feat(compress): move CDict begin policy into Rust

Move ZSTD_compressBegin_usingCDict_internal source-size parameter selection,
parameter initialization ordering, and source-window floor into a Rust-owned
ABI bridge while retaining private CCtx/CDict layouts and the final C begin
callback. Preserve strict cutoff, dictionary-size multiplier, unknown-size,
level-zero, and begin-error semantics.

Test Plan:
- cargo test --manifest-path rust/Cargo.toml --lib
- cargo clippy --manifest-path rust/Cargo.toml --all-targets -- -D warnings
- make -B -C programs -j1 zstd
- make -C tests -j1 test-zstream ZSTREAM_TESTTIME=-T1s
- focused cdict_begin unit tests
This commit is contained in:
2026-07-19 14:19:43 +02:00
parent 148af6d884
commit 4952b259c4
2 changed files with 535 additions and 29 deletions
+441
View File
@@ -15,10 +15,16 @@ use crate::entropy_common::FSE_readNCount;
use crate::errors::{ERR_isError, ZstdErrorCode, ERROR};
use crate::fse_compress::FSE_buildCTable_wksp;
use crate::huf_compress::HUF_readCTable;
use crate::zstd_compress_params::{
ZSTD_compressionParameters, ZSTD_frameParameters, ZSTD_parameters, ZSTD_rust_params_getCParams,
ZSTD_CONTENTSIZE_UNKNOWN,
};
use crate::zstd_compress_params_api::ZSTD_CCtx_params;
use crate::zstd_compress_stats::{
ZSTD_compressedBlockState_t, ZSTD_rust_resetCompressedBlockState,
};
use std::ffi::c_void;
use std::mem::{offset_of, size_of};
use std::os::raw::{c_int, c_short, c_uint};
use std::ptr;
use std::slice;
@@ -84,6 +90,148 @@ fn stage_wrong() -> usize {
ERROR(ZstdErrorCode::StageWrong)
}
type CompressBeginUsingCDictInitParamsFn =
unsafe extern "C" fn(*mut c_void, *const ZSTD_parameters, c_int);
type CompressBeginUsingCDictAdjustWindowFn = unsafe extern "C" fn(*mut c_void, c_uint);
type CompressBeginUsingCDictBeginFn =
unsafe extern "C" fn(*mut c_void, *const c_void, *const c_void, u64) -> usize;
/// Explicit projection for `ZSTD_compressBegin_usingCDict_internal`.
///
/// Rust owns CDict/source-size parameter selection, initialization ordering,
/// and the source-window floor. C retains the private parameter/context
/// layouts and the final begin operation behind callbacks.
#[repr(C)]
pub struct ZSTD_rust_compressBeginUsingCDictState {
cctx: *mut c_void,
cdict: *const c_void,
cctx_params: *mut ZSTD_CCtx_params,
cdict_cparams: *const ZSTD_compressionParameters,
cdict_content_size: *const usize,
cdict_compression_level: *const c_int,
f_params: *const ZSTD_frameParameters,
pledged_src_size: *const u64,
exclusion_mask: *const c_uint,
init_params: CompressBeginUsingCDictInitParamsFn,
adjust_window: CompressBeginUsingCDictAdjustWindowFn,
begin: CompressBeginUsingCDictBeginFn,
}
const _: () = {
assert!(offset_of!(ZSTD_rust_compressBeginUsingCDictState, cctx) == 0);
assert!(offset_of!(ZSTD_rust_compressBeginUsingCDictState, cdict) == size_of::<usize>());
assert!(
offset_of!(ZSTD_rust_compressBeginUsingCDictState, cctx_params) == 2 * size_of::<usize>()
);
assert!(
offset_of!(ZSTD_rust_compressBeginUsingCDictState, cdict_cparams) == 3 * size_of::<usize>()
);
assert!(
offset_of!(ZSTD_rust_compressBeginUsingCDictState, cdict_content_size)
== 4 * size_of::<usize>()
);
assert!(
offset_of!(
ZSTD_rust_compressBeginUsingCDictState,
cdict_compression_level
) == 5 * size_of::<usize>()
);
assert!(offset_of!(ZSTD_rust_compressBeginUsingCDictState, f_params) == 6 * size_of::<usize>());
assert!(
offset_of!(ZSTD_rust_compressBeginUsingCDictState, pledged_src_size)
== 7 * size_of::<usize>()
);
assert!(
offset_of!(ZSTD_rust_compressBeginUsingCDictState, exclusion_mask)
== size_of::<[usize; 8]>()
);
assert!(
offset_of!(ZSTD_rust_compressBeginUsingCDictState, init_params) == 9 * size_of::<usize>()
);
assert!(
offset_of!(ZSTD_rust_compressBeginUsingCDictState, adjust_window)
== 10 * size_of::<usize>()
);
assert!(offset_of!(ZSTD_rust_compressBeginUsingCDictState, begin) == 11 * size_of::<usize>());
assert!(size_of::<ZSTD_rust_compressBeginUsingCDictState>() == size_of::<[usize; 12]>());
};
const CDICT_PARAMS_SRC_SIZE_CUTOFF: u64 = 128 * 1024;
const CDICT_PARAMS_DICT_SIZE_MULTIPLIER: u64 = 6;
const CDICT_WINDOW_SOURCE_SIZE_CAP: u64 = 1 << 19;
/// Apply the CDict begin policy while keeping private C state behind callbacks.
