Update version

Fixes #1747

.gitignore

@@ -1,4 +1,5 @@
 .vscode/
+.vs/
 
 *.iml
 .idea/
@@ -14,6 +15,7 @@ bin/
 /CMakeScripts
 /doc/doxyxml
 /doc/html
+/doc/node_modules
 virtualenv
 /Testing
 /install_manifest.txt

.travis.yml

@@ -92,45 +92,6 @@ matrix:
       # g++ 4.8 on Linux with C++11
     - env: COMPILER=g++-4.8 BUILD=Debug STANDARD=11
       compiler: gcc
-    - name: Android NDK (Gradle)
-      language: android
-      addons:
-        apt:
-          update: true
-          sources:
-            - ubuntu-toolchain-r-test
-          packages:
-            - ninja-build
-            - curl
-            - tree
-      android:
-        components:
-          - tools
-          - platform-tools
-          - android-25 # 7.0
-          - android-27 # 8.1
-          - android-28 # 9.0
-          - build-tools-28.0.3
-      before_install:
-        # Install Gradle from https://sdkman.io/
-        - curl -s "https://get.sdkman.io" | bash > /dev/null
-        - source "$HOME/.sdkman/bin/sdkman-init.sh"
-        - sdk version
-        - sdk install gradle
-        - sdk use gradle
-        - gradle --version
-      install:
-        # Accept SDK Licenses + Install NDK
-        - yes | sdkmanager --update > /dev/null 2>&1
-        - sdkmanager ndk-bundle > /dev/null 2>&1
-      before_script:
-        - pushd ./support
-      script:
-        - gradle clean
-        - gradle assemble
-      after_success:
-        - popd;
-        - tree ./libs
 
 before_script:
   - if [[ "${TRAVIS_OS_NAME}" == "linux" ]]; then export CXX=${COMPILER}; fi

CMakeLists.txt

@@ -24,15 +24,32 @@ function(join result_var)
   set(${result_var} "${result}" PARENT_SCOPE)
 endfunction()
 
+# Sets a cache variable with a docstring joined from multiple arguments:
+#   set(<variable> <value>... CACHE <type> <docstring>...)
+# This allows splitting a long docstring for readability.
+function(set_verbose)
+  cmake_parse_arguments(SET_VERBOSE "" "" "CACHE" ${ARGN})
+  list(GET SET_VERBOSE_CACHE 0 type)
+  list(REMOVE_AT SET_VERBOSE_CACHE 0)
+  join(doc ${SET_VERBOSE_CACHE})
+  set(${SET_VERBOSE_UNPARSED_ARGUMENTS} CACHE ${type} ${doc})
+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)
-  join(doc "Choose the type of build, options are: None(CMAKE_CXX_FLAGS or "
-           "CMAKE_C_FLAGS used) Debug Release RelWithDebInfo MinSizeRel.")
-  set(CMAKE_BUILD_TYPE Release CACHE STRING ${doc})
+  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.")
 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.")
+
 option(FMT_PEDANTIC "Enable extra warnings and expensive tests." OFF)
 option(FMT_WERROR "Halt the compilation with an error on compiler warnings."
        OFF)
@@ -42,8 +59,8 @@ 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_FUZZ "Generate the fuzz target." OFF)
-
-project(FMT CXX)
+option(FMT_CUDA_TEST "Generate the cuda-test target." OFF)
+option(FMT_OS "Include core requiring OS (Windows/Posix) " ON)
 
 # Get version from core.h
 file(READ include/fmt/core.h core_h)
@@ -60,15 +77,24 @@ message(STATUS "Version: ${FMT_VERSION}")
 
 message(STATUS "Build type: ${CMAKE_BUILD_TYPE}")
 
-set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/bin)
+if (NOT CMAKE_RUNTIME_OUTPUT_DIRECTORY)
+  set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/bin)
+endif ()
 
 set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH}
   "${CMAKE_CURRENT_SOURCE_DIR}/support/cmake")
 
 include(cxx14)
 include(CheckCXXCompilerFlag)
+include(JoinPaths)
 
-set(FMT_REQUIRED_FEATURES cxx_auto_type cxx_variadic_templates)
+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)
+endif ()
+message(STATUS "Required features: ${FMT_REQUIRED_FEATURES}")
 
 if (CMAKE_CXX_COMPILER_ID MATCHES "GNU")
   set(PEDANTIC_COMPILE_FLAGS -pedantic-errors -Wall -Wextra -pedantic
@@ -78,7 +104,7 @@ if (CMAKE_CXX_COMPILER_ID MATCHES "GNU")
       -Wcast-align -Wnon-virtual-dtor
       -Wctor-dtor-privacy -Wdisabled-optimization
       -Winvalid-pch -Woverloaded-virtual
-      -Wconversion
+      -Wconversion -Wswitch-enum
       -Wno-ctor-dtor-privacy -Wno-format-nonliteral -Wno-shadow)
   if (NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS 4.6)
       set(PEDANTIC_COMPILE_FLAGS ${PEDANTIC_COMPILE_FLAGS} -Wnoexcept
@@ -98,7 +124,7 @@ endif ()
 
 if (CMAKE_CXX_COMPILER_ID MATCHES "Clang")
   set(PEDANTIC_COMPILE_FLAGS -Wall -Wextra -pedantic -Wconversion
-      -Wno-sign-conversion)
+      -Wno-sign-conversion -Wdeprecated -Wweak-vtables)
   check_cxx_compiler_flag(-Wzero-as-null-pointer-constant HAS_NULLPTR_WARNING)
   if (HAS_NULLPTR_WARNING)
     set(PEDANTIC_COMPILE_FLAGS ${PEDANTIC_COMPILE_FLAGS}
@@ -122,7 +148,9 @@ if (MASTER_PROJECT AND CMAKE_GENERATOR MATCHES "Visual Studio")
     set(MSBUILD_SETUP "call \"${WINSDK_SETENV}\"")
   endif ()
   # Set FrameworkPathOverride to get rid of MSB3644 warnings.
-  set(netfxpath "C:\\Program Files\\Reference Assemblies\\Microsoft\\Framework\\.NETFramework\\v4.0")
+  join(netfxpath
+       "C:\\Program Files\\Reference Assemblies\\Microsoft\\Framework\\"
+       ".NETFramework\\v4.0")
   file(WRITE run-msbuild.bat "
     ${MSBUILD_SETUP}
     ${CMAKE_MAKE_PROGRAM} -p:FrameworkPathOverride=\"${netfxpath}\" %*")
@@ -135,10 +163,8 @@ endif ()
 
 include(CheckSymbolExists)
 if (WIN32)
-  check_symbol_exists(open io.h HAVE_OPEN)
   check_symbol_exists(_strtod_l "${strtod_l_headers}" HAVE_STRTOD_L)
 else ()
-  check_symbol_exists(open fcntl.h HAVE_OPEN)
   check_symbol_exists(strtod_l "${strtod_l_headers}" HAVE_STRTOD_L)
 endif ()
 
@@ -152,12 +178,11 @@ 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 ostream.h printf.h ranges.h
-                        safe-duration-cast.h)
-set(FMT_SOURCES src/format.cc)
-if (HAVE_OPEN)
-  add_headers(FMT_HEADERS posix.h)
-  set(FMT_SOURCES ${FMT_SOURCES} src/posix.cc)
+                        locale.h os.h ostream.h posix.h printf.h ranges.h)
+if (FMT_OS)
+  set(FMT_SOURCES src/format.cc src/os.cc)
+else()
+  set(FMT_SOURCES src/format.cc)
 endif ()
 
 add_library(fmt ${FMT_SOURCES} ${FMT_HEADERS} README.rst ChangeLog.rst)
@@ -167,6 +192,10 @@ if (HAVE_STRTOD_L)
   target_compile_definitions(fmt PUBLIC FMT_LOCALE)
 endif ()
 
+if (MINGW)
+  target_compile_options(fmt PUBLIC "-Wa,-mbig-obj")
+endif ()
+
 if (FMT_WERROR)
   target_compile_options(fmt PRIVATE ${WERROR_FLAG})
 endif ()
@@ -178,14 +207,23 @@ target_compile_features(fmt INTERFACE ${FMT_REQUIRED_FEATURES})
 
 target_include_directories(fmt PUBLIC
   $<BUILD_INTERFACE:${PROJECT_SOURCE_DIR}/include>
-  $<INSTALL_INTERFACE:include>)
+  $<INSTALL_INTERFACE:${FMT_INC_DIR}>)
+
+set(FMT_DEBUG_POSTFIX d CACHE STRING "Debug library postfix.")
 
 set_target_properties(fmt PROPERTIES
   VERSION ${FMT_VERSION} SOVERSION ${CPACK_PACKAGE_VERSION_MAJOR}
-  DEBUG_POSTFIX d)
+  DEBUG_POSTFIX "${FMT_DEBUG_POSTFIX}")
+
+# Set FMT_LIB_NAME for pkg-config fmt.pc. We cannot use the OUTPUT_NAME target
+# property because it's not set by default.
+set(FMT_LIB_NAME fmt)
+if (CMAKE_BUILD_TYPE STREQUAL "Debug")
+  set(FMT_LIB_NAME ${FMT_LIB_NAME}${FMT_DEBUG_POSTFIX})
+endif ()
 
 if (BUILD_SHARED_LIBS)
-  if (UNIX AND NOT APPLE AND NOT ${CMAKE_SYSTEM_NAME} MATCHES "SunOS")
+  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)
@@ -200,43 +238,40 @@ 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_include_directories(fmt-header-only INTERFACE
   $<BUILD_INTERFACE:${PROJECT_SOURCE_DIR}/include>
-  $<INSTALL_INTERFACE:include>)
+  $<INSTALL_INTERFACE:${FMT_INC_DIR}>)
 
 # Install targets.
 if (FMT_INSTALL)
-  include(GNUInstallDirs)
   include(CMakePackageConfigHelpers)
-  set(FMT_CMAKE_DIR ${CMAKE_INSTALL_LIBDIR}/cmake/fmt CACHE STRING
-      "Installation directory for cmake files, relative to ${CMAKE_INSTALL_PREFIX}.")
+  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.")
   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 (INSTALL_TARGETS fmt)
-  if (TARGET fmt-header-only)
-    set(INSTALL_TARGETS ${INSTALL_TARGETS} fmt-header-only)
-  endif ()
+  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.")
 
-  set(FMT_LIB_DIR ${CMAKE_INSTALL_LIBDIR} CACHE STRING
-      "Installation directory for libraries, relative to ${CMAKE_INSTALL_PREFIX}.")
-
-  set(FMT_INC_DIR ${CMAKE_INSTALL_INCLUDEDIR}/fmt CACHE STRING
-      "Installation directory for include files, relative to ${CMAKE_INSTALL_PREFIX}.")
-
-  set(FMT_PKGCONFIG_DIR ${CMAKE_INSTALL_LIBDIR}/pkgconfig CACHE PATH
-      "Installation directory for pkgconfig (.pc) files, relative to ${CMAKE_INSTALL_PREFIX}.")
+  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.")
 
   # Generate the version, config and target files into the build directory.
   write_basic_package_version_file(
     ${version_config}
     VERSION ${FMT_VERSION}
     COMPATIBILITY AnyNewerVersion)
+
+  join_paths(libdir_for_pc_file "\${exec_prefix}" "${FMT_LIB_DIR}")
+  join_paths(includedir_for_pc_file "\${prefix}" "${FMT_INC_DIR}")
+
   configure_file(
     "${PROJECT_SOURCE_DIR}/support/cmake/fmt.pc.in"
     "${pkgconfig}"
@@ -245,6 +280,8 @@ if (FMT_INSTALL)
     ${PROJECT_SOURCE_DIR}/support/cmake/fmt-config.cmake.in
     ${project_config}
     INSTALL_DESTINATION ${FMT_CMAKE_DIR})
+
+  set(INSTALL_TARGETS fmt fmt-header-only)
   # Use a namespace because CMake provides better diagnostics for namespaced
   # imported targets.
   export(TARGETS ${INSTALL_TARGETS} NAMESPACE fmt::
@@ -259,11 +296,13 @@ if (FMT_INSTALL)
 
   # Install the library and headers.
   install(TARGETS ${INSTALL_TARGETS} EXPORT ${targets_export_name}
-          DESTINATION ${FMT_LIB_DIR})
+          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})
+  install(FILES ${FMT_HEADERS} DESTINATION "${FMT_INC_DIR}/fmt")
   install(FILES "${pkgconfig}" DESTINATION "${FMT_PKGCONFIG_DIR}")
 endif ()
 
@@ -279,13 +318,14 @@ endif ()
 # Control fuzzing independent of the unit tests.
 if (FMT_FUZZ)
   add_subdirectory(test/fuzzing)
+  target_compile_definitions(fmt PUBLIC FMT_FUZZ)
 endif ()
 
 set(gitignore ${PROJECT_SOURCE_DIR}/.gitignore)
 if (MASTER_PROJECT AND EXISTS ${gitignore})
   # Get the list of ignored files from .gitignore.
   file (STRINGS ${gitignore} lines)
-  LIST(REMOVE_ITEM lines /doc/html)
+  list(REMOVE_ITEM lines /doc/html)
   foreach (line ${lines})
     string(REPLACE "." "[.]" line "${line}")
     string(REPLACE "*" ".*" line "${line}")

ChangeLog.rst

@@ -1,3 +1,801 @@
+7.0.0 - 2020-07-05
+------------------
+
+* Reduced the library size. For example, on macOS a stripped test binary
+  statically linked with {fmt} `shrank from ~368k to less than 100k
+  <http://www.zverovich.net/2020/05/21/reducing-library-size.html>`_.
+
+* Added a simpler and more efficient `format string compilation API
+  <https://fmt.dev/dev/api.html#compile-api>`_:
+
+  .. code:: c++
+
+     #include <fmt/compile.h>
+
+     // Converts 42 into std::string using the most efficient method and no
+     // runtime format string processing.
+     std::string s = fmt::format(FMT_COMPILE("{}"), 42);
+
+  The old ``fmt::compile`` API is now deprecated.
+
+* Optimized integer formatting: ``format_to`` with format string compilation
+  and a stack-allocated buffer is now `faster than to_chars on both
+  libc++ and libstdc++
+  <http://www.zverovich.net/2020/06/13/fast-int-to-string-revisited.html>`_.
+
+* Optimized handling of small format strings. For example,
+
+  .. code:: c++
+
+      fmt::format("Result: {}: ({},{},{},{})", str1, str2, str3, str4, str5)
+
+  is now ~40% faster (`#1685 <https://github.com/fmtlib/fmt/issues/1685>`_).
+
+* Applied extern templates to improve compile times when using the core API
+  and ``fmt/format.h`` (`#1452 <https://github.com/fmtlib/fmt/issues/1452>`_).
+  For example, on macOS with clang the compile time of a test translation unit
+  dropped from 2.3s to 0.3s with ``-O2`` and from 0.6s to 0.3s with the default
+  settings (``-O0``).
+
+  Before (``-O2``)::
+
+    % time c++ -c test.cc -I include -std=c++17 -O2
+    c++ -c test.cc -I include -std=c++17 -O2  2.22s user 0.08s system 99% cpu 2.311 total
+
+  After (``-O2``)::
+
+    % time c++ -c test.cc -I include -std=c++17 -O2
+    c++ -c test.cc -I include -std=c++17 -O2  0.26s user 0.04s system 98% cpu 0.303 total
+
+  Before (default)::
+
+    % time c++ -c test.cc -I include -std=c++17
+    c++ -c test.cc -I include -std=c++17  0.53s user 0.06s system 98% cpu 0.601 total
+
+  After (default)::
+
+    % time c++ -c test.cc -I include -std=c++17
+    c++ -c test.cc -I include -std=c++17  0.24s user 0.06s system 98% cpu 0.301 total
+
+  It is still recommended to use ``fmt/core.h`` instead of ``fmt/format.h`` but
+  the compile time difference is now smaller. Thanks
+  `@alex3d <https://github.com/alex3d>`_ for the suggestion.
+
+* Named arguments are now stored on stack (no dynamic memory allocations) and
+  the compiled code is more compact and efficient. For example
+
+  .. code:: c++
+
+     #include <fmt/core.h>
+
+     int main() {
+       fmt::print("The answer is {answer}\n", fmt::arg("answer", 42));
+     }
+
+  compiles to just (`godbolt <https://godbolt.org/z/NcfEp_>`__)
+
+  .. code:: asm
+
+      .LC0:
+              .string "answer"
+      .LC1:
+              .string "The answer is {answer}\n"
+      main:
+              sub     rsp, 56
+              mov     edi, OFFSET FLAT:.LC1
+              mov     esi, 23
+              movabs  rdx, 4611686018427387905
+              lea     rax, [rsp+32]
+              lea     rcx, [rsp+16]
+              mov     QWORD PTR [rsp+8], 1
+              mov     QWORD PTR [rsp], rax
+              mov     DWORD PTR [rsp+16], 42
+              mov     QWORD PTR [rsp+32], OFFSET FLAT:.LC0
+              mov     DWORD PTR [rsp+40], 0
+              call    fmt::v6::vprint(fmt::v6::basic_string_view<char>,
+                                      fmt::v6::format_args)
+              xor     eax, eax
+              add     rsp, 56
+              ret
+
+          .L.str.1:
+                  .asciz  "answer"
+
+* Implemented compile-time checks for dynamic width and precision
+  (`#1614 <https://github.com/fmtlib/fmt/issues/1614>`_):
+
+  .. code:: c++
+
+     #include <fmt/format.h>
+
+     int main() {
+       fmt::print(FMT_STRING("{0:{1}}"), 42);
+     }
+
+  now gives a compilation error because argument 1 doesn't exist::
+
+    In file included from test.cc:1:
+    include/fmt/format.h:2726:27: error: constexpr variable 'invalid_format' must be
+    initialized by a constant expression
+      FMT_CONSTEXPR_DECL bool invalid_format =
+                              ^
+    ...
+    include/fmt/core.h:569:26: note: in call to
+    '&checker(s, {}).context_->on_error(&"argument not found"[0])'
+        if (id >= num_args_) on_error("argument not found");
+                            ^
+
+* Added sentinel support to ``fmt::join``
+  (`#1689 <https://github.com/fmtlib/fmt/pull/1689>`_))
+
+  .. code:: c++
+
+    struct zstring_sentinel {};
+    bool operator==(const char* p, zstring_sentinel) { return *p == '\0'; }
+    bool operator!=(const char* p, zstring_sentinel) { return *p != '\0'; }
+
+    struct zstring {
+      const char* p;
+      const char* begin() const { return p; }
+      zstring_sentinel end() const { return {}; }
+    };
+
+    auto s = fmt::format("{}", fmt::join(zstring{"hello"}, "_"));
+    // s == "h_e_l_l_o"
+
+  Thanks `@BRevzin (Barry Revzin) <https://github.com/BRevzin>`_.
+
+* Added support for named args, ``clear`` and ``reserve`` to
+  ``dynamic_format_arg_store``
+  (`#1655 <https://github.com/fmtlib/fmt/issues/1655>`_,
+  `#1663 <https://github.com/fmtlib/fmt/pull/1663>`_,
+  `#1674 <https://github.com/fmtlib/fmt/pull/1674>`_,
+  `#1677 <https://github.com/fmtlib/fmt/pull/1677>`_).
+  Thanks `@vsolontsov-ll (Vladimir Solontsov)
+  <https://github.com/vsolontsov-ll>`_.
+
+* Added support for the ``'c'`` format specifier to integral types for
+  compatibility with ``std::format``
+  (`#1652 <https://github.com/fmtlib/fmt/issues/1652>`_).
+
+* Replaced the ``'n'`` format specifier with ``'L'`` for compatibility with
+  ``std::format`` (`#1624 <https://github.com/fmtlib/fmt/issues/1624>`_).
+  The ``'n'`` specifier can be enabled via the ``FMT_DEPRECATED_N_SPECIFIER``
+  macro.
+
+* The ``'='`` format specifier is now disabled by default for compatibility with
+  ``std::format``. It can be enabled via the ``FMT_DEPRECATED_NUMERIC_ALIGN``
+  macro.
+
+* Removed the following deprecated APIs:
+
+  * ``FMT_STRING_ALIAS`` and ``fmt`` macros - replaced by ``FMT_STRING``
+  * ``fmt::basic_string_view::char_type`` - replaced by
+    ``fmt::basic_string_view::value_type``
+  * ``convert_to_int``
+  * ``format_arg_store::types``
+  * ``*parse_context`` - replaced by ``*format_parse_context``
+  * ``FMT_DEPRECATED_INCLUDE_OS``
+  * ``FMT_DEPRECATED_PERCENT`` - incompatible with ``std::format``
+  * ``*writer`` - replaced by compiled format API
+
+* Renamed the ``internal`` namespace to ``detail``
+  (`#1538 <https://github.com/fmtlib/fmt/issues/1538>`_). The former is still
+  provided as an alias if the ``FMT_USE_INTERNAL`` macro is defined.
+
+* Improved compatibility between ``fmt::printf`` with the standard specs
+  (`#1595 <https://github.com/fmtlib/fmt/issues/1595>`_,
+  `#1682 <https://github.com/fmtlib/fmt/pull/1682>`_,
+  `#1683 <https://github.com/fmtlib/fmt/pull/1683>`_,
+  `#1687 <https://github.com/fmtlib/fmt/pull/1687>`_,
+  `#1699 <https://github.com/fmtlib/fmt/pull/1699>`_).
+  Thanks `@rimathia <https://github.com/rimathia>`_.
+
+* Fixed handling of ``operator<<`` overloads that use ``copyfmt``
+  (`#1666 <https://github.com/fmtlib/fmt/issues/1666>`_).
+
+* Added the ``FMT_OS`` CMake option to control inclusion of OS-specific APIs
+  in the fmt target. This can be useful for embedded platforms
+  (`#1654 <https://github.com/fmtlib/fmt/issues/1654>`_,
+  `#1656 <https://github.com/fmtlib/fmt/pull/1656>`_).
+  Thanks `@kwesolowski (Krzysztof Wesolowski)
+  <https://github.com/kwesolowski>`_.
+
+* Replaced ``FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION`` with the ``FMT_FUZZ``
+  macro to prevent interferring with fuzzing of projects using {fmt}
+  (`#1650 <https://github.com/fmtlib/fmt/pull/1650>`_).
+  Thanks `@asraa (Asra Ali) <https://github.com/asraa>`_.
+
+* Fixed compatibility with emscripten
+  (`#1636 <https://github.com/fmtlib/fmt/issues/1636>`_,
+  `#1637 <https://github.com/fmtlib/fmt/pull/1637>`_).
+  Thanks `@ArthurSonzogni (Arthur Sonzogni)
+  <https://github.com/ArthurSonzogni>`_.
+
+* Improved documentation
+  (`#704 <https://github.com/fmtlib/fmt/issues/704>`_,
+  `#1643 <https://github.com/fmtlib/fmt/pull/1643>`_,
+  `#1660 <https://github.com/fmtlib/fmt/pull/1660>`_,
+  `#1681 <https://github.com/fmtlib/fmt/pull/1681>`_,
+  `#1691 <https://github.com/fmtlib/fmt/pull/1691>`_,
+  `#1706 <https://github.com/fmtlib/fmt/pull/1706>`_,
+  `#1714 <https://github.com/fmtlib/fmt/pull/1714>`_,
+  `#1721 <https://github.com/fmtlib/fmt/pull/1721>`_,
+  `#1739 <https://github.com/fmtlib/fmt/pull/1739>`_,
+  `#1740 <https://github.com/fmtlib/fmt/pull/1740>`_,
+  `#1741 <https://github.com/fmtlib/fmt/pull/1741>`_,
+  `#1751 <https://github.com/fmtlib/fmt/pull/1751>`_).
+  Thanks `@senior7515 (Alexander Gallego) <https://github.com/senior7515>`_,
+  `@lsr0 (Lindsay Roberts) <https://github.com/lsr0>`_,
+  `@puetzk (Kevin Puetz) <https://github.com/puetzk>`_,
+  `@fpelliccioni (Fernando Pelliccioni) <https://github.com/fpelliccioni>`_,
+  Alexey Kuzmenko, `@jelly (jelle van der Waa) <https://github.com/jelly>`_,
+  `@claremacrae (Clare Macrae) <https://github.com/claremacrae>`_,
+  `@jiapengwen (文佳鹏) <https://github.com/jiapengwen>`_,
+  `@gsjaardema (Greg Sjaardema) <https://github.com/gsjaardema>`_,
+  `@alexey-milovidov <https://github.com/alexey-milovidov>`_.
+
+* Implemented various build configuration fixes and improvements
+  (`#1603 <https://github.com/fmtlib/fmt/pull/1603>`_,
+  `#1657 <https://github.com/fmtlib/fmt/pull/1657>`_,
+  `#1702 <https://github.com/fmtlib/fmt/pull/1702>`_,
+  `#1728 <https://github.com/fmtlib/fmt/pull/1728>`_).
+  Thanks `@scramsby (Scott Ramsby) <https://github.com/scramsby>`_,
+  `@jtojnar (Jan Tojnar) <https://github.com/jtojnar>`_,
+  `@orivej (Orivej Desh) <https://github.com/orivej>`_,
+  `@flagarde <https://github.com/flagarde>`_.
+
+* Fixed various warnings and compilation issues
+  (`#1616 <https://github.com/fmtlib/fmt/pull/1616>`_,
+  `#1620 <https://github.com/fmtlib/fmt/issues/1620>`_,
+  `#1622 <https://github.com/fmtlib/fmt/issues/1622>`_,
+  `#1625 <https://github.com/fmtlib/fmt/issues/1625>`_,
+  `#1627 <https://github.com/fmtlib/fmt/pull/1627>`_,
+  `#1628 <https://github.com/fmtlib/fmt/issues/1628>`_,
+  `#1629 <https://github.com/fmtlib/fmt/pull/1629>`_,
+  `#1631 <https://github.com/fmtlib/fmt/issues/1631>`_,
+  `#1633 <https://github.com/fmtlib/fmt/pull/1633>`_,
+  `#1649 <https://github.com/fmtlib/fmt/pull/1649>`_,
+  `#1658 <https://github.com/fmtlib/fmt/issues/1658>`_,
+  `#1661 <https://github.com/fmtlib/fmt/pull/1661>`_,
+  `#1667 <https://github.com/fmtlib/fmt/pull/1667>`_,
+  `#1668 <https://github.com/fmtlib/fmt/issues/1668>`_,
+  `#1669 <https://github.com/fmtlib/fmt/pull/1669>`_,
+  `#1692 <https://github.com/fmtlib/fmt/issues/1692>`_,
+  `#1696 <https://github.com/fmtlib/fmt/pull/1696>`_,
+  `#1697 <https://github.com/fmtlib/fmt/pull/1697>`_,
+  `#1707 <https://github.com/fmtlib/fmt/issues/1707>`_,
+  `#1712 <https://github.com/fmtlib/fmt/pull/1712>`_,
+  `#1716 <https://github.com/fmtlib/fmt/pull/1716>`_,
+  `#1722 <https://github.com/fmtlib/fmt/pull/1722>`_,
+  `#1724 <https://github.com/fmtlib/fmt/issues/1724>`_,
+  `#1729 <https://github.com/fmtlib/fmt/pull/1729>`_,
+  `#1738 <https://github.com/fmtlib/fmt/pull/1738>`_,
+  `#1742 <https://github.com/fmtlib/fmt/issues/1742>`_,
+  `#1743 <https://github.com/fmtlib/fmt/issues/1743>`_,
+  `#1744 <https://github.com/fmtlib/fmt/pull/1744>`_,
+  `#1747 <https://github.com/fmtlib/fmt/issues/1747>`_,
+  `#1750 <https://github.com/fmtlib/fmt/pull/1750>`_).
+  Thanks `@gsjaardema (Greg Sjaardema) <https://github.com/gsjaardema>`_,
+  `@gabime (Gabi Melman) <https://github.com/gabime>`_,
+  `@johnor (Johan) <https://github.com/johnor>`_,
+  `@gabime (Dmitry Kurkin) <https://github.com/Kurkin>`_,
+  `@invexed (James Beach) <https://github.com/invexed>`_,
+  `@peterbell10 <https://github.com/peterbell10>`_,
+  `@daixtrose (Markus Werle) <https://github.com/daixtrose>`_,
+  `@petrutlucian94 (Lucian Petrut) <https://github.com/petrutlucian94>`_,
+  `@Neargye (Daniil Goncharov) <https://github.com/Neargye>`_,
+  `@ambitslix (Attila M. Szilagyi) <https://github.com/ambitslix>`_,
+  `@gabime (Gabi Melman) <https://github.com/gabime>`_,
+  `@erthink (Leonid Yuriev) <https://github.com/erthink>`_,
+  `@tohammer (Tobias Hammer) <https://github.com/tohammer>`_,
+  `@0x8000-0000 (Florin Iucha) <https://github.com/0x8000-0000>`_.
+
+6.2.1 - 2020-05-09
+------------------
+
+* Fixed ostream support in ``sprintf``
+  (`#1631 <https://github.com/fmtlib/fmt/issues/1631>`_).
+
+* Fixed type detection when using implicit conversion to ``string_view`` and
+  ostream ``operator<<`` inconsistently
+  (`#1662 <https://github.com/fmtlib/fmt/issues/1662>`_).
+
+6.2.0 - 2020-04-05
+------------------
+
+* Improved error reporting when trying to format an object of a non-formattable
+  type:
+
+  .. code:: c++
+
+     fmt::format("{}", S());
+
+  now gives::
+
+    include/fmt/core.h:1015:5: error: static_assert failed due to requirement
+    'formattable' "Cannot format argument. To make type T formattable provide a
+    formatter<T> specialization:
+    https://fmt.dev/latest/api.html#formatting-user-defined-types"
+        static_assert(
+        ^
+    ...
+    note: in instantiation of function template specialization
+    'fmt::v6::format<char [3], S, char>' requested here
+      fmt::format("{}", S());
+           ^
+
+  if ``S`` is not formattable.
+
+* Reduced the library size by ~10%.
+
+* Always print decimal point if ``#`` is specified
+  (`#1476 <https://github.com/fmtlib/fmt/issues/1476>`_,
+  `#1498 <https://github.com/fmtlib/fmt/issues/1498>`_):
+
+  .. code:: c++
+
+     fmt::print("{:#.0f}", 42.0);
+
+  now prints ``42.``
+
+* Implemented the ``'L'`` specifier for locale-specific numeric formatting to
+  improve compatibility with ``std::format``. The ``'n'`` specifier is now
+  deprecated and will be removed in the next major release.
+
+* Moved OS-specific APIs such as ``windows_error`` from ``fmt/format.h`` to
+  ``fmt/os.h``. You can define ``FMT_DEPRECATED_INCLUDE_OS`` to automatically
+  include ``fmt/os.h`` from ``fmt/format.h`` for compatibility but this will be
+  disabled in the next major release.
+
+* Added precision overflow detection in floating-point formatting.
+
+* Implemented detection of invalid use of ``fmt::arg``.
+
+* Used ``type_identity`` to block unnecessary template argument deduction.
+  Thanks Tim Song.
+
+* Improved UTF-8 handling
+  (`#1109 <https://github.com/fmtlib/fmt/issues/1109>`_):
+
+  .. code:: c++
+
+     fmt::print("┌{0:─^{2}}┐\n"
+                "│{1: ^{2}}│\n"
+                "└{0:─^{2}}┘\n", "", "Привет, мир!", 20);
+
+  now prints::
+
+     ┌────────────────────┐
+     │    Привет, мир!    │
+     └────────────────────┘
+
+  on systems that support Unicode.
+
+* Added experimental dynamic argument storage
+  (`#1170 <https://github.com/fmtlib/fmt/issues/1170>`_,
+  `#1584 <https://github.com/fmtlib/fmt/pull/1584>`_):
+
+  .. code:: c++
+
+     fmt::dynamic_format_arg_store<fmt::format_context> store;
+     store.push_back("answer");
+     store.push_back(42);
+     fmt::vprint("The {} is {}.\n", store);
+  
+  prints::
+
+     The answer is 42.
+
+  Thanks `@vsolontsov-ll (Vladimir Solontsov)
+  <https://github.com/vsolontsov-ll>`_.
+
+* Made ``fmt::join`` accept ``initializer_list``
+  (`#1591 <https://github.com/fmtlib/fmt/pull/1591>`_).
+  Thanks `@Rapotkinnik (Nikolay Rapotkin) <https://github.com/Rapotkinnik>`_.
+
+* Fixed handling of empty tuples
+  (`#1588 <https://github.com/fmtlib/fmt/issues/1588>`_).
+
+* Fixed handling of output iterators in ``format_to_n``
+  (`#1506 <https://github.com/fmtlib/fmt/issues/1506>`_).
+
+* Fixed formatting of ``std::chrono::duration`` types to wide output
+  (`#1533 <https://github.com/fmtlib/fmt/pull/1533>`_).
+  Thanks `@zeffy (pilao) <https://github.com/zeffy>`_.
+
+* Added const ``begin`` and ``end`` overload to buffers
+  (`#1553 <https://github.com/fmtlib/fmt/pull/1553>`_).
+  Thanks `@dominicpoeschko <https://github.com/dominicpoeschko>`_.
+
+* Added the ability to disable floating-point formatting via ``FMT_USE_FLOAT``,
+  ``FMT_USE_DOUBLE`` and ``FMT_USE_LONG_DOUBLE`` macros for extremely
+  memory-constrained embedded system
+  (`#1590 <https://github.com/fmtlib/fmt/pull/1590>`_).
+  Thanks `@albaguirre (Alberto Aguirre) <https://github.com/albaguirre>`_.
+
+* Made ``FMT_STRING`` work with ``constexpr`` ``string_view``
+  (`#1589 <https://github.com/fmtlib/fmt/pull/1589>`_).
+  Thanks `@scramsby (Scott Ramsby) <https://github.com/scramsby>`_.
+
+* Implemented a minor optimization in the format string parser
+  (`#1560 <https://github.com/fmtlib/fmt/pull/1560>`_).
+  Thanks `@IkarusDeveloper <https://github.com/IkarusDeveloper>`_.
+
+* Improved attribute detection
+  (`#1469 <https://github.com/fmtlib/fmt/pull/1469>`_,
+  `#1475 <https://github.com/fmtlib/fmt/pull/1475>`_,
+  `#1576 <https://github.com/fmtlib/fmt/pull/1576>`_).
+  Thanks `@federico-busato (Federico) <https://github.com/federico-busato>`_,
+  `@chronoxor (Ivan Shynkarenka) <https://github.com/chronoxor>`_,
+  `@refnum <https://github.com/refnum>`_.
+
+* Improved documentation
+  (`#1481 <https://github.com/fmtlib/fmt/pull/1481>`_,
+  `#1523 <https://github.com/fmtlib/fmt/pull/1523>`_).
+  Thanks `@JackBoosY (Jack·Boos·Yu) <https://github.com/JackBoosY>`_,
+  `@imba-tjd (谭九鼎) <https://github.com/imba-tjd>`_.
+
+* Fixed symbol visibility on Linux when compiling with ``-fvisibility=hidden``
+  (`#1535 <https://github.com/fmtlib/fmt/pull/1535>`_).
+  Thanks `@milianw (Milian Wolff) <https://github.com/milianw>`_.
+
+* Implemented various build configuration fixes and improvements
+  (`#1264 <https://github.com/fmtlib/fmt/issues/1264>`_,
+  `#1460 <https://github.com/fmtlib/fmt/issues/1460>`_,
+  `#1534 <https://github.com/fmtlib/fmt/pull/1534>`_,
+  `#1536 <https://github.com/fmtlib/fmt/issues/1536>`_,
+  `#1545 <https://github.com/fmtlib/fmt/issues/1545>`_,
+  `#1546 <https://github.com/fmtlib/fmt/pull/1546>`_,
+  `#1566 <https://github.com/fmtlib/fmt/issues/1566>`_,
+  `#1582 <https://github.com/fmtlib/fmt/pull/1582>`_,
+  `#1597 <https://github.com/fmtlib/fmt/issues/1597>`_,
+  `#1598 <https://github.com/fmtlib/fmt/pull/1598>`_).
+  Thanks `@ambitslix (Attila M. Szilagyi) <https://github.com/ambitslix>`_,
+  `@jwillikers (Jordan Williams) <https://github.com/jwillikers>`_,
+  `@stac47 (Laurent Stacul) <https://github.com/stac47>`_.
+
+* Fixed various warnings and compilation issues
+  (`#1433 <https://github.com/fmtlib/fmt/pull/1433>`_,
+  `#1461 <https://github.com/fmtlib/fmt/issues/1461>`_,
+  `#1470 <https://github.com/fmtlib/fmt/pull/1470>`_,
+  `#1480 <https://github.com/fmtlib/fmt/pull/1480>`_,
+  `#1485 <https://github.com/fmtlib/fmt/pull/1485>`_,
+  `#1492 <https://github.com/fmtlib/fmt/pull/1492>`_,
+  `#1493 <https://github.com/fmtlib/fmt/issues/1493>`_,
+  `#1504 <https://github.com/fmtlib/fmt/issues/1504>`_,
+  `#1505 <https://github.com/fmtlib/fmt/pull/1505>`_,
+  `#1512 <https://github.com/fmtlib/fmt/pull/1512>`_,
+  `#1515 <https://github.com/fmtlib/fmt/issues/1515>`_,
+  `#1516 <https://github.com/fmtlib/fmt/pull/1516>`_,
+  `#1518 <https://github.com/fmtlib/fmt/pull/1518>`_,
+  `#1519 <https://github.com/fmtlib/fmt/pull/1519>`_,
+  `#1520 <https://github.com/fmtlib/fmt/pull/1520>`_,
+  `#1521 <https://github.com/fmtlib/fmt/pull/1521>`_,
+  `#1522 <https://github.com/fmtlib/fmt/pull/1522>`_,
+  `#1524 <https://github.com/fmtlib/fmt/issues/1524>`_,
+  `#1530 <https://github.com/fmtlib/fmt/pull/1530>`_,
+  `#1531 <https://github.com/fmtlib/fmt/issues/1531>`_,
+  `#1532 <https://github.com/fmtlib/fmt/pull/1532>`_,
+  `#1539 <https://github.com/fmtlib/fmt/issues/1539>`_,
+  `#1547 <https://github.com/fmtlib/fmt/issues/1547>`_,
+  `#1548 <https://github.com/fmtlib/fmt/issues/1548>`_,
+  `#1554 <https://github.com/fmtlib/fmt/pull/1554>`_,
+  `#1567 <https://github.com/fmtlib/fmt/issues/1567>`_,
+  `#1568 <https://github.com/fmtlib/fmt/pull/1568>`_,
+  `#1569 <https://github.com/fmtlib/fmt/pull/1569>`_,
+  `#1571 <https://github.com/fmtlib/fmt/pull/1571>`_,
+  `#1573 <https://github.com/fmtlib/fmt/pull/1573>`_,
+  `#1575 <https://github.com/fmtlib/fmt/pull/1575>`_,
+  `#1581 <https://github.com/fmtlib/fmt/pull/1581>`_,
+  `#1583 <https://github.com/fmtlib/fmt/issues/1583>`_,
+  `#1586 <https://github.com/fmtlib/fmt/issues/1586>`_,
+  `#1587 <https://github.com/fmtlib/fmt/issues/1587>`_,
+  `#1594 <https://github.com/fmtlib/fmt/issues/1594>`_,
+  `#1596 <https://github.com/fmtlib/fmt/pull/1596>`_,
+  `#1604 <https://github.com/fmtlib/fmt/issues/1604>`_,
+  `#1606 <https://github.com/fmtlib/fmt/pull/1606>`_,
+  `#1607 <https://github.com/fmtlib/fmt/issues/1607>`_,
+  `#1609 <https://github.com/fmtlib/fmt/issues/1609>`_).
+  Thanks `@marti4d (Chris Martin) <https://github.com/marti4d>`_,
+  `@iPherian <https://github.com/iPherian>`_,
+  `@parkertomatoes <https://github.com/parkertomatoes>`_,
+  `@gsjaardema (Greg Sjaardema) <https://github.com/gsjaardema>`_,
+  `@chronoxor (Ivan Shynkarenka) <https://github.com/chronoxor>`_,
+  `@DanielaE (Daniela Engert) <https://github.com/DanielaE>`_,
+  `@torsten48 <https://github.com/torsten48>`_,
+  `@tohammer (Tobias Hammer) <https://github.com/tohammer>`_,
+  `@lefticus (Jason Turner) <https://github.com/lefticus>`_,
+  `@ryusakki (Haise) <https://github.com/ryusakki>`_,
+  `@adnsv (Alex Denisov) <https://github.com/adnsv>`_,
+  `@fghzxm <https://github.com/fghzxm>`_,
+  `@refnum <https://github.com/refnum>`_,
+  `@pramodk (Pramod Kumbhar) <https://github.com/pramodk>`_,
+  `@Spirrwell <https://github.com/Spirrwell>`_,
+  `@scramsby (Scott Ramsby) <https://github.com/scramsby>`_.
+
+6.1.2 - 2019-12-11
+------------------
+
+* Fixed ABI compatibility with ``libfmt.so.6.0.0``
+  (`#1471 <https://github.com/fmtlib/fmt/issues/1471>`_).
+
+* Fixed handling types convertible to ``std::string_view``
+  (`#1451 <https://github.com/fmtlib/fmt/pull/1451>`_).
+  Thanks `@denizevrenci (Deniz Evrenci) <https://github.com/denizevrenci>`_.
+
+* Made CUDA test an opt-in enabled via the ``FMT_CUDA_TEST`` CMake option.
+
+* Fixed sign conversion warnings
+  (`#1440 <https://github.com/fmtlib/fmt/pull/1440>`_).
+  Thanks `@0x8000-0000 (Florin Iucha) <https://github.com/0x8000-0000>`_.
+
+6.1.1 - 2019-12-04
+------------------
+
+* Fixed shared library build on Windows
+  (`#1443 <https://github.com/fmtlib/fmt/pull/1443>`_,
+  `#1445 <https://github.com/fmtlib/fmt/issues/1445>`_,
+  `#1446 <https://github.com/fmtlib/fmt/pull/1446>`_,
+  `#1450 <https://github.com/fmtlib/fmt/issues/1450>`_).
+  Thanks `@egorpugin (Egor Pugin) <https://github.com/egorpugin>`_,
+  `@bbolli (Beat Bolli) <https://github.com/bbolli>`_.
+
+* Added a missing decimal point in exponent notation with trailing zeros.
+
+* Removed deprecated ``format_arg_store::TYPES``.
+
+6.1.0 - 2019-12-01
+------------------
+
+* {fmt} now formats IEEE 754 ``float`` and ``double`` using the shortest decimal
+  representation with correct rounding by default:
+
+  .. code:: c++
+
+     #include <cmath>
+     #include <fmt/core.h>
+
+     int main() {
+       fmt::print("{}", M_PI);
+     }
+
+  prints ``3.141592653589793``.
+
+* Made the fast binary to decimal floating-point formatter the default,
+  simplified it and improved performance. {fmt} is now 15 times faster than
+  libc++'s ``std::ostringstream``, 11 times faster than ``printf`` and 10%
+  faster than double-conversion on `dtoa-benchmark
+  <https://github.com/fmtlib/dtoa-benchmark>`_:
+
+  ==================  =========  =======
+  Function            Time (ns)  Speedup
+  ==================  =========  =======
+  ostringstream        1,346.30    1.00x
+  ostrstream           1,195.74    1.13x
+  sprintf                995.08    1.35x
+  doubleconv              99.10   13.59x
+  fmt                     88.34   15.24x
+  ==================  =========  =======
+
+  .. image:: https://user-images.githubusercontent.com/576385/
+             69767160-cdaca400-112f-11ea-9fc5-347c9f83caad.png
+
+* {fmt} no longer converts ``float`` arguments to ``double``. In particular this
+  improves the default (shortest) representation of floats and makes
+  ``fmt::format`` consistent with ``std::format`` specs
+  (`#1336 <https://github.com/fmtlib/fmt/issues/1336>`_,
+  `#1353 <https://github.com/fmtlib/fmt/issues/1353>`_,
+  `#1360 <https://github.com/fmtlib/fmt/pull/1360>`_,
+  `#1361 <https://github.com/fmtlib/fmt/pull/1361>`_):
+
+  .. code:: c++
+
+     fmt::print("{}", 0.1f);
+
+  prints ``0.1`` instead of ``0.10000000149011612``.
+
+  Thanks `@orivej (Orivej Desh) <https://github.com/orivej>`_.
+
+* Made floating-point formatting output consistent with ``printf``/iostreams
+  (`#1376 <https://github.com/fmtlib/fmt/issues/1376>`_,
+  `#1417 <https://github.com/fmtlib/fmt/issues/1417>`_).
+
+* Added support for 128-bit integers
+  (`#1287 <https://github.com/fmtlib/fmt/pull/1287>`_):
+
+  .. code:: c++
+
+     fmt::print("{}", std::numeric_limits<__int128_t>::max());
+
+  prints ``170141183460469231731687303715884105727``.
+
+  Thanks `@denizevrenci (Deniz Evrenci) <https://github.com/denizevrenci>`_.
+
+* The overload of ``print`` that takes ``text_style`` is now atomic, i.e. the
+  output from different threads doesn't interleave
+  (`#1351 <https://github.com/fmtlib/fmt/pull/1351>`_).
+  Thanks `@tankiJong (Tanki Zhang) <https://github.com/tankiJong>`_.
+
+* Made compile time in the header-only mode ~20% faster by reducing the number
+  of template instantiations. ``wchar_t`` overload of ``vprint`` was moved from
+  ``fmt/core.h`` to ``fmt/format.h``.
+
+* Added an overload of ``fmt::join`` that works with tuples
+  (`#1322 <https://github.com/fmtlib/fmt/issues/1322>`_,
+  `#1330 <https://github.com/fmtlib/fmt/pull/1330>`_):
+
+  .. code:: c++
+
+     #include <tuple>
+     #include <fmt/ranges.h>
+
+     int main() {
+       std::tuple<char, int, float> t{'a', 1, 2.0f};
+       fmt::print("{}", t);
+     }
+
+  prints ``('a', 1, 2.0)``.
+
+  Thanks `@jeremyong (Jeremy Ong) <https://github.com/jeremyong>`_.
+
+* Changed formatting of octal zero with prefix from "00" to "0":
+
+  .. code:: c++
+
+     fmt::print("{:#o}", 0);
+
+  prints ``0``.
+
+* The locale is now passed to ostream insertion (``<<``) operators
+  (`#1406 <https://github.com/fmtlib/fmt/pull/1406>`_):
+
+  .. code:: c++
+
+     #include <fmt/locale.h>
+     #include <fmt/ostream.h>
+
+     struct S {
+       double value;
+     };
+
+     std::ostream& operator<<(std::ostream& os, S s) {
+       return os << s.value;
+     }
+
+     int main() {
+       auto s = fmt::format(std::locale("fr_FR.UTF-8"), "{}", S{0.42});
+       // s == "0,42"
+     }
+
+  Thanks `@dlaugt (Daniel Laügt) <https://github.com/dlaugt>`_.
+
+* Locale-specific number formatting now uses grouping
+  (`#1393 <https://github.com/fmtlib/fmt/issues/1393>`_
+  `#1394 <https://github.com/fmtlib/fmt/pull/1394>`_).
+  Thanks `@skrdaniel <https://github.com/skrdaniel>`_.
+
+* Fixed handling of types with deleted implicit rvalue conversion to
+  ``const char**`` (`#1421 <https://github.com/fmtlib/fmt/issues/1421>`_):
+
+  .. code:: c++
+
+     struct mystring {
+       operator const char*() const&;
+       operator const char*() &;
+       operator const char*() const&& = delete;
+       operator const char*() && = delete;
+     };
+     mystring str;
+     fmt::print("{}", str); // now compiles
+
+* Enums are now mapped to correct underlying types instead of ``int``
+  (`#1286 <https://github.com/fmtlib/fmt/pull/1286>`_).
+  Thanks `@agmt (Egor Seredin) <https://github.com/agmt>`_.
+
+* Enum classes are no longer implicitly converted to ``int``
+  (`#1424 <https://github.com/fmtlib/fmt/issues/1424>`_).
+
+* Added ``basic_format_parse_context`` for consistency with C++20
+  ``std::format`` and deprecated ``basic_parse_context``.
+
+* Fixed handling of UTF-8 in precision
+  (`#1389 <https://github.com/fmtlib/fmt/issues/1389>`_,
+  `#1390 <https://github.com/fmtlib/fmt/pull/1390>`_).
+  Thanks `@tajtiattila (Attila Tajti) <https://github.com/tajtiattila>`_.
+
+* {fmt} can now be installed on Linux, macOS and Windows with
+  `Conda <https://docs.conda.io/en/latest/>`__ using its
+  `conda-forge <https://conda-forge.org>`__
+  `package <https://github.com/conda-forge/fmt-feedstock>`__
+  (`#1410 <https://github.com/fmtlib/fmt/pull/1410>`_)::
+
+    conda install -c conda-forge fmt
+
+  Thanks `@tdegeus (Tom de Geus) <https://github.com/tdegeus>`_.
+
+* Added a CUDA test (`#1285 <https://github.com/fmtlib/fmt/pull/1285>`_,
+  `#1317 <https://github.com/fmtlib/fmt/pull/1317>`_).
+  Thanks `@luncliff (Park DongHa) <https://github.com/luncliff>`_ and
+  `@risa2000 <https://github.com/risa2000>`_.
+
+* Improved documentation (`#1276 <https://github.com/fmtlib/fmt/pull/1276>`_,
+  `#1291 <https://github.com/fmtlib/fmt/issues/1291>`_,
+  `#1296 <https://github.com/fmtlib/fmt/issues/1296>`_,
+  `#1315 <https://github.com/fmtlib/fmt/pull/1315>`_,
+  `#1332 <https://github.com/fmtlib/fmt/pull/1332>`_,
+  `#1337 <https://github.com/fmtlib/fmt/pull/1337>`_,
+  `#1395 <https://github.com/fmtlib/fmt/issues/1395>`_
+  `#1418 <https://github.com/fmtlib/fmt/pull/1418>`_).
+  Thanks
+  `@waywardmonkeys (Bruce Mitchener) <https://github.com/waywardmonkeys>`_,
+  `@pauldreik (Paul Dreik) <https://github.com/pauldreik>`_,
+  `@jackoalan (Jack Andersen) <https://github.com/jackoalan>`_.
+
+* Various code improvements
+  (`#1358 <https://github.com/fmtlib/fmt/pull/1358>`_,
+  `#1407 <https://github.com/fmtlib/fmt/pull/1407>`_).
+  Thanks `@orivej (Orivej Desh) <https://github.com/orivej>`_,
+  `@dpacbach (David P. Sicilia) <https://github.com/dpacbach>`_,
+
+* Fixed compile-time format string checks for user-defined types
+  (`#1292 <https://github.com/fmtlib/fmt/issues/1292>`_).
+
+* Worked around a false positive in ``unsigned-integer-overflow`` sanitizer
+  (`#1377 <https://github.com/fmtlib/fmt/issues/1377>`_).
+
+* Fixed various warnings and compilation issues
+  (`#1273 <https://github.com/fmtlib/fmt/issues/1273>`_,
+  `#1278 <https://github.com/fmtlib/fmt/pull/1278>`_,
+  `#1280 <https://github.com/fmtlib/fmt/pull/1280>`_,
+  `#1281 <https://github.com/fmtlib/fmt/issues/1281>`_,
+  `#1288 <https://github.com/fmtlib/fmt/issues/1288>`_,
+  `#1290 <https://github.com/fmtlib/fmt/pull/1290>`_,
+  `#1301 <https://github.com/fmtlib/fmt/pull/1301>`_,
+  `#1305 <https://github.com/fmtlib/fmt/issues/1305>`_,
+  `#1306 <https://github.com/fmtlib/fmt/issues/1306>`_,
+  `#1309 <https://github.com/fmtlib/fmt/issues/1309>`_,
+  `#1312 <https://github.com/fmtlib/fmt/pull/1312>`_,
+  `#1313 <https://github.com/fmtlib/fmt/issues/1313>`_,
+  `#1316 <https://github.com/fmtlib/fmt/issues/1316>`_,
+  `#1319 <https://github.com/fmtlib/fmt/issues/1319>`_,
+  `#1320 <https://github.com/fmtlib/fmt/pull/1320>`_,
+  `#1326 <https://github.com/fmtlib/fmt/pull/1326>`_,
+  `#1328 <https://github.com/fmtlib/fmt/pull/1328>`_,
+  `#1344 <https://github.com/fmtlib/fmt/issues/1344>`_,
+  `#1345 <https://github.com/fmtlib/fmt/pull/1345>`_,
+  `#1347 <https://github.com/fmtlib/fmt/pull/1347>`_,
+  `#1349 <https://github.com/fmtlib/fmt/pull/1349>`_,
+  `#1354 <https://github.com/fmtlib/fmt/issues/1354>`_,
+  `#1362 <https://github.com/fmtlib/fmt/issues/1362>`_,
+  `#1366 <https://github.com/fmtlib/fmt/issues/1366>`_,
+  `#1364 <https://github.com/fmtlib/fmt/pull/1364>`_,
+  `#1370 <https://github.com/fmtlib/fmt/pull/1370>`_,
+  `#1371 <https://github.com/fmtlib/fmt/pull/1371>`_,
+  `#1385 <https://github.com/fmtlib/fmt/issues/1385>`_,
+  `#1388 <https://github.com/fmtlib/fmt/issues/1388>`_,
+  `#1397 <https://github.com/fmtlib/fmt/pull/1397>`_,
+  `#1414 <https://github.com/fmtlib/fmt/pull/1414>`_,
+  `#1416 <https://github.com/fmtlib/fmt/pull/1416>`_,
+  `#1422 <https://github.com/fmtlib/fmt/issues/1422>`_
+  `#1427 <https://github.com/fmtlib/fmt/pull/1427>`_,
+  `#1431 <https://github.com/fmtlib/fmt/issues/1431>`_,
+  `#1433 <https://github.com/fmtlib/fmt/pull/1433>`_).
+  Thanks `@hhb <https://github.com/hhb>`_,
+  `@gsjaardema (Greg Sjaardema) <https://github.com/gsjaardema>`_,
+  `@gabime (Gabi Melman) <https://github.com/gabime>`_,
+  `@neheb (Rosen Penev) <https://github.com/neheb>`_,
+  `@vedranmiletic (Vedran Miletić) <https://github.com/vedranmiletic>`_,
+  `@dkavolis (Daumantas Kavolis) <https://github.com/dkavolis>`_,
+  `@mwinterb <https://github.com/mwinterb>`_,
+  `@orivej (Orivej Desh) <https://github.com/orivej>`_,
+  `@denizevrenci (Deniz Evrenci) <https://github.com/denizevrenci>`_
+  `@leonklingele <https://github.com/leonklingele>`_,
+  `@chronoxor (Ivan Shynkarenka) <https://github.com/chronoxor>`_,
+  `@kent-tri <https://github.com/kent-tri>`_,
+  `@0x8000-0000 (Florin Iucha) <https://github.com/0x8000-0000>`_,
+  `@marti4d (Chris Martin) <https://github.com/marti4d>`_.
+
 6.0.0 - 2019-08-26
 ------------------
 
@@ -92,16 +890,16 @@
      #include <fmt/compile.h>
 
      auto f = fmt::compile<int>("{}");
-     std::string s = fmt::format(f, 42); // can be called multiple times to format
-                                         // different values
+     std::string s = fmt::format(f, 42); // can be called multiple times to
+                                         // format different values
      // s == "42"
 
   It moves the cost of parsing a format string outside of the format function
   which can be beneficial when identically formatting many objects of the same
   types. Thanks `@stryku (Mateusz Janek) <https://github.com/stryku>`_.
 
-* Added the ``%`` format specifier that formats floating-point values as
-  percentages (`#1060 <https://github.com/fmtlib/fmt/pull/1060>`_,
+* Added experimental ``%`` format specifier that formats floating-point values
+  as percentages (`#1060 <https://github.com/fmtlib/fmt/pull/1060>`_,
   `#1069 <https://github.com/fmtlib/fmt/pull/1069>`_,
   `#1071 <https://github.com/fmtlib/fmt/pull/1071>`_):
 

README.rst

@@ -7,55 +7,61 @@
 .. image:: https://ci.appveyor.com/api/projects/status/ehjkiefde6gucy1v
    :target: https://ci.appveyor.com/project/vitaut/fmt
 
-.. image:: https://img.shields.io/badge/stackoverflow-fmt-blue.svg
-   :alt: Ask questions at StackOverflow with the tag fmt
-   :target: http://stackoverflow.com/questions/tagged/fmt
-
 .. image:: https://oss-fuzz-build-logs.storage.googleapis.com/badges/libfmt.svg
    :alt: fmt is continuously fuzzed att oss-fuzz
-   :target: https://bugs.chromium.org/p/oss-fuzz/issues/list?colspec=ID%20Type%20Component%20Status%20Proj%20Reported%20Owner%20Summary&q=proj%3Dfmt&can=1
+   :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
+
+.. 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.
 
 `Documentation <https://fmt.dev/latest/>`__
 
-Q&A: ask questions on `StackOverflow with the tag fmt <http://stackoverflow.com/questions/tagged/fmt>`_.
+Q&A: ask questions on `StackOverflow with the tag fmt
+<https://stackoverflow.com/questions/tagged/fmt>`_.
 
 Features
 --------
 
-* Replacement-based `format API <https://fmt.dev/dev/api.html>`_ with
-  positional arguments for localization.
+* Simple `format API <https://fmt.dev/dev/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 `str.format <https://docs.python.org/2/library/stdtypes.html#str.format>`_
-  in Python.
+  of Python's
+  `format <https://docs.python.org/3/library/stdtypes.html#str.format>`_
 * Safe `printf implementation
   <https://fmt.dev/latest/api.html#printf-formatting>`_ including
-  the POSIX extension for positional arguments.
-* Implementation of `C++20 std::format <https://fmt.dev/Text%20Formatting.html>`__.
-* Support for user-defined types.
+  the POSIX extension for positional arguments
+* Extensibility: support for user-defined types
 * High performance: faster than common standard library implementations of
-  `printf <http://en.cppreference.com/w/cpp/io/c/fprintf>`_ and
-  iostreams. See `Speed tests`_ and `Fast integer to string conversion in C++
-  <http://zverovich.net/2013/09/07/integer-to-string-conversion-in-cplusplus.html>`_.
+  `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
+  <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`_.
+  ``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.
+  <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
   reported at compile time, automatic memory management prevents buffer overflow
-  errors.
+  errors
 * Ease of use: small self-contained code base, no external dependencies,
   permissive MIT `license
   <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.
+  consistent output across platforms and support for older compilers
 * Clean warning-free codebase even on high warning levels
-  (``-Wall -Wextra -pedantic``).
-* Support for wide strings.
-* Optional header-only configuration enabled with the ``FMT_HEADER_ONLY`` macro.
+  (``-Wall -Wextra -pedantic``)
+* Locale-independence by default
+* Support for wide strings
+* Optional header-only configuration enabled with the ``FMT_HEADER_ONLY`` macro
 
 See the `documentation <https://fmt.dev/latest/>`_ for more details.
 
@@ -66,38 +72,49 @@ Print ``Hello, world!`` to ``stdout``:
 
 .. code:: c++
 
-    fmt::print("Hello, {}!", "world");  // Python-like format string syntax
-    fmt::printf("Hello, %s!", "world"); // printf format string syntax
+    #include <fmt/core.h>
+    
+    int main() {
+      fmt::print("Hello, world!\n");
+    }
 
-Format a string and use positional arguments:
+Format a string:
+
+.. code:: c++
+
+    std::string s = fmt::format("The answer is {}.", 42);
+    // s == "The answer is 42."
+
+Format a string using positional arguments:
 
 .. 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:
+
+.. code:: c++
+
+    #include <fmt/chrono.h>
+
+    int main() {
+      using namespace std::chrono_literals;
+      fmt::print("Elapsed time: {}", 42ms);
+    }
+
+prints "Elapsed time: 42ms".
+
 Check a format string at compile time:
 
 .. code:: c++
 
     // test.cc
-    #define FMT_STRING_ALIAS 1
     #include <fmt/format.h>
-    std::string s = format(fmt("{2}"), 42);
+    std::string s = format(FMT_STRING("{:d}"), "hello");
 
-.. code::
-
-    $ c++ -Iinclude -std=c++14 test.cc
-    ...
-    test.cc:4:17: note: in instantiation of function template specialization 'fmt::v5::format<S, int>' requested here
-    std::string s = format(fmt("{2}"), 42);
-                    ^
-    include/fmt/core.h:778:19: note: non-constexpr function 'on_error' cannot be used in a constant expression
-        ErrorHandler::on_error(message);
-                      ^
-    include/fmt/format.h:2226:16: note: in call to '&checker.context_->on_error(&"argument index out of range"[0])'
-          context_.on_error("argument index out of range");
-                   ^
+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>`_):
@@ -114,7 +131,7 @@ Format objects of user-defined types via a simple `extension API
 
 .. code:: c++
 
-    #include "fmt/format.h"
+    #include <fmt/format.h>
 
     struct date {
       int year, month, day;
@@ -122,11 +139,10 @@ Format objects of user-defined types via a simple `extension API
 
     template <>
     struct fmt::formatter<date> {
-      template <typename ParseContext>
-      constexpr auto parse(ParseContext &ctx) { return ctx.begin(); }
+      constexpr auto parse(format_parse_context& ctx) { return ctx.begin(); }
 
       template <typename FormatContext>
-      auto format(const date &d, FormatContext &ctx) {
+      auto format(const date& d, FormatContext& ctx) {
         return format_to(ctx.out(), "{}-{}-{}", d.year, d.month, d.day);
       }
     };
@@ -142,12 +158,12 @@ 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) {
+    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) {
+    void report_error(const char* format, const Args & ... args) {
       vreport_error(format, fmt::make_format_args(args...));
     }
 
@@ -166,28 +182,27 @@ Speed tests
 ================= ============= ===========
 Library           Method        Run Time, s
 ================= ============= ===========
-libc              printf          1.01
-libc++            std::ostream    3.04
-{fmt} 1632f72     fmt::print      0.86
-tinyformat 2.0.1  tfm::printf     3.23
-Boost Format 1.67 boost::format   7.98
+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
 ================= ============= ===========
 
-{fmt} is the fastest of the benchmarked methods, ~17% faster than ``printf``.
+{fmt} is the fastest of the benchmarked methods, ~35% faster than ``printf``.
 
 The above results were generated by building ``tinyformat_test.cpp`` on macOS
-10.14.3 with ``clang++ -O3 -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"``
+10.14.6 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>`_.
 
-{fmt} is 10x faster than ``std::ostringstream`` and ``sprintf`` on floating-point
-formatting (`dtoa-benchmark <https://github.com/fmtlib/dtoa-benchmark>`_)
-and as fast as `double-conversion <https://github.com/google/double-conversion>`_:
+{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>`_:
 
-.. image:: https://user-images.githubusercontent.com/576385/54883977-9fe8c000-4e28-11e9-8bde-272d122e7c52.jpg
+.. image:: https://user-images.githubusercontent.com/576385/69767160-cdaca400-112f-11ea-9fc5-347c9f83caad.png
    :target: https://fmt.dev/unknown_mac64_clang10.0.html
 
 Compile time and code bloat
@@ -211,7 +226,6 @@ printf                    2.6                   29                 26
 printf+string            16.4                   29                 26
 iostreams                31.1                   59                 55
 {fmt}                    19.0                   37                 34
-tinyformat               44.0                  103                 97
 Boost Format             91.9                  226                203
 Folly Format            115.7                  101                 88
 ============= =============== ==================== ==================
@@ -232,14 +246,13 @@ printf                    2.2                   33                 30
 printf+string            16.0                   33                 30
 iostreams                28.3                   56                 52
 {fmt}                    18.2                   59                 50
-tinyformat               32.6                   88                 82
 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
-compare formatting function overhead only. Boost Format and tinyformat are
-header-only libraries so they don't provide any linkage options.
+compare formatting function overhead only. Boost Format is a
+header-only library so it doesn't provide any linkage options.
 
 Running the tests
 ~~~~~~~~~~~~~~~~~
@@ -269,12 +282,15 @@ or the bloat test::
 Projects using this library
 ---------------------------
 
-* `0 A.D. <http://play0ad.com/>`_: A free, open-source, cross-platform real-time
-  strategy game
+* `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
-  
+
+* `Aseprite <https://github.com/aseprite/aseprite>`_:
+  Animated sprite editor & pixel art tool 
+
 * `AvioBook <https://www.aviobook.aero/en>`_: A comprehensive aircraft
   operations suite
   
@@ -284,21 +300,12 @@ Projects using this library
 
 * `ccache <https://ccache.dev/>`_: A compiler cache
 
+* `ClickHouse <https://github.com/ClickHouse/ClickHouse>`_: analytical database management system
+
 * `CUAUV <http://cuauv.org/>`_: Cornell University's autonomous underwater
   vehicle
 
-* `HarpyWar/pvpgn <https://github.com/pvpgn/pvpgn-server>`_:
-  Player vs Player Gaming Network with tweaks
-
-* `KBEngine <http://kbengine.org/>`_: An open-source MMOG server engine
-
-* `Keypirinha <http://keypirinha.com/>`_: A semantic launcher for Windows
-
-* `Kodi <https://kodi.tv/>`_ (formerly xbmc): Home theater software
-
-* `Lifeline <https://github.com/peter-clark/lifeline>`_: A 2D game
-
-* `Drake <http://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
@@ -306,17 +313,36 @@ Projects using this library
 
 * `FiveM <https://fivem.net/>`_: a modification framework for GTA V
 
+* `Folly <https://github.com/facebook/folly>`_: Facebook open-source library
+
+* `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
+
+* `Keypirinha <https://keypirinha.com/>`_: A semantic launcher for Windows
+
+* `Kodi <https://kodi.tv/>`_ (formerly xbmc): Home theater software
+
+* `Knuth <https://kth.cash/>`_: High-performance Bitcoin full-node
+
+* `Microsoft Verona <https://github.com/microsoft/verona>`_:
+  Research programming language for concurrent ownership
+
 * `MongoDB <https://mongodb.com/>`_: Distributed document database
 
 * `MongoDB Smasher <https://github.com/duckie/mongo_smasher>`_: A small tool to
   generate randomized datasets
 
-* `OpenSpace <http://openspaceproject.com/>`_: An open-source astrovisualization
-  framework
+* `OpenSpace <https://openspaceproject.com/>`_: An open-source
+  astrovisualization framework
 
-* `PenUltima Online (POL) <http://www.polserver.com/>`_:
+* `PenUltima Online (POL) <https://www.polserver.com/>`_:
   An MMO server, compatible with most Ultima Online clients
 
+* `PyTorch <https://github.com/pytorch/pytorch>`_: An open-source machine
+  learning library
+
 * `quasardb <https://www.quasardb.net/>`_: A distributed, high-performance,
   associative database
 
@@ -325,16 +351,17 @@ Projects using this library
 * `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++
+
 * `rpclib <http://rpclib.net/>`_: A modern C++ msgpack-RPC server and client
   library
 
-* `Saddy <https://github.com/mamontov-cpp/saddy-graphics-engine-2d>`_:
-  Small crossplatform 2D graphic engine
-
-* `Salesforce Analytics Cloud <http://www.salesforce.com/analytics-cloud/overview/>`_:
+* `Salesforce Analytics Cloud
+  <https://www.salesforce.com/analytics-cloud/overview/>`_:
   Business intelligence software
 
-* `Scylla <http://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++
@@ -349,6 +376,9 @@ Projects using this library
 * `TrinityCore <https://github.com/TrinityCore/TrinityCore>`_: Open-source
   MMORPG framework
 
+* `Windows Terminal <https://github.com/microsoft/terminal>`_: The new Windows
+  Terminal
+
 `More... <https://github.com/search?q=fmtlib&type=Code>`_
 
 If you are aware of other projects using this library, please let me know
@@ -373,7 +403,7 @@ The good thing about ``printf`` is that it is pretty fast and readily available
 being a part of the C standard library. The main drawback is that it
 doesn't support user-defined types. ``printf`` also has safety issues although
 they are somewhat mitigated with `__attribute__ ((format (printf, ...))
-<http://gcc.gnu.org/onlinedocs/gcc/Function-Attributes.html>`_ in GCC.
+<https://gcc.gnu.org/onlinedocs/gcc/Function-Attributes.html>`_ in GCC.
 There is a POSIX extension that adds positional arguments required for
 `i18n <https://en.wikipedia.org/wiki/Internationalization_and_localization>`_
 to ``printf`` but it is not a part of C99 and may not be available on some
@@ -412,8 +442,8 @@ Format also has excessive build times and severe code bloat issues (see
 FastFormat
 ~~~~~~~~~~
 
-This is an interesting library which is fast, safe and has positional
-arguments. However it has significant limitations, citing its author:
+This is an interesting library which 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
     current design are:
@@ -422,22 +452,8 @@ arguments. However it has significant limitations, citing its author:
     * Octal/hexadecimal encoding
     * Runtime width/alignment specification
 
-It is also quite big and has a heavy dependency, STLSoft, which might be
-too restrictive for using it in some projects.
-
-Loki SafeFormat
-~~~~~~~~~~~~~~~
-
-SafeFormat is a formatting library which uses ``printf``-like format strings and
-is type safe. It doesn't support user-defined types or positional arguments and
-makes unconventional use of ``operator()`` for passing format arguments.
-
-Tinyformat
-~~~~~~~~~~
-
-This library supports ``printf``-like format strings and is very small .
-It doesn't support positional arguments and wrapping it in C++98 is somewhat
-difficult. Tinyformat relies on iostreams which limits its performance.
+It is also quite big and has a heavy dependency, STLSoft, which might be too
+restrictive for using it in some projects.
 
