optimized SSE2-based group15

Add msvc RTC to select test targets

.drone.jsonnet

@@ -138,31 +138,217 @@ local windows_pipeline(name, image, environment, arch = "amd64") =
     ),
 
     linux_pipeline(
-        "Linux 20.04 GCC 9* ARM64 32",
+        "Linux 16.04 GCC 5* 32/64",
+        "cppalliance/droneubuntu1604:1",
+        { TOOLSET: 'gcc', COMPILER: 'g++', CXXSTD: '03,11,14', ADDRMD: '32,64' },
+    ),
+
+    linux_pipeline(
+        "Linux 18.04 GCC 6 32/64",
+        "cppalliance/droneubuntu1804:1",
+        { TOOLSET: 'gcc', COMPILER: 'g++-6', CXXSTD: '03,11,14', ADDRMD: '32,64' },
+        "g++-6-multilib",
+    ),
+
+    linux_pipeline(
+        "Linux 18.04 GCC 7* 32/64",
+        "cppalliance/droneubuntu1804:1",
+        { TOOLSET: 'gcc', COMPILER: 'g++', CXXSTD: '03,11,14,17', ADDRMD: '32,64' },
+    ),
+
+    linux_pipeline(
+        "Linux 18.04 GCC 8 32/64",
+        "cppalliance/droneubuntu1804:1",
+        { TOOLSET: 'gcc', COMPILER: 'g++-8', CXXSTD: '03,11,14,17', ADDRMD: '32,64' },
+        "g++-8-multilib",
+    ),
+
+    linux_pipeline(
+        "Linux 20.04 GCC 9* 32/64",
+        "cppalliance/droneubuntu2004:1",
+        { TOOLSET: 'gcc', COMPILER: 'g++', CXXSTD: '03,11,14,17,2a', ADDRMD: '32,64' },
+    ),
+
+    linux_pipeline(
+        "Linux 20.04 GCC 9* ARM64",
         "cppalliance/droneubuntu2004:multiarch",
-        { TOOLSET: 'gcc', COMPILER: 'g++', CXXSTD: '03,11,14,17,2a', ADDRMD: '32' },
+        { TOOLSET: 'gcc', COMPILER: 'g++', CXXSTD: '03,11,14,17,2a' },
         arch="arm64",
     ),
 
     linux_pipeline(
-        "Linux 20.04 GCC 9* ARM64 64",
+        "Linux 20.04 GCC 9* S390x",
         "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' },
+        { TOOLSET: 'gcc', COMPILER: 'g++', CXXSTD: '03,11,14,17,2a' },
         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",
+        "Linux 20.04 GCC 10 32/64",
+        "cppalliance/droneubuntu2004:1",
+        { TOOLSET: 'gcc', COMPILER: 'g++-10', CXXSTD: '03,11,14,17,20', ADDRMD: '32,64' },
+        "g++-10-multilib",
+    ),
+
+    linux_pipeline(
+        "Linux 22.04 GCC 11* 32/64",
+        "cppalliance/droneubuntu2204:1",
+        { TOOLSET: 'gcc', COMPILER: 'g++', CXXSTD: '03,11,14,17,2a', ADDRMD: '32,64' },
+    ),
+
+    linux_pipeline(
+        "Linux 22.04 GCC 12 32 ASAN (03,11,14)",
+        "cppalliance/droneubuntu2204:1",
+        { TOOLSET: 'gcc', COMPILER: 'g++-12', CXXSTD: '03,11,14', ADDRMD: '32' } + asan,
+        "g++-12-multilib",
+    ),
+
+    linux_pipeline(
+        "Linux 22.04 GCC 12 32 ASAN (17,20,2b)",
+        "cppalliance/droneubuntu2204:1",
+        { TOOLSET: 'gcc', COMPILER: 'g++-12', CXXSTD: '17,20,2b', ADDRMD: '32' } + asan,
+        "g++-12-multilib",
+    ),
+
+    linux_pipeline(
+        "Linux 22.04 GCC 12 64 ASAN (03,11,14)",
+        "cppalliance/droneubuntu2204:1",
+        { TOOLSET: 'gcc', COMPILER: 'g++-12', CXXSTD: '03,11,14', ADDRMD: '64' } + asan,
+        "g++-12-multilib",
+    ),
+
+    linux_pipeline(
+        "Linux 22.04 GCC 12 64 ASAN (17,20,2b)",
+        "cppalliance/droneubuntu2204:1",
+        { TOOLSET: 'gcc', COMPILER: 'g++-12', CXXSTD: '17,20,2b', ADDRMD: '64' } + asan,
+        "g++-12-multilib",
+    ),
+
+    linux_pipeline(
+        "Linux 16.04 Clang 3.5",
+        "cppalliance/droneubuntu1604:1",
+        { TOOLSET: 'clang', COMPILER: 'clang++-3.5', CXXSTD: '03,11' },
+        "clang-3.5",
+    ),
+
+    linux_pipeline(
+        "Linux 16.04 Clang 3.6",
+        "cppalliance/droneubuntu1604:1",
+        { TOOLSET: 'clang', COMPILER: 'clang++-3.6', CXXSTD: '03,11,14' },
+        "clang-3.6",
+    ),
+
+    linux_pipeline(
+        "Linux 16.04 Clang 3.7",
+        "cppalliance/droneubuntu1604:1",
+        { TOOLSET: 'clang', COMPILER: 'clang++-3.7', CXXSTD: '03,11,14' },
+        "clang-3.7",
+    ),
+
+    linux_pipeline(
+        "Linux 16.04 Clang 3.8",
+        "cppalliance/droneubuntu1604:1",
+        { TOOLSET: 'clang', COMPILER: 'clang++-3.8', CXXSTD: '03,11,14' },
+        "clang-3.8",
+    ),
+
+    linux_pipeline(
+        "Linux 18.04 Clang 3.9",
+        "cppalliance/droneubuntu1804:1",
+        { TOOLSET: 'clang', COMPILER: 'clang++-3.9', CXXSTD: '03,11,14' },
+        "clang-3.9",
+    ),
+
+    linux_pipeline(
+        "Linux 18.04 Clang 4.0",
+        "cppalliance/droneubuntu1804:1",
+        { TOOLSET: 'clang', COMPILER: 'clang++-4.0', CXXSTD: '03,11,14' },
+        "clang-4.0",
+    ),
+
+    linux_pipeline(
+        "Linux 18.04 Clang 5.0",
+        "cppalliance/droneubuntu1804:1",
+        { TOOLSET: 'clang', COMPILER: 'clang++-5.0', CXXSTD: '03,11,14,1z' },
+        "clang-5.0",
+    ),
+
+    linux_pipeline(
+        "Linux 18.04 Clang 6.0",
+        "cppalliance/droneubuntu1804:1",
+        { TOOLSET: 'clang', COMPILER: 'clang++-6.0', CXXSTD: '03,11,14,17' },
+        "clang-6.0",
+    ),
+
+    linux_pipeline(
+        "Linux 20.04 Clang 7",
+        "cppalliance/droneubuntu2004:1",
+        { TOOLSET: 'clang', COMPILER: 'clang++-7', CXXSTD: '03,11,14,17' },
+        "clang-7",
+    ),
+
+    linux_pipeline(
+        "Linux 20.04 Clang 8",
+        "cppalliance/droneubuntu2004:1",
+        { TOOLSET: 'clang', COMPILER: 'clang++-8', CXXSTD: '03,11,14,17' },
+        "clang-8",
+    ),
+
+    linux_pipeline(
+        "Linux 20.04 Clang 9",
+        "cppalliance/droneubuntu2004:1",
+        { TOOLSET: 'clang', COMPILER: 'clang++-9', CXXSTD: '03,11,14,17,2a' },
+        "clang-9",
+    ),
+
+    linux_pipeline(
+        "Linux 20.04 Clang 10",
+        "cppalliance/droneubuntu2004:1",
+        { TOOLSET: 'clang', COMPILER: 'clang++-10', CXXSTD: '03,11,14,17,2a' },
+        "clang-10",
+    ),
+
+    linux_pipeline(
+        "Linux 20.04 Clang 11",
+        "cppalliance/droneubuntu2004:1",
+        { TOOLSET: 'clang', COMPILER: 'clang++-11', CXXSTD: '03,11,14,17,2a' },
+        "clang-11",
+    ),
+
+    linux_pipeline(
+        "Linux 20.04 Clang 12",
+        "cppalliance/droneubuntu2004:1",
+        { TOOLSET: 'clang', COMPILER: 'clang++-12', CXXSTD: '03,11,14,17,2a' },
+        "clang-12",
+    ),
+
+    linux_pipeline(
+        "Linux 22.04 Clang 13",
+        "cppalliance/droneubuntu2204:1",
+        { TOOLSET: 'clang', COMPILER: 'clang++-13', CXXSTD: '03,11,14,17,20' },
+        "clang-13",
+    ),
+
+    linux_pipeline(
+        "Linux 22.04 Clang 14 UBSAN",
+        "cppalliance/droneubuntu2204:1",
+        { TOOLSET: 'clang', COMPILER: 'clang++-14', CXXSTD: '03,11,14,17,20' } + ubsan,
+        "clang-14",
+    ),
+
+    linux_pipeline(
+        "Linux 22.04 Clang 14 ASAN",
+        "cppalliance/droneubuntu2204:1",
+        { TOOLSET: 'clang', COMPILER: 'clang++-14', CXXSTD: '03,11,14,17,20' } + asan,
+        "clang-14",
+    ),
+
+    linux_pipeline(
+        "Linux 22.04 Clang 15",
+        "cppalliance/droneubuntu2204:1",
+        { TOOLSET: 'clang', COMPILER: 'clang++-15', CXXSTD: '03,11,14,17,20,2b' },
+        "clang-15",
+        ["deb http://apt.llvm.org/jammy/ llvm-toolchain-jammy-15 main"],
     ),
 
