Export of internal Abseil changes

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790f9061df340cd900e8da70e66c363f7af3c2eb by Abseil Team <absl-team@google.com>:

Add support for rvalue reference to function types.

PiperOrigin-RevId: 324508531

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51fe201dbb41a3ebc3d49ff65250b5f464279d43 by Abseil Team <absl-team@google.com>:

Cleaning up function comment style; no substantive change.

PiperOrigin-RevId: 324497401

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da8595d5266577d0c170528d12f6de17b8affcc2 by Abseil Team <absl-team@google.com>:

Add support for demangling GNU vector types.

PiperOrigin-RevId: 324494559

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0cb0acf88c1750f6963c9cb85249f9b4f0bd5104 by Abseil Team <absl-team@google.com>:

Add support for thread-local types.

PiperOrigin-RevId: 324491183

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c676bc8380560599cd26f7f231e04e6be532e904 by Abseil Team <absl-team@google.com>:

Add support for demangling "Du" (char8_t).

PiperOrigin-RevId: 324441607

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b218bf6467bc62b327214782c881e8224ad91509 by Abseil Team <absl-team@google.com>:

Update doc comments in header of `any.h` to reflect that `absl::variant` has been released.

PiperOrigin-RevId: 324431690

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e5b579f3f1aa598c1f62e71dba7103b98811de59 by Laramie Leavitt <lar@google.com>:

Bugfix: Fix bounds in absl::Uniform where one of the bounds is min/max.

When absl::Uniform(rng, tag, a, b) is called, the tag is used in conjunction with the type to determine whether or not to manipulate the bounds to make them inclusive or exclusive through the uniform_*_bound functions. Unfortunately, at limits of the interval the function was not well behaved.

The previous implementation used wrapping arithmetic. This causes incorrect bounds computation at the extremes (numeric_limits::min / numeric_limits::max) the bound would wrap.

Improve this situation by:

1/ Changing the uniform_*_bound functions to use saturating arithmetic instead of wrapping, thus in the unsigned case, the upper_bound of IntervalOpenOpen for 0 is now 0, rather than numeric_limits::max, likewise for the lower bound.

2/ Adjusting the hi/lo checks in the distributions. When the interval is empty, such as for absl::Uniform(absl::IntervalOpenOpen, gen, 1, 0), the return value is somewhat nonsensical. Now absl::Uniform more consistently returns the low input rather than any adjusted input. In the above case, that means that 1 is returned rather than 2.

NOTE: Calls to absl::Uniform where the resolved upper bound is < the lower bound  are still ill-formed and should be avoided.

3/ Adding better tests.

The underlying uniform_*_distribution classes are not affected.

PiperOrigin-RevId: 324240873
GitOrigin-RevId: 790f9061df340cd900e8da70e66c363f7af3c2eb
Change-Id: I2a2208650ea3135c575e200b868ce1d275069fc8
9 files changed
tree: 0b1e861b0d2c16f78d0f2e861a94a2bccf38965a
  1. absl/
  2. ci/
  3. CMake/
  4. .clang-format
  5. .gitignore
  6. ABSEIL_ISSUE_TEMPLATE.md
  7. AUTHORS
  8. BUILD.bazel
  9. CMakeLists.txt
  10. conanfile.py
  11. CONTRIBUTING.md
  12. FAQ.md
  13. LICENSE
  14. LTS.md
  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 is the official build system for Abseil, which is supported on most major platforms (Linux, Windows, macOS, for example) and compilers. 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.

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.
  • 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.
  • 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.

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: