Rewrites for esp-idf

- Removal of direct access to members of uint128_fallback and instead
  create the values at the callsite and pass them via the constructor of
  uint128_fallback on the return statement.

.github/dependabot.yml

@@ -0,0 +1,8 @@
+version: 2
+updates:
+  - package-ecosystem: "github-actions" # Necessary to update action hashs	
+    directory: "/"
+    schedule:
+      interval: "weekly"
+    # Allow up to 3 opened pull requests for github-actions versions
+    open-pull-requests-limit: 3

.github/issue_template.md

@@ -0,0 +1,6 @@
+<!--
+Please make sure that the problem reproduces on the current master before
+submitting an issue.
+If possible please provide a repro on Compiler Explorer:
+https://godbolt.org/z/fxccbh53W.
+-->

.github/pull_request_template.md

@@ -1,6 +1,7 @@
-<!-- Please read the contribution guidelines before submitting a pull request. -->
-<!-- By submitting this pull request, you agree that your contributions are licensed under the {fmt} license,
-     and agree to future changes to the licensing. -->
-<!-- If you're a first-time contributor, please acknowledge it by leaving the statement below. -->
-
-I agree that my contributions are licensed under the {fmt} license, and agree to future changes to the licensing.
+<!--
+Please read the contribution guidelines before submitting a pull request:
+https://github.com/fmtlib/fmt/blob/master/CONTRIBUTING.md.
+By submitting this pull request, you agree to license your contribution(s)
+under the terms outlined in LICENSE.rst and represent that you have the right
+to do so.
+-->

.github/workflows/cifuzz.yml

@@ -0,0 +1,30 @@
+name: CIFuzz
+on: [pull_request]
+
+permissions:
+  contents: read
+
+jobs:
+  Fuzzing:
+    runs-on: ubuntu-latest
+    steps:
+    - name: Build Fuzzers
+      id: build
+      uses: google/oss-fuzz/infra/cifuzz/actions/build_fuzzers@master
+      with:
+        oss-fuzz-project-name: 'fmt'
+        dry-run: false
+        language: c++
+    - name: Run Fuzzers
+      uses: google/oss-fuzz/infra/cifuzz/actions/run_fuzzers@master
+      with:
+        oss-fuzz-project-name: 'fmt'
+        fuzz-seconds: 300
+        dry-run: false
+        language: c++
+    - name: Upload Crash
+      uses: actions/upload-artifact@0b7f8abb1508181956e8e162db84b466c27e18ce # v3.1.2
+      if: failure() && steps.build.outcome == 'success'
+      with:
+        name: artifacts
+        path: ./out/artifacts

.github/workflows/doc.yml

@@ -0,0 +1,35 @@
+name: doc
+
+on: [push, pull_request]
+
+permissions:
+  contents: read
+
+jobs:
+  build:
+    # Use Ubuntu 20.04 because doxygen 1.8.13 from Ubuntu 18.04 is broken.
+    runs-on: ubuntu-20.04
+
+    steps:
+    - uses: actions/checkout@c85c95e3d7251135ab7dc9ce3241c5835cc595a9 # v3.5.3
+
+    - name: Add ubuntu mirrors
+      run: |
+        # Github Actions caching proxy is at times unreliable
+        # see https://github.com/actions/runner-images/issues/7048
+        printf 'http://azure.archive.ubuntu.com/ubuntu\tpriority:1\n' | sudo tee /etc/apt/mirrors.txt
+        curl http://mirrors.ubuntu.com/mirrors.txt | sudo tee --append /etc/apt/mirrors.txt
+        sudo sed -i 's~http://azure.archive.ubuntu.com/ubuntu/~mirror+file:/etc/apt/mirrors.txt~' /etc/apt/sources.list
+
+    - name: Create Build Environment
+      run: |
+        sudo apt update
+        sudo apt install doxygen python3-virtualenv
+        sudo npm install -g less clean-css
+        cmake -E make_directory ${{runner.workspace}}/build
+
+    - name: Build
+      working-directory: ${{runner.workspace}}/build
+      env:
+        KEY: ${{secrets.KEY}}
+      run: $GITHUB_WORKSPACE/support/build-docs.py

.github/workflows/linux.yml

@@ -0,0 +1,111 @@
+name: linux
+
+on: [push, pull_request]
+
+permissions:
+  contents: read
+
+jobs:
+  build:
+    runs-on: ubuntu-20.04
+    strategy:
+      matrix:
+        cxx: [g++-4.8, g++-10, clang++-9]
+        build_type: [Debug, Release]
+        std: [11]
+        include:
+          - cxx: g++-4.8
+            install: sudo apt install g++-4.8
+          - cxx: g++-8
+            build_type: Debug
+            std: 14
+            install: sudo apt install g++-8
+          - cxx: g++-8
+            build_type: Debug
+            std: 17
+            install: sudo apt install g++-8
+          - cxx: g++-9
+            build_type: Debug
+            std: 17
+          - cxx: g++-10
+            build_type: Debug
+            std: 17
+          - cxx: g++-11
+            build_type: Debug
+            std: 20
+            install: sudo apt install g++-11
+          - cxx: clang++-8
+            build_type: Debug
+            std: 17
+            cxxflags: -stdlib=libc++
+            install: sudo apt install clang-8 libc++-8-dev libc++abi-8-dev
+          - cxx: clang++-9
+            install: sudo apt install clang-9
+          - cxx: clang++-9
+            build_type: Debug
+            fuzz: -DFMT_FUZZ=ON -DFMT_FUZZ_LINKMAIN=ON
+            std: 17
+            install: sudo apt install clang-9
+          - cxx: clang++-11
+            build_type: Debug
+            std: 20
+          - cxx: clang++-11
+            build_type: Debug
+            std: 20
+            cxxflags: -stdlib=libc++
+            install: sudo apt install libc++-11-dev libc++abi-11-dev
+          - shared: -DBUILD_SHARED_LIBS=ON
+
+    steps:
+    - uses: actions/checkout@c85c95e3d7251135ab7dc9ce3241c5835cc595a9 # v3.5.3
+
+    - name: Set timezone
+      run: sudo timedatectl set-timezone 'Asia/Yekaterinburg'
+
+    - name: Add repositories for older GCC
+      run: |
+        # Below two repos provide GCC 4.8, 5.5 and 6.4
+        sudo apt-add-repository 'deb http://azure.archive.ubuntu.com/ubuntu/ bionic main'
+        sudo apt-add-repository 'deb http://azure.archive.ubuntu.com/ubuntu/ bionic universe'
+        # Below two repos additionally update GCC 6 to 6.5
+        # sudo apt-add-repository 'deb http://azure.archive.ubuntu.com/ubuntu/ bionic-updates main'
+        # sudo apt-add-repository 'deb http://azure.archive.ubuntu.com/ubuntu/ bionic-updates universe'
+      if: ${{ matrix.cxx == 'g++-4.8' }}
+
+    - name: Add ubuntu mirrors
+      run: |
+        # Github Actions caching proxy is at times unreliable
+        # see https://github.com/actions/runner-images/issues/7048
+        printf 'http://azure.archive.ubuntu.com/ubuntu\tpriority:1\n' | sudo tee /etc/apt/mirrors.txt
+        curl http://mirrors.ubuntu.com/mirrors.txt | sudo tee --append /etc/apt/mirrors.txt
+        sudo sed -i 's~http://azure.archive.ubuntu.com/ubuntu/~mirror+file:/etc/apt/mirrors.txt~' /etc/apt/sources.list
+
+    - name: Create Build Environment
+      run: |
+        sudo apt update
+        ${{matrix.install}}
+        sudo apt install locales-all
+        cmake -E make_directory ${{runner.workspace}}/build
+
+    - name: Configure
+      working-directory: ${{runner.workspace}}/build
+      env:
+        CXX: ${{matrix.cxx}}
+        CXXFLAGS: ${{matrix.cxxflags}}
+      run: |
+        cmake -DCMAKE_BUILD_TYPE=${{matrix.build_type}} ${{matrix.fuzz}} ${{matrix.shared}} \
+              -DCMAKE_CXX_STANDARD=${{matrix.std}} -DFMT_DOC=OFF \
+              -DCMAKE_CXX_VISIBILITY_PRESET=hidden -DCMAKE_VISIBILITY_INLINES_HIDDEN=ON \
+              -DFMT_PEDANTIC=ON -DFMT_WERROR=ON $GITHUB_WORKSPACE
+
+    - name: Build
+      working-directory: ${{runner.workspace}}/build
+      run: |
+        threads=`nproc`
+        cmake --build . --config ${{matrix.build_type}} --parallel $threads
+
+    - name: Test
+      working-directory: ${{runner.workspace}}/build
+      run: ctest -C ${{matrix.build_type}}
+      env:
+        CTEST_OUTPUT_ON_FAILURE: True

.github/workflows/macos.yml

@@ -0,0 +1,55 @@
+name: macos
+
+on: [push, pull_request]
+
+permissions:
+  contents: read
+
+jobs:
+  build:
+    strategy:
+      matrix:
+        os: [macos-11, macos-13]
+        build_type: [Debug, Release]
+        std: [11, 17, 20]
+        exclude:
+          - { os: macos-11, std: 20 }
+          - { os: macos-13, std: 11 }
+          - { os: macos-13, std: 17 }
+        include:
+          - shared: -DBUILD_SHARED_LIBS=ON
+
+    runs-on: '${{ matrix.os }}'
+
+    steps:
+    - uses: actions/checkout@c85c95e3d7251135ab7dc9ce3241c5835cc595a9 # v3.5.3
+
+    - name: Set timezone
+      run: sudo systemsetup -settimezone 'Asia/Yekaterinburg'
+
+    - name: Select Xcode 14.3 (macOS 13)
+      run: sudo xcode-select -s "/Applications/Xcode_14.3.app"
+      if: ${{ matrix.os == 'macos-13' }}
+
+    - name: Create Build Environment
+      run: cmake -E make_directory ${{runner.workspace}}/build
+
+    - name: Configure
+      working-directory: ${{runner.workspace}}/build
+      run: |
+        cmake -DCMAKE_BUILD_TYPE=${{matrix.build_type}} ${{matrix.shared}} \
+              -DCMAKE_CXX_STANDARD=${{matrix.std}} \
+              -DCMAKE_CXX_VISIBILITY_PRESET=hidden -DCMAKE_VISIBILITY_INLINES_HIDDEN=ON \
+              -DFMT_DOC=OFF -DFMT_PEDANTIC=ON -DFMT_WERROR=ON $GITHUB_WORKSPACE
+
+    - name: Build
+      working-directory: ${{runner.workspace}}/build
+      run: |
+        threads=`sysctl -n hw.logicalcpu`
+        cmake --build . --config ${{matrix.build_type}} --parallel $threads
+
+    - name: Test
+      working-directory: ${{runner.workspace}}/build
+      run: ctest -C ${{matrix.build_type}}
+      env:
+        CTEST_OUTPUT_ON_FAILURE: True

.github/workflows/scorecard.yml

@@ -0,0 +1,65 @@
+# This workflow uses actions that are not certified by GitHub. They are provided
+# by a third-party and are governed by separate terms of service, privacy
+# policy, and support documentation.
+
+name: Scorecard supply-chain security
+on:
+  # For Branch-Protection check. Only the default branch is supported. See
+  # https://github.com/ossf/scorecard/blob/main/docs/checks.md#branch-protection
+  branch_protection_rule:
+  # To guarantee Maintained check is occasionally updated. See
+  # https://github.com/ossf/scorecard/blob/main/docs/checks.md#maintained
+  schedule:
+    - cron: '26 14 * * 5'
+  push:
+    branches: [ "master" ]
+
+# Declare default permissions as read only.
+permissions: read-all
+
+jobs:
+  analysis:
+    name: Scorecard analysis
+    runs-on: ubuntu-latest
+    permissions:
+      # Needed to upload the results to code-scanning dashboard.
+      security-events: write
+      # Needed to publish results and get a badge (see publish_results below).
+      id-token: write
+
+    steps:
+      - name: "Checkout code"
+        uses: actions/checkout@c85c95e3d7251135ab7dc9ce3241c5835cc595a9 # v3.5.3
+        with:
+          persist-credentials: false
+
+      - name: "Run analysis"
+        uses: ossf/scorecard-action@08b4669551908b1024bb425080c797723083c031 # v2.2.0
+        with:
+          results_file: results.sarif
+          results_format: sarif
+          # (Optional) "write" PAT token. Uncomment the `repo_token` line below if:
+          # - you want to enable the Branch-Protection check on a *public* repository, or
+          # To create the PAT, follow the steps in https://github.com/ossf/scorecard-action#authentication-with-pat.
+          # repo_token: ${{ secrets.SCORECARD_TOKEN }}
+
+          # Public repositories:
+          #   - Publish results to OpenSSF REST API for easy access by consumers
+          #   - Allows the repository to include the Scorecard badge.
+          #   - See https://github.com/ossf/scorecard-action#publishing-results.
+          publish_results: true
+
+      # Upload the results as artifacts (optional). Commenting out will disable uploads of run results in SARIF
+      # format to the repository Actions tab.
+      - name: "Upload artifact"
+        uses: actions/upload-artifact@0b7f8abb1508181956e8e162db84b466c27e18ce # v3.1.2
+        with:
+          name: SARIF file
+          path: results.sarif
+          retention-days: 5
+
+      # Upload the results to GitHub's code scanning dashboard.
+      - name: "Upload to code-scanning"
+        uses: github/codeql-action/upload-sarif@a09933a12a80f87b87005513f0abb1494c27a716 # v2.21.4
+        with:
+          sarif_file: results.sarif

.github/workflows/windows.yml

@@ -0,0 +1,100 @@
+name: windows
+
+on: [push, pull_request]
+
+permissions:
+  contents: read
+
+jobs:
+  build:
+    runs-on: ${{matrix.os}}
+    strategy:
+      matrix:
+        # windows-2019 has MSVC 2019 installed;
+        # windows-2022 has MSVC 2022 installed:
+        # https://github.com/actions/virtual-environments.
+        os: [windows-2019]
+        platform: [Win32, x64]
+        toolset: [v140, v141, v142]
+        standard: [14, 17, 20]
+        shared: ["", -DBUILD_SHARED_LIBS=ON]
+        build_type: [Debug, Release]
+        exclude:
+          - { toolset: v140, standard: 17 }
+          - { toolset: v140, standard: 20 }
+          - { toolset: v141, standard: 14 }
+          - { toolset: v141, standard: 20 }
+          - { toolset: v142, standard: 14 }
+          - { platform: Win32, toolset: v140 }
+          - { platform: Win32, toolset: v141 }
+          - { platform: Win32, standard: 14 }
+          - { platform: Win32, standard: 20 }
+          - { platform: x64, toolset: v140, shared: -DBUILD_SHARED_LIBS=ON }
+          - { platform: x64, toolset: v141, shared: -DBUILD_SHARED_LIBS=ON }
+          - { platform: x64, standard: 14, shared: -DBUILD_SHARED_LIBS=ON }
+          - { platform: x64, standard: 20, shared: -DBUILD_SHARED_LIBS=ON }
+        include:
+          - os: windows-2022
+            platform: x64
+            toolset: v143
+            build_type: Debug
+            standard: 20
+
+    steps:
+    - uses: actions/checkout@c85c95e3d7251135ab7dc9ce3241c5835cc595a9 # v3.5.3
+
+    - name: Set timezone
+      run: tzutil /s "Ekaterinburg Standard Time"
+
+    - name: Create Build Environment
+      run: cmake -E make_directory ${{runner.workspace}}/build
+
+    - name: Configure
+      # Use a bash shell for $GITHUB_WORKSPACE.
+      shell: bash
+      working-directory: ${{runner.workspace}}/build
+      run: |
+        cmake -A ${{matrix.platform}} -T ${{matrix.toolset}} \
+              -DCMAKE_CXX_STANDARD=${{matrix.standard}} \
+              ${{matrix.shared}} -DCMAKE_BUILD_TYPE=${{matrix.build_type}} \
+              $GITHUB_WORKSPACE
+
+    - name: Build
+      working-directory: ${{runner.workspace}}/build
+      run: |
+        $threads = (Get-CimInstance Win32_ComputerSystem).NumberOfLogicalProcessors
+        cmake --build . --config ${{matrix.build_type}} --parallel $threads
+
+    - name: Test
+      working-directory: ${{runner.workspace}}/build
+      run: ctest -C ${{matrix.build_type}} -V
+      env:
+        CTEST_OUTPUT_ON_FAILURE: True
+
+  mingw:
+    runs-on: windows-latest
+    defaults:
+      run:
+        shell: msys2 {0}
+    strategy:
+      matrix:
+        sys: [ mingw64, ucrt64 ]
+    steps:
+    - name: Set timezone
+      run: tzutil /s "Ekaterinburg Standard Time"
+      shell: cmd
+    - uses: msys2/setup-msys2@7efe20baefed56359985e327d329042cde2434ff # v2
+      with:
+        release: false
+        msystem: ${{matrix.sys}}
+        pacboy: cc:p cmake:p ninja:p lld:p
+    - uses: actions/checkout@c85c95e3d7251135ab7dc9ce3241c5835cc595a9 # v3.5.3
+    - name: Configure
+      run: cmake -B ../build -DBUILD_SHARED_LIBS=ON -DCMAKE_BUILD_TYPE=Debug
+      env: { LDFLAGS: -fuse-ld=lld }
+    - name: Build
+      run: cmake --build ../build
+    - name: Test
+      run: ctest -j `nproc` --test-dir ../build
+      env:
+        CTEST_OUTPUT_ON_FAILURE: True

.gitignore

@@ -9,6 +9,7 @@ gradle/
 gradlew*
 local.properties
 build/
+support/.cxx
 
 bin/
 /_CPack_Packages

.travis.yml

@@ -1,101 +0,0 @@
-language: cpp
-dist: trusty
-sudo: false
-
-os: linux
-
-git:
-  depth: 1
-
-env:
-  global:
-    - secure: |-
-        a1eovNn4uol9won7ghr67eD3/59oeESN+G9bWE+ecI1V6yRseG9whniGhIpC/YfMW/Qz5I
-        5sxSmFjaw9bxCISNwUIrL1O5x2AmRYTnFcXk4dFsUvlZg+WeF/aKyBYCNRM8C2ndbBmtAO
-        o1F2EwFbiso0EmtzhAPs19ujiVxkLn4=
-
-matrix:
-  include:
-      # Documentation
-    - env: BUILD=Doc
-      sudo: required
-      # g++ 6 on Linux with C++14
-    - env: COMPILER=g++-6 BUILD=Debug STANDARD=14
-      compiler: gcc
-      addons:
-        apt:
-          update: true
-          sources:
-            - ubuntu-toolchain-r-test
-          packages:
-            - g++-6
-    - env: COMPILER=g++-6 BUILD=Release STANDARD=14
-      compiler: gcc
-      addons:
-        apt:
-          update: true
-          sources:
-            - ubuntu-toolchain-r-test
-          packages:
-            - g++-6
-     # g++ 8 on Linux with C++17
-    - env: COMPILER=g++-8 BUILD=Debug STANDARD=17
-      compiler: gcc
-      addons:
-        apt:
-          update: true
-          sources:
-            - ubuntu-toolchain-r-test
-          packages:
-            - g++-8
-    - env: COMPILER=g++-8 BUILD=Release STANDARD=17
-      compiler: gcc
-      addons:
-        apt:
-          update: true
-          sources:
-            - ubuntu-toolchain-r-test
-          packages:
-            - g++-8
-
-      # Apple clang on OS X with C++14
-    - env: BUILD=Debug STANDARD=14
-      compiler: clang
-      os: osx
-    - env: BUILD=Release STANDARD=14
-      compiler: clang
-      os: osx
-      # clang 6.0 on Linux with C++14 (builds the fuzzers as well)
-    - env: COMPILER=clang++-6.0 BUILD=Debug STANDARD=14 ENABLE_FUZZING=1
-      compiler: clang
-      addons:
-        apt:
-          update: true
-          packages:
-            - clang-6.0
-          sources:
-            - ubuntu-toolchain-r-test
-            - llvm-toolchain-trusty
-            - llvm-toolchain-trusty-6.0
-      # clang 4.0 on Linux with C++14
-    - env: COMPILER=clang++-4.0 BUILD=Debug STANDARD=11
-      compiler: clang
-      addons:
-        apt:
-          update: true
-          packages:
-            - clang-4.0
-          sources:
-            - ubuntu-toolchain-r-test
-            - llvm-toolchain-trusty
-            - llvm-toolchain-trusty-4.0
-      # g++ 4.8 on Linux with C++11
-    - env: COMPILER=g++-4.8 BUILD=Debug STANDARD=11
-      compiler: gcc
-
-before_script:
-  - if [[ "${TRAVIS_OS_NAME}" == "linux" ]]; then export CXX=${COMPILER}; fi
-  - if [[ "${BUILD}" != "Doc" ]]; then ${CXX} --version; fi
-
-script:
-  - support/travis-build.py

CMakeLists.txt

@@ -1,29 +1,112 @@
-cmake_minimum_required(VERSION 3.1.0)
+if(NOT DEFINED IDF_TARGET)
+cmake_minimum_required(VERSION 3.8...3.26)
 
-# Use newer policies if available, up to most recent tested version of CMake.
-if(${CMAKE_VERSION} VERSION_LESS 3.11)
+# Fallback for using newer policies on CMake <3.12.
+if(${CMAKE_VERSION} VERSION_LESS 3.12)
   cmake_policy(VERSION ${CMAKE_MAJOR_VERSION}.${CMAKE_MINOR_VERSION})
-else()
-  cmake_policy(VERSION 3.11)
 endif()
 
 # Determine if fmt is built as a subproject (using add_subdirectory)
 # or if it is the master project.
-set(MASTER_PROJECT OFF)
-if (CMAKE_CURRENT_SOURCE_DIR STREQUAL CMAKE_SOURCE_DIR)
-  set(MASTER_PROJECT ON)
-  message(STATUS "CMake version: ${CMAKE_VERSION}")
+if (NOT DEFINED FMT_MASTER_PROJECT)
+  set(FMT_MASTER_PROJECT OFF)
+  if (CMAKE_CURRENT_SOURCE_DIR STREQUAL CMAKE_SOURCE_DIR)
+    set(FMT_MASTER_PROJECT ON)
+    message(STATUS "CMake version: ${CMAKE_VERSION}")
+  endif ()
 endif ()
 
 # Joins arguments and places the results in ${result_var}.
 function(join result_var)
-  set(result )
+  set(result "")
   foreach (arg ${ARGN})
     set(result "${result}${arg}")
   endforeach ()
   set(${result_var} "${result}" PARENT_SCOPE)
 endfunction()
 
+# DEPRECATED! Should be merged into add_module_library.
+function(enable_module target)
+  if (MSVC)
+    set(BMI ${CMAKE_CURRENT_BINARY_DIR}/${target}.ifc)
+    target_compile_options(${target}
+      PRIVATE /interface /ifcOutput ${BMI}
+      INTERFACE /reference fmt=${BMI})
+    set_target_properties(${target} PROPERTIES ADDITIONAL_CLEAN_FILES ${BMI})
+    set_source_files_properties(${BMI} PROPERTIES GENERATED ON)
+  endif ()
+endfunction()
+
+# Adds a library compiled with C++20 module support.
+# `enabled` is a CMake variables that specifies if modules are enabled.
+# If modules are disabled `add_module_library` falls back to creating a
+# non-modular library.
+#
+# Usage:
+#   add_module_library(<name> [sources...] FALLBACK [sources...] [IF enabled])
+function(add_module_library name)
+  cmake_parse_arguments(AML "" "IF" "FALLBACK" ${ARGN})
+  set(sources ${AML_UNPARSED_ARGUMENTS})
+
+  add_library(${name})
+  set_target_properties(${name} PROPERTIES LINKER_LANGUAGE CXX)
+
+  if (NOT ${${AML_IF}})
+    # Create a non-modular library.
+    target_sources(${name} PRIVATE ${AML_FALLBACK})
+    return()
+  endif ()
+
+  # Modules require C++20.
+  target_compile_features(${name} PUBLIC cxx_std_20)
+  if (CMAKE_COMPILER_IS_GNUCXX)
+    target_compile_options(${name} PUBLIC -fmodules-ts)
+  endif ()
+
+  # `std` is affected by CMake options and may be higher than C++20.
+  get_target_property(std ${name} CXX_STANDARD)
+
+  if (CMAKE_CXX_COMPILER_ID MATCHES "Clang")
+    set(pcms)
+    foreach (src ${sources})
+      get_filename_component(pcm ${src} NAME_WE)
+      set(pcm ${pcm}.pcm)
+
+      # Propagate -fmodule-file=*.pcm to targets that link with this library.
+      target_compile_options(
+        ${name} PUBLIC -fmodule-file=${CMAKE_CURRENT_BINARY_DIR}/${pcm})
+
+      # Use an absolute path to prevent target_link_libraries prepending -l
+      # to it.
+      set(pcms ${pcms} ${CMAKE_CURRENT_BINARY_DIR}/${pcm})
+      add_custom_command(
+        OUTPUT ${pcm}
+        COMMAND ${CMAKE_CXX_COMPILER}
+                -std=c++${std} -x c++-module --precompile -c
+                -o ${pcm} ${CMAKE_CURRENT_SOURCE_DIR}/${src}
+                "-I$<JOIN:$<TARGET_PROPERTY:${name},INCLUDE_DIRECTORIES>,;-I>"
+        # Required by the -I generator expression above.
+        COMMAND_EXPAND_LISTS
+        DEPENDS ${src})
+    endforeach ()
+
+    # Add .pcm files as sources to make sure they are built before the library.
+    set(sources)
+    foreach (pcm ${pcms})
+      get_filename_component(pcm_we ${pcm} NAME_WE)
+      set(obj ${pcm_we}.o)
+      # Use an absolute path to prevent target_link_libraries prepending -l.
+      set(sources ${sources} ${pcm} ${CMAKE_CURRENT_BINARY_DIR}/${obj})
+      add_custom_command(
+        OUTPUT ${obj}
+        COMMAND ${CMAKE_CXX_COMPILER} $<TARGET_PROPERTY:${name},COMPILE_OPTIONS>
+                -c -o ${obj} ${pcm}
+        DEPENDS ${pcm})
+    endforeach ()
+  endif ()
+  target_sources(${name} PRIVATE ${sources})
+endfunction()
+
 include(CMakeParseArguments)
 
 # Sets a cache variable with a docstring joined from multiple arguments:
@@ -46,7 +129,7 @@ endfunction()
 # Set the default CMAKE_BUILD_TYPE to Release.
 # This should be done before the project command since the latter can set
 # CMAKE_BUILD_TYPE itself (it does so for nmake).
-if (MASTER_PROJECT AND NOT CMAKE_BUILD_TYPE)
+if (FMT_MASTER_PROJECT AND NOT CMAKE_BUILD_TYPE)
   set_verbose(CMAKE_BUILD_TYPE Release CACHE STRING
               "Choose the type of build, options are: None(CMAKE_CXX_FLAGS or "
               "CMAKE_C_FLAGS used) Debug Release RelWithDebInfo MinSizeRel.")
@@ -55,20 +138,35 @@ endif ()
 project(FMT CXX)
 include(GNUInstallDirs)
 set_verbose(FMT_INC_DIR ${CMAKE_INSTALL_INCLUDEDIR} CACHE STRING
-            "Installation directory for include files, a relative path "
-            "that will be joined to ${CMAKE_INSTALL_PREFIX}, or an arbitrary absolute path.")
+            "Installation directory for include files, a relative path that "
+            "will be joined with ${CMAKE_INSTALL_PREFIX} or an absolute path.")
 
 option(FMT_PEDANTIC "Enable extra warnings and expensive tests." OFF)
 option(FMT_WERROR "Halt the compilation with an error on compiler warnings."
        OFF)
 
 # Options that control generation of various targets.
-option(FMT_DOC "Generate the doc target." ${MASTER_PROJECT})
-option(FMT_INSTALL "Generate the install target." ${MASTER_PROJECT})
-option(FMT_TEST "Generate the test target." ${MASTER_PROJECT})
+option(FMT_DOC "Generate the doc target." ${FMT_MASTER_PROJECT})
+option(FMT_INSTALL "Generate the install target." ON)
+option(FMT_TEST "Generate the test target." ${FMT_MASTER_PROJECT})
 option(FMT_FUZZ "Generate the fuzz target." OFF)
 option(FMT_CUDA_TEST "Generate the cuda-test target." OFF)
 option(FMT_OS "Include core requiring OS (Windows/Posix) " ON)
+option(FMT_MODULE "Build a module instead of a traditional library." OFF)
+option(FMT_SYSTEM_HEADERS "Expose headers with marking them as system." OFF)
+
+if (FMT_TEST AND FMT_MODULE)
+  # The tests require {fmt} to be compiled as traditional library
+  message(STATUS "Testing is incompatible with build mode 'module'.")
+endif ()
+set(FMT_SYSTEM_HEADERS_ATTRIBUTE "")
+if (FMT_SYSTEM_HEADERS)
+  set(FMT_SYSTEM_HEADERS_ATTRIBUTE SYSTEM)
+endif ()
+if(CMAKE_SYSTEM_NAME STREQUAL "MSDOS")
+  set(FMT_TEST OFF)
+  message(STATUS "MSDOS is incompatible with gtest")
+endif()
 
 # Get version from core.h
 file(READ include/fmt/core.h core_h)
@@ -86,42 +184,45 @@ message(STATUS "Version: ${FMT_VERSION}")
 message(STATUS "Build type: ${CMAKE_BUILD_TYPE}")
 
 if (NOT CMAKE_RUNTIME_OUTPUT_DIRECTORY)
-  set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/bin)
+  set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}/bin)
 endif ()
 
 set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH}
   "${CMAKE_CURRENT_SOURCE_DIR}/support/cmake")
 
-include(cxx14)
 include(CheckCXXCompilerFlag)
 include(JoinPaths)
 
-list(FIND CMAKE_CXX_COMPILE_FEATURES "cxx_variadic_templates" index)
-if (${index} GREATER -1)
-  # Use cxx_variadic_templates instead of more appropriate cxx_std_11 for
-  # compatibility with older CMake versions.
-  set(FMT_REQUIRED_FEATURES cxx_variadic_templates)
+if (FMT_MASTER_PROJECT AND NOT DEFINED CMAKE_CXX_VISIBILITY_PRESET)
+  set_verbose(CMAKE_CXX_VISIBILITY_PRESET hidden CACHE STRING
+              "Preset for the export of private symbols")
+  set_property(CACHE CMAKE_CXX_VISIBILITY_PRESET PROPERTY STRINGS
+               hidden default)
+endif ()
+
+if (FMT_MASTER_PROJECT AND NOT DEFINED CMAKE_VISIBILITY_INLINES_HIDDEN)
+  set_verbose(CMAKE_VISIBILITY_INLINES_HIDDEN ON CACHE BOOL
+              "Whether to add a compile flag to hide symbols of inline functions")
 endif ()
-message(STATUS "Required features: ${FMT_REQUIRED_FEATURES}")
 
 if (CMAKE_CXX_COMPILER_ID MATCHES "GNU")
   set(PEDANTIC_COMPILE_FLAGS -pedantic-errors -Wall -Wextra -pedantic
       -Wold-style-cast -Wundef
       -Wredundant-decls -Wwrite-strings -Wpointer-arith
       -Wcast-qual -Wformat=2 -Wmissing-include-dirs
-      -Wcast-align -Wnon-virtual-dtor
+      -Wcast-align
       -Wctor-dtor-privacy -Wdisabled-optimization
       -Winvalid-pch -Woverloaded-virtual
-      -Wconversion -Wswitch-enum
-      -Wno-ctor-dtor-privacy -Wno-format-nonliteral -Wno-shadow)
+      -Wconversion -Wundef
+      -Wno-ctor-dtor-privacy -Wno-format-nonliteral)
   if (NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS 4.6)
-      set(PEDANTIC_COMPILE_FLAGS ${PEDANTIC_COMPILE_FLAGS} -Wnoexcept
+      set(PEDANTIC_COMPILE_FLAGS ${PEDANTIC_COMPILE_FLAGS}
          -Wno-dangling-else -Wno-unused-local-typedefs)
   endif ()
   if (NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS 5.0)
       set(PEDANTIC_COMPILE_FLAGS ${PEDANTIC_COMPILE_FLAGS} -Wdouble-promotion
           -Wtrampolines -Wzero-as-null-pointer-constant -Wuseless-cast
-          -Wvector-operation-performance -Wsized-deallocation)
+          -Wvector-operation-performance -Wsized-deallocation -Wshadow)
   endif ()
   if (NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS 6.0)
       set(PEDANTIC_COMPILE_FLAGS ${PEDANTIC_COMPILE_FLAGS} -Wshift-overflow=2
@@ -131,8 +232,9 @@ if (CMAKE_CXX_COMPILER_ID MATCHES "GNU")
 endif ()
 
 if (CMAKE_CXX_COMPILER_ID MATCHES "Clang")
-  set(PEDANTIC_COMPILE_FLAGS -Wall -Wextra -pedantic -Wconversion
-      -Wno-sign-conversion -Wdeprecated -Wweak-vtables)
+  set(PEDANTIC_COMPILE_FLAGS -Wall -Wextra -pedantic -Wconversion -Wundef
+      -Wdeprecated -Wweak-vtables -Wshadow
+      -Wno-gnu-zero-variadic-macro-arguments)
   check_cxx_compiler_flag(-Wzero-as-null-pointer-constant HAS_NULLPTR_WARNING)
   if (HAS_NULLPTR_WARNING)
     set(PEDANTIC_COMPILE_FLAGS ${PEDANTIC_COMPILE_FLAGS}
@@ -146,7 +248,7 @@ if (MSVC)
   set(WERROR_FLAG /WX)
 endif ()
 
-if (MASTER_PROJECT AND CMAKE_GENERATOR MATCHES "Visual Studio")
+if (FMT_MASTER_PROJECT AND CMAKE_GENERATOR MATCHES "Visual Studio")
   # If Microsoft SDK is installed create script run-msbuild.bat that
   # calls SetEnv.cmd to set up build environment and runs msbuild.
   # It is useful when building Visual Studio projects with the SDK
@@ -164,18 +266,6 @@ if (MASTER_PROJECT AND CMAKE_GENERATOR MATCHES "Visual Studio")
     ${CMAKE_MAKE_PROGRAM} -p:FrameworkPathOverride=\"${netfxpath}\" %*")
 endif ()
 
-set(strtod_l_headers stdlib.h)
-if (APPLE)
-  set(strtod_l_headers ${strtod_l_headers} xlocale.h)
-endif ()
-
-include(CheckSymbolExists)
-if (WIN32)
-  check_symbol_exists(_strtod_l "${strtod_l_headers}" HAVE_STRTOD_L)
-else ()
-  check_symbol_exists(strtod_l "${strtod_l_headers}" HAVE_STRTOD_L)
-endif ()
-
 function(add_headers VAR)
   set(headers ${${VAR}})
   foreach (header ${ARGN})
@@ -185,23 +275,20 @@ function(add_headers VAR)
 endfunction()
 
 # Define the fmt library, its includes and the needed defines.
-add_headers(FMT_HEADERS chrono.h color.h compile.h core.h format.h format-inl.h
-                        locale.h os.h ostream.h posix.h printf.h ranges.h)
+add_headers(FMT_HEADERS args.h chrono.h color.h compile.h core.h format.h
+                        format-inl.h os.h ostream.h printf.h ranges.h std.h
+                        xchar.h)
+set(FMT_SOURCES src/format.cc)
 if (FMT_OS)
-  set(FMT_SOURCES src/format.cc src/os.cc)
-else()
-  set(FMT_SOURCES src/format.cc)
+  set(FMT_SOURCES ${FMT_SOURCES} src/os.cc)
 endif ()
 
-add_library(fmt ${FMT_SOURCES} ${FMT_HEADERS} README.rst ChangeLog.rst)
+add_module_library(fmt src/fmt.cc FALLBACK
+                   ${FMT_SOURCES} ${FMT_HEADERS} README.rst ChangeLog.rst
+                   IF FMT_MODULE)
 add_library(fmt::fmt ALIAS fmt)
-
-if (HAVE_STRTOD_L)
-  target_compile_definitions(fmt PUBLIC FMT_LOCALE)
-endif ()
-
-if (MINGW)
-  target_compile_options(fmt PUBLIC "-Wa,-mbig-obj")
+if (FMT_MODULE)
+  enable_module(fmt)
 endif ()
 
 if (FMT_WERROR)
@@ -211,9 +298,13 @@ if (FMT_PEDANTIC)
   target_compile_options(fmt PRIVATE ${PEDANTIC_COMPILE_FLAGS})
 endif ()
 
-target_compile_features(fmt INTERFACE ${FMT_REQUIRED_FEATURES})
+if (cxx_std_11 IN_LIST CMAKE_CXX_COMPILE_FEATURES)
+  target_compile_features(fmt PUBLIC cxx_std_11)
+else ()
+  message(WARNING "Feature cxx_std_11 is unknown for the CXX compiler")
+endif ()
 
-target_include_directories(fmt PUBLIC
+target_include_directories(fmt ${FMT_SYSTEM_HEADERS_ATTRIBUTE} PUBLIC
   $<BUILD_INTERFACE:${PROJECT_SOURCE_DIR}/include>
   $<INSTALL_INTERFACE:${FMT_INC_DIR}>)
 
@@ -221,6 +312,7 @@ set(FMT_DEBUG_POSTFIX d CACHE STRING "Debug library postfix.")
 
 set_target_properties(fmt PROPERTIES
   VERSION ${FMT_VERSION} SOVERSION ${CPACK_PACKAGE_VERSION_MAJOR}
+  PUBLIC_HEADER "${FMT_HEADERS}"
   DEBUG_POSTFIX "${FMT_DEBUG_POSTFIX}")
 
 # Set FMT_LIB_NAME for pkg-config fmt.pc. We cannot use the OUTPUT_NAME target
@@ -231,12 +323,7 @@ if (CMAKE_BUILD_TYPE STREQUAL "Debug")
 endif ()
 
 if (BUILD_SHARED_LIBS)
-  if (UNIX AND NOT APPLE AND NOT ${CMAKE_SYSTEM_NAME} MATCHES "SunOS" AND NOT EMSCRIPTEN)
-    # Fix rpmlint warning:
-    # unused-direct-shlib-dependency /usr/lib/libformat.so.1.1.0 /lib/libm.so.6.
-    target_link_libraries(fmt -Wl,--as-needed)
-  endif ()
-  target_compile_definitions(fmt PRIVATE FMT_EXPORT INTERFACE FMT_SHARED)
+  target_compile_definitions(fmt PRIVATE FMT_LIB_EXPORT INTERFACE FMT_SHARED)
 endif ()
 if (FMT_SAFE_DURATION_CAST)
   target_compile_definitions(fmt PUBLIC FMT_SAFE_DURATION_CAST)
@@ -246,9 +333,9 @@ add_library(fmt-header-only INTERFACE)
 add_library(fmt::fmt-header-only ALIAS fmt-header-only)
 
 target_compile_definitions(fmt-header-only INTERFACE FMT_HEADER_ONLY=1)
-target_compile_features(fmt-header-only INTERFACE ${FMT_REQUIRED_FEATURES})
+target_compile_features(fmt-header-only INTERFACE cxx_std_11)
 
-target_include_directories(fmt-header-only INTERFACE
+target_include_directories(fmt-header-only ${FMT_SYSTEM_HEADERS_ATTRIBUTE} INTERFACE
   $<BUILD_INTERFACE:${PROJECT_SOURCE_DIR}/include>
   $<INSTALL_INTERFACE:${FMT_INC_DIR}>)
 
@@ -256,20 +343,22 @@ target_include_directories(fmt-header-only INTERFACE
 if (FMT_INSTALL)
   include(CMakePackageConfigHelpers)
   set_verbose(FMT_CMAKE_DIR ${CMAKE_INSTALL_LIBDIR}/cmake/fmt CACHE STRING
-              "Installation directory for cmake files, a relative path "
-              "that will be joined to ${CMAKE_INSTALL_PREFIX}, or an arbitrary absolute path.")
+              "Installation directory for cmake files, a relative path that "
+              "will be joined with ${CMAKE_INSTALL_PREFIX} or an absolute "
+              "path.")
   set(version_config ${PROJECT_BINARY_DIR}/fmt-config-version.cmake)
   set(project_config ${PROJECT_BINARY_DIR}/fmt-config.cmake)
   set(pkgconfig ${PROJECT_BINARY_DIR}/fmt.pc)
   set(targets_export_name fmt-targets)
 
   set_verbose(FMT_LIB_DIR ${CMAKE_INSTALL_LIBDIR} CACHE STRING
-              "Installation directory for libraries, a relative path "
-              "that will be joined to ${CMAKE_INSTALL_PREFIX}, or an arbitrary absolute path.")
+              "Installation directory for libraries, a relative path that "
+              "will be joined to ${CMAKE_INSTALL_PREFIX} or an absolute path.")
 
-  set_verbose(FMT_PKGCONFIG_DIR ${CMAKE_INSTALL_LIBDIR}/pkgconfig CACHE PATH
-              "Installation directory for pkgconfig (.pc) files, a relative path "
-              "that will be joined to ${CMAKE_INSTALL_PREFIX}, or an arbitrary absolute path.")
+  set_verbose(FMT_PKGCONFIG_DIR ${CMAKE_INSTALL_LIBDIR}/pkgconfig CACHE STRING
+              "Installation directory for pkgconfig (.pc) files, a relative "
+              "path that will be joined with ${CMAKE_INSTALL_PREFIX} or an "
+              "absolute path.")
 
   # Generate the version, config and target files into the build directory.
   write_basic_package_version_file(
@@ -290,6 +379,14 @@ if (FMT_INSTALL)
     INSTALL_DESTINATION ${FMT_CMAKE_DIR})
 
   set(INSTALL_TARGETS fmt fmt-header-only)
+
+  # Install the library and headers.
+  install(TARGETS ${INSTALL_TARGETS} EXPORT ${targets_export_name}
+          LIBRARY DESTINATION ${FMT_LIB_DIR}
+          ARCHIVE DESTINATION ${FMT_LIB_DIR}
+          PUBLIC_HEADER DESTINATION "${FMT_INC_DIR}/fmt"
+          RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR})
+
   # Use a namespace because CMake provides better diagnostics for namespaced
   # imported targets.
   export(TARGETS ${INSTALL_TARGETS} NAMESPACE fmt::
@@ -302,15 +399,6 @@ if (FMT_INSTALL)
   install(EXPORT ${targets_export_name} DESTINATION ${FMT_CMAKE_DIR}
           NAMESPACE fmt::)
 
-  # Install the library and headers.
-  install(TARGETS ${INSTALL_TARGETS} EXPORT ${targets_export_name}
-          LIBRARY DESTINATION ${FMT_LIB_DIR}
-          ARCHIVE DESTINATION ${FMT_LIB_DIR}
-          RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR})
-
-  install(FILES $<TARGET_PDB_FILE:${INSTALL_TARGETS}>
-          DESTINATION ${FMT_LIB_DIR} OPTIONAL)
-  install(FILES ${FMT_HEADERS} DESTINATION "${FMT_INC_DIR}/fmt")
   install(FILES "${pkgconfig}" DESTINATION "${FMT_PKGCONFIG_DIR}")
 endif ()
 
@@ -326,11 +414,17 @@ endif ()
 # Control fuzzing independent of the unit tests.
 if (FMT_FUZZ)
   add_subdirectory(test/fuzzing)
+
+  # The FMT_FUZZ macro is used to prevent resource exhaustion in fuzzing
+  # mode and make fuzzing practically possible. It is similar to
+  # FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION but uses a different name to
+  # avoid interfering with fuzzing of projects that use {fmt}.
+  # See also https://llvm.org/docs/LibFuzzer.html#fuzzer-friendly-build-mode.
   target_compile_definitions(fmt PUBLIC FMT_FUZZ)
 endif ()
 
 set(gitignore ${PROJECT_SOURCE_DIR}/.gitignore)
-if (MASTER_PROJECT AND EXISTS ${gitignore})
+if (FMT_MASTER_PROJECT AND EXISTS ${gitignore})
   # Get the list of ignored files from .gitignore.
   file (STRINGS ${gitignore} lines)
   list(REMOVE_ITEM lines /doc/html)
@@ -349,3 +443,12 @@ if (MASTER_PROJECT AND EXISTS ${gitignore})
   set(CPACK_RESOURCE_FILE_README ${PROJECT_SOURCE_DIR}/README.rst)
   include(CPack)
 endif ()
+else()
+idf_component_register(
+    SRCS
+        src/format.cc
+    INCLUDE_DIRS
+        include
+)
+set_property(TARGET ${COMPONENT_LIB} PROPERTY CXX_STANDARD 23)
+endif()

CONTRIBUTING.md

@@ -14,4 +14,7 @@ exceptions:
 * snake_case should be used instead of UpperCamelCase for function and type
   names
 
+All documentation must adhere to the [Google Developer Documentation Style
+Guide](https://developers.google.com/style).
+
 Thanks for contributing!

LICENSE.rst

@@ -1,4 +1,4 @@
-Copyright (c) 2012 - present, Victor Zverovich
+Copyright (c) 2012 - present, Victor Zverovich and {fmt} contributors
 
 Permission is hereby granted, free of charge, to any person obtaining
 a copy of this software and associated documentation files (the

README.rst

@@ -1,55 +1,75 @@
-{fmt}
-=====
+.. image:: https://user-images.githubusercontent.com/
+           576385/156254208-f5b743a9-88cf-439d-b0c0-923d53e8d551.png
+   :width: 25%
+   :alt: {fmt}
 
-.. image:: https://travis-ci.org/fmtlib/fmt.png?branch=master
-   :target: https://travis-ci.org/fmtlib/fmt
+.. image:: https://github.com/fmtlib/fmt/workflows/linux/badge.svg
+   :target: https://github.com/fmtlib/fmt/actions?query=workflow%3Alinux
 
-.. image:: https://ci.appveyor.com/api/projects/status/ehjkiefde6gucy1v
-   :target: https://ci.appveyor.com/project/vitaut/fmt
+.. image:: https://github.com/fmtlib/fmt/workflows/macos/badge.svg
+   :target: https://github.com/fmtlib/fmt/actions?query=workflow%3Amacos
 
-.. image:: https://oss-fuzz-build-logs.storage.googleapis.com/badges/libfmt.svg
-   :alt: fmt is continuously fuzzed att oss-fuzz
+.. image:: https://github.com/fmtlib/fmt/workflows/windows/badge.svg
+   :target: https://github.com/fmtlib/fmt/actions?query=workflow%3Awindows
+
+.. image:: https://oss-fuzz-build-logs.storage.googleapis.com/badges/fmt.svg
+   :alt: fmt is continuously fuzzed at oss-fuzz
    :target: https://bugs.chromium.org/p/oss-fuzz/issues/list?\
             colspec=ID%20Type%20Component%20Status%20Proj%20Reported%20Owner%20\
-            Summary&q=proj%3Dlibfmt&can=1
+            Summary&q=proj%3Dfmt&can=1
 
 .. image:: https://img.shields.io/badge/stackoverflow-fmt-blue.svg
    :alt: Ask questions at StackOverflow with the tag fmt
    :target: https://stackoverflow.com/questions/tagged/fmt
 
-**{fmt}** is an open-source formatting library for C++.
-It can be used as a safe and fast alternative to (s)printf and iostreams.
+.. image:: https://api.securityscorecards.dev/projects/github.com/fmtlib/fmt/badge
+   :target: https://securityscorecards.dev/viewer/?uri=github.com/fmtlib/fmt
 
-`Documentation <https://fmt.dev/latest/>`__
+**{fmt}** is an open-source formatting library providing a fast and safe
+alternative to C stdio and C++ iostreams.
+
+If you like this project, please consider donating to one of the funds that
+help victims of the war in Ukraine: https://www.stopputin.net/.
+
+`Documentation <https://fmt.dev>`__
+
+`Cheat Sheets <https://hackingcpp.com/cpp/libs/fmt.html>`__
 
 Q&A: ask questions on `StackOverflow with the tag fmt
 <https://stackoverflow.com/questions/tagged/fmt>`_.
 
+Try {fmt} in `Compiler Explorer <https://godbolt.org/z/Eq5763>`_.
+
 Features
 --------
 
-* Simple `format API <https://fmt.dev/dev/api.html>`_ with positional arguments
+* Simple `format API <https://fmt.dev/latest/api.html>`_ with positional arguments
   for localization
 * Implementation of `C++20 std::format
   <https://en.cppreference.com/w/cpp/utility/format>`__
-* `Format string syntax <https://fmt.dev/dev/syntax.html>`_ similar to the one
-  of Python's
+* `Format string syntax <https://fmt.dev/latest/syntax.html>`_ similar to Python's
   `format <https://docs.python.org/3/library/stdtypes.html#str.format>`_
+* Fast IEEE 754 floating-point formatter with correct rounding, shortness and
+  round-trip guarantees using the `Dragonbox <https://github.com/jk-jeon/dragonbox>`_
+  algorithm
+* Portable Unicode support
 * Safe `printf implementation
-  <https://fmt.dev/latest/api.html#printf-formatting>`_ including
-  the POSIX extension for positional arguments
-* Extensibility: support for user-defined types
+  <https://fmt.dev/latest/api.html#printf-formatting>`_ including the POSIX
+  extension for positional arguments
+* Extensibility: `support for user-defined types
+  <https://fmt.dev/latest/api.html#formatting-user-defined-types>`_
 * High performance: faster than common standard library implementations of
-  `printf <https://en.cppreference.com/w/cpp/io/c/fprintf>`_,
-  iostreams, ``to_string`` and ``to_chars``, see `Speed tests`_ and
-  `Converting a hundred million integers to strings per second
+  ``(s)printf``, iostreams, ``to_string`` and ``to_chars``, see `Speed tests`_
+  and `Converting a hundred million integers to strings per second
   <http://www.zverovich.net/2020/06/13/fast-int-to-string-revisited.html>`_
-* Small code size both in terms of source code (the minimum configuration
-  consists of just three header files, ``core.h``, ``format.h`` and
-  ``format-inl.h``) and compiled code. See `Compile time and code bloat`_
-* Reliability: the library has an extensive set of `unit tests
-  <https://github.com/fmtlib/fmt/tree/master/test>`_ and is continuously fuzzed
-* Safety: the library is fully type safe, errors in format strings can be
+* Small code size both in terms of source code with the minimum configuration
+  consisting of just three files, ``core.h``, ``format.h`` and ``format-inl.h``,
+  and compiled code; see `Compile time and code bloat`_
+* Reliability: the library has an extensive set of `tests
+  <https://github.com/fmtlib/fmt/tree/master/test>`_ and is `continuously fuzzed
+  <https://bugs.chromium.org/p/oss-fuzz/issues/list?colspec=ID%20Type%20
+  Component%20Status%20Proj%20Reported%20Owner%20Summary&q=proj%3Dfmt&can=1>`_
+* Safety: the library is fully type-safe, errors in format strings can be
   reported at compile time, automatic memory management prevents buffer overflow
   errors
 * Ease of use: small self-contained code base, no external dependencies,
@@ -57,18 +77,17 @@ Features
   <https://github.com/fmtlib/fmt/blob/master/LICENSE.rst>`_
 * `Portability <https://fmt.dev/latest/index.html#portability>`_ with
   consistent output across platforms and support for older compilers
-* Clean warning-free codebase even on high warning levels
-  (``-Wall -Wextra -pedantic``)
-* Locale-independence by default
-* Support for wide strings
+* Clean warning-free codebase even on high warning levels such as
+  ``-Wall -Wextra -pedantic``
+* Locale independence by default
 * Optional header-only configuration enabled with the ``FMT_HEADER_ONLY`` macro
 
-See the `documentation <https://fmt.dev/latest/>`_ for more details.
+See the `documentation <https://fmt.dev>`_ for more details.
 
 Examples
 --------
 
-Print ``Hello, world!`` to ``stdout``:
+**Print to stdout** (`run <https://godbolt.org/z/Tevcjh>`_)
 
 .. code:: c++
 
@@ -78,100 +97,95 @@ Print ``Hello, world!`` to ``stdout``:
       fmt::print("Hello, world!\n");
     }
 
-Format a string:
+**Format a string** (`run <https://godbolt.org/z/oK8h33>`_)
 
 .. code:: c++
 
     std::string s = fmt::format("The answer is {}.", 42);
     // s == "The answer is 42."
 
-Format a string using positional arguments:
+**Format a string using positional arguments** (`run <https://godbolt.org/z/Yn7Txe>`_)
 
 .. code:: c++
 
     std::string s = fmt::format("I'd rather be {1} than {0}.", "right", "happy");
     // s == "I'd rather be happy than right."
 
-Print a chrono duration:
+**Print chrono durations** (`run <https://godbolt.org/z/K8s4Mc>`_)
 
 .. code:: c++
 
     #include <fmt/chrono.h>
 
     int main() {
-      using namespace std::chrono_literals;
-      fmt::print("Elapsed time: {}", 42ms);
+      using namespace std::literals::chrono_literals;
+      fmt::print("Default format: {} {}\n", 42s, 100ms);
+      fmt::print("strftime-like format: {:%H:%M:%S}\n", 3h + 15min + 30s);
     }
 
-prints "Elapsed time: 42ms".
+Output::
 
-Check a format string at compile time:
+    Default format: 42s 100ms
+    strftime-like format: 03:15:30
+
+**Print a container** (`run <https://godbolt.org/z/MxM1YqjE7>`_)
 
 .. code:: c++
 
-    // test.cc
-    #include <fmt/format.h>
-    std::string s = format(FMT_STRING("{:d}"), "hello");
+    #include <vector>
+    #include <fmt/ranges.h>
 
-gives a compile-time error because ``d`` is an invalid format specifier for a
-string.
-
-Use {fmt} as a safe portable replacement for ``itoa``
-(`godbolt <https://godbolt.org/g/NXmpU4>`_):
-
-.. code:: c++
-
-    fmt::memory_buffer buf;
-    format_to(buf, "{}", 42);    // replaces itoa(42, buffer, 10)
-    format_to(buf, "{:x}", 42);  // replaces itoa(42, buffer, 16)
-    // access the string with to_string(buf) or buf.data()
-
-Format objects of user-defined types via a simple `extension API
-<https://fmt.dev/latest/api.html#formatting-user-defined-types>`_:
-
-.. code:: c++
-
-    #include <fmt/format.h>
-
-    struct date {
-      int year, month, day;
-    };
-
-    template <>
-    struct fmt::formatter<date> {
-      constexpr auto parse(format_parse_context& ctx) { return ctx.begin(); }
-
-      template <typename FormatContext>
-      auto format(const date& d, FormatContext& ctx) {
-        return format_to(ctx.out(), "{}-{}-{}", d.year, d.month, d.day);
-      }
-    };
-
-    std::string s = fmt::format("The date is {}", date{2012, 12, 9});
-    // s == "The date is 2012-12-9"
-
-Create your own functions similar to `format
-<https://fmt.dev/latest/api.html#format>`_ and
-`print <https://fmt.dev/latest/api.html#print>`_
-which take arbitrary arguments (`godbolt <https://godbolt.org/g/MHjHVf>`_):
-
-.. code:: c++
-
-    // Prints formatted error message.
-    void vreport_error(const char* format, fmt::format_args args) {
-      fmt::print("Error: ");
-      fmt::vprint(format, args);
-    }
-    template <typename... Args>
-    void report_error(const char* format, const Args & ... args) {
-      vreport_error(format, fmt::make_format_args(args...));
+    int main() {
+      std::vector<int> v = {1, 2, 3};
+      fmt::print("{}\n", v);
     }
 
-    report_error("file not found: {}", path);
+Output::
 
-Note that ``vreport_error`` is not parameterized on argument types which can
-improve compile times and reduce code size compared to a fully parameterized
-version.
+    [1, 2, 3]
+
+**Check a format string at compile time**
+
+.. code:: c++
+
+    std::string s = fmt::format("{:d}", "I am not a number");
+
+This gives a compile-time error in C++20 because ``d`` is an invalid format
+specifier for a string.
+
+**Write a file from a single thread**
+
+.. code:: c++
+
+    #include <fmt/os.h>
+
+    int main() {
+      auto out = fmt::output_file("guide.txt");
+      out.print("Don't {}", "Panic");
+    }
+
+This can be `5 to 9 times faster than fprintf
+<http://www.zverovich.net/2020/08/04/optimal-file-buffer-size.html>`_.
+
+**Print with colors and text styles**
+
+.. code:: c++
+
+    #include <fmt/color.h>
+
+    int main() {
+      fmt::print(fg(fmt::color::crimson) | fmt::emphasis::bold,
+                 "Hello, {}!\n", "world");
+      fmt::print(fg(fmt::color::floral_white) | bg(fmt::color::slate_gray) |
+                 fmt::emphasis::underline, "Hello, {}!\n", "мир");
+      fmt::print(fg(fmt::color::steel_blue) | fmt::emphasis::italic,
+                 "Hello, {}!\n", "世界");
+    }
+
+Output on a modern terminal:
+
+.. image:: https://user-images.githubusercontent.com/
+           576385/88485597-d312f600-cf2b-11ea-9cbe-61f535a86e28.png
 
 Benchmarks
 ----------
@@ -182,28 +196,30 @@ Speed tests
 ================= ============= ===========
 Library           Method        Run Time, s
 ================= ============= ===========
-libc              printf          1.04
-libc++            std::ostream    3.05
-{fmt} 6.1.1       fmt::print      0.75
-Boost Format 1.67 boost::format   7.24
-Folly Format      folly::format   2.23
+libc              printf          0.91
+libc++            std::ostream    2.49
+{fmt} 9.1         fmt::print      0.74
+Boost Format 1.80 boost::format   6.26
+Folly Format      folly::format   1.87
 ================= ============= ===========
 
-{fmt} is the fastest of the benchmarked methods, ~35% faster than ``printf``.
+{fmt} is the fastest of the benchmarked methods, ~20% faster than ``printf``.
 
 The above results were generated by building ``tinyformat_test.cpp`` on macOS
-10.14.6 with ``clang++ -O3 -DNDEBUG -DSPEED_TEST -DHAVE_FORMAT``, and taking the
+12.6.1 with ``clang++ -O3 -DNDEBUG -DSPEED_TEST -DHAVE_FORMAT``, and taking the
 best of three runs. In the test, the format string ``"%0.10f:%04d:%+g:%s:%p:%c:%%\n"``
 or equivalent is filled 2,000,000 times with output sent to ``/dev/null``; for
 further details refer to the `source
-<https://github.com/fmtlib/format-benchmark/blob/master/tinyformat_test.cpp>`_.
+<https://github.com/fmtlib/format-benchmark/blob/master/src/tinyformat-test.cc>`_.
 
-{fmt} is up to 10x faster than ``std::ostringstream`` and ``sprintf`` on
-floating-point formatting (`dtoa-benchmark <https://github.com/fmtlib/dtoa-benchmark>`_)
-and faster than `double-conversion <https://github.com/google/double-conversion>`_:
+{fmt} is up to 20-30x faster than ``std::ostringstream`` and ``sprintf`` on
+IEEE754 ``float`` and ``double`` formatting (`dtoa-benchmark <https://github.com/fmtlib/dtoa-benchmark>`_)
+and faster than `double-conversion <https://github.com/google/double-conversion>`_ and
+`ryu <https://github.com/ulfjack/ryu>`_:
 
-.. image:: https://user-images.githubusercontent.com/576385/69767160-cdaca400-112f-11ea-9fc5-347c9f83caad.png
-   :target: https://fmt.dev/unknown_mac64_clang10.0.html
+.. image:: https://user-images.githubusercontent.com/576385/
+           95684665-11719600-0ba8-11eb-8e5b-972ff4e49428.png
+   :target: https://fmt.dev/unknown_mac64_clang12.0.html
 
 Compile time and code bloat
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -213,7 +229,7 @@ The script `bloat-test.py
 from `format-benchmark <https://github.com/fmtlib/format-benchmark>`_
 tests compile time and code bloat for nontrivial projects.
 It generates 100 translation units and uses ``printf()`` or its alternative
-five times in each to simulate a medium sized project.  The resulting
+five times in each to simulate a medium-sized project.  The resulting
 executable size and compile time (Apple LLVM version 8.1.0 (clang-802.0.42),
 macOS Sierra, best of three) is shown in the following tables.
 
@@ -234,7 +250,7 @@ As you can see, {fmt} has 60% less overhead in terms of resulting binary code
 size compared to iostreams and comes pretty close to ``printf``. Boost Format
 and Folly Format have the largest overheads.
 
-``printf+string`` is the same as ``printf`` but with extra ``<string>``
+``printf+string`` is the same as ``printf`` but with an extra ``<string>``
 include to measure the overhead of the latter.
 
 **Non-optimized build**
@@ -250,14 +266,14 @@ Boost Format             54.1                  365                303
 Folly Format             79.9                  445                430
 ============= =============== ==================== ==================
 
-``libc``, ``lib(std)c++`` and ``libfmt`` are all linked as shared libraries to
+``libc``, ``lib(std)c++``, and ``libfmt`` are all linked as shared libraries to
 compare formatting function overhead only. Boost Format is a
 header-only library so it doesn't provide any linkage options.
 
 Running the tests
 ~~~~~~~~~~~~~~~~~
 
-Please refer to `Building the library`__ for the instructions on how to build
+Please refer to `Building the library`__ for instructions on how to build
 the library and run the unit tests.
 
 __ https://fmt.dev/latest/usage.html#building-the-library
@@ -278,34 +294,49 @@ Then you can run the speed test::
 or the bloat test::
 
     $ make bloat-test
+    
+Migrating code
+--------------
+
+`clang-tidy <https://clang.llvm.org/extra/clang-tidy/>`_ v17 (not yet
+released) provides the `modernize-use-std-print
+<https://clang.llvm.org/extra/clang-tidy/checks/modernize/use-std-print.html>`_
+check that is capable of converting occurrences of ``printf`` and
+``fprintf`` to ``fmt::print`` if configured to do so. (By default it
+converts to ``std::print``.)
 
 Projects using this library
 ---------------------------
 
-* `0 A.D. <https://play0ad.com/>`_: A free, open-source, cross-platform
+* `0 A.D. <https://play0ad.com/>`_: a free, open-source, cross-platform
   real-time strategy game
 
 * `AMPL/MP <https://github.com/ampl/mp>`_:
-  An open-source library for mathematical programming
+  an open-source library for mathematical programming
 
 * `Aseprite <https://github.com/aseprite/aseprite>`_:
-  Animated sprite editor & pixel art tool 
+  animated sprite editor & pixel art tool 
 
-* `AvioBook <https://www.aviobook.aero/en>`_: A comprehensive aircraft
+* `AvioBook <https://www.aviobook.aero/en>`_: a comprehensive aircraft
   operations suite
   
-* `Celestia <https://celestia.space/>`_: Real-time 3D visualization of space
+* `Blizzard Battle.net <https://battle.net/>`_: an online gaming platform
+  
+* `Celestia <https://celestia.space/>`_: real-time 3D visualization of space
 
-* `Ceph <https://ceph.com/>`_: A scalable distributed storage system
+* `Ceph <https://ceph.com/>`_: a scalable distributed storage system
 
-* `ccache <https://ccache.dev/>`_: A compiler cache
+* `ccache <https://ccache.dev/>`_: a compiler cache
 
-* `ClickHouse <https://github.com/ClickHouse/ClickHouse>`_: analytical database management system
+* `ClickHouse <https://github.com/ClickHouse/ClickHouse>`_: an analytical database
+  management system
+  
+* `Contour <https://github.com/contour-terminal/contour/>`_: a modern terminal emulator
 
-* `CUAUV <http://cuauv.org/>`_: Cornell University's autonomous underwater
+* `CUAUV <https://cuauv.org/>`_: Cornell University's autonomous underwater
   vehicle
 
-* `Drake <https://drake.mit.edu/>`_: A planning, control, and analysis toolbox
+* `Drake <https://drake.mit.edu/>`_: a planning, control, and analysis toolbox
   for nonlinear dynamical systems (MIT)
 
 * `Envoy <https://lyft.github.io/envoy/>`_: C++ L7 proxy and communication bus
@@ -313,71 +344,92 @@ Projects using this library
 
 * `FiveM <https://fivem.net/>`_: a modification framework for GTA V
 
+* `fmtlog <https://github.com/MengRao/fmtlog>`_: a performant fmtlib-style
+  logging library with latency in nanoseconds
+
 * `Folly <https://github.com/facebook/folly>`_: Facebook open-source library
 
+* `GemRB <https://gemrb.org/>`_: a portable open-source implementation of
+  Bioware’s Infinity Engine
+
+* `Grand Mountain Adventure
+  <https://store.steampowered.com/app/1247360/Grand_Mountain_Adventure/>`_:
+  a beautiful open-world ski & snowboarding game
+
 * `HarpyWar/pvpgn <https://github.com/pvpgn/pvpgn-server>`_:
   Player vs Player Gaming Network with tweaks
 
-* `KBEngine <https://kbengine.org/>`_: An open-source MMOG server engine
+* `KBEngine <https://github.com/kbengine/kbengine>`_: an open-source MMOG server
+  engine
 
-* `Keypirinha <https://keypirinha.com/>`_: A semantic launcher for Windows
+* `Keypirinha <https://keypirinha.com/>`_: a semantic launcher for Windows
 
-* `Kodi <https://kodi.tv/>`_ (formerly xbmc): Home theater software
+* `Kodi <https://kodi.tv/>`_ (formerly xbmc): home theater software
 
-* `Knuth <https://kth.cash/>`_: High-performance Bitcoin full-node
+* `Knuth <https://kth.cash/>`_: high-performance Bitcoin full-node
+
+* `libunicode <https://github.com/contour-terminal/libunicode/>`_: a modern C++17 Unicode library
+
+* `MariaDB <https://mariadb.org/>`_: relational database management system
 
 * `Microsoft Verona <https://github.com/microsoft/verona>`_:
-  Research programming language for concurrent ownership
+  research programming language for concurrent ownership
 
-* `MongoDB <https://mongodb.com/>`_: Distributed document database
+* `MongoDB <https://mongodb.com/>`_: distributed document database
 
-* `MongoDB Smasher <https://github.com/duckie/mongo_smasher>`_: A small tool to
+* `MongoDB Smasher <https://github.com/duckie/mongo_smasher>`_: a small tool to
   generate randomized datasets
 
-* `OpenSpace <https://openspaceproject.com/>`_: An open-source
+* `OpenSpace <https://openspaceproject.com/>`_: an open-source
   astrovisualization framework
 
 * `PenUltima Online (POL) <https://www.polserver.com/>`_:
-  An MMO server, compatible with most Ultima Online clients
+  an MMO server, compatible with most Ultima Online clients
 
-* `PyTorch <https://github.com/pytorch/pytorch>`_: An open-source machine
+* `PyTorch <https://github.com/pytorch/pytorch>`_: an open-source machine
   learning library
 
-* `quasardb <https://www.quasardb.net/>`_: A distributed, high-performance,
+* `quasardb <https://www.quasardb.net/>`_: a distributed, high-performance,
   associative database
+  
+* `Quill <https://github.com/odygrd/quill>`_: asynchronous low-latency logging library
 
-* `readpe <https://bitbucket.org/sys_dev/readpe>`_: Read Portable Executable
+* `QKW <https://github.com/ravijanjam/qkw>`_: generalizing aliasing to simplify
+  navigation, and executing complex multi-line terminal command sequences
 
-* `redis-cerberus <https://github.com/HunanTV/redis-cerberus>`_: A Redis cluster
+* `redis-cerberus <https://github.com/HunanTV/redis-cerberus>`_: a Redis cluster
   proxy
 
-* `redpanda <https://vectorized.io/redpanda>`_: A 10x faster Kafka® replacement
-  for mission critical systems written in C++
+* `redpanda <https://vectorized.io/redpanda>`_: a 10x faster Kafka® replacement
+  for mission-critical systems written in C++
 
-* `rpclib <http://rpclib.net/>`_: A modern C++ msgpack-RPC server and client
+* `rpclib <http://rpclib.net/>`_: a modern C++ msgpack-RPC server and client
   library
 
 * `Salesforce Analytics Cloud
   <https://www.salesforce.com/analytics-cloud/overview/>`_:
-  Business intelligence software
+  business intelligence software
 
-* `Scylla <https://www.scylladb.com/>`_: A Cassandra-compatible NoSQL data store
+* `Scylla <https://www.scylladb.com/>`_: a Cassandra-compatible NoSQL data store
   that can handle 1 million transactions per second on a single server
 
-* `Seastar <http://www.seastar-project.org/>`_: An advanced, open-source C++
+* `Seastar <http://www.seastar-project.org/>`_: an advanced, open-source C++
   framework for high-performance server applications on modern hardware
 
-* `spdlog <https://github.com/gabime/spdlog>`_: Super fast C++ logging library
+* `spdlog <https://github.com/gabime/spdlog>`_: super fast C++ logging library
 
-* `Stellar <https://www.stellar.org/>`_: Financial platform
+* `Stellar <https://www.stellar.org/>`_: financial platform
 
-* `Touch Surgery <https://www.touchsurgery.com/>`_: Surgery simulator
+* `Touch Surgery <https://www.touchsurgery.com/>`_: surgery simulator
 
-* `TrinityCore <https://github.com/TrinityCore/TrinityCore>`_: Open-source
+* `TrinityCore <https://github.com/TrinityCore/TrinityCore>`_: open-source
   MMORPG framework
 
-* `Windows Terminal <https://github.com/microsoft/terminal>`_: The new Windows
-  Terminal
+* `🐙 userver framework <https://userver.tech/>`_: open-source asynchronous
+  framework with a rich set of abstractions and database drivers
+
+* `Windows Terminal <https://github.com/microsoft/terminal>`_: the new Windows
+  terminal
 
 `More... <https://github.com/search?q=fmtlib&type=Code>`_
 
@@ -433,16 +485,16 @@ error handling is awkward.
 Boost Format
 ~~~~~~~~~~~~
 
-This is a very powerful library which supports both ``printf``-like format
+This is a very powerful library that supports both ``printf``-like format
 strings and positional arguments. Its main drawback is performance. According to
-various benchmarks it is much slower than other methods considered here. Boost
+various benchmarks, it is much slower than other methods considered here. Boost
 Format also has excessive build times and severe code bloat issues (see
 `Benchmarks`_).
 
 FastFormat
 ~~~~~~~~~~
 
-This is an interesting library which is fast, safe and has positional arguments.
+This is an interesting library that is fast, safe, and has positional arguments.
 However, it has significant limitations, citing its author:
 
     Three features that have no hope of being accommodated within the
@@ -458,7 +510,7 @@ restrictive for using it in some projects.
 Boost Spirit.Karma
 ~~~~~~~~~~~~~~~~~~
 
-This is not really a formatting library but I decided to include it here for
+This is not a formatting library but I decided to include it here for
 completeness. As iostreams, it suffers from the problem of mixing verbatim text
 with arguments. The library is pretty fast, but slower on integer formatting
 than ``fmt::format_to`` with format string compilation on Karma's own benchmark,
@@ -477,7 +529,7 @@ Documentation License
 The `Format String Syntax <https://fmt.dev/latest/syntax.html>`_
 section in the documentation is based on the one from Python `string module
 documentation <https://docs.python.org/3/library/string.html#module-string>`_.
-For this reason the documentation is distributed under the Python Software
+For this reason, the documentation is distributed under the Python Software
 Foundation license available in `doc/python-license.txt
 <https://raw.github.com/fmtlib/fmt/master/doc/python-license.txt>`_.
 It only applies if you distribute the documentation of {fmt}.
@@ -486,8 +538,7 @@ Maintainers
 -----------
 
 The {fmt} library is maintained by Victor Zverovich (`vitaut
-<https://github.com/vitaut>`_) and Jonathan Müller (`foonathan
-<https://github.com/foonathan>`_) with contributions from many other people.
+<https://github.com/vitaut>`_) with contributions from many other people.
 See `Contributors <https://github.com/fmtlib/fmt/graphs/contributors>`_ and
 `Releases <https://github.com/fmtlib/fmt/releases>`_ for some of the names.
 Let us know if your contribution is not listed or mentioned incorrectly and

doc/CMakeLists.txt

@@ -1,13 +1,26 @@
-find_program(DOXYGEN doxygen)
+find_program(DOXYGEN doxygen
+  PATHS "$ENV{ProgramFiles}/doxygen/bin"
+        "$ENV{ProgramFiles\(x86\)}/doxygen/bin")
 if (NOT DOXYGEN)
   message(STATUS "Target 'doc' disabled (requires doxygen)")
   return ()
 endif ()
 
+# Find the Python interpreter and set the PYTHON_EXECUTABLE variable.
+if (CMAKE_VERSION VERSION_LESS 3.12)
+  # This logic is deprecated in CMake after 3.12.
+  find_package(PythonInterp QUIET REQUIRED)
+else ()
+  find_package(Python QUIET REQUIRED)
+  set(PYTHON_EXECUTABLE ${Python_EXECUTABLE})
+endif ()
+
 add_custom_target(doc
-  COMMAND ${CMAKE_CURRENT_SOURCE_DIR}/build.py ${FMT_VERSION}
+  COMMAND ${PYTHON_EXECUTABLE} ${CMAKE_CURRENT_SOURCE_DIR}/build.py
+                               ${FMT_VERSION}
   SOURCES api.rst syntax.rst usage.rst build.py conf.py _templates/layout.html)
 
+include(GNUInstallDirs)
 install(DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}/html/
-        DESTINATION share/doc/fmt OPTIONAL
+        DESTINATION ${CMAKE_INSTALL_DATAROOTDIR}/doc/fmt OPTIONAL
         PATTERN ".doctrees" EXCLUDE)

doc/api.rst

@@ -6,17 +6,20 @@ API Reference
 
 The {fmt} library API consists of the following parts:
 
-* :ref:`fmt/core.h <core-api>`: the core API providing argument handling
-  facilities and a lightweight subset of formatting functions
-* :ref:`fmt/format.h <format-api>`: the full format API providing compile-time
-  format string checks, wide string, output iterator and user-defined type
-  support
-* :ref:`fmt/ranges.h <ranges-api>`: additional formatting support for ranges
-  and tuples
+* :ref:`fmt/core.h <core-api>`: the core API providing main formatting functions
+  for ``char``/UTF-8 with C++20 compile-time checks and minimal dependencies
+* :ref:`fmt/format.h <format-api>`: the full format API providing additional
+  formatting functions and locale support
+* :ref:`fmt/ranges.h <ranges-api>`: formatting of ranges and tuples
 * :ref:`fmt/chrono.h <chrono-api>`: date and time formatting
+* :ref:`fmt/std.h <std-api>`: formatters for standard library types
 * :ref:`fmt/compile.h <compile-api>`: format string compilation
+* :ref:`fmt/color.h <color-api>`: terminal color and text style
+* :ref:`fmt/os.h <os-api>`: system APIs
 * :ref:`fmt/ostream.h <ostream-api>`: ``std::ostream`` support
+* :ref:`fmt/args.h <args-api>`: dynamic argument lists
 * :ref:`fmt/printf.h <printf-api>`: ``printf`` formatting
+* :ref:`fmt/xchar.h <xchar-api>`: optional ``wchar_t`` support 
 
 All functions and types provided by the library reside in namespace ``fmt`` and
 macros have prefix ``FMT_``.
@@ -26,118 +29,113 @@ macros have prefix ``FMT_``.
 Core API
 ========
 
-``fmt/core.h`` defines the core API which provides argument handling facilities
-and a lightweight subset of formatting functions. In the header-only mode
-include ``fmt/format.h`` instead of ``fmt/core.h``.
+``fmt/core.h`` defines the core API which provides main formatting functions
+for ``char``/UTF-8 with C++20 compile-time checks. It has minimal include
+dependencies for better compile times. This header is only beneficial when
+using {fmt} as a library (the default) and not in the header-only mode.
+It also provides ``formatter`` specializations for built-in and string types.
 