     macos_pipeline(
@@ -176,9 +362,27 @@ local windows_pipeline(name, image, environment, arch = "amd64") =
         xcode_version = "13.4.1", osx_version = "monterey",
     ),
 
+    windows_pipeline(
+        "Windows VS2015 msvc-14.0",
+        "cppalliance/dronevs2015",
+        { TOOLSET: 'msvc-14.0', CXXSTD: '14,latest' },
+    ),
+
     windows_pipeline(
         "Windows VS2017 msvc-14.1",
         "cppalliance/dronevs2017",
         { TOOLSET: 'msvc-14.1', CXXSTD: '14,17,latest' },
     ),
+
+    windows_pipeline(
+        "Windows VS2019 msvc-14.2",
+        "cppalliance/dronevs2019",
+        { TOOLSET: 'msvc-14.2', CXXSTD: '14,17,20,latest' },
+    ),
+
+    windows_pipeline(
+        "Windows VS2022 msvc-14.3",
+        "cppalliance/dronevs2022:1",
+        { TOOLSET: 'msvc-14.3', CXXSTD: '14,17,20,latest' },
+    ),
 ]

.github/workflows/ci.yml

@@ -42,45 +42,37 @@ jobs:
       matrix:
         include:
           # 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 }
+          - { compiler: gcc-7,     cxxstd: '03,11,14,17',    os: ubuntu-20.04, install: 'g++-7' }
+          - { compiler: gcc-8,     cxxstd: '03,11,14,17',    os: ubuntu-20.04, install: 'g++-8' }
+          - { compiler: gcc-9,     cxxstd: '03,11,14,17',    os: ubuntu-20.04, install: 'g++-9' }
+          - { compiler: gcc-10,    cxxstd: '03,11,14,17,20', os: ubuntu-22.04, install: 'g++-10' }
+          - { compiler: gcc-11,    cxxstd: '03,11,14,17,20', os: ubuntu-22.04, install: 'g++-11' }
+          - { name: "gcc-12 w/ sanitizers (03,11,14)", sanitize: yes,
+              compiler: gcc-12,    cxxstd: '03,11,14',       os: ubuntu-22.04, ccache_key: "san1" }
+          - { name: "gcc-12 w/ sanitizers (17,20,2b)", sanitize: yes,
+              compiler: gcc-12,    cxxstd: '17,20,2b',       os: ubuntu-22.04, ccache_key: "san2" }
           - { name: Collect coverage, coverage: yes,
-              compiler: gcc-8,     cxxstd: '03,11',          os: ubuntu-20.04, install: 'g++-8-multilib', address-model: '32,64' }
+              compiler: gcc-8,     cxxstd: '03,11',          os: ubuntu-20.04, install: 'g++-8-multilib', address-model: '32,64', ccache_key: "cov" }
 
-          # 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' }
+          # Linux, clang, libc++
+          - { compiler: clang-7,   cxxstd: '03,11,14,17',       os: ubuntu-20.04, stdlib: libc++, install: 'clang-7 libc++-7-dev libc++abi-7-dev' }
+          - { compiler: clang-10,  cxxstd: '03,11,14,17,20',    os: ubuntu-20.04, stdlib: libc++, install: 'clang-10 libc++-10-dev libc++abi-10-dev' }
+          - { compiler: clang-11,  cxxstd: '03,11,14,17,20',    os: ubuntu-22.04, stdlib: libc++, install: 'clang-11 libc++-11-dev libc++abi-11-dev' }
+          # clang-12 doesn't work on ubuntu-22.04, the linker can't find -lunwind for some reason
+          - { name: "clang-12 w/ sanitizers (03,11,14)", sanitize: yes,
+              compiler: clang-12,  cxxstd: '03,11,14',          os: ubuntu-20.04, stdlib: libc++, install: 'clang-12 libc++-12-dev libc++abi-12-dev', ccache_key: "san1" }
+          - { name: "clang-12 w/ sanitizers (17,20,2b)", sanitize: yes,
+              compiler: clang-12,  cxxstd: '17,20,2b',          os: ubuntu-20.04, stdlib: libc++, install: 'clang-12 libc++-12-dev libc++abi-12-dev', ccache_key: "san2" }
+          - { compiler: clang-13,  cxxstd: '03,11,14,17,20,2b', os: ubuntu-22.04, stdlib: libc++, install: 'clang-13 libc++-13-dev libc++abi-13-dev' }
+          - { compiler: clang-14,  cxxstd: '03,11,14,17,20,2b', os: ubuntu-22.04, stdlib: libc++, install: 'clang-14 libc++-14-dev libc++abi-14-dev' }
+          # not using libc++ because of https://github.com/llvm/llvm-project/issues/52771
+          - { name: "clang-14 w/ sanitizers (03,11,14)", sanitize: yes,
+              compiler: clang-14,  cxxstd: '03,11,14',          os: ubuntu-22.04, ccache_key: "san1" }
+          - { name: "clang-14 w/ sanitizers (17,20,2b)", sanitize: yes,
+              compiler: clang-14,  cxxstd: '17,20,2b',          os: ubuntu-22.04, ccache_key: "san2" }
 
           # OSX, clang
-          - { compiler: clang,     cxxstd: '03,11,14,17,2a', os: macos-11, sanitize: yes }
+          - { compiler: clang,     cxxstd: '03,11,14,17,2a',    os: macos-11, sanitize: yes }
 
     timeout-minutes: 120
     runs-on: ${{matrix.os}}
@@ -119,8 +111,8 @@ jobs:
         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}}-
+          key: ${{matrix.os}}-${{matrix.container}}-${{matrix.compiler}}-${{matrix.ccache_key}}-${{github.sha}}
+          restore-keys: ${{matrix.os}}-${{matrix.container}}-${{matrix.compiler}}-${{matrix.ccache_key}}-
 
       - name: Fetch Boost.CI
         uses: actions/checkout@v3
@@ -225,11 +217,13 @@ jobs:
       fail-fast: false
       matrix:
         include:
-          - { 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 }
+          - { toolset: msvc-14.0, cxxstd: '14,latest',       addrmd: '32,64', os: windows-2019, variant: 'debug,release' }
+          - { toolset: msvc-14.2, cxxstd: '14,17,20,latest', addrmd: '32,64', os: windows-2019, variant: 'debug,release' }
+          - { toolset: msvc-14.3, cxxstd: '14,17,20,latest', addrmd: '32,64', os: windows-2022, variant: 'debug,release' }
+          - { toolset: msvc-14.3, cxxstd: '14',              addrmd: '64',    os: windows-2022, variant: 'debug', defines: '_ALLOW_RTCc_IN_STL', cxxflags: '/RTCc'              }
+          - { toolset: msvc-14.3, cxxstd: '14',              addrmd: '32',    os: windows-2022, variant: 'debug', defines: '_ALLOW_RTCc_IN_STL', cxxflags: '"/RTCc /arch:IA32"' }
+          - { toolset: clang-win, cxxstd: '14,17,latest',    addrmd: '32,64', os: windows-2022, variant: 'debug,release' }
+          - { toolset: gcc,       cxxstd: '03,11,14,17,2a',  addrmd: '64',    os: windows-2019, variant: 'debug,release' }
 
     runs-on: ${{matrix.os}}
 
@@ -258,6 +252,9 @@ jobs:
           B2_TOOLSET: ${{matrix.toolset}}
           B2_CXXSTD: ${{matrix.cxxstd}}
           B2_ADDRESS_MODEL: ${{matrix.addrmd}}
+          B2_DEFINES: ${{matrix.defines}}
+          B2_VARIANT: ${{matrix.variant}}
+          B2_CXXFLAGS: ${{matrix.cxxflags}}
 
