Keep the private CDict and CCtx parameter layouts in C while passing only the
five scalar inputs needed by the dictionary-attachment heuristic. Rust now
owns the exact per-strategy cutoffs and preserves unknown-size handling,
dedicated-search short-circuiting, force-attach and force-copy precedence, and
the force-window prohibition. The existing C helper and reset/copy call paths
remain unchanged.
Test Plan:
- `cargo test --manifest-path rust/Cargo.toml --no-default-features --features compression dictionary_attachment` -- passed (2 tests)
- `make -B -C lib -j2 lib` -- passed
- `make -C tests -j2 fuzzer` -- passed
- `./tests/fuzzer -s4560 -t47 -i48 -v` -- passed
- Rust clippy for the library, benches, and tests before and after nightly formatting -- passed
- `cargo +nightly fmt --manifest-path rust/Cargo.toml` -- passed
- `git diff --cached --check` -- passed
Keep dedicated-dictionary strategy dispatch, parameter selection, and call-site
control flow in C while routing only the hashLog field transformations through
scalar Rust ABI helpers. The helpers use wrapping u32 arithmetic so overflow
and the existing subtract-then-clamp behavior remain identical to C.
Test Plan:
- `cargo test --manifest-path rust/Cargo.toml --no-default-features --features compression dedicated_dict_search_hash_log_adjustments_match_strategy_cases` -- passed
- `make -B -C lib -j2 lib` -- passed
- `make -C tests -j2 fuzzer` -- passed
- `./tests/fuzzer -s4560 -t47 -i48 -v` -- passed
- clippy normal, benches, and tests before and after formatting -- passed
- `cargo +nightly fmt --manifest-path rust/Cargo.toml` and `git diff --check` -- passed
Keep the private writeBlockHeader signature and its debug logging in C while
moving the pure block-type, size, and 24-bit little-endian encoding behind a
narrow Rust ABI. The Rust leaf preserves the RLE blockSize path for cSize == 1
and the compressed cSize path for every other value.
Test Plan:
- `cargo test --manifest-path rust/Cargo.toml --no-default-features --features compression block_header -- --nocapture` -- passed
- `make -B -C lib -j2 lib` -- passed
- `make -C tests -j2 fuzzer` -- passed
- `./tests/fuzzer -s4560 -t47 -i48 -v` -- passed
- Required clippy, nightly fmt, and diff checks -- passed
ZSTD_compressCCtx was selecting the Rust frame path for every compression
level. For source sizes that resolve to lazy or optimal strategies, that path
fell through to fast matching and could produce a different frame, including
the CCtx reuse regression caught by fuzzer test 56.
Query the source-size-dependent C parameters before preparing the context.
Keep fast and double-fast strategies on the existing Rust path, while routing
all other strategies through ZSTD_compress_usingDict with no dictionary so the
original simple API initializes requested parameters and C match state.
Test Plan:
- `make -B -C tests -j2 fuzzer` -- passed
- `./tests/fuzzer -s4560 -t56 -i56 -v` -- passed
- `cargo test --manifest-path rust/Cargo.toml --no-default-features --features compression` -- 253 passed
- required clippy normal, benches, and tests checks -- passed
- `cargo +nightly fmt --manifest-path rust/Cargo.toml` -- passed
- `git diff --check` and `git diff --cached --check` -- passed
ZSTD_resolveExternalSequenceValidation() is a pure int identity used while
resolving CCtx parameters. Route its existing C wrapper through a Rust
extern "C" entry point in the parameter module, preserving the int-to-int
ABI and every call-site result. Add boundary coverage for signed int modes.
Test Plan:
- `cargo test --manifest-path rust/Cargo.toml --no-default-features --features compression` -- passed (253 tests)
- `make -B -C lib -j2 lib` -- passed
- required clippy passes for the compression feature, benches, and tests -- passed
- `cargo +nightly fmt --manifest-path rust/Cargo.toml` and `git diff --check` -- passed
The compression-parameter override helper previously lived in C and selectively
copied each nonzero field from a caller-provided override structure. Move that
pure field-wise operation into the Rust compression-parameter module, while
keeping the existing repr(C) structure and pointer-based ABI at both C call
sites. Zero-valued overrides continue to leave the current parameter untouched.
