_limit_keeps_draining_a_small_queue -- --nocapture
- make -B -C tests poolTests && timeout 20s stdbuf -oL ./tests/poolTests
Refs: Rust pool migration 26b5e202
Move raw, RLE, and Huffman literal-section encoding into the Rust
compatibility archive. The surrounding C block compressor continues to pass
its existing entropy workspace and Huffman-table state through the unchanged
internal ABI.
The port preserves literal header choices, compression-gain decisions,
repeat-table transitions, and 1X/4X encoder selection. It lets ordinary C
compression paths exercise Rust code without widening this commit into the
remaining frame compressor.
Test Plan:
- cargo clippy, cargo clippy --benches, cargo clippy --tests, and nightly fmt
- cargo test --all-targets (94 passed) and feature-only cargo checks
- native fuzzer, zstreamtest, invalidDictionaries, and CLI round trip
- compare literals and next-table bytes with pristine C on x86_64 and i686
Refs: rust/README.md compression-primitives map
Move Huffman table construction, table serialization, and one- and
four-stream payload encoding from huf_compress.c into the Rust compatibility
archive. The declaration-only C shim preserves the existing internal ABI,
so the remaining C compressor can call the migrated implementation unchanged.
The translation keeps CTable layouts, workspace checks, repeat-table
selection, and bitstream output compatible with the original encoder. This
lets native C consumers exercise the Rust implementation through libzstd.
Test Plan:
- cargo clippy, cargo clippy --benches, and cargo clippy --tests
- cargo +nightly fmt and cargo test --all-targets (88 passed)
- cargo check --no-default-features --features compression
- rebuild and run tests fuzzer, zstreamtest, and invalidDictionaries
- compare tables, headers, and 1X/4X streams with a renamed pristine C build
Refs: rust/README.md component map
Build feature-matched Rust archives for the native Make library path. Flatten
their members into libzstd.a so static consumers resolve C-to-Rust and
Rust-to-C references in one archive, and whole-archive link shared outputs so
every migrated public ABI export remains available.
Rust compression and decompression features now mirror the C partial-library
switches. This prevents compression-only artifacts from retaining DDict
references to decompression-only C helpers.
Add a C archive smoke test that round-trips data and exercises the DDict
lifecycle through lib/libzstd.a, rather than direct test-object links.
Test Plan:
- cargo fmt, strict Clippy, cargo test --all-targets, release build
- Rust checks with compression-only, decompression-only, and no features
- full, partial, forced-HUF, and 32-bit static/shared Make library probes
- test-rust-lib-smoke, fuzzer, zstreamtest, and invalidDictionaries
Refs: rust/README.md
Move ZSTD_splitBlock into Rust while retaining its caller-owned workspace
contract. The implementation preserves the C fingerprint sampling heuristic
and calls the migrated histogram primitive without adding a hot-path
allocation.
Reference-vector and randomized differential tests compare every split level
with the original C translation unit. The C source remains as a declaration
shim so existing source lists resolve the Rust ABI during the migration.
Test Plan:
- cargo fmt, cargo clippy, cargo clippy --benches, cargo clippy --tests
- cargo test --all-targets and cargo build --release
- cargo test/build --target i686-unknown-linux-gnu
- 264-case original-C/Rust differential harness
- C fuzzer, zstreamtest, and fuzzer32 smoke runs
Refs: rust/README.md
Move ZSTD_DDict allocation, ownership, construction, and public ABI exports
into Rust. The C decoder keeps ZSTD_loadDEntropy until its table loader moves.
The C shim now exposes C-computed DCtx field offsets. This keeps dictionary
state correct across conditional C layouts, including fuzz fields and 32-bit
static-BMI2 builds, without duplicating decoder-context layout in Rust.
Test Plan:
- cargo fmt, cargo clippy, cargo clippy --benches, cargo clippy --tests
- cargo test --all-targets and cargo build --release
- cargo test/build --target i686-unknown-linux-gnu
- C fuzzer, zstreamtest, invalidDictionaries, and fuzzer32 smoke runs
- fuzz-enabled and i686 -mbmi2 C/Rust dictionary roundtrip harnesses
Refs: rust/README.md
Mode-specific Rust archives exposed the test makefiles' flat C-object cache:
switching from default to forced HUF mode could relink stale default C objects
with a newly built forced Rust archive. That hybrid has incompatible decoder
table expectations and can corrupt dictionary decompression.
Track each makefile's effective HUF mode with an empty archive stamp. It is a
safe normal linker prerequisite, and every mode transition advances its mtime
so cached C objects and direct-source binaries rebuild while unchanged modes
remain incremental.
Test Plan:
- cargo clippy; cargo clippy --benches; cargo clippy --tests
- cargo +nightly fmt, then repeat the Clippy checks
- cargo test --all-targets
- Default -> forced-X1 -> default fuzzer builds without -B, each running
./fuzzer -s5346 -i1 --no-big-tests
- Equivalent zstd-small default/forced/default rebuild and --version checks
Refs: rust/README.md
Fixes: d89ebb31
Move Huffman decoding-table construction and X1/X2 single- and four-stream
decoding into Rust. The original C translation unit is now a declaration shim,
so unchanged C callers and tests resolve the public decoder ABI from the Rust
archive.
