removed overzealous inlines

(possible performance impact)

.appveyor.yml

@@ -1,4 +1,6 @@
-# Copyright 2017 Daniel James
+# Copyright 2016, 2017 Peter Dimov
+# Copyright 2017 - 2019 James E. King III
+# Copyright 2019 - 2021 Alexander Grund
 # Distributed under the Boost Software License, Version 1.0.
 # (See accompanying file LICENSE_1_0.txt or copy at http://boost.org/LICENSE_1_0.txt)
 
@@ -10,48 +12,138 @@ branches:
   only:
     - master
     - develop
+    - /bugfix\/.*/
     - /feature\/.*/
+    - /fix\/.*/
+    - /pr\/.*/
+
+matrix:
+  fast_finish: false
+  # Adding MAYFAIL to any matrix job allows it to fail but the build stays green:
+  allow_failures:
+    - MAYFAIL: true
 
 environment:
+  global:
+    B2_CI_VERSION: 1
+    GIT_FETCH_JOBS: 4
+    B2_ADDRESS_MODEL: 32,64
+    B2_VARIANT: debug,release
+
   matrix:
-    - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2015
-      TOOLSET: msvc-9.0,msvc-10.0,msvc-11.0
-      ADDRMD: 32
-    - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2015
-      TOOLSET: msvc-12.0,msvc-14.0
-      ADDRMD: 32,64
-    - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2017
-      TOOLSET: msvc-14.1
-      CXXSTD: 14,17
-      ADDRMD: 32,64
-    - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2019
-      TOOLSET: clang-win
-      CXXSTD: 14
-      ADDRMD: 32,64
-    - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2019
-      TOOLSET: clang-win
-      CXXSTD: 17
-      ADDRMD: 32,64
-    - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2019
-      TOOLSET: clang-win
-      CXXSTD: latest
-      ADDRMD: 32,64
+    - FLAVOR: Visual Studio 2008, 2010, 2012
+      APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2015
+      B2_TOOLSET: msvc-9.0,msvc-10.0,msvc-11.0
+      B2_ADDRESS_MODEL: 32 # No 64bit support
+
+    - FLAVOR: Visual Studio 2013, 2015
+      APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2015
+      B2_TOOLSET: msvc-12.0,msvc-14.0
+
+    - FLAVOR: Visual Studio 2017
+      APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2017
+      B2_CXXSTD: 14,17
+      B2_TOOLSET: msvc-14.1
+
+    - FLAVOR: Visual Studio 2017
+      APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2017
+      B2_CXXSTD: latest
+      B2_TOOLSET: msvc-14.1
+
+    - FLAVOR: cygwin (32-bit)
+      APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2017
+      ADDPATH: C:\cygwin\bin;
+      B2_ADDRESS_MODEL: 32
+      B2_CXXSTD: 03,11,14,1z
+      B2_TOOLSET: gcc
+
+    - FLAVOR: cygwin (64-bit)
+      APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2017
+      ADDPATH: C:\cygwin64\bin;
+      B2_ADDRESS_MODEL: 64
+      B2_CXXSTD: 03,11,14,1z
+      B2_TOOLSET: gcc
+
+    - FLAVOR: cygwin (64-bit, latest)
+      APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2022
+      ADDPATH: C:\cygwin64\bin;
+      B2_ADDRESS_MODEL: 64
+      B2_CXXSTD: 03
+      B2_TOOLSET: gcc
+      B2_FLAGS: "include=libs/unordered/test/unordered include=libs/unordered/test/exception"
+
+    - FLAVOR: cygwin (64-bit, latest)
+      APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2022
+      ADDPATH: C:\cygwin64\bin;
+      B2_ADDRESS_MODEL: 64
+      B2_CXXSTD: 11
+      B2_TOOLSET: gcc
+      B2_FLAGS: "include=libs/unordered/test/unordered include=libs/unordered/test/exception"
+
+    - FLAVOR: cygwin (64-bit, latest)
+      APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2022
+      ADDPATH: C:\cygwin64\bin;
+      B2_ADDRESS_MODEL: 64
+      B2_CXXSTD: 14
+      B2_TOOLSET: gcc
+      B2_FLAGS: "include=libs/unordered/test/unordered include=libs/unordered/test/exception"
+
+    - FLAVOR: cygwin (64-bit, latest)
+      APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2022
+      ADDPATH: C:\cygwin64\bin;
+      B2_ADDRESS_MODEL: 64
+      B2_CXXSTD: 1z
+      B2_TOOLSET: gcc
+      B2_FLAGS: "include=libs/unordered/test/unordered include=libs/unordered/test/exception"
+
+    - FLAVOR: mingw-w64, 32 bit
+      APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2019
+      ADDPATH: C:\mingw-w64\i686-8.1.0-posix-dwarf-rt_v6-rev0\mingw32\bin;
+      B2_CXXSTD: 03,11,14
+      B2_TOOLSET: gcc
+      B2_ADDRESS_MODEL: 32
+
+    - FLAVOR: mingw-w64, 32 bit
+      APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2019
+      ADDPATH: C:\mingw-w64\i686-8.1.0-posix-dwarf-rt_v6-rev0\mingw32\bin;
+      B2_CXXSTD: 17,2a
+      B2_TOOLSET: gcc
+      B2_ADDRESS_MODEL: 32
+
+    - FLAVOR: mingw-w64, 64 bit
+      APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2019
+      ADDPATH: C:\mingw-w64\x86_64-8.1.0-posix-seh-rt_v6-rev0\mingw64\bin;
+      B2_CXXSTD: 03,11,14
+      B2_TOOLSET: gcc
+      B2_ADDRESS_MODEL: 64
+
+    - FLAVOR: mingw-w64, 64 bit
+      APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2019
+      ADDPATH: C:\mingw-w64\x86_64-8.1.0-posix-seh-rt_v6-rev0\mingw64\bin;
+      B2_CXXSTD: 17,2a
+      B2_TOOLSET: gcc
+      B2_ADDRESS_MODEL: 64
+
+    #- FLAVOR: CodeCov (VS 2019)
+    #  APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2019
+    #  B2_CXXFLAGS: -permissive-
+    #  B2_CXXSTD: 14
+    #  B2_TOOLSET: msvc-14.2
+    #  COVERAGE: true
 
 install:
-  - set BOOST_BRANCH=develop
-  - if "%APPVEYOR_REPO_BRANCH%" == "master" set BOOST_BRANCH=master
-  - cd ..
-  - git clone -b %BOOST_BRANCH% --depth 1 https://github.com/boostorg/boost.git boost-root
-  - cd boost-root
-  - git submodule update --init tools/boostdep
-  - xcopy /s /e /q %APPVEYOR_BUILD_FOLDER% libs\unordered\
-  - python tools/boostdep/depinst/depinst.py unordered
-  - cmd /c bootstrap
-  - b2 -d0 headers
+  - git clone --depth 1 https://github.com/boostorg/boost-ci.git C:\boost-ci-cloned
+  # Copy ci folder if not testing Boost.CI
+  - if NOT "%APPVEYOR_PROJECT_NAME%" == "boost-ci" xcopy /s /e /q /i /y C:\boost-ci-cloned\ci .\ci
+  - rmdir /s /q C:\boost-ci-cloned
+  - ci\appveyor\install.bat
 
 build: off
 
-test_script:
-  - if not "%CXXSTD%" == "" set CXXSTD=cxxstd=%CXXSTD%
-  - if not "%ADDRMD%" == "" set ADDRMD=address-model=%ADDRMD%
-  - b2 -j3 libs/unordered/test toolset=%TOOLSET% %CXXSTD% %ADDRMD% variant=debug,release embed-manifest-via=linker
+test_script: ci\build.bat
+
+for:
+  # CodeCov coverage build
+  - matrix:
+      only: [COVERAGE: true]
+    test_script: [ps: ci\codecov.ps1]

.codecov.yml

@@ -0,0 +1,23 @@
+# Copyright 2019 - 2021 Alexander Grund
+# Distributed under the Boost Software License, Version 1.0.
+# (See accompanying file LICENSE_1_0.txt or copy at http://boost.org/LICENSE_1_0.txt)
+#
+# Sample codecov configuration file. Edit as required
+
+codecov:
+  max_report_age: off
+  require_ci_to_pass: yes
+  notify:
+    # Increase this if you have multiple coverage collection jobs
+    after_n_builds: 1
+    wait_for_ci: yes
+
+# Change how pull request comments look
+comment:
+  layout: "reach,diff,flags,files,footer"
+
+# Ignore specific files or folders. Glob patterns are supported.
+# See https://docs.codecov.com/docs/ignoring-paths
+ignore:
+  - extra/**/*
+  # - test/**/*

.drone.jsonnet

@@ -0,0 +1,184 @@
+# Copyright 2022 Peter Dimov
+# Distributed under the Boost Software License, Version 1.0.
+# https://www.boost.org/LICENSE_1_0.txt
+
+local library = "unordered";
+
+local triggers =
+{
+    branch: [ "master", "develop", "feature/*", "bugfix/*" ]
+};
+
+local ubsan = { UBSAN: '1', UBSAN_OPTIONS: 'print_stacktrace=1' };
+local asan = { ASAN: '1' };
+
+local linux_pipeline(name, image, environment, packages = "", sources = [], arch = "amd64") =
+{
+    name: name,
+    kind: "pipeline",
+    type: "docker",
+    trigger: triggers,
+    platform:
+    {
+        os: "linux",
+        arch: arch
+    },
+    steps:
+    [
+        {
+            name: "everything",
+            image: image,
+            environment: environment,
+            commands:
+            [
+                'set -e',
+                'uname -a',
+                'wget -O - https://apt.llvm.org/llvm-snapshot.gpg.key | apt-key add -',
+            ] +
+            (if sources != [] then [ ('apt-add-repository "' + source + '"') for source in sources ] else []) +
+            (if packages != "" then [ 'apt-get update', 'apt-get -y install ' + packages ] else []) +
+            [
+                'export LIBRARY=' + library,
+                './.drone/drone.sh',
+            ]
+        }
+    ]
+};
+
+local macos_pipeline(name, environment, xcode_version = "12.2", osx_version = "catalina", arch = "amd64") =
+{
+    name: name,
+    kind: "pipeline",
+    type: "exec",
+    trigger: triggers,
+    platform: {
+        "os": "darwin",
+        "arch": arch
+    },
+    node: {
+        "os": osx_version
+    },
+    steps: [
+        {
+            name: "everything",
+            environment: environment + { "DEVELOPER_DIR": "/Applications/Xcode-" + xcode_version + ".app/Contents/Developer" },
+            commands:
+            [
+                'uname -a',
+                'export LIBRARY=' + library,
+                './.drone/drone.sh',
+            ]
+        }
+    ]
+};
+
+local windows_pipeline(name, image, environment, arch = "amd64") =
+{
+    name: name,
+    kind: "pipeline",
+    type: "docker",
+    trigger: triggers,
+    platform:
+    {
+        os: "windows",
+        arch: arch
+    },
+    "steps":
+    [
+        {
+            name: "everything",
+            image: image,
+            environment: environment,
+            commands:
+            [
+                'echo $env:DRONE_STAGE_MACHINE',
+                'cmd /C .drone\\\\drone.bat ' + library,
+            ]
+        }
+    ]
+};
+
+[
+    linux_pipeline(
+        "Linux 14.04 GCC 4.4 32/64",
+        "cppalliance/droneubuntu1404:1",
+        { TOOLSET: 'gcc', COMPILER: 'g++-4.4', CXXSTD: '98,0x', ADDRMD: '32,64' },
+        "g++-4.4-multilib",
+        [ "ppa:ubuntu-toolchain-r/test" ],
+    ),
+
+    linux_pipeline(
+        "Linux 14.04 GCC 4.6 32/64",
+        "cppalliance/droneubuntu1404:1",
+        { TOOLSET: 'gcc', COMPILER: 'g++-4.6', CXXSTD: '98,0x', ADDRMD: '32,64' },
+        "g++-4.6-multilib",
+        [ "ppa:ubuntu-toolchain-r/test" ],
+    ),
+
+    linux_pipeline(
+        "Linux 14.04 GCC 4.7 32/64",
+        "cppalliance/droneubuntu1404:1",
+        { TOOLSET: 'gcc', COMPILER: 'g++-4.7', CXXSTD: '98,0x', ADDRMD: '32,64' },
+        "g++-4.7-multilib",
+        [ "ppa:ubuntu-toolchain-r/test" ],
+    ),
+
+    linux_pipeline(
+        "Linux 14.04 GCC 4.8* 32/64",
+        "cppalliance/droneubuntu1404:1",
+        { TOOLSET: 'gcc', COMPILER: 'g++', CXXSTD: '03,11', ADDRMD: '32,64' },
+    ),
+
+    linux_pipeline(
+        "Linux 14.04 GCC 4.9 32/64",
+        "cppalliance/droneubuntu1404:1",
+        { TOOLSET: 'gcc', COMPILER: 'g++-4.9', CXXSTD: '03,11', ADDRMD: '32,64' },
+        "g++-4.9-multilib",
+        [ "ppa:ubuntu-toolchain-r/test" ],
+    ),
+
+    linux_pipeline(
+        "Linux 20.04 GCC 9* ARM64 32",
+        "cppalliance/droneubuntu2004:multiarch",
+        { TOOLSET: 'gcc', COMPILER: 'g++', CXXSTD: '03,11,14,17,2a', ADDRMD: '32' },
+        arch="arm64",
+    ),
+
+    linux_pipeline(
+        "Linux 20.04 GCC 9* ARM64 64",
+        "cppalliance/droneubuntu2004:multiarch",
+        { TOOLSET: 'gcc', COMPILER: 'g++', CXXSTD: '03,11,14,17,2a', ADDRMD: '64' },
+        arch="arm64",
+    ),
+
+    linux_pipeline(
+        "Linux 20.04 GCC 9* S390x 32",
+        "cppalliance/droneubuntu2004:multiarch",
+        { TOOLSET: 'gcc', COMPILER: 'g++', CXXSTD: '03,11,14,17,2a', ADDRMD: '32' },
+        arch="s390x",
+    ),
+
+    linux_pipeline(
+        "Linux 20.04 GCC 9* S390x 64",
+        "cppalliance/droneubuntu2004:multiarch",
+        { TOOLSET: 'gcc', COMPILER: 'g++', CXXSTD: '03,11,14,17,2a', ADDRMD: '64' },
+        arch="s390x",
+    ),
+
+    macos_pipeline(
+        "MacOS 10.15 Xcode 12.2 UBSAN",
+        { TOOLSET: 'clang', COMPILER: 'clang++', CXXSTD: '03,11,14,1z' } + ubsan,
+    ),
+
+    macos_pipeline(
+        "MacOS 12.4 Xcode 13.4.1 ASAN",
+        { TOOLSET: 'clang', COMPILER: 'clang++', CXXSTD: '03,11,14,1z' } + asan,
+        xcode_version = "13.4.1", osx_version = "monterey",
+    ),
+
+    windows_pipeline(
+        "Windows VS2017 msvc-14.1",
+        "cppalliance/dronevs2017",
+        { TOOLSET: 'msvc-14.1', CXXSTD: '14,17,latest' },
+    ),
+]

.drone/drone.bat

@@ -0,0 +1,23 @@
+@REM Copyright 2022 Peter Dimov
+@REM Distributed under the Boost Software License, Version 1.0.
+@REM https://www.boost.org/LICENSE_1_0.txt
+
+@ECHO ON
+
+set LIBRARY=%1
+set DRONE_BUILD_DIR=%CD%
+
+set BOOST_BRANCH=develop
+if "%DRONE_BRANCH%" == "master" set BOOST_BRANCH=master
+cd ..
+git clone -b %BOOST_BRANCH% --depth 1 https://github.com/boostorg/boost.git boost-root
+cd boost-root
+git submodule update --init tools/boostdep
+xcopy /s /e /q %DRONE_BUILD_DIR% libs\%LIBRARY%\
+python tools/boostdep/depinst/depinst.py %LIBRARY%
+cmd /c bootstrap
+b2 -d0 headers
+
+if not "%CXXSTD%" == "" set CXXSTD=cxxstd=%CXXSTD%
+if not "%ADDRMD%" == "" set ADDRMD=address-model=%ADDRMD%
+b2 -j3 libs/%LIBRARY%/test toolset=%TOOLSET% %CXXSTD% %ADDRMD% variant=debug,release embed-manifest-via=linker

.drone/drone.sh

@@ -0,0 +1,25 @@
+#!/bin/bash
+
+# Copyright 2022 Peter Dimov
+# Distributed under the Boost Software License, Version 1.0.
+# https://www.boost.org/LICENSE_1_0.txt
+
+set -ex
+export PATH=~/.local/bin:/usr/local/bin:$PATH
+
+DRONE_BUILD_DIR=$(pwd)
+
+BOOST_BRANCH=develop
+if [ "$DRONE_BRANCH" = "master" ]; then BOOST_BRANCH=master; fi
+
+cd ..
+git clone -b $BOOST_BRANCH --depth 1 https://github.com/boostorg/boost.git boost-root
+cd boost-root
+git submodule update --init tools/boostdep
+cp -r $DRONE_BUILD_DIR/* libs/$LIBRARY
+python tools/boostdep/depinst/depinst.py $LIBRARY
+./bootstrap.sh
+./b2 -d0 headers
+
+echo "using $TOOLSET : : $COMPILER ;" > ~/user-config.jam
+./b2 -j3 libs/$LIBRARY/test toolset=$TOOLSET cxxstd=$CXXSTD variant=debug,release ${ADDRMD:+address-model=$ADDRMD} ${UBSAN:+undefined-sanitizer=norecover debug-symbols=on} ${ASAN:+address-sanitizer=norecover debug-symbols=on} ${LINKFLAGS:+linkflags=$LINKFLAGS}

.github/workflows/ci.yml

@@ -1,3 +1,11 @@
+# Copyright 2020-2021 Peter Dimov
+# Copyright 2021 Andrey Semashev
+# Copyright 2021 Alexander Grund
+# Copyright 2022 James E. King III
+#
+# Distributed under the Boost Software License, Version 1.0.
+# (See accompanying file LICENSE_1_0.txt or copy at http://boost.org/LICENSE_1_0.txt)
+---
 name: CI
 
 on:
@@ -6,207 +14,384 @@ on:
     branches:
       - master
       - develop
+      - bugfix/**
       - feature/**
+      - fix/**
+      - pr/**
+
+concurrency:
+  group: ${{format('{0}:{1}', github.repository, github.ref)}}
+  cancel-in-progress: true
 
 env:
-  UBSAN_OPTIONS: print_stacktrace=1
+  GIT_FETCH_JOBS: 8
+  NET_RETRY_COUNT: 5
+  B2_CI_VERSION: 1
+  B2_VARIANT: debug,release
+  LCOV_BRANCH_COVERAGE: 0
+  CODECOV_NAME: Github Actions
 
 jobs:
   posix:
+    defaults:
+      run:
+        shell: bash
+
     strategy:
       fail-fast: false
       matrix:
         include:
-          - toolset: gcc-4.8
-            cxxstd: "03,11"
-            os: ubuntu-18.04
-            install: g++-4.8
-          - toolset: gcc-5
-            cxxstd: "03,11,14,1z"
-            os: ubuntu-18.04
-            install: g++-5
-          - toolset: gcc-6
-            cxxstd: "03,11,14,1z"
-            os: ubuntu-18.04
-            install: g++-6
-          - toolset: gcc-7
-            cxxstd: "03,11,14,17"
-            os: ubuntu-18.04
-          - toolset: gcc-8
-            cxxstd: "03,11,14,17,2a"
-            os: ubuntu-18.04
-            install: g++-8
-          - toolset: gcc-9
-            cxxstd: "03,11,14,17,2a"
-            os: ubuntu-18.04
-          - toolset: gcc-9
-            cxxstd: "03,11,14,17,2a"
-            os: ubuntu-20.04
-          - toolset: gcc-10
-            cxxstd: "03,11,14,17,2a"
-            os: ubuntu-20.04
-          - toolset: gcc-11
-            cxxstd: "03,11,14,17,2a"
-            os: ubuntu-20.04
-            install: g++-11
-            sanitizers: true
-          - toolset: clang
-            compiler: clang++-3.9
-            cxxstd: "03,11,14"
-            os: ubuntu-18.04
-            install: clang-3.9
-          - toolset: clang
-            compiler: clang++-4.0
-            cxxstd: "03,11,14"
-            os: ubuntu-18.04
-            install: clang-4.0
-          - toolset: clang
-            compiler: clang++-5.0
-            cxxstd: "03,11,14,1z"
-            os: ubuntu-18.04
-            install: clang-5.0
-          - toolset: clang
-            compiler: clang++-6.0
-            cxxstd: "03,11,14,17"
-            os: ubuntu-18.04
-            install: clang-6.0
-          - toolset: clang
-            compiler: clang++-7
-            cxxstd: "03,11,14,17"
-            os: ubuntu-18.04
-            install: clang-7
-          - toolset: clang
-            compiler: clang++-8
-            cxxstd: "03,11,14,17"
-            os: ubuntu-20.04
-            install: clang-8
-          - toolset: clang
-            compiler: clang++-9
-            cxxstd: "03,11,14,17"
-            os: ubuntu-20.04
-            install: clang-9
-          - toolset: clang
-            compiler: clang++-10
-            cxxstd: "03,11,14,17"
-            os: ubuntu-20.04
-          - toolset: clang
-            compiler: clang++-11
-            cxxstd: "03,11,14,17,2a"
-            os: ubuntu-20.04
-          - toolset: clang
-            compiler: clang++-12
-            cxxstd: "03,11,14,17,2a"
-            os: ubuntu-20.04
-            sanitizers: true
-          - toolset: clang
-            cxxstd: "03,11,14,17"
-            os: macos-10.15
-            sanitizers: true
+          # Linux, gcc
+          - { compiler: gcc-4.8,   cxxstd: '03,11',          os: ubuntu-18.04, install: 'g++-4.8-multilib', address-model: '32,64' }
+          - { compiler: gcc-4.9,   cxxstd: '03,11',          os: ubuntu-20.04, container: 'ubuntu:16.04' }
+          - { compiler: gcc-5,     cxxstd: '03,11,14,1z',    os: ubuntu-18.04, install: 'g++-5-multilib', address-model: '32,64' }
+          - { compiler: gcc-6,     cxxstd: '03,11,14,17',    os: ubuntu-18.04, install: 'g++-6-multilib', address-model: '32,64' }
+          - { compiler: gcc-7,     cxxstd: '03,11,14,17',    os: ubuntu-18.04, install: 'g++-7-multilib', address-model: '32,64' }
+          - { compiler: gcc-8,     cxxstd: '03,11,14,17,2a', os: ubuntu-18.04, install: 'g++-8-multilib', address-model: '32,64' }
+          - { compiler: gcc-9,     cxxstd: '03,11,14,17,2a', os: ubuntu-18.04, install: 'g++-9-multilib', address-model: '32,64' }
+          - { compiler: gcc-10,    cxxstd: '03,11,14,17,20', os: ubuntu-20.04, install: 'g++-10-multilib', address-model: '32,64' }
+          - { compiler: gcc-11,    cxxstd: '03,11,14,17,20', os: ubuntu-20.04, install: 'g++-11-multilib', address-model: '32,64' }
+          - { compiler: gcc-12,    cxxstd: '03,11,14,17,20', os: ubuntu-22.04, install: 'g++-12-multilib', address-model: '32,64' }
+          - { name: GCC w/ sanitizers, sanitize: yes,
+              compiler: gcc-12,    cxxstd: '03,11,14,17,20', os: ubuntu-22.04 }
+          - { name: Collect coverage, coverage: yes,
+              compiler: gcc-8,     cxxstd: '03,11',          os: ubuntu-20.04, install: 'g++-8-multilib', address-model: '32,64' }
 
+          # Linux, clang
+          - { compiler: clang-3.7, cxxstd: '03,11,14',       os: ubuntu-20.04, container: 'ubuntu:16.04' }
+          - { compiler: clang-3.8, cxxstd: '03,11,14',       os: ubuntu-20.04, container: 'ubuntu:16.04' }
+          - { compiler: clang-3.9, cxxstd: '03,11,14',       os: ubuntu-18.04 }
+          - { compiler: clang-4.0, cxxstd: '03,11,14',       os: ubuntu-18.04 }
+          - { compiler: clang-5.0, cxxstd: '03,11,14,1z',    os: ubuntu-18.04 }
+          - { compiler: clang-6.0, cxxstd: '03,11,14,17',    os: ubuntu-18.04 }
+          - { compiler: clang-7,   cxxstd: '03,11,14,17',    os: ubuntu-18.04 }
+          - { compiler: clang-8,   cxxstd: '03,11,14,17',    os: ubuntu-18.04 }
+          - { compiler: clang-9,   cxxstd: '03,11,14,17,2a', os: ubuntu-20.04 }
+          - { compiler: clang-10,  cxxstd: '03,11,14,17,20', os: ubuntu-20.04 }
+          - { compiler: clang-11,  cxxstd: '03,11,14,17,20', os: ubuntu-20.04 }
+          - { compiler: clang-12,  cxxstd: '03,11,14,17,20', os: ubuntu-20.04 }
+          - { compiler: clang-13,  cxxstd: '03,11,14,17,20', os: ubuntu-22.04 }
+          - { compiler: clang-14,  cxxstd: '03,11,14,17,20', os: ubuntu-22.04 }
+
+          # libc++
+          - { compiler: clang-6.0, cxxstd: '03,11,14',       os: ubuntu-18.04, stdlib: libc++, install: 'clang-6.0 libc++-dev libc++abi-dev' }
+          - { compiler: clang-12,  cxxstd: '03,11,14,17,20', os: ubuntu-20.04, stdlib: libc++, install: 'clang-12 libc++-12-dev libc++abi-12-dev' }
+          - { name: Clang w/ sanitizers, sanitize: yes,
+              compiler: clang-12,  cxxstd: '03,11,14,17,20', os: ubuntu-20.04, stdlib: libc++, install: 'clang-12 libc++-12-dev libc++abi-12-dev' }
+
+          # OSX, clang
+          - { compiler: clang,     cxxstd: '03,11,14,17,2a', os: macos-11, sanitize: yes }
+
+    timeout-minutes: 120
     runs-on: ${{matrix.os}}
+    container: ${{matrix.container}}
+    env: {B2_USE_CCACHE: 1}
 
     steps:
-      - uses: actions/checkout@v2
+      - name: Setup environment
+        run: |
+            if [ -f "/etc/debian_version" ]; then
+                echo "DEBIAN_FRONTEND=noninteractive" >> $GITHUB_ENV
+                export DEBIAN_FRONTEND=noninteractive
+            fi
+            if [ -n "${{matrix.container}}" ] && [ -f "/etc/debian_version" ]; then
+                apt-get -o Acquire::Retries=$NET_RETRY_COUNT update
+                apt-get -o Acquire::Retries=$NET_RETRY_COUNT install -y sudo software-properties-common
+                # Need (newer) git, and the older Ubuntu container may require requesting the key manually using port 80
+                apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys E1DD270288B4E6030699E45FA1715D88E1DF1F24
+                for i in {1..${NET_RETRY_COUNT:-3}}; do sudo -E add-apt-repository -y ppa:git-core/ppa && break || sleep 10; done
+                apt-get -o Acquire::Retries=$NET_RETRY_COUNT update
+                apt-get -o Acquire::Retries=$NET_RETRY_COUNT install -y g++ python libpython-dev git
+            fi
+            # For jobs not compatible with ccache, use "ccache: no" in the matrix
+            if [[ "${{ matrix.ccache }}" == "no" ]]; then
+                echo "B2_USE_CCACHE=0" >> $GITHUB_ENV
+            fi
+            git config --global pack.threads 0
+
+      - uses: actions/checkout@v3
+        with:
+          # For coverage builds fetch the whole history, else only 1 commit using a 'fake ternary'
+          fetch-depth: ${{ matrix.coverage && '0' || '1' }}
+
+      - name: Cache ccache
+        uses: actions/cache@v3
+        if: env.B2_USE_CCACHE
+        with:
+          path: ~/.ccache
+          key: ${{matrix.os}}-${{matrix.container}}-${{matrix.compiler}}-${{github.sha}}
+          restore-keys: ${{matrix.os}}-${{matrix.container}}-${{matrix.compiler}}-
+
+      - name: Fetch Boost.CI
+        uses: actions/checkout@v3
+        with:
+          repository: boostorg/boost-ci
+          ref: master
+          path: boost-ci-cloned
+
+      - name: Get CI scripts folder
+        run: |
+            # Copy ci folder if not testing Boost.CI
+            [[ "$GITHUB_REPOSITORY" =~ "boost-ci" ]] || cp -r boost-ci-cloned/ci .
+            rm -rf boost-ci-cloned
 
       - name: Install packages
-        if: matrix.install
-        run: sudo apt install ${{matrix.install}}
+        if: startsWith(matrix.os, 'ubuntu')
+        run: |
+            SOURCE_KEYS=(${{join(matrix.source_keys, ' ')}})
+            SOURCES=(${{join(matrix.sources, ' ')}})
+            # Add this by default
+            SOURCES+=(ppa:ubuntu-toolchain-r/test)
+            for key in "${SOURCE_KEYS[@]}"; do
+                for i in {1..$NET_RETRY_COUNT}; do
+                    wget -O - "$key" | sudo apt-key add - && break || sleep 10
+                done
+            done
+            for source in "${SOURCES[@]}"; do
+                for i in {1..$NET_RETRY_COUNT}; do
+                    sudo add-apt-repository $source && break || sleep 10
+                done
+            done
+            sudo apt-get -o Acquire::Retries=$NET_RETRY_COUNT update
+            if [[ -z "${{matrix.install}}" ]]; then
+                pkgs="${{matrix.compiler}}"
+                pkgs="${pkgs/gcc-/g++-}"
+            else
+                pkgs="${{matrix.install}}"
+            fi
+            sudo apt-get -o Acquire::Retries=$NET_RETRY_COUNT install -y $pkgs
+
+      - name: Setup GCC Toolchain
+        if: matrix.gcc_toolchain
+        run: |
+            GCC_TOOLCHAIN_ROOT="$HOME/gcc-toolchain"
+            echo "GCC_TOOLCHAIN_ROOT=$GCC_TOOLCHAIN_ROOT" >> $GITHUB_ENV
+            MULTIARCH_TRIPLET="$(dpkg-architecture -qDEB_HOST_MULTIARCH)"
+            mkdir -p "$GCC_TOOLCHAIN_ROOT"
+            ln -s /usr/include "$GCC_TOOLCHAIN_ROOT/include"
+            ln -s /usr/bin "$GCC_TOOLCHAIN_ROOT/bin"
+            mkdir -p "$GCC_TOOLCHAIN_ROOT/lib/gcc/$MULTIARCH_TRIPLET"
+            ln -s "/usr/lib/gcc/$MULTIARCH_TRIPLET/${{matrix.gcc_toolchain}}" "$GCC_TOOLCHAIN_ROOT/lib/gcc/$MULTIARCH_TRIPLET/${{matrix.gcc_toolchain}}"
+
+      - name: Setup multiarch
+        if: matrix.multiarch
+        run: |
+          sudo apt-get install --no-install-recommends -y binfmt-support qemu-user-static
+          sudo docker run --rm --privileged multiarch/qemu-user-static --reset -p yes
+          git clone https://github.com/jeking3/bdde.git
+          echo "$(pwd)/bdde/bin/linux" >> ${GITHUB_PATH}
+          echo "BDDE_DISTRO=${{ matrix.distro }}" >> ${GITHUB_ENV}
+          echo "BDDE_EDITION=${{ matrix.edition }}" >> ${GITHUB_ENV}
+          echo "BDDE_ARCH=${{ matrix.arch }}" >> ${GITHUB_ENV}
+          echo "B2_WRAPPER=bdde" >> ${GITHUB_ENV}
 
       - name: Setup Boost
-        run: |
-          echo GITHUB_REPOSITORY: $GITHUB_REPOSITORY
-          LIBRARY=${GITHUB_REPOSITORY#*/}
-          echo LIBRARY: $LIBRARY
-          echo "LIBRARY=$LIBRARY" >> $GITHUB_ENV
-          echo GITHUB_BASE_REF: $GITHUB_BASE_REF
-          echo GITHUB_REF: $GITHUB_REF
-          REF=${GITHUB_BASE_REF:-$GITHUB_REF}
-          REF=${REF#refs/heads/}
-          echo REF: $REF
-          BOOST_BRANCH=develop && [ "$REF" == "master" ] && BOOST_BRANCH=master || true
-          echo BOOST_BRANCH: $BOOST_BRANCH
-          cd ..
-          git clone -b $BOOST_BRANCH --depth 1 https://github.com/boostorg/boost.git boost-root
-          cd boost-root
-          cp -r $GITHUB_WORKSPACE/* libs/$LIBRARY
-          git submodule update --init tools/boostdep
-          python tools/boostdep/depinst/depinst.py --git_args "--jobs 3" $LIBRARY
-          ./bootstrap.sh
-          ./b2 -d0 headers
+        env:
+          B2_ADDRESS_MODEL: ${{matrix.address-model}}
+          B2_COMPILER: ${{matrix.compiler}}
+          B2_CXXSTD: ${{matrix.cxxstd}}
+          B2_SANITIZE: ${{matrix.sanitize}}
+          B2_STDLIB: ${{matrix.stdlib}}
+          # More entries can be added in the same way, see the B2_ARGS assignment in ci/enforce.sh for the possible keys.
+          # B2_DEFINES: ${{matrix.defines}}
+          # Variables set here (to non-empty) will override the top-level environment variables, e.g.
+          # B2_VARIANT: ${{matrix.variant}}
+        run: source ci/github/install.sh
 
-      - name: Create user-config.jam
-        if: matrix.compiler
-        run: |
-          echo "using ${{matrix.toolset}} : : ${{matrix.compiler}} ;" > ~/user-config.jam
+      - name: Setup coverage collection
+        if: matrix.coverage
+        run: ci/github/codecov.sh "setup"
 
       - name: Run tests
-        run: |
-          cd ../boost-root
-          ./b2 -j3 libs/$LIBRARY/test \
-                   toolset=${{matrix.toolset}} \
-                   cxxstd=${{matrix.cxxstd}} \
-                   variant=debug,release \
-                   ${{(matrix.sanitizers && 'address-sanitizer=norecover undefined-sanitizer=norecover') || ''}}
+        if: '!matrix.coverity'
+        run: ci/build.sh
+
+      - name: Upload coverage
+        if: matrix.coverage
+        run: ci/codecov.sh "upload"
+
+      - name: Run coverity
+        if: matrix.coverity && github.event_name == 'push' && (github.ref_name == 'develop' || github.ref_name == 'master')
+        run: ci/github/coverity.sh
+        env:
+          COVERITY_SCAN_NOTIFICATION_EMAIL: ${{ secrets.COVERITY_SCAN_NOTIFICATION_EMAIL }}
+          COVERITY_SCAN_TOKEN: ${{ secrets.COVERITY_SCAN_TOKEN }}
 
   windows:
+    defaults:
+      run:
+        shell: cmd
     strategy:
       fail-fast: false
       matrix:
         include:
-          - toolset: msvc-14.0
-            cxxstd: 14,latest
-            addrmd: 32,64
-            os: windows-2019
-          - toolset: msvc-14.1
-            cxxstd: "14,17,latest"
-            addrmd: 32,64
-            os: windows-2016
-          - toolset: msvc-14.2
-            cxxstd: "14,17,20,latest"
-            addrmd: 32,64
-            os: windows-2019
-          - toolset: msvc-14.3
-            cxxstd: "14,17,20,latest"
-            addrmd: 32,64
-            os: windows-2022
-          - toolset: clang-win
-            cxxstd: "14,17,latest"
-            addrmd: 32,64
-            os: windows-2022
-          - toolset: gcc
-            cxxstd: "03,11,14,17,2a"
-            addrmd: 64
-            os: windows-2019
+          - { toolset: msvc-14.0, cxxstd: '14,latest',       addrmd: '32,64', os: windows-2019 }
+          - { toolset: msvc-14.2, cxxstd: '14,17,20,latest', addrmd: '32,64', os: windows-2019 }
+          - { toolset: msvc-14.3, cxxstd: '14,17,20,latest', addrmd: '32,64', os: windows-2022 }
+          - { toolset: clang-win, cxxstd: '14,17,latest',    addrmd: '32,64', os: windows-2022 }
+          - { toolset: gcc,       cxxstd: '03,11,14,17,2a',  addrmd: '64',    os: windows-2019 }
 
     runs-on: ${{matrix.os}}
 
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
+
+      - name: Fetch Boost.CI
+        uses: actions/checkout@v3
+        with:
+          repository: boostorg/boost-ci
+          ref: master
+          path: boost-ci-cloned
+      - name: Get CI scripts folder
+        run: |
+            REM Copy ci folder if not testing Boost.CI
+            if "%GITHUB_REPOSITORY%" == "%GITHUB_REPOSITORY:boost-ci=%" xcopy /s /e /q /i /y boost-ci-cloned\ci .\ci
+            rmdir /s /q boost-ci-cloned
 
       - name: Setup Boost
-        shell: cmd
-        run: |
-          echo GITHUB_REPOSITORY: %GITHUB_REPOSITORY%
-          for /f %%i in ("%GITHUB_REPOSITORY%") do set LIBRARY=%%~nxi
-          echo LIBRARY: %LIBRARY%
-          echo LIBRARY=%LIBRARY%>>%GITHUB_ENV%
-          echo GITHUB_BASE_REF: %GITHUB_BASE_REF%
-          echo GITHUB_REF: %GITHUB_REF%
-          if "%GITHUB_BASE_REF%" == "" set GITHUB_BASE_REF=%GITHUB_REF%
-          set BOOST_BRANCH=develop
-          for /f %%i in ("%GITHUB_BASE_REF%") do if "%%~nxi" == "master" set BOOST_BRANCH=master
-          echo BOOST_BRANCH: %BOOST_BRANCH%
-          cd ..
-          git clone -b %BOOST_BRANCH% --depth 1 https://github.com/boostorg/boost.git boost-root
-          cd boost-root
-          xcopy /s /e /q %GITHUB_WORKSPACE% libs\%LIBRARY%\
-          git submodule update --init tools/boostdep
-          python tools/boostdep/depinst/depinst.py --git_args "--jobs 3" %LIBRARY%
-          cmd /c bootstrap
-          b2 -d0 headers
+        run: ci\github\install.bat
 
       - name: Run tests
-        shell: cmd
+        if: '!matrix.coverage'
+        run: ci\build.bat
+        env:
+          B2_TOOLSET: ${{matrix.toolset}}
+          B2_CXXSTD: ${{matrix.cxxstd}}
+          B2_ADDRESS_MODEL: ${{matrix.addrmd}}
+
+      - name: Collect coverage
+        shell: powershell
+        if: matrix.coverage
+        run: ci\opencppcoverage.ps1
+        env:
+          B2_TOOLSET: ${{matrix.toolset}}
+          B2_CXXSTD: ${{matrix.cxxstd}}
+          B2_ADDRESS_MODEL: ${{matrix.addrmd}}
+
+      - name: Upload coverage
+        if: matrix.coverage
+        uses: codecov/codecov-action@v2
+        with:
+          files: __out/cobertura.xml
+
+  MSYS2:
+    defaults:
+      run:
+        shell: msys2 {0}
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - { sys: MINGW32, compiler: gcc, cxxstd: '03,11,17,20' }
+          - { sys: MINGW64, compiler: gcc, cxxstd: '03,11,17,20' }
+
+    runs-on: windows-latest
+
+    steps:
+      - uses: actions/checkout@v3
+
+      - name: Setup MSYS2 environment
+        uses: msys2/setup-msys2@v2
+        with:
+          msystem: ${{matrix.sys}}
+          update: true
+          install: git python
+          pacboy: gcc:p cmake:p ninja:p
+
+      - name: Fetch Boost.CI
+        uses: actions/checkout@v3
+        with:
+          repository: boostorg/boost-ci
+          ref: master
+          path: boost-ci-cloned
+      - name: Get CI scripts folder
         run: |
-          cd ../boost-root
-          b2 -j3 libs/%LIBRARY%/test toolset=${{matrix.toolset}} cxxstd=${{matrix.cxxstd}} address-model=${{matrix.addrmd}} variant=debug,release embed-manifest-via=linker
+            # Copy ci folder if not testing Boost.CI
+            [[ "$GITHUB_REPOSITORY" =~ "boost-ci" ]] || cp -r boost-ci-cloned/ci .
+            rm -rf boost-ci-cloned
+
+      - name: Setup Boost
+        env:
+          B2_COMPILER: ${{matrix.compiler}}
+          B2_CXXSTD: ${{matrix.cxxstd}}
+          B2_SANITIZE: ${{matrix.sanitize}}
+          B2_STDLIB: ${{matrix.stdlib}}
+        run: ci/github/install.sh
+
+      - name: Run tests
+        run: ci/build.sh
+
+      # Run also the CMake tests to avoid having to setup another matrix for CMake on MSYS
+      - name: Run CMake tests
+        run: |
+            cd "$BOOST_ROOT"
+            mkdir __build_cmake_test__ && cd __build_cmake_test__
+            cmake -G Ninja -DCMAKE_BUILD_TYPE=Debug -DBOOST_INCLUDE_LIBRARIES=$SELF -DBUILD_SHARED_LIBS=ON -DBUILD_TESTING=ON -DBoost_VERBOSE=ON ..
+            cmake --build . --target tests --config Debug -j$B2_JOBS
+            ctest --output-on-failure --build-config Debug
+
+  CMake:
+    defaults:
+      run:
+        shell: bash
+
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - { os: ubuntu-20.04, build_shared: ON,  build_type: Debug, generator: 'Unix Makefiles' }
+          - { os: windows-2019, build_shared: ON,  build_type: Debug, generator: 'Visual Studio 16 2019' }
+
+    timeout-minutes: 120
+    runs-on: ${{matrix.os}}
+
+    steps:
+      - uses: actions/checkout@v3
+      - name: Fetch Boost.CI
+        uses: actions/checkout@v3
+        with:
+          repository: boostorg/boost-ci
+          ref: master
+          path: boost-ci-cloned
+      - name: Get CI scripts folder
+        run: |
+            # Copy ci folder if not testing Boost.CI
+            [[ "$GITHUB_REPOSITORY" =~ "boost-ci" ]] || cp -r boost-ci-cloned/ci .
+            rm -rf boost-ci-cloned
+      - name: Setup Boost
+        env: {B2_DONT_BOOTSTRAP: 1}
+        run: source ci/github/install.sh
+
+      - name: Run CMake tests
+        run: |
+            cd "$BOOST_ROOT"
+            mkdir __build_cmake_test__ && cd __build_cmake_test__
+            cmake -G "${{matrix.generator}}" -DCMAKE_BUILD_TYPE=${{matrix.build_type}} -DBOOST_INCLUDE_LIBRARIES=$SELF -DBUILD_SHARED_LIBS=${{matrix.build_shared}} -DBUILD_TESTING=ON -DBoost_VERBOSE=ON ..
+            cmake --build . --target tests --config ${{matrix.build_type}} -j$B2_JOBS
+            ctest --output-on-failure --build-config ${{matrix.build_type}}
+
+      - name: Run CMake subdir tests
+        run: |
+            cmake_test_folder="$BOOST_ROOT/libs/$SELF/test/cmake_test" # New unified folder
+            [ -d "$cmake_test_folder" ] || cmake_test_folder="$BOOST_ROOT/libs/$SELF/test/cmake_subdir_test"
+            cd "$cmake_test_folder"
+            mkdir __build_cmake_subdir_test__ && cd __build_cmake_subdir_test__
+            cmake -G "${{matrix.generator}}" -DBOOST_CI_INSTALL_TEST=OFF -DCMAKE_BUILD_TYPE=${{matrix.build_type}} -DBUILD_SHARED_LIBS=${{matrix.build_shared}} ..
+            cmake --build . --config ${{matrix.build_type}} -j$B2_JOBS
+            ctest --output-on-failure --build-config ${{matrix.build_type}}
+
+      - name: Install Library
+        run: |
+            cd "$BOOST_ROOT"
+            mkdir __build_cmake_install_test__ && cd __build_cmake_install_test__
+            cmake -G "${{matrix.generator}}" -DCMAKE_BUILD_TYPE=${{matrix.build_type}} -DBOOST_INCLUDE_LIBRARIES=$SELF -DBUILD_SHARED_LIBS=${{matrix.build_shared}} -DCMAKE_INSTALL_PREFIX=~/.local -DBoost_VERBOSE=ON -DBoost_DEBUG=ON ..
+            cmake --build . --target install --config ${{matrix.build_type}} -j$B2_JOBS
+      - name: Run CMake install tests
+        run: |
+            cmake_test_folder="$BOOST_ROOT/libs/$SELF/test/cmake_test" # New unified folder
+            [ -d "$cmake_test_folder" ] || cmake_test_folder="$BOOST_ROOT/libs/$SELF/test/cmake_install_test"
+            cd "$cmake_test_folder"
+            mkdir __build_cmake_install_test__ && cd __build_cmake_install_test__
+            cmake -G "${{matrix.generator}}" -DBOOST_CI_INSTALL_TEST=ON -DCMAKE_BUILD_TYPE=${{matrix.build_type}} -DBUILD_SHARED_LIBS=${{matrix.build_shared}} -DCMAKE_PREFIX_PATH=~/.local ..
+            cmake --build . --config ${{matrix.build_type}} -j$B2_JOBS
+            ctest --output-on-failure --build-config ${{matrix.build_type}}

CMakeLists.txt

@@ -1,9 +1,9 @@
 # Generated by `boostdep --cmake unordered`
-# Copyright 2020 Peter Dimov
+# Copyright 2020, 2021 Peter Dimov
 # Distributed under the Boost Software License, Version 1.0.
 # https://www.boost.org/LICENSE_1_0.txt
 
-cmake_minimum_required(VERSION 3.5...3.16)
+cmake_minimum_required(VERSION 3.5...3.20)
 
 project(boost_unordered VERSION "${BOOST_SUPERPROJECT_VERSION}" LANGUAGES CXX)
 
@@ -16,14 +16,12 @@ target_link_libraries(boost_unordered
   INTERFACE
     Boost::assert
     Boost::config
-    Boost::container
     Boost::container_hash
     Boost::core
-    Boost::detail
     Boost::move
+    Boost::mp11
     Boost::predef
     Boost::preprocessor
-    Boost::smart_ptr
     Boost::throw_exception
     Boost::tuple
     Boost::type_traits
@@ -34,4 +32,3 @@ if(BUILD_TESTING AND EXISTS "${CMAKE_CURRENT_SOURCE_DIR}/test/CMakeLists.txt")
   add_subdirectory(test)
 
 endif()
-

LICENSE

@@ -0,0 +1,23 @@
+Boost Software License - Version 1.0 - August 17th, 2003
+
+Permission is hereby granted, free of charge, to any person or organization
+obtaining a copy of the software and accompanying documentation covered by
+this license (the "Software") to use, reproduce, display, distribute,
+execute, and transmit the Software, and to prepare derivative works of the
+Software, and to permit third-parties to whom the Software is furnished to
+do so, all subject to the following:
+
+The copyright notices in the Software and this entire statement, including
+the above license grant, this restriction and the following disclaimer,
+must be included in all copies of the Software, in whole or in part, and
+all derivative works of the Software, unless such copies or derivative
+works are solely in the form of machine-executable object code generated by
+a source language processor.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
+SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
+FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
+ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+DEALINGS IN THE SOFTWARE.

README.md

@@ -0,0 +1,49 @@
+# Boost.Unordered
+
+Part of collection of the [Boost C++ Libraries](http://github.com/boostorg).
+
+For accessing data based on key lookup, the C++ standard library offers `std::set`, `std::map`, `std::multiset` and `std::multimap`.
+These are generally implemented using balanced binary trees so that lookup time has logarithmic complexity.
+That is generally okay, but in many cases a hash table can perform better, as accessing data has constant complexity, on average.
+The worst case complexity is linear, but that occurs rarely and with some care, can be avoided.
+
+Also, the existing containers require a 'less than' comparison object to order their elements.
+For some data types this is impossible to implement or isn’t practical.
+In contrast, a hash table only needs an equality function and a hash function for the key.
+
+With this in mind, unordered associative containers were added to the C++ standard.
+This is an implementation of the containers described in C++11, with some deviations from the standard in order to work with non-C++11 compilers and libraries.
+
+
+### License
+
+Distributed under the [Boost Software License, Version 1.0](http://www.boost.org/LICENSE_1_0.txt).
+
+### Properties
+
+* C++03
+* Header-Only
+
+### Build Status
+
+Branch          | GH Actions | Appveyor | codecov.io | Deps | Docs | Tests |
+:-------------: | ---------- | -------- | ---------- | ---- | ---- | ----- |
+[`master`](https://github.com/boostorg/unordered/tree/master)   | [![CI](https://github.com/boostorg/unordered/actions/workflows/ci.yml/badge.svg?branch=master)](https://github.com/boostorg/unordered/actions/workflows/ci.yml)  | [![Build status](https://ci.appveyor.com/api/projects/status/github/boostorg/unordered?branch=master&svg=true)](https://ci.appveyor.com/project/danieljames/unordered-qtwe6/branch/master)   | [![codecov](https://codecov.io/gh/boostorg/unordered/branch/master/graph/badge.svg)](https://codecov.io/gh/boostorg/unordered/branch/master)   | [![Deps](https://img.shields.io/badge/deps-master-brightgreen.svg)](https://pdimov.github.io/boostdep-report/master/unordered.html)   | [![Documentation](https://img.shields.io/badge/docs-master-brightgreen.svg)](https://www.boost.org/doc/libs/master/libs/unordered/doc/html/unordered.html)   | [![Enter the Matrix](https://img.shields.io/badge/matrix-master-brightgreen.svg)](http://www.boost.org/development/tests/master/developer/unordered.html)
+[`develop`](https://github.com/boostorg/unordered/tree/develop) | [![CI](https://github.com/boostorg/unordered/actions/workflows/ci.yml/badge.svg?branch=develop)](https://github.com/boostorg/unordered/actions/workflows/ci.yml) | [![Build status](https://ci.appveyor.com/api/projects/status/github/boostorg/unordered?branch=develop&svg=true)](https://ci.appveyor.com/project/danieljames/unordered-qtwe6/branch/develop) | [![codecov](https://codecov.io/gh/boostorg/unordered/branch/develop/graph/badge.svg)](https://codecov.io/gh/boostorg/unordered/branch/develop) | [![Deps](https://img.shields.io/badge/deps-develop-brightgreen.svg)](https://pdimov.github.io/boostdep-report/develop/unordered.html) | [![Documentation](https://img.shields.io/badge/docs-develop-brightgreen.svg)](https://www.boost.org/doc/libs/develop/libs/unordered/doc/html/unordered.html) | [![Enter the Matrix](https://img.shields.io/badge/matrix-develop-brightgreen.svg)](http://www.boost.org/development/tests/develop/developer/unordered.html)
+
+### Directories
+
+| Name        | Purpose                        |
+| ----------- | ------------------------------ |
+| `doc`       | documentation                  |
+| `example`   | examples                       |
+| `include`   | headers                        |
+| `test`      | unit tests                     |
+
+### More information
+
+* [Ask questions](http://stackoverflow.com/questions/ask?tags=c%2B%2B,boost,boost-unordered)
+* [Report bugs](https://github.com/boostorg/unordered/issues): Be sure to mention Boost version, platform and compiler you're using. A small compilable code sample to reproduce the problem is always good as well.
+* Submit your patches as pull requests against **develop** branch. Note that by submitting patches you agree to license your modifications under the [Boost Software License, Version 1.0](http://www.boost.org/LICENSE_1_0.txt).
+* Discussions about the library are held on the [Boost developers mailing list](http://www.boost.org/community/groups.html#main). Be sure to read the [discussion policy](http://www.boost.org/community/policy.html) before posting and add the `[unordered]` tag at the beginning of the subject line.
+

benchmark/string.cpp

@@ -14,6 +14,12 @@
 # include "absl/container/node_hash_map.h"
 # include "absl/container/flat_hash_map.h"
 #endif
+#ifdef HAVE_TSL_HOPSCOTCH
+# include "tsl/hopscotch_map.h"
+#endif
+#ifdef HAVE_TSL_ROBIN
+# include "tsl/robin_map.h"
+#endif
 #include <unordered_map>
 #include <vector>
 #include <memory>
@@ -137,7 +143,14 @@ template<class Map> BOOST_NOINLINE void test_iteration( Map& map, std::chrono::s
     {
         if( it->second & 1 )
         {
-            map.erase( it++ );
+            if constexpr( std::is_void_v< decltype( map.erase( it ) ) > )
+            {
+                map.erase( it++ );
+            }
+            else
+            {
+                it = map.erase( it );
+            }
         }
         else
         {
@@ -159,13 +172,9 @@ template<class Map> BOOST_NOINLINE void test_erase( Map& map, std::chrono::stead
 
     print_time( t1, "Consecutive erase",  0, map.size() );
 
+    for( unsigned i = 1; i <= N; ++i )
     {
-        boost::detail::splitmix64 rng;
-
-        for( unsigned i = 1; i <= N; ++i )
-        {
-            map.erase( indices2[ i ] );
-        }
+        map.erase( indices2[ i ] );
     }
 
     print_time( t1, "Random erase",  0, map.size() );
@@ -295,6 +304,26 @@ template<class K, class V> using absl_flat_hash_map =
 
 #endif
 
+#ifdef HAVE_TSL_HOPSCOTCH
+
+template<class K, class V> using tsl_hopscotch_map =
+    tsl::hopscotch_map<K, V, std::hash<K>, std::equal_to<K>, ::allocator< std::pair<K, V> >>;
+
+template<class K, class V> using tsl_hopscotch_pg_map =
+    tsl::hopscotch_pg_map<K, V, std::hash<K>, std::equal_to<K>, ::allocator< std::pair<K, V> >>;
+
+#endif
+
+#ifdef HAVE_TSL_ROBIN
+
+template<class K, class V> using tsl_robin_map =
+    tsl::robin_map<K, V, std::hash<K>, std::equal_to<K>, ::allocator< std::pair<K, V> >>;
+
+template<class K, class V> using tsl_robin_pg_map =
+    tsl::robin_pg_map<K, V, std::hash<K>, std::equal_to<K>, ::allocator< std::pair<K, V> >>;
+
+#endif
+
 // fnv1a_hash
 
 template<int Bits> struct fnv1a_hash_impl;
@@ -363,6 +392,26 @@ template<class K, class V> using absl_flat_hash_map_fnv1a =
 
 #endif
 
+#ifdef HAVE_TSL_HOPSCOTCH
+
+template<class K, class V> using tsl_hopscotch_map_fnv1a =
+    tsl::hopscotch_map<K, V, fnv1a_hash, std::equal_to<K>, ::allocator< std::pair<K, V> >>;
+
+template<class K, class V> using tsl_hopscotch_pg_map_fnv1a =
+    tsl::hopscotch_pg_map<K, V, fnv1a_hash, std::equal_to<K>, ::allocator< std::pair<K, V> >>;
+
+#endif
+
+#ifdef HAVE_TSL_ROBIN
+
+template<class K, class V> using tsl_robin_map_fnv1a =
+    tsl::robin_map<K, V, fnv1a_hash, std::equal_to<K>, ::allocator< std::pair<K, V> >>;
+
+template<class K, class V> using tsl_robin_pg_map_fnv1a =
+    tsl::robin_pg_map<K, V, fnv1a_hash, std::equal_to<K>, ::allocator< std::pair<K, V> >>;
+
+#endif
+
 //
 
 int main()
@@ -382,6 +431,20 @@ int main()
 
 #endif
 
+#ifdef HAVE_TSL_HOPSCOTCH
+
+    test<tsl_hopscotch_map>( "tsl::hopscotch_map" );
+    test<tsl_hopscotch_pg_map>( "tsl::hopscotch_pg_map" );
+
+#endif
+
+#ifdef HAVE_TSL_ROBIN
+
+    test<tsl_robin_map>( "tsl::robin_map" );
+    test<tsl_robin_pg_map>( "tsl::robin_pg_map" );
+
+#endif
+
 #endif
 
     test<std_unordered_map_fnv1a>( "std::unordered_map, FNV-1a" );
@@ -393,13 +456,27 @@ int main()
     test<absl_node_hash_map_fnv1a>( "absl::node_hash_map, FNV-1a" );
     test<absl_flat_hash_map_fnv1a>( "absl::flat_hash_map, FNV-1a" );
 
+#endif
+
+#ifdef HAVE_TSL_HOPSCOTCH
+
+    test<tsl_hopscotch_map_fnv1a>( "tsl::hopscotch_map, FNV-1a" );
+    test<tsl_hopscotch_pg_map_fnv1a>( "tsl::hopscotch_pg_map, FNV-1a" );
+
+#endif
+
+#ifdef HAVE_TSL_ROBIN
+
+    test<tsl_robin_map_fnv1a>( "tsl::robin_map, FNV-1a" );
+    test<tsl_robin_pg_map_fnv1a>( "tsl::robin_pg_map, FNV-1a" );
+
 #endif
 
     std::cout << "---\n\n";
 
     for( auto const& x: times )
     {
-        std::cout << std::setw( 30 ) << ( x.label_ + ": " ) << std::setw( 5 ) << x.time_ << " ms, " << std::setw( 9 ) << x.bytes_ << " bytes in " << x.count_ << " allocations\n";
+        std::cout << std::setw( 31 ) << ( x.label_ + ": " ) << std::setw( 5 ) << x.time_ << " ms, " << std::setw( 9 ) << x.bytes_ << " bytes in " << x.count_ << " allocations\n";
     }
 }
 

benchmark/string_view.cpp

@@ -14,6 +14,12 @@
 # include "absl/container/node_hash_map.h"
 # include "absl/container/flat_hash_map.h"
 #endif
+#ifdef HAVE_TSL_HOPSCOTCH
+# include "tsl/hopscotch_map.h"
+#endif
+#ifdef HAVE_TSL_ROBIN
+# include "tsl/robin_map.h"
+#endif
 #include <unordered_map>
 #include <string_view>
 #include <vector>
@@ -138,7 +144,14 @@ template<class Map> BOOST_NOINLINE void test_iteration( Map& map, std::chrono::s
     {
         if( it->second & 1 )
         {
-            map.erase( it++ );
+            if constexpr( std::is_void_v< decltype( map.erase( it ) ) > )
+            {
+                map.erase( it++ );
+            }
+            else
+            {
+                it = map.erase( it );
+            }
         }
         else
         {
@@ -160,13 +173,9 @@ template<class Map> BOOST_NOINLINE void test_erase( Map& map, std::chrono::stead
 
     print_time( t1, "Consecutive erase",  0, map.size() );
 
+    for( unsigned i = 1; i <= N; ++i )
     {
-        boost::detail::splitmix64 rng;
-
-        for( unsigned i = 1; i <= N; ++i )
-        {
-            map.erase( indices2[ i ] );
-        }
+        map.erase( indices2[ i ] );
     }
 
     print_time( t1, "Random erase",  0, map.size() );
@@ -296,6 +305,26 @@ template<class K, class V> using absl_flat_hash_map =
 
 #endif
 
+#ifdef HAVE_TSL_HOPSCOTCH
+
+template<class K, class V> using tsl_hopscotch_map =
+    tsl::hopscotch_map<K, V, std::hash<K>, std::equal_to<K>, ::allocator< std::pair<K, V> >>;
+
+template<class K, class V> using tsl_hopscotch_pg_map =
+    tsl::hopscotch_pg_map<K, V, std::hash<K>, std::equal_to<K>, ::allocator< std::pair<K, V> >>;
+
+#endif
+
+#ifdef HAVE_TSL_ROBIN
+
+template<class K, class V> using tsl_robin_map =
+    tsl::robin_map<K, V, std::hash<K>, std::equal_to<K>, ::allocator< std::pair<K, V> >>;
+
+template<class K, class V> using tsl_robin_pg_map =
+    tsl::robin_pg_map<K, V, std::hash<K>, std::equal_to<K>, ::allocator< std::pair<K, V> >>;
+
+#endif
+
 // fnv1a_hash
 
 template<int Bits> struct fnv1a_hash_impl;
@@ -364,6 +393,26 @@ template<class K, class V> using absl_flat_hash_map_fnv1a =
 
 #endif
 
+#ifdef HAVE_TSL_HOPSCOTCH
+
+template<class K, class V> using tsl_hopscotch_map_fnv1a =
+    tsl::hopscotch_map<K, V, fnv1a_hash, std::equal_to<K>, ::allocator< std::pair<K, V> >>;
+
+template<class K, class V> using tsl_hopscotch_pg_map_fnv1a =
+    tsl::hopscotch_pg_map<K, V, fnv1a_hash, std::equal_to<K>, ::allocator< std::pair<K, V> >>;
+
+#endif
+
+#ifdef HAVE_TSL_ROBIN
+
+template<class K, class V> using tsl_robin_map_fnv1a =
+    tsl::robin_map<K, V, fnv1a_hash, std::equal_to<K>, ::allocator< std::pair<K, V> >>;
+
+template<class K, class V> using tsl_robin_pg_map_fnv1a =
+    tsl::robin_pg_map<K, V, fnv1a_hash, std::equal_to<K>, ::allocator< std::pair<K, V> >>;
+
+#endif
+
 //
 
 int main()
@@ -383,6 +432,20 @@ int main()
 
 #endif
 
+#ifdef HAVE_TSL_HOPSCOTCH
+
+    test<tsl_hopscotch_map>( "tsl::hopscotch_map" );
+    test<tsl_hopscotch_pg_map>( "tsl::hopscotch_pg_map" );
+
+#endif
+
+#ifdef HAVE_TSL_ROBIN
+
+    test<tsl_robin_map>( "tsl::robin_map" );
+    test<tsl_robin_pg_map>( "tsl::robin_pg_map" );
+
+#endif
+
 #endif
 
     test<std_unordered_map_fnv1a>( "std::unordered_map, FNV-1a" );
@@ -394,13 +457,27 @@ int main()
     test<absl_node_hash_map_fnv1a>( "absl::node_hash_map, FNV-1a" );
     test<absl_flat_hash_map_fnv1a>( "absl::flat_hash_map, FNV-1a" );
 
+#endif
+
+#ifdef HAVE_TSL_HOPSCOTCH
+
+    test<tsl_hopscotch_map_fnv1a>( "tsl::hopscotch_map, FNV-1a" );
+    test<tsl_hopscotch_pg_map_fnv1a>( "tsl::hopscotch_pg_map, FNV-1a" );
+
+#endif
+
+#ifdef HAVE_TSL_ROBIN
+
+    test<tsl_robin_map_fnv1a>( "tsl::robin_map, FNV-1a" );
+    test<tsl_robin_pg_map_fnv1a>( "tsl::robin_pg_map, FNV-1a" );
+
 #endif
 
     std::cout << "---\n\n";
 
     for( auto const& x: times )
     {
-        std::cout << std::setw( 30 ) << ( x.label_ + ": " ) << std::setw( 5 ) << x.time_ << " ms, " << std::setw( 9 ) << x.bytes_ << " bytes in " << x.count_ << " allocations\n";
+        std::cout << std::setw( 31 ) << ( x.label_ + ": " ) << std::setw( 5 ) << x.time_ << " ms, " << std::setw( 9 ) << x.bytes_ << " bytes in " << x.count_ << " allocations\n";
     }
 }
 

benchmark/uint32.cpp

@@ -8,12 +8,19 @@
 #include <boost/multi_index_container.hpp>
 #include <boost/multi_index/hashed_index.hpp>
 #include <boost/multi_index/member.hpp>
+#include <boost/endian/conversion.hpp>
 #include <boost/core/detail/splitmix64.hpp>
 #include <boost/config.hpp>
 #ifdef HAVE_ABSEIL
 # include "absl/container/node_hash_map.h"
 # include "absl/container/flat_hash_map.h"
 #endif
+#ifdef HAVE_TSL_HOPSCOTCH
+# include "tsl/hopscotch_map.h"
+#endif
+#ifdef HAVE_TSL_ROBIN
+# include "tsl/robin_map.h"
+#endif
 #include <unordered_map>
 #include <vector>
 #include <memory>
@@ -62,7 +69,7 @@ static void init_indices()
 
     for( unsigned i = 1; i <= N*2; ++i )
     {
-        indices3.push_back( (std::uint32_t)i << 11 );
+        indices3.push_back( boost::endian::endian_reverse( static_cast<std::uint32_t>( i ) ) );
     }
 }
 
@@ -87,7 +94,7 @@ template<class Map> BOOST_NOINLINE void test_insert( Map& map, std::chrono::stea
         map.insert( { indices3[ i ], i } );
     }
 
-    print_time( t1, "Consecutive shifted insert",  0, map.size() );
+    print_time( t1, "Consecutive reversed insert",  0, map.size() );
 
     std::cout << std::endl;
 }
@@ -133,7 +140,7 @@ template<class Map> BOOST_NOINLINE void test_lookup( Map& map, std::chrono::stea
         }
     }
 
-    print_time( t1, "Consecutive shifted lookup",  s, map.size() );
+    print_time( t1, "Consecutive reversed lookup",  s, map.size() );
 
     std::cout << std::endl;
 }
@@ -146,7 +153,14 @@ template<class Map> BOOST_NOINLINE void test_iteration( Map& map, std::chrono::s
     {
         if( it->second & 1 )
         {
-            map.erase( it++ );
+            if constexpr( std::is_void_v< decltype( map.erase( it ) ) > )
+            {
+                map.erase( it++ );
+            }
+            else
+            {
+                it = map.erase( it );
+            }
         }
         else
         {
@@ -168,13 +182,9 @@ template<class Map> BOOST_NOINLINE void test_erase( Map& map, std::chrono::stead
 
     print_time( t1, "Consecutive erase",  0, map.size() );
 
+    for( unsigned i = 1; i <= N; ++i )
     {
-        boost::detail::splitmix64 rng;
-
-        for( unsigned i = 1; i <= N; ++i )
-        {
-            map.erase( indices2[ i ] );
-        }
+        map.erase( indices2[ i ] );
     }
 
     print_time( t1, "Random erase",  0, map.size() );
@@ -184,7 +194,7 @@ template<class Map> BOOST_NOINLINE void test_erase( Map& map, std::chrono::stead
         map.erase( indices3[ i ] );
     }
 
-    print_time( t1, "Consecutive shifted erase",  0, map.size() );
+    print_time( t1, "Consecutive reversed erase",  0, map.size() );
 
     std::cout << std::endl;
 }
@@ -311,6 +321,26 @@ template<class K, class V> using absl_flat_hash_map =
 
 #endif
 
+#ifdef HAVE_TSL_HOPSCOTCH
+
+template<class K, class V> using tsl_hopscotch_map =
+    tsl::hopscotch_map<K, V, std::hash<K>, std::equal_to<K>, ::allocator< std::pair<K, V> >>;
+
+template<class K, class V> using tsl_hopscotch_pg_map =
+    tsl::hopscotch_pg_map<K, V, std::hash<K>, std::equal_to<K>, ::allocator< std::pair<K, V> >>;
+
+#endif
+
+#ifdef HAVE_TSL_ROBIN
+
+template<class K, class V> using tsl_robin_map =
+    tsl::robin_map<K, V, std::hash<K>, std::equal_to<K>, ::allocator< std::pair<K, V> >>;
+
+template<class K, class V> using tsl_robin_pg_map =
+    tsl::robin_pg_map<K, V, std::hash<K>, std::equal_to<K>, ::allocator< std::pair<K, V> >>;
+
+#endif
+
 int main()
 {
     init_indices();
@@ -324,6 +354,20 @@ int main()
     test<absl_node_hash_map>( "absl::node_hash_map" );
     test<absl_flat_hash_map>( "absl::flat_hash_map" );
 
+#endif
+
+#ifdef HAVE_TSL_HOPSCOTCH
+
+    test<tsl_hopscotch_map>( "tsl::hopscotch_map" );
+    test<tsl_hopscotch_pg_map>( "tsl::hopscotch_pg_map" );
+
+#endif
+
+#ifdef HAVE_TSL_ROBIN
+
+    test<tsl_robin_map>( "tsl::robin_map" );
+    test<tsl_robin_pg_map>( "tsl::robin_pg_map" );
+
 #endif
 
     std::cout << "---\n\n";

benchmark/uint64.cpp

@@ -8,12 +8,19 @@
 #include <boost/multi_index_container.hpp>
 #include <boost/multi_index/hashed_index.hpp>
 #include <boost/multi_index/member.hpp>
+#include <boost/endian/conversion.hpp>
 #include <boost/core/detail/splitmix64.hpp>
 #include <boost/config.hpp>
 #ifdef HAVE_ABSEIL
 # include "absl/container/node_hash_map.h"
 # include "absl/container/flat_hash_map.h"
 #endif
+#ifdef HAVE_TSL_HOPSCOTCH
+# include "tsl/hopscotch_map.h"
+#endif
+#ifdef HAVE_TSL_ROBIN
+# include "tsl/robin_map.h"
+#endif
 #include <unordered_map>
 #include <vector>
 #include <memory>
@@ -62,7 +69,7 @@ static void init_indices()
 
     for( unsigned i = 1; i <= N*2; ++i )
     {
-        indices3.push_back( (std::uint64_t)i << 40 );
+        indices3.push_back( boost::endian::endian_reverse( static_cast<std::uint64_t>( i ) ) );
     }
 }
 