       - name: Collect coverage
         shell: powershell

benchmark/.gitignore

@@ -0,0 +1,3 @@
+enwik8
+enwik9
+*.exe

benchmark/string.cpp

@@ -3,22 +3,18 @@
 // https://www.boost.org/LICENSE_1_0.txt
 
 #define _SILENCE_CXX17_OLD_ALLOCATOR_MEMBERS_DEPRECATION_WARNING
+#define _SILENCE_CXX20_CISO646_REMOVED_WARNING
 
 #include <boost/unordered_map.hpp>
-#include <boost/multi_index_container.hpp>
-#include <boost/multi_index/hashed_index.hpp>
-#include <boost/multi_index/member.hpp>
+#include <boost/unordered/unordered_flat_map.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"
+#ifdef HAVE_ANKERL_UNORDERED_DENSE
+# include "ankerl/unordered_dense.h"
 #endif
 #include <unordered_map>
 #include <vector>
@@ -266,24 +262,6 @@ template<template<class...> class Map> BOOST_NOINLINE void test( char const* lab
     times.push_back( rec );
 }
 
-// multi_index emulation of unordered_map
-
-template<class K, class V> struct pair
-{
-    K first;
-    mutable V second;
-};
-
-using namespace boost::multi_index;
-
-template<class K, class V> using multi_index_map = multi_index_container<
-  pair<K, V>,
-  indexed_by<
-    hashed_unique< member<pair<K, V>, K, &pair<K, V>::first> >
-  >,
-  ::allocator< pair<K, V> >
->;
-
 // aliases using the counting allocator
 
 template<class K, class V> using allocator_for = ::allocator< std::pair<K const, V> >;
@@ -294,6 +272,9 @@ template<class K, class V> using std_unordered_map =
 template<class K, class V> using boost_unordered_map =
     boost::unordered_map<K, V, boost::hash<K>, std::equal_to<K>, allocator_for<K, V>>;
 
+template<class K, class V> using boost_unordered_flat_map =
+    boost::unordered_flat_map<K, V, boost::hash<K>, std::equal_to<K>, allocator_for<K, V>>;
+
 #ifdef HAVE_ABSEIL
 
 template<class K, class V> using absl_node_hash_map =
@@ -304,23 +285,10 @@ template<class K, class V> using absl_flat_hash_map =
 
 #endif
 
-#ifdef HAVE_TSL_HOPSCOTCH
+#ifdef HAVE_ANKERL_UNORDERED_DENSE
 
-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> >>;
+template<class K, class V> using ankerl_unordered_dense_map =
+    ankerl::unordered_dense::map<K, V, ankerl::unordered_dense::hash<K>, std::equal_to<K>, ::allocator< std::pair<K, V> >>;
 
 #endif
 
@@ -366,7 +334,10 @@ template<> struct fnv1a_hash_impl<64>
     }
 };
 
-struct fnv1a_hash: fnv1a_hash_impl< std::numeric_limits<std::size_t>::digits > {};
+struct fnv1a_hash: fnv1a_hash_impl< std::numeric_limits<std::size_t>::digits >
+{
+    using is_avalanching = void;
+};
 
 template<class K, class V> using std_unordered_map_fnv1a =
 std::unordered_map<K, V, fnv1a_hash, std::equal_to<K>, allocator_for<K, V>>;
@@ -374,13 +345,8 @@ std::unordered_map<K, V, fnv1a_hash, std::equal_to<K>, allocator_for<K, V>>;
 template<class K, class V> using boost_unordered_map_fnv1a =
     boost::unordered_map<K, V, fnv1a_hash, std::equal_to<K>, allocator_for<K, V>>;
 
-template<class K, class V> using multi_index_map_fnv1a = multi_index_container<
-  pair<K, V>,
-  indexed_by<
-    hashed_unique< member<pair<K, V>, K, &pair<K, V>::first>, fnv1a_hash >
-  >,
-  ::allocator< pair<K, V> >
->;
+template<class K, class V> using boost_unordered_flat_map_fnv1a =
+    boost::unordered_flat_map<K, V, fnv1a_hash, std::equal_to<K>, allocator_for<K, V>>;
 
 #ifdef HAVE_ABSEIL
 
@@ -392,23 +358,10 @@ template<class K, class V> using absl_flat_hash_map_fnv1a =
 
 #endif
 
-#ifdef HAVE_TSL_HOPSCOTCH
+#ifdef HAVE_ANKERL_UNORDERED_DENSE
 
-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> >>;
+template<class K, class V> using ankerl_unordered_dense_map_fnv1a =
+    ankerl::unordered_dense::map<K, V, fnv1a_hash, std::equal_to<K>, ::allocator< std::pair<K, V> >>;
 
 #endif
 
@@ -418,65 +371,45 @@ int main()
 {
     init_indices();
 
-#if 0
-
     test<std_unordered_map>( "std::unordered_map" );
     test<boost_unordered_map>( "boost::unordered_map" );
-    test<multi_index_map>( "multi_index_map" );
+    test<boost_unordered_flat_map>( "boost::unordered_flat_map" );
+
+#ifdef HAVE_ANKERL_UNORDERED_DENSE
+
+    test<ankerl_unordered_dense_map>( "ankerl::unordered_dense::map" );
+
+#endif
 
 #ifdef HAVE_ABSEIL
 
     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
-
 #endif
 
     test<std_unordered_map_fnv1a>( "std::unordered_map, FNV-1a" );
     test<boost_unordered_map_fnv1a>( "boost::unordered_map, FNV-1a" );
-    test<multi_index_map_fnv1a>( "multi_index_map, FNV-1a" );
+    test<boost_unordered_flat_map_fnv1a>( "boost::unordered_flat_map, FNV-1a" );
+
+#ifdef HAVE_ANKERL_UNORDERED_DENSE
+
+    test<ankerl_unordered_dense_map_fnv1a>( "ankerl::unordered_dense::map, FNV-1a" );
+
+#endif
 
 #ifdef HAVE_ABSEIL
 
     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( 31 ) << ( x.label_ + ": " ) << std::setw( 5 ) << x.time_ << " ms, " << std::setw( 9 ) << x.bytes_ << " bytes in " << x.count_ << " allocations\n";
+        std::cout << std::setw( 38 ) << ( x.label_ + ": " ) << std::setw( 5 ) << x.time_ << " ms, " << std::setw( 9 ) << x.bytes_ << " bytes in " << x.count_ << " allocations\n";
     }
 }
 

benchmark/string_view.cpp

@@ -3,22 +3,18 @@
 // https://www.boost.org/LICENSE_1_0.txt
 
 #define _SILENCE_CXX17_OLD_ALLOCATOR_MEMBERS_DEPRECATION_WARNING
+#define _SILENCE_CXX20_CISO646_REMOVED_WARNING
 
 #include <boost/unordered_map.hpp>
-#include <boost/multi_index_container.hpp>
-#include <boost/multi_index/hashed_index.hpp>
-#include <boost/multi_index/member.hpp>
+#include <boost/unordered/unordered_flat_map.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"
+#ifdef HAVE_ANKERL_UNORDERED_DENSE
+# include "ankerl/unordered_dense.h"
 #endif
 #include <unordered_map>
 #include <string_view>
@@ -267,24 +263,6 @@ template<template<class...> class Map> BOOST_NOINLINE void test( char const* lab
     times.push_back( rec );
 }
 
-// multi_index emulation of unordered_map
-
-template<class K, class V> struct pair
-{
-    K first;
-    mutable V second;
-};
-
-using namespace boost::multi_index;
-
-template<class K, class V> using multi_index_map = multi_index_container<
-  pair<K, V>,
-  indexed_by<
-    hashed_unique< member<pair<K, V>, K, &pair<K, V>::first> >
-  >,
-  ::allocator< pair<K, V> >
->;
-
 // aliases using the counting allocator
 
 template<class K, class V> using allocator_for = ::allocator< std::pair<K const, V> >;
@@ -295,6 +273,9 @@ template<class K, class V> using std_unordered_map =
 template<class K, class V> using boost_unordered_map =
     boost::unordered_map<K, V, boost::hash<K>, std::equal_to<K>, allocator_for<K, V>>;
 
