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+# Pre13 H03a: bounded qstr comparator carrier
+
+## Scope
+
+- Added a private `struct erofs_qstr` to `src/namei.c` with explicit `name`
+  and `end` pointers.
+- Converted `erofs_dirnamecmp()` to consume bounded qstr objects.
+- Kept the existing search helpers on their original pointer/length interface
+  through a temporary local adapter.  Block search, VOP lookup, vnode locking,
+  namecache timing, errno handling, readdir, and cookies are unchanged.
+
+## Static equivalence
+
+- Search and disk lengths are still derived from the same pointer ranges.
+- `matched` is clamped to both ranges before comparison.
+- Comparison remains unsigned byte ordering, supports non-NUL search keys and
+  embedded NUL bytes, and never assumes a trailing NUL at the disk boundary.
+- The adapter performs no allocation, copying, normalization, or error mapping.
+
+## Comparator gate
+
+Tests baseline: `ce03c283e6e2cb8f1b69c8eff21f7d06098a4fbe`.
+
+- Python deterministic corpus: PASS, 11,562 cases.
+- Independent C harness: PASS, 1,048,576 cases.
+
+These host comparator results prove the old and new comparison contracts are
+equivalent for the generated corpus.  They are not dynamic filesystem feature
+test results.  H03 still requires TC042, TC043, TC044, TC045, TC053, TC054,
+TC123, TC141, and TC148, followed by the final smoke test.