 The following functions use :ref:`format string syntax <syntax>`
 similar to that of Python's `str.format
-<http://docs.python.org/3/library/stdtypes.html#str.format>`_.
-They take *format_str* and *args* as arguments.
+<https://docs.python.org/3/library/stdtypes.html#str.format>`_.
+They take *fmt* and *args* as arguments.
 
-*format_str* is a format string that contains literal text and replacement
-fields surrounded by braces ``{}``. The fields are replaced with formatted
-arguments in the resulting string. A function taking *format_str* doesn't
-participate in an overload resolution if the latter is not a string.
+*fmt* is a format string that contains literal text and replacement fields
+surrounded by braces ``{}``. The fields are replaced with formatted arguments
+in the resulting string. `~fmt::format_string` is a format string which can be
+implicitly constructed from a string literal or a ``constexpr`` string and is
+checked at compile time in C++20. To pass a runtime format string wrap it in
+`fmt::runtime`.
 
 *args* is an argument list representing objects to be formatted.
 
 .. _format:
 
-.. doxygenfunction:: format(const S&, Args&&...)
-.. doxygenfunction:: vformat(const S&, basic_format_args<buffer_context<type_identity_t<Char>>>)
+.. doxygenfunction:: format(format_string<T...> fmt, T&&... args) -> std::string
+.. doxygenfunction:: vformat(string_view fmt, format_args args) -> std::string
+
+.. doxygenfunction:: format_to(OutputIt out, format_string<T...> fmt, T&&... args) -> OutputIt
+.. doxygenfunction:: format_to_n(OutputIt out, size_t n, format_string<T...> fmt, T&&... args) -> format_to_n_result<OutputIt>
+.. doxygenfunction:: formatted_size(format_string<T...> fmt, T&&... args) -> size_t
+
+.. doxygenstruct:: fmt::format_to_n_result
+   :members:
 
 .. _print:
 
-.. doxygenfunction:: print(const S&, Args&&...)
-.. doxygenfunction:: vprint(string_view, format_args)
+.. doxygenfunction:: fmt::print(format_string<T...> fmt, T&&... args)
+.. doxygenfunction:: fmt::vprint(string_view fmt, format_args args)
 
-.. doxygenfunction:: print(std::FILE *, const S&, Args&&...)
-.. doxygenfunction:: vprint(std::FILE *, string_view, format_args)
+.. doxygenfunction:: print(std::FILE *f, format_string<T...> fmt, T&&... args)
+.. doxygenfunction:: vprint(std::FILE *f, string_view fmt, format_args args)
 
-Named Arguments
----------------
-
-.. doxygenfunction:: fmt::arg(const S&, const T&)
-
-Named arguments are not supported in compile-time checks at the moment.
-
-Argument Lists
---------------
-
-.. doxygenfunction:: fmt::make_format_args(const Args&...)
-
-.. doxygenclass:: fmt::format_arg_store
-   :members:
-
-.. doxygenclass:: fmt::dynamic_format_arg_store
-   :members:
-
-.. doxygenclass:: fmt::basic_format_args
-   :members:
-
-.. doxygenstruct:: fmt::format_args
-
-.. doxygenclass:: fmt::basic_format_arg
-   :members:
-
-Compatibility
--------------
-
-.. doxygenclass:: fmt::basic_string_view
-   :members:
-
-.. doxygentypedef:: fmt::string_view
-.. doxygentypedef:: fmt::wstring_view
-
-Locale
-------
-
-All formatting is locale-independent by default. Use the ``'n'`` format
-specifier to insert the appropriate number separator characters from the
-locale::
-
-  #include <fmt/core.h>
-  #include <locale>
-
-  std::locale::global(std::locale("en_US.UTF-8"));
-  auto s = fmt::format("{:L}", 1000000);  // s == "1,000,000"
-
-.. _format-api:
-
-Format API
-==========
-
-``fmt/format.h`` defines the full format API providing compile-time format
-string checks, wide string, output iterator and user-defined type support.
-
-Compile-time Format String Checks
+Compile-Time Format String Checks
 ---------------------------------
 
-Compile-time checks are supported for built-in and string types as well as
-user-defined types with ``constexpr`` ``parse`` functions in their ``formatter``
-specializations.
+Compile-time format string checks are enabled by default on compilers
+that support C++20 ``consteval``. On older compilers you can use the
+:ref:`FMT_STRING <legacy-checks>`: macro defined in ``fmt/format.h`` instead.
 
-.. doxygendefine:: FMT_STRING
+Unused arguments are allowed as in Python's `str.format` and ordinary functions.
 
-Formatting User-defined Types
+.. doxygenclass:: fmt::basic_format_string
+   :members:
+
+.. doxygentypedef:: fmt::format_string
+
+.. doxygenfunction:: fmt::runtime(string_view) -> runtime_format_string<>
+
+.. _udt:
+
+Formatting User-Defined Types
 -----------------------------
 
-To make a user-defined type formattable, specialize the ``formatter<T>`` struct
-template and implement ``parse`` and ``format`` methods::
+The {fmt} library provides formatters for many standard C++ types.
+See :ref:`fmt/ranges.h <ranges-api>` for ranges and tuples including standard
+containers such as ``std::vector``, :ref:`fmt/chrono.h <chrono-api>` for date
+and time formatting and :ref:`fmt/std.h <std-api>` for other standard library
+types.
+
+There are two ways to make a user-defined type formattable: providing a
+``format_as`` function or specializing the ``formatter`` struct template.
+
+Use ``format_as`` if you want to make your type formattable as some other type
+with the same format specifiers. The ``format_as`` function should take an
+object of your type and return an object of a formattable type. It should be
+defined in the same namespace as your type.
+
+Example (https://godbolt.org/z/r7vvGE1v7)::
 
   #include <fmt/format.h>
 
-  struct point { double x, y; };
+  namespace kevin_namespacy {
+  enum class film {
+    house_of_cards, american_beauty, se7en = 7
+  };
+  auto format_as(film f) { return fmt::underlying(f); }
+  }
 
-  template <>
-  struct fmt::formatter<point> {
+  int main() {
+    fmt::print("{}\n", kevin_namespacy::film::se7en); // prints "7"
+  }
+
+Using the specialization API is more complex but gives you full control over
+parsing and formatting. To use this method specialize the ``formatter`` struct
+template for your type and implement ``parse`` and ``format`` methods.
+For example::
+
+  #include <fmt/core.h>
+
+  struct point {
+    double x, y;
+  };
+
+  template <> struct fmt::formatter<point> {
     // Presentation format: 'f' - fixed, 'e' - exponential.
     char presentation = 'f';
 
     // Parses format specifications of the form ['f' | 'e'].
-    constexpr auto parse(format_parse_context& ctx) {
-    // auto parse(format_parse_context &ctx) -> decltype(ctx.begin()) // c++11
+    constexpr auto parse(format_parse_context& ctx) -> format_parse_context::iterator {
       // [ctx.begin(), ctx.end()) is a character range that contains a part of
       // the format string starting from the format specifications to be parsed,
       // e.g. in
@@ -148,14 +146,17 @@ template and implement ``parse`` and ``format`` methods::
       // parse specifiers until '}' or the end of the range. In this example
       // the formatter should parse the 'f' specifier and return an iterator
       // pointing to '}'.
+      
+      // Please also note that this character range may be empty, in case of
+      // the "{}" format string, so therefore you should check ctx.begin()
+      // for equality with ctx.end().
 
       // Parse the presentation format and store it in the formatter:
       auto it = ctx.begin(), end = ctx.end();
       if (it != end && (*it == 'f' || *it == 'e')) presentation = *it++;
 
       // Check if reached the end of the range:
-      if (it != end && *it != '}')
-        throw format_error("invalid format");
+      if (it != end && *it != '}') throw_format_error("invalid format");
 
       // Return an iterator past the end of the parsed range:
       return it;
@@ -163,14 +164,11 @@ template and implement ``parse`` and ``format`` methods::
 
     // Formats the point p using the parsed format specification (presentation)
     // stored in this formatter.
-    template <typename FormatContext>
-    auto format(const point& p, FormatContext& ctx) {
-    // auto format(const point &p, FormatContext &ctx) -> decltype(ctx.out()) // c++11
+    auto format(const point& p, format_context& ctx) const -> format_context::iterator {
       // ctx.out() is an output iterator to write to.
-      return format_to(
-          ctx.out(),
-          presentation == 'f' ? "({:.1f}, {:.1f})" : "({:.1e}, {:.1e})",
-          p.x, p.y);
+      return presentation == 'f'
+                ? fmt::format_to(ctx.out(), "({:.1f}, {:.1f})", p.x, p.y)
+                : fmt::format_to(ctx.out(), "({:.1e}, {:.1e})", p.x, p.y);
     }
   };
 
@@ -183,22 +181,33 @@ Then you can pass objects of type ``point`` to any formatting function::
 You can also reuse existing formatters via inheritance or composition, for
 example::
 
+  // color.h:
+  #include <fmt/core.h>
+
   enum class color {red, green, blue};
 
   template <> struct fmt::formatter<color>: formatter<string_view> {
     // parse is inherited from formatter<string_view>.
-    template <typename FormatContext>
-    auto format(color c, FormatContext& ctx) {
-      string_view name = "unknown";
-      switch (c) {
-      case color::red:   name = "red"; break;
-      case color::green: name = "green"; break;
-      case color::blue:  name = "blue"; break;
-      }
-      return formatter<string_view>::format(name, ctx);
-    }
+
+    auto format(color c, format_context& ctx) const;
   };
 
+  // color.cc:
+  #include "color.h"
+  #include <fmt/format.h>
+
+  auto fmt::formatter<color>::format(color c, format_context& ctx) const {
+    string_view name = "unknown";
+    switch (c) {
+    case color::red:   name = "red"; break;
+    case color::green: name = "green"; break;
+    case color::blue:  name = "blue"; break;
+    }
+    return formatter<string_view>::format(name, ctx);
+  }
+
+Note that ``formatter<string_view>::format`` is defined in ``fmt/format.h`` so
+it has to be included in the source file.
 Since ``parse`` is inherited from ``formatter<string_view>`` it will recognize
 all string format specifications, for example
 
@@ -210,8 +219,9 @@ will return ``"      blue"``.
 
 You can also write a formatter for a hierarchy of classes::
 
+  // demo.h:
   #include <type_traits>
-  #include <fmt/format.h>
+  #include <fmt/core.h>
 
   struct A {
     virtual ~A() {}
@@ -225,56 +235,130 @@ You can also write a formatter for a hierarchy of classes::
   template <typename T>
   struct fmt::formatter<T, std::enable_if_t<std::is_base_of<A, T>::value, char>> :
       fmt::formatter<std::string> {
-    template <typename FormatCtx>
-    auto format(const A& a, FormatCtx& ctx) {
+    auto format(const A& a, format_context& ctx) const {
       return fmt::formatter<std::string>::format(a.name(), ctx);
     }
   };
 
+  // demo.cc:
+  #include "demo.h"
+  #include <fmt/format.h>
+
   int main() {
     B b;
     A& a = b;
     fmt::print("{}", a); // prints "B"
   }
 
+Providing both a ``formatter`` specialization and a ``format_as`` overload is
+disallowed.
+
+Named Arguments
+---------------
+
+.. doxygenfunction:: fmt::arg(const S&, const T&)
+
+Named arguments are not supported in compile-time checks at the moment.
+
+Argument Lists
+--------------
+
+You can create your own formatting function with compile-time checks and small
+binary footprint, for example (https://godbolt.org/z/vajfWEG4b):
+
+.. code:: c++
+
+    #include <fmt/core.h>
+
+    void vlog(const char* file, int line, fmt::string_view format,
+              fmt::format_args args) {
+      fmt::print("{}: {}: ", file, line);
+      fmt::vprint(format, args);
+    }
+
+    template <typename... T>
+    void log(const char* file, int line, fmt::format_string<T...> format, T&&... args) {
+      vlog(file, line, format, fmt::make_format_args(args...));
+    }
+
+    #define MY_LOG(format, ...) log(__FILE__, __LINE__, format, __VA_ARGS__)
+
+    MY_LOG("invalid squishiness: {}", 42);
+
+Note that ``vlog`` is not parameterized on argument types which improves compile
+times and reduces binary code size compared to a fully parameterized version.
+
+.. doxygenfunction:: fmt::make_format_args(const Args&...)
+
+.. doxygenclass:: fmt::format_arg_store
+   :members:
+
+.. doxygenclass:: fmt::basic_format_args
+   :members:
+
+.. doxygentypedef:: fmt::format_args
+
+.. doxygenclass:: fmt::basic_format_arg
+   :members:
+
 .. doxygenclass:: fmt::basic_format_parse_context
    :members:
 
-Output Iterator Support
------------------------
-
-.. doxygenfunction:: fmt::format_to(OutputIt, const S&, Args&&...)
-.. doxygenfunction:: fmt::format_to_n(OutputIt, size_t, const S&, const Args&...)
-.. doxygenstruct:: fmt::format_to_n_result
+.. doxygenclass:: fmt::basic_format_context
    :members:
 
-Literal-based API
+.. doxygentypedef:: fmt::format_context
+
+.. _args-api:
+
+Dynamic Argument Lists
+----------------------
+
+The header ``fmt/args.h`` provides ``dynamic_format_arg_store``, a builder-like
+API that can be used to construct format argument lists dynamically.
+
+.. doxygenclass:: fmt::dynamic_format_arg_store
+   :members:
+
+Compatibility
+-------------
+
+.. doxygenclass:: fmt::basic_string_view
+   :members:
+
+.. doxygentypedef:: fmt::string_view
+
+.. _format-api:
+
+Format API
+==========
+
+``fmt/format.h`` defines the full format API providing additional formatting
+functions and locale support.
+
+Literal-Based API
 -----------------
 
 The following user-defined literals are defined in ``fmt/format.h``.
 
-.. doxygenfunction:: operator""_format(const char *, size_t)
-
-.. doxygenfunction:: operator""_a(const char *, size_t)
+.. doxygenfunction:: operator""_a()
 
 Utilities
 ---------
 
-.. doxygenstruct:: fmt::is_char
+.. doxygenfunction:: fmt::ptr(T p) -> const void*
+.. doxygenfunction:: fmt::ptr(const std::unique_ptr<T, Deleter> &p) -> const void*
+.. doxygenfunction:: fmt::ptr(const std::shared_ptr<T> &p) -> const void*
 
-.. doxygentypedef:: fmt::char_t
+.. doxygenfunction:: fmt::underlying(Enum e) -> typename std::underlying_type<Enum>::type
 
-.. doxygenfunction:: fmt::formatted_size(string_view, const Args&...)
+.. doxygenfunction:: fmt::to_string(const T &value) -> std::string
 
-.. doxygenfunction:: fmt::to_string(const T&)
+.. doxygenfunction:: fmt::join(Range &&range, string_view sep) -> join_view<detail::iterator_t<Range>, detail::sentinel_t<Range>>
 
-.. doxygenfunction:: fmt::to_wstring(const T&)
+.. doxygenfunction:: fmt::join(It begin, Sentinel end, string_view sep) -> join_view<It, Sentinel>
 
-.. doxygenfunction:: fmt::to_string_view(const Char *)
-
-.. doxygenfunction:: fmt::join(const Range&, string_view)
-
-.. doxygenfunction:: fmt::join(It, Sentinel, string_view)
+.. doxygenfunction:: fmt::group_digits(T value) -> group_digits_view<T>
 
 .. doxygenclass:: fmt::detail::buffer
    :members:
@@ -286,20 +370,14 @@ Utilities
 System Errors
 -------------
 
-fmt does not use ``errno`` to communicate errors to the user, but it may call
-system functions which set ``errno``. Users should not make any assumptions about
-the value of ``errno`` being preserved by library functions.
+{fmt} does not use ``errno`` to communicate errors to the user, but it may call
+system functions which set ``errno``. Users should not make any assumptions
+about the value of ``errno`` being preserved by library functions.
 
-.. doxygenclass:: fmt::system_error
-   :members:
+.. doxygenfunction:: fmt::system_error
 
 .. doxygenfunction:: fmt::format_system_error
 
-.. doxygenclass:: fmt::windows_error
-   :members:
-
-.. _formatstrings:
-
 Custom Allocators
 -----------------
 
@@ -318,8 +396,8 @@ allocator::
 
     custom_string vformat(custom_allocator alloc, fmt::string_view format_str,
                           fmt::format_args args) {
-      custom_memory_buffer buf(alloc);
-      fmt::vformat_to(buf, format_str, args);
+      auto buf = custom_memory_buffer(alloc);
+      fmt::vformat_to(std::back_inserter(buf), format_str, args);
       return custom_string(buf.data(), buf.size(), alloc);
     }
 
@@ -330,15 +408,50 @@ allocator::
       return vformat(alloc, format_str, fmt::make_format_args(args...));
     }
 
-The allocator will be used for the output container only. If you are using named
-arguments, the container that stores pointers to them will be allocated using
-the default allocator. Also floating-point formatting falls back on ``sprintf``
-which may do allocations.
+The allocator will be used for the output container only. Formatting functions
+normally don't do any allocations for built-in and string types except for
+non-default floating-point formatting that occasionally falls back on
+``sprintf``.
+
+Locale
+------
+
+All formatting is locale-independent by default. Use the ``'L'`` format
+specifier to insert the appropriate number separator characters from the
+locale::
+
+  #include <fmt/core.h>
+  #include <locale>
+
+  std::locale::global(std::locale("en_US.UTF-8"));
+  auto s = fmt::format("{:L}", 1000000);  // s == "1,000,000"
+
+``fmt/format.h`` provides the following overloads of formatting functions that
+take ``std::locale`` as a parameter. The locale type is a template parameter to
+avoid the expensive ``<locale>`` include.
+
+.. doxygenfunction:: format(const Locale& loc, format_string<T...> fmt, T&&... args) -> std::string
+.. doxygenfunction:: format_to(OutputIt out, const Locale& loc, format_string<T...> fmt, T&&... args) -> OutputIt
+.. doxygenfunction:: formatted_size(const Locale& loc, format_string<T...> fmt, T&&... args) -> size_t
+
+.. _legacy-checks:
+
+Legacy Compile-Time Format String Checks
+----------------------------------------
+
+``FMT_STRING`` enables compile-time checks on older compilers. It requires C++14
+or later and is a no-op in C++11.
+
+.. doxygendefine:: FMT_STRING
+
+To force the use of legacy compile-time checks, define the preprocessor variable
+``FMT_ENFORCE_COMPILE_STRING``. When set, functions accepting ``FMT_STRING``
+will fail to compile with regular strings.
 
 .. _ranges-api:
 
-Ranges and Tuple Formatting
-===========================
+Range and Tuple Formatting
+==========================
 
 The library also supports convenient formatting of ranges and tuples::
 
@@ -365,58 +478,150 @@ Using ``fmt::join``, you can separate tuple elements with a custom separator::
 Date and Time Formatting
 ========================
 
-The library supports `strftime
-<http://en.cppreference.com/w/cpp/chrono/c/strftime>`_-like date and time
-formatting::
+``fmt/chrono.h`` provides formatters for
+
+* `std::chrono::duration <https://en.cppreference.com/w/cpp/chrono/duration>`_
+* `std::chrono::time_point
+  <https://en.cppreference.com/w/cpp/chrono/time_point>`_
+* `std::tm <https://en.cppreference.com/w/cpp/chrono/c/tm>`_
+
+The format syntax is described in :ref:`chrono-specs`.
+
+**Example**::
 
   #include <fmt/chrono.h>
 
-  std::time_t t = std::time(nullptr);
-  // Prints "The date is 2016-04-29." (with the current date)
-  fmt::print("The date is {:%Y-%m-%d}.", fmt::localtime(t));
+  int main() {
+    std::time_t t = std::time(nullptr);
 
-The format string syntax is described in the documentation of
-`strftime <http://en.cppreference.com/w/cpp/chrono/c/strftime>`_.
+    // Prints "The date is 2020-11-07." (with the current date):
+    fmt::print("The date is {:%Y-%m-%d}.", fmt::localtime(t));
+
+    using namespace std::literals::chrono_literals;
+
+    // Prints "Default format: 42s 100ms":
+    fmt::print("Default format: {} {}\n", 42s, 100ms);
+
+    // Prints "strftime-like format: 03:15:30":
+    fmt::print("strftime-like format: {:%H:%M:%S}\n", 3h + 15min + 30s);
+  }
+
+.. doxygenfunction:: localtime(std::time_t time)
+
+.. doxygenfunction:: gmtime(std::time_t time)
+
+.. _std-api:
+
+Standard Library Types Formatting
+=================================
+
+``fmt/std.h`` provides formatters for:
+
+* `std::filesystem::path <https://en.cppreference.com/w/cpp/filesystem/path>`_
+* `std::thread::id <https://en.cppreference.com/w/cpp/thread/thread/id>`_
+* `std::monostate <https://en.cppreference.com/w/cpp/utility/variant/monostate>`_
+* `std::variant <https://en.cppreference.com/w/cpp/utility/variant/variant>`_
+* `std::optional <https://en.cppreference.com/w/cpp/utility/optional>`_
+
+Formatting Variants
+-------------------
+
+A ``std::variant`` is only formattable if every variant alternative is formattable, and requires the
+``__cpp_lib_variant`` `library feature <https://en.cppreference.com/w/cpp/feature_test>`_.
+  
+**Example**::
+
+  #include <fmt/std.h>
+
+  std::variant<char, float> v0{'x'};
+  // Prints "variant('x')"
+  fmt::print("{}", v0);
+
+  std::variant<std::monostate, char> v1;
+  // Prints "variant(monostate)"
 
 .. _compile-api:
 
-Format string compilation
+Format String Compilation
 =========================
 
-``fmt/compile.h`` provides format string compilation support. Format strings
-are parsed at compile time and converted into efficient formatting code. This
-supports arguments of built-in and string types as well as user-defined types
-with ``constexpr`` ``parse`` functions in their ``formatter`` specializations.
+``fmt/compile.h`` provides format string compilation enabled via the
+``FMT_COMPILE`` macro or the ``_cf`` user-defined literal. Format strings
+marked with ``FMT_COMPILE`` or ``_cf`` are parsed, checked and converted into
+efficient formatting code at compile-time. This supports arguments of built-in
+and string types as well as user-defined types with ``format`` functions taking
+the format context type as a template parameter in their ``formatter``
+specializations. For example::
+
+  template <> struct fmt::formatter<point> {
+    constexpr auto parse(format_parse_context& ctx);
+
+    template <typename FormatContext>
+    auto format(const point& p, FormatContext& ctx) const;
+  };
+
 Format string compilation can generate more binary code compared to the default
 API and is only recommended in places where formatting is a performance
 bottleneck.
 
 .. doxygendefine:: FMT_COMPILE
 
+.. doxygenfunction:: operator""_cf()
+
+.. _color-api:
+
+Terminal Color and Text Style
+=============================
+
+``fmt/color.h`` provides support for terminal color and text style output.
+
+.. doxygenfunction:: print(const text_style &ts, const S &format_str, const Args&... args)
+
+.. doxygenfunction:: fg(detail::color_type)
+
+.. doxygenfunction:: bg(detail::color_type)
+
+.. doxygenfunction:: styled(const T& value, text_style ts)
+
+.. _os-api:
+
+System APIs
+===========
+
+.. doxygenclass:: fmt::ostream
+   :members:
+
+.. doxygenfunction:: fmt::windows_error
+   :members:
+
 .. _ostream-api:
 
 ``std::ostream`` Support
 ========================
 
 ``fmt/ostream.h`` provides ``std::ostream`` support including formatting of
-user-defined types that have overloaded ``operator<<``::
+user-defined types that have an overloaded insertion operator (``operator<<``).
+In order to make a type formattable via ``std::ostream`` you should provide a
+``formatter`` specialization inherited from ``ostream_formatter``::
 
   #include <fmt/ostream.h>
 
-  class date {
-    int year_, month_, day_;
-  public:
-    date(int year, int month, int day): year_(year), month_(month), day_(day) {}
+  struct date {
+    int year, month, day;
 
     friend std::ostream& operator<<(std::ostream& os, const date& d) {
-      return os << d.year_ << '-' << d.month_ << '-' << d.day_;
+      return os << d.year << '-' << d.month << '-' << d.day;
     }
   };
 
-  std::string s = fmt::format("The date is {}", date(2012, 12, 9));
+  template <> struct fmt::formatter<date> : ostream_formatter {};
+
+  std::string s = fmt::format("The date is {}", date{2012, 12, 9});
   // s == "The date is 2012-12-9"
 
-.. doxygenfunction:: print(std::basic_ostream<Char>&, const S&, Args&&...)
+.. doxygenfunction:: streamed(const T &)
+
+.. doxygenfunction:: print(std::ostream &os, format_string<T...> fmt, T&&... args)
 
 .. _printf-api:
 
@@ -425,18 +630,32 @@ user-defined types that have overloaded ``operator<<``::
 
 The header ``fmt/printf.h`` provides ``printf``-like formatting functionality.
 The following functions use `printf format string syntax
-<http://pubs.opengroup.org/onlinepubs/009695399/functions/fprintf.html>`_ with
+<https://pubs.opengroup.org/onlinepubs/009695399/functions/fprintf.html>`_ with
 the POSIX extension for positional arguments. Unlike their standard
 counterparts, the ``fmt`` functions are type-safe and throw an exception if an
 argument type doesn't match its format specification.
 
-.. doxygenfunction:: printf(const S&, const Args&...)
+.. doxygenfunction:: printf(string_view fmt, const T&... args) -> int
 
-.. doxygenfunction:: fprintf(std::FILE *, const S&, const Args&...)
+.. doxygenfunction:: fprintf(std::FILE *f, const S &fmt, const T&... args) -> int
 
-.. doxygenfunction:: fprintf(std::basic_ostream<Char>&, const S&, const Args&...)
+.. doxygenfunction:: sprintf(const S&, const T&...)
 
-.. doxygenfunction:: sprintf(const S&, const Args&...)
+.. _xchar-api:
+
+``wchar_t`` Support
+===================
+
+The optional header ``fmt/xchar.h`` provides support for ``wchar_t`` and exotic
+character types.
+
+.. doxygenstruct:: fmt::is_char
+
+.. doxygentypedef:: fmt::wstring_view
+
+.. doxygentypedef:: fmt::wformat_context
+
+.. doxygenfunction:: fmt::to_wstring(const T &value)
 
 Compatibility with C++20 ``std::format``
 ========================================
@@ -447,9 +666,6 @@ differences:
 
 * Names are defined in the ``fmt`` namespace instead of ``std`` to avoid
   collisions with standard library implementations.
-* The ``'L'`` format specifier cannot be combined with presentation specifiers
-  yet.
 * Width calculation doesn't use grapheme clusterization. The latter has been
   implemented in a separate branch but hasn't been integrated yet.
-* Chrono formatting doesn't support C++20 date types since they are not provided
-  by standard library implementations.
+* Most C++20 chrono types are not supported yet.

doc/basic-bootstrap/layout.html

@@ -90,12 +90,14 @@
         VERSION:     '{{ release|e }}',
         COLLAPSE_INDEX: false,
         FILE_SUFFIX: '{{ '' if no_search_suffix else file_suffix }}',
+        LINK_SUFFIX: '{{ link_suffix }}',
+        SOURCELINK_SUFFIX: '{{ sourcelink_suffix }}',
         HAS_SOURCE:  {{ has_source|lower }},
         SOURCELINK_SUFFIX:  '{{ sourcelink_suffix }}'
       };
     </script>
     {%- for scriptfile in script_files %}
-    <script type="text/javascript" src="{{ pathto(scriptfile, 1) }}"></script>
+    {{ js_tag(scriptfile) }}
     {%- endfor %}
 {%- endmacro %}
 

doc/build.py

@@ -1,63 +1,38 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 # Build the documentation.
 
-from __future__ import print_function
-import errno, os, shutil, sys, tempfile
-from subprocess import check_call, check_output, CalledProcessError, Popen, PIPE
-from distutils.version import LooseVersion
+import errno, os, re, sys
+from subprocess import check_call, CalledProcessError, Popen, PIPE, STDOUT
 
-versions = ['1.0.0', '1.1.0', '2.0.0', '3.0.2', '4.0.0', '4.1.0', '5.0.0', '5.1.0', '5.2.0', '5.2.1', '5.3.0', '6.0.0', '6.1.0', '6.1.1', '6.1.2', '6.2.0', '6.2.1', '7.0.0', '7.0.1', '7.0.2', '7.0.3']
+versions = ['1.0.0', '1.1.0', '2.0.0', '3.0.2', '4.0.0', '4.1.0', '5.0.0', '5.1.0', '5.2.0', '5.2.1', '5.3.0', '6.0.0', '6.1.0', '6.1.1', '6.1.2', '6.2.0', '6.2.1', '7.0.0', '7.0.1', '7.0.2', '7.0.3', '7.1.0', '7.1.1', '7.1.2', '7.1.3', '8.0.0', '8.0.1', '8.1.0', '8.1.1', '9.0.0', '9.1.0', '10.0.0', '10.1.0', '10.1.1']
 
-def pip_install(package, commit=None, **kwargs):
-  "Install package using pip."
-  min_version = kwargs.get('min_version')
-  if min_version:
-    from pkg_resources import get_distribution, DistributionNotFound
-    try:
-      installed_version = get_distribution(os.path.basename(package)).version
-      if LooseVersion(installed_version) >= min_version:
-        print('{} {} already installed'.format(package, min_version))
-        return
-    except DistributionNotFound:
-      pass
-  if commit:
-    package = 'git+https://github.com/{0}.git@{1}'.format(package, commit)
-  print('Installing {0}'.format(package))
-  check_call(['pip', 'install', package])
+class Pip:
+  def __init__(self, venv_dir):
+    self.path = os.path.join(venv_dir, 'bin', 'pip')
 
-def create_build_env(dirname='virtualenv'):
+  def install(self, package, commit=None):
+    "Install package using pip."
+    if commit:
+      package = 'git+https://github.com/{0}.git@{1}'.format(package, commit)
+    print('Installing {0}'.format(package))
+    check_call([self.path, 'install', package])
+
+def create_build_env(venv_dir='virtualenv'):
   # Create virtualenv.
-  if not os.path.exists(dirname):
-    check_call(['virtualenv', dirname])
-  import sysconfig
-  scripts_dir = os.path.basename(sysconfig.get_path('scripts'))
-  activate_this_file = os.path.join(dirname, scripts_dir, 'activate_this.py')
-  with open(activate_this_file) as f:
-    exec(f.read(), dict(__file__=activate_this_file))
-  # Import get_distribution after activating virtualenv to get info about
-  # the correct packages.
-  from pkg_resources import get_distribution, DistributionNotFound
-  # Upgrade pip because installation of sphinx with pip 1.1 available on Travis
-  # is broken (see #207) and it doesn't support the show command.
-  pip_version = get_distribution('pip').version
-  if LooseVersion(pip_version) < LooseVersion('1.5.4'):
-    print("Updating pip")
-    check_call(['pip', 'install', '--upgrade', 'pip'])
-  # Upgrade distribute because installation of sphinx with distribute 0.6.24
-  # available on Travis is broken (see #207).
-  try:
-    distribute_version = get_distribution('distribute').version
-    if LooseVersion(distribute_version) <= LooseVersion('0.6.24'):
-      print("Updating distribute")
-      check_call(['pip', 'install', '--upgrade', 'distribute'])
-  except DistributionNotFound:
-    pass
-  # Install Sphinx and Breathe.
-  pip_install('sphinx-doc/sphinx', '12b83372ac9316e8cbe86e7fed889296a4cc29ee',
-              min_version='1.4.1.dev20160531')
-  pip_install('michaeljones/breathe',
-              '129222318f7c8f865d2631e7da7b033567e7f56a',
-              min_version='4.2.0')
+  if not os.path.exists(venv_dir):
+    check_call(['python3', '-m', 'venv', venv_dir])
+  # Install Sphinx and Breathe. Require the exact version of Sphinx which is
+  # compatible with Breathe.
+  pip = Pip(venv_dir)
+  pip.install('wheel')
+  pip.install('six')
+  # See: https://github.com/sphinx-doc/sphinx/issues/9777
+  pip.install('docutils==0.17.1')
+  # Jinja2 >= 3.1 incompatible with sphinx 3.3.0
+  # See: https://github.com/sphinx-doc/sphinx/issues/10291
+  pip.install('Jinja2<3.1')
+  pip.install('sphinx-doc/sphinx', 'v3.3.0')
+  pip.install('michaeljones/breathe', 'v4.25.0')
 
 def build_docs(version='dev', **kwargs):
   doc_dir = kwargs.get('doc_dir', os.path.dirname(os.path.realpath(__file__)))
@@ -66,16 +41,17 @@ def build_docs(version='dev', **kwargs):
       'include_dir', os.path.join(os.path.dirname(doc_dir), 'include', 'fmt'))
   # Build docs.
   cmd = ['doxygen', '-']
-  p = Popen(cmd, stdin=PIPE)
+  p = Popen(cmd, stdin=PIPE, stdout=PIPE, stderr=STDOUT)
   doxyxml_dir = os.path.join(work_dir, 'doxyxml')
-  p.communicate(input=r'''
+  out, _ = p.communicate(input=r'''
       PROJECT_NAME      = fmt
       GENERATE_LATEX    = NO
       GENERATE_MAN      = NO
       GENERATE_RTF      = NO
       CASE_SENSE_NAMES  = NO
-      INPUT             = {0}/core.h {0}/compile.h {0}/format.h {0}/os.h \
-                          {0}/ostream.h {0}/printf.h {0}/time.h
+      INPUT             = {0}/args.h {0}/chrono.h {0}/color.h {0}/core.h \
+                          {0}/compile.h  {0}/format.h {0}/os.h {0}/ostream.h \
+                          {0}/printf.h {0}/xchar.h
       QUIET             = YES
       JAVADOC_AUTOBRIEF = YES
       AUTOLINK_SUPPORT  = NO
@@ -86,28 +62,49 @@ def build_docs(version='dev', **kwargs):
       ALIASES          += "endrst=\endverbatim"
       MACRO_EXPANSION   = YES
       PREDEFINED        = _WIN32=1 \
+                          __linux__=1 \
+                          FMT_ENABLE_IF(...)= \
                           FMT_USE_VARIADIC_TEMPLATES=1 \
                           FMT_USE_RVALUE_REFERENCES=1 \
                           FMT_USE_USER_DEFINED_LITERALS=1 \
                           FMT_USE_ALIAS_TEMPLATES=1 \
+                          FMT_USE_NONTYPE_TEMPLATE_ARGS=1 \
                           FMT_API= \
                           "FMT_BEGIN_NAMESPACE=namespace fmt {{" \
                           "FMT_END_NAMESPACE=}}" \
                           "FMT_STRING_ALIAS=1" \
-                          "FMT_ENABLE_IF(B)="
-      EXCLUDE_SYMBOLS   = fmt::internal::* StringValue write_str
+                          "FMT_VARIADIC(...)=" \
+                          "FMT_VARIADIC_W(...)=" \
+                          "FMT_DOC=1"
+      EXCLUDE_SYMBOLS   = fmt::formatter fmt::printf_formatter fmt::arg_join \
+                          fmt::basic_format_arg::handle
     '''.format(include_dir, doxyxml_dir).encode('UTF-8'))
+  out = out.decode('utf-8')
+  internal_symbols = [
+    'fmt::detail::.*',
+    'basic_data<>',
+    'fmt::type_identity'
+  ]
+  noisy_warnings = [
+    'warning: (Compound|Member .* of class) (' + '|'.join(internal_symbols) + \
+      ') is not documented.',
+    'warning: Internal inconsistency: .* does not belong to any container!'
+  ]
+  for w in noisy_warnings:
+      out = re.sub('.*' + w + '\n', '', out)
+  print(out)
   if p.returncode != 0:
     raise CalledProcessError(p.returncode, cmd)
+
   html_dir = os.path.join(work_dir, 'html')
   main_versions = reversed(versions[-3:])
-  check_call(['sphinx-build',
+  check_call([os.path.join(work_dir, 'virtualenv', 'bin', 'sphinx-build'),
               '-Dbreathe_projects.format=' + os.path.abspath(doxyxml_dir),
               '-Dversion=' + version, '-Drelease=' + version,
               '-Aversion=' + version, '-Aversions=' + ','.join(main_versions),
               '-b', 'html', doc_dir, html_dir])
   try:
-    check_call(['lessc', '--clean-css',
+    check_call(['lessc', '--verbose', '--clean-css',
                 '--include-path=' + os.path.join(doc_dir, 'bootstrap'),
                 os.path.join(doc_dir, 'fmt.less'),
                 os.path.join(html_dir, '_static', 'fmt.css')])

doc/fmt.less

@@ -56,6 +56,11 @@ div.sphinxsidebar {
   padding: 0;
 }
 
+// Override center alignment in tables.
+td {
+  text-align: left;
+}
+
 p.rubric {
   margin-top: 10px;
 }

doc/index.rst

@@ -23,24 +23,26 @@ Format API
 
 The format API is similar in spirit to the C ``printf`` family of function but
 is safer, simpler and several times `faster
-<http://zverovich.net/2013/09/07/integer-to-string-conversion-in-cplusplus.html>`_
+<https://www.zverovich.net/2020/06/13/fast-int-to-string-revisited.html>`_
 than common standard library implementations.
 The `format string syntax <syntax.html>`_ is similar to the one used by
-`str.format <http://docs.python.org/3/library/stdtypes.html#str.format>`_ in
+`str.format <https://docs.python.org/3/library/stdtypes.html#str.format>`_ in
 Python:
 
 .. code:: c++
 
-  fmt::format("The answer is {}.", 42);
+  std::string s = fmt::format("The answer is {}.", 42);
   
 The ``fmt::format`` function returns a string "The answer is 42.". You can use
 ``fmt::memory_buffer`` to avoid constructing ``std::string``:
 
 .. code:: c++
 
-  fmt::memory_buffer out;
-  format_to(out, "For a moment, {} happened.", "nothing");
-  out.data(); // returns a pointer to the formatted data
+  auto out = fmt::memory_buffer();
+  fmt::format_to(std::back_inserter(out),
+            "For a moment, {} happened.", "nothing");
+  auto data = out.data(); // pointer to the formatted data
+  auto size = out.size(); // size of the formatted data
 
 The ``fmt::print`` function performs formatting and writes the result to a stream:
 
@@ -48,21 +50,19 @@ The ``fmt::print`` function performs formatting and writes the result to a strea
 
   fmt::print(stderr, "System error code = {}\n", errno);
 
-The file argument can be omitted in which case the function prints to
-``stdout``:
+If you omit the file argument the function will print to ``stdout``:
 
 .. code:: c++
 
   fmt::print("Don't {}\n", "panic");
 
-The Format API also supports positional arguments useful for localization:
+The format API also supports positional arguments useful for localization:
 
 .. code:: c++
 
   fmt::print("I'd rather be {1} than {0}.", "right", "happy");
 
-Named arguments can be created with ``fmt::arg``. This makes it easier to track 
-what goes where when multiple arguments are being formatted:
+You can pass named arguments with ``fmt::arg``:
 
 .. code:: c++
 
@@ -91,16 +91,17 @@ time. For example, the code
 
   fmt::format("The answer is {:d}", "forty-two");
 
-throws a ``format_error`` exception with description "unknown format code 'd' for
-string", because the argument ``"forty-two"`` is a string while the format code
-``d`` only applies to integers, while
+throws the ``format_error`` exception because the argument ``"forty-two"`` is a
+string while the format code ``d`` only applies to integers.
+
+The code
 
 .. code:: c++
 
   format(FMT_STRING("The answer is {:d}"), "forty-two");
 
-reports a compile-time error for the same reason on compilers that support
-relaxed ``constexpr``. See `here <api.html#c.fmt>`_ for details.
+reports a compile-time error on compilers that support relaxed ``constexpr``.
+See `here <api.html#compile-time-format-string-checks>`_ for details.
 
 The following code
 
@@ -109,21 +110,15 @@ The following code
   fmt::format("Cyrillic letter {}", L'\x42e');
   
 produces a compile-time error because wide character ``L'\x42e'`` cannot be
-formatted into a narrow string. You can use a wide format string instead:
-
-.. code:: c++
-
-  fmt::format(L"Cyrillic letter {}", L'\x42e');
-
-For comparison, writing a wide character to ``std::ostream`` results in
-its numeric value being written to the stream (i.e. 1070 instead of letter 'ю'
-which is represented by ``L'\x42e'`` if we use Unicode) which is rarely what is
-needed.
+formatted into a narrow string. For comparison, writing a wide character to
+``std::ostream`` results in its numeric value being written to the stream
+(i.e. 1070 instead of letter 'ю' which is represented by ``L'\x42e'`` if we
+use Unicode) which is rarely desirable.
 
 Compact Binary Code
 -------------------
 
-The library is designed to produce compact per-call compiled code. For example
+The library produces compact per-call compiled code. For example
 (`godbolt <https://godbolt.org/g/TZU4KF>`_),
 
 .. code:: c++
@@ -144,8 +139,8 @@ compiles to just
      mov rcx, rsp
      mov edi, offset .L.str
      mov esi, 17
-     mov edx, 2
-     call fmt::v5::vprint(fmt::v5::basic_string_view<char>, fmt::v5::format_args)
+     mov edx, 1
+     call fmt::v7::vprint(fmt::v7::basic_string_view<char>, fmt::v7::format_args)
      xor eax, eax
      add rsp, 24
      ret
@@ -167,20 +162,19 @@ The library is highly portable and relies only on a small set of C++11 features:
 * deleted functions
 * alias templates
 
-These are available since GCC 4.8, Clang 3.0 and MSVC 19.0 (2015). For older
-compilers use {fmt} `version 4.x
-<https://github.com/fmtlib/fmt/releases/tag/4.1.0>`_ which continues to be
-maintained and only requires C++98.
+These are available in GCC 4.8, Clang 3.4, MSVC 19.0 (2015) and more recent
+compiler version. For older compilers use {fmt} `version 4.x
+<https://github.com/fmtlib/fmt/releases/tag/4.1.0>`_ which is maintained and
+only requires C++98.
 
-The output of all formatting functions is consistent across platforms. In
-particular, formatting a floating-point infinity always gives ``inf`` while the
-output of ``printf`` is platform-dependent. For example,
+The output of all formatting functions is consistent across platforms.
+For example,
 
 .. code::
 
   fmt::print("{}", std::numeric_limits<double>::infinity());
 
-always prints ``inf``.
+always prints ``inf`` while the output of ``printf`` is platform-dependent.
 
 .. _ease-of-use:
 
@@ -192,11 +186,13 @@ just three header files and no external dependencies.
 A permissive MIT `license <https://github.com/fmtlib/fmt#license>`_ allows
 using the library both in open-source and commercial projects.
 
+`Learn more... <contents.html>`_
+
 .. raw:: html
 
   <a class="btn btn-success" href="https://github.com/fmtlib/fmt">GitHub Repository</a>
 
   <div class="section footer">
-    <iframe src="http://ghbtns.com/github-btn.html?user=fmtlib&amp;repo=fmt&amp;type=watch&amp;count=true"
+    <iframe src="https://ghbtns.com/github-btn.html?user=fmtlib&amp;repo=fmt&amp;type=watch&amp;count=true"
             class="github-btn" width="100" height="20"></iframe>
   </div>

doc/syntax.rst

@@ -16,7 +16,7 @@ literal text, it can be escaped by doubling: ``{{`` and ``}}``.
 The grammar for a replacement field is as follows:
 
 .. productionlist:: sf
-   replacement_field: "{" [`arg_id`] [":" `format_spec`] "}"
+   replacement_field: "{" [`arg_id`] [":" (`format_spec` | `chrono_format_spec`)] "}"
    arg_id: `integer` | `identifier`
    integer: `digit`+
    digit: "0"..."9"
@@ -27,8 +27,8 @@ The grammar for a replacement field is as follows:
 In less formal terms, the replacement field can start with an *arg_id*
 that specifies the argument whose value is to be formatted and inserted into
 the output instead of the replacement field.
-The *arg_id* is optionally followed by a *format_spec*, which is preceded
-by a colon ``':'``.  These specify a non-default format for the replacement value.
+The *arg_id* is optionally followed by a *format_spec*, which is preceded by a
+colon ``':'``.  These specify a non-default format for the replacement value.
 
 See also the :ref:`formatspec` section.
 
@@ -75,14 +75,14 @@ although some of the formatting options are only supported by the numeric types.
 The general form of a *standard format specifier* is:
 
 .. productionlist:: sf
-   format_spec: [[`fill`]`align`][`sign`]["#"]["0"][`width`]["." `precision`][`type`]
+   format_spec: [[`fill`]`align`][`sign`]["#"]["0"][`width`]["." `precision`]["L"][`type`]
    fill: <a character other than '{' or '}'>
    align: "<" | ">" | "^"
    sign: "+" | "-" | " "
    width: `integer` | "{" [`arg_id`] "}"
    precision: `integer` | "{" [`arg_id`] "}"
-   type: `int_type` | "a" | "A" | "c" | "e" | "E" | "f" | "F" | "g" | "G" | "L" | "p" | "s"
-   int_type: "b" | "B" | "d" | "o" | "x" | "X"
+   type: "a" | "A" | "b" | "B" | "c" | "d" | "e" | "E" | "f" | "F" | "g" | "G" |
+       : "o" | "p" | "s" | "x" | "X"
 
 The *fill* character can be any Unicode code point other than ``'{'`` or
 ``'}'``. The presence of a fill character is signaled by the character following
@@ -109,21 +109,21 @@ Note that unless a minimum field width is defined, the field width will always
 be the same size as the data to fill it, so that the alignment option has no
 meaning in this case.
 
-The *sign* option is only valid for number types, and can be one of the
-following:
+The *sign* option is only valid for floating point and signed integer types,
+and can be one of the following:
 
-+---------+----------------------------------------------------------+
-| Option  | Meaning                                                  |
-+=========+==========================================================+
-| ``'+'`` | indicates that a sign should be used for both            |
-|         | positive as well as negative numbers.                    |
-+---------+----------------------------------------------------------+
-| ``'-'`` | indicates that a sign should be used only for negative   |
-|         | numbers (this is the default behavior).                  |
-+---------+----------------------------------------------------------+
-| space   | indicates that a leading space should be used on         |
-|         | positive numbers, and a minus sign on negative numbers.  |
-+---------+----------------------------------------------------------+
++---------+------------------------------------------------------------+
+| Option  | Meaning                                                    |
++=========+============================================================+
+| ``'+'`` | indicates that a sign should be used for both              |
+|         | nonnegative as well as negative numbers.                   |
++---------+------------------------------------------------------------+
+| ``'-'`` | indicates that a sign should be used only for negative     |
+|         | numbers (this is the default behavior).                    |
++---------+------------------------------------------------------------+
+| space   | indicates that a leading space should be used on           |
+|         | nonnegative numbers, and a minus sign on negative numbers. |
++---------+------------------------------------------------------------+
 
 The ``'#'`` option causes the "alternate form" to be used for the
 conversion.  The alternate form is defined differently for different
@@ -161,7 +161,11 @@ displayed after the decimal point for a floating-point value formatted with
 value formatted with ``'g'`` or ``'G'``.  For non-number types the field
 indicates the maximum field size - in other words, how many characters will be
 used from the field content. The *precision* is not allowed for integer,
-character, Boolean, and pointer values.
+character, Boolean, and pointer values. Note that a C string must be
+null-terminated even if precision is specified.
+
+The ``'L'`` option uses the current locale setting to insert the appropriate
+number separator characters. This option is only valid for numeric types.
 
 Finally, the *type* determines how the data should be presented.
 
@@ -200,6 +204,8 @@ The available integer presentation types are:
 |         | ``'#'`` option with this type adds the prefix ``"0B"``   |
 |         | to the output value.                                     |
 +---------+----------------------------------------------------------+
+| ``'c'`` | Character format. Outputs the number as a character.     |
++---------+----------------------------------------------------------+
 | ``'d'`` | Decimal integer. Outputs the number in base 10.          |
 +---------+----------------------------------------------------------+
 | ``'o'`` | Octal format. Outputs the number in base 8.              |
@@ -214,10 +220,6 @@ The available integer presentation types are:
 |         | ``'#'`` option with this type adds the prefix ``"0X"``   |
 |         | to the output value.                                     |
 +---------+----------------------------------------------------------+
-| ``'L'`` | Locale-specific format. This is the same as ``'d'``,     |
-|         | except that it uses the current locale setting to insert |
-|         | the appropriate number separator characters.             |
-+---------+----------------------------------------------------------+
 | none    | The same as ``'d'``.                                     |
 +---------+----------------------------------------------------------+
 
@@ -261,14 +263,8 @@ The available presentation types for floating-point values are:
 |         | ``'E'`` if the number gets too large. The                |
 |         | representations of infinity and NaN are uppercased, too. |
 +---------+----------------------------------------------------------+
-| ``'L'`` | Locale-specific format. This is the same as ``'g'``,     |
-|         | except that it uses the current locale setting to insert |
-|         | the appropriate number separator characters.             |
-+---------+----------------------------------------------------------+
-| none    | Similar to ``'g'``, except that fixed-point notation,    |
-|         | when used, has at least one digit past the decimal       |
-|         | point. The default precision is as high as needed to     |
-|         | represent the particular value.                          |
+| none    | Similar to ``'g'``, except that the default precision is |
+|         | as high as needed to represent the particular value.     |
 +---------+----------------------------------------------------------+
 
 .. ifconfig:: False
@@ -303,6 +299,212 @@ The available presentation types for pointers are:
 | none    | The same as ``'p'``.                                     |
 +---------+----------------------------------------------------------+
 
+.. _chrono-specs:
+
+Chrono Format Specifications
+============================
+
+Format specifications for chrono duration and time point types as well as
+``std::tm`` have the following syntax:
+
+.. productionlist:: sf
+   chrono_format_spec: [[`fill`]`align`][`width`]["." `precision`][`chrono_specs`]
+   chrono_specs: [`chrono_specs`] `conversion_spec` | `chrono_specs` `literal_char`
+   conversion_spec: "%" [`modifier`] `chrono_type`
+   literal_char: <a character other than '{', '}' or '%'>
+   modifier: "E" | "O"
+   chrono_type: "a" | "A" | "b" | "B" | "c" | "C" | "d" | "D" | "e" | "F" |
+              : "g" | "G" | "h" | "H" | "I" | "j" | "m" | "M" | "n" | "p" |
+              : "q" | "Q" | "r" | "R" | "S" | "t" | "T" | "u" | "U" | "V" |
+              : "w" | "W" | "x" | "X" | "y" | "Y" | "z" | "Z" | "%"
+
+Literal chars are copied unchanged to the output. Precision is valid only for
+``std::chrono::duration`` types with a floating-point representation type.
+
+The available presentation types (*chrono_type*) are:
+
++---------+--------------------------------------------------------------------+
+| Type    | Meaning                                                            |
++=========+====================================================================+
+| ``'a'`` | The abbreviated weekday name, e.g. "Sat". If the value does not    |
+|         | contain a valid weekday, an exception of type ``format_error`` is  |
+|         | thrown.                                                            |
++---------+--------------------------------------------------------------------+
+| ``'A'`` | The full weekday name, e.g. "Saturday". If the value does not      |
+|         | contain a valid weekday, an exception of type ``format_error`` is  |
+|         | thrown.                                                            |
++---------+--------------------------------------------------------------------+
+| ``'b'`` | The abbreviated month name, e.g. "Nov". If the value does not      |
+|         | contain a valid month, an exception of type ``format_error`` is    |
+|         | thrown.                                                            |
++---------+--------------------------------------------------------------------+
+| ``'B'`` | The full month name, e.g. "November". If the value does not        |
+|         | contain a valid month, an exception of type ``format_error`` is    |
+|         | thrown.                                                            |
++---------+--------------------------------------------------------------------+
+| ``'c'`` | The date and time representation, e.g. "Sat Nov 12 22:04:00 1955". |
+|         | The modified command ``%Ec`` produces the locale's alternate date  |
+|         | and time representation.                                           |
++---------+--------------------------------------------------------------------+
+| ``'C'`` | The year divided by 100 using floored division, e.g. "55". If the  |
+|         | result is a single decimal digit, it is prefixed with 0.           |
+|         | The modified command ``%EC`` produces the locale's alternative     |
+|         | representation of the century.                                     |
++---------+--------------------------------------------------------------------+
+| ``'d'`` | The day of month as a decimal number. If the result is a single    |
+|         | decimal digit, it is prefixed with 0. The modified command ``%Od`` |
+|         | produces the locale's alternative representation.                  |
++---------+--------------------------------------------------------------------+
+| ``'D'`` | Equivalent to ``%m/%d/%y``, e.g. "11/12/55".                       |
++---------+--------------------------------------------------------------------+
+| ``'e'`` | The day of month as a decimal number. If the result is a single    |
+|         | decimal digit, it is prefixed with a space. The modified command   |
+|         | ``%Oe`` produces the locale's alternative representation.          |
++---------+--------------------------------------------------------------------+
+| ``'F'`` | Equivalent to ``%Y-%m-%d``, e.g. "1955-11-12".                     |
++---------+--------------------------------------------------------------------+
+| ``'g'`` | The last two decimal digits of the ISO week-based year. If the     |
+|         | result is a single digit it is prefixed by 0.                      |
++---------+--------------------------------------------------------------------+
+| ``'G'`` | The ISO week-based year as a decimal number. If the result is less |
+|         | than four digits it is left-padded with 0 to four digits.          |
++---------+--------------------------------------------------------------------+
+| ``'h'`` | Equivalent to ``%b``, e.g. "Nov".                                  |
++---------+--------------------------------------------------------------------+
+| ``'H'`` | The hour (24-hour clock) as a decimal number. If the result is a   |
+|         | single digit, it is prefixed with 0. The modified command ``%OH``  |
+|         | produces the locale's alternative representation.                  |
++---------+--------------------------------------------------------------------+
+| ``'I'`` | The hour (12-hour clock) as a decimal number. If the result is a   |
+|         | single digit, it is prefixed with 0. The modified command ``%OI``  |
+|         | produces the locale's alternative representation.                  |
++---------+--------------------------------------------------------------------+
+| ``'j'`` | If the type being formatted is a specialization of duration, the   |
+|         | decimal number of days without padding. Otherwise, the day of the  |
+|         | year as a decimal number. Jan 1 is 001. If the result is less than |
+|         | three digits, it is left-padded with 0 to three digits.            |
++---------+--------------------------------------------------------------------+
+| ``'m'`` | The month as a decimal number. Jan is 01. If the result is a       |
+|         | single digit, it is prefixed with 0. The modified command ``%Om``  |
+|         | produces the locale's alternative representation.                  |
++---------+--------------------------------------------------------------------+
+| ``'M'`` | The minute as a decimal number. If the result is a single digit,   |
+|         | it is prefixed with 0. The modified command ``%OM`` produces the   |
+|         | locale's alternative representation.                               |
++---------+--------------------------------------------------------------------+
+| ``'n'`` | A new-line character.                                              |
++---------+--------------------------------------------------------------------+
+| ``'p'`` | The AM/PM designations associated with a 12-hour clock.            |
++---------+--------------------------------------------------------------------+
+| ``'q'`` | The duration's unit suffix.                                        |
++---------+--------------------------------------------------------------------+
+| ``'Q'`` | The duration's numeric value (as if extracted via ``.count()``).   |
++---------+--------------------------------------------------------------------+
+| ``'r'`` | The 12-hour clock time, e.g. "10:04:00 PM".                        |
++---------+--------------------------------------------------------------------+
+| ``'R'`` | Equivalent to ``%H:%M``, e.g. "22:04".                             |
++---------+--------------------------------------------------------------------+
+| ``'S'`` | Seconds as a decimal number. If the number of seconds is less than |
+|         | 10, the result is prefixed with 0. If the precision of the input   |
+|         | cannot be exactly represented with seconds, then the format is a   |
+|         | decimal floating-point number with a fixed format and a precision  |
+|         | matching that of the precision of the input (or to a microseconds  |
+|         | precision if the conversion to floating-point decimal seconds      |
+|         | cannot be made within 18 fractional digits). The character for the |
+|         | decimal point is localized according to the locale. The modified   |
+|         | command ``%OS`` produces the locale's alternative representation.  |
++---------+--------------------------------------------------------------------+
+| ``'t'`` | A horizontal-tab character.                                        |
++---------+--------------------------------------------------------------------+
+| ``'T'`` | Equivalent to ``%H:%M:%S``.                                        |
++---------+--------------------------------------------------------------------+
+| ``'u'`` | The ISO weekday as a decimal number (1-7), where Monday is 1. The  |
+|         | modified command ``%Ou`` produces the locale's alternative         |
+|         | representation.                                                    |
++---------+--------------------------------------------------------------------+
+| ``'U'`` | The week number of the year as a decimal number. The first Sunday  |
+|         | of the year is the first day of week 01. Days of the same year     |
+|         | prior to that are in week 00. If the result is a single digit, it  |
+|         | is prefixed with 0. The modified command ``%OU`` produces the      |
+|         | locale's alternative representation.                               |
++---------+--------------------------------------------------------------------+
+| ``'V'`` | The ISO week-based week number as a decimal number. If the result  |
+|         | is a single digit, it is prefixed with 0. The modified command     |
+|         | ``%OV`` produces the locale's alternative representation.          |
++---------+--------------------------------------------------------------------+
+| ``'w'`` | The weekday as a decimal number (0-6), where Sunday is 0.          |
+|         | The modified command ``%Ow`` produces the locale's alternative     |
+|         | representation.                                                    |
++---------+--------------------------------------------------------------------+
+| ``'W'`` | The week number of the year as a decimal number. The first Monday  |
+|         | of the year is the first day of week 01. Days of the same year     |
+|         | prior to that are in week 00. If the result is a single digit, it  |
+|         | is prefixed with 0. The modified command ``%OW`` produces the      |
+|         | locale's alternative representation.                               |
++---------+--------------------------------------------------------------------+
+| ``'x'`` | The date representation, e.g. "11/12/55". The modified command     |
+|         | ``%Ex`` produces the locale's alternate date representation.       |
++---------+--------------------------------------------------------------------+
+| ``'X'`` | The time representation, e.g. "10:04:00". The modified command     |
+|         | ``%EX`` produces the locale's alternate time representation.       |
++---------+--------------------------------------------------------------------+
+| ``'y'`` | The last two decimal digits of the year. If the result is a single |
+|         | digit it is prefixed by 0. The modified command ``%Oy`` produces   |
+|         | the locale's alternative representation. The modified command      |
+|         | ``%Ey`` produces the locale's alternative representation of offset |
+|         | from ``%EC`` (year only).                                          |
++---------+--------------------------------------------------------------------+
+| ``'Y'`` | The year as a decimal number. If the result is less than four      |
+|         | digits it is left-padded with 0 to four digits. The modified       |
+|         | command ``%EY`` produces the locale's alternative full year        |
+|         | representation.                                                    |
++---------+--------------------------------------------------------------------+
+| ``'z'`` | The offset from UTC in the ISO 8601:2004 format. For example -0430 |
+|         | refers to 4 hours 30 minutes behind UTC. If the offset is zero,    |
+|         | +0000 is used. The modified commands ``%Ez`` and ``%Oz`` insert a  |
+|         | ``:`` between the hours and minutes: -04:30. If the offset         |
+|         | information is not available, an exception of type                 |
+|         | ``format_error`` is thrown.                                        |
++---------+--------------------------------------------------------------------+
+| ``'Z'`` | The time zone abbreviation. If the time zone abbreviation is not   |
+|         | available, an exception of type ``format_error`` is thrown.        |
++---------+--------------------------------------------------------------------+
+| ``'%'`` | A % character.                                                     |
++---------+--------------------------------------------------------------------+
+
+Specifiers that have a calendaric component such as ``'d'`` (the day of month)
+are valid only for ``std::tm`` and time points but not durations.
+
+.. range-specs:
+
+Range Format Specifications
+===========================
+
+Format specifications for range types have the following syntax:
+
+.. productionlist:: sf
+   range_format_spec: [":" [`underlying_spec`]]
+
+The `underlying_spec` is parsed based on the formatter of the range's
+reference type.
+
+By default, a range of characters or strings is printed escaped and quoted. But
+if any `underlying_spec` is provided (even if it is empty), then the characters
+or strings are printed according to the provided specification.
+
+Examples::
+
+  fmt::format("{}", std::vector{10, 20, 30});
+  // Result: [10, 20, 30]
+  fmt::format("{::#x}", std::vector{10, 20, 30});
+  // Result: [0xa, 0x14, 0x1e]
+  fmt::format("{}", vector{'h', 'e', 'l', 'l', 'o'});
+  // Result: ['h', 'e', 'l', 'l', 'o']
+  fmt::format("{::}", vector{'h', 'e', 'l', 'l', 'o'});
+  // Result: [h, e, l, l, o]
+  fmt::format("{::d}", vector{'h', 'e', 'l', 'l', 'o'});
+  // Result: [104, 101, 108, 108, 111]
+
 .. _formatexamples:
 
 Format Examples
@@ -391,7 +593,7 @@ Using type-specific formatting::
 
    auto t = tm();
    t.tm_year = 2010 - 1900;
-   t.tm_mon = 6;
+   t.tm_mon = 7;
    t.tm_mday = 4;
    t.tm_hour = 12;
    t.tm_min = 15;
@@ -401,7 +603,7 @@ Using type-specific formatting::
 
 Using the comma as a thousands separator::
 
-   #include <fmt/locale.h>
+   #include <fmt/format.h>
 
    auto s = fmt::format(std::locale("en_US.UTF-8"), "{:L}", 1234567890);
    // s == "1,234,567,890"

doc/usage.rst

@@ -15,7 +15,7 @@ Building the Library
 
 The included `CMake build script`__ can be used to build the fmt
 library on a wide range of platforms. CMake is freely available for
-download from http://www.cmake.org/download/.
+download from https://www.cmake.org/download/.
 
 __ https://github.com/fmtlib/fmt/blob/master/CMakeLists.txt
 
@@ -50,7 +50,15 @@ To build a `shared library`__ set the ``BUILD_SHARED_LIBS`` CMake variable to
 
   cmake -DBUILD_SHARED_LIBS=TRUE ...
 
-__ http://en.wikipedia.org/wiki/Library_%28computing%29#Shared_libraries
+__ https://en.wikipedia.org/wiki/Library_%28computing%29#Shared_libraries
+
+
+To build a `static library` with position independent code (required if the main
+consumer of the fmt library is a shared library i.e. a Python extension) set the
+``CMAKE_POSITION_INDEPENDENT_CODE`` CMake variable to ``TRUE``::
+
+  cmake -DCMAKE_POSITION_INDEPENDENT_CODE=TRUE ...
+
 
 Installing the Library
 ======================
@@ -83,6 +91,49 @@ Setting up your target to use a header-only version of ``fmt`` is equally easy::
 
    target_link_libraries(<your-target> PRIVATE fmt::fmt-header-only)
 
+Usage with build2
+=================
+
+You can use `build2 <https://build2.org>`_, a dependency manager and a
+build-system combined, to use ``fmt``.
+
+Currently this package is available in these package repositories:
+
+- **https://cppget.org/fmt/** for released and published versions.
+- `The git repository with the sources of the build2 package of fmt <https://github.com/build2-packaging/fmt.git>`_
+  for unreleased or custom revisions of ``fmt``.
+
+**Usage:**
+
+- ``build2`` package name: ``fmt``
+- Library target name : ``lib{fmt}``
+
+For example, to make your ``build2`` project depend on ``fmt``:
+
+- Add one of the repositories to your configurations, or in your
+  ``repositories.manifest``, if not already there::
+
+    :
+    role: prerequisite
+    location: https://pkg.cppget.org/1/stable
+
+- Add this package as a dependency to your ``./manifest`` file
+  (example for ``v7.0.x``)::
+
+    depends: fmt ~7.0.0
+
+- Import the target and use it as a prerequisite to your own target
+  using `fmt` in the appropriate ``buildfile``::
+
+    import fmt = fmt%lib{fmt}
+    lib{mylib} : cxx{**} ... $fmt
+
+Then build your project as usual with `b` or `bdep update`.
+
+For ``build2`` newcomers or to get more details and use cases, you can read the
+``build2``
+`toolchain introduction <https://build2.org/build2-toolchain/doc/build2-toolchain-intro.xhtml>`_.
+
 Building the Documentation
 ==========================
 
@@ -130,6 +181,18 @@ The fmt port in vcpkg is kept up to date by Microsoft team members and community
 contributors. If the version is out of date, please `create an issue or pull
 request <https://github.com/Microsoft/vcpkg>`__ on the vcpkg repository.
 
+LHelper
+=======
+
+You can download and install fmt using
+`lhelper <https://github.com/franko/lhelper>`__ dependency manager::
+
+  lhelper activate <some-environment>
+  lhelper install fmt
+
+All the recipes for lhelper are kept in the
+`lhelper's recipe <https://github.com/franko/lhelper-recipes>`__ repository.
+
 Android NDK
 ===========
 
@@ -139,11 +202,11 @@ For an example of using fmt with Android NDK, see the
 `android-ndk-example <https://github.com/fmtlib/android-ndk-example>`_
 repository.
 
-__ https://github.com/fmtlib/fmt/blob/master/Android.mk
+__ https://github.com/fmtlib/fmt/blob/master/support/Android.mk
 
 Homebrew
 ========
 
-fmt can be installed on OS X using `Homebrew <http://brew.sh/>`_::
+fmt can be installed on OS X using `Homebrew <https://brew.sh/>`_::
 
   brew install fmt

fmt.pri

@@ -0,0 +1 @@
+QMAKE_CXXFLAGS += -isystem $$PWD/include

fmt_src.pri

@@ -0,0 +1,4 @@
+HEADERS +=
+
+SOURCES += \
+    $$PWD/src/format.cc

include/fmt/args.h

@@ -0,0 +1,234 @@
+// Formatting library for C++ - dynamic argument lists
+//
+// Copyright (c) 2012 - present, Victor Zverovich
+// All rights reserved.
+//
+// For the license information refer to format.h.
+
+#ifndef FMT_ARGS_H_
+#define FMT_ARGS_H_
+
+#include <functional>  // std::reference_wrapper
+#include <memory>      // std::unique_ptr
+#include <vector>
+
+#include "core.h"
+
+FMT_BEGIN_NAMESPACE
+
+namespace detail {
+
+template <typename T> struct is_reference_wrapper : std::false_type {};
+template <typename T>
+struct is_reference_wrapper<std::reference_wrapper<T>> : std::true_type {};
+
+template <typename T> const T& unwrap(const T& v) { return v; }
+template <typename T> const T& unwrap(const std::reference_wrapper<T>& v) {
+  return static_cast<const T&>(v);
+}
+
+class dynamic_arg_list {
+  // Workaround for clang's -Wweak-vtables. Unlike for regular classes, for
+  // templates it doesn't complain about inability to deduce single translation
+  // unit for placing vtable. So storage_node_base is made a fake template.
+  template <typename = void> struct node {
+    virtual ~node() = default;
+    std::unique_ptr<node<>> next;
+  };
+
+  template <typename T> struct typed_node : node<> {
+    T value;
+
+    template <typename Arg>
+    FMT_CONSTEXPR typed_node(const Arg& arg) : value(arg) {}
+
+    template <typename Char>
+    FMT_CONSTEXPR typed_node(const basic_string_view<Char>& arg)
+        : value(arg.data(), arg.size()) {}
+  };
+
+  std::unique_ptr<node<>> head_;
+
+ public:
+  template <typename T, typename Arg> const T& push(const Arg& arg) {
+    auto new_node = std::unique_ptr<typed_node<T>>(new typed_node<T>(arg));
+    auto& value = new_node->value;
+    new_node->next = std::move(head_);
+    head_ = std::move(new_node);
+    return value;
+  }
+};
+}  // namespace detail
+
+/**
+  \rst
+  A dynamic version of `fmt::format_arg_store`.
+  It's equipped with a storage to potentially temporary objects which lifetimes
+  could be shorter than the format arguments object.
+
+  It can be implicitly converted into `~fmt::basic_format_args` for passing
+  into type-erased formatting functions such as `~fmt::vformat`.
+  \endrst
+ */
+template <typename Context>
+class dynamic_format_arg_store
+#if FMT_GCC_VERSION && FMT_GCC_VERSION < 409
+    // Workaround a GCC template argument substitution bug.
+    : public basic_format_args<Context>
+#endif
+{
+ private:
+  using char_type = typename Context::char_type;
+
+  template <typename T> struct need_copy {
+    static constexpr detail::type mapped_type =
+        detail::mapped_type_constant<T, Context>::value;
+
+    enum {
+      value = !(detail::is_reference_wrapper<T>::value ||
+                std::is_same<T, basic_string_view<char_type>>::value ||
+                std::is_same<T, detail::std_string_view<char_type>>::value ||
+                (mapped_type != detail::type::cstring_type &&
+                 mapped_type != detail::type::string_type &&
+                 mapped_type != detail::type::custom_type))
+    };
+  };
+
+  template <typename T>
+  using stored_type = conditional_t<
+      std::is_convertible<T, std::basic_string<char_type>>::value &&
+          !detail::is_reference_wrapper<T>::value,
+      std::basic_string<char_type>, T>;
+
+  // Storage of basic_format_arg must be contiguous.
+  std::vector<basic_format_arg<Context>> data_;
+  std::vector<detail::named_arg_info<char_type>> named_info_;
+
+  // Storage of arguments not fitting into basic_format_arg must grow
+  // without relocation because items in data_ refer to it.
+  detail::dynamic_arg_list dynamic_args_;
+
+  friend class basic_format_args<Context>;
+
+  unsigned long long get_types() const {
+    return detail::is_unpacked_bit | data_.size() |
+           (named_info_.empty()
+                ? 0ULL
+                : static_cast<unsigned long long>(detail::has_named_args_bit));
+  }
+
+  const basic_format_arg<Context>* data() const {
+    return named_info_.empty() ? data_.data() : data_.data() + 1;
+  }
+
+  template <typename T> void emplace_arg(const T& arg) {
+    data_.emplace_back(detail::make_arg<Context>(arg));
+  }
+
+  template <typename T>
+  void emplace_arg(const detail::named_arg<char_type, T>& arg) {
+    if (named_info_.empty()) {
+      constexpr const detail::named_arg_info<char_type>* zero_ptr{nullptr};
+      data_.insert(data_.begin(), {zero_ptr, 0});
+    }
+    data_.emplace_back(detail::make_arg<Context>(detail::unwrap(arg.value)));
+    auto pop_one = [](std::vector<basic_format_arg<Context>>* data) {
+      data->pop_back();
+    };
+    std::unique_ptr<std::vector<basic_format_arg<Context>>, decltype(pop_one)>
+        guard{&data_, pop_one};
+    named_info_.push_back({arg.name, static_cast<int>(data_.size() - 2u)});
+    data_[0].value_.named_args = {named_info_.data(), named_info_.size()};
+    guard.release();
+  }
+
+ public:
+  constexpr dynamic_format_arg_store() = default;
+
+  /**
+    \rst
+    Adds an argument into the dynamic store for later passing to a formatting
+    function.
+
+    Note that custom types and string types (but not string views) are copied
+    into the store dynamically allocating memory if necessary.
+
+    **Example**::
+
+      fmt::dynamic_format_arg_store<fmt::format_context> store;
+      store.push_back(42);
+      store.push_back("abc");
+      store.push_back(1.5f);
+      std::string result = fmt::vformat("{} and {} and {}", store);
+    \endrst
+  */
+  template <typename T> void push_back(const T& arg) {
+    if (detail::const_check(need_copy<T>::value))
+      emplace_arg(dynamic_args_.push<stored_type<T>>(arg));
+    else
+      emplace_arg(detail::unwrap(arg));
+  }
+
+  /**
+    \rst
+    Adds a reference to the argument into the dynamic store for later passing to
+    a formatting function.
+
+    **Example**::
+
+      fmt::dynamic_format_arg_store<fmt::format_context> store;
+      char band[] = "Rolling Stones";
+      store.push_back(std::cref(band));
+      band[9] = 'c'; // Changing str affects the output.
+      std::string result = fmt::vformat("{}", store);
+      // result == "Rolling Scones"
+    \endrst
+  */
+  template <typename T> void push_back(std::reference_wrapper<T> arg) {
+    static_assert(
+        need_copy<T>::value,
+        "objects of built-in types and string views are always copied");
+    emplace_arg(arg.get());
+  }
+
+  /**
+    Adds named argument into the dynamic store for later passing to a formatting
+    function. ``std::reference_wrapper`` is supported to avoid copying of the
+    argument. The name is always copied into the store.
+  */
+  template <typename T>
+  void push_back(const detail::named_arg<char_type, T>& arg) {
+    const char_type* arg_name =
+        dynamic_args_.push<std::basic_string<char_type>>(arg.name).c_str();
+    if (detail::const_check(need_copy<T>::value)) {
+      emplace_arg(
+          fmt::arg(arg_name, dynamic_args_.push<stored_type<T>>(arg.value)));
+    } else {
+      emplace_arg(fmt::arg(arg_name, arg.value));
+    }
+  }
+
+  /** Erase all elements from the store */
+  void clear() {
+    data_.clear();
+    named_info_.clear();
+    dynamic_args_ = detail::dynamic_arg_list();
+  }
+
+  /**
+    \rst
+    Reserves space to store at least *new_cap* arguments including
+    *new_cap_named* named arguments.
+    \endrst
+  */
+  void reserve(size_t new_cap, size_t new_cap_named) {
+    FMT_ASSERT(new_cap >= new_cap_named,
+               "Set of arguments includes set of named arguments");
+    data_.reserve(new_cap);
+    named_info_.reserve(new_cap_named);
+  }
+};
+
+FMT_END_NAMESPACE
+
+#endif  // FMT_ARGS_H_

include/fmt/color.h

@@ -11,6 +11,7 @@
 #include "format.h"
 
 FMT_BEGIN_NAMESPACE
+FMT_BEGIN_EXPORT
 
 enum class color : uint32_t {
   alice_blue = 0xF0F8FF,               // rgb(240,248,255)
@@ -177,9 +178,13 @@ enum class terminal_color : uint8_t {
 
 enum class emphasis : uint8_t {
   bold = 1,
-  italic = 1 << 1,
-  underline = 1 << 2,
-  strikethrough = 1 << 3
+  faint = 1 << 1,
+  italic = 1 << 2,
+  underline = 1 << 3,
+  blink = 1 << 4,
+  reverse = 1 << 5,
+  conceal = 1 << 6,
+  strikethrough = 1 << 7,
 };
 
 // rgb is a struct for red, green and blue colors.
@@ -202,17 +207,16 @@ namespace detail {
 
 // color is a struct of either a rgb color or a terminal color.
 struct color_type {
-  FMT_CONSTEXPR color_type() FMT_NOEXCEPT : is_rgb(), value{} {}
-  FMT_CONSTEXPR color_type(color rgb_color) FMT_NOEXCEPT : is_rgb(true),
-                                                           value{} {
+  FMT_CONSTEXPR color_type() noexcept : is_rgb(), value{} {}
+  FMT_CONSTEXPR color_type(color rgb_color) noexcept : is_rgb(true), value{} {
     value.rgb_color = static_cast<uint32_t>(rgb_color);
   }
-  FMT_CONSTEXPR color_type(rgb rgb_color) FMT_NOEXCEPT : is_rgb(true), value{} {
+  FMT_CONSTEXPR color_type(rgb rgb_color) noexcept : is_rgb(true), value{} {
     value.rgb_color = (static_cast<uint32_t>(rgb_color.r) << 16) |
                       (static_cast<uint32_t>(rgb_color.g) << 8) | rgb_color.b;
   }
-  FMT_CONSTEXPR color_type(terminal_color term_color) FMT_NOEXCEPT : is_rgb(),
-                                                                     value{} {
+  FMT_CONSTEXPR color_type(terminal_color term_color) noexcept
+      : is_rgb(), value{} {
     value.term_color = static_cast<uint8_t>(term_color);
   }
   bool is_rgb;
@@ -223,13 +227,11 @@ struct color_type {
 };
 }  // namespace detail
 
-// Experimental text formatting support.
+/** A text style consisting of foreground and background colors and emphasis. */
 class text_style {
  public:
-  FMT_CONSTEXPR text_style(emphasis em = emphasis()) FMT_NOEXCEPT
-      : set_foreground_color(),
-        set_background_color(),
-        ems(em) {}
+  FMT_CONSTEXPR text_style(emphasis em = emphasis()) noexcept
+      : set_foreground_color(), set_background_color(), ems(em) {}
 
   FMT_CONSTEXPR text_style& operator|=(const text_style& rhs) {
     if (!set_foreground_color) {
@@ -260,63 +262,32 @@ class text_style {
     return lhs |= rhs;
   }
 
-  FMT_CONSTEXPR text_style& operator&=(const text_style& rhs) {
-    if (!set_foreground_color) {
-      set_foreground_color = rhs.set_foreground_color;
-      foreground_color = rhs.foreground_color;
-    } else if (rhs.set_foreground_color) {
-      if (!foreground_color.is_rgb || !rhs.foreground_color.is_rgb)
-        FMT_THROW(format_error("can't AND a terminal color"));
-      foreground_color.value.rgb_color &= rhs.foreground_color.value.rgb_color;
-    }
-
-    if (!set_background_color) {
-      set_background_color = rhs.set_background_color;
-      background_color = rhs.background_color;
-    } else if (rhs.set_background_color) {
-      if (!background_color.is_rgb || !rhs.background_color.is_rgb)
-        FMT_THROW(format_error("can't AND a terminal color"));
-      background_color.value.rgb_color &= rhs.background_color.value.rgb_color;
-    }
-
-    ems = static_cast<emphasis>(static_cast<uint8_t>(ems) &
-                                static_cast<uint8_t>(rhs.ems));
-    return *this;
-  }
-
-  friend FMT_CONSTEXPR text_style operator&(text_style lhs,
-                                            const text_style& rhs) {
-    return lhs &= rhs;
-  }
-
-  FMT_CONSTEXPR bool has_foreground() const FMT_NOEXCEPT {
+  FMT_CONSTEXPR bool has_foreground() const noexcept {
     return set_foreground_color;
   }
-  FMT_CONSTEXPR bool has_background() const FMT_NOEXCEPT {
+  FMT_CONSTEXPR bool has_background() const noexcept {
     return set_background_color;
   }
-  FMT_CONSTEXPR bool has_emphasis() const FMT_NOEXCEPT {
+  FMT_CONSTEXPR bool has_emphasis() const noexcept {
     return static_cast<uint8_t>(ems) != 0;
   }
-  FMT_CONSTEXPR detail::color_type get_foreground() const FMT_NOEXCEPT {
+  FMT_CONSTEXPR detail::color_type get_foreground() const noexcept {
     FMT_ASSERT(has_foreground(), "no foreground specified for this style");
     return foreground_color;
   }
-  FMT_CONSTEXPR detail::color_type get_background() const FMT_NOEXCEPT {
+  FMT_CONSTEXPR detail::color_type get_background() const noexcept {
     FMT_ASSERT(has_background(), "no background specified for this style");
     return background_color;
   }
-  FMT_CONSTEXPR emphasis get_emphasis() const FMT_NOEXCEPT {
+  FMT_CONSTEXPR emphasis get_emphasis() const noexcept {
     FMT_ASSERT(has_emphasis(), "no emphasis specified for this style");
     return ems;
   }
 
  private:
   FMT_CONSTEXPR text_style(bool is_foreground,
-                           detail::color_type text_color) FMT_NOEXCEPT
-      : set_foreground_color(),
-        set_background_color(),
-        ems() {
+                           detail::color_type text_color) noexcept
+      : set_foreground_color(), set_background_color(), ems() {
     if (is_foreground) {
       foreground_color = text_color;
       set_foreground_color = true;
@@ -326,10 +297,9 @@ class text_style {
     }
   }
 
-  friend FMT_CONSTEXPR_DECL text_style fg(detail::color_type foreground)
-      FMT_NOEXCEPT;
-  friend FMT_CONSTEXPR_DECL text_style bg(detail::color_type background)
-      FMT_NOEXCEPT;
+  friend FMT_CONSTEXPR text_style fg(detail::color_type foreground) noexcept;
+
+  friend FMT_CONSTEXPR text_style bg(detail::color_type background) noexcept;
 
   detail::color_type foreground_color;
   detail::color_type background_color;
@@ -338,15 +308,17 @@ class text_style {
   emphasis ems;
 };
 
-FMT_CONSTEXPR text_style fg(detail::color_type foreground) FMT_NOEXCEPT {
-  return text_style(/*is_foreground=*/true, foreground);
+/** Creates a text style from the foreground (text) color. */
+FMT_CONSTEXPR inline text_style fg(detail::color_type foreground) noexcept {
+  return text_style(true, foreground);
 }
 
-FMT_CONSTEXPR text_style bg(detail::color_type background) FMT_NOEXCEPT {
-  return text_style(/*is_foreground=*/false, background);
+/** Creates a text style from the background color. */
+FMT_CONSTEXPR inline text_style bg(detail::color_type background) noexcept {
+  return text_style(false, background);
 }
 
-FMT_CONSTEXPR text_style operator|(emphasis lhs, emphasis rhs) FMT_NOEXCEPT {
+FMT_CONSTEXPR inline text_style operator|(emphasis lhs, emphasis rhs) noexcept {
   return text_style(lhs) | rhs;
 }
 
@@ -354,11 +326,11 @@ namespace detail {
 
 template <typename Char> struct ansi_color_escape {
   FMT_CONSTEXPR ansi_color_escape(detail::color_type text_color,
-                                  const char* esc) FMT_NOEXCEPT {
+                                  const char* esc) noexcept {
     // If we have a terminal color, we need to output another escape code
     // sequence.
     if (!text_color.is_rgb) {
-      bool is_background = esc == detail::data::background_color;
+      bool is_background = esc == string_view("\x1b[48;2;");
       uint32_t value = text_color.value.term_color;
       // Background ASCII codes are the same as the foreground ones but with
       // 10 more.
@@ -389,17 +361,19 @@ template <typename Char> struct ansi_color_escape {
     to_esc(color.b, buffer + 15, 'm');
     buffer[19] = static_cast<Char>(0);
   }
-  FMT_CONSTEXPR ansi_color_escape(emphasis em) FMT_NOEXCEPT {
-    uint8_t em_codes[4] = {};
-    uint8_t em_bits = static_cast<uint8_t>(em);
-    if (em_bits & static_cast<uint8_t>(emphasis::bold)) em_codes[0] = 1;
-    if (em_bits & static_cast<uint8_t>(emphasis::italic)) em_codes[1] = 3;
-    if (em_bits & static_cast<uint8_t>(emphasis::underline)) em_codes[2] = 4;
-    if (em_bits & static_cast<uint8_t>(emphasis::strikethrough))
-      em_codes[3] = 9;
+  FMT_CONSTEXPR ansi_color_escape(emphasis em) noexcept {
+    uint8_t em_codes[num_emphases] = {};
+    if (has_emphasis(em, emphasis::bold)) em_codes[0] = 1;
+    if (has_emphasis(em, emphasis::faint)) em_codes[1] = 2;
+    if (has_emphasis(em, emphasis::italic)) em_codes[2] = 3;
+    if (has_emphasis(em, emphasis::underline)) em_codes[3] = 4;
+    if (has_emphasis(em, emphasis::blink)) em_codes[4] = 5;
+    if (has_emphasis(em, emphasis::reverse)) em_codes[5] = 7;
+    if (has_emphasis(em, emphasis::conceal)) em_codes[6] = 8;
+    if (has_emphasis(em, emphasis::strikethrough)) em_codes[7] = 9;
 
     size_t index = 0;
-    for (int i = 0; i < 4; ++i) {
+    for (size_t i = 0; i < num_emphases; ++i) {
       if (!em_codes[i]) continue;
       buffer[index++] = static_cast<Char>('\x1b');
       buffer[index++] = static_cast<Char>('[');
@@ -408,71 +382,60 @@ template <typename Char> struct ansi_color_escape {
     }
     buffer[index++] = static_cast<Char>(0);
   }
-  FMT_CONSTEXPR operator const Char*() const FMT_NOEXCEPT { return buffer; }
+  FMT_CONSTEXPR operator const Char*() const noexcept { return buffer; }
 
-  FMT_CONSTEXPR const Char* begin() const FMT_NOEXCEPT { return buffer; }
-  FMT_CONSTEXPR const Char* end() const FMT_NOEXCEPT {
+  FMT_CONSTEXPR const Char* begin() const noexcept { return buffer; }
+  FMT_CONSTEXPR_CHAR_TRAITS const Char* end() const noexcept {
     return buffer + std::char_traits<Char>::length(buffer);
   }
 
  private:
-  Char buffer[7u + 3u * 4u + 1u];
+  static constexpr size_t num_emphases = 8;
+  Char buffer[7u + 3u * num_emphases + 1u];
 
   static FMT_CONSTEXPR void to_esc(uint8_t c, Char* out,
-                                   char delimiter) FMT_NOEXCEPT {
+                                   char delimiter) noexcept {
     out[0] = static_cast<Char>('0' + c / 100);
     out[1] = static_cast<Char>('0' + c / 10 % 10);
     out[2] = static_cast<Char>('0' + c % 10);
     out[3] = static_cast<Char>(delimiter);
   }
+  static FMT_CONSTEXPR bool has_emphasis(emphasis em, emphasis mask) noexcept {
+    return static_cast<uint8_t>(em) & static_cast<uint8_t>(mask);
+  }
 };
 
 template <typename Char>
 FMT_CONSTEXPR ansi_color_escape<Char> make_foreground_color(
-    detail::color_type foreground) FMT_NOEXCEPT {
-  return ansi_color_escape<Char>(foreground, detail::data::foreground_color);
+    detail::color_type foreground) noexcept {
+  return ansi_color_escape<Char>(foreground, "\x1b[38;2;");
 }
 
 template <typename Char>
 FMT_CONSTEXPR ansi_color_escape<Char> make_background_color(
-    detail::color_type background) FMT_NOEXCEPT {
-  return ansi_color_escape<Char>(background, detail::data::background_color);
+    detail::color_type background) noexcept {
+  return ansi_color_escape<Char>(background, "\x1b[48;2;");
 }
 
 template <typename Char>
-FMT_CONSTEXPR ansi_color_escape<Char> make_emphasis(emphasis em) FMT_NOEXCEPT {
+FMT_CONSTEXPR ansi_color_escape<Char> make_emphasis(emphasis em) noexcept {
   return ansi_color_escape<Char>(em);
 }
 
-template <typename Char>
-inline void fputs(const Char* chars, FILE* stream) FMT_NOEXCEPT {
-  std::fputs(chars, stream);
+template <typename Char> inline void reset_color(buffer<Char>& buffer) {
+  auto reset_color = string_view("\x1b[0m");
+  buffer.append(reset_color.begin(), reset_color.end());
 }
 
-template <>
-inline void fputs<wchar_t>(const wchar_t* chars, FILE* stream) FMT_NOEXCEPT {
-  std::fputws(chars, stream);
-}
-
-template <typename Char> inline void reset_color(FILE* stream) FMT_NOEXCEPT {
-  fputs(detail::data::reset_color, stream);
-}
-
-template <> inline void reset_color<wchar_t>(FILE* stream) FMT_NOEXCEPT {
-  fputs(detail::data::wreset_color, stream);
-}
+template <typename T> struct styled_arg {
+  const T& value;
+  text_style style;
+};
 
 template <typename Char>
-inline void reset_color(basic_memory_buffer<Char>& buffer) FMT_NOEXCEPT {
-  const char* begin = data::reset_color;
-  const char* end = begin + sizeof(data::reset_color) - 1;
-  buffer.append(begin, end);
-}
-
-template <typename Char>
-void vformat_to(basic_memory_buffer<Char>& buf, const text_style& ts,
+void vformat_to(buffer<Char>& buf, const text_style& ts,
                 basic_string_view<Char> format_str,
-                basic_format_args<buffer_context<Char>> args) {
+                basic_format_args<buffer_context<type_identity_t<Char>>> args) {
   bool has_style = false;
   if (ts.has_emphasis()) {
     has_style = true;
@@ -489,43 +452,56 @@ void vformat_to(basic_memory_buffer<Char>& buf, const text_style& ts,
     auto background = detail::make_background_color<Char>(ts.get_background());
     buf.append(background.begin(), background.end());
   }
-  detail::vformat_to(buf, format_str, args);
+  detail::vformat_to(buf, format_str, args, {});
   if (has_style) detail::reset_color<Char>(buf);
 }
+
 }  // namespace detail
 
-template <typename S, typename Char = char_t<S>>
-void vprint(std::FILE* f, const text_style& ts, const S& format,
-            basic_format_args<buffer_context<Char>> args) {
-  basic_memory_buffer<Char> buf;
-  detail::vformat_to(buf, ts, to_string_view(format), args);
-  buf.push_back(Char(0));
-  detail::fputs(buf.data(), f);
+inline void vprint(std::FILE* f, const text_style& ts, string_view fmt,
+                   format_args args) {
+  // Legacy wide streams are not supported.
+  auto buf = memory_buffer();
+  detail::vformat_to(buf, ts, fmt, args);
+  if (detail::is_utf8()) {
+    detail::print(f, string_view(buf.begin(), buf.size()));
+    return;
+  }
+  buf.push_back('\0');
+  int result = std::fputs(buf.data(), f);
+  if (result < 0)
+    FMT_THROW(system_error(errno, FMT_STRING("cannot write to file")));
 }
 
 /**
+  \rst
   Formats a string and prints it to the specified file stream using ANSI
   escape sequences to specify text formatting.
-  Example:
+
+  **Example**::
+
     fmt::print(fmt::emphasis::bold | fg(fmt::color::red),
                "Elapsed time: {0:.2f} seconds", 1.23);
+  \endrst
  */
 template <typename S, typename... Args,
           FMT_ENABLE_IF(detail::is_string<S>::value)>
 void print(std::FILE* f, const text_style& ts, const S& format_str,
            const Args&... args) {
-  detail::check_format_string<Args...>(format_str);
-  using context = buffer_context<char_t<S>>;
-  format_arg_store<context, Args...> as{args...};
-  vprint(f, ts, format_str, basic_format_args<context>(as));
+  vprint(f, ts, format_str,
+         fmt::make_format_args<buffer_context<char_t<S>>>(args...));
 }
 
 /**
+  \rst
   Formats a string and prints it to stdout using ANSI escape sequences to
   specify text formatting.
-  Example:
+
+  **Example**::
+
     fmt::print(fmt::emphasis::bold | fg(fmt::color::red),
                "Elapsed time: {0:.2f} seconds", 1.23);
+  \endrst
  */
 template <typename S, typename... Args,
           FMT_ENABLE_IF(detail::is_string<S>::value)>
@@ -538,7 +514,7 @@ inline std::basic_string<Char> vformat(
     const text_style& ts, const S& format_str,
     basic_format_args<buffer_context<type_identity_t<Char>>> args) {
   basic_memory_buffer<Char> buf;
-  detail::vformat_to(buf, ts, to_string_view(format_str), args);
+  detail::vformat_to(buf, ts, detail::to_string_view(format_str), args);
   return fmt::to_string(buf);
 }
 
@@ -557,10 +533,100 @@ inline std::basic_string<Char> vformat(
 template <typename S, typename... Args, typename Char = char_t<S>>
 inline std::basic_string<Char> format(const text_style& ts, const S& format_str,
                                       const Args&... args) {
-  return vformat(ts, to_string_view(format_str),
-                 detail::make_args_checked<Args...>(format_str, args...));
+  return fmt::vformat(ts, detail::to_string_view(format_str),
+                      fmt::make_format_args<buffer_context<Char>>(args...));
 }
 
+/**
+  Formats a string with the given text_style and writes the output to ``out``.
+ */
+template <typename OutputIt, typename Char,
+          FMT_ENABLE_IF(detail::is_output_iterator<OutputIt, Char>::value)>
+OutputIt vformat_to(
+    OutputIt out, const text_style& ts, basic_string_view<Char> format_str,
+    basic_format_args<buffer_context<type_identity_t<Char>>> args) {
+  auto&& buf = detail::get_buffer<Char>(out);
+  detail::vformat_to(buf, ts, format_str, args);
+  return detail::get_iterator(buf, out);
+}
+
+/**
+  \rst
+  Formats arguments with the given text_style, writes the result to the output
+  iterator ``out`` and returns the iterator past the end of the output range.
+
+  **Example**::
+
+    std::vector<char> out;
+    fmt::format_to(std::back_inserter(out),
+                   fmt::emphasis::bold | fg(fmt::color::red), "{}", 42);
+  \endrst
+*/
+template <typename OutputIt, typename S, typename... Args,
+          bool enable = detail::is_output_iterator<OutputIt, char_t<S>>::value&&
+              detail::is_string<S>::value>
+inline auto format_to(OutputIt out, const text_style& ts, const S& format_str,
+                      Args&&... args) ->
+    typename std::enable_if<enable, OutputIt>::type {
+  return vformat_to(out, ts, detail::to_string_view(format_str),
+                    fmt::make_format_args<buffer_context<char_t<S>>>(args...));
+}
+
+template <typename T, typename Char>
+struct formatter<detail::styled_arg<T>, Char> : formatter<T, Char> {
+  template <typename FormatContext>
+  auto format(const detail::styled_arg<T>& arg, FormatContext& ctx) const
+      -> decltype(ctx.out()) {
+    const auto& ts = arg.style;
+    const auto& value = arg.value;
+    auto out = ctx.out();
+
+    bool has_style = false;
+    if (ts.has_emphasis()) {
+      has_style = true;
+      auto emphasis = detail::make_emphasis<Char>(ts.get_emphasis());
+      out = std::copy(emphasis.begin(), emphasis.end(), out);
+    }
+    if (ts.has_foreground()) {
+      has_style = true;
+      auto foreground =
+          detail::make_foreground_color<Char>(ts.get_foreground());
+      out = std::copy(foreground.begin(), foreground.end(), out);
+    }
+    if (ts.has_background()) {
+      has_style = true;
+      auto background =
+          detail::make_background_color<Char>(ts.get_background());
+      out = std::copy(background.begin(), background.end(), out);
+    }
+    out = formatter<T, Char>::format(value, ctx);
+    if (has_style) {
+      auto reset_color = string_view("\x1b[0m");
+      out = std::copy(reset_color.begin(), reset_color.end(), out);
+    }
+    return out;
+  }
+};
+
+/**
+  \rst
+  Returns an argument that will be formatted using ANSI escape sequences,
+  to be used in a formatting function.
+
+  **Example**::
+
+    fmt::print("Elapsed time: {0:.2f} seconds",
+               fmt::styled(1.23, fmt::fg(fmt::color::green) |
+                                 fmt::bg(fmt::color::blue)));
+  \endrst
+ */
+template <typename T>
+FMT_CONSTEXPR auto styled(const T& value, text_style ts)
+    -> detail::styled_arg<remove_cvref_t<T>> {
+  return detail::styled_arg<remove_cvref_t<T>>{value, ts};
+}
+
+FMT_END_EXPORT
 FMT_END_NAMESPACE
 
 #endif  // FMT_COLOR_H_

include/fmt/compile.h

@@ -8,13 +8,17 @@
 #ifndef FMT_COMPILE_H_
 #define FMT_COMPILE_H_
 
-#include <vector>
-
 #include "format.h"
 
 FMT_BEGIN_NAMESPACE
 namespace detail {
 
+template <typename Char, typename InputIt>
+FMT_CONSTEXPR inline counting_iterator copy_str(InputIt begin, InputIt end,
+                                                counting_iterator it) {
+  return it + (end - begin);
+}
+
 // A compile-time string which is compiled into fast formatting code.
 class compiled_string {};
 
@@ -34,352 +38,54 @@ struct is_compiled_string : std::is_base_of<compiled_string, S> {};
     std::string s = fmt::format(FMT_COMPILE("{}"), 42);
   \endrst
  */
-#define FMT_COMPILE(s) FMT_STRING_IMPL(s, fmt::detail::compiled_string)
+#if defined(__cpp_if_constexpr) && defined(__cpp_return_type_deduction)
+#  define FMT_COMPILE(s) \
+    FMT_STRING_IMPL(s, fmt::detail::compiled_string, explicit)
+#else
+#  define FMT_COMPILE(s) FMT_STRING(s)
+#endif
+
+#if FMT_USE_NONTYPE_TEMPLATE_ARGS
+template <typename Char, size_t N,
+          fmt::detail_exported::fixed_string<Char, N> Str>
+struct udl_compiled_string : compiled_string {
+  using char_type = Char;
+  explicit constexpr operator basic_string_view<char_type>() const {
+    return {Str.data, N - 1};
+  }
+};
+#endif
 
 template <typename T, typename... Tail>
 const T& first(const T& value, const Tail&...) {
   return value;
 }
 
-// Part of a compiled format string. It can be either literal text or a
-// replacement field.
-template <typename Char> struct format_part {
-  enum class kind { arg_index, arg_name, text, replacement };
-
-  struct replacement {
-    arg_ref<Char> arg_id;
-    dynamic_format_specs<Char> specs;
-  };
-
-  kind part_kind;
-  union value {
-    int arg_index;
-    basic_string_view<Char> str;
-    replacement repl;
-
-    FMT_CONSTEXPR value(int index = 0) : arg_index(index) {}
-    FMT_CONSTEXPR value(basic_string_view<Char> s) : str(s) {}
-    FMT_CONSTEXPR value(replacement r) : repl(r) {}
-  } val;
-  // Position past the end of the argument id.
-  const Char* arg_id_end = nullptr;
-
-  FMT_CONSTEXPR format_part(kind k = kind::arg_index, value v = {})
-      : part_kind(k), val(v) {}
-
-  static FMT_CONSTEXPR format_part make_arg_index(int index) {
-    return format_part(kind::arg_index, index);
-  }
-  static FMT_CONSTEXPR format_part make_arg_name(basic_string_view<Char> name) {
-    return format_part(kind::arg_name, name);
-  }
-  static FMT_CONSTEXPR format_part make_text(basic_string_view<Char> text) {
-    return format_part(kind::text, text);
-  }
-  static FMT_CONSTEXPR format_part make_replacement(replacement repl) {
-    return format_part(kind::replacement, repl);
-  }
-};
-
-template <typename Char> struct part_counter {
-  unsigned num_parts = 0;
-
-  FMT_CONSTEXPR void on_text(const Char* begin, const Char* end) {
-    if (begin != end) ++num_parts;
-  }
-
-  FMT_CONSTEXPR int on_arg_id() { return ++num_parts, 0; }
-  FMT_CONSTEXPR int on_arg_id(int) { return ++num_parts, 0; }
-  FMT_CONSTEXPR int on_arg_id(basic_string_view<Char>) {
-    return ++num_parts, 0;
-  }
-
-  FMT_CONSTEXPR void on_replacement_field(int, const Char*) {}
-
-  FMT_CONSTEXPR const Char* on_format_specs(int, const Char* begin,
-                                            const Char* end) {
-    // Find the matching brace.
-    unsigned brace_counter = 0;
-    for (; begin != end; ++begin) {
-      if (*begin == '{') {
-        ++brace_counter;
-      } else if (*begin == '}') {
-        if (brace_counter == 0u) break;
-        --brace_counter;
-      }
-    }
-    return begin;
-  }
-
-  FMT_CONSTEXPR void on_error(const char*) {}
-};
-
-// Counts the number of parts in a format string.
-template <typename Char>
-FMT_CONSTEXPR unsigned count_parts(basic_string_view<Char> format_str) {
-  part_counter<Char> counter;
-  parse_format_string<true>(format_str, counter);
-  return counter.num_parts;
-}
-
-template <typename Char, typename PartHandler>
-class format_string_compiler : public error_handler {
- private:
-  using part = format_part<Char>;
-
-  PartHandler handler_;
-  part part_;
-  basic_string_view<Char> format_str_;
-  basic_format_parse_context<Char> parse_context_;
-
- public:
-  FMT_CONSTEXPR format_string_compiler(basic_string_view<Char> format_str,
-                                       PartHandler handler)
-      : handler_(handler),
-        format_str_(format_str),
-        parse_context_(format_str) {}
-
-  FMT_CONSTEXPR void on_text(const Char* begin, const Char* end) {
-    if (begin != end)
-      handler_(part::make_text({begin, to_unsigned(end - begin)}));
-  }
-
-  FMT_CONSTEXPR int on_arg_id() {
-    part_ = part::make_arg_index(parse_context_.next_arg_id());
-    return 0;
-  }
-
-  FMT_CONSTEXPR int on_arg_id(int id) {
-    parse_context_.check_arg_id(id);
-    part_ = part::make_arg_index(id);
-    return 0;
-  }
-
-  FMT_CONSTEXPR int on_arg_id(basic_string_view<Char> id) {
-    part_ = part::make_arg_name(id);
-    return 0;
-  }
-
-  FMT_CONSTEXPR void on_replacement_field(int, const Char* ptr) {
-    part_.arg_id_end = ptr;
-    handler_(part_);
-  }
-
-  FMT_CONSTEXPR const Char* on_format_specs(int, const Char* begin,
-                                            const Char* end) {
-    auto repl = typename part::replacement();
-    dynamic_specs_handler<basic_format_parse_context<Char>> handler(
-        repl.specs, parse_context_);
-    auto it = parse_format_specs(begin, end, handler);
-    if (*it != '}') on_error("missing '}' in format string");
-    repl.arg_id = part_.part_kind == part::kind::arg_index
-                      ? arg_ref<Char>(part_.val.arg_index)
-                      : arg_ref<Char>(part_.val.str);
-    auto part = part::make_replacement(repl);
-    part.arg_id_end = begin;
-    handler_(part);
-    return it;
-  }
-};
-
-// Compiles a format string and invokes handler(part) for each parsed part.
-template <bool IS_CONSTEXPR, typename Char, typename PartHandler>
-FMT_CONSTEXPR void compile_format_string(basic_string_view<Char> format_str,
-                                         PartHandler handler) {
-  parse_format_string<IS_CONSTEXPR>(
-      format_str,
-      format_string_compiler<Char, PartHandler>(format_str, handler));
-}
-
-template <typename OutputIt, typename Context, typename Id>
-void format_arg(
-    basic_format_parse_context<typename Context::char_type>& parse_ctx,
-    Context& ctx, Id arg_id) {
-  ctx.advance_to(visit_format_arg(
-      arg_formatter<OutputIt, typename Context::char_type>(ctx, &parse_ctx),
-      ctx.arg(arg_id)));
-}
-
-// vformat_to is defined in a subnamespace to prevent ADL.
-namespace cf {
-template <typename Context, typename OutputIt, typename CompiledFormat>
-auto vformat_to(OutputIt out, CompiledFormat& cf,
-                basic_format_args<Context> args) -> typename Context::iterator {
-  using char_type = typename Context::char_type;
-  basic_format_parse_context<char_type> parse_ctx(
-      to_string_view(cf.format_str_));
-  Context ctx(out, args);
-
-  const auto& parts = cf.parts();
-  for (auto part_it = std::begin(parts); part_it != std::end(parts);
-       ++part_it) {
-    const auto& part = *part_it;
-    const auto& value = part.val;
-
-    using format_part_t = format_part<char_type>;
-    switch (part.part_kind) {
-    case format_part_t::kind::text: {
-      const auto text = value.str;
-      auto output = ctx.out();
-      auto&& it = reserve(output, text.size());
-      it = std::copy_n(text.begin(), text.size(), it);
-      ctx.advance_to(output);
-      break;
-    }
-
-    case format_part_t::kind::arg_index:
-      advance_to(parse_ctx, part.arg_id_end);
-      detail::format_arg<OutputIt>(parse_ctx, ctx, value.arg_index);
-      break;
-
-    case format_part_t::kind::arg_name:
-      advance_to(parse_ctx, part.arg_id_end);
-      detail::format_arg<OutputIt>(parse_ctx, ctx, value.str);
-      break;
-
-    case format_part_t::kind::replacement: {
-      const auto& arg_id_value = value.repl.arg_id.val;
-      const auto arg = value.repl.arg_id.kind == arg_id_kind::index
-                           ? ctx.arg(arg_id_value.index)
-                           : ctx.arg(arg_id_value.name);
-
-      auto specs = value.repl.specs;
-
-      handle_dynamic_spec<width_checker>(specs.width, specs.width_ref, ctx);
-      handle_dynamic_spec<precision_checker>(specs.precision,
-                                             specs.precision_ref, ctx);
-
-      error_handler h;
-      numeric_specs_checker<error_handler> checker(h, arg.type());
-      if (specs.align == align::numeric) checker.require_numeric_argument();
-      if (specs.sign != sign::none) checker.check_sign();
-      if (specs.alt) checker.require_numeric_argument();
-      if (specs.precision >= 0) checker.check_precision();
-
-      advance_to(parse_ctx, part.arg_id_end);
-      ctx.advance_to(
-          visit_format_arg(arg_formatter<OutputIt, typename Context::char_type>(
-                               ctx, nullptr, &specs),
-                           arg));
-      break;
-    }
-    }
-  }
-  return ctx.out();
-}
-}  // namespace cf
-
-struct basic_compiled_format {};
-
-template <typename S, typename = void>
-struct compiled_format_base : basic_compiled_format {
-  using char_type = char_t<S>;
-  using parts_container = std::vector<detail::format_part<char_type>>;
-
-  parts_container compiled_parts;
-
-  explicit compiled_format_base(basic_string_view<char_type> format_str) {
-    compile_format_string<false>(format_str,
-                                 [this](const format_part<char_type>& part) {
-                                   compiled_parts.push_back(part);
-                                 });
-  }
-
-  const parts_container& parts() const { return compiled_parts; }
-};
-
-template <typename Char, unsigned N> struct format_part_array {
-  format_part<Char> data[N] = {};
-  FMT_CONSTEXPR format_part_array() = default;
-};
-
-template <typename Char, unsigned N>
-FMT_CONSTEXPR format_part_array<Char, N> compile_to_parts(
-    basic_string_view<Char> format_str) {
-  format_part_array<Char, N> parts;
-  unsigned counter = 0;
-  // This is not a lambda for compatibility with older compilers.
-  struct {
-    format_part<Char>* parts;
-    unsigned* counter;
-    FMT_CONSTEXPR void operator()(const format_part<Char>& part) {
-      parts[(*counter)++] = part;
-    }
-  } collector{parts.data, &counter};
-  compile_format_string<true>(format_str, collector);
-  if (counter < N) {
-    parts.data[counter] =
-        format_part<Char>::make_text(basic_string_view<Char>());
-  }
-  return parts;
-}
-
-template <typename T> constexpr const T& constexpr_max(const T& a, const T& b) {
-  return (a < b) ? b : a;
-}
-
-template <typename S>
-struct compiled_format_base<S, enable_if_t<is_compile_string<S>::value>>
-    : basic_compiled_format {
-  using char_type = char_t<S>;
-
-  FMT_CONSTEXPR explicit compiled_format_base(basic_string_view<char_type>) {}
-
-// Workaround for old compilers. Format string compilation will not be
-// performed there anyway.
-#if FMT_USE_CONSTEXPR
-  static FMT_CONSTEXPR_DECL const unsigned num_format_parts =
-      constexpr_max(count_parts(to_string_view(S())), 1u);
-#else
-  static const unsigned num_format_parts = 1;
-#endif
-
-  using parts_container = format_part<char_type>[num_format_parts];
-
-  const parts_container& parts() const {
-    static FMT_CONSTEXPR_DECL const auto compiled_parts =
-        compile_to_parts<char_type, num_format_parts>(
-            detail::to_string_view(S()));
-    return compiled_parts.data;
-  }
-};
-
-template <typename S, typename... Args>
-class compiled_format : private compiled_format_base<S> {
- public:
-  using typename compiled_format_base<S>::char_type;
-
- private:
-  basic_string_view<char_type> format_str_;
-
-  template <typename Context, typename OutputIt, typename CompiledFormat>
-  friend auto cf::vformat_to(OutputIt out, CompiledFormat& cf,
-                             basic_format_args<Context> args) ->
-      typename Context::iterator;
-
- public:
-  compiled_format() = delete;
-  explicit constexpr compiled_format(basic_string_view<char_type> format_str)
-      : compiled_format_base<S>(format_str), format_str_(format_str) {}
-};
-
-#ifdef __cpp_if_constexpr
+#if defined(__cpp_if_constexpr) && defined(__cpp_return_type_deduction)
 template <typename... Args> struct type_list {};
 
 // Returns a reference to the argument at index N from [first, rest...].
 template <int N, typename T, typename... Args>
-constexpr const auto& get(const T& first, const Args&... rest) {
+constexpr const auto& get([[maybe_unused]] const T& first,
+                          [[maybe_unused]] const Args&... rest) {
   static_assert(N < 1 + sizeof...(Args), "index is out of bounds");
   if constexpr (N == 0)
     return first;
   else
-    return get<N - 1>(rest...);
+    return detail::get<N - 1>(rest...);
+}
+
+template <typename Char, typename... Args>
+constexpr int get_arg_index_by_name(basic_string_view<Char> name,
+                                    type_list<Args...>) {
+  return get_arg_index_by_name<Args...>(name);
 }
 
 template <int N, typename> struct get_type_impl;
 
 template <int N, typename... Args> struct get_type_impl<N, type_list<Args...>> {
-  using type = remove_cvref_t<decltype(get<N>(std::declval<Args>()...))>;
+  using type =
+      remove_cvref_t<decltype(detail::get<N>(std::declval<Args>()...))>;
 };
 
 template <int N, typename T>
@@ -392,7 +98,7 @@ template <typename Char> struct text {
   using char_type = Char;
 
   template <typename OutputIt, typename... Args>
-  OutputIt format(OutputIt out, const Args&...) const {
+  constexpr OutputIt format(OutputIt out, const Args&...) const {
     return write<Char>(out, data);
   }
 };
@@ -406,14 +112,42 @@ constexpr text<Char> make_text(basic_string_view<Char> s, size_t pos,
   return {{&s[pos], size}};
 }
 
+template <typename Char> struct code_unit {
+  Char value;
+  using char_type = Char;
+
+  template <typename OutputIt, typename... Args>
+  constexpr OutputIt format(OutputIt out, const Args&...) const {
+    *out++ = value;
+    return out;
+  }
+};
+
+// This ensures that the argument type is convertible to `const T&`.
+template <typename T, int N, typename... Args>
+constexpr const T& get_arg_checked(const Args&... args) {
+  const auto& arg = detail::get<N>(args...);
+  if constexpr (detail::is_named_arg<remove_cvref_t<decltype(arg)>>()) {
+    return arg.value;
+  } else {
+    return arg;
+  }
+}
+
+template <typename Char>
+struct is_compiled_format<code_unit<Char>> : std::true_type {};
+
 // A replacement field that refers to argument N.
 template <typename Char, typename T, int N> struct field {
   using char_type = Char;
 
   template <typename OutputIt, typename... Args>
-  OutputIt format(OutputIt out, const Args&... args) const {
-    // This ensures that the argument type is convertile to `const T&`.
-    const T& arg = get<N>(args...);
+  constexpr OutputIt format(OutputIt out, const Args&... args) const {
+    const T& arg = get_arg_checked<T, N>(args...);
+    if constexpr (std::is_convertible_v<T, basic_string_view<Char>>) {
+      auto s = basic_string_view<Char>(arg);
+      return copy_str<Char>(s.begin(), s.end(), out);
+    }
     return write<Char>(out, arg);
   }
 };
@@ -421,17 +155,50 @@ template <typename Char, typename T, int N> struct field {
 template <typename Char, typename T, int N>
 struct is_compiled_format<field<Char, T, N>> : std::true_type {};
 
+// A replacement field that refers to argument with name.
+template <typename Char> struct runtime_named_field {
+  using char_type = Char;
+  basic_string_view<Char> name;
+
+  template <typename OutputIt, typename T>
+  constexpr static bool try_format_argument(
+      OutputIt& out,
+      // [[maybe_unused]] due to unused-but-set-parameter warning in GCC 7,8,9
+      [[maybe_unused]] basic_string_view<Char> arg_name, const T& arg) {
+    if constexpr (is_named_arg<typename std::remove_cv<T>::type>::value) {
+      if (arg_name == arg.name) {
+        out = write<Char>(out, arg.value);
+        return true;
+      }
+    }
+    return false;
+  }
+
+  template <typename OutputIt, typename... Args>
+  constexpr OutputIt format(OutputIt out, const Args&... args) const {
+    bool found = (try_format_argument(out, name, args) || ...);
+    if (!found) {
+      FMT_THROW(format_error("argument with specified name is not found"));
+    }
+    return out;
+  }
+};
+
+template <typename Char>
+struct is_compiled_format<runtime_named_field<Char>> : std::true_type {};
+
 // A replacement field that refers to argument N and has format specifiers.
 template <typename Char, typename T, int N> struct spec_field {
   using char_type = Char;
-  mutable formatter<T, Char> fmt;
+  formatter<T, Char> fmt;
 
   template <typename OutputIt, typename... Args>
-  OutputIt format(OutputIt out, const Args&... args) const {
-    // This ensures that the argument type is convertile to `const T&`.
-    const T& arg = get<N>(args...);
-    basic_format_context<OutputIt, Char> ctx(out, {});
-    return fmt.format(arg, ctx);
+  constexpr FMT_INLINE OutputIt format(OutputIt out,
+                                       const Args&... args) const {
+    const auto& vargs =
+        fmt::make_format_args<basic_format_context<OutputIt, Char>>(args...);
+    basic_format_context<OutputIt, Char> ctx(out, vargs);
+    return fmt.format(get_arg_checked<T, N>(args...), ctx);
   }
 };
 
@@ -444,7 +211,7 @@ template <typename L, typename R> struct concat {
   using char_type = typename L::char_type;
 
   template <typename OutputIt, typename... Args>
-  OutputIt format(OutputIt out, const Args&... args) const {
+  constexpr OutputIt format(OutputIt out, const Args&... args) const {
     out = lhs.format(out, args...);
     return rhs.format(out, args...);
   }
@@ -489,16 +256,86 @@ constexpr auto parse_tail(T head, S format_str) {
 template <typename T, typename Char> struct parse_specs_result {
   formatter<T, Char> fmt;
   size_t end;
+  int next_arg_id;
 };
 
+enum { manual_indexing_id = -1 };
+
 template <typename T, typename Char>
 constexpr parse_specs_result<T, Char> parse_specs(basic_string_view<Char> str,
-                                                  size_t pos) {
+                                                  size_t pos, int next_arg_id) {
   str.remove_prefix(pos);
-  auto ctx = basic_format_parse_context<Char>(str);
+  auto ctx =
+      compile_parse_context<Char>(str, max_value<int>(), nullptr, next_arg_id);
   auto f = formatter<T, Char>();
   auto end = f.parse(ctx);
-  return {f, pos + (end - str.data()) + 1};
+  return {f, pos + fmt::detail::to_unsigned(end - str.data()),
+          next_arg_id == 0 ? manual_indexing_id : ctx.next_arg_id()};
+}
+
+template <typename Char> struct arg_id_handler {
+  arg_ref<Char> arg_id;
+
+  constexpr int on_auto() {
+    FMT_ASSERT(false, "handler cannot be used with automatic indexing");
+    return 0;
+  }
+  constexpr int on_index(int id) {
+    arg_id = arg_ref<Char>(id);
+    return 0;
+  }
+  constexpr int on_name(basic_string_view<Char> id) {
+    arg_id = arg_ref<Char>(id);
+    return 0;
+  }
+};
+
+template <typename Char> struct parse_arg_id_result {
+  arg_ref<Char> arg_id;
+  const Char* arg_id_end;
+};
+
+template <int ID, typename Char>
+constexpr auto parse_arg_id(const Char* begin, const Char* end) {
+  auto handler = arg_id_handler<Char>{arg_ref<Char>{}};
+  auto arg_id_end = parse_arg_id(begin, end, handler);
+  return parse_arg_id_result<Char>{handler.arg_id, arg_id_end};
+}
+
+template <typename T, typename Enable = void> struct field_type {
+  using type = remove_cvref_t<T>;
+};
+
+template <typename T>
+struct field_type<T, enable_if_t<detail::is_named_arg<T>::value>> {
+  using type = remove_cvref_t<decltype(T::value)>;
+};
+
+template <typename T, typename Args, size_t END_POS, int ARG_INDEX, int NEXT_ID,
+          typename S>
+constexpr auto parse_replacement_field_then_tail(S format_str) {
+  using char_type = typename S::char_type;
+  constexpr auto str = basic_string_view<char_type>(format_str);
+  constexpr char_type c = END_POS != str.size() ? str[END_POS] : char_type();
+  if constexpr (c == '}') {
+    return parse_tail<Args, END_POS + 1, NEXT_ID>(
+        field<char_type, typename field_type<T>::type, ARG_INDEX>(),
+        format_str);
+  } else if constexpr (c != ':') {
+    FMT_THROW(format_error("expected ':'"));
+  } else {
+    constexpr auto result = parse_specs<typename field_type<T>::type>(
+        str, END_POS + 1, NEXT_ID == manual_indexing_id ? 0 : NEXT_ID);
+    if constexpr (result.end >= str.size() || str[result.end] != '}') {
+      FMT_THROW(format_error("expected '}'"));
+      return 0;
+    } else {
+      return parse_tail<Args, result.end + 1, result.next_arg_id>(
+          spec_field<char_type, typename field_type<T>::type, ARG_INDEX>{
+              result.fmt},
+          format_str);
+    }
+  }
 }
 
 // Compiles a non-empty format string and returns the compiled representation
@@ -506,160 +343,192 @@ constexpr parse_specs_result<T, Char> parse_specs(basic_string_view<Char> str,
 template <typename Args, size_t POS, int ID, typename S>
 constexpr auto compile_format_string(S format_str) {
   using char_type = typename S::char_type;
-  constexpr basic_string_view<char_type> str = format_str;
+  constexpr auto str = basic_string_view<char_type>(format_str);
   if constexpr (str[POS] == '{') {
-    if (POS + 1 == str.size())
-      throw format_error("unmatched '{' in format string");
+    if constexpr (POS + 1 == str.size())
+      FMT_THROW(format_error("unmatched '{' in format string"));
     if constexpr (str[POS + 1] == '{') {
       return parse_tail<Args, POS + 2, ID>(make_text(str, POS, 1), format_str);
-    } else if constexpr (str[POS + 1] == '}') {
-      using type = get_type<ID, Args>;
-      return parse_tail<Args, POS + 2, ID + 1>(field<char_type, type, ID>(),
-                                               format_str);
-    } else if constexpr (str[POS + 1] == ':') {
-      using type = get_type<ID, Args>;
-      constexpr auto result = parse_specs<type>(str, POS + 2);
-      return parse_tail<Args, result.end, ID + 1>(
-          spec_field<char_type, type, ID>{result.fmt}, format_str);
+    } else if constexpr (str[POS + 1] == '}' || str[POS + 1] == ':') {
+      static_assert(ID != manual_indexing_id,
+                    "cannot switch from manual to automatic argument indexing");
+      constexpr auto next_id =
+          ID != manual_indexing_id ? ID + 1 : manual_indexing_id;
+      return parse_replacement_field_then_tail<get_type<ID, Args>, Args,
+                                               POS + 1, ID, next_id>(
+          format_str);
     } else {
-      return unknown_format();
+      constexpr auto arg_id_result =
+          parse_arg_id<ID>(str.data() + POS + 1, str.data() + str.size());
+      constexpr auto arg_id_end_pos = arg_id_result.arg_id_end - str.data();
+      constexpr char_type c =
+          arg_id_end_pos != str.size() ? str[arg_id_end_pos] : char_type();
+      static_assert(c == '}' || c == ':', "missing '}' in format string");
+      if constexpr (arg_id_result.arg_id.kind == arg_id_kind::index) {
+        static_assert(
+            ID == manual_indexing_id || ID == 0,
+            "cannot switch from automatic to manual argument indexing");
+        constexpr auto arg_index = arg_id_result.arg_id.val.index;
+        return parse_replacement_field_then_tail<get_type<arg_index, Args>,
+                                                 Args, arg_id_end_pos,
+                                                 arg_index, manual_indexing_id>(
+            format_str);
+      } else if constexpr (arg_id_result.arg_id.kind == arg_id_kind::name) {
+        constexpr auto arg_index =
+            get_arg_index_by_name(arg_id_result.arg_id.val.name, Args{});
+        if constexpr (arg_index >= 0) {
+          constexpr auto next_id =
+              ID != manual_indexing_id ? ID + 1 : manual_indexing_id;
+          return parse_replacement_field_then_tail<
+              decltype(get_type<arg_index, Args>::value), Args, arg_id_end_pos,
+              arg_index, next_id>(format_str);
+        } else if constexpr (c == '}') {
+          return parse_tail<Args, arg_id_end_pos + 1, ID>(
+              runtime_named_field<char_type>{arg_id_result.arg_id.val.name},
+              format_str);
+        } else if constexpr (c == ':') {
+          return unknown_format();  // no type info for specs parsing
+        }
+      }
     }
   } else if constexpr (str[POS] == '}') {
-    if (POS + 1 == str.size())
-      throw format_error("unmatched '}' in format string");
+    if constexpr (POS + 1 == str.size())
+      FMT_THROW(format_error("unmatched '}' in format string"));
     return parse_tail<Args, POS + 2, ID>(make_text(str, POS, 1), format_str);
   } else {
     constexpr auto end = parse_text(str, POS + 1);
-    return parse_tail<Args, end, ID>(make_text(str, POS, end - POS),
-                                     format_str);
+    if constexpr (end - POS > 1) {
+      return parse_tail<Args, end, ID>(make_text(str, POS, end - POS),
+                                       format_str);
+    } else {
+      return parse_tail<Args, end, ID>(code_unit<char_type>{str[POS]},
+                                       format_str);
+    }
   }
 }
 
 template <typename... Args, typename S,
-          FMT_ENABLE_IF(is_compile_string<S>::value ||
-                        detail::is_compiled_string<S>::value)>
+          FMT_ENABLE_IF(detail::is_compiled_string<S>::value)>
 constexpr auto compile(S format_str) {
-  constexpr basic_string_view<typename S::char_type> str = format_str;
+  constexpr auto str = basic_string_view<typename S::char_type>(format_str);
   if constexpr (str.size() == 0) {
     return detail::make_text(str, 0, 0);
   } else {
     constexpr auto result =
         detail::compile_format_string<detail::type_list<Args...>, 0, 0>(
             format_str);
-    if constexpr (std::is_same<remove_cvref_t<decltype(result)>,
-                               detail::unknown_format>()) {
-      return detail::compiled_format<S, Args...>(to_string_view(format_str));
-    } else {
-      return result;
-    }
+    return result;
   }
 }
-#else
-template <typename... Args, typename S,
-          FMT_ENABLE_IF(is_compile_string<S>::value)>
-constexpr auto compile(S format_str) -> detail::compiled_format<S, Args...> {
-  return detail::compiled_format<S, Args...>(to_string_view(format_str));
-}
-#endif  // __cpp_if_constexpr
-
-// Compiles the format string which must be a string literal.
-template <typename... Args, typename Char, size_t N>
-auto compile(const Char (&format_str)[N])
-    -> detail::compiled_format<const Char*, Args...> {
-  return detail::compiled_format<const Char*, Args...>(
-      basic_string_view<Char>(format_str, N - 1));
-}
+#endif  // defined(__cpp_if_constexpr) && defined(__cpp_return_type_deduction)
 }  // namespace detail
 
-// DEPRECATED! use FMT_COMPILE instead.
-template <typename... Args>
-FMT_DEPRECATED auto compile(const Args&... args)
-    -> decltype(detail::compile(args...)) {
-  return detail::compile(args...);
-}
+FMT_BEGIN_EXPORT
 
-#if FMT_USE_CONSTEXPR
-#  ifdef __cpp_if_constexpr
+#if defined(__cpp_if_constexpr) && defined(__cpp_return_type_deduction)
 
 template <typename CompiledFormat, typename... Args,
           typename Char = typename CompiledFormat::char_type,
           FMT_ENABLE_IF(detail::is_compiled_format<CompiledFormat>::value)>
 FMT_INLINE std::basic_string<Char> format(const CompiledFormat& cf,
                                           const Args&... args) {
-  basic_memory_buffer<Char> buffer;
-  detail::buffer<Char>& base = buffer;
-  cf.format(std::back_inserter(base), args...);
-  return to_string(buffer);
+  auto s = std::basic_string<Char>();
+  cf.format(std::back_inserter(s), args...);
+  return s;
 }
 
 template <typename OutputIt, typename CompiledFormat, typename... Args,
           FMT_ENABLE_IF(detail::is_compiled_format<CompiledFormat>::value)>
-OutputIt format_to(OutputIt out, const CompiledFormat& cf,
-                   const Args&... args) {
+constexpr FMT_INLINE OutputIt format_to(OutputIt out, const CompiledFormat& cf,
+                                        const Args&... args) {
   return cf.format(out, args...);
 }
-#  endif  // __cpp_if_constexpr
-#endif    // FMT_USE_CONSTEXPR
-
-template <typename CompiledFormat, typename... Args,
-          typename Char = typename CompiledFormat::char_type,
-          FMT_ENABLE_IF(std::is_base_of<detail::basic_compiled_format,
-                                        CompiledFormat>::value)>
-std::basic_string<Char> format(const CompiledFormat& cf, const Args&... args) {
-  basic_memory_buffer<Char> buffer;
-  using context = buffer_context<Char>;
-  detail::buffer<Char>& base = buffer;
-  detail::cf::vformat_to<context>(std::back_inserter(base), cf,
-                                  make_format_args<context>(args...));
-  return to_string(buffer);
-}
 
 template <typename S, typename... Args,
           FMT_ENABLE_IF(detail::is_compiled_string<S>::value)>
 FMT_INLINE std::basic_string<typename S::char_type> format(const S&,
                                                            Args&&... args) {
-  constexpr basic_string_view<typename S::char_type> str = S();
-  if (str.size() == 2 && str[0] == '{' && str[1] == '}')
-    return fmt::to_string(detail::first(args...));
+  if constexpr (std::is_same<typename S::char_type, char>::value) {
+    constexpr auto str = basic_string_view<typename S::char_type>(S());
+    if constexpr (str.size() == 2 && str[0] == '{' && str[1] == '}') {
+      const auto& first = detail::first(args...);
+      if constexpr (detail::is_named_arg<
+                        remove_cvref_t<decltype(first)>>::value) {
+        return fmt::to_string(first.value);
+      } else {
+        return fmt::to_string(first);
+      }
+    }
+  }
   constexpr auto compiled = detail::compile<Args...>(S());
-  return format(compiled, std::forward<Args>(args)...);
-}
-
-template <typename OutputIt, typename CompiledFormat, typename... Args,
-          FMT_ENABLE_IF(std::is_base_of<detail::basic_compiled_format,
-                                        CompiledFormat>::value)>
-OutputIt format_to(OutputIt out, const CompiledFormat& cf,
-                   const Args&... args) {
-  using char_type = typename CompiledFormat::char_type;
-  using context = format_context_t<OutputIt, char_type>;
-  return detail::cf::vformat_to<context>(out, cf,
-                                         make_format_args<context>(args...));
+  if constexpr (std::is_same<remove_cvref_t<decltype(compiled)>,
+                             detail::unknown_format>()) {
+    return fmt::format(
+        static_cast<basic_string_view<typename S::char_type>>(S()),
+        std::forward<Args>(args)...);
+  } else {
+    return fmt::format(compiled, std::forward<Args>(args)...);
+  }
 }
 
 template <typename OutputIt, typename S, typename... Args,
           FMT_ENABLE_IF(detail::is_compiled_string<S>::value)>
-OutputIt format_to(OutputIt out, const S&, const Args&... args) {
+FMT_CONSTEXPR OutputIt format_to(OutputIt out, const S&, Args&&... args) {
   constexpr auto compiled = detail::compile<Args...>(S());
-  return format_to(out, compiled, args...);
+  if constexpr (std::is_same<remove_cvref_t<decltype(compiled)>,
+                             detail::unknown_format>()) {
+    return fmt::format_to(
+        out, static_cast<basic_string_view<typename S::char_type>>(S()),
+        std::forward<Args>(args)...);
+  } else {
+    return fmt::format_to(out, compiled, std::forward<Args>(args)...);
+  }
 }
+#endif
 
-template <
-    typename OutputIt, typename CompiledFormat, typename... Args,
-    FMT_ENABLE_IF(detail::is_output_iterator<OutputIt>::value&& std::is_base_of<
-                  detail::basic_compiled_format, CompiledFormat>::value)>
+template <typename OutputIt, typename S, typename... Args,
+          FMT_ENABLE_IF(detail::is_compiled_string<S>::value)>
 format_to_n_result<OutputIt> format_to_n(OutputIt out, size_t n,
-                                         const CompiledFormat& cf,
-                                         const Args&... args) {
-  auto it =
-      format_to(detail::truncating_iterator<OutputIt>(out, n), cf, args...);
-  return {it.base(), it.count()};
+                                         const S& format_str, Args&&... args) {
+  using traits = detail::fixed_buffer_traits;
+  auto buf = detail::iterator_buffer<OutputIt, char, traits>(out, n);
+  format_to(std::back_inserter(buf), format_str, std::forward<Args>(args)...);
+  return {buf.out(), buf.count()};
 }
 
-template <typename CompiledFormat, typename... Args>
-size_t formatted_size(const CompiledFormat& cf, const Args&... args) {
-  return format_to(detail::counting_iterator(), cf, args...).count();
+template <typename S, typename... Args,
+          FMT_ENABLE_IF(detail::is_compiled_string<S>::value)>
+FMT_CONSTEXPR20 size_t formatted_size(const S& format_str,
+                                      const Args&... args) {
+  return fmt::format_to(detail::counting_iterator(), format_str, args...)
+      .count();
 }
 
+template <typename S, typename... Args,
+          FMT_ENABLE_IF(detail::is_compiled_string<S>::value)>
+void print(std::FILE* f, const S& format_str, const Args&... args) {
+  memory_buffer buffer;
+  fmt::format_to(std::back_inserter(buffer), format_str, args...);
+  detail::print(f, {buffer.data(), buffer.size()});
+}
+
+template <typename S, typename... Args,
+          FMT_ENABLE_IF(detail::is_compiled_string<S>::value)>
+void print(const S& format_str, const Args&... args) {
+  print(stdout, format_str, args...);
+}
+
+#if FMT_USE_NONTYPE_TEMPLATE_ARGS
+inline namespace literals {
+template <detail_exported::fixed_string Str> constexpr auto operator""_cf() {
+  using char_t = remove_cvref_t<decltype(Str.data[0])>;
+  return detail::udl_compiled_string<char_t, sizeof(Str.data) / sizeof(char_t),
+                                     Str>();
+}
+}  // namespace literals
+#endif
+
+FMT_END_EXPORT
 FMT_END_NAMESPACE
 
 #endif  // FMT_COMPILE_H_

include/fmt/locale.h

@@ -1,78 +0,0 @@
-// Formatting library for C++ - std::locale support
-//
-// Copyright (c) 2012 - present, Victor Zverovich
-// All rights reserved.
-//
-// For the license information refer to format.h.
-
-#ifndef FMT_LOCALE_H_
-#define FMT_LOCALE_H_
-
-#include <locale>
-
-#include "format.h"
-
-FMT_BEGIN_NAMESPACE
-
-namespace detail {
-template <typename Char>
-typename buffer_context<Char>::iterator vformat_to(
-    const std::locale& loc, buffer<Char>& buf,
-    basic_string_view<Char> format_str,
-    basic_format_args<buffer_context<type_identity_t<Char>>> args) {
-  using af = arg_formatter<typename buffer_context<Char>::iterator, Char>;
-  return vformat_to<af>(std::back_inserter(buf), to_string_view(format_str),
-                        args, detail::locale_ref(loc));
-}
-
-template <typename Char>
-std::basic_string<Char> vformat(
-    const std::locale& loc, basic_string_view<Char> format_str,
-    basic_format_args<buffer_context<type_identity_t<Char>>> args) {
-  basic_memory_buffer<Char> buffer;
-  detail::vformat_to(loc, buffer, format_str, args);
-  return fmt::to_string(buffer);
-}
-}  // namespace detail
-
-template <typename S, typename Char = char_t<S>>
-inline std::basic_string<Char> vformat(
-    const std::locale& loc, const S& format_str,
-    basic_format_args<buffer_context<type_identity_t<Char>>> args) {
-  return detail::vformat(loc, to_string_view(format_str), args);
-}
-
-template <typename S, typename... Args, typename Char = char_t<S>>
-inline std::basic_string<Char> format(const std::locale& loc,
-                                      const S& format_str, Args&&... args) {
-  return detail::vformat(
-      loc, to_string_view(format_str),
-      detail::make_args_checked<Args...>(format_str, args...));
-}
-
-template <typename S, typename OutputIt, typename... Args,
-          typename Char = enable_if_t<
-              detail::is_output_iterator<OutputIt>::value, char_t<S>>>
-inline OutputIt vformat_to(
-    OutputIt out, const std::locale& loc, const S& format_str,
-    format_args_t<type_identity_t<OutputIt>, Char> args) {
-  using af = detail::arg_formatter<OutputIt, Char>;
-  return vformat_to<af>(out, to_string_view(format_str), args,
-                        detail::locale_ref(loc));
-}
-
-template <typename OutputIt, typename S, typename... Args,
-          FMT_ENABLE_IF(detail::is_output_iterator<OutputIt>::value&&
-                            detail::is_string<S>::value)>
-inline OutputIt format_to(OutputIt out, const std::locale& loc,
-                          const S& format_str, Args&&... args) {
-  detail::check_format_string<Args...>(format_str);
-  using context = format_context_t<OutputIt, char_t<S>>;
-  format_arg_store<context, Args...> as{args...};
-  return vformat_to(out, loc, to_string_view(format_str),
-                    basic_format_args<context>(as));
-}
-
-FMT_END_NAMESPACE
-
-#endif  // FMT_LOCALE_H_

include/fmt/os.h

@@ -8,16 +8,10 @@
 #ifndef FMT_OS_H_
 #define FMT_OS_H_
 
-#if defined(__MINGW32__) || defined(__CYGWIN__)
-// Workaround MinGW bug https://sourceforge.net/p/mingw/bugs/2024/.
-#  undef __STRICT_ANSI__
-#endif
-
 #include <cerrno>
-#include <clocale>  // for locale_t
 #include <cstddef>
 #include <cstdio>
-#include <cstdlib>  // for strtod_l
+#include <system_error>  // std::system_error
 
 #if defined __APPLE__ || defined(__FreeBSD__)
 #  include <xlocale.h>  // for LC_NUMERIC_MASK on OS X
@@ -25,16 +19,20 @@
 
 #include "format.h"
 
+#ifndef FMT_USE_FCNTL
 // UWP doesn't provide _pipe.
-#if FMT_HAS_INCLUDE("winapifamily.h")
-#  include <winapifamily.h>
-#endif
-#if FMT_HAS_INCLUDE("fcntl.h") && \
-    (!defined(WINAPI_FAMILY) || (WINAPI_FAMILY == WINAPI_FAMILY_DESKTOP_APP))
-#  include <fcntl.h>  // for O_RDONLY
-#  define FMT_USE_FCNTL 1
-#else
-#  define FMT_USE_FCNTL 0
+#  if FMT_HAS_INCLUDE("winapifamily.h")
+#    include <winapifamily.h>
+#  endif
+#  if (FMT_HAS_INCLUDE(<fcntl.h>) || defined(__APPLE__) || \
+       defined(__linux__)) &&                              \
+      (!defined(WINAPI_FAMILY) ||                          \
+       (WINAPI_FAMILY == WINAPI_FAMILY_DESKTOP_APP))
+#    include <fcntl.h>  // for O_RDONLY
+#    define FMT_USE_FCNTL 1
+#  else
+#    define FMT_USE_FCNTL 0
+#  endif
 #endif
 
 #ifndef FMT_POSIX
@@ -73,6 +71,7 @@
 #define FMT_RETRY(result, expression) FMT_RETRY_VAL(result, expression, -1)
 
 FMT_BEGIN_NAMESPACE
+FMT_BEGIN_EXPORT
 
 /**
   \rst
@@ -121,89 +120,68 @@ template <typename Char> class basic_cstring_view {
 using cstring_view = basic_cstring_view<char>;
 using wcstring_view = basic_cstring_view<wchar_t>;
 
-// An error code.
-class error_code {
- private:
-  int value_;
-
- public:
-  explicit error_code(int value = 0) FMT_NOEXCEPT : value_(value) {}
-
-  int get() const FMT_NOEXCEPT { return value_; }
-};
-
 #ifdef _WIN32
+FMT_API const std::error_category& system_category() noexcept;
+
 namespace detail {
-// A converter from UTF-16 to UTF-8.
-// It is only provided for Windows since other systems support UTF-8 natively.
-class utf16_to_utf8 {
- private:
-  memory_buffer buffer_;
-
- public:
-  utf16_to_utf8() {}
-  FMT_API explicit utf16_to_utf8(wstring_view s);
-  operator string_view() const { return string_view(&buffer_[0], size()); }
-  size_t size() const { return buffer_.size() - 1; }
-  const char* c_str() const { return &buffer_[0]; }
-  std::string str() const { return std::string(&buffer_[0], size()); }
-
-  // Performs conversion returning a system error code instead of
-  // throwing exception on conversion error. This method may still throw
-  // in case of memory allocation error.
-  FMT_API int convert(wstring_view s);
-};
-
 FMT_API void format_windows_error(buffer<char>& out, int error_code,
-                                  string_view message) FMT_NOEXCEPT;
-}  // namespace detail
+                                  const char* message) noexcept;
+}
 
-/** A Windows error. */
-class windows_error : public system_error {
- private:
-  FMT_API void init(int error_code, string_view format_str, format_args args);
+FMT_API std::system_error vwindows_error(int error_code, string_view format_str,
+                                         format_args args);
 
- public:
-  /**
-   \rst
-   Constructs a :class:`fmt::windows_error` object with the description
-   of the form
+/**
+ \rst
+ Constructs a :class:`std::system_error` object with the description
+ of the form
 
-   .. parsed-literal::
-     *<message>*: *<system-message>*
+ .. parsed-literal::
+   *<message>*: *<system-message>*
 
-   where *<message>* is the formatted message and *<system-message>* is the
-   system message corresponding to the error code.
-   *error_code* is a Windows error code as given by ``GetLastError``.
-   If *error_code* is not a valid error code such as -1, the system message
-   will look like "error -1".
+ where *<message>* is the formatted message and *<system-message>* is the
+ system message corresponding to the error code.
+ *error_code* is a Windows error code as given by ``GetLastError``.
+ If *error_code* is not a valid error code such as -1, the system message
+ will look like "error -1".
 
-   **Example**::
+ **Example**::
 
-     // This throws a windows_error with the description
-     //   cannot open file 'madeup': The system cannot find the file specified.
-     // or similar (system message may vary).
-     const char *filename = "madeup";
-     LPOFSTRUCT of = LPOFSTRUCT();
-     HFILE file = OpenFile(filename, &of, OF_READ);
-     if (file == HFILE_ERROR) {
-       throw fmt::windows_error(GetLastError(),
-                                "cannot open file '{}'", filename);
-     }
-   \endrst
-  */
-  template <typename... Args>
-  windows_error(int error_code, string_view message, const Args&... args) {
-    init(error_code, message, make_format_args(args...));
-  }
-};
+   // This throws a system_error with the description
+   //   cannot open file 'madeup': The system cannot find the file specified.
+   // or similar (system message may vary).
+   const char *filename = "madeup";
+   LPOFSTRUCT of = LPOFSTRUCT();
+   HFILE file = OpenFile(filename, &of, OF_READ);
+   if (file == HFILE_ERROR) {
+     throw fmt::windows_error(GetLastError(),
+                              "cannot open file '{}'", filename);
+   }
+ \endrst
+*/
+template <typename... Args>
+std::system_error windows_error(int error_code, string_view message,
+                                const Args&... args) {
+  return vwindows_error(error_code, message, fmt::make_format_args(args...));
+}
 
 // Reports a Windows error without throwing an exception.
 // Can be used to report errors from destructors.
-FMT_API void report_windows_error(int error_code,
-                                  string_view message) FMT_NOEXCEPT;
+FMT_API void report_windows_error(int error_code, const char* message) noexcept;
+#else
+inline const std::error_category& system_category() noexcept {
+  return std::system_category();
+}
 #endif  // _WIN32
 
+// std::system is not available on some platforms such as iOS (#2248).
+#ifdef __OSX__
+template <typename S, typename... Args, typename Char = char_t<S>>
+void say(const S& format_str, Args&&... args) {
+  std::system(format("say \"{}\"", format(format_str, args...)).c_str());
+}
+#endif
+
 // A buffered file.
 class buffered_file {
  private:
@@ -218,13 +196,13 @@ class buffered_file {
   void operator=(const buffered_file&) = delete;
 
   // Constructs a buffered_file object which doesn't represent any file.
-  buffered_file() FMT_NOEXCEPT : file_(nullptr) {}
+  buffered_file() noexcept : file_(nullptr) {}
 
   // Destroys the object closing the file it represents if any.
-  FMT_API ~buffered_file() FMT_NOEXCEPT;
+  FMT_API ~buffered_file() noexcept;
 
  public:
-  buffered_file(buffered_file&& other) FMT_NOEXCEPT : file_(other.file_) {
+  buffered_file(buffered_file&& other) noexcept : file_(other.file_) {
     other.file_ = nullptr;
   }
 
@@ -242,11 +220,9 @@ class buffered_file {
   FMT_API void close();
 
   // Returns the pointer to a FILE object representing this file.
-  FILE* get() const FMT_NOEXCEPT { return file_; }
+  FILE* get() const noexcept { return file_; }
 
-  // We place parentheses around fileno to workaround a bug in some versions
-  // of MinGW that define fileno as a macro.
-  FMT_API int(fileno)() const;
+  FMT_API int descriptor() const;
 
   void vprint(string_view format_str, format_args args) {
     fmt::vprint(file_, format_str, args);
@@ -254,18 +230,18 @@ class buffered_file {
 
   template <typename... Args>
   inline void print(string_view format_str, const Args&... args) {
-    vprint(format_str, make_format_args(args...));
+    vprint(format_str, fmt::make_format_args(args...));
   }
 };
 
 #if FMT_USE_FCNTL
 // A file. Closed file is represented by a file object with descriptor -1.
-// Methods that are not declared with FMT_NOEXCEPT may throw
+// Methods that are not declared with noexcept may throw
 // fmt::system_error in case of failure. Note that some errors such as
 // closing the file multiple times will cause a crash on Windows rather
 // than an exception. You can get standard behavior by overriding the
 // invalid parameter handler with _set_invalid_parameter_handler.
-class file {
+class FMT_API file {
  private:
   int fd_;  // File descriptor.
 