 Boost Spirit.Karma
 ~~~~~~~~~~~~~~~~~~
@@ -445,32 +461,9 @@ Boost Spirit.Karma
 This is not really 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_int`` on Karma's own benchmark,
-see `Fast integer to string conversion in C++
-<http://zverovich.net/2013/09/07/integer-to-string-conversion-in-cplusplus.html>`_.
-
-FAQ
----
-
-Q: how can I capture formatting arguments and format them later?
-
-A: use ``std::tuple``:
-
-.. code:: c++
-
-   template <typename... Args>
-   auto capture(const Args&... args) {
-     return std::make_tuple(args...);
-   }
-
-   auto print_message = [](const auto&... args) {
-     fmt::print(args...);
-   };
-
-   // Capture and store arguments:
-   auto args = capture("{} {}", 42, "foo");
-   // Do formatting:
-   std::apply(print_message, args);
+than ``fmt::format_to`` with format string compilation on Karma's own benchmark,
+see `Converting a hundred million integers to strings per second
+<http://www.zverovich.net/2020/06/13/fast-int-to-string-revisited.html>`_.
 
 License
 -------
@@ -478,18 +471,19 @@ License
 {fmt} is distributed under the MIT `license
 <https://github.com/fmtlib/fmt/blob/master/LICENSE.rst>`_.
 
-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>`_
-adapted for the current library. 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.
+Documentation License
+---------------------
 
-Acknowledgments
----------------
+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
+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}.
+
+Maintainers
+-----------
 
 The {fmt} library is maintained by Victor Zverovich (`vitaut
 <https://github.com/vitaut>`_) and Jonathan Müller (`foonathan
@@ -498,23 +492,3 @@ 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
 we'll make it right.
-
-The benchmark section of this readme file and the performance tests are taken
-from the excellent `tinyformat <https://github.com/c42f/tinyformat>`_ library
-written by Chris Foster.  Boost Format library is acknowledged transitively
-since it had some influence on tinyformat.
-Some ideas used in the implementation are borrowed from `Loki
-<http://loki-lib.sourceforge.net/>`_ SafeFormat and `Diagnostic API
-<http://clang.llvm.org/doxygen/classclang_1_1Diagnostic.html>`_ in
-`Clang <http://clang.llvm.org/>`_.
-Format string syntax and the documentation are based on Python's `str.format
-<http://docs.python.org/2/library/stdtypes.html#str.format>`_.
-Thanks `Doug Turnbull <https://github.com/softwaredoug>`_ for his valuable
-comments and contribution to the design of the type-safe API and
-`Gregory Czajkowski <https://github.com/gcflymoto>`_ for implementing binary
-formatting. Thanks `Ruslan Baratov <https://github.com/ruslo>`_ for comprehensive
-`comparison of integer formatting algorithms <https://github.com/ruslo/int-dec-format-tests>`_
-and useful comments regarding performance, `Boris Kaul <https://github.com/localvoid>`_ for
-`C++ counting digits benchmark <https://github.com/localvoid/cxx-benchmark-count-digits>`_.
-Thanks to `CarterLi <https://github.com/CarterLi>`_ for contributing various
-improvements to the code.

doc/CMakeLists.txt

@@ -9,4 +9,5 @@ add_custom_target(doc
   SOURCES api.rst syntax.rst usage.rst build.py conf.py _templates/layout.html)
 
 install(DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}/html/
-        DESTINATION share/doc/fmt OPTIONAL)
+        DESTINATION share/doc/fmt OPTIONAL
+        PATTERN ".doctrees" EXCLUDE)

doc/_templates/layout.html

@@ -6,14 +6,13 @@
 <meta name="author" content="Victor Zverovich">
 <link rel="stylesheet" href="_static/fmt.css">
 {# Google Analytics #}
+<script async src="https://www.googletagmanager.com/gtag/js?id=UA-20116650-4"></script>
 <script>
-  (function(i,s,o,g,r,a,m){i['GoogleAnalyticsObject']=r;i[r]=i[r]||function(){
-    (i[r].q=i[r].q||[]).push(arguments)},i[r].l=1*new Date();
-    a=s.createElement(o),m=s.getElementsByTagName(o)[0];a.async=1;
-    a.src=g;m.parentNode.insertBefore(a,m)
-  })(window,document,'script','//www.google-analytics.com/analytics.js','ga');
-  ga('create', 'UA-20116650-4', 'fmtlib.net');
-  ga('send', 'pageview');
+  window.dataLayer = window.dataLayer || [];
+  function gtag(){dataLayer.push(arguments);}
+  gtag('js', new Date());
+
+  gtag('config', 'UA-20116650-4');
 </script>
 {% endblock %}
 
@@ -84,7 +83,7 @@
 <div class="jumbotron">
   <div class="tb-container">
     <h1>{fmt}</h1>
-    <p class="lead">Small, safe and fast formatting library</p>
+    <p class="lead">A modern formatting library</p>
     <div class="btn-group" role="group">
       {% set name = 'fmt' if version.split('.')[0]|int >= 3 else 'cppformat' %}
       <a class="btn btn-success"

doc/api.rst

@@ -9,15 +9,17 @@ 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, output iterator and user-defined type support
+  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/chrono.h <chrono-api>`: date and time formatting
+* :ref:`fmt/compile.h <compile-api>`: format string compilation
 * :ref:`fmt/ostream.h <ostream-api>`: ``std::ostream`` support
 * :ref:`fmt/printf.h <printf-api>`: ``printf`` formatting
 
 All functions and types provided by the library reside in namespace ``fmt`` and
-macros have prefix ``FMT_`` or ``fmt``.
+macros have prefix ``FMT_``.
 
 .. _core-api:
 
@@ -43,7 +45,7 @@ participate in an overload resolution if the latter is not a string.
 .. _format:
 
 .. doxygenfunction:: format(const S&, Args&&...)
-.. doxygenfunction:: vformat(const S&, basic_format_args<buffer_context<Char>>)
+.. doxygenfunction:: vformat(const S&, basic_format_args<buffer_context<type_identity_t<Char>>>)
 
 .. _print:
 
@@ -52,7 +54,6 @@ participate in an overload resolution if the latter is not a string.
 
 .. doxygenfunction:: print(std::FILE *, const S&, Args&&...)
 .. doxygenfunction:: vprint(std::FILE *, string_view, format_args)
-.. doxygenfunction:: vprint(std::FILE *, wstring_view, wformat_args)
 
 Named Arguments
 ---------------
@@ -69,6 +70,9 @@ Argument Lists
 .. doxygenclass:: fmt::format_arg_store
    :members:
 
+.. doxygenclass:: fmt::dynamic_format_arg_store
+   :members:
+
 .. doxygenclass:: fmt::basic_format_args
    :members:
 
@@ -86,19 +90,35 @@ Compatibility
 .. 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, output iterator and user-defined type support.
+string checks, wide string, output iterator and user-defined type support.
 
 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.
+
 .. doxygendefine:: FMT_STRING
-.. doxygendefine:: fmt
 
 Formatting User-defined Types
 -----------------------------
@@ -110,40 +130,65 @@ template and implement ``parse`` and ``format`` methods::
 
   struct point { double x, y; };
 
-  namespace fmt {
   template <>
-  struct formatter<point> {
-    template <typename ParseContext>
-    constexpr auto parse(ParseContext &ctx) { return ctx.begin(); }
+  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
+      // [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
+      //
+      //   fmt::format("{:f} - point of interest", point{1, 2});
+      //
+      // the range will contain "f} - point of interest". The formatter should
+      // 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 '}'.
+
+      // 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");
+
+      // Return an iterator past the end of the parsed range:
+      return it;
+    }
+
+    // Formats the point p using the parsed format specification (presentation)
+    // stored in this formatter.
     template <typename FormatContext>
-    auto format(const point &p, FormatContext &ctx) {
-      return format_to(ctx.out(), "({:.1f}, {:.1f})", p.x, p.y);
+    auto format(const point& p, FormatContext& ctx) {
+    // auto format(const point &p, FormatContext &ctx) -> decltype(ctx.out()) // c++11
+      // ctx.out() is an output iterator to write to.
+      return format_to(
+          ctx.out(),
+          presentation == 'f' ? "({:.1f}, {:.1f})" : "({:.1e}, {:.1e})",
+          p.x, p.y);
     }
   };
-  }
 
 Then you can pass objects of type ``point`` to any formatting function::
 
   point p = {1, 2};
-  std::string s = fmt::format("{}", p);
+  std::string s = fmt::format("{:f}", p);
   // s == "(1.0, 2.0)"
 
-In the example above the ``formatter<point>::parse`` function ignores the
-contents of the format string referred to by ``ctx.begin()`` so the object will
-always be formatted in the same way. See ``formatter<tm>::parse`` in
-:file:`fmt/chrono.h` for an advanced example of how to parse the format string and
-customize the formatted output.
-
-You can also reuse existing formatters, for example::
+You can also reuse existing formatters via inheritance or composition, for
+example::
 
   enum class color {red, green, blue};
 
-  template <>
-  struct fmt::formatter<color>: formatter<string_view> {
+  template <> struct fmt::formatter<color>: formatter<string_view> {
     // parse is inherited from formatter<string_view>.
     template <typename FormatContext>
-    auto format(color c, FormatContext &ctx) {
+    auto format(color c, FormatContext& ctx) {
       string_view name = "unknown";
       switch (c) {
       case color::red:   name = "red"; break;
@@ -154,6 +199,15 @@ You can also reuse existing formatters, for example::
     }
   };
 
+Since ``parse`` is inherited from ``formatter<string_view>`` it will recognize
+all string format specifications, for example
+
+.. code-block:: c++
+
+   fmt::format("{:>10}", color::blue)
+
+will return ``"      blue"``.
+
 You can also write a formatter for a hierarchy of classes::
 
   #include <type_traits>
@@ -183,6 +237,9 @@ You can also write a formatter for a hierarchy of classes::
     fmt::print("{}", a); // prints "B"
   }
 
+.. doxygenclass:: fmt::basic_format_parse_context
+   :members:
+
 Output Iterator Support
 -----------------------
 
@@ -196,9 +253,9 @@ Literal-based API
 
 The following user-defined literals are defined in ``fmt/format.h``.
 
-.. doxygenfunction:: operator""_format(const char *, std::size_t)
+.. doxygenfunction:: operator""_format(const char *, size_t)
 
-.. doxygenfunction:: operator""_a(const char *, std::size_t)
+.. doxygenfunction:: operator""_a(const char *, size_t)
 
 Utilities
 ---------
@@ -219,6 +276,9 @@ Utilities
 
 .. doxygenfunction:: fmt::join(It, It, string_view)
 
+.. doxygenclass:: fmt::detail::buffer
+   :members:
+
 .. doxygenclass:: fmt::basic_memory_buffer
    :protected-members:
    :members:
@@ -266,7 +326,7 @@ allocator::
     template <typename ...Args>
     inline custom_string format(custom_allocator alloc,
                                 fmt::string_view format_str,
-                                const Args & ... args) {
+                                const Args& ... args) {
       return vformat(alloc, format_str, fmt::make_format_args(args...));
     }
 
@@ -275,50 +335,6 @@ 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.
 
-Custom Formatting of Built-in Types
------------------------------------
-
-It is possible to change the way arguments are formatted by providing a
-custom argument formatter class::
-
-  using arg_formatter = fmt::arg_formatter<fmt::buffer_range<char>>;
-
-  // A custom argument formatter that formats negative integers as unsigned
-  // with the ``x`` format specifier.
-  class custom_arg_formatter : public arg_formatter {
-   public:
-    custom_arg_formatter(fmt::format_context& ctx,
-                         fmt::format_parse_context* parse_ctx = nullptr,
-                         fmt::format_specs* spec = nullptr)
-      : arg_formatter(ctx, parse_ctx, spec) {}
-
-    using arg_formatter::operator();
-
-    auto operator()(int value) {
-      if (specs() && specs()->type == 'x')
-        return (*this)(static_cast<unsigned>(value)); // convert to unsigned and format
-      return arg_formatter::operator()(value);
-    }
-  };
-
-  std::string custom_vformat(fmt::string_view format_str, fmt::format_args args) {
-    fmt::memory_buffer buffer;
-    // Pass custom argument formatter as a template arg to vformat_to.
-    fmt::vformat_to<custom_arg_formatter>(buffer, format_str, args);
-    return fmt::to_string(buffer);
-  }
-
-  template <typename ...Args>
-  inline std::string custom_format(
-      fmt::string_view format_str, const Args &... args) {
-    return custom_vformat(format_str, fmt::make_format_args(args...));
-  }
-
-  std::string s = custom_format("{:x}", -42); // s == "ffffffd6"
-
-.. doxygenclass:: fmt::arg_formatter
-   :members:
-
 .. _ranges-api:
 
 Ranges and Tuple Formatting
@@ -357,11 +373,26 @@ formatting::
 
   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}.", *std::localtime(&t));
+  fmt::print("The date is {:%Y-%m-%d}.", fmt::localtime(t));
 
 The format string syntax is described in the documentation of
 `strftime <http://en.cppreference.com/w/cpp/chrono/c/strftime>`_.
 
+.. _compile-api:
+
+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.
+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
+
 .. _ostream-api:
 
 ``std::ostream`` Support
@@ -377,7 +408,7 @@ user-defined types that have overloaded ``operator<<``::
   public:
     date(int year, int month, int day): year_(year), month_(month), day_(day) {}
 
-    friend std::ostream &operator<<(std::ostream &os, const date &d) {
+    friend std::ostream& operator<<(std::ostream& os, const date& d) {
       return os << d.year_ << '-' << d.month_ << '-' << d.day_;
     }
   };
@@ -406,3 +437,19 @@ argument type doesn't match its format specification.
 .. doxygenfunction:: fprintf(std::basic_ostream<Char>&, const S&, const Args&...)
 
 .. doxygenfunction:: sprintf(const S&, const Args&...)
+
+Compatibility with C++20 ``std::format``
+========================================
+
+{fmt} implements nearly all of the `C++20 formatting library
+<https://en.cppreference.com/w/cpp/utility/format>`_ with the following
+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.

doc/build.py

@@ -6,7 +6,7 @@ import errno, os, shutil, sys, tempfile
 from subprocess import check_call, check_output, CalledProcessError, Popen, PIPE
 from distutils.version import LooseVersion
 
-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']
+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']
 
 def pip_install(package, commit=None, **kwargs):
   "Install package using pip."
@@ -74,8 +74,8 @@ def build_docs(version='dev', **kwargs):
       GENERATE_MAN      = NO
       GENERATE_RTF      = NO
       CASE_SENSE_NAMES  = NO
-      INPUT             = {0}/core.h {0}/format.h {0}/ostream.h \
-                          {0}/printf.h {0}/time.h
+      INPUT             = {0}/core.h {0}/compile.h {0}/format.h {0}/os.h \
+                          {0}/ostream.h {0}/printf.h {0}/time.h
       QUIET             = YES
       JAVADOC_AUTOBRIEF = YES
       AUTOLINK_SUPPORT  = NO

doc/index.rst

@@ -1,17 +1,18 @@
 Overview
 ========
 
-**fmt** is an open-source formatting library.
-It can be used as a fast and safe alternative to printf and IOStreams.
+**{fmt}** is an open-source formatting library providing a fast and safe
+alternative to C stdio and C++ iostreams.
 
 .. raw:: html
 
    <div class="panel panel-default">
      <div class="panel-heading">What users say:</div>
      <div class="panel-body">
-       Thanks for creating this library. It’s been a hole in C++ for a long
-       time. I’ve used both boost::format and loki::SPrintf, and neither felt
-       like the right answer. This does.
+       Thanks for creating this library. It’s been a hole in C++ for
+       a long time. I’ve used both <code>boost::format</code> and
+       <code>loki::SPrintf</code>, and neither felt like the right answer.
+       This does.
      </div>
    </div>
 
@@ -20,12 +21,13 @@ It can be used as a fast and safe alternative to printf and IOStreams.
 Format API
 ----------
 
-The replacement-based Format API provides a safe alternative to ``printf``,
-``sprintf`` and friends with comparable or `better performance
-<http://zverovich.net/2013/09/07/integer-to-string-conversion-in-cplusplus.html>`_.
+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>`_
+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 Python:
+`str.format <http://docs.python.org/3/library/stdtypes.html#str.format>`_ in
+Python:
 
 .. code:: c++
 
@@ -60,7 +62,7 @@ The Format API also supports positional arguments useful for localization:
   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 values are being inserted:
+what goes where when multiple arguments are being formatted:
 
 .. code:: c++
 
@@ -72,21 +74,10 @@ an alternative, slightly terser syntax for named arguments:
 
 .. code:: c++
 
+  using namespace fmt::literals;
   fmt::print("Hello, {name}! The answer is {number}. Goodbye, {name}.",
              "name"_a="World", "number"_a=42);
 
-The ``_format`` suffix may be used to format string literals similar to Python:
-
-.. code:: c++
-
-  std::string message = "{0}{1}{0}"_format("abra", "cad"); 
-
-Other than the placement of the format string on the left of the operator, 
-``_format`` is functionally identical to ``fmt::format``. In order to use the 
-literal operators, they must be made visible with the directive 
-``using namespace fmt::literals;``. Note that this brings in only ``_a`` and 
-``_format`` but nothing else from the ``fmt`` namespace.
-
 .. _safety:
 
 Safety
@@ -106,11 +97,10 @@ string", because the argument ``"forty-two"`` is a string while the format code
 
 .. code:: c++
 
-  format(fmt("The answer is {:d}"), "forty-two");
+  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 how to enable
-compile-time checks.
+relaxed ``constexpr``. See `here <api.html#c.fmt>`_ for details.
 
 The following code
 
@@ -178,13 +168,13 @@ The library is highly portable and relies only on a small set of C++11 features:
 * 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
+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.
 
 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 in this case. For example,
+output of ``printf`` is platform-dependent. For example,
 
 .. code::
 
@@ -197,9 +187,9 @@ always prints ``inf``.
 Ease of Use
 -----------
 
-fmt has a small self-contained code base with the core library consisting of
+{fmt} has a small self-contained code base with the core library consisting of
 just three header files and no external dependencies.
-A permissive BSD `license <https://github.com/fmtlib/fmt#license>`_ allows
+A permissive MIT `license <https://github.com/fmtlib/fmt#license>`_ allows
 using the library both in open-source and commercial projects.
 
 .. raw:: html

doc/syntax.rst

@@ -76,19 +76,19 @@ The general form of a *standard format specifier* is:
 
 .. productionlist:: sf
    format_spec: [[`fill`]`align`][`sign`]["#"]["0"][`width`]["." `precision`][`type`]
-   fill: <a character other than '{', '}' or '\0'>
-   align: "<" | ">" | "=" | "^"
+   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" | "p" | "s"
-   int_type: "b" | "B" | "d" | "n" | "o" | "x" | "X"
+   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"
 
-The *fill* character can be any character other than '{', '}' or '\\0'. The
-presence of a fill character is signaled by the character following it, which
-must be one of the alignment options.  If the second character of *format_spec*
-is not a valid alignment option, then it is assumed that both the fill character
-and the alignment option are absent.
+The *fill* character can be any Unicode code point other than ``'{'`` or
+``'}'``. The presence of a fill character is signaled by the character following
+it, which must be one of the alignment options. If the second character of
+*format_spec* is not a valid alignment option, then it is assumed that both the
+fill character and the alignment option are absent.
 
 The meaning of the various alignment options is as follows:
 
@@ -143,7 +143,7 @@ conversions, trailing zeros are not removed from the result.
 .. ifconfig:: False
 
    The ``','`` option signals the use of a comma for a thousands separator.
-   For a locale aware separator, use the ``'n'`` integer presentation type
+   For a locale aware separator, use the ``'L'`` integer presentation type
    instead.
 
 *width* is a decimal integer defining the minimum field width.  If not
@@ -214,9 +214,9 @@ The available integer presentation types are:
 |         | ``'#'`` option with this type adds the prefix ``"0X"``   |
 |         | to the output value.                                     |
 +---------+----------------------------------------------------------+
-| ``'n'`` | Number. This is the same as ``'d'``, except that it uses |
-|         | the current locale setting to insert the appropriate     |
-|         | number separator characters.                             |
+| ``'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'``.                                     |
 +---------+----------------------------------------------------------+
@@ -261,13 +261,9 @@ 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. |
 +---------+----------------------------------------------------------+
-| ``'n'`` | Number. This is the same as ``'g'``, except that it uses |
-|         | the current locale setting to insert the appropriate     |
-|         | number separator characters.                             |
-+---------+----------------------------------------------------------+
-| ``'%'`` | Fixed point as a percentage. This is similar to ``'f'``, |
-|         | but the argument is multiplied by 100 and a percent sign |
-|         | ``%`` is appended.                                       |
+| ``'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       |
@@ -324,79 +320,94 @@ following examples.
 
 Accessing arguments by position::
 
-   format("{0}, {1}, {2}", 'a', 'b', 'c');
+   fmt::format("{0}, {1}, {2}", 'a', 'b', 'c');
    // Result: "a, b, c"
-   format("{}, {}, {}", 'a', 'b', 'c');
+   fmt::format("{}, {}, {}", 'a', 'b', 'c');
    // Result: "a, b, c"
-   format("{2}, {1}, {0}", 'a', 'b', 'c');
+   fmt::format("{2}, {1}, {0}", 'a', 'b', 'c');
    // Result: "c, b, a"
-   format("{0}{1}{0}", "abra", "cad");  // arguments' indices can be repeated
+   fmt::format("{0}{1}{0}", "abra", "cad");  // arguments' indices can be repeated
    // Result: "abracadabra"
 
 Aligning the text and specifying a width::
 
-   format("{:<30}", "left aligned");
+   fmt::format("{:<30}", "left aligned");
    // Result: "left aligned                  "
-   format("{:>30}", "right aligned");
+   fmt::format("{:>30}", "right aligned");
    // Result: "                 right aligned"
-   format("{:^30}", "centered");
+   fmt::format("{:^30}", "centered");
    // Result: "           centered           "
-   format("{:*^30}", "centered");  // use '*' as a fill char
+   fmt::format("{:*^30}", "centered");  // use '*' as a fill char
    // Result: "***********centered***********"
 
 Dynamic width::
 
-   format("{:<{}}", "left aligned", 30);
+   fmt::format("{:<{}}", "left aligned", 30);
    // Result: "left aligned                  "
 
 Dynamic precision::
 
-   format("{:.{}f}", 3.14, 1);
+   fmt::format("{:.{}f}", 3.14, 1);
    // Result: "3.1"
 
 Replacing ``%+f``, ``%-f``, and ``% f`` and specifying a sign::
 
-   format("{:+f}; {:+f}", 3.14, -3.14);  // show it always
+   fmt::format("{:+f}; {:+f}", 3.14, -3.14);  // show it always
    // Result: "+3.140000; -3.140000"
-   format("{: f}; {: f}", 3.14, -3.14);  // show a space for positive numbers
+   fmt::format("{: f}; {: f}", 3.14, -3.14);  // show a space for positive numbers
    // Result: " 3.140000; -3.140000"
-   format("{:-f}; {:-f}", 3.14, -3.14);  // show only the minus -- same as '{:f}; {:f}'
+   fmt::format("{:-f}; {:-f}", 3.14, -3.14);  // show only the minus -- same as '{:f}; {:f}'
    // Result: "3.140000; -3.140000"
 
-As a percentage::
-
-   format("{0:f} or {0:%}", .635);
-   // Result: "0.635000 or 63.500000%"
-   format("{:*^{}.{}%}", 1., 15, 2); // With fill, dynamic width and dynamic precision.
-   // Result: "****100.00%****"
-
 Replacing ``%x`` and ``%o`` and converting the value to different bases::
 
-   format("int: {0:d};  hex: {0:x};  oct: {0:o}; bin: {0:b}", 42);
+   fmt::format("int: {0:d};  hex: {0:x};  oct: {0:o}; bin: {0:b}", 42);
    // Result: "int: 42;  hex: 2a;  oct: 52; bin: 101010"
    // with 0x or 0 or 0b as prefix:
-   format("int: {0:d};  hex: {0:#x};  oct: {0:#o};  bin: {0:#b}", 42);
+   fmt::format("int: {0:d};  hex: {0:#x};  oct: {0:#o};  bin: {0:#b}", 42);
    // Result: "int: 42;  hex: 0x2a;  oct: 052;  bin: 0b101010"
 
 Padded hex byte with prefix and always prints both hex characters::
 
-   format("{:#04x}", 0);
+   fmt::format("{:#04x}", 0);
    // Result: "0x00"
 
+Box drawing using Unicode fill::
+
+   fmt::print(
+     "┌{0:─^{2}}┐\n"
+     "│{1: ^{2}}│\n"
+     "└{0:─^{2}}┘\n", "", "Hello, world!", 20);
+
+prints::
+
+   ┌────────────────────┐
+   │   Hello, world!    │
+   └────────────────────┘
+
+Using type-specific formatting::
+
+   #include <fmt/chrono.h>
+
+   auto t = tm();
+   t.tm_year = 2010 - 1900;
+   t.tm_mon = 6;
+   t.tm_mday = 4;
+   t.tm_hour = 12;
+   t.tm_min = 15;
+   t.tm_sec = 58;
+   fmt::print("{:%Y-%m-%d %H:%M:%S}", t);
+   // Prints: 2010-08-04 12:15:58
+
+Using the comma as a thousands separator::
+
+   #include <fmt/locale.h>
+
+   auto s = fmt::format(std::locale("en_US.UTF-8"), "{:L}", 1234567890);
+   // s == "1,234,567,890"
+
 .. ifconfig:: False
 
-   Using the comma as a thousands separator::
-
-      format("{:,}", 1234567890);
-      '1,234,567,890'
-
-   Using type-specific formatting::
-
-      >>> import datetime
-      >>> d = datetime.datetime(2010, 7, 4, 12, 15, 58)
-      Format("{:%Y-%m-%d %H:%M:%S}") << d)
-      '2010-07-04 12:15:58'
-
    Nesting arguments and more complex examples::
 
       >>> for align, text in zip('<^>', ['left', 'center', 'right']):

doc/usage.rst

@@ -103,7 +103,33 @@ the previous section. Then compile the ``doc`` target/project, for example::
   make doc
 
 This will generate the HTML documentation in ``doc/html``.
-  
+
+Conda
+=====
+
+fmt can be installed on Linux, macOS and Windows with
+`Conda <https://docs.conda.io/en/latest/>`__, using its
+`conda-forge <https://conda-forge.org>`__
+`package <https://github.com/conda-forge/fmt-feedstock>`__, as follows::
+
+  conda install -c conda-forge fmt
+
+Vcpkg
+=====
+
+You can download and install fmt using the `vcpkg
+<https://github.com/Microsoft/vcpkg>`__ dependency manager::
+
+  git clone https://github.com/Microsoft/vcpkg.git
+  cd vcpkg
+  ./bootstrap-vcpkg.sh
+  ./vcpkg integrate install
+  ./vcpkg install fmt
+
+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.
+
 Android NDK
 ===========
 

include/fmt/chrono.h

@@ -8,35 +8,311 @@
 #ifndef FMT_CHRONO_H_
 #define FMT_CHRONO_H_
 
-#include "format.h"
-#include "locale.h"
-
 #include <chrono>
 #include <ctime>
 #include <locale>
 #include <sstream>
 
-// enable safe chrono durations, unless explicitly disabled
+#include "format.h"
+#include "locale.h"
+
+FMT_BEGIN_NAMESPACE
+
+// Enable safe chrono durations, unless explicitly disabled.
 #ifndef FMT_SAFE_DURATION_CAST
 #  define FMT_SAFE_DURATION_CAST 1
 #endif
-
 #if FMT_SAFE_DURATION_CAST
-#  include "safe-duration-cast.h"
-#endif
 
-FMT_BEGIN_NAMESPACE
+// For conversion between std::chrono::durations without undefined
+// behaviour or erroneous results.
+// This is a stripped down version of duration_cast, for inclusion in fmt.
+// See https://github.com/pauldreik/safe_duration_cast
+//
+// Copyright Paul Dreik 2019
+namespace safe_duration_cast {
+
+template <typename To, typename From,
+          FMT_ENABLE_IF(!std::is_same<From, To>::value &&
+                        std::numeric_limits<From>::is_signed ==
+                            std::numeric_limits<To>::is_signed)>
+FMT_CONSTEXPR To lossless_integral_conversion(const From from, int& ec) {
+  ec = 0;
+  using F = std::numeric_limits<From>;
+  using T = std::numeric_limits<To>;
+  static_assert(F::is_integer, "From must be integral");
+  static_assert(T::is_integer, "To must be integral");
+
+  // A and B are both signed, or both unsigned.
+  if (F::digits <= T::digits) {
+    // From fits in To without any problem.
+  } else {
+    // From does not always fit in To, resort to a dynamic check.
+    if (from < (T::min)() || from > (T::max)()) {
+      // outside range.
+      ec = 1;
+      return {};
+    }
+  }
+  return static_cast<To>(from);
+}
+
+/**
+ * converts From to To, without loss. If the dynamic value of from
+ * can't be converted to To without loss, ec is set.
+ */
+template <typename To, typename From,
+          FMT_ENABLE_IF(!std::is_same<From, To>::value &&
+                        std::numeric_limits<From>::is_signed !=
+                            std::numeric_limits<To>::is_signed)>
+FMT_CONSTEXPR To lossless_integral_conversion(const From from, int& ec) {
+  ec = 0;
+  using F = std::numeric_limits<From>;
+  using T = std::numeric_limits<To>;
+  static_assert(F::is_integer, "From must be integral");
+  static_assert(T::is_integer, "To must be integral");
+
+  if (F::is_signed && !T::is_signed) {
+    // From may be negative, not allowed!
+    if (fmt::detail::is_negative(from)) {
+      ec = 1;
+      return {};
+    }
+
+    // From is positive. Can it always fit in To?
+    if (F::digits <= T::digits) {
+      // yes, From always fits in To.
+    } else {
+      // from may not fit in To, we have to do a dynamic check
+      if (from > static_cast<From>((T::max)())) {
+        ec = 1;
+        return {};
+      }
+    }
+  }
+
+  if (!F::is_signed && T::is_signed) {
+    // can from be held in To?
+    if (F::digits < T::digits) {
+      // yes, From always fits in To.
+    } else {
+      // from may not fit in To, we have to do a dynamic check
+      if (from > static_cast<From>((T::max)())) {
+        // outside range.
+        ec = 1;
+        return {};
+      }
+    }
+  }
+
+  // reaching here means all is ok for lossless conversion.
+  return static_cast<To>(from);
+
+}  // function
+
+template <typename To, typename From,
+          FMT_ENABLE_IF(std::is_same<From, To>::value)>
+FMT_CONSTEXPR To lossless_integral_conversion(const From from, int& ec) {
+  ec = 0;
+  return from;
+}  // function
+
+// clang-format off
+/**
+ * converts From to To if possible, otherwise ec is set.
+ *
+ * input                            |    output
+ * ---------------------------------|---------------
+ * NaN                              | NaN
+ * Inf                              | Inf
+ * normal, fits in output           | converted (possibly lossy)
+ * normal, does not fit in output   | ec is set
+ * subnormal                        | best effort
+ * -Inf                             | -Inf
+ */
+// clang-format on
+template <typename To, typename From,
+          FMT_ENABLE_IF(!std::is_same<From, To>::value)>
+FMT_CONSTEXPR To safe_float_conversion(const From from, int& ec) {
+  ec = 0;
+  using T = std::numeric_limits<To>;
+  static_assert(std::is_floating_point<From>::value, "From must be floating");
+  static_assert(std::is_floating_point<To>::value, "To must be floating");
+
+  // catch the only happy case
+  if (std::isfinite(from)) {
+    if (from >= T::lowest() && from <= (T::max)()) {
+      return static_cast<To>(from);
+    }
+    // not within range.
+    ec = 1;
+    return {};
+  }
+
+  // nan and inf will be preserved
+  return static_cast<To>(from);
+}  // function
+
+template <typename To, typename From,
+          FMT_ENABLE_IF(std::is_same<From, To>::value)>
+FMT_CONSTEXPR To safe_float_conversion(const From from, int& ec) {
+  ec = 0;
+  static_assert(std::is_floating_point<From>::value, "From must be floating");
+  return from;
+}
+
+/**
+ * safe duration cast between integral durations
+ */
+template <typename To, typename FromRep, typename FromPeriod,
+          FMT_ENABLE_IF(std::is_integral<FromRep>::value),
+          FMT_ENABLE_IF(std::is_integral<typename To::rep>::value)>
+To safe_duration_cast(std::chrono::duration<FromRep, FromPeriod> from,
+                      int& ec) {
+  using From = std::chrono::duration<FromRep, FromPeriod>;
+  ec = 0;
+  // the basic idea is that we need to convert from count() in the from type
+  // to count() in the To type, by multiplying it with this:
+  struct Factor
+      : std::ratio_divide<typename From::period, typename To::period> {};
+
+  static_assert(Factor::num > 0, "num must be positive");
+  static_assert(Factor::den > 0, "den must be positive");
+
+  // the conversion is like this: multiply from.count() with Factor::num
+  // /Factor::den and convert it to To::rep, all this without
+  // overflow/underflow. let's start by finding a suitable type that can hold
+  // both To, From and Factor::num
+  using IntermediateRep =
+      typename std::common_type<typename From::rep, typename To::rep,
+                                decltype(Factor::num)>::type;
+
+  // safe conversion to IntermediateRep
+  IntermediateRep count =
+      lossless_integral_conversion<IntermediateRep>(from.count(), ec);
+  if (ec) {
+    return {};
+  }
+  // multiply with Factor::num without overflow or underflow
+  if (Factor::num != 1) {
+    const auto max1 = detail::max_value<IntermediateRep>() / Factor::num;
+    if (count > max1) {
+      ec = 1;
+      return {};
+    }
+    const auto min1 =
+        (std::numeric_limits<IntermediateRep>::min)() / Factor::num;
+    if (count < min1) {
+      ec = 1;
+      return {};
+    }
+    count *= Factor::num;
+  }
+
+  // this can't go wrong, right? den>0 is checked earlier.
+  if (Factor::den != 1) {
+    count /= Factor::den;
+  }
+  // convert to the to type, safely
+  using ToRep = typename To::rep;
+  const ToRep tocount = lossless_integral_conversion<ToRep>(count, ec);
+  if (ec) {
+    return {};
+  }
+  return To{tocount};
+}
+
+/**
+ * safe duration_cast between floating point durations
+ */
+template <typename To, typename FromRep, typename FromPeriod,
+          FMT_ENABLE_IF(std::is_floating_point<FromRep>::value),
+          FMT_ENABLE_IF(std::is_floating_point<typename To::rep>::value)>
+To safe_duration_cast(std::chrono::duration<FromRep, FromPeriod> from,
+                      int& ec) {
+  using From = std::chrono::duration<FromRep, FromPeriod>;
+  ec = 0;
+  if (std::isnan(from.count())) {
+    // nan in, gives nan out. easy.
+    return To{std::numeric_limits<typename To::rep>::quiet_NaN()};
+  }
+  // maybe we should also check if from is denormal, and decide what to do about
+  // it.
+
+  // +-inf should be preserved.
+  if (std::isinf(from.count())) {
+    return To{from.count()};
+  }
+
+  // the basic idea is that we need to convert from count() in the from type
+  // to count() in the To type, by multiplying it with this:
+  struct Factor
+      : std::ratio_divide<typename From::period, typename To::period> {};
+
+  static_assert(Factor::num > 0, "num must be positive");
+  static_assert(Factor::den > 0, "den must be positive");
+
+  // the conversion is like this: multiply from.count() with Factor::num
+  // /Factor::den and convert it to To::rep, all this without
+  // overflow/underflow. let's start by finding a suitable type that can hold
+  // both To, From and Factor::num
+  using IntermediateRep =
+      typename std::common_type<typename From::rep, typename To::rep,
+                                decltype(Factor::num)>::type;
+
+  // force conversion of From::rep -> IntermediateRep to be safe,
+  // even if it will never happen be narrowing in this context.
+  IntermediateRep count =
+      safe_float_conversion<IntermediateRep>(from.count(), ec);
+  if (ec) {
+    return {};
+  }
+
+  // multiply with Factor::num without overflow or underflow
+  if (Factor::num != 1) {
+    constexpr auto max1 = detail::max_value<IntermediateRep>() /
+                          static_cast<IntermediateRep>(Factor::num);
+    if (count > max1) {
+      ec = 1;
+      return {};
+    }
+    constexpr auto min1 = std::numeric_limits<IntermediateRep>::lowest() /
+                          static_cast<IntermediateRep>(Factor::num);
+    if (count < min1) {
+      ec = 1;
+      return {};
+    }
+    count *= static_cast<IntermediateRep>(Factor::num);
+  }
+
+  // this can't go wrong, right? den>0 is checked earlier.
+  if (Factor::den != 1) {
+    using common_t = typename std::common_type<IntermediateRep, intmax_t>::type;
+    count /= static_cast<common_t>(Factor::den);
+  }
+
+  // convert to the to type, safely
+  using ToRep = typename To::rep;
+
+  const ToRep tocount = safe_float_conversion<ToRep>(count, ec);
+  if (ec) {
+    return {};
+  }
+  return To{tocount};
+}
+}  // namespace safe_duration_cast
+#endif
 
 // Prevents expansion of a preceding token as a function-style macro.
 // Usage: f FMT_NOMACRO()
 #define FMT_NOMACRO
 
-namespace internal {
+namespace detail {
 inline null<> localtime_r FMT_NOMACRO(...) { return null<>(); }
 inline null<> localtime_s(...) { return null<>(); }
 inline null<> gmtime_r(...) { return null<>(); }
 inline null<> gmtime_s(...) { return null<>(); }
-}  // namespace internal
+}  // namespace detail
 
 // Thread-safe replacement for std::localtime
 inline std::tm localtime(std::time_t time) {
@@ -47,22 +323,22 @@ inline std::tm localtime(std::time_t time) {
     dispatcher(std::time_t t) : time_(t) {}
 
     bool run() {
-      using namespace fmt::internal;
+      using namespace fmt::detail;
       return handle(localtime_r(&time_, &tm_));
     }
 
     bool handle(std::tm* tm) { return tm != nullptr; }
 
-    bool handle(internal::null<>) {
-      using namespace fmt::internal;
+    bool handle(detail::null<>) {
+      using namespace fmt::detail;
       return fallback(localtime_s(&tm_, &time_));
     }
 
     bool fallback(int res) { return res == 0; }
 
 #if !FMT_MSC_VER
-    bool fallback(internal::null<>) {
-      using namespace fmt::internal;
+    bool fallback(detail::null<>) {
+      using namespace fmt::detail;
       std::tm* tm = std::localtime(&time_);
       if (tm) tm_ = *tm;
       return tm != nullptr;
@@ -84,21 +360,21 @@ inline std::tm gmtime(std::time_t time) {
     dispatcher(std::time_t t) : time_(t) {}
 
     bool run() {
-      using namespace fmt::internal;
+      using namespace fmt::detail;
       return handle(gmtime_r(&time_, &tm_));
     }
 
     bool handle(std::tm* tm) { return tm != nullptr; }
 
-    bool handle(internal::null<>) {
-      using namespace fmt::internal;
+    bool handle(detail::null<>) {
+      using namespace fmt::detail;
       return fallback(gmtime_s(&tm_, &time_));
     }
 
     bool fallback(int res) { return res == 0; }
 
 #if !FMT_MSC_VER
-    bool fallback(internal::null<>) {
+    bool fallback(detail::null<>) {
       std::tm* tm = std::gmtime(&time_);
       if (tm) tm_ = *tm;
       return tm != nullptr;
@@ -111,17 +387,17 @@ inline std::tm gmtime(std::time_t time) {
   return gt.tm_;
 }
 
-namespace internal {
-inline std::size_t strftime(char* str, std::size_t count, const char* format,
-                            const std::tm* time) {
+namespace detail {
+inline size_t strftime(char* str, size_t count, const char* format,
+                       const std::tm* time) {
   return std::strftime(str, count, format, time);
 }
 
-inline std::size_t strftime(wchar_t* str, std::size_t count,
-                            const wchar_t* format, const std::tm* time) {
+inline size_t strftime(wchar_t* str, size_t count, const wchar_t* format,
+                       const std::tm* time) {
   return std::wcsftime(str, count, format, time);
 }
-}  // namespace internal
+}  // namespace detail
 
 template <typename Char> struct formatter<std::tm, Char> {
   template <typename ParseContext>
@@ -130,7 +406,7 @@ template <typename Char> struct formatter<std::tm, Char> {
     if (it != ctx.end() && *it == ':') ++it;
     auto end = it;
     while (end != ctx.end() && *end != '}') ++end;
-    tm_format.reserve(internal::to_unsigned(end - it + 1));
+    tm_format.reserve(detail::to_unsigned(end - it + 1));
     tm_format.append(it, end);
     tm_format.push_back('\0');
     return end;
@@ -139,11 +415,10 @@ template <typename Char> struct formatter<std::tm, Char> {
   template <typename FormatContext>
   auto format(const std::tm& tm, FormatContext& ctx) -> decltype(ctx.out()) {
     basic_memory_buffer<Char> buf;
-    std::size_t start = buf.size();
+    size_t start = buf.size();
     for (;;) {
-      std::size_t size = buf.capacity() - start;
-      std::size_t count =
-          internal::strftime(&buf[start], size, &tm_format[0], &tm);
+      size_t size = buf.capacity() - start;
+      size_t count = detail::strftime(&buf[start], size, &tm_format[0], &tm);
       if (count != 0) {
         buf.resize(start + count);
         break;
@@ -155,7 +430,7 @@ template <typename Char> struct formatter<std::tm, Char> {
         // https://github.com/fmtlib/fmt/issues/367
         break;
       }
-      const std::size_t MIN_GROWTH = 10;
+      const size_t MIN_GROWTH = 10;
       buf.reserve(buf.capacity() + (size > MIN_GROWTH ? size : MIN_GROWTH));
     }
     return std::copy(buf.begin(), buf.end(), ctx.out());
@@ -164,7 +439,7 @@ template <typename Char> struct formatter<std::tm, Char> {
   basic_memory_buffer<Char> tm_format;
 };
 
-namespace internal {
+namespace detail {
 template <typename Period> FMT_CONSTEXPR const char* get_units() {
   return nullptr;
 }
@@ -220,12 +495,12 @@ FMT_CONSTEXPR const Char* parse_chrono_format(const Char* begin,
       handler.on_text(ptr - 1, ptr);
       break;
     case 'n': {
-      const char newline[] = "\n";
+      const Char newline[] = {'\n'};
       handler.on_text(newline, newline + 1);
       break;
     }
     case 't': {
-      const char tab[] = "\t";
+      const Char tab[] = {'\t'};
       handler.on_text(tab, tab + 1);
       break;
     }
@@ -421,7 +696,7 @@ inline int to_nonnegative_int(T value, int upper) {
 
 template <typename T, FMT_ENABLE_IF(std::is_integral<T>::value)>
 inline T mod(T x, int y) {
-  return x % y;
+  return x % static_cast<T>(y);
 }
 template <typename T, FMT_ENABLE_IF(std::is_floating_point<T>::value)>
 inline T mod(T x, int y) {
@@ -484,18 +759,36 @@ inline std::chrono::duration<Rep, std::milli> get_milliseconds(
   return std::chrono::duration<Rep, std::milli>(static_cast<Rep>(ms));
 }
 
-template <typename Rep, typename OutputIt>
-OutputIt format_chrono_duration_value(OutputIt out, Rep val, int precision) {
-  if (precision >= 0) return format_to(out, "{:.{}f}", val, precision);
-  return format_to(out, std::is_floating_point<Rep>::value ? "{:g}" : "{}",
+template <typename Char, typename Rep, typename OutputIt>
+OutputIt format_duration_value(OutputIt out, Rep val, int precision) {
+  const Char pr_f[] = {'{', ':', '.', '{', '}', 'f', '}', 0};
+  if (precision >= 0) return format_to(out, pr_f, val, precision);
+  const Char fp_f[] = {'{', ':', 'g', '}', 0};
+  const Char format[] = {'{', '}', 0};
+  return format_to(out, std::is_floating_point<Rep>::value ? fp_f : format,
                    val);
 }
+template <typename Char, typename OutputIt>
+OutputIt copy_unit(string_view unit, OutputIt out, Char) {
+  return std::copy(unit.begin(), unit.end(), out);
+}
 
-template <typename Period, typename OutputIt>
-static OutputIt format_chrono_duration_unit(OutputIt out) {
-  if (const char* unit = get_units<Period>()) return format_to(out, "{}", unit);
-  if (Period::den == 1) return format_to(out, "[{}]s", Period::num);
-  return format_to(out, "[{}/{}]s", Period::num, Period::den);
+template <typename OutputIt>
+OutputIt copy_unit(string_view unit, OutputIt out, wchar_t) {
+  // This works when wchar_t is UTF-32 because units only contain characters
+  // that have the same representation in UTF-16 and UTF-32.
+  utf8_to_utf16 u(unit);
+  return std::copy(u.c_str(), u.c_str() + u.size(), out);
+}
+
+template <typename Char, typename Period, typename OutputIt>
+OutputIt format_duration_unit(OutputIt out) {
+  if (const char* unit = get_units<Period>())
+    return copy_unit(string_view(unit), out, Char());
+  const Char num_f[] = {'[', '{', '}', ']', 's', 0};
+  if (const_check(Period::den == 1)) return format_to(out, num_f, Period::num);
+  const Char num_def_f[] = {'[', '{', '}', '/', '{', '}', ']', 's', 0};
+  return format_to(out, num_def_f, Period::num, Period::den);
 }
 
 template <typename FormatContext, typename OutputIt, typename Rep,
@@ -518,7 +811,10 @@ struct chrono_formatter {
 
   explicit chrono_formatter(FormatContext& ctx, OutputIt o,
                             std::chrono::duration<Rep, Period> d)
-      : context(ctx), out(o), val(d.count()), negative(false) {
+      : context(ctx),
+        out(o),
+        val(static_cast<rep>(d.count())),
+        negative(false) {
     if (d.count() < 0) {
       val = 0 - val;
       negative = true;
@@ -582,24 +878,24 @@ struct chrono_formatter {
   void write(Rep value, int width) {
     write_sign();
     if (isnan(value)) return write_nan();
-    uint32_or_64_or_128_t<int> n = to_unsigned(
-        to_nonnegative_int(value, max_value<int>()));
-    int num_digits = internal::count_digits(n);
+    uint32_or_64_or_128_t<int> n =
+        to_unsigned(to_nonnegative_int(value, max_value<int>()));
+    int num_digits = detail::count_digits(n);
     if (width > num_digits) out = std::fill_n(out, width - num_digits, '0');
-    out = format_decimal<char_type>(out, n, num_digits);
+    out = format_decimal<char_type>(out, n, num_digits).end;
   }
 
   void write_nan() { std::copy_n("nan", 3, out); }
   void write_pinf() { std::copy_n("inf", 3, out); }
   void write_ninf() { std::copy_n("-inf", 4, out); }
 
-  void format_localized(const tm& time, const char* format) {
+  void format_localized(const tm& time, char format, char modifier = 0) {
     if (isnan(val)) return write_nan();
     auto locale = context.locale().template get<std::locale>();
     auto& facet = std::use_facet<std::time_put<char_type>>(locale);
     std::basic_ostringstream<char_type> os;
     os.imbue(locale);
-    facet.put(os, os, ' ', &time, format, format + std::strlen(format));
+    facet.put(os, os, ' ', &time, format, modifier);
     auto str = os.str();
     std::copy(str.begin(), str.end(), out);
   }
@@ -629,7 +925,7 @@ struct chrono_formatter {
     if (ns == numeric_system::standard) return write(hour(), 2);
     auto time = tm();
     time.tm_hour = to_nonnegative_int(hour(), 24);
-    format_localized(time, "%OH");
+    format_localized(time, 'H', 'O');
   }
 
   void on_12_hour(numeric_system ns) {
@@ -638,7 +934,7 @@ struct chrono_formatter {
     if (ns == numeric_system::standard) return write(hour12(), 2);
     auto time = tm();
     time.tm_hour = to_nonnegative_int(hour12(), 12);
-    format_localized(time, "%OI");
+    format_localized(time, 'I', 'O');
   }
 
   void on_minute(numeric_system ns) {
@@ -647,7 +943,7 @@ struct chrono_formatter {
     if (ns == numeric_system::standard) return write(minute(), 2);
     auto time = tm();
     time.tm_min = to_nonnegative_int(minute(), 60);
-    format_localized(time, "%OM");
+    format_localized(time, 'M', 'O');
   }
 
   void on_second(numeric_system ns) {
@@ -672,13 +968,12 @@ struct chrono_formatter {
     }
     auto time = tm();
     time.tm_sec = to_nonnegative_int(second(), 60);
-    format_localized(time, "%OS");
+    format_localized(time, 'S', 'O');
   }
 
   void on_12_hour_time() {
     if (handle_nan_inf()) return;
-
-    format_localized(time(), "%r");
+    format_localized(time(), 'r');
   }
 
   void on_24_hour_time() {
@@ -702,25 +997,27 @@ struct chrono_formatter {
 
   void on_am_pm() {
     if (handle_nan_inf()) return;
-    format_localized(time(), "%p");
+    format_localized(time(), 'p');
   }
 
   void on_duration_value() {
     if (handle_nan_inf()) return;
     write_sign();
-    out = format_chrono_duration_value(out, val, precision);
+    out = format_duration_value<char_type>(out, val, precision);
   }
 
-  void on_duration_unit() { out = format_chrono_duration_unit<Period>(out); }
+  void on_duration_unit() {
+    out = format_duration_unit<char_type, Period>(out);
+  }
 };
-}  // namespace internal
+}  // namespace detail
 
 template <typename Rep, typename Period, typename Char>
 struct formatter<std::chrono::duration<Rep, Period>, Char> {
  private:
   basic_format_specs<Char> specs;
   int precision;
-  using arg_ref_type = internal::arg_ref<Char>;
+  using arg_ref_type = detail::arg_ref<Char>;
   arg_ref_type width_ref;
   arg_ref_type precision_ref;
   mutable basic_string_view<Char> format_str;
@@ -728,7 +1025,7 @@ struct formatter<std::chrono::duration<Rep, Period>, Char> {
 
   struct spec_handler {
     formatter& f;
-    basic_parse_context<Char>& context;
+    basic_format_parse_context<Char>& context;
     basic_string_view<Char> format_str;
 
     template <typename Id> FMT_CONSTEXPR arg_ref_type make_arg_ref(Id arg_id) {
@@ -741,15 +1038,15 @@ struct formatter<std::chrono::duration<Rep, Period>, Char> {
       return arg_ref_type(arg_id);
     }
 
-    FMT_CONSTEXPR arg_ref_type make_arg_ref(internal::auto_id) {
+    FMT_CONSTEXPR arg_ref_type make_arg_ref(detail::auto_id) {
       return arg_ref_type(context.next_arg_id());
     }
 
     void on_error(const char* msg) { FMT_THROW(format_error(msg)); }
-    void on_fill(Char fill) { f.specs.fill[0] = fill; }
+    void on_fill(basic_string_view<Char> fill) { f.specs.fill = fill; }
     void on_align(align_t align) { f.specs.align = align; }
-    void on_width(unsigned width) { f.specs.width = width; }
-    void on_precision(unsigned _precision) { f.precision = _precision; }
+    void on_width(int width) { f.specs.width = width; }
+    void on_precision(int _precision) { f.precision = _precision; }
     void end_precision() {}
 
     template <typename Id> void on_dynamic_width(Id arg_id) {
@@ -761,38 +1058,38 @@ struct formatter<std::chrono::duration<Rep, Period>, Char> {
     }
   };
 
-  using iterator = typename basic_parse_context<Char>::iterator;