@@ -87,7 +94,7 @@ template<class Map> BOOST_NOINLINE void test_insert( Map& map, std::chrono::stea
         map.insert( { indices3[ i ], i } );
     }
 
-    print_time( t1, "Consecutive shifted insert",  0, map.size() );
+    print_time( t1, "Consecutive reversed insert",  0, map.size() );
 
     std::cout << std::endl;
 }
@@ -133,7 +140,7 @@ template<class Map> BOOST_NOINLINE void test_lookup( Map& map, std::chrono::stea
         }
     }
 
-    print_time( t1, "Consecutive shifted lookup",  s, map.size() );
+    print_time( t1, "Consecutive reversed lookup",  s, map.size() );
 
     std::cout << std::endl;
 }
@@ -146,7 +153,14 @@ template<class Map> BOOST_NOINLINE void test_iteration( Map& map, std::chrono::s
     {
         if( it->second & 1 )
         {
-            map.erase( it++ );
+            if constexpr( std::is_void_v< decltype( map.erase( it ) ) > )
+            {
+                map.erase( it++ );
+            }
+            else
+            {
+                it = map.erase( it );
+            }
         }
         else
         {
@@ -168,13 +182,9 @@ template<class Map> BOOST_NOINLINE void test_erase( Map& map, std::chrono::stead
 
     print_time( t1, "Consecutive erase",  0, map.size() );
 
+    for( unsigned i = 1; i <= N; ++i )
     {
-        boost::detail::splitmix64 rng;
-
-        for( unsigned i = 1; i <= N; ++i )
-        {
-            map.erase( indices2[ i ] );
-        }
+        map.erase( indices2[ i ] );
     }
 
     print_time( t1, "Random erase",  0, map.size() );
@@ -184,7 +194,7 @@ template<class Map> BOOST_NOINLINE void test_erase( Map& map, std::chrono::stead
         map.erase( indices3[ i ] );
     }
 
-    print_time( t1, "Consecutive shifted erase",  0, map.size() );
+    print_time( t1, "Consecutive reversed erase",  0, map.size() );
 
     std::cout << std::endl;
 }
@@ -311,6 +321,26 @@ template<class K, class V> using absl_flat_hash_map =
 
 #endif
 
+#ifdef HAVE_TSL_HOPSCOTCH
+
+template<class K, class V> using tsl_hopscotch_map =
+    tsl::hopscotch_map<K, V, std::hash<K>, std::equal_to<K>, ::allocator< std::pair<K, V> >>;
+
+template<class K, class V> using tsl_hopscotch_pg_map =
+    tsl::hopscotch_pg_map<K, V, std::hash<K>, std::equal_to<K>, ::allocator< std::pair<K, V> >>;
+
+#endif
+
+#ifdef HAVE_TSL_ROBIN
+
+template<class K, class V> using tsl_robin_map =
+    tsl::robin_map<K, V, std::hash<K>, std::equal_to<K>, ::allocator< std::pair<K, V> >>;
+
+template<class K, class V> using tsl_robin_pg_map =
+    tsl::robin_pg_map<K, V, std::hash<K>, std::equal_to<K>, ::allocator< std::pair<K, V> >>;
+
+#endif
+
 int main()
 {
     init_indices();
@@ -324,6 +354,20 @@ int main()
     test<absl_node_hash_map>( "absl::node_hash_map" );
     test<absl_flat_hash_map>( "absl::flat_hash_map" );
 
+#endif
+
+#ifdef HAVE_TSL_HOPSCOTCH
+
+    test<tsl_hopscotch_map>( "tsl::hopscotch_map" );
+    test<tsl_hopscotch_pg_map>( "tsl::hopscotch_pg_map" );
+
+#endif
+
+#ifdef HAVE_TSL_ROBIN
+
+    test<tsl_robin_map>( "tsl::robin_map" );
+    test<tsl_robin_pg_map>( "tsl::robin_pg_map" );
+
 #endif
 
     std::cout << "---\n\n";

ci/download-boost-snapshot.py

@@ -1,66 +0,0 @@
-#!/usr/bin/env python
-
-import urllib, os, os.path, sys, json, tarfile, zipfile, tempfile
-
-def download(snapshot):
-    if snapshot == 'stable':
-        # TODO: Default version/filename if not available?
-        downloads = [
-            "https://sourceforge.net/projects/boost/files/boost/%s/%s.tar.bz2/download" %
-                (os.environ['BOOST_VERSION'], os.environ['BOOST_FILENAME'])]
-    else:
-        json_response = urllib.urlopen('https://api.bintray.com/packages/boostorg/%s/snapshot/files' % (snapshot))
-        x = json.load(json_response)
-
-        extension_priorities = { '.bz2': 2, '.gz': 1, '.zip': 0 }
-        file_list = []
-        version_dates = {}
-        for file in x:
-            file_extension = os.path.splitext(file['path'])[1]
-            if (file_extension in extension_priorities):
-                file['priority'] = extension_priorities[file_extension]
-                file_list.append(file)
-                if not file['version'] in version_dates or file['created'] < version_dates[file['version']]:
-                    version_dates[file['version']] = file['created']
-        file_list.sort(key=lambda x: (version_dates[x['version']], x['priority']), reverse=True)
-        downloads = ['http://dl.bintray.com/boostorg/%s/%s' % (snapshot, file['path']) for file in file_list]
-
-    filename = ''
-    for download_url in downloads:
-        try:
-            print "Downloading: " + download_url
-            (filename, headers) = urllib.urlretrieve(download_url)
-
-            print "Extracting: " + filename
-            dir = tempfile.mkdtemp()
-            extract(filename, dir)
-            os.remove(filename)
-            files = os.listdir(dir)
-            assert(len(files) == 1)
-            os.rename(os.path.join(dir, files[0]), 'boost')
-            return
-        except IOError:
-            print "Error opening URL: " + download_url
-
-def extract(filename, path = '.'):
-    if (filename.endswith(".gz")):
-        tar = tarfile.open(filename, "r:gz")
-        tar.extractall(path)
-        tar.close
-    elif (filename.endswith(".bz2")):
-        tar = tarfile.open(filename, "r:bz2")
-        tar.extractall(path)
-        tar.close
-    elif (filename.endswith(".zip")):
-        zip = zipfile.ZipFile(filename, "r")
-        zip.extractall(path)
-        zip.close
-    else:
-        assert False
-
-if len(sys.argv) == 1:
-    download('stable')
-elif len(sys.argv) == 2:
-    download(sys.argv[1])
-else:
-    print "Usage: %s [stable|branch-name]" % (sys.argv[0])

doc/preview.md

@@ -0,0 +1,47 @@
+# Building Boost from the Tip of Develop
+
+To build Boost from the tip of the develop branch without cloning the entire 
+history, use the command below:
+
+Linux:
+```bash
+cwd=$(pwd) \
+  && cd ~ \
+  && git clone -b develop --depth 1 --recurse-submodules --shallow-submodules --jobs 8 https://github.com/boostorg/boost.git boost-develop-beta \
+  && cd boost-develop-beta \
+  && ./bootstrap.sh \
+  && ./b2 install --prefix=boost-install cxxstd=17 \
+  && echo "Boost successfully installed into $(realpath boost-install)!
+  Add this to your CMake toolchain file.
+  list(APPEND CMAKE_PREFIX_PATH $(realpath boost-install))
+  " \
+  && cd $cwd
+```
+
+Windows (using plain Command Prompt):
+```bat
+cmd /v
+set cwd=%cd% ^
+  && cd %homepath% ^
+  && git clone -b develop --depth 1 --recurse-submodules --shallow-submodules --jobs 8 https://github.com/boostorg/boost.git boost-develop-beta ^
+  && cd boost-develop-beta ^
+  && bootstrap.bat ^
+  && b2 install --prefix=boost-install cxxstd=17 address-model=64 ^
+  && echo Boost successfully installed into !cd!\boost-install! ^
+  && echo Add this to your CMake toolchain file. ^
+  && echo list(APPEND CMAKE_PREFIX_PATH !cd:\=/!/boost-install) ^
+  && cd !cwd! ^
+  && exit
+```
+
+Note: you can build Boost with a specific compiler by setting the toolset in 
+the `./b2` command above. To build with clang, specify `toolset=clang`; to build
+with a specific version of gcc, clang or msvc, specify e.g. `toolset=gcc-12` for GCC 
+12, `clang-14` for Clang 14, `msvc-14.3` for MSVC 14.3. The value of `cxxstd` 
+can also be set to other values such as 11 for C++11, 14 for C++14, etc.
+
+For more info on what's possible, check out this link on b2:
+https://www.boost.org/doc/libs/develop/tools/build/doc/html/index.html#bbv2.overview.builtins.features
+
+This should hopefully cover the two most common cases of building a dependency, 
+setting the compiler and C++ standard used.

doc/roadmap.md

@@ -0,0 +1,188 @@
+# Refactoring Roadmap
+
+[Proof of concept](https://github.com/joaquintides/fca_unordered) implementation for a fast closed-addressing implementation.
+
+## Plan of Refactoring
+
+* remove `ptr_node` and `ptr_bucket`
+* see if the code can survive a lack of the `extra_node` or maybe we hard-code it in
+* implement bucket groups as they are in `fca` but don't use them directly yet, add alongside the `buckets_` data member in `struct table`
+* try to remove `bucket_info_` from the node structure (breaks all call-sites that use `get_bucket()` and dependents)
+* make sure `fca` can successfully handle multi-variants at this stage + supports mutable iterators for `map`/`multimap`
+* do a hard-break:
+    * update code to no longer use one single linked list across all buckets (each bucket contains its own unique list)
+    * integrate the `bucket_group<Node>` structure into the `table` (update iterator call-sites to include `bucket_iterator`s)
+
+Blockers:
+* how to handle `multi` variants with new `fca` prototype
+
+## Implementation Differences
+
+### Unordered
+
+### Node Type
+
+Bullet Points:
+* reify node type into a single one
+* come up with implementation for multi- variants
+* code that touches `get_bucket()` and `*_in_group()` member functions may need updating
+
+There are two node types in Unordered, `struct node` and `struct ptr_node`, and the node type is selected conditionally based on the Allocator's pointer type:
+```c++
+template <typename A, typename T, typename NodePtr, typename BucketPtr>
+struct pick_node2
+{
+  typedef boost::unordered::detail::node<A, T> node;
+  // ...
+};
+
+template <typename A, typename T>
+struct pick_node2<A, T, boost::unordered::detail::ptr_node<T>*,
+  boost::unordered::detail::ptr_bucket*>
+{ 
+  typedef boost::unordered::detail::ptr_node<T> node;
+  // ...
+};
+
+template <typename A, typename T> struct pick_node
+{
+  typedef typename boost::remove_const<T>::type nonconst;
+
+  typedef boost::unordered::detail::allocator_traits<
+    typename boost::unordered::detail::rebind_wrap<A,
+      boost::unordered::detail::ptr_node<nonconst> >::type>
+    tentative_node_traits;
+
+  typedef boost::unordered::detail::allocator_traits<
+    typename boost::unordered::detail::rebind_wrap<A,
+      boost::unordered::detail::ptr_bucket>::type>
+    tentative_bucket_traits;
+
+  typedef pick_node2<A, nonconst, typename tentative_node_traits::pointer,
+    typename tentative_bucket_traits::pointer>
+    pick;
+
+  typedef typename pick::node node;
+  typedef typename pick::bucket bucket;
+  typedef typename pick::link_pointer link_pointer;
+};
+```
+
+The node types are identical in terms of interface and the only difference is that `node` is chosen when the Allocator uses fancy pointers and `ptr_node` is chosen when the Allocator's pointer type is `T*`.
+
+Nodes in Unorderd store `bucket_info_`:
+```cpp
+template <typename A, typename T>
+struct node : boost::unordered::detail::value_base<T>
+{
+  link_pointer next_;
+  std::size_t bucket_info_;
+  node() : next_(), bucket_info_(0) {}
+  // ...
+};
+```
+
+`bucket_info_` maps each node back to its corresponding bucket via the member function:
+```cpp
+std::size_t get_bucket() const
+{
+  return bucket_info_ & ((std::size_t)-1 >> 1);
+}
+```
+
+`bucket_info_` is also used to demarcate the start of equivalent nodes in the containers via:
+```cpp
+// Note that nodes start out as the first in their group, as `bucket_info_` defaults to 0.
+std::size_t is_first_in_group() const
+{ return !(bucket_info_ & ~((std::size_t)-1 >> 1)); }
+
+void set_first_in_group()
+{ bucket_info_ = bucket_info_ & ((std::size_t)-1 >> 1); }
+
+void reset_first_in_group()
+{ bucket_info_ = bucket_info_ | ~((std::size_t)-1 >> 1); }
+```
+
+A goal of refactoring is to simply have one node type:
+```cpp
+template<class T>
+struct node {
+  node *next;
+  T    value;
+};
+```
+that is used unconditionally. This also requires updating the code that touches the `bucket_info_` along with the code that that touches the `*_in_group()` member functions.
+
+### Bucket Type
+
+Bullet points:
+* reify bucket structure into a single one
+* figure out how to add `bucket_group`s to the table struct
+
+Buckets are similar to nodes in that there are two variations: `template<class NodePointer> struct bucket` and `struct ptr_bucket`.
+
+The buckets exist to contain a pointer to a node, however they contain an `enum { extra_node = true };` or `enum { extra_node = false }` to determine whether or not the code should explicitly allocate a default constructed node whose address assigned as the dummy node at the end of the bucket array.
+
+`extra_node` is used in the creation and deletion of the bucket array but it is not inherently clear what its intended purpose is.
+
+### Iterators
+
+Iterators are currently templated on the type of Node they store. Because `fca` constructs iterators with two arguments, all the call-sites that instantiate iterators will need to be updated but this a straight-forward mechanical change.
+
+Iterators are selected, as of now, via the `detail::map` and `detail::set` class templates.
+
+For example, for `unordered_map`, `iterator` is defined as:
+```cpp
+typedef boost::unordered::detail::map<A, K, T, H, P> types;
+typedef typename types::table table;
+typedef typename table::iterator iterator;
+```
+
+The iterator is a member typedef of the `table` which is `types::table`. Examining `types` (aka `detail::map<...>`), we see:
+```cpp
+template <typename A, typename K, typename M, typename H, typename P>
+struct map {
+  // ...
+  typedef boost::unordered::detail::table<types> table;
+  // ...
+};
+```
+
+Examining the `detail::table<types>` struct, we see:
+```cpp
+template <typename Types>
+struct table {
+  // ...
+  typedef typename Types::iterator iterator;
+  // ...
+}
+```
+
+Collapsing all of this, we see that our iterator types are defined here:
+```cpp
+template <typename A, typename K, typename M, typename H, typename P>
+struct map
+{
+  // ...
+  typedef boost::unordered::detail::pick_node<A, value_type> pick;
+  typedef typename pick::node node;
+
+  typedef boost::unordered::iterator_detail::iterator<node> iterator;
+  typedef boost::unordered::iterator_detail::c_iterator<node> c_iterator;
+  typedef boost::unordered::iterator_detail::l_iterator<node> l_iterator;
+  typedef boost::unordered::iterator_detail::cl_iterator<node>
+    cl_iterator;
+  // ...
+};
+```
+
+This is similarly designed for `detail::set`:
+```cpp
+typedef boost::unordered::iterator_detail::c_iterator<node> iterator;
+typedef boost::unordered::iterator_detail::c_iterator<node> c_iterator;
+typedef boost::unordered::iterator_detail::cl_iterator<node> l_iterator;
+typedef boost::unordered::iterator_detail::cl_iterator<node>
+  cl_iterator;
+```
+
+The only difference here is that `set::iterator` is always a `c_iterator`, a `const_iterator` type.

doc/unordered.adoc

@@ -12,6 +12,7 @@
 
 include::unordered/intro.adoc[]
 include::unordered/buckets.adoc[]
+include::unordered/benchmarks.adoc[]
 include::unordered/hash_equality.adoc[]
 include::unordered/comparison.adoc[]
 include::unordered/compliance.adoc[]

doc/unordered/benchmarks.adoc

@@ -0,0 +1,277 @@
+[#benchmarks]
+:idprefix: benchmarks_
+:imagesdir: ../diagrams
+
+= Benchmarks
+
+All benchmarks were created using `unordered_set<unsigned int>` (non-duplicate) and `unordered_multiset<unsigned int>` (duplicate). The source code can be https://github.com/joaquintides/boost_unordered_benchmark[found here].
+
+The insertion benchmarks insert `n` random values, where `n` is between 10,000 and 3 million. For the duplicated benchmarks, the same random values are repeated an average of 5 times.
+
+The erasure benchmarks erase all `n` elements randomly until the container is empty.
+
+The successful lookup benchmarks are done by looking up all `n` values, in the their original insertion order.
+
+The unsuccessful lookup benchmarks use `n` randomly generated integers but using a different seed value.
+
+== GCC 11 + libstdc++-v3
+
+=== Insertion
+
+[caption=]
+[cols="3*^.^a", frame=all, grid=all]
+|===
+
+|image::benchmarks/gcc/running insertion.xlsx.practice.png[width=250,link=../diagrams/benchmarks/gcc/running insertion.xlsx.practice.png,window=_blank]
+|image::benchmarks/gcc/running%20insertion.xlsx.practice non-unique.png[width=250,link=../diagrams/benchmarks/gcc/running%20insertion.xlsx.practice non-unique.png,window=_blank]
+|image::benchmarks/gcc/running%20insertion.xlsx.practice non-unique 5.png[width=250,link=../diagrams/benchmarks/gcc/running%20insertion.xlsx.practice non-unique 5.png,window=_blank]
+
+h|non-duplicate elements 
+h|duplicate elements 
+h|duplicate elements +
+max load factor 5
+|===
+
+[caption=]
+[cols="3*^.^a", frame=all, grid=all]
+|===
+
+|image::benchmarks/gcc/running%20insertion.xlsx.practice norehash.png[width=250,link=../diagrams/benchmarks/gcc/running%20insertion.xlsx.practice norehash.png,window=_blank]
+|image::benchmarks/gcc/running%20insertion.xlsx.practice norehash non-unique.png[width=250,link=../diagrams/benchmarks/gcc/running%20insertion.xlsx.practice norehash non-unique.png,window=_blank]
+|image::benchmarks/gcc/running%20insertion.xlsx.practice norehash non-unique 5.png[width=250,link=../diagrams/benchmarks/gcc/running%20insertion.xlsx.practice norehash non-unique 5.png,window=_blank]
+
+h|non-duplicate elements, +
+prior `reserve`
+h|duplicate elements, +
+prior `reserve` 
+h|duplicate elements, +
+max load factor 5, +
+prior `reserve`
+
+|===
+
+=== Erasure
+
+[caption=]
+[cols="3*^.^a", frame=all, grid=all]
+|===
+
+|image::benchmarks/gcc/scattered%20erasure.xlsx.practice.png[width=250,link=../diagrams/benchmarks/gcc/scattered%20erasure.xlsx.practice.png,window=_blank]
+|image::benchmarks/gcc/scattered%20erasure.xlsx.practice non-unique.png[width=250,link=../diagrams/benchmarks/gcc/scattered%20erasure.xlsx.practice non-unique.png,window=_blank]
+|image::benchmarks/gcc/scattered%20erasure.xlsx.practice non-unique 5.png[width=250,link=../diagrams/benchmarks/gcc/scattered%20erasure.xlsx.practice non-unique 5.png,window=_blank]
+
+h|non-duplicate elements 
+h|duplicate elements 
+h|duplicate elements +
+max load factor 5
+|===
+
+=== Successful Lookup
+
+[caption=]
+[cols="3*^.^a", frame=all, grid=all]
+|===
+
+|image::benchmarks/gcc/scattered%20successful%20looukp.xlsx.practice.png[width=250,window=_blank,link=../diagrams/benchmarks/gcc/scattered%20successful%20looukp.xlsx.practice.png]
+|image::benchmarks/gcc/scattered%20successful%20looukp.xlsx.practice non-unique.png[width=250,window=_blank,link=../diagrams/benchmarks/gcc/scattered%20successful%20looukp.xlsx.practice non-unique.png]
+|image::benchmarks/gcc/scattered%20successful%20looukp.xlsx.practice non-unique 5.png[width=250,window=_blank,link=../diagrams/benchmarks/gcc/scattered%20successful%20looukp.xlsx.practice non-unique 5.png]
+
+h|non-duplicate elements
+h|duplicate elements
+h|duplicate elements, +
+max load factor 5
+
+|===
+
+=== Unsuccessful lookup
+
+[caption=]
+[cols="3*^.^a", frame=all, grid=all]
+|===
+
+|image::benchmarks/gcc/scattered%20unsuccessful%20looukp.xlsx.practice.png[width=250,window=_blank,link=../diagrams/benchmarks/gcc/scattered%20unsuccessful%20looukp.xlsx.practice.png]
+|image::benchmarks/gcc/scattered%20unsuccessful%20looukp.xlsx.practice non-unique.png[width=250,window=_blank,link=../diagrams/benchmarks/gcc/scattered%20unsuccessful%20looukp.xlsx.practice non-unique.png]
+|image::benchmarks/gcc/scattered%20unsuccessful%20looukp.xlsx.practice non-unique 5.png[width=250,window=_blank,link=../diagrams/benchmarks/gcc/scattered%20unsuccessful%20looukp.xlsx.practice non-unique 5.png]
+
+h|non-duplicate elements
+h|duplicate elements
+h|duplicate elements, +
+max load factor 5
+
+|===
+
+== Clang 12 + libc++
+
+=== Insertion
+
+[caption=]
+[cols="3*^.^a", frame=all, grid=all]
+|===
+
+|image::benchmarks/clang_libcpp/running%20insertion.xlsx.practice.png[width=250, window=_blank,link=../diagrams/benchmarks/clang_libcpp/running%20insertion.xlsx.practice.png]
+|image::benchmarks/clang_libcpp/running%20insertion.xlsx.practice non-unique.png[width=250, window=_blank,link=../diagrams/benchmarks/clang_libcpp/running%20insertion.xlsx.practice non-unique.png]
+|image::benchmarks/clang_libcpp/running%20insertion.xlsx.practice non-unique 5.png[width=250, window=_blank,link=../diagrams/benchmarks/clang_libcpp/running%20insertion.xlsx.practice non-unique 5.png]
+
+h|non-duplicate elements
+h|duplicate elements
+h|duplicate elements, +
+max load factor 5
+
+|===
+
+[caption=]
+[cols="3*^.^a", frame=all, grid=all]
+|===
+
+|image::benchmarks/clang_libcpp/running%20insertion.xlsx.practice norehash.png[width=250,window=_blank,link=../diagrams/benchmarks/clang_libcpp/running%20insertion.xlsx.practice norehash.png]
+|image::benchmarks/clang_libcpp/running%20insertion.xlsx.practice norehash non-unique.png[width=250,window=_blank,link=../diagrams/benchmarks/clang_libcpp/running%20insertion.xlsx.practice norehash non-unique.png]
+|image::benchmarks/clang_libcpp/running%20insertion.xlsx.practice norehash non-unique 5.png[width=250,window=_blank,link=../diagrams/benchmarks/clang_libcpp/running%20insertion.xlsx.practice norehash non-unique 5.png]
+
+h|non-duplicate elements, +
+prior `reserve`
+h|duplicate elements, +
+prior `reserve`
+h|duplicate elements, +
+max load factor 5, +
+prior `reserve`
+
+|===
+
+=== Erasure
+
+[caption=]
+[cols="3*^.^a", frame=all, grid=all]
+|===
+
+|image::benchmarks/clang_libcpp/scattered%20erasure.xlsx.practice.png[width=250,window=_blank,link=../diagrams/benchmarks/clang_libcpp/scattered%20erasure.xlsx.practice.png]
+|image::benchmarks/clang_libcpp/scattered%20erasure.xlsx.practice non-unique.png[width=250,window=_blank,link=../diagrams/benchmarks/clang_libcpp/scattered%20erasure.xlsx.practice non-unique.png]
+|image::benchmarks/clang_libcpp/scattered%20erasure.xlsx.practice non-unique 5.png[width=250,window=_blank,link=../diagrams/benchmarks/clang_libcpp/scattered%20erasure.xlsx.practice non-unique 5.png]
+
+h|non-duplicate elements
+h|duplicate elements
+h|duplicate elements, +
+max load factor 5
+
+|===
+
+=== Successful lookup
+
+[caption=]
+[cols="3*^.^a", frame=all, grid=all]
+|===
+
+|image::benchmarks/clang_libcpp/scattered%20successful%20looukp.xlsx.practice.png[width=250,window=_blank,link=../diagrams/benchmarks/clang_libcpp/scattered%20successful%20looukp.xlsx.practice.png]
+|image::benchmarks/clang_libcpp/scattered%20successful%20looukp.xlsx.practice non-unique.png[width=250,window=_blank,link=../diagrams/benchmarks/clang_libcpp/scattered%20successful%20looukp.xlsx.practice non-unique.png]
+|image::benchmarks/clang_libcpp/scattered%20successful%20looukp.xlsx.practice non-unique 5.png[width=250,window=_blank,link=../diagrams/benchmarks/clang_libcpp/scattered%20successful%20looukp.xlsx.practice non-unique 5.png]
+
+h|non-duplicate elements
+h|duplicate elements
+h|duplicate elements, +
+max load factor 5
+
+|===
+
+=== Unsuccessful lookup
+
+[caption=]
+[cols="3*^.^a", frame=all, grid=all]
+|===
+
+|image::benchmarks/clang_libcpp/scattered%20unsuccessful%20looukp.xlsx.practice.png[width=250,window=_blank,link=../diagrams/benchmarks/clang_libcpp/scattered%20unsuccessful%20looukp.xlsx.practice.png]
+|image::benchmarks/clang_libcpp/scattered%20unsuccessful%20looukp.xlsx.practice non-unique.png[width=250,window=_blank,link=../diagrams/benchmarks/clang_libcpp/scattered%20unsuccessful%20looukp.xlsx.practice non-unique.png]
+|image::benchmarks/clang_libcpp/scattered%20unsuccessful%20looukp.xlsx.practice non-unique 5.png[width=250,window=_blank,link=../diagrams/benchmarks/clang_libcpp/scattered%20unsuccessful%20looukp.xlsx.practice non-unique 5.png]
+
+h|non-duplicate elements
+h|duplicate elements
+h|duplicate elements, +
+max load factor 5
+
+|===
+
+== Visual Studio 2019 + Dinkumware
+
+=== Insertion
+
+[caption=]
+[cols="3*^.^a", frame=all, grid=all]
+|===
+
+|image::benchmarks/vs/running%20insertion.xlsx.practice.png[width=250,window=_blank,link=../diagrams/benchmarks/vs/running%20insertion.xlsx.practice.png]
+|image::benchmarks/vs/running%20insertion.xlsx.practice non-unique.png[width=250,window=_blank,link=../diagrams/benchmarks/vs/running%20insertion.xlsx.practice non-unique.png]
+|image::benchmarks/vs/running%20insertion.xlsx.practice non-unique 5.png[width=250,window=_blank,link=../diagrams/benchmarks/vs/running%20insertion.xlsx.practice non-unique 5.png]
+
+h|non-duplicate elements
+h|duplicate elements
+h|duplicate elements, +
+max load factor 5
+
+|===
+
+[caption=]
+[cols="3*^.^a", frame=all, grid=all]
+|===
+
+|image::benchmarks/vs/running%20insertion.xlsx.practice norehash.png[width=250,window=_blank,link=../diagrams/benchmarks/vs/running%20insertion.xlsx.practice norehash.png]
+|image::benchmarks/vs/running%20insertion.xlsx.practice norehash non-unique.png[width=250,window=_blank,link=../diagrams/benchmarks/vs/running%20insertion.xlsx.practice norehash non-unique.png]
+|image::benchmarks/vs/running%20insertion.xlsx.practice norehash non-unique 5.png[width=250,window=_blank,link=../diagrams/benchmarks/vs/running%20insertion.xlsx.practice norehash non-unique 5.png]
+
+h|non-duplicate elements, +
+prior `reserve`
+h|duplicate elements, +
+prior `reserve`
+h|duplicate elements, +
+max load factor 5, +
+prior `reserve`
+
+|===
+
+=== Erasure
+
+[caption=]
+[cols="3*^.^a", frame=all, grid=all]
+|===
+
+|image::benchmarks/vs/scattered%20erasure.xlsx.practice.png[width=250,window=_blank,link=../diagrams/benchmarks/vs/scattered%20erasure.xlsx.practice.png]
+|image::benchmarks/vs/scattered%20erasure.xlsx.practice non-unique.png[width=250,window=_blank,link=../diagrams/benchmarks/vs/scattered%20erasure.xlsx.practice non-unique.png]
+|image::benchmarks/vs/scattered%20erasure.xlsx.practice non-unique 5.png[width=250,window=_blank,link=../diagrams/benchmarks/vs/scattered%20erasure.xlsx.practice non-unique 5.png]
+
+h|non-duplicate elements
+h|duplicate elements
+h|duplicate elements, +
+max load factor 5
+
+|===
+
+=== Successful lookup
+
+[caption=]
+[cols="3*^.^a", frame=all, grid=all]
+|===
+
+|image::benchmarks/vs/scattered%20successful%20looukp.xlsx.practice.png[width=250,window=_blank,link=../diagrams/benchmarks/vs/scattered%20successful%20looukp.xlsx.practice.png]
+|image::benchmarks/vs/scattered%20successful%20looukp.xlsx.practice non-unique.png[width=250,window=_blank,link=../diagrams/benchmarks/vs/scattered%20successful%20looukp.xlsx.practice non-unique.png]
+|image::benchmarks/vs/scattered%20successful%20looukp.xlsx.practice non-unique 5.png[width=250,window=_blank,link=../diagrams/benchmarks/vs/scattered%20successful%20looukp.xlsx.practice non-unique 5.png]
+
+h|non-duplicate elements
+h|duplicate elements
+h|duplicate elements, +
+max load factor 5
+
+|===
+
+=== Unsuccessful lookup
+
+[caption=]
+[cols="3*^.^a", frame=all, grid=all]
+|===
+
+|image::benchmarks/vs/scattered%20unsuccessful%20looukp.xlsx.practice.png[width=250,window=_blank,link=../diagrams/benchmarks/vs/scattered%20unsuccessful%20looukp.xlsx.practice.png]
+|image::benchmarks/vs/scattered%20unsuccessful%20looukp.xlsx.practice non-unique.png[width=250,window=_blank,link=../diagrams/benchmarks/vs/scattered%20unsuccessful%20looukp.xlsx.practice non-unique.png]
+|image::benchmarks/vs/scattered%20unsuccessful%20looukp.xlsx.practice non-unique 5.png[width=250,window=_blank,link=../diagrams/benchmarks/vs/scattered%20unsuccessful%20looukp.xlsx.practice non-unique 5.png]
+
+h|non-duplicate elements
+h|duplicate elements
+h|duplicate elements, +
+max load factor 5
+
+|===

doc/unordered/buckets.adoc

@@ -1,5 +1,6 @@
 [#buckets]
 :idprefix: buckets_
+:imagesdir: ../diagrams
 
 = The Data Structure
 
@@ -8,7 +9,7 @@ any number of elements. For example, the following diagram shows an <<unordered_
 `B`, `C`, `D` and `E` (this is just for illustration, containers will typically
 have more buckets).
 
-image::../diagrams/buckets.png[]
+image::buckets.png[]
 
 In order to decide which bucket to place an element in, the container applies
 the hash function, `Hash`, to the element's key (for `unordered_set` and
@@ -150,3 +151,60 @@ x.rehash(std::ceil(n / x.max_load_factor()))
 +
 See the <<unordered_map_rehash,reference for more details>> on the `rehash` function.
 