@@ -278,22 +254,25 @@ class file {
     RDONLY = FMT_POSIX(O_RDONLY),  // Open for reading only.
     WRONLY = FMT_POSIX(O_WRONLY),  // Open for writing only.
     RDWR = FMT_POSIX(O_RDWR),      // Open for reading and writing.
-    CREATE = FMT_POSIX(O_CREAT)    // Create if the file doesn't exist.
+    CREATE = FMT_POSIX(O_CREAT),   // Create if the file doesn't exist.
+    APPEND = FMT_POSIX(O_APPEND),  // Open in append mode.
+    TRUNC = FMT_POSIX(O_TRUNC)     // Truncate the content of the file.
   };
 
   // Constructs a file object which doesn't represent any file.
-  file() FMT_NOEXCEPT : fd_(-1) {}
+  file() noexcept : fd_(-1) {}
 
   // Opens a file and constructs a file object representing this file.
-  FMT_API file(cstring_view path, int oflag);
+  file(cstring_view path, int oflag);
 
  public:
   file(const file&) = delete;
   void operator=(const file&) = delete;
 
-  file(file&& other) FMT_NOEXCEPT : fd_(other.fd_) { other.fd_ = -1; }
+  file(file&& other) noexcept : fd_(other.fd_) { other.fd_ = -1; }
 
-  file& operator=(file&& other) FMT_NOEXCEPT {
+  // Move assignment is not noexcept because close may throw.
+  file& operator=(file&& other) {
     close();
     fd_ = other.fd_;
     other.fd_ = -1;
@@ -301,150 +280,172 @@ class file {
   }
 
   // Destroys the object closing the file it represents if any.
-  FMT_API ~file() FMT_NOEXCEPT;
+  ~file() noexcept;
 
   // Returns the file descriptor.
-  int descriptor() const FMT_NOEXCEPT { return fd_; }
+  int descriptor() const noexcept { return fd_; }
 
   // Closes the file.
-  FMT_API void close();
+  void close();
 
   // Returns the file size. The size has signed type for consistency with
   // stat::st_size.
-  FMT_API long long size() const;
+  long long size() const;
 
   // Attempts to read count bytes from the file into the specified buffer.
-  FMT_API size_t read(void* buffer, size_t count);
+  size_t read(void* buffer, size_t count);
 
   // Attempts to write count bytes from the specified buffer to the file.
-  FMT_API size_t write(const void* buffer, size_t count);
+  size_t write(const void* buffer, size_t count);
 
   // Duplicates a file descriptor with the dup function and returns
   // the duplicate as a file object.
-  FMT_API static file dup(int fd);
+  static file dup(int fd);
 
   // Makes fd be the copy of this file descriptor, closing fd first if
   // necessary.
-  FMT_API void dup2(int fd);
+  void dup2(int fd);
 
   // Makes fd be the copy of this file descriptor, closing fd first if
   // necessary.
-  FMT_API void dup2(int fd, error_code& ec) FMT_NOEXCEPT;
+  void dup2(int fd, std::error_code& ec) noexcept;
 
   // Creates a pipe setting up read_end and write_end file objects for reading
   // and writing respectively.
-  FMT_API static void pipe(file& read_end, file& write_end);
+  static void pipe(file& read_end, file& write_end);
 
   // Creates a buffered_file object associated with this file and detaches
   // this file object from the file.
-  FMT_API buffered_file fdopen(const char* mode);
+  buffered_file fdopen(const char* mode);
+
+#  if defined(_WIN32) && !defined(__MINGW32__)
+  // Opens a file and constructs a file object representing this file by
+  // wcstring_view filename. Windows only.
+  static file open_windows_file(wcstring_view path, int oflag);
+#  endif
 };
 
 // Returns the memory page size.
 long getpagesize();
 
-class direct_buffered_file;
+namespace detail {
 
-template <typename S, typename... Args>
-void print(direct_buffered_file& f, const S& format_str,
-           const Args&... args);
+struct buffer_size {
+  buffer_size() = default;
+  size_t value = 0;
+  buffer_size operator=(size_t val) const {
+    auto bs = buffer_size();
+    bs.value = val;
+    return bs;
+  }
+};
 
-// A buffered file with a direct buffer access and no synchronization.
-class direct_buffered_file {
- private:
-  file file_;
+struct ostream_params {
+  int oflag = file::WRONLY | file::CREATE | file::TRUNC;
+  size_t buffer_size = BUFSIZ > 32768 ? BUFSIZ : 32768;
 
-  enum { buffer_size = 4096 };
-  char buffer_[buffer_size];
-  int pos_;
+  ostream_params() {}
 
-  void flush() {
-    if (pos_ == 0) return;
-    file_.write(buffer_, pos_);
-    pos_ = 0;
+  template <typename... T>
+  ostream_params(T... params, int new_oflag) : ostream_params(params...) {
+    oflag = new_oflag;
   }
 
-  int free_capacity() const { return buffer_size - pos_; }
+  template <typename... T>
+  ostream_params(T... params, detail::buffer_size bs)
+      : ostream_params(params...) {
+    this->buffer_size = bs.value;
+  }
+
+// Intel has a bug that results in failure to deduce a constructor
+// for empty parameter packs.
+#  if defined(__INTEL_COMPILER) && __INTEL_COMPILER < 2000
+  ostream_params(int new_oflag) : oflag(new_oflag) {}
+  ostream_params(detail::buffer_size bs) : buffer_size(bs.value) {}
+#  endif
+};
+
+class file_buffer final : public buffer<char> {
+  file file_;
+
+  FMT_API void grow(size_t) override;
 
  public:
-  direct_buffered_file(cstring_view path, int oflag)
-    : file_(path, oflag), pos_(0) {}
+  FMT_API file_buffer(cstring_view path, const ostream_params& params);
+  FMT_API file_buffer(file_buffer&& other);
+  FMT_API ~file_buffer();
 
-  ~direct_buffered_file() {
-    flush();
+  void flush() {
+    if (size() == 0) return;
+    file_.write(data(), size() * sizeof(data()[0]));
+    clear();
   }
 
   void close() {
     flush();
     file_.close();
   }
-
-  template <typename S, typename... Args>
-  friend void print(direct_buffered_file& f, const S& format_str,
-                    const Args&... args) {
-    // We could avoid double buffering.
-    auto buf = fmt::memory_buffer();
-    fmt::format_to(std::back_inserter(buf), format_str, args...);
-    auto remaining_pos = 0;
-    auto remaining_size = buf.size();
-    while (remaining_size > detail::to_unsigned(f.free_capacity())) {
-      auto size = f.free_capacity();
-      memcpy(f.buffer_ + f.pos_, buf.data() + remaining_pos, size);
-      f.pos_ += size;
-      f.flush();
-      remaining_pos += size;
-      remaining_size -= size;
-    }
-    memcpy(f.buffer_ + f.pos_, buf.data() + remaining_pos, remaining_size);
-    f.pos_ += static_cast<int>(remaining_size);
-  }
 };
-#endif  // FMT_USE_FCNTL
 
-#ifdef FMT_LOCALE
-// A "C" numeric locale.
-class locale {
+}  // namespace detail
+
+// Added {} below to work around default constructor error known to
+// occur in Xcode versions 7.2.1 and 8.2.1.
+constexpr detail::buffer_size buffer_size{};
+
+/** A fast output stream which is not thread-safe. */
+class FMT_API ostream {
  private:
-#  ifdef _WIN32
-  using locale_t = _locale_t;
+  FMT_MSC_WARNING(suppress : 4251)
+  detail::file_buffer buffer_;
 
-  static void freelocale(locale_t loc) { _free_locale(loc); }
-
-  static double strtod_l(const char* nptr, char** endptr, _locale_t loc) {
-    return _strtod_l(nptr, endptr, loc);
-  }
-#  endif
-
-  locale_t locale_;
+  ostream(cstring_view path, const detail::ostream_params& params)
+      : buffer_(path, params) {}
 
  public:
-  using type = locale_t;
-  locale(const locale&) = delete;
-  void operator=(const locale&) = delete;
+  ostream(ostream&& other) : buffer_(std::move(other.buffer_)) {}
 
-  locale() {
-#  ifndef _WIN32
-    locale_ = FMT_SYSTEM(newlocale(LC_NUMERIC_MASK, "C", nullptr));
-#  else
-    locale_ = _create_locale(LC_NUMERIC, "C");
-#  endif
-    if (!locale_) FMT_THROW(system_error(errno, "cannot create locale"));
-  }
-  ~locale() { freelocale(locale_); }
+  ~ostream();
 
-  type get() const { return locale_; }
+  void flush() { buffer_.flush(); }
 
-  // Converts string to floating-point number and advances str past the end
-  // of the parsed input.
-  double strtod(const char*& str) const {
-    char* end = nullptr;
-    double result = strtod_l(str, &end, locale_);
-    str = end;
-    return result;
+  template <typename... T>
+  friend ostream output_file(cstring_view path, T... params);
+
+  void close() { buffer_.close(); }
+
+  /**
+    Formats ``args`` according to specifications in ``fmt`` and writes the
+    output to the file.
+   */
+  template <typename... T> void print(format_string<T...> fmt, T&&... args) {
+    vformat_to(detail::buffer_appender<char>(buffer_), fmt,
+               fmt::make_format_args(args...));
   }
 };
-using Locale FMT_DEPRECATED_ALIAS = locale;
-#endif  // FMT_LOCALE
+
+/**
+  \rst
+  Opens a file for writing. Supported parameters passed in *params*:
+
+  * ``<integer>``: Flags passed to `open
+    <https://pubs.opengroup.org/onlinepubs/007904875/functions/open.html>`_
+    (``file::WRONLY | file::CREATE | file::TRUNC`` by default)
+  * ``buffer_size=<integer>``: Output buffer size
+
+  **Example**::
+
+    auto out = fmt::output_file("guide.txt");
+    out.print("Don't {}", "Panic");
+  \endrst
+ */
+template <typename... T>
+inline ostream output_file(cstring_view path, T... params) {
+  return {path, detail::ostream_params(params...)};
+}
+#endif  // FMT_USE_FCNTL
+
+FMT_END_EXPORT
 FMT_END_NAMESPACE
 
 #endif  // FMT_OS_H_

include/fmt/ostream.h

@@ -8,77 +8,70 @@
 #ifndef FMT_OSTREAM_H_
 #define FMT_OSTREAM_H_
 
-#include <ostream>
+#include <fstream>  // std::filebuf
+
+#if defined(_WIN32) && defined(__GLIBCXX__)
+#  include <ext/stdio_filebuf.h>
+#  include <ext/stdio_sync_filebuf.h>
+#elif defined(_WIN32) && defined(_LIBCPP_VERSION)
+#  include <__std_stream>
+#endif
 
 #include "format.h"
 
 FMT_BEGIN_NAMESPACE
 
-template <typename Char> class basic_printf_parse_context;
-template <typename OutputIt, typename Char> class basic_printf_context;
-
 namespace detail {
 
-template <class Char> class formatbuf : public std::basic_streambuf<Char> {
- private:
-  using int_type = typename std::basic_streambuf<Char>::int_type;
-  using traits_type = typename std::basic_streambuf<Char>::traits_type;
-
-  buffer<Char>& buffer_;
-
- public:
-  formatbuf(buffer<Char>& buf) : buffer_(buf) {}
-
- protected:
-  // The put-area is actually always empty. This makes the implementation
-  // simpler and has the advantage that the streambuf and the buffer are always
-  // in sync and sputc never writes into uninitialized memory. The obvious
-  // disadvantage is that each call to sputc always results in a (virtual) call
-  // to overflow. There is no disadvantage here for sputn since this always
-  // results in a call to xsputn.
-
-  int_type overflow(int_type ch = traits_type::eof()) FMT_OVERRIDE {
-    if (!traits_type::eq_int_type(ch, traits_type::eof()))
-      buffer_.push_back(static_cast<Char>(ch));
-    return ch;
-  }
-
-  std::streamsize xsputn(const Char* s, std::streamsize count) FMT_OVERRIDE {
-    buffer_.append(s, s + count);
-    return count;
-  }
+// Generate a unique explicit instantion in every translation unit using a tag
+// type in an anonymous namespace.
+namespace {
+struct file_access_tag {};
+}  // namespace
+template <typename Tag, typename BufType, FILE* BufType::*FileMemberPtr>
+class file_access {
+  friend auto get_file(BufType& obj) -> FILE* { return obj.*FileMemberPtr; }
 };
 
-template <typename Char> struct test_stream : std::basic_ostream<Char> {
- private:
-  // Hide all operator<< from std::basic_ostream<Char>.
-  void_t<> operator<<(null<>);
-  void_t<> operator<<(const Char*);
+#if FMT_MSC_VERSION
+template class file_access<file_access_tag, std::filebuf,
+                           &std::filebuf::_Myfile>;
+auto get_file(std::filebuf&) -> FILE*;
+#elif defined(_WIN32) && defined(_LIBCPP_VERSION)
+template class file_access<file_access_tag, std::__stdoutbuf<char>,
+                           &std::__stdoutbuf<char>::__file_>;
+auto get_file(std::__stdoutbuf<char>&) -> FILE*;
+#endif
 
-  template <typename T, FMT_ENABLE_IF(std::is_convertible<T, int>::value &&
-                                      !std::is_enum<T>::value)>
-  void_t<> operator<<(T);
-};
-
-// Checks if T has a user-defined operator<< (e.g. not a member of
-// std::ostream).
-template <typename T, typename Char> class is_streamable {
- private:
-  template <typename U>
-  static bool_constant<!std::is_same<decltype(std::declval<test_stream<Char>&>()
-                                              << std::declval<U>()),
-                                     void_t<>>::value>
-  test(int);
-
-  template <typename> static std::false_type test(...);
-
-  using result = decltype(test<T>(0));
-
- public:
-  static const bool value = result::value;
-};
+inline bool write_ostream_unicode(std::ostream& os, fmt::string_view data) {
+#if FMT_MSC_VERSION
+  if (auto* buf = dynamic_cast<std::filebuf*>(os.rdbuf()))
+    if (FILE* f = get_file(*buf)) return write_console(f, data);
+#elif defined(_WIN32) && defined(__GLIBCXX__)
+  auto* rdbuf = os.rdbuf();
+  FILE* c_file;
+  if (auto* sfbuf = dynamic_cast<__gnu_cxx::stdio_sync_filebuf<char>*>(rdbuf))
+    c_file = sfbuf->file();
+  else if (auto* fbuf = dynamic_cast<__gnu_cxx::stdio_filebuf<char>*>(rdbuf))
+    c_file = fbuf->file();
+  else
+    return false;
+  if (c_file) return write_console(c_file, data);
+#elif defined(_WIN32) && defined(_LIBCPP_VERSION)
+  if (auto* buf = dynamic_cast<std::__stdoutbuf<char>*>(os.rdbuf()))
+    if (FILE* f = get_file(*buf)) return write_console(f, data);
+#else
+  ignore_unused(os, data);
+#endif
+  return false;
+}
+inline bool write_ostream_unicode(std::wostream&,
+                                  fmt::basic_string_view<wchar_t>) {
+  return false;
+}
 
 // Write the content of buf to os.
+// It is a separate function rather than a part of vprint to simplify testing.
 template <typename Char>
 void write_buffer(std::basic_ostream<Char>& os, buffer<Char>& buf) {
   const Char* buf_data = buf.data();
@@ -96,57 +89,82 @@ void write_buffer(std::basic_ostream<Char>& os, buffer<Char>& buf) {
 template <typename Char, typename T>
 void format_value(buffer<Char>& buf, const T& value,
                   locale_ref loc = locale_ref()) {
-  formatbuf<Char> format_buf(buf);
-  std::basic_ostream<Char> output(&format_buf);
+  auto&& format_buf = formatbuf<std::basic_streambuf<Char>>(buf);
+  auto&& output = std::basic_ostream<Char>(&format_buf);
 #if !defined(FMT_STATIC_THOUSANDS_SEPARATOR)
   if (loc) output.imbue(loc.get<std::locale>());
 #endif
   output << value;
   output.exceptions(std::ios_base::failbit | std::ios_base::badbit);
-  buf.resize(buf.size());
 }
 
-// Formats an object of type T that has an overloaded ostream operator<<.
-template <typename T, typename Char>
-struct fallback_formatter<T, Char, enable_if_t<is_streamable<T, Char>::value>>
-    : private formatter<basic_string_view<Char>, Char> {
-  FMT_CONSTEXPR auto parse(basic_format_parse_context<Char>& ctx)
-      -> decltype(ctx.begin()) {
-    return formatter<basic_string_view<Char>, Char>::parse(ctx);
-  }
-  template <typename ParseCtx,
-            FMT_ENABLE_IF(std::is_same<
-                          ParseCtx, basic_printf_parse_context<Char>>::value)>
-  auto parse(ParseCtx& ctx) -> decltype(ctx.begin()) {
-    return ctx.begin();
-  }
+template <typename T> struct streamed_view { const T& value; };
 
-  template <typename OutputIt>
-  auto format(const T& value, basic_format_context<OutputIt, Char>& ctx)
-      -> OutputIt {
-    basic_memory_buffer<Char> buffer;
-    format_value(buffer, value, ctx.locale());
-    basic_string_view<Char> str(buffer.data(), buffer.size());
-    return formatter<basic_string_view<Char>, Char>::format(str, ctx);
-  }
-  template <typename OutputIt>
-  auto format(const T& value, basic_printf_context<OutputIt, Char>& ctx)
-      -> OutputIt {
-    basic_memory_buffer<Char> buffer;
-    format_value(buffer, value, ctx.locale());
-    return std::copy(buffer.begin(), buffer.end(), ctx.out());
-  }
-};
 }  // namespace detail
 
+// Formats an object of type T that has an overloaded ostream operator<<.
 template <typename Char>
-void vprint(std::basic_ostream<Char>& os, basic_string_view<Char> format_str,
-            basic_format_args<buffer_context<type_identity_t<Char>>> args) {
-  basic_memory_buffer<Char> buffer;
+struct basic_ostream_formatter : formatter<basic_string_view<Char>, Char> {
+  void set_debug_format() = delete;
+
+  template <typename T, typename OutputIt>
+  auto format(const T& value, basic_format_context<OutputIt, Char>& ctx) const
+      -> OutputIt {
+    auto buffer = basic_memory_buffer<Char>();
+    detail::format_value(buffer, value, ctx.locale());
+    return formatter<basic_string_view<Char>, Char>::format(
+        {buffer.data(), buffer.size()}, ctx);
+  }
+};
+
+using ostream_formatter = basic_ostream_formatter<char>;
+
+template <typename T, typename Char>
+struct formatter<detail::streamed_view<T>, Char>
+    : basic_ostream_formatter<Char> {
+  template <typename OutputIt>
+  auto format(detail::streamed_view<T> view,
+              basic_format_context<OutputIt, Char>& ctx) const -> OutputIt {
+    return basic_ostream_formatter<Char>::format(view.value, ctx);
+  }
+};
+
+/**
+  \rst
+  Returns a view that formats `value` via an ostream ``operator<<``.
+
+  **Example**::
+
+    fmt::print("Current thread id: {}\n",
+               fmt::streamed(std::this_thread::get_id()));
+  \endrst
+ */
+template <typename T>
+auto streamed(const T& value) -> detail::streamed_view<T> {
+  return {value};
+}
+
+namespace detail {
+
+inline void vprint_directly(std::ostream& os, string_view format_str,
+                            format_args args) {
+  auto buffer = memory_buffer();
   detail::vformat_to(buffer, format_str, args);
   detail::write_buffer(os, buffer);
 }
 
+}  // namespace detail
+
+FMT_EXPORT template <typename Char>
+void vprint(std::basic_ostream<Char>& os,
+            basic_string_view<type_identity_t<Char>> format_str,
+            basic_format_args<buffer_context<type_identity_t<Char>>> args) {
+  auto buffer = basic_memory_buffer<Char>();
+  detail::vformat_to(buffer, format_str, args);
+  if (detail::write_ostream_unicode(os, {buffer.data(), buffer.size()})) return;
+  detail::write_buffer(os, buffer);
+}
+
 /**
   \rst
   Prints formatted data to the stream *os*.
@@ -156,12 +174,36 @@ void vprint(std::basic_ostream<Char>& os, basic_string_view<Char> format_str,
     fmt::print(cerr, "Don't {}!", "panic");
   \endrst
  */
-template <typename S, typename... Args,
-          typename Char = enable_if_t<detail::is_string<S>::value, char_t<S>>>
-void print(std::basic_ostream<Char>& os, const S& format_str, Args&&... args) {
-  vprint(os, to_string_view(format_str),
-         detail::make_args_checked<Args...>(format_str, args...));
+FMT_EXPORT template <typename... T>
+void print(std::ostream& os, format_string<T...> fmt, T&&... args) {
+  const auto& vargs = fmt::make_format_args(args...);
+  if (detail::is_utf8())
+    vprint(os, fmt, vargs);
+  else
+    detail::vprint_directly(os, fmt, vargs);
 }
+
+FMT_EXPORT
+template <typename... Args>
+void print(std::wostream& os,
+           basic_format_string<wchar_t, type_identity_t<Args>...> fmt,
+           Args&&... args) {
+  vprint(os, fmt, fmt::make_format_args<buffer_context<wchar_t>>(args...));
+}
+
+FMT_EXPORT template <typename... T>
+void println(std::ostream& os, format_string<T...> fmt, T&&... args) {
+  fmt::print(os, "{}\n", fmt::format(fmt, std::forward<T>(args)...));
+}
+
+FMT_EXPORT
+template <typename... Args>
+void println(std::wostream& os,
+             basic_format_string<wchar_t, type_identity_t<Args>...> fmt,
+             Args&&... args) {
+  print(os, L"{}\n", fmt::format(fmt, std::forward<Args>(args)...));
+}
+
 FMT_END_NAMESPACE
 
 #endif  // FMT_OSTREAM_H_

include/fmt/posix.h

@@ -1,2 +0,0 @@
-#include "os.h"
-#warning "fmt/posix.h is deprecated; use fmt/os.h instead"

include/fmt/printf.h

@@ -11,55 +11,91 @@
 #include <algorithm>  // std::max
 #include <limits>     // std::numeric_limits
 
-#include "ostream.h"
+#include "format.h"
 
 FMT_BEGIN_NAMESPACE
+FMT_BEGIN_EXPORT
+
+template <typename T> struct printf_formatter { printf_formatter() = delete; };
+
+template <typename Char> class basic_printf_context {
+ private:
+  detail::buffer_appender<Char> out_;
+  basic_format_args<basic_printf_context> args_;
+
+ public:
+  using char_type = Char;
+  using parse_context_type = basic_format_parse_context<Char>;
+  template <typename T> using formatter_type = printf_formatter<T>;
+
+  /**
+    \rst
+    Constructs a ``printf_context`` object. References to the arguments are
+    stored in the context object so make sure they have appropriate lifetimes.
+    \endrst
+   */
+  basic_printf_context(detail::buffer_appender<Char> out,
+                       basic_format_args<basic_printf_context> args)
+      : out_(out), args_(args) {}
+
+  auto out() -> detail::buffer_appender<Char> { return out_; }
+  void advance_to(detail::buffer_appender<Char>) {}
+
+  auto locale() -> detail::locale_ref { return {}; }
+
+  auto arg(int id) const -> basic_format_arg<basic_printf_context> {
+    return args_.get(id);
+  }
+
+  FMT_CONSTEXPR void on_error(const char* message) {
+    detail::error_handler().on_error(message);
+  }
+};
+
 namespace detail {
 
 // Checks if a value fits in int - used to avoid warnings about comparing
 // signed and unsigned integers.
 template <bool IsSigned> struct int_checker {
-  template <typename T> static bool fits_in_int(T value) {
+  template <typename T> static auto fits_in_int(T value) -> bool {
     unsigned max = max_value<int>();
     return value <= max;
   }
-  static bool fits_in_int(bool) { return true; }
+  static auto fits_in_int(bool) -> bool { return true; }
 };
 
 template <> struct int_checker<true> {
-  template <typename T> static bool fits_in_int(T value) {
+  template <typename T> static auto fits_in_int(T value) -> bool {
     return value >= (std::numeric_limits<int>::min)() &&
            value <= max_value<int>();
   }
-  static bool fits_in_int(int) { return true; }
+  static auto fits_in_int(int) -> bool { return true; }
 };
 
-class printf_precision_handler {
- public:
+struct printf_precision_handler {
   template <typename T, FMT_ENABLE_IF(std::is_integral<T>::value)>
-  int operator()(T value) {
+  auto operator()(T value) -> int {
     if (!int_checker<std::numeric_limits<T>::is_signed>::fits_in_int(value))
-      FMT_THROW(format_error("number is too big"));
+      throw_format_error("number is too big");
     return (std::max)(static_cast<int>(value), 0);
   }
 
   template <typename T, FMT_ENABLE_IF(!std::is_integral<T>::value)>
-  int operator()(T) {
-    FMT_THROW(format_error("precision is not integer"));
+  auto operator()(T) -> int {
+    throw_format_error("precision is not integer");
     return 0;
   }
 };
 
 // An argument visitor that returns true iff arg is a zero integer.
-class is_zero_int {
- public:
+struct is_zero_int {
   template <typename T, FMT_ENABLE_IF(std::is_integral<T>::value)>
-  bool operator()(T value) {
+  auto operator()(T value) -> bool {
     return value == 0;
   }
 
   template <typename T, FMT_ENABLE_IF(!std::is_integral<T>::value)>
-  bool operator()(T) {
+  auto operator()(T) -> bool {
     return false;
   }
 };
@@ -90,22 +126,23 @@ template <typename T, typename Context> class arg_converter {
     if (const_check(sizeof(target_type) <= sizeof(int))) {
       // Extra casts are used to silence warnings.
       if (is_signed) {
-        arg_ = detail::make_arg<Context>(
-            static_cast<int>(static_cast<target_type>(value)));
+        auto n = static_cast<int>(static_cast<target_type>(value));
+        arg_ = detail::make_arg<Context>(n);
       } else {
         using unsigned_type = typename make_unsigned_or_bool<target_type>::type;
-        arg_ = detail::make_arg<Context>(
-            static_cast<unsigned>(static_cast<unsigned_type>(value)));
+        auto n = static_cast<unsigned>(static_cast<unsigned_type>(value));
+        arg_ = detail::make_arg<Context>(n);
       }
     } else {
       if (is_signed) {
         // glibc's printf doesn't sign extend arguments of smaller types:
         //   std::printf("%lld", -42);  // prints "4294967254"
         // but we don't have to do the same because it's a UB.
-        arg_ = detail::make_arg<Context>(static_cast<long long>(value));
+        auto n = static_cast<long long>(value);
+        arg_ = detail::make_arg<Context>(n);
       } else {
-        arg_ = detail::make_arg<Context>(
-            static_cast<typename make_unsigned_or_bool<U>::type>(value));
+        auto n = static_cast<typename make_unsigned_or_bool<U>::type>(value);
+        arg_ = detail::make_arg<Context>(n);
       }
     }
   }
@@ -133,8 +170,8 @@ template <typename Context> class char_converter {
 
   template <typename T, FMT_ENABLE_IF(std::is_integral<T>::value)>
   void operator()(T value) {
-    arg_ = detail::make_arg<Context>(
-        static_cast<typename Context::char_type>(value));
+    auto c = static_cast<typename Context::char_type>(value);
+    arg_ = detail::make_arg<Context>(c);
   }
 
   template <typename T, FMT_ENABLE_IF(!std::is_integral<T>::value)>
@@ -144,254 +181,131 @@ template <typename Context> class char_converter {
 // An argument visitor that return a pointer to a C string if argument is a
 // string or null otherwise.
 template <typename Char> struct get_cstring {
-  template <typename T> const Char* operator()(T) { return nullptr; }
-  const Char* operator()(const Char* s) { return s; }
+  template <typename T> auto operator()(T) -> const Char* { return nullptr; }
+  auto operator()(const Char* s) -> const Char* { return s; }
 };
 
 // Checks if an argument is a valid printf width specifier and sets
 // left alignment if it is negative.
 template <typename Char> class printf_width_handler {
  private:
-  using format_specs = basic_format_specs<Char>;
-
-  format_specs& specs_;
+  format_specs<Char>& specs_;
 
  public:
-  explicit printf_width_handler(format_specs& specs) : specs_(specs) {}
+  explicit printf_width_handler(format_specs<Char>& specs) : specs_(specs) {}
 
   template <typename T, FMT_ENABLE_IF(std::is_integral<T>::value)>
-  unsigned operator()(T value) {
+  auto operator()(T value) -> unsigned {
     auto width = static_cast<uint32_or_64_or_128_t<T>>(value);
     if (detail::is_negative(value)) {
       specs_.align = align::left;
       width = 0 - width;
     }
     unsigned int_max = max_value<int>();
-    if (width > int_max) FMT_THROW(format_error("number is too big"));
+    if (width > int_max) throw_format_error("number is too big");
     return static_cast<unsigned>(width);
   }
 
   template <typename T, FMT_ENABLE_IF(!std::is_integral<T>::value)>
-  unsigned operator()(T) {
-    FMT_THROW(format_error("width is not integer"));
+  auto operator()(T) -> unsigned {
+    throw_format_error("width is not integer");
     return 0;
   }
 };
 
-template <typename Char, typename Context>
-void vprintf(buffer<Char>& buf, basic_string_view<Char> format,
-             basic_format_args<Context> args) {
-  Context(std::back_inserter(buf), format, args).format();
-}
-}  // namespace detail
-
-// For printing into memory_buffer.
-template <typename Char, typename Context>
-FMT_DEPRECATED void printf(detail::buffer<Char>& buf,
-                           basic_string_view<Char> format,
-                           basic_format_args<Context> args) {
-  return detail::vprintf(buf, format, args);
-}
-using detail::vprintf;
-
+// Workaround for a bug with the XL compiler when initializing
+// printf_arg_formatter's base class.
 template <typename Char>
-class basic_printf_parse_context : public basic_format_parse_context<Char> {
-  using basic_format_parse_context<Char>::basic_format_parse_context;
-};
-template <typename OutputIt, typename Char> class basic_printf_context;
-
-/**
-  \rst
-  The ``printf`` argument formatter.
-  \endrst
- */
-template <typename OutputIt, typename Char>
-class printf_arg_formatter : public detail::arg_formatter_base<OutputIt, Char> {
- public:
-  using iterator = OutputIt;
+auto make_arg_formatter(buffer_appender<Char> iter, format_specs<Char>& s)
+    -> arg_formatter<Char> {
+  return {iter, s, locale_ref()};
+}
 
+// The ``printf`` argument formatter.
+template <typename Char>
+class printf_arg_formatter : public arg_formatter<Char> {
  private:
-  using char_type = Char;
-  using base = detail::arg_formatter_base<OutputIt, Char>;
-  using context_type = basic_printf_context<OutputIt, Char>;
+  using base = arg_formatter<Char>;
+  using context_type = basic_printf_context<Char>;
 
   context_type& context_;
 
-  void write_null_pointer(char) {
-    this->specs()->type = 0;
-    this->write("(nil)");
-  }
-
-  void write_null_pointer(wchar_t) {
-    this->specs()->type = 0;
-    this->write(L"(nil)");
+  void write_null_pointer(bool is_string = false) {
+    auto s = this->specs;
+    s.type = presentation_type::none;
+    write_bytes(this->out, is_string ? "(null)" : "(nil)", s);
   }
 
  public:
-  using format_specs = typename base::format_specs;
+  printf_arg_formatter(buffer_appender<Char> iter, format_specs<Char>& s,
+                       context_type& ctx)
+      : base(make_arg_formatter(iter, s)), context_(ctx) {}
 
-  /**
-    \rst
-    Constructs an argument formatter object.
-    *buffer* is a reference to the output buffer and *specs* contains format
-    specifier information for standard argument types.
-    \endrst
-   */
-  printf_arg_formatter(iterator iter, format_specs& specs, context_type& ctx)
-      : base(iter, &specs, detail::locale_ref()), context_(ctx) {}
+  void operator()(monostate value) { base::operator()(value); }
 
-  template <typename T, FMT_ENABLE_IF(fmt::detail::is_integral<T>::value)>
-  iterator operator()(T value) {
-    // MSVC2013 fails to compile separate overloads for bool and char_type so
-    // use std::is_same instead.
-    if (std::is_same<T, bool>::value) {
-      format_specs& fmt_specs = *this->specs();
-      if (fmt_specs.type != 's') return base::operator()(value ? 1 : 0);
-      fmt_specs.type = 0;
-      this->write(value != 0);
-    } else if (std::is_same<T, char_type>::value) {
-      format_specs& fmt_specs = *this->specs();
-      if (fmt_specs.type && fmt_specs.type != 'c')
-        return (*this)(static_cast<int>(value));
-      fmt_specs.sign = sign::none;
-      fmt_specs.alt = false;
-      fmt_specs.fill[0] = ' ';  // Ignore '0' flag for char types.
-      // align::numeric needs to be overwritten here since the '0' flag is
-      // ignored for non-numeric types
-      if (fmt_specs.align == align::none || fmt_specs.align == align::numeric)
-        fmt_specs.align = align::right;
-      return base::operator()(value);
-    } else {
-      return base::operator()(value);
+  template <typename T, FMT_ENABLE_IF(detail::is_integral<T>::value)>
+  void operator()(T value) {
+    // MSVC2013 fails to compile separate overloads for bool and Char so use
+    // std::is_same instead.
+    if (!std::is_same<T, Char>::value) {
+      base::operator()(value);
+      return;
     }
-    return this->out();
+    format_specs<Char> fmt_specs = this->specs;
+    if (fmt_specs.type != presentation_type::none &&
+        fmt_specs.type != presentation_type::chr) {
+      return (*this)(static_cast<int>(value));
+    }
+    fmt_specs.sign = sign::none;
+    fmt_specs.alt = false;
+    fmt_specs.fill[0] = ' ';  // Ignore '0' flag for char types.
+    // align::numeric needs to be overwritten here since the '0' flag is
+    // ignored for non-numeric types
+    if (fmt_specs.align == align::none || fmt_specs.align == align::numeric)
+      fmt_specs.align = align::right;
+    write<Char>(this->out, static_cast<Char>(value), fmt_specs);
   }
 
   template <typename T, FMT_ENABLE_IF(std::is_floating_point<T>::value)>
-  iterator operator()(T value) {
-    return base::operator()(value);
+  void operator()(T value) {
+    base::operator()(value);
   }
 
   /** Formats a null-terminated C string. */
-  iterator operator()(const char* value) {
+  void operator()(const char* value) {
     if (value)
       base::operator()(value);
-    else if (this->specs()->type == 'p')
-      write_null_pointer(char_type());
     else
-      this->write("(null)");
-    return this->out();
+      write_null_pointer(this->specs.type != presentation_type::pointer);
   }
 
   /** Formats a null-terminated wide C string. */
-  iterator operator()(const wchar_t* value) {
+  void operator()(const wchar_t* value) {
     if (value)
       base::operator()(value);
-    else if (this->specs()->type == 'p')
-      write_null_pointer(char_type());
     else
-      this->write(L"(null)");
-    return this->out();
+      write_null_pointer(this->specs.type != presentation_type::pointer);
   }
 
-  iterator operator()(basic_string_view<char_type> value) {
-    return base::operator()(value);
-  }
-
-  iterator operator()(monostate value) { return base::operator()(value); }
+  void operator()(basic_string_view<Char> value) { base::operator()(value); }
 
   /** Formats a pointer. */
-  iterator operator()(const void* value) {
-    if (value) return base::operator()(value);
-    this->specs()->type = 0;
-    write_null_pointer(char_type());
-    return this->out();
+  void operator()(const void* value) {
+    if (value)
+      base::operator()(value);
+    else
+      write_null_pointer();
   }
 
   /** Formats an argument of a custom (user-defined) type. */
-  iterator operator()(typename basic_format_arg<context_type>::handle handle) {
-    handle.format(context_.parse_context(), context_);
-    return this->out();
+  void operator()(typename basic_format_arg<context_type>::handle handle) {
+    auto parse_ctx = basic_format_parse_context<Char>({});
+    handle.format(parse_ctx, context_);
   }
 };
 
-template <typename T> struct printf_formatter {
-  printf_formatter() = delete;
-
-  template <typename ParseContext>
-  auto parse(ParseContext& ctx) -> decltype(ctx.begin()) {
-    return ctx.begin();
-  }
-
-  template <typename FormatContext>
-  auto format(const T& value, FormatContext& ctx) -> decltype(ctx.out()) {
-    detail::format_value(detail::get_container(ctx.out()), value);
-    return ctx.out();
-  }
-};
-
-/**
- This template formats data and writes the output through an output iterator.
- */
-template <typename OutputIt, typename Char> class basic_printf_context {
- public:
-  /** The character type for the output. */
-  using char_type = Char;
-  using iterator = OutputIt;
-  using format_arg = basic_format_arg<basic_printf_context>;
-  using parse_context_type = basic_printf_parse_context<Char>;
-  template <typename T> using formatter_type = printf_formatter<T>;
-
- private:
-  using format_specs = basic_format_specs<char_type>;
-
-  OutputIt out_;
-  basic_format_args<basic_printf_context> args_;
-  parse_context_type parse_ctx_;
-
-  static void parse_flags(format_specs& specs, const Char*& it,
-                          const Char* end);
-
-  // Returns the argument with specified index or, if arg_index is -1, the next
-  // argument.
-  format_arg get_arg(int arg_index = -1);
-
-  // Parses argument index, flags and width and returns the argument index.
-  int parse_header(const Char*& it, const Char* end, format_specs& specs);
-
- public:
-  /**
-   \rst
-   Constructs a ``printf_context`` object. References to the arguments are
-   stored in the context object so make sure they have appropriate lifetimes.
-   \endrst
-   */
-  basic_printf_context(OutputIt out, basic_string_view<char_type> format_str,
-                       basic_format_args<basic_printf_context> args)
-      : out_(out), args_(args), parse_ctx_(format_str) {}
-
-  OutputIt out() { return out_; }
-  void advance_to(OutputIt it) { out_ = it; }
-
-  detail::locale_ref locale() { return {}; }
-
-  format_arg arg(int id) const { return args_.get(id); }
-
-  parse_context_type& parse_context() { return parse_ctx_; }
-
-  FMT_CONSTEXPR void on_error(const char* message) {
-    parse_ctx_.on_error(message);
-  }
-
-  /** Formats stored arguments and writes the output to the range. */
-  template <typename ArgFormatter = printf_arg_formatter<OutputIt, Char>>
-  OutputIt format();
-};
-
-template <typename OutputIt, typename Char>
-void basic_printf_context<OutputIt, Char>::parse_flags(format_specs& specs,
-                                                       const Char*& it,
-                                                       const Char* end) {
+template <typename Char>
+void parse_flags(format_specs<Char>& specs, const Char*& it, const Char* end) {
   for (; it != end; ++it) {
     switch (*it) {
     case '-':
@@ -404,9 +318,7 @@ void basic_printf_context<OutputIt, Char>::parse_flags(format_specs& specs,
       specs.fill[0] = '0';
       break;
     case ' ':
-      if (specs.sign != sign::plus) {
-        specs.sign = sign::space;
-      }
+      if (specs.sign != sign::plus) specs.sign = sign::space;
       break;
     case '#':
       specs.alt = true;
@@ -417,35 +329,24 @@ void basic_printf_context<OutputIt, Char>::parse_flags(format_specs& specs,
   }
 }
 
-template <typename OutputIt, typename Char>
-typename basic_printf_context<OutputIt, Char>::format_arg
-basic_printf_context<OutputIt, Char>::get_arg(int arg_index) {
-  if (arg_index < 0)
-    arg_index = parse_ctx_.next_arg_id();
-  else
-    parse_ctx_.check_arg_id(--arg_index);
-  return detail::get_arg(*this, arg_index);
-}
-
-template <typename OutputIt, typename Char>
-int basic_printf_context<OutputIt, Char>::parse_header(const Char*& it,
-                                                       const Char* end,
-                                                       format_specs& specs) {
+template <typename Char, typename GetArg>
+auto parse_header(const Char*& it, const Char* end, format_specs<Char>& specs,
+                  GetArg get_arg) -> int {
   int arg_index = -1;
-  char_type c = *it;
+  Char c = *it;
   if (c >= '0' && c <= '9') {
     // Parse an argument index (if followed by '$') or a width possibly
     // preceded with '0' flag(s).
-    detail::error_handler eh;
-    int value = parse_nonnegative_int(it, end, eh);
+    int value = parse_nonnegative_int(it, end, -1);
     if (it != end && *it == '$') {  // value is an argument index
       ++it;
-      arg_index = value;
+      arg_index = value != -1 ? value : max_value<int>();
     } else {
       if (c == '0') specs.fill[0] = '0';
       if (value != 0) {
         // Nonzero value means that we parsed width and don't need to
         // parse it or flags again, so return now.
+        if (value == -1) throw_format_error("number is too big");
         specs.width = value;
         return arg_index;
       }
@@ -455,73 +356,129 @@ int basic_printf_context<OutputIt, Char>::parse_header(const Char*& it,
   // Parse width.
   if (it != end) {
     if (*it >= '0' && *it <= '9') {
-      detail::error_handler eh;
-      specs.width = parse_nonnegative_int(it, end, eh);
+      specs.width = parse_nonnegative_int(it, end, -1);
+      if (specs.width == -1) throw_format_error("number is too big");
     } else if (*it == '*') {
       ++it;
       specs.width = static_cast<int>(visit_format_arg(
-          detail::printf_width_handler<char_type>(specs), get_arg()));
+          detail::printf_width_handler<Char>(specs), get_arg(-1)));
     }
   }
   return arg_index;
 }
 
-template <typename OutputIt, typename Char>
-template <typename ArgFormatter>
-OutputIt basic_printf_context<OutputIt, Char>::format() {
-  auto out = this->out();
-  const Char* start = parse_ctx_.begin();
-  const Char* end = parse_ctx_.end();
+inline auto parse_printf_presentation_type(char c, type t)
+    -> presentation_type {
+  using pt = presentation_type;
+  constexpr auto integral_set = sint_set | uint_set | bool_set | char_set;
+  switch (c) {
+  case 'd':
+    return in(t, integral_set) ? pt::dec : pt::none;
+  case 'o':
+    return in(t, integral_set) ? pt::oct : pt::none;
+  case 'x':
+    return in(t, integral_set) ? pt::hex_lower : pt::none;
+  case 'X':
+    return in(t, integral_set) ? pt::hex_upper : pt::none;
+  case 'a':
+    return in(t, float_set) ? pt::hexfloat_lower : pt::none;
+  case 'A':
+    return in(t, float_set) ? pt::hexfloat_upper : pt::none;
+  case 'e':
+    return in(t, float_set) ? pt::exp_lower : pt::none;
+  case 'E':
+    return in(t, float_set) ? pt::exp_upper : pt::none;
+  case 'f':
+    return in(t, float_set) ? pt::fixed_lower : pt::none;
+  case 'F':
+    return in(t, float_set) ? pt::fixed_upper : pt::none;
+  case 'g':
+    return in(t, float_set) ? pt::general_lower : pt::none;
+  case 'G':
+    return in(t, float_set) ? pt::general_upper : pt::none;
+  case 'c':
+    return in(t, integral_set) ? pt::chr : pt::none;
+  case 's':
+    return in(t, string_set | cstring_set) ? pt::string : pt::none;
+  case 'p':
+    return in(t, pointer_set | cstring_set) ? pt::pointer : pt::none;
+  default:
+    return pt::none;
+  }
+}
+
+template <typename Char, typename Context>
+void vprintf(buffer<Char>& buf, basic_string_view<Char> format,
+             basic_format_args<Context> args) {
+  using iterator = buffer_appender<Char>;
+  auto out = iterator(buf);
+  auto context = basic_printf_context<Char>(out, args);
+  auto parse_ctx = basic_format_parse_context<Char>(format);
+
+  // Returns the argument with specified index or, if arg_index is -1, the next
+  // argument.
+  auto get_arg = [&](int arg_index) {
+    if (arg_index < 0)
+      arg_index = parse_ctx.next_arg_id();
+    else
+      parse_ctx.check_arg_id(--arg_index);
+    return detail::get_arg(context, arg_index);
+  };
+
+  const Char* start = parse_ctx.begin();
+  const Char* end = parse_ctx.end();
   auto it = start;
   while (it != end) {
-    char_type c = *it++;
-    if (c != '%') continue;
+    if (!find<false, Char>(it, end, '%', it)) {
+      it = end;  // find leaves it == nullptr if it doesn't find '%'.
+      break;
+    }
+    Char c = *it++;
     if (it != end && *it == c) {
-      out = std::copy(start, it, out);
+      write(out, basic_string_view<Char>(start, to_unsigned(it - start)));
       start = ++it;
       continue;
     }
-    out = std::copy(start, it - 1, out);
+    write(out, basic_string_view<Char>(start, to_unsigned(it - 1 - start)));
 
-    format_specs specs;
+    auto specs = format_specs<Char>();
     specs.align = align::right;
 
     // Parse argument index, flags and width.
-    int arg_index = parse_header(it, end, specs);
-    if (arg_index == 0) on_error("argument not found");
+    int arg_index = parse_header(it, end, specs, get_arg);
+    if (arg_index == 0) throw_format_error("argument not found");
 
     // Parse precision.
     if (it != end && *it == '.') {
       ++it;
       c = it != end ? *it : 0;
       if ('0' <= c && c <= '9') {
-        detail::error_handler eh;
-        specs.precision = parse_nonnegative_int(it, end, eh);
+        specs.precision = parse_nonnegative_int(it, end, 0);
       } else if (c == '*') {
         ++it;
         specs.precision = static_cast<int>(
-            visit_format_arg(detail::printf_precision_handler(), get_arg()));
+            visit_format_arg(printf_precision_handler(), get_arg(-1)));
       } else {
         specs.precision = 0;
       }
     }
 
-    format_arg arg = get_arg(arg_index);
+    auto arg = get_arg(arg_index);
     // For d, i, o, u, x, and X conversion specifiers, if a precision is
     // specified, the '0' flag is ignored
-    if (specs.precision >= 0 && arg.is_integral())
-      specs.fill[0] =
-          ' ';  // Ignore '0' flag for non-numeric types or if '-' present.
-    if (specs.precision >= 0 && arg.type() == detail::type::cstring_type) {
-      auto str = visit_format_arg(detail::get_cstring<Char>(), arg);
+    if (specs.precision >= 0 && arg.is_integral()) {
+      // Ignore '0' for non-numeric types or if '-' present.
+      specs.fill[0] = ' ';
+    }
+    if (specs.precision >= 0 && arg.type() == type::cstring_type) {
+      auto str = visit_format_arg(get_cstring<Char>(), arg);
       auto str_end = str + specs.precision;
       auto nul = std::find(str, str_end, Char());
-      arg = detail::make_arg<basic_printf_context>(basic_string_view<Char>(
-          str,
-          detail::to_unsigned(nul != str_end ? nul - str : specs.precision)));
+      auto sv = basic_string_view<Char>(
+          str, to_unsigned(nul != str_end ? nul - str : specs.precision));
+      arg = make_arg<basic_printf_context<Char>>(sv);
     }
-    if (specs.alt && visit_format_arg(detail::is_zero_int(), arg))
-      specs.alt = false;
+    if (specs.alt && visit_format_arg(is_zero_int(), arg)) specs.alt = false;
     if (specs.fill[0] == '0') {
       if (arg.is_arithmetic() && specs.align != align::left)
         specs.align = align::numeric;
@@ -532,8 +489,7 @@ OutputIt basic_printf_context<OutputIt, Char>::format() {
 
     // Parse length and convert the argument to the required type.
     c = it != end ? *it++ : 0;
-    char_type t = it != end ? *it : 0;
-    using detail::convert_arg;
+    Char t = it != end ? *it : 0;
     switch (c) {
     case 'h':
       if (t == 'h') {
@@ -572,36 +528,35 @@ OutputIt basic_printf_context<OutputIt, Char>::format() {
     }
 
     // Parse type.
-    if (it == end) FMT_THROW(format_error("invalid format string"));
-    specs.type = static_cast<char>(*it++);
+    if (it == end) throw_format_error("invalid format string");
+    char type = static_cast<char>(*it++);
     if (arg.is_integral()) {
       // Normalize type.
-      switch (specs.type) {
+      switch (type) {
       case 'i':
       case 'u':
-        specs.type = 'd';
+        type = 'd';
         break;
       case 'c':
-        visit_format_arg(detail::char_converter<basic_printf_context>(arg),
-                         arg);
+        visit_format_arg(char_converter<basic_printf_context<Char>>(arg), arg);
         break;
       }
     }
+    specs.type = parse_printf_presentation_type(type, arg.type());
+    if (specs.type == presentation_type::none)
+      throw_format_error("invalid format specifier");
 
     start = it;
 
     // Format argument.
-    out = visit_format_arg(ArgFormatter(out, specs, *this), arg);
+    visit_format_arg(printf_arg_formatter<Char>(out, specs, context), arg);
   }
-  return std::copy(start, it, out);
+  write(out, basic_string_view<Char>(start, to_unsigned(it - start)));
 }
+}  // namespace detail
 
-template <typename Char>
-using basic_printf_context_t =
-    basic_printf_context<std::back_insert_iterator<detail::buffer<Char>>, Char>;
-
-using printf_context = basic_printf_context_t<char>;
-using wprintf_context = basic_printf_context_t<wchar_t>;
+using printf_context = basic_printf_context<char>;
+using wprintf_context = basic_printf_context<wchar_t>;
 
 using printf_args = basic_format_args<printf_context>;
 using wprintf_args = basic_format_args<wprintf_context>;
@@ -612,31 +567,27 @@ using wprintf_args = basic_format_args<wprintf_context>;
   arguments and can be implicitly converted to `~fmt::printf_args`.
   \endrst
  */
-template <typename... Args>
-inline format_arg_store<printf_context, Args...> make_printf_args(
-    const Args&... args) {
+template <typename... T>
+inline auto make_printf_args(const T&... args)
+    -> format_arg_store<printf_context, T...> {
   return {args...};
 }
 
-/**
-  \rst
-  Constructs an `~fmt::format_arg_store` object that contains references to
-  arguments and can be implicitly converted to `~fmt::wprintf_args`.
-  \endrst
- */
-template <typename... Args>
-inline format_arg_store<wprintf_context, Args...> make_wprintf_args(
-    const Args&... args) {
+// DEPRECATED!
+template <typename... T>
+inline auto make_wprintf_args(const T&... args)
+    -> format_arg_store<wprintf_context, T...> {
   return {args...};
 }
 
-template <typename S, typename Char = char_t<S>>
-inline std::basic_string<Char> vsprintf(
-    const S& format,
-    basic_format_args<basic_printf_context_t<type_identity_t<Char>>> args) {
-  basic_memory_buffer<Char> buffer;
-  vprintf(buffer, to_string_view(format), args);
-  return to_string(buffer);
+template <typename Char>
+inline auto vsprintf(
+    basic_string_view<Char> fmt,
+    basic_format_args<basic_printf_context<type_identity_t<Char>>> args)
+    -> std::basic_string<Char> {
+  auto buf = basic_memory_buffer<Char>();
+  detail::vprintf(buf, fmt, args);
+  return to_string(buf);
 }
 
 /**
@@ -648,21 +599,22 @@ inline std::basic_string<Char> vsprintf(
     std::string message = fmt::sprintf("The answer is %d", 42);
   \endrst
 */
-template <typename S, typename... Args,
+template <typename S, typename... T,
           typename Char = enable_if_t<detail::is_string<S>::value, char_t<S>>>
-inline std::basic_string<Char> sprintf(const S& format, const Args&... args) {
-  using context = basic_printf_context_t<Char>;
-  return vsprintf(to_string_view(format), make_format_args<context>(args...));
+inline auto sprintf(const S& fmt, const T&... args) -> std::basic_string<Char> {
+  return vsprintf(detail::to_string_view(fmt),
+                  fmt::make_format_args<basic_printf_context<Char>>(args...));
 }
 
-template <typename S, typename Char = char_t<S>>
-inline int vfprintf(
-    std::FILE* f, const S& format,
-    basic_format_args<basic_printf_context_t<type_identity_t<Char>>> args) {
-  basic_memory_buffer<Char> buffer;
-  vprintf(buffer, to_string_view(format), args);
-  size_t size = buffer.size();
-  return std::fwrite(buffer.data(), sizeof(Char), size, f) < size
+template <typename Char>
+inline auto vfprintf(
+    std::FILE* f, basic_string_view<Char> fmt,
+    basic_format_args<basic_printf_context<type_identity_t<Char>>> args)
+    -> int {
+  auto buf = basic_memory_buffer<Char>();
+  detail::vprintf(buf, fmt, args);
+  size_t size = buf.size();
+  return std::fwrite(buf.data(), sizeof(Char), size, f) < size
              ? -1
              : static_cast<int>(size);
 }
@@ -676,19 +628,18 @@ inline int vfprintf(
     fmt::fprintf(stderr, "Don't %s!", "panic");
   \endrst
  */
-template <typename S, typename... Args,
-          typename Char = enable_if_t<detail::is_string<S>::value, char_t<S>>>
-inline int fprintf(std::FILE* f, const S& format, const Args&... args) {
-  using context = basic_printf_context_t<Char>;
-  return vfprintf(f, to_string_view(format),
-                  make_format_args<context>(args...));
+template <typename S, typename... T, typename Char = char_t<S>>
+inline auto fprintf(std::FILE* f, const S& fmt, const T&... args) -> int {
+  return vfprintf(f, detail::to_string_view(fmt),
+                  fmt::make_format_args<basic_printf_context<Char>>(args...));
 }
 
-template <typename S, typename Char = char_t<S>>
-inline int vprintf(
-    const S& format,
-    basic_format_args<basic_printf_context_t<type_identity_t<Char>>> args) {
-  return vfprintf(stdout, to_string_view(format), args);
+template <typename Char>
+FMT_DEPRECATED inline auto vprintf(
+    basic_string_view<Char> fmt,
+    basic_format_args<basic_printf_context<type_identity_t<Char>>> args)
+    -> int {
+  return vfprintf(stdout, fmt, args);
 }
 
 /**
@@ -700,52 +651,17 @@ inline int vprintf(
     fmt::printf("Elapsed time: %.2f seconds", 1.23);
   \endrst
  */
-template <typename S, typename... Args,
-          FMT_ENABLE_IF(detail::is_string<S>::value)>
-inline int printf(const S& format_str, const Args&... args) {
-  using context = basic_printf_context_t<char_t<S>>;
-  return vprintf(to_string_view(format_str),
-                 make_format_args<context>(args...));
+template <typename... T>
+inline auto printf(string_view fmt, const T&... args) -> int {
+  return vfprintf(stdout, fmt, make_printf_args(args...));
+}
+template <typename... T>
+FMT_DEPRECATED inline auto printf(basic_string_view<wchar_t> fmt,
+                                  const T&... args) -> int {
+  return vfprintf(stdout, fmt, make_wprintf_args(args...));
 }
 
-template <typename S, typename Char = char_t<S>>
-inline int vfprintf(
-    std::basic_ostream<Char>& os, const S& format,
-    basic_format_args<basic_printf_context_t<type_identity_t<Char>>> args) {
-  basic_memory_buffer<Char> buffer;
-  vprintf(buffer, to_string_view(format), args);
-  detail::write_buffer(os, buffer);
-  return static_cast<int>(buffer.size());
-}
-
-/** Formats arguments and writes the output to the range. */
-template <typename ArgFormatter, typename Char,
-          typename Context =
-              basic_printf_context<typename ArgFormatter::iterator, Char>>
-typename ArgFormatter::iterator vprintf(
-    detail::buffer<Char>& out, basic_string_view<Char> format_str,
-    basic_format_args<type_identity_t<Context>> args) {
-  typename ArgFormatter::iterator iter(out);
-  Context(iter, format_str, args).template format<ArgFormatter>();
-  return iter;
-}
-
-/**
-  \rst
-  Prints formatted data to the stream *os*.
-
-  **Example**::
-
-    fmt::fprintf(cerr, "Don't %s!", "panic");
-  \endrst
- */
-template <typename S, typename... Args, typename Char = char_t<S>>
-inline int fprintf(std::basic_ostream<Char>& os, const S& format_str,
-                   const Args&... args) {
-  using context = basic_printf_context_t<Char>;
-  return vfprintf(os, to_string_view(format_str),
-                  make_format_args<context>(args...));
-}
+FMT_END_EXPORT
 FMT_END_NAMESPACE
 
 #endif  // FMT_PRINTF_H_

include/fmt/ranges.h

@@ -13,109 +13,172 @@
 #define FMT_RANGES_H_
 
 #include <initializer_list>
+#include <tuple>
 #include <type_traits>
 
 #include "format.h"
 
-// output only up to N items from the range.
-#ifndef FMT_RANGE_OUTPUT_LENGTH_LIMIT
-#  define FMT_RANGE_OUTPUT_LENGTH_LIMIT 256
-#endif
-
 FMT_BEGIN_NAMESPACE
 
-template <typename Char> struct formatting_base {
-  template <typename ParseContext>
-  FMT_CONSTEXPR auto parse(ParseContext& ctx) -> decltype(ctx.begin()) {
-    return ctx.begin();
-  }
-};
-
-template <typename Char, typename Enable = void>
-struct formatting_range : formatting_base<Char> {
-  static FMT_CONSTEXPR_DECL const size_t range_length_limit =
-      FMT_RANGE_OUTPUT_LENGTH_LIMIT;  // output only up to N items from the
-                                      // range.
-  Char prefix;
-  Char delimiter;
-  Char postfix;
-  formatting_range() : prefix('{'), delimiter(','), postfix('}') {}
-  static FMT_CONSTEXPR_DECL const bool add_delimiter_spaces = true;
-  static FMT_CONSTEXPR_DECL const bool add_prepostfix_space = false;
-};
-
-template <typename Char, typename Enable = void>
-struct formatting_tuple : formatting_base<Char> {
-  Char prefix;
-  Char delimiter;
-  Char postfix;
-  formatting_tuple() : prefix('('), delimiter(','), postfix(')') {}
-  static FMT_CONSTEXPR_DECL const bool add_delimiter_spaces = true;
-  static FMT_CONSTEXPR_DECL const bool add_prepostfix_space = false;
-};
-
 namespace detail {
 
-template <typename RangeT, typename OutputIterator>
-OutputIterator copy(const RangeT& range, OutputIterator out) {
+template <typename Range, typename OutputIt>
+auto copy(const Range& range, OutputIt out) -> OutputIt {
   for (auto it = range.begin(), end = range.end(); it != end; ++it)
     *out++ = *it;
   return out;
 }
 
-template <typename OutputIterator>
-OutputIterator copy(const char* str, OutputIterator out) {
+template <typename OutputIt>
+auto copy(const char* str, OutputIt out) -> OutputIt {
   while (*str) *out++ = *str++;
   return out;
 }
 
-template <typename OutputIterator>
-OutputIterator copy(char ch, OutputIterator out) {
+template <typename OutputIt> auto copy(char ch, OutputIt out) -> OutputIt {
   *out++ = ch;
   return out;
 }
 
-/// Return true value if T has std::string interface, like std::string_view.
-template <typename T> class is_like_std_string {
+template <typename OutputIt> auto copy(wchar_t ch, OutputIt out) -> OutputIt {
+  *out++ = ch;
+  return out;
+}
+
+// Returns true if T has a std::string-like interface, like std::string_view.
+template <typename T> class is_std_string_like {
   template <typename U>
   static auto check(U* p)
       -> decltype((void)p->find('a'), p->length(), (void)p->data(), int());
   template <typename> static void check(...);
 
  public:
-  static FMT_CONSTEXPR_DECL const bool value =
-      is_string<T>::value || !std::is_void<decltype(check<T>(nullptr))>::value;
+  static constexpr const bool value =
+      is_string<T>::value ||
+      std::is_convertible<T, std_string_view<char>>::value ||
+      !std::is_void<decltype(check<T>(nullptr))>::value;
 };
 
 template <typename Char>
-struct is_like_std_string<fmt::basic_string_view<Char>> : std::true_type {};
+struct is_std_string_like<fmt::basic_string_view<Char>> : std::true_type {};
+
+template <typename T> class is_map {
+  template <typename U> static auto check(U*) -> typename U::mapped_type;
+  template <typename> static void check(...);
+
+ public:
+#ifdef FMT_FORMAT_MAP_AS_LIST  // DEPRECATED!
+  static constexpr const bool value = false;
+#else
+  static constexpr const bool value =
+      !std::is_void<decltype(check<T>(nullptr))>::value;
+#endif
+};
+
+template <typename T> class is_set {
+  template <typename U> static auto check(U*) -> typename U::key_type;
+  template <typename> static void check(...);
+
+ public:
+#ifdef FMT_FORMAT_SET_AS_LIST  // DEPRECATED!
+  static constexpr const bool value = false;
+#else
+  static constexpr const bool value =
+      !std::is_void<decltype(check<T>(nullptr))>::value && !is_map<T>::value;
+#endif
+};
 
 template <typename... Ts> struct conditional_helper {};
 
 template <typename T, typename _ = void> struct is_range_ : std::false_type {};
 
-#if !FMT_MSC_VER || FMT_MSC_VER > 1800
+#if !FMT_MSC_VERSION || FMT_MSC_VERSION > 1800
+
+#  define FMT_DECLTYPE_RETURN(val)  \
+    ->decltype(val) { return val; } \
+    static_assert(                  \
+        true, "")  // This makes it so that a semicolon is required after the
+                   // macro, which helps clang-format handle the formatting.
+
+// C array overload
+template <typename T, std::size_t N>
+auto range_begin(const T (&arr)[N]) -> const T* {
+  return arr;
+}
+template <typename T, std::size_t N>
+auto range_end(const T (&arr)[N]) -> const T* {
+  return arr + N;
+}
+
+template <typename T, typename Enable = void>
+struct has_member_fn_begin_end_t : std::false_type {};
+
 template <typename T>
-struct is_range_<
-    T, conditional_t<false,
-                     conditional_helper<decltype(std::declval<T>().begin()),
-                                        decltype(std::declval<T>().end())>,
-                     void>> : std::true_type {};
+struct has_member_fn_begin_end_t<T, void_t<decltype(std::declval<T>().begin()),
+                                           decltype(std::declval<T>().end())>>
+    : std::true_type {};
+
+// Member function overload
+template <typename T>
+auto range_begin(T&& rng) FMT_DECLTYPE_RETURN(static_cast<T&&>(rng).begin());
+template <typename T>
+auto range_end(T&& rng) FMT_DECLTYPE_RETURN(static_cast<T&&>(rng).end());
+
+// ADL overload. Only participates in overload resolution if member functions
+// are not found.
+template <typename T>
+auto range_begin(T&& rng)
+    -> enable_if_t<!has_member_fn_begin_end_t<T&&>::value,
+                   decltype(begin(static_cast<T&&>(rng)))> {
+  return begin(static_cast<T&&>(rng));
+}
+template <typename T>
+auto range_end(T&& rng) -> enable_if_t<!has_member_fn_begin_end_t<T&&>::value,
+                                       decltype(end(static_cast<T&&>(rng)))> {
+  return end(static_cast<T&&>(rng));
+}
+
+template <typename T, typename Enable = void>
+struct has_const_begin_end : std::false_type {};
+template <typename T, typename Enable = void>
+struct has_mutable_begin_end : std::false_type {};
+
+template <typename T>
+struct has_const_begin_end<
+    T,
+    void_t<
+        decltype(detail::range_begin(std::declval<const remove_cvref_t<T>&>())),
+        decltype(detail::range_end(std::declval<const remove_cvref_t<T>&>()))>>
+    : std::true_type {};
+
+template <typename T>
+struct has_mutable_begin_end<
+    T, void_t<decltype(detail::range_begin(std::declval<T>())),
+              decltype(detail::range_end(std::declval<T>())),
+              // the extra int here is because older versions of MSVC don't
+              // SFINAE properly unless there are distinct types
+              int>> : std::true_type {};
+
+template <typename T>
+struct is_range_<T, void>
+    : std::integral_constant<bool, (has_const_begin_end<T>::value ||
+                                    has_mutable_begin_end<T>::value)> {};
+#  undef FMT_DECLTYPE_RETURN
 #endif
 
-/// tuple_size and tuple_element check.
+// tuple_size and tuple_element check.
 template <typename T> class is_tuple_like_ {
   template <typename U>
   static auto check(U* p) -> decltype(std::tuple_size<U>::value, int());
   template <typename> static void check(...);
 
  public:
-  static FMT_CONSTEXPR_DECL const bool value =
+  static constexpr const bool value =
       !std::is_void<decltype(check<T>(nullptr))>::value;
 };
 
 // Check for integer_sequence
-#if defined(__cpp_lib_integer_sequence) || FMT_MSC_VER >= 1900
+#if defined(__cpp_lib_integer_sequence) || FMT_MSC_VERSION >= 1900
 template <typename T, T... N>
 using integer_sequence = std::integer_sequence<T, N...>;
 template <size_t... N> using index_sequence = std::index_sequence<N...>;
@@ -138,203 +201,493 @@ template <size_t N>
 using make_index_sequence = make_integer_sequence<size_t, N>;
 #endif
 
-template <class Tuple, class F, size_t... Is>
-void for_each(index_sequence<Is...>, Tuple&& tup, F&& f) FMT_NOEXCEPT {
+template <typename T>
+using tuple_index_sequence = make_index_sequence<std::tuple_size<T>::value>;
+
+template <typename T, typename C, bool = is_tuple_like_<T>::value>
+class is_tuple_formattable_ {
+ public:
+  static constexpr const bool value = false;
+};
+template <typename T, typename C> class is_tuple_formattable_<T, C, true> {
+  template <std::size_t... Is>
+  static std::true_type check2(index_sequence<Is...>,
+                               integer_sequence<bool, (Is == Is)...>);
+  static std::false_type check2(...);
+  template <std::size_t... Is>
+  static decltype(check2(
+      index_sequence<Is...>{},
+      integer_sequence<
+          bool, (is_formattable<typename std::tuple_element<Is, T>::type,
+                                C>::value)...>{})) check(index_sequence<Is...>);
+
+ public:
+  static constexpr const bool value =
+      decltype(check(tuple_index_sequence<T>{}))::value;
+};
+
+template <typename Tuple, typename F, size_t... Is>
+FMT_CONSTEXPR void for_each(index_sequence<Is...>, Tuple&& t, F&& f) {
   using std::get;
-  // using free function get<I>(T) now.
-  const int _[] = {0, ((void)f(get<Is>(tup)), 0)...};
-  (void)_;  // blocks warnings
+  // Using a free function get<Is>(Tuple) now.
+  const int unused[] = {0, ((void)f(get<Is>(t)), 0)...};
+  ignore_unused(unused);
 }
 
-template <class T>
-FMT_CONSTEXPR make_index_sequence<std::tuple_size<T>::value> get_indexes(
-    T const&) {
-  return {};
+template <typename Tuple, typename F>
+FMT_CONSTEXPR void for_each(Tuple&& t, F&& f) {
+  for_each(tuple_index_sequence<remove_cvref_t<Tuple>>(),
+           std::forward<Tuple>(t), std::forward<F>(f));
 }
 
-template <class Tuple, class F> void for_each(Tuple&& tup, F&& f) {
-  const auto indexes = get_indexes(tup);
-  for_each(indexes, std::forward<Tuple>(tup), std::forward<F>(f));
+template <typename Tuple1, typename Tuple2, typename F, size_t... Is>
+void for_each2(index_sequence<Is...>, Tuple1&& t1, Tuple2&& t2, F&& f) {
+  using std::get;
+  const int unused[] = {0, ((void)f(get<Is>(t1), get<Is>(t2)), 0)...};
+  ignore_unused(unused);
 }
 
-template <typename Arg, FMT_ENABLE_IF(!is_like_std_string<
-                                      typename std::decay<Arg>::type>::value)>
-FMT_CONSTEXPR const char* format_str_quoted(bool add_space, const Arg&) {
-  return add_space ? " {}" : "{}";
+template <typename Tuple1, typename Tuple2, typename F>
+void for_each2(Tuple1&& t1, Tuple2&& t2, F&& f) {
+  for_each2(tuple_index_sequence<remove_cvref_t<Tuple1>>(),
+            std::forward<Tuple1>(t1), std::forward<Tuple2>(t2),
+            std::forward<F>(f));
 }
 
-template <typename Arg, FMT_ENABLE_IF(is_like_std_string<
-                                      typename std::decay<Arg>::type>::value)>
-FMT_CONSTEXPR const char* format_str_quoted(bool add_space, const Arg&) {
-  return add_space ? " \"{}\"" : "\"{}\"";
-}
+namespace tuple {
+// Workaround a bug in MSVC 2019 (v140).
+template <typename Char, typename... T>
+using result_t = std::tuple<formatter<remove_cvref_t<T>, Char>...>;
 
-FMT_CONSTEXPR const char* format_str_quoted(bool add_space, const char*) {
-  return add_space ? " \"{}\"" : "\"{}\"";
-}
-FMT_CONSTEXPR const wchar_t* format_str_quoted(bool add_space, const wchar_t*) {
-  return add_space ? L" \"{}\"" : L"\"{}\"";
-}
+using std::get;
+template <typename Tuple, typename Char, std::size_t... Is>
+auto get_formatters(index_sequence<Is...>)
+    -> result_t<Char, decltype(get<Is>(std::declval<Tuple>()))...>;
+}  // namespace tuple
 
-FMT_CONSTEXPR const char* format_str_quoted(bool add_space, const char) {
-  return add_space ? " '{}'" : "'{}'";
-}
-FMT_CONSTEXPR const wchar_t* format_str_quoted(bool add_space, const wchar_t) {
-  return add_space ? L" '{}'" : L"'{}'";
+#if FMT_MSC_VERSION && FMT_MSC_VERSION < 1920
+// Older MSVC doesn't get the reference type correctly for arrays.
+template <typename R> struct range_reference_type_impl {
+  using type = decltype(*detail::range_begin(std::declval<R&>()));
+};
+
+template <typename T, std::size_t N> struct range_reference_type_impl<T[N]> {
+  using type = T&;
+};
+
+template <typename T>
+using range_reference_type = typename range_reference_type_impl<T>::type;
+#else
+template <typename Range>
+using range_reference_type =
+    decltype(*detail::range_begin(std::declval<Range&>()));
+#endif
+
+// We don't use the Range's value_type for anything, but we do need the Range's
+// reference type, with cv-ref stripped.
+template <typename Range>
+using uncvref_type = remove_cvref_t<range_reference_type<Range>>;
+
+template <typename Formatter>
+FMT_CONSTEXPR auto maybe_set_debug_format(Formatter& f, bool set)
+    -> decltype(f.set_debug_format(set)) {
+  f.set_debug_format(set);
 }
+template <typename Formatter>
+FMT_CONSTEXPR void maybe_set_debug_format(Formatter&, ...) {}
+
+// These are not generic lambdas for compatibility with C++11.
+template <typename ParseContext> struct parse_empty_specs {
+  template <typename Formatter> FMT_CONSTEXPR void operator()(Formatter& f) {
+    f.parse(ctx);
+    detail::maybe_set_debug_format(f, true);
+  }
+  ParseContext& ctx;
+};
+template <typename FormatContext> struct format_tuple_element {
+  using char_type = typename FormatContext::char_type;
+
+  template <typename T>
+  void operator()(const formatter<T, char_type>& f, const T& v) {
+    if (i > 0)
+      ctx.advance_to(detail::copy_str<char_type>(separator, ctx.out()));
+    ctx.advance_to(f.format(v, ctx));
+    ++i;
+  }
+
+  int i;
+  FormatContext& ctx;
+  basic_string_view<char_type> separator;
+};
 
 }  // namespace detail
 
 template <typename T> struct is_tuple_like {
-  static FMT_CONSTEXPR_DECL const bool value =
+  static constexpr const bool value =
       detail::is_tuple_like_<T>::value && !detail::is_range_<T>::value;
 };
 
-template <typename TupleT, typename Char>
-struct formatter<TupleT, Char, enable_if_t<fmt::is_tuple_like<TupleT>::value>> {
- private:
-  // C++11 generic lambda for format()
-  template <typename FormatContext> struct format_each {
-    template <typename T> void operator()(const T& v) {
-      if (i > 0) {
-        if (formatting.add_prepostfix_space) {
-          *out++ = ' ';
-        }
-        out = detail::copy(formatting.delimiter, out);
-      }
-      out = format_to(out,
-                      detail::format_str_quoted(
-                          (formatting.add_delimiter_spaces && i > 0), v),
-                      v);
-      ++i;
-    }
+template <typename T, typename C> struct is_tuple_formattable {
+  static constexpr const bool value =
+      detail::is_tuple_formattable_<T, C>::value;
+};
 
-    formatting_tuple<Char>& formatting;
-    size_t& i;
-    typename std::add_lvalue_reference<decltype(
-        std::declval<FormatContext>().out())>::type out;
-  };
+template <typename Tuple, typename Char>
+struct formatter<Tuple, Char,
+                 enable_if_t<fmt::is_tuple_like<Tuple>::value &&
+                             fmt::is_tuple_formattable<Tuple, Char>::value>> {
+ private:
+  decltype(detail::tuple::get_formatters<Tuple, Char>(
+      detail::tuple_index_sequence<Tuple>())) formatters_;
+
+  basic_string_view<Char> separator_ = detail::string_literal<Char, ',', ' '>{};
+  basic_string_view<Char> opening_bracket_ =
+      detail::string_literal<Char, '('>{};
+  basic_string_view<Char> closing_bracket_ =
+      detail::string_literal<Char, ')'>{};
 
  public:
-  formatting_tuple<Char> formatting;
+  FMT_CONSTEXPR formatter() {}
+
+  FMT_CONSTEXPR void set_separator(basic_string_view<Char> sep) {
+    separator_ = sep;
+  }
+
+  FMT_CONSTEXPR void set_brackets(basic_string_view<Char> open,
+                                  basic_string_view<Char> close) {
+    opening_bracket_ = open;
+    closing_bracket_ = close;
+  }
 
   template <typename ParseContext>
   FMT_CONSTEXPR auto parse(ParseContext& ctx) -> decltype(ctx.begin()) {
-    return formatting.parse(ctx);
+    auto it = ctx.begin();
+    if (it != ctx.end() && *it != '}')
+      FMT_THROW(format_error("invalid format specifier"));
+    detail::for_each(formatters_, detail::parse_empty_specs<ParseContext>{ctx});
+    return it;
   }
 
-  template <typename FormatContext = format_context>
-  auto format(const TupleT& values, FormatContext& ctx) -> decltype(ctx.out()) {
-    auto out = ctx.out();
-    size_t i = 0;
-    detail::copy(formatting.prefix, out);
-
-    detail::for_each(values, format_each<FormatContext>{formatting, i, out});
-    if (formatting.add_prepostfix_space) {
-      *out++ = ' ';
-    }
-    detail::copy(formatting.postfix, out);
-
-    return ctx.out();
+  template <typename FormatContext>
+  auto format(const Tuple& value, FormatContext& ctx) const
+      -> decltype(ctx.out()) {
+    ctx.advance_to(detail::copy_str<Char>(opening_bracket_, ctx.out()));
+    detail::for_each2(
+        formatters_, value,
+        detail::format_tuple_element<FormatContext>{0, ctx, separator_});
+    return detail::copy_str<Char>(closing_bracket_, ctx.out());
   }
 };
 
 template <typename T, typename Char> struct is_range {
-  static FMT_CONSTEXPR_DECL const bool value =
-      detail::is_range_<T>::value && !detail::is_like_std_string<T>::value &&
+  static constexpr const bool value =
+      detail::is_range_<T>::value && !detail::is_std_string_like<T>::value &&
       !std::is_convertible<T, std::basic_string<Char>>::value &&
-      !std::is_constructible<detail::std_string_view<Char>, T>::value;
+      !std::is_convertible<T, detail::std_string_view<Char>>::value;
 };
 
-template <typename RangeT, typename Char>
-struct formatter<RangeT, Char,
-                 enable_if_t<fmt::is_range<RangeT, Char>::value>> {
-  formatting_range<Char> formatting;
+namespace detail {
+template <typename Context> struct range_mapper {
+  using mapper = arg_mapper<Context>;
+
+  template <typename T,
+            FMT_ENABLE_IF(has_formatter<remove_cvref_t<T>, Context>::value)>
+  static auto map(T&& value) -> T&& {
+    return static_cast<T&&>(value);
+  }
+  template <typename T,
+            FMT_ENABLE_IF(!has_formatter<remove_cvref_t<T>, Context>::value)>
+  static auto map(T&& value)
+      -> decltype(mapper().map(static_cast<T&&>(value))) {
+    return mapper().map(static_cast<T&&>(value));
+  }
+};
+
+template <typename Char, typename Element>
+using range_formatter_type =
+    formatter<remove_cvref_t<decltype(range_mapper<buffer_context<Char>>{}.map(
+                  std::declval<Element>()))>,
+              Char>;
+
+template <typename R>
+using maybe_const_range =
+    conditional_t<has_const_begin_end<R>::value, const R, R>;
+
+// Workaround a bug in MSVC 2015 and earlier.
+#if !FMT_MSC_VERSION || FMT_MSC_VERSION >= 1910
+template <typename R, typename Char>
+struct is_formattable_delayed
+    : is_formattable<uncvref_type<maybe_const_range<R>>, Char> {};
+#endif
+}  // namespace detail
+
+template <typename T, typename Char, typename Enable = void>
+struct range_formatter;
+
+template <typename T, typename Char>
+struct range_formatter<
+    T, Char,
+    enable_if_t<conjunction<std::is_same<T, remove_cvref_t<T>>,
+                            is_formattable<T, Char>>::value>> {
+ private:
+  detail::range_formatter_type<Char, T> underlying_;
+  basic_string_view<Char> separator_ = detail::string_literal<Char, ',', ' '>{};
+  basic_string_view<Char> opening_bracket_ =
+      detail::string_literal<Char, '['>{};
+  basic_string_view<Char> closing_bracket_ =
+      detail::string_literal<Char, ']'>{};
+
+ public:
+  FMT_CONSTEXPR range_formatter() {}
+
+  FMT_CONSTEXPR auto underlying() -> detail::range_formatter_type<Char, T>& {
+    return underlying_;
+  }
+
+  FMT_CONSTEXPR void set_separator(basic_string_view<Char> sep) {
+    separator_ = sep;
+  }
+
+  FMT_CONSTEXPR void set_brackets(basic_string_view<Char> open,
+                                  basic_string_view<Char> close) {
+    opening_bracket_ = open;
+    closing_bracket_ = close;
+  }
 
   template <typename ParseContext>
   FMT_CONSTEXPR auto parse(ParseContext& ctx) -> decltype(ctx.begin()) {
-    return formatting.parse(ctx);
+    auto it = ctx.begin();
+    auto end = ctx.end();
+
+    if (it != end && *it == 'n') {
+      set_brackets({}, {});
+      ++it;
+    }
+
+    if (it != end && *it != '}') {
+      if (*it != ':') FMT_THROW(format_error("invalid format specifier"));
+      ++it;
+    } else {
+      detail::maybe_set_debug_format(underlying_, true);
+    }
+
+    ctx.advance_to(it);
+    return underlying_.parse(ctx);
   }
 