+  using iterator = typename basic_format_parse_context<Char>::iterator;
   struct parse_range {
     iterator begin;
     iterator end;
   };
 
-  FMT_CONSTEXPR parse_range do_parse(basic_parse_context<Char>& ctx) {
+  FMT_CONSTEXPR parse_range do_parse(basic_format_parse_context<Char>& ctx) {
     auto begin = ctx.begin(), end = ctx.end();
     if (begin == end || *begin == '}') return {begin, begin};
     spec_handler handler{*this, ctx, format_str};
-    begin = internal::parse_align(begin, end, handler);
+    begin = detail::parse_align(begin, end, handler);
     if (begin == end) return {begin, begin};
-    begin = internal::parse_width(begin, end, handler);
+    begin = detail::parse_width(begin, end, handler);
     if (begin == end) return {begin, begin};
     if (*begin == '.') {
       if (std::is_floating_point<Rep>::value)
-        begin = internal::parse_precision(begin, end, handler);
+        begin = detail::parse_precision(begin, end, handler);
       else
         handler.on_error("precision not allowed for this argument type");
     }
-    end = parse_chrono_format(begin, end, internal::chrono_format_checker());
+    end = parse_chrono_format(begin, end, detail::chrono_format_checker());
     return {begin, end};
   }
 
  public:
   formatter() : precision(-1) {}
 
-  FMT_CONSTEXPR auto parse(basic_parse_context<Char>& ctx)
+  FMT_CONSTEXPR auto parse(basic_format_parse_context<Char>& ctx)
       -> decltype(ctx.begin()) {
     auto range = do_parse(ctx);
     format_str = basic_string_view<Char>(
-        &*range.begin, internal::to_unsigned(range.end - range.begin));
+        &*range.begin, detail::to_unsigned(range.end - range.begin));
     return range.end;
   }
 
@@ -803,23 +1100,21 @@ struct formatter<std::chrono::duration<Rep, Period>, Char> {
     // is not specified.
     basic_memory_buffer<Char> buf;
     auto out = std::back_inserter(buf);
-    using range = internal::output_range<decltype(ctx.out()), Char>;
-    internal::basic_writer<range> w(range(ctx.out()));
-    internal::handle_dynamic_spec<internal::width_checker>(specs.width,
-                                                           width_ref, ctx);
-    internal::handle_dynamic_spec<internal::precision_checker>(
-        precision, precision_ref, ctx);
+    detail::handle_dynamic_spec<detail::width_checker>(specs.width, width_ref,
+                                                       ctx);
+    detail::handle_dynamic_spec<detail::precision_checker>(precision,
+                                                           precision_ref, ctx);
     if (begin == end || *begin == '}') {
-      out = internal::format_chrono_duration_value(out, d.count(), precision);
-      internal::format_chrono_duration_unit<Period>(out);
+      out = detail::format_duration_value<Char>(out, d.count(), precision);
+      detail::format_duration_unit<Char, Period>(out);
     } else {
-      internal::chrono_formatter<FormatContext, decltype(out), Rep, Period> f(
+      detail::chrono_formatter<FormatContext, decltype(out), Rep, Period> f(
           ctx, out, d);
       f.precision = precision;
       parse_chrono_format(begin, end, f);
     }
-    w.write(buf.data(), buf.size(), specs);
-    return w.out();
+    return detail::write(
+        ctx.out(), basic_string_view<Char>(buf.data(), buf.size()), specs);
   }
 };
 

include/fmt/color.h

@@ -198,7 +198,7 @@ struct rgb {
   uint8_t b;
 };
 
-namespace internal {
+namespace detail {
 
 // color is a struct of either a rgb color or a terminal color.
 struct color_type {
@@ -221,7 +221,7 @@ struct color_type {
     uint32_t rgb_color;
   } value;
 };
-}  // namespace internal
+}  // namespace detail
 
 // Experimental text formatting support.
 class text_style {
@@ -298,22 +298,22 @@ class text_style {
   FMT_CONSTEXPR bool has_emphasis() const FMT_NOEXCEPT {
     return static_cast<uint8_t>(ems) != 0;
   }
-  FMT_CONSTEXPR internal::color_type get_foreground() const FMT_NOEXCEPT {
-    assert(has_foreground() && "no foreground specified for this style");
+  FMT_CONSTEXPR detail::color_type get_foreground() const FMT_NOEXCEPT {
+    FMT_ASSERT(has_foreground(), "no foreground specified for this style");
     return foreground_color;
   }
-  FMT_CONSTEXPR internal::color_type get_background() const FMT_NOEXCEPT {
-    assert(has_background() && "no background specified for this style");
+  FMT_CONSTEXPR detail::color_type get_background() const FMT_NOEXCEPT {
+    FMT_ASSERT(has_background(), "no background specified for this style");
     return background_color;
   }
   FMT_CONSTEXPR emphasis get_emphasis() const FMT_NOEXCEPT {
-    assert(has_emphasis() && "no emphasis specified for this style");
+    FMT_ASSERT(has_emphasis(), "no emphasis specified for this style");
     return ems;
   }
 
  private:
   FMT_CONSTEXPR text_style(bool is_foreground,
-                           internal::color_type text_color) FMT_NOEXCEPT
+                           detail::color_type text_color) FMT_NOEXCEPT
       : set_foreground_color(),
         set_background_color(),
         ems() {
@@ -326,23 +326,23 @@ class text_style {
     }
   }
 
-  friend FMT_CONSTEXPR_DECL text_style fg(internal::color_type foreground)
+  friend FMT_CONSTEXPR_DECL text_style fg(detail::color_type foreground)
       FMT_NOEXCEPT;
-  friend FMT_CONSTEXPR_DECL text_style bg(internal::color_type background)
+  friend FMT_CONSTEXPR_DECL text_style bg(detail::color_type background)
       FMT_NOEXCEPT;
 
-  internal::color_type foreground_color;
-  internal::color_type background_color;
+  detail::color_type foreground_color;
+  detail::color_type background_color;
   bool set_foreground_color;
   bool set_background_color;
   emphasis ems;
 };
 
-FMT_CONSTEXPR text_style fg(internal::color_type foreground) FMT_NOEXCEPT {
+FMT_CONSTEXPR text_style fg(detail::color_type foreground) FMT_NOEXCEPT {
   return text_style(/*is_foreground=*/true, foreground);
 }
 
-FMT_CONSTEXPR text_style bg(internal::color_type background) FMT_NOEXCEPT {
+FMT_CONSTEXPR text_style bg(detail::color_type background) FMT_NOEXCEPT {
   return text_style(/*is_foreground=*/false, background);
 }
 
@@ -350,21 +350,21 @@ FMT_CONSTEXPR text_style operator|(emphasis lhs, emphasis rhs) FMT_NOEXCEPT {
   return text_style(lhs) | rhs;
 }
 
-namespace internal {
+namespace detail {
 
 template <typename Char> struct ansi_color_escape {
-  FMT_CONSTEXPR ansi_color_escape(internal::color_type text_color,
+  FMT_CONSTEXPR ansi_color_escape(detail::color_type text_color,
                                   const char* esc) FMT_NOEXCEPT {
     // If we have a terminal color, we need to output another escape code
     // sequence.
     if (!text_color.is_rgb) {
-      bool is_background = esc == internal::data::background_color;
+      bool is_background = esc == detail::data::background_color;
       uint32_t value = text_color.value.term_color;
       // Background ASCII codes are the same as the foreground ones but with
       // 10 more.
       if (is_background) value += 10u;
 
-      std::size_t index = 0;
+      size_t index = 0;
       buffer[index++] = static_cast<Char>('\x1b');
       buffer[index++] = static_cast<Char>('[');
 
@@ -398,7 +398,7 @@ template <typename Char> struct ansi_color_escape {
     if (em_bits & static_cast<uint8_t>(emphasis::strikethrough))
       em_codes[3] = 9;
 
-    std::size_t index = 0;
+    size_t index = 0;
     for (int i = 0; i < 4; ++i) {
       if (!em_codes[i]) continue;
       buffer[index++] = static_cast<Char>('\x1b');
@@ -412,7 +412,7 @@ template <typename Char> struct ansi_color_escape {
 
   FMT_CONSTEXPR const Char* begin() const FMT_NOEXCEPT { return buffer; }
   FMT_CONSTEXPR const Char* end() const FMT_NOEXCEPT {
-    return buffer + std::strlen(buffer);
+    return buffer + std::char_traits<Char>::length(buffer);
   }
 
  private:
@@ -429,14 +429,14 @@ template <typename Char> struct ansi_color_escape {
 
 template <typename Char>
 FMT_CONSTEXPR ansi_color_escape<Char> make_foreground_color(
-    internal::color_type foreground) FMT_NOEXCEPT {
-  return ansi_color_escape<Char>(foreground, internal::data::foreground_color);
+    detail::color_type foreground) FMT_NOEXCEPT {
+  return ansi_color_escape<Char>(foreground, detail::data::foreground_color);
 }
 
 template <typename Char>
 FMT_CONSTEXPR ansi_color_escape<Char> make_background_color(
-    internal::color_type background) FMT_NOEXCEPT {
-  return ansi_color_escape<Char>(background, internal::data::background_color);
+    detail::color_type background) FMT_NOEXCEPT {
+  return ansi_color_escape<Char>(background, detail::data::background_color);
 }
 
 template <typename Char>
@@ -455,11 +455,11 @@ inline void fputs<wchar_t>(const wchar_t* chars, FILE* stream) FMT_NOEXCEPT {
 }
 
 template <typename Char> inline void reset_color(FILE* stream) FMT_NOEXCEPT {
-  fputs(internal::data::reset_color, stream);
+  fputs(detail::data::reset_color, stream);
 }
 
 template <> inline void reset_color<wchar_t>(FILE* stream) FMT_NOEXCEPT {
-  fputs(internal::data::wreset_color, stream);
+  fputs(detail::data::wreset_color, stream);
 }
 
 template <typename Char>
@@ -470,58 +470,37 @@ inline void reset_color(basic_memory_buffer<Char>& buffer) FMT_NOEXCEPT {
 }
 
 template <typename Char>
-std::basic_string<Char> vformat(const text_style& ts,
-                                basic_string_view<Char> format_str,
-                                basic_format_args<buffer_context<Char> > args) {
-  basic_memory_buffer<Char> buffer;
+void vformat_to(basic_memory_buffer<Char>& buf, const text_style& ts,
+                basic_string_view<Char> format_str,
+                basic_format_args<buffer_context<Char>> args) {
   bool has_style = false;
   if (ts.has_emphasis()) {
     has_style = true;
-    ansi_color_escape<Char> escape = make_emphasis<Char>(ts.get_emphasis());
-    buffer.append(escape.begin(), escape.end());
+    auto emphasis = detail::make_emphasis<Char>(ts.get_emphasis());
+    buf.append(emphasis.begin(), emphasis.end());
   }
   if (ts.has_foreground()) {
     has_style = true;
-    ansi_color_escape<Char> escape =
-        make_foreground_color<Char>(ts.get_foreground());
-    buffer.append(escape.begin(), escape.end());
+    auto foreground = detail::make_foreground_color<Char>(ts.get_foreground());
+    buf.append(foreground.begin(), foreground.end());
   }
   if (ts.has_background()) {
     has_style = true;
-    ansi_color_escape<Char> escape =
-        make_background_color<Char>(ts.get_background());
-    buffer.append(escape.begin(), escape.end());
+    auto background = detail::make_background_color<Char>(ts.get_background());
+    buf.append(background.begin(), background.end());
   }
-  internal::vformat_to(buffer, format_str, args);
-  if (has_style) {
-    reset_color<Char>(buffer);
-  }
-  return fmt::to_string(buffer);
+  detail::vformat_to(buf, format_str, args);
+  if (has_style) detail::reset_color<Char>(buf);
 }
-}  // namespace internal
+}  // namespace detail
 
-template <typename S, typename Char = char_t<S> >
+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) {
-  bool has_style = false;
-  if (ts.has_emphasis()) {
-    has_style = true;
-    internal::fputs<Char>(internal::make_emphasis<Char>(ts.get_emphasis()), f);
-  }
-  if (ts.has_foreground()) {
-    has_style = true;
-    internal::fputs<Char>(
-        internal::make_foreground_color<Char>(ts.get_foreground()), f);
-  }
-  if (ts.has_background()) {
-    has_style = true;
-    internal::fputs<Char>(
-        internal::make_background_color<Char>(ts.get_background()), f);
-  }
-  vprint(f, format, args);
-  if (has_style) {
-    internal::reset_color<Char>(f);
-  }
+            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);
 }
 
 /**
@@ -532,11 +511,11 @@ void vprint(std::FILE* f, const text_style& ts, const S& format,
                "Elapsed time: {0:.2f} seconds", 1.23);
  */
 template <typename S, typename... Args,
-          FMT_ENABLE_IF(internal::is_string<S>::value)>
+          FMT_ENABLE_IF(detail::is_string<S>::value)>
 void print(std::FILE* f, const text_style& ts, const S& format_str,
            const Args&... args) {
-  internal::check_format_string<Args...>(format_str);
-  using context = buffer_context<char_t<S> >;
+  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));
 }
@@ -549,16 +528,18 @@ void print(std::FILE* f, const text_style& ts, const S& format_str,
                "Elapsed time: {0:.2f} seconds", 1.23);
  */
 template <typename S, typename... Args,
-          FMT_ENABLE_IF(internal::is_string<S>::value)>
+          FMT_ENABLE_IF(detail::is_string<S>::value)>
 void print(const text_style& ts, const S& format_str, const Args&... args) {
   return print(stdout, ts, format_str, args...);
 }
 
-template <typename S, typename Char = char_t<S> >
+template <typename S, typename Char = char_t<S>>
 inline std::basic_string<Char> vformat(
     const text_style& ts, const S& format_str,
-    basic_format_args<buffer_context<Char> > args) {
-  return internal::vformat(ts, to_string_view(format_str), args);
+    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);
+  return fmt::to_string(buf);
 }
 
 /**
@@ -573,12 +554,11 @@ inline std::basic_string<Char> vformat(
                                       "The answer is {}", 42);
   \endrst
 */
-template <typename S, typename... Args, typename Char = char_t<S> >
+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 internal::vformat(
-      ts, to_string_view(format_str),
-      {internal::make_args_checked<Args...>(format_str, args...)});
+  return vformat(ts, to_string_view(format_str),
+                 detail::make_args_checked<Args...>(format_str, args...));
 }
 
 FMT_END_NAMESPACE

include/fmt/compile.h

@@ -9,10 +9,37 @@
 #define FMT_COMPILE_H_
 
 #include <vector>
+
 #include "format.h"
 
 FMT_BEGIN_NAMESPACE
-namespace internal {
+namespace detail {
+
+// A compile-time string which is compiled into fast formatting code.
+class compiled_string {};
+
+template <typename S>
+struct is_compiled_string : std::is_base_of<compiled_string, S> {};
+
+/**
+  \rst
+  Converts a string literal *s* into a format string that will be parsed at
+  compile time and converted into efficient formatting code. Requires C++17
+  ``constexpr if`` compiler support.
+
+  **Example**::
+
+    // Converts 42 into std::string using the most efficient method and no
+    // runtime format string processing.
+    std::string s = fmt::format(FMT_COMPILE("{}"), 42);
+  \endrst
+ */
+#define FMT_COMPILE(s) FMT_STRING_IMPL(s, fmt::detail::compiled_string)
+
+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.
@@ -26,11 +53,11 @@ template <typename Char> struct format_part {
 
   kind part_kind;
   union value {
-    unsigned arg_index;
+    int arg_index;
     basic_string_view<Char> str;
     replacement repl;
 
-    FMT_CONSTEXPR value(unsigned index = 0) : arg_index(index) {}
+    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;
@@ -40,7 +67,7 @@ template <typename Char> struct format_part {
   FMT_CONSTEXPR format_part(kind k = kind::arg_index, value v = {})
       : part_kind(k), val(v) {}
 
-  static FMT_CONSTEXPR format_part make_arg_index(unsigned index) {
+  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) {
@@ -61,13 +88,15 @@ template <typename Char> struct part_counter {
     if (begin != end) ++num_parts;
   }
 
-  FMT_CONSTEXPR void on_arg_id() { ++num_parts; }
-  FMT_CONSTEXPR void on_arg_id(unsigned) { ++num_parts; }
-  FMT_CONSTEXPR void on_arg_id(basic_string_view<Char>) { ++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(const Char*) {}
+  FMT_CONSTEXPR void on_replacement_field(int, const Char*) {}
 
-  FMT_CONSTEXPR const Char* on_format_specs(const Char* begin,
+  FMT_CONSTEXPR const Char* on_format_specs(int, const Char* begin,
                                             const Char* end) {
     // Find the matching brace.
     unsigned brace_counter = 0;
@@ -101,7 +130,7 @@ class format_string_compiler : public error_handler {
   PartHandler handler_;
   part part_;
   basic_string_view<Char> format_str_;
-  basic_parse_context<Char> parse_context_;
+  basic_format_parse_context<Char> parse_context_;
 
  public:
   FMT_CONSTEXPR format_string_compiler(basic_string_view<Char> format_str,
@@ -115,29 +144,32 @@ class format_string_compiler : public error_handler {
       handler_(part::make_text({begin, to_unsigned(end - begin)}));
   }
 
-  FMT_CONSTEXPR void on_arg_id() {
+  FMT_CONSTEXPR int on_arg_id() {
     part_ = part::make_arg_index(parse_context_.next_arg_id());
+    return 0;
   }
 
-  FMT_CONSTEXPR void on_arg_id(unsigned id) {
+  FMT_CONSTEXPR int on_arg_id(int id) {
     parse_context_.check_arg_id(id);
     part_ = part::make_arg_index(id);
+    return 0;
   }
 
-  FMT_CONSTEXPR void on_arg_id(basic_string_view<Char> id) {
+  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(const Char* ptr) {
+  FMT_CONSTEXPR void on_replacement_field(int, const Char* ptr) {
     part_.arg_id_end = ptr;
     handler_(part_);
   }
 
-  FMT_CONSTEXPR const Char* on_format_specs(const Char* begin,
+  FMT_CONSTEXPR const Char* on_format_specs(int, const Char* begin,
                                             const Char* end) {
     auto repl = typename part::replacement();
-    dynamic_specs_handler<basic_parse_context<Char>> handler(repl.specs,
-                                                             parse_context_);
+    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
@@ -159,21 +191,24 @@ FMT_CONSTEXPR void compile_format_string(basic_string_view<Char> format_str,
       format_string_compiler<Char, PartHandler>(format_str, handler));
 }
 
-template <typename Range, typename Context, typename Id>
-void format_arg(basic_parse_context<typename Range::value_type>& parse_ctx,
-                Context& ctx, Id arg_id) {
-  ctx.advance_to(
-      visit_format_arg(arg_formatter<Range>(ctx, &parse_ctx), ctx.arg(arg_id)));
+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 Range, typename CompiledFormat>
-auto vformat_to(Range out, CompiledFormat& cf, basic_format_args<Context> args)
-    -> typename Context::iterator {
+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_parse_context<char_type> parse_ctx(to_string_view(cf.format_str_));
-  Context ctx(out.begin(), args);
+  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);
@@ -194,12 +229,12 @@ auto vformat_to(Range out, CompiledFormat& cf, basic_format_args<Context> args)
 
     case format_part_t::kind::arg_index:
       advance_to(parse_ctx, part.arg_id_end);
-      internal::format_arg<Range>(parse_ctx, ctx, value.arg_index);
+      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);
-      internal::format_arg<Range>(parse_ctx, ctx, value.str);
+      detail::format_arg<OutputIt>(parse_ctx, ctx, value.str);
       break;
 
     case format_part_t::kind::replacement: {
@@ -223,7 +258,9 @@ auto vformat_to(Range out, CompiledFormat& cf, basic_format_args<Context> args)
 
       advance_to(parse_ctx, part.arg_id_end);
       ctx.advance_to(
-          visit_format_arg(arg_formatter<Range>(ctx, nullptr, &specs), arg));
+          visit_format_arg(arg_formatter<OutputIt, typename Context::char_type>(
+                               ctx, nullptr, &specs),
+                           arg));
       break;
     }
     }
@@ -237,7 +274,7 @@ 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<internal::format_part<char_type>>;
+  using parts_container = std::vector<detail::format_part<char_type>>;
 
   parts_container compiled_parts;
 
@@ -302,7 +339,7 @@ struct compiled_format_base<S, enable_if_t<is_compile_string<S>::value>>
   const parts_container& parts() const {
     static FMT_CONSTEXPR_DECL const auto compiled_parts =
         compile_to_parts<char_type, num_format_parts>(
-            internal::to_string_view(S()));
+            detail::to_string_view(S()));
     return compiled_parts.data;
   }
 };
@@ -315,8 +352,8 @@ class compiled_format : private compiled_format_base<S> {
  private:
   basic_string_view<char_type> format_str_;
 
-  template <typename Context, typename Range, typename CompiledFormat>
-  friend auto cf::vformat_to(Range out, CompiledFormat& cf,
+  template <typename Context, typename OutputIt, typename CompiledFormat>
+  friend auto cf::vformat_to(OutputIt out, CompiledFormat& cf,
                              basic_format_args<Context> args) ->
       typename Context::iterator;
 
@@ -348,43 +385,27 @@ template <int N, typename... Args> struct get_type_impl<N, type_list<Args...>> {
 template <int N, typename T>
 using get_type = typename get_type_impl<N, T>::type;
 
+template <typename T> struct is_compiled_format : std::false_type {};
+
 template <typename Char> struct text {
   basic_string_view<Char> data;
   using char_type = Char;
 
   template <typename OutputIt, typename... Args>
   OutputIt format(OutputIt out, const Args&...) const {
-    // TODO: reserve
-    return copy_str<Char>(data.begin(), data.end(), out);
+    return write<Char>(out, data);
   }
 };
 
+template <typename Char>
+struct is_compiled_format<text<Char>> : std::true_type {};
+
 template <typename Char>
 constexpr text<Char> make_text(basic_string_view<Char> s, size_t pos,
                                size_t size) {
   return {{&s[pos], size}};
 }
 
-template <typename Char, typename OutputIt, typename T,
-          std::enable_if_t<std::is_integral_v<T>, int> = 0>
-OutputIt format_default(OutputIt out, T value) {
-  // TODO: reserve
-  format_int fi(value);
-  return std::copy(fi.data(), fi.data() + fi.size(), out);
-}
-
-template <typename Char, typename OutputIt>
-OutputIt format_default(OutputIt out, Char value) {
-  *out++ = value;
-  return out;
-}
-
-template <typename Char, typename OutputIt>
-OutputIt format_default(OutputIt out, const Char* value) {
-  auto length = std::char_traits<Char>::length(value);
-  return copy_str<Char>(value, value + length, out);
-}
-
 // A replacement field that refers to argument N.
 template <typename Char, typename T, int N> struct field {
   using char_type = Char;
@@ -393,10 +414,30 @@ template <typename Char, typename T, int N> struct field {
   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...);
-    return format_default<Char>(out, arg);
+    return write<Char>(out, arg);
   }
 };
 
+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 N and has format specifiers.
+template <typename Char, typename T, int N> struct spec_field {
+  using char_type = Char;
+  mutable 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);
+  }
+};
+
+template <typename Char, typename T, int N>
+struct is_compiled_format<spec_field<Char, T, N>> : std::true_type {};
+
 template <typename L, typename R> struct concat {
   L lhs;
   R rhs;
@@ -409,6 +450,9 @@ template <typename L, typename R> struct concat {
   }
 };
 
+template <typename L, typename R>
+struct is_compiled_format<concat<L, R>> : std::true_type {};
+
 template <typename L, typename R>
 constexpr concat<L, R> make_concat(L lhs, R rhs) {
   return {lhs, rhs};
@@ -429,7 +473,8 @@ constexpr auto compile_format_string(S format_str);
 
 template <typename Args, size_t POS, int ID, typename T, typename S>
 constexpr auto parse_tail(T head, S format_str) {
-  if constexpr (POS != to_string_view(format_str).size()) {
+  if constexpr (POS !=
+                basic_string_view<typename S::char_type>(format_str).size()) {
     constexpr auto tail = compile_format_string<Args, POS, ID>(format_str);
     if constexpr (std::is_same<remove_cvref_t<decltype(tail)>,
                                unknown_format>())
@@ -441,6 +486,21 @@ 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;
+};
+
+template <typename T, typename Char>
+constexpr parse_specs_result<T, Char> parse_specs(basic_string_view<Char> str,
+                                                  size_t pos) {
+  str.remove_prefix(pos);
+  auto ctx = basic_format_parse_context<Char>(str);
+  auto f = formatter<T, Char>();
+  auto end = f.parse(ctx);
+  return {f, pos + (end - str.data()) + 1};
+}
+
 // Compiles a non-empty format string and returns the compiled representation
 // or unknown_format() on unrecognized input.
 template <typename Args, size_t POS, int ID, typename S>
@@ -454,12 +514,13 @@ constexpr auto compile_format_string(S format_str) {
       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>;
-      if constexpr (std::is_same<type, int>::value) {
-        return parse_tail<Args, POS + 2, ID + 1>(field<char_type, type, ID>(),
-                                                 format_str);
-      } else {
-        return unknown_format();
-      }
+      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 {
       return unknown_format();
     }
@@ -473,107 +534,130 @@ constexpr auto compile_format_string(S format_str) {
                                      format_str);
   }
 }
-#endif  // __cpp_if_constexpr
-}  // namespace internal
 
-#if FMT_USE_CONSTEXPR
-#  ifdef __cpp_if_constexpr
 template <typename... Args, typename S,
-          FMT_ENABLE_IF(is_compile_string<S>::value)>
+          FMT_ENABLE_IF(is_compile_string<S>::value ||
+                        detail::is_compiled_string<S>::value)>
 constexpr auto compile(S format_str) {
   constexpr basic_string_view<typename S::char_type> str = format_str;
   if constexpr (str.size() == 0) {
-    return internal::make_text(str, 0, 0);
+    return detail::make_text(str, 0, 0);
   } else {
     constexpr auto result =
-        internal::compile_format_string<internal::type_list<Args...>, 0, 0>(
+        detail::compile_format_string<detail::type_list<Args...>, 0, 0>(
             format_str);
     if constexpr (std::is_same<remove_cvref_t<decltype(result)>,
-                               internal::unknown_format>()) {
-      return internal::compiled_format<S, Args...>(to_string_view(format_str));
+                               detail::unknown_format>()) {
+      return detail::compiled_format<S, Args...>(to_string_view(format_str));
     } else {
       return result;
     }
   }
 }
-
-template <typename CompiledFormat, typename... Args,
-          typename Char = typename CompiledFormat::char_type,
-          FMT_ENABLE_IF(!std::is_base_of<internal::basic_compiled_format,
-                                         CompiledFormat>::value)>
-std::basic_string<Char> format(const CompiledFormat& cf, const Args&... args) {
-  basic_memory_buffer<Char> buffer;
-  using range = buffer_range<Char>;
-  using context = buffer_context<Char>;
-  cf.format(std::back_inserter(buffer), args...);
-  return to_string(buffer);
-}
-
-template <typename OutputIt, typename CompiledFormat, typename... Args,
-          FMT_ENABLE_IF(!std::is_base_of<internal::basic_compiled_format,
-                                         CompiledFormat>::value)>
-OutputIt format_to(OutputIt out, const CompiledFormat& cf,
-                   const Args&... args) {
-  return cf.format(out, args...);
-}
-#  else
+#else
 template <typename... Args, typename S,
           FMT_ENABLE_IF(is_compile_string<S>::value)>
-constexpr auto compile(S format_str) -> internal::compiled_format<S, Args...> {
-  return internal::compiled_format<S, Args...>(to_string_view(format_str));
+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
-#endif    // FMT_USE_CONSTEXPR
+#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])
-    -> internal::compiled_format<const Char*, Args...> {
-  return internal::compiled_format<const Char*, Args...>(
+    -> detail::compiled_format<const Char*, Args...> {
+  return detail::compiled_format<const Char*, Args...>(
       basic_string_view<Char>(format_str, N - 1));
 }
+}  // 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...);
+}
+
+#if FMT_USE_CONSTEXPR
+#  ifdef __cpp_if_constexpr
 
 template <typename CompiledFormat, typename... Args,
           typename Char = typename CompiledFormat::char_type,
-          FMT_ENABLE_IF(std::is_base_of<internal::basic_compiled_format,
-                                        CompiledFormat>::value)>
-std::basic_string<Char> format(const CompiledFormat& cf, const Args&... args) {
+          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;
-  using range = buffer_range<Char>;
-  using context = buffer_context<Char>;
-  internal::cf::vformat_to<context>(range(buffer), cf,
-                                    {make_format_args<context>(args...)});
+  detail::buffer<Char>& base = buffer;
+  cf.format(std::back_inserter(base), args...);
   return to_string(buffer);
 }
 
 template <typename OutputIt, typename CompiledFormat, typename... Args,
-          FMT_ENABLE_IF(std::is_base_of<internal::basic_compiled_format,
+          FMT_ENABLE_IF(detail::is_compiled_format<CompiledFormat>::value)>
+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...));
+  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 range = internal::output_range<OutputIt, char_type>;
   using context = format_context_t<OutputIt, char_type>;
-  return internal::cf::vformat_to<context>(
-      range(out), cf, {make_format_args<context>(args...)});
+  return detail::cf::vformat_to<context>(out, cf,
+                                         make_format_args<context>(args...));
 }
 
-template <typename OutputIt, typename CompiledFormat, typename... Args,
-          FMT_ENABLE_IF(internal::is_output_iterator<OutputIt>::value)>
+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) {
+  constexpr auto compiled = detail::compile<Args...>(S());
+  return format_to(out, compiled, args...);
+}
+
+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)>
 format_to_n_result<OutputIt> format_to_n(OutputIt out, size_t n,
                                          const CompiledFormat& cf,
                                          const Args&... args) {
   auto it =
-      format_to(internal::truncating_iterator<OutputIt>(out, n), cf, args...);
+      format_to(detail::truncating_iterator<OutputIt>(out, n), cf, args...);
   return {it.base(), it.count()};
 }
 
 template <typename CompiledFormat, typename... Args>
-std::size_t formatted_size(const CompiledFormat& cf, const Args&... args) {
-  return format_to(
-             internal::counting_iterator<typename CompiledFormat::char_type>(),
-             cf, args...)
-      .count();
+size_t formatted_size(const CompiledFormat& cf, const Args&... args) {
+  return format_to(detail::counting_iterator(), cf, args...).count();
 }
 
 FMT_END_NAMESPACE

include/fmt/locale.h

@@ -9,63 +9,64 @@
 #define FMT_LOCALE_H_
 
 #include <locale>
+
 #include "format.h"
 
 FMT_BEGIN_NAMESPACE
 
-namespace internal {
+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<Char>> args) {
-  using range = buffer_range<Char>;
-  return vformat_to<arg_formatter<range>>(buf, to_string_view(format_str), args,
-                                          internal::locale_ref(loc));
+    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<Char>> args) {
+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;
-  internal::vformat_to(loc, buffer, format_str, args);
+  detail::vformat_to(loc, buffer, format_str, args);
   return fmt::to_string(buffer);
 }
-}  // namespace internal
+}  // 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<Char>> args) {
-  return internal::vformat(loc, to_string_view(format_str), args);
+    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 internal::vformat(
+  return detail::vformat(
       loc, to_string_view(format_str),
-      {internal::make_args_checked<Args...>(format_str, args...)});
+      detail::make_args_checked<Args...>(format_str, args...));
 }
 
 template <typename S, typename OutputIt, typename... Args,
           typename Char = enable_if_t<
-              internal::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<OutputIt, Char> args) {
-  using range = internal::output_range<OutputIt, Char>;
-  return vformat_to<arg_formatter<range>>(
-      range(out), to_string_view(format_str), args, internal::locale_ref(loc));
+              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(internal::is_output_iterator<OutputIt>::value&&
-                            internal::is_string<S>::value)>
+          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) {
-  internal::check_format_string<Args...>(format_str);
+  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),

include/fmt/os.h

@@ -0,0 +1,450 @@
+// Formatting library for C++ - optional OS-specific functionality
+//
+// Copyright (c) 2012 - present, Victor Zverovich
+// All rights reserved.
+//
+// For the license information refer to format.h.
+
+#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
+
+#if defined __APPLE__ || defined(__FreeBSD__)
+#  include <xlocale.h>  // for LC_NUMERIC_MASK on OS X
+#endif
+
+#include "format.h"
+
+// 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
+#endif
+
+#ifndef FMT_POSIX
+#  if defined(_WIN32) && !defined(__MINGW32__)
+// Fix warnings about deprecated symbols.
+#    define FMT_POSIX(call) _##call
+#  else
+#    define FMT_POSIX(call) call
+#  endif
+#endif
+
+// Calls to system functions are wrapped in FMT_SYSTEM for testability.
+#ifdef FMT_SYSTEM
+#  define FMT_POSIX_CALL(call) FMT_SYSTEM(call)
+#else
+#  define FMT_SYSTEM(call) ::call
+#  ifdef _WIN32
+// Fix warnings about deprecated symbols.
+#    define FMT_POSIX_CALL(call) ::_##call
+#  else
+#    define FMT_POSIX_CALL(call) ::call
+#  endif
+#endif
+
+// Retries the expression while it evaluates to error_result and errno
+// equals to EINTR.
+#ifndef _WIN32
+#  define FMT_RETRY_VAL(result, expression, error_result) \
+    do {                                                  \
+      (result) = (expression);                            \
+    } while ((result) == (error_result) && errno == EINTR)
+#else
+#  define FMT_RETRY_VAL(result, expression, error_result) result = (expression)
+#endif
+
+#define FMT_RETRY(result, expression) FMT_RETRY_VAL(result, expression, -1)
+
+FMT_BEGIN_NAMESPACE
+
+/**
+  \rst
+  A reference to a null-terminated string. It can be constructed from a C
+  string or ``std::string``.
+
+  You can use one of the following type aliases for common character types:
+
+  +---------------+-----------------------------+
+  | Type          | Definition                  |
+  +===============+=============================+
+  | cstring_view  | basic_cstring_view<char>    |
+  +---------------+-----------------------------+
+  | wcstring_view | basic_cstring_view<wchar_t> |
+  +---------------+-----------------------------+
+
+  This class is most useful as a parameter type to allow passing
+  different types of strings to a function, for example::
+
+    template <typename... Args>
+    std::string format(cstring_view format_str, const Args & ... args);
+
+    format("{}", 42);
+    format(std::string("{}"), 42);
+  \endrst
+ */
+template <typename Char> class basic_cstring_view {
+ private:
+  const Char* data_;
+
+ public:
+  /** Constructs a string reference object from a C string. */
+  basic_cstring_view(const Char* s) : data_(s) {}
+
+  /**
+    \rst
+    Constructs a string reference from an ``std::string`` object.
+    \endrst
+   */
+  basic_cstring_view(const std::basic_string<Char>& s) : data_(s.c_str()) {}
+
+  /** Returns the pointer to a C string. */
+  const Char* c_str() const { return data_; }
+};
+
+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
+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
+
+/** A Windows error. */
+class windows_error : public system_error {
+ private:
+  FMT_API void init(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
+
+   .. 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".
+
+   **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...));
+  }
+};
+
+// 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;
+#endif  // _WIN32
+
+// A buffered file.
+class buffered_file {
+ private:
+  FILE* file_;
+
+  friend class file;
+
+  explicit buffered_file(FILE* f) : file_(f) {}
+
+ public:
+  buffered_file(const buffered_file&) = delete;
+  void operator=(const buffered_file&) = delete;
+
+  // Constructs a buffered_file object which doesn't represent any file.
+  buffered_file() FMT_NOEXCEPT : file_(nullptr) {}
+
+  // Destroys the object closing the file it represents if any.
+  FMT_API ~buffered_file() FMT_NOEXCEPT;
+
+ public:
+  buffered_file(buffered_file&& other) FMT_NOEXCEPT : file_(other.file_) {
+    other.file_ = nullptr;
+  }
+
+  buffered_file& operator=(buffered_file&& other) {
+    close();
+    file_ = other.file_;
+    other.file_ = nullptr;
+    return *this;
+  }
+
+  // Opens a file.
+  FMT_API buffered_file(cstring_view filename, cstring_view mode);
+
+  // Closes the file.
+  FMT_API void close();
+
+  // Returns the pointer to a FILE object representing this file.
+  FILE* get() const FMT_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;
+
+  void vprint(string_view format_str, format_args args) {
+    fmt::vprint(file_, format_str, args);
+  }
+
+  template <typename... Args>
+  inline void print(string_view format_str, const Args&... args) {
+    vprint(format_str, 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
+// 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 {
+ private:
+  int fd_;  // File descriptor.
+
+  // Constructs a file object with a given descriptor.
+  explicit file(int fd) : fd_(fd) {}
+
+ public:
+  // Possible values for the oflag argument to the constructor.
+  enum {
+    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.
+  };
+
+  // Constructs a file object which doesn't represent any file.
+  file() FMT_NOEXCEPT : fd_(-1) {}
+
+  // Opens a file and constructs a file object representing this file.
+  FMT_API 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& operator=(file&& other) FMT_NOEXCEPT {
+    close();
+    fd_ = other.fd_;
+    other.fd_ = -1;
+    return *this;
+  }
+
+  // Destroys the object closing the file it represents if any.
+  FMT_API ~file() FMT_NOEXCEPT;
+
+  // Returns the file descriptor.
+  int descriptor() const FMT_NOEXCEPT { return fd_; }
+
+  // Closes the file.
+  FMT_API void close();
+
+  // Returns the file size. The size has signed type for consistency with
+  // stat::st_size.
+  FMT_API 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);
+
+  // Attempts to write count bytes from the specified buffer to the file.
+  FMT_API 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);
+
+  // Makes fd be the copy of this file descriptor, closing fd first if
+  // necessary.
+  FMT_API 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;
+
+  // 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);
+
+  // 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);
+};
+
+// Returns the memory page size.
+long getpagesize();
+
+class direct_buffered_file;
+
+template <typename S, typename... Args>
+void print(direct_buffered_file& f, const S& format_str,
+           const Args&... args);
+
+// A buffered file with a direct buffer access and no synchronization.
+class direct_buffered_file {
+ private:
+  file file_;
+
+  enum { buffer_size = 4096 };
+  char buffer_[buffer_size];
+  int pos_;
+
+  void flush() {
+    if (pos_ == 0) return;
+    file_.write(buffer_, pos_);
+    pos_ = 0;
+  }
+
+  int free_capacity() const { return buffer_size - pos_; }
+
+ public:
+  direct_buffered_file(cstring_view path, int oflag)
+    : file_(path, oflag), pos_(0) {}
+
+  ~direct_buffered_file() {
+    flush();
+  }
+
+  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 {
+ private:
+#  ifdef _WIN32
+  using locale_t = _locale_t;
+
+  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_;
+
+ public:
+  using type = locale_t;
+  locale(const locale&) = delete;
+  void operator=(const locale&) = delete;
+
+  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_); }
+
+  type get() const { return locale_; }
+
+  // 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;
+  }
+};
+using Locale FMT_DEPRECATED_ALIAS = locale;
+#endif  // FMT_LOCALE
+FMT_END_NAMESPACE
+
+#endif  // FMT_OS_H_

include/fmt/ostream.h

@@ -9,10 +9,15 @@
 #define FMT_OSTREAM_H_
 
 #include <ostream>
+
 #include "format.h"
 
 FMT_BEGIN_NAMESPACE
-namespace internal {
+
+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:
@@ -75,7 +80,7 @@ template <typename T, typename Char> class is_streamable {
 
 // Write the content of buf to os.
 template <typename Char>
-void write(std::basic_ostream<Char>& os, buffer<Char>& buf) {
+void write_buffer(std::basic_ostream<Char>& os, buffer<Char>& buf) {
   const Char* buf_data = buf.data();
   using unsigned_streamsize = std::make_unsigned<std::streamsize>::type;
   unsigned_streamsize size = buf.size();
@@ -89,34 +94,57 @@ void write(std::basic_ostream<Char>& os, buffer<Char>& buf) {
 }
 
 template <typename Char, typename T>
-void format_value(buffer<Char>& buf, const T& value) {
+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);
-  output.exceptions(std::ios_base::failbit | std::ios_base::badbit);
+#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>>
-    : formatter<basic_string_view<Char>, Char> {
-  template <typename Context>
-  auto format(const T& value, Context& ctx) -> decltype(ctx.out()) {
+    : 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 OutputIt>
+  auto format(const T& value, basic_format_context<OutputIt, Char>& ctx)
+      -> OutputIt {
     basic_memory_buffer<Char> buffer;
-    format_value(buffer, value);
+    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 internal
+}  // namespace detail
 
 template <typename Char>
 void vprint(std::basic_ostream<Char>& os, basic_string_view<Char> format_str,
-            basic_format_args<buffer_context<Char>> args) {
+            basic_format_args<buffer_context<type_identity_t<Char>>> args) {
   basic_memory_buffer<Char> buffer;
-  internal::vformat_to(buffer, format_str, args);
-  internal::write(os, buffer);
+  detail::vformat_to(buffer, format_str, args);
+  detail::write_buffer(os, buffer);
 }
 
 /**
@@ -129,10 +157,10 @@ void vprint(std::basic_ostream<Char>& os, basic_string_view<Char> format_str,
   \endrst
  */
 template <typename S, typename... Args,
-          typename Char = enable_if_t<internal::is_string<S>::value, char_t<S>>>
+          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),
-         {internal::make_args_checked<Args...>(format_str, args...)});
+         detail::make_args_checked<Args...>(format_str, args...));
 }
 FMT_END_NAMESPACE
 

include/fmt/posix.h

@@ -1,311 +1,2 @@
-// A C++ interface to POSIX functions.
-//
-// Copyright (c) 2012 - 2016, Victor Zverovich
-// All rights reserved.
-//
-// For the license information refer to format.h.
-
-#ifndef FMT_POSIX_H_
-#define FMT_POSIX_H_
-
-#if defined(__MINGW32__) || defined(__CYGWIN__)
-// Workaround MinGW bug https://sourceforge.net/p/mingw/bugs/2024/.
-#  undef __STRICT_ANSI__
-#endif
-
-#include <errno.h>
-#include <fcntl.h>   // for O_RDONLY
-#include <locale.h>  // for locale_t
-#include <stdio.h>
-#include <stdlib.h>  // for strtod_l
-
-#include <cstddef>
-
-#if defined __APPLE__ || defined(__FreeBSD__)
-#  include <xlocale.h>  // for LC_NUMERIC_MASK on OS X
-#endif
-
-#include "format.h"
-
-#ifndef FMT_POSIX
-#  if defined(_WIN32) && !defined(__MINGW32__)
-// Fix warnings about deprecated symbols.
-#    define FMT_POSIX(call) _##call
-#  else
-#    define FMT_POSIX(call) call
-#  endif
-#endif
-
-// Calls to system functions are wrapped in FMT_SYSTEM for testability.
-#ifdef FMT_SYSTEM
-#  define FMT_POSIX_CALL(call) FMT_SYSTEM(call)
-#else
-#  define FMT_SYSTEM(call) call
-#  ifdef _WIN32
-// Fix warnings about deprecated symbols.
-#    define FMT_POSIX_CALL(call) ::_##call
-#  else
-#    define FMT_POSIX_CALL(call) ::call
-#  endif
-#endif
-
-// Retries the expression while it evaluates to error_result and errno
-// equals to EINTR.
-#ifndef _WIN32
-#  define FMT_RETRY_VAL(result, expression, error_result) \
-    do {                                                  \
-      result = (expression);                              \
-    } while (result == error_result && errno == EINTR)
-#else
-#  define FMT_RETRY_VAL(result, expression, error_result) result = (expression)
-#endif
-
-#define FMT_RETRY(result, expression) FMT_RETRY_VAL(result, expression, -1)
-
-FMT_BEGIN_NAMESPACE
-
-/**
-  \rst
-  A reference to a null-terminated string. It can be constructed from a C
-  string or ``std::string``.
-
-  You can use one of the following type aliases for common character types:
-
-  +---------------+-----------------------------+
-  | Type          | Definition                  |
-  +===============+=============================+
-  | cstring_view  | basic_cstring_view<char>    |
-  +---------------+-----------------------------+
-  | wcstring_view | basic_cstring_view<wchar_t> |
-  +---------------+-----------------------------+
-
-  This class is most useful as a parameter type to allow passing
-  different types of strings to a function, for example::
-
-    template <typename... Args>
-    std::string format(cstring_view format_str, const Args & ... args);
-
-    format("{}", 42);
-    format(std::string("{}"), 42);
-  \endrst
- */
-template <typename Char> class basic_cstring_view {
- private:
-  const Char* data_;
-
- public:
-  /** Constructs a string reference object from a C string. */
-  basic_cstring_view(const Char* s) : data_(s) {}
-
-  /**
-    \rst
-    Constructs a string reference from an ``std::string`` object.
-    \endrst
-   */
-  basic_cstring_view(const std::basic_string<Char>& s) : data_(s.c_str()) {}
-
-  /** Returns the pointer to a C string. */
-  const Char* c_str() const { return data_; }
-};
-
-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_; }
-};
-
-// A buffered file.
-class buffered_file {
- private:
-  FILE* file_;
-
-  friend class file;
-
-  explicit buffered_file(FILE* f) : file_(f) {}
-
- public:
-  // Constructs a buffered_file object which doesn't represent any file.
-  buffered_file() FMT_NOEXCEPT : file_(nullptr) {}
-
-  // Destroys the object closing the file it represents if any.
-  FMT_API ~buffered_file() FMT_NOEXCEPT;
-
- private:
-  buffered_file(const buffered_file&) = delete;
-  void operator=(const buffered_file&) = delete;
-
- public:
-  buffered_file(buffered_file&& other) FMT_NOEXCEPT : file_(other.file_) {
-    other.file_ = nullptr;
-  }
-
-  buffered_file& operator=(buffered_file&& other) {
-    close();
-    file_ = other.file_;
-    other.file_ = nullptr;
-    return *this;
-  }
-
-  // Opens a file.
-  FMT_API buffered_file(cstring_view filename, cstring_view mode);
-
-  // Closes the file.
-  FMT_API void close();
-
-  // Returns the pointer to a FILE object representing this file.
-  FILE* get() const FMT_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;
-
-  void vprint(string_view format_str, format_args args) {
-    fmt::vprint(file_, format_str, args);
-  }
-
-  template <typename... Args>
-  inline void print(string_view format_str, const Args&... args) {
-    vprint(format_str, make_format_args(args...));
-  }
-};
-
-// A file. Closed file is represented by a file object with descriptor -1.
-// Methods that are not declared with FMT_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 {
- private:
-  int fd_;  // File descriptor.
-
-  // Constructs a file object with a given descriptor.
-  explicit file(int fd) : fd_(fd) {}
-
- public:
-  // Possible values for the oflag argument to the constructor.
-  enum {
-    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.
-  };
-
-  // Constructs a file object which doesn't represent any file.
-  file() FMT_NOEXCEPT : fd_(-1) {}
-
-  // Opens a file and constructs a file object representing this file.
-  FMT_API file(cstring_view path, int oflag);
-
- private:
-  file(const file&) = delete;
-  void operator=(const file&) = delete;
-
- public:
-  file(file&& other) FMT_NOEXCEPT : fd_(other.fd_) { other.fd_ = -1; }
-
-  file& operator=(file&& other) {
-    close();
-    fd_ = other.fd_;
-    other.fd_ = -1;
-    return *this;
-  }
-
-  // Destroys the object closing the file it represents if any.
-  FMT_API ~file() FMT_NOEXCEPT;
-
-  // Returns the file descriptor.
-  int descriptor() const FMT_NOEXCEPT { return fd_; }
-
-  // Closes the file.
-  FMT_API void close();
-
-  // Returns the file size. The size has signed type for consistency with
-  // stat::st_size.
-  FMT_API long long size() const;
-
-  // Attempts to read count bytes from the file into the specified buffer.
-  FMT_API std::size_t read(void* buffer, std::size_t count);
-
-  // Attempts to write count bytes from the specified buffer to the file.
-  FMT_API std::size_t write(const void* buffer, std::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);
-
-  // Makes fd be the copy of this file descriptor, closing fd first if
-  // necessary.
-  FMT_API 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;
-
-  // 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);
-
-  // 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);
-};
-
-// Returns the memory page size.
-long getpagesize();
-
-#ifdef FMT_LOCALE
-// A "C" numeric locale.
-class Locale {
- private:
-#  ifdef _WIN32
-  using locale_t = _locale_t;
-
-  enum { LC_NUMERIC_MASK = LC_NUMERIC };
-
-  static locale_t newlocale(int category_mask, const char* locale, locale_t) {
-    return _create_locale(category_mask, locale);
-  }
-
-  static void freelocale(locale_t locale) { _free_locale(locale); }
-
-  static double strtod_l(const char* nptr, char** endptr, _locale_t locale) {
-    return _strtod_l(nptr, endptr, locale);
-  }
-#  endif
-
-  locale_t locale_;
-
-  Locale(const Locale&) = delete;
-  void operator=(const Locale&) = delete;
-
- public:
-  using type = locale_t;
-
-  Locale() : locale_(newlocale(LC_NUMERIC_MASK, "C", nullptr)) {
-    if (!locale_) FMT_THROW(system_error(errno, "cannot create locale"));
-  }
-  ~Locale() { freelocale(locale_); }
-
-  type get() const { return locale_; }
-
-  // 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;
