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
and only defines a sub-block boundary when
it believes that it is compressible.
It's effectively an optimization,
avoiding a compression cycle to reach the same conclusion.
note that the size of individual compressed blocks will vary more wildly with this modification.
But it seems good enough for a first test, and fix the speed regression issue.
Further refinements can be attempted later.
and in `decodecorpus`:
the specific case `nbSeq=127` can be represented using the 1-byte format.
Note that both the 1-byte and the 2-bytes formats are valid to represent this case,
so there was no "error", produced data remains valid,
it's just that the 1-byte format is more efficient.
fix#3667
Credit to @ip7z for finding this issue.
```
for f in $(find . \( -path ./.git -o -path ./tests/fuzz/corpora \) -prune -o -type f);
do
sed -i 's/Facebook, Inc\./Meta Platforms, Inc. and affiliates./' $f;
done
```
the new contracts seems to make more sense :
updateRep() updates an array of repeat offsets _in place_,
while newRep() generates a new structure with the updated repeat-offset array.
Most callers are actually expecting the in-place variant,
and a limited sub-section, in `zstd_opt.c` mainly, prefer `newRep()`.
This saves some 1.7Kb in rodata section (x86_64, zstd tool),
while assembler code stays the same except
the type of a few load/extend instructions.
Should not have negative performance implications.
* Switch to yearless copyright per FB policy
* Fix up SPDX-License-Identifier lines in `contrib/linux-kernel` sources
* Add zstd copyright/license header to the `contrib/linux-kernel` sources
* Update the `tests/test-license.py` to check for yearless copyright
* Improvements to `tests/test-license.py`
* Check `contrib/linux-kernel` in `tests/test-license.py`
The bound check condition should always be met because we selected `set_basic` as
our encoding type. But that code is very far away, so assert it is true so if it is
ever false we can catch it, and add a bounds check.
Fixes#2213.
ddidderr
Yann Collet