-  template <typename FormatContext>
-  typename FormatContext::iterator format(const RangeT& values,
-                                          FormatContext& ctx) {
-    auto out = detail::copy(formatting.prefix, ctx.out());
-    size_t i = 0;
-    auto it = values.begin();
-    auto end = values.end();
+  template <typename R, typename FormatContext>
+  auto format(R&& range, FormatContext& ctx) const -> decltype(ctx.out()) {
+    detail::range_mapper<buffer_context<Char>> mapper;
+    auto out = ctx.out();
+    out = detail::copy_str<Char>(opening_bracket_, out);
+    int i = 0;
+    auto it = detail::range_begin(range);
+    auto end = detail::range_end(range);
     for (; it != end; ++it) {
-      if (i > 0) {
-        if (formatting.add_prepostfix_space) *out++ = ' ';
-        out = detail::copy(formatting.delimiter, out);
-      }
-      out = format_to(out,
-                      detail::format_str_quoted(
-                          (formatting.add_delimiter_spaces && i > 0), *it),
-                      *it);
-      if (++i > formatting.range_length_limit) {
-        out = format_to(out, " ... <other elements>");
-        break;
-      }
+      if (i > 0) out = detail::copy_str<Char>(separator_, out);
+      ctx.advance_to(out);
+      out = underlying_.format(mapper.map(*it), ctx);
+      ++i;
     }
-    if (formatting.add_prepostfix_space) *out++ = ' ';
-    return detail::copy(formatting.postfix, out);
+    out = detail::copy_str<Char>(closing_bracket_, out);
+    return out;
   }
 };
 
-template <typename Char, typename... T> struct tuple_arg_join : detail::view {
+enum class range_format { disabled, map, set, sequence, string, debug_string };
+
+namespace detail {
+template <typename T>
+struct range_format_kind_
+    : std::integral_constant<range_format,
+                             std::is_same<uncvref_type<T>, T>::value
+                                 ? range_format::disabled
+                             : is_map<T>::value ? range_format::map
+                             : is_set<T>::value ? range_format::set
+                                                : range_format::sequence> {};
+
+template <range_format K, typename R, typename Char, typename Enable = void>
+struct range_default_formatter;
+
+template <range_format K>
+using range_format_constant = std::integral_constant<range_format, K>;
+
+template <range_format K, typename R, typename Char>
+struct range_default_formatter<
+    K, R, Char,
+    enable_if_t<(K == range_format::sequence || K == range_format::map ||
+                 K == range_format::set)>> {
+  using range_type = detail::maybe_const_range<R>;
+  range_formatter<detail::uncvref_type<range_type>, Char> underlying_;
+
+  FMT_CONSTEXPR range_default_formatter() { init(range_format_constant<K>()); }
+
+  FMT_CONSTEXPR void init(range_format_constant<range_format::set>) {
+    underlying_.set_brackets(detail::string_literal<Char, '{'>{},
+                             detail::string_literal<Char, '}'>{});
+  }
+
+  FMT_CONSTEXPR void init(range_format_constant<range_format::map>) {
+    underlying_.set_brackets(detail::string_literal<Char, '{'>{},
+                             detail::string_literal<Char, '}'>{});
+    underlying_.underlying().set_brackets({}, {});
+    underlying_.underlying().set_separator(
+        detail::string_literal<Char, ':', ' '>{});
+  }
+
+  FMT_CONSTEXPR void init(range_format_constant<range_format::sequence>) {}
+
+  template <typename ParseContext>
+  FMT_CONSTEXPR auto parse(ParseContext& ctx) -> decltype(ctx.begin()) {
+    return underlying_.parse(ctx);
+  }
+
+  template <typename FormatContext>
+  auto format(range_type& range, FormatContext& ctx) const
+      -> decltype(ctx.out()) {
+    return underlying_.format(range, ctx);
+  }
+};
+}  // namespace detail
+
+template <typename T, typename Char, typename Enable = void>
+struct range_format_kind
+    : conditional_t<
+          is_range<T, Char>::value, detail::range_format_kind_<T>,
+          std::integral_constant<range_format, range_format::disabled>> {};
+
+template <typename R, typename Char>
+struct formatter<
+    R, Char,
+    enable_if_t<conjunction<bool_constant<range_format_kind<R, Char>::value !=
+                                          range_format::disabled>
+// Workaround a bug in MSVC 2015 and earlier.
+#if !FMT_MSC_VERSION || FMT_MSC_VERSION >= 1910
+                            ,
+                            detail::is_formattable_delayed<R, Char>
+#endif
+                            >::value>>
+    : detail::range_default_formatter<range_format_kind<R, Char>::value, R,
+                                      Char> {
+};
+
+template <typename Char, typename... T> struct tuple_join_view : detail::view {
   const std::tuple<T...>& tuple;
   basic_string_view<Char> sep;
 
-  tuple_arg_join(const std::tuple<T...>& t, basic_string_view<Char> s)
-      : tuple{t}, sep{s} {}
+  tuple_join_view(const std::tuple<T...>& t, basic_string_view<Char> s)
+      : tuple(t), sep{s} {}
 };
 
+// Define FMT_TUPLE_JOIN_SPECIFIERS to enable experimental format specifiers
+// support in tuple_join. It is disabled by default because of issues with
+// the dynamic width and precision.
+#ifndef FMT_TUPLE_JOIN_SPECIFIERS
+#  define FMT_TUPLE_JOIN_SPECIFIERS 0
+#endif
+
 template <typename Char, typename... T>
-struct formatter<tuple_arg_join<Char, T...>, Char> {
+struct formatter<tuple_join_view<Char, T...>, Char> {
   template <typename ParseContext>
   FMT_CONSTEXPR auto parse(ParseContext& ctx) -> decltype(ctx.begin()) {
-    return ctx.begin();
+    return do_parse(ctx, std::integral_constant<size_t, sizeof...(T)>());
   }
 
   template <typename FormatContext>
-  typename FormatContext::iterator format(
-      const tuple_arg_join<Char, T...>& value, FormatContext& ctx) {
-    return format(value, ctx, detail::make_index_sequence<sizeof...(T)>{});
+  auto format(const tuple_join_view<Char, T...>& value,
+              FormatContext& ctx) const -> typename FormatContext::iterator {
+    return do_format(value, ctx,
+                     std::integral_constant<size_t, sizeof...(T)>());
   }
 
  private:
-  template <typename FormatContext, size_t... N>
-  typename FormatContext::iterator format(
-      const tuple_arg_join<Char, T...>& value, FormatContext& ctx,
-      detail::index_sequence<N...>) {
-    return format_args(value, ctx, std::get<N>(value.tuple)...);
+  std::tuple<formatter<typename std::decay<T>::type, Char>...> formatters_;
+
+  template <typename ParseContext>
+  FMT_CONSTEXPR auto do_parse(ParseContext& ctx,
+                              std::integral_constant<size_t, 0>)
+      -> decltype(ctx.begin()) {
+    return ctx.begin();
+  }
+
+  template <typename ParseContext, size_t N>
+  FMT_CONSTEXPR auto do_parse(ParseContext& ctx,
+                              std::integral_constant<size_t, N>)
+      -> decltype(ctx.begin()) {
+    auto end = ctx.begin();
+#if FMT_TUPLE_JOIN_SPECIFIERS
+    end = std::get<sizeof...(T) - N>(formatters_).parse(ctx);
+    if (N > 1) {
+      auto end1 = do_parse(ctx, std::integral_constant<size_t, N - 1>());
+      if (end != end1)
+        FMT_THROW(format_error("incompatible format specs for tuple elements"));
+    }
+#endif
+    return end;
   }
 
   template <typename FormatContext>
-  typename FormatContext::iterator format_args(
-      const tuple_arg_join<Char, T...>&, FormatContext& ctx) {
-    // NOTE: for compilers that support C++17, this empty function instantiation
-    // can be replaced with a constexpr branch in the variadic overload.
+  auto do_format(const tuple_join_view<Char, T...>&, FormatContext& ctx,
+                 std::integral_constant<size_t, 0>) const ->
+      typename FormatContext::iterator {
     return ctx.out();
   }
 
-  template <typename FormatContext, typename Arg, typename... Args>
-  typename FormatContext::iterator format_args(
-      const tuple_arg_join<Char, T...>& value, FormatContext& ctx,
-      const Arg& arg, const Args&... args) {
-    using base = formatter<typename std::decay<Arg>::type, Char>;
-    auto out = ctx.out();
-    out = base{}.format(arg, ctx);
-    if (sizeof...(Args) > 0) {
+  template <typename FormatContext, size_t N>
+  auto do_format(const tuple_join_view<Char, T...>& value, FormatContext& ctx,
+                 std::integral_constant<size_t, N>) const ->
+      typename FormatContext::iterator {
+    auto out = std::get<sizeof...(T) - N>(formatters_)
+                   .format(std::get<sizeof...(T) - N>(value.tuple), ctx);
+    if (N > 1) {
       out = std::copy(value.sep.begin(), value.sep.end(), out);
       ctx.advance_to(out);
-      return format_args(value, ctx, args...);
+      return do_format(value, ctx, std::integral_constant<size_t, N - 1>());
     }
     return out;
   }
 };
 
+namespace detail {
+// Check if T has an interface like a container adaptor (e.g. std::stack,
+// std::queue, std::priority_queue).
+template <typename T> class is_container_adaptor_like {
+  template <typename U> static auto check(U* p) -> typename U::container_type;
+  template <typename> static void check(...);
+
+ public:
+  static constexpr const bool value =
+      !std::is_void<decltype(check<T>(nullptr))>::value;
+};
+
+template <typename Container> struct all {
+  const Container& c;
+  auto begin() const -> typename Container::const_iterator { return c.begin(); }
+  auto end() const -> typename Container::const_iterator { return c.end(); }
+};
+}  // namespace detail
+
+template <typename T, typename Char>
+struct formatter<
+    T, Char,
+    enable_if_t<conjunction<detail::is_container_adaptor_like<T>,
+                            bool_constant<range_format_kind<T, Char>::value ==
+                                          range_format::disabled>>::value>>
+    : formatter<detail::all<typename T::container_type>, Char> {
+  using all = detail::all<typename T::container_type>;
+  template <typename FormatContext>
+  auto format(const T& t, FormatContext& ctx) const -> decltype(ctx.out()) {
+    struct getter : T {
+      static auto get(const T& t) -> all {
+        return {t.*(&getter::c)};  // Access c through the derived class.
+      }
+    };
+    return formatter<all>::format(getter::get(t), ctx);
+  }
+};
+
+FMT_BEGIN_EXPORT
+
 /**
   \rst
   Returns an object that formats `tuple` with elements separated by `sep`.
@@ -347,14 +700,15 @@ struct formatter<tuple_arg_join<Char, T...>, Char> {
   \endrst
  */
 template <typename... T>
-FMT_CONSTEXPR tuple_arg_join<char, T...> join(const std::tuple<T...>& tuple,
-                                              string_view sep) {
+FMT_CONSTEXPR auto join(const std::tuple<T...>& tuple, string_view sep)
+    -> tuple_join_view<char, T...> {
   return {tuple, sep};
 }
 
 template <typename... T>
-FMT_CONSTEXPR tuple_arg_join<wchar_t, T...> join(const std::tuple<T...>& tuple,
-                                                 wstring_view sep) {
+FMT_CONSTEXPR auto join(const std::tuple<T...>& tuple,
+                        basic_string_view<wchar_t> sep)
+    -> tuple_join_view<wchar_t, T...> {
   return {tuple, sep};
 }
 
@@ -370,17 +724,12 @@ FMT_CONSTEXPR tuple_arg_join<wchar_t, T...> join(const std::tuple<T...>& tuple,
   \endrst
  */
 template <typename T>
-arg_join<const T*, const T*, char> join(std::initializer_list<T> list,
-                                        string_view sep) {
-  return join(std::begin(list), std::end(list), sep);
-}
-
-template <typename T>
-arg_join<const T*, const T*, wchar_t> join(std::initializer_list<T> list,
-                                           wstring_view sep) {
+auto join(std::initializer_list<T> list, string_view sep)
+    -> join_view<const T*, const T*> {
   return join(std::begin(list), std::end(list), sep);
 }
 
+FMT_END_EXPORT
 FMT_END_NAMESPACE
 
 #endif  // FMT_RANGES_H_

include/fmt/std.h

@@ -0,0 +1,465 @@
+// Formatting library for C++ - formatters for standard library types
+//
+// Copyright (c) 2012 - present, Victor Zverovich
+// All rights reserved.
+//
+// For the license information refer to format.h.
+
+#ifndef FMT_STD_H_
+#define FMT_STD_H_
+
+#include <atomic>
+#include <bitset>
+#include <cstdlib>
+#include <exception>
+#include <memory>
+#include <thread>
+#include <type_traits>
+#include <typeinfo>
+#include <utility>
+#include <vector>
+
+#include "format.h"
+#include "ostream.h"
+
+#if FMT_HAS_INCLUDE(<version>)
+#  include <version>
+#endif
+// Checking FMT_CPLUSPLUS for warning suppression in MSVC.
+#if FMT_CPLUSPLUS >= 201703L
+#  if FMT_HAS_INCLUDE(<filesystem>)
+#    include <filesystem>
+#  endif
+#  if FMT_HAS_INCLUDE(<variant>)
+#    include <variant>
+#  endif
+#  if FMT_HAS_INCLUDE(<optional>)
+#    include <optional>
+#  endif
+#endif
+
+// GCC 4 does not support FMT_HAS_INCLUDE.
+#if FMT_HAS_INCLUDE(<cxxabi.h>) || defined(__GLIBCXX__)
+#  include <cxxabi.h>
+// Android NDK with gabi++ library on some architectures does not implement
+// abi::__cxa_demangle().
+#  ifndef __GABIXX_CXXABI_H__
+#    define FMT_HAS_ABI_CXA_DEMANGLE
+#  endif
+#endif
+
+// Check if typeid is available.
+#ifndef FMT_USE_TYPEID
+// __RTTI is for EDG compilers. In MSVC typeid is available without RTTI.
+#  if defined(__GXX_RTTI) || FMT_HAS_FEATURE(cxx_rtti) || FMT_MSC_VERSION || \
+      defined(__INTEL_RTTI__) || defined(__RTTI)
+#    define FMT_USE_TYPEID 1
+#  else
+#    define FMT_USE_TYPEID 0
+#  endif
+#endif
+
+#ifdef __cpp_lib_filesystem
+FMT_BEGIN_NAMESPACE
+
+namespace detail {
+
+template <typename Char> auto get_path_string(const std::filesystem::path& p) {
+  return p.string<Char>();
+}
+
+template <typename Char>
+void write_escaped_path(basic_memory_buffer<Char>& quoted,
+                        const std::filesystem::path& p) {
+  write_escaped_string<Char>(std::back_inserter(quoted), p.string<Char>());
+}
+
+#  ifdef _WIN32
+template <>
+inline auto get_path_string<char>(const std::filesystem::path& p) {
+  return to_utf8<wchar_t>(p.native(), to_utf8_error_policy::replace);
+}
+
+template <>
+inline void write_escaped_path<char>(memory_buffer& quoted,
+                                     const std::filesystem::path& p) {
+  auto buf = basic_memory_buffer<wchar_t>();
+  write_escaped_string<wchar_t>(std::back_inserter(buf), p.native());
+  bool valid = to_utf8<wchar_t>::convert(quoted, {buf.data(), buf.size()});
+  FMT_ASSERT(valid, "invalid utf16");
+}
+#  endif  // _WIN32
+
+template <>
+inline void write_escaped_path<std::filesystem::path::value_type>(
+    basic_memory_buffer<std::filesystem::path::value_type>& quoted,
+    const std::filesystem::path& p) {
+  write_escaped_string<std::filesystem::path::value_type>(
+      std::back_inserter(quoted), p.native());
+}
+
+}  // namespace detail
+
+FMT_EXPORT
+template <typename Char> struct formatter<std::filesystem::path, Char> {
+ private:
+  format_specs<Char> specs_;
+  detail::arg_ref<Char> width_ref_;
+  bool debug_ = false;
+
+ public:
+  FMT_CONSTEXPR void set_debug_format(bool set = true) { debug_ = set; }
+
+  template <typename ParseContext> FMT_CONSTEXPR auto parse(ParseContext& ctx) {
+    auto it = ctx.begin(), end = ctx.end();
+    if (it == end) return it;
+
+    it = detail::parse_align(it, end, specs_);
+    if (it == end) return it;
+
+    it = detail::parse_dynamic_spec(it, end, specs_.width, width_ref_, ctx);
+    if (it != end && *it == '?') {
+      debug_ = true;
+      ++it;
+    }
+    return it;
+  }
+
+  template <typename FormatContext>
+  auto format(const std::filesystem::path& p, FormatContext& ctx) const {
+    auto specs = specs_;
+    detail::handle_dynamic_spec<detail::width_checker>(specs.width, width_ref_,
+                                                       ctx);
+    if (!debug_) {
+      auto s = detail::get_path_string<Char>(p);
+      return detail::write(ctx.out(), basic_string_view<Char>(s), specs);
+    }
+    auto quoted = basic_memory_buffer<Char>();
+    detail::write_escaped_path(quoted, p);
+    return detail::write(ctx.out(),
+                         basic_string_view<Char>(quoted.data(), quoted.size()),
+                         specs);
+  }
+};
+FMT_END_NAMESPACE
+#endif
+
+FMT_BEGIN_NAMESPACE
+FMT_EXPORT
+template <typename Char>
+struct formatter<std::thread::id, Char> : basic_ostream_formatter<Char> {};
+FMT_END_NAMESPACE
+
+#ifdef __cpp_lib_optional
+FMT_BEGIN_NAMESPACE
+FMT_EXPORT
+template <typename T, typename Char>
+struct formatter<std::optional<T>, Char,
+                 std::enable_if_t<is_formattable<T, Char>::value>> {
+ private:
+  formatter<T, Char> underlying_;
+  static constexpr basic_string_view<Char> optional =
+      detail::string_literal<Char, 'o', 'p', 't', 'i', 'o', 'n', 'a', 'l',
+                             '('>{};
+  static constexpr basic_string_view<Char> none =
+      detail::string_literal<Char, 'n', 'o', 'n', 'e'>{};
+
+  template <class U>
+  FMT_CONSTEXPR static auto maybe_set_debug_format(U& u, bool set)
+      -> decltype(u.set_debug_format(set)) {
+    u.set_debug_format(set);
+  }
+
+  template <class U>
+  FMT_CONSTEXPR static void maybe_set_debug_format(U&, ...) {}
+
+ public:
+  template <typename ParseContext> FMT_CONSTEXPR auto parse(ParseContext& ctx) {
+    maybe_set_debug_format(underlying_, true);
+    return underlying_.parse(ctx);
+  }
+
+  template <typename FormatContext>
+  auto format(std::optional<T> const& opt, FormatContext& ctx) const
+      -> decltype(ctx.out()) {
+    if (!opt) return detail::write<Char>(ctx.out(), none);
+
+    auto out = ctx.out();
+    out = detail::write<Char>(out, optional);
+    ctx.advance_to(out);
+    out = underlying_.format(*opt, ctx);
+    return detail::write(out, ')');
+  }
+};
+FMT_END_NAMESPACE
+#endif  // __cpp_lib_optional
+
+#ifdef __cpp_lib_variant
+FMT_BEGIN_NAMESPACE
+namespace detail {
+
+template <typename T>
+using variant_index_sequence =
+    std::make_index_sequence<std::variant_size<T>::value>;
+
+template <typename> struct is_variant_like_ : std::false_type {};
+template <typename... Types>
+struct is_variant_like_<std::variant<Types...>> : std::true_type {};
+
+// formattable element check.
+template <typename T, typename C> class is_variant_formattable_ {
+  template <std::size_t... Is>
+  static std::conjunction<
+      is_formattable<std::variant_alternative_t<Is, T>, C>...>
+      check(std::index_sequence<Is...>);
+
+ public:
+  static constexpr const bool value =
+      decltype(check(variant_index_sequence<T>{}))::value;
+};
+
+template <typename Char, typename OutputIt, typename T>
+auto write_variant_alternative(OutputIt out, const T& v) -> OutputIt {
+  if constexpr (is_string<T>::value)
+    return write_escaped_string<Char>(out, detail::to_string_view(v));
+  else if constexpr (std::is_same_v<T, Char>)
+    return write_escaped_char(out, v);
+  else
+    return write<Char>(out, v);
+}
+
+}  // namespace detail
+
+template <typename T> struct is_variant_like {
+  static constexpr const bool value = detail::is_variant_like_<T>::value;
+};
+
+template <typename T, typename C> struct is_variant_formattable {
+  static constexpr const bool value =
+      detail::is_variant_formattable_<T, C>::value;
+};
+
+FMT_EXPORT
+template <typename Char> struct formatter<std::monostate, Char> {
+  template <typename ParseContext>
+  FMT_CONSTEXPR auto parse(ParseContext& ctx) -> decltype(ctx.begin()) {
+    return ctx.begin();
+  }
+
+  template <typename FormatContext>
+  auto format(const std::monostate&, FormatContext& ctx) const
+      -> decltype(ctx.out()) {
+    return detail::write<Char>(ctx.out(), "monostate");
+  }
+};
+
+FMT_EXPORT
+template <typename Variant, typename Char>
+struct formatter<
+    Variant, Char,
+    std::enable_if_t<std::conjunction_v<
+        is_variant_like<Variant>, is_variant_formattable<Variant, Char>>>> {
+  template <typename ParseContext>
+  FMT_CONSTEXPR auto parse(ParseContext& ctx) -> decltype(ctx.begin()) {
+    return ctx.begin();
+  }
+
+  template <typename FormatContext>
+  auto format(const Variant& value, FormatContext& ctx) const
+      -> decltype(ctx.out()) {
+    auto out = ctx.out();
+
+    out = detail::write<Char>(out, "variant(");
+    FMT_TRY {
+      std::visit(
+          [&](const auto& v) {
+            out = detail::write_variant_alternative<Char>(out, v);
+          },
+          value);
+    }
+    FMT_CATCH(const std::bad_variant_access&) {
+      detail::write<Char>(out, "valueless by exception");
+    }
+    *out++ = ')';
+    return out;
+  }
+};
+FMT_END_NAMESPACE
+#endif  // __cpp_lib_variant
+
+FMT_BEGIN_NAMESPACE
+FMT_EXPORT
+template <typename Char> struct formatter<std::error_code, Char> {
+  template <typename ParseContext>
+  FMT_CONSTEXPR auto parse(ParseContext& ctx) -> decltype(ctx.begin()) {
+    return ctx.begin();
+  }
+
+  template <typename FormatContext>
+  FMT_CONSTEXPR auto format(const std::error_code& ec, FormatContext& ctx) const
+      -> decltype(ctx.out()) {
+    auto out = ctx.out();
+    out = detail::write_bytes(out, ec.category().name(), format_specs<Char>());
+    out = detail::write<Char>(out, Char(':'));
+    out = detail::write<Char>(out, ec.value());
+    return out;
+  }
+};
+
+FMT_EXPORT
+template <typename T, typename Char>
+struct formatter<
+    T, Char,
+    typename std::enable_if<std::is_base_of<std::exception, T>::value>::type> {
+ private:
+  bool with_typename_ = false;
+
+ public:
+  FMT_CONSTEXPR auto parse(basic_format_parse_context<Char>& ctx)
+      -> decltype(ctx.begin()) {
+    auto it = ctx.begin();
+    auto end = ctx.end();
+    if (it == end || *it == '}') return it;
+    if (*it == 't') {
+      ++it;
+      with_typename_ = FMT_USE_TYPEID != 0;
+    }
+    return it;
+  }
+
+  template <typename OutputIt>
+  auto format(const std::exception& ex,
+              basic_format_context<OutputIt, Char>& ctx) const -> OutputIt {
+    format_specs<Char> spec;
+    auto out = ctx.out();
+    if (!with_typename_)
+      return detail::write_bytes(out, string_view(ex.what()), spec);
+
+#if FMT_USE_TYPEID
+    const std::type_info& ti = typeid(ex);
+#  ifdef FMT_HAS_ABI_CXA_DEMANGLE
+    int status = 0;
+    std::size_t size = 0;
+    std::unique_ptr<char, decltype(&std::free)> demangled_name_ptr(
+        abi::__cxa_demangle(ti.name(), nullptr, &size, &status), &std::free);
+
+    string_view demangled_name_view;
+    if (demangled_name_ptr) {
+      demangled_name_view = demangled_name_ptr.get();
+
+      // Normalization of stdlib inline namespace names.
+      // libc++ inline namespaces.
+      //  std::__1::*       -> std::*
+      //  std::__1::__fs::* -> std::*
+      // libstdc++ inline namespaces.
+      //  std::__cxx11::*             -> std::*
+      //  std::filesystem::__cxx11::* -> std::filesystem::*
+      if (demangled_name_view.starts_with("std::")) {
+        char* begin = demangled_name_ptr.get();
+        char* to = begin + 5;  // std::
+        for (char *from = to, *end = begin + demangled_name_view.size();
+             from < end;) {
+          // This is safe, because demangled_name is NUL-terminated.
+          if (from[0] == '_' && from[1] == '_') {
+            char* next = from + 1;
+            while (next < end && *next != ':') next++;
+            if (next[0] == ':' && next[1] == ':') {
+              from = next + 2;
+              continue;
+            }
+          }
+          *to++ = *from++;
+        }
+        demangled_name_view = {begin, detail::to_unsigned(to - begin)};
+      }
+    } else {
+      demangled_name_view = string_view(ti.name());
+    }
+    out = detail::write_bytes(out, demangled_name_view, spec);
+#  elif FMT_MSC_VERSION
+    string_view demangled_name_view(ti.name());
+    if (demangled_name_view.starts_with("class "))
+      demangled_name_view.remove_prefix(6);
+    else if (demangled_name_view.starts_with("struct "))
+      demangled_name_view.remove_prefix(7);
+    out = detail::write_bytes(out, demangled_name_view, spec);
+#  else
+    out = detail::write_bytes(out, string_view(ti.name()), spec);
+#  endif
+    *out++ = ':';
+    *out++ = ' ';
+    return detail::write_bytes(out, string_view(ex.what()), spec);
+#endif
+  }
+};
+
+namespace detail {
+
+template <typename T, typename Enable = void>
+struct has_flip : std::false_type {};
+
+template <typename T>
+struct has_flip<T, void_t<decltype(std::declval<T>().flip())>>
+    : std::true_type {};
+
+template <typename T> struct is_bit_reference_like {
+  static constexpr const bool value =
+      std::is_convertible<T, bool>::value &&
+      std::is_nothrow_assignable<T, bool>::value && has_flip<T>::value;
+};
+
+#ifdef _LIBCPP_VERSION
+
+// Workaround for libc++ incompatibility with C++ standard.
+// According to the Standard, `bitset::operator[] const` returns bool.
+template <typename C>
+struct is_bit_reference_like<std::__bit_const_reference<C>> {
+  static constexpr const bool value = true;
+};
+
+#endif
+
+}  // namespace detail
+
+// We can't use std::vector<bool, Allocator>::reference and
+// std::bitset<N>::reference because the compiler can't deduce Allocator and N
+// in partial specialization.
+FMT_EXPORT
+template <typename BitRef, typename Char>
+struct formatter<BitRef, Char,
+                 enable_if_t<detail::is_bit_reference_like<BitRef>::value>>
+    : formatter<bool, Char> {
+  template <typename FormatContext>
+  FMT_CONSTEXPR auto format(const BitRef& v, FormatContext& ctx) const
+      -> decltype(ctx.out()) {
+    return formatter<bool, Char>::format(v, ctx);
+  }
+};
+
+FMT_EXPORT
+template <typename T, typename Char>
+struct formatter<std::atomic<T>, Char,
+                 enable_if_t<is_formattable<T, Char>::value>>
+    : formatter<T, Char> {
+  template <typename FormatContext>
+  auto format(const std::atomic<T>& v, FormatContext& ctx) const
+      -> decltype(ctx.out()) {
+    return formatter<T, Char>::format(v.load(), ctx);
+  }
+};
+
+#ifdef __cpp_lib_atomic_flag_test
+FMT_EXPORT
+template <typename Char>
+struct formatter<std::atomic_flag, Char>
+    : formatter<bool, Char> {
+  template <typename FormatContext>
+  auto format(const std::atomic_flag& v, FormatContext& ctx) const
+      -> decltype(ctx.out()) {
+    return formatter<bool, Char>::format(v.test(), ctx);
+  }
+};
+#endif // __cpp_lib_atomic_flag_test
+
+FMT_END_NAMESPACE
+#endif  // FMT_STD_H_

include/fmt/xchar.h

@@ -0,0 +1,258 @@
+// Formatting library for C++ - optional wchar_t and exotic character support
+//
+// Copyright (c) 2012 - present, Victor Zverovich
+// All rights reserved.
+//
+// For the license information refer to format.h.
+
+#ifndef FMT_XCHAR_H_
+#define FMT_XCHAR_H_
+
+#include <cwchar>
+
+#include "format.h"
+
+#ifndef FMT_STATIC_THOUSANDS_SEPARATOR
+#  include <locale>
+#endif
+
+FMT_BEGIN_NAMESPACE
+namespace detail {
+
+template <typename T>
+using is_exotic_char = bool_constant<!std::is_same<T, char>::value>;
+
+inline auto write_loc(std::back_insert_iterator<detail::buffer<wchar_t>> out,
+                      loc_value value, const format_specs<wchar_t>& specs,
+                      locale_ref loc) -> bool {
+#ifndef FMT_STATIC_THOUSANDS_SEPARATOR
+  auto& numpunct =
+      std::use_facet<std::numpunct<wchar_t>>(loc.get<std::locale>());
+  auto separator = std::wstring();
+  auto grouping = numpunct.grouping();
+  if (!grouping.empty()) separator = std::wstring(1, numpunct.thousands_sep());
+  return value.visit(loc_writer<wchar_t>{out, specs, separator, grouping, {}});
+#endif
+  return false;
+}
+}  // namespace detail
+
+FMT_BEGIN_EXPORT
+
+using wstring_view = basic_string_view<wchar_t>;
+using wformat_parse_context = basic_format_parse_context<wchar_t>;
+using wformat_context = buffer_context<wchar_t>;
+using wformat_args = basic_format_args<wformat_context>;
+using wmemory_buffer = basic_memory_buffer<wchar_t>;
+
+#if FMT_GCC_VERSION && FMT_GCC_VERSION < 409
+// Workaround broken conversion on older gcc.
+template <typename... Args> using wformat_string = wstring_view;
+inline auto runtime(wstring_view s) -> wstring_view { return s; }
+#else
+template <typename... Args>
+using wformat_string = basic_format_string<wchar_t, type_identity_t<Args>...>;
+inline auto runtime(wstring_view s) -> runtime_format_string<wchar_t> {
+  return {{s}};
+}
+#endif
+
+template <> struct is_char<wchar_t> : std::true_type {};
+template <> struct is_char<detail::char8_type> : std::true_type {};
+template <> struct is_char<char16_t> : std::true_type {};
+template <> struct is_char<char32_t> : std::true_type {};
+
+template <typename... T>
+constexpr format_arg_store<wformat_context, T...> make_wformat_args(
+    const T&... args) {
+  return {args...};
+}
+
+inline namespace literals {
+#if FMT_USE_USER_DEFINED_LITERALS && !FMT_USE_NONTYPE_TEMPLATE_ARGS
+constexpr detail::udl_arg<wchar_t> operator"" _a(const wchar_t* s, size_t) {
+  return {s};
+}
+#endif
+}  // namespace literals
+
+template <typename It, typename Sentinel>
+auto join(It begin, Sentinel end, wstring_view sep)
+    -> join_view<It, Sentinel, wchar_t> {
+  return {begin, end, sep};
+}
+
+template <typename Range>
+auto join(Range&& range, wstring_view sep)
+    -> join_view<detail::iterator_t<Range>, detail::sentinel_t<Range>,
+                 wchar_t> {
+  return join(std::begin(range), std::end(range), sep);
+}
+
+template <typename T>
+auto join(std::initializer_list<T> list, wstring_view sep)
+    -> join_view<const T*, const T*, wchar_t> {
+  return join(std::begin(list), std::end(list), sep);
+}
+
+template <typename Char, FMT_ENABLE_IF(!std::is_same<Char, char>::value)>
+auto vformat(basic_string_view<Char> format_str,
+             basic_format_args<buffer_context<type_identity_t<Char>>> args)
+    -> std::basic_string<Char> {
+  auto buf = basic_memory_buffer<Char>();
+  detail::vformat_to(buf, format_str, args);
+  return to_string(buf);
+}
+
+template <typename... T>
+auto format(wformat_string<T...> fmt, T&&... args) -> std::wstring {
+  return vformat(fmt::wstring_view(fmt), fmt::make_wformat_args(args...));
+}
+
+// Pass char_t as a default template parameter instead of using
+// std::basic_string<char_t<S>> to reduce the symbol size.
+template <typename S, typename... T, typename Char = char_t<S>,
+          FMT_ENABLE_IF(!std::is_same<Char, char>::value &&
+                        !std::is_same<Char, wchar_t>::value)>
+auto format(const S& format_str, T&&... args) -> std::basic_string<Char> {
+  return vformat(detail::to_string_view(format_str),
+                 fmt::make_format_args<buffer_context<Char>>(args...));
+}
+
+template <typename Locale, typename S, typename Char = char_t<S>,
+          FMT_ENABLE_IF(detail::is_locale<Locale>::value&&
+                            detail::is_exotic_char<Char>::value)>
+inline auto vformat(
+    const Locale& loc, const S& format_str,
+    basic_format_args<buffer_context<type_identity_t<Char>>> args)
+    -> std::basic_string<Char> {
+  return detail::vformat(loc, detail::to_string_view(format_str), args);
+}
+
+template <typename Locale, typename S, typename... T, typename Char = char_t<S>,
+          FMT_ENABLE_IF(detail::is_locale<Locale>::value&&
+                            detail::is_exotic_char<Char>::value)>
+inline auto format(const Locale& loc, const S& format_str, T&&... args)
+    -> std::basic_string<Char> {
+  return detail::vformat(loc, detail::to_string_view(format_str),
+                         fmt::make_format_args<buffer_context<Char>>(args...));
+}
+
+template <typename OutputIt, typename S, typename Char = char_t<S>,
+          FMT_ENABLE_IF(detail::is_output_iterator<OutputIt, Char>::value&&
+                            detail::is_exotic_char<Char>::value)>
+auto vformat_to(OutputIt out, const S& format_str,
+                basic_format_args<buffer_context<type_identity_t<Char>>> args)
+    -> OutputIt {
+  auto&& buf = detail::get_buffer<Char>(out);
+  detail::vformat_to(buf, detail::to_string_view(format_str), args);
+  return detail::get_iterator(buf, out);
+}
+
+template <typename OutputIt, typename S, typename... T,
+          typename Char = char_t<S>,
+          FMT_ENABLE_IF(detail::is_output_iterator<OutputIt, Char>::value&&
+                            detail::is_exotic_char<Char>::value)>
+inline auto format_to(OutputIt out, const S& fmt, T&&... args) -> OutputIt {
+  return vformat_to(out, detail::to_string_view(fmt),
+                    fmt::make_format_args<buffer_context<Char>>(args...));
+}
+
+template <typename Locale, typename S, typename OutputIt, typename... Args,
+          typename Char = char_t<S>,
+          FMT_ENABLE_IF(detail::is_output_iterator<OutputIt, Char>::value&&
+                            detail::is_locale<Locale>::value&&
+                                detail::is_exotic_char<Char>::value)>
+inline auto vformat_to(
+    OutputIt out, const Locale& loc, const S& format_str,
+    basic_format_args<buffer_context<type_identity_t<Char>>> args) -> OutputIt {
+  auto&& buf = detail::get_buffer<Char>(out);
+  vformat_to(buf, detail::to_string_view(format_str), args,
+             detail::locale_ref(loc));
+  return detail::get_iterator(buf, out);
+}
+
+template <
+    typename OutputIt, typename Locale, typename S, typename... T,
+    typename Char = char_t<S>,
+    bool enable = detail::is_output_iterator<OutputIt, Char>::value&&
+        detail::is_locale<Locale>::value&& detail::is_exotic_char<Char>::value>
+inline auto format_to(OutputIt out, const Locale& loc, const S& format_str,
+                      T&&... args) ->
+    typename std::enable_if<enable, OutputIt>::type {
+  return vformat_to(out, loc, detail::to_string_view(format_str),
+                    fmt::make_format_args<buffer_context<Char>>(args...));
+}
+
+template <typename OutputIt, typename Char, typename... Args,
+          FMT_ENABLE_IF(detail::is_output_iterator<OutputIt, Char>::value&&
+                            detail::is_exotic_char<Char>::value)>
+inline auto vformat_to_n(
+    OutputIt out, size_t n, basic_string_view<Char> format_str,
+    basic_format_args<buffer_context<type_identity_t<Char>>> args)
+    -> format_to_n_result<OutputIt> {
+  using traits = detail::fixed_buffer_traits;
+  auto buf = detail::iterator_buffer<OutputIt, Char, traits>(out, n);
+  detail::vformat_to(buf, format_str, args);
+  return {buf.out(), buf.count()};
+}
+
+template <typename OutputIt, typename S, typename... T,
+          typename Char = char_t<S>,
+          FMT_ENABLE_IF(detail::is_output_iterator<OutputIt, Char>::value&&
+                            detail::is_exotic_char<Char>::value)>
+inline auto format_to_n(OutputIt out, size_t n, const S& fmt, T&&... args)
+    -> format_to_n_result<OutputIt> {
+  return vformat_to_n(out, n, detail::to_string_view(fmt),
+                      fmt::make_format_args<buffer_context<Char>>(args...));
+}
+
+template <typename S, typename... T, typename Char = char_t<S>,
+          FMT_ENABLE_IF(detail::is_exotic_char<Char>::value)>
+inline auto formatted_size(const S& fmt, T&&... args) -> size_t {
+  auto buf = detail::counting_buffer<Char>();
+  detail::vformat_to(buf, detail::to_string_view(fmt),
+                     fmt::make_format_args<buffer_context<Char>>(args...));
+  return buf.count();
+}
+
+inline void vprint(std::FILE* f, wstring_view fmt, wformat_args args) {
+  auto buf = wmemory_buffer();
+  detail::vformat_to(buf, fmt, args);
+  buf.push_back(L'\0');
+  if (std::fputws(buf.data(), f) == -1)
+    FMT_THROW(system_error(errno, FMT_STRING("cannot write to file")));
+}
+
+inline void vprint(wstring_view fmt, wformat_args args) {
+  vprint(stdout, fmt, args);
+}
+
+template <typename... T>
+void print(std::FILE* f, wformat_string<T...> fmt, T&&... args) {
+  return vprint(f, wstring_view(fmt), fmt::make_wformat_args(args...));
+}
+
+template <typename... T> void print(wformat_string<T...> fmt, T&&... args) {
+  return vprint(wstring_view(fmt), fmt::make_wformat_args(args...));
+}
+
+template <typename... T>
+void println(std::FILE* f, wformat_string<T...> fmt, T&&... args) {
+  return print(f, L"{}\n", fmt::format(fmt, std::forward<T>(args)...));
+}
+
+template <typename... T> void println(wformat_string<T...> fmt, T&&... args) {
+  return print(L"{}\n", fmt::format(fmt, std::forward<T>(args)...));
+}
+
+/**
+  Converts *value* to ``std::wstring`` using the default format for type *T*.
+ */
+template <typename T> inline auto to_wstring(const T& value) -> std::wstring {
+  return format(FMT_STRING(L"{}"), value);
+}
+FMT_END_EXPORT
+FMT_END_NAMESPACE
+
+#endif  // FMT_XCHAR_H_

src/fmt.cc

@@ -0,0 +1,110 @@
+module;
+
+// Put all implementation-provided headers into the global module fragment
+// to prevent attachment to this module.
+#include <algorithm>
+#include <cerrno>
+#include <chrono>
+#include <climits>
+#include <cmath>
+#include <cstddef>
+#include <cstdint>
+#include <cstdio>
+#include <cstdlib>
+#include <cstring>
+#include <ctime>
+#include <exception>
+#include <filesystem>
+#include <fstream>
+#include <functional>
+#include <iterator>
+#include <limits>
+#include <locale>
+#include <memory>
+#include <optional>
+#include <ostream>
+#include <stdexcept>
+#include <string>
+#include <string_view>
+#include <system_error>
+#include <thread>
+#include <type_traits>
+#include <typeinfo>
+#include <utility>
+#include <variant>
+#include <vector>
+#include <version>
+
+#if __has_include(<cxxabi.h>)
+#  include <cxxabi.h>
+#endif
+#if defined(_MSC_VER) || defined(__MINGW32__)
+#  include <intrin.h>
+#endif
+#if defined __APPLE__ || defined(__FreeBSD__)
+#  include <xlocale.h>
+#endif
+#if __has_include(<winapifamily.h>)
+#  include <winapifamily.h>
+#endif
+#if (__has_include(<fcntl.h>) || defined(__APPLE__) || \
+     defined(__linux__)) &&                            \
+    (!defined(WINAPI_FAMILY) || (WINAPI_FAMILY == WINAPI_FAMILY_DESKTOP_APP))
+#  include <fcntl.h>
+#  include <sys/stat.h>
+#  include <sys/types.h>
+#  ifndef _WIN32
+#    include <unistd.h>
+#  else
+#    include <io.h>
+#  endif
+#endif
+#ifdef _WIN32
+#  if defined(__GLIBCXX__)
+#    include <ext/stdio_filebuf.h>
+#    include <ext/stdio_sync_filebuf.h>
+#  elif defined(_LIBCPP_VERSION)
+#    include <__std_stream>
+#  endif
+#  define WIN32_LEAN_AND_MEAN
+#  include <windows.h>
+#endif
+
+export module fmt;
+
+#define FMT_EXPORT export
+#define FMT_BEGIN_EXPORT export {
+#define FMT_END_EXPORT }
+
+// If you define FMT_ATTACH_TO_GLOBAL_MODULE
+//  - all declarations are detached from module 'fmt'
+//  - the module behaves like a traditional static library, too
+//  - all library symbols are mangled traditionally
+//  - you can mix TUs with either importing or #including the {fmt} API
+#ifdef FMT_ATTACH_TO_GLOBAL_MODULE
+extern "C++" {
+#endif
+
+// All library-provided declarations and definitions must be in the module
+// purview to be exported.
+#include "fmt/args.h"
+#include "fmt/chrono.h"
+#include "fmt/color.h"
+#include "fmt/compile.h"
+#include "fmt/format.h"
+#include "fmt/os.h"
+#include "fmt/printf.h"
+#include "fmt/std.h"
+#include "fmt/xchar.h"
+
+#ifdef FMT_ATTACH_TO_GLOBAL_MODULE
+}
+#endif
+
+// gcc doesn't yet implement private module fragments
+#if !FMT_GCC_VERSION
+module : private;
+#endif
+
+#include "format.cc"
+#include "os.cc"

src/format.cc

@@ -10,60 +10,34 @@
 FMT_BEGIN_NAMESPACE
 namespace detail {
 
-template <typename T>
-int format_float(char* buf, std::size_t size, const char* format, int precision,
-                 T value) {
-#ifdef FMT_FUZZ
-  if (precision > 100000)
-    throw std::runtime_error(
-        "fuzz mode - avoid large allocation inside snprintf");
-#endif
-  // Suppress the warning about nonliteral format string.
-  int (*snprintf_ptr)(char*, size_t, const char*, ...) = FMT_SNPRINTF;
-  return precision < 0 ? snprintf_ptr(buf, size, format, value)
-                       : snprintf_ptr(buf, size, format, precision, value);
-}
-}  // namespace detail
-
-template struct FMT_INSTANTIATION_DEF_API detail::basic_data<void>;
-
-// Workaround a bug in MSVC2013 that prevents instantiation of format_float.
-int (*instantiate_format_float)(double, int, detail::float_specs,
-                                detail::buffer<char>&) = detail::format_float;
+template FMT_API auto dragonbox::to_decimal(float x) noexcept
+    -> dragonbox::decimal_fp<float>;
+template FMT_API auto dragonbox::to_decimal(double x) noexcept
+    -> dragonbox::decimal_fp<double>;
 
 #ifndef FMT_STATIC_THOUSANDS_SEPARATOR
-template FMT_API detail::locale_ref::locale_ref(const std::locale& loc);
-template FMT_API std::locale detail::locale_ref::get<std::locale>() const;
+template FMT_API locale_ref::locale_ref(const std::locale& loc);
+template FMT_API auto locale_ref::get<std::locale>() const -> std::locale;
 #endif
 
 // Explicit instantiations for char.
 
-template FMT_API std::string detail::grouping_impl<char>(locale_ref);
-template FMT_API char detail::thousands_sep_impl(locale_ref);
-template FMT_API char detail::decimal_point_impl(locale_ref);
+template FMT_API auto thousands_sep_impl(locale_ref)
+    -> thousands_sep_result<char>;
+template FMT_API auto decimal_point_impl(locale_ref) -> char;
 
-template FMT_API void detail::buffer<char>::append(const char*, const char*);
+template FMT_API void buffer<char>::append(const char*, const char*);
 
-template FMT_API FMT_BUFFER_CONTEXT(char)::iterator detail::vformat_to(
-    detail::buffer<char>&, string_view,
-    basic_format_args<FMT_BUFFER_CONTEXT(char)>);
-
-template FMT_API int detail::snprintf_float(double, int, detail::float_specs,
-                                            detail::buffer<char>&);
-template FMT_API int detail::snprintf_float(long double, int,
-                                            detail::float_specs,
-                                            detail::buffer<char>&);
-template FMT_API int detail::format_float(double, int, detail::float_specs,
-                                          detail::buffer<char>&);
-template FMT_API int detail::format_float(long double, int, detail::float_specs,
-                                          detail::buffer<char>&);
+template FMT_API void vformat_to(buffer<char>&, string_view,
+                                 typename vformat_args<>::type, locale_ref);
 
 // Explicit instantiations for wchar_t.
 
-template FMT_API std::string detail::grouping_impl<wchar_t>(locale_ref);
-template FMT_API wchar_t detail::thousands_sep_impl(locale_ref);
-template FMT_API wchar_t detail::decimal_point_impl(locale_ref);
+template FMT_API auto thousands_sep_impl(locale_ref)
+    -> thousands_sep_result<wchar_t>;
+template FMT_API auto decimal_point_impl(locale_ref) -> wchar_t;
 
-template FMT_API void detail::buffer<wchar_t>::append(const wchar_t*,
-                                                      const wchar_t*);
+template FMT_API void buffer<wchar_t>::append(const wchar_t*, const wchar_t*);
+
+}  // namespace detail
 FMT_END_NAMESPACE

src/os.cc

@@ -18,6 +18,10 @@
 #  include <sys/stat.h>
 #  include <sys/types.h>
 
+#  ifdef _WRS_KERNEL   // VxWorks7 kernel
+#    include <ioLib.h> // getpagesize
+#  endif
+
 #  ifndef _WIN32
 #    include <unistd.h>
 #  else
@@ -25,21 +29,24 @@
 #      define WIN32_LEAN_AND_MEAN
 #    endif
 #    include <io.h>
-#    include <windows.h>
-
-#    define O_CREAT _O_CREAT
-#    define O_TRUNC _O_TRUNC
 
 #    ifndef S_IRUSR
 #      define S_IRUSR _S_IREAD
 #    endif
-
 #    ifndef S_IWUSR
 #      define S_IWUSR _S_IWRITE
 #    endif
-
-#    ifdef __MINGW32__
-#      define _SH_DENYNO 0x40
+#    ifndef S_IRGRP
+#      define S_IRGRP 0
+#    endif
+#    ifndef S_IWGRP
+#      define S_IWGRP 0
+#    endif
+#    ifndef S_IROTH
+#      define S_IROTH 0
+#    endif
+#    ifndef S_IWOTH
+#      define S_IWOTH 0
 #    endif
 #  endif  // _WIN32
 #endif    // FMT_USE_FCNTL
@@ -48,23 +55,19 @@
 #  include <windows.h>
 #endif
 
-#ifdef fileno
-#  undef fileno
-#endif
-
 namespace {
 #ifdef _WIN32
 // Return type of read and write functions.
-using RWResult = int;
+using rwresult = int;
 
 // On Windows the count argument to read and write is unsigned, so convert
 // it from size_t preventing integer overflow.
 inline unsigned convert_rwcount(std::size_t count) {
   return count <= UINT_MAX ? static_cast<unsigned>(count) : UINT_MAX;
 }
-#else
+#elif FMT_USE_FCNTL
 // Return type of read and write functions.
-using RWResult = ssize_t;
+using rwresult = ssize_t;
 
 inline std::size_t convert_rwcount(std::size_t count) { return count; }
 #endif
@@ -73,78 +76,91 @@ inline std::size_t convert_rwcount(std::size_t count) { return count; }
 FMT_BEGIN_NAMESPACE
 
 #ifdef _WIN32
-detail::utf16_to_utf8::utf16_to_utf8(wstring_view s) {
-  if (int error_code = convert(s)) {
-    FMT_THROW(windows_error(error_code,
-                            "cannot convert string from UTF-16 to UTF-8"));
-  }
-}
+namespace detail {
 
-int detail::utf16_to_utf8::convert(wstring_view s) {
-  if (s.size() > INT_MAX) return ERROR_INVALID_PARAMETER;
-  int s_size = static_cast<int>(s.size());
-  if (s_size == 0) {
-    // WideCharToMultiByte does not support zero length, handle separately.
-    buffer_.resize(1);
-    buffer_[0] = 0;
-    return 0;
+class system_message {
+  system_message(const system_message&) = delete;
+  void operator=(const system_message&) = delete;
+
+  unsigned long result_;
+  wchar_t* message_;
+
+  static bool is_whitespace(wchar_t c) noexcept {
+    return c == L' ' || c == L'\n' || c == L'\r' || c == L'\t' || c == L'\0';
   }
 
-  int length = WideCharToMultiByte(CP_UTF8, 0, s.data(), s_size, nullptr, 0,
-                                   nullptr, nullptr);
-  if (length == 0) return GetLastError();
-  buffer_.resize(length + 1);
-  length = WideCharToMultiByte(CP_UTF8, 0, s.data(), s_size, &buffer_[0],
-                               length, nullptr, nullptr);
-  if (length == 0) return GetLastError();
-  buffer_[length] = 0;
-  return 0;
+ public:
+  explicit system_message(unsigned long error_code)
+      : result_(0), message_(nullptr) {
+    result_ = FormatMessageW(
+        FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM |
+            FORMAT_MESSAGE_IGNORE_INSERTS,
+        nullptr, error_code, MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
+        reinterpret_cast<wchar_t*>(&message_), 0, nullptr);
+    if (result_ != 0) {
+      while (result_ != 0 && is_whitespace(message_[result_ - 1])) {
+        --result_;
+      }
+    }
+  }
+  ~system_message() { LocalFree(message_); }
+  explicit operator bool() const noexcept { return result_ != 0; }
+  operator basic_string_view<wchar_t>() const noexcept {
+    return basic_string_view<wchar_t>(message_, result_);
+  }
+};
+
+class utf8_system_category final : public std::error_category {
+ public:
+  const char* name() const noexcept override { return "system"; }
+  std::string message(int error_code) const override {
+    auto&& msg = system_message(error_code);
+    if (msg) {
+      auto utf8_message = to_utf8<wchar_t>();
+      if (utf8_message.convert(msg)) {
+        return utf8_message.str();
+      }
+    }
+    return "unknown error";
+  }
+};
+
+}  // namespace detail
+
+FMT_API const std::error_category& system_category() noexcept {
+  static const detail::utf8_system_category category;
+  return category;
 }
 
-void windows_error::init(int err_code, string_view format_str,
-                         format_args args) {
-  error_code_ = err_code;
-  memory_buffer buffer;
-  detail::format_windows_error(buffer, err_code, vformat(format_str, args));
-  std::runtime_error& base = *this;
-  base = std::runtime_error(to_string(buffer));
+std::system_error vwindows_error(int err_code, string_view format_str,
+                                 format_args args) {
+  auto ec = std::error_code(err_code, system_category());
+  return std::system_error(ec, vformat(format_str, args));
 }
 
 void detail::format_windows_error(detail::buffer<char>& out, int error_code,
-                                  string_view message) FMT_NOEXCEPT {
+                                  const char* message) noexcept {
   FMT_TRY {
-    wmemory_buffer buf;
-    buf.resize(inline_buffer_size);
-    for (;;) {
-      wchar_t* system_message = &buf[0];
-      int result = FormatMessageW(
-          FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS, nullptr,
-          error_code, MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), system_message,
-          static_cast<uint32_t>(buf.size()), nullptr);
-      if (result != 0) {
-        utf16_to_utf8 utf8_message;
-        if (utf8_message.convert(system_message) == ERROR_SUCCESS) {
-          format_to(std::back_inserter(out), "{}: {}", message, utf8_message);
-          return;
-        }
-        break;
+    auto&& msg = system_message(error_code);
+    if (msg) {
+      auto utf8_message = to_utf8<wchar_t>();
+      if (utf8_message.convert(msg)) {
+        fmt::format_to(appender(out), FMT_STRING("{}: {}"), message,
+                       string_view(utf8_message));
+        return;
       }
-      if (GetLastError() != ERROR_INSUFFICIENT_BUFFER)
-        break;  // Can't get error message, report error code instead.
-      buf.resize(buf.size() * 2);
     }
   }
   FMT_CATCH(...) {}
   format_error_code(out, error_code, message);
 }
 
-void report_windows_error(int error_code,
-                          fmt::string_view message) FMT_NOEXCEPT {
+void report_windows_error(int error_code, const char* message) noexcept {
   report_error(detail::format_windows_error, error_code, message);
 }
 #endif  // _WIN32
 
-buffered_file::~buffered_file() FMT_NOEXCEPT {
+buffered_file::~buffered_file() noexcept {
   if (file_ && FMT_SYSTEM(fclose(file_)) != 0)
     report_system_error(errno, "cannot close file");
 }
@@ -153,39 +169,50 @@ buffered_file::buffered_file(cstring_view filename, cstring_view mode) {
   FMT_RETRY_VAL(file_, FMT_SYSTEM(fopen(filename.c_str(), mode.c_str())),
                 nullptr);
   if (!file_)
-    FMT_THROW(system_error(errno, "cannot open file {}", filename.c_str()));
+    FMT_THROW(system_error(errno, FMT_STRING("cannot open file {}"),
+                           filename.c_str()));
 }
 
 void buffered_file::close() {
   if (!file_) return;
   int result = FMT_SYSTEM(fclose(file_));
   file_ = nullptr;
-  if (result != 0) FMT_THROW(system_error(errno, "cannot close file"));
+  if (result != 0)
+    FMT_THROW(system_error(errno, FMT_STRING("cannot close file")));
 }
 
-// A macro used to prevent expansion of fileno on broken versions of MinGW.
-#define FMT_ARGS
-
-int buffered_file::fileno() const {
-  int fd = FMT_POSIX_CALL(fileno FMT_ARGS(file_));
-  if (fd == -1) FMT_THROW(system_error(errno, "cannot get file descriptor"));
+int buffered_file::descriptor() const {
+#ifdef fileno  // fileno is a macro on OpenBSD so we cannot use FMT_POSIX_CALL.
+  int fd = fileno(file_);
+#else
+  int fd = FMT_POSIX_CALL(fileno(file_));
+#endif
+  if (fd == -1)
+    FMT_THROW(system_error(errno, FMT_STRING("cannot get file descriptor")));
   return fd;
 }
 
 #if FMT_USE_FCNTL
+#  ifdef _WIN32
+using mode_t = int;
+#  endif
+constexpr mode_t default_open_mode =
+    S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH;
+
 file::file(cstring_view path, int oflag) {
-  int mode = S_IRUSR | S_IWUSR;
 #  if defined(_WIN32) && !defined(__MINGW32__)
   fd_ = -1;
-  FMT_POSIX_CALL(sopen_s(&fd_, path.c_str(), oflag, _SH_DENYNO, mode));
+  auto converted = detail::utf8_to_utf16(string_view(path.c_str()));
+  *this = file::open_windows_file(converted.c_str(), oflag);
 #  else
-  FMT_RETRY(fd_, FMT_POSIX_CALL(open(path.c_str(), oflag, mode)));
-#  endif
+  FMT_RETRY(fd_, FMT_POSIX_CALL(open(path.c_str(), oflag, default_open_mode)));
   if (fd_ == -1)
-    FMT_THROW(system_error(errno, "cannot open file {}", path.c_str()));
+    FMT_THROW(
+        system_error(errno, FMT_STRING("cannot open file {}"), path.c_str()));
+#  endif
 }
 
-file::~file() FMT_NOEXCEPT {
+file::~file() noexcept {
   // Don't retry close in case of EINTR!
   // See http://linux.derkeiler.com/Mailing-Lists/Kernel/2005-09/3000.html
   if (fd_ != -1 && FMT_POSIX_CALL(close(fd_)) != 0)
@@ -198,7 +225,8 @@ void file::close() {
   // See http://linux.derkeiler.com/Mailing-Lists/Kernel/2005-09/3000.html
   int result = FMT_POSIX_CALL(close(fd_));
   fd_ = -1;
-  if (result != 0) FMT_THROW(system_error(errno, "cannot close file"));
+  if (result != 0)
+    FMT_THROW(system_error(errno, FMT_STRING("cannot close file")));
 }
 
 long long file::size() const {
@@ -220,7 +248,7 @@ long long file::size() const {
   using Stat = struct stat;
   Stat file_stat = Stat();
   if (FMT_POSIX_CALL(fstat(fd_, &file_stat)) == -1)
-    FMT_THROW(system_error(errno, "cannot get file attributes"));
+    FMT_THROW(system_error(errno, FMT_STRING("cannot get file attributes")));
   static_assert(sizeof(long long) >= sizeof(file_stat.st_size),
                 "return type of file::size is not large enough");
   return file_stat.st_size;
@@ -228,16 +256,18 @@ long long file::size() const {
 }
 
 std::size_t file::read(void* buffer, std::size_t count) {
-  RWResult result = 0;
+  rwresult result = 0;
   FMT_RETRY(result, FMT_POSIX_CALL(read(fd_, buffer, convert_rwcount(count))));
-  if (result < 0) FMT_THROW(system_error(errno, "cannot read from file"));
+  if (result < 0)
+    FMT_THROW(system_error(errno, FMT_STRING("cannot read from file")));
   return detail::to_unsigned(result);
 }
 
 std::size_t file::write(const void* buffer, std::size_t count) {
-  RWResult result = 0;
+  rwresult result = 0;
   FMT_RETRY(result, FMT_POSIX_CALL(write(fd_, buffer, convert_rwcount(count))));
-  if (result < 0) FMT_THROW(system_error(errno, "cannot write to file"));
+  if (result < 0)
+    FMT_THROW(system_error(errno, FMT_STRING("cannot write to file")));
   return detail::to_unsigned(result);
 }
 
@@ -246,7 +276,8 @@ file file::dup(int fd) {
   // http://pubs.opengroup.org/onlinepubs/009695399/functions/dup.html
   int new_fd = FMT_POSIX_CALL(dup(fd));
   if (new_fd == -1)
-    FMT_THROW(system_error(errno, "cannot duplicate file descriptor {}", fd));
+    FMT_THROW(system_error(
+        errno, FMT_STRING("cannot duplicate file descriptor {}"), fd));
   return file(new_fd);
 }
 
@@ -254,15 +285,16 @@ void file::dup2(int fd) {
   int result = 0;
   FMT_RETRY(result, FMT_POSIX_CALL(dup2(fd_, fd)));
   if (result == -1) {
-    FMT_THROW(system_error(errno, "cannot duplicate file descriptor {} to {}",
-                           fd_, fd));
+    FMT_THROW(system_error(
+        errno, FMT_STRING("cannot duplicate file descriptor {} to {}"), fd_,
+        fd));
   }
 }
 
-void file::dup2(int fd, error_code& ec) FMT_NOEXCEPT {
+void file::dup2(int fd, std::error_code& ec) noexcept {
   int result = 0;
   FMT_RETRY(result, FMT_POSIX_CALL(dup2(fd_, fd)));
-  if (result == -1) ec = error_code(errno);
+  if (result == -1) ec = std::error_code(errno, std::generic_category());
 }
 
 void file::pipe(file& read_end, file& write_end) {
@@ -280,7 +312,8 @@ void file::pipe(file& read_end, file& write_end) {
   // http://pubs.opengroup.org/onlinepubs/009696799/functions/pipe.html
   int result = FMT_POSIX_CALL(pipe(fds));
 #  endif
-  if (result != 0) FMT_THROW(system_error(errno, "cannot create pipe"));
+  if (result != 0)
+    FMT_THROW(system_error(errno, FMT_STRING("cannot create pipe")));
   // The following assignments don't throw because read_fd and write_fd
   // are closed.
   read_end = file(fds[0]);
@@ -288,30 +321,78 @@ void file::pipe(file& read_end, file& write_end) {
 }
 
 buffered_file file::fdopen(const char* mode) {
-  // Don't retry as fdopen doesn't return EINTR.
-  #if defined(__MINGW32__) && defined(_POSIX_)
+// Don't retry as fdopen doesn't return EINTR.
+#  if defined(__MINGW32__) && defined(_POSIX_)
   FILE* f = ::fdopen(fd_, mode);
-  #else
+#  else
   FILE* f = FMT_POSIX_CALL(fdopen(fd_, mode));
-  #endif
-  if (!f)
-    FMT_THROW(
-        system_error(errno, "cannot associate stream with file descriptor"));
+#  endif
+  if (!f) {
+    FMT_THROW(system_error(
+        errno, FMT_STRING("cannot associate stream with file descriptor")));
+  }
   buffered_file bf(f);
   fd_ = -1;
   return bf;
 }
 
+#  if defined(_WIN32) && !defined(__MINGW32__)
+file file::open_windows_file(wcstring_view path, int oflag) {
+  int fd = -1;
+  auto err = _wsopen_s(&fd, path.c_str(), oflag, _SH_DENYNO, default_open_mode);
+  if (fd == -1) {
+    FMT_THROW(system_error(err, FMT_STRING("cannot open file {}"),
+                           detail::to_utf8<wchar_t>(path.c_str()).c_str()));
+  }
+  return file(fd);
+}
+#  endif
+
+#  if !defined(__MSDOS__)
 long getpagesize() {
-#  ifdef _WIN32
+#    ifdef _WIN32
   SYSTEM_INFO si;
   GetSystemInfo(&si);
   return si.dwPageSize;
-#  else
+#    else
+#      ifdef _WRS_KERNEL
+  long size = FMT_POSIX_CALL(getpagesize());
+#      else
   long size = FMT_POSIX_CALL(sysconf(_SC_PAGESIZE));
-  if (size < 0) FMT_THROW(system_error(errno, "cannot get memory page size"));
+#      endif
+
+  if (size < 0)
+    FMT_THROW(system_error(errno, FMT_STRING("cannot get memory page size")));
   return size;
-#  endif
+#    endif
 }
+#  endif
+
+namespace detail {
+
+void file_buffer::grow(size_t) {
+  if (this->size() == this->capacity()) flush();
+}
+
+file_buffer::file_buffer(cstring_view path,
+                         const detail::ostream_params& params)
+    : file_(path, params.oflag) {
+  set(new char[params.buffer_size], params.buffer_size);
+}
+
+file_buffer::file_buffer(file_buffer&& other)
+    : detail::buffer<char>(other.data(), other.size(), other.capacity()),
+      file_(std::move(other.file_)) {
+  other.clear();
+  other.set(nullptr, 0);
+}
+
+file_buffer::~file_buffer() {
+  flush();
+  delete[] data();
+}
+}  // namespace detail
+
+ostream::~ostream() = default;
 #endif  // FMT_USE_FCNTL
 FMT_END_NAMESPACE

support/README

@@ -2,5 +2,3 @@ This directory contains build support files such as
 
 * CMake modules
 * Build scripts
-* qmake (static build with dynamic libc only)
-

support/Vagrantfile

@@ -13,8 +13,8 @@ Vagrant.configure("2") do |config|
   config.vm.provision "shell", inline: <<-SHELL
     apt-get update
     apt-get install -y g++ make wget git
-    wget -q https://github.com/Kitware/CMake/releases/download/v3.14.4/cmake-3.14.4-Linux-x86_64.tar.gz
-    tar xzf cmake-3.14.4-Linux-x86_64.tar.gz
-    ln -s `pwd`/cmake-3.14.4-Linux-x86_64/bin/cmake /usr/local/bin
+    wget -q https://github.com/Kitware/CMake/releases/download/v3.26.0/cmake-3.26.0-Linux-x86_64.tar.gz
+    tar xzf cmake-3.26.0-Linux-x86_64.tar.gz
+    ln -s `pwd`/cmake-3.26.0-Linux-x86_64/bin/cmake /usr/local/bin
   SHELL
 end

support/appveyor-build.py

@@ -1,43 +0,0 @@
-#!/usr/bin/env python
-# Build the project on AppVeyor.
-
-import os
-from subprocess import check_call
-
-build = os.environ['BUILD']
-config = os.environ['CONFIGURATION']
-platform = os.environ['PLATFORM']
-path = os.environ['PATH']
-image = os.environ['APPVEYOR_BUILD_WORKER_IMAGE']
-jobid = os.environ['APPVEYOR_JOB_ID']
-cmake_command = ['cmake', '-DFMT_PEDANTIC=ON', '-DCMAKE_BUILD_TYPE=' + config, '..']
-if build == 'mingw':
-    cmake_command.append('-GMinGW Makefiles')
-    build_command = ['mingw32-make', '-j4']
-    test_command = ['mingw32-make', 'test']
-    # Remove the path to Git bin directory from $PATH because it breaks
-    # MinGW config.
-    path = path.replace(r'C:\Program Files (x86)\Git\bin', '')
-    os.environ['PATH'] = r'C:\MinGW\bin;' + path
-else:
-    # Add MSBuild 14.0 to PATH as described in
-    # http://help.appveyor.com/discussions/problems/2229-v140-not-found-on-vs2105rc.
-    os.environ['PATH'] = r'C:\Program Files (x86)\MSBuild\15.0\Bin;' + path
-    if image == 'Visual Studio 2019':
-        generator = 'Visual Studio 16 2019'
-        if platform == 'x64':
-            cmake_command.extend(['-A', 'x64'])
-    else:
-        if image == 'Visual Studio 2015':
-            generator = 'Visual Studio 14 2015'
-        elif image == 'Visual Studio 2017':
-            generator = 'Visual Studio 15 2017'
-        if platform == 'x64':
-            generator += ' Win64'
-    cmake_command.append('-G' + generator)
-    build_command = ['cmake', '--build', '.', '--config', config, '--', '/m:4']
-    test_command = ['ctest', '-C', config]
-
-check_call(cmake_command)
-check_call(build_command)
-check_call(test_command)

support/appveyor.yml

@@ -1,41 +0,0 @@
-configuration:
-  - Debug
-  - Release
-
-clone_depth: 1
-
-image:
-  - Visual Studio 2015
-  - Visual Studio 2019
-  - Visual Studio 2017
-
-platform:
-  - Win32
-  - x64
-
-environment:
-  CTEST_OUTPUT_ON_FAILURE: 1
-  MSVC_DEFAULT_OPTIONS: ON
-  BUILD: msvc
-
-matrix:
-  exclude:
-    - image: Visual Studio 2015
-      platform: Win32
-    - image: Visual Studio 2019
-      platform: Win32
-
-before_build:
- - mkdir build
- - cd build
-
-build_script:
-  - python ../support/appveyor-build.py
-
-on_failure:
-  - appveyor PushArtifact Testing/Temporary/LastTest.log
-  - appveyor AddTest test
-
-# Uncomment this to debug AppVeyor failures.
-#on_finish:
-#  - ps: $blockRdp = $true; iex ((new-object net.webclient).DownloadString('https://raw.githubusercontent.com/appveyor/ci/master/scripts/enable-rdp.ps1'))

support/bazel/.bazelversion

@@ -0,0 +1 @@
+6.1.2

support/bazel/BUILD.bazel

@@ -0,0 +1,28 @@
+cc_library(
+    name = "fmt",
+    srcs = [
+        #"src/fmt.cc", # No C++ module support
+        "src/format.cc",
+        "src/os.cc",
+    ],
+    hdrs = [
+        "include/fmt/args.h",
+        "include/fmt/chrono.h",
+        "include/fmt/color.h",
+        "include/fmt/compile.h",
+        "include/fmt/core.h",
+        "include/fmt/format.h",
+        "include/fmt/format-inl.h",
+        "include/fmt/os.h",
+        "include/fmt/ostream.h",
+        "include/fmt/printf.h",
+        "include/fmt/ranges.h",
+        "include/fmt/std.h",
+        "include/fmt/xchar.h",
+    ],
+    includes = [
+        "include",
+    ],
+    strip_include_prefix = "include",
+    visibility = ["//visibility:public"],
+)

support/bazel/README.md

@@ -0,0 +1,74 @@
+# Bazel support
+
+To get [Bazel](https://bazel.build/) working with {fmt} you can copy the files `BUILD.bazel`, `WORKSPACE.bazel`, and `.bazelversion` from this folder (`support/bazel`) to the root folder of this project. This way {fmt} gets bazelized and can be used with Bazel (e.g. doing a `bazel build //...` on {fmt}). 
+
+## Using {fmt} as a dependency
+
+The following minimal example shows how to use {fmt} as a dependency within a Bazel project.
+
+The following file structure is assumed:
+
+```
+example
+├── BUILD.bazel
+├── main.cpp
+└── WORKSPACE.bazel
+```
+
+*main.cpp*:
+
+```c++
+#include "fmt/core.h"
+
+int main() {
+  fmt::print("The answer is {}\n", 42);
+}
+```
+
+The expected output of this example is `The answer is 42`.
+
+*WORKSPACE.bazel*:
+
+```python
+load("@bazel_tools//tools/build_defs/repo:git.bzl", "git_repository")
+
+git_repository(
+    name = "fmt",
+    branch = "master",
+    remote = "https://github.com/fmtlib/fmt",
+    patch_cmds = [
+        "mv support/bazel/.bazelversion .bazelversion",
+        "mv support/bazel/BUILD.bazel BUILD.bazel",
+        "mv support/bazel/WORKSPACE.bazel WORKSPACE.bazel",
+    ],
+    # Windows-related patch commands are only needed in the case MSYS2 is not installed.
+    # More details about the installation process of MSYS2 on Windows systems can be found here:
+    # https://docs.bazel.build/versions/main/install-windows.html#installing-compilers-and-language-runtimes
+    # Even if MSYS2 is installed the Windows related patch commands can still be used.
+    patch_cmds_win = [
+        "Move-Item -Path support/bazel/.bazelversion -Destination .bazelversion",
+        "Move-Item -Path support/bazel/BUILD.bazel -Destination BUILD.bazel",
+        "Move-Item -Path support/bazel/WORKSPACE.bazel -Destination WORKSPACE.bazel",
+    ],
+)
+```
+
+In the *WORKSPACE* file, the {fmt} GitHub repository is fetched. Using the attribute `patch_cmds` the  files `BUILD.bazel`, `WORKSPACE.bazel`, and `.bazelversion` are moved to the root of the {fmt} repository. This way the {fmt} repository is recognized as a bazelized workspace. 
+
+*BUILD.bazel*:
+
+```python
+cc_binary(
+    name = "Demo",
+    srcs = ["main.cpp"],
+    deps = ["@fmt"],
+)
+```
+
+The *BUILD* file defines a binary named `Demo` that has a dependency to {fmt}.
+
+To execute the binary you can run `bazel run //:Demo`.
+
+# Using Bzlmod
+
+The [Bazel Central Registry](https://github.com/bazelbuild/bazel-central-registry/tree/main/modules/fmt) also provides support for {fmt}.

support/bazel/WORKSPACE.bazel

@@ -0,0 +1 @@
+workspace(name = "fmt")

support/build-docs.py

@@ -0,0 +1,58 @@
+#!/usr/bin/env python
+# Build the documentation in CI.
+
+from __future__ import print_function
+import errno, os, shutil, subprocess, sys, urllib
+from subprocess import call, check_call, Popen, PIPE, STDOUT
+
+def rmtree_if_exists(dir):
+    try:
+        shutil.rmtree(dir)
+    except OSError as e:
+        if e.errno == errno.ENOENT:
+            pass
+
+# Build the docs.
+fmt_dir = os.path.dirname(os.path.dirname(os.path.realpath(__file__)))
+sys.path.insert(0, os.path.join(fmt_dir, 'doc'))
+import build
+build.create_build_env()
+html_dir = build.build_docs()
+
+repo = 'fmtlib.github.io'
+branch = os.environ['GITHUB_REF']
+is_ci = 'CI' in os.environ
+if is_ci and branch != 'refs/heads/master':
+    print('Branch: ' + branch)
+    exit(0) # Ignore non-master branches
+if is_ci and 'KEY' not in os.environ:
+    # Don't update the repo if building in CI from an account that doesn't have
+    # push access.
+    print('Skipping update of ' + repo)
+    exit(0)
+
+# Clone the fmtlib.github.io repo.
+rmtree_if_exists(repo)
+git_url = 'https://github.com/' if is_ci else 'git@github.com:'
+check_call(['git', 'clone', git_url + 'fmtlib/{}.git'.format(repo)])
+
+# Copy docs to the repo.
+target_dir = os.path.join(repo, 'dev')
+rmtree_if_exists(target_dir)
+shutil.copytree(html_dir, target_dir, ignore=shutil.ignore_patterns('.*'))
+if is_ci:
+    check_call(['git', 'config', '--global', 'user.name', 'fmtbot'])
+    check_call(['git', 'config', '--global', 'user.email', 'viz@fmt.dev'])
+
+# Push docs to GitHub pages.
+check_call(['git', 'add', '--all'], cwd=repo)
+if call(['git', 'diff-index', '--quiet', 'HEAD'], cwd=repo):
+    check_call(['git', 'commit', '-m', 'Update documentation'], cwd=repo)
+    cmd = 'git push'
+    if is_ci:
+        cmd += ' https://$KEY@github.com/fmtlib/fmtlib.github.io.git master'
+    p = Popen(cmd, shell=True, stdout=PIPE, stderr=STDOUT, cwd=repo)
+    # Print the output without the key.
+    print(p.communicate()[0].decode('utf-8').replace(os.environ['KEY'], '$KEY'))
+    if p.returncode != 0:
+        raise subprocess.CalledProcessError(p.returncode, cmd)

support/build.gradle

@@ -1,3 +1,4 @@
+import java.nio.file.Paths
 
 // General gradle arguments for root project
 buildscript {    
@@ -7,24 +8,25 @@ buildscript {
     }
     dependencies {
         //
-        // https://developer.android.com/studio/releases/gradle-plugin
+        // https://developer.android.com/studio/releases/gradle-plugin#updating-gradle
         //
-        // Notice that 3.3.0 here is the version of [Android Gradle Plugin]
-        // Accroding to URL above you will need Gradle 5.0 or higher
+        // Notice that 4.0.0 here is the version of [Android Gradle Plugin]
+        // According to URL above you will need Gradle 6.1 or higher
         //
-        // If you are using Android Studio, and it is using Gradle's lower 
-        // version, Use the plugin version 3.1.3 ~ 3.2.0 for Gradle 4.4 ~ 4.10
-        classpath 'com.android.tools.build:gradle:3.3.0'
+        classpath "com.android.tools.build:gradle:4.1.1"
     }
 }
 repositories {
     google()
     jcenter()
 }
-    
-// Output: Shared library (.so) for Android 
-apply plugin: 'com.android.library'
 
+// Project's root where CMakeLists.txt exists: rootDir/support/.cxx -> rootDir
+def rootDir = Paths.get(project.buildDir.getParent()).getParent()
+println("rootDir: ${rootDir}")
+
+// Output: Shared library (.so) for Android 
+apply plugin: "com.android.library"
 android {
     compileSdkVersion 25    // Android 7.0
 
@@ -41,13 +43,13 @@ android {
             include  "arm64-v8a", "armeabi-v7a", "x86_64"
         }
     }
+    ndkVersion "21.3.6528147" // ANDROID_NDK_HOME is deprecated. Be explicit
 
     defaultConfig {
         minSdkVersion 21    // Android 5.0+
         targetSdkVersion 25 // Follow Compile SDK
-        versionCode 21      // Follow release count
-        versionName "5.3.0" // Follow Official version
-        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
+        versionCode 34      // Follow release count
+        versionName "7.1.2" // Follow Official version
         
         externalNativeBuild {
             cmake {
@@ -56,9 +58,9 @@ android {
                 arguments "-DFMT_TEST=false"            // Skip test
                 arguments "-DFMT_DOC=false"             // Skip document
                 cppFlags  "-std=c++17"
+                targets   "fmt"
             }
         }
-        println("Gradle CMake Plugin: ")
         println(externalNativeBuild.cmake.cppFlags)
         println(externalNativeBuild.cmake.arguments)
     }
@@ -69,16 +71,27 @@ android {
     //    neighbor of the top level cmake
     externalNativeBuild {
         cmake {
-            path "../CMakeLists.txt"
+            version "3.10.0+"
+            path "${rootDir}/CMakeLists.txt"
             // buildStagingDirectory "./build"  // Custom path for cmake output
         }
-        //println(cmake.path)
     }
     
     sourceSets{
         // Android Manifest for Gradle
         main {
-            manifest.srcFile 'AndroidManifest.xml'
+            manifest.srcFile "AndroidManifest.xml"
+        }
+    }
+
+    // https://developer.android.com/studio/build/native-dependencies#build_system_configuration
+    buildFeatures {
+        prefab true
+        prefabPublishing true
+    }
+    prefab {
+        fmt {
+            headers "${rootDir}/include"
         }
     }
 }
@@ -88,20 +101,32 @@ assemble.doLast
     // Instead of `ninja install`, Gradle will deploy the files.
     // We are doing this since FMT is dependent to the ANDROID_STL after build
     copy {
-        from 'build/intermediates/cmake'
-        into '../libs'
+        from "build/intermediates/cmake"
+        into "${rootDir}/libs"
     }
     // Copy debug binaries
     copy {
-        from '../libs/debug/obj'
-        into '../libs/debug'
+        from "${rootDir}/libs/debug/obj"
+        into "${rootDir}/libs/debug"
     }
     // Copy Release binaries
     copy {
-        from '../libs/release/obj'
-        into '../libs/release'
+        from "${rootDir}/libs/release/obj"
+        into "${rootDir}/libs/release"
     }
     // Remove empty directory
-    delete '../libs/debug/obj'
-    delete '../libs/release/obj'
+    delete "${rootDir}/libs/debug/obj"
+    delete "${rootDir}/libs/release/obj"
+
+    // Copy AAR files. Notice that the aar is named after the folder of this script.
+    copy {
+        from "build/outputs/aar/support-release.aar"
+        into "${rootDir}/libs"
+        rename "support-release.aar", "fmt-release.aar"
+    }
+    copy {
+        from "build/outputs/aar/support-debug.aar"
+        into "${rootDir}/libs"
+        rename "support-debug.aar", "fmt-debug.aar"
+    }
 }

support/cmake/cxx14.cmake

@@ -1,70 +0,0 @@
-# C++14 feature support detection
-
-include(CheckCXXSourceCompiles)
-include(CheckCXXCompilerFlag)
-
-if (NOT CMAKE_CXX_STANDARD)
-  set(CMAKE_CXX_STANDARD 11)
-endif()
-message(STATUS "CXX_STANDARD: ${CMAKE_CXX_STANDARD}")
-
-if (CMAKE_CXX_STANDARD EQUAL 20)
-  check_cxx_compiler_flag(-std=c++20 has_std_20_flag)
-  check_cxx_compiler_flag(-std=c++2a has_std_2a_flag)
-
-  if (has_std_20_flag)
-    set(CXX_STANDARD_FLAG -std=c++20)
-  elseif (has_std_2a_flag)
-    set(CXX_STANDARD_FLAG -std=c++2a)
-  endif ()
-elseif (CMAKE_CXX_STANDARD EQUAL 17)
-  check_cxx_compiler_flag(-std=c++17 has_std_17_flag)
-  check_cxx_compiler_flag(-std=c++1z has_std_1z_flag)
-
-  if (has_std_17_flag)
-    set(CXX_STANDARD_FLAG -std=c++17)
-  elseif (has_std_1z_flag)
-    set(CXX_STANDARD_FLAG -std=c++1z)
-  endif ()
-elseif (CMAKE_CXX_STANDARD EQUAL 14)
-  check_cxx_compiler_flag(-std=c++14 has_std_14_flag)
-  check_cxx_compiler_flag(-std=c++1y has_std_1y_flag)
-
-  if (has_std_14_flag)
-    set(CXX_STANDARD_FLAG -std=c++14)
-  elseif (has_std_1y_flag)
-    set(CXX_STANDARD_FLAG -std=c++1y)
-  endif ()
-elseif (CMAKE_CXX_STANDARD EQUAL 11)
-  check_cxx_compiler_flag(-std=c++11 has_std_11_flag)
-  check_cxx_compiler_flag(-std=c++0x has_std_0x_flag)
-
-  if (has_std_11_flag)
-    set(CXX_STANDARD_FLAG -std=c++11)
-  elseif (has_std_0x_flag)
-    set(CXX_STANDARD_FLAG -std=c++0x)
-  endif ()
-endif ()
-
-set(CMAKE_REQUIRED_FLAGS ${CXX_STANDARD_FLAG})
-
-# Check if user-defined literals are available
-check_cxx_source_compiles("
-  void operator\"\" _udl(long double);
-  int main() {}"
-  SUPPORTS_USER_DEFINED_LITERALS)
-if (NOT SUPPORTS_USER_DEFINED_LITERALS)
-  set (SUPPORTS_USER_DEFINED_LITERALS OFF)
-endif ()
-
-# Check if <variant> is available
-set(CMAKE_REQUIRED_FLAGS -std=c++1z)
-check_cxx_source_compiles("
-  #include <variant>
-  int main() {}"
-  FMT_HAS_VARIANT)
-if (NOT FMT_HAS_VARIANT)
-  set (FMT_HAS_VARIANT OFF)
-endif ()
-
-set(CMAKE_REQUIRED_FLAGS )

support/cmake/fmt-config.cmake.in

@@ -1,4 +1,7 @@
 @PACKAGE_INIT@
 
-include(${CMAKE_CURRENT_LIST_DIR}/@targets_export_name@.cmake)
+if (NOT TARGET fmt::fmt)
+  include(${CMAKE_CURRENT_LIST_DIR}/@targets_export_name@.cmake)
+endif ()
+
 check_required_components(fmt)

support/fmt.pro

@@ -1,27 +0,0 @@
-# Staticlib configuration for qmake builds
-# For some reason qmake 3.1 fails to identify source dependencies and excludes format.cc and printf.cc
-# from compilation so it _MUST_ be called as qmake -nodepend
-# A workaround is implemented below: a custom compiler is defined which does not track dependencies
-
-TEMPLATE = lib
-
-TARGET = fmt
-
-QMAKE_EXT_CPP = .cc
-
-CONFIG = staticlib warn_on c++11
-
-FMT_SOURCES = \
-    ../src/format.cc \
-    ../src/posix.cc
-
-fmt.name = libfmt
-fmt.input = FMT_SOURCES
-fmt.output = ${QMAKE_FILE_BASE}$$QMAKE_EXT_OBJ
-fmt.clean = ${QMAKE_FILE_BASE}$$QMAKE_EXT_OBJ
-fmt.depends = ${QMAKE_FILE_IN}
-# QMAKE_RUN_CXX will not be expanded
-fmt.commands = $$QMAKE_CXX -c $$QMAKE_CXXFLAGS $$QMAKE_CXXFLAGS_WARN_ON $$QMAKE_CXXFLAGS_RELEASE_WITH_DEBUGINFO $$QMAKE_CXXFLAGS_CXX11 ${QMAKE_FILE_IN}
-fmt.variable_out = OBJECTS
-fmt.CONFIG = no_dependencies no_link
-QMAKE_EXTRA_COMPILERS += fmt

support/manage.py

@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 
 """Manage site and releases.
 