Test Plan:
- `cargo test --manifest-path rust/Cargo.toml --no-default-features --features compression` -- passed (252 tests)
- `make -B -C lib -j2 lib` -- passed
- `make -C tests -j2 fuzzer` and `tests/fuzzer -s4560 -t47 -i48 -v` -- passed
- required clippy passes, nightly fmt, and `git diff --check` -- passed
Keep validation of the applied compression parameters in C and delegate the context-free minimum calculation through a narrow ABI leaf. Preserve the public getter and deprecated block-compression paths.
Test Plan:
- cargo test --manifest-path rust/Cargo.toml --no-default-features --features compression
- cargo clippy --manifest-path rust/Cargo.toml --no-default-features --features compression --all-targets
- cargo +nightly fmt --manifest-path rust/Cargo.toml
- make -B -C lib -j2 lib
- make -C tests -j2 fuzzer
- tests/fuzzer -s4560 -t47 -i48 -v
Keep C ownership of the block-state structure while delegating the confirmed-block pointer swap through a narrow two-pointer ABI leaf. Preserve every existing confirmation call site and add direct pointer-swap coverage.
Test Plan:
- cargo test --manifest-path rust/Cargo.toml --no-default-features --features compression
- cargo clippy --manifest-path rust/Cargo.toml --no-default-features --features compression --all-targets
- cargo +nightly fmt --manifest-path rust/Cargo.toml
- make -B -C lib -j2 lib
- tests/fuzzer -s4560 -t47 -i48 -v
- make -C tests -j2 test-zstream
Parse attached and separated --patch-from references, preserve the upstream ultra ceiling and conflict checks, and pass the reference path through the existing file-I/O dictionary ABI with patch mode enabled.
Test Plan:
- cargo test --manifest-path rust/cli/Cargo.toml
- cargo clippy --manifest-path rust/cli/Cargo.toml --all-targets
- cargo +nightly fmt --manifest-path rust/Cargo.toml
- make -C tests -j2 check
- small attached/separate patch-from round-trip and rejection smoke
Port the no-delimiter external-sequence block scanner, match splitting, repcode updates, validation, and sequence/literal storage behind a narrow C shim. Preserve trailing bytes as literals when the sequence buffer ends before the requested block, and remove the obsolete C validation wrapper.
Test Plan:
- cargo test --manifest-path rust/Cargo.toml --no-default-features --features compression (242 passed)
- cargo clippy --manifest-path rust/Cargo.toml --no-default-features --features compression [--benches|--tests] (clean)
- cargo +nightly fmt --manifest-path rust/Cargo.toml (clean)
- make -B -C lib -j2 lib (passed)
- make -C tests -j2 test-zstream (84 deterministic; 5960 and 8307 randomized passed)
- make -C tests -j2 test-fuzzer (existing test 56 CCtx-reuse mismatch; also fails at 37eb75758)
- make -C tests -j2 test-zstd (existing Rust CLI --patch-from gap)
Port ZSTD_dictNCountRepeat and ZSTD_loadCEntropy to a dedicated Rust compression module. Preserve the existing C-facing ZSTD_loadCEntropy symbol through a narrow shim while keeping dictionary content and compression-context ownership in C.
Test Plan:
- cargo test --manifest-path rust/Cargo.toml --no-default-features --features compression
- cargo clippy --manifest-path rust/Cargo.toml --no-default-features --features compression --benches --tests
- make -B -C lib -j2 lib
- make -C tests -j2 test-invalidDictionaries
- make -C tests -j2 test-zstream
Move ZSTD_transferSequences_wBlockDelim's delimiter scan, literal copying, SeqDef storage, validation, and repcode bookkeeping into the Rust compression statistics module. Keep ZSTD_CCtx and block-state ownership in C through a narrow scalar/pointer shim, with ABI layout assertions for ZSTD_SequencePosition.
Test Plan:
- cargo test --manifest-path rust/Cargo.toml --no-default-features --features compression
- cargo clippy --manifest-path rust/Cargo.toml --no-default-features --features compression --benches --tests
- make -B -C lib -j2 lib
- make -C tests -j2 test-zstream
Block splitting still estimated literal and sequence section sizes through
three C helpers. Move the pure estimator into zstd_compress_stats.rs so its
histogram, HUF, and FSE cost calculations use the Rust implementations already
behind the compression ABI. Preserve the original literal headers, multi-stream
Huffman surcharge, sequence additional-bit costs, entropy-header accounting,
and fallback estimates; leave C responsible for split recursion and table
ownership.
