Export of internal Abseil changes

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4ff721439234e91caf6f7b772e5f554e7dd423c8 by Benjamin Barenblat <bbaren@google.com>:

Remove endian-sensitivity from hash slow path

Prior to this commit, the Abseil hash fast path was endian-agnostic, but
the slow path assumed a little-endian platform. Change the slow path to
be endian-correct, ensuring that values produced by the fast and slow
paths are equal even on big-endian systems.

PiperOrigin-RevId: 355424258

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7f4fe1aa4de46ad0a2ef19fa9c061fc12a7391ed by Abseil Team <absl-team@google.com>:

Directly store CordzInfo in the InlineData data contents of InlineRep

This greatly reduces the cost of coping and moving cords. Especially the move constructor and move assignment are now back to lean loads and stores without needing any CordzInfo lookups for tracked cords.

PiperOrigin-RevId: 355409161

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3ca4ca84ed6d98f1e383ffd8d12c28876e905bb3 by Abseil Team <absl-team@google.com>:

Add #include <unordered_map>

PiperOrigin-RevId: 355386114

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30b0ffad0621971b3135148fcc9e183b0dd2a6bb by Abseil Team <absl-team@google.com>:

Optimize Cord copy constructor

This change avoids double stores of the Cord copy constructor from the zero init of the InlineData / InlineRep contents followed by the assignment and inlines the copy constructor.

PiperOrigin-RevId: 355287939

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0c043fa7b6e41ca7cefc5edc1e17ad46223e4e77 by CJ Johnson <johnsoncj@google.com>:

Now that the absl::Cleanup example returns absl::Status, since we decided on absl::FailedPreconditionError, the precondition should be a positive statement and then the check should be failure to adhere to that positive statement

PiperOrigin-RevId: 355216923

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9ed922ca5d28fe8790ec6bc0837cf39fbcc92896 by Gennadiy Rozental <rogeeff@google.com>:

Do not set mvsc linker flags for clang-cl (fixes #874)

Import of https://github.com/abseil/abseil-cpp/pull/891

PiperOrigin-RevId: 355199380
GitOrigin-RevId: 4ff721439234e91caf6f7b772e5f554e7dd423c8
Change-Id: I3d9d2383549720d7a91f9108dfcd979ad6632fce
10 files changed
tree: 35e1acfc8db537ac89598c2d5c4590693a91de45
  1. .github/
  2. absl/
  3. ci/
  4. CMake/
  5. .clang-format
  6. .gitignore
  7. ABSEIL_ISSUE_TEMPLATE.md
  8. AUTHORS
  9. BUILD.bazel
  10. CMakeLists.txt
  11. conanfile.py
  12. CONTRIBUTING.md
  13. FAQ.md
  14. LICENSE
  15. README.md
  16. UPGRADES.md
  17. WORKSPACE
README.md

Abseil - C++ Common Libraries

The repository contains the Abseil C++ library code. Abseil is an open-source collection of C++ code (compliant to C++11) designed to augment the C++ standard library.

Table of Contents

About Abseil

Abseil is an open-source collection of C++ library code designed to augment the C++ standard library. The Abseil library code is collected from Google's own C++ code base, has been extensively tested and used in production, and is the same code we depend on in our daily coding lives.

In some cases, Abseil provides pieces missing from the C++ standard; in others, Abseil provides alternatives to the standard for special needs we've found through usage in the Google code base. We denote those cases clearly within the library code we provide you.

Abseil is not meant to be a competitor to the standard library; we've just found that many of these utilities serve a purpose within our code base, and we now want to provide those resources to the C++ community as a whole.

Quickstart

If you want to just get started, make sure you at least run through the Abseil Quickstart. The Quickstart contains information about setting up your development environment, downloading the Abseil code, running tests, and getting a simple binary working.

Building Abseil

Bazel and CMake are the official build systems for Abseil.

See the quickstart for more information on building Abseil using the Bazel build system.

If you require CMake support, please check the CMake build instructions and CMake Quickstart.

Support

Abseil is officially supported on many platforms. See the Abseil platform support guide for details on supported operating systems, compilers, CPUs, etc.

Codemap

Abseil contains the following C++ library components:

  • base Abseil Fundamentals
    The base library contains initialization code and other code which all other Abseil code depends on. Code within base may not depend on any other code (other than the C++ standard library).
  • algorithm
    The algorithm library contains additions to the C++ <algorithm> library and container-based versions of such algorithms.
  • cleanup
    The cleanup library contains the control-flow-construct-like type absl::Cleanup which is used for executing a callback on scope exit.
  • container
    The container library contains additional STL-style containers, including Abseil's unordered “Swiss table” containers.
  • debugging
    The debugging library contains code useful for enabling leak checks, and stacktrace and symbolization utilities.
  • hash
    The hash library contains the hashing framework and default hash functor implementations for hashable types in Abseil.
  • memory
    The memory library contains C++11-compatible versions of std::make_unique() and related memory management facilities.
  • meta
    The meta library contains C++11-compatible versions of type checks available within C++14 and C++17 versions of the C++ <type_traits> library.
  • numeric
    The numeric library contains C++11-compatible 128-bit integers.
  • status
    The status contains abstractions for error handling, specifically absl::Status and absl::StatusOr<T>.
  • strings
    The strings library contains a variety of strings routines and utilities, including a C++11-compatible version of the C++17 std::string_view type.
  • synchronization
    The synchronization library contains concurrency primitives (Abseil's absl::Mutex class, an alternative to std::mutex) and a variety of synchronization abstractions.
  • time
    The time library contains abstractions for computing with absolute points in time, durations of time, and formatting and parsing time within time zones.
  • types
    The types library contains non-container utility types, like a C++11-compatible version of the C++17 std::optional type.
  • utility
    The utility library contains utility and helper code.

Releases

Abseil recommends users “live-at-head” (update to the latest commit from the master branch as often as possible). However, we realize this philosophy doesn't work for every project, so we also provide Long Term Support Releases to which we backport fixes for severe bugs. See our release management document for more details.

License

The Abseil C++ library is licensed under the terms of the Apache license. See LICENSE for more information.

Links

For more information about Abseil: