Merge pull request #338 from Gravecat/mingw-fix

Fixes compilation on GCC/MinGW

.bazelrc

@@ -0,0 +1 @@
+build --cxxopt="--std=c++17"

.clang-format

@@ -1,2 +1,4 @@
 BasedOnStyle: LLVM
 SortIncludes: false
+SeparateDefinitionBlocks: Always
+MaxEmptyLinesToKeep: 1

.github/pull_request_template.md

@@ -1,3 +1,5 @@
+We have benchmarks, please consider running them: [see our README for details](https://github.com/fastfloat/fast_float/blob/main/README.md#benchmarking). We expect you to run our benchmarks if you make claims with respect to the performance.
+
 
 Our CI tests check formatting automating. If such a test fails, please consider running the bash script:
 

.github/workflows/alpine.yml

@@ -18,7 +18,7 @@ jobs:
           - riscv64
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v4
+        uses: actions/checkout@v5
 
       - name: Install latest Alpine Linux for ${{ matrix.arch }}
         uses: jirutka/setup-alpine@v1

.github/workflows/amalgamate-ubuntu24.yml

@@ -1,12 +1,12 @@
-name: Amalgamate Ubuntu 20.04 CI (GCC 9)
+name: Amalgamate Ubuntu 24.04 CI
 
 on: [push, pull_request]
 
 jobs:
   ubuntu-build:
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-24.04
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v5
       - name: Compile with amalgamation
         run: |
           mkdir build &&

.github/workflows/cifuzz.yml

@@ -20,14 +20,14 @@ jobs:
        fuzz-seconds: 300
        output-sarif: true
    - name: Upload Crash
-     uses: actions/upload-artifact@v4
+     uses: actions/upload-artifact@v5
      if: failure() && steps.build.outcome == 'success'
      with:
        name: artifacts
        path: ./out/artifacts
    - name: Upload Sarif
      if: always() && steps.build.outcome == 'success'
-     uses: github/codeql-action/upload-sarif@v3
+     uses: github/codeql-action/upload-sarif@v4
      with:
       # Path to SARIF file relative to the root of the repository
       sarif_file: cifuzz-sarif/results.sarif

.github/workflows/emscripten.yml

@@ -0,0 +1,17 @@
+on: [push, pull_request]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@ff7abcd0c3c05ccf6adc123a8cd1fd4fb30fb493 # v4.2.2
+      - uses: actions/setup-node@2028fbc5c25fe9cf00d9f06a71cc4710d4507903 # v6.0.0
+      - uses: mymindstorm/setup-emsdk@6ab9eb1bda2574c4ddb79809fc9247783eaf9021 # v14
+      - name: Verify
+        run: emcc -v
+      - name: Checkout
+        uses: actions/checkout@ff7abcd0c3c05ccf6adc123a8cd1fd4fb30fb493 # v3.6.0
+      - name: Configure
+        run: emcmake cmake -B build
+      - name: Build # We build but do not test
+        run: cmake --build build

.github/workflows/lint_and_format_check.yml

@@ -24,10 +24,10 @@ jobs:
   lint-and-format:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@9a9194f87191a7e9055e3e9b95b8cfb13023bb08 # v4.1.7
+      - uses: actions/checkout@ff7abcd0c3c05ccf6adc123a8cd1fd4fb30fb493 # v4.1.7
 
       - name: Run clang-format
-        uses: jidicula/clang-format-action@c74383674bf5f7c69f60ce562019c1c94bc1421a # v4.13.0
+        uses: jidicula/clang-format-action@4726374d1aa3c6aecf132e5197e498979588ebc8 # v4.15.0
         with:
           clang-format-version: '17'
 

.github/workflows/msys2-clang.yml

@@ -23,7 +23,7 @@ jobs:
       CMAKE_GENERATOR: Ninja
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v5
       - uses: msys2/setup-msys2@v2
         with:
           update: true

.github/workflows/msys2.yml

@@ -29,7 +29,7 @@ jobs:
       CMAKE_GENERATOR: Ninja
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v5
       - uses: msys2/setup-msys2@v2
         with:
           update: true

.github/workflows/on-release.yml

@@ -16,7 +16,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v5
       
       - name: Amalgamate fast_float.h
         run: |

.github/workflows/risc.yml

@@ -0,0 +1,23 @@
+name: Ubuntu RISC-V rvv VLEN=128 (clang 17)
+
+on: [push, pull_request]
+
+jobs:
+  build:
+    runs-on: ubuntu-24.04
+    steps:
+    - uses: actions/checkout@v5
+    - name: Install packages
+      run: |
+        sudo apt-get update -q -y
+        sudo apt-get install -y cmake make g++-riscv64-linux-gnu qemu-user-static clang-17
+    - name: Build
+      run: |
+        CXX=clang++-17 CXXFLAGS="--target=riscv64-linux-gnu -march=rv64gcv" \
+        cmake --toolchain=cmake/toolchains-ci/riscv64-linux-gnu.cmake -DCMAKE_BUILD_TYPE=Release -B build
+        cmake --build build/ -j$(nproc)
+    - name: Test VLEN=128
+      run: |
+        export QEMU_LD_PREFIX="/usr/riscv64-linux-gnu"
+        export QEMU_CPU="rv64,v=on,vlen=128,rvv_ta_all_1s=on,rvv_ma_all_1s=on"
+        ctest --timeout 1800 --output-on-failure --test-dir build -j $(nproc)

.github/workflows/s390x.yml

@@ -12,8 +12,8 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
-      - uses: uraimo/run-on-arch-action@v2
+      - uses: actions/checkout@v5
+      - uses: uraimo/run-on-arch-action@v3
         name: Test
         id: runcmd
         with:

.github/workflows/ubuntu20-fastmath.yml

@@ -1,16 +0,0 @@
-name: Ubuntu 20.04 CI (GCC 9, fast-math)
-
-on: [push, pull_request]
-
-jobs:
-  ubuntu-build:
-    runs-on: ubuntu-20.04
-    steps:
-      - uses: actions/checkout@v4
-      - name: Use cmake
-        run: |
-          mkdir build &&
-          cd build &&
-          cmake -DCMAKE_CXX_FLAGS="-ffast-math" -DFASTFLOAT_TEST=ON ..  &&
-          cmake --build .   &&
-          ctest --output-on-failure

.github/workflows/ubuntu20.yml

@@ -1,21 +0,0 @@
-name: Ubuntu 20.04 CI (GCC 9)
-
-on: [push, pull_request]
-
-jobs:
-  ubuntu-build:
-    runs-on: ubuntu-20.04
-    steps:
-      - uses: actions/checkout@v4
-      - name: Use cmake
-        run: |
-          mkdir build &&
-          cd build &&
-          cmake  ${{matrix.cxx}} ${{matrix.arch}} -DFASTFLOAT_TEST=ON -DCMAKE_INSTALL_PREFIX:PATH=destination ..  &&
-          cmake --build .   &&
-          ctest --output-on-failure  &&
-          cmake --install . &&
-          cd ../tests/installation_tests/find &&
-          mkdir build && cd build && cmake -DCMAKE_INSTALL_PREFIX:PATH=../../../build/destination .. &&  cmake --build . &&
-          cd ../../issue72_installation  &&
-          mkdir build && cd build && cmake -DCMAKE_INSTALL_PREFIX:PATH=../../../build/destination .. &&  cmake --build .

.github/workflows/ubuntu22-clang.yml

@@ -6,7 +6,7 @@ jobs:
   ubuntu-build:
     runs-on: ubuntu-22.04
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v5
       - name: Install clang++-14
         run: sudo apt-get install -y clang++-14
       - name: Use cmake

.github/workflows/ubuntu22-gcc12.yml

@@ -6,7 +6,7 @@ jobs:
   ubuntu-build:
     runs-on: ubuntu-22.04
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v5
       - name: Use cmake
         run: |
           mkdir build &&

.github/workflows/ubuntu22-sanitize.yml

@@ -6,7 +6,7 @@ jobs:
   ubuntu-build:
     runs-on: ubuntu-22.04
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v5
       - name: Use cmake
         run: |
           mkdir build &&

.github/workflows/ubuntu22.yml

@@ -6,7 +6,7 @@ jobs:
   ubuntu-build:
     runs-on: ubuntu-22.04
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v5
       - name: Use cmake
         run: |
           mkdir build &&

.github/workflows/ubuntu24-cxx20.yml

@@ -1,14 +1,14 @@
-name: Ubuntu 20.04 CI (C++20)
+name: Ubuntu 24.04 CI
 
 on: [push, pull_request]
 
 jobs:
   ubuntu-build:
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-24.04
     strategy:
       fail-fast: false
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v5
       - name: Use cmake
         run: |
           mkdir build &&

.github/workflows/ubuntu24.yml

@@ -6,18 +6,24 @@ jobs:
   ubuntu-build:
     runs-on: ubuntu-24.04
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v5
       - name: Use cmake
         run: |
-          mkdir build &&
-          cd build &&
-          CXXFLAGS=-Werror cmake -DFASTFLOAT_TEST=ON  ..  &&
-          cmake --build .   &&
-          ctest --output-on-failure
+          set -xe
+          cmake -B build \
+             -DFASTFLOAT_TEST=ON \
+             -DFASTFLOAT_BENCHMARKS=ON \
+             -DCMAKE_CXX_FLAGS=' -Werror -Wundef '
+          cmake --build build --parallel
+          ( cd build ; ctest --output-on-failure )
       - name: Use cmake CXX23
         run: |
-          mkdir build20 &&
-          cd build20 &&
-          CXXFLAGS=-Werror cmake -DFASTFLOAT_CONSTEXPR_TESTS=ON -DFASTFLOAT_FIXEDWIDTH_TESTS=ON -DFASTFLOAT_CXX_STANDARD=23 -DFASTFLOAT_TEST=ON  ..  &&
-          cmake --build .   &&
-          ctest --output-on-failure
+          set -xe
+          cmake -B build20 \
+             -DFASTFLOAT_TEST=ON \
+             -DFASTFLOAT_CONSTEXPR_TESTS=ON \
+             -DFASTFLOAT_FIXEDWIDTH_TESTS=ON \
+             -DFASTFLOAT_CXX_STANDARD=23 \
+             -DCMAKE_CXX_FLAGS=' -Werror -Wundef '
+          cmake --build build20 --parallel
+          ( cd build20 ; ctest --output-on-failure )

.github/workflows/vs17-arm-ci.yml

@@ -10,13 +10,11 @@ jobs:
       fail-fast: false
       matrix:
         include:
-          - {gen: Visual Studio 17 2022, arch: ARM, cfg: Release}
-          - {gen: Visual Studio 17 2022, arch: ARM, cfg: Debug}
           - {gen: Visual Studio 17 2022, arch: ARM64, cfg: Release}
           - {gen: Visual Studio 17 2022, arch: ARM64, cfg: Debug}
     steps:
       - name: checkout
-        uses: actions/checkout@v4
+        uses: actions/checkout@v5
       - name: configure
         run: |
           cmake -S . -B build -G "${{matrix.gen}}" -A ${{matrix.arch}} -DCMAKE_CROSSCOMPILING=1 -DFASTFLOAT_TEST=ON

.github/workflows/vs17-ci.yml

@@ -16,10 +16,10 @@ jobs:
           - {gen: Visual Studio 17 2022, arch: x64, cfg: Debug}
     steps:
       - name: checkout
-        uses: actions/checkout@v4
+        uses: actions/checkout@v5
       - name: configure
         run: |
-          cmake -S . -B build -G "${{matrix.gen}}" -A ${{matrix.arch}} -DFASTFLOAT_TEST=ON -DCMAKE_INSTALL_PREFIX:PATH=destination
+          cmake -S . -B build -G "${{matrix.gen}}" -A ${{matrix.arch}} -DFASTFLOAT_BENCHMARKS=ON  -DFASTFLOAT_TEST=ON -DCMAKE_INSTALL_PREFIX:PATH=destination
       - name: build
         run: |
           cmake --build build --verbose --config ${{matrix.cfg}} --parallel

.github/workflows/vs17-clang-ci.yml

@@ -16,10 +16,10 @@ jobs:
           - {gen: Visual Studio 17 2022, arch: x64, cfg: Debug}
     steps:
       - name: checkout
-        uses: actions/checkout@v4
+        uses: actions/checkout@v5
       - name: Configure
         run: |
-          cmake -S . -B build -G "${{matrix.gen}}" -A ${{matrix.arch}} -T ClangCL -DFASTFLOAT_TEST=ON
+          cmake -S . -B build -G "${{matrix.gen}}" -A ${{matrix.arch}} -DFASTFLOAT_BENCHMARKS=ON -T ClangCL -DFASTFLOAT_TEST=ON
       - name: Build
         run: cmake --build build --config ${{matrix.cfg}} --parallel --verbose
       - name: Run basic tests

.github/workflows/vs17-cxx20.yml

@@ -16,7 +16,7 @@ jobs:
           - {gen: Visual Studio 17 2022, arch: x64, cfg: Debug}
     steps:
       - name: checkout
-        uses: actions/checkout@v4
+        uses: actions/checkout@v5
       - name: configure
         run: >-
           cmake -S . -B build -G "${{matrix.gen}}" -A ${{matrix.arch}}

.gitignore

@@ -2,6 +2,7 @@ build/*
 Testing/*
 .cache/
 compile_commands.json
+bazel-*
 
 # Visual studio
 .vs/

BUILD.bazel

@@ -0,0 +1,6 @@
+cc_library(
+    name = "fast_float",
+    hdrs = glob(["include/fast_float/*.h"]),
+    strip_include_prefix = "include",
+    visibility = ["//visibility:public"],
+)

CMakeLists.txt

@@ -1,9 +1,11 @@
-cmake_minimum_required(VERSION 3.9)
+cmake_minimum_required(VERSION 3.14)
 
-project(fast_float VERSION 6.1.5 LANGUAGES CXX)
+
+project(fast_float VERSION 8.1.0 LANGUAGES CXX)
 set(FASTFLOAT_CXX_STANDARD 11 CACHE STRING "the C++ standard to use for fastfloat")
 set(CMAKE_CXX_STANDARD ${FASTFLOAT_CXX_STANDARD})
 option(FASTFLOAT_TEST "Enable tests" OFF)
+
 if(FASTFLOAT_TEST)
   enable_testing()
   add_subdirectory(tests)
@@ -29,6 +31,16 @@ if(FASTFLOAT_INSTALL)
 endif()
 
 add_library(fast_float INTERFACE)
+
+
+option(FASTFLOAT_BENCHMARKS "Enable benchmarks" OFF)
+if(FASTFLOAT_BENCHMARKS)
+  add_subdirectory(benchmarks)
+else(FASTFLOAT_BENCHMARKS)
+  message(STATUS "Benchmarks are disabled. Set FASTFLOAT_BENCHMARKS to ON to build benchmarks (assumes C++17).")
+endif(FASTFLOAT_BENCHMARKS)
+
+
 add_library(FastFloat::fast_float ALIAS fast_float)
 target_include_directories(
   fast_float
@@ -44,11 +56,15 @@ if(FASTFLOAT_SANITIZE)
     target_link_libraries(fast_float INTERFACE -fuse-ld=gold)
   endif()
 endif()
-if(MSVC_VERSION GREATER 1910)
+
+include(CheckCXXCompilerFlag)
+unset(FASTFLOAT_COMPILER_SUPPORTS_PERMISSIVE)
+CHECK_CXX_COMPILER_FLAG(/permissive- FASTFLOAT_COMPILER_SUPPORTS_PERMISSIVE)
+
+if(FASTFLOAT_COMPILER_SUPPORTS_PERMISSIVE)
   target_compile_options(fast_float INTERFACE /permissive-)
 endif()
 
-
 if(FASTFLOAT_INSTALL)
   include(CMakePackageConfigHelpers)
 

CONTRIBUTORS

@@ -8,3 +8,4 @@ Lénárd Szolnoki
 Jan Pharago
 Maya Warrier
 Taha Khokhar
+Anders Dalvander

MODULE.bazel

@@ -0,0 +1,9 @@
+"""fast_float number parsing library: 4x faster than strtod"""
+
+module(
+    name = "fast_float",
+    version = "6.1.6",
+    compatibility_level = 6,
+)
+
+bazel_dep(name = "doctest", version = "2.4.11", dev_dependency = True)

README.md

@@ -1,163 +1,212 @@
 
 ## fast_float number parsing library: 4x faster than strtod
-[![Fuzzing Status](https://oss-fuzz-build-logs.storage.googleapis.com/badges/fast_float.svg)](https://bugs.chromium.org/p/oss-fuzz/issues/list?sort=-opened&can=1&q=proj:fast_float)
+
 [![Ubuntu 22.04 CI (GCC 11)](https://github.com/fastfloat/fast_float/actions/workflows/ubuntu22.yml/badge.svg)](https://github.com/fastfloat/fast_float/actions/workflows/ubuntu22.yml)
 
-The fast_float library provides fast header-only implementations for the C++ from_chars
-functions for `float` and `double` types as well as integer types.  These functions convert ASCII strings representing decimal values (e.g., `1.3e10`) into binary types. We provide exact rounding (including
-round to even). In our experience, these `fast_float` functions many times faster than comparable number-parsing functions from existing C++ standard libraries.
+The fast_float library provides fast header-only implementations for the C++
+from_chars functions for `float` and `double` types as well as integer types.
+These functions convert ASCII strings representing decimal values (e.g.,
+`1.3e10`) into binary types. We provide exact rounding (including round to
+even). In our experience, these `fast_float` functions many times faster than
+comparable number-parsing functions from existing C++ standard libraries.
 
-Specifically, `fast_float` provides the following two functions to parse floating-point numbers with a C++17-like syntax (the library itself only requires C++11):
+Specifically, `fast_float` provides the following two functions to parse
+floating-point numbers with a C++17-like syntax (the library itself only
+requires C++11):
 
 ```C++
-from_chars_result from_chars(const char* first, const char* last, float& value, ...);
-from_chars_result from_chars(const char* first, const char* last, double& value, ...);
+from_chars_result from_chars(char const *first, char const *last, float &value, ...);
+from_chars_result from_chars(char const *first, char const *last, double &value, ...);
 ```
 
 You can also parse integer types:
 
-
-
+```C++
+from_chars_result from_chars(char const *first, char const *last, int &value, ...);
+from_chars_result from_chars(char const *first, char const *last, unsigned &value, ...);
+```
 
 The return type (`from_chars_result`) is defined as the struct:
+
 ```C++
 struct from_chars_result {
-    const char* ptr;
-    std::errc ec;
+  char const *ptr;
+  std::errc ec;
 };
 ```
 
-It parses the character sequence [first,last) for a number. It parses floating-point numbers expecting
-a locale-independent format equivalent to the C++17 from_chars function.
-The resulting floating-point value is the closest floating-point values (using either float or double),
-using the "round to even" convention for values that would otherwise fall right in-between two values.
-That is, we provide exact parsing according to the IEEE standard.
+It parses the character sequence `[first, last)` for a number. It parses
+floating-point numbers expecting a locale-independent format equivalent to the
+C++17 from_chars function. The resulting floating-point value is the closest
+floating-point values (using either `float` or `double`), using the "round to
+even" convention for values that would otherwise fall right in-between two
+values. That is, we provide exact parsing according to the IEEE standard.
 
+Given a successful parse, the pointer (`ptr`) in the returned value is set to
+point right after the parsed number, and the `value` referenced is set to the
+parsed value. In case of error, the returned `ec` contains a representative
+error, otherwise the default (`std::errc()`) value is stored.
 
-Given a successful parse, the pointer (`ptr`) in the returned value is set to point right after the
-parsed number, and the `value` referenced is set to the parsed value. In case of error, the returned
-`ec` contains a representative error, otherwise the default (`std::errc()`) value is stored.
-
-The implementation does not throw and does not allocate memory (e.g., with `new` or `malloc`).
+The implementation does not throw and does not allocate memory (e.g., with `new`
+or `malloc`).
 
 It will parse infinity and nan values.
 