Test Plan:
- `cargo test --manifest-path rust/Cargo.toml --no-default-features --features compression` -- 229 passed
- `cargo clippy --manifest-path rust/Cargo.toml --no-default-features --features compression` plus benches/tests -- passed before and after formatting
- `cargo +nightly fmt --manifest-path rust/Cargo.toml --all` -- passed
- `make -B -C lib -j2 lib` -- passed
- `make -C tests -j2 test-zstream` -- passed, including 84 deterministic and 15,375 randomized cases
The explicit-delimiter sequence path still calculated each block summary in C,
with a separate AVX2 implementation and scalar fallback. Move that pure scan
to zstd_compress_stats.rs and keep a C wrapper for the existing orchestration.
The Rust leaf preserves delimiter inclusion, literal and match totals, and the
external-sequences error when no delimiter is present, while the C ABI is pinned
with a repr(C) layout check.
Test Plan:
- `cargo test --manifest-path rust/Cargo.toml --no-default-features --features compression` -- 227 passed
- `cargo clippy --manifest-path rust/Cargo.toml --no-default-features --features compression` plus benches/tests -- passed before and after formatting
- `cargo +nightly fmt --manifest-path rust/Cargo.toml --all` -- passed
- `make -B -C lib -j2 lib` -- passed
- `make -C tests -j2 test-zstream` -- passed, including 84 deterministic and 15,464 randomized cases
The external-sequence block path still converted public ZSTD_Sequence values
in C, with separate scalar and AVX2 implementations. Move that pure format
conversion into zstd_compress_stats.rs so both native configurations share one
implementation. Preserve offBase encoding, u16 truncation, the rep-ignored
contract, and the long-length side-band marker; leave C responsible for block
state, repcode resolution, and long-length bookkeeping.
Test Plan:
- `cargo test --manifest-path rust/Cargo.toml --no-default-features --features compression` -- 225 passed
- `cargo clippy --manifest-path rust/Cargo.toml --no-default-features --features compression` plus benches/tests -- passed before and after formatting
- `cargo +nightly fmt --manifest-path rust/Cargo.toml --all` -- passed
- `make -B -C lib -j2 lib` -- passed
- `make -C tests -j2 test-zstream` -- passed, including 84 deterministic and 14,768 randomized cases
Port ZSTD_seqStore_resolveOffCodes and its repcode-resolution helper to Rust. The C shim keeps Repcodes_t and SeqStore_t ownership in the compressor context while Rust preserves long-literal handling, mismatch materialization, and independent decoder/compressor history updates.
Test Plan:
- cargo test --manifest-path rust/Cargo.toml --no-default-features --features compression (208 tests)
- cargo clippy --manifest-path rust/Cargo.toml
- cargo clippy --manifest-path rust/Cargo.toml --benches
- cargo clippy --manifest-path rust/Cargo.toml --tests
- make -B -C lib -j2 lib
Replace the shared C raw and one-byte RLE fallback block serializers with Rust ABI leaves. Preserve the zstd block headers, payload copies, capacity errors, and all existing C compressor dispatch and context ownership; share the raw serializer with the Rust one-shot path.
Test Plan:
- cargo test --manifest-path rust/Cargo.toml --no-default-features --features compression (208 tests)
- cargo clippy --manifest-path rust/Cargo.toml
- cargo clippy --manifest-path rust/Cargo.toml --benches
- cargo clippy --manifest-path rust/Cargo.toml --tests
- make -B -C lib -j2 lib
Move malloc-backed dictionary file reads into the Rust CLI backend while keeping C responsible for stat metadata, patch-mode size policy, diagnostics, buffer-type selection, and eventual free(). The Rust leaf returns explicit open, size, allocation, and read statuses and publishes only fully read libc allocations.
Test Plan:
- cargo test --manifest-path rust/cli/Cargo.toml (126 tests)
- cargo clippy --manifest-path rust/cli/Cargo.toml
- make -B -C programs -j2 zstd
- make -C tests -j2 test-cli-tests (41 tests)
Port the scalar frame-finalization policy and byte serialization into the Rust compression leaf while keeping checksum finalization, tracing, and the compression context in C. Preserve the init-to-ongoing transition on partial failure and reset the stage only after a successful epilogue.