@@ -163,6 +163,13 @@ def update_site(env):
                 if version.startswith('7.'):
                     b.data = b.data.replace(', std::size_t', ', size_t')
                     b.data = b.data.replace('join(It, It', 'join(It, Sentinel')
+                if version.startswith('7.1.'):
+                    b.data = b.data.replace(', std::size_t', ', size_t')
+                    b.data = b.data.replace('join(It, It', 'join(It, Sentinel')
+                    b.data = b.data.replace(
+                        'fmt::format_to(OutputIt, const S&, Args&&...)',
+                        'fmt::format_to(OutputIt, const S&, Args&&...) -> ' +
+                        'typename std::enable_if<enable, OutputIt>::type')
                 b.data = b.data.replace('aa long', 'a long')
                 b.data = b.data.replace('serveral', 'several')
                 if version.startswith('6.2.'):
@@ -176,6 +183,12 @@ def update_site(env):
         with rewrite(index) as b:
             b.data = b.data.replace(
                 'doc/latest/index.html#format-string-syntax', 'syntax.html')
+        # Fix issues in syntax.rst.
+        index = os.path.join(target_doc_dir, 'syntax.rst')
+        with rewrite(index) as b:
+            b.data = b.data.replace(
+                '..productionlist:: sf\n', '.. productionlist:: sf\n ')
+            b.data = b.data.replace('Examples:\n', 'Examples::\n')
         # Build the docs.
         html_dir = os.path.join(env.build_dir, 'html')
         if os.path.exists(html_dir):
@@ -233,7 +246,7 @@ def release(args):
     # Update the version in the changelog.
     title_len = 0
     for line in fileinput.input(changelog_path, inplace=True):
-        if line.decode('utf-8').startswith(version + ' - TBD'):
+        if line.startswith(version + ' - TBD'):
             line = version + ' - ' + datetime.date.today().isoformat()
             title_len = len(line)
             line += '\n'
@@ -263,9 +276,9 @@ def release(args):
 
     # Create a release on GitHub.
     fmt_repo.push('origin', 'release')
-    params = {'access_token': os.getenv('FMT_TOKEN')}
+    auth_headers = {'Authorization': 'token ' + os.getenv('FMT_TOKEN')}
     r = requests.post('https://api.github.com/repos/fmtlib/fmt/releases',
-                      params=params,
+                      headers=auth_headers,
                       data=json.dumps({'tag_name': version,
                                        'target_commitish': 'release',
                                        'body': changes, 'draft': True}))
@@ -276,8 +289,8 @@ def release(args):
     package = 'fmt-{}.zip'.format(version)
     r = requests.post(
         '{}/{}/assets?name={}'.format(uploads_url, id, package),
-        headers={'Content-Type': 'application/zip'},
-        params=params, data=open('build/fmt/' + package, 'rb'))
+        headers={'Content-Type': 'application/zip'} | auth_headers,
+        data=open('build/fmt/' + package, 'rb'))
     if r.status_code != 201:
         raise Exception('Failed to upload an asset ' + str(r))
 

support/printable.py

@@ -0,0 +1,201 @@
+#!/usr/bin/env python3
+
+# This script is based on
+# https://github.com/rust-lang/rust/blob/master/library/core/src/unicode/printable.py
+# distributed under https://github.com/rust-lang/rust/blob/master/LICENSE-MIT.
+
+# This script uses the following Unicode tables:
+# - UnicodeData.txt
+
+
+from collections import namedtuple
+import csv
+import os
+import subprocess
+
+NUM_CODEPOINTS=0x110000
+
+def to_ranges(iter):
+    current = None
+    for i in iter:
+        if current is None or i != current[1] or i in (0x10000, 0x20000):
+            if current is not None:
+                yield tuple(current)
+            current = [i, i + 1]
+        else:
+            current[1] += 1
+    if current is not None:
+        yield tuple(current)
+
+def get_escaped(codepoints):
+    for c in codepoints:
+        if (c.class_ or "Cn") in "Cc Cf Cs Co Cn Zl Zp Zs".split() and c.value != ord(' '):
+            yield c.value
+
+def get_file(f):
+    try:
+        return open(os.path.basename(f))
+    except FileNotFoundError:
+        subprocess.run(["curl", "-O", f], check=True)
+        return open(os.path.basename(f))
+
+Codepoint = namedtuple('Codepoint', 'value class_')
+
+def get_codepoints(f):
+    r = csv.reader(f, delimiter=";")
+    prev_codepoint = 0
+    class_first = None
+    for row in r:
+        codepoint = int(row[0], 16)
+        name = row[1]
+        class_ = row[2]
+
+        if class_first is not None:
+            if not name.endswith("Last>"):
+                raise ValueError("Missing Last after First")
+
+        for c in range(prev_codepoint + 1, codepoint):
+            yield Codepoint(c, class_first)
+
+        class_first = None
+        if name.endswith("First>"):
+            class_first = class_
+
+        yield Codepoint(codepoint, class_)
+        prev_codepoint = codepoint
+
+    if class_first is not None:
+        raise ValueError("Missing Last after First")
+
+    for c in range(prev_codepoint + 1, NUM_CODEPOINTS):
+        yield Codepoint(c, None)
+
+def compress_singletons(singletons):
+    uppers = [] # (upper, # items in lowers)
+    lowers = []
+
+    for i in singletons:
+        upper = i >> 8
+        lower = i & 0xff
+        if len(uppers) == 0 or uppers[-1][0] != upper:
+            uppers.append((upper, 1))
+        else:
+            upper, count = uppers[-1]
+            uppers[-1] = upper, count + 1
+        lowers.append(lower)
+
+    return uppers, lowers
+
+def compress_normal(normal):
+    # lengths 0x00..0x7f are encoded as 00, 01, ..., 7e, 7f
+    # lengths 0x80..0x7fff are encoded as 80 80, 80 81, ..., ff fe, ff ff
+    compressed = [] # [truelen, (truelenaux), falselen, (falselenaux)]
+
+    prev_start = 0
+    for start, count in normal:
+        truelen = start - prev_start
+        falselen = count
+        prev_start = start + count
+
+        assert truelen < 0x8000 and falselen < 0x8000
+        entry = []
+        if truelen > 0x7f:
+            entry.append(0x80 | (truelen >> 8))
+            entry.append(truelen & 0xff)
+        else:
+            entry.append(truelen & 0x7f)
+        if falselen > 0x7f:
+            entry.append(0x80 | (falselen >> 8))
+            entry.append(falselen & 0xff)
+        else:
+            entry.append(falselen & 0x7f)
+
+        compressed.append(entry)
+
+    return compressed
+
+def print_singletons(uppers, lowers, uppersname, lowersname):
+    print("  static constexpr singleton {}[] = {{".format(uppersname))
+    for u, c in uppers:
+        print("    {{{:#04x}, {}}},".format(u, c))
+    print("  };")
+    print("  static constexpr unsigned char {}[] = {{".format(lowersname))
+    for i in range(0, len(lowers), 8):
+        print("    {}".format(" ".join("{:#04x},".format(l) for l in lowers[i:i+8])))
+    print("  };")
+
+def print_normal(normal, normalname):
+    print("  static constexpr unsigned char {}[] = {{".format(normalname))
+    for v in normal:
+        print("    {}".format(" ".join("{:#04x},".format(i) for i in v)))
+    print("  };")
+
+def main():
+    file = get_file("https://www.unicode.org/Public/UNIDATA/UnicodeData.txt")
+
+    codepoints = get_codepoints(file)
+
+    CUTOFF=0x10000
+    singletons0 = []
+    singletons1 = []
+    normal0 = []
+    normal1 = []
+    extra = []
+
+    for a, b in to_ranges(get_escaped(codepoints)):
+        if a > 2 * CUTOFF:
+            extra.append((a, b - a))
+        elif a == b - 1:
+            if a & CUTOFF:
+                singletons1.append(a & ~CUTOFF)
+            else:
+                singletons0.append(a)
+        elif a == b - 2:
+            if a & CUTOFF:
+                singletons1.append(a & ~CUTOFF)
+                singletons1.append((a + 1) & ~CUTOFF)
+            else:
+                singletons0.append(a)
+                singletons0.append(a + 1)
+        else:
+            if a >= 2 * CUTOFF:
+                extra.append((a, b - a))
+            elif a & CUTOFF:
+                normal1.append((a & ~CUTOFF, b - a))
+            else:
+                normal0.append((a, b - a))
+
+    singletons0u, singletons0l = compress_singletons(singletons0)
+    singletons1u, singletons1l = compress_singletons(singletons1)
+    normal0 = compress_normal(normal0)
+    normal1 = compress_normal(normal1)
+
+    print("""\
+FMT_FUNC auto is_printable(uint32_t cp) -> bool {\
+""")
+    print_singletons(singletons0u, singletons0l, 'singletons0', 'singletons0_lower')
+    print_singletons(singletons1u, singletons1l, 'singletons1', 'singletons1_lower')
+    print_normal(normal0, 'normal0')
+    print_normal(normal1, 'normal1')
+    print("""\
+  auto lower = static_cast<uint16_t>(cp);
+  if (cp < 0x10000) {
+    return is_printable(lower, singletons0,
+                        sizeof(singletons0) / sizeof(*singletons0),
+                        singletons0_lower, normal0, sizeof(normal0));
+  }
+  if (cp < 0x20000) {
+    return is_printable(lower, singletons1,
+                        sizeof(singletons1) / sizeof(*singletons1),
+                        singletons1_lower, normal1, sizeof(normal1));
+  }\
+""")
+    for a, b in extra:
+        print("  if (0x{:x} <= cp && cp < 0x{:x}) return false;".format(a, a + b))
+    print("""\
+  return cp < 0x{:x};
+}}\
+""".format(NUM_CODEPOINTS))
+
+if __name__ == '__main__':
+    main()

support/rst2md.py

@@ -65,7 +65,7 @@ class Translator(nodes.NodeVisitor):
         self.write('\n\n')
 
     def visit_paragraph(self, node):
-        pass
+        self.write('\n\n')
 
     def depart_paragraph(self, node):
         pass
@@ -138,6 +138,13 @@ class Translator(nodes.NodeVisitor):
     def depart_table(self, node):
         pass
 
+    def visit_system_message(self, node):
+        pass
+
+    def depart_system_message(self, node):
+        pass
+
+
 class MDWriter(writers.Writer):
     """GitHub-flavored markdown writer"""
 

support/travis-build.py

@@ -1,119 +0,0 @@
-#!/usr/bin/env python
-# Build the project on Travis CI.
-
-from __future__ import print_function
-import errno, os, shutil, subprocess, sys, urllib
-from subprocess import call, check_call, Popen, PIPE, STDOUT
-
-def rmtree_if_exists(dir):
-    try:
-        shutil.rmtree(dir)
-    except OSError as e:
-        if e.errno == errno.ENOENT:
-            pass
-
-def makedirs_if_not_exist(dir):
-    try:
-        os.makedirs(dir)
-    except OSError as e:
-        if e.errno != errno.EEXIST:
-            raise
-
-def install_dependencies():
-    branch = os.environ['TRAVIS_BRANCH']
-    if branch != 'master':
-        print('Branch: ' + branch)
-        exit(0) # Ignore non-master branches
-    check_call('curl -s https://deb.nodesource.com/gpgkey/nodesource.gpg.key ' +
-               '| sudo apt-key add -', shell=True)
-    check_call('echo "deb https://deb.nodesource.com/node_0.10 precise main" ' +
-               '| sudo tee /etc/apt/sources.list.d/nodesource.list', shell=True)
-    check_call(['sudo', 'apt-get', 'update'])
-    check_call(['sudo', 'apt-get', 'install', 'python-virtualenv', 'nodejs'])
-    check_call(['sudo', 'npm', 'install', '-g', 'less@2.6.1', 'less-plugin-clean-css'])
-    deb_file = 'doxygen_1.8.6-2_amd64.deb'
-    urllib.urlretrieve('http://mirrors.kernel.org/ubuntu/pool/main/d/doxygen/' +
-                       deb_file, deb_file)
-    check_call(['sudo', 'dpkg', '-i', deb_file])
-
-fmt_dir = os.path.dirname(os.path.dirname(os.path.realpath(__file__)))
-
-build = os.environ['BUILD']
-if build == 'Doc':
-    travis = 'TRAVIS' in os.environ
-    if travis:
-        install_dependencies()
-    sys.path.insert(0, os.path.join(fmt_dir, 'doc'))
-    import build
-    build.create_build_env()
-    html_dir = build.build_docs()
-    repo = 'fmtlib.github.io'
-    if travis and 'KEY' not in os.environ:
-        # Don't update the repo if building on Travis from an account that
-        # doesn't have push access.
-        print('Skipping update of ' + repo)
-        exit(0)
-    # Clone the fmtlib.github.io repo.
-    rmtree_if_exists(repo)
-    git_url = 'https://github.com/' if travis else 'git@github.com:'
-    check_call(['git', 'clone', git_url + 'fmtlib/{}.git'.format(repo)])
-    # Copy docs to the repo.
-    target_dir = os.path.join(repo, 'dev')
-    rmtree_if_exists(target_dir)
-    shutil.copytree(html_dir, target_dir, ignore=shutil.ignore_patterns('.*'))
-    if travis:
-        check_call(['git', 'config', '--global', 'user.name', 'amplbot'])
-        check_call(['git', 'config', '--global', 'user.email', 'viz@ampl.com'])
-    # Push docs to GitHub pages.
-    check_call(['git', 'add', '--all'], cwd=repo)
-    if call(['git', 'diff-index', '--quiet', 'HEAD'], cwd=repo):
-        check_call(['git', 'commit', '-m', 'Update documentation'], cwd=repo)
-        cmd = 'git push'
-        if travis:
-            cmd += ' https://$KEY@github.com/fmtlib/fmtlib.github.io.git master'
-        p = Popen(cmd, shell=True, stdout=PIPE, stderr=STDOUT, cwd=repo)
-        # Print the output without the key.
-        print(p.communicate()[0].replace(os.environ['KEY'], '$KEY'))
-        if p.returncode != 0:
-            raise subprocess.CalledProcessError(p.returncode, cmd)
-    exit(0)
-
-standard = os.environ['STANDARD']
-install_dir    = os.path.join(fmt_dir, "_install")
-build_dir      = os.path.join(fmt_dir, "_build")
-test_build_dir = os.path.join(fmt_dir, "_build_test")
-
-# Configure the library.
-makedirs_if_not_exist(build_dir)
-cmake_flags = [
-    '-DCMAKE_INSTALL_PREFIX=' + install_dir, '-DCMAKE_BUILD_TYPE=' + build,
-    '-DCMAKE_CXX_STANDARD=' + standard
-]
-
-# Make sure the fuzzers still compile.
-main_cmake_flags = list(cmake_flags)
-if 'ENABLE_FUZZING' in os.environ:
-    main_cmake_flags += ['-DFMT_FUZZ=ON', '-DFMT_FUZZ_LINKMAIN=On']
-
-check_call(['cmake', '-DFMT_DOC=OFF', '-DFMT_PEDANTIC=ON', '-DFMT_WERROR=ON', fmt_dir] +
-           main_cmake_flags, cwd=build_dir)
-
-# Build the library.
-check_call(['cmake', '--build','.'], cwd=build_dir)
-
-# Test the library.
-env = os.environ.copy()
-env['CTEST_OUTPUT_ON_FAILURE'] = '1'
-if call(['make', 'test'], env=env, cwd=build_dir):
-    with open(os.path.join(build_dir, 'Testing', 'Temporary', 'LastTest.log'), 'r') as f:
-        print(f.read())
-    sys.exit(-1)
-
-# Install the library.
-check_call(['make', 'install'], cwd=build_dir)
-
-# Test installation.
-makedirs_if_not_exist(test_build_dir)
-check_call(['cmake', os.path.join(fmt_dir, "test", "find-package-test")] +
-            cmake_flags, cwd=test_build_dir)
-check_call(['make', '-j4'], cwd=test_build_dir)

support/update-coverity-branch.py

@@ -1,30 +0,0 @@
-#!/usr/bin/env python
-# Update the coverity branch from the master branch.
-# It is not done automatically because Coverity Scan limits
-# the number of submissions per day.
-
-from __future__ import print_function
-import shutil, tempfile
-from subprocess import check_output, STDOUT
-
-class Git:
-    def __init__(self, dir):
-        self.dir = dir
-
-    def __call__(self, *args):
-        output = check_output(['git'] + list(args), cwd=self.dir, stderr=STDOUT)
-        print(output)
-        return output
-
-dir = tempfile.mkdtemp()
-try:
-    git = Git(dir)
-    git('clone', '-b', 'coverity', 'git@github.com:fmtlib/fmt.git', dir)
-    output = git('merge', '-X', 'theirs', '--no-commit', 'origin/master')
-    if 'Fast-forward' not in output:
-        git('reset', 'HEAD', '.travis.yml')
-        git('checkout', '--', '.travis.yml')
-        git('commit', '-m', 'Update coverity branch')
-    git('push')
-finally:
-    shutil.rmtree(dir)

test/CMakeLists.txt

@@ -1,80 +1,49 @@
-#------------------------------------------------------------------------------
-# Build the google test library
+add_subdirectory(gtest)
 
-# We compile Google Test ourselves instead of using pre-compiled libraries.
-# See the Google Test FAQ "Why is it not recommended to install a
-# pre-compiled copy of Google Test (for example, into /usr/local)?"
-# at http://code.google.com/p/googletest/wiki/FAQ for more details.
-add_library(gmock STATIC
-  gmock-gtest-all.cc gmock/gmock.h gtest/gtest.h gtest/gtest-spi.h)
-target_compile_definitions(gmock PUBLIC GTEST_HAS_STD_WSTRING=1)
-target_include_directories(gmock SYSTEM PUBLIC . gmock gtest)
-
-find_package(Threads)
-if (Threads_FOUND)
-  target_link_libraries(gmock ${CMAKE_THREAD_LIBS_INIT})
-else ()
-  target_compile_definitions(gmock PUBLIC GTEST_HAS_PTHREAD=0)
-endif ()
-
-target_compile_definitions(gmock PUBLIC GTEST_LANG_CXX11=0)
-
-if (MSVC)
-  # Workaround a bug in implementation of variadic templates in MSVC11.
-  target_compile_definitions(gmock PUBLIC _VARIADIC_MAX=10)
-  
-  # Disable MSVC warnings of _CRT_INSECURE_DEPRECATE functions.
-  target_compile_definitions(gmock PRIVATE _CRT_SECURE_NO_WARNINGS)
-  if (CMAKE_CXX_COMPILER_ID MATCHES "Clang")
-    # Disable MSVC warnings of POSIX functions.
-    target_compile_options(gmock PUBLIC -Wno-deprecated-declarations)
-  endif ()
-endif ()
-
-# GTest doesn't detect <tuple> with clang.
-if (CMAKE_CXX_COMPILER_ID STREQUAL "Clang")
-  target_compile_definitions(gmock PUBLIC GTEST_USE_OWN_TR1_TUPLE=1)
-endif ()
-
-# Silence MSVC tr1 deprecation warning in gmock.
-target_compile_definitions(gmock
-  PUBLIC _SILENCE_TR1_NAMESPACE_DEPRECATION_WARNING=1)
-
-#------------------------------------------------------------------------------
-# Build the actual library tests
+include(CheckSymbolExists)
 
 set(TEST_MAIN_SRC test-main.cc gtest-extra.cc gtest-extra.h util.cc)
 add_library(test-main STATIC ${TEST_MAIN_SRC})
-target_include_directories(test-main SYSTEM PUBLIC gtest gmock)
-target_link_libraries(test-main gmock fmt)
-
-include(CheckCXXCompilerFlag)
-
-# Workaround GTest bug https://github.com/google/googletest/issues/705.
-check_cxx_compiler_flag(
-  -fno-delete-null-pointer-checks HAVE_FNO_DELETE_NULL_POINTER_CHECKS)
-if (HAVE_FNO_DELETE_NULL_POINTER_CHECKS)
-  target_compile_options(test-main PUBLIC -fno-delete-null-pointer-checks)
-endif ()
-
-# Use less strict pedantic flags for the tests because GMock doesn't compile
-# cleanly with -pedantic and -std=c++98.
-if (CMAKE_COMPILER_IS_GNUCXX OR (CMAKE_CXX_COMPILER_ID MATCHES "Clang"))
-    #set(PEDANTIC_COMPILE_FLAGS -Wall -Wextra -Wno-long-long -Wno-variadic-macros)
-endif ()
+target_include_directories(test-main PUBLIC
+  $<BUILD_INTERFACE:${PROJECT_SOURCE_DIR}/include>)
+target_link_libraries(test-main gtest fmt)
 
 function(add_fmt_executable name)
   add_executable(${name} ${ARGN})
-  if (MINGW)
-    target_link_libraries(${name} -static-libgcc -static-libstdc++)
+  # (Wstringop-overflow) - [meta-bug] bogus/missing -Wstringop-overflow warnings
+  #   https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88443
+  # Bogus -Wstringop-overflow warning
+  #   https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100395
+  # [10 Regression] spurious -Wstringop-overflow writing to a trailing array plus offset
+  #   https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95353
+  if (CMAKE_CXX_COMPILER_ID MATCHES "GNU" AND
+      NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS 7.0)
+    target_compile_options(${name} PRIVATE -Wno-stringop-overflow)
+    # The linker flag is needed for LTO.
+    target_link_libraries(${name} -Wno-stringop-overflow)
   endif ()
 endfunction()
 
 # Adds a test.
 # Usage: add_fmt_test(name srcs...)
 function(add_fmt_test name)
-  add_fmt_executable(${name} ${name}.cc ${ARGN})
-  target_link_libraries(${name} test-main)
+  cmake_parse_arguments(ADD_FMT_TEST "HEADER_ONLY;MODULE" "" "" ${ARGN})
+
+  set(sources ${name}.cc ${ADD_FMT_TEST_UNPARSED_ARGUMENTS})
+  if (ADD_FMT_TEST_HEADER_ONLY)
+    set(sources ${sources} ${TEST_MAIN_SRC} ../src/os.cc)
+    set(libs gtest fmt-header-only)
+    if (CMAKE_CXX_COMPILER_ID MATCHES "Clang")
+      set(PEDANTIC_COMPILE_FLAGS ${PEDANTIC_COMPILE_FLAGS} -Wno-weak-vtables)
+    endif ()
+  elseif (ADD_FMT_TEST_MODULE)
+    set(libs test-main test-module)
+    set_source_files_properties(${name}.cc PROPERTIES OBJECT_DEPENDS test-module)
+  else ()
+    set(libs test-main fmt)
+  endif ()
+  add_fmt_executable(${name} ${sources})
+  target_link_libraries(${name} ${libs})
 
   # Define if certain C++ features can be used.
   if (FMT_PEDANTIC)
@@ -83,83 +52,118 @@ function(add_fmt_test name)
   if (FMT_WERROR)
     target_compile_options(${name} PRIVATE ${WERROR_FLAG})
   endif ()
-  target_include_directories(${name} SYSTEM PUBLIC gtest gmock)
   add_test(NAME ${name} COMMAND ${name})
 endfunction()
 
+if (FMT_MODULE)
+  return ()
+endif ()
+
+add_fmt_test(args-test)
 add_fmt_test(assert-test)
 add_fmt_test(chrono-test)
 add_fmt_test(color-test)
 add_fmt_test(core-test)
-add_fmt_test(grisu-test)
-target_compile_definitions(grisu-test PRIVATE FMT_USE_GRISU=1)
 add_fmt_test(gtest-extra-test)
 add_fmt_test(format-test mock-allocator.h)
 if (MSVC)
   target_compile_options(format-test PRIVATE /bigobj)
 endif ()
 if (NOT (MSVC AND BUILD_SHARED_LIBS))
-  add_fmt_test(format-impl-test)
+  add_fmt_test(format-impl-test HEADER_ONLY header-only-test.cc)
 endif ()
-add_fmt_test(locale-test)
 add_fmt_test(ostream-test)
 add_fmt_test(compile-test)
+add_fmt_test(compile-fp-test HEADER_ONLY)
+if (MSVC)
+  # Without this option, MSVC returns 199711L for the __cplusplus macro.
+  target_compile_options(compile-fp-test PRIVATE /Zc:__cplusplus)
+endif()
 add_fmt_test(printf-test)
-add_fmt_test(custom-formatter-test)
-add_fmt_test(ranges-test)
-add_fmt_test(scan-test)
+add_fmt_test(ranges-test ranges-odr-test.cc)
 
-if (NOT MSVC_BUILD_STATIC)
+add_fmt_test(scan-test)
+check_symbol_exists(strptime "time.h" HAVE_STRPTIME)
+if (HAVE_STRPTIME)
+  target_compile_definitions(scan-test PRIVATE FMT_HAVE_STRPTIME)
+endif ()
+
+add_fmt_test(std-test)
+try_compile(compile_result_unused
+            ${CMAKE_CURRENT_BINARY_DIR}
+            SOURCES ${CMAKE_CURRENT_LIST_DIR}/detect-stdfs.cc
+            OUTPUT_VARIABLE RAWOUTPUT)
+string(REGEX REPLACE ".*libfound \"([^\"]*)\".*" "\\1" STDLIBFS "${RAWOUTPUT}")
+if (STDLIBFS)
+  target_link_libraries(std-test ${STDLIBFS})
+endif ()
+add_fmt_test(unicode-test HEADER_ONLY)
+if (MSVC)
+  target_compile_options(unicode-test PRIVATE /utf-8)
+endif ()
+add_fmt_test(xchar-test)
+add_fmt_test(enforce-checks-test)
+target_compile_definitions(enforce-checks-test PRIVATE
+                           -DFMT_ENFORCE_COMPILE_STRING)
+
+if (FMT_MODULE)
+  # The tests need {fmt} to be compiled as traditional library
+  # because of visibility of implementation details.
+  # If module support is present the module tests require a
+  # test-only module to be built from {fmt}
+  add_library(test-module OBJECT ${CMAKE_SOURCE_DIR}/src/fmt.cc)
+  target_compile_features(test-module PUBLIC cxx_std_11)
+  target_include_directories(test-module PUBLIC
+    $<BUILD_INTERFACE:${PROJECT_SOURCE_DIR}/include>)
+  enable_module(test-module)
+
+  add_fmt_test(module-test MODULE test-main.cc)
+  if (MSVC)
+    target_compile_options(test-module PRIVATE /utf-8 /Zc:__cplusplus
+                           /Zc:externConstexpr /Zc:inline)
+    target_compile_options(module-test PRIVATE /utf-8 /Zc:__cplusplus
+                           /Zc:externConstexpr /Zc:inline)
+  endif ()
+endif ()
+
+if (NOT DEFINED MSVC_STATIC_RUNTIME AND MSVC)
+  foreach (flag_var
+			 CMAKE_CXX_FLAGS CMAKE_CXX_FLAGS_DEBUG CMAKE_CXX_FLAGS_RELEASE
+			 CMAKE_CXX_FLAGS_MINSIZEREL CMAKE_CXX_FLAGS_RELWITHDEBINFO)
+	if (${flag_var} MATCHES "^(/|-)(MT|MTd)")
+	  set(MSVC_STATIC_RUNTIME ON)
+	  break()
+	endif()
+  endforeach()
+endif()
+
+if (NOT MSVC_STATIC_RUNTIME)
   add_fmt_executable(posix-mock-test
     posix-mock-test.cc ../src/format.cc ${TEST_MAIN_SRC})
   target_include_directories(
     posix-mock-test PRIVATE ${PROJECT_SOURCE_DIR}/include)
-  target_link_libraries(posix-mock-test gmock)
-  target_include_directories(posix-mock-test SYSTEM PUBLIC gtest gmock)
+  target_link_libraries(posix-mock-test gtest)
   if (FMT_PEDANTIC)
     target_compile_options(posix-mock-test PRIVATE ${PEDANTIC_COMPILE_FLAGS})
   endif ()
-  if (HAVE_STRTOD_L)
-    target_compile_definitions(posix-mock-test PRIVATE FMT_LOCALE)
-  endif ()
   add_test(NAME posix-mock-test COMMAND posix-mock-test)
   add_fmt_test(os-test)
 endif ()
 
-add_fmt_executable(header-only-test
-  header-only-test.cc header-only-test2.cc test-main.cc)
-target_link_libraries(header-only-test gmock)
-target_include_directories(header-only-test SYSTEM PUBLIC gtest gmock)
-if (TARGET fmt-header-only)
-  target_link_libraries(header-only-test fmt-header-only)
-else ()
-  target_include_directories(
-    header-only-test PRIVATE ${PROJECT_SOURCE_DIR}/include)
-  target_compile_definitions(header-only-test PRIVATE FMT_HEADER_ONLY=1)
-endif ()
-
 message(STATUS "FMT_PEDANTIC: ${FMT_PEDANTIC}")
 
 if (FMT_PEDANTIC)
-  # MSVC fails to compile GMock when C++17 is enabled.
-  if (FMT_HAS_VARIANT AND NOT MSVC)
-    add_fmt_test(std-format-test)
-    set_property(TARGET std-format-test PROPERTY CXX_STANDARD 17)
-  endif ()
-
   # Test that the library can be compiled with exceptions disabled.
   # -fno-exception is broken in icc: https://github.com/fmtlib/fmt/issues/822.
   if (NOT CMAKE_CXX_COMPILER_ID STREQUAL "Intel")
     check_cxx_compiler_flag(-fno-exceptions HAVE_FNO_EXCEPTIONS_FLAG)
   endif ()
   if (HAVE_FNO_EXCEPTIONS_FLAG)
-    add_library(noexception-test ../src/format.cc)
+    add_library(noexception-test ../src/format.cc noexception-test.cc)
     target_include_directories(
       noexception-test PRIVATE ${PROJECT_SOURCE_DIR}/include)
     target_compile_options(noexception-test PRIVATE -fno-exceptions)
-    if (FMT_PEDANTIC)
-      target_compile_options(noexception-test PRIVATE ${PEDANTIC_COMPILE_FLAGS})
-    endif ()
+    target_compile_options(noexception-test PRIVATE ${PEDANTIC_COMPILE_FLAGS})
   endif ()
 
   # Test that the library compiles without locale.
@@ -168,7 +172,11 @@ if (FMT_PEDANTIC)
     nolocale-test PRIVATE ${PROJECT_SOURCE_DIR}/include)
   target_compile_definitions(
     nolocale-test PRIVATE FMT_STATIC_THOUSANDS_SEPARATOR=1)
+endif ()
 
+# These tests are disabled on Windows because they take too long.
+if (FMT_PEDANTIC AND NOT WIN32)
+  # Test if incorrect API usages produce compilation error.
   add_test(compile-error-test ${CMAKE_CTEST_COMMAND}
     --build-and-test
     "${CMAKE_CURRENT_SOURCE_DIR}/compile-error-test"
@@ -177,14 +185,11 @@ if (FMT_PEDANTIC)
     --build-makeprogram ${CMAKE_MAKE_PROGRAM}
     --build-options
     "-DCMAKE_CXX_COMPILER=${CMAKE_CXX_COMPILER}"
+    "-DCMAKE_CXX_FLAGS=${CMAKE_CXX_FLAGS}"
     "-DCMAKE_CXX_STANDARD=${CMAKE_CXX_STANDARD}"
     "-DCXX_STANDARD_FLAG=${CXX_STANDARD_FLAG}"
-    "-DPEDANTIC_COMPILE_FLAGS=${PEDANTIC_COMPILE_FLAGS}"
-    "-DSUPPORTS_USER_DEFINED_LITERALS=${SUPPORTS_USER_DEFINED_LITERALS}")
-endif ()
+    "-DFMT_DIR=${CMAKE_SOURCE_DIR}")
 
-# These tests are disabled on Windows because they take too long.
-if (FMT_PEDANTIC AND NOT WIN32)
   # Test if the targets are found from the build directory.
   add_test(find-package-test ${CMAKE_CTEST_COMMAND}
     -C ${CMAKE_BUILD_TYPE}
@@ -195,6 +200,7 @@ if (FMT_PEDANTIC AND NOT WIN32)
     --build-makeprogram ${CMAKE_MAKE_PROGRAM}
     --build-options
     "-DCMAKE_CXX_COMPILER=${CMAKE_CXX_COMPILER}"
+    "-DCMAKE_CXX_FLAGS=${CMAKE_CXX_FLAGS}"
     "-DCMAKE_CXX_STANDARD=${CMAKE_CXX_STANDARD}"
     "-DFMT_DIR=${PROJECT_BINARY_DIR}"
     "-DPEDANTIC_COMPILE_FLAGS=${PEDANTIC_COMPILE_FLAGS}"
@@ -215,6 +221,21 @@ if (FMT_PEDANTIC AND NOT WIN32)
     "-DCMAKE_BUILD_TYPE=${CMAKE_BUILD_TYPE}")
 endif ()
 
+# This test are disabled on Windows because it is only *NIX issue.
+if (FMT_PEDANTIC AND NOT WIN32)
+  add_test(static-export-test ${CMAKE_CTEST_COMMAND}
+    -C ${CMAKE_BUILD_TYPE}
+    --build-and-test
+    "${CMAKE_CURRENT_SOURCE_DIR}/static-export-test"
+    "${CMAKE_CURRENT_BINARY_DIR}/static-export-test"
+    --build-generator ${CMAKE_GENERATOR}
+    --build-makeprogram ${CMAKE_MAKE_PROGRAM}
+    --build-options
+    "-DCMAKE_CXX_COMPILER=${CMAKE_CXX_COMPILER}"
+    "-DCMAKE_CXX_STANDARD=${CMAKE_CXX_STANDARD}"
+    "-DCMAKE_BUILD_TYPE=${CMAKE_BUILD_TYPE}")
+endif ()
+
 # Activate optional CUDA tests if CUDA is found. For version selection see
 # https://docs.nvidia.com/cuda/cuda-c-programming-guide/index.html#cpp14-language-features
 if (FMT_CUDA_TEST)

test/add-subdirectory-test/CMakeLists.txt

@@ -1,17 +1,17 @@
-cmake_minimum_required(VERSION 3.1.0)
+cmake_minimum_required(VERSION 3.8...3.25)
 
-project(fmt-test)
+project(fmt-test CXX)
 
 add_subdirectory(../.. fmt)
 
-add_executable(library-test "main.cc")
-target_link_libraries(library-test fmt::fmt)
-target_compile_options(library-test PRIVATE ${PEDANTIC_COMPILE_FLAGS})
+add_executable(library-test main.cc)
 target_include_directories(library-test PUBLIC SYSTEM .)
+target_compile_options(library-test PRIVATE ${PEDANTIC_COMPILE_FLAGS})
+target_link_libraries(library-test fmt::fmt)
 
 if (TARGET fmt::fmt-header-only)
-  add_executable(header-only-test "main.cc")
-  target_link_libraries(header-only-test fmt::fmt-header-only)
-  target_compile_options(header-only-test PRIVATE ${PEDANTIC_COMPILE_FLAGS})
+  add_executable(header-only-test main.cc)
   target_include_directories(header-only-test PUBLIC SYSTEM .)
+  target_compile_options(header-only-test PRIVATE ${PEDANTIC_COMPILE_FLAGS})
+  target_link_libraries(header-only-test fmt::fmt-header-only)
 endif ()

test/add-subdirectory-test/main.cc

@@ -1,6 +1,5 @@
-#include "fmt/format.h"
+#include "fmt/core.h"
 
 int main(int argc, char** argv) {
-  for(int i = 0; i < argc; ++i)
-    fmt::print("{}: {}\n", i, argv[i]);
+  for (int i = 0; i < argc; ++i) fmt::print("{}: {}\n", i, argv[i]);
 }

test/args-test.cc

@@ -0,0 +1,186 @@
+// Formatting library for C++ - dynamic argument store tests
+//
+// Copyright (c) 2012 - present, Victor Zverovich
+// All rights reserved.
+//
+// For the license information refer to format.h.
+
+#include "fmt/args.h"
+
+#include <memory>
+
+#include "gtest/gtest.h"
+
+TEST(args_test, basic) {
+  fmt::dynamic_format_arg_store<fmt::format_context> store;
+  store.push_back(42);
+  store.push_back("abc1");
+  store.push_back(1.5f);
+  EXPECT_EQ("42 and abc1 and 1.5", fmt::vformat("{} and {} and {}", store));
+}
+
+TEST(args_test, strings_and_refs) {
+  // Unfortunately the tests are compiled with old ABI so strings use COW.
+  fmt::dynamic_format_arg_store<fmt::format_context> store;
+  char str[] = "1234567890";
+  store.push_back(str);
+  store.push_back(std::cref(str));
+  store.push_back(fmt::string_view{str});
+  str[0] = 'X';
+
+  auto result = fmt::vformat("{} and {} and {}", store);
+  EXPECT_EQ("1234567890 and X234567890 and X234567890", result);
+}
+
+struct custom_type {
+  int i = 0;
+};
+
+FMT_BEGIN_NAMESPACE
+template <> struct formatter<custom_type> {
+  auto parse(format_parse_context& ctx) const -> decltype(ctx.begin()) {
+    return ctx.begin();
+  }
+
+  template <typename FormatContext>
+  auto format(const custom_type& p, FormatContext& ctx) -> decltype(ctx.out()) {
+    return fmt::format_to(ctx.out(), "cust={}", p.i);
+  }
+};
+FMT_END_NAMESPACE
+
+TEST(args_test, custom_format) {
+  fmt::dynamic_format_arg_store<fmt::format_context> store;
+  auto c = custom_type();
+  store.push_back(c);
+  ++c.i;
+  store.push_back(c);
+  ++c.i;
+  store.push_back(std::cref(c));
+  ++c.i;
+  auto result = fmt::vformat("{} and {} and {}", store);
+  EXPECT_EQ("cust=0 and cust=1 and cust=3", result);
+}
+
+struct to_stringable {
+  friend fmt::string_view to_string_view(to_stringable) { return {}; }
+};
+
+FMT_BEGIN_NAMESPACE
+template <> struct formatter<to_stringable> {
+  auto parse(format_parse_context& ctx) const -> decltype(ctx.begin()) {
+    return ctx.begin();
+  }
+
+  auto format(to_stringable, format_context& ctx) -> decltype(ctx.out()) {
+    return ctx.out();
+  }
+};
+FMT_END_NAMESPACE
+
+TEST(args_test, to_string_and_formatter) {
+  fmt::dynamic_format_arg_store<fmt::format_context> store;
+  auto s = to_stringable();
+  store.push_back(s);
+  store.push_back(std::cref(s));
+  fmt::vformat("", store);
+}
+
+TEST(args_test, named_int) {
+  fmt::dynamic_format_arg_store<fmt::format_context> store;
+  store.push_back(fmt::arg("a1", 42));
+  EXPECT_EQ("42", fmt::vformat("{a1}", store));
+}
+
+TEST(args_test, named_strings) {
+  fmt::dynamic_format_arg_store<fmt::format_context> store;
+  char str[] = "1234567890";
+  store.push_back(fmt::arg("a1", str));
+  store.push_back(fmt::arg("a2", std::cref(str)));
+  str[0] = 'X';
+  EXPECT_EQ("1234567890 and X234567890", fmt::vformat("{a1} and {a2}", store));
+}
+
+TEST(args_test, named_arg_by_ref) {
+  fmt::dynamic_format_arg_store<fmt::format_context> store;
+  char band[] = "Rolling Stones";
+  store.push_back(fmt::arg("band", std::cref(band)));
+  band[9] = 'c';  // Changing band affects the output.
+  EXPECT_EQ(fmt::vformat("{band}", store), "Rolling Scones");
+}
+
+TEST(args_test, named_custom_format) {
+  fmt::dynamic_format_arg_store<fmt::format_context> store;
+  auto c = custom_type();
+  store.push_back(fmt::arg("c1", c));
+  ++c.i;
+  store.push_back(fmt::arg("c2", c));
+  ++c.i;
+  store.push_back(fmt::arg("c_ref", std::cref(c)));
+  ++c.i;
+  auto result = fmt::vformat("{c1} and {c2} and {c_ref}", store);
+  EXPECT_EQ("cust=0 and cust=1 and cust=3", result);
+}
+
+TEST(args_test, clear) {
+  fmt::dynamic_format_arg_store<fmt::format_context> store;
+  store.push_back(42);
+
+  auto result = fmt::vformat("{}", store);
+  EXPECT_EQ("42", result);
+
+  store.push_back(43);
+  result = fmt::vformat("{} and {}", store);
+  EXPECT_EQ("42 and 43", result);
+
+  store.clear();
+  store.push_back(44);
+  result = fmt::vformat("{}", store);
+  EXPECT_EQ("44", result);
+}
+
+TEST(args_test, reserve) {
+  fmt::dynamic_format_arg_store<fmt::format_context> store;
+  store.reserve(2, 1);
+  store.push_back(1.5f);
+  store.push_back(fmt::arg("a1", 42));
+  auto result = fmt::vformat("{a1} and {}", store);
+  EXPECT_EQ("42 and 1.5", result);
+}
+
+struct copy_throwable {
+  copy_throwable() {}
+  copy_throwable(const copy_throwable&) { throw "deal with it"; }
+};
+
+FMT_BEGIN_NAMESPACE
+template <> struct formatter<copy_throwable> {
+  auto parse(format_parse_context& ctx) const -> decltype(ctx.begin()) {
+    return ctx.begin();
+  }
+  auto format(copy_throwable, format_context& ctx) -> decltype(ctx.out()) {
+    return ctx.out();
+  }
+};
+FMT_END_NAMESPACE
+
+TEST(args_test, throw_on_copy) {
+  fmt::dynamic_format_arg_store<fmt::format_context> store;
+  store.push_back(std::string("foo"));
+  try {
+    store.push_back(copy_throwable());
+  } catch (...) {
+  }
+  EXPECT_EQ(fmt::vformat("{}", store), "foo");
+}
+
+TEST(args_test, move_constructor) {
+  using store_type = fmt::dynamic_format_arg_store<fmt::format_context>;
+  auto store = std::unique_ptr<store_type>(new store_type());
+  store->push_back(42);
+  store->push_back(std::string("foo"));
+  store->push_back(fmt::arg("a1", "foo"));
+  auto moved_store = std::move(*store);
+  store.reset();
+  EXPECT_EQ(fmt::vformat("{} {} {a1}", moved_store), "42 foo foo");
+}

test/assert-test.cc

@@ -1,4 +1,8 @@
-// Formatting library for C++ - assertion tests
+// Formatting library for C++ - FMT_ASSERT test
+//
+// It is a separate test to minimize the number of EXPECT_DEBUG_DEATH checks
+// which are slow on some platforms. In other tests FMT_ASSERT is made to throw
+// an exception which is much faster and easier to check.
 //
 // Copyright (c) 2012 - present, Victor Zverovich
 // All rights reserved.
@@ -6,9 +10,9 @@
 // For the license information refer to format.h.
 
 #include "fmt/core.h"
-#include "gtest.h"
+#include "gtest/gtest.h"
 
-TEST(AssertTest, Fail) {
+TEST(assert_test, fail) {
 #if GTEST_HAS_DEATH_TEST
   EXPECT_DEBUG_DEATH(FMT_ASSERT(false, "don't panic!"), "don't panic!");
 #else
@@ -16,9 +20,8 @@ TEST(AssertTest, Fail) {
 #endif
 }
 
-bool test_condition = false;
-
-TEST(AssertTest, DanglingElse) {
+TEST(assert_test, dangling_else) {
+  bool test_condition = false;
   bool executed_else = false;
   if (test_condition)
     FMT_ASSERT(true, "");

test/color-test.cc

@@ -7,62 +7,29 @@
 
 #include "fmt/color.h"
 
-#include "gtest-extra.h"
+#include <iterator>  // std::back_inserter
 
-TEST(ColorsTest, ColorsPrint) {
-  EXPECT_WRITE(stdout, fmt::print(fg(fmt::rgb(255, 20, 30)), "rgb(255,20,30)"),
-               "\x1b[38;2;255;020;030mrgb(255,20,30)\x1b[0m");
-  EXPECT_WRITE(stdout, fmt::print(fg(fmt::color::blue), "blue"),
-               "\x1b[38;2;000;000;255mblue\x1b[0m");
-  EXPECT_WRITE(
-      stdout,
-      fmt::print(fg(fmt::color::blue) | bg(fmt::color::red), "two color"),
-      "\x1b[38;2;000;000;255m\x1b[48;2;255;000;000mtwo color\x1b[0m");
-  EXPECT_WRITE(stdout, fmt::print(fmt::emphasis::bold, "bold"),
-               "\x1b[1mbold\x1b[0m");
-  EXPECT_WRITE(stdout, fmt::print(fmt::emphasis::italic, "italic"),
-               "\x1b[3mitalic\x1b[0m");
-  EXPECT_WRITE(stdout, fmt::print(fmt::emphasis::underline, "underline"),
-               "\x1b[4munderline\x1b[0m");
-  EXPECT_WRITE(stdout,
-               fmt::print(fmt::emphasis::strikethrough, "strikethrough"),
-               "\x1b[9mstrikethrough\x1b[0m");
-  EXPECT_WRITE(
-      stdout,
-      fmt::print(fg(fmt::color::blue) | fmt::emphasis::bold, "blue/bold"),
-      "\x1b[1m\x1b[38;2;000;000;255mblue/bold\x1b[0m");
-  EXPECT_WRITE(stderr, fmt::print(stderr, fmt::emphasis::bold, "bold error"),
-               "\x1b[1mbold error\x1b[0m");
-  EXPECT_WRITE(stderr, fmt::print(stderr, fg(fmt::color::blue), "blue log"),
-               "\x1b[38;2;000;000;255mblue log\x1b[0m");
-  EXPECT_WRITE(stdout, fmt::print(fmt::text_style(), "hi"), "hi");
-  EXPECT_WRITE(stdout, fmt::print(fg(fmt::terminal_color::red), "tred"),
-               "\x1b[31mtred\x1b[0m");
-  EXPECT_WRITE(stdout, fmt::print(bg(fmt::terminal_color::cyan), "tcyan"),
-               "\x1b[46mtcyan\x1b[0m");
-  EXPECT_WRITE(stdout,
-               fmt::print(fg(fmt::terminal_color::bright_green), "tbgreen"),
-               "\x1b[92mtbgreen\x1b[0m");
-  EXPECT_WRITE(stdout,
-               fmt::print(bg(fmt::terminal_color::bright_magenta), "tbmagenta"),
-               "\x1b[105mtbmagenta\x1b[0m");
-}
+#include "gtest-extra.h"  // EXPECT_WRITE
 
-TEST(ColorsTest, Format) {
+TEST(color_test, format) {
   EXPECT_EQ(fmt::format(fg(fmt::rgb(255, 20, 30)), "rgb(255,20,30)"),
             "\x1b[38;2;255;020;030mrgb(255,20,30)\x1b[0m");
-  EXPECT_EQ(fmt::format(fg(fmt::rgb(255, 20, 30)), L"rgb(255,20,30) wide"),
-            L"\x1b[38;2;255;020;030mrgb(255,20,30) wide\x1b[0m");
   EXPECT_EQ(fmt::format(fg(fmt::color::blue), "blue"),
             "\x1b[38;2;000;000;255mblue\x1b[0m");
   EXPECT_EQ(
       fmt::format(fg(fmt::color::blue) | bg(fmt::color::red), "two color"),
       "\x1b[38;2;000;000;255m\x1b[48;2;255;000;000mtwo color\x1b[0m");
   EXPECT_EQ(fmt::format(fmt::emphasis::bold, "bold"), "\x1b[1mbold\x1b[0m");
+  EXPECT_EQ(fmt::format(fmt::emphasis::faint, "faint"), "\x1b[2mfaint\x1b[0m");
   EXPECT_EQ(fmt::format(fmt::emphasis::italic, "italic"),
             "\x1b[3mitalic\x1b[0m");
   EXPECT_EQ(fmt::format(fmt::emphasis::underline, "underline"),
             "\x1b[4munderline\x1b[0m");
+  EXPECT_EQ(fmt::format(fmt::emphasis::blink, "blink"), "\x1b[5mblink\x1b[0m");
+  EXPECT_EQ(fmt::format(fmt::emphasis::reverse, "reverse"),
+            "\x1b[7mreverse\x1b[0m");
+  EXPECT_EQ(fmt::format(fmt::emphasis::conceal, "conceal"),
+            "\x1b[8mconceal\x1b[0m");
   EXPECT_EQ(fmt::format(fmt::emphasis::strikethrough, "strikethrough"),
             "\x1b[9mstrikethrough\x1b[0m");
   EXPECT_EQ(
@@ -83,4 +50,23 @@ TEST(ColorsTest, Format) {
             "\x1b[105mtbmagenta\x1b[0m");
   EXPECT_EQ(fmt::format(fg(fmt::terminal_color::red), "{}", "foo"),
             "\x1b[31mfoo\x1b[0m");
+  EXPECT_EQ(fmt::format("{}{}", fmt::styled("red", fg(fmt::color::red)),
+                        fmt::styled("bold", fmt::emphasis::bold)),
+            "\x1b[38;2;255;000;000mred\x1b[0m\x1b[1mbold\x1b[0m");
+  EXPECT_EQ(fmt::format("{}", fmt::styled("bar", fg(fmt::color::blue) |
+                                                     fmt::emphasis::underline)),
+            "\x1b[4m\x1b[38;2;000;000;255mbar\x1b[0m");
+}
+
+TEST(color_test, format_to) {
+  auto out = std::string();
+  fmt::format_to(std::back_inserter(out), fg(fmt::rgb(255, 20, 30)),
+                 "rgb(255,20,30){}{}{}", 1, 2, 3);
+  EXPECT_EQ(fmt::to_string(out),
+            "\x1b[38;2;255;020;030mrgb(255,20,30)123\x1b[0m");
+}
+
+TEST(color_test, print) {
+  EXPECT_WRITE(stdout, fmt::print(fg(fmt::rgb(255, 20, 30)), "rgb(255,20,30)"),
+               "\x1b[38;2;255;020;030mrgb(255,20,30)\x1b[0m");
 }

test/compile-error-test/CMakeLists.txt

@@ -1,71 +1,182 @@
 # Test if compile errors are produced where necessary.
 
-cmake_minimum_required(VERSION 3.1.0)
+cmake_minimum_required(VERSION 3.8...3.25)
+project(compile-error-test CXX)
 
-include(CheckCXXSourceCompiles)
-include(CheckCXXCompilerFlag)
+set(fmt_headers "
+  #include <fmt/format.h>
+  #include <fmt/xchar.h>
+  #include <fmt/ostream.h>
+  #include <iostream>
+")
 
-set(CMAKE_REQUIRED_INCLUDES ${CMAKE_CURRENT_SOURCE_DIR}/../../include)
-set(CMAKE_REQUIRED_FLAGS ${CXX_STANDARD_FLAG} ${PEDANTIC_COMPILE_FLAGS})
+set(error_test_names "")
+set(non_error_test_content "")
 
-function (generate_source result fragment)
-  set(${result} "
-  #define FMT_HEADER_ONLY 1
-  #include \"fmt/format.h\"
-  int main() {
-    ${fragment}
-  }
-  " PARENT_SCOPE)
+# For error tests (we expect them to produce compilation error):
+#  * adds a name of test into `error_test_names` list
+#  * generates a single source file (with the same name) for each test
+# For non-error tests (we expect them to compile successfully):
+#  * adds a code segment as separate function to `non_error_test_content`
+function (expect_compile name code_fragment)
+  cmake_parse_arguments(EXPECT_COMPILE "ERROR" "" "" ${ARGN})
+  string(MAKE_C_IDENTIFIER "${name}" test_name)
+
+  if (EXPECT_COMPILE_ERROR)
+    file(WRITE "${CMAKE_CURRENT_BINARY_DIR}/test/${test_name}.cc" "
+      ${fmt_headers}
+      void ${test_name}() {
+        ${code_fragment}
+      }
+    ")
+    set(error_test_names_copy "${error_test_names}")
+    list(APPEND error_test_names_copy "${test_name}")
+    set(error_test_names "${error_test_names_copy}" PARENT_SCOPE)
+  else()
+    set(non_error_test_content "
+      ${non_error_test_content}
+      void ${test_name}() {
+        ${code_fragment}
+      }" PARENT_SCOPE)
+  endif()
 endfunction ()
 
-function (expect_compile code)
-  generate_source(source "${code}")
-  check_cxx_source_compiles("${source}" compiles)
-  if (NOT compiles)
-    set(error_msg "Compile error for: ${code}")
-  endif ()
-  # Unset the CMake cache variable compiles. Otherwise the compile test will
-  # just use cached information next time it runs.
-  unset(compiles CACHE)
-  if (error_msg)
-    message(FATAL_ERROR ${error_msg})
+# Generates a source file for non-error test with `non_error_test_content` and
+# CMake project file with all error and single non-error test targets.
+function (run_tests)
+  set(cmake_targets "")
+  foreach(test_name IN LISTS error_test_names)
+    set(cmake_targets "
+      ${cmake_targets}
+      add_library(test-${test_name} ${test_name}.cc)
+      target_link_libraries(test-${test_name} PRIVATE fmt::fmt)
+    ")
+  endforeach()
+
+  file(WRITE "${CMAKE_CURRENT_BINARY_DIR}/test/non_error_test.cc" "
+    ${fmt_headers}
+    ${non_error_test_content}
+  ")
+  set(cmake_targets "
+    ${cmake_targets}
+    add_library(non-error-test non_error_test.cc)
+    target_link_libraries(non-error-test PRIVATE fmt::fmt)
+  ")
+
+  file(WRITE "${CMAKE_CURRENT_BINARY_DIR}/test/CMakeLists.txt" "
+    cmake_minimum_required(VERSION 3.8...3.25)
+    project(tests CXX)
+    add_subdirectory(${FMT_DIR} fmt)
+    ${cmake_targets}
+  ")
+
+  set(build_directory "${CMAKE_CURRENT_BINARY_DIR}/test/build")
+  file(MAKE_DIRECTORY "${build_directory}")
+  execute_process(
+    COMMAND
+      "${CMAKE_COMMAND}"
+      "-DCMAKE_CXX_COMPILER=${CMAKE_CXX_COMPILER}"
+      "-DCMAKE_CXX_FLAGS=${CMAKE_CXX_FLAGS}"
+      "-DCMAKE_CXX_STANDARD=${CMAKE_CXX_STANDARD}"
+      "-DCMAKE_GENERATOR=${CMAKE_GENERATOR}"
+      "-DCMAKE_MAKE_PROGRAM=${CMAKE_MAKE_PROGRAM}"
+      "-DFMT_DIR=${FMT_DIR}"
+      "${CMAKE_CURRENT_BINARY_DIR}/test"
+    WORKING_DIRECTORY "${build_directory}"
+    RESULT_VARIABLE result_var
+    OUTPUT_VARIABLE output_var
+    ERROR_VARIABLE output_var)
+  if (NOT result_var EQUAL 0)
+    message(FATAL_ERROR "Unable to configure:\n${output_var}")
+  endif()
+
+  foreach(test_name IN LISTS error_test_names)
+    execute_process(
+      COMMAND
+        "${CMAKE_COMMAND}" --build "${build_directory}" --target "test-${test_name}"
+      WORKING_DIRECTORY "${build_directory}"
+      RESULT_VARIABLE result_var
+      OUTPUT_VARIABLE output_var
+      ERROR_QUIET)
+    if (result_var EQUAL 0)
+      message(SEND_ERROR "No compile error for \"${test_name}\":\n${output_var}")
+    endif ()
+  endforeach()
+
+  execute_process(
+    COMMAND
+      "${CMAKE_COMMAND}" --build "${build_directory}" --target "non-error-test"
+    WORKING_DIRECTORY "${build_directory}"
+    RESULT_VARIABLE result_var
+    OUTPUT_VARIABLE output_var
+    ERROR_VARIABLE output_var)
+  if (NOT result_var EQUAL 0)
+    message(SEND_ERROR "Compile error for combined non-error test:\n${output_var}")
   endif ()
 endfunction ()
 
-function (expect_compile_error code)
-  generate_source(source "${code}")
-  check_cxx_source_compiles("${source}" compiles)
-  if (compiles)
-    set(error_msg "No compile error for: ${code}")
-  endif ()
-  # Unset the CMake cache variable compiles. Otherwise the compile test will
-  # just use cached information next time it runs.
-  unset(compiles CACHE)
-  if (error_msg)
-    message(FATAL_ERROR ${error_msg})
-  endif ()
-endfunction ()
 
 # check if the source file skeleton compiles
-expect_compile("")
+expect_compile(check "")
+expect_compile(check-error "compilation_error" ERROR)
 
 # Formatting a wide character with a narrow format string is forbidden.
-expect_compile_error("fmt::format(\"{}\", L'a');")
+expect_compile(wide-character-narrow-format-string "fmt::format(L\"{}\", L'a');")
+expect_compile(wide-character-narrow-format-string-error "fmt::format(\"{}\", L'a');" ERROR)
 
 # Formatting a wide string with a narrow format string is forbidden.
-expect_compile_error("fmt::format(\"{}\", L\"foo\");")
+expect_compile(wide-string-narrow-format-string "fmt::format(L\"{}\", L\"foo\");")
+expect_compile(wide-string-narrow-format-string-error "fmt::format(\"{}\", L\"foo\");" ERROR)
 
 # Formatting a narrow string with a wide format string is forbidden because
 # mixing UTF-8 with UTF-16/32 can result in an invalid output.
-expect_compile_error("fmt::format(L\"{}\", \"foo\");")
+expect_compile(narrow-string-wide-format-string "fmt::format(L\"{}\", L\"foo\");")
+expect_compile(narrow-string-wide-format-string-error "fmt::format(L\"{}\", \"foo\");" ERROR)
 
-# Formatting a wide string with a narrow format string is forbidden.
-expect_compile_error("
+expect_compile(cast-to-string "
+  struct S {
+    operator std::string() const { return std::string(); }
+  };
+  fmt::format(\"{}\", std::string(S()));
+")
+expect_compile(cast-to-string-error "
   struct S {
     operator std::string() const { return std::string(); }
   };
   fmt::format(\"{}\", S());
+" ERROR)
+
+# Formatting a function
+expect_compile(format-function "
+  void (*f)();
+  fmt::format(\"{}\", fmt::ptr(f));
 ")
+expect_compile(format-function-error "
+  void (*f)();
+  fmt::format(\"{}\", f);
+" ERROR)
+
+# Formatting an unformattable argument should always be a compile time error
+expect_compile(format-lots-of-arguments-with-unformattable "
+  struct E {};
+  fmt::format(\"\", 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, E());
+" ERROR)
+expect_compile(format-lots-of-arguments-with-function "
+  void (*f)();
+  fmt::format(\"\", 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, f);
+" ERROR)
+
+# Check if user-defined literals are available
+include(CheckCXXSourceCompiles)
+set(CMAKE_REQUIRED_FLAGS ${CXX_STANDARD_FLAG})
+check_cxx_source_compiles("
+  void operator\"\" _udl(long double);
+  int main() {}"
+  SUPPORTS_USER_DEFINED_LITERALS)
+set(CMAKE_REQUIRED_FLAGS )
+if (NOT SUPPORTS_USER_DEFINED_LITERALS)
+  set (SUPPORTS_USER_DEFINED_LITERALS OFF)
+endif ()
 
 # Make sure that compiler features detected in the header
 # match the features detected in CMake.
@@ -74,6 +185,57 @@ if (SUPPORTS_USER_DEFINED_LITERALS)
 else ()
   set(supports_udl 0)
 endif ()
-expect_compile("#if FMT_USE_USER_DEFINED_LITERALS != ${supports_udl}
-                # error
-                #endif")
+expect_compile(udl-check "
+  #if FMT_USE_USER_DEFINED_LITERALS != ${supports_udl}
+  # error
+  #endif
+")
+
+if (CMAKE_CXX_STANDARD GREATER_EQUAL 20)
+  # Compile-time argument type check
+  expect_compile(format-string-number-spec "
+    #ifdef FMT_HAS_CONSTEVAL
+      fmt::format(\"{:d}\", 42);
+    #endif
+  ")
+  expect_compile(format-string-number-spec-error "
+    #ifdef FMT_HAS_CONSTEVAL
+      fmt::format(\"{:d}\", \"I am not a number\");
+    #else
+      #error
+    #endif
+  " ERROR)
+  expect_compile(print-string-number-spec-error "
+    #ifdef FMT_HAS_CONSTEVAL
+      fmt::print(\"{:d}\", \"I am not a number\");
+    #else
+      #error
+    #endif
+  " ERROR)
+  expect_compile(print-stream-string-number-spec-error "
+  #ifdef FMT_HAS_CONSTEVAL
+    fmt::print(std::cout, \"{:d}\", \"I am not a number\");
+  #else
+    #error
+  #endif
+  " ERROR)
+
+  # Compile-time argument name check
+  expect_compile(format-string-name "
+    #if defined(FMT_HAS_CONSTEVAL) && FMT_USE_NONTYPE_TEMPLATE_ARGS
+      using namespace fmt::literals;
+      fmt::print(\"{foo}\", \"foo\"_a=42);
+    #endif
+  ")
+  expect_compile(format-string-name-error "
+    #if defined(FMT_HAS_CONSTEVAL) && FMT_USE_NONTYPE_TEMPLATE_ARGS
+      using namespace fmt::literals;
+      fmt::print(\"{foo}\", \"bar\"_a=42);
+    #else
+      #error
+    #endif
+  " ERROR)
+endif ()
+
+# Run all tests
+run_tests()

test/compile-fp-test.cc

@@ -0,0 +1,63 @@
+// Formatting library for C++ - formatting library tests
+//
+// Copyright (c) 2012 - present, Victor Zverovich
+// All rights reserved.
+//
+// For the license information refer to format.h.
+
+#include "fmt/compile.h"
+#include "gmock/gmock.h"
+
+#if defined(__cpp_lib_bit_cast) && __cpp_lib_bit_cast >= 201806 && \
+    defined(__cpp_constexpr) && __cpp_constexpr >= 201907 &&       \
+    defined(__cpp_constexpr_dynamic_alloc) &&                      \
+    __cpp_constexpr_dynamic_alloc >= 201907 && FMT_CPLUSPLUS >= 202002L
+
+template <size_t max_string_length, typename Char = char> struct test_string {
+  template <typename T> constexpr bool operator==(const T& rhs) const noexcept {
+    return fmt::basic_string_view<Char>(rhs).compare(buffer) == 0;
+  }
+  Char buffer[max_string_length]{};
+};
+
+template <size_t max_string_length, typename Char = char, typename... Args>
+consteval auto test_format(auto format, const Args&... args) {
+  test_string<max_string_length, Char> string{};
+  fmt::format_to(string.buffer, format, args...);
+  return string;
+}
+
+TEST(compile_time_formatting_test, floating_point) {
+  EXPECT_EQ("0", test_format<2>(FMT_COMPILE("{}"), 0.0f));
+  EXPECT_EQ("392.500000", test_format<11>(FMT_COMPILE("{0:f}"), 392.5f));
+
+  EXPECT_EQ("0", test_format<2>(FMT_COMPILE("{:}"), 0.0));
+  EXPECT_EQ("0.000000", test_format<9>(FMT_COMPILE("{:f}"), 0.0));
+  EXPECT_EQ("0", test_format<2>(FMT_COMPILE("{:g}"), 0.0));
+  EXPECT_EQ("392.65", test_format<7>(FMT_COMPILE("{:}"), 392.65));
+  EXPECT_EQ("392.65", test_format<7>(FMT_COMPILE("{:g}"), 392.65));
+  EXPECT_EQ("392.65", test_format<7>(FMT_COMPILE("{:G}"), 392.65));
+  EXPECT_EQ("4.9014e+06", test_format<11>(FMT_COMPILE("{:g}"), 4.9014e6));
+  EXPECT_EQ("-392.650000", test_format<12>(FMT_COMPILE("{:f}"), -392.65));
+  EXPECT_EQ("-392.650000", test_format<12>(FMT_COMPILE("{:F}"), -392.65));
+
+  EXPECT_EQ("3.926500e+02", test_format<13>(FMT_COMPILE("{0:e}"), 392.65));
+  EXPECT_EQ("3.926500E+02", test_format<13>(FMT_COMPILE("{0:E}"), 392.65));
+  EXPECT_EQ("+0000392.6", test_format<11>(FMT_COMPILE("{0:+010.4g}"), 392.65));
+  EXPECT_EQ("9223372036854775808.000000",
+            test_format<27>(FMT_COMPILE("{:f}"), 9223372036854775807.0));
+
+  constexpr double nan = std::numeric_limits<double>::quiet_NaN();
+  EXPECT_EQ("nan", test_format<4>(FMT_COMPILE("{}"), nan));
+  EXPECT_EQ("+nan", test_format<5>(FMT_COMPILE("{:+}"), nan));
+  if (std::signbit(-nan))
+    EXPECT_EQ("-nan", test_format<5>(FMT_COMPILE("{}"), -nan));
+  else
+    fmt::print("Warning: compiler doesn't handle negative NaN correctly");
+
+  constexpr double inf = std::numeric_limits<double>::infinity();
+  EXPECT_EQ("inf", test_format<4>(FMT_COMPILE("{}"), inf));
+  EXPECT_EQ("+inf", test_format<5>(FMT_COMPILE("{:+}"), inf));
+  EXPECT_EQ("-inf", test_format<5>(FMT_COMPILE("{}"), -inf));
+}
+#endif

test/compile-test.cc

@@ -5,138 +5,68 @@
 //
 // For the license information refer to format.h.
 
