Share the type-erased resize implementation between full SOO tables and allocated tables to reduce binary size. `ResizeFullSooTable` (with `InsertOldSooSlotAndInitializeControlBytes`) and `ResizeAllocatedTableWithSeedChange` (with `FindNewPositionsAndTransferSlots`) performed the same sequence of operations: allocate a new backing array, generate a new seed, reset the control bytes, transfer the elements to their new positions, release the old storage, reset the growth left, and report the resize to hashtablez. The only differences were where the old elements live (the SOO slot inside `CommonFields` vs. the old backing array) and how the infoz is obtained (forced sampling vs. kept from the allocated table). Merge them into a single out-of-line `ResizeTableWithSeedChangeImpl` that handles both cases. `FindNewPositionsAndTransferSlots` now receives the new control bytes and slots explicitly instead of reading them from `CommonFields`, so the control pointer is stored only after the transfer and the SOO slot is not overwritten. All of these paths are cold (reserving or rehashing a non-empty table, or forcing a sample of a full SOO table), so sharing the code does not affect hot paths. `ReserveAllocatedTable` and `Rehash` no longer need to dispatch between the SOO and the allocated case. The type-erased code in `raw_hash_set.cc` shrinks by 1,047 bytes (-5.0%) in optimized builds. It is also good simplification. PiperOrigin-RevId: 1002592266
The repository contains the Abseil C++ library code. Abseil is an open-source collection of C++ code (compliant to C++17) designed to augment the C++ standard library.
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.
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.
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.
Abseil follows Google's Foundational C++ Support Policy. See this table for a list of currently supported versions compilers, platforms, and build tools.
Abseil contains the following C++ library components:
base 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 algorithm library contains additions to the C++ <algorithm> library and container-based versions of such algorithms.cleanup cleanup library contains the control-flow-construct-like type absl::Cleanup which is used for executing a callback on scope exit.container container library contains additional STL-style containers, including Abseil's unordered “Swiss table” containers.crc The crc library contains code for computing error-detecting cyclic redundancy checks on data.debugging debugging library contains code useful for enabling leak checks, and stacktrace and symbolization utilities.flags flags library contains code for handling command line flags for libraries and binaries built with Abseil.hash hash library contains the hashing framework and default hash functor implementations for hashable types in Abseil.log log library contains LOG and CHECK macros and facilities for writing logged messages out to disk, stderr, or user-extensible destinations.memory memory library contains memory management facilities that augment C++'s <memory> library.meta meta library contains type checks similar to those available in the C++ <type_traits> library.numeric numeric library contains 128-bit integer types as well as implementations of C++20's bitwise math functions.profiling profiling library contains utility code for profiling C++ entities. It is currently a private dependency of other Abseil libraries.random random library contains functions for generating pseudorandom values.status status library contains abstractions for error handling, specifically absl::Status and absl::StatusOr<T>.strings strings library contains a variety of strings routines and utilities.synchronization synchronization library contains concurrency primitives (Abseil's absl::Mutex class, an alternative to std::mutex) and a variety of synchronization abstractions.time time library contains abstractions for computing with absolute points in time, durations of time, and formatting and parsing time within time zones.types types library contains non-container utility types.utility utility library contains utility and helper code.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.
The Abseil C++ library is licensed under the terms of the Apache license. See LICENSE for more information.
For more information about Abseil: