sumdb/dirhash: directory tree hash algorithm

Copied from cmd/go/internal/dirhash, with additional doc comments.

For golang/go#31761.

Change-Id: Id56c1bbb6f27e69194f383d49b9def6876f948be
Reviewed-on: https://go-review.googlesource.com/c/mod/+/176464
Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>
2 files changed
tree: 6683325617794b728a685f6cb21606744ced3c66
  1. LICENSE
  2. PATENTS
  3. README
  4. codereview.cfg
  5. go.mod
  6. go.sum
  7. module/
  8. semver/
  9. sumdb/