 Example:
 
-``` C++
+```C++
 #include "fast_float/fast_float.h"
 #include <iostream>
+#include <string>
 
 int main() {
-    const std::string input =  "3.1416 xyz ";
-    double result;
-    auto answer = fast_float::from_chars(input.data(), input.data()+input.size(), result);
-    if(answer.ec != std::errc()) { std::cerr << "parsing failure\n"; return EXIT_FAILURE; }
+  std::string input = "3.1416 xyz ";
+  double result;
+  auto answer = fast_float::from_chars(input.data(), input.data() + input.size(), result);
+  if (answer.ec != std::errc()) { std::cerr << "parsing failure\n"; return EXIT_FAILURE; }
+  std::cout << "parsed the number " << result << std::endl;
+  return EXIT_SUCCESS;
+}
+```
+
+Though the C++17 standard has you do a comparison with `std::errc()` to check whether the conversion worked, you can avoid it by casting the result to a `bool` like so:
+
+```cpp
+#include "fast_float/fast_float.h"
+#include <iostream>
+#include <string>
+
+int main() {
+  std::string input = "3.1416 xyz ";
+  double result;
+  if(auto answer = fast_float::from_chars(input.data(), input.data() + input.size(), result)) {
     std::cout << "parsed the number " << result << std::endl;
     return EXIT_SUCCESS;
+  }
+  std::cerr << "failed to parse " << result << std::endl;
+  return EXIT_FAILURE;
 }
 ```
 
 You can parse delimited numbers:
+
 ```C++
-  const std::string input =   "234532.3426362,7869234.9823,324562.645";
+  std::string input = "234532.3426362,7869234.9823,324562.645";
   double result;
-  auto answer = fast_float::from_chars(input.data(), input.data()+input.size(), result);
-  if(answer.ec != std::errc()) {
+  auto answer = fast_float::from_chars(input.data(), input.data() + input.size(), result);
+  if (answer.ec != std::errc()) {
     // check error
   }
   // we have result == 234532.3426362.
-  if(answer.ptr[0] != ',') {
+  if (answer.ptr[0] != ',') {
     // unexpected delimiter
   }
-  answer = fast_float::from_chars(answer.ptr + 1, input.data()+input.size(), result);
-  if(answer.ec != std::errc()) {
+  answer = fast_float::from_chars(answer.ptr + 1, input.data() + input.size(), result);
+  if (answer.ec != std::errc()) {
     // check error
   }
   // we have result == 7869234.9823.
-  if(answer.ptr[0] != ',') {
+  if (answer.ptr[0] != ',') {
     // unexpected delimiter
   }
-  answer = fast_float::from_chars(answer.ptr + 1, input.data()+input.size(), result);
-  if(answer.ec != std::errc()) {
+  answer = fast_float::from_chars(answer.ptr + 1, input.data() + input.size(), result);
+  if (answer.ec != std::errc()) {
     // check error
   }
   // we have result == 324562.645.
 ```
 
+Like the C++17 standard, the `fast_float::from_chars` functions take an optional
+last argument of the type `fast_float::chars_format`. It is a bitset value: we
+check whether `fmt & fast_float::chars_format::fixed` and `fmt &
+fast_float::chars_format::scientific` are set to determine whether we allow the
+fixed point and scientific notation respectively. The default is
+`fast_float::chars_format::general` which allows both `fixed` and `scientific`.
 
+The library seeks to follow the C++17 (see
+[28.2.3.(6.1)](https://eel.is/c++draft/charconv.from.chars#6.1)) specification.
 
-Like the C++17 standard, the `fast_float::from_chars` functions take an optional last argument of
-the type `fast_float::chars_format`. It is a bitset value: we check whether
-`fmt & fast_float::chars_format::fixed` and `fmt & fast_float::chars_format::scientific` are set
-to determine whether we allow the fixed point and scientific notation respectively.
-The default is  `fast_float::chars_format::general` which allows both `fixed` and `scientific`.
-
-The library seeks to follow the C++17 (see [20.19.3](http://eel.is/c++draft/charconv.from.chars).(7.1))  specification.
-* The `from_chars` function does not skip leading white-space characters.
-* [A leading `+` sign](https://en.cppreference.com/w/cpp/utility/from_chars) is forbidden.
-* It is generally impossible to represent a decimal value exactly as binary floating-point number (`float` and `double` types). We seek the nearest value. We round to an even mantissa when we are in-between two binary floating-point numbers.
+* The `from_chars` function does not skip leading white-space characters (unless
+  `fast_float::chars_format::skip_white_space` is set).
+* [A leading `+` sign](https://en.cppreference.com/w/cpp/utility/from_chars) is
+  forbidden (unless `fast_float::chars_format::allow_leading_plus` is set).
+* It is generally impossible to represent a decimal value exactly as binary
+  floating-point number (`float` and `double` types). We seek the nearest value.
+  We round to an even mantissa when we are in-between two binary floating-point
+  numbers.
 
 Furthermore, we have the following restrictions:
-* We only support `float` and `double` types at this time.
+
+* We support `float` and `double`, but not `long double`. We also support
+  fixed-width floating-point types such as `std::float64_t`, `std::float32_t`,
+  `std::float16_t`, and `std::bfloat16_t`.
 * We only support the decimal format: we do not support hexadecimal strings.
-* For values that are either very large or very small (e.g., `1e9999`), we represent it using the infinity or negative infinity value and the returned `ec` is set to `std::errc::result_out_of_range`.
+* For values that are either very large or very small (e.g., `1e9999`), we
+  represent it using the infinity or negative infinity value and the returned
+  `ec` is set to `std::errc::result_out_of_range`.
 
-We support Visual Studio, macOS, Linux, freeBSD. We support big and little endian. We support 32-bit and 64-bit systems.
-
-We assume that the rounding mode is set to nearest (`std::fegetround() == FE_TONEAREST`).
+We support Visual Studio, macOS, Linux, freeBSD. We support big and little
+endian. We support 32-bit and 64-bit systems.
 
+We assume that the rounding mode is set to nearest (`std::fegetround() ==
+FE_TONEAREST`).
 
 ## Integer types
 
-You can also parse integer types using different bases (e.g., 2, 10, 16). The following code will
-print the number 22250738585072012 three times:
-
+You can also parse integer types using different bases (e.g., 2, 10, 16). The
+following code will print the number 22250738585072012 three times:
 
 ```C++
+#include "fast_float/fast_float.h"
+#include <iostream>
+
+int main() {
   uint64_t i;
-  const char str[] = "22250738585072012";
-  auto answer = fast_float::from_chars(str, str + strlen(str), i);
+  std::string str = "22250738585072012";
+  auto answer = fast_float::from_chars(str.data(), str.data() + str.size(), i);
   if (answer.ec != std::errc()) {
     std::cerr << "parsing failure\n";
     return EXIT_FAILURE;
   }
-  std::cout << "parsed the number "<< i << std::endl;
+  std::cout << "parsed the number " << i << std::endl;
 
-  const char binstr[] = "1001111000011001110110111001001010110100111000110001100";
+  std::string binstr = "1001111000011001110110111001001010110100111000110001100";
 
-  answer = fast_float::from_chars(binstr, binstr + strlen(binstr), i, 2);
+  answer = fast_float::from_chars(binstr.data(), binstr.data() + binstr.size(), i, 2);
   if (answer.ec != std::errc()) {
     std::cerr << "parsing failure\n";
     return EXIT_FAILURE;
   }
-  std::cout << "parsed the number "<< i << std::endl;
+  std::cout << "parsed the number " << i << std::endl;
 
+  std::string hexstr = "4f0cedc95a718c";
 
-  const char hexstr[] = "4f0cedc95a718c";
-
-  answer = fast_float::from_chars(hexstr, hexstr + strlen(hexstr), i, 16);
+  answer = fast_float::from_chars(hexstr.data(), hexstr.data() + hexstr.size(), i, 16);
   if (answer.ec != std::errc()) {
     std::cerr << "parsing failure\n";
     return EXIT_FAILURE;
   }
-  std::cout << "parsed the number "<< i << std::endl;
+  std::cout << "parsed the number " << i << std::endl;
+  return EXIT_SUCCESS;
+}
 ```
 
 ## Behavior of result_out_of_range
 
-When parsing floating-point values, the numbers can sometimes be too small (e.g., `1e-1000`) or
-too large (e.g., `1e1000`). The C language established the precedent that these small values are out of range.
-In such cases, it is customary to parse small values to zero and large
-values to infinity. That is the behaviour of the C language (e.g., `stdtod`). That is the behaviour followed by the fast_float library.
-
-
+When parsing floating-point values, the numbers can sometimes be too small
+(e.g., `1e-1000`) or too large (e.g., `1e1000`). The C language established the
+precedent that these small values are out of range. In such cases, it is
+customary to parse small values to zero and large values to infinity. That is
+the behaviour of the C language (e.g., `stdtod`). That is the behaviour followed
+by the fast_float library.
 
 Specifically, we follow Jonathan Wakely's interpretation of the standard:
 
-> In any case, the resulting value is one of at most two floating-point values closest to the value of the string matching the pattern.
+> In any case, the resulting value is one of at most two floating-point values
+> closest to the value of the string matching the pattern.
 
-It is also the approach taken by the [Microsoft C++ library](https://github.com/microsoft/STL/blob/62205ab155d093e71dd9588a78f02c5396c3c14b/tests/std/tests/P0067R5_charconv/test.cpp#L943-L946).
+It is also the approach taken by the [Microsoft C++
+library](https://github.com/microsoft/STL/blob/62205ab155d093e71dd9588a78f02c5396c3c14b/tests/std/tests/P0067R5_charconv/test.cpp#L943-L946).
 
 Hence, we have the following examples:
 
@@ -170,7 +219,6 @@ Hence, we have the following examples:
   // result == 0
 ```
 
-
 ```cpp
   double result = -1;
   std::string str = "3e1000";
@@ -180,26 +228,26 @@ Hence, we have the following examples:
   // result == std::numeric_limits<double>::infinity()
 ```
 
-Users who wish for the value to be left unmodified given `std::errc::result_out_of_range` may do so by adding two lines of code:
+Users who wish for the value to be left unmodified given
+`std::errc::result_out_of_range` may do so by adding two lines of code:
 
 ```cpp
   double old_result = result; // make copy
   auto r = fast_float::from_chars(start, end, result);
-  if(r.ec == std::errc::result_out_of_range) { result = old_result; }
+  if (r.ec == std::errc::result_out_of_range) { result = old_result; }
 ```
 
-
 ## C++20: compile-time evaluation (constexpr)
 
-In C++20, you may use `fast_float::from_chars` to parse strings
-at compile-time, as in the following example:
+In C++20, you may use `fast_float::from_chars` to parse strings at compile-time,
+as in the following example:
 
 ```C++
 // consteval forces compile-time evaluation of the function in C++20.
 consteval double parse(std::string_view input) {
   double result;
-  auto answer = fast_float::from_chars(input.data(), input.data()+input.size(), result);
-  if(answer.ec != std::errc()) { return -1.0; }
+  auto answer = fast_float::from_chars(input.data(), input.data() + input.size(), result);
+  if (answer.ec != std::errc()) { return -1.0; }
   return result;
 }
 
@@ -212,108 +260,107 @@ constexpr double constexptest() {
 
 ## C++23: Fixed width floating-point types
 
-The library also supports fixed-width floating-point types such as `std::float32_t` and `std::float64_t`. E.g., you can write:
+The library also supports fixed-width floating-point types such as
+`std::float64_t`, `std::float32_t`, `std::float16_t`, and `std::bfloat16_t`.
+E.g., you can write:
 
 ```C++
 std::float32_t result;
 auto answer = fast_float::from_chars(f.data(), f.data() + f.size(), result);
-``````
-
+```
 
 ## Non-ASCII Inputs
 
-We also support UTF-16 and UTF-32 inputs, as well as ASCII/UTF-8, as in the following example:
+We also support UTF-16 and UTF-32 inputs, as well as ASCII/UTF-8, as in the
+following example:
 
-``` C++
+```C++
 #include "fast_float/fast_float.h"
 #include <iostream>
 
 int main() {
-    const std::u16string input =  u"3.1416 xyz ";
-    double result;
-    auto answer = fast_float::from_chars(input.data(), input.data()+input.size(), result);
-    if(answer.ec != std::errc()) { std::cerr << "parsing failure\n"; return EXIT_FAILURE; }
-    std::cout << "parsed the number " << result << std::endl;
-    return EXIT_SUCCESS;
+  std::u16string input = u"3.1416 xyz ";
+  double result;
+  auto answer = fast_float::from_chars(input.data(), input.data() + input.size(), result);
+  if (answer.ec != std::errc()) { std::cerr << "parsing failure\n"; return EXIT_FAILURE; }
+  std::cout << "parsed the number " << result << std::endl;
+  return EXIT_SUCCESS;
 }
 ```
 
-## Advanced options:  using commas as decimal separator, JSON and Fortran
-
+## Advanced options: using commas as decimal separator, JSON and Fortran
 
 The C++ standard stipulate that `from_chars` has to be locale-independent. In
-particular, the decimal separator has to be the period (`.`). However,
-some users still want to use the `fast_float` library with in a locale-dependent
-manner. Using a separate function called `from_chars_advanced`, we allow the users
-to pass a `parse_options` instance which contains a custom decimal separator (e.g.,
-the comma). You may use it as follows.
+particular, the decimal separator has to be the period (`.`). However, some
+users still want to use the `fast_float` library with in a locale-dependent
+manner. Using a separate function called `from_chars_advanced`, we allow the
+users to pass a `parse_options` instance which contains a custom decimal
+separator (e.g., the comma). You may use it as follows.
 
 ```C++
 #include "fast_float/fast_float.h"
 #include <iostream>
 
 int main() {
-    const std::string input =  "3,1416 xyz ";
-    double result;
-    fast_float::parse_options options{fast_float::chars_format::general, ','};
-    auto answer = fast_float::from_chars_advanced(input.data(), input.data()+input.size(), result, options);
-    if((answer.ec != std::errc()) || ((result != 3.1416))) { std::cerr << "parsing failure\n"; return EXIT_FAILURE; }
-    std::cout << "parsed the number " << result << std::endl;
-    return EXIT_SUCCESS;
+  std::string input = "3,1416 xyz ";
+  double result;
+  fast_float::parse_options options{fast_float::chars_format::general, ','};
+  auto answer = fast_float::from_chars_advanced(input.data(), input.data() + input.size(), result, options);
+  if ((answer.ec != std::errc()) || ((result != 3.1416))) { std::cerr << "parsing failure\n"; return EXIT_FAILURE; }
+  std::cout << "parsed the number " << result << std::endl;
+  return EXIT_SUCCESS;
 }
 ```
 
-You can also parse Fortran-like inputs:
+### You can also parse Fortran-like inputs
 
 ```C++
 #include "fast_float/fast_float.h"
 #include <iostream>
 
 int main() {
-    const std::string input =  "1d+4";
-    double result;
-    fast_float::parse_options options{ fast_float::chars_format::fortran };
-    auto answer = fast_float::from_chars_advanced(input.data(), input.data()+input.size(), result, options);
-    if((answer.ec != std::errc()) || ((result != 10000))) { std::cerr << "parsing failure\n"; return EXIT_FAILURE; }
-    std::cout << "parsed the number " << result << std::endl;
-    return EXIT_SUCCESS;
+  std::string input = "1d+4";
+  double result;
+  fast_float::parse_options options{fast_float::chars_format::fortran};
+  auto answer = fast_float::from_chars_advanced(input.data(), input.data() + input.size(), result, options);
+  if ((answer.ec != std::errc()) || ((result != 10000))) { std::cerr << "parsing failure\n"; return EXIT_FAILURE; }
+  std::cout << "parsed the number " << result << std::endl;
+  return EXIT_SUCCESS;
 }
 ```
 
-You may also enforce the JSON format ([RFC 8259](https://datatracker.ietf.org/doc/html/rfc8259#section-6)):
-
+### You may also enforce the JSON format ([RFC 8259](https://datatracker.ietf.org/doc/html/rfc8259#section-6))
 
 ```C++
 #include "fast_float/fast_float.h"
 #include <iostream>
 
 int main() {
-    const std::string input =  "+.1"; // not valid
-    double result;
-    fast_float::parse_options options{ fast_float::chars_format::json };
-    auto answer = fast_float::from_chars_advanced(input.data(), input.data()+input.size(), result, options);
-    if(answer.ec == std::errc()) { std::cerr << "should have failed\n"; return EXIT_FAILURE; }
-    return EXIT_SUCCESS;
+  std::string input = "+.1"; // not valid
+  double result;
+  fast_float::parse_options options{fast_float::chars_format::json};
+  auto answer = fast_float::from_chars_advanced(input.data(), input.data() + input.size(), result, options);
+  if (answer.ec == std::errc()) { std::cerr << "should have failed\n"; return EXIT_FAILURE; }
+  return EXIT_SUCCESS;
 }
 ```
 
 By default the JSON format does not allow `inf`:
 
 ```C++
-
 #include "fast_float/fast_float.h"
 #include <iostream>
 
 int main() {
-    const std::string input =  "inf"; // not valid in JSON
-    double result;
-    fast_float::parse_options options{ fast_float::chars_format::json };
-    auto answer = fast_float::from_chars_advanced(input.data(), input.data()+input.size(), result, options);
-    if(answer.ec == std::errc()) { std::cerr << "should have failed\n"; return EXIT_FAILURE; }
+  std::string input = "inf"; // not valid in JSON
+  double result;
+  fast_float::parse_options options{fast_float::chars_format::json};
+  auto answer = fast_float::from_chars_advanced(input.data(), input.data() + input.size(), result, options);
+  if (answer.ec == std::errc()) { std::cerr << "should have failed\n"; return EXIT_FAILURE; }
+  return EXIT_SUCCESS;
 }
 ```
 
-
 You can allow it with a non-standard `json_or_infnan` variant:
 
 ```C++
@@ -321,54 +368,135 @@ You can allow it with a non-standard `json_or_infnan` variant:
 #include <iostream>
 
 int main() {
-    const std::string input =  "inf"; // not valid in JSON but we allow it with json_or_infnan
-    double result;
-    fast_float::parse_options options{ fast_float::chars_format::json_or_infnan };
-    auto answer = fast_float::from_chars_advanced(input.data(), input.data()+input.size(), result, options);
-    if(answer.ec != std::errc() || (!std::isinf(result))) { std::cerr << "should have parsed infinity\n"; return EXIT_FAILURE; }
-    return EXIT_SUCCESS;
+  std::string input = "inf"; // not valid in JSON but we allow it with json_or_infnan
+  double result;
+  fast_float::parse_options options{fast_float::chars_format::json_or_infnan};
+  auto answer = fast_float::from_chars_advanced(input.data(), input.data() + input.size(), result, options);
+  if (answer.ec != std::errc() || (!std::isinf(result))) { std::cerr << "should have parsed infinity\n"; return EXIT_FAILURE; }
+  return EXIT_SUCCESS;
 }
-``````
+```
+
+## Multiplication of an integer by a power of 10
+An integer `W` can be multiplied by a power of ten `10^Q` and
+converted to `double` with correctly rounded value
+(in "round to nearest, tie to even" fashion) using
+`fast_float::integer_times_pow10()`, e.g.:
+```C++
+const uint64_t W = 12345678901234567;
+const int Q = 23;
+const double result = fast_float::integer_times_pow10(W, Q);
+std::cout.precision(17);
+std::cout << W << " * 10^" << Q << " = " << result << " ("
+  << (result == 12345678901234567e23 ? "==" : "!=") << "expected)\n";
+```
+outputs
+```
+12345678901234567 * 10^23 = 1.2345678901234567e+39 (==expected)
+```
+`fast_float::integer_times_pow10()` gives the same result as
+using `fast_float::from_chars()` when parsing the string `"WeQ"`
+(in this example `"12345678901234567e23"`),
+except `fast_float::integer_times_pow10()` does not report out-of-range errors, and
+underflows to zero or overflows to infinity when the resulting value is
+out of range.
+
+You can use template overloads to get the result converted to different
+supported floating-point types: `float`, `double`, etc.
+For example, to get result as `float` use
+`fast_float::integer_times_pow10<float>()` specialization:
+```C++
+const uint64_t W = 12345678;
+const int Q = 23;
+const float result = fast_float::integer_times_pow10<float>(W, Q);
+std::cout.precision(9);
+std::cout << "float: " << W << " * 10^" << Q << " = " << result << " ("
+          << (result == 12345678e23f ? "==" : "!=") << "expected)\n";
+```
+outputs
+```
+float: 12345678 * 10^23 = 1.23456782e+30 (==expected)
+```
+
+Overloads of `fast_float::integer_times_pow10()` are provided for
+signed and unsigned integer types: `int64_t`, `uint64_t`, etc.
+
 
 ## Users and Related Work
 
 The fast_float library is part of:
 
-- GCC (as of version 12): the `from_chars` function in GCC relies on fast_float.
-- [Chromium](https://github.com/Chromium/Chromium), the engine behind Google Chrome and Microsoft Edge,
-- [WebKit](https://github.com/WebKit/WebKit), the engine behind Safari (Apple's web browser)
-- [DuckDB](https://duckdb.org)
-- [Apache Arrow](https://github.com/apache/arrow/pull/8494) where it multiplied the number parsing speed by two or three times
-- [Google Jsonnet](https://github.com/google/jsonnet)
-- [ClickHouse](https://github.com/ClickHouse/ClickHouse)
+* GCC (as of version 12): the `from_chars` function in GCC relies on fast_float,
+* [Chromium](https://github.com/Chromium/Chromium), the engine behind Google
+  Chrome, Microsoft Edge, and Opera,
+* Boost JSON, MySQL, etc.
+* Blender
+* [WebKit](https://github.com/WebKit/WebKit), the engine behind Safari (Apple's
+  web browser),
+* [DuckDB](https://duckdb.org),
+* [Redis](https://github.com/redis/redis) and [Valkey](https://github.com/valkey-io/valkey),
+* [Apache Arrow](https://github.com/apache/arrow/pull/8494) where it multiplied
+  the number parsing speed by two or three times,
+* [Google Jsonnet](https://github.com/google/jsonnet),
+* [ClickHouse](https://github.com/ClickHouse/ClickHouse).
+
+The fastfloat algorithm is part of the [LLVM standard
+libraries](https://github.com/llvm/llvm-project/commit/87c016078ad72c46505461e4ff8bfa04819fe7ba).
+There is a [derived implementation part of
+AdaCore](https://github.com/AdaCore/VSS). The [SerenityOS operating
+system](https://github.com/SerenityOS/serenity/commit/53b7f5e6a11e663c83df8030c3171c5945cb75ec)
+has a derived implementation that is inherited by the [Ladybird
+Browser](https://github.com/LadybirdBrowser/ladybird).
+
+The fast_float library provides a performance similar to that of the
+[fast_double_parser](https://github.com/lemire/fast_double_parser) library but
+using an updated algorithm reworked from the ground up, and while offering an
+API more in line with the expectations of C++ programmers. The
+fast_double_parser library is part of the [Microsoft LightGBM machine-learning
+framework](https://github.com/microsoft/LightGBM).
 