+== Fast Closed Addressing Implementation
+
+++++
+<style>
+  .imageblock > .title {
+    text-align: inherit;
+  }
+</style>
+++++
+
+Boost.Unordered sports one of the fastest implementations of closed addressing, also commonly known as https://en.wikipedia.org/wiki/Hash_table#Separate_chaining[separate chaining]. An example figure representing the data structure is below:
+
+[#img-bucket-groups,.text-center]
+.A simple bucket group approach
+image::bucket-groups.png[align=center]
+
+An array of "buckets" is allocated and each bucket in turn points to its own individual linked list. This makes meeting the standard requirements of bucket iteration straight-forward. Unfortunately, iteration of the entire container is often times slow using this layout as each bucket must be examined for occupancy, yielding a time complexity of `O(bucket_count() + size())` when the standard requires complexity to be `O(size())`.
+
+Canonical standard implementations will wind up looking like the diagram below:
+
+[.text-center]
+.The canonical standard approach
+image::singly-linked.png[align=center,link=../diagrams/singly-linked.png,window=_blank]
+
+It's worth noting that this approach is only used by pass:[libc++] and pass:[libstdc++]; the MSVC Dinkumware implementation uses a different one. A more detailed analysis of the standard containers can be found http://bannalia.blogspot.com/2013/10/implementation-of-c-unordered.html[here].
+
+This unusually laid out data structure is chosen to make iteration of the entire container efficient by inter-connecting all of the nodes into a singly-linked list. One might also notice that buckets point to the node _before_ the start of the bucket's elements. This is done so that removing elements from the list can be done efficiently without introducing the need for a doubly-linked list. Unfortunately, this data structure introduces a guaranteed extra indirection. For example, to access the first element of a bucket, something like this must be done:
+
+```c++
+auto const idx = get_bucket_idx(hash_function(key));
+node* p = buckets[idx]; // first load
+node* n = p->next; // second load
+if (n && is_in_bucket(n, idx)) {
+  value_type const& v = *n; // third load
+  // ...
+}
+```
+
+With a simple bucket group layout, this is all that must be done:
+```c++
+auto const idx = get_bucket_idx(hash_function(key));
+node* n = buckets[idx]; // first load
+if (n) {
+  value_type const& v = *n; // second load
+  // ...
+}
+```
+
+In practice, the extra indirection can have a dramatic performance impact to common operations such as `insert`, `find` and `erase`. But to keep iteration of the container fast, Boost.Unordered introduces a novel data structure, a "bucket group". A bucket group is a fixed-width view of a subsection of the buckets array. It contains a bitmask (a `std::size_t`) which it uses to track occupancy of buckets and contains two pointers so that it can form a doubly-linked list with non-empty groups. An example diagram is below:
+
+[#img-fca-layout]
+.The new layout used by Boost
+image::fca.png[align=center]
+
+Thus container-wide iteration is turned into traversing the non-empty bucket groups (an operation with constant time complexity) which reduces the time complexity back to `O(size())`. In total, a bucket group is only 4 words in size and it views `sizeof(std::size_t) * CHAR_BIT` buckets meaning that for all common implementations, there's only 4 bits of space overhead per bucket introduced by the bucket groups.
+
+For more information on implementation rationale, read the <<Implementation Rationale, corresponding section>>.

doc/unordered/changes.adoc

@@ -6,6 +6,13 @@
 :github-pr-url: https://github.com/boostorg/unordered/pull
 :cpp: C++
 
+== Release 1.80.0 - Major update
+
+* Refactor internal implementation to be dramatically faster
+* Allow `final` Hasher and KeyEqual objects
+* Update documentation, adding benchmark graphs and notes on the new internal 
+  data structures
+
 == Release 1.79.0
 
 * Improved {cpp}20 support:

doc/unordered/copyright.adoc

@@ -9,4 +9,6 @@ Copyright (C) 2003, 2004 Jeremy B. Maitin-Shepard
 
 Copyright (C) 2005-2008 Daniel James
 
+Copyright (C) 2022 Christian Mazakas
+
 Distributed under the Boost Software License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)

doc/unordered/rationale.adoc

@@ -66,3 +66,7 @@ by using `(h * m) >> (w - k)`, where `h` is the hash value, `m` is the golden
 ratio multiplied by `2^w`, `w` is the word size (32 or 64), and `2^k` is the
 number of buckets. This provides a good compromise between speed and
 distribution.
+
+Since release 1.80.0, prime numbers are chosen for the number of buckets in
+tandem with sophisticated modulo arithmetic. This removes the need for "mixing"
+the result of the user's hash function as was used for release 1.79.0.

doc/unordered/unordered_map.adoc

@@ -1566,7 +1566,9 @@ Effects:;; Changes the container's maximum load factor, using `z` as a hint.
 void rehash(size_type n);
 ```
 
-Changes the number of buckets so that there at least `n` buckets, and so that the load factor is less than the maximum load factor.
+Changes the number of buckets so that there are at least `n` buckets, and so that the load factor is less than or equal to the maximum load factor. When applicable, this will either grow or shrink the `bucket_count()` associated with the container.
+
+When `size() == 0`, `rehash(0)` will deallocate the underlying buckets array.
 
 Invalidates iterators, and changes the order of elements. Pointers and references to elements are not invalidated.
 
@@ -1580,6 +1582,10 @@ Throws:;; The function has no effect if an exception is thrown, unless it is thr
 void reserve(size_type n);
 ```
 
+Equivalent to `a.rehash(ceil(n / a.max_load_factor()))`, or `a.rehash(1)` if `n > 0` and `a.max_load_factor() == std::numeric_limits<float>::infinity()`.
+
+Similar to `rehash`, this function can be used to grow or shrink the number of buckets in the container.
+
 Invalidates iterators, and changes the order of elements. Pointers and references to elements are not invalidated.
 
 [horizontal]

doc/unordered/unordered_multimap.adoc

@@ -1345,7 +1345,9 @@ Effects:;; Changes the container's maximum load factor, using `z` as a hint.
 void rehash(size_type n);
 ```
 
-Changes the number of buckets so that there at least `n` buckets, and so that the load factor is less than the maximum load factor.
+Changes the number of buckets so that there are at least `n` buckets, and so that the load factor is less than or equal to the maximum load factor. When applicable, this will either grow or shrink the `bucket_count()` associated with the container.
+
+When `size() == 0`, `rehash(0)` will deallocate the underlying buckets array.
 
 Invalidates iterators, and changes the order of elements. Pointers and references to elements are not invalidated.
 
@@ -1359,6 +1361,10 @@ Throws:;; The function has no effect if an exception is thrown, unless it is thr
 void reserve(size_type n);
 ```
 
+Equivalent to `a.rehash(ceil(n / a.max_load_factor()))`, or `a.rehash(1)` if `n > 0` and `a.max_load_factor() == std::numeric_limits<float>::infinity()`.
+
+Similar to `rehash`, this function can be used to grow or shrink the number of buckets in the container.
+
 Invalidates iterators, and changes the order of elements. Pointers and references to elements are not invalidated.
 
 [horizontal]

doc/unordered/unordered_multiset.adoc

@@ -1306,7 +1306,9 @@ Effects:;; Changes the container's maximum load factor, using `z` as a hint.
 void rehash(size_type n);
 ```
 
-Changes the number of buckets so that there at least `n` buckets, and so that the load factor is less than the maximum load factor.
+Changes the number of buckets so that there are at least `n` buckets, and so that the load factor is less than or equal to the maximum load factor. When applicable, this will either grow or shrink the `bucket_count()` associated with the container.
+
+When `size() == 0`, `rehash(0)` will deallocate the underlying buckets array.
 
 Invalidates iterators, and changes the order of elements. Pointers and references to elements are not invalidated.
 
@@ -1320,11 +1322,16 @@ Throws:;; The function has no effect if an exception is thrown, unless it is thr
 void reserve(size_type n);
 ```
 
+Equivalent to `a.rehash(ceil(n / a.max_load_factor()))`, or `a.rehash(1)` if `n > 0` and `a.max_load_factor() == std::numeric_limits<float>::infinity()`.
+
+Similar to `rehash`, this function can be used to grow or shrink the number of buckets in the container.
+
 Invalidates iterators, and changes the order of elements. Pointers and references to elements are not invalidated.
 
 [horizontal]
 Throws:;; The function has no effect if an exception is thrown, unless it is thrown by the container's hash function or comparison function.
 
+
 ---
 
 === Equality Comparisons

doc/unordered/unordered_set.adoc

@@ -1329,7 +1329,9 @@ Effects:;; Changes the container's maximum load factor, using `z` as a hint.
 void rehash(size_type n);
 ```
 
-Changes the number of buckets so that there at least `n` buckets, and so that the load factor is less than the maximum load factor.
+Changes the number of buckets so that there are at least `n` buckets, and so that the load factor is less than or equal to the maximum load factor. When applicable, this will either grow or shrink the `bucket_count()` associated with the container.
+
+When `size() == 0`, `rehash(0)` will deallocate the underlying buckets array.
 
 Invalidates iterators, and changes the order of elements. Pointers and references to elements are not invalidated.
 
@@ -1343,11 +1345,16 @@ Throws:;; The function has no effect if an exception is thrown, unless it is thr
 void reserve(size_type n);
 ```
 
+Equivalent to `a.rehash(ceil(n / a.max_load_factor()))`, or `a.rehash(1)` if `n > 0` and `a.max_load_factor() == std::numeric_limits<float>::infinity()`.
+
+Similar to `rehash`, this function can be used to grow or shrink the number of buckets in the container.
+
 Invalidates iterators, and changes the order of elements. Pointers and references to elements are not invalidated.
 
 [horizontal]
 Throws:;; The function has no effect if an exception is thrown, unless it is thrown by the container's hash function or comparison function.
 
+
 === Equality Comparisons
 
 ==== operator==

include/boost/unordered/detail/fca.hpp

@@ -0,0 +1,849 @@
+// Copyright (C) 2022 Joaquin M Lopez Munoz.
+// Copyright (C) 2022 Christian Mazakas
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+
+#ifndef BOOST_UNORDERED_DETAIL_FCA_HPP
+#define BOOST_UNORDERED_DETAIL_FCA_HPP
+
+/*
+
+The general structure of the fast closed addressing implementation is that we
+use straight-forward separate chaining (i.e. each bucket contains its own linked
+list) and then improve iteration time by adding an array of "bucket groups".
+
+A bucket group is a constant-width view into a subsection of the buckets array,
+containing a bitmask that indicates which one of the buckets in the subsection
+contains a list of nodes. This allows the code to test N buckets for occupancy
+in a single operation. Additional speed can be found by inter-linking occupied
+bucket groups with one another in a doubly-linked list. To this end, large
+swathes of the bucket groups array no longer need to be iterated and have their
+bitmasks examined for occupancy.
+
+A bucket group iterator contains a pointer to a bucket group along with a
+pointer into the buckets array. The iterator's bucket pointer is guaranteed to
+point to a bucket within the bucket group's view of the array. To advance the
+iterator, we need to determine if we need to skip to the next bucket group or
+simply move to the next occupied bucket as denoted by the bitmask.
+
+To accomplish this, we perform something roughly equivalent to this:
+```
+bucket_iterator itb = ...
+bucket_pointer p = itb.p
+bucket_group_pointer pbg = itb.pbg
+
+offset = p - pbg->buckets
+// because we wish to see if the _next_ bit in the mask is occupied, we'll
+// generate a testing mask from the current offset + 1
+//
+testing_mask = reset_first_bits(offset + 1)
+n = ctz(pbg->bitmask & testing_mask)
+
+if (n < N) {
+  p = pbg->buckets + n
+} else {
+  pbg = pbg->next
+  p = pbg->buckets + ctz(pbg->bitmask)
+}
+```
+
+`reset_first_bits` yields an unsigned integral with the first n bits set to 0
+and then by counting the number of trailing zeroes when AND'd against the bucket
+group's bitmask, we can derive the offset into the buckets array. When the
+calculated offset is equal to N, we know we've reached the end of a bucket group
+and we can advance to the next one.
+
+This is a rough explanation for how iterator incrementation should work for a
+fixed width size of N as 3 for the bucket groups
+```
+N = 3
+p = buckets
+pbg->bitmask = 0b101
+pbg->buckets = buckets
+
+offset = p - pbg->buckets // => 0
+testing_mask = reset_first_bits(offset + 1) // reset_first_bits(1) => 0b110
+
+x = bitmask & testing_mask // => 0b101 & 0b110 => 0b100
+ctz(x) // ctz(0b100) => 2
+// 2 < 3
+=> p = pbg->buckets + 2
+
+// increment again...
+offset = p - pbg->buckets // => 2
+testing_mask = reset_first_bits(offset + 1) // reset_first_bits(3) => 0b000
+
+bitmask & testing_mask // 0b101 & 0b000 => 0b000
+ctz(0b000) => 3
+// 3 < 3 is false now
+pbg = pbg->next
+initial_offset = ctz(pbg->bitmask)
+p = pbg->buckets + initial_offset
+```
+
+For `size_` number of buckets, there are `1 + (size_ / N)` bucket groups where
+`N` is the width of a bucket group, determined at compile-time.
+
+We allocate space for `size_ + 1` buckets, using the last one as a dummy bucket
+which is kept permanently empty so it can act as a sentinel value in the
+implementation of `iterator end();`. We set the last bucket group to act as a
+sentinel.
+
+```
+num_groups = size_ / N + 1
+groups = allocate(num_groups)
+pbg = groups + (num_groups - 1)
+
+// not guaranteed to point to exactly N buckets
+pbg->buckets = buckets + N * (size_ / N)
+
+// this marks the true end of the bucket array
+buckets pbg->bitmask = set_bit(size_ % N)
+
+// links in on itself
+pbg->next = pbg->prev = pbg
+```
+
+To this end, we can devise a safe iteration scheme while also creating a useful
+sentinel to use as the end iterator.
+
+Otherwise, usage of the data structure is relatively straight-forward compared
+to normal separate chaining implementations.
+
+*/
+
+#include <boost/unordered/detail/prime_fmod.hpp>
+
+#include <boost/core/addressof.hpp>
+#include <boost/core/allocator_access.hpp>
+#include <boost/core/bit.hpp>
+#include <boost/core/empty_value.hpp>
+#include <boost/core/no_exceptions_support.hpp>
+#include <boost/cstdint.hpp>
+#include <boost/move/core.hpp>
+#include <boost/move/utility_core.hpp>
+#include <boost/swap.hpp>
+#include <boost/type_traits/aligned_storage.hpp>
+#include <boost/type_traits/alignment_of.hpp>
+
+#include <boost/config.hpp>
+
+#include <iterator>
+
+namespace boost {
+  namespace unordered {
+    namespace detail {
+
+      template <class ValueType, class VoidPtr> struct node
+      {
+        typedef ValueType value_type;
+        typedef typename boost::pointer_traits<VoidPtr>::template rebind_to<
+          node>::type node_pointer;
+
+        node_pointer next;
+        typename boost::aligned_storage<sizeof(value_type),
+          boost::alignment_of<value_type>::value>::type buf;
+
+        node() BOOST_NOEXCEPT : next(), buf() {}
+
+        value_type* value_ptr() BOOST_NOEXCEPT
+        {
+          return reinterpret_cast<value_type*>(buf.address());
+        }
+
+        value_type& value() BOOST_NOEXCEPT
+        {
+          return *reinterpret_cast<value_type*>(buf.address());
+        }
+      };
+
+      template <class Node, class VoidPtr> struct bucket
+      {
+        typedef typename boost::pointer_traits<VoidPtr>::template rebind_to<
+          Node>::type node_pointer;
+
+        typedef typename boost::pointer_traits<VoidPtr>::template rebind_to<
+          bucket>::type bucket_pointer;
+
+        node_pointer next;
+
+        bucket() BOOST_NOEXCEPT : next() {}
+      };
+
+      template <class Bucket> struct bucket_group
+      {
+        typedef typename Bucket::bucket_pointer bucket_pointer;
+        typedef
+          typename boost::pointer_traits<bucket_pointer>::template rebind_to<
+            bucket_group>::type bucket_group_pointer;
+
+        BOOST_STATIC_CONSTANT(std::size_t, N = sizeof(std::size_t) * CHAR_BIT);
+
+        bucket_pointer buckets;
+        std::size_t bitmask;
+        bucket_group_pointer next, prev;
+
+        bucket_group() BOOST_NOEXCEPT : buckets(), bitmask(0), next(), prev() {}
+        ~bucket_group() {}
+      };
+
+      inline std::size_t set_bit(std::size_t n) { return std::size_t(1) << n; }
+
+      inline std::size_t reset_bit(std::size_t n)
+      {
+        return ~(std::size_t(1) << n);
+      }
+
+      inline std::size_t reset_first_bits(std::size_t n) // n>0
+      {
+        return ~(~(std::size_t(0)) >> (sizeof(std::size_t) * 8 - n));
+      }
+
+      template <class Bucket> struct grouped_bucket_iterator
+      {
+      public:
+        typedef typename Bucket::bucket_pointer bucket_pointer;
+        typedef
+          typename boost::pointer_traits<bucket_pointer>::template rebind_to<
+            bucket_group<Bucket> >::type bucket_group_pointer;
+
+        typedef Bucket value_type;
+        typedef typename boost::pointer_traits<bucket_pointer>::difference_type
+          difference_type;
+        typedef Bucket& reference;
+        typedef Bucket* pointer;
+        typedef std::forward_iterator_tag iterator_category;
+
+      private:
+        bucket_pointer p;
+        bucket_group_pointer pbg;
+
+      public:
+        grouped_bucket_iterator() : p(), pbg() {}
+
+        reference operator*() const BOOST_NOEXCEPT { return dereference(); }
+        pointer operator->() const BOOST_NOEXCEPT
+        {
+          return boost::to_address(p);
+        }
+
+        grouped_bucket_iterator& operator++() BOOST_NOEXCEPT
+        {
+          increment();
+          return *this;
+        }
+
+        grouped_bucket_iterator operator++(int) BOOST_NOEXCEPT
+        {
+          grouped_bucket_iterator old = *this;
+          increment();
+          return old;
+        }
+
+        bool operator==(
+          grouped_bucket_iterator const& other) const BOOST_NOEXCEPT
+        {
+          return equal(other);
+        }
+
+        bool operator!=(
+          grouped_bucket_iterator const& other) const BOOST_NOEXCEPT
+        {
+          return !equal(other);
+        }
+
+      private:
+        template <typename, typename, typename>
+        friend class grouped_bucket_array;
+
+        BOOST_STATIC_CONSTANT(std::size_t, N = bucket_group<Bucket>::N);
+
+        grouped_bucket_iterator(bucket_pointer p_, bucket_group_pointer pbg_)
+            : p(p_), pbg(pbg_)
+        {
+        }
+
+        Bucket& dereference() const BOOST_NOEXCEPT { return *p; }
+
+        bool equal(const grouped_bucket_iterator& x) const BOOST_NOEXCEPT
+        {
+          return p == x.p;
+        }
+
+        void increment() BOOST_NOEXCEPT
+        {
+          std::size_t const offset = static_cast<std::size_t>(p - pbg->buckets);
+
+          std::size_t n = std::size_t(boost::core::countr_zero(
+            pbg->bitmask & reset_first_bits(offset + 1)));
+
+          if (n < N) {
+            p = pbg->buckets + static_cast<difference_type>(n);
+          } else {
+            pbg = pbg->next;
+
+            std::ptrdiff_t x = boost::core::countr_zero(pbg->bitmask);
+            p = pbg->buckets + x;
+          }
+        }
+      };
+
+      template <class Node> struct const_grouped_local_bucket_iterator;
+
+      template <class Node> struct grouped_local_bucket_iterator
+      {
+        typedef typename Node::node_pointer node_pointer;
+
+      public:
+        typedef typename Node::value_type value_type;
+        typedef value_type element_type;
+        typedef value_type* pointer;
+        typedef value_type& reference;
+        typedef std::ptrdiff_t difference_type;
+        typedef std::forward_iterator_tag iterator_category;
+
+        grouped_local_bucket_iterator() : p() {}
+
+        reference operator*() const BOOST_NOEXCEPT { return dereference(); }
+
+        pointer operator->() const BOOST_NOEXCEPT
+        {
+          return boost::to_address(p);
+        }
+
+        grouped_local_bucket_iterator& operator++() BOOST_NOEXCEPT
+        {
+          increment();
+          return *this;
+        }
+
+        grouped_local_bucket_iterator operator++(int) BOOST_NOEXCEPT
+        {
+          grouped_local_bucket_iterator old = *this;
+          increment();
+          return old;
+        }
+
+        bool operator==(
+          grouped_local_bucket_iterator const& other) const BOOST_NOEXCEPT
+        {
+          return equal(other);
+        }
+
+        bool operator!=(
+          grouped_local_bucket_iterator const& other) const BOOST_NOEXCEPT
+        {
+          return !equal(other);
+        }
+
+      private:
+        template <typename, typename, typename>
+        friend class grouped_bucket_array;
+
+        template <class> friend struct const_grouped_local_bucket_iterator;
+
+        grouped_local_bucket_iterator(node_pointer p_) : p(p_) {}
+
+        value_type& dereference() const BOOST_NOEXCEPT { return p->value(); }
+
+        bool equal(const grouped_local_bucket_iterator& x) const BOOST_NOEXCEPT
+        {
+          return p == x.p;
+        }
+
+        void increment() BOOST_NOEXCEPT { p = p->next; }
+
+        node_pointer p;
+      };
+
+      template <class Node> struct const_grouped_local_bucket_iterator
+      {
+        typedef typename Node::node_pointer node_pointer;
+
+      public:
+        typedef typename Node::value_type const value_type;
+        typedef value_type const element_type;
+        typedef value_type const* pointer;
+        typedef value_type const& reference;
+        typedef std::ptrdiff_t difference_type;
+        typedef std::forward_iterator_tag iterator_category;
+
+        const_grouped_local_bucket_iterator() : p() {}
+        const_grouped_local_bucket_iterator(
+          grouped_local_bucket_iterator<Node> it)
+            : p(it.p)
+        {
+        }
+
+        reference operator*() const BOOST_NOEXCEPT { return dereference(); }
+
+        pointer operator->() const BOOST_NOEXCEPT
+        {
+          return boost::to_address(p);
+        }
+
+        const_grouped_local_bucket_iterator& operator++() BOOST_NOEXCEPT
+        {
+          increment();
+          return *this;
+        }
+
+        const_grouped_local_bucket_iterator operator++(int) BOOST_NOEXCEPT
+        {
+          const_grouped_local_bucket_iterator old = *this;
+          increment();
+          return old;
+        }
+
+        bool operator==(
+          const_grouped_local_bucket_iterator const& other) const BOOST_NOEXCEPT
+        {
+          return equal(other);
+        }
+
+        bool operator!=(
+          const_grouped_local_bucket_iterator const& other) const BOOST_NOEXCEPT
+        {
+          return !equal(other);
+        }
+
+      private:
+        template <typename, typename, typename>
+        friend class grouped_bucket_array;
+
+        const_grouped_local_bucket_iterator(node_pointer p_) : p(p_) {}
+
+        value_type& dereference() const BOOST_NOEXCEPT { return p->value(); }
+
+        bool equal(
+          const const_grouped_local_bucket_iterator& x) const BOOST_NOEXCEPT
+        {
+          return p == x.p;
+        }
+
+        void increment() BOOST_NOEXCEPT { p = p->next; }
+
+        node_pointer p;
+      };
+
+      template <class T> struct span
+      {
+        T* begin() const BOOST_NOEXCEPT { return data; }
+        T* end() const BOOST_NOEXCEPT { return data + size; }
+
+        T* data;
+        std::size_t size;
+
+        span(T* data_, std::size_t size_) : data(data_), size(size_) {}
+      };
+
+      template <class Bucket, class Allocator, class SizePolicy>
+      class grouped_bucket_array
+          : boost::empty_value<typename boost::allocator_rebind<Allocator,
+              node<typename boost::allocator_value_type<Allocator>::type,
+                typename boost::allocator_void_pointer<Allocator>::type> >::
+                type>
+      {
+        BOOST_MOVABLE_BUT_NOT_COPYABLE(grouped_bucket_array)
+
+        typedef typename boost::allocator_value_type<Allocator>::type
+          allocator_value_type;
+        typedef
+          typename boost::allocator_void_pointer<Allocator>::type void_pointer;
+        typedef typename boost::allocator_difference_type<Allocator>::type
+          difference_type;
+
+      public:
+        typedef typename boost::allocator_rebind<Allocator,
+          node<allocator_value_type, void_pointer> >::type node_allocator_type;
+
+        typedef node<allocator_value_type, void_pointer> node_type;
+        typedef typename boost::allocator_pointer<node_allocator_type>::type
+          node_pointer;
+        typedef SizePolicy size_policy;
+
+      private:
+        typedef typename boost::allocator_rebind<Allocator, Bucket>::type
+          bucket_allocator_type;
+        typedef typename boost::allocator_pointer<bucket_allocator_type>::type
+          bucket_pointer;
+        typedef boost::pointer_traits<bucket_pointer> bucket_pointer_traits;
+
+        typedef bucket_group<Bucket> group;
+        typedef typename boost::allocator_rebind<Allocator, group>::type
+          group_allocator_type;
+        typedef typename boost::allocator_pointer<group_allocator_type>::type
+          group_pointer;
+        typedef typename boost::pointer_traits<group_pointer>
+          group_pointer_traits;
+
+      public:
+        typedef Bucket value_type;
+        typedef Bucket bucket_type;
+        typedef std::size_t size_type;
+        typedef Allocator allocator_type;
+        typedef grouped_bucket_iterator<Bucket> iterator;
+        typedef grouped_local_bucket_iterator<node_type> local_iterator;
+        typedef const_grouped_local_bucket_iterator<node_type>
+          const_local_iterator;
+
+      private:
+        std::size_t size_index_, size_;
+        bucket_pointer buckets;
+        group_pointer groups;
+
+      public:
+        static std::size_t bucket_count_for(std::size_t num_buckets)
+        {
+          if (num_buckets == 0) {
+            return 0;
+          }
+          return size_policy::size(size_policy::size_index(num_buckets));
+        }
+
+        grouped_bucket_array()
+            : empty_value<node_allocator_type>(
+                empty_init_t(), node_allocator_type()),
+              size_index_(0), size_(0), buckets(), groups()
+        {
+        }
+
+        grouped_bucket_array(size_type n, const Allocator& al)
+            : empty_value<node_allocator_type>(empty_init_t(), al),
+              size_index_(0),
+              size_(0), buckets(), groups()
+        {
+          if (n == 0) {
+            return;
+          }
+
+          size_index_ = size_policy::size_index(n);
+          size_ = size_policy::size(size_index_);
+
+          bucket_allocator_type bucket_alloc = this->get_bucket_allocator();
+          group_allocator_type group_alloc = this->get_group_allocator();
+
+          size_type const num_buckets = buckets_len();
+          size_type const num_groups = groups_len();
+
+          buckets = boost::allocator_allocate(bucket_alloc, num_buckets);
+          BOOST_TRY
+          {
+            groups = boost::allocator_allocate(group_alloc, num_groups);
+
+            bucket_type* pb = boost::to_address(buckets);
+            for (size_type i = 0; i < num_buckets; ++i) {
+              new (pb + i) bucket_type();
+            }
+
+            group* pg = boost::to_address(groups);
+            for (size_type i = 0; i < num_groups; ++i) {
+              new (pg + i) group();
+            }
+          }
+          BOOST_CATCH(...)
+          {
+            boost::allocator_deallocate(bucket_alloc, buckets, num_buckets);
+            BOOST_RETHROW
+          }
+          BOOST_CATCH_END
+
+          size_type const N = group::N;
+          group_pointer pbg =
+            groups + static_cast<difference_type>(num_groups - 1);
+
+          pbg->buckets =
+            buckets + static_cast<difference_type>(N * (size_ / N));
+          pbg->bitmask = set_bit(size_ % N);
+          pbg->next = pbg->prev = pbg;
+        }
+
+        ~grouped_bucket_array() { this->deallocate(); }
+
+        grouped_bucket_array(
+          BOOST_RV_REF(grouped_bucket_array) other) BOOST_NOEXCEPT
+            : empty_value<node_allocator_type>(
+                empty_init_t(), other.get_node_allocator()),
+              size_index_(other.size_index_),
+              size_(other.size_),
+              buckets(other.buckets),
+              groups(other.groups)
+        {
+          other.size_ = 0;
+          other.size_index_ = 0;
+          other.buckets = bucket_pointer();
+          other.groups = group_pointer();
+        }
+
+        grouped_bucket_array& operator=(
+          BOOST_RV_REF(grouped_bucket_array) other) BOOST_NOEXCEPT
+        {
+          BOOST_ASSERT(
+            this->get_node_allocator() == other.get_node_allocator());
+
+          if (this == boost::addressof(other)) {
+            return *this;
+          }
+
+          this->deallocate();
+          size_index_ = other.size_index_;
+          size_ = other.size_;
+
+          buckets = other.buckets;
+          groups = other.groups;
+
+          other.size_index_ = 0;
+          other.size_ = 0;
+          other.buckets = bucket_pointer();
+          other.groups = group_pointer();
+
+          return *this;
+        }
+
+        void deallocate() BOOST_NOEXCEPT
+        {
+          if (buckets) {
+            bucket_allocator_type bucket_alloc = this->get_bucket_allocator();
+            boost::allocator_deallocate(
+              bucket_alloc, buckets, this->buckets_len());
+
+            buckets = bucket_pointer();
+          }
+
+          if (groups) {
+            group_allocator_type group_alloc = this->get_group_allocator();
+            boost::allocator_deallocate(
+              group_alloc, groups, this->groups_len());
+
+            groups = group_pointer();
+          }
+        }
+
+        void swap(grouped_bucket_array& other)
+        {
+          std::swap(size_index_, other.size_index_);
+          std::swap(size_, other.size_);
+          std::swap(buckets, other.buckets);
+          std::swap(groups, other.groups);
+
+          bool b = boost::allocator_propagate_on_container_swap<
+            allocator_type>::type::value;
+          if (b) {
+            boost::swap(get_node_allocator(), other.get_node_allocator());
+          }
+        }
+
+        node_allocator_type const& get_node_allocator() const
+        {
+          return empty_value<node_allocator_type>::get();
+        }
+
+        node_allocator_type& get_node_allocator()
+        {
+          return empty_value<node_allocator_type>::get();
+        }
+
+        bucket_allocator_type get_bucket_allocator() const
+        {
+          return this->get_node_allocator();
+        }
+
+        group_allocator_type get_group_allocator() const
+        {
+          return this->get_node_allocator();
+        }
+
+        size_type buckets_len() const BOOST_NOEXCEPT { return size_ + 1; }
+
+        size_type groups_len() const BOOST_NOEXCEPT
+        {
+          return size_ / group::N + 1;
+        }
+
+        void reset_allocator(Allocator const& allocator_)
+        {
+          this->get_node_allocator() = node_allocator_type(allocator_);
+        }
+
+        size_type bucket_count() const { return size_; }
+
+        iterator begin() const { return size_ == 0 ? end() : ++at(size_); }
+
+        iterator end() const
+        {
+          // micro optimization: no need to return the bucket group
+          // as end() is not incrementable
+          iterator pbg;
+          pbg.p =
+            buckets + static_cast<difference_type>(this->buckets_len() - 1);
+          return pbg;
+        }
+
+        local_iterator begin(size_type n) const
+        {
+          if (size_ == 0) {
+            return this->end(n);
+          }
+
+          return local_iterator(
+            (buckets + static_cast<difference_type>(n))->next);
+        }
+
+        local_iterator end(size_type) const { return local_iterator(); }
+
+        size_type capacity() const BOOST_NOEXCEPT { return size_; }
+
+        iterator at(size_type n) const
+        {
+          if (size_ > 0) {
+            std::size_t const N = group::N;
+
+            iterator pbg(buckets + static_cast<difference_type>(n),
+              groups + static_cast<difference_type>(n / N));
+
+            return pbg;
+          } else {
+            return this->end();
+          }
+        }
+
+        span<Bucket> raw()
+        {
+          BOOST_ASSERT(size_ == 0 || size_ < this->buckets_len());
+          return span<Bucket>(boost::to_address(buckets), size_);
+        }
+
+        size_type position(std::size_t hash) const
+        {
+          return size_policy::position(hash, size_index_);
+        }
+
+        void clear()
+        {
+          this->deallocate();
+          size_index_ = 0;
+          size_ = 0;
+        }
+
+        void append_bucket_group(iterator itb) BOOST_NOEXCEPT
+        {
+          std::size_t const N = group::N;
+
+          bool const is_empty_bucket = (!itb->next);
+          if (is_empty_bucket) {
+            bucket_pointer pb = itb.p;
+            group_pointer pbg = itb.pbg;
+
+            std::size_t n =
+              static_cast<std::size_t>(boost::to_address(pb) - &buckets[0]);
+
+            bool const is_empty_group = (!pbg->bitmask);
+            if (is_empty_group) {
+              size_type const num_groups = this->groups_len();
+              group_pointer last_group =
+                groups + static_cast<difference_type>(num_groups - 1);
+
+              pbg->buckets =
+                buckets + static_cast<difference_type>(N * (n / N));
+              pbg->next = last_group->next;
+              pbg->next->prev = pbg;
+              pbg->prev = last_group;
+              pbg->prev->next = pbg;
+            }
+
+            pbg->bitmask |= set_bit(n % N);
+          }
+        }
+
+        void insert_node(iterator itb, node_pointer p) BOOST_NOEXCEPT
+        {
+          this->append_bucket_group(itb);
+
+          p->next = itb->next;
+          itb->next = p;
+        }
+
+        void insert_node_hint(
+          iterator itb, node_pointer p, node_pointer hint) BOOST_NOEXCEPT
+        {
+          this->append_bucket_group(itb);
+
+          if (hint) {
+            p->next = hint->next;
+            hint->next = p;
+          } else {
+            p->next = itb->next;
+            itb->next = p;
+          }
+        }
+
+        void extract_node(iterator itb, node_pointer p) BOOST_NOEXCEPT
+        {
+          node_pointer* pp = boost::addressof(itb->next);
+          while ((*pp) != p)
+            pp = boost::addressof((*pp)->next);
+          *pp = p->next;
+          if (!itb->next)
+            unlink_bucket(itb);
+        }
+
+        void extract_node_after(iterator itb, node_pointer* pp) BOOST_NOEXCEPT
+        {
+          *pp = (*pp)->next;
+          if (!itb->next)
+            unlink_bucket(itb);
+        }
+
+        void unlink_empty_buckets() BOOST_NOEXCEPT
+        {
+          std::size_t const N = group::N;
+
+          group_pointer pbg = groups,
+                        last = groups + static_cast<difference_type>(
+                                          this->groups_len() - 1);
+
+          for (; pbg != last; ++pbg) {
+            if (!pbg->buckets) {
+              continue;
+            }
+
+            for (std::size_t n = 0; n < N; ++n) {
+              bucket_pointer bs = pbg->buckets;
+              bucket_type& b = bs[static_cast<std::ptrdiff_t>(n)];
+              if (!b.next)
+                pbg->bitmask &= reset_bit(n);
+            }
+            if (!pbg->bitmask && pbg->next)
+              unlink_group(pbg);
+          }
+
+          // do not check end bucket
+          for (std::size_t n = 0; n < size_ % N; ++n) {
+            if (!pbg->buckets[static_cast<std::ptrdiff_t>(n)].next)
+              pbg->bitmask &= reset_bit(n);
+          }
+        }
+
+        void unlink_bucket(iterator itb)
+        {
+          typename iterator::bucket_pointer p = itb.p;
+          typename iterator::bucket_group_pointer pbg = itb.pbg;
+          if (!(pbg->bitmask &=
+                reset_bit(static_cast<std::size_t>(p - pbg->buckets))))
+            unlink_group(pbg);
+        }
+
+      private:
+        void unlink_group(group_pointer pbg)
+        {
+          pbg->next->prev = pbg->prev;
+          pbg->prev->next = pbg->next;
+          pbg->prev = pbg->next = group_pointer();
+        }
+      };
+    } // namespace detail
+  }   // namespace unordered
+} // namespace boost
+
+#endif // BOOST_UNORDERED_DETAIL_FCA_HPP

include/boost/unordered/detail/fwd.hpp

@@ -1,5 +1,6 @@
 
 // Copyright (C) 2008-2016 Daniel James.
+// Copyright (C) 2022 Christian Mazakas
 // Distributed under the Boost Software License, Version 1.0. (See accompanying
 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
 