+template<class K, class V> using boost_unordered_flat_map =
+    boost::unordered_flat_map<K, V, boost::hash<K>, std::equal_to<K>, allocator_for<K, V>>;
+
 #ifdef HAVE_ABSEIL
 
 template<class K, class V> using absl_node_hash_map =
@@ -305,23 +286,10 @@ template<class K, class V> using absl_flat_hash_map =
 
 #endif
 
-#ifdef HAVE_TSL_HOPSCOTCH
+#ifdef HAVE_ANKERL_UNORDERED_DENSE
 
-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> >>;
+template<class K, class V> using ankerl_unordered_dense_map =
+    ankerl::unordered_dense::map<K, V, ankerl::unordered_dense::hash<K>, std::equal_to<K>, ::allocator< std::pair<K, V> >>;
 
 #endif
 
@@ -367,7 +335,10 @@ template<> struct fnv1a_hash_impl<64>
     }
 };
 
-struct fnv1a_hash: fnv1a_hash_impl< std::numeric_limits<std::size_t>::digits > {};
+struct fnv1a_hash: fnv1a_hash_impl< std::numeric_limits<std::size_t>::digits >
+{
+    using is_avalanching = void;
+};
 
 template<class K, class V> using std_unordered_map_fnv1a =
 std::unordered_map<K, V, fnv1a_hash, std::equal_to<K>, allocator_for<K, V>>;
@@ -375,13 +346,8 @@ std::unordered_map<K, V, fnv1a_hash, std::equal_to<K>, allocator_for<K, V>>;
 template<class K, class V> using boost_unordered_map_fnv1a =
     boost::unordered_map<K, V, fnv1a_hash, std::equal_to<K>, allocator_for<K, V>>;
 
-template<class K, class V> using multi_index_map_fnv1a = multi_index_container<
-  pair<K, V>,
-  indexed_by<
-    hashed_unique< member<pair<K, V>, K, &pair<K, V>::first>, fnv1a_hash >
-  >,
-  ::allocator< pair<K, V> >
->;
+template<class K, class V> using boost_unordered_flat_map_fnv1a =
+    boost::unordered_flat_map<K, V, fnv1a_hash, std::equal_to<K>, allocator_for<K, V>>;
 
 #ifdef HAVE_ABSEIL
 
@@ -393,23 +359,10 @@ template<class K, class V> using absl_flat_hash_map_fnv1a =
 
 #endif
 
-#ifdef HAVE_TSL_HOPSCOTCH
+#ifdef HAVE_ANKERL_UNORDERED_DENSE
 
-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> >>;
+template<class K, class V> using ankerl_unordered_dense_map_fnv1a =
+    ankerl::unordered_dense::map<K, V, fnv1a_hash, std::equal_to<K>, ::allocator< std::pair<K, V> >>;
 
 #endif
 
@@ -419,65 +372,45 @@ int main()
 {
     init_indices();
 
-#if 0
-
     test<std_unordered_map>( "std::unordered_map" );
     test<boost_unordered_map>( "boost::unordered_map" );
-    test<multi_index_map>( "multi_index_map" );
+    test<boost_unordered_flat_map>( "boost::unordered_flat_map" );
+
+#ifdef HAVE_ANKERL_UNORDERED_DENSE
+
+    test<ankerl_unordered_dense_map>( "ankerl::unordered_dense::map" );
+
+#endif
 
 #ifdef HAVE_ABSEIL
 
     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
-
 #endif
 
     test<std_unordered_map_fnv1a>( "std::unordered_map, FNV-1a" );
     test<boost_unordered_map_fnv1a>( "boost::unordered_map, FNV-1a" );
-    test<multi_index_map_fnv1a>( "multi_index_map, FNV-1a" );
+    test<boost_unordered_flat_map_fnv1a>( "boost::unordered_flat_map, FNV-1a" );
+
+#ifdef HAVE_ANKERL_UNORDERED_DENSE
+
+    test<ankerl_unordered_dense_map_fnv1a>( "ankerl::unordered_dense::map, FNV-1a" );
+
+#endif
 
 #ifdef HAVE_ABSEIL
 
     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( 31 ) << ( x.label_ + ": " ) << std::setw( 5 ) << x.time_ << " ms, " << std::setw( 9 ) << x.bytes_ << " bytes in " << x.count_ << " allocations\n";
+        std::cout << std::setw( 38 ) << ( x.label_ + ": " ) << std::setw( 5 ) << x.time_ << " ms, " << std::setw( 9 ) << x.bytes_ << " bytes in " << x.count_ << " allocations\n";
     }
 }
 

benchmark/uint32.cpp

@@ -3,11 +3,10 @@
 // https://www.boost.org/LICENSE_1_0.txt
 
 #define _SILENCE_CXX17_OLD_ALLOCATOR_MEMBERS_DEPRECATION_WARNING
+#define _SILENCE_CXX20_CISO646_REMOVED_WARNING
 
 #include <boost/unordered_map.hpp>
-#include <boost/multi_index_container.hpp>
-#include <boost/multi_index/hashed_index.hpp>
-#include <boost/multi_index/member.hpp>
+#include <boost/unordered/unordered_flat_map.hpp>
 #include <boost/endian/conversion.hpp>
 #include <boost/core/detail/splitmix64.hpp>
 #include <boost/config.hpp>
@@ -15,11 +14,8 @@
 # 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"
+#ifdef HAVE_ANKERL_UNORDERED_DENSE
+# include "ankerl/unordered_dense.h"
 #endif
 #include <unordered_map>
 #include <vector>
@@ -283,24 +279,6 @@ template<template<class...> class Map> BOOST_NOINLINE void test( char const* lab
     times.push_back( rec );
 }
 
-// multi_index emulation of unordered_map
-
-template<class K, class V> struct pair
-{
-    K first;
-    mutable V second;
-};
-
-using namespace boost::multi_index;
-
-template<class K, class V> using multi_index_map = multi_index_container<
-  pair<K, V>,
-  indexed_by<
-    hashed_unique< member<pair<K, V>, K, &pair<K, V>::first> >
-  >,
-  ::allocator< pair<K, V> >
->;
-
 // aliases using the counting allocator
 
 template<class K, class V> using allocator_for = ::allocator< std::pair<K const, V> >;
@@ -311,6 +289,9 @@ template<class K, class V> using std_unordered_map =
 template<class K, class V> using boost_unordered_map =
     boost::unordered_map<K, V, boost::hash<K>, std::equal_to<K>, allocator_for<K, V>>;
 
+template<class K, class V> using boost_unordered_flat_map =
+    boost::unordered_flat_map<K, V, boost::hash<K>, std::equal_to<K>, allocator_for<K, V>>;
+
 #ifdef HAVE_ABSEIL
 
 template<class K, class V> using absl_node_hash_map =
@@ -321,23 +302,10 @@ template<class K, class V> using absl_flat_hash_map =
 
 #endif
 
-#ifdef HAVE_TSL_HOPSCOTCH
+#ifdef HAVE_ANKERL_UNORDERED_DENSE
 
-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> >>;
+template<class K, class V> using ankerl_unordered_dense_map =
+    ankerl::unordered_dense::map<K, V, ankerl::unordered_dense::hash<K>, std::equal_to<K>, ::allocator< std::pair<K, V> >>;
 
 #endif
 
@@ -347,34 +315,26 @@ int main()
 
     test<std_unordered_map>( "std::unordered_map" );
     test<boost_unordered_map>( "boost::unordered_map" );
-    test<multi_index_map>( "multi_index_map" );
+    test<boost_unordered_flat_map>( "boost::unordered_flat_map" );
+
+#ifdef HAVE_ANKERL_UNORDERED_DENSE
+
+    test<ankerl_unordered_dense_map>( "ankerl::unordered_dense::map" );
+
+#endif
 
 #ifdef HAVE_ABSEIL
 
     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";
 
     for( auto const& x: times )
     {
-        std::cout << std::setw( 25 ) << ( x.label_ + ": " ) << std::setw( 5 ) << x.time_ << " ms, " << std::setw( 9 ) << x.bytes_ << " bytes in " << x.count_ << " allocations\n";
+        std::cout << std::setw( 30 ) << ( x.label_ + ": " ) << std::setw( 5 ) << x.time_ << " ms, " << std::setw( 9 ) << x.bytes_ << " bytes in " << x.count_ << " allocations\n";
     }
 }
 

benchmark/uint64.cpp

@@ -3,11 +3,10 @@
 // https://www.boost.org/LICENSE_1_0.txt
 
 #define _SILENCE_CXX17_OLD_ALLOCATOR_MEMBERS_DEPRECATION_WARNING
+#define _SILENCE_CXX20_CISO646_REMOVED_WARNING
 
 #include <boost/unordered_map.hpp>
-#include <boost/multi_index_container.hpp>
-#include <boost/multi_index/hashed_index.hpp>
-#include <boost/multi_index/member.hpp>
+#include <boost/unordered/unordered_flat_map.hpp>
 #include <boost/endian/conversion.hpp>
 #include <boost/core/detail/splitmix64.hpp>
 #include <boost/config.hpp>
@@ -15,11 +14,8 @@
 # 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"
+#ifdef HAVE_ANKERL_UNORDERED_DENSE
+# include "ankerl/unordered_dense.h"
 #endif
 #include <unordered_map>
 #include <vector>
@@ -283,24 +279,6 @@ template<template<class...> class Map> BOOST_NOINLINE void test( char const* lab
     times.push_back( rec );
 }
 