 
-The fastfloat algorithm is part of the [LLVM standard libraries](https://github.com/llvm/llvm-project/commit/87c016078ad72c46505461e4ff8bfa04819fe7ba). There is a [derived implementation part of AdaCore](https://github.com/AdaCore/VSS).
 
-The fast_float library provides a performance similar to that of the [fast_double_parser](https://github.com/lemire/fast_double_parser) library but using an updated algorithm reworked from the ground up, and while offering an API more in line with the expectations of C++ programmers. The fast_double_parser library is part of the [Microsoft LightGBM machine-learning framework](https://github.com/microsoft/LightGBM).
+Packages
+------
+
+[![Packaging status](https://repology.org/badge/vertical-allrepos/fast-float.svg)](https://repology.org/project/fast-float/versions)
+
 
 ## References
 
-- Daniel Lemire, [Number Parsing at a Gigabyte per Second](https://arxiv.org/abs/2101.11408), Software: Practice and Experience 51 (8), 2021.
-- Noble Mushtak, Daniel Lemire, [Fast Number Parsing Without Fallback](https://arxiv.org/abs/2212.06644), Software: Practice and Experience 53 (7), 2023.
+* Daniel Lemire, [Number Parsing at a Gigabyte per
+  Second](https://arxiv.org/abs/2101.11408), Software: Practice and Experience
+  51 (8), 2021.
+* Noble Mushtak, Daniel Lemire, [Fast Number Parsing Without
+  Fallback](https://arxiv.org/abs/2212.06644), Software: Practice and Experience
+  53 (7), 2023.
 
 ## Other programming languages
 
-- [There is an R binding](https://github.com/eddelbuettel/rcppfastfloat) called `rcppfastfloat`.
-- [There is a Rust port of the fast_float library](https://github.com/aldanor/fast-float-rust/) called `fast-float-rust`.
-- [There is a Java port of the fast_float library](https://github.com/wrandelshofer/FastDoubleParser) called `FastDoubleParser`. It used for important systems such as [Jackson](https://github.com/FasterXML/jackson-core).
-- [There is a C# port of the fast_float library](https://github.com/CarlVerret/csFastFloat) called `csFastFloat`.
-
-
-
+* [There is an R binding](https://github.com/eddelbuettel/rcppfastfloat) called
+  `rcppfastfloat`.
+* [There is a Rust port of the fast_float
+  library](https://github.com/aldanor/fast-float-rust/) called
+  `fast-float-rust`.
+* [There is a Java port of the fast_float
+  library](https://github.com/wrandelshofer/FastDoubleParser) called
+  `FastDoubleParser`. It used for important systems such as
+  [Jackson](https://github.com/FasterXML/jackson-core).
+* [There is a C# port of the fast_float
+  library](https://github.com/CarlVerret/csFastFloat) called `csFastFloat`.
 
 ## How fast is it?
 
-It can parse random floating-point numbers at a speed of 1 GB/s on some systems. We find that it is often twice as fast as the best available competitor, and many times faster than many standard-library implementations.
+It can parse random floating-point numbers at a speed of 1 GB/s on some systems.
+We find that it is often twice as fast as the best available competitor, and
+many times faster than many standard-library implementations.
 
-<img src="http://lemire.me/blog/wp-content/uploads/2020/11/fastfloat_speed.png" width="400">
+<img src="https://lemire.me/blog/wp-content/uploads/2020/11/fastfloat_speed.png"
+width="400" alt="fast_float is many times faster than many standard-library
+implementations">
 
-```
+```bash
 $ ./build/benchmarks/benchmark
 # parsing random integers in the range [0,1)
 volume = 2.09808 MB
@@ -379,91 +507,128 @@ abseil                                  :   430.45 MB/s (+/- 2.2 %)    20.52 Mfl
 fastfloat                               :  1042.38 MB/s (+/- 9.9 %)    49.68 Mfloat/s
 ```
 
-See https://github.com/lemire/simple_fastfloat_benchmark for our benchmarking code.
-
+See the [Benchmarking](#benchmarking) section for instructions on how to run our benchmarks.
 
 ## Video
 
-[![Go Systems 2020](http://img.youtube.com/vi/AVXgvlMeIm4/0.jpg)](http://www.youtube.com/watch?v=AVXgvlMeIm4)<br />
+[![Go Systems 2020](https://img.youtube.com/vi/AVXgvlMeIm4/0.jpg)](https://www.youtube.com/watch?v=AVXgvlMeIm4)
 
 ## Using as a CMake dependency
 
-This library is header-only by design. The CMake file provides the `fast_float` target
-which is merely a pointer to the `include` directory.
+This library is header-only by design. The CMake file provides the `fast_float`
+target which is merely a pointer to the `include` directory.
 
-If you drop the `fast_float` repository in your CMake project, you should be able to use
-it in this manner:
+If you drop the `fast_float` repository in your CMake project, you should be
+able to use it in this manner:
 
 ```cmake
 add_subdirectory(fast_float)
 target_link_libraries(myprogram PUBLIC fast_float)
 ```
 
-Or you may want to retrieve the dependency automatically if you have a sufficiently recent version of CMake (3.11 or better at least):
+Or you may want to retrieve the dependency automatically if you have a
+sufficiently recent version of CMake (3.11 or better at least):
 
 ```cmake
 FetchContent_Declare(
   fast_float
-  GIT_REPOSITORY https://github.com/lemire/fast_float.git
-  GIT_TAG tags/v1.1.2
+  GIT_REPOSITORY https://github.com/fastfloat/fast_float.git
+  GIT_TAG tags/v8.1.0
   GIT_SHALLOW TRUE)
 
 FetchContent_MakeAvailable(fast_float)
 target_link_libraries(myprogram PUBLIC fast_float)
-
 ```
 
-You should change the `GIT_TAG` line so that you recover the version you wish to use.
+You should change the `GIT_TAG` line so that you recover the version you wish to
+use.
 
 You may also use [CPM](https://github.com/cpm-cmake/CPM.cmake), like so:
 
-```
+```cmake
 CPMAddPackage(
-    NAME fast_float
-    GITHUB_REPOSITORY "fastfloat/fast_float"
-    GIT_TAG v6.1.4)
+  NAME fast_float
+  GITHUB_REPOSITORY "fastfloat/fast_float"
+  GIT_TAG v8.1.0)
 ```
 
-
 ## Using as single header
 
 The script `script/amalgamate.py` may be used to generate a single header
-version of the library if so desired.
-Just run the script from the root directory of this repository.
-You can customize the license type and output file if desired as described in
-the command line help.
+version of the library if so desired. Just run the script from the root
+directory of this repository. You can customize the license type and output file
+if desired as described in the command line help.
 
 You may directly download automatically generated single-header files:
 
-https://github.com/fastfloat/fast_float/releases/download/v6.1.5/fast_float.h
+<https://github.com/fastfloat/fast_float/releases/download/v8.1.0/fast_float.h>
+
+## Benchmarking
+
+The project has its own benchmarks with realistic data inputs. Under Linux or macOS,
+you can use it as follows if your system supports C++17:
+
+```
+cmake -B build -D FASTFLOAT_BENCHMARKS=ON
+cmake --build build
+./build/benchmarks/realbenchmark
+```
+
+Importantly, by default, the benchmark is built in Release mode.
+
+The instructions are similar under Windows.
+
+Under Linux and macOS, it is recommended to run the benchmarks in a privileged manner to get access
+to hardware performance counters. You may be able to do so with the `sudo` command
+in some cases:
+
+```
+sudo ./build/benchmarks/realbenchmark
+```
+
+If you have a text file containing one number per line (`myfile.txt`), you can run a benchmark over it like so:
+```
+cmake -B build -D FASTFLOAT_BENCHMARKS=ON
+cmake --build build
+./build/benchmarks/realbenchmark myfile.txt
+```
+
 
 ## Packages
 
-- The fast_float library is part of the [Conan package manager](https://conan.io/center/recipes/fast_float).
-- It is part of the [brew package manager](https://formulae.brew.sh/formula/fast_float).
-- Some Linux distribution like Fedora include fast_float (e.g., as `fast_float-devel`).
-
-## RFC 7159
-
-If you need support for RFC 7159 (JSON standard), you may want to consider using the [fast_double_parser](https://github.com/lemire/fast_double_parser/) library instead.
+* The fast_float library is part of the [Conan package
+  manager](https://conan.io/center/recipes/fast_float).
+* It is part of the [brew package
+  manager](https://formulae.brew.sh/formula/fast_float).
+* fast_float is available on [xmake](https://xmake.io) repository.
+* Some Linux distribution like Fedora include fast_float (e.g., as
+  `fast_float-devel`).
 
 ## Credit
 
-Though this work is inspired by many different people, this work benefited especially from exchanges with
-Michael Eisel, who motivated the original research with his key insights, and with Nigel Tao who provided
-invaluable feedback. Rémy Oudompheng first implemented a fast path we use in the case of long digits.
+Though this work is inspired by many different people, this work benefited
+especially from exchanges with Michael Eisel, who motivated the original
+research with his key insights, and with Nigel Tao who provided invaluable
+feedback. Rémy Oudompheng first implemented a fast path we use in the case of
+long digits.
 
-The library includes code adapted from Google Wuffs (written by Nigel Tao) which was originally published
-under the Apache 2.0 license.
+The library includes code adapted from Google Wuffs (written by Nigel Tao) which
+was originally published under the Apache 2.0 license.
+
+## Stars
+
+
+[![Star History Chart](https://api.star-history.com/svg?repos=fastfloat/fast_float&type=Date)](https://www.star-history.com/#fastfloat/fast_float&Date)
 
 ## License
 
 <sup>
 Licensed under either of <a href="LICENSE-APACHE">Apache License, Version
-2.0</a> or <a href="LICENSE-MIT">MIT license</a> or <a href="LICENSE-BOOST">BOOST license</a> .
+2.0</a> or <a href="LICENSE-MIT">MIT license</a> or <a
+href="LICENSE-BOOST">BOOST license</a>.
 </sup>
 
-<br>
+<br/>
 
 <sub>
 Unless you explicitly state otherwise, any contribution intentionally submitted

benchmarks/CMakeLists.txt

@@ -0,0 +1,26 @@
+add_executable(realbenchmark benchmark.cpp)
+set_property(
+    TARGET realbenchmark
+    PROPERTY CXX_STANDARD 17)
+
+target_link_libraries(realbenchmark PUBLIC fast_float)
+include(ExternalProject)
+
+# Define the external project
+ExternalProject_Add(simple_fastfloat_benchmark
+    GIT_REPOSITORY https://github.com/lemire/simple_fastfloat_benchmark.git
+    GIT_TAG        master  # or specify a particular commit/tag/branch
+    SOURCE_DIR     ${CMAKE_BINARY_DIR}/simple_fastfloat_benchmark
+    BINARY_DIR     ${CMAKE_BINARY_DIR}/simple_fastfloat_benchmark-build
+    CONFIGURE_COMMAND ""
+    BUILD_COMMAND ""
+    INSTALL_COMMAND ""
+)
+set(DATA_DIR ${CMAKE_BINARY_DIR}/simple_fastfloat_benchmark/data)
+
+add_custom_target(CopyData ALL
+    COMMAND ${CMAKE_COMMAND} -E copy_directory ${DATA_DIR} ${CMAKE_CURRENT_BINARY_DIR}/data
+    DEPENDS simple_fastfloat_benchmark
+)
+add_dependencies(realbenchmark CopyData)
+target_compile_definitions(realbenchmark PUBLIC BENCHMARK_DATA_DIR="${CMAKE_CURRENT_BINARY_DIR}/data")

benchmarks/benchmark.cpp

@@ -0,0 +1,246 @@
+#if defined(__linux__) || (__APPLE__ && __aarch64__)
+#define USING_COUNTERS
+#endif
+#include "event_counter.h"
+#include <algorithm>
+#include "fast_float/fast_float.h"
+#include <chrono>
+#include <climits>
+#include <cmath>
+#include <cstdint>
+#include <cstdio>
+#include <cstdlib>
+#include <cstring>
+#include <ctype.h>
+#include <fstream>
+#include <iomanip>
+#include <iostream>
+#include <random>
+#include <sstream>
+#include <stdio.h>
+#include <string>
+#include <vector>
+#include <locale.h>
+
+template <typename CharT>
+double findmax_fastfloat64(std::vector<std::basic_string<CharT>> &s) {
+  double answer = 0;
+  double x = 0;
+  for (auto &st : s) {
+    auto [p, ec] = fast_float::from_chars(st.data(), st.data() + st.size(), x);
+    if (p == st.data()) {
+      throw std::runtime_error("bug in findmax_fastfloat");
+    }
+    answer = answer > x ? answer : x;
+  }
+  return answer;
+}
+
+template <typename CharT>
+double findmax_fastfloat32(std::vector<std::basic_string<CharT>> &s) {
+  float answer = 0;
+  float x = 0;
+  for (auto &st : s) {
+    auto [p, ec] = fast_float::from_chars(st.data(), st.data() + st.size(), x);
+    if (p == st.data()) {
+      throw std::runtime_error("bug in findmax_fastfloat");
+    }
+    answer = answer > x ? answer : x;
+  }
+  return answer;
+}
+
+event_collector collector{};
+
+#ifdef USING_COUNTERS
+template <class T, class CharT>
+std::vector<event_count>
+time_it_ns(std::vector<std::basic_string<CharT>> &lines, T const &function,
+           size_t repeat) {
+  std::vector<event_count> aggregate;
+  bool printed_bug = false;
+  for (size_t i = 0; i < repeat; i++) {
+    collector.start();
+    double ts = function(lines);
+    if (ts == 0 && !printed_bug) {
+      printf("bug\n");
+      printed_bug = true;
+    }
+    aggregate.push_back(collector.end());
+  }
+  return aggregate;
+}
+
+void pretty_print(double volume, size_t number_of_floats, std::string name,
+                  std::vector<event_count> events) {
+  double volumeMB = volume / (1024. * 1024.);
+  double average_ns{0};
+  double min_ns{DBL_MAX};
+  double cycles_min{DBL_MAX};
+  double instructions_min{DBL_MAX};
+  double cycles_avg{0};
+  double instructions_avg{0};
+  double branches_min{0};
+  double branches_avg{0};
+  double branch_misses_min{0};
+  double branch_misses_avg{0};
+  for (event_count e : events) {
+    double ns = e.elapsed_ns();
+    average_ns += ns;
+    min_ns = min_ns < ns ? min_ns : ns;
+
+    double cycles = e.cycles();
+    cycles_avg += cycles;
+    cycles_min = cycles_min < cycles ? cycles_min : cycles;
+
+    double instructions = e.instructions();
+    instructions_avg += instructions;
+    instructions_min =
+        instructions_min < instructions ? instructions_min : instructions;
+
+    double branches = e.branches();
+    branches_avg += branches;
+    branches_min = branches_min < branches ? branches_min : branches;
+
+    double branch_misses = e.missed_branches();
+    branch_misses_avg += branch_misses;
+    branch_misses_min =
+        branch_misses_min < branch_misses ? branch_misses_min : branch_misses;
+  }
+  cycles_avg /= events.size();
+  instructions_avg /= events.size();
+  average_ns /= events.size();
+  branches_avg /= events.size();
+  printf("%-40s: %8.2f MB/s (+/- %.1f %%) ", name.data(),
+         volumeMB * 1000000000 / min_ns,
+         (average_ns - min_ns) * 100.0 / average_ns);
+  printf("%8.2f Mfloat/s  ", number_of_floats * 1000 / min_ns);
+  if (instructions_min > 0) {
+    printf(" %8.2f i/B %8.2f i/f (+/- %.1f %%) ", instructions_min / volume,
+           instructions_min / number_of_floats,
+           (instructions_avg - instructions_min) * 100.0 / instructions_avg);
+
+    printf(" %8.2f c/B %8.2f c/f (+/- %.1f %%) ", cycles_min / volume,
+           cycles_min / number_of_floats,
+           (cycles_avg - cycles_min) * 100.0 / cycles_avg);
+    printf(" %8.2f i/c ", instructions_min / cycles_min);
+    printf(" %8.2f b/f ", branches_avg / number_of_floats);
+    printf(" %8.2f bm/f ", branch_misses_avg / number_of_floats);
+    printf(" %8.2f GHz ", cycles_min / min_ns);
+  }
+  printf("\n");
+}
+#else
+template <class T, class CharT>
+std::pair<double, double>
+time_it_ns(std::vector<std::basic_string<CharT>> &lines, T const &function,
+           size_t repeat) {
+  std::chrono::high_resolution_clock::time_point t1, t2;
+  double average = 0;
+  double min_value = DBL_MAX;
+  bool printed_bug = false;
+  for (size_t i = 0; i < repeat; i++) {
+    t1 = std::chrono::high_resolution_clock::now();
+    double ts = function(lines);
+    if (ts == 0 && !printed_bug) {
+      printf("bug\n");
+      printed_bug = true;
+    }
+    t2 = std::chrono::high_resolution_clock::now();
+    double dif =
+        std::chrono::duration_cast<std::chrono::nanoseconds>(t2 - t1).count();
+    average += dif;
+    min_value = min_value < dif ? min_value : dif;
+  }
+  average /= repeat;
+  return std::make_pair(min_value, average);
+}
+
+void pretty_print(double volume, size_t number_of_floats, std::string name,
+                  std::pair<double, double> result) {
+  double volumeMB = volume / (1024. * 1024.);
+  printf("%-40s: %8.2f MB/s (+/- %.1f %%) ", name.data(),
+         volumeMB * 1000000000 / result.first,
+         (result.second - result.first) * 100.0 / result.second);
+  printf("%8.2f Mfloat/s  ", number_of_floats * 1000 / result.first);
+  printf(" %8.2f ns/f \n", double(result.first) / number_of_floats);
+}
+#endif
+
+// this is okay, all chars are ASCII
+inline std::u16string widen(std::string line) {
+  std::u16string u16line;
+  u16line.resize(line.size());
+  for (size_t i = 0; i < line.size(); ++i) {
+    u16line[i] = char16_t(line[i]);
+  }
+  return u16line;
+}
+
+std::vector<std::u16string> widen(const std::vector<std::string> &lines) {
+  std::vector<std::u16string> u16lines;
+  u16lines.reserve(lines.size());
+  for (auto const &line : lines) {
+    u16lines.push_back(widen(line));
+  }
+  return u16lines;
+}
+
+void process(std::vector<std::string> &lines, size_t volume) {
+  size_t repeat = 1000;
+  double volumeMB = volume / (1024. * 1024.);
+  std::cout << "ASCII volume = " << volumeMB << " MB " << std::endl;
+  pretty_print(volume, lines.size(), "fastfloat (64)",
+               time_it_ns(lines, findmax_fastfloat64<char>, repeat));
+  pretty_print(volume, lines.size(), "fastfloat (32)",
+               time_it_ns(lines, findmax_fastfloat32<char>, repeat));
+
+  std::vector<std::u16string> lines16 = widen(lines);
+  volume = 2 * volume;
+  volumeMB = volume / (1024. * 1024.);
+  std::cout << "UTF-16 volume = " << volumeMB << " MB " << std::endl;
+  pretty_print(volume, lines.size(), "fastfloat (64)",
+               time_it_ns(lines16, findmax_fastfloat64<char16_t>, repeat));
+  pretty_print(volume, lines.size(), "fastfloat (32)",
+               time_it_ns(lines16, findmax_fastfloat32<char16_t>, repeat));
+}
+
+void fileload(std::string filename) {
+  std::ifstream inputfile(filename);
+  if (!inputfile) {
+    std::cerr << "can't open " << filename << std::endl;
+    return;
+  }
+  std::cout << "#### " << std::endl;
+  std::cout << "# reading " << filename << std::endl;
+  std::cout << "#### " << std::endl;
+  std::string line;
+  std::vector<std::string> lines;
+  lines.reserve(10000); // let us reserve plenty of memory.
+  size_t volume = 0;
+  while (getline(inputfile, line)) {
+    volume += line.size();
+    lines.push_back(line);
+  }
+  std::cout << "# read " << lines.size() << " lines " << std::endl;
+  process(lines, volume);
+}
+
+int main(int argc, char **argv) {
+  if (collector.has_events()) {
+    std::cout << "# Using hardware counters" << std::endl;
+  } else {
+#if defined(__linux__) || (__APPLE__ && __aarch64__)
+    std::cout << "# Hardware counters not available, try to run in privileged "
+                 "mode (e.g., sudo)."
+              << std::endl;
+#endif
+  }
+  if (argc > 1) {
+    fileload(argv[1]);
+    return EXIT_SUCCESS;
+  }
+  fileload(std::string(BENCHMARK_DATA_DIR) + "/canada.txt");
+  fileload(std::string(BENCHMARK_DATA_DIR) + "/mesh.txt");
+  return EXIT_SUCCESS;
+}