-  }
-};
-#endif  // FMT_LOCALE
-FMT_END_NAMESPACE
-
-#endif  // FMT_POSIX_H_
+#include "os.h"
+#warning "fmt/posix.h is deprecated; use fmt/os.h instead"

include/fmt/printf.h

@@ -1,4 +1,4 @@
-// Formatting library for C++
+// Formatting library for C++ - legacy printf implementation
 //
 // Copyright (c) 2012 - 2016, Victor Zverovich
 // All rights reserved.
@@ -8,17 +8,13 @@
 #ifndef FMT_PRINTF_H_
 #define FMT_PRINTF_H_
 
-#include <algorithm>  // std::fill_n
+#include <algorithm>  // std::max
 #include <limits>     // std::numeric_limits
 
 #include "ostream.h"
 
 FMT_BEGIN_NAMESPACE
-namespace internal {
-
-// A helper function to suppress bogus "conditional expression is constant"
-// warnings.
-template <typename T> inline T const_check(T value) { return value; }
+namespace detail {
 
 // Checks if a value fits in int - used to avoid warnings about comparing
 // signed and unsigned integers.
@@ -32,7 +28,7 @@ template <bool IsSigned> struct int_checker {
 
 template <> struct int_checker<true> {
   template <typename T> static bool fits_in_int(T value) {
-    return value >= std::numeric_limits<int>::min() &&
+    return value >= (std::numeric_limits<int>::min)() &&
            value <= max_value<int>();
   }
   static bool fits_in_int(int) { return true; }
@@ -94,11 +90,11 @@ 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_ = internal::make_arg<Context>(
+        arg_ = detail::make_arg<Context>(
             static_cast<int>(static_cast<target_type>(value)));
       } else {
         using unsigned_type = typename make_unsigned_or_bool<target_type>::type;
-        arg_ = internal::make_arg<Context>(
+        arg_ = detail::make_arg<Context>(
             static_cast<unsigned>(static_cast<unsigned_type>(value)));
       }
     } else {
@@ -106,9 +102,9 @@ template <typename T, typename Context> class arg_converter {
         // 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_ = internal::make_arg<Context>(static_cast<long long>(value));
+        arg_ = detail::make_arg<Context>(static_cast<long long>(value));
       } else {
-        arg_ = internal::make_arg<Context>(
+        arg_ = detail::make_arg<Context>(
             static_cast<typename make_unsigned_or_bool<U>::type>(value));
       }
     }
@@ -137,7 +133,7 @@ template <typename Context> class char_converter {
 
   template <typename T, FMT_ENABLE_IF(std::is_integral<T>::value)>
   void operator()(T value) {
-    arg_ = internal::make_arg<Context>(
+    arg_ = detail::make_arg<Context>(
         static_cast<typename Context::char_type>(value));
   }
 
@@ -145,6 +141,13 @@ template <typename Context> class char_converter {
   void operator()(T) {}  // No conversion needed for non-integral types.
 };
 
+// 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; }
+};
+
 // 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 {
@@ -159,7 +162,7 @@ template <typename Char> class printf_width_handler {
   template <typename T, FMT_ENABLE_IF(std::is_integral<T>::value)>
   unsigned operator()(T value) {
     auto width = static_cast<uint32_or_64_or_128_t<T>>(value);
-    if (internal::is_negative(value)) {
+    if (detail::is_negative(value)) {
       specs_.align = align::left;
       width = 0 - width;
     }
@@ -176,23 +179,25 @@ template <typename Char> class printf_width_handler {
 };
 
 template <typename Char, typename Context>
-void printf(buffer<Char>& buf, basic_string_view<Char> format,
-            basic_format_args<Context> args) {
+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
 
-template <typename OutputIt, typename Char, typename Context>
-internal::truncating_iterator<OutputIt> printf(
-    internal::truncating_iterator<OutputIt> it, basic_string_view<Char> format,
-    basic_format_args<Context> args) {
-  return Context(it, format, args).format();
+// 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);
 }
-}  // namespace internal
-
-using internal::printf;  // For printing into memory_buffer.
-
-template <typename Range> class printf_arg_formatter;
+using detail::vprintf;
 
+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;
 
 /**
@@ -200,15 +205,15 @@ template <typename OutputIt, typename Char> class basic_printf_context;
   The ``printf`` argument formatter.
   \endrst
  */
-template <typename Range>
-class printf_arg_formatter : public internal::arg_formatter_base<Range> {
+template <typename OutputIt, typename Char>
+class printf_arg_formatter : public detail::arg_formatter_base<OutputIt, Char> {
  public:
-  using iterator = typename Range::iterator;
+  using iterator = OutputIt;
 
  private:
-  using char_type = typename Range::value_type;
-  using base = internal::arg_formatter_base<Range>;
-  using context_type = basic_printf_context<iterator, char_type>;
+  using char_type = Char;
+  using base = detail::arg_formatter_base<OutputIt, Char>;
+  using context_type = basic_printf_context<OutputIt, Char>;
 
   context_type& context_;
 
@@ -233,9 +238,9 @@ class printf_arg_formatter : public internal::arg_formatter_base<Range> {
     \endrst
    */
   printf_arg_formatter(iterator iter, format_specs& specs, context_type& ctx)
-      : base(Range(iter), &specs, internal::locale_ref()), context_(ctx) {}
+      : base(iter, &specs, detail::locale_ref()), context_(ctx) {}
 
-  template <typename T, FMT_ENABLE_IF(std::is_integral<T>::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.
@@ -250,7 +255,11 @@ class printf_arg_formatter : public internal::arg_formatter_base<Range> {
         return (*this)(static_cast<int>(value));
       fmt_specs.sign = sign::none;
       fmt_specs.alt = false;
-      fmt_specs.align = align::right;
+      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);
@@ -307,6 +316,8 @@ class printf_arg_formatter : public internal::arg_formatter_base<Range> {
 };
 
 template <typename T> struct printf_formatter {
+  printf_formatter() = delete;
+
   template <typename ParseContext>
   auto parse(ParseContext& ctx) -> decltype(ctx.begin()) {
     return ctx.begin();
@@ -314,17 +325,21 @@ template <typename T> struct printf_formatter {
 
   template <typename FormatContext>
   auto format(const T& value, FormatContext& ctx) -> decltype(ctx.out()) {
-    internal::format_value(internal::get_container(ctx.out()), value);
+    detail::format_value(detail::get_container(ctx.out()), value);
     return ctx.out();
   }
 };
 
-/** This template formats data and writes the output to a writer. */
+/**
+ 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:
@@ -332,24 +347,23 @@ template <typename OutputIt, typename Char> class basic_printf_context {
 
   OutputIt out_;
   basic_format_args<basic_printf_context> args_;
-  basic_parse_context<Char> parse_ctx_;
+  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 equal
-  // to the maximum unsigned value, the next argument.
-  format_arg get_arg(unsigned arg_index = internal::max_value<unsigned>());
+  // 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.
-  unsigned parse_header(const Char*& it, const Char* end, format_specs& specs);
+  int parse_header(const Char*& it, const Char* end, format_specs& specs);
 
  public:
   /**
    \rst
-   Constructs a ``printf_context`` object. References to the arguments and
-   the writer are stored in the context object so make sure they have
-   appropriate lifetimes.
+   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,
@@ -359,16 +373,18 @@ template <typename OutputIt, typename Char> class basic_printf_context {
   OutputIt out() { return out_; }
   void advance_to(OutputIt it) { out_ = it; }
 
-  format_arg arg(unsigned id) const { return args_.get(id); }
+  detail::locale_ref locale() { return {}; }
 
-  basic_parse_context<Char>& parse_context() { return parse_ctx_; }
+  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<buffer_range<Char>>>
+  template <typename ArgFormatter = printf_arg_formatter<OutputIt, Char>>
   OutputIt format();
 };
 
@@ -388,7 +404,9 @@ void basic_printf_context<OutputIt, Char>::parse_flags(format_specs& specs,
       specs.fill[0] = '0';
       break;
     case ' ':
-      specs.sign = sign::space;
+      if (specs.sign != sign::plus) {
+        specs.sign = sign::space;
+      }
       break;
     case '#':
       specs.alt = true;
@@ -401,24 +419,25 @@ 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(unsigned arg_index) {
-  if (arg_index == internal::max_value<unsigned>())
+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 internal::get_arg(*this, arg_index);
+  return detail::get_arg(*this, arg_index);
 }
 
 template <typename OutputIt, typename Char>
-unsigned basic_printf_context<OutputIt, Char>::parse_header(
-    const Char*& it, const Char* end, format_specs& specs) {
-  unsigned arg_index = internal::max_value<unsigned>();
+int basic_printf_context<OutputIt, Char>::parse_header(const Char*& it,
+                                                       const Char* end,
+                                                       format_specs& specs) {
+  int arg_index = -1;
   char_type c = *it;
   if (c >= '0' && c <= '9') {
     // Parse an argument index (if followed by '$') or a width possibly
     // preceded with '0' flag(s).
-    internal::error_handler eh;
-    unsigned value = parse_nonnegative_int(it, end, eh);
+    detail::error_handler eh;
+    int value = parse_nonnegative_int(it, end, eh);
     if (it != end && *it == '$') {  // value is an argument index
       ++it;
       arg_index = value;
@@ -436,12 +455,12 @@ unsigned basic_printf_context<OutputIt, Char>::parse_header(
   // Parse width.
   if (it != end) {
     if (*it >= '0' && *it <= '9') {
-      internal::error_handler eh;
+      detail::error_handler eh;
       specs.width = parse_nonnegative_int(it, end, eh);
     } else if (*it == '*') {
       ++it;
-      specs.width = visit_format_arg(
-          internal::printf_width_handler<char_type>(specs), get_arg());
+      specs.width = static_cast<int>(visit_format_arg(
+          detail::printf_width_handler<char_type>(specs), get_arg()));
     }
   }
   return arg_index;
@@ -468,38 +487,53 @@ OutputIt basic_printf_context<OutputIt, Char>::format() {
     specs.align = align::right;
 
     // Parse argument index, flags and width.
-    unsigned arg_index = parse_header(it, end, specs);
+    int arg_index = parse_header(it, end, specs);
+    if (arg_index == 0) on_error("argument not found");
 
     // Parse precision.
     if (it != end && *it == '.') {
       ++it;
       c = it != end ? *it : 0;
       if ('0' <= c && c <= '9') {
-        internal::error_handler eh;
-        specs.precision = static_cast<int>(parse_nonnegative_int(it, end, eh));
+        detail::error_handler eh;
+        specs.precision = parse_nonnegative_int(it, end, eh);
       } else if (c == '*') {
         ++it;
-        specs.precision =
-            visit_format_arg(internal::printf_precision_handler(), get_arg());
+        specs.precision = static_cast<int>(
+            visit_format_arg(detail::printf_precision_handler(), get_arg()));
       } else {
         specs.precision = 0;
       }
     }
 
     format_arg arg = get_arg(arg_index);
-    if (specs.alt && visit_format_arg(internal::is_zero_int(), arg))
+    // 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);
+      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)));
+    }
+    if (specs.alt && visit_format_arg(detail::is_zero_int(), arg))
       specs.alt = false;
     if (specs.fill[0] == '0') {
-      if (arg.is_arithmetic())
+      if (arg.is_arithmetic() && specs.align != align::left)
         specs.align = align::numeric;
       else
-        specs.fill[0] = ' ';  // Ignore '0' flag for non-numeric types.
+        specs.fill[0] = ' ';  // Ignore '0' flag for non-numeric types or if '-'
+                              // flag is also present.
     }
 
     // Parse length and convert the argument to the required type.
     c = it != end ? *it++ : 0;
     char_type t = it != end ? *it : 0;
-    using internal::convert_arg;
+    using detail::convert_arg;
     switch (c) {
     case 'h':
       if (t == 'h') {
@@ -523,7 +557,7 @@ OutputIt basic_printf_context<OutputIt, Char>::format() {
       convert_arg<intmax_t>(arg, t);
       break;
     case 'z':
-      convert_arg<std::size_t>(arg, t);
+      convert_arg<size_t>(arg, t);
       break;
     case 't':
       convert_arg<std::ptrdiff_t>(arg, t);
@@ -548,7 +582,7 @@ OutputIt basic_printf_context<OutputIt, Char>::format() {
         specs.type = 'd';
         break;
       case 'c':
-        visit_format_arg(internal::char_converter<basic_printf_context>(arg),
+        visit_format_arg(detail::char_converter<basic_printf_context>(arg),
                          arg);
         break;
       }
@@ -557,15 +591,14 @@ OutputIt basic_printf_context<OutputIt, Char>::format() {
     start = it;
 
     // Format argument.
-    visit_format_arg(ArgFormatter(out, specs, *this), arg);
+    out = visit_format_arg(ArgFormatter(out, specs, *this), arg);
   }
   return std::copy(start, it, out);
 }
 
 template <typename Char>
 using basic_printf_context_t =
-    basic_printf_context<std::back_insert_iterator<internal::buffer<Char>>,
-                         Char>;
+    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>;
@@ -599,9 +632,10 @@ inline format_arg_store<wprintf_context, Args...> make_wprintf_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<Char>> args) {
+    const S& format,
+    basic_format_args<basic_printf_context_t<type_identity_t<Char>>> args) {
   basic_memory_buffer<Char> buffer;
-  printf(buffer, to_string_view(format), args);
+  vprintf(buffer, to_string_view(format), args);
   return to_string(buffer);
 }
 
@@ -615,18 +649,19 @@ inline std::basic_string<Char> vsprintf(
   \endrst
 */
 template <typename S, typename... Args,
-          typename Char = enable_if_t<internal::is_string<S>::value, char_t<S>>>
+          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...)});
+  return vsprintf(to_string_view(format), make_format_args<context>(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<Char>> args) {
+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;
-  printf(buffer, to_string_view(format), args);
-  std::size_t size = buffer.size();
+  vprintf(buffer, to_string_view(format), args);
+  size_t size = buffer.size();
   return std::fwrite(buffer.data(), sizeof(Char), size, f) < size
              ? -1
              : static_cast<int>(size);
@@ -642,16 +677,17 @@ inline int vfprintf(std::FILE* f, const S& format,
   \endrst
  */
 template <typename S, typename... Args,
-          typename Char = enable_if_t<internal::is_string<S>::value, char_t<S>>>
+          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...)});
+                  make_format_args<context>(args...));
 }
 
 template <typename S, typename Char = char_t<S>>
-inline int vprintf(const S& format,
-                   basic_format_args<basic_printf_context_t<Char>> args) {
+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);
 }
 
@@ -665,19 +701,20 @@ inline int vprintf(const S& format,
   \endrst
  */
 template <typename S, typename... Args,
-          FMT_ENABLE_IF(internal::is_string<S>::value)>
+          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...)});
+                 make_format_args<context>(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<Char>> args) {
+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;
-  printf(buffer, to_string_view(format), args);
-  internal::write(os, buffer);
+  vprintf(buffer, to_string_view(format), args);
+  detail::write_buffer(os, buffer);
   return static_cast<int>(buffer.size());
 }
 
@@ -685,9 +722,9 @@ inline int vfprintf(std::basic_ostream<Char>& os, const S& format,
 template <typename ArgFormatter, typename Char,
           typename Context =
               basic_printf_context<typename ArgFormatter::iterator, Char>>
-typename ArgFormatter::iterator vprintf(internal::buffer<Char>& out,
-                                        basic_string_view<Char> format_str,
-                                        basic_format_args<Context> args) {
+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;
@@ -707,7 +744,7 @@ 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...)});
+                  make_format_args<context>(args...));
 }
 FMT_END_NAMESPACE
 

include/fmt/ranges.h

@@ -12,7 +12,9 @@
 #ifndef FMT_RANGES_H_
 #define FMT_RANGES_H_
 
+#include <initializer_list>
 #include <type_traits>
+
 #include "format.h"
 
 // output only up to N items from the range.
@@ -31,7 +33,7 @@ template <typename Char> struct formatting_base {
 
 template <typename Char, typename Enable = void>
 struct formatting_range : formatting_base<Char> {
-  static FMT_CONSTEXPR_DECL const std::size_t range_length_limit =
+  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;
@@ -52,7 +54,7 @@ struct formatting_tuple : formatting_base<Char> {
   static FMT_CONSTEXPR_DECL const bool add_prepostfix_space = false;
 };
 
-namespace internal {
+namespace detail {
 
 template <typename RangeT, typename OutputIterator>
 OutputIterator copy(const RangeT& range, OutputIterator out) {
@@ -104,10 +106,7 @@ struct is_range_<
 /// 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,
-                  (void)std::declval<typename std::tuple_element<0, U>::type>(),
-                  int());
+  static auto check(U* p) -> decltype(std::tuple_size<U>::value, int());
   template <typename> static void check(...);
 
  public:
@@ -119,26 +118,24 @@ template <typename T> class is_tuple_like_ {
 #if defined(__cpp_lib_integer_sequence) || FMT_MSC_VER >= 1900
 template <typename T, T... N>
 using integer_sequence = std::integer_sequence<T, N...>;
-template <std::size_t... N> using index_sequence = std::index_sequence<N...>;
-template <std::size_t N>
-using make_index_sequence = std::make_index_sequence<N>;
+template <size_t... N> using index_sequence = std::index_sequence<N...>;
+template <size_t N> using make_index_sequence = std::make_index_sequence<N>;
 #else
 template <typename T, T... N> struct integer_sequence {
   using value_type = T;
 
-  static FMT_CONSTEXPR std::size_t size() { return sizeof...(N); }
+  static FMT_CONSTEXPR size_t size() { return sizeof...(N); }
 };
 
-template <std::size_t... N>
-using index_sequence = integer_sequence<std::size_t, N...>;
+template <size_t... N> using index_sequence = integer_sequence<size_t, N...>;
 
-template <typename T, std::size_t N, T... Ns>
+template <typename T, size_t N, T... Ns>
 struct make_integer_sequence : make_integer_sequence<T, N - 1, N - 1, Ns...> {};
 template <typename T, T... Ns>
 struct make_integer_sequence<T, 0, Ns...> : integer_sequence<T, Ns...> {};
 
-template <std::size_t N>
-using make_index_sequence = make_integer_sequence<std::size_t, N>;
+template <size_t N>
+using make_index_sequence = make_integer_sequence<size_t, N>;
 #endif
 
 template <class Tuple, class F, size_t... Is>
@@ -186,11 +183,11 @@ FMT_CONSTEXPR const wchar_t* format_str_quoted(bool add_space, const wchar_t) {
   return add_space ? L" '{}'" : L"'{}'";
 }
 
-}  // namespace internal
+}  // namespace detail
 
 template <typename T> struct is_tuple_like {
   static FMT_CONSTEXPR_DECL const bool value =
-      internal::is_tuple_like_<T>::value && !internal::is_range_<T>::value;
+      detail::is_tuple_like_<T>::value && !detail::is_range_<T>::value;
 };
 
 template <typename TupleT, typename Char>
@@ -203,17 +200,17 @@ struct formatter<TupleT, Char, enable_if_t<fmt::is_tuple_like<TupleT>::value>> {
         if (formatting.add_prepostfix_space) {
           *out++ = ' ';
         }
-        out = internal::copy(formatting.delimiter, out);
+        out = detail::copy(formatting.delimiter, out);
       }
       out = format_to(out,
-                      internal::format_str_quoted(
+                      detail::format_str_quoted(
                           (formatting.add_delimiter_spaces && i > 0), v),
                       v);
       ++i;
     }
 
     formatting_tuple<Char>& formatting;
-    std::size_t& i;
+    size_t& i;
     typename std::add_lvalue_reference<decltype(
         std::declval<FormatContext>().out())>::type out;
   };
@@ -229,14 +226,14 @@ struct formatter<TupleT, Char, enable_if_t<fmt::is_tuple_like<TupleT>::value>> {
   template <typename FormatContext = format_context>
   auto format(const TupleT& values, FormatContext& ctx) -> decltype(ctx.out()) {
     auto out = ctx.out();
-    std::size_t i = 0;
-    internal::copy(formatting.prefix, out);
+    size_t i = 0;
+    detail::copy(formatting.prefix, out);
 
-    internal::for_each(values, format_each<FormatContext>{formatting, i, out});
+    detail::for_each(values, format_each<FormatContext>{formatting, i, out});
     if (formatting.add_prepostfix_space) {
       *out++ = ' ';
     }
-    internal::copy(formatting.postfix, out);
+    detail::copy(formatting.postfix, out);
 
     return ctx.out();
   }
@@ -244,10 +241,9 @@ struct formatter<TupleT, Char, enable_if_t<fmt::is_tuple_like<TupleT>::value>> {
 
 template <typename T, typename Char> struct is_range {
   static FMT_CONSTEXPR_DECL const bool value =
-      internal::is_range_<T>::value &&
-      !internal::is_like_std_string<T>::value &&
+      detail::is_range_<T>::value && !detail::is_like_std_string<T>::value &&
       !std::is_convertible<T, std::basic_string<Char>>::value &&
-      !std::is_constructible<internal::std_string_view<Char>, T>::value;
+      !std::is_constructible<detail::std_string_view<Char>, T>::value;
 };
 
 template <typename RangeT, typename Char>
@@ -263,15 +259,17 @@ struct formatter<RangeT, Char,
   template <typename FormatContext>
   typename FormatContext::iterator format(const RangeT& values,
                                           FormatContext& ctx) {
-    auto out = internal::copy(formatting.prefix, ctx.out());
-    std::size_t i = 0;
-    for (auto it = values.begin(), end = values.end(); it != end; ++it) {
+    auto out = detail::copy(formatting.prefix, ctx.out());
+    size_t i = 0;
+    auto it = values.begin();
+    auto end = values.end();
+    for (; it != end; ++it) {
       if (i > 0) {
         if (formatting.add_prepostfix_space) *out++ = ' ';
-        out = internal::copy(formatting.delimiter, out);
+        out = detail::copy(formatting.delimiter, out);
       }
       out = format_to(out,
-                      internal::format_str_quoted(
+                      detail::format_str_quoted(
                           (formatting.add_delimiter_spaces && i > 0), *it),
                       *it);
       if (++i > formatting.range_length_limit) {
@@ -280,11 +278,11 @@ struct formatter<RangeT, Char,
       }
     }
     if (formatting.add_prepostfix_space) *out++ = ' ';
-    return internal::copy(formatting.postfix, out);
+    return detail::copy(formatting.postfix, out);
   }
 };
 
-template <typename Char, typename... T> struct tuple_arg_join : internal::view {
+template <typename Char, typename... T> struct tuple_arg_join : detail::view {
   const std::tuple<T...>& tuple;
   basic_string_view<Char> sep;
 
@@ -302,14 +300,14 @@ struct formatter<tuple_arg_join<Char, T...>, Char> {
   template <typename FormatContext>
   typename FormatContext::iterator format(
       const tuple_arg_join<Char, T...>& value, FormatContext& ctx) {
-    return format(value, ctx, internal::make_index_sequence<sizeof...(T)>{});
+    return format(value, ctx, detail::make_index_sequence<sizeof...(T)>{});
   }
 
  private:
   template <typename FormatContext, size_t... N>
   typename FormatContext::iterator format(
       const tuple_arg_join<Char, T...>& value, FormatContext& ctx,
-      internal::index_sequence<N...>) {
+      detail::index_sequence<N...>) {
     return format_args(value, ctx, std::get<N>(value.tuple)...);
   }
 
@@ -360,6 +358,29 @@ FMT_CONSTEXPR tuple_arg_join<wchar_t, T...> join(const std::tuple<T...>& tuple,
   return {tuple, sep};
 }
 
+/**
+  \rst
+  Returns an object that formats `initializer_list` with elements separated by
+  `sep`.
+
+  **Example**::
+
+    fmt::print("{}", fmt::join({1, 2, 3}, ", "));
+    // Output: "1, 2, 3"
+  \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) {
+  return join(std::begin(list), std::end(list), sep);
+}
+
 FMT_END_NAMESPACE
 
 #endif  // FMT_RANGES_H_

include/fmt/safe-duration-cast.h

@@ -1,293 +0,0 @@
-/*
- * For conversion between std::chrono::durations without undefined
- * behaviour or erroneous results.
- * This is a stripped down version of duration_cast, for inclusion in fmt.
- * See https://github.com/pauldreik/safe_duration_cast
- *
- * Copyright Paul Dreik 2019
- *
- * This file is licensed under the fmt license, see format.h
- */
-
-#include <chrono>
-#include <cmath>
-#include <limits>
-#include <type_traits>
-
-#include "format.h"
-
-FMT_BEGIN_NAMESPACE
-
-namespace safe_duration_cast {
-
-template <typename To, typename From,
-          FMT_ENABLE_IF(!std::is_same<From, To>::value &&
-                        std::numeric_limits<From>::is_signed ==
-                            std::numeric_limits<To>::is_signed)>
-FMT_CONSTEXPR To lossless_integral_conversion(const From from, int& ec) {
-  ec = 0;
-  using F = std::numeric_limits<From>;
-  using T = std::numeric_limits<To>;
-  static_assert(F::is_integer, "From must be integral");
-  static_assert(T::is_integer, "To must be integral");
-
-  // A and B are both signed, or both unsigned.
-  if (F::digits <= T::digits) {
-    // From fits in To without any problem.
-  } else {
-    // From does not always fit in To, resort to a dynamic check.
-    if (from < T::min() || from > T::max()) {
-      // outside range.
-      ec = 1;
-      return {};
-    }
-  }
-  return static_cast<To>(from);
-}
-
-/**
- * converts From to To, without loss. If the dynamic value of from
- * can't be converted to To without loss, ec is set.
- */
-template <typename To, typename From,
-          FMT_ENABLE_IF(!std::is_same<From, To>::value &&
-                        std::numeric_limits<From>::is_signed !=
-                            std::numeric_limits<To>::is_signed)>
-FMT_CONSTEXPR To lossless_integral_conversion(const From from, int& ec) {
-  ec = 0;
-  using F = std::numeric_limits<From>;
-  using T = std::numeric_limits<To>;
-  static_assert(F::is_integer, "From must be integral");
-  static_assert(T::is_integer, "To must be integral");
-
-  if (F::is_signed && !T::is_signed) {
-    // From may be negative, not allowed!
-    if (fmt::internal::is_negative(from)) {
-      ec = 1;
-      return {};
-    }
-
-    // From is positive. Can it always fit in To?
-    if (F::digits <= T::digits) {
-      // yes, From always fits in To.
-    } else {
-      // from may not fit in To, we have to do a dynamic check
-      if (from > static_cast<From>(T::max())) {
-        ec = 1;
-        return {};
-      }
-    }
-  }
-
-  if (!F::is_signed && T::is_signed) {
-    // can from be held in To?
-    if (F::digits < T::digits) {
-      // yes, From always fits in To.
-    } else {
-      // from may not fit in To, we have to do a dynamic check
-      if (from > static_cast<From>(T::max())) {
-        // outside range.
-        ec = 1;
-        return {};
-      }
-    }
-  }
-
-  // reaching here means all is ok for lossless conversion.
-  return static_cast<To>(from);
-
-}  // function
-
-template <typename To, typename From,
-          FMT_ENABLE_IF(std::is_same<From, To>::value)>
-FMT_CONSTEXPR To lossless_integral_conversion(const From from, int& ec) {
-  ec = 0;
-  return from;
-}  // function
-
-// clang-format off
-/**
- * converts From to To if possible, otherwise ec is set.
- *
- * input                            |    output
- * ---------------------------------|---------------
- * NaN                              | NaN
- * Inf                              | Inf
- * normal, fits in output           | converted (possibly lossy)
- * normal, does not fit in output   | ec is set
- * subnormal                        | best effort
- * -Inf                             | -Inf
- */
-// clang-format on
-template <typename To, typename From,
-          FMT_ENABLE_IF(!std::is_same<From, To>::value)>
-FMT_CONSTEXPR To safe_float_conversion(const From from, int& ec) {
-  ec = 0;
-  using T = std::numeric_limits<To>;
-  static_assert(std::is_floating_point<From>::value, "From must be floating");
-  static_assert(std::is_floating_point<To>::value, "To must be floating");
-
-  // catch the only happy case
-  if (std::isfinite(from)) {
-    if (from >= T::lowest() && from <= T::max()) {
-      return static_cast<To>(from);
-    }
-    // not within range.
-    ec = 1;
-    return {};
-  }
-
-  // nan and inf will be preserved
-  return static_cast<To>(from);
-}  // function
-
-template <typename To, typename From,
-          FMT_ENABLE_IF(std::is_same<From, To>::value)>
-FMT_CONSTEXPR To safe_float_conversion(const From from, int& ec) {
-  ec = 0;
-  static_assert(std::is_floating_point<From>::value, "From must be floating");
-  return from;
-}
-
-/**
- * safe duration cast between integral durations
- */
-template <typename To, typename FromRep, typename FromPeriod,
-          FMT_ENABLE_IF(std::is_integral<FromRep>::value),
-          FMT_ENABLE_IF(std::is_integral<typename To::rep>::value)>
-To safe_duration_cast(std::chrono::duration<FromRep, FromPeriod> from,
-                      int& ec) {
-  using From = std::chrono::duration<FromRep, FromPeriod>;
-  ec = 0;
-  // the basic idea is that we need to convert from count() in the from type
-  // to count() in the To type, by multiplying it with this:
-  struct Factor
-      : std::ratio_divide<typename From::period, typename To::period> {};
-
-  static_assert(Factor::num > 0, "num must be positive");
-  static_assert(Factor::den > 0, "den must be positive");
-
-  // the conversion is like this: multiply from.count() with Factor::num
-  // /Factor::den and convert it to To::rep, all this without
-  // overflow/underflow. let's start by finding a suitable type that can hold
-  // both To, From and Factor::num
-  using IntermediateRep =
-      typename std::common_type<typename From::rep, typename To::rep,
-                                decltype(Factor::num)>::type;
-
-  // safe conversion to IntermediateRep
-  IntermediateRep count =
-      lossless_integral_conversion<IntermediateRep>(from.count(), ec);
-  if (ec) {
-    return {};
-  }
-  // multiply with Factor::num without overflow or underflow
-  if (Factor::num != 1) {
-    const auto max1 = internal::max_value<IntermediateRep>() / Factor::num;
-    if (count > max1) {
-      ec = 1;
-      return {};
-    }
-    const auto min1 = std::numeric_limits<IntermediateRep>::min() / Factor::num;
-    if (count < min1) {
-      ec = 1;
-      return {};
-    }
-    count *= Factor::num;
-  }
-
-  // this can't go wrong, right? den>0 is checked earlier.
-  if (Factor::den != 1) {
-    count /= Factor::den;
-  }
-  // convert to the to type, safely
-  using ToRep = typename To::rep;
-  const ToRep tocount = lossless_integral_conversion<ToRep>(count, ec);
-  if (ec) {
-    return {};
-  }
-  return To{tocount};
-}
-
-/**
- * safe duration_cast between floating point durations
- */
-template <typename To, typename FromRep, typename FromPeriod,
-          FMT_ENABLE_IF(std::is_floating_point<FromRep>::value),
-          FMT_ENABLE_IF(std::is_floating_point<typename To::rep>::value)>
-To safe_duration_cast(std::chrono::duration<FromRep, FromPeriod> from,
-                      int& ec) {
-  using From = std::chrono::duration<FromRep, FromPeriod>;
-  ec = 0;
-  if (std::isnan(from.count())) {
-    // nan in, gives nan out. easy.
-    return To{std::numeric_limits<typename To::rep>::quiet_NaN()};
-  }
-  // maybe we should also check if from is denormal, and decide what to do about
-  // it.
-
-  // +-inf should be preserved.
-  if (std::isinf(from.count())) {
-    return To{from.count()};
-  }
-
-  // the basic idea is that we need to convert from count() in the from type
-  // to count() in the To type, by multiplying it with this:
-  struct Factor
-      : std::ratio_divide<typename From::period, typename To::period> {};
-
-  static_assert(Factor::num > 0, "num must be positive");
-  static_assert(Factor::den > 0, "den must be positive");
-
-  // the conversion is like this: multiply from.count() with Factor::num
-  // /Factor::den and convert it to To::rep, all this without
-  // overflow/underflow. let's start by finding a suitable type that can hold
-  // both To, From and Factor::num
-  using IntermediateRep =
-      typename std::common_type<typename From::rep, typename To::rep,
-                                decltype(Factor::num)>::type;
-
-  // force conversion of From::rep -> IntermediateRep to be safe,
-  // even if it will never happen be narrowing in this context.
-  IntermediateRep count =
-      safe_float_conversion<IntermediateRep>(from.count(), ec);
-  if (ec) {
-    return {};
-  }
-
-  // multiply with Factor::num without overflow or underflow
-  if (Factor::num != 1) {
-    constexpr auto max1 = internal::max_value<IntermediateRep>() /
-                          static_cast<IntermediateRep>(Factor::num);
-    if (count > max1) {
-      ec = 1;
-      return {};
-    }
-    constexpr auto min1 = std::numeric_limits<IntermediateRep>::lowest() /
-                          static_cast<IntermediateRep>(Factor::num);
-    if (count < min1) {
-      ec = 1;
-      return {};
-    }
-    count *= static_cast<IntermediateRep>(Factor::num);
-  }
-
-  // this can't go wrong, right? den>0 is checked earlier.
-  if (Factor::den != 1) {
-    using common_t = typename std::common_type<IntermediateRep, intmax_t>::type;
-    count /= static_cast<common_t>(Factor::den);
-  }
-
-  // convert to the to type, safely
-  using ToRep = typename To::rep;
-
-  const ToRep tocount = safe_float_conversion<ToRep>(count, ec);
-  if (ec) {
-    return {};
-  }
-  return To{tocount};
-}
-
-}  // namespace safe_duration_cast
-
-FMT_END_NAMESPACE

src/format.cc

@@ -8,50 +8,61 @@
 #include "fmt/format-inl.h"
 
 FMT_BEGIN_NAMESPACE
-template struct FMT_API internal::basic_data<void>;
+namespace detail {
 
-// Workaround a bug in MSVC2013 that prevents instantiation of grisu_format.
-bool (*instantiate_grisu_format)(double, internal::buffer<char>&, int, unsigned,
-                                 int&) = internal::grisu_format;
+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;
 
 #ifndef FMT_STATIC_THOUSANDS_SEPARATOR
-template FMT_API internal::locale_ref::locale_ref(const std::locale& loc);
-template FMT_API std::locale internal::locale_ref::get<std::locale>() const;
+template FMT_API detail::locale_ref::locale_ref(const std::locale& loc);
+template FMT_API std::locale detail::locale_ref::get<std::locale>() const;
 #endif
 
 // Explicit instantiations for char.
 
-template FMT_API char internal::thousands_sep_impl(locale_ref);
-template FMT_API char internal::decimal_point_impl(locale_ref);
+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 void internal::buffer<char>::append(const char*, const char*);
+template FMT_API void detail::buffer<char>::append(const char*, const char*);
 
-template FMT_API void internal::arg_map<format_context>::init(
-    const basic_format_args<format_context>& args);
+template FMT_API format_context::iterator detail::vformat_to(
+    detail::buffer<char>&, string_view, basic_format_args<format_context>);
 
-template FMT_API std::string internal::vformat<char>(
-    string_view, basic_format_args<format_context>);
-
-template FMT_API format_context::iterator internal::vformat_to(
-    internal::buffer<char>&, string_view, basic_format_args<format_context>);
-
-template FMT_API char* internal::sprintf_format(double, internal::buffer<char>&,
-                                                sprintf_specs);
-template FMT_API char* internal::sprintf_format(long double,
-                                                internal::buffer<char>&,
-                                                sprintf_specs);
+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>&);
 
 // Explicit instantiations for wchar_t.
 
-template FMT_API wchar_t internal::thousands_sep_impl(locale_ref);
-template FMT_API wchar_t internal::decimal_point_impl(locale_ref);
+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 void internal::buffer<wchar_t>::append(const wchar_t*,
-                                                        const wchar_t*);
-
-template FMT_API void internal::arg_map<wformat_context>::init(
-    const basic_format_args<wformat_context>&);
-
-template FMT_API std::wstring internal::vformat<wchar_t>(
-    wstring_view, basic_format_args<wformat_context>);
+template FMT_API void detail::buffer<wchar_t>::append(const wchar_t*,
+                                                      const wchar_t*);
 FMT_END_NAMESPACE

src/os.cc

@@ -1,4 +1,4 @@
-// A C++ interface to POSIX functions.
+// Formatting library for C++ - optional OS-specific functionality
 //
 // Copyright (c) 2012 - 2016, Victor Zverovich
 // All rights reserved.
@@ -10,37 +10,43 @@
 #  define _CRT_SECURE_NO_WARNINGS
 #endif
 
-#include "fmt/posix.h"
+#include "fmt/os.h"
 
 #include <climits>
-#include <sys/stat.h>
-#include <sys/types.h>
 
-#ifndef _WIN32
-#  include <unistd.h>
-#else
-#  ifndef WIN32_LEAN_AND_MEAN
-#    define WIN32_LEAN_AND_MEAN
-#  endif
-#  include <io.h>
+#if FMT_USE_FCNTL
+#  include <sys/stat.h>
+#  include <sys/types.h>
+
+#  ifndef _WIN32
+#    include <unistd.h>
+#  else
+#    ifndef WIN32_LEAN_AND_MEAN
+#      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
+#    endif
+#  endif  // _WIN32
+#endif    // FMT_USE_FCNTL
+
+#ifdef _WIN32
 #  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
-#  endif
-
-#endif  // _WIN32
+#endif
 
 #ifdef fileno
 #  undef fileno
@@ -66,6 +72,78 @@ 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"));
+  }
+}
+
+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;
+  }
+
+  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;
+}
+
+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));
+}
+
+void detail::format_windows_error(detail::buffer<char>& out, int error_code,
+                                  string_view message) FMT_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;
+      }
+      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 {
+  report_error(detail::format_windows_error, error_code, message);
+}
+#endif  // _WIN32
+
 buffered_file::~buffered_file() FMT_NOEXCEPT {
   if (file_ && FMT_SYSTEM(fclose(file_)) != 0)
     report_system_error(errno, "cannot close file");
@@ -94,14 +172,15 @@ int buffered_file::fileno() const {
   return fd;
 }
 
+#if FMT_USE_FCNTL
 file::file(cstring_view path, int oflag) {
   int mode = S_IRUSR | S_IWUSR;
-#if defined(_WIN32) && !defined(__MINGW32__)
+#  if defined(_WIN32) && !defined(__MINGW32__)
   fd_ = -1;
   FMT_POSIX_CALL(sopen_s(&fd_, path.c_str(), oflag, _SH_DENYNO, mode));
-#else
+#  else
   FMT_RETRY(fd_, FMT_POSIX_CALL(open(path.c_str(), oflag, mode)));
-#endif
+#  endif
   if (fd_ == -1)
     FMT_THROW(system_error(errno, "cannot open file {}", path.c_str()));
 }
@@ -123,7 +202,7 @@ void file::close() {
 }
 
 long long file::size() const {
-#ifdef _WIN32
+#  ifdef _WIN32
   // Use GetFileSize instead of GetFileSizeEx for the case when _WIN32_WINNT
   // is less than 0x0500 as is the case with some default MinGW builds.
   // Both functions support large file sizes.
@@ -137,7 +216,7 @@ long long file::size() const {
   }
   unsigned long long long_size = size_upper;
   return (long_size << sizeof(DWORD) * CHAR_BIT) | size_lower;
-#else
+#  else
   using Stat = struct stat;
   Stat file_stat = Stat();
   if (FMT_POSIX_CALL(fstat(fd_, &file_stat)) == -1)
@@ -145,21 +224,21 @@ long long file::size() const {
   static_assert(sizeof(long long) >= sizeof(file_stat.st_size),
                 "return type of file::size is not large enough");
   return file_stat.st_size;
-#endif
+#  endif
 }
 
 std::size_t file::read(void* buffer, std::size_t count) {
   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"));
-  return internal::to_unsigned(result);
+  return detail::to_unsigned(result);
 }
 
 std::size_t file::write(const void* buffer, std::size_t count) {
   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"));
-  return internal::to_unsigned(result);
+  return detail::to_unsigned(result);
 }
 
 file file::dup(int fd) {
@@ -192,15 +271,15 @@ void file::pipe(file& read_end, file& write_end) {
   read_end.close();
   write_end.close();
   int fds[2] = {};
-#ifdef _WIN32
+#  ifdef _WIN32
   // Make the default pipe capacity same as on Linux 2.6.11+.
   enum { DEFAULT_CAPACITY = 65536 };
   int result = FMT_POSIX_CALL(pipe(fds, DEFAULT_CAPACITY, _O_BINARY));
-#else
+#  else
   // Don't retry as the pipe function doesn't return EINTR.
   // http://pubs.opengroup.org/onlinepubs/009696799/functions/pipe.html
   int result = FMT_POSIX_CALL(pipe(fds));
-#endif
+#  endif
   if (result != 0) FMT_THROW(system_error(errno, "cannot create pipe"));
   // The following assignments don't throw because read_fd and write_fd
   // are closed.
@@ -210,7 +289,11 @@ 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_)
+  FILE* f = ::fdopen(fd_, mode);
+  #else
   FILE* f = FMT_POSIX_CALL(fdopen(fd_, mode));
+  #endif
   if (!f)
     FMT_THROW(
         system_error(errno, "cannot associate stream with file descriptor"));
@@ -220,14 +303,15 @@ buffered_file file::fdopen(const char* mode) {
 }
 
 long getpagesize() {
-#ifdef _WIN32
+#  ifdef _WIN32
   SYSTEM_INFO si;
   GetSystemInfo(&si);
   return si.dwPageSize;
-#else
+#  else
   long size = FMT_POSIX_CALL(sysconf(_SC_PAGESIZE));
   if (size < 0) FMT_THROW(system_error(errno, "cannot get memory page size"));
   return size;
-#endif
+#  endif
 }
+#endif  // FMT_USE_FCNTL
 FMT_END_NAMESPACE

support/Vagrantfile

@@ -3,7 +3,8 @@
 
 # A vagrant config for testing against gcc-4.8.
 Vagrant.configure("2") do |config|
-  config.vm.box = "ubuntu/trusty64"
+  config.vm.box = "ubuntu/xenial64"
+  config.disksize.size = '15GB'
 
   config.vm.provider "virtualbox" do |vb|
     vb.memory = "4096"

support/cmake/JoinPaths.cmake

@@ -0,0 +1,26 @@
+# This module provides function for joining paths
+# known from from most languages
+#
+# Original license:
+# SPDX-License-Identifier: (MIT OR CC0-1.0)
+# Explicit permission given to distribute this module under
+# the terms of the project as described in /LICENSE.rst.
+# Copyright 2020 Jan Tojnar
+# https://github.com/jtojnar/cmake-snips
+#
+# Modelled after Python’s os.path.join
+# https://docs.python.org/3.7/library/os.path.html#os.path.join
+# Windows not supported
+function(join_paths joined_path first_path_segment)
+    set(temp_path "${first_path_segment}")
+    foreach(current_segment IN LISTS ARGN)
+        if(NOT ("${current_segment}" STREQUAL ""))
+            if(IS_ABSOLUTE "${current_segment}")
+                set(temp_path "${current_segment}")
+            else()
+                set(temp_path "${temp_path}/${current_segment}")
+            endif()
+        endif()
+    endforeach()
+    set(${joined_path} "${temp_path}" PARENT_SCOPE)
+endfunction()

support/cmake/cxx14.cmake

@@ -48,17 +48,6 @@ endif ()
 
 set(CMAKE_REQUIRED_FLAGS ${CXX_STANDARD_FLAG})
 
-# Check if variadic templates are working and not affected by GCC bug 39653:
-# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=39653
-# Can be removed once gcc 4.4 support is dropped.
-check_cxx_source_compiles("
-  template <class T, class ...Types>
-  struct S { typedef typename S<Types...>::type type; };
-  int main() {}" SUPPORTS_VARIADIC_TEMPLATES)
-if (NOT SUPPORTS_VARIADIC_TEMPLATES)
-  set (SUPPORTS_VARIADIC_TEMPLATES OFF)
-endif ()
-
 # Check if user-defined literals are available
 check_cxx_source_compiles("
   void operator\"\" _udl(long double);

support/cmake/fmt.pc.in

@@ -1,11 +1,11 @@
 prefix=@CMAKE_INSTALL_PREFIX@
 exec_prefix=@CMAKE_INSTALL_PREFIX@
-libdir=${exec_prefix}/@CMAKE_INSTALL_LIBDIR@
-includedir=${prefix}/@CMAKE_INSTALL_INCLUDEDIR@
+libdir=@libdir_for_pc_file@
+includedir=@includedir_for_pc_file@
 
 Name: fmt
 Description: A modern formatting library
 Version: @FMT_VERSION@
-Libs: -L${libdir} -lfmt
+Libs: -L${libdir} -l@FMT_LIB_NAME@
 Cflags: -I${includedir}
 

support/manage.py

@@ -137,15 +137,23 @@ def update_site(env):
         if not os.path.exists(contents):
             os.rename(os.path.join(target_doc_dir, 'index.rst'), contents)
         # Fix issues in reference.rst/api.rst.
-        for filename in ['reference.rst', 'api.rst']:
+        for filename in ['reference.rst', 'api.rst', 'index.rst']:
             pattern = re.compile('doxygenfunction.. (bin|oct|hexu|hex)$', re.M)
             with rewrite(os.path.join(target_doc_dir, filename)) as b:
                 b.data = b.data.replace('std::ostream &', 'std::ostream&')
                 b.data = re.sub(pattern, r'doxygenfunction:: \1(int)', b.data)
                 b.data = b.data.replace('std::FILE*', 'std::FILE *')
                 b.data = b.data.replace('unsigned int', 'unsigned')
-                b.data = b.data.replace('operator""_', 'operator"" _')
+                #b.data = b.data.replace('operator""_', 'operator"" _')
                 b.data = b.data.replace(', size_t', ', std::size_t')
+                b.data = b.data.replace('aa long', 'a long')
+                b.data = b.data.replace('serveral', 'several')
+                if version.startswith('6.2.'):
+                    b.data = b.data.replace(
+                        'vformat(const S&, basic_format_args<' +
+                        'buffer_context<Char>>)',
+                        'vformat(const S&, basic_format_args<' +
+                        'buffer_context<type_identity_t<Char>>>)')
         # Fix a broken link in index.rst.
         index = os.path.join(target_doc_dir, 'index.rst')
         with rewrite(index) as b:

test/CMakeLists.txt

@@ -17,9 +17,7 @@ else ()
   target_compile_definitions(gmock PUBLIC GTEST_HAS_PTHREAD=0)
 endif ()
 
-if (NOT SUPPORTS_VARIADIC_TEMPLATES)
-  target_compile_definitions(gmock PUBLIC GTEST_LANG_CXX11=0)
-endif ()
+target_compile_definitions(gmock PUBLIC GTEST_LANG_CXX11=0)
 
 if (MSVC)
   # Workaround a bug in implementation of variadic templates in MSVC11.
@@ -47,8 +45,6 @@ target_compile_definitions(gmock
 
 set(TEST_MAIN_SRC test-main.cc gtest-extra.cc gtest-extra.h util.cc)
 add_library(test-main STATIC ${TEST_MAIN_SRC})
-target_compile_definitions(test-main PUBLIC
-  FMT_USE_FILE_DESCRIPTORS=$<BOOL:${HAVE_OPEN}>)
 target_include_directories(test-main SYSTEM PUBLIC gtest gmock)
 target_link_libraries(test-main gmock fmt)
 
@@ -113,12 +109,11 @@ add_fmt_test(custom-formatter-test)
 add_fmt_test(ranges-test)
 add_fmt_test(scan-test)
 
-if (HAVE_OPEN AND NOT MSVC_BUILD_STATIC)
+if (NOT MSVC_BUILD_STATIC)
   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_compile_definitions(posix-mock-test PRIVATE FMT_USE_FILE_DESCRIPTORS=1)
   target_link_libraries(posix-mock-test gmock)
   target_include_directories(posix-mock-test SYSTEM PUBLIC gtest gmock)
   if (FMT_PEDANTIC)
@@ -128,7 +123,7 @@ if (HAVE_OPEN AND NOT MSVC_BUILD_STATIC)
     target_compile_definitions(posix-mock-test PRIVATE FMT_LOCALE)
   endif ()
   add_test(NAME posix-mock-test COMMAND posix-mock-test)
-  add_fmt_test(posix-test)
+  add_fmt_test(os-test)
 endif ()
 
 add_fmt_executable(header-only-test
@@ -174,18 +169,6 @@ if (FMT_PEDANTIC)
   target_compile_definitions(
     nolocale-test PRIVATE FMT_STATIC_THOUSANDS_SEPARATOR=1)
 
-  # Test that the library compiles without windows.h.
-  if (CMAKE_SYSTEM_NAME STREQUAL "Windows")
-    add_library(no-windows-h-test ../src/format.cc)
-    target_include_directories(
-      no-windows-h-test PRIVATE ${PROJECT_SOURCE_DIR}/include)
-    target_compile_definitions(no-windows-h-test PRIVATE FMT_USE_WINDOWS_H=0)
-    if (FMT_PEDANTIC)
-      target_compile_options(no-windows-h-test PRIVATE ${PEDANTIC_COMPILE_FLAGS})
-    endif ()
-    target_include_directories(no-windows-h-test SYSTEM PUBLIC gtest gmock)
-  endif ()
-
   add_test(compile-error-test ${CMAKE_CTEST_COMMAND}
     --build-and-test
     "${CMAKE_CURRENT_SOURCE_DIR}/compile-error-test"
@@ -232,20 +215,22 @@ if (FMT_PEDANTIC AND NOT WIN32)
     "-DCMAKE_BUILD_TYPE=${CMAKE_BUILD_TYPE}")
 endif ()
 
-# Activate optional CUDA tests if CUDA is found. For version selection, see
+# 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 (${CMAKE_VERSION} VERSION_LESS 3.15)
-  find_package(CUDA 9.0)
-else ()
-  include(CheckLanguage)
-  check_language(CUDA)
-  if (CMAKE_CUDA_COMPILER)
-    enable_language(CUDA OPTIONAL)
-    set(CUDA_FOUND TRUE)
+if (FMT_CUDA_TEST)
+  if (${CMAKE_VERSION} VERSION_LESS 3.15)
+    find_package(CUDA 9.0)
+  else ()
+    include(CheckLanguage)
+    check_language(CUDA)
+    if (CMAKE_CUDA_COMPILER)
+      enable_language(CUDA OPTIONAL)
+      set(CUDA_FOUND TRUE)
+    endif ()
+  endif ()
+
+  if (CUDA_FOUND)
+    add_subdirectory(cuda-test)
+    add_test(NAME cuda-test COMMAND fmt-in-cuda-test)
   endif ()
 endif ()
-
-if (CUDA_FOUND)
-  add_subdirectory(cuda-test)
-  add_test(NAME cuda-test COMMAND fmt-in-cuda-test)
-endif ()

test/assert-test.cc

@@ -8,15 +8,21 @@
 #include "fmt/core.h"
 #include "gtest.h"
 
-#if GTEST_HAS_DEATH_TEST
-#  define EXPECT_DEBUG_DEATH_IF_SUPPORTED(statement, regex) \
-    EXPECT_DEBUG_DEATH(statement, regex)
-#else
-#  define EXPECT_DEBUG_DEATH_IF_SUPPORTED(statement, regex) \
-    GTEST_UNSUPPORTED_DEATH_TEST_(statement, regex, )
-#endif
-
 TEST(AssertTest, Fail) {
-  EXPECT_DEBUG_DEATH_IF_SUPPORTED(FMT_ASSERT(false, "don't panic!"),
-                                  "don't panic!");
+#if GTEST_HAS_DEATH_TEST
+  EXPECT_DEBUG_DEATH(FMT_ASSERT(false, "don't panic!"), "don't panic!");
+#else
+  fmt::print("warning: death tests are not supported\n");
+#endif
+}
+
+bool test_condition = false;
+
+TEST(AssertTest, DanglingElse) {
+  bool executed_else = false;
+  if (test_condition)
+    FMT_ASSERT(true, "");
+  else
+    executed_else = true;