Test Plan:
- cargo test --manifest-path rust/Cargo.toml --no-default-features --features compression
- cargo clippy --manifest-path rust/Cargo.toml
- cargo clippy --manifest-path rust/Cargo.toml --benches
- cargo clippy --manifest-path rust/Cargo.toml --tests
- make -B -C lib -j2 lib
- make -B -C tests -j2 test-zstream (84 deterministic, 6737 and 9012 fuzzer cases)
Route the CLI backend's safe file-removal leaf through a narrow Rust status ABI while preserving C diagnostics, Windows read-only handling, and the existing return convention.
Test Plan: cargo test --manifest-path rust/cli/Cargo.toml; cargo clippy --manifest-path rust/cli/Cargo.toml; cargo clippy --manifest-path rust/cli/Cargo.toml --benches; cargo clippy --manifest-path rust/cli/Cargo.toml --tests; make -B -C programs -j2 zstd; make -C tests -j2 test-cli-tests (41 tests); make -B -C programs -j2 zstd-small zstd-frugal.
Port the external-sequence window, offset, and minimum-match checks through a scalar C ABI leaf while retaining the C caller's control flow and diagnostics.
Test Plan: cargo test --manifest-path rust/Cargo.toml --no-default-features --features compression; cargo clippy --manifest-path rust/Cargo.toml; cargo clippy --manifest-path rust/Cargo.toml --benches; cargo clippy --manifest-path rust/Cargo.toml --tests; make -B -C lib -j2 lib; make -B -C tests -j2 test-zstream (84 deterministic, 7063 and 8665 fuzzer cases).
Move ZSTD_isUpdateAuthorized behind the existing Rust parameter API while retaining the C context-stage checks, diagnostics, and mutation flow.
Test Plan:
- cargo test --manifest-path rust/Cargo.toml --no-default-features --features compression (187 tests)
- cargo clippy for library, benches, and tests
- make -B -C lib -j2 lib
Move the CLI's strategy-dependent cycle-log calculation behind a scalar Rust ABI shim while retaining the C assertion and call-site behavior.
Test Plan:
- cargo test --manifest-path rust/cli/Cargo.toml --no-default-features --features cli,compression,decompression,benchmark (116 tests)
- cargo clippy --manifest-path rust/cli/Cargo.toml --all-targets with the full CLI feature set
- make -B -C programs -j2 zstd zstd-small zstd-frugal
- make -C tests -j2 test-cli-tests (41 scenarios)
Move hash-salt mixing and context-reset overflow predicates behind scalar Rust ABI shims. Keep the C-owned match state and window arithmetic in the C wrapper while preserving exact architecture-dependent thresholds.
Test Plan:
- cargo test --manifest-path rust/Cargo.toml --no-default-features --features compression (186 tests)
- cargo clippy for library, benches, tests, and CLI all-targets
- make -B -C lib -j2 lib
- make -B -C tests -j2 test-zstream (84 deterministic tests; fuzzers 6451 and 9879 cases)
Move patch-from memory-limit sizing and rejection status selection behind a Rust ABI shim. Keep the C diagnostics and assertion in place, and leave the existing preference unchanged when input sizes are unknown or exceed the window limit.
Test Plan:
- cargo test --manifest-path rust/cli/Cargo.toml --no-default-features --features cli,compression,decompression,benchmark (113 tests)
- cargo clippy --manifest-path rust/cli/Cargo.toml --all-targets with the CLI feature set
- make -B -C programs -j2 zstd zstd-small zstd-frugal
- make -C tests -j2 test-cli-tests (41 scenarios) and make -B -C tests -j2 test-zstream
Move target block-size and block-splitter policy predicates behind narrow Rust ABI shims while retaining the C debug logging, finalized-mode assertion, and surrounding control flow.
Test Plan:
- cargo test --manifest-path rust/Cargo.toml --no-default-features --features compression
- cargo clippy --manifest-path rust/Cargo.toml and native library build
- make -B -C tests -j2 test-zstream (84 deterministic tests; fuzzers 6778 and 8299 cases)
Port the single-file and multiple-file summary decisions through the existing FIO context ABI, including the display-level lookup and the original multiple-file assertion invariant. Keep the C wrappers and call sites unchanged.