-#include <stdint.h>
-
-#include <cctype>
-#include <cfloat>
-#include <climits>
-#include <cmath>
-#include <cstring>
-#include <deque>
-#include <list>
-#include <memory>
-#include <string>
-
-// Check if fmt/compile.h compiles with windows.h included before it.
-#ifdef _WIN32
-#  include <windows.h>
-#endif
-
 #include "fmt/compile.h"
-#include "gmock.h"
+
+#include <type_traits>
+
+#include "fmt/chrono.h"
+#include "gmock/gmock.h"
 #include "gtest-extra.h"
-#include "mock-allocator.h"
-#include "util.h"
 
-#undef ERROR
-#undef min
-#undef max
-
-using testing::Return;
-using testing::StrictMock;
-
-// compiletime_prepared_parts_type_provider is useful only with relaxed
-// constexpr.
-#if FMT_USE_CONSTEXPR
-template <unsigned EXPECTED_PARTS_COUNT, typename Format>
-void check_prepared_parts_type(Format format) {
-  typedef fmt::detail::compiled_format_base<decltype(format)> provider;
-  typedef fmt::detail::format_part<char>
-      expected_parts_type[EXPECTED_PARTS_COUNT];
-  static_assert(std::is_same<typename provider::parts_container,
-                             expected_parts_type>::value,
-                "CompileTimePreparedPartsTypeProvider test failed");
+TEST(iterator_test, counting_iterator) {
+  auto it = fmt::detail::counting_iterator();
+  auto prev = it++;
+  EXPECT_EQ(prev.count(), 0);
+  EXPECT_EQ(it.count(), 1);
+  EXPECT_EQ((it + 41).count(), 42);
 }
 
-TEST(CompileTest, CompileTimePreparedPartsTypeProvider) {
-  check_prepared_parts_type<1u>(FMT_STRING("text"));
-  check_prepared_parts_type<1u>(FMT_STRING("{}"));
-  check_prepared_parts_type<2u>(FMT_STRING("text{}"));
-  check_prepared_parts_type<2u>(FMT_STRING("{}text"));
-  check_prepared_parts_type<3u>(FMT_STRING("text{}text"));
-  check_prepared_parts_type<3u>(FMT_STRING("{:{}.{}} {:{}}"));
-
-  check_prepared_parts_type<3u>(FMT_STRING("{{{}}}"));   // '{', 'argument', '}'
-  check_prepared_parts_type<2u>(FMT_STRING("text{{"));   // 'text', '{'
-  check_prepared_parts_type<3u>(FMT_STRING("text{{ "));  // 'text', '{', ' '
-  check_prepared_parts_type<2u>(FMT_STRING("}}text"));   // '}', text
-  check_prepared_parts_type<2u>(FMT_STRING("text}}text"));  // 'text}', 'text'
-  check_prepared_parts_type<4u>(
-      FMT_STRING("text{{}}text"));  // 'text', '{', '}', 'text'
-}
-#endif
-
-TEST(CompileTest, PassStringLiteralFormat) {
-  const auto prepared = fmt::detail::compile<int>("test {}");
-  EXPECT_EQ("test 42", fmt::format(prepared, 42));
-  const auto wprepared = fmt::detail::compile<int>(L"test {}");
-  EXPECT_EQ(L"test 42", fmt::format(wprepared, 42));
+TEST(compile_test, compile_fallback) {
+  // FMT_COMPILE should fallback on runtime formatting when `if constexpr` is
+  // not available.
+  EXPECT_EQ("42", fmt::format(FMT_COMPILE("{}"), 42));
 }
 
-TEST(CompileTest, FormatToArrayOfChars) {
-  char buffer[32] = {0};
-  const auto prepared = fmt::detail::compile<int>("4{}");
-  fmt::format_to(fmt::detail::make_checked(buffer, 32), prepared, 2);
-  EXPECT_EQ(std::string("42"), buffer);
-  wchar_t wbuffer[32] = {0};
-  const auto wprepared = fmt::detail::compile<int>(L"4{}");
-  fmt::format_to(fmt::detail::make_checked(wbuffer, 32), wprepared, 2);
-  EXPECT_EQ(std::wstring(L"42"), wbuffer);
-}
-
-TEST(CompileTest, FormatToIterator) {
-  std::string s(2, ' ');
-  const auto prepared = fmt::detail::compile<int>("4{}");
-  fmt::format_to(s.begin(), prepared, 2);
-  EXPECT_EQ("42", s);
-  std::wstring ws(2, L' ');
-  const auto wprepared = fmt::detail::compile<int>(L"4{}");
-  fmt::format_to(ws.begin(), wprepared, 2);
-  EXPECT_EQ(L"42", ws);
-}
-
-TEST(CompileTest, FormatToN) {
-  char buf[5];
-  auto f = fmt::detail::compile<int>("{:10}");
-  auto result = fmt::format_to_n(buf, 5, f, 42);
-  EXPECT_EQ(result.size, 10);
-  EXPECT_EQ(result.out, buf + 5);
-  EXPECT_EQ(fmt::string_view(buf, 5), "     ");
-}
-
-TEST(CompileTest, FormattedSize) {
-  auto f = fmt::detail::compile<int>("{:10}");
-  EXPECT_EQ(fmt::formatted_size(f, 42), 10);
-}
-
-TEST(CompileTest, MultipleTypes) {
-  auto f = fmt::detail::compile<int, int>("{} {}");
-  EXPECT_EQ(fmt::format(f, 42, 42), "42 42");
-}
-
-struct formattable {};
+struct type_with_get {
+  template <int> friend void get(type_with_get);
+};
 
 FMT_BEGIN_NAMESPACE
-template <> struct formatter<formattable> : formatter<const char*> {
+template <> struct formatter<type_with_get> : formatter<int> {
   template <typename FormatContext>
-  auto format(formattable, FormatContext& ctx) -> decltype(ctx.out()) {
-    return formatter<const char*>::format("foo", ctx);
+  auto format(type_with_get, FormatContext& ctx) -> decltype(ctx.out()) {
+    return formatter<int>::format(42, ctx);
   }
 };
 FMT_END_NAMESPACE
 
-TEST(CompileTest, FormatUserDefinedType) {
-  auto f = fmt::detail::compile<formattable>("{}");
-  EXPECT_EQ(fmt::format(f, formattable()), "foo");
+TEST(compile_test, compile_type_with_get) {
+  EXPECT_EQ("42", fmt::format(FMT_COMPILE("{}"), type_with_get()));
 }
 
-TEST(CompileTest, EmptyFormatString) {
-  auto f = fmt::detail::compile<>("");
-  EXPECT_EQ(fmt::format(f), "");
-}
+#if defined(__cpp_if_constexpr) && defined(__cpp_return_type_deduction)
+struct test_formattable {};
 
-#ifdef __cpp_if_constexpr
-TEST(CompileTest, FormatDefault) {
+FMT_BEGIN_NAMESPACE
+template <> struct formatter<test_formattable> : formatter<const char*> {
+  char word_spec = 'f';
+  constexpr auto parse(format_parse_context& ctx) {
+    auto it = ctx.begin(), end = ctx.end();
+    if (it == end || *it == '}') return it;
+    if (it != end && (*it == 'f' || *it == 'b')) word_spec = *it++;
+    if (it != end && *it != '}') throw format_error("invalid format");
+    return it;
+  }
+  template <typename FormatContext>
+  constexpr auto format(test_formattable, FormatContext& ctx) const
+      -> decltype(ctx.out()) {
+    return formatter<const char*>::format(word_spec == 'f' ? "foo" : "bar",
+                                          ctx);
+  }
+};
+FMT_END_NAMESPACE
+
+TEST(compile_test, format_default) {
   EXPECT_EQ("42", fmt::format(FMT_COMPILE("{}"), 42));
   EXPECT_EQ("42", fmt::format(FMT_COMPILE("{}"), 42u));
   EXPECT_EQ("42", fmt::format(FMT_COMPILE("{}"), 42ll));
@@ -146,21 +76,299 @@ TEST(CompileTest, FormatDefault) {
   EXPECT_EQ("4.2", fmt::format(FMT_COMPILE("{}"), 4.2));
   EXPECT_EQ("foo", fmt::format(FMT_COMPILE("{}"), "foo"));
   EXPECT_EQ("foo", fmt::format(FMT_COMPILE("{}"), std::string("foo")));
-  EXPECT_EQ("foo", fmt::format(FMT_COMPILE("{}"), formattable()));
+  EXPECT_EQ("foo", fmt::format(FMT_COMPILE("{}"), test_formattable()));
+  auto t = std::chrono::system_clock::now();
+  EXPECT_EQ(fmt::format("{}", t), fmt::format(FMT_COMPILE("{}"), t));
+#  ifdef __cpp_lib_byte
+  EXPECT_EQ("42", fmt::format(FMT_COMPILE("{}"), std::byte{42}));
+#  endif
 }
 
-TEST(CompileTest, FormatSpecs) {
+TEST(compile_test, format_wide_string) {
+  EXPECT_EQ(L"42", fmt::format(FMT_COMPILE(L"{}"), 42));
+}
+
+TEST(compile_test, format_specs) {
   EXPECT_EQ("42", fmt::format(FMT_COMPILE("{:x}"), 0x42));
+  EXPECT_EQ("1.2 ms ",
+            fmt::format(FMT_COMPILE("{:7.1%Q %q}"),
+                        std::chrono::duration<double, std::milli>(1.234)));
 }
 
-TEST(CompileTest, FormatTo) {
+TEST(compile_test, dynamic_format_specs) {
+  EXPECT_EQ("foo  ", fmt::format(FMT_COMPILE("{:{}}"), "foo", 5));
+  EXPECT_EQ("  3.14", fmt::format(FMT_COMPILE("{:{}.{}f}"), 3.141592, 6, 2));
+  EXPECT_EQ(
+      "=1.234ms=",
+      fmt::format(FMT_COMPILE("{:=^{}.{}}"),
+                  std::chrono::duration<double, std::milli>(1.234), 9, 3));
+}
+
+TEST(compile_test, manual_ordering) {
+  EXPECT_EQ("42", fmt::format(FMT_COMPILE("{0}"), 42));
+  EXPECT_EQ(" -42", fmt::format(FMT_COMPILE("{0:4}"), -42));
+  EXPECT_EQ("41 43", fmt::format(FMT_COMPILE("{0} {1}"), 41, 43));
+  EXPECT_EQ("41 43", fmt::format(FMT_COMPILE("{1} {0}"), 43, 41));
+  EXPECT_EQ("41 43", fmt::format(FMT_COMPILE("{0} {2}"), 41, 42, 43));
+  EXPECT_EQ("  41   43", fmt::format(FMT_COMPILE("{1:{2}} {0:4}"), 43, 41, 4));
+  EXPECT_EQ("42 1.2 ms ",
+            fmt::format(FMT_COMPILE("{0} {1:7.1%Q %q}"), 42,
+                        std::chrono::duration<double, std::milli>(1.234)));
+  EXPECT_EQ(
+      "true 42 42 foo 0x1234 foo",
+      fmt::format(FMT_COMPILE("{0} {1} {2} {3} {4} {5}"), true, 42, 42.0f,
+                  "foo", reinterpret_cast<void*>(0x1234), test_formattable()));
+  EXPECT_EQ(L"42", fmt::format(FMT_COMPILE(L"{0}"), 42));
+}
+
+TEST(compile_test, named) {
+  auto runtime_named_field_compiled =
+      fmt::detail::compile<decltype(fmt::arg("arg", 42))>(FMT_COMPILE("{arg}"));
+  static_assert(std::is_same_v<decltype(runtime_named_field_compiled),
+                               fmt::detail::runtime_named_field<char>>);
+
+  EXPECT_EQ("42", fmt::format(FMT_COMPILE("{}"), fmt::arg("arg", 42)));
+  EXPECT_EQ("41 43", fmt::format(FMT_COMPILE("{} {}"), fmt::arg("arg", 41),
+                                 fmt::arg("arg", 43)));
+
+  EXPECT_EQ("foobar",
+            fmt::format(FMT_COMPILE("{a0}{a1}"), fmt::arg("a0", "foo"),
+                        fmt::arg("a1", "bar")));
+  EXPECT_EQ("foobar", fmt::format(FMT_COMPILE("{}{a1}"), fmt::arg("a0", "foo"),
+                                  fmt::arg("a1", "bar")));
+  EXPECT_EQ("foofoo", fmt::format(FMT_COMPILE("{a0}{}"), fmt::arg("a0", "foo"),
+                                  fmt::arg("a1", "bar")));
+  EXPECT_EQ("foobar", fmt::format(FMT_COMPILE("{0}{a1}"), fmt::arg("a0", "foo"),
+                                  fmt::arg("a1", "bar")));
+  EXPECT_EQ("foobar", fmt::format(FMT_COMPILE("{a0}{1}"), fmt::arg("a0", "foo"),
+                                  fmt::arg("a1", "bar")));
+
+  EXPECT_EQ("foobar",
+            fmt::format(FMT_COMPILE("{}{a1}"), "foo", fmt::arg("a1", "bar")));
+  EXPECT_EQ("foobar",
+            fmt::format(FMT_COMPILE("{a0}{a1}"), fmt::arg("a1", "bar"),
+                        fmt::arg("a2", "baz"), fmt::arg("a0", "foo")));
+  EXPECT_EQ(" bar foo ",
+            fmt::format(FMT_COMPILE(" {foo} {bar} "), fmt::arg("foo", "bar"),
+                        fmt::arg("bar", "foo")));
+
+  EXPECT_THROW(fmt::format(FMT_COMPILE("{invalid}"), fmt::arg("valid", 42)),
+               fmt::format_error);
+
+#  if FMT_USE_NONTYPE_TEMPLATE_ARGS
+  using namespace fmt::literals;
+  auto statically_named_field_compiled =
+      fmt::detail::compile<decltype("arg"_a = 42)>(FMT_COMPILE("{arg}"));
+  static_assert(std::is_same_v<decltype(statically_named_field_compiled),
+                               fmt::detail::field<char, int, 0>>);
+
+  EXPECT_EQ("41 43",
+            fmt::format(FMT_COMPILE("{a0} {a1}"), "a0"_a = 41, "a1"_a = 43));
+  EXPECT_EQ("41 43",
+            fmt::format(FMT_COMPILE("{a1} {a0}"), "a0"_a = 43, "a1"_a = 41));
+#  endif
+}
+
+TEST(compile_test, join) {
+  unsigned char data[] = {0x1, 0x2, 0xaf};
+  EXPECT_EQ("0102af", fmt::format(FMT_COMPILE("{:02x}"), fmt::join(data, "")));
+}
+
+TEST(compile_test, format_to) {
   char buf[8];
   auto end = fmt::format_to(buf, FMT_COMPILE("{}"), 42);
   *end = '\0';
   EXPECT_STREQ("42", buf);
+  end = fmt::format_to(buf, FMT_COMPILE("{:x}"), 42);
+  *end = '\0';
+  EXPECT_STREQ("2a", buf);
 }
 
-TEST(CompileTest, TextAndArg) {
+TEST(compile_test, format_to_n) {
+  constexpr auto buffer_size = 8;
+  char buffer[buffer_size];
+  auto res = fmt::format_to_n(buffer, buffer_size, FMT_COMPILE("{}"), 42);
+  *res.out = '\0';
+  EXPECT_STREQ("42", buffer);
+  res = fmt::format_to_n(buffer, buffer_size, FMT_COMPILE("{:x}"), 42);
+  *res.out = '\0';
+  EXPECT_STREQ("2a", buffer);
+}
+
+#  ifdef __cpp_lib_bit_cast
+TEST(compile_test, constexpr_formatted_size) {
+  FMT_CONSTEXPR20 size_t size = fmt::formatted_size(FMT_COMPILE("{}"), 42);
+  EXPECT_EQ(size, 2);
+  FMT_CONSTEXPR20 size_t hex_size =
+      fmt::formatted_size(FMT_COMPILE("{:x}"), 15);
+  EXPECT_EQ(hex_size, 1);
+  FMT_CONSTEXPR20 size_t binary_size =
+      fmt::formatted_size(FMT_COMPILE("{:b}"), 15);
+  EXPECT_EQ(binary_size, 4);
+  FMT_CONSTEXPR20 size_t padded_size =
+      fmt::formatted_size(FMT_COMPILE("{:*^6}"), 42);
+  EXPECT_EQ(padded_size, 6);
+  FMT_CONSTEXPR20 size_t float_size =
+      fmt::formatted_size(FMT_COMPILE("{:.3}"), 12.345);
+  EXPECT_EQ(float_size, 4);
+  FMT_CONSTEXPR20 size_t str_size =
+      fmt::formatted_size(FMT_COMPILE("{:s}"), "abc");
+  EXPECT_EQ(str_size, 3);
+}
+#  endif
+
+TEST(compile_test, text_and_arg) {
   EXPECT_EQ(">>>42<<<", fmt::format(FMT_COMPILE(">>>{}<<<"), 42));
+  EXPECT_EQ("42!", fmt::format(FMT_COMPILE("{}!"), 42));
+}
+
+TEST(compile_test, unknown_format_fallback) {
+  EXPECT_EQ(" 42 ",
+            fmt::format(FMT_COMPILE("{name:^4}"), fmt::arg("name", 42)));
+
+  std::vector<char> v;
+  fmt::format_to(std::back_inserter(v), FMT_COMPILE("{name:^4}"),
+                 fmt::arg("name", 42));
+  EXPECT_EQ(" 42 ", fmt::string_view(v.data(), v.size()));
+
+  char buffer[4];
+  auto result = fmt::format_to_n(buffer, 4, FMT_COMPILE("{name:^5}"),
+                                 fmt::arg("name", 42));
+  EXPECT_EQ(5u, result.size);
+  EXPECT_EQ(buffer + 4, result.out);
+  EXPECT_EQ(" 42 ", fmt::string_view(buffer, 4));
+}
+
+TEST(compile_test, empty) { EXPECT_EQ("", fmt::format(FMT_COMPILE(""))); }
+
+struct to_stringable {
+  friend fmt::string_view to_string_view(to_stringable) { return {}; }
+};
+
+FMT_BEGIN_NAMESPACE
+template <> struct formatter<to_stringable> {
+  auto parse(format_parse_context& ctx) const -> decltype(ctx.begin()) {
+    return ctx.begin();
+  }
+
+  template <typename FormatContext>
+  auto format(const to_stringable&, FormatContext& ctx) -> decltype(ctx.out()) {
+    return ctx.out();
+  }
+};
+FMT_END_NAMESPACE
+
+TEST(compile_test, to_string_and_formatter) {
+  fmt::format(FMT_COMPILE("{}"), to_stringable());
+}
+
+TEST(compile_test, print) {
+  EXPECT_WRITE(stdout, fmt::print(FMT_COMPILE("Don't {}!"), "panic"),
+               "Don't panic!");
+  EXPECT_WRITE(stderr, fmt::print(stderr, FMT_COMPILE("Don't {}!"), "panic"),
+               "Don't panic!");
+}
+#endif
+
+#if FMT_USE_NONTYPE_TEMPLATE_ARGS
+TEST(compile_test, compile_format_string_literal) {
+  using namespace fmt::literals;
+  EXPECT_EQ("", fmt::format(""_cf));
+  EXPECT_EQ("42", fmt::format("{}"_cf, 42));
+  EXPECT_EQ(L"42", fmt::format(L"{}"_cf, 42));
+}
+#endif
+
+// MSVS 2019 19.29.30145.0 - Support C++20 and OK.
+// MSVS 2022 19.32.31332.0 - compile-test.cc(362,3): fatal error C1001: Internal
+// compiler error.
+//  (compiler file
+//  'D:\a\_work\1\s\src\vctools\Compiler\CxxFE\sl\p1\c\constexpr\constexpr.cpp',
+//  line 8635)
+#if ((FMT_CPLUSPLUS >= 202002L) &&                           \
+     (!defined(_GLIBCXX_RELEASE) || _GLIBCXX_RELEASE > 9) && \
+     (!FMT_MSC_VERSION || FMT_MSC_VERSION < 1930)) ||        \
+    (FMT_CPLUSPLUS >= 201709L && FMT_GCC_VERSION >= 1002)
+template <size_t max_string_length, typename Char = char> struct test_string {
+  template <typename T> constexpr bool operator==(const T& rhs) const noexcept {
+    return fmt::basic_string_view<Char>(rhs).compare(buffer) == 0;
+  }
+  Char buffer[max_string_length]{};
+};
+
+template <size_t max_string_length, typename Char = char, typename... Args>
+consteval auto test_format(auto format, const Args&... args) {
+  test_string<max_string_length, Char> string{};
+  fmt::format_to(string.buffer, format, args...);
+  return string;
+}
+
+TEST(compile_time_formatting_test, bool) {
+  EXPECT_EQ("true", test_format<5>(FMT_COMPILE("{}"), true));
+  EXPECT_EQ("false", test_format<6>(FMT_COMPILE("{}"), false));
+  EXPECT_EQ("true ", test_format<6>(FMT_COMPILE("{:5}"), true));
+  EXPECT_EQ("1", test_format<2>(FMT_COMPILE("{:d}"), true));
+}
+
+TEST(compile_time_formatting_test, integer) {
+  EXPECT_EQ("42", test_format<3>(FMT_COMPILE("{}"), 42));
+  EXPECT_EQ("420", test_format<4>(FMT_COMPILE("{}"), 420));
+  EXPECT_EQ("42 42", test_format<6>(FMT_COMPILE("{} {}"), 42, 42));
+  EXPECT_EQ("42 42",
+            test_format<6>(FMT_COMPILE("{} {}"), uint32_t{42}, uint64_t{42}));
+
+  EXPECT_EQ("+42", test_format<4>(FMT_COMPILE("{:+}"), 42));
+  EXPECT_EQ("42", test_format<3>(FMT_COMPILE("{:-}"), 42));
+  EXPECT_EQ(" 42", test_format<4>(FMT_COMPILE("{: }"), 42));
+
+  EXPECT_EQ("-0042", test_format<6>(FMT_COMPILE("{:05}"), -42));
+
+  EXPECT_EQ("101010", test_format<7>(FMT_COMPILE("{:b}"), 42));
+  EXPECT_EQ("0b101010", test_format<9>(FMT_COMPILE("{:#b}"), 42));
+  EXPECT_EQ("0B101010", test_format<9>(FMT_COMPILE("{:#B}"), 42));
+  EXPECT_EQ("042", test_format<4>(FMT_COMPILE("{:#o}"), 042));
+  EXPECT_EQ("0x4a", test_format<5>(FMT_COMPILE("{:#x}"), 0x4a));
+  EXPECT_EQ("0X4A", test_format<5>(FMT_COMPILE("{:#X}"), 0x4a));
+
+  EXPECT_EQ("   42", test_format<6>(FMT_COMPILE("{:5}"), 42));
+  EXPECT_EQ("   42", test_format<6>(FMT_COMPILE("{:5}"), 42ll));
+  EXPECT_EQ("   42", test_format<6>(FMT_COMPILE("{:5}"), 42ull));
+
+  EXPECT_EQ("42  ", test_format<5>(FMT_COMPILE("{:<4}"), 42));
+  EXPECT_EQ("  42", test_format<5>(FMT_COMPILE("{:>4}"), 42));
+  EXPECT_EQ(" 42 ", test_format<5>(FMT_COMPILE("{:^4}"), 42));
+  EXPECT_EQ("**-42", test_format<6>(FMT_COMPILE("{:*>5}"), -42));
+}
+
+TEST(compile_time_formatting_test, char) {
+  EXPECT_EQ("c", test_format<2>(FMT_COMPILE("{}"), 'c'));
+
+  EXPECT_EQ("c  ", test_format<4>(FMT_COMPILE("{:3}"), 'c'));
+  EXPECT_EQ("99", test_format<3>(FMT_COMPILE("{:d}"), 'c'));
+}
+
+TEST(compile_time_formatting_test, string) {
+  EXPECT_EQ("42", test_format<3>(FMT_COMPILE("{}"), "42"));
+  EXPECT_EQ("The answer is 42",
+            test_format<17>(FMT_COMPILE("{} is {}"), "The answer", "42"));
+
+  EXPECT_EQ("abc**", test_format<6>(FMT_COMPILE("{:*<5}"), "abc"));
+  EXPECT_EQ("**🤡**", test_format<9>(FMT_COMPILE("{:*^6}"), "🤡"));
+}
+
+TEST(compile_time_formatting_test, combination) {
+  EXPECT_EQ("420, true, answer",
+            test_format<18>(FMT_COMPILE("{}, {}, {}"), 420, true, "answer"));
+
+  EXPECT_EQ(" -42", test_format<5>(FMT_COMPILE("{:{}}"), -42, 4));
+}
+
+TEST(compile_time_formatting_test, custom_type) {
+  EXPECT_EQ("foo", test_format<4>(FMT_COMPILE("{}"), test_formattable()));
+  EXPECT_EQ("bar", test_format<4>(FMT_COMPILE("{:b}"), test_formattable()));
+}
+
+TEST(compile_time_formatting_test, multibyte_fill) {
+  EXPECT_EQ("жж42", test_format<8>(FMT_COMPILE("{:ж>4}"), 42));
 }
 #endif

test/custom-formatter-test.cc

@@ -1,58 +0,0 @@
-// Formatting library for C++ - custom argument formatter tests
-//
-// Copyright (c) 2012 - present, Victor Zverovich
-// All rights reserved.
-//
-// For the license information refer to format.h.
-
-#ifndef _CRT_SECURE_NO_WARNINGS
-#define _CRT_SECURE_NO_WARNINGS
-#endif
-
-#include "fmt/format.h"
-#include "gtest-extra.h"
-
-// MSVC 2013 is known to be broken.
-#if !FMT_MSC_VER || FMT_MSC_VER > 1800
-
-// A custom argument formatter that doesn't print `-` for floating-point values
-// rounded to 0.
-class custom_arg_formatter
-    : public fmt::detail::arg_formatter<fmt::format_context::iterator, char> {
- public:
-  using base = fmt::detail::arg_formatter<fmt::format_context::iterator, char>;
-
-  custom_arg_formatter(fmt::format_context& ctx,
-                       fmt::format_parse_context* parse_ctx,
-                       fmt::format_specs* s = nullptr,
-                       const char* = nullptr)
-      : base(ctx, parse_ctx, s) {}
-
-  using base::operator();
-
-  iterator operator()(double value) {
-    // Comparing a float to 0.0 is safe.
-    if (round(value * pow(10, specs()->precision)) == 0.0) value = 0;
-    return base::operator()(value);
-  }
-};
-
-std::string custom_vformat(fmt::string_view format_str, fmt::format_args args) {
-  fmt::memory_buffer buffer;
-  fmt::detail::buffer<char>& base = buffer;
-  // Pass custom argument formatter as a template arg to vwrite.
-  fmt::vformat_to<custom_arg_formatter>(std::back_inserter(base), format_str,
-                                        args);
-  return std::string(buffer.data(), buffer.size());
-}
-
-template <typename... Args>
-std::string custom_format(const char* format_str, const Args&... args) {
-  auto va = fmt::make_format_args(args...);
-  return custom_vformat(format_str, va);
-}
-
-TEST(CustomFormatterTest, Format) {
-  EXPECT_EQ("0.00", custom_format("{:.2f}", -.00001));
-}
-#endif

test/detect-stdfs.cc

@@ -0,0 +1,18 @@
+// Formatting library for C++ - tests of formatters for standard library types
+//
+// Copyright (c) 2012 - present, Victor Zverovich
+// All rights reserved.
+//
+// For the license information refer to format.h.
+
+#include <exception>  // _GLIBCXX_RELEASE & _LIBCPP_VERSION
+
+#if defined(_GLIBCXX_RELEASE) && _GLIBCXX_RELEASE == 8
+#  error libfound "stdc++fs"
+#elif !defined(__apple_build_version__) && defined(_LIBCPP_VERSION) && \
+    _LIBCPP_VERSION >= 7000 && _LIBCPP_VERSION < 9000
+#  error libfound "c++fs"
+#else
+// none if std::filesystem does not require additional libraries
+#  error libfound ""
+#endif

test/enforce-checks-test.cc

@@ -0,0 +1,65 @@
+// Formatting library for C++ - formatting library tests
+//
+// Copyright (c) 2012 - present, Victor Zverovich
+// All rights reserved.
+//
+// For the license information refer to format.h.
+
+#include <iterator>
+#include <vector>
+
+#define I 42  // simulate https://en.cppreference.com/w/c/numeric/complex/I
+#include "fmt/chrono.h"
+#include "fmt/color.h"
+#include "fmt/format.h"
+#include "fmt/ostream.h"
+#include "fmt/ranges.h"
+#include "fmt/xchar.h"
+#undef I
+
+// Exercise the API to verify that everything we expect to can compile.
+void test_format_api() {
+  (void)fmt::format(FMT_STRING("{}"), 42);
+  (void)fmt::format(FMT_STRING(L"{}"), 42);
+  (void)fmt::format(FMT_STRING("noop"));
+
+  (void)fmt::to_string(42);
+  (void)fmt::to_wstring(42);
+
+  std::vector<char> out;
+  fmt::format_to(std::back_inserter(out), FMT_STRING("{}"), 42);
+
+  char buffer[4];
+  fmt::format_to_n(buffer, 3, FMT_STRING("{}"), 12345);
+
+  wchar_t wbuffer[4];
+  fmt::format_to_n(wbuffer, 3, FMT_STRING(L"{}"), 12345);
+}
+
+void test_chrono() {
+  (void)fmt::format(FMT_STRING("{}"), std::chrono::seconds(42));
+  (void)fmt::format(FMT_STRING(L"{}"), std::chrono::seconds(42));
+}
+
+void test_text_style() {
+  fmt::print(fg(fmt::rgb(255, 20, 30)), FMT_STRING("{}"), "rgb(255,20,30)");
+  (void)fmt::format(fg(fmt::rgb(255, 20, 30)), FMT_STRING("{}"),
+                    "rgb(255,20,30)");
+
+  fmt::text_style ts = fg(fmt::rgb(255, 20, 30));
+  std::string out;
+  fmt::format_to(std::back_inserter(out), ts,
+                 FMT_STRING("rgb(255,20,30){}{}{}"), 1, 2, 3);
+}
+
+void test_range() {
+  std::vector<char> hello = {'h', 'e', 'l', 'l', 'o'};
+  (void)fmt::format(FMT_STRING("{}"), hello);
+}
+
+int main() {
+  test_format_api();
+  test_chrono();
+  test_text_style();
+  test_range();
+}

test/find-package-test/CMakeLists.txt

@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.1.0)
+cmake_minimum_required(VERSION 3.8...3.25)
 
 project(fmt-test)
 

test/find-package-test/main.cc

@@ -1,6 +1,5 @@
 #include "fmt/format.h"
 
 int main(int argc, char** argv) {
-  for(int i = 0; i < argc; ++i)
-    fmt::print("{}: {}\n", i, argv[i]);
+  for (int i = 0; i < argc; ++i) fmt::print("{}: {}\n", i, argv[i]);
 }

test/format

@@ -1,855 +0,0 @@
-// Formatting library for C++ - the standard API implementation
-//
-// Copyright (c) 2012 - present, Victor Zverovich
-// All rights reserved.
-//
-// For the license information refer to format.h.
-
-#ifndef FMT_FORMAT_
-#define FMT_FORMAT_
-
-#include <cassert>
-#include <variant>
-#include "fmt/format.h"
-
-// This implementation verifies the correctness of the standard API proposed in
-// P0645 Text Formatting and is optimized for copy-pasting from the paper, not
-// for efficiency or readability. An efficient implementation should not use
-// std::variant and should store packed argument type tags separately from
-// values in basic_format_args for small number of arguments.
-
-namespace std {
-template<class T>
-constexpr bool Integral = is_integral_v<T>;
-
-template <class O>
-  using iter_difference_t = ptrdiff_t;
-}
-
-// https://fmt.dev/Text%20Formatting.html#format.syn
-namespace std {
-  // [format.error], class format_error
-  class format_error;
-
-  // [format.formatter], formatter
-  template<class charT> class basic_format_parse_context;
-  using format_parse_context = basic_format_parse_context<char>;
-  using wformat_parse_context = basic_format_parse_context<wchar_t>;
-  
-  template<class Out, class charT> class basic_format_context;
-  using format_context = basic_format_context<
-    /* unspecified */ std::back_insert_iterator<fmt::detail::buffer<char>>, char>;
-  using wformat_context = basic_format_context<
-    /* unspecified */ std::back_insert_iterator<fmt::detail::buffer<wchar_t>>, wchar_t>;
-
-  template<class T, class charT = char> struct formatter {
-    formatter() = delete;
-  };
-  
-  // [format.arguments], arguments
-  template<class Context> class basic_format_arg;
-
-  template<class Visitor, class Context>
-    /* see below */ auto visit_format_arg(Visitor&& vis, basic_format_arg<Context> arg);
-
-  template<class Context, class... Args> struct format_arg_store; // exposition only
-
-  template<class Context> class basic_format_args;
-  using format_args = basic_format_args<format_context>;
-  using wformat_args = basic_format_args<wformat_context>;
-
-  template<class Out, class charT>
-    using format_args_t = basic_format_args<basic_format_context<Out, charT>>;
-
-  template<class Context = format_context, class... Args>
-    format_arg_store<Context, Args...>
-      make_format_args(const Args&... args);
-  template<class... Args>
-    format_arg_store<wformat_context, Args...>
-      make_wformat_args(const Args&... args);
-
-  // [format.functions], formatting functions
-  template<class... Args>
-    string format(string_view fmt, const Args&... args);
-  template<class... Args>
-    wstring format(wstring_view fmt, const Args&... args);
-
-  string vformat(string_view fmt, format_args args);
-  wstring vformat(wstring_view fmt, wformat_args args);
-
-  template<class Out, class... Args>
-    Out format_to(Out out, string_view fmt, const Args&... args);
-  template<class Out, class... Args>
-    Out format_to(Out out, wstring_view fmt, const Args&... args);
-
-  template<class Out>
-    Out vformat_to(Out out, string_view fmt, format_args_t<fmt::type_identity_t<Out>, char> args);
-  template<class Out>
-    Out vformat_to(Out out, wstring_view fmt, format_args_t<fmt::type_identity_t<Out>, wchar_t> args);
-
-  template<class Out>
-    struct format_to_n_result {
-      Out out;
-      iter_difference_t<Out> size;
-    };
-  
-  template<class Out, class... Args>
-    format_to_n_result<Out> format_to_n(Out out, iter_difference_t<Out> n,
-                                        string_view fmt, const Args&... args);
-  template<class Out, class... Args>
-    format_to_n_result<Out> format_to_n(Out out, iter_difference_t<Out> n,
-                                        wstring_view fmt, const Args&... args);
-
-  template<class... Args>
-    size_t formatted_size(string_view fmt, const Args&... args);
-  template<class... Args>
-    size_t formatted_size(wstring_view fmt, const Args&... args);
-}
-
-// https://fmt.dev/Text%20Formatting.html#format.error
-namespace std {
-  class format_error : public runtime_error {
-  public:
-    explicit format_error(const string& what_arg) : runtime_error(what_arg) {}
-    explicit format_error(const char* what_arg) : runtime_error(what_arg) {}
-  };
-}
-
-namespace std {
-namespace detail {
-struct error_handler {
-  // This function is intentionally not constexpr to give a compile-time error.
-  void on_error(const char* message) {
-    throw std::format_error(message);
-  }
-};
-}
-}
-
-// https://fmt.dev/Text%20Formatting.html#format.parse_context
-namespace std {
-  template<class charT>
-  class basic_format_parse_context {
-  public:
-    using char_type = charT;
-    using const_iterator = typename basic_string_view<charT>::const_iterator;
-    using iterator = const_iterator;
-
-  private:
-    iterator begin_;                              // exposition only
-    iterator end_;                                // exposition only
-    enum indexing { unknown, manual, automatic }; // exposition only
-    indexing indexing_;                           // exposition only
-    size_t next_arg_id_;                          // exposition only
-    size_t num_args_;                             // exposition only
-
-  public:
-    explicit constexpr basic_format_parse_context(basic_string_view<charT> fmt,
-                                                  size_t num_args = 0) noexcept;
-    basic_format_parse_context(const basic_format_parse_context&) = delete;
-    basic_format_parse_context& operator=(const basic_format_parse_context&) = delete;
-
-    constexpr const_iterator begin() const noexcept;
-    constexpr const_iterator end() const noexcept;
-    constexpr void advance_to(const_iterator it);
-
-    constexpr size_t next_arg_id();
-    constexpr void check_arg_id(size_t id);
-
-    // Implementation detail:
-    constexpr void check_arg_id(fmt::string_view) {}
-    detail::error_handler error_handler() const { return {}; }
-    void on_error(const char* msg) { error_handler().on_error(msg); }
-  };
-}
-
-namespace std {
-template<class charT>
-/* explicit */ constexpr basic_format_parse_context<charT>::
-                   basic_format_parse_context(basic_string_view<charT> fmt,
-                                              size_t num_args) noexcept
-: begin_(fmt.begin()), end_(fmt.end()), indexing_(unknown), next_arg_id_(0), num_args_(num_args) {}
-
-template<class charT>
-constexpr typename basic_format_parse_context<charT>::const_iterator basic_format_parse_context<charT>::begin() const noexcept { return begin_; }
-
-template<class charT>
-constexpr typename basic_format_parse_context<charT>::const_iterator basic_format_parse_context<charT>::end() const noexcept { return end_; }
-
-template<class charT>
-constexpr void basic_format_parse_context<charT>::advance_to(typename basic_format_parse_context<charT>::iterator it) { begin_ = it; }
-
-template<class charT>
-constexpr size_t basic_format_parse_context<charT>::next_arg_id() {
-  if (indexing_ == manual)
-    throw format_error("manual to automatic indexing");
-  if (indexing_ == unknown)
-    indexing_ = automatic;
-  return next_arg_id_++;
-}
-
-template<class charT>
-constexpr void basic_format_parse_context<charT>::check_arg_id(size_t id) {
-  // clang doesn't support __builtin_is_constant_evaluated yet
-  //if (!(!__builtin_is_constant_evaluated() || id < num_args_))
-  //  throw format_error(invalid index is out of range");
-  if (indexing_ == automatic)
-    throw format_error("automatic to manual indexing");
-  if (indexing_ == unknown)
-    indexing_ = manual;
-}
-}
-
-// https://fmt.dev/Text%20Formatting.html#format.context
-namespace std {
-  template<class Out, class charT>
-  class basic_format_context {
-    basic_format_args<basic_format_context> args_; // exposition only
-    Out out_;                                      // exposition only
-
-  public:
-    using iterator = Out;
-    using char_type = charT;
-    template<class T> using formatter_type = formatter<T, charT>;
-
-    basic_format_arg<basic_format_context> arg(size_t id) const;
-
-    iterator out();
-    void advance_to(iterator it);
-
-    // Implementation details:
-    using format_arg = basic_format_arg<basic_format_context>;
-    basic_format_context(Out out, basic_format_args<basic_format_context> args, fmt::detail::locale_ref)
-    : args_(args), out_(out) {}
-    detail::error_handler error_handler() const { return {}; }
-    basic_format_arg<basic_format_context> arg(fmt::basic_string_view<charT>) const {
-      return {}; // unused: named arguments are not supported yet
-    }
-    void on_error(const char* msg) { error_handler().on_error(msg); }
-  };
-}
-
-namespace std {
-template<class O, class charT>
-basic_format_arg<basic_format_context<O, charT>> basic_format_context<O, charT>::arg(size_t id) const { return args_.get(id); }
-
-template<class O, class charT>
-typename basic_format_context<O, charT>::iterator basic_format_context<O, charT>::out() { return out_; }
-
-template<class O, class charT>
-void basic_format_context<O, charT>::advance_to(typename basic_format_context<O, charT>::iterator it) { out_ = it; }
-}
-
-namespace std {
-namespace detail {
-template <typename T>
-constexpr bool is_standard_integer_v =
-    std::is_same_v<T, signed char> ||
-    std::is_same_v<T, short int> ||
-    std::is_same_v<T, int> ||
-    std::is_same_v<T, long int> ||
-    std::is_same_v<T, long long int>;
-
-template <typename T>
-constexpr bool is_standard_unsigned_integer_v =
-    std::is_same_v<T, unsigned char> ||
-    std::is_same_v<T, unsigned short int> ||
-    std::is_same_v<T, unsigned int> ||
-    std::is_same_v<T, unsigned long int> ||
-    std::is_same_v<T, unsigned long long int>;
-
-template <typename T, typename Char> struct formatter;
-}
-}
-
-// https://fmt.dev/Text%20Formatting.html#format.arg
-namespace std {
-  template<class Context>
-  class basic_format_arg {
-  public:
-    class handle;
-
-  private:
-    using char_type = typename Context::char_type;                       // exposition only
-
-    variant<monostate, bool, char_type,
-            int, unsigned int, long long int, unsigned long long int,
-            double, long double,
-            const char_type*, basic_string_view<char_type>,
-            const void*, handle> value;                                  // exposition only
-
-    template<typename T,
-      typename = enable_if_t<
-        std::is_same_v<T, bool> ||
-        std::is_same_v<T, char_type> ||
-        (std::is_same_v<T, char> && std::is_same_v<char_type, wchar_t>) ||
-        detail::is_standard_integer_v<T> ||
-        detail::is_standard_unsigned_integer_v<T> ||
-        sizeof(typename Context::template formatter_type<T>().format(declval<const T&>(), declval<Context&>())) != 0
-    >> explicit basic_format_arg(const T& v) noexcept; // exposition only
-    explicit basic_format_arg(float n) noexcept;                         // exposition only
-    explicit basic_format_arg(double n) noexcept;                        // exposition only
-    explicit basic_format_arg(long double n) noexcept;                   // exposition only
-    explicit basic_format_arg(const char_type* s);                       // exposition only
-
-    template<class traits>
-      explicit basic_format_arg(
-        basic_string_view<char_type, traits> s) noexcept;                // exposition only
-
-    template<class traits, class Allocator>
-      explicit basic_format_arg(
-        const basic_string<char_type, traits, Allocator>& s) noexcept;   // exposition only
-
-    explicit basic_format_arg(nullptr_t) noexcept;                       // exposition only
-
-    template<class T, typename = enable_if_t<is_void_v<T>>>
-      explicit basic_format_arg(const T* p) noexcept;                    // exposition only
-
-    // Fails due to a bug in clang
-    //template<class Visitor, class Ctx>
-    //  friend auto visit_format_arg(Visitor&& vis,
-    //                                    basic_format_arg<Ctx> arg);           // exposition only
-
-    friend auto get_value(basic_format_arg arg) {
-      return arg.value;
-    }
-
-    template <typename T, typename Char> friend struct detail::formatter;
-
-    template<class Ctx, class... Args>
-      friend format_arg_store<Ctx, Args...>
-        make_format_args(const Args&... args);                           // exposition only
-
-  public:
-    basic_format_arg() noexcept;
-
-    explicit operator bool() const noexcept;
-  };
-}
-
-namespace std {
-template<class Context>
-basic_format_arg<Context>::basic_format_arg() noexcept {}
-
-template<class Context>
-template<class T, typename> /* explicit */ basic_format_arg<Context>::basic_format_arg(const T& v) noexcept {
-  if constexpr (std::is_same_v<T, bool> || std::is_same_v<T, char_type>)
-    value = v;
-  else if constexpr (std::is_same_v<T, char> && std::is_same_v<char_type, wchar_t>)
-    value = static_cast<wchar_t>(v);
-  else if constexpr (detail::is_standard_integer_v<T> && sizeof(T) <= sizeof(int))
-    value = static_cast<int>(v);
-  else if constexpr (detail::is_standard_unsigned_integer_v<T> && sizeof(T) <= sizeof(unsigned))
-    value = static_cast<unsigned>(v);
-  else if constexpr (detail::is_standard_integer_v<T>)
-    value = static_cast<long long int>(v);
-  else if constexpr (detail::is_standard_unsigned_integer_v<T>)
-    value = static_cast<unsigned long long int>(v);
-  else if constexpr (sizeof(typename Context::template formatter_type<T>().format(declval<const T&>(), declval<Context&>())) != 0)
-    value = handle(v);
-}
-
-template<class Context>
-/* explicit */ basic_format_arg<Context>::basic_format_arg(float n) noexcept
-  : value(static_cast<double>(n)) {}
-
-template<class Context>
-/* explicit */ basic_format_arg<Context>::basic_format_arg(double n) noexcept
-  : value(n) {}
-
-template<class Context>
-/* explicit */ basic_format_arg<Context>::basic_format_arg(long double n) noexcept
-  : value(n) {}
-
-template<class Context>
-/* explicit */ basic_format_arg<Context>::basic_format_arg(const typename basic_format_arg<Context>::char_type* s)
-  : value(s) {
-  assert(s != nullptr);
-}
-
-template<class Context>
-template<class traits>
-/* explicit */ basic_format_arg<Context>::basic_format_arg(basic_string_view<char_type, traits> s) noexcept
-  : value(s) {}
-
-template<class Context>
-template<class traits, class Allocator>
-/* explicit */ basic_format_arg<Context>::basic_format_arg(
-    const basic_string<char_type, traits, Allocator>& s) noexcept
-  : value(basic_string_view<char_type>(s.data(), s.size())) {}
-
-
-template<class Context>
-/* explicit */ basic_format_arg<Context>::basic_format_arg(nullptr_t) noexcept
-  : value(static_cast<const void*>(nullptr)) {}
-
-template<class Context>
-template<class T, typename> /* explicit */ basic_format_arg<Context>::basic_format_arg(const T* p) noexcept
-  : value(p) {}
-
-template<class Context>
-/* explicit */ basic_format_arg<Context>::operator bool() const noexcept {
-    return !holds_alternative<monostate>(value);
-}
-}
-
-namespace std {
-  template<class Context>
-  class basic_format_arg<Context>::handle {
-    const void* ptr_;                                         // exposition only
-    void (*format_)(basic_format_parse_context<char_type>&,
-                    Context&, const void*);                   // exposition only
-
-    template<class T> explicit handle(const T& val) noexcept; // exposition only
-
-    friend class basic_format_arg<Context>;                   // exposition only
-
-  public:
-    void format(basic_format_parse_context<char_type>&, Context& ctx) const;
-  };
-}
-
-namespace std {
-template<class Context>
-template<class T> /* explicit */ basic_format_arg<Context>::handle::handle(const T& val) noexcept
-  : ptr_(&val), format_([](basic_format_parse_context<char_type>& parse_ctx, Context& format_ctx, const void* ptr) {
-    typename Context::template formatter_type<T> f;
-    parse_ctx.advance_to(f.parse(parse_ctx));
-    format_ctx.advance_to(f.format(*static_cast<const T*>(ptr), format_ctx));
-  }) {}
-
-template<class Context>
-void basic_format_arg<Context>::handle::format(basic_format_parse_context<char_type>& parse_ctx, Context& format_ctx) const {
-  format_(parse_ctx, format_ctx, ptr_);
-}
-
-// https://fmt.dev/Text%20Formatting.html#format.visit
-template<class Visitor, class Context>
-  auto visit_format_arg(Visitor&& vis, basic_format_arg<Context> arg) {
-    return visit(vis, get_value(arg));
-  }
-}
-
-// https://fmt.dev/Text%20Formatting.html#format.store
-namespace std {
-  template<class Context, class... Args>
-  struct format_arg_store { // exposition only
-    array<basic_format_arg<Context>, sizeof...(Args)> args;
-  };
-}
-
-// https://fmt.dev/Text%20Formatting.html#format.basic_args
-namespace std {
-  template<class Context>
-  class basic_format_args {
-    size_t size_;                           // exposition only
-    const basic_format_arg<Context>* data_; // exposition only
-
-  public:
-    basic_format_args() noexcept;
-
-    template<class... Args>
-      basic_format_args(const format_arg_store<Context, Args...>& store) noexcept;
-
-    basic_format_arg<Context> get(size_t i) const noexcept;
-  };
-}
-
-namespace std {
-
-template<class Context>
-basic_format_args<Context>::basic_format_args() noexcept : size_(0) {}
-
-template<class Context>
-template<class... Args>
-  basic_format_args<Context>::basic_format_args(const format_arg_store<Context, Args...>& store) noexcept
-  : size_(sizeof...(Args)), data_(store.args.data()) {}
-
-template<class Context>
-basic_format_arg<Context> basic_format_args<Context>::get(size_t i) const noexcept {
-  return i < size_ ? data_[i] : basic_format_arg<Context>();
-}
-}
-
-namespace std {
-// https://fmt.dev/Text%20Formatting.html#format.make_args
-template<class Context /*= format_context*/, class... Args>
-  format_arg_store<Context, Args...> make_format_args(const Args&... args) {
-    return {basic_format_arg<Context>(args)...};
-  }
-
-// https://fmt.dev/Text%20Formatting.html#format.make_wargs
-template<class... Args>
-  format_arg_store<wformat_context, Args...> make_wformat_args(const Args&... args) {
-    return make_format_args<wformat_context>(args...);
-  }
-}
-
-namespace std {
-namespace detail {
-
-template <typename OutputIt, typename Char>
-class arg_formatter
-    : public fmt::detail::arg_formatter_base<OutputIt, Char, error_handler> {
- private:
-  using char_type = Char;
-  using base = fmt::detail::arg_formatter_base<OutputIt, Char, error_handler>;
-  using format_context = std::basic_format_context<OutputIt, Char>;
-  using parse_context = basic_format_parse_context<Char>;
-
-  parse_context* parse_ctx_;
-  format_context& ctx_;
-
- public:
-  using iterator = OutputIt;
-  using format_specs = typename base::format_specs;
-
-  /**
-    \rst
-    Constructs an argument formatter object.
-    *ctx* is a reference to the formatting context,
-    *spec* contains format specifier information for standard argument types.
-    \endrst
-   */
-  arg_formatter(format_context& ctx, parse_context* parse_ctx = nullptr, fmt::format_specs* spec = nullptr)
-      : base(ctx.out(), spec, {}), parse_ctx_(parse_ctx), ctx_(ctx) {}
-
-  using base::operator();
-
-  /** Formats an argument of a user-defined type. */
-  iterator operator()(typename std::basic_format_arg<format_context>::handle handle) {
-    handle.format(*parse_ctx_, ctx_);
-    return this->out();
-  }
-
-  iterator operator()(monostate) {
-    throw format_error("");
-  }
-};
-
-template <typename Context>
-inline fmt::detail::type get_type(basic_format_arg<Context> arg) {
-  return visit_format_arg([&] (auto val) {
-    using char_type = typename Context::char_type;
-    using T = decltype(val);
-    if (std::is_same_v<T, monostate>)
-      return fmt::detail::type::none_type;
-    if (std::is_same_v<T, bool>)
-      return fmt::detail::type::bool_type;
-    if (std::is_same_v<T, char_type>)
-      return fmt::detail::type::char_type;
-    if (std::is_same_v<T, int>)
-      return fmt::detail::type::int_type;
-    if (std::is_same_v<T, unsigned int>)
-      return fmt::detail::type::uint_type;
-    if (std::is_same_v<T, long long int>)
-      return fmt::detail::type::long_long_type;
-    if (std::is_same_v<T, unsigned long long int>)
-      return fmt::detail::type::ulong_long_type;
-    if (std::is_same_v<T, double>)
-      return fmt::detail::type::double_type;
-    if (std::is_same_v<T, long double>)
-      return fmt::detail::type::long_double_type;
-    if (std::is_same_v<T, const char_type*>)
-      return fmt::detail::type::cstring_type;
-    if (std::is_same_v<T, basic_string_view<char_type>>)
-      return fmt::detail::type::string_type;
-    if (std::is_same_v<T, const void*>)
-      return fmt::detail::type::pointer_type;
-    assert(get_value(arg).index() == 12);
-    return fmt::detail::type::custom_type;
-  }, arg);
-}
-
-template <typename Context>
-class custom_formatter {
- private:
-  using parse_context = basic_format_parse_context<typename Context::char_type>;
-  parse_context& parse_ctx_;
-  Context& format_ctx_;
-
- public:
-  custom_formatter(parse_context& parse_ctx, Context& ctx) : parse_ctx_(parse_ctx), format_ctx_(ctx) {}
-
-  bool operator()(typename basic_format_arg<Context>::handle h) const {
-    h.format(parse_ctx_, format_ctx_);
-    return true;
-  }
-
-  template <typename T> bool operator()(T) const { return false; }
-};
-
-template <typename ArgFormatter, typename Char, typename Context>
-struct format_handler : detail::error_handler {
-  using iterator = typename ArgFormatter::iterator;
-
-  format_handler(iterator out, basic_string_view<Char> str,
-                 basic_format_args<Context> format_args,
-                 fmt::detail::locale_ref loc)
-      : parse_ctx(str), context(out, format_args, loc) {}
-
-  void on_text(const Char* begin, const Char* end) {
-    auto size = fmt::detail::to_unsigned(end - begin);
-    auto out = context.out();
-    auto&& it = fmt::detail::reserve(out, size);
-    it = std::copy_n(begin, size, it);
-    context.advance_to(out);
-  }
-
-  int on_arg_id() { return parse_ctx.next_arg_id(); }
-  int on_arg_id(unsigned id) { return parse_ctx.check_arg_id(id), id; }
-  int on_arg_id(fmt::basic_string_view<Char>) { return 0; }
-
-  void on_replacement_field(int id, const Char* p) {
-    auto arg = context.arg(id);
-    parse_ctx.advance_to(parse_ctx.begin() + (p  - &*parse_ctx.begin()));
-    custom_formatter<Context> f(parse_ctx, context);
-    if (!visit_format_arg(f, arg))
-      context.advance_to(visit_format_arg(ArgFormatter(context, &parse_ctx), arg));
-  }
-
-  const Char* on_format_specs(int id, const Char* begin, const Char* end) {
-    auto arg = context.arg(id);
-    parse_ctx.advance_to(parse_ctx.begin() + (begin - &*parse_ctx.begin()));
-    custom_formatter<Context> f(parse_ctx, context);
-    if (visit_format_arg(f, arg)) return &*parse_ctx.begin();
-    fmt::basic_format_specs<Char> specs;
-    using fmt::detail::specs_handler;
-    using parse_context = basic_format_parse_context<Char>;
-    fmt::detail::specs_checker<specs_handler<parse_context, Context>> handler(
-        specs_handler<parse_context, Context>(specs, parse_ctx, context), get_type(arg));
-    begin = parse_format_specs(begin, end, handler);
-    if (begin == end || *begin != '}') on_error("missing '}' in format string");
-    parse_ctx.advance_to(parse_ctx.begin() + (begin - &*parse_ctx.begin()));
-    context.advance_to(visit_format_arg(ArgFormatter(context, &parse_ctx, &specs), arg));
-    return begin;
-  }
-
-  basic_format_parse_context<Char> parse_ctx;
-  Context context;
-};
-
-template <typename T, typename Char>
-struct formatter {
-  // Parses format specifiers stopping either at the end of the range or at the
-  // terminating '}'.
-  template <typename ParseContext>
-  FMT_CONSTEXPR typename ParseContext::iterator parse(ParseContext& ctx) {
-    namespace detail = fmt::detail;
-    typedef detail::dynamic_specs_handler<ParseContext> handler_type;
-    auto type = detail::mapped_type_constant<T, fmt::buffer_context<Char>>::value;
-    detail::specs_checker<handler_type> handler(handler_type(specs_, ctx),
-                                                  type);
-    auto it = parse_format_specs(ctx.begin(), ctx.end(), handler);
-    auto type_spec = specs_.type;
-    auto eh = ctx.error_handler();
-    switch (type) {
-    case detail::type::none_type:
-      FMT_ASSERT(false, "invalid argument type");
-      break;
-    case detail::type::int_type:
-    case detail::type::uint_type:
-    case detail::type::long_long_type:
-    case detail::type::ulong_long_type:
-    case detail::type::bool_type:
-      handle_int_type_spec(type_spec,
-                           detail::int_type_checker<decltype(eh)>(eh));
-      break;
-    case detail::type::char_type:
-      handle_char_specs(
-          &specs_, detail::char_specs_checker<decltype(eh)>(type_spec, eh));
-      break;
-    case detail::type::double_type:
-    case detail::type::long_double_type:
-      detail::parse_float_type_spec(specs_, eh);
-      break;
-    case detail::type::cstring_type:
-      detail::handle_cstring_type_spec(
-          type_spec, detail::cstring_type_checker<decltype(eh)>(eh));
-      break;
-    case detail::type::string_type:
-      detail::check_string_type_spec(type_spec, eh);
-      break;
-    case detail::type::pointer_type:
-      detail::check_pointer_type_spec(type_spec, eh);
-      break;
-    case detail::type::custom_type:
-      // Custom format specifiers should be checked in parse functions of
-      // formatter specializations.
-      break;
-    }
-    return it;
-  }
-
-  template <typename FormatContext>
-  auto format(const T& val, FormatContext& ctx) -> decltype(ctx.out()) {
-    fmt::detail::handle_dynamic_spec<fmt::detail::width_checker>(
-        specs_.width, specs_.width_ref, ctx);
-    fmt::detail::handle_dynamic_spec<fmt::detail::precision_checker>(
-        specs_.precision, specs_.precision_ref, ctx);
-    using af = arg_formatter<typename FormatContext::iterator,
-                             typename FormatContext::char_type>;
-    return visit_format_arg(af(ctx, nullptr, &specs_),
-                            basic_format_arg<FormatContext>(val));
-  }
-
- private:
-  fmt::detail::dynamic_format_specs<Char> specs_;
-};
-}  // namespace detail
-
-// https://fmt.dev/Text%20Formatting.html#format.functions
-template<class... Args>
-  string format(string_view fmt, const Args&... args) {
-    return vformat(fmt, make_format_args(args...));
-  }
-
-template<class... Args>
-  wstring format(wstring_view fmt, const Args&... args) {
-    return vformat(fmt, make_wformat_args(args...));
-  }
-
-string vformat(string_view fmt, format_args args) {
-  fmt::memory_buffer mbuf;
-  fmt::detail::buffer<char>& buf = mbuf;
-  using af = detail::arg_formatter<fmt::format_context::iterator, char>;
-  detail::format_handler<af, char, format_context>
-    h(std::back_inserter(buf), fmt, args, {});
-  fmt::detail::parse_format_string<false>(fmt::to_string_view(fmt), h);
-  return to_string(mbuf);
-}
-
-wstring vformat(wstring_view fmt, wformat_args args);
-
-template<class Out, class... Args>
-  Out format_to(Out out, string_view fmt, const Args&... args) {
-    using context = basic_format_context<Out, decltype(fmt)::value_type>;
-    return vformat_to(out, fmt, make_format_args<context>(args...));
-  }
-
-template<class Out, class... Args>
-  Out format_to(Out out, wstring_view fmt, const Args&... args) {
-    using context = basic_format_context<Out, decltype(fmt)::value_type>;
-    return vformat_to(out, fmt, make_format_args<context>(args...));
-  }
-
-template<class Out>
-  Out vformat_to(Out out, string_view fmt, format_args_t<fmt::type_identity_t<Out>, char> args) {
-    using af = detail::arg_formatter<Out, char>;
-    detail::format_handler<af, char, basic_format_context<Out, char>>
-      h(out, fmt, args, {});
-    fmt::detail::parse_format_string<false>(fmt::to_string_view(fmt), h);
-    return h.context.out();
-  }
-
-template<class Out>
-  Out vformat_to(Out out, wstring_view fmt, format_args_t<fmt::type_identity_t<Out>, wchar_t> args);
-
-template<class Out, class... Args>
-  format_to_n_result<Out> format_to_n(Out out, iter_difference_t<Out> n,
-                                      string_view fmt, const Args&... args);
-template<class Out, class... Args>
-  format_to_n_result<Out> format_to_n(Out out, iter_difference_t<Out> n,
-                                      wstring_view fmt, const Args&... args);
-
-template<class... Args>
-  size_t formatted_size(string_view fmt, const Args&... args);
-template<class... Args>
-  size_t formatted_size(wstring_view fmt, const Args&... args);
-
-#define charT char
-
-template<> struct formatter<charT, charT> : detail::formatter<charT, charT> {};
-
-template<> struct formatter<char, wchar_t>;
-
-template<> struct formatter<charT*, charT> : detail::formatter<const charT*, charT> {};
-
-template<> struct formatter<const charT*, charT> : detail::formatter<const charT*, charT> {};
-
-template<size_t N> struct formatter<const charT[N], charT>
-      : detail::formatter<std::basic_string_view<charT>, charT> {};
-
-template<class traits, class Allocator>
-  struct formatter<basic_string<charT, traits, Allocator>, charT>
-      : detail::formatter<std::basic_string_view<charT>, charT> {};
-
-template<class traits>
-  struct formatter<basic_string_view<charT, traits>, charT>
-      : detail::formatter<std::basic_string_view<charT>, charT> {};
-
-template <> struct formatter<nullptr_t, charT> : detail::formatter<const void*, charT> {};
-template <> struct formatter<void*, charT> : detail::formatter<const void*, charT> {};
-template <> struct formatter<const void*, charT> : detail::formatter<const void*, charT> {};
-template <> struct formatter<bool, charT> : detail::formatter<bool, charT> {};
-
-template <> struct formatter<signed char, charT> : detail::formatter<int, charT> {};
-template <> struct formatter<short, charT> : detail::formatter<int, charT> {};
-template <> struct formatter<int, charT> : detail::formatter<int, charT> {};
-template <> struct formatter<long, charT>
-      : detail::formatter<std::conditional_t<sizeof(long) == sizeof(int), int, long long>, charT> {};
-template <> struct formatter<long long, charT> : detail::formatter<long long, charT> {};
-template <> struct formatter<unsigned char, charT> : detail::formatter<unsigned int, charT> {};
-template <> struct formatter<unsigned short, charT> : detail::formatter<unsigned int, charT> {};
-template <> struct formatter<unsigned int, charT> : detail::formatter<unsigned int, charT> {};
-template <> struct formatter<unsigned long, charT>
-      : detail::formatter<std::conditional_t<sizeof(long) == sizeof(int), unsigned, unsigned long long>, charT> {};
-template <> struct formatter<unsigned long long, charT> : detail::formatter<unsigned long long, charT> {};
-
-template <> struct formatter<float, charT> : detail::formatter<double, charT> {};
-template <> struct formatter<double, charT> : detail::formatter<double, charT> {};
-template <> struct formatter<long double, charT> : detail::formatter<long double, charT> {};
-
-#undef charT
-
-#define charT wchar_t
-
-template<> struct formatter<charT, charT> : detail::formatter<charT, charT> {};
-
-template<> struct formatter<char, wchar_t> : detail::formatter<charT, charT> {};
-
-template<> struct formatter<charT*, charT> : detail::formatter<const charT*, charT> {};
-
-template<> struct formatter<const charT*, charT> : detail::formatter<const charT*, charT> {};
-
-template<size_t N> struct formatter<const charT[N], charT>
-      : detail::formatter<std::basic_string_view<charT>, charT> {};
-
-template<class traits, class Allocator>
-  struct formatter<std::basic_string<charT, traits, Allocator>, charT>
-      : detail::formatter<std::basic_string_view<charT>, charT> {};
-
-template<class traits>
-  struct formatter<std::basic_string_view<charT, traits>, charT>
-      : detail::formatter<std::basic_string_view<charT>, charT> {};
-
-template <> struct formatter<nullptr_t, charT> : detail::formatter<const void*, charT> {};
-template <> struct formatter<void*, charT> : detail::formatter<const void*, charT> {};
-template <> struct formatter<const void*, charT> : detail::formatter<const void*, charT> {};
-template <> struct formatter<bool, charT> : detail::formatter<bool, charT> {};
-
-template <> struct formatter<signed char, charT> : detail::formatter<int, charT> {};
-template <> struct formatter<short, charT> : detail::formatter<int, charT> {};
-template <> struct formatter<int, charT> : detail::formatter<int, charT> {};
-template <> struct formatter<long, charT>
-      : detail::formatter<std::conditional_t<sizeof(long) == sizeof(int), int, long long>, charT> {};
-template <> struct formatter<long long, charT> : detail::formatter<long long, charT> {};
-template <> struct formatter<unsigned char, charT> : detail::formatter<unsigned int, charT> {};
-template <> struct formatter<unsigned short, charT> : detail::formatter<unsigned int, charT> {};
-template <> struct formatter<unsigned int, charT> : detail::formatter<unsigned int, charT> {};
-template <> struct formatter<unsigned long, charT>
-      : detail::formatter<std::conditional_t<sizeof(long) == sizeof(int), unsigned, unsigned long long>, charT> {};
-template <> struct formatter<unsigned long long, charT> : detail::formatter<unsigned long long, charT> {};
-
-template <> struct formatter<float, charT> : detail::formatter<double, charT> {};
-template <> struct formatter<double, charT> : detail::formatter<double, charT> {};
-template <> struct formatter<long double, charT> : detail::formatter<long double, charT> {};
-
-#undef charT
-
-  template<> struct formatter<const wchar_t, char> {
-    formatter() = delete;
-  };
-}
-
-#endif  // FMT_FORMAT_

test/format-dyn-args-test.cc

@@ -1,6 +0,0 @@
-// Copyright (c) 2020 Vladimir Solontsov
-// SPDX-License-Identifier: MIT Licence
-
-#include <fmt/core.h>
-
-#include "gtest-extra.h"

test/format-impl-test.cc

@@ -5,21 +5,16 @@
 //
 // For the license information refer to format.h.
 