benchmarks/event_counter.h

@@ -0,0 +1,181 @@
+#ifndef __EVENT_COUNTER_H
+#define __EVENT_COUNTER_H
+
+#include <cctype>
+#ifndef _MSC_VER
+#include <dirent.h>
+#endif
+#include <cinttypes>
+
+#include <cstring>
+
+#include <chrono>
+#include <vector>
+
+#include "linux-perf-events.h"
+#ifdef __linux__
+#include <libgen.h>
+#endif
+
+#if (defined(__APPLE__) && __APPLE__) && (defined(__aarch64__) && __aarch64__)
+#include "apple_arm_events.h"
+#endif
+
+struct event_count {
+  std::chrono::duration<double> elapsed;
+  std::vector<unsigned long long> event_counts;
+
+  event_count() : elapsed(0), event_counts{0, 0, 0, 0, 0} {}
+
+  event_count(const std::chrono::duration<double> _elapsed,
+              const std::vector<unsigned long long> _event_counts)
+      : elapsed(_elapsed), event_counts(_event_counts) {}
+
+  event_count(const event_count &other)
+      : elapsed(other.elapsed), event_counts(other.event_counts) {}
+
+  // The types of counters (so we can read the getter more easily)
+  enum event_counter_types {
+    CPU_CYCLES = 0,
+    INSTRUCTIONS = 1,
+    BRANCHES = 2,
+    MISSED_BRANCHES = 3
+  };
+
+  double elapsed_sec() const {
+    return std::chrono::duration<double>(elapsed).count();
+  }
+
+  double elapsed_ns() const {
+    return std::chrono::duration<double, std::nano>(elapsed).count();
+  }
+
+  double cycles() const {
+    return static_cast<double>(event_counts[CPU_CYCLES]);
+  }
+
+  double instructions() const {
+    return static_cast<double>(event_counts[INSTRUCTIONS]);
+  }
+
+  double branches() const {
+    return static_cast<double>(event_counts[BRANCHES]);
+  }
+
+  double missed_branches() const {
+    return static_cast<double>(event_counts[MISSED_BRANCHES]);
+  }
+
+  event_count &operator=(const event_count &other) {
+    this->elapsed = other.elapsed;
+    this->event_counts = other.event_counts;
+    return *this;
+  }
+
+  event_count operator+(const event_count &other) const {
+    return event_count(elapsed + other.elapsed,
+                       {
+                           event_counts[0] + other.event_counts[0],
+                           event_counts[1] + other.event_counts[1],
+                           event_counts[2] + other.event_counts[2],
+                           event_counts[3] + other.event_counts[3],
+                           event_counts[4] + other.event_counts[4],
+                       });
+  }
+
+  void operator+=(const event_count &other) { *this = *this + other; }
+};
+
+struct event_aggregate {
+  bool has_events = false;
+  int iterations = 0;
+  event_count total{};
+  event_count best{};
+  event_count worst{};
+
+  event_aggregate() = default;
+
+  void operator<<(const event_count &other) {
+    if (iterations == 0 || other.elapsed < best.elapsed) {
+      best = other;
+    }
+    if (iterations == 0 || other.elapsed > worst.elapsed) {
+      worst = other;
+    }
+    iterations++;
+    total += other;
+  }
+
+  double elapsed_sec() const { return total.elapsed_sec() / iterations; }
+
+  double elapsed_ns() const { return total.elapsed_ns() / iterations; }
+
+  double cycles() const { return total.cycles() / iterations; }
+
+  double instructions() const { return total.instructions() / iterations; }
+
+  double branches() const { return total.branches() / iterations; }
+
+  double missed_branches() const {
+    return total.missed_branches() / iterations;
+  }
+};
+
+struct event_collector {
+  event_count count{};
+  std::chrono::time_point<std::chrono::steady_clock> start_clock{};
+
+#if defined(__linux__)
+  LinuxEvents<PERF_TYPE_HARDWARE> linux_events;
+
+  event_collector()
+      : linux_events(std::vector<int>{
+            PERF_COUNT_HW_CPU_CYCLES, PERF_COUNT_HW_INSTRUCTIONS,
+            PERF_COUNT_HW_BRANCH_INSTRUCTIONS, // Retired branch instructions
+            PERF_COUNT_HW_BRANCH_MISSES}) {}
+
+  bool has_events() { return linux_events.is_working(); }
+#elif __APPLE__ && __aarch64__
+  performance_counters diff;
+
+  event_collector() : diff(0) { setup_performance_counters(); }
+
+  bool has_events() { return setup_performance_counters(); }
+#else
+  event_collector() {}
+
+  bool has_events() { return false; }
+#endif
+
+  inline void start() {
+#if defined(__linux)
+    linux_events.start();
+#elif __APPLE__ && __aarch64__
+    if (has_events()) {
+      diff = get_counters();
+    }
+#endif
+    start_clock = std::chrono::steady_clock::now();
+  }
+
+  inline event_count &end() {
+    const auto end_clock = std::chrono::steady_clock::now();
+#if defined(__linux)
+    linux_events.end(count.event_counts);
+#elif __APPLE__ && __aarch64__
+    if (has_events()) {
+      performance_counters end = get_counters();
+      diff = end - diff;
+    }
+    count.event_counts[0] = diff.cycles;
+    count.event_counts[1] = diff.instructions;
+    count.event_counts[2] = diff.branches;
+    count.event_counts[3] = diff.missed_branches;
+    count.event_counts[4] = 0;
+#endif
+    count.elapsed = end_clock - start_clock;
+    return count;
+  }
+};
+
+#endif

benchmarks/linux-perf-events.h

@@ -0,0 +1,104 @@
+#pragma once
+#ifdef __linux__
+
+#include <asm/unistd.h>       // for __NR_perf_event_open
+#include <linux/perf_event.h> // for perf event constants
+#include <sys/ioctl.h>        // for ioctl
+#include <unistd.h>           // for syscall
+
+#include <cerrno>  // for errno
+#include <cstring> // for memset
+#include <stdexcept>
+
+#include <iostream>
+#include <vector>
+
+template <int TYPE = PERF_TYPE_HARDWARE> class LinuxEvents {
+  int fd;
+  bool working;
+  perf_event_attr attribs{};
+  size_t num_events{};
+  std::vector<uint64_t> temp_result_vec{};
+  std::vector<uint64_t> ids{};
+
+public:
+  explicit LinuxEvents(std::vector<int> config_vec) : fd(0), working(true) {
+    memset(&attribs, 0, sizeof(attribs));
+    attribs.type = TYPE;
+    attribs.size = sizeof(attribs);
+    attribs.disabled = 1;
+    attribs.exclude_kernel = 1;
+    attribs.exclude_hv = 1;
+
+    attribs.sample_period = 0;
+    attribs.read_format = PERF_FORMAT_GROUP | PERF_FORMAT_ID;
+    const int pid = 0;  // the current process
+    const int cpu = -1; // all CPUs
+    const unsigned long flags = 0;
+
+    int group = -1; // no group
+    num_events = config_vec.size();
+    ids.resize(config_vec.size());
+    uint32_t i = 0;
+    for (auto config : config_vec) {
+      attribs.config = config;
+      int _fd = static_cast<int>(
+          syscall(__NR_perf_event_open, &attribs, pid, cpu, group, flags));
+      if (_fd == -1) {
+        report_error("perf_event_open");
+      }
+      ioctl(_fd, PERF_EVENT_IOC_ID, &ids[i++]);
+      if (group == -1) {
+        group = _fd;
+        fd = _fd;
+      }
+    }
+
+    temp_result_vec.resize(num_events * 2 + 1);
+  }
+
+  ~LinuxEvents() {
+    if (fd != -1) {
+      close(fd);
+    }
+  }
+
+  inline void start() {
+    if (fd != -1) {
+      if (ioctl(fd, PERF_EVENT_IOC_RESET, PERF_IOC_FLAG_GROUP) == -1) {
+        report_error("ioctl(PERF_EVENT_IOC_RESET)");
+      }
+
+      if (ioctl(fd, PERF_EVENT_IOC_ENABLE, PERF_IOC_FLAG_GROUP) == -1) {
+        report_error("ioctl(PERF_EVENT_IOC_ENABLE)");
+      }
+    }
+  }
+
+  inline void end(std::vector<unsigned long long> &results) {
+    if (fd != -1) {
+      if (ioctl(fd, PERF_EVENT_IOC_DISABLE, PERF_IOC_FLAG_GROUP) == -1) {
+        report_error("ioctl(PERF_EVENT_IOC_DISABLE)");
+      }
+
+      if (read(fd, temp_result_vec.data(), temp_result_vec.size() * 8) == -1) {
+        report_error("read");
+      }
+    }
+    // our actual results are in slots 1,3,5, ... of this structure
+    for (uint32_t i = 1; i < temp_result_vec.size(); i += 2) {
+      results[i / 2] = temp_result_vec[i];
+    }
+    for (uint32_t i = 2; i < temp_result_vec.size(); i += 2) {
+      if (ids[i / 2 - 1] != temp_result_vec[i]) {
+        report_error("event mismatch");
+      }
+    }
+  }
+
+  bool is_working() { return working; }
+
+private:
+  void report_error(const std::string &) { working = false; }
+};
+#endif

cmake/toolchains-ci/riscv64-linux-gnu.cmake

@@ -0,0 +1,4 @@
+set(CMAKE_SYSTEM_NAME Linux)
+set(CMAKE_SYSTEM_PROCESSOR riscv64)
+
+set(CMAKE_CROSSCOMPILING_EMULATOR "qemu-riscv64-static")

fuzz/from_chars.cc

@@ -19,7 +19,7 @@ fast_float::chars_format arbitrary_format(FuzzedDataProvider &fdp) {
   return chars_format::general;
 }
 
-extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
+extern "C" int LLVMFuzzerTestOneInput(uint8_t const *data, size_t size) {
   FuzzedDataProvider fdp(data, size);
   fast_float::chars_format format = arbitrary_format(fdp);
   double result_d = 0.0;

include/fast_float/ascii_number.h

@@ -45,7 +45,7 @@ fastfloat_really_inline constexpr uint64_t byteswap(uint64_t val) {
 // Read 8 UC into a u64. Truncates UC if not char.
 template <typename UC>
 fastfloat_really_inline FASTFLOAT_CONSTEXPR20 uint64_t
-read8_to_u64(const UC *chars) {
+read8_to_u64(UC const *chars) {
   if (cpp20_and_in_constexpr() || !std::is_same<UC, char>::value) {
     uint64_t val = 0;
     for (int i = 0; i < 8; ++i) {
@@ -65,9 +65,9 @@ read8_to_u64(const UC *chars) {
 
 #ifdef FASTFLOAT_SSE2
 
-fastfloat_really_inline uint64_t simd_read8_to_u64(const __m128i data) {
+fastfloat_really_inline uint64_t simd_read8_to_u64(__m128i const data) {
   FASTFLOAT_SIMD_DISABLE_WARNINGS
-  const __m128i packed = _mm_packus_epi16(data, data);
+  __m128i const packed = _mm_packus_epi16(data, data);
 #ifdef FASTFLOAT_64BIT
   return uint64_t(_mm_cvtsi128_si64(packed));
 #else
@@ -79,26 +79,26 @@ fastfloat_really_inline uint64_t simd_read8_to_u64(const __m128i data) {
   FASTFLOAT_SIMD_RESTORE_WARNINGS
 }
 
-fastfloat_really_inline uint64_t simd_read8_to_u64(const char16_t *chars) {
+fastfloat_really_inline uint64_t simd_read8_to_u64(char16_t const *chars) {
   FASTFLOAT_SIMD_DISABLE_WARNINGS
   return simd_read8_to_u64(
-      _mm_loadu_si128(reinterpret_cast<const __m128i *>(chars)));
+      _mm_loadu_si128(reinterpret_cast<__m128i const *>(chars)));
   FASTFLOAT_SIMD_RESTORE_WARNINGS
 }
 
 #elif defined(FASTFLOAT_NEON)
 
-fastfloat_really_inline uint64_t simd_read8_to_u64(const uint16x8_t data) {
+fastfloat_really_inline uint64_t simd_read8_to_u64(uint16x8_t const data) {
   FASTFLOAT_SIMD_DISABLE_WARNINGS
   uint8x8_t utf8_packed = vmovn_u16(data);
   return vget_lane_u64(vreinterpret_u64_u8(utf8_packed), 0);
   FASTFLOAT_SIMD_RESTORE_WARNINGS
 }
 
-fastfloat_really_inline uint64_t simd_read8_to_u64(const char16_t *chars) {
+fastfloat_really_inline uint64_t simd_read8_to_u64(char16_t const *chars) {
   FASTFLOAT_SIMD_DISABLE_WARNINGS
   return simd_read8_to_u64(
-      vld1q_u16(reinterpret_cast<const uint16_t *>(chars)));
+      vld1q_u16(reinterpret_cast<uint16_t const *>(chars)));
   FASTFLOAT_SIMD_RESTORE_WARNINGS
 }
 
@@ -118,9 +118,9 @@ uint64_t simd_read8_to_u64(UC const *) {
 // credit  @aqrit
 fastfloat_really_inline FASTFLOAT_CONSTEXPR14 uint32_t
 parse_eight_digits_unrolled(uint64_t val) {
-  const uint64_t mask = 0x000000FF000000FF;
-  const uint64_t mul1 = 0x000F424000000064; // 100 + (1000000ULL << 32)
-  const uint64_t mul2 = 0x0000271000000001; // 1 + (10000ULL << 32)
+  uint64_t const mask = 0x000000FF000000FF;
+  uint64_t const mul1 = 0x000F424000000064; // 100 + (1000000ULL << 32)
+  uint64_t const mul2 = 0x0000271000000001; // 1 + (10000ULL << 32)
   val -= 0x3030303030303030;
   val = (val * 10) + (val >> 8); // val = (val * 2561) >> 8;
   val = (((val & mask) * mul1) + (((val >> 16) & mask) * mul2)) >> 32;
@@ -150,20 +150,20 @@ is_made_of_eight_digits_fast(uint64_t val) noexcept {
 // Using this style (instead of is_made_of_eight_digits_fast() then
 // parse_eight_digits_unrolled()) ensures we don't load SIMD registers twice.
 fastfloat_really_inline FASTFLOAT_CONSTEXPR20 bool
-simd_parse_if_eight_digits_unrolled(const char16_t *chars,
+simd_parse_if_eight_digits_unrolled(char16_t const *chars,
                                     uint64_t &i) noexcept {
   if (cpp20_and_in_constexpr()) {
     return false;
   }
 #ifdef FASTFLOAT_SSE2
   FASTFLOAT_SIMD_DISABLE_WARNINGS
-  const __m128i data =
-      _mm_loadu_si128(reinterpret_cast<const __m128i *>(chars));
+  __m128i const data =
+      _mm_loadu_si128(reinterpret_cast<__m128i const *>(chars));
 
   // (x - '0') <= 9
   // http://0x80.pl/articles/simd-parsing-int-sequences.html
-  const __m128i t0 = _mm_add_epi16(data, _mm_set1_epi16(32720));
-  const __m128i t1 = _mm_cmpgt_epi16(t0, _mm_set1_epi16(-32759));
+  __m128i const t0 = _mm_add_epi16(data, _mm_set1_epi16(32720));
+  __m128i const t1 = _mm_cmpgt_epi16(t0, _mm_set1_epi16(-32759));
 
   if (_mm_movemask_epi8(t1) == 0) {
     i = i * 100000000 + parse_eight_digits_unrolled(simd_read8_to_u64(data));
@@ -173,12 +173,12 @@ simd_parse_if_eight_digits_unrolled(const char16_t *chars,
   FASTFLOAT_SIMD_RESTORE_WARNINGS
 #elif defined(FASTFLOAT_NEON)
   FASTFLOAT_SIMD_DISABLE_WARNINGS
-  const uint16x8_t data = vld1q_u16(reinterpret_cast<const uint16_t *>(chars));
+  uint16x8_t const data = vld1q_u16(reinterpret_cast<uint16_t const *>(chars));
 
   // (x - '0') <= 9
   // http://0x80.pl/articles/simd-parsing-int-sequences.html
-  const uint16x8_t t0 = vsubq_u16(data, vmovq_n_u16('0'));
-  const uint16x8_t mask = vcltq_u16(t0, vmovq_n_u16('9' - '0' + 1));
+  uint16x8_t const t0 = vsubq_u16(data, vmovq_n_u16('0'));
+  uint16x8_t const mask = vcltq_u16(t0, vmovq_n_u16('9' - '0' + 1));
 
   if (vminvq_u16(mask) == 0xFFFF) {
     i = i * 100000000 + parse_eight_digits_unrolled(simd_read8_to_u64(data));
@@ -208,7 +208,7 @@ bool simd_parse_if_eight_digits_unrolled(UC const *, uint64_t &) {
 
 template <typename UC, FASTFLOAT_ENABLE_IF(!std::is_same<UC, char>::value) = 0>
 fastfloat_really_inline FASTFLOAT_CONSTEXPR20 void
-loop_parse_if_eight_digits(const UC *&p, const UC *const pend, uint64_t &i) {
+loop_parse_if_eight_digits(UC const *&p, UC const *const pend, uint64_t &i) {
   if (!has_simd_opt<UC>()) {
     return;
   }
@@ -220,7 +220,7 @@ loop_parse_if_eight_digits(const UC *&p, const UC *const pend, uint64_t &i) {
 }
 
 fastfloat_really_inline FASTFLOAT_CONSTEXPR20 void
-loop_parse_if_eight_digits(const char *&p, const char *const pend,
+loop_parse_if_eight_digits(char const *&p, char const *const pend,
                            uint64_t &i) {
   // optimizes better than parse_if_eight_digits_unrolled() for UC = char.
   while ((std::distance(p, pend) >= 8) &&
@@ -259,12 +259,12 @@ template <typename UC> struct parsed_number_string_t {
   bool valid{false};
   bool too_many_digits{false};
   // contains the range of the significant digits
-  span<const UC> integer{};  // non-nullable
-  span<const UC> fraction{}; // nullable
+  span<UC const> integer{};  // non-nullable
+  span<UC const> fraction{}; // nullable
   parse_error error{parse_error::no_error};
 };
 