@@ -31,7 +32,7 @@
 // 2012 = VC+11 = BOOST_MSVC 1700 Hopefully!
 // I have no idea when Dinkumware added it, probably a lot
 // earlier than this check.
-#if BOOST_LIB_STD_DINKUMWARE >= BOOST_VERSION_NUMBER(6, 50, 0) ||              \
+#if BOOST_LIB_STD_DINKUMWARE >= BOOST_VERSION_NUMBER(6, 10, 0) ||              \
   BOOST_COMP_MSVC >= BOOST_VERSION_NUMBER(17, 0, 0)
 #define BOOST_UNORDERED_HAVE_PIECEWISE_CONSTRUCT 1
 #endif

include/boost/unordered/detail/map.hpp

@@ -1,5 +1,6 @@
 
 // Copyright (C) 2005-2016 Daniel James
+// Copyright (C) 2022 Christian Mazakas
 // Distributed under the Boost Software License, Version 1.0. (See accompanying
 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
 
@@ -25,25 +26,18 @@ namespace boost {
         typedef boost::unordered::detail::allocator_traits<value_allocator>
           value_allocator_traits;
 
-        typedef boost::unordered::detail::pick_node<A, value_type> pick;
-        typedef typename pick::node node;
-        typedef typename pick::bucket bucket;
-        typedef typename pick::link_pointer link_pointer;
-
         typedef boost::unordered::detail::table<types> table;
         typedef boost::unordered::detail::map_extractor<value_type> extractor;
 
-        typedef typename boost::unordered::detail::pick_policy<K>::type policy;
+        typedef typename boost::allocator_void_pointer<value_allocator>::type
+          void_pointer;
 
-        typedef boost::unordered::iterator_detail::iterator<node> iterator;
-        typedef boost::unordered::iterator_detail::c_iterator<node> c_iterator;
-        typedef boost::unordered::iterator_detail::l_iterator<node> l_iterator;
-        typedef boost::unordered::iterator_detail::cl_iterator<node>
-          cl_iterator;
+        typedef boost::unordered::node_handle_map<
+          node<value_type, void_pointer>, K, M, A>
+          node_type;
 
-        typedef boost::unordered::node_handle_map<node, K, M, A> node_type;
-        typedef boost::unordered::insert_return_type_map<node, K, M, A>
-          insert_return_type;
+        typedef typename table::iterator iterator;
+        typedef boost::unordered::insert_return_type_map<iterator, node_type> insert_return_type;
       };
 
       template <typename K, typename M, typename H, typename P, typename A>

include/boost/unordered/detail/prime_fmod.hpp

@@ -0,0 +1,262 @@
+// Copyright (C) 2022 Joaquin M Lopez Munoz.
+// Copyright (C) 2022 Christian Mazakas
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+
+#ifndef BOOST_UNORDERED_DETAIL_PRIME_FMOD_HPP
+#define BOOST_UNORDERED_DETAIL_PRIME_FMOD_HPP
+
+#include <boost/cstdint.hpp>
+#include <boost/preprocessor/seq/enum.hpp>
+#include <boost/preprocessor/seq/for_each.hpp>
+#include <boost/preprocessor/seq/size.hpp>
+
+#include <boost/config.hpp>
+
+#include <climits>
+#include <cstddef>
+
+#if defined(SIZE_MAX)
+#if ((((SIZE_MAX >> 16) >> 16) >> 16) >> 15) != 0
+#define BOOST_UNORDERED_FCA_HAS_64B_SIZE_T
+#endif
+#elif defined(UINTPTR_MAX) /* used as proxy for std::size_t */
+#if ((((UINTPTR_MAX >> 16) >> 16) >> 16) >> 15) != 0
+#define BOOST_UNORDERED_FCA_HAS_64B_SIZE_T
+#endif
+#endif
+
+#if defined(BOOST_UNORDERED_FCA_HAS_64B_SIZE_T) && defined(_MSC_VER)
+#include <intrin.h>
+#endif
+
+namespace boost {
+  namespace unordered {
+    namespace detail {
+      template <class = void> struct prime_fmod_size
+      {
+        // Because we compile for C++03, we don't have access to any inline
+        // initialization for array data members so the definitions must exist
+        // out-of-line. To keep the library header-only, we introduce a dummy
+        // template parameter which permits the definition to be included in
+        // multiple TUs without conflict.
+        //
+        static std::size_t sizes[];
+        static std::size_t const sizes_len;
+        static std::size_t (*positions[])(std::size_t);
+
+#if defined(BOOST_UNORDERED_FCA_HAS_64B_SIZE_T)
+        static boost::uint64_t inv_sizes32[];
+        static std::size_t const inv_sizes32_len;
+#endif /* defined(BOOST_UNORDERED_FCA_HAS_64B_SIZE_T) */
+
+        static inline std::size_t size_index(std::size_t n)
+        {
+          std::size_t i = 0;
+          for (; i < (sizes_len - 1); ++i) {
+            if (sizes[i] >= n) {
+              break;
+            }
+          }
+          return i;
+        }
+
+        static inline std::size_t size(std::size_t size_index)
+        {
+          return sizes[size_index];
+        }
+
+        template <std::size_t Size> static std::size_t modulo(std::size_t hash)
+        {
+          return hash % Size;
+        }
+
+#if defined(BOOST_UNORDERED_FCA_HAS_64B_SIZE_T)
+        // We emulate the techniques taken from:
+        // Faster Remainder by Direct Computation: Applications to Compilers and
+        // Software Libraries
+        // https://arxiv.org/abs/1902.01961
+        //
+        // In essence, use fancy math to directly calculate the remainder (aka
+        // modulo) exploiting how compilers transform division
+        //
+
+        static inline boost::uint64_t get_remainder(
+          boost::uint64_t fractional, boost::uint32_t d)
+        {
+#if defined(_MSC_VER)
+          // use MSVC intrinsics when available to avoid promotion to 128 bits
+
+          return __umulh(fractional, d);
+#elif defined(BOOST_HAS_INT128)
+          return static_cast<boost::uint64_t>(
+            ((boost::uint128_type)fractional * d) >> 64);
+#else
+          // portable implementation in the absence of boost::uint128_type on 64
+          // bits, which happens at least in GCC 4.5 and prior
+
+          boost::uint64_t r1 = (fractional & UINT32_MAX) * d;
+          boost::uint64_t r2 = (fractional >> 32) * d;
+          r2 += r1 >> 32;
+          return r2 >> 32;
+#endif /* defined(_MSC_VER) */
+        }
+
+        static inline boost::uint32_t fast_modulo(
+          boost::uint32_t a, boost::uint64_t M, boost::uint32_t d)
+        {
+          boost::uint64_t fractional = M * a;
+          return (boost::uint32_t)(get_remainder(fractional, d));
+        }
+#endif /* defined(BOOST_UNORDERED_FCA_HAS_64B_SIZE_T) */
+
+        static inline std::size_t position(
+          std::size_t hash, std::size_t size_index)
+        {
+#if defined(BOOST_UNORDERED_FCA_HAS_64B_SIZE_T)
+          std::size_t sizes_under_32bit = inv_sizes32_len;
+          if (BOOST_LIKELY(size_index < sizes_under_32bit)) {
+            return fast_modulo(
+              boost::uint32_t(hash) + boost::uint32_t(hash >> 32),
+              inv_sizes32[size_index], boost::uint32_t(sizes[size_index]));
+          } else {
+            return positions[size_index - sizes_under_32bit](hash);
+          }
+#else
+          return positions[size_index](hash);
+#endif /* defined(BOOST_UNORDERED_FCA_HAS_64B_SIZE_T) */
+        }
+      }; // prime_fmod_size
+
+#define BOOST_UNORDERED_PRIME_FMOD_SIZES_32BIT_INCOMPLETE                      \
+  (13ul)(29ul)(53ul)(97ul)(193ul)(389ul)(769ul)(1543ul)(3079ul)(6151ul)(       \
+    12289ul)(24593ul)(49157ul)(98317ul)(196613ul)(393241ul)(786433ul)(         \
+    1572869ul)(3145739ul)(6291469ul)(12582917ul)(25165843ul)(50331653ul)(      \
+    100663319ul)(201326611ul)(402653189ul)(805306457ul)(1610612741ul)(         \
+    3221225473ul)
+
+#if !defined(BOOST_UNORDERED_FCA_HAS_64B_SIZE_T)
+
+#define BOOST_UNORDERED_PRIME_FMOD_SIZES_32BIT                                 \
+  BOOST_UNORDERED_PRIME_FMOD_SIZES_32BIT_INCOMPLETE(4294967291ul)
+
+#define BOOST_UNORDERED_PRIME_FMOD_SIZES_64BIT
+
+#else
+
+#define BOOST_UNORDERED_PRIME_FMOD_SIZES_32BIT                                 \
+  BOOST_UNORDERED_PRIME_FMOD_SIZES_32BIT_INCOMPLETE
+
+// The original sequence here is this:
+// (6442450939ul)
+// (12884901893ul)
+// (25769803751ul)
+// (51539607551ul)
+// (103079215111ul)
+// (206158430209ul)
+// (412316860441ul)
+// (824633720831ul)
+// (1649267441651ul)
+//
+// but this causes problems on versions of mingw where the `long` type is 32
+// bits, even for 64-bit targets. We work around this by replacing the literals
+// with compile-time arithmetic, using bitshifts to reconstruct the number.
+//
+
+// clang-format off
+#define BOOST_UNORDERED_PRIME_FMOD_SIZES_64BIT                                   \
+  ((boost::ulong_long_type(1ul) << 32)   + boost::ulong_long_type(2147483643ul)) \
+  ((boost::ulong_long_type(3ul) << 32)   + boost::ulong_long_type(5ul))          \
+  ((boost::ulong_long_type(5ul) << 32)   + boost::ulong_long_type(4294967271ul)) \
+  ((boost::ulong_long_type(11ul) << 32)  + boost::ulong_long_type(4294967295ul)) \
+  ((boost::ulong_long_type(24ul) << 32)  + boost::ulong_long_type(7ul))          \
+  ((boost::ulong_long_type(48ul) << 32)  + boost::ulong_long_type(1ul))          \
+  ((boost::ulong_long_type(96ul) << 32)  + boost::ulong_long_type(25ul))         \
+  ((boost::ulong_long_type(191ul) << 32) + boost::ulong_long_type(4294967295ul)) \
+  ((boost::ulong_long_type(383ul) << 32) + boost::ulong_long_type(4294967283ul))
+      // clang-format on
+
+#endif /* BOOST_UNORDERED_FCA_HAS_64B_SIZE_T */
+
+#define BOOST_UNORDERED_PRIME_FMOD_SIZES                                       \
+  BOOST_UNORDERED_PRIME_FMOD_SIZES_32BIT BOOST_UNORDERED_PRIME_FMOD_SIZES_64BIT
+
+      template <class T>
+      std::size_t prime_fmod_size<T>::sizes[] = {
+        BOOST_PP_SEQ_ENUM(BOOST_UNORDERED_PRIME_FMOD_SIZES)};
+
+      template <class T>
+      std::size_t const prime_fmod_size<T>::sizes_len = BOOST_PP_SEQ_SIZE(
+        BOOST_UNORDERED_PRIME_FMOD_SIZES);
+
+// Similarly here, we have to re-express the integer initialization using
+// arithmetic such that each literal can fit in a 32-bit value.
+//
+#if defined(BOOST_UNORDERED_FCA_HAS_64B_SIZE_T)
+      // clang-format off
+        template <class T>
+        boost::uint64_t prime_fmod_size<T>::inv_sizes32[] = {
+          (boost::ulong_long_type(330382099ul) << 32) + boost::ulong_long_type(2973438898ul) /* = 1418980313362273202 */,
+          (boost::ulong_long_type(148102320ul) << 32) + boost::ulong_long_type(2369637129ul) /* = 636094623231363849 */,
+          (boost::ulong_long_type(81037118ul) << 32)  + boost::ulong_long_type(3403558990ul) /* = 348051774975651918 */,
+          (boost::ulong_long_type(44278013ul) << 32)  + boost::ulong_long_type(1549730468ul) /* = 190172619316593316 */,
+          (boost::ulong_long_type(22253716ul) << 32)  + boost::ulong_long_type(2403401389ul) /* = 95578984837873325 */,
+          (boost::ulong_long_type(11041047ul) << 32)  + boost::ulong_long_type(143533612ul)  /* = 47420935922132524 */,
+          (boost::ulong_long_type(5585133ul) << 32)   + boost::ulong_long_type(106117528ul)  /* = 23987963684927896 */,
+          (boost::ulong_long_type(2783517ul) << 32)   + boost::ulong_long_type(1572687312ul) /* = 11955116055547344 */,
+          (boost::ulong_long_type(1394922ul) << 32)   + boost::ulong_long_type(3428720239ul) /* = 5991147799191151 */,
+          (boost::ulong_long_type(698255ul) << 32)    + boost::ulong_long_type(552319807ul)  /* = 2998982941588287 */,
+          (boost::ulong_long_type(349496ul) << 32)    + boost::ulong_long_type(3827689953ul) /* = 1501077717772769 */,
+          (boost::ulong_long_type(174641ul) << 32)    + boost::ulong_long_type(3699438549ul) /* = 750081082979285 */,
+          (boost::ulong_long_type(87372ul) << 32)     + boost::ulong_long_type(1912757574ul) /* = 375261795343686 */,
+          (boost::ulong_long_type(43684ul) << 32)     + boost::ulong_long_type(3821029929ul) /* = 187625172388393 */,
+          (boost::ulong_long_type(21844ul) << 32)     + boost::ulong_long_type(3340590800ul) /* = 93822606204624 */,
+          (boost::ulong_long_type(10921ul) << 32)     + boost::ulong_long_type(4175852267ul) /* = 46909513691883 */,
+          (boost::ulong_long_type(5461ul) << 32)      + boost::ulong_long_type(1401829642ul) /* = 23456218233098 */,
+          (boost::ulong_long_type(2730ul) << 32)      + boost::ulong_long_type(2826028947ul) /* = 11728086747027 */,
+          (boost::ulong_long_type(1365ul) << 32)      + boost::ulong_long_type(1411150351ul) /* = 5864041509391 */,
+          (boost::ulong_long_type(682ul) << 32)       + boost::ulong_long_type(2857253105ul) /* = 2932024948977 */,
+          (boost::ulong_long_type(341ul) << 32)       + boost::ulong_long_type(1431073224ul) /* = 1466014921160 */,
+          (boost::ulong_long_type(170ul) << 32)       + boost::ulong_long_type(2862758116ul) /* = 733007198436 */,
+          (boost::ulong_long_type(85ul) << 32)        + boost::ulong_long_type(1431619357ul) /* = 366503839517 */,
+          (boost::ulong_long_type(42ul) << 32)        + boost::ulong_long_type(2863269661ul) /* = 183251896093 */,
+          (boost::ulong_long_type(21ul) << 32)        + boost::ulong_long_type(1431647119ul) /* = 91625960335 */,
+          (boost::ulong_long_type(10ul) << 32)        + boost::ulong_long_type(2863310962ul) /* = 45812983922 */,
+          (boost::ulong_long_type(5ul) << 32)         + boost::ulong_long_type(1431653234ul) /* = 22906489714 */,
+          (boost::ulong_long_type(2ul) << 32)         + boost::ulong_long_type(2863311496ul) /* = 11453246088 */,
+          (boost::ulong_long_type(1ul) << 32)         + boost::ulong_long_type(1431655764ul) /* = 5726623060 */,
+        };
+      // clang-format on
+
+      template <class T>
+      std::size_t const
+        prime_fmod_size<T>::inv_sizes32_len = sizeof(inv_sizes32) /
+                                              sizeof(inv_sizes32[0]);
+
+#endif /* defined(BOOST_UNORDERED_FCA_HAS_64B_SIZE_T) */
+
+#define BOOST_UNORDERED_PRIME_FMOD_POSITIONS_ELEMENT(z, _, n)                  \
+  prime_fmod_size<T>::template modulo<n>,
+
+      template <class T>
+      std::size_t (*prime_fmod_size<T>::positions[])(std::size_t) = {
+#if !defined(BOOST_UNORDERED_FCA_HAS_64B_SIZE_T)
+        BOOST_PP_SEQ_FOR_EACH(BOOST_UNORDERED_PRIME_FMOD_POSITIONS_ELEMENT, ~,
+          BOOST_UNORDERED_PRIME_FMOD_SIZES_32BIT)
+#else
+        BOOST_PP_SEQ_FOR_EACH(BOOST_UNORDERED_PRIME_FMOD_POSITIONS_ELEMENT, ~,
+          BOOST_UNORDERED_PRIME_FMOD_SIZES_64BIT)
+#endif
+      };
+
+#undef BOOST_UNORDERED_PRIME_FMOD_POSITIONS_ELEMENT
+#undef BOOST_UNORDERED_PRIME_FMOD_SIZES
+#undef BOOST_UNORDERED_PRIME_FMOD_SIZES_64BIT
+#undef BOOST_UNORDERED_PRIME_FMOD_SIZES_32BIT
+#undef BOOST_UNORDERED_PRIME_FMOD_SIZES_32BIT_INCOMPLETE
+    } // namespace detail
+  }   // namespace unordered
+} // namespace boost
+
+#endif // BOOST_UNORDERED_DETAIL_PRIME_FMOD_HPP

include/boost/unordered/detail/set.hpp

@@ -1,5 +1,6 @@
 
 // Copyright (C) 2005-2016 Daniel James
+// Copyright (C) 2022 Christian Mazakas
 // Distributed under the Boost Software License, Version 1.0. (See accompanying
 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
 
@@ -24,24 +25,18 @@ namespace boost {
         typedef boost::unordered::detail::allocator_traits<value_allocator>
           value_allocator_traits;
 
-        typedef boost::unordered::detail::pick_node<A, value_type> pick;
-        typedef typename pick::node node;
-        typedef typename pick::bucket bucket;
-        typedef typename pick::link_pointer link_pointer;
-
         typedef boost::unordered::detail::table<types> table;
         typedef boost::unordered::detail::set_extractor<value_type> extractor;
 
-        typedef typename boost::unordered::detail::pick_policy<T>::type policy;
+        typedef typename boost::allocator_void_pointer<value_allocator>::type
+          void_pointer;
 
-        typedef boost::unordered::iterator_detail::c_iterator<node> iterator;
-        typedef boost::unordered::iterator_detail::c_iterator<node> c_iterator;
-        typedef boost::unordered::iterator_detail::cl_iterator<node> l_iterator;
-        typedef boost::unordered::iterator_detail::cl_iterator<node>
-          cl_iterator;
+        typedef boost::unordered::node_handle_set<
+          node<value_type, void_pointer>, T, A>
+          node_type;
 
-        typedef boost::unordered::node_handle_set<node, T, A> node_type;
-        typedef boost::unordered::insert_return_type_set<node, T, A>
+        typedef typename table::c_iterator iterator;
+        typedef boost::unordered::insert_return_type_set<iterator, node_type>
           insert_return_type;
       };
 

include/boost/unordered/detail/type_traits.hpp

@@ -0,0 +1,59 @@
+// Copyright (C) 2022 Christian Mazakas
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+
+#ifndef BOOST_UNORDERED_DETAIL_TYPE_TRAITS_HPP
+#define BOOST_UNORDERED_DETAIL_TYPE_TRAITS_HPP
+
+#include <boost/config.hpp>
+#if defined(BOOST_HAS_PRAGMA_ONCE)
+#pragma once
+#endif
+
+#include <boost/type_traits/integral_constant.hpp>
+#include <boost/type_traits/is_convertible.hpp>
+#include <boost/type_traits/make_void.hpp>
+
+namespace boost {
+  namespace unordered {
+    namespace detail {
+      ////////////////////////////////////////////////////////////////////////////
+      // Type checkers used for the transparent member functions added by C++20
+      // and up
+
+      template <class, class = void>
+      struct is_transparent : public boost::false_type
+      {
+      };
+
+      template <class T>
+      struct is_transparent<T,
+        typename boost::make_void<typename T::is_transparent>::type>
+          : public boost::true_type
+      {
+      };
+
+      template <class, class A, class B> struct are_transparent
+      {
+        static bool const value =
+          is_transparent<A>::value && is_transparent<B>::value;
+      };
+
+      template <class Key, class UnorderedMap> struct transparent_non_iterable
+      {
+        typedef typename UnorderedMap::hasher hash;
+        typedef typename UnorderedMap::key_equal key_equal;
+        typedef typename UnorderedMap::iterator iterator;
+        typedef typename UnorderedMap::const_iterator const_iterator;
+
+        static bool const value =
+          are_transparent<Key, hash, key_equal>::value &&
+          !boost::is_convertible<Key, iterator>::value &&
+          !boost::is_convertible<Key, const_iterator>::value;
+      };
+    } // namespace detail
+  }   // namespace unordered
+} // namespace boost
+
+#endif // BOOST_UNORDERED_DETAIL_TYPE_TRAITS_HPP

include/boost/unordered/detail/xmx.hpp

@@ -0,0 +1,75 @@
+/* 32b/64b xmx mix function.
+ *
+ * Copyright 2022 Peter Dimov.
+ * Copyright 2022 Joaquin M Lopez Munoz.
+ * Distributed under the Boost Software License, Version 1.0.
+ * (See accompanying file LICENSE_1_0.txt or copy at
+ * http://www.boost.org/LICENSE_1_0.txt)
+ *
+ * See https://www.boost.org/libs/unordered for library home page.
+ */
+
+#ifndef BOOST_UNORDERED_DETAIL_XMX_HPP
+#define BOOST_UNORDERED_DETAIL_XMX_HPP
+
+#include <boost/cstdint.hpp>
+#include <climits>
+#include <cstddef>
+
+namespace boost{
+namespace unordered{
+namespace detail{
+
+/* Bit mixer for improvement of statistical properties of hash functions.
+ * The implementation is different on 64bit and 32bit architectures:
+ * 
+ *   - 64bit: same as xmx function in
+ *     http://jonkagstrom.com/bit-mixer-construction/index.html
+ *   - 32bit: generated by Hash Function Prospector
+ *     (https://github.com/skeeto/hash-prospector) and selected as the
+ *     best overall performer in benchmarks of Boost.Unordered flat containers.
+ *     Score assigned by Hash Prospector: 333.7934929677524
+ */
+
+#if defined(SIZE_MAX)
+#if ((((SIZE_MAX >> 16) >> 16) >> 16) >> 15) != 0
+#define BOOST_UNORDERED_64B_ARCHITECTURE /* >64 bits assumed as 64 bits */
+#endif
+#elif defined(UINTPTR_MAX) /* used as proxy for std::size_t */
+#if ((((UINTPTR_MAX >> 16) >> 16) >> 16) >> 15) != 0
+#define BOOST_UNORDERED_64B_ARCHITECTURE
+#endif
+#endif
+
+static inline std::size_t xmx(std::size_t x)noexcept
+{
+#if defined(BOOST_UNORDERED_64B_ARCHITECTURE)
+
+  boost::uint64_t z=(boost::uint64_t)x;
+
+  z^=z>>23;
+  z*=0xff51afd7ed558ccdull;
+  z^=z>>23;
+
+  return (std::size_t)z;
+
+#else /* 32 bits assumed */
+
+  x^=x>>18;
+  x*=0x56b5aaadu;
+  x^=x>>16;
+
+  return x;
+
+#endif
+}
+
+#ifdef BOOST_UNORDERED_64B_ARCHITECTURE
+#undef BOOST_UNORDERED_64B_ARCHITECTURE
+#endif
+
+} /* namespace detail */
+} /* namespace unordered */
+} /* namespace boost */
+
+#endif

include/boost/unordered/hash_traits.hpp

@@ -0,0 +1,44 @@
+/* Hash function characterization.
+ *
+ * Copyright 2022 Joaquin M Lopez Munoz.
+ * Distributed under the Boost Software License, Version 1.0.
+ * (See accompanying file LICENSE_1_0.txt or copy at
+ * http://www.boost.org/LICENSE_1_0.txt)
+ *
+ * See https://www.boost.org/libs/unordered for library home page.
+ */
+
+#ifndef BOOST_UNORDERED_HASH_TRAITS_HPP
+#define BOOST_UNORDERED_HASH_TRAITS_HPP
+
+#include <boost/type_traits/make_void.hpp>
+#include <type_traits>
+
+namespace boost{
+namespace unordered{
+
+namespace detail{
+
+template<typename Hash,typename=void>
+struct hash_is_avalanching_impl:std::false_type{};
+
+template<typename Hash>
+struct hash_is_avalanching_impl<Hash,void_t<typename Hash::is_avalanching>>:
+  std::true_type{};
+
+} /* namespace detail */
+
+/* Each trait can be partially specialized by users for concrete hash functions
+ * when actual characterization differs from default.
+ */
+
+/* Derived from std::true_type if the type Hash::is_avalanching is present,
+ * derived from std::false_type otherwise.
+ */
+template<typename Hash>
+struct hash_is_avalanching:detail::hash_is_avalanching_impl<Hash>::type{};
+
+} /* namespace unordered */
+} /* namespace boost */
+
+#endif

include/boost/unordered/unordered_flat_map.hpp

@@ -0,0 +1,619 @@
+// Copyright (C) 2022 Christian Mazakas
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+
+#ifndef BOOST_UNORDERED_UNORDERED_FLAT_MAP_HPP_INCLUDED
+#define BOOST_UNORDERED_UNORDERED_FLAT_MAP_HPP_INCLUDED
+
+#include <boost/config.hpp>
+#if defined(BOOST_HAS_PRAGMA_ONCE)
+#pragma once
+#endif
+
+#include <boost/unordered/detail/foa.hpp>
+#include <boost/unordered/detail/type_traits.hpp>
+#include <boost/unordered/unordered_flat_map_fwd.hpp>
+
+#include <boost/core/allocator_access.hpp>
+#include <boost/functional/hash.hpp>
+#include <boost/throw_exception.hpp>
+
+#include <initializer_list>
+#include <iterator>
+#include <stdexcept>
+#include <type_traits>
+#include <utility>
+
+namespace boost {
+  namespace unordered {
+
+#if defined(BOOST_MSVC)
+#pragma warning(push)
+#pragma warning(disable : 4714) /* marked as __forceinline not inlined */
+#endif
+
+    template <class Key, class T, class Hash, class KeyEqual, class Allocator>
+    class unordered_flat_map
+    {
+      struct map_types
+      {
+        using key_type = Key;
+        using raw_key_type = typename std::remove_const<Key>::type;
+        using raw_mapped_type = typename std::remove_const<T>::type;
+
+        using init_type = std::pair<raw_key_type, raw_mapped_type>;
+        using moved_type = std::pair<raw_key_type&&, raw_mapped_type&&>;
+        using value_type = std::pair<Key const, T>;
+
+        template <class K, class V>
+        static raw_key_type const& extract(std::pair<K, V> const& kv)
+        {
+          return kv.first;
+        }
+
+        static moved_type move(value_type& x)
+        {
+          // TODO: we probably need to launder here
+          return {std::move(const_cast<raw_key_type&>(x.first)),
+            std::move(const_cast<raw_mapped_type&>(x.second))};
+        }
+      };
+
+      using table_type = detail::foa::table<map_types, Hash, KeyEqual,
+        typename boost::allocator_rebind<Allocator,
+          typename map_types::value_type>::type>;
+
+      table_type table_;
+
+      template <class K, class V, class H, class KE, class A, class Pred>
+      typename unordered_flat_map<K, V, H, KE, A>::size_type friend erase_if(
+        unordered_flat_map<K, V, H, KE, A>& set, Pred pred);
+
+    public:
+      using key_type = Key;
+      using mapped_type = T;
+      using value_type = typename map_types::value_type;
+      using init_type = typename map_types::init_type;
+      using size_type = std::size_t;
+      using difference_type = std::ptrdiff_t;
+      using hasher = Hash;
+      using key_equal = KeyEqual;
+      using allocator_type = Allocator;
+      using reference = value_type&;
+      using const_reference = value_type const&;
+      using pointer = typename boost::allocator_pointer<allocator_type>::type;
+      using const_pointer =
+        typename boost::allocator_const_pointer<allocator_type>::type;
+      using iterator = typename table_type::iterator;
+      using const_iterator = typename table_type::const_iterator;
+
+      unordered_flat_map() : unordered_flat_map(0) {}
+
+      explicit unordered_flat_map(size_type n, hasher const& h = hasher(),
+        key_equal const& pred = key_equal(),
+        allocator_type const& a = allocator_type())
+          : table_(n, h, pred, a)
+      {
+      }
+
+      unordered_flat_map(size_type n, allocator_type const& a)
+          : unordered_flat_map(n, hasher(), key_equal(), a)
+      {
+      }
+
+      unordered_flat_map(size_type n, hasher const& h, allocator_type const& a)
+          : unordered_flat_map(n, h, key_equal(), a)
+      {
+      }
+
+      explicit unordered_flat_map(allocator_type const& a)
+          : unordered_flat_map(0, a)
+      {
+      }
+
+      template <class Iterator>
+      unordered_flat_map(Iterator first, Iterator last, size_type n = 0,
+        hasher const& h = hasher(), key_equal const& pred = key_equal(),
+        allocator_type const& a = allocator_type())
+          : unordered_flat_map(n, h, pred, a)
+      {
+        this->insert(first, last);
+      }
+
+      template <class Iterator>
+      unordered_flat_map(
+        Iterator first, Iterator last, size_type n, allocator_type const& a)
+          : unordered_flat_map(first, last, n, hasher(), key_equal(), a)
+      {
+      }
+
+      template <class Iterator>
+      unordered_flat_map(Iterator first, Iterator last, size_type n,
+        hasher const& h, allocator_type const& a)
+          : unordered_flat_map(first, last, n, h, key_equal(), a)
+      {
+      }
+
+      unordered_flat_map(unordered_flat_map const& other) : table_(other.table_)
+      {
+      }
+
+      unordered_flat_map(
+        unordered_flat_map const& other, allocator_type const& a)
+          : table_(other.table_, a)
+      {
+      }
+
+      unordered_flat_map(unordered_flat_map&& other)
+        noexcept(std::is_nothrow_move_constructible<hasher>::value&&
+            std::is_nothrow_move_constructible<key_equal>::value&&
+              std::is_nothrow_move_constructible<allocator_type>::value)
+          : table_(std::move(other.table_))
+      {
+      }
+
+      unordered_flat_map(unordered_flat_map&& other, allocator_type const& al)
+          : table_(std::move(other.table_), al)
+      {
+      }
+
+      unordered_flat_map(std::initializer_list<value_type> ilist,
+        size_type n = 0, hasher const& h = hasher(),
+        key_equal const& pred = key_equal(),
+        allocator_type const& a = allocator_type())
+          : unordered_flat_map(ilist.begin(), ilist.end(), n, h, pred, a)
+      {
+      }
+
+      unordered_flat_map(std::initializer_list<value_type> init, size_type n,
+        allocator_type const& a)
+          : unordered_flat_map(init, n, hasher(), key_equal(), a)
+      {
+      }
+
+      unordered_flat_map(std::initializer_list<value_type> init, size_type n,
+        hasher const& h, allocator_type const& a)
+          : unordered_flat_map(init, n, h, key_equal(), a)
+      {
+      }
+
+      ~unordered_flat_map() = default;
+
+      unordered_flat_map& operator=(unordered_flat_map const& other)
+      {
+        table_ = other.table_;
+        return *this;
+      }
+
+      unordered_flat_map& operator=(unordered_flat_map&& other) noexcept(
+        noexcept(std::declval<table_type&>() = std::declval<table_type&&>()))
+      {
+        table_ = std::move(other.table_);
+        return *this;
+      }
+
+      allocator_type get_allocator() const noexcept
+      {
+        return table_.get_allocator();
+      }
+
+      /// Iterators
+      ///
+
+      iterator begin() noexcept { return table_.begin(); }
+      const_iterator begin() const noexcept { return table_.begin(); }
+      const_iterator cbegin() const noexcept { return table_.cbegin(); }
+
+      iterator end() noexcept { return table_.end(); }
+      const_iterator end() const noexcept { return table_.end(); }
+      const_iterator cend() const noexcept { return table_.cend(); }
+
+      /// Capacity
+      ///
+
+      BOOST_ATTRIBUTE_NODISCARD bool empty() const noexcept
+      {
+        return table_.empty();
+      }
+
+      size_type size() const noexcept { return table_.size(); }
+
+      size_type max_size() const noexcept { return table_.max_size(); }
+
+      /// Modifiers
+      ///
+
+      void clear() noexcept { table_.clear(); }
+
+      template <class Ty>
+      BOOST_FORCEINLINE auto insert(Ty&& value)
+        -> decltype(table_.insert(std::forward<Ty>(value)))
+      {
+        return table_.insert(std::forward<Ty>(value));
+      }
+
+      BOOST_FORCEINLINE std::pair<iterator, bool> insert(init_type&& value)
+      {
+        return table_.insert(std::move(value));
+      }
+
+      template <class Ty>
+      BOOST_FORCEINLINE auto insert(const_iterator, Ty&& value)
+        -> decltype(table_.insert(std::forward<Ty>(value)).first)
+      {
+        return table_.insert(std::forward<Ty>(value)).first;
+      }
+
+      BOOST_FORCEINLINE iterator insert(const_iterator, init_type&& value)
+      {
+        return table_.insert(std::move(value)).first;
+      }
+
+      template <class InputIterator>
+      BOOST_FORCEINLINE void insert(InputIterator first, InputIterator last)
+      {
+        for (auto pos = first; pos != last; ++pos) {
+          table_.emplace(*pos);
+        }
+      }
+
+      void insert(std::initializer_list<value_type> ilist)
+      {
+        this->insert(ilist.begin(), ilist.end());
+      }
+
+      template <class M>
+      std::pair<iterator, bool> insert_or_assign(key_type const& key, M&& obj)
+      {
+        auto iter_bool_pair = table_.try_emplace(key, std::forward<M>(obj));
+        if (iter_bool_pair.second) {
+          return iter_bool_pair;
+        }
+        iter_bool_pair.first->second = std::forward<M>(obj);
+        return iter_bool_pair;
+      }
+
+      template <class M>
+      std::pair<iterator, bool> insert_or_assign(key_type&& key, M&& obj)
+      {
+        auto iter_bool_pair =
+          table_.try_emplace(std::move(key), std::forward<M>(obj));
+        if (iter_bool_pair.second) {
+          return iter_bool_pair;
+        }
+        iter_bool_pair.first->second = std::forward<M>(obj);
+        return iter_bool_pair;
+      }
+
+      template <class M>
+      iterator insert_or_assign(const_iterator, key_type const& key, M&& obj)
+      {
+        return this->insert_or_assign(key, std::forward<M>(obj)).first;
+      }
+
+      template <class M>
+      iterator insert_or_assign(const_iterator, key_type&& key, M&& obj)
+      {
+        return this->insert_or_assign(std::move(key), std::forward<M>(obj))
+          .first;
+      }
+
+      template <class... Args>
+      BOOST_FORCEINLINE std::pair<iterator, bool> emplace(Args&&... args)
+      {
+        return table_.emplace(std::forward<Args>(args)...);
+      }
+
+      template <class... Args>
+      BOOST_FORCEINLINE iterator emplace_hint(const_iterator, Args&&... args)
+      {
+        return table_.emplace(std::forward<Args>(args)...).first;
+      }
+
+      template <class... Args>
+      BOOST_FORCEINLINE std::pair<iterator, bool> try_emplace(
+        key_type const& key, Args&&... args)
+      {
+        return table_.try_emplace(key, std::forward<Args>(args)...);
+      }
+
+      template <class... Args>
+      BOOST_FORCEINLINE std::pair<iterator, bool> try_emplace(
+        key_type&& key, Args&&... args)
+      {
+        return table_.try_emplace(std::move(key), std::forward<Args>(args)...);
+      }
+
+      template <class... Args>
+      BOOST_FORCEINLINE iterator try_emplace(
+        const_iterator, key_type const& key, Args&&... args)
+      {
+        return table_.try_emplace(key, std::forward<Args>(args)...).first;
+      }
+
+      template <class... Args>
+      BOOST_FORCEINLINE iterator try_emplace(
+        const_iterator, key_type&& key, Args&&... args)
+      {
+        return table_.try_emplace(std::move(key), std::forward<Args>(args)...)
+          .first;
+      }
+
+      BOOST_FORCEINLINE void erase(iterator pos) { table_.erase(pos); }
+      BOOST_FORCEINLINE void erase(const_iterator pos)
+      {
+        return table_.erase(pos);
+      }
+      iterator erase(const_iterator first, const_iterator last)
+      {
+        while (first != last) {
+          this->erase(first++);
+        }
+        return iterator{detail::foa::const_iterator_cast_tag{}, last};
+      }
+
+      BOOST_FORCEINLINE size_type erase(key_type const& key)
+      {
+        return table_.erase(key);
+      }
+
+      template <class K>
+      BOOST_FORCEINLINE typename std::enable_if<
+        detail::transparent_non_iterable<K, unordered_flat_map>::value,
+        size_type>::type
+      erase(K const& key)
+      {
+        return table_.erase(key);
+      }
+
+      void swap(unordered_flat_map& rhs) noexcept(
+        noexcept(std::declval<table_type&>().swap(std::declval<table_type&>())))
+      {
+        table_.swap(rhs.table_);
+      }
+
+      template <class H2, class P2>
+      void merge(
+        unordered_flat_map<key_type, mapped_type, H2, P2, allocator_type>&
+          source)
+      {
+        table_.merge(source.table_);
+      }
+
+      template <class H2, class P2>
+      void merge(
+        unordered_flat_map<key_type, mapped_type, H2, P2, allocator_type>&&
+          source)
+      {
+        table_.merge(std::move(source.table_));
+      }
+
+      /// Lookup
+      ///
+
+      mapped_type& at(key_type const& key)
+      {
+        auto pos = table_.find(key);
+        if (pos != table_.end()) {
+          return pos->second;
+        }
+        // TODO: someday refactor this to conditionally serialize the key and
+        // include it in the error message
+        //
+        boost::throw_exception(
+          std::out_of_range("key was not found in unordered_flat_map"));
+      }
+
+      mapped_type const& at(key_type const& key) const
+      {
+        auto pos = table_.find(key);
+        if (pos != table_.end()) {
+          return pos->second;
+        }
+        boost::throw_exception(
+          std::out_of_range("key was not found in unordered_flat_map"));
+      }
+
+      mapped_type& operator[](key_type const& key)
+      {
+        return table_.try_emplace(key).first->second;
+      }
+
+      mapped_type& operator[](key_type&& key)
+      {
+        return table_.try_emplace(std::move(key)).first->second;
+      }
+
+      size_type count(key_type const& key) const
+      {
+        auto pos = table_.find(key);
+        return pos != table_.end() ? 1 : 0;
+      }
+
+      template <class K>
+      typename std::enable_if<
+        detail::are_transparent<K, hasher, key_equal>::value, size_type>::type
+      count(K const& key) const
+      {
+        auto pos = table_.find(key);
+        return pos != table_.end() ? 1 : 0;
+      }
+
+      BOOST_FORCEINLINE iterator find(key_type const& key)
+      {
+        return table_.find(key);
+      }
+
+      BOOST_FORCEINLINE const_iterator find(key_type const& key) const
+      {
+        return table_.find(key);
+      }
+
+      template <class K>
+      BOOST_FORCEINLINE typename std::enable_if<
+        boost::unordered::detail::are_transparent<K, hasher, key_equal>::value,
+        iterator>::type
+      find(K const& key)
+      {
+        return table_.find(key);
+      }
+
+      template <class K>
+      BOOST_FORCEINLINE typename std::enable_if<
+        boost::unordered::detail::are_transparent<K, hasher, key_equal>::value,
+        const_iterator>::type
+      find(K const& key) const
+      {
+        return table_.find(key);
+      }
+
+      bool contains(key_type const& key) const
+      {
+        return this->find(key) != this->end();
+      }
+
+      template <class K>
+      typename std::enable_if<
+        boost::unordered::detail::are_transparent<K, hasher, key_equal>::value,
+        bool>::type
+      contains(K const& key) const
+      {
+        return this->find(key) != this->end();
+      }
+
+      std::pair<iterator, iterator> equal_range(key_type const& key)
+      {
+        auto pos = table_.find(key);
+        if (pos == table_.end()) {
+          return {pos, pos};
+        }
+
+        auto next = pos;
+        ++next;
+        return {pos, next};
+      }
+
+      std::pair<const_iterator, const_iterator> equal_range(
+        key_type const& key) const
+      {
+        auto pos = table_.find(key);
+        if (pos == table_.end()) {
+          return {pos, pos};
+        }
+
+        auto next = pos;
+        ++next;
+        return {pos, next};
+      }
+
+      template <class K>
+      typename std::enable_if<
+        detail::are_transparent<K, hasher, key_equal>::value,
+        std::pair<iterator, iterator> >::type
+      equal_range(K const& key)
+      {
+        auto pos = table_.find(key);
+        if (pos == table_.end()) {
+          return {pos, pos};
+        }
+
+        auto next = pos;
+        ++next;
+        return {pos, next};
+      }
+
+      template <class K>
+      typename std::enable_if<
+        detail::are_transparent<K, hasher, key_equal>::value,
+        std::pair<const_iterator, const_iterator> >::type
+      equal_range(K const& key) const
+      {
+        auto pos = table_.find(key);
+        if (pos == table_.end()) {
+          return {pos, pos};
+        }
+
+        auto next = pos;
+        ++next;
+        return {pos, next};
+      }
+
+      /// Hash Policy
+      ///
+
+      size_type bucket_count() const noexcept { return table_.capacity(); }
+
+      float load_factor() const noexcept { return table_.load_factor(); }
+
+      float max_load_factor() const noexcept
+      {
+        return table_.max_load_factor();
+      }
+
+      void max_load_factor(float) {}
+
+      void rehash(size_type n) { table_.rehash(n); }
+
+      void reserve(size_type n) { table_.reserve(n); }
+
+      /// Observers
+      ///
+
+      hasher hash_function() const { return table_.hash_function(); }
+
+      key_equal key_eq() const { return table_.key_eq(); }
+    };
+
+    template <class Key, class T, class Hash, class KeyEqual, class Allocator>
+    bool operator==(
+      unordered_flat_map<Key, T, Hash, KeyEqual, Allocator> const& lhs,
+      unordered_flat_map<Key, T, Hash, KeyEqual, Allocator> const& rhs)
+    {
+      if (&lhs == &rhs) {
+        return true;
+      }
+
+      return (lhs.size() == rhs.size()) && ([&] {
+        for (auto const& kvp : lhs) {
+          auto pos = rhs.find(kvp.first);
+          if ((pos == rhs.end()) || (*pos != kvp)) {
+            return false;
+          }
+        }
+        return true;
+      })();
+    }
+
+    template <class Key, class T, class Hash, class KeyEqual, class Allocator>
+    bool operator!=(
+      unordered_flat_map<Key, T, Hash, KeyEqual, Allocator> const& lhs,
+      unordered_flat_map<Key, T, Hash, KeyEqual, Allocator> const& rhs)
+    {
+      return !(lhs == rhs);
+    }
+
+    template <class Key, class T, class Hash, class KeyEqual, class Allocator>
+    void swap(unordered_flat_map<Key, T, Hash, KeyEqual, Allocator>& lhs,
+      unordered_flat_map<Key, T, Hash, KeyEqual, Allocator>& rhs)
+      noexcept(noexcept(lhs.swap(rhs)))
+    {
+      lhs.swap(rhs);
+    }
+
+    template <class Key, class T, class Hash, class KeyEqual, class Allocator,
+      class Pred>
+    typename unordered_flat_map<Key, T, Hash, KeyEqual, Allocator>::size_type
+    erase_if(
+      unordered_flat_map<Key, T, Hash, KeyEqual, Allocator>& map, Pred pred)
+    {
+      return erase_if(map.table_, pred);
+    }
+
+#if defined(BOOST_MSVC)
+#pragma warning(pop) /* C4714 */
+#endif
+
+  } // namespace unordered
+} // namespace boost
+
+#endif