-// multi_index emulation of unordered_map
-
-template<class K, class V> struct pair
-{
-    K first;
-    mutable V second;
-};
-
-using namespace boost::multi_index;
-
-template<class K, class V> using multi_index_map = multi_index_container<
-  pair<K, V>,
-  indexed_by<
-    hashed_unique< member<pair<K, V>, K, &pair<K, V>::first> >
-  >,
-  ::allocator< pair<K, V> >
->;
-
 // aliases using the counting allocator
 
 template<class K, class V> using allocator_for = ::allocator< std::pair<K const, V> >;
@@ -311,6 +289,9 @@ template<class K, class V> using std_unordered_map =
 template<class K, class V> using boost_unordered_map =
     boost::unordered_map<K, V, boost::hash<K>, std::equal_to<K>, allocator_for<K, V>>;
 
+template<class K, class V> using boost_unordered_flat_map =
+    boost::unordered_flat_map<K, V, boost::hash<K>, std::equal_to<K>, allocator_for<K, V>>;
+
 #ifdef HAVE_ABSEIL
 
 template<class K, class V> using absl_node_hash_map =
@@ -321,23 +302,10 @@ template<class K, class V> using absl_flat_hash_map =
 
 #endif
 
-#ifdef HAVE_TSL_HOPSCOTCH
+#ifdef HAVE_ANKERL_UNORDERED_DENSE
 
-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> >>;
+template<class K, class V> using ankerl_unordered_dense_map =
+    ankerl::unordered_dense::map<K, V, ankerl::unordered_dense::hash<K>, std::equal_to<K>, ::allocator< std::pair<K, V> >>;
 
 #endif
 
@@ -345,36 +313,38 @@ int main()
 {
     init_indices();
 
+#if defined(BOOST_LIBSTDCXX_VERSION) && __SIZE_WIDTH__ == 32
+
+    // Pathological behavior:
+    // https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104945
+
+#else
+
     test<std_unordered_map>( "std::unordered_map" );
+
+#endif
+
     test<boost_unordered_map>( "boost::unordered_map" );
-    test<multi_index_map>( "multi_index_map" );
+    test<boost_unordered_flat_map>( "boost::unordered_flat_map" );
+
+#ifdef HAVE_ANKERL_UNORDERED_DENSE
+
+    test<ankerl_unordered_dense_map>( "ankerl::unordered_dense::map" );
+
+#endif
 
 #ifdef HAVE_ABSEIL
 
     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";
 
     for( auto const& x: times )
     {
-        std::cout << std::setw( 25 ) << ( x.label_ + ": " ) << std::setw( 5 ) << x.time_ << " ms, " << std::setw( 9 ) << x.bytes_ << " bytes in " << x.count_ << " allocations\n";
+        std::cout << std::setw( 30 ) << ( x.label_ + ": " ) << std::setw( 5 ) << x.time_ << " ms, " << std::setw( 9 ) << x.bytes_ << " bytes in " << x.count_ << " allocations\n";
     }
 }
 