+  EXPECT_TRUE(executed_else);
 }

test/chrono-test.cc

@@ -10,10 +10,11 @@
 #endif
 
 #include "fmt/chrono.h"
-#include "gtest-extra.h"
 
 #include <iomanip>
 
+#include "gtest-extra.h"
+
 std::tm make_tm() {
   auto time = std::tm();
   time.tm_mday = 1;
@@ -145,6 +146,48 @@ TEST(ChronoTest, FormatDefault) {
       fmt::format("{}", std::chrono::duration<int, std::ratio<15, 4>>(42)));
 }
 
+TEST(ChronoTest, FormatWide) {
+  EXPECT_EQ(L"42s", fmt::format(L"{}", std::chrono::seconds(42)));
+  EXPECT_EQ(L"42as",
+            fmt::format(L"{}", std::chrono::duration<int, std::atto>(42)));
+  EXPECT_EQ(L"42fs",
+            fmt::format(L"{}", std::chrono::duration<int, std::femto>(42)));
+  EXPECT_EQ(L"42ps",
+            fmt::format(L"{}", std::chrono::duration<int, std::pico>(42)));
+  EXPECT_EQ(L"42ns", fmt::format(L"{}", std::chrono::nanoseconds(42)));
+  EXPECT_EQ(L"42\u00B5s", fmt::format(L"{}", std::chrono::microseconds(42)));
+  EXPECT_EQ(L"42ms", fmt::format(L"{}", std::chrono::milliseconds(42)));
+  EXPECT_EQ(L"42cs",
+            fmt::format(L"{}", std::chrono::duration<int, std::centi>(42)));
+  EXPECT_EQ(L"42ds",
+            fmt::format(L"{}", std::chrono::duration<int, std::deci>(42)));
+  EXPECT_EQ(L"42s", fmt::format(L"{}", std::chrono::seconds(42)));
+  EXPECT_EQ(L"42das",
+            fmt::format(L"{}", std::chrono::duration<int, std::deca>(42)));
+  EXPECT_EQ(L"42hs",
+            fmt::format(L"{}", std::chrono::duration<int, std::hecto>(42)));
+  EXPECT_EQ(L"42ks",
+            fmt::format(L"{}", std::chrono::duration<int, std::kilo>(42)));
+  EXPECT_EQ(L"42Ms",
+            fmt::format(L"{}", std::chrono::duration<int, std::mega>(42)));
+  EXPECT_EQ(L"42Gs",
+            fmt::format(L"{}", std::chrono::duration<int, std::giga>(42)));
+  EXPECT_EQ(L"42Ts",
+            fmt::format(L"{}", std::chrono::duration<int, std::tera>(42)));
+  EXPECT_EQ(L"42Ps",
+            fmt::format(L"{}", std::chrono::duration<int, std::peta>(42)));
+  EXPECT_EQ(L"42Es",
+            fmt::format(L"{}", std::chrono::duration<int, std::exa>(42)));
+  EXPECT_EQ(L"42m", fmt::format(L"{}", std::chrono::minutes(42)));
+  EXPECT_EQ(L"42h", fmt::format(L"{}", std::chrono::hours(42)));
+  EXPECT_EQ(
+      L"42[15]s",
+      fmt::format(L"{}", std::chrono::duration<int, std::ratio<15, 1>>(42)));
+  EXPECT_EQ(
+      L"42[15/4]s",
+      fmt::format(L"{}", std::chrono::duration<int, std::ratio<15, 4>>(42)));
+}
+
 TEST(ChronoTest, Align) {
   auto s = std::chrono::seconds(42);
   EXPECT_EQ("42s  ", fmt::format("{:5}", s));

test/color-test.cc

@@ -6,6 +6,7 @@
 // For the license information refer to format.h.
 
 #include "fmt/color.h"
+
 #include "gtest-extra.h"
 
 TEST(ColorsTest, ColorsPrint) {
@@ -50,6 +51,8 @@ TEST(ColorsTest, ColorsPrint) {
 TEST(ColorsTest, 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(

test/compile-test.cc

@@ -6,6 +6,7 @@
 // For the license information refer to format.h.
 
 #include <stdint.h>
+
 #include <cctype>
 #include <cfloat>
 #include <climits>
@@ -39,8 +40,8 @@ using testing::StrictMock;
 #if FMT_USE_CONSTEXPR
 template <unsigned EXPECTED_PARTS_COUNT, typename Format>
 void check_prepared_parts_type(Format format) {
-  typedef fmt::internal::compiled_format_base<decltype(format)> provider;
-  typedef fmt::internal::format_part<char>
+  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,
@@ -66,46 +67,37 @@ TEST(CompileTest, CompileTimePreparedPartsTypeProvider) {
 #endif
 
 TEST(CompileTest, PassStringLiteralFormat) {
-  const auto prepared = fmt::compile<int>("test {}");
+  const auto prepared = fmt::detail::compile<int>("test {}");
   EXPECT_EQ("test 42", fmt::format(prepared, 42));
-  const auto wprepared = fmt::compile<int>(L"test {}");
+  const auto wprepared = fmt::detail::compile<int>(L"test {}");
   EXPECT_EQ(L"test 42", fmt::format(wprepared, 42));
 }
 
-#if FMT_USE_CONSTEXPR
-TEST(CompileTest, PassCompileString) {
-  const auto prepared = fmt::compile<int>(FMT_STRING("test {}"));
-  EXPECT_EQ("test 42", fmt::format(prepared, 42));
-  const auto wprepared = fmt::compile<int>(FMT_STRING(L"test {}"));
-  EXPECT_EQ(L"test 42", fmt::format(wprepared, 42));
-}
-#endif
-
 TEST(CompileTest, FormatToArrayOfChars) {
   char buffer[32] = {0};
-  const auto prepared = fmt::compile<int>("4{}");
-  fmt::format_to(fmt::internal::make_checked(buffer, 32), prepared, 2);
+  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::compile<int>(L"4{}");
-  fmt::format_to(fmt::internal::make_checked(wbuffer, 32), wprepared, 2);
+  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::compile<int>("4{}");
+  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::compile<int>(L"4{}");
+  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::compile<int>("{:10}");
+  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);
@@ -113,12 +105,12 @@ TEST(CompileTest, FormatToN) {
 }
 
 TEST(CompileTest, FormattedSize) {
-  auto f = fmt::compile<int>("{:10}");
+  auto f = fmt::detail::compile<int>("{:10}");
   EXPECT_EQ(fmt::formatted_size(f, 42), 10);
 }
 
 TEST(CompileTest, MultipleTypes) {
-  auto f = fmt::compile<int, int>("{} {}");
+  auto f = fmt::detail::compile<int, int>("{} {}");
   EXPECT_EQ(fmt::format(f, 42, 42), "42 42");
 }
 
@@ -126,18 +118,49 @@ struct formattable {};
 
 FMT_BEGIN_NAMESPACE
 template <> struct formatter<formattable> : formatter<const char*> {
-  auto format(formattable, format_context& ctx) -> decltype(ctx.out()) {
+  template <typename FormatContext>
+  auto format(formattable, FormatContext& ctx) -> decltype(ctx.out()) {
     return formatter<const char*>::format("foo", ctx);
   }
 };
 FMT_END_NAMESPACE
 
 TEST(CompileTest, FormatUserDefinedType) {
-  auto f = fmt::compile<formattable>("{}");
+  auto f = fmt::detail::compile<formattable>("{}");
   EXPECT_EQ(fmt::format(f, formattable()), "foo");
 }
 
 TEST(CompileTest, EmptyFormatString) {
-  auto f = fmt::compile<>("");
+  auto f = fmt::detail::compile<>("");
   EXPECT_EQ(fmt::format(f), "");
 }
+
+#ifdef __cpp_if_constexpr
+TEST(CompileTest, FormatDefault) {
+  EXPECT_EQ("42", fmt::format(FMT_COMPILE("{}"), 42));
+  EXPECT_EQ("42", fmt::format(FMT_COMPILE("{}"), 42u));
+  EXPECT_EQ("42", fmt::format(FMT_COMPILE("{}"), 42ll));
+  EXPECT_EQ("42", fmt::format(FMT_COMPILE("{}"), 42ull));
+  EXPECT_EQ("true", fmt::format(FMT_COMPILE("{}"), true));
+  EXPECT_EQ("x", fmt::format(FMT_COMPILE("{}"), 'x'));
+  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()));
+}
+
+TEST(CompileTest, FormatSpecs) {
+  EXPECT_EQ("42", fmt::format(FMT_COMPILE("{:x}"), 0x42));
+}
+
+TEST(CompileTest, FormatTo) {
+  char buf[8];
+  auto end = fmt::format_to(buf, FMT_COMPILE("{}"), 42);
+  *end = '\0';
+  EXPECT_STREQ("42", buf);
+}
+
+TEST(CompileTest, TextAndArg) {
+  EXPECT_EQ(">>>42<<<", fmt::format(FMT_COMPILE(">>>{}<<<"), 42));
+}
+#endif

test/core-test.cc

@@ -15,9 +15,8 @@
 #include <string>
 #include <type_traits>
 
-#include "test-assert.h"
-
 #include "gmock.h"
+#include "test-assert.h"
 
 // Check if fmt/core.h compiles with windows.h included before it.
 #ifdef _WIN32
@@ -31,8 +30,8 @@
 
 using fmt::basic_format_arg;
 using fmt::string_view;
-using fmt::internal::buffer;
-using fmt::internal::value;
+using fmt::detail::buffer;
+using fmt::detail::value;
 
 using testing::_;
 using testing::StrictMock;
@@ -43,7 +42,7 @@ struct test_struct {};
 
 template <typename Context, typename T>
 basic_format_arg<Context> make_arg(const T& value) {
-  return fmt::internal::make_arg<Context>(value);
+  return fmt::detail::make_arg<Context>(value);
 }
 }  // namespace
 
@@ -84,26 +83,26 @@ TEST(BufferTest, Nonmoveable) {
 
 // A test buffer with a dummy grow method.
 template <typename T> struct test_buffer : buffer<T> {
-  void grow(std::size_t capacity) { this->set(nullptr, capacity); }
+  void grow(size_t capacity) { this->set(nullptr, capacity); }
 };
 
 template <typename T> struct mock_buffer : buffer<T> {
-  MOCK_METHOD1(do_grow, void(std::size_t capacity));
+  MOCK_METHOD1(do_grow, void(size_t capacity));
 
-  void grow(std::size_t capacity) {
+  void grow(size_t capacity) {
     this->set(this->data(), capacity);
     do_grow(capacity);
   }
 
   mock_buffer() {}
   mock_buffer(T* data) { this->set(data, 0); }
-  mock_buffer(T* data, std::size_t capacity) { this->set(data, capacity); }
+  mock_buffer(T* data, size_t capacity) { this->set(data, capacity); }
 };
 
 TEST(BufferTest, Ctor) {
   {
     mock_buffer<int> buffer;
-    EXPECT_EQ(nullptr, &buffer[0]);
+    EXPECT_EQ(nullptr, buffer.data());
     EXPECT_EQ(static_cast<size_t>(0), buffer.size());
     EXPECT_EQ(static_cast<size_t>(0), buffer.capacity());
   }
@@ -116,7 +115,7 @@ TEST(BufferTest, Ctor) {
   }
   {
     int dummy;
-    std::size_t capacity = std::numeric_limits<std::size_t>::max();
+    size_t capacity = std::numeric_limits<size_t>::max();
     mock_buffer<int> buffer(&dummy, capacity);
     EXPECT_EQ(&dummy, &buffer[0]);
     EXPECT_EQ(static_cast<size_t>(0), buffer.size());
@@ -127,8 +126,13 @@ TEST(BufferTest, Ctor) {
 struct dying_buffer : test_buffer<int> {
   MOCK_METHOD0(die, void());
   ~dying_buffer() { die(); }
+
+ private:
+  virtual void avoid_weak_vtable();
 };
 
+void dying_buffer::avoid_weak_vtable() {}
+
 TEST(BufferTest, VirtualDtor) {
   typedef StrictMock<dying_buffer> stict_mock_buffer;
   stict_mock_buffer* mock_buffer = new stict_mock_buffer();
@@ -144,7 +148,7 @@ TEST(BufferTest, Access) {
   EXPECT_EQ(11, buffer[0]);
   buffer[3] = 42;
   EXPECT_EQ(42, *(&buffer[0] + 3));
-  const fmt::internal::buffer<char>& const_buffer = buffer;
+  const fmt::detail::buffer<char>& const_buffer = buffer;
   EXPECT_EQ(42, const_buffer[3]);
 }
 
@@ -206,7 +210,8 @@ TEST(ArgTest, FormatArgs) {
 }
 
 struct custom_context {
-  typedef char char_type;
+  using char_type = char;
+  using parse_context_type = fmt::format_parse_context;
 
   template <typename T> struct formatter_type {
     template <typename ParseContext>
@@ -229,20 +234,20 @@ struct custom_context {
 
 TEST(ArgTest, MakeValueWithCustomContext) {
   test_struct t;
-  fmt::internal::value<custom_context> arg(
-      fmt::internal::arg_mapper<custom_context>().map(t));
+  fmt::detail::value<custom_context> arg(
+      fmt::detail::arg_mapper<custom_context>().map(t));
   custom_context ctx = {false, fmt::format_parse_context("")};
   arg.custom.format(&t, ctx.parse_context(), ctx);
   EXPECT_TRUE(ctx.called);
 }
 
 FMT_BEGIN_NAMESPACE
-namespace internal {
+namespace detail {
 template <typename Char>
 bool operator==(custom_value<Char> lhs, custom_value<Char> rhs) {
   return lhs.value == rhs.value;
 }
-}  // namespace internal
+}  // namespace detail
 FMT_END_NAMESPACE
 
 // Use a unique result type to make sure that there are no undesirable
@@ -285,8 +290,6 @@ VISIT_TYPE(long, long long);
 VISIT_TYPE(unsigned long, unsigned long long);
 #endif
 
-VISIT_TYPE(float, double);
-
 #define CHECK_ARG_(Char, expected, value)                                     \
   {                                                                           \
     testing::StrictMock<mock_visitor<decltype(expected)>> visitor;            \
@@ -369,12 +372,12 @@ TEST(ArgTest, PointerArg) {
 struct check_custom {
   test_result operator()(
       fmt::basic_format_arg<fmt::format_context>::handle h) const {
-    struct test_buffer : fmt::internal::buffer<char> {
+    struct test_buffer : fmt::detail::buffer<char> {
       char data[10];
-      test_buffer() : fmt::internal::buffer<char>(data, 0, 10) {}
-      void grow(std::size_t) {}
+      test_buffer() : fmt::detail::buffer<char>(data, 0, 10) {}
+      void grow(size_t) {}
     } buffer;
-    fmt::internal::buffer<char>& base = buffer;
+    fmt::detail::buffer<char>& base = buffer;
     fmt::format_parse_context parse_ctx("");
     fmt::format_context ctx(std::back_inserter(base), fmt::format_args());
     h.format(parse_ctx, ctx);
@@ -399,8 +402,174 @@ TEST(ArgTest, VisitInvalidArg) {
   fmt::visit_format_arg(visitor, arg);
 }
 
+TEST(FormatDynArgsTest, Basic) {
+  fmt::dynamic_format_arg_store<fmt::format_context> store;
+  store.push_back(42);
+  store.push_back("abc1");
+  store.push_back(1.5f);
+
+  std::string result = fmt::vformat("{} and {} and {}", store);
+  EXPECT_EQ("42 and abc1 and 1.5", result);
+}
+
+TEST(FormatDynArgsTest, StringsAndRefs) {
+  // 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';
+
+  std::string 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 format_to(ctx.out(), "cust={}", p.i);
+  }
+};
+FMT_END_NAMESPACE
+
+TEST(FormatDynArgsTest, CustomFormat) {
+  fmt::dynamic_format_arg_store<fmt::format_context> store;
+  custom_type c{};
+  store.push_back(c);
+  ++c.i;
+  store.push_back(c);
+  ++c.i;
+  store.push_back(std::cref(c));
+  ++c.i;
+
+  std::string result = fmt::vformat("{} and {} and {}", store);
+  EXPECT_EQ("cust=0 and cust=1 and cust=3", result);
+}
+
+TEST(FormatDynArgsTest, NamedInt) {
+  fmt::dynamic_format_arg_store<fmt::format_context> store;
+  store.push_back(fmt::arg("a1", 42));
+  std::string result = fmt::vformat("{a1}", store);
+  EXPECT_EQ("42", result);
+}
+
+TEST(FormatDynArgsTest, NamedStrings) {
+  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';
+
+  std::string result = fmt::vformat("{a1} and {a2}", store);
+
+  EXPECT_EQ("1234567890 and X234567890", result);
+}
+
+TEST(FormatDynArgsTest, NamedArgByRef) {
+  fmt::dynamic_format_arg_store<fmt::format_context> store;
+
+  // Note: fmt::arg() constructs an object which holds a reference
+  // to its value. It's not an aggregate, so it doesn't extend the
+  // reference lifetime. As a result, it's a very bad idea passing temporary
+  // as a named argument value. Only GCC with optimization level >0
+  // complains about this.
+  //
+  // A real life usecase is when you have both name and value alive
+  // guarantee their lifetime and thus don't want them to be copied into
+  // storages.
+  int a1_val{42};
+  auto a1 = fmt::arg("a1_", a1_val);
+  store.push_back("abc");
+  store.push_back(1.5f);
+  store.push_back(std::cref(a1));
+
+  std::string result = fmt::vformat("{a1_} and {} and {} and {}", store);
+
+  EXPECT_EQ("42 and abc and 1.5 and 42", result);
+}
+
+TEST(FormatDynArgsTest, NamedCustomFormat) {
+  fmt::dynamic_format_arg_store<fmt::format_context> store;
+  custom_type c{};
+  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;
+
+  std::string result = fmt::vformat("{c1} and {c2} and {c_ref}", store);
+  EXPECT_EQ("cust=0 and cust=1 and cust=3", result);
+}
+
+TEST(FormatDynArgsTest, Clear) {
+  fmt::dynamic_format_arg_store<fmt::format_context> store;
+  store.push_back(42);
+
+  std::string 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(FormatDynArgsTest, 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));
+  std::string 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(FormatDynArgsTest, ThrowOnCopy) {
+  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(StringViewTest, ValueType) {
+  static_assert(std::is_same<string_view::value_type, char>::value, "");
+}
+
 TEST(StringViewTest, Length) {
-  // Test that StringRef::size() returns string length, not buffer size.
+  // Test that string_view::size() returns string length, not buffer size.
   char str[100] = "some string";
   EXPECT_EQ(std::strlen(str), string_view(str).size());
   EXPECT_LT(std::strlen(str), sizeof(str));
@@ -409,9 +578,9 @@ TEST(StringViewTest, Length) {
 // Check string_view's comparison operator.
 template <template <typename> class Op> void check_op() {
   const char* inputs[] = {"foo", "fop", "fo"};
-  std::size_t num_inputs = sizeof(inputs) / sizeof(*inputs);
-  for (std::size_t i = 0; i < num_inputs; ++i) {
-    for (std::size_t j = 0; j < num_inputs; ++j) {
+  size_t num_inputs = sizeof(inputs) / sizeof(*inputs);
+  for (size_t i = 0; i < num_inputs; ++i) {
+    for (size_t j = 0; j < num_inputs; ++j) {
       string_view lhs(inputs[i]), rhs(inputs[j]);
       EXPECT_EQ(Op<int>()(lhs.compare(rhs), 0), Op<string_view>()(lhs, rhs));
     }
@@ -450,17 +619,22 @@ template <> struct formatter<enabled_formatter> {
 FMT_END_NAMESPACE
 
 TEST(CoreTest, HasFormatter) {
-  using fmt::internal::has_formatter;
+  using fmt::has_formatter;
   using context = fmt::format_context;
-  EXPECT_TRUE((has_formatter<enabled_formatter, context>::value));
-  EXPECT_FALSE((has_formatter<disabled_formatter, context>::value));
-  EXPECT_FALSE((has_formatter<disabled_formatter_convertible, context>::value));
+  static_assert(has_formatter<enabled_formatter, context>::value, "");
+  static_assert(!has_formatter<disabled_formatter, context>::value, "");
+  static_assert(!has_formatter<disabled_formatter_convertible, context>::value,
+                "");
 }
 
 struct convertible_to_int {
   operator int() const { return 42; }
 };
 
+struct convertible_to_c_string {
+  operator const char*() const { return "foo"; }
+};
+
 FMT_BEGIN_NAMESPACE
 template <> struct formatter<convertible_to_int> {
   auto parse(format_parse_context& ctx) -> decltype(ctx.begin()) {
@@ -470,10 +644,21 @@ template <> struct formatter<convertible_to_int> {
     return std::copy_n("foo", 3, ctx.out());
   }
 };
+
+template <> struct formatter<convertible_to_c_string> {
+  auto parse(format_parse_context& ctx) -> decltype(ctx.begin()) {
+    return ctx.begin();
+  }
+  auto format(convertible_to_c_string, format_context& ctx)
+      -> decltype(ctx.out()) {
+    return std::copy_n("bar", 3, ctx.out());
+  }
+};
 FMT_END_NAMESPACE
 
 TEST(CoreTest, FormatterOverridesImplicitConversion) {
   EXPECT_EQ(fmt::format("{}", convertible_to_int()), "foo");
+  EXPECT_EQ(fmt::format("{}", convertible_to_c_string()), "bar");
 }
 
 namespace my_ns {
@@ -481,7 +666,7 @@ template <typename Char> class my_string {
  public:
   my_string(const Char* s) : s_(s) {}
   const Char* data() const FMT_NOEXCEPT { return s_.data(); }
-  std::size_t length() const FMT_NOEXCEPT { return s_.size(); }
+  size_t length() const FMT_NOEXCEPT { return s_.size(); }
   operator const Char*() const { return s_.c_str(); }
 
  private:
@@ -497,23 +682,6 @@ inline fmt::basic_string_view<Char> to_string_view(const my_string<Char>& s)
 struct non_string {};
 }  // namespace my_ns
 
-namespace FakeQt {
-class QString {
- public:
-  QString(const wchar_t* s) : s_(std::make_shared<std::wstring>(s)) {}
-  const wchar_t* utf16() const FMT_NOEXCEPT { return s_->data(); }
-  int size() const FMT_NOEXCEPT { return static_cast<int>(s_->size()); }
-
- private:
-  std::shared_ptr<std::wstring> s_;
-};
-
-inline fmt::basic_string_view<wchar_t> to_string_view(const QString& s)
-    FMT_NOEXCEPT {
-  return {s.utf16(), static_cast<std::size_t>(s.size())};
-}
-}  // namespace FakeQt
-
 template <typename T> class IsStringTest : public testing::Test {};
 
 typedef ::testing::Types<char, wchar_t, char16_t, char32_t> StringCharTypes;
@@ -525,21 +693,19 @@ struct derived_from_string_view : fmt::basic_string_view<Char> {};
 }  // namespace
 
 TYPED_TEST(IsStringTest, IsString) {
-  EXPECT_TRUE(fmt::internal::is_string<TypeParam*>::value);
-  EXPECT_TRUE(fmt::internal::is_string<const TypeParam*>::value);
-  EXPECT_TRUE(fmt::internal::is_string<TypeParam[2]>::value);
-  EXPECT_TRUE(fmt::internal::is_string<const TypeParam[2]>::value);
-  EXPECT_TRUE(fmt::internal::is_string<std::basic_string<TypeParam>>::value);
+  EXPECT_TRUE(fmt::detail::is_string<TypeParam*>::value);
+  EXPECT_TRUE(fmt::detail::is_string<const TypeParam*>::value);
+  EXPECT_TRUE(fmt::detail::is_string<TypeParam[2]>::value);
+  EXPECT_TRUE(fmt::detail::is_string<const TypeParam[2]>::value);
+  EXPECT_TRUE(fmt::detail::is_string<std::basic_string<TypeParam>>::value);
+  EXPECT_TRUE(fmt::detail::is_string<fmt::basic_string_view<TypeParam>>::value);
   EXPECT_TRUE(
-      fmt::internal::is_string<fmt::basic_string_view<TypeParam>>::value);
-  EXPECT_TRUE(
-      fmt::internal::is_string<derived_from_string_view<TypeParam>>::value);
-  using string_view = fmt::internal::std_string_view<TypeParam>;
+      fmt::detail::is_string<derived_from_string_view<TypeParam>>::value);
+  using string_view = fmt::detail::std_string_view<TypeParam>;
   EXPECT_TRUE(std::is_empty<string_view>::value !=
-              fmt::internal::is_string<string_view>::value);
-  EXPECT_TRUE(fmt::internal::is_string<my_ns::my_string<TypeParam>>::value);
-  EXPECT_FALSE(fmt::internal::is_string<my_ns::non_string>::value);
-  EXPECT_TRUE(fmt::internal::is_string<FakeQt::QString>::value);
+              fmt::detail::is_string<string_view>::value);
+  EXPECT_TRUE(fmt::detail::is_string<my_ns::my_string<TypeParam>>::value);
+  EXPECT_FALSE(fmt::detail::is_string<my_ns::non_string>::value);
 }
 
 TEST(CoreTest, Format) {
@@ -562,33 +728,16 @@ TEST(CoreTest, FormatTo) {
 
 TEST(CoreTest, ToStringViewForeignStrings) {
   using namespace my_ns;
-  using namespace FakeQt;
   EXPECT_EQ(to_string_view(my_string<char>("42")), "42");
-  EXPECT_EQ(to_string_view(my_string<wchar_t>(L"42")), L"42");
-  EXPECT_EQ(to_string_view(QString(L"42")), L"42");
-  fmt::internal::type type =
-      fmt::internal::mapped_type_constant<my_string<char>,
-                                          fmt::format_context>::value;
-  EXPECT_EQ(type, fmt::internal::string_type);
-  type = fmt::internal::mapped_type_constant<my_string<wchar_t>,
-                                             fmt::wformat_context>::value;
-  EXPECT_EQ(type, fmt::internal::string_type);
-  type =
-      fmt::internal::mapped_type_constant<QString, fmt::wformat_context>::value;
-  EXPECT_EQ(type, fmt::internal::string_type);
-  // Does not compile: only wide format contexts are compatible with QString!
-  // type = fmt::internal::mapped_type_constant<QString,
-  // fmt::format_context>::value;
+  fmt::detail::type type =
+      fmt::detail::mapped_type_constant<my_string<char>,
+                                        fmt::format_context>::value;
+  EXPECT_EQ(type, fmt::detail::type::string_type);
 }
 
 TEST(CoreTest, FormatForeignStrings) {
   using namespace my_ns;
-  using namespace FakeQt;
   EXPECT_EQ(fmt::format(my_string<char>("{}"), 42), "42");
-  EXPECT_EQ(fmt::format(my_string<wchar_t>(L"{}"), 42), L"42");
-  EXPECT_EQ(fmt::format(QString(L"{}"), 42), L"42");
-  EXPECT_EQ(fmt::format(QString(L"{}"), my_string<wchar_t>(L"42")), L"42");
-  EXPECT_EQ(fmt::format(my_string<wchar_t>(L"{}"), QString(L"42")), L"42");
 }
 
 struct implicitly_convertible_to_string {
@@ -613,25 +762,25 @@ TEST(FormatterTest, FormatExplicitlyConvertibleToStringView) {
   EXPECT_EQ("foo", fmt::format("{}", explicitly_convertible_to_string_view()));
 }
 
-struct explicitly_convertible_to_wstring_view {
-  explicit operator fmt::wstring_view() const { return L"foo"; }
+#  ifdef FMT_USE_STRING_VIEW
+struct explicitly_convertible_to_std_string_view {
+  explicit operator std::string_view() const { return "foo"; }
 };
 
-TEST(FormatterTest, FormatExplicitlyConvertibleToWStringView) {
-  EXPECT_EQ(L"foo",
-            fmt::format(L"{}", explicitly_convertible_to_wstring_view()));
-}
-
-struct explicitly_convertible_to_string_like {
-  template <typename String,
-            typename = typename std::enable_if<std::is_constructible<
-                String, const char*, std::size_t>::value>::type>
-  explicit operator String() const {
-    return String("foo", 3u);
-  }
-};
-
-TEST(FormatterTest, FormatExplicitlyConvertibleToStringLike) {
-  EXPECT_EQ("foo", fmt::format("{}", explicitly_convertible_to_string_like()));
+TEST(FormatterTest, FormatExplicitlyConvertibleToStdStringView) {
+  EXPECT_EQ("foo",
+            fmt::format("{}", explicitly_convertible_to_std_string_view()));
 }
+#  endif
 #endif
+
+struct disabled_rvalue_conversion {
+  operator const char*() const& { return "foo"; }
+  operator const char*() & { return "foo"; }
+  operator const char*() const&& = delete;
+  operator const char*() && = delete;
+};
+
+TEST(FormatterTest, DisabledRValueConversion) {
+  EXPECT_EQ("foo", fmt::format("{}", disabled_rvalue_conversion()));
+}

test/custom-formatter-test.cc

@@ -18,14 +18,14 @@
 // A custom argument formatter that doesn't print `-` for floating-point values
 // rounded to 0.
 class custom_arg_formatter
-    : public fmt::arg_formatter<fmt::buffer_range<char>> {
+    : public fmt::detail::arg_formatter<fmt::format_context::iterator, char> {
  public:
-  using range = fmt::buffer_range<char>;
-  typedef fmt::arg_formatter<range> base;
+  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)
+                       fmt::format_specs* s = nullptr,
+                       const char* = nullptr)
       : base(ctx, parse_ctx, s) {}
 
   using base::operator();
@@ -39,8 +39,10 @@ class custom_arg_formatter
 
 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>(buffer, format_str, args);
+  fmt::vformat_to<custom_arg_formatter>(std::back_inserter(base), format_str,
+                                        args);
   return std::string(buffer.data(), buffer.size());
 }
 

test/format

@@ -8,6 +8,7 @@
 #ifndef FMT_FORMAT_
 #define FMT_FORMAT_
 
+#include <cassert>
 #include <variant>
 #include "fmt/format.h"
 
@@ -37,9 +38,9 @@ namespace std {
   
   template<class Out, class charT> class basic_format_context;
   using format_context = basic_format_context<
-    /* unspecified */ std::back_insert_iterator<fmt::internal::buffer<char>>, char>;
+    /* unspecified */ std::back_insert_iterator<fmt::detail::buffer<char>>, char>;
   using wformat_context = basic_format_context<
-    /* unspecified */ std::back_insert_iterator<fmt::internal::buffer<wchar_t>>, wchar_t>;
+    /* unspecified */ std::back_insert_iterator<fmt::detail::buffer<wchar_t>>, wchar_t>;
 
   template<class T, class charT = char> struct formatter {
     formatter() = delete;
@@ -82,9 +83,9 @@ namespace std {
     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<Out, char> args);
+    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<Out, wchar_t> args);
+    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 {
@@ -218,7 +219,7 @@ namespace std {
 
     // Implementation details:
     using format_arg = basic_format_arg<basic_format_context>;
-    basic_format_context(Out out, basic_format_args<basic_format_context> args, fmt::internal::locale_ref)
+    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 {
@@ -487,22 +488,21 @@ template<class... Args>
 namespace std {
 namespace detail {
 
-template <typename Range>
+template <typename OutputIt, typename Char>
 class arg_formatter
-    : public fmt::internal::arg_formatter_base<Range, error_handler> {
+    : public fmt::detail::arg_formatter_base<OutputIt, Char, error_handler> {
  private:
-  using char_type = typename Range::value_type;
-  using base = fmt::internal::arg_formatter_base<Range, error_handler>;
-  using format_context = std::basic_format_context<typename base::iterator, char_type>;
-  using parse_context = basic_format_parse_context<char_type>;
+  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:
-  typedef Range range;
-  typedef typename base::iterator iterator;
-  typedef typename base::format_specs format_specs;
+  using iterator = OutputIt;
+  using format_specs = typename base::format_specs;
 
   /**
     \rst
@@ -512,7 +512,7 @@ class arg_formatter
     \endrst
    */
   arg_formatter(format_context& ctx, parse_context* parse_ctx = nullptr, fmt::format_specs* spec = nullptr)
-      : base(Range(ctx.out()), spec, {}), parse_ctx_(parse_ctx), ctx_(ctx) {}
+      : base(ctx.out(), spec, {}), parse_ctx_(parse_ctx), ctx_(ctx) {}
 
   using base::operator();
 
@@ -528,36 +528,36 @@ class arg_formatter
 };
 
 template <typename Context>
-inline fmt::internal::type get_type(basic_format_arg<Context> arg) {
+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::internal::none_type;
+      return fmt::detail::type::none_type;
     if (std::is_same_v<T, bool>)
-      return fmt::internal::bool_type;
+      return fmt::detail::type::bool_type;
     if (std::is_same_v<T, char_type>)
-      return fmt::internal::char_type;
+      return fmt::detail::type::char_type;
     if (std::is_same_v<T, int>)
-      return fmt::internal::int_type;
+      return fmt::detail::type::int_type;
     if (std::is_same_v<T, unsigned int>)
-      return fmt::internal::uint_type;
+      return fmt::detail::type::uint_type;
     if (std::is_same_v<T, long long int>)
-      return fmt::internal::long_long_type;
+      return fmt::detail::type::long_long_type;
     if (std::is_same_v<T, unsigned long long int>)
-      return fmt::internal::ulong_long_type;
+      return fmt::detail::type::ulong_long_type;
     if (std::is_same_v<T, double>)
-      return fmt::internal::double_type;
+      return fmt::detail::type::double_type;
     if (std::is_same_v<T, long double>)
-      return fmt::internal::long_double_type;
+      return fmt::detail::type::long_double_type;
     if (std::is_same_v<T, const char_type*>)
-      return fmt::internal::cstring_type;
+      return fmt::detail::type::cstring_type;
     if (std::is_same_v<T, basic_string_view<char_type>>)
-      return fmt::internal::string_type;
+      return fmt::detail::type::string_type;
     if (std::is_same_v<T, const void*>)
-      return fmt::internal::pointer_type;
+      return fmt::detail::type::pointer_type;
     assert(get_value(arg).index() == 12);
-    return fmt::internal::custom_type;
+    return fmt::detail::type::custom_type;
   }, arg);
 }
 
@@ -581,45 +581,42 @@ class custom_formatter {
 
 template <typename ArgFormatter, typename Char, typename Context>
 struct format_handler : detail::error_handler {
-  typedef typename ArgFormatter::range range;
+  using iterator = typename ArgFormatter::iterator;
 
-  format_handler(range r, basic_string_view<Char> str,
+  format_handler(iterator out, basic_string_view<Char> str,
                  basic_format_args<Context> format_args,
-                 fmt::internal::locale_ref loc)
-      : parse_ctx(str), context(r.begin(), format_args, loc) {}
+                 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::internal::to_unsigned(end - begin);
+    auto size = fmt::detail::to_unsigned(end - begin);
     auto out = context.out();
-    auto&& it = fmt::internal::reserve(out, size);
+    auto&& it = fmt::detail::reserve(out, size);
     it = std::copy_n(begin, size, it);
     context.advance_to(out);
   }
 
-  void on_arg_id() {
-    arg = context.arg(parse_ctx.next_arg_id());
-  }
-  void on_arg_id(unsigned id) {
-    parse_ctx.check_arg_id(id);
-    arg = context.arg(id);
-  }
-  void on_arg_id(fmt::basic_string_view<Char>) {}
+  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(const Char* p) {
-    parse_ctx.advance_to(parse_ctx.begin() + (p - &*parse_ctx.begin()));
+  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(const Char* begin, const Char* end) {
+  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::internal::specs_handler;
+    using fmt::detail::specs_handler;
     using parse_context = basic_format_parse_context<Char>;
-    fmt::internal::specs_checker<specs_handler<parse_context, Context>> handler(
+    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");
@@ -630,7 +627,6 @@ struct format_handler : detail::error_handler {
 
   basic_format_parse_context<Char> parse_ctx;
   Context context;
-  basic_format_arg<Context> arg;
 };
 
 template <typename T, typename Char>
@@ -639,47 +635,45 @@ struct formatter {
   // terminating '}'.
   template <typename ParseContext>
   FMT_CONSTEXPR typename ParseContext::iterator parse(ParseContext& ctx) {
-    namespace internal = fmt::internal;
-    typedef internal::dynamic_specs_handler<ParseContext> handler_type;
-    auto type = internal::mapped_type_constant<T, fmt::buffer_context<Char>>::value;
-    internal::specs_checker<handler_type> handler(handler_type(specs_, 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 internal::none_type:
-    case internal::named_arg_type:
+    case detail::type::none_type:
       FMT_ASSERT(false, "invalid argument type");
       break;
-    case internal::int_type:
-    case internal::uint_type:
-    case internal::long_long_type:
-    case internal::ulong_long_type:
-    case internal::bool_type:
+    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,
-                           internal::int_type_checker<decltype(eh)>(eh));
+                           detail::int_type_checker<decltype(eh)>(eh));
       break;
-    case internal::char_type:
+    case detail::type::char_type:
       handle_char_specs(
-          &specs_, internal::char_specs_checker<decltype(eh)>(type_spec, eh));
+          &specs_, detail::char_specs_checker<decltype(eh)>(type_spec, eh));
       break;
-    case internal::double_type:
-    case internal::long_double_type:
-      handle_float_type_spec(type_spec,
-                             internal::float_type_checker<decltype(eh)>(eh));
+    case detail::type::double_type:
+    case detail::type::long_double_type:
+      detail::parse_float_type_spec(specs_, eh);
       break;
-    case internal::cstring_type:
-      internal::handle_cstring_type_spec(
-          type_spec, internal::cstring_type_checker<decltype(eh)>(eh));
+    case detail::type::cstring_type:
+      detail::handle_cstring_type_spec(
+          type_spec, detail::cstring_type_checker<decltype(eh)>(eh));
       break;
-    case internal::string_type:
-      internal::check_string_type_spec(type_spec, eh);
+    case detail::type::string_type:
+      detail::check_string_type_spec(type_spec, eh);
       break;
-    case internal::pointer_type:
-      internal::check_pointer_type_spec(type_spec, eh);
+    case detail::type::pointer_type:
+      detail::check_pointer_type_spec(type_spec, eh);
       break;
-    case internal::custom_type:
+    case detail::type::custom_type:
       // Custom format specifiers should be checked in parse functions of
       // formatter specializations.
       break;
@@ -689,18 +683,18 @@ struct formatter {
 
   template <typename FormatContext>
   auto format(const T& val, FormatContext& ctx) -> decltype(ctx.out()) {
-    fmt::internal::handle_dynamic_spec<fmt::internal::width_checker>(
+    fmt::detail::handle_dynamic_spec<fmt::detail::width_checker>(
         specs_.width, specs_.width_ref, ctx);
-    fmt::internal::handle_dynamic_spec<fmt::internal::precision_checker>(
+    fmt::detail::handle_dynamic_spec<fmt::detail::precision_checker>(
         specs_.precision, specs_.precision_ref, ctx);
-    using range_type = fmt::internal::output_range<typename FormatContext::iterator,
-                         typename FormatContext::char_type>;
-    return visit_format_arg(arg_formatter<range_type>(ctx, nullptr, &specs_),
+    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::internal::dynamic_format_specs<Char> specs_;
+  fmt::detail::dynamic_format_specs<Char> specs_;
 };
 }  // namespace detail
 
@@ -717,11 +711,11 @@ template<class... Args>
 
 string vformat(string_view fmt, format_args args) {
   fmt::memory_buffer mbuf;
-  fmt::internal::buffer<char>& buf = mbuf;
-  using range = fmt::buffer_range<char>;
-  detail::format_handler<detail::arg_formatter<range>, char, format_context>
-    h(range(std::back_inserter(buf)), fmt, args, {});
-  fmt::internal::parse_format_string<false>(fmt::to_string_view(fmt), h);
+  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);
 }
 
@@ -730,26 +724,26 @@ 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...)});
+    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...)});
+    return vformat_to(out, fmt, make_format_args<context>(args...));
   }
 
 template<class Out>
-  Out vformat_to(Out out, string_view fmt, format_args_t<Out, char> args) {
-    using range = fmt::internal::output_range<Out, char>;
-    detail::format_handler<detail::arg_formatter<range>, char, basic_format_context<Out, char>>
-      h(range(out), fmt, args, {});
-    fmt::internal::parse_format_string<false>(fmt::to_string_view(fmt), h);
+  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<Out, wchar_t> args);
+  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,

test/format-dyn-args-test.cc

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

test/format-impl-test.cc

@@ -10,21 +10,20 @@
 #include "test-assert.h"
 
 // Include format.cc instead of format.h to test implementation.
-#include "../src/format.cc"
-#include "fmt/printf.h"
-
 #include <algorithm>
 #include <cstring>
 
+#include "../src/format.cc"
+#include "fmt/printf.h"
 #include "gmock.h"
 #include "gtest-extra.h"
 #include "util.h"
 
 #undef max
 
-using fmt::internal::bigint;
-using fmt::internal::fp;
-using fmt::internal::max_value;
+using fmt::detail::bigint;
+using fmt::detail::fp;
+using fmt::detail::max_value;
 
 static_assert(!std::is_copy_constructible<bigint>::value, "");
 static_assert(!std::is_copy_assignable<bigint>::value, "");
@@ -35,6 +34,46 @@ TEST(BigIntTest, Construct) {
   EXPECT_EQ("123456789abcedf0", fmt::format("{}", bigint(0x123456789abcedf0)));
 }
 
+TEST(BigIntTest, Compare) {
+  bigint n1(42);
+  bigint n2(42);
+  EXPECT_EQ(compare(n1, n2), 0);
+  n2 <<= 32;
+  EXPECT_LT(compare(n1, n2), 0);
+  bigint n3(43);
+  EXPECT_LT(compare(n1, n3), 0);
+  EXPECT_GT(compare(n3, n1), 0);
+  bigint n4(42 * 0x100000001);
+  EXPECT_LT(compare(n2, n4), 0);
+  EXPECT_GT(compare(n4, n2), 0);
+}
+
+TEST(BigIntTest, AddCompare) {
+  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);
+  EXPECT_GT(add_compare(bigint(1) <<= 32, bigint(0), bigint(0xffffffff)), 0);
+  EXPECT_GT(add_compare(bigint(0), bigint(1) <<= 32, bigint(0xffffffff)), 0);
+  EXPECT_GT(add_compare(bigint(42), bigint(1), bigint(42)), 0);
+  EXPECT_GT(add_compare(bigint(0xffffffff), bigint(1), bigint(0xffffffff)), 0);
+  EXPECT_LT(add_compare(bigint(10), bigint(10), bigint(22)), 0);
+  EXPECT_LT(add_compare(bigint(0x100000010), bigint(0x100000010),
+                        bigint(0x300000010)),
+            0);
+  EXPECT_GT(add_compare(bigint(0x1ffffffff), bigint(0x100000002),
+                        bigint(0x300000000)),
+            0);
+  EXPECT_EQ(add_compare(bigint(0x1ffffffff), bigint(0x100000002),
+                        bigint(0x300000001)),
+            0);
+  EXPECT_LT(add_compare(bigint(0x1ffffffff), bigint(0x100000002),
+                        bigint(0x300000002)),
+            0);
+  EXPECT_LT(add_compare(bigint(0x1ffffffff), bigint(0x100000002),
+                        bigint(0x300000003)),
+            0);
+}
+
 TEST(BigIntTest, ShiftLeft) {
   bigint n(0x42);
   n <<= 0;
@@ -47,30 +86,133 @@ TEST(BigIntTest, ShiftLeft) {
 
 TEST(BigIntTest, Multiply) {
   bigint n(0x42);
+  EXPECT_THROW(n *= 0, assertion_failure);
   n *= 1;
   EXPECT_EQ("42", fmt::format("{}", n));
   n *= 2;
   EXPECT_EQ("84", fmt::format("{}", n));
   n *= 0x12345678;
   EXPECT_EQ("962fc95e0", fmt::format("{}", n));
-  auto max = max_value<uint32_t>();
-  bigint bigmax(max);
-  bigmax *= max;
+  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));
 }
 
-template <bool is_iec559> void test_construct_from_double() {
+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) {
+  bigint n0(0);
+  n0.square();
+  EXPECT_EQ("0", fmt::format("{}", n0));
+  bigint n1(0x100);
+  n1.square();
+  EXPECT_EQ("10000", fmt::format("{}", n1));
+  bigint n2(0xfffffffff);
+  n2.square();
+  EXPECT_EQ("ffffffffe000000001", fmt::format("{}", n2));
+  bigint n3(max_value<uint64_t>());
+  n3.square();
+  EXPECT_EQ("fffffffffffffffe0000000000000001", fmt::format("{}", n3));
+  bigint n4;
+  n4.assign_pow10(10);
+  EXPECT_EQ("2540be400", fmt::format("{}", n4));
+}
+
+TEST(BigIntTest, DivModAssignZeroDivisor) {
+  bigint zero(0);
+  EXPECT_THROW(bigint(0).divmod_assign(zero), assertion_failure);
+  EXPECT_THROW(bigint(42).divmod_assign(zero), assertion_failure);
+}
+
+TEST(BigIntTest, DivModAssignSelf) {
+  bigint n(100);
+  EXPECT_THROW(n.divmod_assign(n), assertion_failure);
+}
+
+TEST(BigIntTest, DivModAssignUnaligned) {
+  // (42 << 340) / pow(10, 100):
+  bigint n1(42);
+  n1 <<= 340;
+  bigint n2;
+  n2.assign_pow10(100);
+  int result = n1.divmod_assign(n2);
+  EXPECT_EQ(result, 9406);
+  EXPECT_EQ("10f8353019583bfc29ffc8f564e1b9f9d819dbb4cf783e4507eca1539220p96",
+            fmt::format("{}", n1));
+}
+
+TEST(BigIntTest, DivModAssign) {
+  // 100 / 10:
+  bigint n1(100);
+  int result = n1.divmod_assign(bigint(10));
+  EXPECT_EQ(result, 10);
+  EXPECT_EQ("0", fmt::format("{}", n1));
+  // 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));
+  // 42 / 100:
+  bigint n2(42);
+  n1.assign_pow10(2);
+  result = n2.divmod_assign(n1);
+  EXPECT_EQ(result, 0);
+  EXPECT_EQ("2a", fmt::format("{}", n2));
+}
+
+template <bool is_iec559> void run_double_tests() {
   fmt::print("warning: double is not IEC559, skipping FP tests\n");
 }
 
-template <> void test_construct_from_double<true>() {
-  auto v = fp(1.23);
-  EXPECT_EQ(v.f, 0x13ae147ae147aeu);
-  EXPECT_EQ(v.e, -52);
+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, ConstructFromDouble) {
-  test_construct_from_double<std::numeric_limits<double>::is_iec559>();
+TEST(FPTest, DoubleTests) {
+  run_double_tests<std::numeric_limits<double>::is_iec559>();
 }
 
 TEST(FPTest, Normalize) {
@@ -80,30 +222,31 @@ TEST(FPTest, Normalize) {
   EXPECT_EQ(-6, normalized.e);
 }
 
-TEST(FPTest, ComputeBoundariesSubnormal) {
-  auto v = fp(0xbeef, 42);
-  fp lower, upper;
-  v.compute_boundaries(lower, upper);
-  EXPECT_EQ(0xbeee800000000000, lower.f);
-  EXPECT_EQ(-6, lower.e);
-  EXPECT_EQ(0xbeef800000000000, upper.f);
-  EXPECT_EQ(-6, upper.e);
-}
-
-TEST(FPTest, ComputeBoundaries) {
-  auto v = fp(0x10000000000000, 42);
-  fp lower, upper;
-  v.compute_boundaries(lower, upper);
-  EXPECT_EQ(0x7ffffffffffffe00, lower.f);
-  EXPECT_EQ(31, lower.e);
-  EXPECT_EQ(0x8000000000000400, upper.f);
-  EXPECT_EQ(31, upper.e);
-}
-
-TEST(FPTest, Subtract) {
-  auto v = fp(123, 1) - fp(102, 1);
-  EXPECT_EQ(v.f, 21u);
-  EXPECT_EQ(v.e, 1);
+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) {
@@ -119,7 +262,7 @@ 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::internal::get_cached_power(exp, dec_exp);
+    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));
@@ -128,32 +271,33 @@ TEST(FPTest, GetCachedPower) {
 }
 
 TEST(FPTest, GetRoundDirection) {
-  using fmt::internal::get_round_direction;
-  EXPECT_EQ(fmt::internal::down, get_round_direction(100, 50, 0));
-  EXPECT_EQ(fmt::internal::up, get_round_direction(100, 51, 0));
-  EXPECT_EQ(fmt::internal::down, get_round_direction(100, 40, 10));
-  EXPECT_EQ(fmt::internal::up, get_round_direction(100, 60, 10));
-  for (int i = 41; i < 60; ++i)
-    EXPECT_EQ(fmt::internal::unknown, get_round_direction(100, i, 10));
+  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(fmt::internal::up, get_round_direction(max, max - 1, 2));
+  EXPECT_EQ(round_direction::up, get_round_direction(max, max - 1, 2));
   // Check that 2 * (remainder + error) doesn't overflow.
-  EXPECT_EQ(fmt::internal::unknown,
+  EXPECT_EQ(round_direction::unknown,
             get_round_direction(max, max / 2 + 1, max / 2));
   // Check that remainder - error doesn't overflow.
-  EXPECT_EQ(fmt::internal::unknown, get_round_direction(100, 40, 41));
+  EXPECT_EQ(round_direction::unknown, get_round_direction(100, 40, 41));
   // Check that 2 * (remainder - error) doesn't overflow.
-  EXPECT_EQ(fmt::internal::up, get_round_direction(max, max - 1, 1));
+  EXPECT_EQ(round_direction::up, get_round_direction(max, max - 1, 1));
 }
 
 TEST(FPTest, FixedHandler) {
-  struct handler : fmt::internal::fixed_handler {
+  struct handler : fmt::detail::fixed_handler {
     char buffer[10];
-    handler(int prec = 0) : fmt::internal::fixed_handler() {
+    handler(int prec = 0) : fmt::detail::fixed_handler() {
       buf = buffer;
       precision = prec;
     }
@@ -162,7 +306,7 @@ TEST(FPTest, FixedHandler) {
   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::internal::digits;
+  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);
@@ -174,8 +318,7 @@ TEST(FPTest, FixedHandler) {
 
 TEST(FPTest, GrisuFormatCompilesWithNonIEEEDouble) {
   fmt::memory_buffer buf;
-  int exp = 0;
-  grisu_format(4.2f, buf, -1, false, exp);
+  format_float(0.42, -1, fmt::detail::float_specs(), buf);
 }
 
 template <typename T> struct value_extractor {
@@ -185,23 +328,23 @@ template <typename T> struct value_extractor {
     throw std::runtime_error(fmt::format("invalid type {}", typeid(U).name()));
   }
 
-#ifdef __apple_build_version__
+#if FMT_USE_INT128
   // Apple Clang does not define typeid for __int128_t and __uint128_t.
-  FMT_NORETURN T operator()(__int128_t) {
-    throw std::runtime_error(fmt::format("invalid type {}", "__int128_t"));
+  FMT_NORETURN T operator()(fmt::detail::int128_t) {
+    throw std::runtime_error("invalid type __int128_t");
   }
 
-  FMT_NORETURN T operator()(__uint128_t) {
-    throw std::runtime_error(fmt::format("invalid type {}", "__uint128_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::internal::make_arg<fmt::format_context>(value);
+  auto arg = fmt::detail::make_arg<fmt::format_context>(value);
   fmt::visit_format_arg(
-      fmt::internal::arg_converter<long long, fmt::format_context>(arg, 'd'),
+      fmt::detail::arg_converter<long long, fmt::format_context>(arg, 'd'),
       arg);
   EXPECT_EQ(value, fmt::visit_format_arg(value_extractor<long long>(), arg));
 }
@@ -217,9 +360,9 @@ TEST(FormatTest, FormatNegativeNaN) {
 TEST(FormatTest, StrError) {
   char* message = nullptr;
   char buffer[BUFFER_SIZE];
-  EXPECT_ASSERT(fmt::internal::safe_strerror(EDOM, message = nullptr, 0),
+  EXPECT_ASSERT(fmt::detail::safe_strerror(EDOM, message = nullptr, 0),
                 "invalid buffer");
-  EXPECT_ASSERT(fmt::internal::safe_strerror(EDOM, message = buffer, 0),
+  EXPECT_ASSERT(fmt::detail::safe_strerror(EDOM, message = buffer, 0),
                 "invalid buffer");
   buffer[0] = 'x';
 #if defined(_GNU_SOURCE) && !defined(__COVERITY__)
@@ -231,18 +374,18 @@ TEST(FormatTest, StrError) {
 #endif
 
   int result =
-      fmt::internal::safe_strerror(error_code, message = buffer, BUFFER_SIZE);
+      fmt::detail::safe_strerror(error_code, message = buffer, BUFFER_SIZE);
   EXPECT_EQ(result, 0);
-  std::size_t message_size = std::strlen(message);
+  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::internal::safe_strerror(error_code, message = buffer, message_size);
+      fmt::detail::safe_strerror(error_code, message = buffer, message_size);
   EXPECT_EQ(ERANGE, result);
-  result = fmt::internal::safe_strerror(error_code, message = buffer, 1);
+  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);
@@ -254,46 +397,48 @@ TEST(FormatTest, FormatErrorCode) {
   {
     fmt::memory_buffer buffer;
     format_to(buffer, "garbage");
-    fmt::internal::format_error_code(buffer, 42, "test");
+    fmt::detail::format_error_code(buffer, 42, "test");
     EXPECT_EQ("test: " + msg, to_string(buffer));
   }
   {
     fmt::memory_buffer buffer;
     std::string prefix(fmt::inline_buffer_size - msg.size() - sep.size() + 1,
                        'x');
-    fmt::internal::format_error_code(buffer, 42, prefix);
+    fmt::detail::format_error_code(buffer, 42, prefix);
     EXPECT_EQ(msg, to_string(buffer));
   }
   int codes[] = {42, -1};
-  for (std::size_t i = 0, n = sizeof(codes) / sizeof(*codes); i < n; ++i) {
+  for (size_t i = 0, n = sizeof(codes) / sizeof(*codes); i < n; ++i) {
     // 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');
-    fmt::internal::format_error_code(buffer, codes[i], prefix);
+    fmt::detail::format_error_code(buffer, codes[i], prefix);
     EXPECT_EQ(prefix + sep + msg, to_string(buffer));
-    std::size_t size = fmt::inline_buffer_size;
+    size_t size = fmt::inline_buffer_size;
     EXPECT_EQ(size, buffer.size());
     buffer.resize(0);
     // Test with a message that doesn't fit into the buffer.
     prefix += 'x';
-    fmt::internal::format_error_code(buffer, codes[i], prefix);
+    fmt::detail::format_error_code(buffer, codes[i], prefix);
     EXPECT_EQ(msg, to_string(buffer));
   }
 }
 
 TEST(FormatTest, CountCodePoints) {
-  EXPECT_EQ(4, fmt::internal::count_code_points(fmt::u8string_view("ёжик")));
+  EXPECT_EQ(4,
+            fmt::detail::count_code_points(
+                fmt::basic_string_view<fmt::detail::char8_type>(
+                    reinterpret_cast<const fmt::detail::char8_type*>("ёжик"))));
 }
 
-// Tests fmt::internal::count_digits for integer type Int.
+// Tests fmt::detail::count_digits for integer type Int.
 template <typename Int> void test_count_digits() {
-  for (Int i = 0; i < 10; ++i) EXPECT_EQ(1u, fmt::internal::count_digits(i));
-  for (Int i = 1, n = 1, end = max_value<Int>() / 10; n <= end;
-       ++i) {
+  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::internal::count_digits(n - 1));
-    EXPECT_EQ(i + 1, fmt::internal::count_digits(n));
+    EXPECT_EQ(i, fmt::detail::count_digits(n - 1));
+    EXPECT_EQ(i + 1, fmt::detail::count_digits(n));
   }
 }
 
@@ -302,11 +447,10 @@ TEST(UtilTest, CountDigits) {
   test_count_digits<uint64_t>();
 }
 
-TEST(UtilTest, WriteUIntPtr) {
-  fmt::memory_buffer buf;
-  fmt::internal::writer writer(buf);
-  writer.write_pointer(fmt::internal::bit_cast<fmt::internal::fallback_uintptr>(
-                           reinterpret_cast<void*>(0xface)),
-                       nullptr);
-  EXPECT_EQ("0xface", to_string(buf));
+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/fuzzing/README.md

@@ -7,14 +7,19 @@ in fmt. It is a part of the continous fuzzing at
 The source code is modified to make the fuzzing possible without locking up on
 resource exhaustion:
 ```cpp
-#ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
+#ifdef FMT_FUZZ
 if(spec.precision>100000) {
   throw std::runtime_error("fuzz mode - avoiding large precision");
 }
 #endif
-```
-This macro is the defacto standard for making fuzzing practically possible, see
-[the libFuzzer documentation](https://llvm.org/docs/LibFuzzer.html#fuzzer-friendly-build-mode).
+``` 
+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
 