-#define FMT_NOEXCEPT
-#undef FMT_SHARED
-#include "test-assert.h"
-
-// Include format.cc instead of format.h to test implementation.
 #include <algorithm>
 #include <cstring>
 
-#include "../src/format.cc"
-#include "fmt/printf.h"
-#include "gmock.h"
-#include "gtest-extra.h"
-#include "util.h"
+// clang-format off
+#include "test-assert.h"
+// clang-format on
 
-#undef max
+#include "fmt/format.h"
+#include "gmock/gmock.h"
+#include "util.h"
 
 using fmt::detail::bigint;
 using fmt::detail::fp;
@@ -28,13 +23,13 @@ using fmt::detail::max_value;
 static_assert(!std::is_copy_constructible<bigint>::value, "");
 static_assert(!std::is_copy_assignable<bigint>::value, "");
 
-TEST(BigIntTest, Construct) {
-  EXPECT_EQ("", fmt::format("{}", bigint()));
-  EXPECT_EQ("42", fmt::format("{}", bigint(0x42)));
-  EXPECT_EQ("123456789abcedf0", fmt::format("{}", bigint(0x123456789abcedf0)));
+TEST(bigint_test, construct) {
+  EXPECT_EQ(fmt::to_string(bigint()), "");
+  EXPECT_EQ(fmt::to_string(bigint(0x42)), "42");
+  EXPECT_EQ(fmt::to_string(bigint(0x123456789abcedf0)), "123456789abcedf0");
 }
 
-TEST(BigIntTest, Compare) {
+TEST(bigint_test, compare) {
   bigint n1(42);
   bigint n2(42);
   EXPECT_EQ(compare(n1, n2), 0);
@@ -48,7 +43,7 @@ TEST(BigIntTest, Compare) {
   EXPECT_GT(compare(n4, n2), 0);
 }
 
-TEST(BigIntTest, AddCompare) {
+TEST(bigint_test, add_compare) {
   EXPECT_LT(
       add_compare(bigint(0xffffffff), bigint(0xffffffff), bigint(1) <<= 64), 0);
   EXPECT_LT(add_compare(bigint(1) <<= 32, bigint(1), bigint(1) <<= 96), 0);
@@ -74,80 +69,73 @@ TEST(BigIntTest, AddCompare) {
             0);
 }
 
-TEST(BigIntTest, ShiftLeft) {
+TEST(bigint_test, shift_left) {
   bigint n(0x42);
   n <<= 0;
-  EXPECT_EQ("42", fmt::format("{}", n));
+  EXPECT_EQ(fmt::to_string(n), "42");
   n <<= 1;
-  EXPECT_EQ("84", fmt::format("{}", n));
+  EXPECT_EQ(fmt::to_string(n), "84");
   n <<= 25;
-  EXPECT_EQ("108000000", fmt::format("{}", n));
+  EXPECT_EQ(fmt::to_string(n), "108000000");
 }
 
-TEST(BigIntTest, Multiply) {
+TEST(bigint_test, multiply) {
   bigint n(0x42);
   EXPECT_THROW(n *= 0, assertion_failure);
   n *= 1;
-  EXPECT_EQ("42", fmt::format("{}", n));
+  EXPECT_EQ(fmt::to_string(n), "42");
+
   n *= 2;
-  EXPECT_EQ("84", fmt::format("{}", n));
+  EXPECT_EQ(fmt::to_string(n), "84");
   n *= 0x12345678;
-  EXPECT_EQ("962fc95e0", fmt::format("{}", n));
+  EXPECT_EQ(fmt::to_string(n), "962fc95e0");
+
   bigint bigmax(max_value<uint32_t>());
   bigmax *= max_value<uint32_t>();
-  EXPECT_EQ("fffffffe00000001", fmt::format("{}", bigmax));
-  bigmax.assign(max_value<uint64_t>());
-  bigmax *= max_value<uint64_t>();
-  EXPECT_EQ("fffffffffffffffe0000000000000001", fmt::format("{}", bigmax));
+  EXPECT_EQ(fmt::to_string(bigmax), "fffffffe00000001");
+
+  const auto max64 = max_value<uint64_t>();
+  bigmax = max64;
+  bigmax *= max64;
+  EXPECT_EQ(fmt::to_string(bigmax), "fffffffffffffffe0000000000000001");
+
+  const auto max128 = (fmt::detail::uint128_t(max64) << 64) | max64;
+  bigmax = max128;
+  bigmax *= max128;
+  EXPECT_EQ(fmt::to_string(bigmax),
+            "fffffffffffffffffffffffffffffffe00000000000000000000000000000001");
 }
 
-TEST(BigIntTest, Accumulator) {
-  fmt::detail::accumulator acc;
-  EXPECT_EQ(acc.lower, 0);
-  EXPECT_EQ(acc.upper, 0);
-  acc.upper = 12;
-  acc.lower = 34;
-  EXPECT_EQ(static_cast<uint32_t>(acc), 34);
-  acc += 56;
-  EXPECT_EQ(acc.lower, 90);
-  acc += fmt::detail::max_value<uint64_t>();
-  EXPECT_EQ(acc.upper, 13);
-  EXPECT_EQ(acc.lower, 89);
-  acc >>= 32;
-  EXPECT_EQ(acc.upper, 0);
-  EXPECT_EQ(acc.lower, 13 * 0x100000000);
-}
-
-TEST(BigIntTest, Square) {
+TEST(bigint_test, square) {
   bigint n0(0);
   n0.square();
-  EXPECT_EQ("0", fmt::format("{}", n0));
+  EXPECT_EQ(fmt::to_string(n0), "0");
   bigint n1(0x100);
   n1.square();
-  EXPECT_EQ("10000", fmt::format("{}", n1));
+  EXPECT_EQ(fmt::to_string(n1), "10000");
   bigint n2(0xfffffffff);
   n2.square();
-  EXPECT_EQ("ffffffffe000000001", fmt::format("{}", n2));
+  EXPECT_EQ(fmt::to_string(n2), "ffffffffe000000001");
   bigint n3(max_value<uint64_t>());
   n3.square();
-  EXPECT_EQ("fffffffffffffffe0000000000000001", fmt::format("{}", n3));
+  EXPECT_EQ(fmt::to_string(n3), "fffffffffffffffe0000000000000001");
   bigint n4;
   n4.assign_pow10(10);
-  EXPECT_EQ("2540be400", fmt::format("{}", n4));
+  EXPECT_EQ(fmt::to_string(n4), "2540be400");
 }
 
-TEST(BigIntTest, DivModAssignZeroDivisor) {
+TEST(bigint_test, divmod_assign_zero_divisor) {
   bigint zero(0);
   EXPECT_THROW(bigint(0).divmod_assign(zero), assertion_failure);
   EXPECT_THROW(bigint(42).divmod_assign(zero), assertion_failure);
 }
 
-TEST(BigIntTest, DivModAssignSelf) {
+TEST(bigint_test, divmod_assign_self) {
   bigint n(100);
   EXPECT_THROW(n.divmod_assign(n), assertion_failure);
 }
 
-TEST(BigIntTest, DivModAssignUnaligned) {
+TEST(bigint_test, divmod_assign_unaligned) {
   // (42 << 340) / pow(10, 100):
   bigint n1(42);
   n1 <<= 340;
@@ -155,28 +143,28 @@ TEST(BigIntTest, DivModAssignUnaligned) {
   n2.assign_pow10(100);
   int result = n1.divmod_assign(n2);
   EXPECT_EQ(result, 9406);
-  EXPECT_EQ("10f8353019583bfc29ffc8f564e1b9f9d819dbb4cf783e4507eca1539220p96",
-            fmt::format("{}", n1));
+  EXPECT_EQ(fmt::to_string(n1),
+            "10f8353019583bfc29ffc8f564e1b9f9d819dbb4cf783e4507eca1539220p96");
 }
 
-TEST(BigIntTest, DivModAssign) {
+TEST(bigint_test, divmod_assign) {
   // 100 / 10:
   bigint n1(100);
   int result = n1.divmod_assign(bigint(10));
   EXPECT_EQ(result, 10);
-  EXPECT_EQ("0", fmt::format("{}", n1));
+  EXPECT_EQ(fmt::to_string(n1), "0");
   // pow(10, 100) / (42 << 320):
   n1.assign_pow10(100);
   result = n1.divmod_assign(bigint(42) <<= 320);
   EXPECT_EQ(result, 111);
-  EXPECT_EQ("13ad2594c37ceb0b2784c4ce0bf38ace408e211a7caab24308a82e8f10p96",
-            fmt::format("{}", n1));
+  EXPECT_EQ(fmt::to_string(n1),
+            "13ad2594c37ceb0b2784c4ce0bf38ace408e211a7caab24308a82e8f10p96");
   // 42 / 100:
   bigint n2(42);
   n1.assign_pow10(2);
   result = n2.divmod_assign(n1);
   EXPECT_EQ(result, 0);
-  EXPECT_EQ("2a", fmt::format("{}", n2));
+  EXPECT_EQ(fmt::to_string(n2), "2a");
 }
 
 template <bool is_iec559> void run_double_tests() {
@@ -186,70 +174,20 @@ template <bool is_iec559> void run_double_tests() {
 template <> void run_double_tests<true>() {
   // Construct from double.
   EXPECT_EQ(fp(1.23), fp(0x13ae147ae147aeu, -52));
-
-  // Compute boundaries:
-  fp value;
-  // Normalized & not power of 2 - equidistant boundaries:
-  auto b = value.assign_with_boundaries(1.23);
-  EXPECT_EQ(value, fp(0x0013ae147ae147ae, -52));
-  EXPECT_EQ(b.lower, 0x9d70a3d70a3d6c00);
-  EXPECT_EQ(b.upper, 0x9d70a3d70a3d7400);
-  // Normalized power of 2 - lower boundary is closer:
-  b = value.assign_with_boundaries(1.9807040628566084e+28);  // 2**94
-  EXPECT_EQ(value, fp(0x0010000000000000, 42));
-  EXPECT_EQ(b.lower, 0x7ffffffffffffe00);
-  EXPECT_EQ(b.upper, 0x8000000000000400);
-  // Smallest normalized double - equidistant boundaries:
-  b = value.assign_with_boundaries(2.2250738585072014e-308);
-  EXPECT_EQ(value, fp(0x0010000000000000, -1074));
-  EXPECT_EQ(b.lower, 0x7ffffffffffffc00);
-  EXPECT_EQ(b.upper, 0x8000000000000400);
-  // Subnormal - equidistant boundaries:
-  b = value.assign_with_boundaries(4.9406564584124654e-324);
-  EXPECT_EQ(value, fp(0x0000000000000001, -1074));
-  EXPECT_EQ(b.lower, 0x4000000000000000);
-  EXPECT_EQ(b.upper, 0xc000000000000000);
 }
 
-TEST(FPTest, DoubleTests) {
+TEST(fp_test, double_tests) {
   run_double_tests<std::numeric_limits<double>::is_iec559>();
 }
 
-TEST(FPTest, Normalize) {
+TEST(fp_test, normalize) {
   const auto v = fp(0xbeef, 42);
   auto normalized = normalize(v);
-  EXPECT_EQ(0xbeef000000000000, normalized.f);
-  EXPECT_EQ(-6, normalized.e);
+  EXPECT_EQ(normalized.f, 0xbeef000000000000);
+  EXPECT_EQ(normalized.e, -6);
 }
 
-TEST(FPTest, ComputeFloatBoundaries) {
-  struct {
-    double x, lower, upper;
-  } tests[] = {
-      // regular
-      {1.5f, 1.4999999403953552, 1.5000000596046448},
-      // boundary
-      {1.0f, 0.9999999701976776, 1.0000000596046448},
-      // min normal
-      {1.1754944e-38f, 1.1754942807573643e-38, 1.1754944208872107e-38},
-      // max subnormal
-      {1.1754942e-38f, 1.1754941406275179e-38, 1.1754942807573643e-38},
-      // min subnormal
-      {1e-45f, 7.006492321624085e-46, 2.1019476964872256e-45},
-  };
-  for (auto test : tests) {
-    fp vlower = normalize(fp(test.lower));
-    fp vupper = normalize(fp(test.upper));
-    vlower.f >>= vupper.e - vlower.e;
-    vlower.e = vupper.e;
-    fp value;
-    auto b = value.assign_float_with_boundaries(test.x);
-    EXPECT_EQ(vlower.f, b.lower);
-    EXPECT_EQ(vupper.f, b.upper);
-  }
-}
-
-TEST(FPTest, Multiply) {
+TEST(fp_test, multiply) {
   auto v = fp(123ULL << 32, 4) * fp(56ULL << 32, 7);
   EXPECT_EQ(v.f, 123u * 56u);
   EXPECT_EQ(v.e, 4 + 7 + 64);
@@ -258,152 +196,34 @@ TEST(FPTest, Multiply) {
   EXPECT_EQ(v.e, 4 + 8 + 64);
 }
 
-TEST(FPTest, GetCachedPower) {
-  typedef std::numeric_limits<double> limits;
-  for (auto exp = limits::min_exponent; exp <= limits::max_exponent; ++exp) {
-    int dec_exp = 0;
-    auto fp = fmt::detail::get_cached_power(exp, dec_exp);
-    EXPECT_LE(exp, fp.e);
-    int dec_exp_step = 8;
-    EXPECT_LE(fp.e, exp + dec_exp_step * log2(10));
-    EXPECT_DOUBLE_EQ(pow(10, dec_exp), ldexp(static_cast<double>(fp.f), fp.e));
-  }
+TEST(fp_test, dragonbox_max_k) {
+  using fmt::detail::dragonbox::floor_log10_pow2;
+  using float_info = fmt::detail::dragonbox::float_info<float>;
+  EXPECT_EQ(
+      fmt::detail::const_check(float_info::max_k),
+      float_info::kappa -
+          floor_log10_pow2(std::numeric_limits<float>::min_exponent -
+                           fmt::detail::num_significand_bits<float>() - 1));
+  using double_info = fmt::detail::dragonbox::float_info<double>;
+  EXPECT_EQ(fmt::detail::const_check(double_info::max_k),
+            double_info::kappa -
+                floor_log10_pow2(
+                    std::numeric_limits<double>::min_exponent -
+                    2 * fmt::detail::num_significand_bits<double>() - 1));
 }
 
-TEST(FPTest, GetRoundDirection) {
-  using fmt::detail::get_round_direction;
-  using fmt::detail::round_direction;
-  EXPECT_EQ(round_direction::down, get_round_direction(100, 50, 0));
-  EXPECT_EQ(round_direction::up, get_round_direction(100, 51, 0));
-  EXPECT_EQ(round_direction::down, get_round_direction(100, 40, 10));
-  EXPECT_EQ(round_direction::up, get_round_direction(100, 60, 10));
-  for (size_t i = 41; i < 60; ++i)
-    EXPECT_EQ(round_direction::unknown, get_round_direction(100, i, 10));
-  uint64_t max = max_value<uint64_t>();
-  EXPECT_THROW(get_round_direction(100, 100, 0), assertion_failure);
-  EXPECT_THROW(get_round_direction(100, 0, 100), assertion_failure);
-  EXPECT_THROW(get_round_direction(100, 0, 50), assertion_failure);
-  // Check that remainder + error doesn't overflow.
-  EXPECT_EQ(round_direction::up, get_round_direction(max, max - 1, 2));
-  // Check that 2 * (remainder + error) doesn't overflow.
-  EXPECT_EQ(round_direction::unknown,
-            get_round_direction(max, max / 2 + 1, max / 2));
-  // Check that remainder - error doesn't overflow.
-  EXPECT_EQ(round_direction::unknown, get_round_direction(100, 40, 41));
-  // Check that 2 * (remainder - error) doesn't overflow.
-  EXPECT_EQ(round_direction::up, get_round_direction(max, max - 1, 1));
-}
-
-TEST(FPTest, FixedHandler) {
-  struct handler : fmt::detail::fixed_handler {
-    char buffer[10];
-    handler(int prec = 0) : fmt::detail::fixed_handler() {
-      buf = buffer;
-      precision = prec;
-    }
-  };
-  int exp = 0;
-  handler().on_digit('0', 100, 99, 0, exp, false);
-  EXPECT_THROW(handler().on_digit('0', 100, 100, 0, exp, false),
-               assertion_failure);
-  namespace digits = fmt::detail::digits;
-  EXPECT_EQ(handler(1).on_digit('0', 100, 10, 10, exp, false), digits::done);
-  // Check that divisor - error doesn't overflow.
-  EXPECT_EQ(handler(1).on_digit('0', 100, 10, 101, exp, false), digits::error);
-  // Check that 2 * error doesn't overflow.
-  uint64_t max = max_value<uint64_t>();
-  EXPECT_EQ(handler(1).on_digit('0', max, 10, max - 1, exp, false),
-            digits::error);
-}
-
-TEST(FPTest, GrisuFormatCompilesWithNonIEEEDouble) {
-  fmt::memory_buffer buf;
-  format_float(0.42, -1, fmt::detail::float_specs(), buf);
-}
-
-template <typename T> struct value_extractor {
-  T operator()(T value) { return value; }
-
-  template <typename U> FMT_NORETURN T operator()(U) {
-    throw std::runtime_error(fmt::format("invalid type {}", typeid(U).name()));
-  }
-
-#if FMT_USE_INT128
-  // Apple Clang does not define typeid for __int128_t and __uint128_t.
-  FMT_NORETURN T operator()(fmt::detail::int128_t) {
-    throw std::runtime_error("invalid type __int128_t");
-  }
-
-  FMT_NORETURN T operator()(fmt::detail::uint128_t) {
-    throw std::runtime_error("invalid type __uint128_t");
-  }
-#endif
-};
-
-TEST(FormatTest, ArgConverter) {
-  long long value = max_value<long long>();
-  auto arg = fmt::detail::make_arg<fmt::format_context>(value);
-  fmt::visit_format_arg(
-      fmt::detail::arg_converter<long long, fmt::format_context>(arg, 'd'),
-      arg);
-  EXPECT_EQ(value, fmt::visit_format_arg(value_extractor<long long>(), arg));
-}
-
-TEST(FormatTest, FormatNegativeNaN) {
-  double nan = std::numeric_limits<double>::quiet_NaN();
-  if (std::signbit(-nan))
-    EXPECT_EQ("-nan", fmt::format("{}", -nan));
-  else
-    fmt::print("Warning: compiler doesn't handle negative NaN correctly");
-}
-
-TEST(FormatTest, StrError) {
-  char* message = nullptr;
-  char buffer[BUFFER_SIZE];
-  EXPECT_ASSERT(fmt::detail::safe_strerror(EDOM, message = nullptr, 0),
-                "invalid buffer");
-  EXPECT_ASSERT(fmt::detail::safe_strerror(EDOM, message = buffer, 0),
-                "invalid buffer");
-  buffer[0] = 'x';
-#if defined(_GNU_SOURCE) && !defined(__COVERITY__)
-  // Use invalid error code to make sure that safe_strerror returns an error
-  // message in the buffer rather than a pointer to a static string.
-  int error_code = -1;
-#else
-  int error_code = EDOM;
-#endif
-
-  int result =
-      fmt::detail::safe_strerror(error_code, message = buffer, BUFFER_SIZE);
-  EXPECT_EQ(result, 0);
-  size_t message_size = std::strlen(message);
-  EXPECT_GE(BUFFER_SIZE - 1u, message_size);
-  EXPECT_EQ(get_system_error(error_code), message);
-
-  // safe_strerror never uses buffer on MinGW.
-#if !defined(__MINGW32__) && !defined(__sun)
-  result =
-      fmt::detail::safe_strerror(error_code, message = buffer, message_size);
-  EXPECT_EQ(ERANGE, result);
-  result = fmt::detail::safe_strerror(error_code, message = buffer, 1);
-  EXPECT_EQ(buffer, message);  // Message should point to buffer.
-  EXPECT_EQ(ERANGE, result);
-  EXPECT_STREQ("", message);
-#endif
-}
-
-TEST(FormatTest, FormatErrorCode) {
+TEST(format_impl_test, format_error_code) {
   std::string msg = "error 42", sep = ": ";
   {
-    fmt::memory_buffer buffer;
-    format_to(buffer, "garbage");
+    auto buffer = fmt::memory_buffer();
+    fmt::format_to(fmt::appender(buffer), "garbage");
     fmt::detail::format_error_code(buffer, 42, "test");
-    EXPECT_EQ("test: " + msg, to_string(buffer));
+    EXPECT_EQ(to_string(buffer), "test: " + msg);
   }
   {
-    fmt::memory_buffer buffer;
-    std::string prefix(fmt::inline_buffer_size - msg.size() - sep.size() + 1,
-                       'x');
+    auto buffer = fmt::memory_buffer();
+    auto prefix =
+        std::string(fmt::inline_buffer_size - msg.size() - sep.size() + 1, 'x');
     fmt::detail::format_error_code(buffer, 42, prefix);
     EXPECT_EQ(msg, to_string(buffer));
   }
@@ -412,7 +232,8 @@ TEST(FormatTest, FormatErrorCode) {
     // Test maximum buffer size.
     msg = fmt::format("error {}", codes[i]);
     fmt::memory_buffer buffer;
-    std::string prefix(fmt::inline_buffer_size - msg.size() - sep.size(), 'x');
+    auto prefix =
+        std::string(fmt::inline_buffer_size - msg.size() - sep.size(), 'x');
     fmt::detail::format_error_code(buffer, codes[i], prefix);
     EXPECT_EQ(prefix + sep + msg, to_string(buffer));
     size_t size = fmt::inline_buffer_size;
@@ -421,13 +242,13 @@ TEST(FormatTest, FormatErrorCode) {
     // Test with a message that doesn't fit into the buffer.
     prefix += 'x';
     fmt::detail::format_error_code(buffer, codes[i], prefix);
-    EXPECT_EQ(msg, to_string(buffer));
+    EXPECT_EQ(to_string(buffer), msg);
   }
 }
 
-TEST(FormatTest, CountCodePoints) {
+TEST(format_impl_test, compute_width) {
   EXPECT_EQ(4,
-            fmt::detail::count_code_points(
+            fmt::detail::compute_width(
                 fmt::basic_string_view<fmt::detail::char8_type>(
                     reinterpret_cast<const fmt::detail::char8_type*>("ёжик"))));
 }
@@ -437,20 +258,226 @@ template <typename Int> void test_count_digits() {
   for (Int i = 0; i < 10; ++i) EXPECT_EQ(1u, fmt::detail::count_digits(i));
   for (Int i = 1, n = 1, end = max_value<Int>() / 10; n <= end; ++i) {
     n *= 10;
-    EXPECT_EQ(i, fmt::detail::count_digits(n - 1));
-    EXPECT_EQ(i + 1, fmt::detail::count_digits(n));
+    EXPECT_EQ(fmt::detail::count_digits(n - 1), i);
+    EXPECT_EQ(fmt::detail::count_digits(n), i + 1);
   }
 }
 
-TEST(UtilTest, CountDigits) {
+TEST(format_impl_test, count_digits) {
   test_count_digits<uint32_t>();
   test_count_digits<uint64_t>();
 }
 
-TEST(UtilTest, WriteFallbackUIntPtr) {
-  std::string s;
-  fmt::detail::write_ptr<char>(
-      std::back_inserter(s),
-      fmt::detail::fallback_uintptr(reinterpret_cast<void*>(0xface)), nullptr);
-  EXPECT_EQ(s, "0xface");
+TEST(format_impl_test, countl_zero) {
+  constexpr auto num_bits = fmt::detail::num_bits<uint32_t>();
+  uint32_t n = 1u;
+  for (int i = 1; i < num_bits - 1; i++) {
+    n <<= 1;
+    EXPECT_EQ(fmt::detail::countl_zero(n - 1), num_bits - i);
+    EXPECT_EQ(fmt::detail::countl_zero(n), num_bits - i - 1);
+  }
+}
+
+#if FMT_USE_FLOAT128
+TEST(format_impl_test, write_float128) {
+  auto s = std::string();
+  fmt::detail::write<char>(std::back_inserter(s), __float128(42));
+  EXPECT_EQ(s, "42");
+}
+#endif
+
+struct double_double {
+  double a;
+  double b;
+
+  explicit constexpr double_double(double a_val = 0, double b_val = 0)
+      : a(a_val), b(b_val) {}
+
+  operator double() const { return a + b; }
+  auto operator-() const -> double_double { return double_double(-a, -b); }
+};
+
+auto format_as(double_double d) -> double { return d; }
+
+bool operator>=(const double_double& lhs, const double_double& rhs) {
+  return lhs.a + lhs.b >= rhs.a + rhs.b;
+}
+
+struct slow_float {
+  float value;
+
+  explicit constexpr slow_float(float val = 0) : value(val) {}
+  operator float() const { return value; }
+  auto operator-() const -> slow_float { return slow_float(-value); }
+};
+
+auto format_as(slow_float f) -> float { return f; }
+
+namespace std {
+template <> struct is_floating_point<double_double> : std::true_type {};
+template <> struct numeric_limits<double_double> {
+  // is_iec559 is true for double-double in libstdc++.
+  static constexpr bool is_iec559 = true;
+  static constexpr int digits = 106;
+};
+
+template <> struct is_floating_point<slow_float> : std::true_type {};
+template <> struct numeric_limits<slow_float> : numeric_limits<float> {};
+}  // namespace std
+
+FMT_BEGIN_NAMESPACE
+namespace detail {
+template <> struct is_fast_float<slow_float> : std::false_type {};
+namespace dragonbox {
+template <> struct float_info<slow_float> {
+  using carrier_uint = uint32_t;
+  static const int exponent_bits = 8;
+};
+}  // namespace dragonbox
+}  // namespace detail
+FMT_END_NAMESPACE
+
+TEST(format_impl_test, write_double_double) {
+  auto s = std::string();
+  fmt::detail::write<char>(std::back_inserter(s), double_double(42), {});
+  // Specializing is_floating_point is broken in MSVC.
+  if (!FMT_MSC_VERSION) EXPECT_EQ(s, "42");
+}
+
+TEST(format_impl_test, write_dragon_even) {
+  auto s = std::string();
+  fmt::detail::write<char>(std::back_inserter(s), slow_float(33554450.0f), {});
+  // Specializing is_floating_point is broken in MSVC.
+  if (!FMT_MSC_VERSION) EXPECT_EQ(s, "33554450");
+}
+
+#ifdef _WIN32
+#  include <windows.h>
+
+TEST(format_impl_test, write_console_signature) {
+  decltype(::WriteConsoleW)* p = fmt::detail::WriteConsoleW;
+  (void)p;
+}
+#endif
+
+// A public domain branchless UTF-8 decoder by Christopher Wellons:
+// https://github.com/skeeto/branchless-utf8
+constexpr bool unicode_is_surrogate(uint32_t c) {
+  return c >= 0xD800U && c <= 0xDFFFU;
+}
+
+FMT_CONSTEXPR char* utf8_encode(char* s, uint32_t c) {
+  if (c >= (1UL << 16)) {
+    s[0] = static_cast<char>(0xf0 | (c >> 18));
+    s[1] = static_cast<char>(0x80 | ((c >> 12) & 0x3f));
+    s[2] = static_cast<char>(0x80 | ((c >> 6) & 0x3f));
+    s[3] = static_cast<char>(0x80 | ((c >> 0) & 0x3f));
+    return s + 4;
+  } else if (c >= (1UL << 11)) {
+    s[0] = static_cast<char>(0xe0 | (c >> 12));
+    s[1] = static_cast<char>(0x80 | ((c >> 6) & 0x3f));
+    s[2] = static_cast<char>(0x80 | ((c >> 0) & 0x3f));
+    return s + 3;
+  } else if (c >= (1UL << 7)) {
+    s[0] = static_cast<char>(0xc0 | (c >> 6));
+    s[1] = static_cast<char>(0x80 | ((c >> 0) & 0x3f));
+    return s + 2;
+  } else {
+    s[0] = static_cast<char>(c);
+    return s + 1;
+  }
+}
+
+// Make sure it can decode every character
+TEST(format_impl_test, utf8_decode_decode_all) {
+  for (uint32_t i = 0; i < 0x10ffff; i++) {
+    if (!unicode_is_surrogate(i)) {
+      int e;
+      uint32_t c;
+      char buf[8] = {0};
+      char* end = utf8_encode(buf, i);
+      const char* res = fmt::detail::utf8_decode(buf, &c, &e);
+      EXPECT_EQ(end, res);
+      EXPECT_EQ(c, i);
+      EXPECT_EQ(e, 0);
+    }
+  }
+}
+
+// Reject everything outside of U+0000..U+10FFFF
+TEST(format_impl_test, utf8_decode_out_of_range) {
+  for (uint32_t i = 0x110000; i < 0x1fffff; i++) {
+    int e;
+    uint32_t c;
+    char buf[8] = {0};
+    utf8_encode(buf, i);
+    const char* end = fmt::detail::utf8_decode(buf, &c, &e);
+    EXPECT_NE(e, 0);
+    EXPECT_EQ(end - buf, 4);
+  }
+}
+
+// Does it reject all surrogate halves?
+TEST(format_impl_test, utf8_decode_surrogate_halves) {
+  for (uint32_t i = 0xd800; i <= 0xdfff; i++) {
+    int e;
+    uint32_t c;
+    char buf[8] = {0};
+    utf8_encode(buf, i);
+    fmt::detail::utf8_decode(buf, &c, &e);
+    EXPECT_NE(e, 0);
+  }
+}
+
+// How about non-canonical encodings?
+TEST(format_impl_test, utf8_decode_non_canonical_encodings) {
+  int e;
+  uint32_t c;
+  const char* end;
+
+  char buf2[8] = {char(0xc0), char(0xA4)};
+  end = fmt::detail::utf8_decode(buf2, &c, &e);
+  EXPECT_NE(e, 0);           // non-canonical len 2
+  EXPECT_EQ(end, buf2 + 2);  // non-canonical recover 2
+
+  char buf3[8] = {char(0xe0), char(0x80), char(0xA4)};
+  end = fmt::detail::utf8_decode(buf3, &c, &e);
+  EXPECT_NE(e, 0);           // non-canonical len 3
+  EXPECT_EQ(end, buf3 + 3);  // non-canonical recover 3
+
+  char buf4[8] = {char(0xf0), char(0x80), char(0x80), char(0xA4)};
+  end = fmt::detail::utf8_decode(buf4, &c, &e);
+  EXPECT_NE(e, 0);           // non-canonical encoding len 4
+  EXPECT_EQ(end, buf4 + 4);  // non-canonical recover 4
+}
+
+// Let's try some bogus byte sequences
+TEST(format_impl_test, utf8_decode_bogus_byte_sequences) {
+  int e;
+  uint32_t c;
+
+  // Invalid first byte
+  char buf0[4] = {char(0xff)};
+  auto len = fmt::detail::utf8_decode(buf0, &c, &e) - buf0;
+  EXPECT_NE(e, 0);    // "bogus [ff] 0x%02x U+%04lx", e, (unsigned long)c);
+  EXPECT_EQ(len, 1);  // "bogus [ff] recovery %d", len);
+
+  // Invalid first byte
+  char buf1[4] = {char(0x80)};
+  len = fmt::detail::utf8_decode(buf1, &c, &e) - buf1;
+  EXPECT_NE(e, 0);    // "bogus [80] 0x%02x U+%04lx", e, (unsigned long)c);
+  EXPECT_EQ(len, 1);  // "bogus [80] recovery %d", len);
+
+  // Looks like a two-byte sequence but second byte is wrong
+  char buf2[4] = {char(0xc0), char(0x0a)};
+  len = fmt::detail::utf8_decode(buf2, &c, &e) - buf2;
+  EXPECT_NE(e, 0);    // "bogus [c0 0a] 0x%02x U+%04lx", e, (unsigned long)c
+  EXPECT_EQ(len, 2);  // "bogus [c0 0a] recovery %d", len);
+}
+
+TEST(format_impl_test, to_utf8) {
+  auto s = std::string("ёжик");
+  auto u = fmt::detail::to_utf8<wchar_t>(L"\x0451\x0436\x0438\x043A");
+  EXPECT_EQ(s, u.str());
+  EXPECT_EQ(s.size(), u.size());
 }

test/fuzzing/CMakeLists.txt

@@ -1,38 +1,30 @@
 # Copyright (c) 2019, Paul Dreik
 # License: see LICENSE.rst in the fmt root directory
 
-# settings this links in a main. useful for reproducing,
-# kcov, gdb, afl, valgrind.
-# (note that libFuzzer can also reproduce, just pass it the files)
-option(FMT_FUZZ_LINKMAIN "enables the reproduce mode, instead of libFuzzer" On)
+# Link in the main function. Useful for reproducing, kcov, gdb, afl, valgrind.
+# (Note that libFuzzer can also reproduce, just pass it the files.)
+option(FMT_FUZZ_LINKMAIN "Enables the reproduce mode, instead of libFuzzer" On)
 
 # For oss-fuzz - insert $LIB_FUZZING_ENGINE into the link flags, but only for
-# the fuzz targets, otherwise the cmake configuration step fails.
+# the fuzz targets, otherwise the CMake configuration step fails.
 set(FMT_FUZZ_LDFLAGS "" CACHE STRING "LDFLAGS for the fuzz targets")
 
-# Find all fuzzers.
-set(SOURCES
-  chrono_duration.cpp
-  named_arg.cpp
-  one_arg.cpp
-  sprintf.cpp
-  two_args.cpp
-)
-
-macro(implement_fuzzer sourcefile)
-  get_filename_component(basename ${sourcefile} NAME_WE)
-  set(name fuzzer_${basename})
-  add_executable(${name} ${sourcefile} fuzzer_common.h)
+# Adds a binary for reproducing, i.e. no fuzzing, just enables replaying data
+# through the fuzzers.
+function(add_fuzzer source)
+  get_filename_component(basename ${source} NAME_WE)
+  set(name ${basename}-fuzzer)
+  add_executable(${name} ${source} fuzzer-common.h)
   if (FMT_FUZZ_LINKMAIN)
-      target_sources(${name} PRIVATE main.cpp)
+    target_sources(${name} PRIVATE main.cc)
   endif ()
   target_link_libraries(${name} PRIVATE fmt)
-if (FMT_FUZZ_LDFLAGS)
-  target_link_libraries(${name} PRIVATE ${FMT_FUZZ_LDFLAGS})
-endif ()
-  target_compile_features(${name} PRIVATE cxx_generic_lambdas)
-endmacro ()
+  if (FMT_FUZZ_LDFLAGS)
+    target_link_libraries(${name} PRIVATE ${FMT_FUZZ_LDFLAGS})
+  endif ()
+  target_compile_features(${name} PRIVATE cxx_std_14)
+endfunction()
 
-foreach (X IN ITEMS ${SOURCES})
-  implement_fuzzer(${X})
+foreach (source chrono-duration.cc chrono-timepoint.cc float.cc named-arg.cc one-arg.cc two-args.cc)
+  add_fuzzer(${source})
 endforeach ()

test/fuzzing/README.md

@@ -1,27 +1,4 @@
-# FMT Fuzzer
-
-Fuzzing has revealed [several bugs](https://github.com/fmtlib/fmt/issues?&q=is%3Aissue+fuzz)
-in fmt. It is a part of the continous fuzzing at
-[oss-fuzz](https://github.com/google/oss-fuzz).
-
-The source code is modified to make the fuzzing possible without locking up on
-resource exhaustion:
-```cpp
-#ifdef FMT_FUZZ
-if(spec.precision>100000) {
-  throw std::runtime_error("fuzz mode - avoiding large precision");
-}
-#endif
-``` 
-This macro `FMT_FUZZ` is enabled on OSS-Fuzz builds and makes fuzzing
-practically possible. It is used in fmt code to prevent resource exhaustion in
-fuzzing mode.  
-The macro `FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION` is the
-defacto standard for making fuzzing practically possible to disable certain
-fuzzing-unfriendly features (for example, randomness), see [the libFuzzer
-documentation](https://llvm.org/docs/LibFuzzer.html#fuzzer-friendly-build-mode).
-
-## Running the fuzzers locally
+# Running the fuzzers locally
 
 There is a [helper script](build.sh) to build the fuzzers, which has only been
 tested on Debian and Ubuntu linux so far. There should be no problems fuzzing on
@@ -34,7 +11,7 @@ mkdir build
 cd build
 export CXX=clang++
 export CXXFLAGS="-fsanitize=fuzzer-no-link -DFUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION= -g"
-cmake ..  -DFMT_SAFE_DURATION_CAST=On -DFMT_FUZZ=On -DFMT_FUZZ_LINKMAIN=Off -DFMT_FUZZ_LDFLAGS="-fsanitize=fuzzer"
+cmake .. -DFMT_SAFE_DURATION_CAST=On -DFMT_FUZZ=On -DFMT_FUZZ_LINKMAIN=Off -DFMT_FUZZ_LDFLAGS="-fsanitize=fuzzer"
 cmake --build .
 ```
 should work to build the fuzzers for all platforms which clang supports.
@@ -44,5 +21,5 @@ Execute a fuzzer with for instance
 cd build
 export UBSAN_OPTIONS=halt_on_error=1
 mkdir out_chrono
-bin/fuzzer_chrono_duration  out_chrono
+bin/fuzzer_chrono_duration out_chrono
 ```

test/fuzzing/build.sh

@@ -1,7 +1,6 @@
 #!/bin/sh
 #
 # Creates fuzzer builds of various kinds
-# - reproduce mode (no fuzzing, just enables replaying data through the fuzzers)
 # - oss-fuzz emulated mode (makes sure a simulated invocation by oss-fuzz works)
 # - libFuzzer build (you will need clang)
 # - afl build (you will need afl)
@@ -9,7 +8,7 @@
 #
 # Copyright (c) 2019 Paul Dreik
 #
-# License: see LICENSE.rst in the fmt root directory
+# For the license information refer to format.h.
 
 set -e
 me=$(basename $0)
@@ -23,16 +22,9 @@ here=$(pwd)
 CXXFLAGSALL="-DFUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION= -g"
 CMAKEFLAGSALL="$root -GNinja -DCMAKE_BUILD_TYPE=Debug -DFMT_DOC=Off -DFMT_TEST=Off -DFMT_FUZZ=On -DCMAKE_CXX_STANDARD=17"
 
-#builds the fuzzers as one would do if using afl or just making
-#binaries for reproducing.
-builddir=$here/build-fuzzers-reproduce
-mkdir -p $builddir
-cd $builddir
-CXX="ccache g++" CXXFLAGS="$CXXFLAGSALL" cmake \
-$CMAKEFLAGSALL
-cmake --build $builddir
+CLANG=clang++-11
 
-#for performance analysis of the fuzzers
+# For performance analysis of the fuzzers.
 builddir=$here/build-fuzzers-perfanalysis
 mkdir -p $builddir
 cd $builddir
@@ -43,11 +35,11 @@ $CMAKEFLAGSALL \
 
 cmake --build $builddir
 
-#builds the fuzzers as oss-fuzz does
+# Builds the fuzzers as oss-fuzz does.
 builddir=$here/build-fuzzers-ossfuzz
 mkdir -p $builddir
 cd $builddir
-CXX="clang++" \
+CXX=$CLANG \
 CXXFLAGS="$CXXFLAGSALL -fsanitize=fuzzer-no-link" cmake \
 cmake $CMAKEFLAGSALL \
 -DFMT_FUZZ_LINKMAIN=Off \
@@ -56,11 +48,11 @@ cmake $CMAKEFLAGSALL \
 cmake --build $builddir
 
 
-#builds fuzzers for local fuzzing with libfuzzer with asan+usan
+# Builds fuzzers for local fuzzing with libfuzzer with asan+usan.
 builddir=$here/build-fuzzers-libfuzzer
 mkdir -p $builddir
 cd $builddir
-CXX="clang++" \
+CXX=$CLANG \
 CXXFLAGS="$CXXFLAGSALL -fsanitize=fuzzer-no-link,address,undefined" cmake \
 cmake $CMAKEFLAGSALL \
 -DFMT_FUZZ_LINKMAIN=Off \
@@ -68,23 +60,11 @@ cmake $CMAKEFLAGSALL \
 
 cmake --build $builddir
 
-#builds fuzzers for local fuzzing with libfuzzer with asan only
-builddir=$here/build-fuzzers-libfuzzer-addr
-mkdir -p $builddir
-cd $builddir
-CXX="clang++" \
-CXXFLAGS="$CXXFLAGSALL -fsanitize=fuzzer-no-link,undefined" cmake \
-cmake $CMAKEFLAGSALL \
--DFMT_FUZZ_LINKMAIN=Off \
--DFMT_FUZZ_LDFLAGS="-fsanitize=fuzzer"
-
-cmake --build $builddir
-
-#builds a fast fuzzer for making coverage fast
+# Builds a fast fuzzer for making coverage fast.
 builddir=$here/build-fuzzers-fast
 mkdir -p $builddir
 cd $builddir
-CXX="clang++" \
+CXX=$CLANG \
 CXXFLAGS="$CXXFLAGSALL -fsanitize=fuzzer-no-link -O3" cmake \
 cmake $CMAKEFLAGSALL \
 -DFMT_FUZZ_LINKMAIN=Off \
@@ -94,7 +74,7 @@ cmake $CMAKEFLAGSALL \
 cmake --build $builddir
 
 
-#builds fuzzers for local fuzzing with afl
+# Builds fuzzers for local fuzzing with afl.
 builddir=$here/build-fuzzers-afl
 mkdir -p $builddir
 cd $builddir

test/fuzzing/chrono-duration.cc

@@ -0,0 +1,136 @@
+// Copyright (c) 2019, Paul Dreik
+// For the license information refer to format.h.
+
+#include <fmt/chrono.h>
+
+#include <cstdint>
+
+#include "fuzzer-common.h"
+
+template <typename Period, typename Rep>
+void invoke_inner(fmt::string_view format_str, Rep rep) {
+  auto value = std::chrono::duration<Rep, Period>(rep);
+  try {
+#if FMT_FUZZ_FORMAT_TO_STRING
+    std::string message = fmt::format(format_str, value);
+#else
+    auto buf = fmt::memory_buffer();
+    fmt::format_to(std::back_inserter(buf), format_str, value);
+#endif
+  } catch (std::exception&) {
+  }
+}
+
+// Rep is a duration's representation type.
+template <typename Rep>
+void invoke_outer(const uint8_t* data, size_t size, int period) {
+  // Always use a fixed location of the data.
+  static_assert(sizeof(Rep) <= fixed_size, "fixed size is too small");
+  if (size <= fixed_size + 1) return;
+
+  const Rep rep = assign_from_buf<Rep>(data);
+  data += fixed_size;
+  size -= fixed_size;
+
+  // data is already allocated separately in libFuzzer so reading past the end
+  // will most likely be detected anyway.
+  const auto format_str = fmt::string_view(as_chars(data), size);
+
+  // yocto, zepto, zetta and yotta are not handled.
+  switch (period) {
+  case 1:
+    invoke_inner<std::atto>(format_str, rep);
+    break;
+  case 2:
+    invoke_inner<std::femto>(format_str, rep);
+    break;
+  case 3:
+    invoke_inner<std::pico>(format_str, rep);
+    break;
+  case 4:
+    invoke_inner<std::nano>(format_str, rep);
+    break;
+  case 5:
+    invoke_inner<std::micro>(format_str, rep);
+    break;
+  case 6:
+    invoke_inner<std::milli>(format_str, rep);
+    break;
+  case 7:
+    invoke_inner<std::centi>(format_str, rep);
+    break;
+  case 8:
+    invoke_inner<std::deci>(format_str, rep);
+    break;
+  case 9:
+    invoke_inner<std::deca>(format_str, rep);
+    break;
+  case 10:
+    invoke_inner<std::kilo>(format_str, rep);
+    break;
+  case 11:
+    invoke_inner<std::mega>(format_str, rep);
+    break;
+  case 12:
+    invoke_inner<std::giga>(format_str, rep);
+    break;
+  case 13:
+    invoke_inner<std::tera>(format_str, rep);
+    break;
+  case 14:
+    invoke_inner<std::peta>(format_str, rep);
+    break;
+  case 15:
+    invoke_inner<std::exa>(format_str, rep);
+    break;
+  }
+}
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
+  if (size <= 4) return 0;
+
+  const auto representation = data[0];
+  const auto period = data[1];
+  data += 2;
+  size -= 2;
+
+  switch (representation) {
+  case 1:
+    invoke_outer<char>(data, size, period);
+    break;
+  case 2:
+    invoke_outer<signed char>(data, size, period);
+    break;
+  case 3:
+    invoke_outer<unsigned char>(data, size, period);
+    break;
+  case 4:
+    invoke_outer<short>(data, size, period);
+    break;
+  case 5:
+    invoke_outer<unsigned short>(data, size, period);
+    break;
+  case 6:
+    invoke_outer<int>(data, size, period);
+    break;
+  case 7:
+    invoke_outer<unsigned int>(data, size, period);
+    break;
+  case 8:
+    invoke_outer<long>(data, size, period);
+    break;
+  case 9:
+    invoke_outer<unsigned long>(data, size, period);
+    break;
+  case 10:
+    invoke_outer<float>(data, size, period);
+    break;
+  case 11:
+    invoke_outer<double>(data, size, period);
+    break;
+  case 12:
+    invoke_outer<long double>(data, size, period);
+    break;
+  }
+  return 0;
+}

test/fuzzing/chrono-timepoint.cc

@@ -0,0 +1,32 @@
+// Copyright (c) 2021, Paul Dreik
+// For license information refer to format.h.
+#include <fmt/chrono.h>
+
+#include "fuzzer-common.h"
+
+/*
+ * a fuzzer for the chrono timepoints formatters
+ * C is a clock (std::chrono::system_clock etc)
+ */
+template <typename C> void doit(const uint8_t* data, size_t size) {
+  using Rep = typename C::time_point::rep;
+  constexpr auto N = sizeof(Rep);
+  if (size < N) return;
+
+  const auto x = assign_from_buf<Rep>(data);
+  typename C::duration dur{x};
+  typename C::time_point timepoint{dur};
+  data += N;
+  size -= N;
+  data_to_string format_str(data, size);
+
+  std::string message = fmt::format(format_str.get(), timepoint);
+}
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
+  try {
+    doit<std::chrono::system_clock>(data, size);
+  } catch (...) {
+  }
+  return 0;
+}

test/fuzzing/chrono_duration.cpp

@@ -1,152 +0,0 @@
-// Copyright (c) 2019, Paul Dreik
-// License: see LICENSE.rst in the fmt root directory
-
-#include <fmt/chrono.h>
-#include <cstdint>
-#include <limits>
-#include <stdexcept>
-#include <type_traits>
-#include <vector>
-#include "fuzzer_common.h"
-
-template <typename Item, typename Ratio>
-void invoke_inner(fmt::string_view formatstring, const Item item) {
-  const std::chrono::duration<Item, Ratio> value(item);
-  try {
-#if FMT_FUZZ_FORMAT_TO_STRING
-    std::string message = fmt::format(formatstring, value);
-#else
-    fmt::memory_buffer buf;
-    fmt::format_to(buf, formatstring, value);
-#endif
-  } catch (std::exception& /*e*/) {
-  }
-}
-
-// Item is the underlying type for duration (int, long etc)
-template <typename Item>
-void invoke_outer(const uint8_t* Data, size_t Size, const int scaling) {
-  // always use a fixed location of the data
-  using fmt_fuzzer::Nfixed;
-
-  constexpr auto N = sizeof(Item);
-  static_assert(N <= Nfixed, "fixed size is too small");
-  if (Size <= Nfixed + 1) {
-    return;
-  }
-
-  const Item item = fmt_fuzzer::assignFromBuf<Item>(Data);
-
-  // fast forward
-  Data += Nfixed;
-  Size -= Nfixed;
-
-  // Data is already allocated separately in libFuzzer so reading past
-  // the end will most likely be detected anyway
-  const auto formatstring = fmt::string_view(fmt_fuzzer::as_chars(Data), Size);
-
-  // doit_impl<Item,std::yocto>(buf.data(),item);
-  // doit_impl<Item,std::zepto>(buf.data(),item);
-  switch (scaling) {
-  case 1:
-    invoke_inner<Item, std::atto>(formatstring, item);
-    break;
-  case 2:
-    invoke_inner<Item, std::femto>(formatstring, item);
-    break;
-  case 3:
-    invoke_inner<Item, std::pico>(formatstring, item);
-    break;
-  case 4:
-    invoke_inner<Item, std::nano>(formatstring, item);
-    break;
-  case 5:
-    invoke_inner<Item, std::micro>(formatstring, item);
-    break;
-  case 6:
-    invoke_inner<Item, std::milli>(formatstring, item);
-    break;
-  case 7:
-    invoke_inner<Item, std::centi>(formatstring, item);
-    break;
-  case 8:
-    invoke_inner<Item, std::deci>(formatstring, item);
-    break;
-  case 9:
-    invoke_inner<Item, std::deca>(formatstring, item);
-    break;
-  case 10:
-    invoke_inner<Item, std::kilo>(formatstring, item);
-    break;
-  case 11:
-    invoke_inner<Item, std::mega>(formatstring, item);
-    break;
-  case 12:
-    invoke_inner<Item, std::giga>(formatstring, item);
-    break;
-  case 13:
-    invoke_inner<Item, std::tera>(formatstring, item);
-    break;
-  case 14:
-    invoke_inner<Item, std::peta>(formatstring, item);
-    break;
-  case 15:
-    invoke_inner<Item, std::exa>(formatstring, item);
-  }
-  // doit_impl<Item,std::zeta>(buf.data(),item);
-  // doit_impl<Item,std::yotta>(buf.data(),item);
-}
-
-extern "C" int LLVMFuzzerTestOneInput(const uint8_t* Data, size_t Size) {
-  if (Size <= 4) {
-    return 0;
-  }
-
-  const auto representation = Data[0];
-  const auto scaling = Data[1];
-  Data += 2;
-  Size -= 2;
-
-  switch (representation) {
-  case 1:
-    invoke_outer<char>(Data, Size, scaling);
-    break;
-  case 2:
-    invoke_outer<unsigned char>(Data, Size, scaling);
-    break;
-  case 3:
-    invoke_outer<signed char>(Data, Size, scaling);
-    break;
-  case 4:
-    invoke_outer<short>(Data, Size, scaling);
-    break;
-  case 5:
-    invoke_outer<unsigned short>(Data, Size, scaling);
-    break;
-  case 6:
-    invoke_outer<int>(Data, Size, scaling);
-    break;
-  case 7:
-    invoke_outer<unsigned int>(Data, Size, scaling);
-    break;
-  case 8:
-    invoke_outer<long>(Data, Size, scaling);
-    break;
-  case 9:
-    invoke_outer<unsigned long>(Data, Size, scaling);
-    break;
-  case 10:
-    invoke_outer<float>(Data, Size, scaling);
-    break;
-  case 11:
-    invoke_outer<double>(Data, Size, scaling);
-    break;
-  case 12:
-    invoke_outer<long double>(Data, Size, scaling);
-    break;
-  default:
-    break;
-  }
-
-  return 0;
-}

test/fuzzing/float.cc

@@ -0,0 +1,39 @@
+// A fuzzer for floating-point formatter.
+// For the license information refer to format.h.
+
+#include <fmt/format.h>
+
+#include <cstdint>
+#include <cstdlib>
+#include <limits>
+#include <stdexcept>
+
+#include "fuzzer-common.h"
+
+void check_round_trip(fmt::string_view format_str, double value) {
+  auto buffer = fmt::memory_buffer();
+  fmt::format_to(std::back_inserter(buffer), format_str, value);
+
+  if (std::isnan(value)) {
+    auto nan = std::signbit(value) ? "-nan" : "nan";
+    if (fmt::string_view(buffer.data(), buffer.size()) != nan)
+      throw std::runtime_error("round trip failure");
+    return;
+  }
+
+  buffer.push_back('\0');
+  char* ptr = nullptr;
+  if (std::strtod(buffer.data(), &ptr) != value)
+    throw std::runtime_error("round trip failure");
+  if (ptr + 1 != buffer.end()) throw std::runtime_error("unparsed output");
+}
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
+  if (size <= sizeof(double) || !std::numeric_limits<double>::is_iec559)
+    return 0;
+  check_round_trip("{}", assign_from_buf<double>(data));
+  // A larger than necessary precision is used to trigger the fallback
+  // formatter.
+  check_round_trip("{:.50g}", assign_from_buf<double>(data));
+  return 0;
+}

test/fuzzing/fuzzer-common.h

@@ -0,0 +1,77 @@
+// Copyright (c) 2019, Paul Dreik
+// For the license information refer to format.h.
+
+#ifndef FUZZER_COMMON_H
+#define FUZZER_COMMON_H
+
+#include <fmt/core.h>
+
+#include <cstdint>  // std::uint8_t
+#include <cstring>  // memcpy
+#include <vector>
+
+// One can format to either a string, or a buffer. The latter is faster, but
+// one may be interested in formatting to a string instead to verify it works
+// as intended. To avoid a combinatoric explosion, select this at compile time
+// instead of dynamically from the fuzz data.
+#define FMT_FUZZ_FORMAT_TO_STRING 0
+
+// If {fmt} is given a buffer that is separately allocated, chances that address
+// sanitizer detects out of bound reads is much higher. However, it slows down
+// the fuzzing.
+#define FMT_FUZZ_SEPARATE_ALLOCATION 1
+
+// The size of the largest possible type in use.
+// To let the the fuzzer mutation be efficient at cross pollinating between
+// different types, use a fixed size format. The same bit pattern, interpreted
+// as another type, is likely interesting.
+constexpr auto fixed_size = 16;
+
+// Casts data to a char pointer.
+template <typename T> inline const char* as_chars(const T* data) {
+  return reinterpret_cast<const char*>(data);
+}
+
+// Casts data to a byte pointer.
+template <typename T> inline const std::uint8_t* as_bytes(const T* data) {
+  return reinterpret_cast<const std::uint8_t*>(data);
+}
+
+// Blits bytes from data to form an (assumed trivially constructible) object
+// of type Item.
+template <class Item> inline Item assign_from_buf(const std::uint8_t* data) {
+  auto item = Item();
+  std::memcpy(&item, data, sizeof(Item));
+  return item;
+}
+
+// Reads a boolean value by looking at the first byte from data.
+template <> inline bool assign_from_buf<bool>(const std::uint8_t* data) {
+  return *data != 0;
+}
+
+struct data_to_string {
+#if FMT_FUZZ_SEPARATE_ALLOCATION
+  std::vector<char> buffer;
+
+  data_to_string(const uint8_t* data, size_t size, bool add_terminator = false)
+      : buffer(size + (add_terminator ? 1 : 0)) {
+    if (size) {
+      std::memcpy(buffer.data(), data, size);
+    }
+  }
+
+  fmt::string_view get() const { return {buffer.data(), buffer.size()}; }
+#else
+  fmt::string_view sv;
+
+  data_to_string(const uint8_t* data, size_t size, bool = false)
+      : str(as_chars(data), size) {}
+
+  fmt::string_view get() const { return sv; }
+#endif
+
+  const char* data() const { return get().data(); }
+};
+
+#endif  // FUZZER_COMMON_H

test/fuzzing/fuzzer_common.h

@@ -1,67 +0,0 @@
-#ifndef FUZZER_COMMON_H
-#define FUZZER_COMMON_H
-
-// Copyright (c) 2019, Paul Dreik
-// License: see LICENSE.rst in the fmt root directory
-
-#include <cstdint>      // std::uint8_t
-#include <cstring>      // memcpy
-#include <type_traits>  // trivially copyable
-
-// one can format to either a string, or a buf. buf is faster,
-// but one may be interested in formatting to a string instead to
-// verify it works as intended. to avoid a combinatoric explosion,
-// select this at compile time instead of dynamically from the fuzz data
-#define FMT_FUZZ_FORMAT_TO_STRING 0
-
-// if fmt is given a buffer that is separately allocated,
-// chances that address sanitizer detects out of bound reads is
-// much higher. However, it slows down the fuzzing.
-#define FMT_FUZZ_SEPARATE_ALLOCATION 1
-
-// To let the the fuzzer mutation be efficient at cross pollinating
-// between different types, use a fixed size format.
-// The same bit pattern, interpreted as another type,
-// is likely interesting.
-// For this, we must know the size of the largest possible type in use.
-
-// There are some problems on travis, claiming Nfixed is not a constant
-// expression which seems to be an issue with older versions of libstdc++
-#if _GLIBCXX_RELEASE >= 7
-#  include <algorithm>
-namespace fmt_fuzzer {
-constexpr auto Nfixed = std::max(sizeof(long double), sizeof(std::intmax_t));
-}
-#else
-namespace fmt_fuzzer {
-constexpr auto Nfixed = 16;
-}
-#endif
-
-namespace fmt_fuzzer {
-// view data as a c char pointer.
-template <typename T> inline const char* as_chars(const T* data) {
-  return static_cast<const char*>(static_cast<const void*>(data));
-}
-
-// view data as a byte pointer
-template <typename T> inline const std::uint8_t* as_bytes(const T* data) {
-  return static_cast<const std::uint8_t*>(static_cast<const void*>(data));
-}
-
-// blits bytes from Data to form an (assumed trivially constructible) object
-// of type Item
-template <class Item> inline Item assignFromBuf(const std::uint8_t* Data) {
-  Item item{};
-  std::memcpy(&item, Data, sizeof(Item));
-  return item;
-}
-
-// reads a boolean value by looking at the first byte from Data
-template <> inline bool assignFromBuf<bool>(const std::uint8_t* Data) {
-  return !!Data[0];
-}
-
-}  // namespace fmt_fuzzer
-
-#endif  // FUZZER_COMMON_H

test/fuzzing/main.cc

@@ -0,0 +1,22 @@
+#include <cassert>
+#include <fstream>
+#include <vector>
+
+#include "fuzzer-common.h"
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size);
+
+int main(int argc, char** argv) {
+  for (int i = 1; i < argc; ++i) {
+    std::ifstream in(argv[i]);
+    assert(in);
+    in.seekg(0, std::ios_base::end);
+    const auto size = in.tellg();
+    assert(size >= 0);
+    in.seekg(0, std::ios_base::beg);
+    std::vector<char> buf(static_cast<size_t>(size));
+    in.read(buf.data(), size);
+    assert(in.gcount() == size);
+    LLVMFuzzerTestOneInput(as_bytes(buf.data()), buf.size());
+  }
+}

test/fuzzing/main.cpp

@@ -1,21 +0,0 @@
-#include <cassert>
-#include <fstream>
-#include <sstream>
-#include <vector>
-#include "fuzzer_common.h"
-
-extern "C" int LLVMFuzzerTestOneInput(const uint8_t* Data, size_t Size);
-int main(int argc, char* argv[]) {
-  for (int i = 1; i < argc; ++i) {
-    std::ifstream in(argv[i]);
-    assert(in);
-    in.seekg(0, std::ios_base::end);
-    const auto pos = in.tellg();
-    assert(pos >= 0);
-    in.seekg(0, std::ios_base::beg);
-    std::vector<char> buf(static_cast<size_t>(pos));
-    in.read(buf.data(), static_cast<long>(buf.size()));
-    assert(in.gcount() == pos);
-    LLVMFuzzerTestOneInput(fmt_fuzzer::as_bytes(buf.data()), buf.size());
-  }
-}

test/fuzzing/named-arg.cc

@@ -0,0 +1,102 @@
+// Copyright (c) 2019, Paul Dreik
+// For the license information refer to format.h.
+
+#include <fmt/chrono.h>
+
+#include <cstdint>
+#include <type_traits>
+#include <vector>
+
+#include "fuzzer-common.h"
+
+template <typename T>
+void invoke_fmt(const uint8_t* data, size_t size, unsigned arg_name_size) {
+  static_assert(sizeof(T) <= fixed_size, "fixed_size too small");
+  if (size <= fixed_size) return;
+  const T value = assign_from_buf<T>(data);
+  data += fixed_size;
+  size -= fixed_size;
+
+  if (arg_name_size <= 0 || arg_name_size >= size) return;
+  data_to_string arg_name(data, arg_name_size, true);
+  data += arg_name_size;
+  size -= arg_name_size;
+
+  data_to_string format_str(data, size);
+  try {
+#if FMT_FUZZ_FORMAT_TO_STRING
+    std::string message =
+        fmt::format(format_str.get(), fmt::arg(arg_name.data(), value));
+#else
+    fmt::memory_buffer out;
+    fmt::format_to(std::back_inserter(out), format_str.get(),
+                   fmt::arg(arg_name.data(), value));
+#endif
+  } catch (std::exception&) {
+  }
+}
+
+// For dynamic dispatching to an explicit instantiation.
+template <typename Callback> void invoke(int type, Callback callback) {
+  switch (type) {
+  case 0:
+    callback(bool());
+    break;
+  case 1:
+    callback(char());
+    break;
+  case 2:
+    using sc = signed char;
+    callback(sc());
+    break;
+  case 3:
+    using uc = unsigned char;
+    callback(uc());
+    break;
+  case 4:
+    callback(short());
+    break;
+  case 5:
+    using us = unsigned short;
+    callback(us());
+    break;
+  case 6:
+    callback(int());
+    break;
+  case 7:
+    callback(unsigned());
+    break;
+  case 8:
+    callback(long());
+    break;
+  case 9:
+    using ul = unsigned long;
+    callback(ul());
+    break;
+  case 10:
+    callback(float());
+    break;
+  case 11:
+    callback(double());
+    break;
+  case 12:
+    using LD = long double;
+    callback(LD());
+    break;
+  }
+}
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
+  if (size <= 3) return 0;
+
+  // Switch types depending on the first byte of the input.
+  const auto type = data[0] & 0x0F;
+  const unsigned arg_name_size = (data[0] & 0xF0) >> 4;
+  data++;
+  size--;
+
+  invoke(type, [=](auto arg) {
+    invoke_fmt<decltype(arg)>(data, size, arg_name_size);
+  });
+  return 0;
+}

test/fuzzing/named_arg.cpp

@@ -1,128 +0,0 @@
-// Copyright (c) 2019, Paul Dreik
-// License: see LICENSE.rst in the fmt root directory
-
-#include <fmt/chrono.h>
-#include <fmt/core.h>
-#include <cstdint>
-#include <stdexcept>
-#include <type_traits>
-#include <vector>
-#include "fuzzer_common.h"
-
-template <typename Item1>
-void invoke_fmt(const uint8_t* Data, size_t Size, unsigned int argsize) {
-  constexpr auto N1 = sizeof(Item1);
-  static_assert(N1 <= fmt_fuzzer::Nfixed, "Nfixed too small");
-  if (Size <= fmt_fuzzer::Nfixed) {
-    return;
-  }
-  const Item1 item1 = fmt_fuzzer::assignFromBuf<Item1>(Data);
-
-  Data += fmt_fuzzer::Nfixed;
-  Size -= fmt_fuzzer::Nfixed;
-
-  // how many chars should be used for the argument name?
-  if (argsize <= 0 || argsize >= Size) {
-    return;
-  }
-
-  // allocating buffers separately is slower, but increases chances
-  // of detecting memory errors
-#if FMT_FUZZ_SEPARATE_ALLOCATION
-  std::vector<char> argnamebuffer(argsize + 1);
-  std::memcpy(argnamebuffer.data(), Data, argsize);
-  auto argname = argnamebuffer.data();
-#else
-  auto argname = fmt_fuzzer::as_chars(Data);
-#endif
-  Data += argsize;
-  Size -= argsize;
-
-#if FMT_FUZZ_SEPARATE_ALLOCATION
-  // allocates as tight as possible, making it easier to catch buffer overruns.
-  std::vector<char> fmtstringbuffer(Size);
-  std::memcpy(fmtstringbuffer.data(), Data, Size);
-  auto fmtstring = fmt::string_view(fmtstringbuffer.data(), Size);
-#else
-  auto fmtstring = fmt::string_view(fmt_fuzzer::as_chars(Data), Size);
-#endif
-
-#if FMT_FUZZ_FORMAT_TO_STRING
-  std::string message = fmt::format(fmtstring, fmt::arg(argname, item1));
-#else
-  fmt::memory_buffer outbuf;
-  fmt::format_to(outbuf, fmtstring, fmt::arg(argname, item1));
-#endif
-}
-
-// for dynamic dispatching to an explicit instantiation
-template <typename Callback> void invoke(int index, Callback callback) {
-  switch (index) {
-  case 0:
-    callback(bool{});
-    break;
-  case 1:
-    callback(char{});
-    break;
-  case 2:
-    using sc = signed char;
-    callback(sc{});
-    break;
-  case 3:
-    using uc = unsigned char;
-    callback(uc{});
-    break;
-  case 4:
-    callback(short{});
-    break;
-  case 5:
-    using us = unsigned short;
-    callback(us{});
-    break;
-  case 6:
-    callback(int{});
-    break;
-  case 7:
-    callback(unsigned{});
-    break;
-  case 8:
-    callback(long{});
-    break;
-  case 9:
-    using ul = unsigned long;
-    callback(ul{});
-    break;
-  case 10:
-    callback(float{});
-    break;
-  case 11:
-    callback(double{});
-    break;
-  case 12:
-    using LD = long double;
-    callback(LD{});
-    break;
-  }
-}
-
-extern "C" int LLVMFuzzerTestOneInput(const uint8_t* Data, size_t Size) {
-  if (Size <= 3) {
-    return 0;
-  }
-
-  // switch types depending on the first byte of the input
-  const auto first = Data[0] & 0x0F;
-  const unsigned int second = (Data[0] & 0xF0) >> 4;
-  Data++;
-  Size--;
-
-  auto outerfcn = [=](auto param1) {
-    invoke_fmt<decltype(param1)>(Data, Size, second);
-  };
-
-  try {
-    invoke(first, outerfcn);
-  } catch (std::exception& /*e*/) {
-  }
-  return 0;
-}

test/fuzzing/one-arg.cc

@@ -0,0 +1,92 @@
+// Copyright (c) 2019, Paul Dreik
+// For the license information refer to format.h.
+
+#include <fmt/chrono.h>
+
+#include <cstdint>
+#include <exception>
+
+#include "fuzzer-common.h"
+
+template <typename T, typename Repr> const T* from_repr(const Repr& r) {
+  return &r;
+}
+
+template <> const std::tm* from_repr<std::tm>(const std::time_t& t) {
+  return std::localtime(&t);
+}
+
+template <typename T, typename Repr = T>
+void invoke_fmt(const uint8_t* data, size_t size) {
+  static_assert(sizeof(Repr) <= fixed_size, "Nfixed is too small");
+  if (size <= fixed_size) return;
+  auto repr = assign_from_buf<Repr>(data);
+  const T* value = from_repr<T>(repr);
+  if (!value) return;
+  data += fixed_size;
+  size -= fixed_size;
+  data_to_string format_str(data, size);
+  try {
+#if FMT_FUZZ_FORMAT_TO_STRING
+    std::string message = fmt::format(format_str.get(), *value);
+#else
+    auto buf = fmt::memory_buffer();
+    fmt::format_to(std::back_inserter(buf), format_str.get(), *value);
+#endif
+  } catch (std::exception&) {
+  }
+}
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
+  if (size <= 3) return 0;
+
+  const auto first = data[0];
+  data++;
+  size--;
+
+  switch (first) {
+  case 0:
+    invoke_fmt<bool>(data, size);
+    break;
+  case 1:
+    invoke_fmt<char>(data, size);
+    break;
+  case 2:
+    invoke_fmt<unsigned char>(data, size);
+    break;
+  case 3:
+    invoke_fmt<signed char>(data, size);
+    break;
+  case 4:
+    invoke_fmt<short>(data, size);
+    break;
+  case 5:
+    invoke_fmt<unsigned short>(data, size);
+    break;
+  case 6:
+    invoke_fmt<int>(data, size);
+    break;
+  case 7:
+    invoke_fmt<unsigned int>(data, size);
+    break;
+  case 8:
+    invoke_fmt<long>(data, size);
+    break;
+  case 9:
+    invoke_fmt<unsigned long>(data, size);
+    break;
+  case 10:
+    invoke_fmt<float>(data, size);
+    break;
+  case 11:
+    invoke_fmt<double>(data, size);
+    break;
+  case 12:
+    invoke_fmt<long double>(data, size);
+    break;
+  case 13:
+    invoke_fmt<std::tm, std::time_t>(data, size);
+    break;
+  }
+  return 0;
+}

test/fuzzing/one_arg.cpp

@@ -1,131 +0,0 @@
-// Copyright (c) 2019, Paul Dreik
-// License: see LICENSE.rst in the fmt root directory
-
-#include <fmt/core.h>
-#include <cstdint>
-#include <stdexcept>
-#include <type_traits>
-#include <vector>
-
-#include <fmt/chrono.h>
-#include "fuzzer_common.h"
-
-using fmt_fuzzer::Nfixed;
-
-template <typename Item>
-void invoke_fmt(const uint8_t* Data, size_t Size) {
-  constexpr auto N = sizeof(Item);
-  static_assert(N <= Nfixed, "Nfixed is too small");
-  if (Size <= Nfixed) {
-    return;
-  }
-  const Item item = fmt_fuzzer::assignFromBuf<Item>(Data);
-  Data += Nfixed;
-  Size -= Nfixed;
-
-#if FMT_FUZZ_SEPARATE_ALLOCATION
-  // allocates as tight as possible, making it easier to catch buffer overruns.
-  std::vector<char> fmtstringbuffer(Size);
-  std::memcpy(fmtstringbuffer.data(), Data, Size);
-  auto fmtstring = fmt::string_view(fmtstringbuffer.data(), Size);
-#else
-  auto fmtstring = fmt::string_view(fmt_fuzzer::as_chars(Data), Size);
-#endif
-
-#if FMT_FUZZ_FORMAT_TO_STRING
-  std::string message = fmt::format(fmtstring, item);
-#else
-  fmt::memory_buffer message;
-  fmt::format_to(message, fmtstring, item);
-#endif
-}
-
-void invoke_fmt_time(const uint8_t* Data, size_t Size) {
-  using Item = std::time_t;
-  constexpr auto N = sizeof(Item);
-  static_assert(N <= Nfixed, "Nfixed too small");
-  if (Size <= Nfixed) {
-    return;
-  }
-  const Item item = fmt_fuzzer::assignFromBuf<Item>(Data);
-  Data += Nfixed;
-  Size -= Nfixed;
-#if FMT_FUZZ_SEPARATE_ALLOCATION
-  // allocates as tight as possible, making it easier to catch buffer overruns.
-  std::vector<char> fmtstringbuffer(Size);
-  std::memcpy(fmtstringbuffer.data(), Data, Size);
-  auto fmtstring = fmt::string_view(fmtstringbuffer.data(), Size);
-#else
-  auto fmtstring = fmt::string_view(fmt_fuzzer::as_chars(Data), Size);
-#endif
-  auto* b = std::localtime(&item);
-  if (b) {
-#if FMT_FUZZ_FORMAT_TO_STRING
-    std::string message = fmt::format(fmtstring, *b);
-#else
-    fmt::memory_buffer message;
-    fmt::format_to(message, fmtstring, *b);
-#endif
-  }
-}
-
-extern "C" int LLVMFuzzerTestOneInput(const uint8_t* Data, size_t Size) {
-  if (Size <= 3) {
-    return 0;
-  }
-
-  const auto first = Data[0];
-  Data++;
-  Size--;
-
-  try {
-    switch (first) {
-    case 0:
-      invoke_fmt<bool>(Data, Size);
-      break;
-    case 1:
-      invoke_fmt<char>(Data, Size);
-      break;
-    case 2:
-      invoke_fmt<unsigned char>(Data, Size);
-      break;
-    case 3:
-      invoke_fmt<signed char>(Data, Size);
-      break;
-    case 4:
-      invoke_fmt<short>(Data, Size);
-      break;
-    case 5:
-      invoke_fmt<unsigned short>(Data, Size);
-      break;
-    case 6:
-      invoke_fmt<int>(Data, Size);
-      break;
-    case 7:
-      invoke_fmt<unsigned int>(Data, Size);
-      break;
-    case 8:
-      invoke_fmt<long>(Data, Size);
-      break;
-    case 9:
-      invoke_fmt<unsigned long>(Data, Size);
-      break;
-    case 10:
-      invoke_fmt<float>(Data, Size);
-      break;
-    case 11:
-      invoke_fmt<double>(Data, Size);
-      break;
-    case 12:
-      invoke_fmt<long double>(Data, Size);
-      break;
-    case 13:
-      invoke_fmt_time(Data, Size);
-      break;
-    default:
-      break;
-    }
-  } catch (std::exception& /*e*/) {
-  }
-  return 0;
-}

test/fuzzing/sprintf.cpp

@@ -1,116 +0,0 @@
-// Copyright (c) 2019, Paul Dreik
-// License: see LICENSE.rst in the fmt root directory
-#include <fmt/format.h>
-#include <fmt/printf.h>
-#include <cstdint>
-#include <stdexcept>
-
-#include "fuzzer_common.h"
-
-using fmt_fuzzer::Nfixed;
-
-template <typename Item1, typename Item2>
-void invoke_fmt(const uint8_t* Data, size_t Size) {
-  constexpr auto N1 = sizeof(Item1);
-  constexpr auto N2 = sizeof(Item2);
-  static_assert(N1 <= Nfixed, "size1 exceeded");
-  static_assert(N2 <= Nfixed, "size2 exceeded");
-  if (Size <= Nfixed + Nfixed) {
-    return;
-  }
-  Item1 item1 = fmt_fuzzer::assignFromBuf<Item1>(Data);
-  Data += Nfixed;
-  Size -= Nfixed;
-
-  Item2 item2 = fmt_fuzzer::assignFromBuf<Item2>(Data);
-  Data += Nfixed;
-  Size -= Nfixed;
-
-  auto fmtstring = fmt::string_view(fmt_fuzzer::as_chars(Data), Size);
-
-#if FMT_FUZZ_FORMAT_TO_STRING
-  std::string message = fmt::format(fmtstring, item1, item2);
-#else
-  fmt::memory_buffer message;
-  fmt::format_to(message, fmtstring, item1, item2);
-#endif
-}
-
-// for dynamic dispatching to an explicit instantiation
-template <typename Callback> void invoke(int index, Callback callback) {
-  switch (index) {
-  case 0:
-    callback(bool{});
-    break;
-  case 1:
-    callback(char{});
-    break;
-  case 2:
-    using sc = signed char;
-    callback(sc{});
-    break;
-  case 3:
-    using uc = unsigned char;
-    callback(uc{});
-    break;
-  case 4:
-    callback(short{});
-    break;
-  case 5:
-    using us = unsigned short;
-    callback(us{});
-    break;
-  case 6:
-    callback(int{});
-    break;
-  case 7:
-    callback(unsigned{});
-    break;
-  case 8:
-    callback(long{});
-    break;
-  case 9:
-    using ul = unsigned long;
-    callback(ul{});
-    break;
-  case 10:
-    callback(float{});
-    break;
-  case 11:
-    callback(double{});
-    break;
-  case 12:
-    using LD = long double;
-    callback(LD{});
-    break;
-  case 13:
-    using ptr = void*;
-    callback(ptr{});
-    break;
-  }
-}
-
-extern "C" int LLVMFuzzerTestOneInput(const uint8_t* Data, size_t Size) {
-  if (Size <= 3) {
-    return 0;
-  }
-
-  // switch types depending on the first byte of the input
-  const auto first = Data[0] & 0x0F;
-  const auto second = (Data[0] & 0xF0) >> 4;
-  Data++;
-  Size--;
-
-  auto outer = [=](auto param1) {
-    auto inner = [=](auto param2) {
-      invoke_fmt<decltype(param1), decltype(param2)>(Data, Size);
-    };
-    invoke(second, inner);
-  };
-
-  try {
-    invoke(first, outer);
-  } catch (std::exception& /*e*/) {
-  }
-  return 0;
-}

test/fuzzing/two-args.cc

@@ -0,0 +1,106 @@
+// Copyright (c) 2019, Paul Dreik
+// For the license information refer to format.h.
+
+#include <fmt/format.h>
+
+#include <cstdint>
+#include <exception>
+#include <string>
+
+#include "fuzzer-common.h"
+
+template <typename Item1, typename Item2>
+void invoke_fmt(const uint8_t* data, size_t size) {
+  static_assert(sizeof(Item1) <= fixed_size, "size1 exceeded");
+  static_assert(sizeof(Item2) <= fixed_size, "size2 exceeded");
+  if (size <= fixed_size + fixed_size) return;
+
+  const Item1 item1 = assign_from_buf<Item1>(data);
+  data += fixed_size;
+  size -= fixed_size;
+
+  const Item2 item2 = assign_from_buf<Item2>(data);
+  data += fixed_size;
+  size -= fixed_size;
+
+  auto format_str = fmt::string_view(as_chars(data), size);
+#if FMT_FUZZ_FORMAT_TO_STRING
+  std::string message = fmt::format(format_str, item1, item2);
+#else
+  auto buf = fmt::memory_buffer();
+  fmt::format_to(std::back_inserter(buf), format_str, item1, item2);
+#endif
+}
+
+// For dynamic dispatching to an explicit instantiation.
+template <typename Callback> void invoke(int index, Callback callback) {
+  switch (index) {
+  case 0:
+    callback(bool());
+    break;
+  case 1:
+    callback(char());
+    break;
+  case 2:
+    using sc = signed char;
+    callback(sc());
+    break;
+  case 3:
+    using uc = unsigned char;
+    callback(uc());
+    break;
+  case 4:
+    callback(short());
+    break;
+  case 5:
+    using us = unsigned short;
+    callback(us());
+    break;
+  case 6:
+    callback(int());
+    break;
+  case 7:
+    callback(unsigned());
+    break;
+  case 8:
+    callback(long());
+    break;
+  case 9:
+    using ul = unsigned long;
+    callback(ul());
+    break;
+  case 10:
+    callback(float());
+    break;
+  case 11:
+    callback(double());
+    break;
+  case 12:
+    using LD = long double;
+    callback(LD());
+    break;
+  case 13:
+    using ptr = void*;
+    callback(ptr());
+    break;
+  }
+}
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
+  if (size <= 3) return 0;
+
+  // Switch types depending on the first byte of the input.
+  const auto type1 = data[0] & 0x0F;
+  const auto type2 = (data[0] & 0xF0) >> 4;
+  data++;
+  size--;
+  try {
+    invoke(type1, [=](auto param1) {
+      invoke(type2, [=](auto param2) {
+        invoke_fmt<decltype(param1), decltype(param2)>(data, size);
+      });
+    });
+  } catch (std::exception&) {
+  }
+  return 0;
+}

test/fuzzing/two_args.cpp

@@ -1,112 +0,0 @@
-// Copyright (c) 2019, Paul Dreik
-// License: see LICENSE.rst in the fmt root directory
-#include <fmt/format.h>
-#include <cstdint>
-#include <stdexcept>
-#include <type_traits>
-
-#include "fuzzer_common.h"
-
-constexpr auto Nfixed = fmt_fuzzer::Nfixed;
-
-template <typename Item1, typename Item2>
-void invoke_fmt(const uint8_t* Data, size_t Size) {
-  constexpr auto N1 = sizeof(Item1);
-  constexpr auto N2 = sizeof(Item2);
-  static_assert(N1 <= Nfixed, "size1 exceeded");
-  static_assert(N2 <= Nfixed, "size2 exceeded");
-  if (Size <= Nfixed + Nfixed) {
-    return;
-  }
-  const Item1 item1 = fmt_fuzzer::assignFromBuf<Item1>(Data);
-  Data += Nfixed;
-  Size -= Nfixed;
-
-  const Item2 item2 = fmt_fuzzer::assignFromBuf<Item2>(Data);
-  Data += Nfixed;
-  Size -= Nfixed;
-
-  auto fmtstring = fmt::string_view(fmt_fuzzer::as_chars(Data), Size);
-
-#if FMT_FUZZ_FORMAT_TO_STRING
-  std::string message = fmt::format(fmtstring, item1, item2);
-#else
-  fmt::memory_buffer message;
-  fmt::format_to(message, fmtstring, item1, item2);
-#endif
-}
-
-// for dynamic dispatching to an explicit instantiation
-template <typename Callback> void invoke(int index, Callback callback) {
-  switch (index) {
-  case 0:
-    callback(bool{});
-    break;
-  case 1:
-    callback(char{});
-    break;
-  case 2:
-    using sc = signed char;
-    callback(sc{});
-    break;
-  case 3:
-    using uc = unsigned char;
-    callback(uc{});
-    break;
-  case 4:
-    callback(short{});
-    break;
-  case 5:
-    using us = unsigned short;
-    callback(us{});
-    break;
-  case 6:
-    callback(int{});
-    break;
-  case 7:
-    callback(unsigned{});
-    break;
-  case 8:
-    callback(long{});
-    break;
-  case 9:
-    using ul = unsigned long;
-    callback(ul{});
-    break;
-  case 10:
-    callback(float{});
-    break;
-  case 11:
-    callback(double{});
-    break;
-  case 12:
-    using LD = long double;
-    callback(LD{});
-    break;
-  }
-}
-
-extern "C" int LLVMFuzzerTestOneInput(const uint8_t* Data, size_t Size) {
-  if (Size <= 3) {
-    return 0;
-  }
-
-  // switch types depending on the first byte of the input
-  const auto first = Data[0] & 0x0F;
-  const auto second = (Data[0] & 0xF0) >> 4;
-  Data++;
-  Size--;
-
-  auto outer = [=](auto param1) {
-    auto inner = [=](auto param2) {
-      invoke_fmt<decltype(param1), decltype(param2)>(Data, Size);
-    };
-    invoke(second, inner);
-  };
-
-  try {
-    invoke(first, outer);
-  } catch (std::exception& /*e*/) {
-  }
-  return 0;
-}