benchmark/uuid.cpp

@@ -0,0 +1,397 @@
+// Copyright 2021, 2022 Peter Dimov.
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#define _SILENCE_CXX17_OLD_ALLOCATOR_MEMBERS_DEPRECATION_WARNING
+#define _SILENCE_CXX20_CISO646_REMOVED_WARNING
+
+#include <boost/unordered_map.hpp>
+#include <boost/unordered/unordered_flat_map.hpp>
+#include <boost/endian/conversion.hpp>
+#include <boost/core/detail/splitmix64.hpp>
+#include <boost/container_hash/hash.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_ANKERL_UNORDERED_DENSE
+# include "ankerl/unordered_dense.h"
+#endif
+#include <unordered_map>
+#include <vector>
+#include <memory>
+#include <cstdint>
+#include <iostream>
+#include <iomanip>
+#include <chrono>
+#include <cstring>
+
+using namespace std::chrono_literals;
+
+static void print_time( std::chrono::steady_clock::time_point & t1, char const* label, std::uint64_t s, std::size_t size )
+{
+    auto t2 = std::chrono::steady_clock::now();
+
+    std::cout << label << ": " << ( t2 - t1 ) / 1ms << " ms (s=" << s << ", size=" << size << ")\n";
+
+    t1 = t2;
+}
+
+constexpr unsigned N = 2'000'000;
+constexpr int K = 10;
+
+struct uuid
+{
+    unsigned char data[ 16 ];
+
+    uuid(): data()
+    {
+    }
+
+    uuid( std::uint64_t low, std::uint64_t high ) noexcept
+    {
+        boost::endian::store_little_u64( data + 0, low );
+        boost::endian::store_little_u64( data + 8, high );
+    }
+
+    inline friend std::size_t hash_value( uuid const& u ) noexcept
+    {
+        std::uint64_t low  = boost::endian::load_little_u64( u.data + 0 );
+        std::uint64_t high = boost::endian::load_little_u64( u.data + 8 );
+
+        std::size_t r = 0;
+
+        boost::hash_combine( r, low );
+        boost::hash_combine( r, high );
+
+        return r;
+    }
+
+    inline friend bool operator==( uuid const& u1, uuid const& u2 ) noexcept
+    {
+        return std::memcmp( u1.data, u2.data, 16 ) == 0;
+    }
+};
+
+namespace std
+{
+
+template<> struct hash< ::uuid >
+{
+    std::size_t operator()( uuid const& u ) const noexcept
+    {
+        return hash_value( u );
+    }
+};
+
+} // namespace std
+
+static std::vector< uuid > indices1, indices2, indices3;
+
+static void init_indices()
+{
+    indices1.push_back( {} );
+
+    for( unsigned i = 1; i <= N*2; ++i )
+    {
+        indices1.push_back( { i, 0 } );
+    }
+
+    indices2.push_back( {} );
+
+    {
+        boost::detail::splitmix64 rng;
+
+        for( unsigned i = 1; i <= N*2; ++i )
+        {
+            indices2.push_back( { rng(), rng() } );
+        }
+    }
+
+    indices3.push_back( {} );
+
+    for( unsigned i = 1; i <= N*2; ++i )
+    {
+        uuid k( i, 0 );
+        std::reverse( k.data + 0, k.data + 16 );
+
+        indices3.push_back( k );
+    }
+}
+
+template<class Map> BOOST_NOINLINE void test_insert( Map& map, std::chrono::steady_clock::time_point & t1 )
+{
+    for( unsigned i = 1; i <= N; ++i )
+    {
+        map.insert( { indices1[ i ], i } );
+    }
+
+    print_time( t1, "Consecutive insert",  0, map.size() );
+
+    for( unsigned i = 1; i <= N; ++i )
+    {
+        map.insert( { indices2[ i ], i } );
+    }
+
+    print_time( t1, "Random insert",  0, map.size() );
+
+    for( unsigned i = 1; i <= N; ++i )
+    {
+        map.insert( { indices3[ i ], i } );
+    }
+
+    print_time( t1, "Consecutive reversed insert",  0, map.size() );
+
+    std::cout << std::endl;
+}
+
+template<class Map> BOOST_NOINLINE void test_lookup( Map& map, std::chrono::steady_clock::time_point & t1 )
+{
+    std::uint64_t s;
+
+    s = 0;
+
+    for( int j = 0; j < K; ++j )
+    {
+        for( unsigned i = 1; i <= N * 2; ++i )
+        {
+            auto it = map.find( indices1[ i ] );
+            if( it != map.end() ) s += it->second;
+        }
+    }
+
+    print_time( t1, "Consecutive lookup",  s, map.size() );
+
+    s = 0;
+
+    for( int j = 0; j < K; ++j )
+    {
+        for( unsigned i = 1; i <= N * 2; ++i )
+        {
+            auto it = map.find( indices2[ i ] );
+            if( it != map.end() ) s += it->second;
+        }
+    }
+
+    print_time( t1, "Random lookup",  s, map.size() );
+
+    s = 0;
+
+    for( int j = 0; j < K; ++j )
+    {
+        for( unsigned i = 1; i <= N * 2; ++i )
+        {
+            auto it = map.find( indices3[ i ] );
+            if( it != map.end() ) s += it->second;
+        }
+    }
+
+    print_time( t1, "Consecutive reversed lookup",  s, map.size() );
+
+    std::cout << std::endl;
+}
+
+template<class Map> BOOST_NOINLINE void test_iteration( Map& map, std::chrono::steady_clock::time_point & t1 )
+{
+    auto it = map.begin();
+
+    while( it != map.end() )
+    {
+        if( it->second & 1 )
+        {
+            if constexpr( std::is_void_v< decltype( map.erase( it ) ) > )
+            {
+                map.erase( it++ );
+            }
+            else
+            {
+                it = map.erase( it );
+            }
+        }
+        else
+        {
+            ++it;
+        }
+    }
+
+    print_time( t1, "Iterate and erase odd elements",  0, map.size() );
+
+    std::cout << std::endl;
+}
+
+template<class Map> BOOST_NOINLINE void test_erase( Map& map, std::chrono::steady_clock::time_point & t1 )
+{
+    for( unsigned i = 1; i <= N; ++i )
+    {
+        map.erase( indices1[ i ] );
+    }
+
+    print_time( t1, "Consecutive erase",  0, map.size() );
+
+    for( unsigned i = 1; i <= N; ++i )
+    {
+        map.erase( indices2[ i ] );
+    }
+
+    print_time( t1, "Random erase",  0, map.size() );
+
+    for( unsigned i = 1; i <= N; ++i )
+    {
+        map.erase( indices3[ i ] );
+    }
+
+    print_time( t1, "Consecutive reversed erase",  0, map.size() );
+
+    std::cout << std::endl;
+}
+
+// counting allocator
+
+static std::size_t s_alloc_bytes = 0;
+static std::size_t s_alloc_count = 0;
+
+template<class T> struct allocator
+{
+    using value_type = T;
+
+    allocator() = default;
+
+    template<class U> allocator( allocator<U> const & ) noexcept
+    {
+    }
+
+    template<class U> bool operator==( allocator<U> const & ) const noexcept
+    {
+        return true;
+    }
+
+    template<class U> bool operator!=( allocator<U> const& ) const noexcept
+    {
+        return false;
+    }
+
+    T* allocate( std::size_t n ) const
+    {
+        s_alloc_bytes += n * sizeof(T);
+        s_alloc_count++;
+
+        return std::allocator<T>().allocate( n );
+    }
+
+    void deallocate( T* p, std::size_t n ) const noexcept
+    {
+        s_alloc_bytes -= n * sizeof(T);
+        s_alloc_count--;
+
+        std::allocator<T>().deallocate( p, n );
+    }
+};
+
+//
+
+struct record
+{
+    std::string label_;
+    long long time_;
+    std::size_t bytes_;
+    std::size_t count_;
+};
+
+static std::vector<record> times;
+
+template<template<class...> class Map> BOOST_NOINLINE void test( char const* label )
+{
+    std::cout << label << ":\n\n";
+
+    s_alloc_bytes = 0;
+    s_alloc_count = 0;
+
+    Map<uuid, std::uint64_t> map;
+
+    auto t0 = std::chrono::steady_clock::now();
+    auto t1 = t0;
+
+    test_insert( map, t1 );
+
+    std::cout << "Memory: " << s_alloc_bytes << " bytes in " << s_alloc_count << " allocations\n\n";
+
+    record rec = { label, 0, s_alloc_bytes, s_alloc_count };
+
+    test_lookup( map, t1 );
+    test_iteration( map, t1 );
+    test_lookup( map, t1 );
+    test_erase( map, t1 );
+
+    auto tN = std::chrono::steady_clock::now();
+    std::cout << "Total: " << ( tN - t0 ) / 1ms << " ms\n\n";
+
+    rec.time_ = ( tN - t0 ) / 1ms;
+    times.push_back( rec );
+}
+
+// aliases using the counting allocator
+
+template<class K, class V> using allocator_for = ::allocator< std::pair<K const, V> >;
+
+template<class K, class V> using std_unordered_map =
+    std::unordered_map<K, V, std::hash<K>, std::equal_to<K>, allocator_for<K, V>>;
+
+template<class K, class V> using boost_unordered_map =
+    boost::unordered_map<K, V, boost::hash<K>, std::equal_to<K>, allocator_for<K, V>>;
+
+template<class K, class V> using boost_unordered_flat_map =
+    boost::unordered_flat_map<K, V, boost::hash<K>, std::equal_to<K>, allocator_for<K, V>>;
+
+#ifdef HAVE_ABSEIL
+
+template<class K, class V> using absl_node_hash_map =
+    absl::node_hash_map<K, V, absl::container_internal::hash_default_hash<K>, absl::container_internal::hash_default_eq<K>, allocator_for<K, V>>;
+
+template<class K, class V> using absl_flat_hash_map =
+    absl::flat_hash_map<K, V, absl::container_internal::hash_default_hash<K>, absl::container_internal::hash_default_eq<K>, allocator_for<K, V>>;
+
+#endif
+
+#ifdef HAVE_ANKERL_UNORDERED_DENSE
+
+template<class K, class V> using ankerl_unordered_dense_map =
+    ankerl::unordered_dense::map<K, V, ankerl::unordered_dense::hash<K>, std::equal_to<K>, ::allocator< std::pair<K, V> >>;
+
+#endif
+
+int main()
+{
+    init_indices();
+
+    test<std_unordered_map>( "std::unordered_map" );
+    test<boost_unordered_map>( "boost::unordered_map" );
+    test<boost_unordered_flat_map>( "boost::unordered_flat_map" );
+
+#ifdef HAVE_ANKERL_UNORDERED_DENSE
+
+    test<ankerl_unordered_dense_map>( "ankerl::unordered_dense::map" );
+
+#endif
+
+#ifdef HAVE_ABSEIL
+
+    test<absl_node_hash_map>( "absl::node_hash_map" );
+    test<absl_flat_hash_map>( "absl::flat_hash_map" );
+
+#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";
+    }
+}
+
+#ifdef HAVE_ABSEIL
+# include "absl/container/internal/raw_hash_set.cc"
+# include "absl/hash/internal/hash.cc"
+# include "absl/hash/internal/low_level_hash.cc"
+# include "absl/hash/internal/city.cc"
+#endif