include/boost/unordered/unordered_flat_map_fwd.hpp

@@ -0,0 +1,49 @@
+
+// Copyright (C) 2022 Christian Mazakas
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+
+#ifndef BOOST_UNORDERED_FLAT_MAP_FWD_HPP_INCLUDED
+#define BOOST_UNORDERED_FLAT_MAP_FWD_HPP_INCLUDED
+
+#include <boost/config.hpp>
+#if defined(BOOST_HAS_PRAGMA_ONCE)
+#pragma once
+#endif
+
+#include <boost/functional/hash_fwd.hpp>
+#include <boost/unordered/detail/fwd.hpp>
+#include <functional>
+#include <memory>
+
+namespace boost {
+  namespace unordered {
+    template <class Key, class T, class Hash = boost::hash<Key>,
+      class KeyEqual = std::equal_to<Key>,
+      class Allocator = std::allocator<std::pair<const Key, T> > >
+    class unordered_flat_map;
+
+    template <class Key, class T, class Hash, class KeyEqual, class Allocator>
+    bool operator==(
+      unordered_flat_map<Key, T, Hash, KeyEqual, Allocator> const& lhs,
+      unordered_flat_map<Key, T, Hash, KeyEqual, Allocator> const& rhs);
+
+    template <class Key, class T, class Hash, class KeyEqual, class Allocator>
+    bool operator!=(
+      unordered_flat_map<Key, T, Hash, KeyEqual, Allocator> const& lhs,
+      unordered_flat_map<Key, T, Hash, KeyEqual, Allocator> const& rhs);
+
+    template <class Key, class T, class Hash, class KeyEqual, class Allocator>
+    void swap(unordered_flat_map<Key, T, Hash, KeyEqual, Allocator>& lhs,
+      unordered_flat_map<Key, T, Hash, KeyEqual, Allocator>& rhs)
+      noexcept(noexcept(lhs.swap(rhs)));
+  } // namespace unordered
+
+  using boost::unordered::unordered_flat_map;
+
+  using boost::unordered::swap;
+  using boost::unordered::operator==;
+  using boost::unordered::operator!=;
+} // namespace boost
+
+#endif

include/boost/unordered/unordered_flat_set.hpp

@@ -0,0 +1,494 @@
+// Copyright (C) 2022 Christian Mazakas
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+
+#ifndef BOOST_UNORDERED_UNORDERED_FLAT_SET_HPP_INCLUDED
+#define BOOST_UNORDERED_UNORDERED_FLAT_SET_HPP_INCLUDED
+
+#include <boost/config.hpp>
+#if defined(BOOST_HAS_PRAGMA_ONCE)
+#pragma once
+#endif
+
+#include <boost/unordered/detail/foa.hpp>
+#include <boost/unordered/detail/type_traits.hpp>
+#include <boost/unordered/unordered_flat_set_fwd.hpp>
+
+#include <boost/core/allocator_access.hpp>
+#include <boost/functional/hash.hpp>
+
+#include <initializer_list>
+#include <iterator>
+#include <type_traits>
+#include <utility>
+
+namespace boost {
+  namespace unordered {
+
+#if defined(BOOST_MSVC)
+#pragma warning(push)
+#pragma warning(disable : 4714) /* marked as __forceinline not inlined */
+#endif
+
+    template <class Key, class Hash, class KeyEqual, class Allocator>
+    class unordered_flat_set
+    {
+      struct set_types
+      {
+        using key_type = Key;
+        using init_type = Key;
+        using value_type = Key;
+        static Key const& extract(value_type const& key) { return key; }
+        static Key&& move(value_type& x) { return std::move(x); }
+      };
+
+      using table_type = detail::foa::table<set_types, Hash, KeyEqual,
+        typename boost::allocator_rebind<Allocator,
+          typename set_types::value_type>::type>;
+
+      table_type table_;
+
+      template <class K, class H, class KE, class A, class Pred>
+      typename unordered_flat_set<K, H, KE, A>::size_type friend erase_if(
+        unordered_flat_set<K, H, KE, A>& set, Pred pred);
+
+    public:
+      using key_type = Key;
+      using value_type = typename set_types::value_type;
+      using init_type = typename set_types::init_type;
+      using size_type = std::size_t;
+      using difference_type = std::ptrdiff_t;
+      using hasher = Hash;
+      using key_equal = KeyEqual;
+      using allocator_type = Allocator;
+      using reference = value_type&;
+      using const_reference = value_type const&;
+      using pointer = typename boost::allocator_pointer<allocator_type>::type;
+      using const_pointer =
+        typename boost::allocator_const_pointer<allocator_type>::type;
+      using iterator = typename table_type::iterator;
+      using const_iterator = typename table_type::const_iterator;
+
+      unordered_flat_set() : unordered_flat_set(0) {}
+
+      explicit unordered_flat_set(size_type n, hasher const& h = hasher(),
+        key_equal const& pred = key_equal(),
+        allocator_type const& a = allocator_type())
+          : table_(n, h, pred, a)
+      {
+      }
+
+      unordered_flat_set(size_type n, allocator_type const& a)
+          : unordered_flat_set(n, hasher(), key_equal(), a)
+      {
+      }
+
+      unordered_flat_set(size_type n, hasher const& h, allocator_type const& a)
+          : unordered_flat_set(n, h, key_equal(), a)
+      {
+      }
+
+      explicit unordered_flat_set(allocator_type const& a)
+          : unordered_flat_set(0, a)
+      {
+      }
+
+      template <class Iterator>
+      unordered_flat_set(Iterator first, Iterator last, size_type n = 0,
+        hasher const& h = hasher(), key_equal const& pred = key_equal(),
+        allocator_type const& a = allocator_type())
+          : unordered_flat_set(n, h, pred, a)
+      {
+        this->insert(first, last);
+      }
+
+      template <class InputIt>
+      unordered_flat_set(
+        InputIt first, InputIt last, size_type n, allocator_type const& a)
+          : unordered_flat_set(first, last, n, hasher(), key_equal(), a)
+      {
+      }
+
+      template <class Iterator>
+      unordered_flat_set(Iterator first, Iterator last, size_type n,
+        hasher const& h, allocator_type const& a)
+          : unordered_flat_set(first, last, n, h, key_equal(), a)
+      {
+      }
+
+      unordered_flat_set(unordered_flat_set const& other) : table_(other.table_)
+      {
+      }
+
+      unordered_flat_set(
+        unordered_flat_set const& other, allocator_type const& a)
+          : table_(other.table_, a)
+      {
+      }
+
+      unordered_flat_set(unordered_flat_set&& other)
+        noexcept(std::is_nothrow_move_constructible<hasher>::value&&
+            std::is_nothrow_move_constructible<key_equal>::value&&
+              std::is_nothrow_move_constructible<allocator_type>::value)
+          : table_(std::move(other.table_))
+      {
+      }
+
+      unordered_flat_set(unordered_flat_set&& other, allocator_type const& al)
+          : table_(std::move(other.table_), al)
+      {
+      }
+
+      unordered_flat_set(std::initializer_list<value_type> ilist,
+        size_type n = 0, hasher const& h = hasher(),
+        key_equal const& pred = key_equal(),
+        allocator_type const& a = allocator_type())
+          : unordered_flat_set(ilist.begin(), ilist.end(), n, h, pred, a)
+      {
+      }
+
+      unordered_flat_set(std::initializer_list<value_type> init, size_type n,
+        allocator_type const& a)
+          : unordered_flat_set(init, n, hasher(), key_equal(), a)
+      {
+      }
+
+      unordered_flat_set(std::initializer_list<value_type> init, size_type n,
+        hasher const& h, allocator_type const& a)
+          : unordered_flat_set(init, n, h, key_equal(), a)
+      {
+      }
+
+      ~unordered_flat_set() = default;
+
+      unordered_flat_set& operator=(unordered_flat_set const& other)
+      {
+        table_ = other.table_;
+        return *this;
+      }
+
+      unordered_flat_set& operator=(unordered_flat_set&& other) noexcept(
+        noexcept(std::declval<table_type&>() = std::declval<table_type&&>()))
+      {
+        table_ = std::move(other.table_);
+        return *this;
+      }
+
+      allocator_type get_allocator() const noexcept
+      {
+        return table_.get_allocator();
+      }
+
+      /// Iterators
+      ///
+
+      iterator begin() noexcept { return table_.begin(); }
+      const_iterator begin() const noexcept { return table_.begin(); }
+      const_iterator cbegin() const noexcept { return table_.cbegin(); }
+
+      iterator end() noexcept { return table_.end(); }
+      const_iterator end() const noexcept { return table_.end(); }
+      const_iterator cend() const noexcept { return table_.cend(); }
+
+      /// Capacity
+      ///
+
+      BOOST_ATTRIBUTE_NODISCARD bool empty() const noexcept
+      {
+        return table_.empty();
+      }
+
+      size_type size() const noexcept { return table_.size(); }
+
+      size_type max_size() const noexcept { return table_.max_size(); }
+
+      /// Modifiers
+      ///
+
+      void clear() noexcept { table_.clear(); }
+
+      BOOST_FORCEINLINE std::pair<iterator, bool> insert(
+        value_type const& value)
+      {
+        return table_.insert(value);
+      }
+
+      BOOST_FORCEINLINE std::pair<iterator, bool> insert(value_type&& value)
+      {
+        return table_.insert(std::move(value));
+      }
+
+      BOOST_FORCEINLINE iterator insert(const_iterator, value_type const& value)
+      {
+        return table_.insert(value).first;
+      }
+
+      BOOST_FORCEINLINE iterator insert(const_iterator, value_type&& value)
+      {
+        return table_.insert(std::move(value)).first;
+      }
+
+      template <class InputIterator>
+      void insert(InputIterator first, InputIterator last)
+      {
+        for (auto pos = first; pos != last; ++pos) {
+          table_.emplace(*pos);
+        }
+      }
+
+      void insert(std::initializer_list<value_type> ilist)
+      {
+        this->insert(ilist.begin(), ilist.end());
+      }
+
+      template <class... Args>
+      BOOST_FORCEINLINE std::pair<iterator, bool> emplace(Args&&... args)
+      {
+        return table_.emplace(std::forward<Args>(args)...);
+      }
+
+      template <class... Args>
+      BOOST_FORCEINLINE iterator emplace_hint(const_iterator, Args&&... args)
+      {
+        return table_.emplace(std::forward<Args>(args)...).first;
+      }
+
+      BOOST_FORCEINLINE void erase(const_iterator pos)
+      {
+        return table_.erase(pos);
+      }
+      iterator erase(const_iterator first, const_iterator last)
+      {
+        while (first != last) {
+          this->erase(first++);
+        }
+        return iterator{detail::foa::const_iterator_cast_tag{}, last};
+      }
+
+      BOOST_FORCEINLINE size_type erase(key_type const& key)
+      {
+        return table_.erase(key);
+      }
+
+      template <class K>
+      BOOST_FORCEINLINE typename std::enable_if<
+        detail::transparent_non_iterable<K, unordered_flat_set>::value,
+        size_type>::type
+      erase(K const& key)
+      {
+        return table_.erase(key);
+      }
+
+      void swap(unordered_flat_set& rhs) noexcept(
+        noexcept(std::declval<table_type&>().swap(std::declval<table_type&>())))
+      {
+        table_.swap(rhs.table_);
+      }
+
+      template <class H2, class P2>
+      void merge(unordered_flat_set<key_type, H2, P2, allocator_type>& source)
+      {
+        table_.merge(source.table_);
+      }
+
+      template <class H2, class P2>
+      void merge(unordered_flat_set<key_type, H2, P2, allocator_type>&& source)
+      {
+        table_.merge(std::move(source.table_));
+      }
+
+      /// Lookup
+      ///
+
+      size_type count(key_type const& key) const
+      {
+        auto pos = table_.find(key);
+        return pos != table_.end() ? 1 : 0;
+      }
+
+      template <class K>
+      typename std::enable_if<
+        detail::are_transparent<K, hasher, key_equal>::value, size_type>::type
+      count(K const& key) const
+      {
+        auto pos = table_.find(key);
+        return pos != table_.end() ? 1 : 0;
+      }
+
+      BOOST_FORCEINLINE iterator find(key_type const& key)
+      {
+        return table_.find(key);
+      }
+
+      BOOST_FORCEINLINE const_iterator find(key_type const& key) const
+      {
+        return table_.find(key);
+      }
+
+      template <class K>
+      BOOST_FORCEINLINE typename std::enable_if<
+        boost::unordered::detail::are_transparent<K, hasher, key_equal>::value,
+        iterator>::type
+      find(K const& key)
+      {
+        return table_.find(key);
+      }
+
+      template <class K>
+      BOOST_FORCEINLINE typename std::enable_if<
+        boost::unordered::detail::are_transparent<K, hasher, key_equal>::value,
+        const_iterator>::type
+      find(K const& key) const
+      {
+        return table_.find(key);
+      }
+
+      bool contains(key_type const& key) const
+      {
+        return this->find(key) != this->end();
+      }
+
+      template <class K>
+      typename std::enable_if<
+        boost::unordered::detail::are_transparent<K, hasher, key_equal>::value,
+        bool>::type
+      contains(K const& key) const
+      {
+        return this->find(key) != this->end();
+      }
+
+      std::pair<iterator, iterator> equal_range(key_type const& key)
+      {
+        auto pos = table_.find(key);
+        if (pos == table_.end()) {
+          return {pos, pos};
+        }
+
+        auto next = pos;
+        ++next;
+        return {pos, next};
+      }
+
+      std::pair<const_iterator, const_iterator> equal_range(
+        key_type const& key) const
+      {
+        auto pos = table_.find(key);
+        if (pos == table_.end()) {
+          return {pos, pos};
+        }
+
+        auto next = pos;
+        ++next;
+        return {pos, next};
+      }
+
+      template <class K>
+      typename std::enable_if<
+        detail::are_transparent<K, hasher, key_equal>::value,
+        std::pair<iterator, iterator> >::type
+      equal_range(K const& key)
+      {
+        auto pos = table_.find(key);
+        if (pos == table_.end()) {
+          return {pos, pos};
+        }
+
+        auto next = pos;
+        ++next;
+        return {pos, next};
+      }
+
+      template <class K>
+      typename std::enable_if<
+        detail::are_transparent<K, hasher, key_equal>::value,
+        std::pair<const_iterator, const_iterator> >::type
+      equal_range(K const& key) const
+      {
+        auto pos = table_.find(key);
+        if (pos == table_.end()) {
+          return {pos, pos};
+        }
+
+        auto next = pos;
+        ++next;
+        return {pos, next};
+      }
+
+      /// Hash Policy
+      ///
+
+      size_type bucket_count() const noexcept { return table_.capacity(); }
+
+      float load_factor() const noexcept { return table_.load_factor(); }
+
+      float max_load_factor() const noexcept
+      {
+        return table_.max_load_factor();
+      }
+
+      void max_load_factor(float) {}
+
+      void rehash(size_type n) { table_.rehash(n); }
+
+      void reserve(size_type n) { table_.reserve(n); }
+
+      /// Observers
+      ///
+
+      hasher hash_function() const { return table_.hash_function(); }
+
+      key_equal key_eq() const { return table_.key_eq(); }
+    };
+
+    template <class Key, class Hash, class KeyEqual, class Allocator>
+    bool operator==(
+      unordered_flat_set<Key, Hash, KeyEqual, Allocator> const& lhs,
+      unordered_flat_set<Key, Hash, KeyEqual, Allocator> const& rhs)
+    {
+      if (&lhs == &rhs) {
+        return true;
+      }
+
+      return (lhs.size() == rhs.size()) && ([&] {
+        for (auto const& key : lhs) {
+          auto pos = rhs.find(key);
+          if ((pos == rhs.end()) || (key != *pos)) {
+            return false;
+          }
+        }
+        return true;
+      })();
+    }
+
+    template <class Key, class Hash, class KeyEqual, class Allocator>
+    bool operator!=(
+      unordered_flat_set<Key, Hash, KeyEqual, Allocator> const& lhs,
+      unordered_flat_set<Key, Hash, KeyEqual, Allocator> const& rhs)
+    {
+      return !(lhs == rhs);
+    }
+
+    template <class Key, class Hash, class KeyEqual, class Allocator>
+    void swap(unordered_flat_set<Key, Hash, KeyEqual, Allocator>& lhs,
+      unordered_flat_set<Key, Hash, KeyEqual, Allocator>& rhs)
+      noexcept(noexcept(lhs.swap(rhs)))
+    {
+      lhs.swap(rhs);
+    }
+
+    template <class Key, class Hash, class KeyEqual, class Allocator,
+      class Pred>
+    typename unordered_flat_set<Key, Hash, KeyEqual, Allocator>::size_type
+    erase_if(unordered_flat_set<Key, Hash, KeyEqual, Allocator>& set, Pred pred)
+    {
+      return erase_if(set.table_, pred);
+    }
+
+#if defined(BOOST_MSVC)
+#pragma warning(pop) /* C4714 */
+#endif
+
+  } // namespace unordered
+} // namespace boost
+
+#endif

include/boost/unordered/unordered_flat_set_fwd.hpp

@@ -0,0 +1,49 @@
+
+// Copyright (C) 2022 Christian Mazakas
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+
+#ifndef BOOST_UNORDERED_FLAT_SET_FWD_HPP_INCLUDED
+#define BOOST_UNORDERED_FLAT_SET_FWD_HPP_INCLUDED
+
+#include <boost/config.hpp>
+#if defined(BOOST_HAS_PRAGMA_ONCE)
+#pragma once
+#endif
+
+#include <boost/functional/hash_fwd.hpp>
+#include <boost/unordered/detail/fwd.hpp>
+#include <functional>
+#include <memory>
+
+namespace boost {
+  namespace unordered {
+    template <class Key, class Hash = boost::hash<Key>,
+      class KeyEqual = std::equal_to<Key>,
+      class Allocator = std::allocator<Key> >
+    class unordered_flat_set;
+
+    template <class Key, class Hash, class KeyEqual, class Allocator>
+    bool operator==(
+      unordered_flat_set<Key, Hash, KeyEqual, Allocator> const& lhs,
+      unordered_flat_set<Key, Hash, KeyEqual, Allocator> const& rhs);
+
+    template <class Key, class Hash, class KeyEqual, class Allocator>
+    bool operator!=(
+      unordered_flat_set<Key, Hash, KeyEqual, Allocator> const& lhs,
+      unordered_flat_set<Key, Hash, KeyEqual, Allocator> const& rhs);
+
+    template <class Key, class Hash, class KeyEqual, class Allocator>
+    void swap(unordered_flat_set<Key, Hash, KeyEqual, Allocator>& lhs,
+      unordered_flat_set<Key, Hash, KeyEqual, Allocator>& rhs)
+      noexcept(noexcept(lhs.swap(rhs)));
+  } // namespace unordered
+
+  using boost::unordered::unordered_flat_set;
+
+  using boost::unordered::swap;
+  using boost::unordered::operator==;
+  using boost::unordered::operator!=;
+} // namespace boost
+
+#endif

include/boost/unordered/unordered_map.hpp

@@ -1,6 +1,7 @@
 
 // Copyright (C) 2003-2004 Jeremy B. Maitin-Shepard.
 // Copyright (C) 2005-2011 Daniel James.
+// Copyright (C) 2022 Christian Mazakas
 // Distributed under the Boost Software License, Version 1.0. (See accompanying
 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
 
@@ -57,8 +58,6 @@ namespace boost {
       typedef boost::unordered::detail::map<A, K, T, H, P> types;
       typedef typename types::value_allocator_traits value_allocator_traits;
       typedef typename types::table table;
-      typedef typename table::node_pointer node_pointer;
-      typedef typename table::link_pointer link_pointer;
 
     public:
       typedef typename value_allocator_traits::pointer pointer;
@@ -97,7 +96,7 @@ namespace boost {
 
       unordered_map(unordered_map const&);
 
-#if defined(BOOST_UNORDERED_USE_MOVE) ||                                       \
+#if defined(BOOST_UNORDERED_USE_MOVE) ||                                        \
   !defined(BOOST_NO_CXX11_RVALUE_REFERENCES)
       unordered_map(BOOST_RV_REF(unordered_map) other)
         BOOST_NOEXCEPT_IF(table::nothrow_move_constructible)
@@ -188,9 +187,9 @@ namespace boost {
         return table_.node_alloc();
       }
 
-      // iterators
+//       // iterators
 
-      iterator begin() BOOST_NOEXCEPT { return iterator(table_.begin()); }
+      iterator begin() BOOST_NOEXCEPT { return table_.begin(); }
 
       const_iterator begin() const BOOST_NOEXCEPT
       {
@@ -445,7 +444,7 @@ namespace boost {
       insert_return_type insert(BOOST_RV_REF(node_type) np)
       {
         insert_return_type result;
-        table_.move_insert_node_type_unique(np, result);
+        table_.move_insert_node_type_unique((node_type&)np, result);
         return boost::move(result);
       }
 
@@ -728,8 +727,7 @@ namespace boost {
         size_type>::type
       erase(BOOST_FWD_REF(Key) k)
       {
-        return table_.erase_key_unique_impl(
-          this->key_eq(), boost::forward<Key>(k));
+        return table_.erase_key_unique_impl(boost::forward<Key>(k));
       }
 
       BOOST_UNORDERED_DEPRECATED("Use erase instead")
@@ -774,9 +772,7 @@ namespace boost {
         iterator>::type
       find(const Key& key)
       {
-        return iterator(table_.find_node_impl(
-          table::policy::apply_hash(this->hash_function(), key), key,
-          this->key_eq()));
+        return table_.find(key);
       }
 
       template <class Key>
@@ -784,9 +780,7 @@ namespace boost {
         const_iterator>::type
       find(const Key& key) const
       {
-        return const_iterator(table_.find_node_impl(
-          table::policy::apply_hash(this->hash_function(), key), key,
-          this->key_eq()));
+        return const_iterator(table_.find(key));
       }
 
       template <class CompatibleKey, class CompatibleHash,
@@ -801,9 +795,7 @@ namespace boost {
 
       bool contains(const key_type& k) const
       {
-        return 0 != table_.find_node_impl(
-                      table::policy::apply_hash(this->hash_function(), k), k,
-                      this->key_eq());
+        return table_.find(k) != this->end();
       }
 
       template <class Key>
@@ -811,9 +803,7 @@ namespace boost {
         bool>::type
       contains(const Key& k) const
       {
-        return 0 != table_.find_node_impl(
-                      table::policy::apply_hash(this->hash_function(), k), k,
-                      this->key_eq());
+        return table_.find(k) != this->end();
       }
 
       size_type count(const key_type&) const;
@@ -823,14 +813,7 @@ namespace boost {
         size_type>::type
       count(const Key& k) const
       {
-        std::size_t const key_hash =
-          table::policy::apply_hash(this->hash_function(), k);
-
-        P const& eq = this->key_eq();
-
-        node_pointer p = table_.find_node_impl(key_hash, k, eq);
-
-        return (p ? 1 : 0);
+        return (table_.find(k) != this->end() ? 1 : 0);
       }
 
       std::pair<iterator, iterator> equal_range(const key_type&);
@@ -842,12 +825,13 @@ namespace boost {
         std::pair<iterator, iterator> >::type
       equal_range(const Key& key)
       {
-        node_pointer p = table_.find_node_impl(
-          table::policy::apply_hash(this->hash_function(), key), key,
-          this->key_eq());
+        iterator first = table_.find(key);
+        iterator last = first;
+        if (last != this->end()) {
+          ++last;
+        }
 
-        return std::make_pair(
-          iterator(p), iterator(p ? table::next_node(p) : p));
+        return std::make_pair(first, last);
       }
 
       template <class Key>
@@ -855,12 +839,13 @@ namespace boost {
         std::pair<const_iterator, const_iterator> >::type
       equal_range(const Key& key) const
       {
-        node_pointer p = table_.find_node_impl(
-          table::policy::apply_hash(this->hash_function(), key), key,
-          this->key_eq());
+        iterator first = table_.find(key);
+        iterator last = first;
+        if (last != this->end()) {
+          ++last;
+        }
 
-        return std::make_pair(
-          const_iterator(p), const_iterator(p ? table::next_node(p) : p));
+        return std::make_pair(first, last);
       }
 
       mapped_type& operator[](const key_type&);
@@ -872,7 +857,7 @@ namespace boost {
 
       size_type bucket_count() const BOOST_NOEXCEPT
       {
-        return table_.bucket_count_;
+        return table_.bucket_count();
       }
 
       size_type max_bucket_count() const BOOST_NOEXCEPT
@@ -889,16 +874,15 @@ namespace boost {
 
       local_iterator begin(size_type n)
       {
-        return local_iterator(table_.begin(n), n, table_.bucket_count_);
+        return table_.begin(n);
       }
 
       const_local_iterator begin(size_type n) const
       {
-        return const_local_iterator(table_.begin(n), n, table_.bucket_count_);
+        return const_local_iterator(table_.begin(n));
       }
 
       local_iterator end(size_type) { return local_iterator(); }
-
       const_local_iterator end(size_type) const
       {
         return const_local_iterator();
@@ -906,7 +890,7 @@ namespace boost {
 
       const_local_iterator cbegin(size_type n) const
       {
-        return const_local_iterator(table_.begin(n), n, table_.bucket_count_);
+        return const_local_iterator(table_.begin(n));
       }
 
       const_local_iterator cend(size_type) const
@@ -1026,8 +1010,6 @@ namespace boost {
       typedef boost::unordered::detail::map<A, K, T, H, P> types;
       typedef typename types::value_allocator_traits value_allocator_traits;
       typedef typename types::table table;
-      typedef typename table::node_pointer node_pointer;
-      typedef typename table::link_pointer link_pointer;
 
     public:
       typedef typename value_allocator_traits::pointer pointer;
@@ -1394,7 +1376,7 @@ namespace boost {
 
       node_type extract(const key_type& k)
       {
-        return node_type(table_.extract_by_key(k), table_.node_alloc());
+        return node_type(table_.extract_by_key_impl(k), table_.node_alloc());
       }
 
       template <class Key>
@@ -1437,8 +1419,7 @@ namespace boost {
         size_type>::type
       erase(BOOST_FWD_REF(Key) k)
       {
-        return table_.erase_key_equiv_impl(
-          this->key_eq(), boost::forward<Key>(k));
+        return table_.erase_key_equiv_impl(boost::forward<Key>(k));
       }
 