-using byte_span = span<const char>;
+using byte_span = span<char const>;
 using parsed_number_string = parsed_number_string_t<char>;
 
 template <typename UC>
@@ -279,33 +279,33 @@ report_parse_error(UC const *p, parse_error error) {
 
 // Assuming that you use no more than 19 digits, this will
 // parse an ASCII string.
-template <typename UC>
+template <bool basic_json_fmt, typename UC>
 fastfloat_really_inline FASTFLOAT_CONSTEXPR20 parsed_number_string_t<UC>
 parse_number_string(UC const *p, UC const *pend,
                     parse_options_t<UC> options) noexcept {
-  chars_format const fmt = options.format;
+  chars_format const fmt = detail::adjust_for_feature_macros(options.format);
   UC const decimal_point = options.decimal_point;
 
   parsed_number_string_t<UC> answer;
   answer.valid = false;
   answer.too_many_digits = false;
+  // assume p < pend, so dereference without checks;
   answer.negative = (*p == UC('-'));
-#ifdef FASTFLOAT_ALLOWS_LEADING_PLUS // disabled by default
-  if ((*p == UC('-')) || (!(fmt & FASTFLOAT_JSONFMT) && *p == UC('+'))) {
-#else
-  if (*p == UC('-')) { // C++17 20.19.3.(7.1) explicitly forbids '+' sign here
-#endif
+  // C++17 20.19.3.(7.1) explicitly forbids '+' sign here
+  if ((*p == UC('-')) || (uint64_t(fmt & chars_format::allow_leading_plus) &&
+                          !basic_json_fmt && *p == UC('+'))) {
     ++p;
     if (p == pend) {
       return report_parse_error<UC>(
           p, parse_error::missing_integer_or_dot_after_sign);
     }
-    if (fmt & FASTFLOAT_JSONFMT) {
+    FASTFLOAT_IF_CONSTEXPR17(basic_json_fmt) {
       if (!is_integer(*p)) { // a sign must be followed by an integer
         return report_parse_error<UC>(p,
                                       parse_error::missing_integer_after_sign);
       }
-    } else {
+    }
+    else {
       if (!is_integer(*p) &&
           (*p !=
            decimal_point)) { // a sign must be followed by an integer or the dot
@@ -328,8 +328,8 @@ parse_number_string(UC const *p, UC const *pend,
   }
   UC const *const end_of_integer_part = p;
   int64_t digit_count = int64_t(end_of_integer_part - start_digits);
-  answer.integer = span<const UC>(start_digits, size_t(digit_count));
-  if (fmt & FASTFLOAT_JSONFMT) {
+  answer.integer = span<UC const>(start_digits, size_t(digit_count));
+  FASTFLOAT_IF_CONSTEXPR17(basic_json_fmt) {
     // at least 1 digit in integer part, without leading zeros
     if (digit_count == 0) {
       return report_parse_error<UC>(p, parse_error::no_digits_in_integer_part);
@@ -341,7 +341,7 @@ parse_number_string(UC const *p, UC const *pend,
   }
 
   int64_t exponent = 0;
-  const bool has_decimal_point = (p != pend) && (*p == decimal_point);
+  bool const has_decimal_point = (p != pend) && (*p == decimal_point);
   if (has_decimal_point) {
     ++p;
     UC const *before = p;
@@ -355,23 +355,23 @@ parse_number_string(UC const *p, UC const *pend,
       i = i * 10 + digit; // in rare cases, this will overflow, but that's ok
     }
     exponent = before - p;
-    answer.fraction = span<const UC>(before, size_t(p - before));
+    answer.fraction = span<UC const>(before, size_t(p - before));
     digit_count -= exponent;
   }
-  if (fmt & FASTFLOAT_JSONFMT) {
+  FASTFLOAT_IF_CONSTEXPR17(basic_json_fmt) {
     // at least 1 digit in fractional part
     if (has_decimal_point && exponent == 0) {
       return report_parse_error<UC>(p,
                                     parse_error::no_digits_in_fractional_part);
     }
-  } else if (digit_count ==
-             0) { // we must have encountered at least one integer!
+  }
+  else if (digit_count == 0) { // we must have encountered at least one integer!
     return report_parse_error<UC>(p, parse_error::no_digits_in_mantissa);
   }
   int64_t exp_number = 0; // explicit exponential part
-  if (((fmt & chars_format::scientific) && (p != pend) &&
+  if ((uint64_t(fmt & chars_format::scientific) && (p != pend) &&
        ((UC('e') == *p) || (UC('E') == *p))) ||
-      ((fmt & FASTFLOAT_FORTRANFMT) && (p != pend) &&
+      (uint64_t(fmt & detail::basic_fortran_fmt) && (p != pend) &&
        ((UC('+') == *p) || (UC('-') == *p) || (UC('d') == *p) ||
         (UC('D') == *p)))) {
     UC const *location_of_e = p;
@@ -389,7 +389,7 @@ parse_number_string(UC const *p, UC const *pend,
       ++p;
     }
     if ((p == pend) || !is_integer(*p)) {
-      if (!(fmt & chars_format::fixed)) {
+      if (!uint64_t(fmt & chars_format::fixed)) {
         // The exponential part is invalid for scientific notation, so it must
         // be a trailing token for fixed notation. However, fixed notation is
         // disabled, so report a scientific notation error.
@@ -412,7 +412,8 @@ parse_number_string(UC const *p, UC const *pend,
     }
   } else {
     // If it scientific and not fixed, we have to bail out.
-    if ((fmt & chars_format::scientific) && !(fmt & chars_format::fixed)) {
+    if (uint64_t(fmt & chars_format::scientific) &&
+        !uint64_t(fmt & chars_format::fixed)) {
       return report_parse_error<UC>(p, parse_error::missing_exponential_part);
     }
   }
@@ -440,17 +441,17 @@ parse_number_string(UC const *p, UC const *pend,
     if (digit_count > 19) {
       answer.too_many_digits = true;
       // Let us start again, this time, avoiding overflows.
-      // We don't need to check if is_integer, since we use the
+      // We don't need to call if is_integer, since we use the
       // pre-tokenized spans from above.
       i = 0;
       p = answer.integer.ptr;
       UC const *int_end = p + answer.integer.len();
-      const uint64_t minimal_nineteen_digit_integer{1000000000000000000};
+      uint64_t const minimal_nineteen_digit_integer{1000000000000000000};
       while ((i < minimal_nineteen_digit_integer) && (p != int_end)) {
         i = i * 10 + uint64_t(*p - UC('0'));
         ++p;
       }
-      if (i >= minimal_nineteen_digit_integer) { // We have a big integers
+      if (i >= minimal_nineteen_digit_integer) { // We have a big integer
         exponent = end_of_integer_part - p + exp_number;
       } else { // We have a value with a fractional component.
         p = answer.fraction.ptr;
@@ -471,22 +472,30 @@ parse_number_string(UC const *p, UC const *pend,
 
 template <typename T, typename UC>
 fastfloat_really_inline FASTFLOAT_CONSTEXPR20 from_chars_result_t<UC>
-parse_int_string(UC const *p, UC const *pend, T &value, int base) {
+parse_int_string(UC const *p, UC const *pend, T &value,
+                 parse_options_t<UC> options) {
+  chars_format const fmt = detail::adjust_for_feature_macros(options.format);
+  int const base = options.base;
+
   from_chars_result_t<UC> answer;
 
   UC const *const first = p;
 
-  bool negative = (*p == UC('-'));
+  bool const negative = (*p == UC('-'));
+#ifdef FASTFLOAT_VISUAL_STUDIO
+#pragma warning(push)
+#pragma warning(disable : 4127)
+#endif
   if (!std::is_signed<T>::value && negative) {
+#ifdef FASTFLOAT_VISUAL_STUDIO
+#pragma warning(pop)
+#endif
     answer.ec = std::errc::invalid_argument;
     answer.ptr = first;
     return answer;
   }
-#ifdef FASTFLOAT_ALLOWS_LEADING_PLUS // disabled by default
-  if ((*p == UC('-')) || (*p == UC('+'))) {
-#else
-  if (*p == UC('-')) {
-#endif
+  if ((*p == UC('-')) ||
+      (uint64_t(fmt & chars_format::allow_leading_plus) && (*p == UC('+')))) {
     ++p;
   }
 
@@ -496,7 +505,7 @@ parse_int_string(UC const *p, UC const *pend, T &value, int base) {
     ++p;
   }
 
-  const bool has_leading_zeros = p > start_num;
+  bool const has_leading_zeros = p > start_num;
 
   UC const *const start_digits = p;
 

include/fast_float/bigint.h

@@ -43,8 +43,8 @@ template <uint16_t size> struct stackvec {
   uint16_t length{0};
 
   stackvec() = default;
-  stackvec(const stackvec &) = delete;
-  stackvec &operator=(const stackvec &) = delete;
+  stackvec(stackvec const &) = delete;
+  stackvec &operator=(stackvec const &) = delete;
   stackvec(stackvec &&) = delete;
   stackvec &operator=(stackvec &&other) = delete;
 
@@ -57,10 +57,12 @@ template <uint16_t size> struct stackvec {
     FASTFLOAT_DEBUG_ASSERT(index < length);
     return data[index];
   }
+
   FASTFLOAT_CONSTEXPR14 const limb &operator[](size_t index) const noexcept {
     FASTFLOAT_DEBUG_ASSERT(index < length);
     return data[index];
   }
+
   // index from the end of the container
   FASTFLOAT_CONSTEXPR14 const limb &rindex(size_t index) const noexcept {
     FASTFLOAT_DEBUG_ASSERT(index < length);
@@ -72,14 +74,19 @@ template <uint16_t size> struct stackvec {
   FASTFLOAT_CONSTEXPR14 void set_len(size_t len) noexcept {
     length = uint16_t(len);
   }
+
   constexpr size_t len() const noexcept { return length; }
+
   constexpr bool is_empty() const noexcept { return length == 0; }
+
   constexpr size_t capacity() const noexcept { return size; }
+
   // append item to vector, without bounds checking
   FASTFLOAT_CONSTEXPR14 void push_unchecked(limb value) noexcept {
     data[length] = value;
     length++;
   }
+
   // append item to vector, returning if item was added
   FASTFLOAT_CONSTEXPR14 bool try_push(limb value) noexcept {
     if (len() < capacity()) {
@@ -89,12 +96,14 @@ template <uint16_t size> struct stackvec {
       return false;
     }
   }
+
   // add items to the vector, from a span, without bounds checking
   FASTFLOAT_CONSTEXPR20 void extend_unchecked(limb_span s) noexcept {
     limb *ptr = data + length;
     std::copy_n(s.ptr, s.len(), ptr);
     set_len(len() + s.len());
   }
+
   // try to add items to the vector, returning if items were added
   FASTFLOAT_CONSTEXPR20 bool try_extend(limb_span s) noexcept {
     if (len() + s.len() <= capacity()) {
@@ -104,6 +113,7 @@ template <uint16_t size> struct stackvec {
       return false;
     }
   }
+
   // resize the vector, without bounds checking
   // if the new size is longer than the vector, assign value to each
   // appended item.
@@ -119,6 +129,7 @@ template <uint16_t size> struct stackvec {
       set_len(new_len);
     }
   }
+
   // try to resize the vector, returning if the vector was resized.
   FASTFLOAT_CONSTEXPR20 bool try_resize(size_t new_len, limb value) noexcept {
     if (new_len > capacity()) {
@@ -128,6 +139,7 @@ template <uint16_t size> struct stackvec {
       return true;
     }
   }
+
   // check if any limbs are non-zero after the given index.
   // this needs to be done in reverse order, since the index
   // is relative to the most significant limbs.
@@ -140,6 +152,7 @@ template <uint16_t size> struct stackvec {
     }
     return false;
   }
+
   // normalize the big integer, so most-significant zero limbs are removed.
   FASTFLOAT_CONSTEXPR14 void normalize() noexcept {
     while (len() > 0 && rindex(0) == 0) {
@@ -423,8 +436,9 @@ struct bigint : pow5_tables<> {
   stackvec<bigint_limbs> vec;
 
   FASTFLOAT_CONSTEXPR20 bigint() : vec() {}
-  bigint(const bigint &) = delete;
-  bigint &operator=(const bigint &) = delete;
+
+  bigint(bigint const &) = delete;
+  bigint &operator=(bigint const &) = delete;
   bigint(bigint &&) = delete;
   bigint &operator=(bigint &&other) = delete;
 
@@ -473,7 +487,7 @@ struct bigint : pow5_tables<> {
   // positive, this is larger, otherwise they are equal.
   // the limbs are stored in little-endian order, so we
   // must compare the limbs in ever order.
-  FASTFLOAT_CONSTEXPR20 int compare(const bigint &other) const noexcept {
+  FASTFLOAT_CONSTEXPR20 int compare(bigint const &other) const noexcept {
     if (vec.len() > other.vec.len()) {
       return 1;
     } else if (vec.len() < other.vec.len()) {
@@ -527,7 +541,7 @@ struct bigint : pow5_tables<> {
     } else if (!vec.is_empty()) {
       // move limbs
       limb *dst = vec.data + n;
-      const limb *src = vec.data;
+      limb const *src = vec.data;
       std::copy_backward(src, src + vec.len(), dst + vec.len());
       // fill in empty limbs
       limb *first = vec.data;

include/fast_float/constexpr_feature_detect.h

@@ -8,7 +8,7 @@
 #endif
 
 // Testing for https://wg21.link/N3652, adopted in C++14
-#if __cpp_constexpr >= 201304
+#if defined(__cpp_constexpr) && __cpp_constexpr >= 201304
 #define FASTFLOAT_CONSTEXPR14 constexpr
 #else
 #define FASTFLOAT_CONSTEXPR14
@@ -27,8 +27,15 @@
 #define FASTFLOAT_HAS_IS_CONSTANT_EVALUATED 0
 #endif
 
+#if defined(__cpp_if_constexpr) && __cpp_if_constexpr >= 201606L
+#define FASTFLOAT_IF_CONSTEXPR17(x) if constexpr (x)
+#else
+#define FASTFLOAT_IF_CONSTEXPR17(x) if (x)
+#endif
+
 // Testing for relevant C++20 constexpr library features
 #if FASTFLOAT_HAS_IS_CONSTANT_EVALUATED && FASTFLOAT_HAS_BIT_CAST &&           \
+    defined(__cpp_lib_constexpr_algorithms) &&                                 \
     __cpp_lib_constexpr_algorithms >= 201806L /*For std::copy and std::fill*/
 #define FASTFLOAT_CONSTEXPR20 constexpr
 #define FASTFLOAT_IS_CONSTEXPR 1

include/fast_float/decimal_to_binary.h

@@ -20,7 +20,7 @@ namespace fast_float {
 template <int bit_precision>
 fastfloat_really_inline FASTFLOAT_CONSTEXPR20 value128
 compute_product_approximation(int64_t q, uint64_t w) {
-  const int index = 2 * int(q - powers::smallest_power_of_five);
+  int const index = 2 * int(q - powers::smallest_power_of_five);
   // For small values of q, e.g., q in [0,27], the answer is always exact
   // because The line value128 firstproduct = full_multiplication(w,
   // power_of_five_128[index]); gives the exact answer.
@@ -93,8 +93,8 @@ compute_error(int64_t q, uint64_t w) noexcept {
   return compute_error_scaled<binary>(q, product.high, lz);
 }
 
-// w * 10 ** q
-// The returned value should be a valid ieee64 number that simply need to be
+// Computers w * 10 ** q.
+// The returned value should be a valid number that simply needs to be
 // packed. However, in some very rare cases, the computation will fail. In such
 // cases, we return an adjusted_mantissa with a negative power of 2: the caller
 // should recompute in such cases.
@@ -158,7 +158,8 @@ compute_float(int64_t q, uint64_t w) noexcept {
     // next line is safe because -answer.power2 + 1 < 64
     answer.mantissa >>= -answer.power2 + 1;
     // Thankfully, we can't have both "round-to-even" and subnormals because
-    // "round-to-even" only occurs for powers close to 0.
+    // "round-to-even" only occurs for powers close to 0 in the 32-bit and
+    // and 64-bit case (with no more than 19 digits).
     answer.mantissa += (answer.mantissa & 1); // round up
     answer.mantissa >>= 1;
     // There is a weird scenario where we don't have a subnormal but just.

include/fast_float/digit_comparison.h

@@ -38,11 +38,8 @@ constexpr static uint64_t powers_of_ten_uint64[] = {1UL,
 // this algorithm is not even close to optimized, but it has no practical
 // effect on performance: in order to have a faster algorithm, we'd need
 // to slow down performance for faster algorithms, and this is still fast.
-template <typename UC>
 fastfloat_really_inline FASTFLOAT_CONSTEXPR14 int32_t
-scientific_exponent(parsed_number_string_t<UC> &num) noexcept {
-  uint64_t mantissa = num.mantissa;
-  int32_t exponent = int32_t(num.exponent);
+scientific_exponent(uint64_t mantissa, int32_t exponent) noexcept {
   while (mantissa >= 10000) {
     mantissa /= 10000;
     exponent += 4;
@@ -62,7 +59,7 @@ scientific_exponent(parsed_number_string_t<UC> &num) noexcept {
 template <typename T>
 fastfloat_really_inline FASTFLOAT_CONSTEXPR20 adjusted_mantissa
 to_extended(T value) noexcept {
-  using equiv_uint = typename binary_format<T>::equiv_uint;
+  using equiv_uint = equiv_uint_t<T>;
   constexpr equiv_uint exponent_mask = binary_format<T>::exponent_mask();
   constexpr equiv_uint mantissa_mask = binary_format<T>::mantissa_mask();
   constexpr equiv_uint hidden_bit_mask = binary_format<T>::hidden_bit_mask();
@@ -143,8 +140,8 @@ template <typename callback>
 fastfloat_really_inline FASTFLOAT_CONSTEXPR14 void
 round_nearest_tie_even(adjusted_mantissa &am, int32_t shift,
                        callback cb) noexcept {
-  const uint64_t mask = (shift == 64) ? UINT64_MAX : (uint64_t(1) << shift) - 1;
-  const uint64_t halfway = (shift == 0) ? 0 : uint64_t(1) << (shift - 1);
+  uint64_t const mask = (shift == 64) ? UINT64_MAX : (uint64_t(1) << shift) - 1;
+  uint64_t const halfway = (shift == 0) ? 0 : uint64_t(1) << (shift - 1);
   uint64_t truncated_bits = am.mantissa & mask;
   bool is_above = truncated_bits > halfway;
   bool is_halfway = truncated_bits == halfway;
@@ -170,6 +167,7 @@ round_down(adjusted_mantissa &am, int32_t shift) noexcept {
   }
   am.power2 += shift;
 }
+
 template <typename UC>
 fastfloat_really_inline FASTFLOAT_CONSTEXPR20 void
 skip_zeros(UC const *&first, UC const *last) noexcept {
@@ -213,15 +211,16 @@ is_truncated(UC const *first, UC const *last) noexcept {
   }
   return false;
 }
+
 template <typename UC>
 fastfloat_really_inline FASTFLOAT_CONSTEXPR20 bool
-is_truncated(span<const UC> s) noexcept {
+is_truncated(span<UC const> s) noexcept {
   return is_truncated(s.ptr, s.ptr + s.len());
 }
 
 template <typename UC>
 fastfloat_really_inline FASTFLOAT_CONSTEXPR20 void
-parse_eight_digits(const UC *&p, limb &value, size_t &counter,
+parse_eight_digits(UC const *&p, limb &value, size_t &counter,
                    size_t &count) noexcept {
   value = value * 100000000 + parse_eight_digits_unrolled(p);
   p += 8;
@@ -396,7 +395,7 @@ inline FASTFLOAT_CONSTEXPR20 adjusted_mantissa negative_digit_comp(
     FASTFLOAT_ASSERT(real_digits.pow2(uint32_t(-pow2_exp)));
   }
 
-  // compare digits, and use it to director rounding
+  // compare digits, and use it to direct rounding
   int ord = real_digits.compare(theor_digits);
   adjusted_mantissa answer = am;
   round<T>(answer, [ord](adjusted_mantissa &a, int32_t shift) {
@@ -417,7 +416,7 @@ inline FASTFLOAT_CONSTEXPR20 adjusted_mantissa negative_digit_comp(
   return answer;
 }
 
