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feat(compress): move C parameter overrides to Rust

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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
This commit is contained in:
ddidderr
2026-07-18 08:40:32 +02:00
parent 33c937bc87
commit 0a06fa778c
2 changed files with 79 additions and 15 deletions
Download Patch File Download Diff File Expand all files Collapse all files
lib/compress/zstd_compress.c
+4 -15
View File
@@ -104,6 +104,8 @@ size_t ZSTD_rust_params_maxNbSeq(size_t blockSize, U32 minMatch,
int useSequenceProducer);
size_t ZSTD_rust_params_resolveMaxBlockSize(size_t maxBlockSize);
size_t ZSTD_rust_params_getBlockSize(size_t maxBlockSize, U32 windowLog);
void ZSTD_rust_params_overrideCParams(ZSTD_compressionParameters* cParams,
const ZSTD_compressionParameters* overrides);
int ZSTD_rust_params_rowMatchFinderSupported(int strategy);
int ZSTD_rust_params_rowMatchFinderUsed(int strategy, int mode);
int ZSTD_rust_params_resolveRowMatchFinderMode(
@@ -1158,19 +1160,6 @@ ZSTD_adjustCParams(ZSTD_compressionParameters cPar,
static ZSTD_compressionParameters ZSTD_getCParams_internal(int compressionLevel, unsigned long long srcSizeHint, size_t dictSize, ZSTD_CParamMode_e mode);
static ZSTD_parameters ZSTD_getParams_internal(int compressionLevel, unsigned long long srcSizeHint, size_t dictSize, ZSTD_CParamMode_e mode);
static void ZSTD_overrideCParams(
ZSTD_compressionParameters* cParams,
const ZSTD_compressionParameters* overrides)
{
if (overrides->windowLog) cParams->windowLog = overrides->windowLog;
if (overrides->hashLog) cParams->hashLog = overrides->hashLog;
if (overrides->chainLog) cParams->chainLog = overrides->chainLog;
if (overrides->searchLog) cParams->searchLog = overrides->searchLog;
if (overrides->minMatch) cParams->minMatch = overrides->minMatch;
if (overrides->targetLength) cParams->targetLength = overrides->targetLength;
if (overrides->strategy) cParams->strategy = overrides->strategy;
}
ZSTD_compressionParameters ZSTD_getCParamsFromCCtxParams(
const ZSTD_CCtx_params* CCtxParams, U64 srcSizeHint, size_t dictSize, ZSTD_CParamMode_e mode)
{
@@ -1181,7 +1170,7 @@ ZSTD_compressionParameters ZSTD_getCParamsFromCCtxParams(
}
cParams = ZSTD_getCParams_internal(CCtxParams->compressionLevel, srcSizeHint, dictSize, mode);
if (CCtxParams->ldmParams.enableLdm == ZSTD_ps_enable) cParams.windowLog = ZSTD_LDM_DEFAULT_WINDOW_LOG;
ZSTD_overrideCParams(&cParams, &CCtxParams->cParams);
ZSTD_rust_params_overrideCParams(&cParams, &CCtxParams->cParams);
assert(!ZSTD_checkCParams(cParams));
/* srcSizeHint == 0 means 0 */
return ZSTD_adjustCParams_internal(cParams, srcSizeHint, dictSize, mode, CCtxParams->useRowMatchFinder);
@@ -4131,7 +4120,7 @@ ZSTD_CDict* ZSTD_createCDict_advanced2(
if (cctxParams.enableDedicatedDictSearch) {
cParams = ZSTD_dedicatedDictSearch_getCParams(
cctxParams.compressionLevel, dictSize);
ZSTD_overrideCParams(&cParams, &cctxParams.cParams);
ZSTD_rust_params_overrideCParams(&cParams, &cctxParams.cParams);
} else {
cParams = ZSTD_getCParamsFromCCtxParams(
&cctxParams, ZSTD_CONTENTSIZE_UNKNOWN, dictSize, ZSTD_cpm_createCDict);
rust/src/zstd_compress_params.rs
+75
View File
@@ -905,6 +905,44 @@ fn get_block_size(max_block_size: usize, window_log: u32) -> usize {
max_block_size.min(1usize << window_log)
}
#[inline]
fn override_cparams(
cparams: &mut ZSTD_compressionParameters,
overrides: &ZSTD_compressionParameters,
) {
if overrides.windowLog != 0 {
cparams.windowLog = overrides.windowLog;
}
if overrides.hashLog != 0 {
cparams.hashLog = overrides.hashLog;
}
if overrides.chainLog != 0 {
cparams.chainLog = overrides.chainLog;
}
if overrides.searchLog != 0 {
cparams.searchLog = overrides.searchLog;
}
if overrides.minMatch != 0 {
cparams.minMatch = overrides.minMatch;
}
if overrides.targetLength != 0 {
cparams.targetLength = overrides.targetLength;
}
if overrides.strategy != 0 {
cparams.strategy = overrides.strategy;
}
}
/// Pure leaf for the private `ZSTD_overrideCParams()` helper.
#[no_mangle]
pub unsafe extern "C" fn ZSTD_rust_params_overrideCParams(
cparams: *mut ZSTD_compressionParameters,
overrides: *const ZSTD_compressionParameters,
) {
let (cparams, overrides) = unsafe { (&mut *cparams, &*overrides) };
override_cparams(cparams, overrides);
}
/// Pure leaf for the deprecated `ZSTD_getBlockSize()` path.
#[no_mangle]
pub extern "C" fn ZSTD_rust_params_getBlockSize(maxBlockSize: usize, windowLog: u32) -> usize {
@@ -1337,4 +1375,41 @@ mod tests {
assert_eq!(ZSTD_rust_params_getBlockSize(128 * 1024, 16), 64 * 1024);
assert_eq!(ZSTD_rust_params_getBlockSize(128 * 1024, 17), 128 * 1024);
}
#[test]
fn cparam_overrides_replace_only_nonzero_fields() {
let mut cparams = ZSTD_compressionParameters {
windowLog: 10,
chainLog: 11,
hashLog: 12,
searchLog: 13,
minMatch: 14,
targetLength: 15,
strategy: 16,
};
let overrides = ZSTD_compressionParameters {
windowLog: 20,
chainLog: 0,
hashLog: 22,
searchLog: 0,
minMatch: 24,
targetLength: 0,
strategy: 26,
};
unsafe { ZSTD_rust_params_overrideCParams(&mut cparams, &overrides) };
assert_eq!(
cparams,
ZSTD_compressionParameters {
windowLog: 20,
chainLog: 11,
hashLog: 22,
searchLog: 13,
minMatch: 24,
targetLength: 15,
strategy: 26,
}
);
}
}