The overflow-correction policy and scalar correction arithmetic were already
Rust-owned, but the stateful window rebase still lived in the C
ZSTD_window_correctOverflow() inline. That left pointer advancement, limit
clamping, and the correction counter as an untracked production C algorithm
on every compression path that protects matchfinder indices.
Replace that inline with a five-pointer projection. C continues to compute the
private source index and choose the correction context, while Rust now owns
the rebasing transition: it advances the regular and dictionary bases, clamps
both limits with the original wrapping U32 behavior, checks the correction
invariants in debug builds, and increments the overflow-correction counter.
The C/Rust projection has explicit layout assertions, and the Rust fixture
covers the pointer, limit, and counter updates together.
Test Plan:
- ulimit -v 41943040; CARGO_BUILD_JOBS=1 cargo check --manifest-path rust/Cargo.toml --tests
- ulimit -v 41943040; CARGO_BUILD_JOBS=1 cargo clippy --manifest-path rust/cli/Cargo.toml --all-targets -- -D warnings
- ulimit -v 41943040; CARGO_BUILD_JOBS=1 make -j1
- ulimit -v 41943040; CARGO_BUILD_JOBS=1 make -j1 -C tests invalidDictionaries
- ulimit -v 41943040; make -j1 -C tests test
- git diff --check
ddidderr
8aa7156943