-// parse the significant digits as a big integer to unambiguously round the
+// parse the significant digits as a big integer to unambiguously round
 // the significant digits. here, we are trying to determine how to round
 // an extended float representation close to `b+h`, halfway between `b`
 // (the float rounded-down) and `b+u`, the next positive float. this
@@ -436,7 +435,8 @@ digit_comp(parsed_number_string_t<UC> &num, adjusted_mantissa am) noexcept {
   // remove the invalid exponent bias
   am.power2 -= invalid_am_bias;
 
-  int32_t sci_exp = scientific_exponent(num);
+  int32_t sci_exp =
+      scientific_exponent(num.mantissa, static_cast<int32_t>(num.exponent));
   size_t max_digits = binary_format<T>::max_digits();
   size_t digits = 0;
   bigint bigmant;

include/fast_float/fast_float.h

@@ -31,26 +31,61 @@ namespace fast_float {
  * `scientific`.
  */
 template <typename T, typename UC = char,
-          typename = FASTFLOAT_ENABLE_IF(is_supported_float_type<T>())>
+          typename = FASTFLOAT_ENABLE_IF(is_supported_float_type<T>::value)>
 FASTFLOAT_CONSTEXPR20 from_chars_result_t<UC>
 from_chars(UC const *first, UC const *last, T &value,
            chars_format fmt = chars_format::general) noexcept;
 
 /**
  * Like from_chars, but accepts an `options` argument to govern number parsing.
+ * Both for floating-point types and integer types.
  */
 template <typename T, typename UC = char>
 FASTFLOAT_CONSTEXPR20 from_chars_result_t<UC>
 from_chars_advanced(UC const *first, UC const *last, T &value,
                     parse_options_t<UC> options) noexcept;
+
+/**
+ * This function multiplies an integer number by a power of 10 and returns
+ * the result as a double precision floating-point value that is correctly
+ * rounded. The resulting floating-point value is the closest floating-point
+ * value, using the "round to nearest, tie to even" convention for values that
+ * would otherwise fall right in-between two values. That is, we provide exact
+ * conversion according to the IEEE standard.
+ *
+ * On overflow infinity is returned, on underflow 0 is returned.
+ *
+ * The implementation does not throw and does not allocate memory (e.g., with
+ * `new` or `malloc`).
+ */
+FASTFLOAT_CONSTEXPR20 inline double
+integer_times_pow10(uint64_t mantissa, int decimal_exponent) noexcept;
+FASTFLOAT_CONSTEXPR20 inline double
+integer_times_pow10(int64_t mantissa, int decimal_exponent) noexcept;
+
+/**
+ * This function is a template overload of `integer_times_pow10()`
+ * that returns a floating-point value of type `T` that is one of
+ * supported floating-point types (e.g. `double`, `float`).
+ */
+template <typename T>
+FASTFLOAT_CONSTEXPR20
+    typename std::enable_if<is_supported_float_type<T>::value, T>::type
+    integer_times_pow10(uint64_t mantissa, int decimal_exponent) noexcept;
+template <typename T>
+FASTFLOAT_CONSTEXPR20
+    typename std::enable_if<is_supported_float_type<T>::value, T>::type
+    integer_times_pow10(int64_t mantissa, int decimal_exponent) noexcept;
+
 /**
  * from_chars for integer types.
  */
 template <typename T, typename UC = char,
-          typename = FASTFLOAT_ENABLE_IF(!is_supported_float_type<T>())>
+          typename = FASTFLOAT_ENABLE_IF(is_supported_integer_type<T>::value)>
 FASTFLOAT_CONSTEXPR20 from_chars_result_t<UC>
 from_chars(UC const *first, UC const *last, T &value, int base = 10) noexcept;
 
 } // namespace fast_float
+
 #include "parse_number.h"
 #endif // FASTFLOAT_FAST_FLOAT_H

include/fast_float/float_common.h

@@ -5,49 +5,81 @@
 #include <cstdint>
 #include <cassert>
 #include <cstring>
+#include <limits>
 #include <type_traits>
 #include <system_error>
 #ifdef __has_include
-#if __has_include(<stdfloat>) && (__cplusplus > 202002L || _MSVC_LANG > 202002L)
+#if __has_include(<stdfloat>) && (__cplusplus > 202002L || (defined(_MSVC_LANG) && (_MSVC_LANG > 202002L)))
 #include <stdfloat>
 #endif
 #endif
 #include "constexpr_feature_detect.h"
 
+#define FASTFLOAT_VERSION_MAJOR 8
+#define FASTFLOAT_VERSION_MINOR 1
+#define FASTFLOAT_VERSION_PATCH 0
+
+#define FASTFLOAT_STRINGIZE_IMPL(x) #x
+#define FASTFLOAT_STRINGIZE(x) FASTFLOAT_STRINGIZE_IMPL(x)
+
+#define FASTFLOAT_VERSION_STR                                                  \
+  FASTFLOAT_STRINGIZE(FASTFLOAT_VERSION_MAJOR)                                 \
+  "." FASTFLOAT_STRINGIZE(FASTFLOAT_VERSION_MINOR) "." FASTFLOAT_STRINGIZE(    \
+      FASTFLOAT_VERSION_PATCH)
+
+#define FASTFLOAT_VERSION                                                      \
+  (FASTFLOAT_VERSION_MAJOR * 10000 + FASTFLOAT_VERSION_MINOR * 100 +           \
+   FASTFLOAT_VERSION_PATCH)
+
 namespace fast_float {
 
-#define FASTFLOAT_JSONFMT (1 << 5)
-#define FASTFLOAT_FORTRANFMT (1 << 6)
+enum class chars_format : uint64_t;
 
-enum chars_format {
+namespace detail {
+constexpr chars_format basic_json_fmt = chars_format(1 << 5);
+constexpr chars_format basic_fortran_fmt = chars_format(1 << 6);
+} // namespace detail
+
+enum class chars_format : uint64_t {
   scientific = 1 << 0,
   fixed = 1 << 2,
   hex = 1 << 3,
   no_infnan = 1 << 4,
   // RFC 8259: https://datatracker.ietf.org/doc/html/rfc8259#section-6
-  json = FASTFLOAT_JSONFMT | fixed | scientific | no_infnan,
+  json = uint64_t(detail::basic_json_fmt) | fixed | scientific | no_infnan,
   // Extension of RFC 8259 where, e.g., "inf" and "nan" are allowed.
-  json_or_infnan = FASTFLOAT_JSONFMT | fixed | scientific,
-  fortran = FASTFLOAT_FORTRANFMT | fixed | scientific,
-  general = fixed | scientific
+  json_or_infnan = uint64_t(detail::basic_json_fmt) | fixed | scientific,
+  fortran = uint64_t(detail::basic_fortran_fmt) | fixed | scientific,
+  general = fixed | scientific,
+  allow_leading_plus = 1 << 7,
+  skip_white_space = 1 << 8,
 };
 
 template <typename UC> struct from_chars_result_t {
   UC const *ptr;
   std::errc ec;
+
+  // https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2023/p2497r0.html
+  constexpr explicit operator bool() const noexcept {
+    return ec == std::errc();
+  }
 };
+
 using from_chars_result = from_chars_result_t<char>;
 
 template <typename UC> struct parse_options_t {
   constexpr explicit parse_options_t(chars_format fmt = chars_format::general,
-                                     UC dot = UC('.'))
-      : format(fmt), decimal_point(dot) {}
+                                     UC dot = UC('.'), int b = 10)
+      : format(fmt), decimal_point(dot), base(b) {}
 
   /** Which number formats are accepted */
   chars_format format;
   /** The character used as decimal point */
   UC decimal_point;
+  /** The base used for integers */
+  int base;
 };
+
 using parse_options = parse_options_t<char>;
 
 } // namespace fast_float
@@ -61,11 +93,12 @@ using parse_options = parse_options_t<char>;
      defined(__MINGW64__) || defined(__s390x__) ||                             \
      (defined(__ppc64__) || defined(__PPC64__) || defined(__ppc64le__) ||      \
       defined(__PPC64LE__)) ||                                                 \
-     defined(__loongarch64))
+     defined(__loongarch64) || (defined(__riscv) && __riscv_xlen == 64))
 #define FASTFLOAT_64BIT 1
 #elif (defined(__i386) || defined(__i386__) || defined(_M_IX86) ||             \
        defined(__arm__) || defined(_M_ARM) || defined(__ppc__) ||              \
-       defined(__MINGW32__) || defined(__EMSCRIPTEN__))
+       defined(__MINGW32__) || defined(__EMSCRIPTEN__) ||                      \
+       (defined(__riscv) && __riscv_xlen == 32))
 #define FASTFLOAT_32BIT 1
 #else
   // Need to check incrementally, since SIZE_MAX is a size_t, avoid overflow.
@@ -194,32 +227,58 @@ fastfloat_really_inline constexpr bool cpp20_and_in_constexpr() {
 }
 
 template <typename T>
-fastfloat_really_inline constexpr bool is_supported_float_type() {
-  return std::is_same<T, float>::value || std::is_same<T, double>::value
-#if __STDCPP_FLOAT32_T__
-         || std::is_same<T, std::float32_t>::value
+struct is_supported_float_type
+    : std::integral_constant<
+          bool, std::is_same<T, double>::value || std::is_same<T, float>::value
+#ifdef __STDCPP_FLOAT64_T__
+                    || std::is_same<T, std::float64_t>::value
 #endif
-#if __STDCPP_FLOAT64_T__
-         || std::is_same<T, std::float64_t>::value
+#ifdef __STDCPP_FLOAT32_T__
+                    || std::is_same<T, std::float32_t>::value
 #endif
-      ;
-}
+#ifdef __STDCPP_FLOAT16_T__
+                    || std::is_same<T, std::float16_t>::value
+#endif
+#ifdef __STDCPP_BFLOAT16_T__
+                    || std::is_same<T, std::bfloat16_t>::value
+#endif
+          > {
+};
+
+template <typename T>
+using equiv_uint_t = typename std::conditional<
+    sizeof(T) == 1, uint8_t,
+    typename std::conditional<
+        sizeof(T) == 2, uint16_t,
+        typename std::conditional<sizeof(T) == 4, uint32_t,
+                                  uint64_t>::type>::type>::type;
+
+template <typename T> struct is_supported_integer_type : std::is_integral<T> {};
 
 template <typename UC>
-fastfloat_really_inline constexpr bool is_supported_char_type() {
-  return std::is_same<UC, char>::value || std::is_same<UC, wchar_t>::value ||
-         std::is_same<UC, char16_t>::value || std::is_same<UC, char32_t>::value;
-}
+struct is_supported_char_type
+    : std::integral_constant<bool, std::is_same<UC, char>::value ||
+                                       std::is_same<UC, wchar_t>::value ||
+                                       std::is_same<UC, char16_t>::value ||
+                                       std::is_same<UC, char32_t>::value
+#ifdef __cpp_char8_t
+                                       || std::is_same<UC, char8_t>::value
+#endif
+                             > {
+};
 
 // Compares two ASCII strings in a case insensitive manner.
 template <typename UC>
 inline FASTFLOAT_CONSTEXPR14 bool
-fastfloat_strncasecmp(UC const *input1, UC const *input2, size_t length) {
-  char running_diff{0};
+fastfloat_strncasecmp(UC const *actual_mixedcase, UC const *expected_lowercase,
+                      size_t length) {
   for (size_t i = 0; i < length; ++i) {
-    running_diff |= (char(input1[i]) ^ char(input2[i]));
+    UC const actual = actual_mixedcase[i];
+    if ((actual < 256 ? actual | 32 : actual) != expected_lowercase[i]) {
+      return false;
+    }
   }
-  return (running_diff == 0) || (running_diff == 32);
+  return true;
 }
 
 #ifndef FLT_EVAL_METHOD
@@ -228,9 +287,11 @@ fastfloat_strncasecmp(UC const *input1, UC const *input2, size_t length) {
 
 // a pointer and a length to a contiguous block of memory
 template <typename T> struct span {
-  const T *ptr;
+  T const *ptr;
   size_t length;
-  constexpr span(const T *_ptr, size_t _length) : ptr(_ptr), length(_length) {}
+
+  constexpr span(T const *_ptr, size_t _length) : ptr(_ptr), length(_length) {}
+
   constexpr span() : ptr(nullptr), length(0) {}
 
   constexpr size_t len() const noexcept { return length; }
@@ -244,7 +305,9 @@ template <typename T> struct span {
 struct value128 {
   uint64_t low;
   uint64_t high;
+
   constexpr value128(uint64_t _low, uint64_t _high) : low(_low), high(_high) {}
+
   constexpr value128() : low(0), high(0) {}
 };
 
@@ -343,8 +406,8 @@ full_multiplication(uint64_t a, uint64_t b) {
   // But MinGW on ARM64 doesn't have native support for 64-bit multiplications
   answer.high = __umulh(a, b);
   answer.low = a * b;
-#elif defined(FASTFLOAT_32BIT) ||                                              \
-    (defined(_WIN64) && !defined(__clang__) && !defined(_M_ARM64))
+#elif defined(FASTFLOAT_32BIT) || (defined(_WIN64) && !defined(__clang__) &&   \
+                                   !defined(_M_ARM64) && !defined(__GNUC__))
   answer.low = _umul128(a, b, &answer.high); // _umul128 not available on ARM64
 #elif defined(FASTFLOAT_64BIT) && defined(__SIZEOF_INT128__)
   __uint128_t r = ((__uint128_t)a) * b;
@@ -360,10 +423,12 @@ struct adjusted_mantissa {
   uint64_t mantissa{0};
   int32_t power2{0}; // a negative value indicates an invalid result
   adjusted_mantissa() = default;
-  constexpr bool operator==(const adjusted_mantissa &o) const {
+
+  constexpr bool operator==(adjusted_mantissa const &o) const {
     return mantissa == o.mantissa && power2 == o.power2;
   }
-  constexpr bool operator!=(const adjusted_mantissa &o) const {
+
+  constexpr bool operator!=(adjusted_mantissa const &o) const {
     return mantissa != o.mantissa || power2 != o.power2;
   }
 };
@@ -377,28 +442,27 @@ constexpr uint64_t constant_55555 = 5 * 5 * 5 * 5 * 5;
 template <typename T, typename U = void> struct binary_format_lookup_tables;
 
 template <typename T> struct binary_format : binary_format_lookup_tables<T> {
-  using equiv_uint =
-      typename std::conditional<sizeof(T) == 4, uint32_t, uint64_t>::type;
+  using equiv_uint = equiv_uint_t<T>;
 
-  static inline constexpr int mantissa_explicit_bits();
-  static inline constexpr int minimum_exponent();
-  static inline constexpr int infinite_power();
-  static inline constexpr int sign_index();
-  static inline constexpr int
+  static constexpr int mantissa_explicit_bits();
+  static constexpr int minimum_exponent();
+  static constexpr int infinite_power();
+  static constexpr int sign_index();
+  static constexpr int
   min_exponent_fast_path(); // used when fegetround() == FE_TONEAREST
-  static inline constexpr int max_exponent_fast_path();
-  static inline constexpr int max_exponent_round_to_even();
-  static inline constexpr int min_exponent_round_to_even();
-  static inline constexpr uint64_t max_mantissa_fast_path(int64_t power);
-  static inline constexpr uint64_t
+  static constexpr int max_exponent_fast_path();
+  static constexpr int max_exponent_round_to_even();
+  static constexpr int min_exponent_round_to_even();
+  static constexpr uint64_t max_mantissa_fast_path(int64_t power);
+  static constexpr uint64_t
   max_mantissa_fast_path(); // used when fegetround() == FE_TONEAREST
-  static inline constexpr int largest_power_of_ten();
-  static inline constexpr int smallest_power_of_ten();
-  static inline constexpr T exact_power_of_ten(int64_t power);
-  static inline constexpr size_t max_digits();
-  static inline constexpr equiv_uint exponent_mask();
-  static inline constexpr equiv_uint mantissa_mask();
-  static inline constexpr equiv_uint hidden_bit_mask();
+  static constexpr int largest_power_of_ten();
+  static constexpr int smallest_power_of_ten();
+  static constexpr T exact_power_of_ten(int64_t power);
+  static constexpr size_t max_digits();
+  static constexpr equiv_uint exponent_mask();
+  static constexpr equiv_uint mantissa_mask();
+  static constexpr equiv_uint hidden_bit_mask();
 };
 