       BOOST_UNORDERED_DEPRECATED("Use erase instead")
@@ -1483,9 +1464,7 @@ namespace boost {
         iterator>::type
       find(const Key& key)
       {
-        return iterator(table_.find_node_impl(
-          table::policy::apply_hash(this->hash_function(), key), key,
-          this->key_eq()));
+        return table_.find(key);
       }
 
       template <class Key>
@@ -1493,9 +1472,7 @@ namespace boost {
         const_iterator>::type
       find(const Key& key) const
       {
-        return const_iterator(table_.find_node_impl(
-          table::policy::apply_hash(this->hash_function(), key), key,
-          this->key_eq()));
+        return const_iterator(table_.find(key));
       }
 
       template <class CompatibleKey, class CompatibleHash,
@@ -1510,9 +1487,7 @@ namespace boost {
 
       bool contains(key_type const& k) const
       {
-        return 0 != table_.find_node_impl(
-                      table::policy::apply_hash(this->hash_function(), k), k,
-                      this->key_eq());
+        return table_.find(k) != this->end();
       }
 
       template <class Key>
@@ -1520,9 +1495,7 @@ namespace boost {
         bool>::type
       contains(const Key& k) const
       {
-        return 0 != table_.find_node_impl(
-                      table::policy::apply_hash(this->hash_function(), k), k,
-                      this->key_eq());
+        return table_.find(k) != this->end();
       }
 
       size_type count(const key_type&) const;
@@ -1532,11 +1505,7 @@ namespace boost {
         size_type>::type
       count(const Key& k) const
       {
-        node_pointer n = table_.find_node_impl(
-          table::policy::apply_hash(this->hash_function(), k), k,
-          this->key_eq());
-
-        return n ? table_.group_count(n) : 0;
+        return table_.group_count(k);
       }
 
       std::pair<iterator, iterator> equal_range(const key_type&);
@@ -1548,12 +1517,8 @@ namespace boost {
         std::pair<iterator, iterator> >::type
       equal_range(const Key& key)
       {
-        node_pointer p = table_.find_node_impl(
-          table::policy::apply_hash(this->hash_function(), key), key,
-          this->key_eq());
-
-        return std::make_pair(
-          iterator(p), iterator(p ? table_.next_group(p) : p));
+        iterator p = table_.find(key);
+        return std::make_pair(p, table_.next_group(key, p));
       }
 
       template <class Key>
@@ -1561,19 +1526,16 @@ namespace boost {
         std::pair<const_iterator, const_iterator> >::type
       equal_range(const Key& key) const
       {
-        node_pointer p = table_.find_node_impl(
-          table::policy::apply_hash(this->hash_function(), key), key,
-          this->key_eq());
-
+        iterator p = table_.find(key);
         return std::make_pair(
-          const_iterator(p), const_iterator(p ? table_.next_group(p) : p));
+          const_iterator(p), const_iterator(table_.next_group(key, p)));
       }
 
       // bucket interface
 
       size_type bucket_count() const BOOST_NOEXCEPT
       {
-        return table_.bucket_count_;
+        return table_.bucket_count();
       }
 
       size_type max_bucket_count() const BOOST_NOEXCEPT
@@ -1590,12 +1552,12 @@ namespace boost {
 
       local_iterator begin(size_type n)
       {
-        return local_iterator(table_.begin(n), n, table_.bucket_count_);
+        return local_iterator(table_.begin(n));
       }
 
       const_local_iterator begin(size_type n) const
       {
-        return const_local_iterator(table_.begin(n), n, table_.bucket_count_);
+        return const_local_iterator(table_.begin(n));
       }
 
       local_iterator end(size_type) { return local_iterator(); }
@@ -1607,7 +1569,7 @@ namespace boost {
 
       const_local_iterator cbegin(size_type n) const
       {
-        return const_local_iterator(table_.begin(n), n, table_.bucket_count_);
+        return const_local_iterator(table_.begin(n));
       }
 
       const_local_iterator cend(size_type) const
@@ -1702,8 +1664,6 @@ namespace boost {
 
     template <class K, class T, class H, class P, class A>
     unordered_map<K, T, H, P, A>::unordered_map()
-        : table_(boost::unordered::detail::default_bucket_count, hasher(),
-            key_equal(), allocator_type())
     {
     }
 
@@ -1730,7 +1690,7 @@ namespace boost {
             unordered_map::value_allocator_traits::
               select_on_container_copy_construction(other.get_allocator()))
     {
-      if (other.table_.size_) {
+      if (other.size()) {
         table_.copy_buckets(
           other.table_, boost::unordered::detail::true_type());
       }
@@ -1894,29 +1854,21 @@ namespace boost {
     typename unordered_map<K, T, H, P, A>::iterator
     unordered_map<K, T, H, P, A>::erase(iterator position)
     {
-      node_pointer node = table::get_node(position);
-      BOOST_ASSERT(node);
-      node_pointer next = table::next_node(node);
-      table_.erase_nodes_unique(node, next);
-      return iterator(next);
+      return table_.erase_node(position);
     }
 
     template <class K, class T, class H, class P, class A>
     typename unordered_map<K, T, H, P, A>::iterator
     unordered_map<K, T, H, P, A>::erase(const_iterator position)
     {
-      node_pointer node = table::get_node(position);
-      BOOST_ASSERT(node);
-      node_pointer next = table::next_node(node);
-      table_.erase_nodes_unique(node, next);
-      return iterator(next);
+      return table_.erase_node(position);
     }
 
     template <class K, class T, class H, class P, class A>
     typename unordered_map<K, T, H, P, A>::size_type
     unordered_map<K, T, H, P, A>::erase(const key_type& k)
     {
-      return table_.erase_key_unique_impl(this->key_eq(), k);
+      return table_.erase_key_unique_impl(k);
     }
 
     template <class K, class T, class H, class P, class A>
@@ -1924,11 +1876,7 @@ namespace boost {
     unordered_map<K, T, H, P, A>::erase(
       const_iterator first, const_iterator last)
     {
-      node_pointer last_node = table::get_node(last);
-      if (first == last)
-        return iterator(last_node);
-      table_.erase_nodes_unique(table::get_node(first), last_node);
-      return iterator(last_node);
+      return table_.erase_nodes_range(first, last);
     }
 
     template <class K, class T, class H, class P, class A>
@@ -1998,14 +1946,14 @@ namespace boost {
     typename unordered_map<K, T, H, P, A>::iterator
     unordered_map<K, T, H, P, A>::find(const key_type& k)
     {
-      return iterator(table_.find_node(k));
+      return iterator(table_.find(k));
     }
 
     template <class K, class T, class H, class P, class A>
     typename unordered_map<K, T, H, P, A>::const_iterator
     unordered_map<K, T, H, P, A>::find(const key_type& k) const
     {
-      return const_iterator(table_.find_node(k));
+      return const_iterator(table_.find(k));
     }
 
     template <class K, class T, class H, class P, class A>
@@ -2015,8 +1963,7 @@ namespace boost {
     unordered_map<K, T, H, P, A>::find(CompatibleKey const& k,
       CompatibleHash const& hash, CompatiblePredicate const& eq)
     {
-      return iterator(
-        table_.find_node_impl(table::policy::apply_hash(hash, k), k, eq));
+      return table_.transparent_find(k, hash, eq);
     }
 
     template <class K, class T, class H, class P, class A>
@@ -2026,8 +1973,7 @@ namespace boost {
     unordered_map<K, T, H, P, A>::find(CompatibleKey const& k,
       CompatibleHash const& hash, CompatiblePredicate const& eq) const
     {
-      return const_iterator(
-        table_.find_node_impl(table::policy::apply_hash(hash, k), k, eq));
+      return table_.transparent_find(k, hash, eq);
     }
 
     template <class K, class T, class H, class P, class A>
@@ -2042,8 +1988,12 @@ namespace boost {
       typename unordered_map<K, T, H, P, A>::iterator>
     unordered_map<K, T, H, P, A>::equal_range(const key_type& k)
     {
-      node_pointer n = table_.find_node(k);
-      return std::make_pair(iterator(n), iterator(n ? table::next_node(n) : n));
+      iterator first = table_.find(k);
+      iterator second = first;
+      if (second != this->end()) {
+        ++second;
+      }
+      return std::make_pair(first, second);
     }
 
     template <class K, class T, class H, class P, class A>
@@ -2051,9 +2001,12 @@ namespace boost {
       typename unordered_map<K, T, H, P, A>::const_iterator>
     unordered_map<K, T, H, P, A>::equal_range(const key_type& k) const
     {
-      node_pointer n = table_.find_node(k);
-      return std::make_pair(
-        const_iterator(n), const_iterator(n ? table::next_node(n) : n));
+      iterator first = table_.find(k);
+      iterator second = first;
+      if (second != this->end()) {
+        ++second;
+      }
+      return std::make_pair(const_iterator(first), const_iterator(second));
     }
 
     template <class K, class T, class H, class P, class A>
@@ -2074,10 +2027,12 @@ namespace boost {
     typename unordered_map<K, T, H, P, A>::mapped_type&
     unordered_map<K, T, H, P, A>::at(const key_type& k)
     {
+      typedef typename table::node_pointer node_pointer;
+
       if (table_.size_) {
-        node_pointer n = table_.find_node(k);
-        if (n)
-          return n->value().second;
+        node_pointer p = table_.find_node(k);
+        if (p)
+          return p->value().second;
       }
 
       boost::throw_exception(
@@ -2088,10 +2043,12 @@ namespace boost {
     typename unordered_map<K, T, H, P, A>::mapped_type const&
     unordered_map<K, T, H, P, A>::at(const key_type& k) const
     {
+      typedef typename table::node_pointer node_pointer;
+
       if (table_.size_) {
-        node_pointer n = table_.find_node(k);
-        if (n)
-          return n->value().second;
+        node_pointer p = table_.find_node(k);
+        if (p)
+          return p->value().second;
       }
 
       boost::throw_exception(
@@ -2110,9 +2067,13 @@ namespace boost {
     template <class K, class T, class H, class P, class A>
     float unordered_map<K, T, H, P, A>::load_factor() const BOOST_NOEXCEPT
     {
-      BOOST_ASSERT(table_.bucket_count_ != 0);
+      if (table_.size_ == 0) {
+        return 0.0f;
+      }
+
+      BOOST_ASSERT(table_.bucket_count() != 0);
       return static_cast<float>(table_.size_) /
-             static_cast<float>(table_.bucket_count_);
+             static_cast<float>(table_.bucket_count());
     }
 
     template <class K, class T, class H, class P, class A>
@@ -2130,8 +2091,7 @@ namespace boost {
     template <class K, class T, class H, class P, class A>
     void unordered_map<K, T, H, P, A>::reserve(size_type n)
     {
-      table_.rehash(static_cast<std::size_t>(
-        std::ceil(static_cast<double>(n) / table_.mlf_)));
+      table_.reserve(n);
     }
 
     template <class K, class T, class H, class P, class A>
@@ -2185,8 +2145,6 @@ namespace boost {
 
     template <class K, class T, class H, class P, class A>
     unordered_multimap<K, T, H, P, A>::unordered_multimap()
-        : table_(boost::unordered::detail::default_bucket_count, hasher(),
-            key_equal(), allocator_type())
     {
     }
 
@@ -2377,22 +2335,16 @@ namespace boost {
     typename unordered_multimap<K, T, H, P, A>::iterator
     unordered_multimap<K, T, H, P, A>::erase(iterator position)
     {
-      node_pointer node = table::get_node(position);
-      BOOST_ASSERT(node);
-      node_pointer next = table::next_node(node);
-      table_.erase_nodes_equiv(node, next);
-      return iterator(next);
+      BOOST_ASSERT(position != this->end());
+      return table_.erase_node(position);
     }
 
     template <class K, class T, class H, class P, class A>
     typename unordered_multimap<K, T, H, P, A>::iterator
     unordered_multimap<K, T, H, P, A>::erase(const_iterator position)
     {
-      node_pointer node = table::get_node(position);
-      BOOST_ASSERT(node);
-      node_pointer next = table::next_node(node);
-      table_.erase_nodes_equiv(node, next);
-      return iterator(next);
+      BOOST_ASSERT(position != this->end());
+      return table_.erase_node(position);
     }
 
     template <class K, class T, class H, class P, class A>
@@ -2407,11 +2359,7 @@ namespace boost {
     unordered_multimap<K, T, H, P, A>::erase(
       const_iterator first, const_iterator last)
     {
-      node_pointer last_node = table::get_node(last);
-      if (first == last)
-        return iterator(last_node);
-      table_.erase_nodes_equiv(table::get_node(first), last_node);
-      return iterator(last_node);
+      return table_.erase_nodes_range(first, last);
     }
 
     template <class K, class T, class H, class P, class A>
@@ -2489,14 +2437,14 @@ namespace boost {
     typename unordered_multimap<K, T, H, P, A>::iterator
     unordered_multimap<K, T, H, P, A>::find(const key_type& k)
     {
-      return iterator(table_.find_node(k));
+      return iterator(table_.find(k));
     }
 
     template <class K, class T, class H, class P, class A>
     typename unordered_multimap<K, T, H, P, A>::const_iterator
     unordered_multimap<K, T, H, P, A>::find(const key_type& k) const
     {
-      return const_iterator(table_.find_node(k));
+      return const_iterator(table_.find(k));
     }
 
     template <class K, class T, class H, class P, class A>
@@ -2506,8 +2454,7 @@ namespace boost {
     unordered_multimap<K, T, H, P, A>::find(CompatibleKey const& k,
       CompatibleHash const& hash, CompatiblePredicate const& eq)
     {
-      return iterator(
-        table_.find_node_impl(table::policy::apply_hash(hash, k), k, eq));
+      return table_.transparent_find(k, hash, eq);
     }
 
     template <class K, class T, class H, class P, class A>
@@ -2525,8 +2472,7 @@ namespace boost {
     typename unordered_multimap<K, T, H, P, A>::size_type
     unordered_multimap<K, T, H, P, A>::count(const key_type& k) const
     {
-      node_pointer n = table_.find_node(k);
-      return n ? table_.group_count(n) : 0;
+      return table_.group_count(k);
     }
 
     template <class K, class T, class H, class P, class A>
@@ -2534,9 +2480,8 @@ namespace boost {
       typename unordered_multimap<K, T, H, P, A>::iterator>
     unordered_multimap<K, T, H, P, A>::equal_range(const key_type& k)
     {
-      node_pointer n = table_.find_node(k);
-      return std::make_pair(
-        iterator(n), iterator(n ? table_.next_group(n) : n));
+      iterator n = table_.find(k);
+      return std::make_pair(n, (n == end() ? n : table_.next_group(k, n)));
     }
 
     template <class K, class T, class H, class P, class A>
@@ -2544,9 +2489,9 @@ namespace boost {
       typename unordered_multimap<K, T, H, P, A>::const_iterator>
     unordered_multimap<K, T, H, P, A>::equal_range(const key_type& k) const
     {
-      node_pointer n = table_.find_node(k);
-      return std::make_pair(
-        const_iterator(n), const_iterator(n ? table_.next_group(n) : n));
+      iterator n = table_.find(k);
+      return std::make_pair(const_iterator(n),
+        const_iterator(n == end() ? n : table_.next_group(k, n)));
     }
 
     template <class K, class T, class H, class P, class A>
@@ -2561,9 +2506,13 @@ namespace boost {
     template <class K, class T, class H, class P, class A>
     float unordered_multimap<K, T, H, P, A>::load_factor() const BOOST_NOEXCEPT
     {
-      BOOST_ASSERT(table_.bucket_count_ != 0);
+      if (table_.size_ == 0) {
+        return 0.0f;
+      }
+
+      BOOST_ASSERT(table_.bucket_count() != 0);
       return static_cast<float>(table_.size_) /
-             static_cast<float>(table_.bucket_count_);
+             static_cast<float>(table_.bucket_count());
     }
 
     template <class K, class T, class H, class P, class A>
@@ -2582,8 +2531,7 @@ namespace boost {
     template <class K, class T, class H, class P, class A>
     void unordered_multimap<K, T, H, P, A>::reserve(size_type n)
     {
-      table_.rehash(static_cast<std::size_t>(
-        std::ceil(static_cast<double>(n) / table_.mlf_)));
+      table_.reserve(n);
     }
 
     template <class K, class T, class H, class P, class A>
@@ -2643,16 +2591,14 @@ namespace boost {
       template <class K2, class T2, class H2, class P2, class A2>
       friend class boost::unordered::unordered_multimap;
 
-      typedef typename boost::unordered::detail::rebind_wrap<A,
-        std::pair<K const, T> >::type value_allocator;
-      typedef boost::unordered::detail::allocator_traits<value_allocator>
-        value_allocator_traits;
+      typedef typename boost::allocator_rebind<A, std::pair<K const, T> >::type
+        value_allocator;
+
       typedef N node;
-      typedef typename boost::unordered::detail::rebind_wrap<A, node>::type
-        node_allocator;
-      typedef boost::unordered::detail::allocator_traits<node_allocator>
-        node_allocator_traits;
-      typedef typename node_allocator_traits::pointer node_pointer;
+      typedef typename boost::allocator_rebind<A, node>::type node_allocator;
+
+      typedef
+        typename boost::allocator_pointer<node_allocator>::type node_pointer;
 
     public:
       typedef K key_type;
@@ -2681,8 +2627,8 @@ namespace boost {
       }
 
       node_handle_map(BOOST_RV_REF(node_handle_map) n) BOOST_NOEXCEPT
-        : ptr_(n.ptr_),
-          alloc_(boost::move(n.alloc_))
+          : ptr_(n.ptr_),
+            alloc_(boost::move(n.alloc_))
       {
         n.ptr_ = node_pointer();
       }
@@ -2690,8 +2636,8 @@ namespace boost {
       node_handle_map& operator=(BOOST_RV_REF(node_handle_map) n)
       {
         BOOST_ASSERT(!alloc_.has_value() ||
-                     value_allocator_traits::
-                       propagate_on_container_move_assignment::value ||
+                     boost::allocator_propagate_on_container_move_assignment<
+                       value_allocator>::type::value ||
                      (n.alloc_.has_value() && alloc_ == n.alloc_));
 
         if (ptr_) {
@@ -2702,8 +2648,8 @@ namespace boost {
         }
 
         if (!alloc_.has_value() ||
-            value_allocator_traits::propagate_on_container_move_assignment::
-              value) {
+            boost::allocator_propagate_on_container_move_assignment<
+              value_allocator>::type::value) {
           alloc_ = boost::move(n.alloc_);
         }
         ptr_ = n.ptr_;
@@ -2731,14 +2677,17 @@ namespace boost {
       }
 
       void swap(node_handle_map& n) BOOST_NOEXCEPT_IF(
-        value_allocator_traits::propagate_on_container_swap::value ||
-        value_allocator_traits::is_always_equal::value)
+        boost::allocator_propagate_on_container_swap<
+          value_allocator>::type::value ||
+        boost::allocator_is_always_equal<value_allocator>::type::value)
       {
-        BOOST_ASSERT(
-          !alloc_.has_value() || !n.alloc_.has_value() ||
-          value_allocator_traits::propagate_on_container_swap::value ||
-          alloc_ == n.alloc_);
-        if (value_allocator_traits::propagate_on_container_swap::value ||
+
+        BOOST_ASSERT(!alloc_.has_value() || !n.alloc_.has_value() ||
+                     boost::allocator_propagate_on_container_swap<
+                       value_allocator>::type::value ||
+                     alloc_ == n.alloc_);
+        if (boost::allocator_propagate_on_container_swap<
+              value_allocator>::type::value ||
             !alloc_.has_value() || !n.alloc_.has_value()) {
           boost::swap(alloc_, n.alloc_);
         }
@@ -2753,25 +2702,25 @@ namespace boost {
       x.swap(y);
     }
 
-    template <class N, class K, class T, class A> struct insert_return_type_map
+    template <class Iter, class NodeType> struct insert_return_type_map
     {
     private:
       BOOST_MOVABLE_BUT_NOT_COPYABLE(insert_return_type_map)
 
-      typedef typename boost::unordered::detail::rebind_wrap<A,
-        std::pair<K const, T> >::type value_allocator;
-      typedef N node_;
+      // typedef typename boost::allocator_rebind<A,
+      //   std::pair<K const, T> >::type value_allocator;
+      // typedef N node_;
 
     public:
+      Iter position;
       bool inserted;
-      boost::unordered::iterator_detail::iterator<node_> position;
-      boost::unordered::node_handle_map<N, K, T, A> node;
+      NodeType node;
 
-      insert_return_type_map() : inserted(false), position(), node() {}
+      insert_return_type_map() : position(), inserted(false), node() {}
 
       insert_return_type_map(BOOST_RV_REF(insert_return_type_map)
-          x) BOOST_NOEXCEPT : inserted(x.inserted),
-                              position(x.position),
+          x) BOOST_NOEXCEPT : position(x.position),
+                              inserted(x.inserted),
                               node(boost::move(x.node))
       {
       }
@@ -2785,9 +2734,9 @@ namespace boost {
       }
     };
 
-    template <class N, class K, class T, class A>
-    void swap(insert_return_type_map<N, K, T, A>& x,
-      insert_return_type_map<N, K, T, A>& y)
+    template <class Iter, class NodeType>
+    void swap(insert_return_type_map<Iter, NodeType>& x,
+      insert_return_type_map<Iter, NodeType>& y)
     {
       boost::swap(x.node, y.node);
       boost::swap(x.inserted, y.inserted);

include/boost/unordered/unordered_map_fwd.hpp

@@ -1,5 +1,6 @@
 
 // Copyright (C) 2008-2011 Daniel James.
+// Copyright (C) 2022 Christian Mazakas
 // Distributed under the Boost Software License, Version 1.0. (See accompanying
 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
 
@@ -59,7 +60,7 @@ namespace boost {
       unordered_multimap<K, T, H, P, A>& c, Predicate pred);
 
     template <class N, class K, class T, class A> class node_handle_map;
-    template <class N, class K, class T, class A> struct insert_return_type_map;
+    template <class Iter, class NodeType> struct insert_return_type_map;
   }
 
   using boost::unordered::unordered_map;

include/boost/unordered/unordered_set.hpp

@@ -1,6 +1,7 @@
 
 // Copyright (C) 2003-2004 Jeremy B. Maitin-Shepard.
 // Copyright (C) 2005-2011 Daniel James.
+// Copyright (C) 2022 Christian Mazakas
 // Distributed under the Boost Software License, Version 1.0. (See accompanying
 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
 
@@ -55,8 +56,6 @@ namespace boost {
       typedef boost::unordered::detail::set<A, T, H, P> types;
       typedef typename types::value_allocator_traits value_allocator_traits;
       typedef typename types::table table;
-      typedef typename table::node_pointer node_pointer;
-      typedef typename table::link_pointer link_pointer;
 
     public:
       typedef typename value_allocator_traits::pointer pointer;
@@ -68,9 +67,9 @@ namespace boost {
       typedef std::size_t size_type;
       typedef std::ptrdiff_t difference_type;
 
-      typedef typename table::iterator iterator;
+      typedef typename table::c_iterator iterator;
       typedef typename table::c_iterator const_iterator;
-      typedef typename table::l_iterator local_iterator;
+      typedef typename table::cl_iterator local_iterator;
       typedef typename table::cl_iterator const_local_iterator;
       typedef typename types::node_type node_type;
       typedef typename types::insert_return_type insert_return_type;
@@ -411,7 +410,7 @@ namespace boost {
 
       node_type extract(const key_type& k)
       {
-        return node_type(table_.extract_by_key(k), table_.node_alloc());
+        return node_type(table_.extract_by_key_impl(k), table_.node_alloc());
       }
 
       template <class Key>
@@ -455,8 +454,7 @@ namespace boost {
         size_type>::type
       erase(BOOST_FWD_REF(Key) k)
       {
-        return table_.erase_key_unique_impl(
-          this->key_eq(), boost::forward<Key>(k));
+        return table_.erase_key_unique_impl(boost::forward<Key>(k));
       }
 
       BOOST_UNORDERED_DEPRECATED("Use erase instead")
@@ -500,9 +498,7 @@ namespace boost {
         const_iterator>::type
       find(const Key& k) const
       {
-        return const_iterator(table_.find_node_impl(
-          table::policy::apply_hash(this->hash_function(), k), k,
-          this->key_eq()));
+        return const_iterator(table_.find(k));
       }
 
       template <class CompatibleKey, class CompatibleHash,
@@ -512,9 +508,7 @@ namespace boost {
 
       bool contains(key_type const& k) const
       {
-        return 0 != table_.find_node_impl(
-                      table::policy::apply_hash(this->hash_function(), k), k,
-                      this->key_eq());
+        return table_.find(k) != this->end();
       }
 
       template <class Key>
@@ -522,9 +516,7 @@ namespace boost {
         bool>::type
       contains(const Key& k) const
       {
-        return 0 != table_.find_node_impl(
-                      table::policy::apply_hash(this->hash_function(), k), k,
-                      this->key_eq());
+        return table_.find(k) != this->end();
       }
 
       size_type count(const key_type&) const;
@@ -534,11 +526,7 @@ namespace boost {
         size_type>::type
       count(const Key& k) const
       {
-        node_pointer n = table_.find_node_impl(
-          table::policy::apply_hash(this->hash_function(), k), k,
-          this->key_eq());
-
-        return n ? 1 : 0;
+        return table_.find(k) != this->end() ? 1 : 0;
       }
 
       std::pair<const_iterator, const_iterator> equal_range(
@@ -549,19 +537,20 @@ namespace boost {
         std::pair<const_iterator, const_iterator> >::type
       equal_range(Key const& k) const
       {
-        node_pointer n = table_.find_node_impl(
-          table::policy::apply_hash(this->hash_function(), k), k,
-          this->key_eq());
+        iterator n = table_.find(k);
+        iterator m = n;
+        if (m != this->end()) {
+          ++m;
+        }
 
-        return std::make_pair(
-          const_iterator(n), const_iterator(n ? table::next_node(n) : n));
+        return std::make_pair(const_iterator(n), const_iterator(m));
       }
 
       // bucket interface
 
       size_type bucket_count() const BOOST_NOEXCEPT
       {
-        return table_.bucket_count_;
+        return table_.bucket_count();
       }
 
       size_type max_bucket_count() const BOOST_NOEXCEPT
@@ -578,12 +567,12 @@ namespace boost {
 
       local_iterator begin(size_type n)
       {
-        return local_iterator(table_.begin(n), n, table_.bucket_count_);
+        return local_iterator(table_.begin(n));
       }
 
       const_local_iterator begin(size_type n) const
       {
-        return const_local_iterator(table_.begin(n), n, table_.bucket_count_);
+        return const_local_iterator(table_.begin(n));
       }
 
       local_iterator end(size_type) { return local_iterator(); }
@@ -595,7 +584,7 @@ namespace boost {
 
       const_local_iterator cbegin(size_type n) const
       {
-        return const_local_iterator(table_.begin(n), n, table_.bucket_count_);
+        return const_local_iterator(table_.begin(n));
       }
 
       const_local_iterator cend(size_type) const
@@ -684,8 +673,6 @@ namespace boost {
       typedef boost::unordered::detail::set<A, T, H, P> types;
       typedef typename types::value_allocator_traits value_allocator_traits;
       typedef typename types::table table;
-      typedef typename table::node_pointer node_pointer;
-      typedef typename table::link_pointer link_pointer;
 
     public:
       typedef typename value_allocator_traits::pointer pointer;
@@ -697,9 +684,9 @@ namespace boost {
       typedef std::size_t size_type;
       typedef std::ptrdiff_t difference_type;
 
-      typedef typename table::iterator iterator;
+      typedef typename table::c_iterator iterator;
       typedef typename table::c_iterator const_iterator;
-      typedef typename table::l_iterator local_iterator;
+      typedef typename table::cl_iterator local_iterator;
       typedef typename table::cl_iterator const_local_iterator;
       typedef typename types::node_type node_type;
 
@@ -1035,7 +1022,7 @@ namespace boost {
 
       node_type extract(const key_type& k)
       {
-        return node_type(table_.extract_by_key(k), table_.node_alloc());
+        return node_type(table_.extract_by_key_impl(k), table_.node_alloc());
       }
 
       template <class Key>
@@ -1076,7 +1063,7 @@ namespace boost {
         size_type>::type
       erase(const Key& k)
       {
-        return table_.erase_key_equiv_impl(this->key_eq(), k);
+        return table_.erase_key_equiv_impl(k);
       }
 
       iterator erase(const_iterator, const_iterator);
@@ -1121,9 +1108,7 @@ namespace boost {
         const_iterator>::type
       find(const Key& k) const
       {
-        return const_iterator(table_.find_node_impl(
-          table::policy::apply_hash(this->hash_function(), k), k,
-          this->key_eq()));
+        return table_.find(k);
       }
 
       template <class CompatibleKey, class CompatibleHash,
@@ -1133,9 +1118,7 @@ namespace boost {
 
       bool contains(const key_type& k) const
       {
-        return 0 != table_.find_node_impl(
-                      table::policy::apply_hash(this->hash_function(), k), k,
-                      this->key_eq());
+        return table_.find(k) != this->end();
       }
 
       template <class Key>
@@ -1143,9 +1126,7 @@ namespace boost {
         bool>::type
       contains(const Key& k) const
       {
-        return 0 != table_.find_node_impl(
-                      table::policy::apply_hash(this->hash_function(), k), k,
-                      this->key_eq());
+        return table_.find(k) != this->end();
       }
 
       size_type count(const key_type&) const;
@@ -1155,11 +1136,7 @@ namespace boost {
         size_type>::type
       count(const Key& k) const
       {
-        node_pointer n = table_.find_node_impl(
-          table::policy::apply_hash(this->hash_function(), k), k,
-          this->key_eq());
-
-        return n ? table_.group_count(n) : 0;
+        return table_.group_count(k);
       }
 
       std::pair<const_iterator, const_iterator> equal_range(
@@ -1170,19 +1147,16 @@ namespace boost {
         std::pair<const_iterator, const_iterator> >::type
       equal_range(const Key& k) const
       {
-        node_pointer n = table_.find_node_impl(
-          table::policy::apply_hash(this->hash_function(), k), k,
-          this->key_eq());
-
-        return std::make_pair(
-          const_iterator(n), const_iterator(n ? table_.next_group(n) : n));
+        iterator first = table_.find(k);
+        iterator last = table_.next_group(k, first);
+        return std::make_pair(const_iterator(first), const_iterator(last));
       }
 
       // bucket interface
 
       size_type bucket_count() const BOOST_NOEXCEPT
       {
-        return table_.bucket_count_;
+        return table_.bucket_count();
       }
 
       size_type max_bucket_count() const BOOST_NOEXCEPT
@@ -1199,12 +1173,12 @@ namespace boost {
 
       local_iterator begin(size_type n)
       {
-        return local_iterator(table_.begin(n), n, table_.bucket_count_);
+        return local_iterator(table_.begin(n));
       }
 
       const_local_iterator begin(size_type n) const
       {
-        return const_local_iterator(table_.begin(n), n, table_.bucket_count_);
+        return const_local_iterator(table_.begin(n));
       }
 
       local_iterator end(size_type) { return local_iterator(); }
@@ -1216,7 +1190,7 @@ namespace boost {
 
       const_local_iterator cbegin(size_type n) const
       {
-        return const_local_iterator(table_.begin(n), n, table_.bucket_count_);
+        return const_local_iterator(table_.begin(n));
       }
 
       const_local_iterator cend(size_type) const
@@ -1292,8 +1266,6 @@ namespace boost {
     ////////////////////////////////////////////////////////////////////////////
     template <class T, class H, class P, class A>
     unordered_set<T, H, P, A>::unordered_set()
-        : table_(boost::unordered::detail::default_bucket_count, hasher(),
-            key_equal(), allocator_type())
     {
     }
 