benchmark/word_count.cpp

@@ -0,0 +1,376 @@
+// Copyright 2021, 2022 Peter Dimov.
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#define _SILENCE_CXX17_OLD_ALLOCATOR_MEMBERS_DEPRECATION_WARNING
+#define _SILENCE_CXX20_CISO646_REMOVED_WARNING
+
+#include <boost/unordered_map.hpp>
+#include <boost/unordered/unordered_flat_map.hpp>
+#include <boost/regex.hpp>
+#ifdef HAVE_ABSEIL
+# include "absl/container/node_hash_map.h"
+# include "absl/container/flat_hash_map.h"
+#endif
+#ifdef HAVE_ANKERL_UNORDERED_DENSE
+# include "ankerl/unordered_dense.h"
+#endif
+#include <unordered_map>
+#include <vector>
+#include <memory>
+#include <cstdint>
+#include <iostream>
+#include <iomanip>
+#include <chrono>
+#include <fstream>
+#include <string_view>
+#include <string>
+
+using namespace std::chrono_literals;
+
+static void print_time( std::chrono::steady_clock::time_point & t1, char const* label, std::size_t s, std::size_t size )
+{
+    auto t2 = std::chrono::steady_clock::now();
+
+    std::cout << label << ": " << ( t2 - t1 ) / 1ms << " ms (s=" << s << ", size=" << size << ")\n";
+
+    t1 = t2;
+}
+
+static std::vector<std::string> words;
+
+static void init_words()
+{
+#if SIZE_MAX > UINT32_MAX
+
+    char const* fn = "enwik9"; // http://mattmahoney.net/dc/textdata
+
+#else
+
+    char const* fn = "enwik8"; // ditto
+
+#endif
+
+    auto t1 = std::chrono::steady_clock::now();
+
+    std::ifstream is( fn );
+    std::string in( std::istreambuf_iterator<char>( is ), std::istreambuf_iterator<char>{} );
+
+    boost::regex re( "[a-zA-Z]+");
+    boost::sregex_token_iterator it( in.begin(), in.end(), re, 0 ), end;
+
+    words.assign( it, end );
+
+    auto t2 = std::chrono::steady_clock::now();
+
+    std::cout << fn << ": " << words.size() << " words, " << ( t2 - t1 ) / 1ms << " ms\n\n";
+}
+
+template<class Map> BOOST_NOINLINE void test_word_count( Map& map, std::chrono::steady_clock::time_point & t1 )
+{
+    std::size_t s = 0;
+
+    for( auto const& word: words )
+    {
+        ++map[ word ];
+        ++s;
+    }
+
+    print_time( t1, "Word count", s, map.size() );
+
+    std::cout << std::endl;
+}
+
+template<class Map> BOOST_NOINLINE void test_contains( Map& map, std::chrono::steady_clock::time_point & t1 )
+{
+    std::size_t s = 0;
+
+    for( auto const& word: words )
+    {
+        std::string_view w2( word );
+        w2.remove_prefix( 1 );
+
+        s += map.contains( w2 );
+    }
+
+    print_time( t1, "Contains", s, map.size() );
+
+    std::cout << std::endl;
+}
+
+template<class Map> BOOST_NOINLINE void test_count( Map& map, std::chrono::steady_clock::time_point & t1 )
+{
+    std::size_t s = 0;
+
+    for( auto const& word: words )
+    {
+        std::string_view w2( word );
+        w2.remove_prefix( 1 );
+
+        s += map.count( w2 );
+    }
+
+    print_time( t1, "Count", s, map.size() );
+
+    std::cout << std::endl;
+}
+
+template<class Map> BOOST_NOINLINE void test_iteration( Map& map, std::chrono::steady_clock::time_point & t1 )
+{
+    std::size_t max = 0;
+    std::string_view word;
+
+    for( auto const& x: map )
+    {
+        if( x.second > max )
+        {
+            word = x.first;
+            max = x.second;
+        }
+    }
+
+    print_time( t1, "Iterate and find max element",  max, map.size() );
+
+    std::cout << std::endl;
+}
+
+// counting allocator
+
+static std::size_t s_alloc_bytes = 0;
+static std::size_t s_alloc_count = 0;
+
+template<class T> struct allocator
+{
+    using value_type = T;
+
+    allocator() = default;
+
+    template<class U> allocator( allocator<U> const & ) noexcept
+    {
+    }
+
+    template<class U> bool operator==( allocator<U> const & ) const noexcept
+    {
+        return true;
+    }
+
+    template<class U> bool operator!=( allocator<U> const& ) const noexcept
+    {
+        return false;
+    }
+
+    T* allocate( std::size_t n ) const
+    {
+        s_alloc_bytes += n * sizeof(T);
+        s_alloc_count++;
+
+        return std::allocator<T>().allocate( n );
+    }
+
+    void deallocate( T* p, std::size_t n ) const noexcept
+    {
+        s_alloc_bytes -= n * sizeof(T);
+        s_alloc_count--;
+
+        std::allocator<T>().deallocate( p, n );
+    }
+};
+
+//
+
+struct record
+{
+    std::string label_;
+    long long time_;
+    std::size_t bytes_;
+    std::size_t count_;
+};
+
+static std::vector<record> times;
+
+template<template<class...> class Map> BOOST_NOINLINE void test( char const* label )
+{
+    std::cout << label << ":\n\n";
+
+    s_alloc_bytes = 0;
+    s_alloc_count = 0;
+
+    Map<std::string_view, std::size_t> map;
+
+    auto t0 = std::chrono::steady_clock::now();
+    auto t1 = t0;
+
+    test_word_count( map, t1 );
+
+    std::cout << "Memory: " << s_alloc_bytes << " bytes in " << s_alloc_count << " allocations\n\n";
+
+    record rec = { label, 0, s_alloc_bytes, s_alloc_count };
+
+    test_contains( map, t1 );
+    test_count( map, t1 );
+    test_iteration( map, t1 );
+
+    auto tN = std::chrono::steady_clock::now();
+    std::cout << "Total: " << ( tN - t0 ) / 1ms << " ms\n\n";
+
+    rec.time_ = ( tN - t0 ) / 1ms;
+    times.push_back( rec );
+}
+
+// aliases using the counting allocator
+
+template<class K, class V> using allocator_for = ::allocator< std::pair<K const, V> >;
+
+template<class K, class V> using std_unordered_map =
+    std::unordered_map<K, V, std::hash<K>, std::equal_to<K>, allocator_for<K, V>>;
+
+template<class K, class V> using boost_unordered_map =
+    boost::unordered_map<K, V, boost::hash<K>, std::equal_to<K>, allocator_for<K, V>>;
+
+template<class K, class V> using boost_unordered_flat_map =
+    boost::unordered_flat_map<K, V, boost::hash<K>, std::equal_to<K>, allocator_for<K, V>>;
+
+#ifdef HAVE_ABSEIL
+
+template<class K, class V> using absl_node_hash_map =
+    absl::node_hash_map<K, V, absl::container_internal::hash_default_hash<K>, absl::container_internal::hash_default_eq<K>, allocator_for<K, V>>;
+
+template<class K, class V> using absl_flat_hash_map =
+    absl::flat_hash_map<K, V, absl::container_internal::hash_default_hash<K>, absl::container_internal::hash_default_eq<K>, allocator_for<K, V>>;
+
+#endif
+
+#ifdef HAVE_ANKERL_UNORDERED_DENSE
+
+template<class K, class V> using ankerl_unordered_dense_map =
+    ankerl::unordered_dense::map<K, V, ankerl::unordered_dense::hash<K>, std::equal_to<K>, ::allocator< std::pair<K, V> >>;
+
+#endif
+
+// fnv1a_hash
+
+template<int Bits> struct fnv1a_hash_impl;
+
+template<> struct fnv1a_hash_impl<32>
+{
+    std::size_t operator()( std::string_view const& s ) const
+    {
+        std::size_t h = 0x811C9DC5u;
+
+        char const * first = s.data();
+        char const * last = first + s.size();
+
+        for( ; first != last; ++first )
+        {
+            h ^= static_cast<unsigned char>( *first );
+            h *= 0x01000193ul;
+        }
+
+        return h;
+    }
+};
+
+template<> struct fnv1a_hash_impl<64>
+{
+    std::size_t operator()( std::string_view const& s ) const
+    {
+        std::size_t h = 0xCBF29CE484222325ull;
+
+        char const * first = s.data();
+        char const * last = first + s.size();
+
+        for( ; first != last; ++first )
+        {
+            h ^= static_cast<unsigned char>( *first );
+            h *= 0x00000100000001B3ull;
+        }
+
+        return h;
+    }
+};
+
+struct fnv1a_hash: fnv1a_hash_impl< std::numeric_limits<std::size_t>::digits >
+{
+    using is_avalanching = void;
+};
+
+template<class K, class V> using std_unordered_map_fnv1a =
+std::unordered_map<K, V, fnv1a_hash, std::equal_to<K>, allocator_for<K, V>>;
+
+template<class K, class V> using boost_unordered_map_fnv1a =
+    boost::unordered_map<K, V, fnv1a_hash, std::equal_to<K>, allocator_for<K, V>>;
+
+template<class K, class V> using boost_unordered_flat_map_fnv1a =
+    boost::unordered_flat_map<K, V, fnv1a_hash, std::equal_to<K>, allocator_for<K, V>>;
+
+#ifdef HAVE_ABSEIL
+
+template<class K, class V> using absl_node_hash_map_fnv1a =
+    absl::node_hash_map<K, V, fnv1a_hash, absl::container_internal::hash_default_eq<K>, allocator_for<K, V>>;
+
+template<class K, class V> using absl_flat_hash_map_fnv1a =
+    absl::flat_hash_map<K, V, fnv1a_hash, absl::container_internal::hash_default_eq<K>, allocator_for<K, V>>;
+
+#endif
+
+#ifdef HAVE_ANKERL_UNORDERED_DENSE
+
+template<class K, class V> using ankerl_unordered_dense_map_fnv1a =
+    ankerl::unordered_dense::map<K, V, fnv1a_hash, std::equal_to<K>, ::allocator< std::pair<K, V> >>;
+
+#endif
+
+//
+
+int main()
+{
+    init_words();
+
+    test<std_unordered_map>( "std::unordered_map" );
+    test<boost_unordered_map>( "boost::unordered_map" );
+    test<boost_unordered_flat_map>( "boost::unordered_flat_map" );
+
+#ifdef HAVE_ANKERL_UNORDERED_DENSE
+
+    test<ankerl_unordered_dense_map>( "ankerl::unordered_dense::map" );
+
+#endif
+
+#ifdef HAVE_ABSEIL
+
+    test<absl_node_hash_map>( "absl::node_hash_map" );
+    test<absl_flat_hash_map>( "absl::flat_hash_map" );
+
+#endif
+
+    test<std_unordered_map_fnv1a>( "std::unordered_map, FNV-1a" );
+    test<boost_unordered_map_fnv1a>( "boost::unordered_map, FNV-1a" );
+    test<boost_unordered_flat_map_fnv1a>( "boost::unordered_flat_map, FNV-1a" );
+
+#ifdef HAVE_ANKERL_UNORDERED_DENSE
+
+    test<ankerl_unordered_dense_map_fnv1a>( "ankerl::unordered_dense::map, FNV-1a" );
+
+#endif
+
+#ifdef HAVE_ABSEIL
+
+    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
+
+    std::cout << "---\n\n";
+
+    for( auto const& x: times )
+    {
+        std::cout << std::setw( 38 ) << ( x.label_ + ": " ) << std::setw( 5 ) << x.time_ << " ms, " << std::setw( 9 ) << x.bytes_ << " bytes in " << x.count_ << " allocations\n";
+    }
+}
+
+#ifdef HAVE_ABSEIL
+# include "absl/container/internal/raw_hash_set.cc"
+# include "absl/hash/internal/hash.cc"
+# include "absl/hash/internal/low_level_hash.cc"
+# include "absl/hash/internal/city.cc"
+#endif