 template <typename U> struct binary_format_lookup_tables<double, U> {
@@ -506,6 +570,7 @@ template <>
 inline constexpr int binary_format<double>::mantissa_explicit_bits() {
   return 52;
 }
+
 template <>
 inline constexpr int binary_format<float>::mantissa_explicit_bits() {
   return 23;
@@ -534,6 +599,7 @@ inline constexpr int binary_format<float>::min_exponent_round_to_even() {
 template <> inline constexpr int binary_format<double>::minimum_exponent() {
   return -1023;
 }
+
 template <> inline constexpr int binary_format<float>::minimum_exponent() {
   return -127;
 }
@@ -541,6 +607,7 @@ template <> inline constexpr int binary_format<float>::minimum_exponent() {
 template <> inline constexpr int binary_format<double>::infinite_power() {
   return 0x7FF;
 }
+
 template <> inline constexpr int binary_format<float>::infinite_power() {
   return 0xFF;
 }
@@ -548,6 +615,7 @@ template <> inline constexpr int binary_format<float>::infinite_power() {
 template <> inline constexpr int binary_format<double>::sign_index() {
   return 63;
 }
+
 template <> inline constexpr int binary_format<float>::sign_index() {
   return 31;
 }
@@ -556,6 +624,7 @@ template <>
 inline constexpr int binary_format<double>::max_exponent_fast_path() {
   return 22;
 }
+
 template <>
 inline constexpr int binary_format<float>::max_exponent_fast_path() {
   return 10;
@@ -565,6 +634,261 @@ template <>
 inline constexpr uint64_t binary_format<double>::max_mantissa_fast_path() {
   return uint64_t(2) << mantissa_explicit_bits();
 }
+
+template <>
+inline constexpr uint64_t binary_format<float>::max_mantissa_fast_path() {
+  return uint64_t(2) << mantissa_explicit_bits();
+}
+
+// credit: Jakub Jelínek
+#ifdef __STDCPP_FLOAT16_T__
+template <typename U> struct binary_format_lookup_tables<std::float16_t, U> {
+  static constexpr std::float16_t powers_of_ten[] = {1e0f16, 1e1f16, 1e2f16,
+                                                     1e3f16, 1e4f16};
+
+  // Largest integer value v so that (5**index * v) <= 1<<11.
+  // 0x800 == 1<<11
+  static constexpr uint64_t max_mantissa[] = {0x800,
+                                              0x800 / 5,
+                                              0x800 / (5 * 5),
+                                              0x800 / (5 * 5 * 5),
+                                              0x800 / (5 * 5 * 5 * 5),
+                                              0x800 / (constant_55555)};
+};
+
+#if FASTFLOAT_DETAIL_MUST_DEFINE_CONSTEXPR_VARIABLE
+
+template <typename U>
+constexpr std::float16_t
+    binary_format_lookup_tables<std::float16_t, U>::powers_of_ten[];
+
+template <typename U>
+constexpr uint64_t
+    binary_format_lookup_tables<std::float16_t, U>::max_mantissa[];
+
+#endif
+
+template <>
+inline constexpr std::float16_t
+binary_format<std::float16_t>::exact_power_of_ten(int64_t power) {
+  // Work around clang bug https://godbolt.org/z/zedh7rrhc
+  return (void)powers_of_ten[0], powers_of_ten[power];
+}
+
+template <>
+inline constexpr binary_format<std::float16_t>::equiv_uint
+binary_format<std::float16_t>::exponent_mask() {
+  return 0x7C00;
+}
+
+template <>
+inline constexpr binary_format<std::float16_t>::equiv_uint
+binary_format<std::float16_t>::mantissa_mask() {
+  return 0x03FF;
+}
+
+template <>
+inline constexpr binary_format<std::float16_t>::equiv_uint
+binary_format<std::float16_t>::hidden_bit_mask() {
+  return 0x0400;
+}
+
+template <>
+inline constexpr int binary_format<std::float16_t>::max_exponent_fast_path() {
+  return 4;
+}
+
+template <>
+inline constexpr int binary_format<std::float16_t>::mantissa_explicit_bits() {
+  return 10;
+}
+
+template <>
+inline constexpr uint64_t
+binary_format<std::float16_t>::max_mantissa_fast_path() {
+  return uint64_t(2) << mantissa_explicit_bits();
+}
+
+template <>
+inline constexpr uint64_t
+binary_format<std::float16_t>::max_mantissa_fast_path(int64_t power) {
+  // caller is responsible to ensure that
+  // power >= 0 && power <= 4
+  //
+  // Work around clang bug https://godbolt.org/z/zedh7rrhc
+  return (void)max_mantissa[0], max_mantissa[power];
+}
+
+template <>
+inline constexpr int binary_format<std::float16_t>::min_exponent_fast_path() {
+  return 0;
+}
+
+template <>
+inline constexpr int
+binary_format<std::float16_t>::max_exponent_round_to_even() {
+  return 5;
+}
+
+template <>
+inline constexpr int
+binary_format<std::float16_t>::min_exponent_round_to_even() {
+  return -22;
+}
+
+template <>
+inline constexpr int binary_format<std::float16_t>::minimum_exponent() {
+  return -15;
+}
+
+template <>
+inline constexpr int binary_format<std::float16_t>::infinite_power() {
+  return 0x1F;
+}
+
+template <> inline constexpr int binary_format<std::float16_t>::sign_index() {
+  return 15;
+}
+
+template <>
+inline constexpr int binary_format<std::float16_t>::largest_power_of_ten() {
+  return 4;
+}
+
+template <>
+inline constexpr int binary_format<std::float16_t>::smallest_power_of_ten() {
+  return -27;
+}
+
+template <>
+inline constexpr size_t binary_format<std::float16_t>::max_digits() {
+  return 22;
+}
+#endif // __STDCPP_FLOAT16_T__
+
+// credit: Jakub Jelínek
+#ifdef __STDCPP_BFLOAT16_T__
+template <typename U> struct binary_format_lookup_tables<std::bfloat16_t, U> {
+  static constexpr std::bfloat16_t powers_of_ten[] = {1e0bf16, 1e1bf16, 1e2bf16,
+                                                      1e3bf16};
+
+  // Largest integer value v so that (5**index * v) <= 1<<8.
+  // 0x100 == 1<<8
+  static constexpr uint64_t max_mantissa[] = {0x100, 0x100 / 5, 0x100 / (5 * 5),
+                                              0x100 / (5 * 5 * 5),
+                                              0x100 / (5 * 5 * 5 * 5)};
+};
+
+#if FASTFLOAT_DETAIL_MUST_DEFINE_CONSTEXPR_VARIABLE
+
+template <typename U>
+constexpr std::bfloat16_t
+    binary_format_lookup_tables<std::bfloat16_t, U>::powers_of_ten[];
+
+template <typename U>
+constexpr uint64_t
+    binary_format_lookup_tables<std::bfloat16_t, U>::max_mantissa[];
+
+#endif
+
+template <>
+inline constexpr std::bfloat16_t
+binary_format<std::bfloat16_t>::exact_power_of_ten(int64_t power) {
+  // Work around clang bug https://godbolt.org/z/zedh7rrhc
+  return (void)powers_of_ten[0], powers_of_ten[power];
+}
+
+template <>
+inline constexpr int binary_format<std::bfloat16_t>::max_exponent_fast_path() {
+  return 3;
+}
+
+template <>
+inline constexpr binary_format<std::bfloat16_t>::equiv_uint
+binary_format<std::bfloat16_t>::exponent_mask() {
+  return 0x7F80;
+}
+
+template <>
+inline constexpr binary_format<std::bfloat16_t>::equiv_uint
+binary_format<std::bfloat16_t>::mantissa_mask() {
+  return 0x007F;
+}
+
+template <>
+inline constexpr binary_format<std::bfloat16_t>::equiv_uint
+binary_format<std::bfloat16_t>::hidden_bit_mask() {
+  return 0x0080;
+}
+
+template <>
+inline constexpr int binary_format<std::bfloat16_t>::mantissa_explicit_bits() {
+  return 7;
+}
+
+template <>
+inline constexpr uint64_t
+binary_format<std::bfloat16_t>::max_mantissa_fast_path() {
+  return uint64_t(2) << mantissa_explicit_bits();
+}
+
+template <>
+inline constexpr uint64_t
+binary_format<std::bfloat16_t>::max_mantissa_fast_path(int64_t power) {
+  // caller is responsible to ensure that
+  // power >= 0 && power <= 3
+  //
+  // Work around clang bug https://godbolt.org/z/zedh7rrhc
+  return (void)max_mantissa[0], max_mantissa[power];
+}
+
+template <>
+inline constexpr int binary_format<std::bfloat16_t>::min_exponent_fast_path() {
+  return 0;
+}
+
+template <>
+inline constexpr int
+binary_format<std::bfloat16_t>::max_exponent_round_to_even() {
+  return 3;
+}
+
+template <>
+inline constexpr int
+binary_format<std::bfloat16_t>::min_exponent_round_to_even() {
+  return -24;
+}
+
+template <>
+inline constexpr int binary_format<std::bfloat16_t>::minimum_exponent() {
+  return -127;
+}
+
+template <>
+inline constexpr int binary_format<std::bfloat16_t>::infinite_power() {
+  return 0xFF;
+}
+
+template <> inline constexpr int binary_format<std::bfloat16_t>::sign_index() {
+  return 15;
+}
+
+template <>
+inline constexpr int binary_format<std::bfloat16_t>::largest_power_of_ten() {
+  return 38;
+}
+
+template <>
+inline constexpr int binary_format<std::bfloat16_t>::smallest_power_of_ten() {
+  return -60;
+}
+
+template <>
+inline constexpr size_t binary_format<std::bfloat16_t>::max_digits() {
+  return 98;
+}
+#endif // __STDCPP_BFLOAT16_T__
+
 template <>
 inline constexpr uint64_t
 binary_format<double>::max_mantissa_fast_path(int64_t power) {
@@ -574,10 +898,7 @@ binary_format<double>::max_mantissa_fast_path(int64_t power) {
   // Work around clang bug https://godbolt.org/z/zedh7rrhc
   return (void)max_mantissa[0], max_mantissa[power];
 }
-template <>
-inline constexpr uint64_t binary_format<float>::max_mantissa_fast_path() {
-  return uint64_t(2) << mantissa_explicit_bits();
-}
+
 template <>
 inline constexpr uint64_t
 binary_format<float>::max_mantissa_fast_path(int64_t power) {
@@ -594,6 +915,7 @@ binary_format<double>::exact_power_of_ten(int64_t power) {
   // Work around clang bug https://godbolt.org/z/zedh7rrhc
   return (void)powers_of_ten[0], powers_of_ten[power];
 }
+
 template <>
 inline constexpr float binary_format<float>::exact_power_of_ten(int64_t power) {
   // Work around clang bug https://godbolt.org/z/zedh7rrhc
@@ -603,6 +925,7 @@ inline constexpr float binary_format<float>::exact_power_of_ten(int64_t power) {
 template <> inline constexpr int binary_format<double>::largest_power_of_ten() {
   return 308;
 }
+
 template <> inline constexpr int binary_format<float>::largest_power_of_ten() {
   return 38;
 }
@@ -611,6 +934,7 @@ template <>
 inline constexpr int binary_format<double>::smallest_power_of_ten() {
   return -342;
 }
+
 template <> inline constexpr int binary_format<float>::smallest_power_of_ten() {
   return -64;
 }
@@ -618,6 +942,7 @@ template <> inline constexpr int binary_format<float>::smallest_power_of_ten() {
 template <> inline constexpr size_t binary_format<double>::max_digits() {
   return 769;
 }
+
 template <> inline constexpr size_t binary_format<float>::max_digits() {
   return 114;
 }
@@ -627,6 +952,7 @@ inline constexpr binary_format<float>::equiv_uint
 binary_format<float>::exponent_mask() {
   return 0x7F800000;
 }
+
 template <>
 inline constexpr binary_format<double>::equiv_uint
 binary_format<double>::exponent_mask() {
@@ -638,6 +964,7 @@ inline constexpr binary_format<float>::equiv_uint
 binary_format<float>::mantissa_mask() {
   return 0x007FFFFF;
 }
+
 template <>
 inline constexpr binary_format<double>::equiv_uint
 binary_format<double>::mantissa_mask() {
@@ -649,6 +976,7 @@ inline constexpr binary_format<float>::equiv_uint
 binary_format<float>::hidden_bit_mask() {
   return 0x00800000;
 }
+
 template <>
 inline constexpr binary_format<double>::equiv_uint
 binary_format<double>::hidden_bit_mask() {
@@ -658,11 +986,12 @@ binary_format<double>::hidden_bit_mask() {
 template <typename T>
 fastfloat_really_inline FASTFLOAT_CONSTEXPR20 void
 to_float(bool negative, adjusted_mantissa am, T &value) {
-  using fastfloat_uint = typename binary_format<T>::equiv_uint;
-  fastfloat_uint word = (fastfloat_uint)am.mantissa;
-  word |= fastfloat_uint(am.power2)
-          << binary_format<T>::mantissa_explicit_bits();
-  word |= fastfloat_uint(negative) << binary_format<T>::sign_index();
+  using equiv_uint = equiv_uint_t<T>;
+  equiv_uint word = equiv_uint(am.mantissa);
+  word = equiv_uint(word | equiv_uint(am.power2)
+                               << binary_format<T>::mantissa_explicit_bits());
+  word =
+      equiv_uint(word | equiv_uint(negative) << binary_format<T>::sign_index());
 #if FASTFLOAT_HAS_BIT_CAST
   value = std::bit_cast<T>(word);
 #else
@@ -670,7 +999,6 @@ to_float(bool negative, adjusted_mantissa am, T &value) {
 #endif
 }
 
-#ifdef FASTFLOAT_SKIP_WHITE_SPACE // disabled by default
 template <typename = void> struct space_lut {
   static constexpr bool value[] = {
       0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
@@ -692,8 +1020,9 @@ template <typename T> constexpr bool space_lut<T>::value[];
 
 #endif
 
-inline constexpr bool is_space(uint8_t c) { return space_lut<>::value[c]; }
-#endif
+template <typename UC> constexpr bool is_space(UC c) {
+  return c < 256 && space_lut<>::value[uint8_t(c)];
+}
 
 template <typename UC> static constexpr uint64_t int_cmp_zeros() {
   static_assert((sizeof(UC) == 1) || (sizeof(UC) == 2) || (sizeof(UC) == 4),
@@ -704,34 +1033,53 @@ template <typename UC> static constexpr uint64_t int_cmp_zeros() {
                 uint64_t(UC('0')) << 16 | UC('0'))
              : (uint64_t(UC('0')) << 32 | UC('0'));
 }
+
 template <typename UC> static constexpr int int_cmp_len() {
   return sizeof(uint64_t) / sizeof(UC);
 }
-template <typename UC> static constexpr UC const *str_const_nan() {
-  return nullptr;
-}
+
+template <typename UC> constexpr UC const *str_const_nan();
+
 template <> constexpr char const *str_const_nan<char>() { return "nan"; }
+
 template <> constexpr wchar_t const *str_const_nan<wchar_t>() { return L"nan"; }
+
 template <> constexpr char16_t const *str_const_nan<char16_t>() {
   return u"nan";
 }
+
 template <> constexpr char32_t const *str_const_nan<char32_t>() {
   return U"nan";
 }
-template <typename UC> static constexpr UC const *str_const_inf() {
-  return nullptr;
+
+#ifdef __cpp_char8_t
+template <> constexpr char8_t const *str_const_nan<char8_t>() {
+  return u8"nan";
 }
+#endif
+
+template <typename UC> constexpr UC const *str_const_inf();
+
 template <> constexpr char const *str_const_inf<char>() { return "infinity"; }
+
 template <> constexpr wchar_t const *str_const_inf<wchar_t>() {
   return L"infinity";
 }
+
 template <> constexpr char16_t const *str_const_inf<char16_t>() {
   return u"infinity";
 }
+
 template <> constexpr char32_t const *str_const_inf<char32_t>() {
   return U"infinity";
 }
 
+#ifdef __cpp_char8_t
+template <> constexpr char8_t const *str_const_inf<char8_t>() {
+  return u8"infinity";
+}
+#endif
+
 template <typename = void> struct int_luts {
   static constexpr uint8_t chdigit[] = {
       255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
@@ -784,7 +1132,12 @@ template <typename T> constexpr uint64_t int_luts<T>::min_safe_u64[];
 
 template <typename UC>
 fastfloat_really_inline constexpr uint8_t ch_to_digit(UC c) {
-  return int_luts<>::chdigit[static_cast<unsigned char>(c)];
+  // wchar_t and char can be signed, so we need to be careful.
+  using UnsignedUC = typename std::make_unsigned<UC>::type;
+  return int_luts<>::chdigit[static_cast<unsigned char>(
+      static_cast<UnsignedUC>(c) &
+      static_cast<UnsignedUC>(
+          -((static_cast<UnsignedUC>(c) & ~0xFFull) == 0)))];
 }
 
 fastfloat_really_inline constexpr size_t max_digits_u64(int base) {
@@ -797,6 +1150,107 @@ fastfloat_really_inline constexpr uint64_t min_safe_u64(int base) {
   return int_luts<>::min_safe_u64[base - 2];
 }
 
+static_assert(std::is_same<equiv_uint_t<double>, uint64_t>::value,
+              "equiv_uint should be uint64_t for double");
+static_assert(std::numeric_limits<double>::is_iec559,
+              "double must fulfill the requirements of IEC 559 (IEEE 754)");
+
+static_assert(std::is_same<equiv_uint_t<float>, uint32_t>::value,
+              "equiv_uint should be uint32_t for float");
+static_assert(std::numeric_limits<float>::is_iec559,
+              "float must fulfill the requirements of IEC 559 (IEEE 754)");
+
+#ifdef __STDCPP_FLOAT64_T__
+static_assert(std::is_same<equiv_uint_t<std::float64_t>, uint64_t>::value,
+              "equiv_uint should be uint64_t for std::float64_t");
+static_assert(
+    std::numeric_limits<std::float64_t>::is_iec559,
+    "std::float64_t must fulfill the requirements of IEC 559 (IEEE 754)");
+
+template <>
+struct binary_format<std::float64_t> : public binary_format<double> {};
+#endif // __STDCPP_FLOAT64_T__
+
+#ifdef __STDCPP_FLOAT32_T__
+static_assert(std::is_same<equiv_uint_t<std::float32_t>, uint32_t>::value,
+              "equiv_uint should be uint32_t for std::float32_t");
+static_assert(
+    std::numeric_limits<std::float32_t>::is_iec559,
+    "std::float32_t must fulfill the requirements of IEC 559 (IEEE 754)");
+
+template <>
+struct binary_format<std::float32_t> : public binary_format<float> {};
+#endif // __STDCPP_FLOAT32_T__
+
+#ifdef __STDCPP_FLOAT16_T__
+static_assert(
+    std::is_same<binary_format<std::float16_t>::equiv_uint, uint16_t>::value,
+    "equiv_uint should be uint16_t for std::float16_t");
+static_assert(
+    std::numeric_limits<std::float16_t>::is_iec559,
+    "std::float16_t must fulfill the requirements of IEC 559 (IEEE 754)");
+#endif // __STDCPP_FLOAT16_T__
+
+#ifdef __STDCPP_BFLOAT16_T__
+static_assert(
+    std::is_same<binary_format<std::bfloat16_t>::equiv_uint, uint16_t>::value,
+    "equiv_uint should be uint16_t for std::bfloat16_t");
+static_assert(
+    std::numeric_limits<std::bfloat16_t>::is_iec559,
+    "std::bfloat16_t must fulfill the requirements of IEC 559 (IEEE 754)");
+#endif // __STDCPP_BFLOAT16_T__
+
+constexpr chars_format operator~(chars_format rhs) noexcept {
+  using int_type = std::underlying_type<chars_format>::type;
+  return static_cast<chars_format>(~static_cast<int_type>(rhs));
+}
+
+constexpr chars_format operator&(chars_format lhs, chars_format rhs) noexcept {
+  using int_type = std::underlying_type<chars_format>::type;
+  return static_cast<chars_format>(static_cast<int_type>(lhs) &
+                                   static_cast<int_type>(rhs));
+}
+
+constexpr chars_format operator|(chars_format lhs, chars_format rhs) noexcept {
+  using int_type = std::underlying_type<chars_format>::type;
+  return static_cast<chars_format>(static_cast<int_type>(lhs) |
+                                   static_cast<int_type>(rhs));
+}
+
+constexpr chars_format operator^(chars_format lhs, chars_format rhs) noexcept {
+  using int_type = std::underlying_type<chars_format>::type;
+  return static_cast<chars_format>(static_cast<int_type>(lhs) ^
+                                   static_cast<int_type>(rhs));
+}
+
+fastfloat_really_inline FASTFLOAT_CONSTEXPR14 chars_format &
+operator&=(chars_format &lhs, chars_format rhs) noexcept {
+  return lhs = (lhs & rhs);
+}
+
+fastfloat_really_inline FASTFLOAT_CONSTEXPR14 chars_format &
+operator|=(chars_format &lhs, chars_format rhs) noexcept {
+  return lhs = (lhs | rhs);
+}
+
+fastfloat_really_inline FASTFLOAT_CONSTEXPR14 chars_format &
+operator^=(chars_format &lhs, chars_format rhs) noexcept {
+  return lhs = (lhs ^ rhs);
+}
+
+namespace detail {
+// adjust for deprecated feature macros
+constexpr chars_format adjust_for_feature_macros(chars_format fmt) {
+  return fmt
+#ifdef FASTFLOAT_ALLOWS_LEADING_PLUS
+         | chars_format::allow_leading_plus
+#endif
+#ifdef FASTFLOAT_SKIP_WHITE_SPACE
+         | chars_format::skip_white_space
+#endif
+      ;
+}
+} // namespace detail
 } // namespace fast_float
 
 #endif

include/fast_float/parse_number.h

@@ -10,6 +10,7 @@
 #include <cstring>
 #include <limits>
 #include <system_error>
+
 namespace fast_float {
 
 namespace detail {
@@ -19,24 +20,20 @@ namespace detail {
  * strings a null-free and fixed.
  **/
 template <typename T, typename UC>
-from_chars_result_t<UC> FASTFLOAT_CONSTEXPR14 parse_infnan(UC const *first,
-                                                           UC const *last,
-                                                           T &value) noexcept {
+from_chars_result_t<UC>
+    FASTFLOAT_CONSTEXPR14 parse_infnan(UC const *first, UC const *last,
+                                       T &value, chars_format fmt) noexcept {
   from_chars_result_t<UC> answer{};
   answer.ptr = first;
   answer.ec = std::errc(); // be optimistic
-  bool minusSign = false;
-  if (*first ==
-      UC('-')) { // assume first < last, so dereference without checks;
-                 // C++17 20.19.3.(7.1) explicitly forbids '+' here
-    minusSign = true;
+  // assume first < last, so dereference without checks;
+  bool const minusSign = (*first == UC('-'));
+  // C++17 20.19.3.(7.1) explicitly forbids '+' sign here
+  if ((*first == UC('-')) ||
+      (uint64_t(fmt & chars_format::allow_leading_plus) &&
+       (*first == UC('+')))) {
     ++first;
   }
-#ifdef FASTFLOAT_ALLOWS_LEADING_PLUS // disabled by default
-  if (*first == UC('+')) {
-    ++first;
-  }
-#endif
   if (last - first >= 3) {
     if (fastfloat_strncasecmp(first, str_const_nan<UC>(), 3)) {
       answer.ptr = (first += 3);
@@ -93,13 +90,13 @@ fastfloat_really_inline bool rounds_to_nearest() noexcept {
   // However, it is expected to be much faster than the fegetround()
   // function call.
   //
-  // The volatile keywoard prevents the compiler from computing the function
+  // The volatile keyword prevents the compiler from computing the function
   // at compile-time.
   // There might be other ways to prevent compile-time optimizations (e.g.,
   // asm). The value does not need to be std::numeric_limits<float>::min(), any
   // small value so that 1 + x should round to 1 would do (after accounting for
   // excess precision, as in 387 instructions).
-  static volatile float fmin = std::numeric_limits<float>::min();
+  static float volatile fmin = std::numeric_limits<float>::min();
   float fmini = fmin; // we copy it so that it gets loaded at most once.
 //
 // Explanation:
@@ -149,7 +146,7 @@ template <typename T> struct from_chars_caller {
   }
 };
 
-#if __STDCPP_FLOAT32_T__ == 1
+#ifdef __STDCPP_FLOAT32_T__
 template <> struct from_chars_caller<std::float32_t> {
   template <typename UC>
   FASTFLOAT_CONSTEXPR20 static from_chars_result_t<UC>
@@ -166,7 +163,7 @@ template <> struct from_chars_caller<std::float32_t> {
 };
 #endif
 