Test Plan: cargo test --manifest-path rust/cli/Cargo.toml --no-default-features --features cli,compression,decompression,benchmark (108 passed); CLI all-target clippy; make -B -C programs -j2 zstd zstd-small zstd-frugal; make -C tests -j2 test-cli-tests (41 passed).
Move construction of the external-dictionary and active-prefix ranges into a narrow Rust ABI while retaining the C window and logging surface. Preserve byte-range half-open overlap semantics and leave the input-range overlap wrapper available to its other C caller.
Test Plan: cargo test --manifest-path rust/Cargo.toml --no-default-features --features compression (180 passed); root and CLI clippy; make -B -C lib -j2 lib; make -C tests -j2 test-cli-tests (41 passed); make -B -C tests -j2 test-zstream (84 named tests plus 6,845 and 9,628 fuzz cases passed).
Port the 16-cell match-table reduction leaf while preserving the window-index threshold, wrapping subtraction, and btlazy2 unsorted marker. Keep ZSTD_reduceIndex and its strategy-specific table selection in C behind the narrow Rust ABI.
Test Plan: cargo test --manifest-path rust/Cargo.toml --no-default-features --features compression (180 passed); root clippy, bench clippy, and test clippy; make -B -C lib -j2 lib; make -B -C tests -j2 test-zstream (84 named tests plus 6,845 and 9,628 fuzz cases passed).
Mirror fileio.c's private fileInfo_t with a checked repr(C) ABI and aggregate totals, flags, and file counts through an output-pointer shim. Preserve zeroed non-aggregate fields and use wrapping arithmetic for the original integer operations.
Test Plan: cargo test --manifest-path rust/cli/Cargo.toml --no-default-features --features cli,compression,decompression,benchmark (106 passed); cargo clippy --all-targets with the same features; make -B -C programs -j2 zstd zstd-small zstd-frugal; make -C tests -j2 test-cli-tests (41 passed).
Port repcode offBase finalization and explicit-delimiter block sizing through the Rust compression ABI. Preserve wrapped sequence arithmetic, external-sequence error codes, and the no-delimiter target-size policy while keeping the C control flow intact.
Test Plan: cargo test --manifest-path rust/Cargo.toml --no-default-features --features compression (176 passed); cargo clippy root, benches, and tests; make -B -C lib -j2 lib; make -B -C tests -j2 test-zstream (84 named tests plus 6,230 and 8,598 fuzz cases passed).
Move sequence-store byte accounting, chunk derivation, and repcode resolution into the Rust compression module. Move MT raw-sequence buffer conversions into Rust while preserving the existing C adapters and ABI layouts.
Test Plan:\n- cargo test --manifest-path rust/Cargo.toml --no-default-features --features compression\n- cargo clippy --manifest-path rust/Cargo.toml\n- cargo clippy --manifest-path rust/Cargo.toml --benches\n- cargo clippy --manifest-path rust/Cargo.toml --tests\n- make -B -C lib -j2 lib\n- make -B -C tests -j2 test-cli-tests
Route file-I/O input/output buffer construction and the LZ4 block-size mapping through Rust ABI leaves while preserving the existing C helper names and public buffer layouts. Add layout, field, and formula coverage.
Test Plan: cargo test --manifest-path rust/cli/Cargo.toml --no-default-features --features cli,compression,decompression,benchmark; cargo clippy --manifest-path rust/cli/Cargo.toml --all-targets --no-default-features --features cli,compression,decompression,benchmark; make -B -C programs -j2 zstd zstd-small zstd-frugal; make -B -C tests -j2 test-cli-tests
Route public CCtx parameter bounds through the Rust policy implementation while keeping build-specific MT limits supplied by the C configuration. Preserve clamping and validation behavior for migrated parameters and add focused Rust coverage.
Test Plan: cargo test --manifest-path rust/Cargo.toml --no-default-features --features compression; cargo clippy --manifest-path rust/Cargo.toml; cargo clippy --manifest-path rust/Cargo.toml --benches; cargo clippy --manifest-path rust/Cargo.toml --tests; make -B -C lib -j2 lib; make -B -C tests -j2 test-cli-tests; make -B -C tests -j2 test-zstream
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