benchmark/word_size.cpp

@@ -0,0 +1,238 @@
+// Copyright 2021, 2022 Peter Dimov.
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#define _SILENCE_CXX17_OLD_ALLOCATOR_MEMBERS_DEPRECATION_WARNING
+#define _SILENCE_CXX20_CISO646_REMOVED_WARNING
+
+#include <boost/unordered_map.hpp>
+#include <boost/unordered/unordered_flat_map.hpp>
+#include <boost/regex.hpp>
+#ifdef HAVE_ABSEIL
+# include "absl/container/node_hash_map.h"
+# include "absl/container/flat_hash_map.h"
+#endif
+#ifdef HAVE_ANKERL_UNORDERED_DENSE
+# include "ankerl/unordered_dense.h"
+#endif
+#include <unordered_map>
+#include <vector>
+#include <memory>
+#include <cstdint>
+#include <iostream>
+#include <iomanip>
+#include <chrono>
+#include <fstream>
+
+using namespace std::chrono_literals;
+
+static void print_time( std::chrono::steady_clock::time_point & t1, char const* label, std::size_t s, std::size_t size )
+{
+    auto t2 = std::chrono::steady_clock::now();
+
+    std::cout << label << ": " << ( t2 - t1 ) / 1ms << " ms (s=" << s << ", size=" << size << ")\n";
+
+    t1 = t2;
+}
+
+static std::vector<std::string> words;
+
+static void init_words()
+{
+#if SIZE_MAX > UINT32_MAX
+
+    char const* fn = "enwik9"; // http://mattmahoney.net/dc/textdata
+
+#else
+
+    char const* fn = "enwik8"; // ditto
+
+#endif
+
+    auto t1 = std::chrono::steady_clock::now();
+
+    std::ifstream is( fn );
+    std::string in( std::istreambuf_iterator<char>( is ), std::istreambuf_iterator<char>{} );
+
+    boost::regex re( "[a-zA-Z]+");
+    boost::sregex_token_iterator it( in.begin(), in.end(), re, 0 ), end;
+
+    words.assign( it, end );
+
+    auto t2 = std::chrono::steady_clock::now();
+
+    std::cout << fn << ": " << words.size() << " words, " << ( t2 - t1 ) / 1ms << " ms\n\n";
+}
+
+template<class Map> BOOST_NOINLINE void test_word_size( Map& map, std::chrono::steady_clock::time_point & t1 )
+{
+    for( auto const& word: words )
+    {
+        ++map[ word.size() ];
+    }
+
+    print_time( t1, "Word size count",  0, map.size() );
+
+    std::cout << std::endl;
+}
+
+template<class Map> BOOST_NOINLINE void test_iteration( Map& map, std::chrono::steady_clock::time_point & t1 )
+{
+    std::size_t s = 0;
+
+    for( auto const& x: map )
+    {
+        s += x.second;
+    }
+
+    print_time( t1, "Iterate and sum counts",  s, map.size() );
+
+    std::cout << std::endl;
+}
+
+// counting allocator
+
+static std::size_t s_alloc_bytes = 0;
+static std::size_t s_alloc_count = 0;
+
+template<class T> struct allocator
+{
+    using value_type = T;
+
+    allocator() = default;
+
+    template<class U> allocator( allocator<U> const & ) noexcept
+    {
+    }
+
+    template<class U> bool operator==( allocator<U> const & ) const noexcept
+    {
+        return true;
+    }
+
+    template<class U> bool operator!=( allocator<U> const& ) const noexcept
+    {
+        return false;
+    }
+
+    T* allocate( std::size_t n ) const
+    {
+        s_alloc_bytes += n * sizeof(T);
+        s_alloc_count++;
+
+        return std::allocator<T>().allocate( n );
+    }
+
+    void deallocate( T* p, std::size_t n ) const noexcept
+    {
+        s_alloc_bytes -= n * sizeof(T);
+        s_alloc_count--;
+
+        std::allocator<T>().deallocate( p, n );
+    }
+};
+
+//
+
+struct record
+{
+    std::string label_;
+    long long time_;
+    std::size_t bytes_;
+    std::size_t count_;
+};
+
+static std::vector<record> times;
+
+template<template<class...> class Map> BOOST_NOINLINE void test( char const* label )
+{
+    std::cout << label << ":\n\n";
+
+    s_alloc_bytes = 0;
+    s_alloc_count = 0;
+
+    Map<std::size_t, std::size_t> map;
+
+    auto t0 = std::chrono::steady_clock::now();
+    auto t1 = t0;
+
+    test_word_size( map, t1 );
+
+    std::cout << "Memory: " << s_alloc_bytes << " bytes in " << s_alloc_count << " allocations\n\n";
+
+    record rec = { label, 0, s_alloc_bytes, s_alloc_count };
+
+    test_iteration( map, t1 );
+
+    auto tN = std::chrono::steady_clock::now();
+    std::cout << "Total: " << ( tN - t0 ) / 1ms << " ms\n\n";
+
+    rec.time_ = ( tN - t0 ) / 1ms;
+    times.push_back( rec );
+}
+
+// aliases using the counting allocator
+
+template<class K, class V> using allocator_for = ::allocator< std::pair<K const, V> >;
+
+template<class K, class V> using std_unordered_map =
+    std::unordered_map<K, V, std::hash<K>, std::equal_to<K>, allocator_for<K, V>>;
+
+template<class K, class V> using boost_unordered_map =
+    boost::unordered_map<K, V, boost::hash<K>, std::equal_to<K>, allocator_for<K, V>>;
+
+template<class K, class V> using boost_unordered_flat_map =
+    boost::unordered_flat_map<K, V, boost::hash<K>, std::equal_to<K>, allocator_for<K, V>>;
+
+#ifdef HAVE_ABSEIL
+
+template<class K, class V> using absl_node_hash_map =
+    absl::node_hash_map<K, V, absl::container_internal::hash_default_hash<K>, absl::container_internal::hash_default_eq<K>, allocator_for<K, V>>;
+
+template<class K, class V> using absl_flat_hash_map =
+    absl::flat_hash_map<K, V, absl::container_internal::hash_default_hash<K>, absl::container_internal::hash_default_eq<K>, allocator_for<K, V>>;
+
+#endif
+
+#ifdef HAVE_ANKERL_UNORDERED_DENSE
+
+template<class K, class V> using ankerl_unordered_dense_map =
+    ankerl::unordered_dense::map<K, V, ankerl::unordered_dense::hash<K>, std::equal_to<K>, ::allocator< std::pair<K, V> >>;
+
+#endif
+
+int main()
+{
+    init_words();
+
+    test<std_unordered_map>( "std::unordered_map" );
+    test<boost_unordered_map>( "boost::unordered_map" );
+    test<boost_unordered_flat_map>( "boost::unordered_flat_map" );
+
+#ifdef HAVE_ANKERL_UNORDERED_DENSE
+
+    test<ankerl_unordered_dense_map>( "ankerl::unordered_dense::map" );
+
+#endif
+
+#ifdef HAVE_ABSEIL
+
+    test<absl_node_hash_map>( "absl::node_hash_map" );
+    test<absl_flat_hash_map>( "absl::flat_hash_map" );
+
+#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";
+    }
+}
+
+#ifdef HAVE_ABSEIL
+# include "absl/container/internal/raw_hash_set.cc"
+# include "absl/hash/internal/hash.cc"
+# include "absl/hash/internal/low_level_hash.cc"
+# include "absl/hash/internal/city.cc"
+#endif