The portable implementation preserves the C workspace and error contracts,
retains the existing assembly-only internal fast loops, and mirrors the C
32-bit decode cadence so X2 writes remain within its required output window.
Forced X1/X2 modes follow the matching archive configuration from the build
integration.
Test Plan:
- cargo clippy; cargo clippy --benches; cargo clippy --tests
- cargo +nightly fmt, then repeat the Clippy checks
- cargo test --all-targets for default, forced X1, and forced X2 modes
- cargo build and cargo test for i686-unknown-linux-gnu in all three modes
- Strict normal, X1, and X2 C shim compilation
- Original fuzzer and fullbench compatibility targets
Refs: rust/README.md
Depends-on: d89ebb31
Derive the Rust static-library configuration from the effective C HUF decoder
flags and place each mode in its own Cargo target directory. This prevents a
forced X1/X2 C build from silently reusing the default Rust archive.
The test and program makefiles now also build and link an i686 Rust archive
for their 32-bit targets, including zstd32. zstd-small retains its existing
default configuration while preserving an explicitly requested HUF mode.
Test Plan:
- cargo clippy; cargo clippy --benches; cargo clippy --tests
- cargo +nightly fmt, then repeat the Clippy checks
- cargo test --all-targets for default, forced X1, and forced X2 modes
- cargo build --release --target i686-unknown-linux-gnu for each mode
- make -n checks for default, forced, direct -D, and 32-bit test/CLI targets
Refs: rust/README.md
Use an explicitly 64-bit literal before narrowing it in the common-byte test,
and derive the FSE compression-bound expectation from `size_of::<usize>()`.
The tests now exercise the same public contracts on 32-bit and 64-bit targets
instead of embedding a 64-bit-only compile-time assumption.
Test Plan:
- cargo clippy; cargo clippy --benches; cargo clippy --tests
- cargo +nightly fmt, then repeat the Clippy checks
- cargo test --target i686-unknown-linux-gnu --lib
- cargo test --target i686-unknown-linux-gnu --lib --features \
huf-force-decompress-x1
- cargo test --target i686-unknown-linux-gnu --lib --features \
huf-force-decompress-x2
Refs: rust/README.md
Move FSE normalization, count-header writing, compression-table construction,
and stream encoding from C to Rust. The original C source remains as a
header-only shim, preserving the public header configuration while native
consumers receive the Rust archive exports.
This completes both codec directions for FSE in the migration crate and lets
the unchanged C compatibility tests exercise the Rust encoder implementation.
Test Plan:
- cargo clippy; cargo clippy --benches; cargo clippy --tests
- cargo +nightly fmt, then repeat the Clippy checks
- cargo test --all-targets
- cargo build --release
- Compile the C shim with strict warnings enabled
- 1,000-case pristine-C differential for tables, headers, and payloads
- ./tests/fuzzer -v -T10s
- ./tests/decodecorpus -t -T5
Refs: rust/README.md
Make Rust sources normal prerequisites of native C test executables and CLI
builds. A changed Rust module now rebuilds libzstd_rs.a and relinks the target,
instead of relying on a manually prepared archive that can silently be stale.
The archive is linked after C objects, allowing migrated C shims to resolve
their Rust ABI symbols while remaining compatible with the existing makefile
flows. The migration guide now documents this behavior.
Test Plan:
- make -B -C tests fuzzer
- ./tests/fuzzer -i1 --no-big-tests
- make -B -C programs zstd
- ./programs/zstd --version
Refs: rust/README.md
Move byte histogram counting into Rust for FSE and Huffman compression callers.
The implementation preserves the C workspace contract, checked alphabet path,
fast path, empty-input behavior, and C ABI while the original C source becomes
a header-only compatibility shim.
Focused tests cover count accumulation, invalid alphabets, workspace failures,
and striped large inputs. Higher-level compression remains C for now.
Test Plan:
- cargo fmt --check
- cargo test --all-targets
- cargo clippy --all-targets -- -D warnings
- cargo build --release
- make -C tests fuzzer
- ./tests/fuzzer -i1 --no-big-tests
- compile hist.c with -Werror and -Wredundant-decls
Refs: rust/README.md
Replace the common worker pool and debug pthread wrappers with ABI-compatible
Rust implementations. The pool preserves bounded-queue, resize, drain-on-free,
custom-allocator, and no-thread behavior while C supplies only the build-time
multithreading configuration bit.
This moves runtime support without changing C tests or public headers. Codec
and CLI implementations remain C while their dependencies are migrated.
Test Plan:
- cargo fmt --check
- cargo test --all-targets
- cargo clippy --all-targets -- -D warnings
- cargo build --release
- make -C tests poolTests
- ./tests/poolTests
- compile pool and threading shims with -Werror in MT and no-thread modes
Refs: rust/README.md
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
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
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