test/fuzzing/chrono_duration.cpp

@@ -25,7 +25,7 @@ void invoke_inner(fmt::string_view formatstring, const Item item) {
 
 // Item is the underlying type for duration (int, long etc)
 template <typename Item>
-void invoke_outer(const uint8_t* Data, std::size_t Size, const int scaling) {
+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;
 
@@ -97,7 +97,7 @@ void invoke_outer(const uint8_t* Data, std::size_t Size, const int scaling) {
   // doit_impl<Item,std::yotta>(buf.data(),item);
 }
 
-extern "C" int LLVMFuzzerTestOneInput(const uint8_t* Data, std::size_t Size) {
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t* Data, size_t Size) {
   if (Size <= 4) {
     return 0;
   }

test/fuzzing/main.cpp

@@ -4,7 +4,7 @@
 #include <vector>
 #include "fuzzer_common.h"
 
-extern "C" int LLVMFuzzerTestOneInput(const uint8_t* Data, std::size_t Size);
+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]);
@@ -13,7 +13,7 @@ int main(int argc, char* argv[]) {
     const auto pos = in.tellg();
     assert(pos >= 0);
     in.seekg(0, std::ios_base::beg);
-    std::vector<char> buf(static_cast<std::size_t>(pos));
+    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.cpp

@@ -10,7 +10,7 @@
 #include "fuzzer_common.h"
 
 template <typename Item1>
-void invoke_fmt(const uint8_t* Data, std::size_t Size, unsigned int argsize) {
+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) {
@@ -29,11 +29,11 @@ void invoke_fmt(const uint8_t* Data, std::size_t Size, unsigned int argsize) {
   // allocating buffers separately is slower, but increases chances
   // of detecting memory errors
 #if FMT_FUZZ_SEPARATE_ALLOCATION
-  std::vector<char> argnamebuffer(argsize);
+  std::vector<char> argnamebuffer(argsize + 1);
   std::memcpy(argnamebuffer.data(), Data, argsize);
-  auto argname = fmt::string_view(argnamebuffer.data(), argsize);
+  auto argname = argnamebuffer.data();
 #else
-  auto argname = fmt::string_view(fmt_fuzzer::as_chars(Data), argsize);
+  auto argname = fmt_fuzzer::as_chars(Data);
 #endif
   Data += argsize;
   Size -= argsize;
@@ -105,7 +105,7 @@ template <typename Callback> void invoke(int index, Callback callback) {
   }
 }
 
-extern "C" int LLVMFuzzerTestOneInput(const uint8_t* Data, std::size_t Size) {
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t* Data, size_t Size) {
   if (Size <= 3) {
     return 0;
   }

test/fuzzing/one_arg.cpp

@@ -13,7 +13,7 @@
 using fmt_fuzzer::Nfixed;
 
 template <typename Item>
-void invoke_fmt(const uint8_t* Data, std::size_t Size) {
+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) {
@@ -40,7 +40,7 @@ void invoke_fmt(const uint8_t* Data, std::size_t Size) {
 #endif
 }
 
-void invoke_fmt_time(const uint8_t* Data, std::size_t Size) {
+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");
@@ -69,7 +69,7 @@ void invoke_fmt_time(const uint8_t* Data, std::size_t Size) {
   }
 }
 
-extern "C" int LLVMFuzzerTestOneInput(const uint8_t* Data, std::size_t Size) {
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t* Data, size_t Size) {
   if (Size <= 3) {
     return 0;
   }

test/fuzzing/sprintf.cpp

@@ -10,7 +10,7 @@
 using fmt_fuzzer::Nfixed;
 
 template <typename Item1, typename Item2>
-void invoke_fmt(const uint8_t* Data, std::size_t Size) {
+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");
@@ -90,7 +90,7 @@ template <typename Callback> void invoke(int index, Callback callback) {
   }
 }
 
-extern "C" int LLVMFuzzerTestOneInput(const uint8_t* Data, std::size_t Size) {
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t* Data, size_t Size) {
   if (Size <= 3) {
     return 0;
   }

test/fuzzing/two_args.cpp

@@ -10,7 +10,7 @@
 constexpr auto Nfixed = fmt_fuzzer::Nfixed;
 
 template <typename Item1, typename Item2>
-void invoke_fmt(const uint8_t* Data, std::size_t Size) {
+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");
@@ -86,7 +86,7 @@ template <typename Callback> void invoke(int index, Callback callback) {
   }
 }
 
-extern "C" int LLVMFuzzerTestOneInput(const uint8_t* Data, std::size_t Size) {
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t* Data, size_t Size) {
   if (Size <= 3) {
     return 0;
   }

test/gmock-gtest-all.cc

@@ -344,6 +344,7 @@ class GTEST_API_ SingleFailureChecker {
 #  include <sys/mman.h>  // NOLINT
 #  include <sys/time.h>  // NOLINT
 #  include <unistd.h>    // NOLINT
+
 #  include <string>
 
 #elif GTEST_OS_SYMBIAN
@@ -7728,6 +7729,7 @@ InternalRunDeathTestFlag* ParseInternalRunDeathTestFlag() {
 #  include <sys/syslimits.h>
 #else
 #  include <limits.h>
+
 #  include <climits>  // Some Linux distributions define PATH_MAX here.
 #endif                // GTEST_OS_WINDOWS_MOBILE
 
@@ -8899,6 +8901,7 @@ const char* StringFromGTestEnv(const char* flag, const char* default_value) {
 
 #include <ctype.h>
 #include <stdio.h>
+
 #include <ostream>  // NOLINT
 #include <string>
 
@@ -9494,6 +9497,7 @@ const char* TypedTestCasePState::VerifyRegisteredTestNames(
 // This file implements cardinalities.
 
 #include <limits.h>
+
 #include <ostream>  // NOLINT
 #include <sstream>
 #include <string>
@@ -9646,6 +9650,7 @@ GTEST_API_ Cardinality Exactly(int n) { return Between(n, n); }
 // USE THEM IN USER CODE.
 
 #include <ctype.h>
+
 #include <ostream>  // NOLINT
 #include <string>
 
@@ -9808,6 +9813,7 @@ GTEST_API_ void Log(LogSeverity severity, const string& message,
 // utilities for defining matchers.
 
 #include <string.h>
+
 #include <sstream>
 #include <string>
 
@@ -10291,6 +10297,7 @@ bool UnorderedElementsAreMatcherImplBase::
 // EXPECT_CALL).
 
 #include <stdlib.h>
+
 #include <iostream>  // NOLINT
 #include <map>
 #include <set>

test/grisu-test.cc

@@ -48,10 +48,28 @@ TEST(GrisuTest, Prettify) {
   EXPECT_EQ("1e-05", fmt::format("{}", 1e-5));
   EXPECT_EQ("9.999e-05", fmt::format("{}", 9.999e-5));
   EXPECT_EQ("10000000000.0", fmt::format("{}", 1e10));
-  EXPECT_EQ("1e+11", fmt::format("{}", 1e11));
+  EXPECT_EQ("100000000000.0", fmt::format("{}", 1e11));
   EXPECT_EQ("12340000000.0", fmt::format("{}", 1234e7));
   EXPECT_EQ("12.34", fmt::format("{}", 1234e-2));
   EXPECT_EQ("0.001234", fmt::format("{}", 1234e-6));
+  EXPECT_EQ("0.1", fmt::format("{}", 0.1f));
+  EXPECT_EQ("0.10000000149011612", fmt::format("{}", double(0.1f)));
 }
 
 TEST(GrisuTest, ZeroPrecision) { EXPECT_EQ("1", fmt::format("{:.0}", 1.0)); }
+
+TEST(GrisuTest, Fallback) {
+  EXPECT_EQ("1e+23", fmt::format("{}", 1e23));
+  EXPECT_EQ("9e-265", fmt::format("{}", 9e-265));
+  EXPECT_EQ("5.423717798060526e+125",
+            fmt::format("{}", 5.423717798060526e+125));
+  EXPECT_EQ("1.372371880954233e-288",
+            fmt::format("{}", 1.372371880954233e-288));
+  EXPECT_EQ("55388492.622190244", fmt::format("{}", 55388492.622190244));
+  EXPECT_EQ("2.2506787569811123e-253",
+            fmt::format("{}", 2.2506787569811123e-253));
+  EXPECT_EQ("1103618912042992.8", fmt::format("{}", 1103618912042992.8));
+  // pow(2, -25) - assymetric boundaries:
+  EXPECT_EQ("2.9802322387695312e-08",
+            fmt::format("{}", 2.9802322387695312e-08));
+}

test/gtest-extra-test.cc

@@ -8,6 +8,7 @@
 #include "gtest-extra.h"
 
 #include <gtest/gtest-spi.h>
+
 #include <algorithm>
 #include <cstring>
 #include <memory>
@@ -74,14 +75,6 @@ TEST_F(SingleEvaluationTest, FailedEXPECT_SYSTEM_ERROR) {
   EXPECT_EQ(s_ + 1, p_);
 }
 
-// Tests that when EXPECT_WRITE fails, it evaluates its message argument
-// exactly once.
-TEST_F(SingleEvaluationTest, FailedEXPECT_WRITE) {
-  EXPECT_NONFATAL_FAILURE(EXPECT_WRITE(stdout, std::printf("test"), p_++),
-                          "01234");
-  EXPECT_EQ(s_ + 1, p_);
-}
-
 // Tests that assertion arguments are evaluated exactly once.
 TEST_F(SingleEvaluationTest, ExceptionTests) {
   // successful EXPECT_THROW_MSG
@@ -163,30 +156,59 @@ TEST_F(SingleEvaluationTest, SystemErrorTests) {
   EXPECT_EQ(4, b_);
 }
 
+#if FMT_USE_FCNTL
+// Tests that when EXPECT_WRITE fails, it evaluates its message argument
+// exactly once.
+TEST_F(SingleEvaluationTest, FailedEXPECT_WRITE) {
+  EXPECT_NONFATAL_FAILURE(EXPECT_WRITE(stdout, std::printf("test"), p_++),
+                          "01234");
+  EXPECT_EQ(s_ + 1, p_);
+}
+
 // Tests that assertion arguments are evaluated exactly once.
 TEST_F(SingleEvaluationTest, WriteTests) {
   // successful EXPECT_WRITE
-  EXPECT_WRITE(stdout,
-               {  // NOLINT
-                 a_++;
-                 std::printf("test");
-               },
-               (b_++, "test"));
+  EXPECT_WRITE(
+      stdout,
+      {  // NOLINT
+        a_++;
+        std::printf("test");
+      },
+      (b_++, "test"));
   EXPECT_EQ(1, a_);
   EXPECT_EQ(1, b_);
 
   // failed EXPECT_WRITE
-  EXPECT_NONFATAL_FAILURE(EXPECT_WRITE(stdout,
-                                       {  // NOLINT
-                                         a_++;
-                                         std::printf("test");
-                                       },
-                                       (b_++, "other")),
+  EXPECT_NONFATAL_FAILURE(EXPECT_WRITE(
+                              stdout,
+                              {  // NOLINT
+                                a_++;
+                                std::printf("test");
+                              },
+                              (b_++, "other")),
                           "Actual: test");
   EXPECT_EQ(2, a_);
   EXPECT_EQ(2, b_);
 }
 
+// Tests EXPECT_WRITE.
+TEST(ExpectTest, EXPECT_WRITE) {
+  EXPECT_WRITE(stdout, do_nothing(), "");
+  EXPECT_WRITE(stdout, std::printf("test"), "test");
+  EXPECT_WRITE(stderr, std::fprintf(stderr, "test"), "test");
+  EXPECT_NONFATAL_FAILURE(EXPECT_WRITE(stdout, std::printf("that"), "this"),
+                          "Expected: this\n"
+                          "  Actual: that");
+}
+
+TEST(StreamingAssertionsTest, EXPECT_WRITE) {
+  EXPECT_WRITE(stdout, std::printf("test"), "test") << "unexpected failure";
+  EXPECT_NONFATAL_FAILURE(EXPECT_WRITE(stdout, std::printf("test"), "other")
+                              << "expected failure",
+                          "expected failure");
+}
+#endif  // FMT_USE_FCNTL
+
 // Tests that the compiler will not complain about unreachable code in the
 // EXPECT_THROW_MSG macro.
 TEST(ExpectThrowTest, DoesNotGenerateUnreachableCodeWarning) {
@@ -280,16 +302,6 @@ TEST(ExpectTest, EXPECT_SYSTEM_ERROR) {
           format_system_error(EDOM, "test")));
 }
 
-// Tests EXPECT_WRITE.
-TEST(ExpectTest, EXPECT_WRITE) {
-  EXPECT_WRITE(stdout, do_nothing(), "");
-  EXPECT_WRITE(stdout, std::printf("test"), "test");
-  EXPECT_WRITE(stderr, std::fprintf(stderr, "test"), "test");
-  EXPECT_NONFATAL_FAILURE(EXPECT_WRITE(stdout, std::printf("that"), "this"),
-                          "Expected: this\n"
-                          "  Actual: that");
-}
-
 TEST(StreamingAssertionsTest, EXPECT_THROW_MSG) {
   EXPECT_THROW_MSG(throw_exception(), std::exception, "test")
       << "unexpected failure";
@@ -308,20 +320,13 @@ TEST(StreamingAssertionsTest, EXPECT_SYSTEM_ERROR) {
       "expected failure");
 }
 
-TEST(StreamingAssertionsTest, EXPECT_WRITE) {
-  EXPECT_WRITE(stdout, std::printf("test"), "test") << "unexpected failure";
-  EXPECT_NONFATAL_FAILURE(EXPECT_WRITE(stdout, std::printf("test"), "other")
-                              << "expected failure",
-                          "expected failure");
-}
-
 TEST(UtilTest, FormatSystemError) {
   fmt::memory_buffer out;
   fmt::format_system_error(out, EDOM, "test message");
   EXPECT_EQ(to_string(out), format_system_error(EDOM, "test message"));
 }
 
-#if FMT_USE_FILE_DESCRIPTORS
+#if FMT_USE_FCNTL
 
 using fmt::buffered_file;
 using fmt::error_code;
@@ -415,16 +420,17 @@ TEST(OutputRedirectTest, ErrorInDtor) {
   std::unique_ptr<OutputRedirect> redir(new OutputRedirect(f.get()));
   // Put a character in a file buffer.
   EXPECT_EQ('x', fputc('x', f.get()));
-  EXPECT_WRITE(stderr,
-               {
-                 // The close function must be called inside EXPECT_WRITE,
-                 // otherwise the system may recycle closed file descriptor when
-                 // redirecting the output in EXPECT_STDERR and the second close
-                 // will break output redirection.
-                 FMT_POSIX(close(write_fd));
-                 SUPPRESS_ASSERT(redir.reset(nullptr));
-               },
-               format_system_error(EBADF, "cannot flush stream"));
+  EXPECT_WRITE(
+      stderr,
+      {
+        // The close function must be called inside EXPECT_WRITE,
+        // otherwise the system may recycle closed file descriptor when
+        // redirecting the output in EXPECT_STDERR and the second close
+        // will break output redirection.
+        FMT_POSIX(close(write_fd));
+        SUPPRESS_ASSERT(redir.reset(nullptr));
+      },
+      format_system_error(EBADF, "cannot flush stream"));
   write_copy.dup2(write_fd);  // "undo" close or dtor of buffered_file will fail
 }
 

test/gtest-extra.cc

@@ -7,7 +7,7 @@
 
 #include "gtest-extra.h"
 
-#if FMT_USE_FILE_DESCRIPTORS
+#if FMT_USE_FCNTL
 
 using fmt::file;
 
@@ -57,7 +57,7 @@ std::string OutputRedirect::restore_and_read() {
   if (read_end_.descriptor() == -1) return content;  // Already read.
   enum { BUFFER_SIZE = 4096 };
   char buffer[BUFFER_SIZE];
-  std::size_t count = 0;
+  size_t count = 0;
   do {
     count = read_end_.read(buffer, BUFFER_SIZE);
     content.append(buffer, count);
@@ -66,9 +66,9 @@ std::string OutputRedirect::restore_and_read() {
   return content;
 }
 
-std::string read(file& f, std::size_t count) {
+std::string read(file& f, size_t count) {
   std::string buffer(count, '\0');
-  std::size_t n = 0, offset = 0;
+  size_t n = 0, offset = 0;
   do {
     n = f.read(&buffer[offset], count - offset);
     // We can't read more than size_t bytes since count has type size_t.
@@ -78,7 +78,7 @@ std::string read(file& f, std::size_t count) {
   return buffer;
 }
 
-#endif  // FMT_USE_FILE_DESCRIPTORS
+#endif  // FMT_USE_FCNTL
 
 std::string format_system_error(int error_code, fmt::string_view message) {
   fmt::memory_buffer out;

test/gtest-extra.h

@@ -9,18 +9,10 @@
 #define FMT_GTEST_EXTRA_H_
 
 #include <string>
+
+#include "fmt/os.h"
 #include "gmock.h"
 
-#include "fmt/core.h"
-
-#ifndef FMT_USE_FILE_DESCRIPTORS
-#  define FMT_USE_FILE_DESCRIPTORS 0
-#endif
-
-#if FMT_USE_FILE_DESCRIPTORS
-#  include "fmt/posix.h"
-#endif
-
 #define FMT_TEST_THROW_(statement, expected_exception, expected_message, fail) \
   GTEST_AMBIGUOUS_ELSE_BLOCKER_                                                \
   if (::testing::AssertionResult gtest_ar = ::testing::AssertionSuccess()) {   \
@@ -65,7 +57,7 @@ std::string format_system_error(int error_code, fmt::string_view message);
   EXPECT_THROW_MSG(statement, fmt::system_error,            \
                    format_system_error(error_code, message))
 
-#if FMT_USE_FILE_DESCRIPTORS
+#if FMT_USE_FCNTL
 
 // Captures file output by redirecting it to a pipe.
 // The output it can handle is limited by the pipe capacity.
@@ -146,12 +138,15 @@ class SuppressAssert {
     EXPECT_SYSTEM_ERROR(SUPPRESS_ASSERT(statement), error_code, message)
 
 // Attempts to read count characters from a file.
-std::string read(fmt::file& f, std::size_t count);
+std::string read(fmt::file& f, size_t count);
 
 #  define EXPECT_READ(file, expected_content) \
-    EXPECT_EQ(expected_content, read(file, std::strlen(expected_content)))
+    EXPECT_EQ(expected_content, \
+              read(file, fmt::string_view(expected_content).size()))
 
-#endif  // FMT_USE_FILE_DESCRIPTORS
+#else
+#  define EXPECT_WRITE(file, statement, expected_output) SUCCEED()
+#endif  // FMT_USE_FCNTL
 
 template <typename Mock> struct ScopedMock : testing::StrictMock<Mock> {
   ScopedMock() { Mock::instance = this; }

test/locale-test.cc

@@ -6,47 +6,86 @@
 // For the license information refer to format.h.
 
 #include "fmt/locale.h"
+
 #include "gmock.h"
 
+using fmt::detail::max_value;
+
 #ifndef FMT_STATIC_THOUSANDS_SEPARATOR
 template <typename Char> struct numpunct : std::numpunct<Char> {
  protected:
   Char do_decimal_point() const FMT_OVERRIDE { return '?'; }
+  std::string do_grouping() const FMT_OVERRIDE { return "\03"; }
   Char do_thousands_sep() const FMT_OVERRIDE { return '~'; }
 };
 
+template <typename Char> struct no_grouping : std::numpunct<Char> {
+ protected:
+  Char do_decimal_point() const FMT_OVERRIDE { return '.'; }
+  std::string do_grouping() const FMT_OVERRIDE { return ""; }
+  Char do_thousands_sep() const FMT_OVERRIDE { return ','; }
+};
+
+template <typename Char> struct special_grouping : std::numpunct<Char> {
+ protected:
+  Char do_decimal_point() const FMT_OVERRIDE { return '.'; }
+  std::string do_grouping() const FMT_OVERRIDE { return "\03\02"; }
+  Char do_thousands_sep() const FMT_OVERRIDE { return ','; }
+};
+
+template <typename Char> struct small_grouping : std::numpunct<Char> {
+ protected:
+  Char do_decimal_point() const FMT_OVERRIDE { return '.'; }
+  std::string do_grouping() const FMT_OVERRIDE { return "\01"; }
+  Char do_thousands_sep() const FMT_OVERRIDE { return ','; }
+};
+
 TEST(LocaleTest, DoubleDecimalPoint) {
   std::locale loc(std::locale(), new numpunct<char>());
-  EXPECT_EQ("1?23", fmt::format(loc, "{:n}", 1.23));
-  // Test with Grisu disabled.
-  fmt::memory_buffer buf;
-  fmt::internal::writer w(buf, fmt::internal::locale_ref(loc));
-  auto specs = fmt::format_specs();
-  specs.type = 'n';
-  w.write_double<double, false>(1.23, specs);
-  EXPECT_EQ(fmt::to_string(buf), "1?23");
+  EXPECT_EQ("1?23", fmt::format(loc, "{:L}", 1.23));
 }
 
 TEST(LocaleTest, Format) {
   std::locale loc(std::locale(), new numpunct<char>());
-  EXPECT_EQ("1,234,567", fmt::format(std::locale(), "{:n}", 1234567));
-  EXPECT_EQ("1~234~567", fmt::format(loc, "{:n}", 1234567));
+  EXPECT_EQ("1234567", fmt::format(std::locale(), "{:L}", 1234567));
+  EXPECT_EQ("1~234~567", fmt::format(loc, "{:L}", 1234567));
+  EXPECT_EQ("-1~234~567", fmt::format(loc, "{:L}", -1234567));
   fmt::format_arg_store<fmt::format_context, int> as{1234567};
-  EXPECT_EQ("1~234~567", fmt::vformat(loc, "{:n}", fmt::format_args(as)));
+  EXPECT_EQ("1~234~567", fmt::vformat(loc, "{:L}", fmt::format_args(as)));
   std::string s;
-  fmt::format_to(std::back_inserter(s), loc, "{:n}", 1234567);
+  fmt::format_to(std::back_inserter(s), loc, "{:L}", 1234567);
   EXPECT_EQ("1~234~567", s);
+
+  std::locale no_grouping_loc(std::locale(), new no_grouping<char>());
+  EXPECT_EQ("1234567", fmt::format(no_grouping_loc, "{:L}", 1234567));
+
+  std::locale special_grouping_loc(std::locale(), new special_grouping<char>());
+  EXPECT_EQ("1,23,45,678", fmt::format(special_grouping_loc, "{:L}", 12345678));
+
+  std::locale small_grouping_loc(std::locale(), new small_grouping<char>());
+  EXPECT_EQ("4,2,9,4,9,6,7,2,9,5",
+            fmt::format(small_grouping_loc, "{:L}", max_value<uint32_t>()));
 }
 
 TEST(LocaleTest, WFormat) {
   std::locale loc(std::locale(), new numpunct<wchar_t>());
-  EXPECT_EQ(L"1,234,567", fmt::format(std::locale(), L"{:n}", 1234567));
-  EXPECT_EQ(L"1~234~567", fmt::format(loc, L"{:n}", 1234567));
+  EXPECT_EQ(L"1234567", fmt::format(std::locale(), L"{:L}", 1234567));
+  EXPECT_EQ(L"1~234~567", fmt::format(loc, L"{:L}", 1234567));
   fmt::format_arg_store<fmt::wformat_context, int> as{1234567};
-  EXPECT_EQ(L"1~234~567", fmt::vformat(loc, L"{:n}", fmt::wformat_args(as)));
-  auto sep =
-      std::use_facet<std::numpunct<wchar_t>>(std::locale("C")).thousands_sep();
-  auto result = sep == ',' ? L"1,234,567" : L"1234567";
-  EXPECT_EQ(result, fmt::format(std::locale("C"), L"{:n}", 1234567));
+  EXPECT_EQ(L"1~234~567", fmt::vformat(loc, L"{:L}", fmt::wformat_args(as)));
+  EXPECT_EQ(L"1234567", fmt::format(std::locale("C"), L"{:L}", 1234567));
+
+  std::locale no_grouping_loc(std::locale(), new no_grouping<wchar_t>());
+  EXPECT_EQ(L"1234567", fmt::format(no_grouping_loc, L"{:L}", 1234567));
+
+  std::locale special_grouping_loc(std::locale(),
+                                   new special_grouping<wchar_t>());
+  EXPECT_EQ(L"1,23,45,678",
+            fmt::format(special_grouping_loc, L"{:L}", 12345678));
+
+  std::locale small_grouping_loc(std::locale(), new small_grouping<wchar_t>());
+  EXPECT_EQ(L"4,2,9,4,9,6,7,2,9,5",
+            fmt::format(small_grouping_loc, L"{:L}", max_value<uint32_t>()));
 }
+
 #endif  // FMT_STATIC_THOUSANDS_SEPARATOR

test/mock-allocator.h

@@ -16,8 +16,8 @@ template <typename T> class mock_allocator {
   mock_allocator() {}
   mock_allocator(const mock_allocator&) {}
   typedef T value_type;
-  MOCK_METHOD1_T(allocate, T*(std::size_t n));
-  MOCK_METHOD2_T(deallocate, void(T* p, std::size_t n));
+  MOCK_METHOD1_T(allocate, T*(size_t n));
+  MOCK_METHOD2_T(deallocate, void(T* p, size_t n));
 };
 
 template <typename Allocator> class allocator_ref {
@@ -51,10 +51,10 @@ template <typename Allocator> class allocator_ref {
  public:
   Allocator* get() const { return alloc_; }
 
-  value_type* allocate(std::size_t n) {
+  value_type* allocate(size_t n) {
     return std::allocator_traits<Allocator>::allocate(*alloc_, n);
   }
-  void deallocate(value_type* p, std::size_t n) { alloc_->deallocate(p, n); }
+  void deallocate(value_type* p, size_t n) { alloc_->deallocate(p, n); }
 };
 
 #endif  // FMT_MOCK_ALLOCATOR_H_

test/os-test.cc

@@ -1,15 +1,16 @@
-// Formatting library for C++ - tests of the C++ interface to POSIX functions
+// Formatting library for C++ - tests of the OS-specific functionality
 //
 // Copyright (c) 2012 - present, Victor Zverovich
 // All rights reserved.
 //
 // For the license information refer to format.h.
 
+#include "fmt/os.h"
+
 #include <cstdlib>  // std::exit
 #include <cstring>
 #include <memory>
 
-#include "fmt/posix.h"
 #include "gtest-extra.h"
 #include "util.h"
 
@@ -19,6 +20,124 @@
 
 using fmt::buffered_file;
 using fmt::error_code;
+
+#ifdef _WIN32
+
+#  include <windows.h>
+
+TEST(UtilTest, UTF16ToUTF8) {
+  std::string s = "ёжик";
+  fmt::detail::utf16_to_utf8 u(L"\x0451\x0436\x0438\x043A");
+  EXPECT_EQ(s, u.str());
+  EXPECT_EQ(s.size(), u.size());
+}
+
+TEST(UtilTest, UTF16ToUTF8EmptyString) {
+  std::string s = "";
+  fmt::detail::utf16_to_utf8 u(L"");
+  EXPECT_EQ(s, u.str());
+  EXPECT_EQ(s.size(), u.size());
+}
+
+template <typename Converter, typename Char>
+void check_utf_conversion_error(
+    const char* message,
+    fmt::basic_string_view<Char> str = fmt::basic_string_view<Char>(0, 1)) {
+  fmt::memory_buffer out;
+  fmt::detail::format_windows_error(out, ERROR_INVALID_PARAMETER, message);
+  fmt::system_error error(0, "");
+  try {
+    (Converter)(str);
+  } catch (const fmt::system_error& e) {
+    error = e;
+  }
+  EXPECT_EQ(ERROR_INVALID_PARAMETER, error.error_code());
+  EXPECT_EQ(fmt::to_string(out), error.what());
+}
+
+TEST(UtilTest, UTF16ToUTF8Error) {
+  check_utf_conversion_error<fmt::detail::utf16_to_utf8, wchar_t>(
+      "cannot convert string from UTF-16 to UTF-8");
+}
+
+TEST(UtilTest, UTF16ToUTF8Convert) {
+  fmt::detail::utf16_to_utf8 u;
+  EXPECT_EQ(ERROR_INVALID_PARAMETER, u.convert(fmt::wstring_view(0, 1)));
+  EXPECT_EQ(ERROR_INVALID_PARAMETER,
+            u.convert(fmt::wstring_view(L"foo", INT_MAX + 1u)));
+}
+
+TEST(UtilTest, FormatWindowsError) {
+  LPWSTR message = 0;
+  FormatMessageW(FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM |
+                     FORMAT_MESSAGE_IGNORE_INSERTS,
+                 0, ERROR_FILE_EXISTS,
+                 MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
+                 reinterpret_cast<LPWSTR>(&message), 0, 0);
+  fmt::detail::utf16_to_utf8 utf8_message(message);
+  LocalFree(message);
+  fmt::memory_buffer actual_message;
+  fmt::detail::format_windows_error(actual_message, ERROR_FILE_EXISTS, "test");
+  EXPECT_EQ(fmt::format("test: {}", utf8_message.str()),
+            fmt::to_string(actual_message));
+  actual_message.resize(0);
+  auto max_size = fmt::detail::max_value<size_t>();
+  fmt::detail::format_windows_error(actual_message, ERROR_FILE_EXISTS,
+                                    fmt::string_view(0, max_size));
+  EXPECT_EQ(fmt::format("error {}", ERROR_FILE_EXISTS),
+            fmt::to_string(actual_message));
+}
+
+TEST(UtilTest, FormatLongWindowsError) {
+  LPWSTR message = 0;
+  // this error code is not available on all Windows platforms and
+  // Windows SDKs, so do not fail the test if the error string cannot
+  // be retrieved.
+  const int provisioning_not_allowed =
+      0x80284013L /*TBS_E_PROVISIONING_NOT_ALLOWED*/;
+  if (FormatMessageW(FORMAT_MESSAGE_ALLOCATE_BUFFER |
+                         FORMAT_MESSAGE_FROM_SYSTEM |
+                         FORMAT_MESSAGE_IGNORE_INSERTS,
+                     0, static_cast<DWORD>(provisioning_not_allowed),
+                     MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
+                     reinterpret_cast<LPWSTR>(&message), 0, 0) == 0) {
+    return;
+  }
+  fmt::detail::utf16_to_utf8 utf8_message(message);
+  LocalFree(message);
+  fmt::memory_buffer actual_message;
+  fmt::detail::format_windows_error(actual_message, provisioning_not_allowed,
+                                    "test");
+  EXPECT_EQ(fmt::format("test: {}", utf8_message.str()),
+            fmt::to_string(actual_message));
+}
+
+TEST(UtilTest, WindowsError) {
+  fmt::system_error error(0, "");
+  try {
+    throw fmt::windows_error(ERROR_FILE_EXISTS, "test {}", "error");
+  } catch (const fmt::system_error& e) {
+    error = e;
+  }
+  fmt::memory_buffer message;
+  fmt::detail::format_windows_error(message, ERROR_FILE_EXISTS, "test error");
+  EXPECT_EQ(to_string(message), error.what());
+  EXPECT_EQ(ERROR_FILE_EXISTS, error.error_code());
+}
+
+TEST(UtilTest, ReportWindowsError) {
+  fmt::memory_buffer out;
+  fmt::detail::format_windows_error(out, ERROR_FILE_EXISTS, "test error");
+  out.push_back('\n');
+  EXPECT_WRITE(stderr,
+               fmt::report_windows_error(ERROR_FILE_EXISTS, "test error"),
+               fmt::to_string(out));
+}
+
+#endif  // _WIN32
+
+#if FMT_USE_FCNTL
+
 using fmt::file;
 
 // Checks if the file is open by reading one character from it.
@@ -45,10 +164,10 @@ static file open_file() {
 
 // Attempts to write a string to a file.
 static void write(file& f, fmt::string_view s) {
-  std::size_t num_chars_left = s.size();
+  size_t num_chars_left = s.size();
   const char* ptr = s.data();
   do {
-    std::size_t count = f.write(ptr, num_chars_left);
+    size_t count = f.write(ptr, num_chars_left);
     ptr += count;
     // We can't write more than size_t bytes since num_chars_left
     // has type size_t.
@@ -119,16 +238,17 @@ TEST(BufferedFileTest, CloseFileInDtor) {
 
 TEST(BufferedFileTest, CloseErrorInDtor) {
   std::unique_ptr<buffered_file> f(new buffered_file(open_buffered_file()));
-  EXPECT_WRITE(stderr,
-               {
-                 // The close function must be called inside EXPECT_WRITE,
-                 // otherwise the system may recycle closed file descriptor when
-                 // redirecting the output in EXPECT_STDERR and the second close
-                 // will break output redirection.
-                 FMT_POSIX(close(f->fileno()));
-                 SUPPRESS_ASSERT(f.reset(nullptr));
-               },
-               format_system_error(EBADF, "cannot close file") + "\n");
+  EXPECT_WRITE(
+      stderr,
+      {
+        // The close function must be called inside EXPECT_WRITE,
+        // otherwise the system may recycle closed file descriptor when
+        // redirecting the output in EXPECT_STDERR and the second close
+        // will break output redirection.
+        FMT_POSIX(close(f->fileno()));
+        SUPPRESS_ASSERT(f.reset(nullptr));
+      },
+      format_system_error(EBADF, "cannot close file") + "\n");
 }
 
 TEST(BufferedFileTest, Close) {
@@ -148,7 +268,7 @@ TEST(BufferedFileTest, CloseError) {
 
 TEST(BufferedFileTest, Fileno) {
   buffered_file f;
-#ifndef __COVERITY__
+#  ifndef __COVERITY__
   // fileno on a null FILE pointer either crashes or returns an error.
   // Disable Coverity because this is intentional.
   EXPECT_DEATH_IF_SUPPORTED(
@@ -160,13 +280,33 @@ TEST(BufferedFileTest, Fileno) {
         }
       },
       "");
-#endif
+#  endif
   f = open_buffered_file();
   EXPECT_TRUE(f.fileno() != -1);
   file copy = file::dup(f.fileno());
   EXPECT_READ(copy, FILE_CONTENT);
 }
 
+TEST(DirectBufferedFileTest, Print) {
+  fmt::direct_buffered_file out(
+    "test-file", fmt::file::WRONLY | fmt::file::CREATE);
+  fmt::print(out, "The answer is {}.\n", 42);
+  out.close();
+  file in("test-file", file::RDONLY);
+  EXPECT_READ(in, "The answer is 42.\n");
+}
+
+TEST(DirectBufferedFileTest, BufferBoundary) {
+  auto str = std::string(4096, 'x');
+  fmt::direct_buffered_file out(
+    "test-file", fmt::file::WRONLY | fmt::file::CREATE);
+  fmt::print(out, "{}", str);
+  fmt::print(out, "{}", str);
+  out.close();
+  file in("test-file", file::RDONLY);
+  EXPECT_READ(in, str + str);
+}
+
 TEST(FileTest, DefaultCtor) {
   file f;
   EXPECT_EQ(-1, f.descriptor());
@@ -250,16 +390,17 @@ TEST(FileTest, CloseFileInDtor) {
 
 TEST(FileTest, CloseErrorInDtor) {
   std::unique_ptr<file> f(new file(open_file()));
-  EXPECT_WRITE(stderr,
-               {
-                 // The close function must be called inside EXPECT_WRITE,
-                 // otherwise the system may recycle closed file descriptor when
-                 // redirecting the output in EXPECT_STDERR and the second close
-                 // will break output redirection.
-                 FMT_POSIX(close(f->descriptor()));
-                 SUPPRESS_ASSERT(f.reset(nullptr));
-               },
-               format_system_error(EBADF, "cannot close file") + "\n");
+  EXPECT_WRITE(
+      stderr,
+      {
+        // The close function must be called inside EXPECT_WRITE,
+        // otherwise the system may recycle closed file descriptor when
+        // redirecting the output in EXPECT_STDERR and the second close
+        // will break output redirection.
+        FMT_POSIX(close(f->descriptor()));
+        SUPPRESS_ASSERT(f.reset(nullptr));
+      },
+      format_system_error(EBADF, "cannot close file") + "\n");
 }
 
 TEST(FileTest, Close) {
@@ -312,13 +453,13 @@ TEST(FileTest, Dup) {
   EXPECT_EQ(FILE_CONTENT, read(copy, std::strlen(FILE_CONTENT)));
 }
 
-#ifndef __COVERITY__
+#  ifndef __COVERITY__
 TEST(FileTest, DupError) {
   int value = -1;
   EXPECT_SYSTEM_ERROR_NOASSERT(file::dup(value), EBADF,
                                "cannot duplicate file descriptor -1");
 }
-#endif
+#  endif
 
 TEST(FileTest, Dup2) {
   file f = open_file();
@@ -368,11 +509,12 @@ TEST(FileTest, Fdopen) {
   EXPECT_EQ(read_fd, FMT_POSIX(fileno(read_end.fdopen("r").get())));
 }
 
-#ifdef FMT_LOCALE
+#  ifdef FMT_LOCALE
 TEST(LocaleTest, Strtod) {
-  fmt::Locale locale;
+  fmt::locale loc;
   const char *start = "4.2", *ptr = start;
-  EXPECT_EQ(4.2, locale.strtod(ptr));
+  EXPECT_EQ(4.2, loc.strtod(ptr));
   EXPECT_EQ(start + 3, ptr);
 }
-#endif
+#  endif
+#endif  // FMT_USE_FCNTL

test/ostream-test.cc

@@ -21,9 +21,9 @@ template <> struct formatter<test> : formatter<int> {
 };
 }  // namespace fmt
 
-#include "fmt/ostream.h"
-
 #include <sstream>
+
+#include "fmt/ostream.h"
 #include "gmock.h"
 #include "gtest-extra.h"
 #include "util.h"
@@ -64,22 +64,23 @@ TEST(OStreamTest, Enum) {
   EXPECT_EQ(L"0", fmt::format(L"{}", unstreamable_enum()));
 }
 
-using range = fmt::buffer_range<char>;
-
-struct test_arg_formatter : fmt::arg_formatter<range> {
+struct test_arg_formatter
+    : fmt::detail::arg_formatter<fmt::format_context::iterator, char> {
   fmt::format_parse_context parse_ctx;
   test_arg_formatter(fmt::format_context& ctx, fmt::format_specs& s)
-      : fmt::arg_formatter<range>(ctx, &parse_ctx, &s), parse_ctx("") {}
+      : fmt::detail::arg_formatter<fmt::format_context::iterator, char>(
+            ctx, &parse_ctx, &s),
+        parse_ctx("") {}
 };
 
 TEST(OStreamTest, CustomArg) {
   fmt::memory_buffer buffer;
-  fmt::internal::buffer<char>& base = buffer;
+  fmt::detail::buffer<char>& base = buffer;
   fmt::format_context ctx(std::back_inserter(base), fmt::format_args());
   fmt::format_specs spec;
   test_arg_formatter af(ctx, spec);
   fmt::visit_format_arg(
-      af, fmt::internal::make_arg<fmt::format_context>(streamable_enum()));
+      af, fmt::detail::make_arg<fmt::format_context>(streamable_enum()));
   EXPECT_EQ("streamable_enum", std::string(buffer.data(), buffer.size()));
 }
 
@@ -95,7 +96,7 @@ TEST(OStreamTest, Format) {
 TEST(OStreamTest, FormatSpecs) {
   EXPECT_EQ("def  ", format("{0:<5}", TestString("def")));
   EXPECT_EQ("  def", format("{0:>5}", TestString("def")));
-#if FMT_NUMERIC_ALIGN
+#if FMT_DEPRECATED_NUMERIC_ALIGN
   EXPECT_THROW_MSG(format("{0:=5}", TestString("def")), format_error,
                    "format specifier requires numeric argument");
 #endif
@@ -140,18 +141,18 @@ TEST(OStreamTest, WriteToOStream) {
   fmt::memory_buffer buffer;
   const char* foo = "foo";
   buffer.append(foo, foo + std::strlen(foo));
-  fmt::internal::write(os, buffer);
+  fmt::detail::write_buffer(os, buffer);
   EXPECT_EQ("foo", os.str());
 }
 
 TEST(OStreamTest, WriteToOStreamMaxSize) {
-  std::size_t max_size = fmt::internal::max_value<std::size_t>();
-  std::streamsize max_streamsize = fmt::internal::max_value<std::streamsize>();
-  if (max_size <= fmt::internal::to_unsigned(max_streamsize)) return;
+  size_t max_size = fmt::detail::max_value<size_t>();
+  std::streamsize max_streamsize = fmt::detail::max_value<std::streamsize>();
+  if (max_size <= fmt::detail::to_unsigned(max_streamsize)) return;
 
-  struct test_buffer : fmt::internal::buffer<char> {
-    explicit test_buffer(std::size_t size) { resize(size); }
-    void grow(std::size_t) {}
+  struct test_buffer : fmt::detail::buffer<char> {
+    explicit test_buffer(size_t size) { resize(size); }
+    void grow(size_t) {}
   } buffer(max_size);
 
   struct mock_streambuf : std::streambuf {
@@ -171,13 +172,13 @@ TEST(OStreamTest, WriteToOStreamMaxSize) {
   typedef std::make_unsigned<std::streamsize>::type ustreamsize;
   ustreamsize size = max_size;
   do {
-    auto n = std::min(size, fmt::internal::to_unsigned(max_streamsize));
+    auto n = std::min(size, fmt::detail::to_unsigned(max_streamsize));
     EXPECT_CALL(streambuf, xsputn(data, static_cast<std::streamsize>(n)))
         .WillOnce(testing::Return(max_streamsize));
     data += n;
     size -= n;
   } while (size != 0);
-  fmt::internal::write(os, buffer);
+  fmt::detail::write_buffer(os, buffer);
 }
 
