The public CCtx and CStream size-estimation APIs still selected row-matchfinder modes and walked compression levels in C, leaving a policy-level implementation behind the Rust workspace-sizing bridge. That also made the C layer responsible for the subtle raw-size_t MAX behavior used when an estimator returns an encoded error.
Move the row-mode selection and shared monotonic memory-budget policy into Rust. Keep the C callbacks responsible for constructing private ZSTD_CCtx_params values and for the distinct CCtx/CStream sizing formulas, so no private parameter layout crosses the ABI. Preserve the signed MIN(compressionLevel, 1) start and raw maxima exactly.
Test Plan:
- cargo +nightly fmt --manifest-path rust/Cargo.toml --all -- --check
- git diff --check
- ulimit -v 41943040; CARGO_BUILD_JOBS=1 make -j1
ddidderr
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