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flutter / third_party / protobuf / 896e74c141b00ad1034355e53effac311b0d5a26
commit896e74c141b00ad1034355e53effac311b0d5a26[log] [tgz]
authorJoshua Haberman <haberman@google.com>Fri Sep 09 08:34:53 2022 -0700
committerCopybara-Service <copybara-worker@google.com>Fri Sep 09 08:35:31 2022 -0700
treeda3e2ef188093e6644b2bd446b825802a11ad8f1
parent5ae398f2021a75c4f2adf4e267431d64b1e229a1 [diff]
Optimizes `upb_MiniTable_Enum` for large but dense enums.

Optimizes `upb_MiniTable_Enum` for enums with many values (>64) but with relatively dense packing in numeric space.

This CL optimizes both the size and speed of such enums:

- size: 30x code size reduction
- speed: moved from linear search to a constant-time bit test

Negative enum values are still expensive, as they are never put into the bitfield.

PiperOrigin-RevId: 473259819
7 files changed
tree: da3e2ef188093e6644b2bd446b825802a11ad8f1
  1. .bazelci/
  2. .github/
  3. bazel/
  4. benchmarks/
  5. cmake/
  6. docs/
  7. python/
  8. third_party/
  9. upb/
  10. upbc/
  11. .bazelignore
  12. .bazelrc
  13. .clang-format
  14. .gitignore
  15. BUILD
  16. CONTRIBUTING.md
  17. DESIGN.md
  18. LICENSE
  19. README.md
  20. WORKSPACE
README.md

μpb: small, fast C protos

μpb (often written ‘upb’) is a small protobuf implementation written in C.

upb is the core runtime for protobuf languages extensions in Ruby, PHP, and (soon) Python.

While upb offers a C API, the C API & ABI are not stable. For this reason, upb is not generally offered as a C library for direct consumption, and there are no releases.

Features

upb has comparable speed to protobuf C++, but is an order of magnitude smaller in code size.

Like the main protobuf implementation in C++, it supports:

  • a generated API (in C)
  • reflection
  • binary & JSON wire formats
  • text format serialization
  • all standard features of protobufs (oneofs, maps, unknown fields, extensions, etc.)
  • full conformance with the protobuf conformance tests

upb also supports some features that C++ does not:

  • optional reflection: generated messages are agnostic to whether reflection will be linked in or not.
  • no global state: no pre-main registration or other global state.
  • fast reflection-based parsing: messages loaded at runtime parse just as fast as compiled-in messages.

However there are a few features it does not support:

  • text format parsing
  • deep descriptor verification: upb's descriptor validation is not as exhaustive as protoc.

Install

For Ruby, use RubyGems:

$ gem install google-protobuf

For PHP, use PECL:

$ sudo pecl install protobuf

Alternatively, you can build and install upb using vcpkg dependency manager:

git clone https://github.com/Microsoft/vcpkg.git
cd vcpkg
./bootstrap-vcpkg.sh
./vcpkg integrate install
./vcpkg install upb

The upb port in vcpkg is kept up to date by microsoft team members and community contributors.

If the version is out of date, please create an issue or pull request on the vcpkg repository.

Contributing

Please see CONTRIBUTING.md.