#[no_mangle]
pub unsafe extern "C" fn ZSTD_rust_compressBeginUsingCDict(
state: *const ZSTD_rust_compressBeginUsingCDictState,
) -> usize {
if state.is_null() {
return ERROR(ZstdErrorCode::Generic);
}
let state = unsafe { &*state };
if state.cdict.is_null() {
return ERROR(ZstdErrorCode::DictionaryWrong);
}
if state.cctx_params.is_null()
|| state.cdict_cparams.is_null()
|| state.cdict_content_size.is_null()
|| state.cdict_compression_level.is_null()
|| state.f_params.is_null()
|| state.pledged_src_size.is_null()
|| state.exclusion_mask.is_null()
{
return ERROR(ZstdErrorCode::Generic);
}
let cdict_cparams = unsafe { *state.cdict_cparams };
let cdict_content_size = unsafe { *state.cdict_content_size };
let cdict_compression_level = unsafe { *state.cdict_compression_level };
let pledged_src_size = unsafe { *state.pledged_src_size };
let cdict_size_threshold =
(cdict_content_size as u64).wrapping_mul(CDICT_PARAMS_DICT_SIZE_MULTIPLIER);
let cparams = if pledged_src_size < CDICT_PARAMS_SRC_SIZE_CUTOFF
|| pledged_src_size < cdict_size_threshold
|| pledged_src_size == ZSTD_CONTENTSIZE_UNKNOWN
|| cdict_compression_level == 0
{
cdict_cparams
} else {
ZSTD_rust_params_getCParams(
cdict_compression_level,
pledged_src_size,
cdict_content_size,
unsafe { *state.exclusion_mask },
)
};
let params = ZSTD_parameters {
cParams: cparams,
fParams: unsafe { *state.f_params },
};
unsafe {
(state.init_params)(state.cctx_params.cast(), &params, cdict_compression_level);
}
if pledged_src_size != ZSTD_CONTENTSIZE_UNKNOWN {
let limited_src_size = pledged_src_size.min(CDICT_WINDOW_SOURCE_SIZE_CAP) as u32;
let limited_src_log = if limited_src_size > 1 {
ZSTD_highbit32(limited_src_size - 1) + 1
} else {
1
};
unsafe {
(state.adjust_window)(state.cctx_params.cast(), limited_src_log);
}
}
unsafe {
(state.begin)(
state.cctx,
state.cdict,
state.cctx_params.cast_const().cast(),
pledged_src_size,
)
}
}
/// Rust-owned policy for `ZSTD_CCtx_loadDictionary_advanced()`.