@@ -1319,7 +1291,7 @@ namespace boost {
             unordered_set::value_allocator_traits::
               select_on_container_copy_construction(other.get_allocator()))
     {
-      if (other.table_.size_) {
+      if (other.size()) {
         table_.copy_buckets(
           other.table_, boost::unordered::detail::true_type());
       }
@@ -1483,29 +1455,21 @@ namespace boost {
     typename unordered_set<T, H, P, A>::iterator
     unordered_set<T, H, P, A>::erase(const_iterator position)
     {
-      node_pointer node = table::get_node(position);
-      BOOST_ASSERT(node);
-      node_pointer next = table::next_node(node);
-      table_.erase_nodes_unique(node, next);
-      return iterator(next);
+      return table_.erase_node(position);
     }
 
     template <class T, class H, class P, class A>
     typename unordered_set<T, H, P, A>::size_type
     unordered_set<T, H, P, A>::erase(const key_type& k)
     {
-      return table_.erase_key_unique_impl(this->key_eq(), k);
+      return table_.erase_key_unique_impl(k);
     }
 
     template <class T, class H, class P, class A>
     typename unordered_set<T, H, P, A>::iterator
     unordered_set<T, H, P, A>::erase(const_iterator first, const_iterator last)
     {
-      node_pointer last_node = table::get_node(last);
-      if (first == last)
-        return iterator(last_node);
-      table_.erase_nodes_unique(table::get_node(first), last_node);
-      return iterator(last_node);
+      return table_.erase_nodes_range(first, last);
     }
 
     template <class T, class H, class P, class A>
@@ -1575,7 +1539,7 @@ namespace boost {
     typename unordered_set<T, H, P, A>::const_iterator
     unordered_set<T, H, P, A>::find(const key_type& k) const
     {
-      return const_iterator(table_.find_node(k));
+      return const_iterator(table_.find(k));
     }
 
     template <class T, class H, class P, class A>
@@ -1585,8 +1549,7 @@ namespace boost {
     unordered_set<T, H, P, A>::find(CompatibleKey const& k,
       CompatibleHash const& hash, CompatiblePredicate const& eq) const
     {
-      return const_iterator(
-        table_.find_node_impl(table::policy::apply_hash(hash, k), k, eq));
+      return table_.transparent_find(k, hash, eq);
     }
 
     template <class T, class H, class P, class A>
@@ -1601,9 +1564,12 @@ namespace boost {
       typename unordered_set<T, H, P, A>::const_iterator>
     unordered_set<T, H, P, A>::equal_range(const key_type& k) const
     {
-      node_pointer n = table_.find_node(k);
-      return std::make_pair(
-        const_iterator(n), const_iterator(n ? table::next_node(n) : n));
+      iterator first = table_.find(k);
+      iterator second = first;
+      if (second != this->end()) {
+        ++second;
+      }
+      return std::make_pair(first, second);
     }
 
     template <class T, class H, class P, class A>
@@ -1618,9 +1584,13 @@ namespace boost {
     template <class T, class H, class P, class A>
     float unordered_set<T, H, P, A>::load_factor() const BOOST_NOEXCEPT
     {
-      BOOST_ASSERT(table_.bucket_count_ != 0);
+      if (table_.size_ == 0) {
+        return 0.0f;
+      }
+
+      BOOST_ASSERT(table_.bucket_count() != 0);
       return static_cast<float>(table_.size_) /
-             static_cast<float>(table_.bucket_count_);
+             static_cast<float>(table_.bucket_count());
     }
 
     template <class T, class H, class P, class A>
@@ -1638,8 +1608,7 @@ namespace boost {
     template <class T, class H, class P, class A>
     void unordered_set<T, H, P, A>::reserve(size_type n)
     {
-      table_.rehash(static_cast<std::size_t>(
-        std::ceil(static_cast<double>(n) / table_.mlf_)));
+      table_.reserve(n);
     }
 
     template <class T, class H, class P, class A>
@@ -1693,8 +1662,6 @@ namespace boost {
 
     template <class T, class H, class P, class A>
     unordered_multiset<T, H, P, A>::unordered_multiset()
-        : table_(boost::unordered::detail::default_bucket_count, hasher(),
-            key_equal(), allocator_type())
     {
     }
 
@@ -1883,11 +1850,8 @@ namespace boost {
     typename unordered_multiset<T, H, P, A>::iterator
     unordered_multiset<T, H, P, A>::erase(const_iterator position)
     {
-      node_pointer node = table::get_node(position);
-      BOOST_ASSERT(node);
-      node_pointer next = table::next_node(node);
-      table_.erase_nodes_equiv(node, next);
-      return iterator(next);
+      BOOST_ASSERT(position != this->end());
+      return table_.erase_node(position);
     }
 
     template <class T, class H, class P, class A>
@@ -1902,11 +1866,7 @@ namespace boost {
     unordered_multiset<T, H, P, A>::erase(
       const_iterator first, const_iterator last)
     {
-      node_pointer last_node = table::get_node(last);
-      if (first == last)
-        return iterator(last_node);
-      table_.erase_nodes_equiv(table::get_node(first), last_node);
-      return iterator(last_node);
+      return table_.erase_nodes_range(first, last);
     }
 
     template <class T, class H, class P, class A>
@@ -1984,7 +1944,7 @@ namespace boost {
     typename unordered_multiset<T, H, P, A>::const_iterator
     unordered_multiset<T, H, P, A>::find(const key_type& k) const
     {
-      return const_iterator(table_.find_node(k));
+      return const_iterator(table_.find(k));
     }
 
     template <class T, class H, class P, class A>
@@ -1994,16 +1954,14 @@ namespace boost {
     unordered_multiset<T, H, P, A>::find(CompatibleKey const& k,
       CompatibleHash const& hash, CompatiblePredicate const& eq) const
     {
-      return const_iterator(
-        table_.find_node_impl(table::policy::apply_hash(hash, k), k, eq));
+      return table_.transparent_find(k, hash, eq);
     }
 
     template <class T, class H, class P, class A>
     typename unordered_multiset<T, H, P, A>::size_type
     unordered_multiset<T, H, P, A>::count(const key_type& k) const
     {
-      node_pointer n = table_.find_node(k);
-      return n ? table_.group_count(n) : 0;
+      return table_.group_count(k);
     }
 
     template <class T, class H, class P, class A>
@@ -2011,9 +1969,9 @@ namespace boost {
       typename unordered_multiset<T, H, P, A>::const_iterator>
     unordered_multiset<T, H, P, A>::equal_range(const key_type& k) const
     {
-      node_pointer n = table_.find_node(k);
-      return std::make_pair(
-        const_iterator(n), const_iterator(n ? table_.next_group(n) : n));
+      iterator n = table_.find(k);
+      return std::make_pair(const_iterator(n),
+        const_iterator(n == end() ? n : table_.next_group(k, n)));
     }
 
     template <class T, class H, class P, class A>
@@ -2028,9 +1986,13 @@ namespace boost {
     template <class T, class H, class P, class A>
     float unordered_multiset<T, H, P, A>::load_factor() const BOOST_NOEXCEPT
     {
-      BOOST_ASSERT(table_.bucket_count_ != 0);
+      if (table_.size_ == 0) {
+        return 0.0f;
+      }
+
+      BOOST_ASSERT(table_.bucket_count() != 0);
       return static_cast<float>(table_.size_) /
-             static_cast<float>(table_.bucket_count_);
+             static_cast<float>(table_.bucket_count());
     }
 
     template <class T, class H, class P, class A>
@@ -2048,8 +2010,7 @@ namespace boost {
     template <class T, class H, class P, class A>
     void unordered_multiset<T, H, P, A>::reserve(size_type n)
     {
-      table_.rehash(static_cast<std::size_t>(
-        std::ceil(static_cast<double>(n) / table_.mlf_)));
+      table_.reserve(n);
     }
 
     template <class T, class H, class P, class A>
@@ -2217,25 +2178,25 @@ namespace boost {
       x.swap(y);
     }
 
-    template <typename N, typename T, typename A> struct insert_return_type_set
+    template <class Iter, class NodeType> struct insert_return_type_set
     {
     private:
       BOOST_MOVABLE_BUT_NOT_COPYABLE(insert_return_type_set)
 
-      typedef typename boost::unordered::detail::rebind_wrap<A, T>::type
-        value_allocator;
-      typedef N node_;
+      // typedef typename boost::unordered::detail::rebind_wrap<A, T>::type
+      //   value_allocator;
+      // typedef N node_;
 
     public:
+      Iter position;
       bool inserted;
-      boost::unordered::iterator_detail::c_iterator<node_> position;
-      boost::unordered::node_handle_set<N, T, A> node;
+      NodeType node;
 
-      insert_return_type_set() : inserted(false), position(), node() {}
+      insert_return_type_set() : position(), inserted(false), node() {}
 
       insert_return_type_set(BOOST_RV_REF(insert_return_type_set)
-          x) BOOST_NOEXCEPT : inserted(x.inserted),
-                              position(x.position),
+          x) BOOST_NOEXCEPT : position(x.position),
+                              inserted(x.inserted),
                               node(boost::move(x.node))
       {
       }
@@ -2249,9 +2210,9 @@ namespace boost {
       }
     };
 
-    template <typename N, typename T, typename A>
+    template <class Iter, class NodeType>
     void swap(
-      insert_return_type_set<N, T, A>& x, insert_return_type_set<N, T, A>& y)
+      insert_return_type_set<Iter, NodeType>& x, insert_return_type_set<Iter, NodeType>& y)
     {
       boost::swap(x.node, y.node);
       boost::swap(x.inserted, y.inserted);

include/boost/unordered/unordered_set_fwd.hpp

@@ -1,5 +1,6 @@
 
 // Copyright (C) 2008-2011 Daniel James.
+// Copyright (C) 2022 Christian Mazakas
 // Distributed under the Boost Software License, Version 1.0. (See accompanying
 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
 
@@ -57,7 +58,7 @@ namespace boost {
       unordered_multiset<K, H, P, A>& c, Predicate pred);
 
     template <class N, class T, class A> class node_handle_set;
-    template <class N, class T, class A> struct insert_return_type_set;
+    template <class Iter, class NodeType> struct insert_return_type_set;
   }
 
   using boost::unordered::unordered_set;

test/CMakeLists.txt

@@ -0,0 +1,17 @@
+# Copyright 2018, 2019 Peter Dimov
+# Distributed under the Boost Software License, Version 1.0.
+# See accompanying file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt
+
+include(BoostTestJamfile OPTIONAL RESULT_VARIABLE HAVE_BOOST_TEST)
+
+if(HAVE_BOOST_TEST)
+
+boost_test_jamfile(
+  FILE Jamfile.v2 
+  LINK_LIBRARIES 
+    Boost::unordered 
+    Boost::core
+    Boost::concept_check
+)
+
+endif()

test/Jamfile.v2

@@ -1,5 +1,6 @@
 
 # Copyright 2006-2008 Daniel James.
+# Copyright 2022 Christian Mazakas
 # Distributed under the Boost Software License, Version 1.0. (See accompanying
 # file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
 
@@ -23,88 +24,127 @@ project
         <toolset>clang:<cxxflags>$(clang-flags)
         <toolset>msvc:<cxxflags>$(msvc-flags)
 
+        <toolset>gcc-4.4:<cxxflags>-Wno-strict-aliasing
+        <toolset>gcc-4.4:<cxxflags>-fno-deduce-init-list
+
         <toolset>gcc:<warnings-as-errors>on
         <toolset>clang:<warnings-as-errors>on
         <toolset>msvc:<warnings-as-errors>on
     ;
 
-#alias framework : /boost/test//boost_unit_test_framework ;
-alias framework : ;
+run unordered/prime_fmod_tests.cpp ;
+run unordered/fwd_set_test.cpp ;
+run unordered/fwd_map_test.cpp ;
+run unordered/allocator_traits.cpp ;
+run unordered/minimal_allocator.cpp ;
+run unordered/compile_set.cpp ;
+run unordered/compile_map.cpp ;
+run unordered/noexcept_tests.cpp ;
+run unordered/link_test_1.cpp unordered/link_test_2.cpp ;
+run unordered/incomplete_test.cpp ;
+run unordered/simple_tests.cpp ;
+run unordered/equivalent_keys_tests.cpp ;
+run unordered/constructor_tests.cpp ;
+run unordered/copy_tests.cpp ;
+run unordered/move_tests.cpp ;
+run unordered/post_move_tests.cpp ;
+run unordered/assign_tests.cpp ;
+run unordered/insert_tests.cpp ;
+run unordered/insert_stable_tests.cpp ;
+run unordered/insert_hint_tests.cpp ;
+run unordered/emplace_tests.cpp ;
+run unordered/unnecessary_copy_tests.cpp ;
+run unordered/erase_tests.cpp : : : <define>BOOST_UNORDERED_SUPPRESS_DEPRECATED ;
+run unordered/erase_equiv_tests.cpp ;
+run unordered/extract_tests.cpp ;
+run unordered/node_handle_tests.cpp ;
+run unordered/merge_tests.cpp ;
+compile-fail unordered/insert_node_type_fail.cpp : <define>UNORDERED_TEST_MAP : insert_node_type_fail_map ;
+compile-fail unordered/insert_node_type_fail.cpp : <define>UNORDERED_TEST_MULTIMAP : insert_node_type_fail_multimap ;
+compile-fail unordered/insert_node_type_fail.cpp : <define>UNORDERED_TEST_SET : insert_node_type_fail_set ;
+compile-fail unordered/insert_node_type_fail.cpp : <define>UNORDERED_TEST_MULTISET : insert_node_type_fail_multiset ;
+run unordered/find_tests.cpp ;
+run unordered/at_tests.cpp ;
+run unordered/bucket_tests.cpp ;
+run unordered/load_factor_tests.cpp ;
+run unordered/rehash_tests.cpp ;
+run unordered/equality_tests.cpp ;
+run unordered/swap_tests.cpp ;
+run unordered/deduction_tests.cpp ;
+run unordered/scoped_allocator.cpp : : : <toolset>msvc-14.0:<build>no ;
+run unordered/transparent_tests.cpp ;
+run unordered/reserve_tests.cpp ;
+run unordered/contains_tests.cpp ;
+run unordered/erase_if.cpp ;
+run unordered/scary_tests.cpp ;
 
-test-suite unordered
-    :
-        [ run unordered/fwd_set_test.cpp ]
-        [ run unordered/fwd_map_test.cpp ]
-        [ run unordered/allocator_traits.cpp ]
-        [ run unordered/minimal_allocator.cpp ]
-        [ run unordered/compile_set.cpp ]
-        [ run unordered/compile_map.cpp ]
-        [ run unordered/noexcept_tests.cpp ]
-        [ run unordered/link_test_1.cpp unordered/link_test_2.cpp ]
-        [ run unordered/incomplete_test.cpp ]
-        [ run unordered/simple_tests.cpp ]
-        [ run unordered/equivalent_keys_tests.cpp ]
-        [ run unordered/constructor_tests.cpp ]
-        [ run unordered/copy_tests.cpp ]
-        [ run unordered/move_tests.cpp ]
-        [ run unordered/assign_tests.cpp ]
-        [ run unordered/insert_tests.cpp ]
-        [ run unordered/insert_stable_tests.cpp ]
-        [ run unordered/insert_hint_tests.cpp ]
-        [ run unordered/emplace_tests.cpp ]
-        [ run unordered/unnecessary_copy_tests.cpp ]
-        [ run unordered/erase_tests.cpp : : : <define>BOOST_UNORDERED_SUPPRESS_DEPRECATED ]
-        [ run unordered/erase_equiv_tests.cpp ]
-        [ run unordered/extract_tests.cpp ]
-        [ run unordered/node_handle_tests.cpp ]
-        [ run unordered/merge_tests.cpp ]
-        [ compile-fail unordered/insert_node_type_fail.cpp : <define>UNORDERED_TEST_MAP : insert_node_type_fail_map ]
-        [ compile-fail unordered/insert_node_type_fail.cpp : <define>UNORDERED_TEST_MULTIMAP : insert_node_type_fail_multimap ]
-        [ compile-fail unordered/insert_node_type_fail.cpp : <define>UNORDERED_TEST_SET : insert_node_type_fail_set ]
-        [ compile-fail unordered/insert_node_type_fail.cpp : <define>UNORDERED_TEST_MULTISET : insert_node_type_fail_multiset ]
-        [ run unordered/find_tests.cpp ]
-        [ run unordered/at_tests.cpp ]
-        [ run unordered/bucket_tests.cpp ]
-        [ run unordered/load_factor_tests.cpp ]
-        [ run unordered/rehash_tests.cpp ]
-        [ run unordered/equality_tests.cpp ]
-        [ run unordered/swap_tests.cpp ]
-        [ run unordered/detail_tests.cpp ]
-        [ run unordered/deduction_tests.cpp ]
-        [ run unordered/scoped_allocator.cpp : : : <toolset>msvc-14.0:<build>no ]
-        [ run unordered/transparent_tests.cpp ]
-        [ run unordered/reserve_tests.cpp ]
-        [ run unordered/contains_tests.cpp ]
-        [ run unordered/mix_policy.cpp ]
-        [ run unordered/erase_if.cpp ]
+run unordered/compile_set.cpp : : : <define>BOOST_UNORDERED_USE_MOVE : bmove_compile_set ;
+run unordered/compile_map.cpp : : : <define>BOOST_UNORDERED_USE_MOVE : bmove_compile_map ;
+run unordered/copy_tests.cpp : : : <define>BOOST_UNORDERED_USE_MOVE : bmove_copy ;
+run unordered/move_tests.cpp : : : <define>BOOST_UNORDERED_USE_MOVE : bmove_move ;
+run unordered/assign_tests.cpp : : : <define>BOOST_UNORDERED_USE_MOVE : bmove_assign ;
 
-        [ run unordered/compile_set.cpp : :
-            : <define>BOOST_UNORDERED_USE_MOVE
-            : bmove_compile_set ]
-        [ run unordered/compile_map.cpp : :
-            : <define>BOOST_UNORDERED_USE_MOVE
-            : bmove_compile_map ]
-        [ run unordered/copy_tests.cpp : :
-            : <define>BOOST_UNORDERED_USE_MOVE
-            : bmove_copy ]
-        [ run unordered/move_tests.cpp : :
-            : <define>BOOST_UNORDERED_USE_MOVE
-            : bmove_move ]
-        [ run unordered/assign_tests.cpp : :
-            : <define>BOOST_UNORDERED_USE_MOVE
-            : bmove_assign ]
-    ;
 
-test-suite unordered-exception
-    :
-        [ run exception/constructor_exception_tests.cpp framework ]
-        [ run exception/copy_exception_tests.cpp framework ]
-        [ run exception/assign_exception_tests.cpp framework ]
-        [ run exception/move_assign_exception_tests.cpp framework ]
-        [ run exception/insert_exception_tests.cpp framework ]
-        [ run exception/erase_exception_tests.cpp framework ]
-        [ run exception/rehash_exception_tests.cpp framework ]
-        [ run exception/swap_exception_tests.cpp framework : : :
-            <define>BOOST_UNORDERED_SWAP_METHOD=2 ]
-        [ run exception/merge_exception_tests.cpp framework ]
-    ;
+run exception/constructor_exception_tests.cpp ;
+run exception/copy_exception_tests.cpp ;
+run exception/assign_exception_tests.cpp ;
+run exception/move_assign_exception_tests.cpp ;
+run exception/insert_exception_tests.cpp ;
+run exception/erase_exception_tests.cpp ;
+run exception/rehash_exception_tests.cpp ;
+run exception/swap_exception_tests.cpp : : : <define>BOOST_UNORDERED_SWAP_METHOD=2 ;
+run exception/merge_exception_tests.cpp ;
+
+run quick.cpp ;
+
+import ../../config/checks/config : requires ;
+
+CPP11 = [ requires cxx11_constexpr cxx11_noexcept cxx11_decltype cxx11_alignas ] ;
+
+rule build_foa ( name )
+{
+  run unordered/$(name).cpp : : : $(CPP11) <define>BOOST_UNORDERED_FOA_TESTS : foa_$(name) ;
+}
+
+build_foa fwd_set_test ;
+build_foa fwd_map_test ;
+build_foa compile_set ;
+build_foa compile_map ;
+build_foa noexcept_tests ;
+run unordered/link_test_1.cpp unordered/link_test_2.cpp : : : $(CPP11) <define>BOOST_UNORDERED_FOA_TESTS : foa_link_test ;
+build_foa incomplete_test ;
+build_foa simple_tests ;
+build_foa equivalent_keys_tests ;
+build_foa constructor_tests ;
+build_foa copy_tests ;
+build_foa move_tests ;
+build_foa post_move_tests ;
+build_foa assign_tests ;
+build_foa insert_tests ;
+build_foa insert_hint_tests ;
+build_foa emplace_tests ;
+build_foa erase_tests ;
+build_foa merge_tests ;
+build_foa find_tests ;
+build_foa at_tests ;
+build_foa load_factor_tests ;
+build_foa rehash_tests ;
+build_foa equality_tests ;
+build_foa swap_tests ;
+run unordered/scoped_allocator.cpp : : : $(CPP11) <toolset>msvc-14.0:<build>no <define>BOOST_UNORDERED_FOA_TESTS : foa_scoped_allocator ;
+build_foa transparent_tests ;
+build_foa reserve_tests ;
+build_foa contains_tests ;
+build_foa erase_if ;
+build_foa scary_tests ;
+build_foa init_type_insert_tests ;
+
+run exception/constructor_exception_tests.cpp : : : $(CPP11) <define>BOOST_UNORDERED_FOA_TESTS : foa_constructor_exception_tests ;
+run exception/copy_exception_tests.cpp        : : : $(CPP11) <define>BOOST_UNORDERED_FOA_TESTS : foa_copy_exception_tests ;
+run exception/assign_exception_tests.cpp      : : : $(CPP11) <define>BOOST_UNORDERED_FOA_TESTS : foa_assign_exception_tests ;
+run exception/move_assign_exception_tests.cpp : : : $(CPP11) <define>BOOST_UNORDERED_FOA_TESTS : foa_move_assign_exception_tests ;
+run exception/insert_exception_tests.cpp      : : : $(CPP11) <define>BOOST_UNORDERED_FOA_TESTS : foa_insert_exception_tests ;
+run exception/erase_exception_tests.cpp       : : : $(CPP11) <define>BOOST_UNORDERED_FOA_TESTS : foa_erase_exception_tests ;
+run exception/rehash_exception_tests.cpp      : : : $(CPP11) <define>BOOST_UNORDERED_FOA_TESTS : foa_rehash_exception_tests ;
+run exception/swap_exception_tests.cpp        : : : $(CPP11) <define>BOOST_UNORDERED_FOA_TESTS : foa_swap_exception_tests ;
+run exception/merge_exception_tests.cpp       : : : $(CPP11) <define>BOOST_UNORDERED_FOA_TESTS : foa_merge_exception_tests ;

test/cmake_install_test/CMakeLists.txt

@@ -0,0 +1,17 @@
+# Copyright 2018, 2019, 2021 Peter Dimov
+# Distributed under the Boost Software License, Version 1.0.
+# See accompanying file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt
+
+cmake_minimum_required(VERSION 3.5...3.20)
+
+project(cmake_install_test LANGUAGES CXX)
+
+find_package(boost_unordered REQUIRED)
+
+add_executable(quick ../quick.cpp)
+target_link_libraries(quick Boost::unordered)
+
+enable_testing()
+add_test(quick quick)
+
+add_custom_target(check COMMAND ${CMAKE_CTEST_COMMAND} --output-on-failure -C $<CONFIG>)

test/cmake_subdir_test/CMakeLists.txt

@@ -0,0 +1,49 @@
+# Copyright 2018, 2019, 2021 Peter Dimov
+# Distributed under the Boost Software License, Version 1.0.
+# See accompanying file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt
+
+cmake_minimum_required(VERSION 3.5...3.20)
+
+project(cmake_subdir_test LANGUAGES CXX)
+
+add_subdirectory(../.. boostorg/unordered)
+
+# `boostdep --brief unordered`
+
+set(deps
+
+# Primary dependencies
+
+assert
+config
+container_hash
+core
+move
+mp11
+predef
+preprocessor
+throw_exception
+tuple
+type_traits
+
+# Secondary dependencies
+
+detail
+integer
+static_assert
+winapi
+)
+
+foreach(dep IN LISTS deps)
+
+  add_subdirectory(../../../${dep} boostorg/${dep})
+
+endforeach()
+
+add_executable(quick ../quick.cpp)
+target_link_libraries(quick Boost::unordered Boost::core)
+
+enable_testing()
+add_test(quick quick)
+
+add_custom_target(check COMMAND ${CMAKE_CTEST_COMMAND} --output-on-failure -C $<CONFIG>)

test/exception/containers.hpp

@@ -1,17 +1,33 @@
 
 // Copyright 2006-2009 Daniel James.
+// Copyright 2022 Christian Mazakas.
 // Distributed under the Boost Software License, Version 1.0. (See accompanying
 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
 
-// clang-format off
-#include "../helpers/prefix.hpp"
-#include <boost/unordered_map.hpp>
-#include <boost/unordered_set.hpp>
-#include "../helpers/postfix.hpp"
-// clang-format on
+#include "../helpers/unordered.hpp"
 
 #include "../objects/exception.hpp"
 
+#ifdef BOOST_UNORDERED_FOA_TESTS
+typedef boost::unordered_flat_set<test::exception::object,
+  test::exception::hash, test::exception::equal_to,
+  test::exception::allocator<test::exception::object> >
+  test_set;
+
+typedef boost::unordered_flat_map<test::exception::object,
+  test::exception::object, test::exception::hash, test::exception::equal_to,
+  test::exception::allocator2<test::exception::object> >
+  test_map;
+
+typedef boost::unordered_flat_set<
+  std::pair<test::exception::object, test::exception::object>,
+  test::exception::hash, test::exception::equal_to,
+  test::exception::allocator<test::exception::object> >
+  test_pair_set;
+
+#define CONTAINER_SEQ (test_set)(test_map)
+#define CONTAINER_PAIR_SEQ (test_pair_set)(test_map)
+#else
 typedef boost::unordered_set<test::exception::object, test::exception::hash,
   test::exception::equal_to,
   test::exception::allocator<test::exception::object> >
@@ -42,3 +58,5 @@ typedef boost::unordered_multiset<
 #define CONTAINER_SEQ (test_set)(test_multiset)(test_map)(test_multimap)
 #define CONTAINER_PAIR_SEQ                                                     \
   (test_pair_set)(test_pair_multiset)(test_map)(test_multimap)
+
+#endif

test/exception/insert_exception_tests.cpp

@@ -1,5 +1,6 @@
 
 // Copyright 2006-2009 Daniel James.
+// Copyright 2022 Christian Mazakas.
 // Distributed under the Boost Software License, Version 1.0. (See accompanying
 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
 #include "./containers.hpp"
@@ -95,7 +96,7 @@ void insert_rehash_exception_test(
   T*, Inserter insert, test::random_generator gen)
 {
   for (int i = 0; i < 5; ++i) {
-    T x;
+    T x(1);
     rehash_prep(x);
 
     test::random_values<T> v2(5, gen);
@@ -221,16 +222,41 @@ struct emplace_lvalue_pos_type
 } emplace_lvalue_pos;
 
 // Run the exception tests in various combinations.
+using test::default_generator;
+using test::limited_range;
+using test::generate_collisions;
 
+#ifdef BOOST_UNORDERED_FOA_TESTS
+test_set* test_set_;
+test_map* test_map_;
+
+// clang-format off
+UNORDERED_TEST(insert_exception_test,
+    ((test_set_)(test_map_))
+    ((insert_lvalue)(insert_lvalue_begin)(insert_lvalue_end)
+     (insert_lvalue_pos)(insert_single_item_range)
+     (emplace_lvalue)(emplace_lvalue_begin)(emplace_lvalue_end)
+     (emplace_lvalue_pos)
+    )
+    ((default_generator)(limited_range)(generate_collisions))
+)
+
+UNORDERED_TEST(insert_rehash_exception_test,
+    ((test_set_)(test_map_))
+    ((insert_lvalue)(insert_lvalue_begin)(insert_lvalue_end)
+     (insert_lvalue_pos)(insert_single_item_range)
+     (emplace_lvalue)(emplace_lvalue_begin)(emplace_lvalue_end)
+     (emplace_lvalue_pos)
+    )
+    ((default_generator)(limited_range)(generate_collisions))
+)
+// clang-format on
+#else
 test_set* test_set_;
 test_multiset* test_multiset_;
 test_map* test_map_;
 test_multimap* test_multimap_;
 
-using test::default_generator;
-using test::limited_range;
-using test::generate_collisions;
-
 // clang-format off
 UNORDERED_TEST(insert_exception_test,
     ((test_set_)(test_multiset_)(test_map_)(test_multimap_))
@@ -252,6 +278,7 @@ UNORDERED_TEST(insert_rehash_exception_test,
     ((default_generator)(limited_range)(generate_collisions))
 )
 // clang-format on
+#endif
 
 // Repeat insert tests with pairs
 
@@ -259,8 +286,13 @@ struct pair_emplace_type : inserter_base
 {
   template <typename T, typename Iterator> void operator()(T& x, Iterator it)
   {
+#ifdef BOOST_UNORDERED_FOA_TESTS
+    x.emplace(std::piecewise_construct, std::make_tuple(it->first),
+      std::make_tuple(it->second));
+#else
     x.emplace(boost::unordered::piecewise_construct,
       boost::make_tuple(it->first), boost::make_tuple(it->second));
+#endif
   }
 } pair_emplace;
 
@@ -268,12 +300,34 @@ struct pair_emplace2_type : inserter_base
 {
   template <typename T, typename Iterator> void operator()(T& x, Iterator it)
   {
+#ifdef BOOST_UNORDERED_FOA_TESTS
+    x.emplace_hint(x.begin(), std::piecewise_construct,
+      std::make_tuple(it->first),
+      std::make_tuple(it->second.tag1_, it->second.tag2_));
+#else
     x.emplace_hint(x.begin(), boost::unordered::piecewise_construct,
       boost::make_tuple(it->first),
       boost::make_tuple(it->second.tag1_, it->second.tag2_));
+#endif
   }
 } pair_emplace2;
 
+#ifdef BOOST_UNORDERED_FOA_TESTS
+test_pair_set* test_pair_set_;
+
+// clang-format off
+UNORDERED_TEST(insert_exception_test,
+    ((test_pair_set_)(test_map_))
+    ((pair_emplace)(pair_emplace2))
+    ((default_generator)(limited_range)(generate_collisions))
+)
+UNORDERED_TEST(insert_rehash_exception_test,
+    ((test_pair_set_)(test_map_))
+    ((pair_emplace)(pair_emplace2))
+    ((default_generator)(limited_range)(generate_collisions))
+)
+// clang-format on
+#else
 test_pair_set* test_pair_set_;
 test_pair_multiset* test_pair_multiset_;
 
@@ -289,6 +343,7 @@ UNORDERED_TEST(insert_rehash_exception_test,
     ((default_generator)(limited_range)(generate_collisions))
 )
 // clang-format on
+#endif
 
 // Test inserting using operator[]
 
@@ -393,7 +448,7 @@ template <typename T>
 void insert_range_rehash_exception_test(T*, test::random_generator gen)
 {
   for (int i = 0; i < 5; ++i) {
-    T x;
+    T x(1);
     rehash_prep(x);
 
     test::random_values<T> v2(5, gen);
@@ -401,6 +456,19 @@ void insert_range_rehash_exception_test(T*, test::random_generator gen)
   }
 }
 
+#ifdef BOOST_UNORDERED_FOA_TESTS
+// clang-format off
+UNORDERED_TEST(insert_range_exception_test,
+    ((test_set_)(test_map_))
+    ((default_generator)(limited_range)(generate_collisions))
+)
+
+UNORDERED_TEST(insert_range_rehash_exception_test,
+    ((test_set_)(test_map_))
+    ((default_generator)(limited_range)(generate_collisions))
+)
+// clang-format on
+#else
 // clang-format off
 UNORDERED_TEST(insert_range_exception_test,
     ((test_set_)(test_multiset_)(test_map_)(test_multimap_))
@@ -412,5 +480,6 @@ UNORDERED_TEST(insert_range_rehash_exception_test,
     ((default_generator)(limited_range)(generate_collisions))
 )
 // clang-format on
+#endif
 
 RUN_TESTS()

test/exception/merge_exception_tests.cpp

@@ -1,5 +1,6 @@
 
 // Copyright 2017-2018 Daniel James.
+// Copyright 2022 Christian Mazakas.
 // Distributed under the Boost Software License, Version 1.0. (See accompanying
 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
 
@@ -52,6 +53,53 @@ void merge_exception_test(T1 const*, T2 const*, std::size_t count12, int tag12,
   EXCEPTION_LOOP(merge_exception_test(x, y))
 }
 
+using test::default_generator;
+using test::generate_collisions;
+using test::limited_range;
+
+#ifdef BOOST_UNORDERED_FOA_TESTS
+boost::unordered_flat_set<test::exception::object, test::exception::hash,
+  test::exception::equal_to,
+  test::exception::allocator<test::exception::object> >* test_set_;
+boost::unordered_flat_map<test::exception::object, test::exception::object,
+  test::exception::hash, test::exception::equal_to,
+  test::exception::allocator2<test::exception::object> >* test_map_;
+
+// clang-format off
+UNORDERED_MULTI_TEST(set_merge, merge_exception_test,
+    ((test_set_))
+    ((test_set_))
+    ((0x0000)(0x6400)(0x0064)(0x0a64)(0x3232))
+    ((0x0000)(0x0001)(0x0102))
+    ((default_generator)(limited_range))
+    ((default_generator)(limited_range))
+)
+UNORDERED_MULTI_TEST(map_merge, merge_exception_test,
+    ((test_map_))
+    ((test_map_))
+    ((0x0000)(0x6400)(0x0064)(0x0a64)(0x3232))
+    ((0x0101)(0x0200)(0x0201))
+    ((default_generator)(limited_range))
+    ((default_generator)(limited_range))
+)
+// Run fewer generate_collisions tests, as they're slow.
+UNORDERED_MULTI_TEST(set_merge_collisions, merge_exception_test,
+    ((test_set_))
+    ((test_set_))
+    ((0x0a0a))
+    ((0x0202)(0x0100)(0x0201))
+    ((generate_collisions))
+    ((generate_collisions))
+)
+UNORDERED_MULTI_TEST(map_merge_collisions, merge_exception_test,
+    ((test_map_))
+    ((test_map_))
+    ((0x0a0a))
+    ((0x0000)(0x0002)(0x0102))
+    ((generate_collisions))
+    ((generate_collisions))
+)
+#else
 boost::unordered_set<test::exception::object, test::exception::hash,
   test::exception::equal_to,
   test::exception::allocator<test::exception::object> >* test_set_;
@@ -65,10 +113,6 @@ boost::unordered_multimap<test::exception::object, test::exception::object,
   test::exception::hash, test::exception::equal_to,
   test::exception::allocator2<test::exception::object> >* test_multimap_;
 
-using test::default_generator;
-using test::generate_collisions;
-using test::limited_range;
-
 // clang-format off
 UNORDERED_MULTI_TEST(set_merge, merge_exception_test,
     ((test_set_)(test_multiset_))
@@ -104,5 +148,6 @@ UNORDERED_MULTI_TEST(map_merge_collisions, merge_exception_test,
     ((generate_collisions))
 )
 // clang-format on
+#endif
 
 RUN_TESTS_QUIET()

test/exception/swap_exception_tests.cpp

@@ -1,10 +1,15 @@
 
 // Copyright 2006-2009 Daniel James.
+// Copyright 2022 Christian Mazakas.
 // Distributed under the Boost Software License, Version 1.0. (See accompanying
 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
 
 #include "./containers.hpp"
 
+#if defined(BOOST_UNORDERED_FOA_TESTS)
+#define BOOST_UNORDERED_FOA_WEAK_GUARANTEE_SWAP_EXCEPTIONS_TESTS
+#endif
+
 #include "../helpers/invariants.hpp"
 #include "../helpers/random_values.hpp"
 #include "../helpers/tracker.hpp"