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feat(compress): move dedicated dict get params to Rust

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Port the final strategy-dependent transform in
ZSTD_dedicatedDictSearch_getCParams to a Rust ABI leaf that accepts and
returns the complete repr(C) compression-parameter struct. Keep C responsible
for ZSTD_getCParams_internal table selection and adjustment, including the
createCDict mode and its existing call order, as well as all dictionary and
context construction. The Rust leaf changes only hashLog for greedy, lazy,
and lazy2; every other and unexpected strategy is preserved unchanged.

Remove the obsolete scalar hash-log C ABI now that the complete-parameter
boundary is used. The focused Rust tests cover every strategy class and
unexpected values, field preservation, wrapping adjustment boundaries, and
the existing reverse transform's subtraction/clamp behavior.

Test Plan:
- `cargo test --manifest-path rust/Cargo.toml --no-default-features --features compression zstd_compress_params` -- passed (37 tests)
- `cargo clippy --manifest-path rust/Cargo.toml --no-default-features --features compression` -- passed before and after formatting
- `cargo clippy --manifest-path rust/Cargo.toml --no-default-features --features compression --benches` -- passed before and after formatting
- `cargo clippy --manifest-path rust/Cargo.toml --no-default-features --features compression --tests` -- passed before and after formatting
- `cargo +nightly fmt --manifest-path rust/Cargo.toml` -- passed
- `make -B -C lib -j2 lib` -- passed
- `make -C tests test-rust-lib-smoke` -- passed
- `make -B -C tests -j2 fuzzer` -- passed
- `tests/fuzzer -s4560 -t56 -i57 -v` -- passed
- `make -C tests -j2 test-zstream` -- passed (84 named tests; randomized phases of 6,557 and 7,884 cases)
- `git diff --check` and `git diff --cached --check` -- passed
This commit is contained in:
ddidderr
2026-07-18 10:56:28 +02:00
parent a895506e78
commit 21431587fa
2 changed files with 95 additions and 23 deletions
Download Patch File Download Diff File Expand all files Collapse all files
lib/compress/zstd_compress.c
+5 -18
View File
@@ -139,7 +139,8 @@ int ZSTD_rust_params_resolveEnableLdm(
int ZSTD_rust_params_resolveExternalRepcodeSearch(int mode, int cLevel);
int ZSTD_rust_params_cdictIndicesAreTagged(ZSTD_compressionParameters cParams);
int ZSTD_rust_params_dedicatedDictSearchIsSupported(ZSTD_compressionParameters cParams);
U32 ZSTD_rust_params_dedicatedDictSearch_getHashLog(U32 hashLog);
ZSTD_compressionParameters
ZSTD_rust_params_dedicatedDictSearch_getCParams(ZSTD_compressionParameters cParams);
ZSTD_compressionParameters
ZSTD_rust_params_dedicatedDictSearch_revertCParams(ZSTD_compressionParameters cParams);
int ZSTD_rust_params_shouldAttachDict(int strategy, int dedicatedDictSearch,
@@ -5654,23 +5655,9 @@ int ZSTD_defaultCLevel(void) { return ZSTD_rust_params_defaultCLevel(); }
static ZSTD_compressionParameters ZSTD_dedicatedDictSearch_getCParams(int const compressionLevel, size_t const dictSize)
{
ZSTD_compressionParameters cParams = ZSTD_getCParams_internal(compressionLevel, 0, dictSize, ZSTD_cpm_createCDict);
switch (cParams.strategy) {
case ZSTD_fast:
case ZSTD_dfast:
break;
case ZSTD_greedy:
case ZSTD_lazy:
case ZSTD_lazy2:
cParams.hashLog = ZSTD_rust_params_dedicatedDictSearch_getHashLog(cParams.hashLog);
break;
case ZSTD_btlazy2:
case ZSTD_btopt:
case ZSTD_btultra:
case ZSTD_btultra2:
break;
}
return cParams;
ZSTD_compressionParameters const cParams =
ZSTD_getCParams_internal(compressionLevel, 0, dictSize, ZSTD_cpm_createCDict);