#[no_mangle]
pub unsafe extern "C" fn ZSTD_rust_CCtx_loadDictionaryAdvanced(
@@ -743,6 +891,299 @@ mod tests {
assert_eq!(probe.events, [3]);
}
#[derive(Default)]
struct CdictBeginProbe {
events: Vec<&'static str>,
initialized: Option<ZSTD_parameters>,
compression_level: c_int,
min_window_logs: Vec<c_uint>,
begin_result: usize,
}
unsafe fn cdict_begin_probe(context: *mut c_void) -> &'static mut CdictBeginProbe {
unsafe { &mut *context.cast::<CdictBeginProbe>() }
}
unsafe extern "C" fn cdict_begin_init(
context: *mut c_void,
params: *const ZSTD_parameters,
compression_level: c_int,
) {
let probe = unsafe { cdict_begin_probe(context) };
probe.events.push("init");
probe.initialized = Some(unsafe { *params });
probe.compression_level = compression_level;
}
unsafe extern "C" fn cdict_begin_adjust_window(context: *mut c_void, min_window_log: c_uint) {
let probe = unsafe { cdict_begin_probe(context) };
probe.events.push("adjust");
probe.min_window_logs.push(min_window_log);
}
unsafe extern "C" fn cdict_begin_begin(
context: *mut c_void,
_cdict: *const c_void,
_cctx_params: *const c_void,
_pledged_src_size: u64,
) -> usize {
let probe = unsafe { cdict_begin_probe(context) };
probe.events.push("begin");
probe.begin_result
}
fn cdict_begin_test_state(
probe: &mut CdictBeginProbe,
cdict: *const c_void,
cdict_cparams: &ZSTD_compressionParameters,
cdict_content_size: &usize,
cdict_compression_level: &c_int,
f_params: &ZSTD_frameParameters,
pledged_src_size: &u64,
exclusion_mask: &c_uint,
) -> ZSTD_rust_compressBeginUsingCDictState {
ZSTD_rust_compressBeginUsingCDictState {
cctx: (probe as *mut CdictBeginProbe).cast(),
cdict,
cctx_params: (probe as *mut CdictBeginProbe).cast(),
cdict_cparams,
cdict_content_size,
cdict_compression_level,
f_params,
pledged_src_size,
exclusion_mask,
init_params: cdict_begin_init,
adjust_window: cdict_begin_adjust_window,
begin: cdict_begin_begin,
}
}
#[test]
fn cdict_begin_rejects_a_null_dictionary_before_reading_state() {
let state = ZSTD_rust_compressBeginUsingCDictState {
cctx: ptr::null_mut(),
cdict: ptr::null(),
cctx_params: ptr::null_mut(),
cdict_cparams: ptr::null(),
cdict_content_size: ptr::null(),
cdict_compression_level: ptr::null(),
f_params: ptr::null(),
pledged_src_size: ptr::null(),
exclusion_mask: ptr::null(),
init_params: cdict_begin_init,
adjust_window: cdict_begin_adjust_window,
begin: cdict_begin_begin,
};
let result = unsafe { ZSTD_rust_compressBeginUsingCDict(&state) };
assert_eq!(result, ERROR(ZstdErrorCode::DictionaryWrong));
}
#[test]
fn cdict_begin_reuses_cdict_params_below_the_source_cutoff() {
let mut probe = CdictBeginProbe::default();
let cdict_cparams = ZSTD_compressionParameters {
windowLog: 17,
chainLog: 12,
hashLog: 13,
searchLog: 1,
minMatch: 4,
targetLength: 16,
strategy: 3,
};
let cdict_content_size = 1usize;
let cdict_compression_level = 3;
let f_params = ZSTD_frameParameters::default();
let pledged_src_size = CDICT_PARAMS_SRC_SIZE_CUTOFF - 1;
let exclusion_mask = 0;
let state = cdict_begin_test_state(
&mut probe,
ptr::dangling(),
&cdict_cparams,
&cdict_content_size,
&cdict_compression_level,
&f_params,
&pledged_src_size,
&exclusion_mask,
);
let result = unsafe { ZSTD_rust_compressBeginUsingCDict(&state) };
assert_eq!(result, 0);
assert_eq!(probe.events, ["init", "adjust", "begin"]);
assert_eq!(probe.initialized.unwrap().cParams, cdict_cparams);
assert_eq!(probe.compression_level, cdict_compression_level);
assert_eq!(probe.min_window_logs, [17]);
}
#[test]
fn cdict_begin_reuses_cdict_params_for_unknown_source_without_adjustment() {
let mut probe = CdictBeginProbe::default();
let cdict_cparams = ZSTD_compressionParameters {
windowLog: 17,
chainLog: 12,
hashLog: 13,
searchLog: 1,
minMatch: 4,
targetLength: 16,
strategy: 3,
};
let cdict_content_size = 1usize;
let cdict_compression_level = 3;
let f_params = ZSTD_frameParameters::default();