 TEST(OStreamTest, Join) {
@@ -187,8 +188,8 @@ TEST(OStreamTest, Join) {
 
 #if FMT_USE_CONSTEXPR
 TEST(OStreamTest, ConstexprString) {
-  EXPECT_EQ("42", format(fmt("{}"), std::string("42")));
-  EXPECT_EQ("a string", format(fmt("{0}"), TestString("a string")));
+  EXPECT_EQ("42", format(FMT_STRING("{}"), std::string("42")));
+  EXPECT_EQ("a string", format(FMT_STRING("{0}"), TestString("a string")));
 }
 #endif
 
@@ -243,8 +244,7 @@ TEST(FormatTest, UDL) {
 }
 #endif
 
-template <typename T>
-struct convertible {
+template <typename T> struct convertible {
   T value;
   explicit convertible(const T& val) : value(val) {}
   operator T() const { return value; }
@@ -255,3 +255,55 @@ TEST(OStreamTest, DisableBuiltinOStreamOperators) {
   EXPECT_EQ(L"42", fmt::format(L"{:d}", convertible<unsigned short>(42)));
   EXPECT_EQ("foo", fmt::format("{}", convertible<const char*>("foo")));
 }
+
+struct explicitly_convertible_to_string_like {
+  template <typename String,
+            typename = typename std::enable_if<std::is_constructible<
+                String, const char*, size_t>::value>::type>
+  explicit operator String() const {
+    return String("foo", 3u);
+  }
+};
+
+std::ostream& operator<<(std::ostream& os,
+                         explicitly_convertible_to_string_like) {
+  return os << "bar";
+}
+
+TEST(OStreamTest, FormatExplicitlyConvertibleToStringLike) {
+  EXPECT_EQ("bar", fmt::format("{}", explicitly_convertible_to_string_like()));
+}
+
+#ifdef FMT_USE_STRING_VIEW
+struct explicitly_convertible_to_std_string_view {
+  explicit operator fmt::detail::std_string_view<char>() const {
+    return {"foo", 3u};
+  }
+};
+
+std::ostream& operator<<(std::ostream& os,
+                         explicitly_convertible_to_std_string_view) {
+  return os << "bar";
+}
+
+TEST(OStreamTest, FormatExplicitlyConvertibleToStdStringView) {
+  EXPECT_EQ("bar", fmt::format("{}", explicitly_convertible_to_string_like()));
+}
+
+#endif  // FMT_USE_STRING_VIEW
+
+struct copyfmt_test {};
+
+std::ostream& operator<<(std::ostream& os, copyfmt_test) {
+  std::ios ios(nullptr);
+  ios.copyfmt(os);
+  return os << "foo";
+}
+
+TEST(OStreamTest, CopyFmt) {
+  EXPECT_EQ("foo", fmt::format("{}", copyfmt_test()));
+}
+
+TEST(OStreamTest, CompileTimeString) {
+  EXPECT_EQ("42", fmt::format(FMT_STRING("{}"), 42));
+}

test/posix-mock-test.cc

@@ -11,13 +11,15 @@
 #endif
 
 #include "posix-mock.h"
-#include "../src/posix.cc"
 
 #include <errno.h>
 #include <fcntl.h>
+
 #include <climits>
 #include <memory>
 
+#include "../src/os.cc"
+
 #ifdef _WIN32
 #  include <io.h>
 #  undef max
@@ -30,7 +32,6 @@
 
 using fmt::buffered_file;
 using fmt::error_code;
-using fmt::file;
 
 using testing::_;
 using testing::Return;
@@ -48,11 +49,11 @@ int pipe_count;
 int fopen_count;
 int fclose_count;
 int fileno_count;
-std::size_t read_nbyte;
-std::size_t write_nbyte;
+size_t read_nbyte;
+size_t write_nbyte;
 bool sysconf_error;
 
-enum FStatSimulation { NONE, MAX_SIZE, ERROR } fstat_sim;
+enum { NONE, MAX_SIZE, ERROR } fstat_sim;
 }  // namespace
 
 #define EMULATE_EINTR(func, error_result) \
@@ -198,29 +199,32 @@ static void write_file(fmt::cstring_view filename, fmt::string_view content) {
   f.print("{}", content);
 }
 
+#if FMT_USE_FCNTL
+using fmt::file;
+
 TEST(UtilTest, GetPageSize) {
-#ifdef _WIN32
+#  ifdef _WIN32
   SYSTEM_INFO si = {};
   GetSystemInfo(&si);
   EXPECT_EQ(si.dwPageSize, fmt::getpagesize());
-#else
+#  else
   EXPECT_EQ(sysconf(_SC_PAGESIZE), fmt::getpagesize());
   sysconf_error = true;
   EXPECT_SYSTEM_ERROR(fmt::getpagesize(), EINVAL,
                       "cannot get memory page size");
   sysconf_error = false;
-#endif
+#  endif
 }
 
 TEST(FileTest, OpenRetry) {
-  write_file("test", "there must be something here");
+  write_file("temp", "there must be something here");
   std::unique_ptr<file> f{nullptr};
-  EXPECT_RETRY(f.reset(new file("test", file::RDONLY)), open,
-               "cannot open file test");
-#ifndef _WIN32
+  EXPECT_RETRY(f.reset(new file("temp", file::RDONLY)), open,
+               "cannot open file temp");
+#  ifndef _WIN32
   char c = 0;
   f->read(&c, 1);
-#endif
+#  endif
 }
 
 TEST(FileTest, CloseNoRetryInDtor) {
@@ -228,14 +232,15 @@ TEST(FileTest, CloseNoRetryInDtor) {
   file::pipe(read_end, write_end);
   std::unique_ptr<file> f(new file(std::move(read_end)));
   int saved_close_count = 0;
-  EXPECT_WRITE(stderr,
-               {
-                 close_count = 1;
-                 f.reset(nullptr);
-                 saved_close_count = close_count;
-                 close_count = 0;
-               },
-               format_system_error(EINTR, "cannot close file") + "\n");
+  EXPECT_WRITE(
+      stderr,
+      {
+        close_count = 1;
+        f.reset(nullptr);
+        saved_close_count = close_count;
+        close_count = 0;
+      },
+      format_system_error(EINTR, "cannot close file") + "\n");
   EXPECT_EQ(2, saved_close_count);
 }
 
@@ -250,26 +255,26 @@ TEST(FileTest, CloseNoRetry) {
 
 TEST(FileTest, Size) {
   std::string content = "top secret, destroy before reading";
-  write_file("test", content);
-  file f("test", file::RDONLY);
+  write_file("temp", content);
+  file f("temp", file::RDONLY);
   EXPECT_GE(f.size(), 0);
   EXPECT_EQ(content.size(), static_cast<unsigned long long>(f.size()));
-#ifdef _WIN32
+#  ifdef _WIN32
   fmt::memory_buffer message;
-  fmt::internal::format_windows_error(message, ERROR_ACCESS_DENIED,
-                                      "cannot get file size");
+  fmt::detail::format_windows_error(message, ERROR_ACCESS_DENIED,
+                                    "cannot get file size");
   fstat_sim = ERROR;
   EXPECT_THROW_MSG(f.size(), fmt::windows_error, fmt::to_string(message));
   fstat_sim = NONE;
-#else
+#  else
   f.close();
   EXPECT_SYSTEM_ERROR(f.size(), EBADF, "cannot get file attributes");
-#endif
+#  endif
 }
 
 TEST(FileTest, MaxSize) {
-  write_file("test", "");
-  file f("test", file::RDONLY);
+  write_file("temp", "");
+  file f("temp", file::RDONLY);
   fstat_sim = MAX_SIZE;
   EXPECT_GE(f.size(), 0);
   EXPECT_EQ(max_file_size(), f.size());
@@ -283,7 +288,7 @@ TEST(FileTest, ReadRetry) {
   write_end.write("test", SIZE);
   write_end.close();
   char buffer[SIZE];
-  std::size_t count = 0;
+  size_t count = 0;
   EXPECT_RETRY(count = read_end.read(buffer, SIZE), read,
                "cannot read from file");
   EXPECT_EQ_POSIX(static_cast<std::streamsize>(SIZE), count);
@@ -293,26 +298,26 @@ TEST(FileTest, WriteRetry) {
   file read_end, write_end;
   file::pipe(read_end, write_end);
   enum { SIZE = 4 };
-  std::size_t count = 0;
+  size_t count = 0;
   EXPECT_RETRY(count = write_end.write("test", SIZE), write,
                "cannot write to file");
   write_end.close();
-#ifndef _WIN32
+#  ifndef _WIN32
   EXPECT_EQ(static_cast<std::streamsize>(SIZE), count);
   char buffer[SIZE + 1];
   read_end.read(buffer, SIZE);
   buffer[SIZE] = '\0';
   EXPECT_STREQ("test", buffer);
-#endif
+#  endif
 }
 
-#ifdef _WIN32
+#  ifdef _WIN32
 TEST(FileTest, ConvertReadCount) {
   file read_end, write_end;
   file::pipe(read_end, write_end);
   char c;
-  std::size_t size = UINT_MAX;
-  if (sizeof(unsigned) != sizeof(std::size_t)) ++size;
+  size_t size = UINT_MAX;
+  if (sizeof(unsigned) != sizeof(size_t)) ++size;
   read_count = 1;
   read_nbyte = 0;
   EXPECT_THROW(read_end.read(&c, size), fmt::system_error);
@@ -324,15 +329,15 @@ TEST(FileTest, ConvertWriteCount) {
   file read_end, write_end;
   file::pipe(read_end, write_end);
   char c;
-  std::size_t size = UINT_MAX;
-  if (sizeof(unsigned) != sizeof(std::size_t)) ++size;
+  size_t size = UINT_MAX;
+  if (sizeof(unsigned) != sizeof(size_t)) ++size;
   write_count = 1;
   write_nbyte = 0;
   EXPECT_THROW(write_end.write(&c, size), fmt::system_error);
   write_count = 0;
   EXPECT_EQ(UINT_MAX, write_nbyte);
 }
-#endif
+#  endif
 
 TEST(FileTest, DupNoRetry) {
   int stdout_fd = FMT_POSIX(fileno(stdout));
@@ -357,11 +362,11 @@ TEST(FileTest, Dup2NoExceptRetry) {
   error_code ec;
   dup2_count = 1;
   f1.dup2(f2.descriptor(), ec);
-#ifndef _WIN32
+#  ifndef _WIN32
   EXPECT_EQ(4, dup2_count);
-#else
+#  else
   EXPECT_EQ(EINTR, ec.get());
-#endif
+#  endif
   dup2_count = 0;
 }
 
@@ -383,15 +388,15 @@ TEST(FileTest, FdopenNoRetry) {
 }
 
 TEST(BufferedFileTest, OpenRetry) {
-  write_file("test", "there must be something here");
+  write_file("temp", "there must be something here");
   std::unique_ptr<buffered_file> f{nullptr};
-  EXPECT_RETRY(f.reset(new buffered_file("test", "r")), fopen,
-               "cannot open file test");
-#ifndef _WIN32
+  EXPECT_RETRY(f.reset(new buffered_file("temp", "r")), fopen,
+               "cannot open file temp");
+#  ifndef _WIN32
   char c = 0;
   if (fread(&c, 1, 1, f->get()) < 1)
     throw fmt::system_error(errno, "fread failed");
-#endif
+#  endif
 }
 
 TEST(BufferedFileTest, CloseNoRetryInDtor) {
@@ -399,14 +404,15 @@ TEST(BufferedFileTest, CloseNoRetryInDtor) {
   file::pipe(read_end, write_end);
   std::unique_ptr<buffered_file> f(new buffered_file(read_end.fdopen("r")));
   int saved_fclose_count = 0;
-  EXPECT_WRITE(stderr,
-               {
-                 fclose_count = 1;
-                 f.reset(nullptr);
-                 saved_fclose_count = fclose_count;
-                 fclose_count = 0;
-               },
-               format_system_error(EINTR, "cannot close file") + "\n");
+  EXPECT_WRITE(
+      stderr,
+      {
+        fclose_count = 1;
+        f.reset(nullptr);
+        saved_fclose_count = fclose_count;
+        fclose_count = 0;
+      },
+      format_system_error(EINTR, "cannot close file") + "\n");
   EXPECT_EQ(2, saved_fclose_count);
 }
 
@@ -429,34 +435,35 @@ TEST(BufferedFileTest, FilenoNoRetry) {
   EXPECT_EQ(2, fileno_count);
   fileno_count = 0;
 }
+#endif  // FMT_USE_FCNTL
 
-struct TestMock {
-  static TestMock* instance;
-} * TestMock::instance;
+struct test_mock {
+  static test_mock* instance;
+} * test_mock::instance;
 
 TEST(ScopedMock, Scope) {
   {
-    ScopedMock<TestMock> mock;
-    EXPECT_EQ(&mock, TestMock::instance);
-    TestMock& copy = mock;
+    ScopedMock<test_mock> mock;
+    EXPECT_EQ(&mock, test_mock::instance);
+    test_mock& copy = mock;
     static_cast<void>(copy);
   }
-  EXPECT_EQ(nullptr, TestMock::instance);
+  EXPECT_EQ(nullptr, test_mock::instance);
 }
 
 #ifdef FMT_LOCALE
 
-typedef fmt::Locale::type LocaleType;
+typedef fmt::locale::type locale_type;
 
-struct LocaleMock {
-  static LocaleMock* instance;
-  MOCK_METHOD3(newlocale, LocaleType(int category_mask, const char* locale,
-                                     LocaleType base));
-  MOCK_METHOD1(freelocale, void(LocaleType locale));
+struct locale_mock {
+  static locale_mock* instance;
+  MOCK_METHOD3(newlocale, locale_type(int category_mask, const char* locale,
+                                      locale_type base));
+  MOCK_METHOD1(freelocale, void(locale_type locale));
 
   MOCK_METHOD3(strtod_l,
-               double(const char* nptr, char** endptr, LocaleType locale));
-} * LocaleMock::instance;
+               double(const char* nptr, char** endptr, locale_type locale));
+} * locale_mock::instance;
 
 #  ifdef _MSC_VER
 #    pragma warning(push)
@@ -467,15 +474,15 @@ struct LocaleMock {
 #    endif
 
 _locale_t _create_locale(int category, const char* locale) {
-  return LocaleMock::instance->newlocale(category, locale, 0);
+  return locale_mock::instance->newlocale(category, locale, 0);
 }
 
 void _free_locale(_locale_t locale) {
-  LocaleMock::instance->freelocale(locale);
+  locale_mock::instance->freelocale(locale);
 }
 
 double _strtod_l(const char* nptr, char** endptr, _locale_t locale) {
-  return LocaleMock::instance->strtod_l(nptr, endptr, locale);
+  return locale_mock::instance->strtod_l(nptr, endptr, locale);
 }
 #    ifdef __clang__
 #      pragma clang diagnostic pop
@@ -489,11 +496,6 @@ double _strtod_l(const char* nptr, char** endptr, _locale_t locale) {
 #    define FMT_LOCALE_THROW
 #  endif
 
-LocaleType newlocale(int category_mask, const char* locale,
-                     LocaleType base) FMT_LOCALE_THROW {
-  return LocaleMock::instance->newlocale(category_mask, locale, base);
-}
-
 #  if defined(__APPLE__) || \
       (defined(__FreeBSD__) && __FreeBSD_version < 1200002)
 typedef int FreeLocaleResult;
@@ -501,49 +503,55 @@ typedef int FreeLocaleResult;
 typedef void FreeLocaleResult;
 #  endif
 
-FreeLocaleResult freelocale(LocaleType locale) FMT_LOCALE_THROW {
-  LocaleMock::instance->freelocale(locale);
+FreeLocaleResult freelocale(locale_type locale) FMT_LOCALE_THROW {
+  locale_mock::instance->freelocale(locale);
   return FreeLocaleResult();
 }
 
 double strtod_l(const char* nptr, char** endptr,
-                LocaleType locale) FMT_LOCALE_THROW {
-  return LocaleMock::instance->strtod_l(nptr, endptr, locale);
+                locale_type locale) FMT_LOCALE_THROW {
+  return locale_mock::instance->strtod_l(nptr, endptr, locale);
 }
 
 #  undef FMT_LOCALE_THROW
 
-TEST(LocaleTest, LocaleMock) {
-  ScopedMock<LocaleMock> mock;
-  LocaleType locale = reinterpret_cast<LocaleType>(11);
-  EXPECT_CALL(mock, newlocale(222, StrEq("foo"), locale));
-  newlocale(222, "foo", locale);
+#  ifndef _WIN32
+locale_t test::newlocale(int category_mask, const char* locale, locale_t base) {
+  return locale_mock::instance->newlocale(category_mask, locale, base);
 }
 
+TEST(LocaleTest, LocaleMock) {
+  ScopedMock<locale_mock> mock;
+  locale_type locale = reinterpret_cast<locale_type>(11);
+  EXPECT_CALL(mock, newlocale(222, StrEq("foo"), locale));
+  FMT_SYSTEM(newlocale(222, "foo", locale));
+}
+#  endif
+
 TEST(LocaleTest, Locale) {
 #  ifndef LC_NUMERIC_MASK
   enum { LC_NUMERIC_MASK = LC_NUMERIC };
 #  endif
-  ScopedMock<LocaleMock> mock;
-  LocaleType impl = reinterpret_cast<LocaleType>(42);
+  ScopedMock<locale_mock> mock;
+  locale_type impl = reinterpret_cast<locale_type>(42);
   EXPECT_CALL(mock, newlocale(LC_NUMERIC_MASK, StrEq("C"), nullptr))
       .WillOnce(Return(impl));
   EXPECT_CALL(mock, freelocale(impl));
-  fmt::Locale locale;
-  EXPECT_EQ(impl, locale.get());
+  fmt::locale loc;
+  EXPECT_EQ(impl, loc.get());
 }
 
 TEST(LocaleTest, Strtod) {
-  ScopedMock<LocaleMock> mock;
+  ScopedMock<locale_mock> mock;
   EXPECT_CALL(mock, newlocale(_, _, _))
-      .WillOnce(Return(reinterpret_cast<LocaleType>(42)));
+      .WillOnce(Return(reinterpret_cast<locale_type>(42)));
   EXPECT_CALL(mock, freelocale(_));
-  fmt::Locale locale;
+  fmt::locale loc;
   const char* str = "4.2";
   char end = 'x';
-  EXPECT_CALL(mock, strtod_l(str, _, locale.get()))
+  EXPECT_CALL(mock, strtod_l(str, _, loc.get()))
       .WillOnce(testing::DoAll(testing::SetArgPointee<1>(&end), Return(777)));
-  EXPECT_EQ(777, locale.strtod(str));
+  EXPECT_EQ(777, loc.strtod(str));
   EXPECT_EQ(&end, str);
 }
 

test/posix-mock.h

@@ -9,7 +9,11 @@
 #define FMT_POSIX_TEST_H
 
 #include <errno.h>
+#include <locale.h>
 #include <stdio.h>
+#ifdef __APPLE__
+#  include <xlocale.h>
+#endif
 
 #ifdef _WIN32
 #  include <windows.h>
@@ -62,6 +66,10 @@ int pipe(int* pfds, unsigned psize, int textmode);
 FILE* fopen(const char* filename, const char* mode);
 int fclose(FILE* stream);
 int(fileno)(FILE* stream);
+
+#if defined(FMT_LOCALE) && !defined(_WIN32)
+locale_t newlocale(int category_mask, const char* locale, locale_t base);
+#endif
 }  // namespace test
 
 #define FMT_SYSTEM(call) test::call

test/printf-test.cc

@@ -5,18 +5,19 @@
 //
 // For the license information refer to format.h.
 
+#include "fmt/printf.h"
+
 #include <cctype>
 #include <climits>
 #include <cstring>
 
 #include "fmt/core.h"
-#include "fmt/printf.h"
 #include "gtest-extra.h"
 #include "util.h"
 
 using fmt::format;
 using fmt::format_error;
-using fmt::internal::max_value;
+using fmt::detail::max_value;
 
 const unsigned BIG_NUM = INT_MAX + 1u;
 
@@ -112,14 +113,13 @@ TEST(PrintfTest, SwitchArgIndexing) {
 
 TEST(PrintfTest, InvalidArgIndex) {
   EXPECT_THROW_MSG(test_sprintf("%0$d", 42), format_error,
-                   "argument index out of range");
+                   "argument not found");
   EXPECT_THROW_MSG(test_sprintf("%2$d", 42), format_error,
-                   "argument index out of range");
+                   "argument not found");
   EXPECT_THROW_MSG(test_sprintf(format("%{}$d", INT_MAX), 42), format_error,
-                   "argument index out of range");
+                   "argument not found");
 
-  EXPECT_THROW_MSG(test_sprintf("%2$", 42), format_error,
-                   "argument index out of range");
+  EXPECT_THROW_MSG(test_sprintf("%2$", 42), format_error, "argument not found");
   EXPECT_THROW_MSG(test_sprintf(format("%{}$d", BIG_NUM), 42), format_error,
                    "number is too big");
 }
@@ -139,8 +139,11 @@ TEST(PrintfTest, ZeroFlag) {
 
   EXPECT_PRINTF("+00042", "%00+6d", 42);
 
+  EXPECT_PRINTF("   42", "%05.d", 42);
+  EXPECT_PRINTF(" 0042", "%05.4d", 42);
+
   // '0' flag is ignored for non-numeric types.
-  EXPECT_PRINTF("0000x", "%05c", 'x');
+  EXPECT_PRINTF("    x", "%05c", 'x');
 }
 
 TEST(PrintfTest, PlusFlag) {
@@ -151,11 +154,38 @@ TEST(PrintfTest, PlusFlag) {
 
   // '+' flag is ignored for non-numeric types.
   EXPECT_PRINTF("x", "%+c", 'x');
+
+  // '+' flag wins over space flag
+  EXPECT_PRINTF("+42", "%+ d", 42);
+  EXPECT_PRINTF("-42", "%+ d", -42);
+  EXPECT_PRINTF("+42", "% +d", 42);
+  EXPECT_PRINTF("-42", "% +d", -42);
+  EXPECT_PRINTF("+0042", "% +05d", 42);
+  EXPECT_PRINTF("+0042", "%0+ 5d", 42);
+
+  // '+' flag and space flag are both ignored for non-numeric types.
+  EXPECT_PRINTF("x", "%+ c", 'x');
+  EXPECT_PRINTF("x", "% +c", 'x');
 }
 
 TEST(PrintfTest, MinusFlag) {
   EXPECT_PRINTF("abc  ", "%-5s", "abc");
   EXPECT_PRINTF("abc  ", "%0--5s", "abc");
+
+  EXPECT_PRINTF("7    ", "%-5d", 7);
+  EXPECT_PRINTF("97   ", "%-5hhi", 'a');
+  EXPECT_PRINTF("a    ", "%-5c", 'a');
+
+  // '0' flag is ignored if '-' flag is given
+  EXPECT_PRINTF("7    ", "%-05d", 7);
+  EXPECT_PRINTF("7    ", "%0-5d", 7);
+  EXPECT_PRINTF("a    ", "%-05c", 'a');
+  EXPECT_PRINTF("a    ", "%0-5c", 'a');
+  EXPECT_PRINTF("97   ", "%-05hhi", 'a');
+  EXPECT_PRINTF("97   ", "%0-5hhi", 'a');
+
+  // '-' and space flag don't interfere
+  EXPECT_PRINTF(" 42", "%- d", 42);
 }
 
 TEST(PrintfTest, SpaceFlag) {
@@ -221,8 +251,7 @@ TEST(PrintfTest, DynamicWidth) {
   EXPECT_EQ("42   ", test_sprintf("%*d", -5, 42));
   EXPECT_THROW_MSG(test_sprintf("%*d", 5.0, 42), format_error,
                    "width is not integer");
-  EXPECT_THROW_MSG(test_sprintf("%*d"), format_error,
-                   "argument index out of range");
+  EXPECT_THROW_MSG(test_sprintf("%*d"), format_error, "argument not found");
   EXPECT_THROW_MSG(test_sprintf("%*d", BIG_NUM, 42), format_error,
                    "number is too big");
 }
@@ -258,6 +287,11 @@ TEST(PrintfTest, FloatPrecision) {
   EXPECT_PRINTF(buffer, "%.3a", 1234.5678);
 }
 
+TEST(PrintfTest, StringPrecision) {
+  char test[] = {'H', 'e', 'l', 'l', 'o'};
+  EXPECT_EQ(fmt::sprintf("%.4s", test), "Hell");
+}
+
 TEST(PrintfTest, IgnorePrecisionForNonNumericArg) {
   EXPECT_PRINTF("abc", "%.5s", "abc");
 }
@@ -267,8 +301,7 @@ TEST(PrintfTest, DynamicPrecision) {
   EXPECT_EQ("42", test_sprintf("%.*d", -5, 42));
   EXPECT_THROW_MSG(test_sprintf("%.*d", 5.0, 42), format_error,
                    "precision is not integer");
-  EXPECT_THROW_MSG(test_sprintf("%.*d"), format_error,
-                   "argument index out of range");
+  EXPECT_THROW_MSG(test_sprintf("%.*d"), format_error, "argument not found");
   EXPECT_THROW_MSG(test_sprintf("%.*d", BIG_NUM, 42), format_error,
                    "number is too big");
   if (sizeof(long long) != sizeof(int)) {
@@ -297,18 +330,18 @@ void TestLength(const char* length_spec, U value) {
   unsigned long long unsigned_value = 0;
   // Apply integer promotion to the argument.
   unsigned long long max = max_value<U>();
-  using fmt::internal::const_check;
+  using fmt::detail::const_check;
   if (const_check(max <= static_cast<unsigned>(max_value<int>()))) {
     signed_value = static_cast<int>(value);
-    unsigned_value = static_cast<unsigned>(value);
+    unsigned_value = static_cast<unsigned long long>(value);
   } else if (const_check(max <= max_value<unsigned>())) {
     signed_value = static_cast<unsigned>(value);
-    unsigned_value = static_cast<unsigned>(value);
+    unsigned_value = static_cast<unsigned long long>(value);
   }
   if (sizeof(U) <= sizeof(int) && sizeof(int) < sizeof(T)) {
     signed_value = static_cast<long long>(value);
-    unsigned_value =
-        static_cast<typename std::make_unsigned<unsigned>::type>(value);
+    unsigned_value = static_cast<unsigned long long>(
+        static_cast<typename std::make_unsigned<unsigned>::type>(value));
   } else {
     signed_value = static_cast<typename make_signed<T>::type>(value);
     unsigned_value = static_cast<typename std::make_unsigned<T>::type>(value);
@@ -337,7 +370,9 @@ template <typename T> void TestLength(const char* length_spec) {
   TestLength<T>(length_spec, -42);
   TestLength<T>(length_spec, min);
   TestLength<T>(length_spec, max);
-  TestLength<T>(length_spec, static_cast<long long>(min) - 1);
+  long long long_long_min = std::numeric_limits<long long>::min();
+  if (static_cast<long long>(min) > long_long_min)
+    TestLength<T>(length_spec, static_cast<long long>(min) - 1);
   unsigned long long long_long_max = max_value<long long>();
   if (static_cast<unsigned long long>(max) < long_long_max)
     TestLength<T>(length_spec, static_cast<long long>(max) + 1);
@@ -364,7 +399,7 @@ TEST(PrintfTest, Length) {
   TestLength<long long>("ll");
   TestLength<unsigned long long>("ll");
   TestLength<intmax_t>("j");
-  TestLength<std::size_t>("z");
+  TestLength<size_t>("z");
   TestLength<std::ptrdiff_t>("t");
   long double max = max_value<long double>();
   EXPECT_PRINTF(fmt::format("{:.6}", max), "%g", max);
@@ -408,6 +443,7 @@ TEST(PrintfTest, Float) {
   EXPECT_PRINTF("392.65", "%G", 392.65);
   EXPECT_PRINTF("392", "%g", 392.0);
   EXPECT_PRINTF("392", "%G", 392.0);
+  EXPECT_PRINTF("4.56e-07", "%g", 0.000000456);
   safe_sprintf(buffer, "%a", -392.65);
   EXPECT_EQ(buffer, format("{:a}", -392.65));
   safe_sprintf(buffer, "%A", -392.65);
@@ -443,6 +479,12 @@ TEST(PrintfTest, String) {
   EXPECT_PRINTF(L"    (null)", L"%10s", null_wstr);
 }
 
+TEST(PrintfTest, UCharString) {
+  unsigned char str[] = "test";
+  unsigned char* pstr = str;
+  EXPECT_EQ("test", fmt::sprintf("%s", pstr));
+}
+
 TEST(PrintfTest, Pointer) {
   int n;
   void* p = &n;
@@ -470,11 +512,15 @@ TEST(PrintfTest, Location) {
   // TODO: test %n
 }
 
-enum E { A = 42 };
+enum test_enum { answer = 42 };
 
-TEST(PrintfTest, Enum) { EXPECT_PRINTF("42", "%d", A); }
+TEST(PrintfTest, Enum) {
+  EXPECT_PRINTF("42", "%d", answer);
+  volatile test_enum volatile_enum = answer;
+  EXPECT_PRINTF("42", "%d", volatile_enum);
+}
 
-#if FMT_USE_FILE_DESCRIPTORS
+#if FMT_USE_FCNTL
 TEST(PrintfTest, Examples) {
   const char* weekday = "Thursday";
   const char* month = "August";
@@ -561,51 +607,22 @@ TEST(PrintfTest, VSPrintfMakeWArgsExample) {
 #endif
 }
 
-typedef fmt::printf_arg_formatter<fmt::buffer_range<char>> formatter_t;
-typedef fmt::basic_printf_context<formatter_t::iterator, char> context_t;
+TEST(PrintfTest, PrintfDetermineOutputSize) {
+  using backit = std::back_insert_iterator<std::vector<char>>;
+  using truncated_printf_context =
+      fmt::basic_printf_context<fmt::detail::truncating_iterator<backit>, char>;
 
-// A custom printf argument formatter that doesn't print `-` for floating-point
-// values rounded to 0.
-class custom_printf_arg_formatter : public formatter_t {
- public:
-  using formatter_t::iterator;
+  auto v = std::vector<char>{};
+  auto it = std::back_inserter(v);
 
-  custom_printf_arg_formatter(formatter_t::iterator iter,
-                              formatter_t::format_specs& specs, context_t& ctx)
-      : formatter_t(iter, specs, ctx) {}
+  const auto format_string = "%s";
+  const auto format_arg = "Hello";
+  const auto expected_size = fmt::sprintf(format_string, format_arg).size();
 
-  using formatter_t::operator();
-
-#if FMT_MSC_VER > 0 && FMT_MSC_VER <= 1804
-  template <typename T, FMT_ENABLE_IF(std::is_floating_point<T>::value)>
-  iterator operator()(T value){
-#else
-  iterator operator()(double value) {
-#endif
-      // Comparing a float to 0.0 is safe.
-      if (round(value * pow(10, specs()->precision)) == 0.0) value = 0;
-  return formatter_t::operator()(value);
-}
-}
-;
-
-typedef fmt::basic_format_args<context_t> format_args_t;
-
-std::string custom_vformat(fmt::string_view format_str, format_args_t args) {
-  fmt::memory_buffer buffer;
-  fmt::vprintf<custom_printf_arg_formatter>(buffer, 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_printf_args(args...);
-  return custom_vformat(format_str, {va});
-}
-
-TEST(PrintfTest, CustomFormat) {
-  EXPECT_EQ("0.00", custom_format("%.2f", -.00001));
-  EXPECT_EQ("0.00", custom_format("%.2f", .00001));
-  EXPECT_EQ("1.00", custom_format("%.2f", 1.00001));
-  EXPECT_EQ("-1.00", custom_format("%.2f", -1.00001));
+  EXPECT_EQ((truncated_printf_context(
+                 fmt::detail::truncating_iterator<backit>(it, 0), format_string,
+                 fmt::make_format_args<truncated_printf_context>(format_arg))
+                 .format()
+                 .count()),
+            expected_size);
 }

test/ranges-test.cc

@@ -10,6 +10,7 @@
 // {fmt} support for ranges, containers and types tuple interface.
 
 #include "fmt/ranges.h"
+
 #include "gtest.h"
 
 // Check if  'if constexpr' is supported.
@@ -44,9 +45,10 @@ TEST(RangesTest, FormatPair) {
 }
 
 TEST(RangesTest, FormatTuple) {
-  std::tuple<int64_t, float, std::string, char> tu1{42, 1.5f, "this is tuple",
-                                                    'i'};
-  EXPECT_EQ("(42, 1.5, \"this is tuple\", 'i')", fmt::format("{}", tu1));
+  std::tuple<int64_t, float, std::string, char> t{42, 1.5f, "this is tuple",
+                                                  'i'};
+  EXPECT_EQ("(42, 1.5, \"this is tuple\", 'i')", fmt::format("{}", t));
+  EXPECT_EQ("()", fmt::format("{}", std::tuple<>()));
 }
 
 TEST(RangesTest, JoinTuple) {
@@ -68,10 +70,16 @@ TEST(RangesTest, JoinTuple) {
   EXPECT_EQ("4.0", fmt::format("{}", fmt::join(t4, "/")));
 }
 
+TEST(RangesTest, JoinInitializerList) {
+  EXPECT_EQ("1, 2, 3", fmt::format("{}", fmt::join({1, 2, 3}, ", ")));
+  EXPECT_EQ("fmt rocks !",
+            fmt::format("{}", fmt::join({"fmt", "rocks", "!"}, " ")));
+}
+
 struct my_struct {
   int32_t i;
   std::string str;  // can throw
-  template <std::size_t N> decltype(auto) get() const noexcept {
+  template <size_t N> decltype(auto) get() const noexcept {
     if constexpr (N == 0)
       return i;
     else if constexpr (N == 1)
@@ -79,16 +87,15 @@ struct my_struct {
   }
 };
 
-template <std::size_t N> decltype(auto) get(const my_struct& s) noexcept {
+template <size_t N> decltype(auto) get(const my_struct& s) noexcept {
   return s.get<N>();
 }
 
 namespace std {
 
-template <>
-struct tuple_size<my_struct> : std::integral_constant<std::size_t, 2> {};
+template <> struct tuple_size<my_struct> : std::integral_constant<size_t, 2> {};
 
-template <std::size_t N> struct tuple_element<N, my_struct> {
+template <size_t N> struct tuple_element<N, my_struct> {
   using type = decltype(std::declval<my_struct>().get<N>());
 };
 
@@ -132,3 +139,17 @@ TEST(RangesTest, FormatStringLike) {
   EXPECT_EQ("foo", fmt::format("{}", string_like()));
 }
 #endif  // FMT_USE_STRING_VIEW
+
+struct zstring_sentinel {};
+bool operator==(const char* p, zstring_sentinel) { return *p == '\0'; }
+bool operator!=(const char* p, zstring_sentinel) { return *p != '\0'; }
+struct zstring {
+  const char* p;
+  const char* begin() const { return p; }
+  zstring_sentinel end() const { return {}; }
+};
+TEST(RangesTest, JoinSentinel) {
+  zstring hello{"hello"};
+  EXPECT_EQ("{'h', 'e', 'l', 'l', 'o'}", fmt::format("{}", hello));
+  EXPECT_EQ("h_e_l_l_o", fmt::format("{}", fmt::join(hello, "_")));
+}

test/scan-test.cc

@@ -5,12 +5,14 @@
 //
 // For the license information refer to format.h.
 
+#include "scan.h"
+
 #include <time.h>
+
 #include <climits>
 
 #include "gmock.h"
 #include "gtest-extra.h"
-#include "scan.h"
 
 TEST(ScanTest, ReadText) {
   fmt::string_view s = "foo";
@@ -73,7 +75,7 @@ template <> struct scanner<tm> {
     if (it != ctx.end() && *it == ':') ++it;
     auto end = it;
     while (end != ctx.end() && *end != '}') ++end;
-    format.reserve(internal::to_unsigned(end - it + 1));
+    format.reserve(detail::to_unsigned(end - it + 1));
     format.append(it, end);
     format.push_back('\0');
     return end;

test/scan.h

@@ -6,6 +6,8 @@
 // For the license information refer to format.h.
 
 #include <array>
+#include <cassert>
+#include <climits>
 
 #include "fmt/format.h"
 
@@ -29,7 +31,7 @@ class scan_parse_context {
   FMT_CONSTEXPR iterator end() const { return format_.end(); }
 
   void advance_to(iterator it) {
-    format_.remove_prefix(internal::to_unsigned(it - begin()));
+    format_.remove_prefix(detail::to_unsigned(it - begin()));
   }
 };
 
@@ -46,11 +48,11 @@ struct scan_context {
   iterator end() const { return begin() + input_.size(); }
 
   void advance_to(iterator it) {
-    input_.remove_prefix(internal::to_unsigned(it - begin()));
+    input_.remove_prefix(detail::to_unsigned(it - begin()));
   }
 };
 
-namespace internal {
+namespace detail {
 enum class scan_type {
   none_type,
   int_type,
@@ -105,20 +107,20 @@ class scan_arg {
     ctx.advance_to(s.scan(*static_cast<T*>(arg), ctx));
   }
 };
-}  // namespace internal
+}  // namespace detail
 
 struct scan_args {
   int size;
-  const internal::scan_arg* data;
+  const detail::scan_arg* data;
 
   template <size_t N>
-  scan_args(const std::array<internal::scan_arg, N>& store)
+  scan_args(const std::array<detail::scan_arg, N>& store)
       : size(N), data(store.data()) {
     static_assert(N < INT_MAX, "too many arguments");
   }
 };
 
-namespace internal {
+namespace detail {
 
 struct scan_handler : error_handler {
  private:
@@ -135,21 +137,20 @@ struct scan_handler : error_handler {
       char c = *it++;
       if (c < '0' || c > '9') on_error("invalid input");
       // TODO: check overflow
-      value = value * 10 + (c - '0');
+      value = value * 10 + static_cast<unsigned>(c - '0');
     }
     scan_ctx_.advance_to(it);
     return value;
   }
 
   template <typename T = int> T read_int() {
-    T value = 0;
     auto it = scan_ctx_.begin(), end = scan_ctx_.end();
     bool negative = it != end && *it == '-';
     if (negative) ++it;
     scan_ctx_.advance_to(it);
-    value = read_uint<typename std::make_unsigned<T>::type>();
-    if (negative) value = -value;
-    return value;
+    const auto value = read_uint<typename std::make_unsigned<T>::type>();
+    if (negative) return -static_cast<T>(value);
+    return static_cast<T>(value);
   }
 
  public:
@@ -159,7 +160,7 @@ struct scan_handler : error_handler {
   const char* pos() const { return scan_ctx_.begin(); }
 
   void on_text(const char* begin, const char* end) {
-    auto size = end - begin;
+    auto size = to_unsigned(end - begin);
     auto it = scan_ctx_.begin();
     if (it + size > scan_ctx_.end() ||
         !std::equal(begin, end, make_checked(it, size))) {
@@ -168,14 +169,15 @@ struct scan_handler : error_handler {
     scan_ctx_.advance_to(it + size);
   }
 
-  void on_arg_id() { on_arg_id(next_arg_id_++); }
-  void on_arg_id(int id) {
+  int on_arg_id() { return on_arg_id(next_arg_id_++); }
+  int on_arg_id(int id) {
     if (id >= args_.size) on_error("argument index out of range");
     arg_ = args_.data[id];
+    return id;
   }
-  void on_arg_id(string_view) { on_error("invalid format"); }
+  int on_arg_id(string_view) { return on_error("invalid format"), 0; }
 
-  void on_replacement_field(const char*) {
+  void on_replacement_field(int, const char*) {
     auto it = scan_ctx_.begin(), end = scan_ctx_.end();
     switch (arg_.type) {
     case scan_type::int_type:
@@ -197,33 +199,34 @@ struct scan_handler : error_handler {
     case scan_type::string_view_type: {
       auto s = it;
       while (it != end && *it != ' ') ++it;
-      *arg_.string_view = fmt::string_view(s, it - s);
+      *arg_.string_view = fmt::string_view(s, to_unsigned(it - s));
       scan_ctx_.advance_to(it);
       break;
     }
-    default:
+    case scan_type::none_type:
+    case scan_type::custom_type:
       assert(false);
     }
   }
 
-  const char* on_format_specs(const char* begin, const char*) {
+  const char* on_format_specs(int, const char* begin, const char*) {
     if (arg_.type != scan_type::custom_type) return begin;
     parse_ctx_.advance_to(begin);
     arg_.custom.scan(arg_.custom.value, parse_ctx_, scan_ctx_);
     return parse_ctx_.begin();
   }
 };
-}  // namespace internal
+}  // namespace detail
 
 template <typename... Args>
-std::array<internal::scan_arg, sizeof...(Args)> make_scan_args(Args&... args) {
+std::array<detail::scan_arg, sizeof...(Args)> make_scan_args(Args&... args) {
   return {{args...}};
 }
 
 string_view::iterator vscan(string_view input, string_view format_str,
                             scan_args args) {
-  internal::scan_handler h(format_str, input, args);
-  internal::parse_format_string<false>(format_str, h);
+  detail::scan_handler h(format_str, input, args);
+  detail::parse_format_string<false>(format_str, h);
   return input.begin() + (h.pos() - &*input.begin());
 }
 

test/std-format-test.cc

@@ -1,4 +1,5 @@
 #include <format>
+
 #include "gtest.h"
 
 TEST(StdFormatTest, Escaping) {
@@ -29,8 +30,8 @@ TEST(StdFormatTest, Alignment) {
   string s4 = format("{:*^6}", 'x');  // s4 == "**x***"
   // Error: '=' with charT and no integer presentation type
   EXPECT_THROW(string s5 = format("{:=6}", 'x'), std::format_error);
-  string s6 = format("{:6d}", c);       // s6 == "   120"
-  string s7 = format("{:6}", true);     // s9 == "true  "
+  string s6 = format("{:6d}", c);    // s6 == "   120"
+  string s7 = format("{:6}", true);  // s9 == "true  "
   EXPECT_EQ(s0, "    42");
   EXPECT_EQ(s1, "x     ");
   EXPECT_EQ(s2, "x*****");
@@ -61,11 +62,11 @@ TEST(StdFormatTest, Int) {
   string s0 = format("{}", 42);                       // s0 == "42"
   string s1 = format("{0:b} {0:d} {0:o} {0:x}", 42);  // s1 == "101010 42 52 2a"
   string s2 = format("{0:#x} {0:#X}", 42);            // s2 == "0x2a 0X2A"
-  string s3 = format("{:n}", 1234);  // s3 == "1,234" (depends on the locale)
+  string s3 = format("{:L}", 1234);  // s3 == "1234" (depends on the locale)
   EXPECT_EQ(s0, "42");
   EXPECT_EQ(s1, "101010 42 52 2a");
   EXPECT_EQ(s2, "0x2a 0X2A");
-  EXPECT_EQ(s3, "1,234");
+  EXPECT_EQ(s3, "1234");
 }
 
 #include <format>
@@ -123,7 +124,7 @@ template <> struct std::formatter<S> {
           if constexpr (!is_integral_v<type> || is_same_v<type, bool>)
             throw format_error("width is not integral");
           // else if (value < 0 || value > numeric_limits<int>::max())
-          else if (fmt::internal::is_negative(value) ||
+          else if (fmt::detail::is_negative(value) ||
                    value > numeric_limits<int>::max())
             throw format_error("invalid width");
           else

test/test-assert.h

@@ -9,13 +9,19 @@
 #define FMT_TEST_ASSERT_H_
 
 #include <stdexcept>
+
 #include "gtest.h"
 
 class assertion_failure : public std::logic_error {
  public:
   explicit assertion_failure(const char* message) : std::logic_error(message) {}
+
+ private:
+  virtual void avoid_weak_vtable();
 };
 
+void assertion_failure::avoid_weak_vtable() {}
+
 #define FMT_ASSERT(condition, message) \
   if (!(condition)) throw assertion_failure(message);
 

test/test-main.cc

@@ -6,6 +6,7 @@
 // For the license information refer to format.h.
 
 #include <cstdlib>
+
 #include "gtest.h"
 
 #ifdef _WIN32

test/util.cc

@@ -6,6 +6,7 @@
 // For the license information refer to format.h.
 
 #include "util.h"
+
 #include <cstring>
 
 void increment(char* s) {
@@ -33,11 +34,17 @@ std::string get_system_error(int error_code) {
 const char* const FILE_CONTENT = "Don't panic!";
 
 fmt::buffered_file open_buffered_file(FILE** fp) {
+#if FMT_USE_FCNTL
   fmt::file read_end, write_end;
   fmt::file::pipe(read_end, write_end);
   write_end.write(FILE_CONTENT, std::strlen(FILE_CONTENT));
   write_end.close();
   fmt::buffered_file f = read_end.fdopen("r");
   if (fp) *fp = f.get();
+#else
+  fmt::buffered_file f("test-file", "w");
+  fputs(FILE_CONTENT, f.get());
+  if (fp) *fp = f.get();
+#endif
   return f;
 }

test/util.h

@@ -9,7 +9,7 @@
 #include <cstdio>
 #include <string>
 
-#include "fmt/posix.h"
+#include "fmt/os.h"
 
 enum { BUFFER_SIZE = 256 };
 
@@ -19,7 +19,7 @@ enum { BUFFER_SIZE = 256 };
 #  define FMT_VSNPRINTF vsnprintf
 #endif
 
-template <std::size_t SIZE>
+template <size_t SIZE>
 void safe_sprintf(char (&buffer)[SIZE], const char* format, ...) {
   std::va_list args;
   va_start(args, format);