return ZSTD_rust_params_dedicatedDictSearch_getCParams(cParams);
}
/**
rust/src/zstd_compress_params.rs
+90 -5
View File
@@ -448,6 +448,19 @@ fn dedicated_dict_search_get_hash_log(hash_log: u32) -> u32 {
hash_log.wrapping_add(ZSTD_LAZY_DDSS_BUCKET_LOG)
}
#[inline]
fn dedicated_dict_search_get_cparams(
mut cparams: ZSTD_compressionParameters,
) -> ZSTD_compressionParameters {
match cparams.strategy {
ZSTD_GREEDY | ZSTD_LAZY | ZSTD_LAZY2 => {
cparams.hashLog = dedicated_dict_search_get_hash_log(cparams.hashLog);
}
_ => {}
}
cparams
}
#[inline]
fn dedicated_dict_search_revert_hash_log(hash_log: u32) -> u32 {
hash_log
@@ -538,10 +551,12 @@ pub extern "C" fn ZSTD_rust_params_dedicatedDictSearchIsSupported(
c_int::from(dedicated_dict_search_is_supported(cparams))
}
/// C ABI for the hash-log adjustment used by `ZSTD_dedicatedDictSearch_getCParams()`.
/// C ABI for `ZSTD_dedicatedDictSearch_getCParams()`.
#[no_mangle]
pub extern "C" fn ZSTD_rust_params_dedicatedDictSearch_getHashLog(hash_log: u32) -> u32 {
dedicated_dict_search_get_hash_log(hash_log)
pub extern "C" fn ZSTD_rust_params_dedicatedDictSearch_getCParams(
cparams: ZSTD_compressionParameters,
) -> ZSTD_compressionParameters {
dedicated_dict_search_get_cparams(cparams)
}
/// C ABI for `ZSTD_dedicatedDictSearch_revertCParams()`.
@@ -1437,7 +1452,7 @@ mod tests {
let should_adjust = matches!(strategy, ZSTD_GREEDY | ZSTD_LAZY | ZSTD_LAZY2);
let original = 12;
let adjusted = if should_adjust {
ZSTD_rust_params_dedicatedDictSearch_getHashLog(original)
dedicated_dict_search_get_hash_log(original)
} else {
original
};
@@ -1451,7 +1466,7 @@ mod tests {
assert_eq!(reverted, original);
}
assert_eq!(ZSTD_rust_params_dedicatedDictSearch_getHashLog(u32::MAX), 1);
assert_eq!(dedicated_dict_search_get_hash_log(u32::MAX), 1);
assert_eq!(
dedicated_dict_search_revert_hash_log(ZSTD_HASHLOG_MIN as u32),
ZSTD_HASHLOG_MIN as u32
@@ -1468,6 +1483,76 @@ mod tests {
assert_eq!(dedicated_dict_search_revert_hash_log(1), u32::MAX);
}
#[test]
fn dedicated_dict_search_get_cparams_preserves_fields_and_strategy_policy() {
let strategies = [
ZSTD_FAST,
ZSTD_DFAST,
ZSTD_GREEDY,
ZSTD_LAZY,
ZSTD_LAZY2,
ZSTD_BTLAZY2,
ZSTD_BTOPT,
ZSTD_BTULTRA,
ZSTD_BTULTRA2,
-1,
99,
];
for strategy in strategies {
let input = ZSTD_compressionParameters {
windowLog: 21,
chainLog: 19,
hashLog: 12,
searchLog: 5,
minMatch: 4,
targetLength: 48,
strategy,
};
let output = ZSTD_rust_params_dedicatedDictSearch_getCParams(input);
let expected_hash_log = if matches!(strategy, ZSTD_GREEDY | ZSTD_LAZY | ZSTD_LAZY2) {
14
} else {
input.hashLog
};
assert_eq!(output.hashLog, expected_hash_log, "strategy {strategy}");
assert_eq!(output.windowLog, input.windowLog, "strategy {strategy}");
assert_eq!(output.chainLog, input.chainLog, "strategy {strategy}");
assert_eq!(output.searchLog, input.searchLog, "strategy {strategy}");
assert_eq!(output.minMatch, input.minMatch, "strategy {strategy}");
assert_eq!(
output.targetLength, input.targetLength,
"strategy {strategy}"
);
assert_eq!(output.strategy, input.strategy, "strategy {strategy}");
}
for strategy in [ZSTD_GREEDY, ZSTD_LAZY, ZSTD_LAZY2] {
let mut input = ZSTD_compressionParameters {
hashLog: u32::MAX,
strategy,
..ZSTD_compressionParameters::default()
};
assert_eq!(
ZSTD_rust_params_dedicatedDictSearch_getCParams(input).hashLog,
1
);
input.hashLog = 0;
assert_eq!(
ZSTD_rust_params_dedicatedDictSearch_getCParams(input).hashLog,
2
);
input.hashLog = 1;
assert_eq!(
ZSTD_rust_params_dedicatedDictSearch_getCParams(input).hashLog,
3
);
}
}
#[test]
fn dedicated_dict_search_revert_cparams_preserves_fields_and_strategy_policy() {
let strategies = [