let pledged_src_size = ZSTD_CONTENTSIZE_UNKNOWN;
let exclusion_mask = 0;
let state = cdict_begin_test_state(
&mut probe,
ptr::dangling(),
&cdict_cparams,
&cdict_content_size,
&cdict_compression_level,
&f_params,
&pledged_src_size,
&exclusion_mask,
);
let result = unsafe { ZSTD_rust_compressBeginUsingCDict(&state) };
assert_eq!(result, 0);
assert_eq!(probe.events, ["init", "begin"]);
assert_eq!(probe.initialized.unwrap().cParams, cdict_cparams);
assert!(probe.min_window_logs.is_empty());
}
#[test]
fn cdict_begin_reuses_cdict_params_for_dictionary_ratio_or_zero_level() {
let cdict_cparams = ZSTD_compressionParameters {
windowLog: 10,
chainLog: 6,
hashLog: 6,
searchLog: 1,
minMatch: 3,
targetLength: 0,
strategy: 1,
};
let cdict_content_size = 64 * 1024usize;
let f_params = ZSTD_frameParameters::default();
let exclusion_mask = 0;
let mut ratio_probe = CdictBeginProbe::default();
let ratio_compression_level = 3;
let ratio_pledged_src_size = 256 * 1024;
let ratio_state = cdict_begin_test_state(
&mut ratio_probe,
ptr::dangling(),
&cdict_cparams,
&cdict_content_size,
&ratio_compression_level,
&f_params,
&ratio_pledged_src_size,
&exclusion_mask,
);
let ratio_result = unsafe { ZSTD_rust_compressBeginUsingCDict(&ratio_state) };
assert_eq!(ratio_result, 0);
assert_eq!(ratio_probe.initialized.unwrap().cParams, cdict_cparams);
let mut zero_level_probe = CdictBeginProbe::default();
let zero_level_compression_level = 0;
let zero_level_pledged_src_size = 1 << 20;
let zero_level_state = cdict_begin_test_state(
&mut zero_level_probe,
ptr::dangling(),
&cdict_cparams,
&cdict_content_size,
&zero_level_compression_level,
&f_params,
&zero_level_pledged_src_size,
&exclusion_mask,
);
let zero_level_result = unsafe { ZSTD_rust_compressBeginUsingCDict(&zero_level_state) };
assert_eq!(zero_level_result, 0);
assert_eq!(zero_level_probe.initialized.unwrap().cParams, cdict_cparams);
}
#[test]
fn cdict_begin_selects_public_params_at_the_source_cutoff() {
let mut probe = CdictBeginProbe::default();
let cdict_cparams = ZSTD_compressionParameters {
windowLog: 10,
chainLog: 6,
hashLog: 6,
searchLog: 1,
minMatch: 3,
targetLength: 0,
strategy: 1,
};
let cdict_content_size = 1usize;
let cdict_compression_level = 3;
let f_params = ZSTD_frameParameters::default();
let pledged_src_size = CDICT_PARAMS_SRC_SIZE_CUTOFF;
let exclusion_mask = 0;
let state = cdict_begin_test_state(
&mut probe,
ptr::dangling(),
&cdict_cparams,
&cdict_content_size,
&cdict_compression_level,
&f_params,
&pledged_src_size,
&exclusion_mask,
);
let expected_cparams = ZSTD_rust_params_getCParams(
cdict_compression_level,
pledged_src_size,
cdict_content_size,
exclusion_mask,
);
let result = unsafe { ZSTD_rust_compressBeginUsingCDict(&state) };
assert_eq!(result, 0);
assert_eq!(probe.initialized.unwrap().cParams, expected_cparams);
assert_eq!(probe.events, ["init", "adjust", "begin"]);
}
#[test]
fn cdict_begin_preserves_order_and_begin_errors_for_large_sources() {
let mut probe = CdictBeginProbe {
begin_result: ERROR(ZstdErrorCode::DstSizeTooSmall),
..Default::default()
};
let cdict_cparams = ZSTD_compressionParameters {
windowLog: 10,
chainLog: 6,
hashLog: 6,
searchLog: 1,
minMatch: 3,
targetLength: 0,
strategy: 1,
};
let cdict_content_size = 1usize;
let cdict_compression_level = 3;
let f_params = ZSTD_frameParameters::default();
let pledged_src_size = 1 << 20;
let exclusion_mask = 0;
let state = cdict_begin_test_state(
&mut probe,
ptr::dangling(),
&cdict_cparams,
&cdict_content_size,
&cdict_compression_level,
&f_params,
&pledged_src_size,
&exclusion_mask,
);
let result = unsafe { ZSTD_rust_compressBeginUsingCDict(&state) };
assert_eq!(result, probe.begin_result);
assert_eq!(probe.events, ["init", "adjust", "begin"]);
assert_eq!(probe.min_window_logs, [19]);
}
fn assert_dictionary_corrupted(result: usize) {
assert!(ERR_isError(result));
assert_eq!(