-#if __STDCPP_FLOAT64_T__ == 1
+#ifdef __STDCPP_FLOAT64_T__
 template <> struct from_chars_caller<std::float64_t> {
   template <typename UC>
   FASTFLOAT_CONSTEXPR20 static from_chars_result_t<UC>
@@ -191,32 +188,17 @@ from_chars(UC const *first, UC const *last, T &value,
                                     parse_options_t<UC>(fmt));
 }
 
-/**
- * This function overload takes parsed_number_string_t structure that is created
- * and populated either by from_chars_advanced function taking chars range and
- * parsing options or other parsing custom function implemented by user.
- */
-template <typename T, typename UC>
-FASTFLOAT_CONSTEXPR20 from_chars_result_t<UC>
-from_chars_advanced(parsed_number_string_t<UC> &pns, T &value) noexcept {
-
-  static_assert(is_supported_float_type<T>(),
-                "only some floating-point types are supported");
-  static_assert(is_supported_char_type<UC>(),
-                "only char, wchar_t, char16_t and char32_t are supported");
-
-  from_chars_result_t<UC> answer;
-
-  answer.ec = std::errc(); // be optimistic
-  answer.ptr = pns.lastmatch;
+template <typename T>
+fastfloat_really_inline FASTFLOAT_CONSTEXPR20 bool
+clinger_fast_path_impl(uint64_t mantissa, int64_t exponent, bool is_negative,
+                       T &value) noexcept {
   // The implementation of the Clinger's fast path is convoluted because
   // we want round-to-nearest in all cases, irrespective of the rounding mode
   // selected on the thread.
   // We proceed optimistically, assuming that detail::rounds_to_nearest()
   // returns true.
-  if (binary_format<T>::min_exponent_fast_path() <= pns.exponent &&
-      pns.exponent <= binary_format<T>::max_exponent_fast_path() &&
-      !pns.too_many_digits) {
+  if (binary_format<T>::min_exponent_fast_path() <= exponent &&
+      exponent <= binary_format<T>::max_exponent_fast_path()) {
     // Unfortunately, the conventional Clinger's fast path is only possible
     // when the system rounds to the nearest float.
     //
@@ -227,41 +209,64 @@ from_chars_advanced(parsed_number_string_t<UC> &pns, T &value) noexcept {
     if (!cpp20_and_in_constexpr() && detail::rounds_to_nearest()) {
       // We have that fegetround() == FE_TONEAREST.
       // Next is Clinger's fast path.
-      if (pns.mantissa <= binary_format<T>::max_mantissa_fast_path()) {
-        value = T(pns.mantissa);
-        if (pns.exponent < 0) {
-          value = value / binary_format<T>::exact_power_of_ten(-pns.exponent);
+      if (mantissa <= binary_format<T>::max_mantissa_fast_path()) {
+        value = T(mantissa);
+        if (exponent < 0) {
+          value = value / binary_format<T>::exact_power_of_ten(-exponent);
         } else {
-          value = value * binary_format<T>::exact_power_of_ten(pns.exponent);
+          value = value * binary_format<T>::exact_power_of_ten(exponent);
         }
-        if (pns.negative) {
+        if (is_negative) {
           value = -value;
         }
-        return answer;
+        return true;
       }
     } else {
       // We do not have that fegetround() == FE_TONEAREST.
       // Next is a modified Clinger's fast path, inspired by Jakub Jelínek's
       // proposal
-      if (pns.exponent >= 0 &&
-          pns.mantissa <=
-              binary_format<T>::max_mantissa_fast_path(pns.exponent)) {
+      if (exponent >= 0 &&
+          mantissa <= binary_format<T>::max_mantissa_fast_path(exponent)) {
 #if defined(__clang__) || defined(FASTFLOAT_32BIT)
         // Clang may map 0 to -0.0 when fegetround() == FE_DOWNWARD
-        if (pns.mantissa == 0) {
-          value = pns.negative ? T(-0.) : T(0.);
-          return answer;
+        if (mantissa == 0) {
+          value = is_negative ? T(-0.) : T(0.);
+          return true;
         }
 #endif
-        value = T(pns.mantissa) *
-                binary_format<T>::exact_power_of_ten(pns.exponent);
-        if (pns.negative) {
+        value = T(mantissa) * binary_format<T>::exact_power_of_ten(exponent);
+        if (is_negative) {
           value = -value;
         }
-        return answer;
+        return true;
       }
     }
   }
+  return false;
+}
+
+/**
+ * This function overload takes parsed_number_string_t structure that is created
+ * and populated either by from_chars_advanced function taking chars range and
+ * parsing options or other parsing custom function implemented by user.
+ */
+template <typename T, typename UC>
+FASTFLOAT_CONSTEXPR20 from_chars_result_t<UC>
+from_chars_advanced(parsed_number_string_t<UC> &pns, T &value) noexcept {
+  static_assert(is_supported_float_type<T>::value,
+                "only some floating-point types are supported");
+  static_assert(is_supported_char_type<UC>::value,
+                "only char, wchar_t, char16_t and char32_t are supported");
+
+  from_chars_result_t<UC> answer;
+
+  answer.ec = std::errc(); // be optimistic
+  answer.ptr = pns.lastmatch;
+
+  if (!pns.too_many_digits &&
+      clinger_fast_path_impl(pns.mantissa, pns.exponent, pns.negative, value))
+    return answer;
+
   adjusted_mantissa am =
       compute_float<binary_format<T>>(pns.exponent, pns.mantissa);
   if (pns.too_many_digits && am.power2 >= 0) {
@@ -286,34 +291,38 @@ from_chars_advanced(parsed_number_string_t<UC> &pns, T &value) noexcept {
 
 template <typename T, typename UC>
 FASTFLOAT_CONSTEXPR20 from_chars_result_t<UC>
-from_chars_advanced(UC const *first, UC const *last, T &value,
-                    parse_options_t<UC> options) noexcept {
+from_chars_float_advanced(UC const *first, UC const *last, T &value,
+                          parse_options_t<UC> options) noexcept {
 
-  static_assert(is_supported_float_type<T>(),
+  static_assert(is_supported_float_type<T>::value,
                 "only some floating-point types are supported");
-  static_assert(is_supported_char_type<UC>(),
+  static_assert(is_supported_char_type<UC>::value,
                 "only char, wchar_t, char16_t and char32_t are supported");
 
+  chars_format const fmt = detail::adjust_for_feature_macros(options.format);
+
   from_chars_result_t<UC> answer;
-#ifdef FASTFLOAT_SKIP_WHITE_SPACE // disabled by default
-  while ((first != last) && fast_float::is_space(uint8_t(*first))) {
-    first++;
+  if (uint64_t(fmt & chars_format::skip_white_space)) {
+    while ((first != last) && fast_float::is_space(*first)) {
+      first++;
+    }
   }
-#endif
   if (first == last) {
     answer.ec = std::errc::invalid_argument;
     answer.ptr = first;
     return answer;
   }
   parsed_number_string_t<UC> pns =
-      parse_number_string<UC>(first, last, options);
+      uint64_t(fmt & detail::basic_json_fmt)
+          ? parse_number_string<true, UC>(first, last, options)
+          : parse_number_string<false, UC>(first, last, options);
   if (!pns.valid) {
-    if (options.format & chars_format::no_infnan) {
+    if (uint64_t(fmt & chars_format::no_infnan)) {
       answer.ec = std::errc::invalid_argument;
       answer.ptr = first;
       return answer;
     } else {
-      return detail::parse_infnan(first, last, value);
+      return detail::parse_infnan(first, last, value, fmt);
     }
   }
 
@@ -324,21 +333,153 @@ from_chars_advanced(UC const *first, UC const *last, T &value,
 template <typename T, typename UC, typename>
 FASTFLOAT_CONSTEXPR20 from_chars_result_t<UC>
 from_chars(UC const *first, UC const *last, T &value, int base) noexcept {
-  static_assert(is_supported_char_type<UC>(),
+
+  static_assert(is_supported_integer_type<T>::value,
+                "only integer types are supported");
+  static_assert(is_supported_char_type<UC>::value,
                 "only char, wchar_t, char16_t and char32_t are supported");
 
+  parse_options_t<UC> options;
+  options.base = base;
+  return from_chars_advanced(first, last, value, options);
+}
+
+template <typename T>
+FASTFLOAT_CONSTEXPR20
+    typename std::enable_if<is_supported_float_type<T>::value, T>::type
+    integer_times_pow10(uint64_t mantissa, int decimal_exponent) noexcept {
+  T value;
+  if (clinger_fast_path_impl(mantissa, decimal_exponent, false, value))
+    return value;
+
+  adjusted_mantissa am =
+      compute_float<binary_format<T>>(decimal_exponent, mantissa);
+  to_float(false, am, value);
+  return value;
+}
+
+template <typename T>
+FASTFLOAT_CONSTEXPR20
+    typename std::enable_if<is_supported_float_type<T>::value, T>::type
+    integer_times_pow10(int64_t mantissa, int decimal_exponent) noexcept {
+  const bool is_negative = mantissa < 0;
+  const uint64_t m = static_cast<uint64_t>(is_negative ? -mantissa : mantissa);
+
+  T value;
+  if (clinger_fast_path_impl(m, decimal_exponent, is_negative, value))
+    return value;
+
+  adjusted_mantissa am = compute_float<binary_format<T>>(decimal_exponent, m);
+  to_float(is_negative, am, value);
+  return value;
+}
+
+FASTFLOAT_CONSTEXPR20 inline double
+integer_times_pow10(uint64_t mantissa, int decimal_exponent) noexcept {
+  return integer_times_pow10<double>(mantissa, decimal_exponent);
+}
+
+FASTFLOAT_CONSTEXPR20 inline double
+integer_times_pow10(int64_t mantissa, int decimal_exponent) noexcept {
+  return integer_times_pow10<double>(mantissa, decimal_exponent);
+}
+
+// the following overloads are here to avoid surprising ambiguity for int,
+// unsigned, etc.
+template <typename T, typename Int>
+FASTFLOAT_CONSTEXPR20
+    typename std::enable_if<is_supported_float_type<T>::value &&
+                                std::is_integral<Int>::value &&
+                                !std::is_signed<Int>::value,
+                            T>::type
+    integer_times_pow10(Int mantissa, int decimal_exponent) noexcept {
+  return integer_times_pow10<T>(static_cast<uint64_t>(mantissa),
+                                decimal_exponent);
+}
+
+template <typename T, typename Int>
+FASTFLOAT_CONSTEXPR20
+    typename std::enable_if<is_supported_float_type<T>::value &&
+                                std::is_integral<Int>::value &&
+                                std::is_signed<Int>::value,
+                            T>::type
+    integer_times_pow10(Int mantissa, int decimal_exponent) noexcept {
+  return integer_times_pow10<T>(static_cast<int64_t>(mantissa),
+                                decimal_exponent);
+}
+
+template <typename Int>
+FASTFLOAT_CONSTEXPR20 typename std::enable_if<
+    std::is_integral<Int>::value && !std::is_signed<Int>::value, double>::type
+integer_times_pow10(Int mantissa, int decimal_exponent) noexcept {
+  return integer_times_pow10(static_cast<uint64_t>(mantissa), decimal_exponent);
+}
+
+template <typename Int>
+FASTFLOAT_CONSTEXPR20 typename std::enable_if<
+    std::is_integral<Int>::value && std::is_signed<Int>::value, double>::type
+integer_times_pow10(Int mantissa, int decimal_exponent) noexcept {
+  return integer_times_pow10(static_cast<int64_t>(mantissa), decimal_exponent);
+}
+
+template <typename T, typename UC>
+FASTFLOAT_CONSTEXPR20 from_chars_result_t<UC>
+from_chars_int_advanced(UC const *first, UC const *last, T &value,
+                        parse_options_t<UC> options) noexcept {
+
+  static_assert(is_supported_integer_type<T>::value,
+                "only integer types are supported");
+  static_assert(is_supported_char_type<UC>::value,
+                "only char, wchar_t, char16_t and char32_t are supported");
+
+  chars_format const fmt = detail::adjust_for_feature_macros(options.format);
+  int const base = options.base;
+
   from_chars_result_t<UC> answer;
-#ifdef FASTFLOAT_SKIP_WHITE_SPACE // disabled by default
-  while ((first != last) && fast_float::is_space(uint8_t(*first))) {
-    first++;
+  if (uint64_t(fmt & chars_format::skip_white_space)) {
+    while ((first != last) && fast_float::is_space(*first)) {
+      first++;
+    }
   }
-#endif
   if (first == last || base < 2 || base > 36) {
     answer.ec = std::errc::invalid_argument;
     answer.ptr = first;
     return answer;
   }
-  return parse_int_string(first, last, value, base);
+
+  return parse_int_string(first, last, value, options);
+}
+
+template <size_t TypeIx> struct from_chars_advanced_caller {
+  static_assert(TypeIx > 0, "unsupported type");
+};
+
+template <> struct from_chars_advanced_caller<1> {
+  template <typename T, typename UC>
+  FASTFLOAT_CONSTEXPR20 static from_chars_result_t<UC>
+  call(UC const *first, UC const *last, T &value,
+       parse_options_t<UC> options) noexcept {
+    return from_chars_float_advanced(first, last, value, options);
+  }
+};
+
+template <> struct from_chars_advanced_caller<2> {
+  template <typename T, typename UC>
+  FASTFLOAT_CONSTEXPR20 static from_chars_result_t<UC>
+  call(UC const *first, UC const *last, T &value,
+       parse_options_t<UC> options) noexcept {
+    return from_chars_int_advanced(first, last, value, options);
+  }
+};
+
+template <typename T, typename UC>
+FASTFLOAT_CONSTEXPR20 from_chars_result_t<UC>
+from_chars_advanced(UC const *first, UC const *last, T &value,
+                    parse_options_t<UC> options) noexcept {
+  return from_chars_advanced_caller<
+      size_t(is_supported_float_type<T>::value) +
+      2 * size_t(is_supported_integer_type<T>::value)>::call(first, last, value,
+                                                             options);
 }
 
 } // namespace fast_float

script/amalgamate.py

@@ -1,97 +1,122 @@
 # text parts
-processed_files = { }
+processed_files = {}
 
 # authors
-for filename in ['AUTHORS', 'CONTRIBUTORS']:
-  with open(filename, encoding='utf8') as f:
-    text = ''
-    for line in f:
-      if filename == 'AUTHORS':
-        text += '// fast_float by ' + line
-      if filename == 'CONTRIBUTORS':
-        text += '// with contributions from ' + line
-    processed_files[filename] = text + '//\n//\n'
+for filename in ["AUTHORS", "CONTRIBUTORS"]:
+    with open(filename, encoding="utf8") as f:
+        text = ""
+        for line in f:
+            if filename == "AUTHORS":
+                text += "// fast_float by " + line
+            if filename == "CONTRIBUTORS":
+                text += "// with contributions from " + line
+        processed_files[filename] = text + "//\n//\n"
 
 # licenses
-for filename in ['LICENSE-MIT', 'LICENSE-APACHE', 'LICENSE-BOOST']:
-  lines = []
-  with open(filename, encoding='utf8') as f:
-    lines = f.readlines()
+for filename in ["LICENSE-MIT", "LICENSE-APACHE", "LICENSE-BOOST"]:
+    lines = []
+    with open(filename, encoding="utf8") as f:
+        lines = f.readlines()
 
-  # Retrieve subset required for inclusion in source
-  if filename == 'LICENSE-APACHE':
-    lines = [
-      '   Copyright 2021 The fast_float authors\n',
-      *lines[179:-1]
-    ]
+    # Retrieve subset required for inclusion in source
+    if filename == "LICENSE-APACHE":
+        lines = ["   Copyright 2021 The fast_float authors\n", *lines[179:-1]]
 
-  text = ''
-  for line in lines:
-    text += '//    ' + line.strip() + '\n'
-  processed_files[filename] = text
+    text = ""
+    for line in lines:
+        line = line.strip()
+        if len(line):
+            line = "    " + line
+        text += "//" + line + "\n"
+    processed_files[filename] = text
 
 # code
-for filename in [ 'constexpr_feature_detect.h', 'float_common.h', 'fast_float.h', 'ascii_number.h',
-                  'fast_table.h', 'decimal_to_binary.h', 'bigint.h', 'digit_comparison.h', 'parse_number.h']:
-  with open('include/fast_float/' + filename, encoding='utf8') as f:
-    text = ''
-    for line in f:
-      if line.startswith('#include "'): continue
-      text += line
-    processed_files[filename] = '\n' + text
+for filename in [
+    "constexpr_feature_detect.h",
+    "float_common.h",
+    "fast_float.h",
+    "ascii_number.h",
+    "fast_table.h",
+    "decimal_to_binary.h",
+    "bigint.h",
+    "digit_comparison.h",
+    "parse_number.h",
+]:
+    with open("include/fast_float/" + filename, encoding="utf8") as f:
+        text = ""
+        for line in f:
+            if line.startswith('#include "'):
+                continue
+            text += line
+        processed_files[filename] = "\n" + text
 
 # command line
 import argparse
 
-parser = argparse.ArgumentParser(description='Amalgamate fast_float.')
-parser.add_argument('--license', default='TRIPLE', choices=['DUAL', 'TRIPLE', 'MIT', 'APACHE', 'BOOST'], help='choose license')
-parser.add_argument('--output', default='', help='output file (stdout if none')
+parser = argparse.ArgumentParser(description="Amalgamate fast_float.")
+parser.add_argument(
+    "--license",
+    default="TRIPLE",
+    choices=["DUAL", "TRIPLE", "MIT", "APACHE", "BOOST"],
+    help="choose license",
+)
+parser.add_argument("--output", default="", help="output file (stdout if none")
 
 args = parser.parse_args()
 
+
 def license_content(license_arg):
-  result = []
-  if license_arg == 'TRIPLE':
-    result += [
-      '// Licensed under the Apache License, Version 2.0, or the\n',
-      '// MIT License or the Boost License. This file may not be copied,\n',
-      '// modified, or distributed except according to those terms.\n',
-      '//\n'
+    result = []
+    if license_arg == "TRIPLE":
+        result += [
+            "// Licensed under the Apache License, Version 2.0, or the\n",
+            "// MIT License or the Boost License. This file may not be copied,\n",
+            "// modified, or distributed except according to those terms.\n",
+            "//\n",
+        ]
+    if license_arg == "DUAL":
+        result += [
+            "// Licensed under the Apache License, Version 2.0, or the\n",
+            "// MIT License at your option. This file may not be copied,\n",
+            "// modified, or distributed except according to those terms.\n",
+            "//\n",
+        ]
+
+    if license_arg in ("DUAL", "TRIPLE", "MIT"):
+        result.append("// MIT License Notice\n//\n")
+        result.append(processed_files["LICENSE-MIT"])
+        result.append("//\n")
+    if license_arg in ("DUAL", "TRIPLE", "APACHE"):
+        result.append("// Apache License (Version 2.0) Notice\n//\n")
+        result.append(processed_files["LICENSE-APACHE"])
+        result.append("//\n")
+    if license_arg in ("TRIPLE", "BOOST"):
+        result.append("// BOOST License Notice\n//\n")
+        result.append(processed_files["LICENSE-BOOST"])
+        result.append("//\n")
+
+    return result
+
+
+text = "".join(
+    [
+        processed_files["AUTHORS"],
+        processed_files["CONTRIBUTORS"],
+        *license_content(args.license),
+        processed_files["constexpr_feature_detect.h"],
+        processed_files["float_common.h"],
+        processed_files["fast_float.h"],
+        processed_files["ascii_number.h"],
+        processed_files["fast_table.h"],
+        processed_files["decimal_to_binary.h"],
+        processed_files["bigint.h"],
+        processed_files["digit_comparison.h"],
+        processed_files["parse_number.h"],
     ]
-  if license_arg == 'DUAL':
-    result += [
-      '// Licensed under the Apache License, Version 2.0, or the\n',
-      '// MIT License at your option. This file may not be copied,\n',
-      '// modified, or distributed except according to those terms.\n',
-      '//\n'
-    ]
-
-  if license_arg in ('DUAL', 'TRIPLE', 'MIT'):
-    result.append('// MIT License Notice\n//\n')
-    result.append(processed_files['LICENSE-MIT'])
-    result.append('//\n')
-  if license_arg in ('DUAL', 'TRIPLE', 'APACHE'):
-    result.append('// Apache License (Version 2.0) Notice\n//\n')
-    result.append(processed_files['LICENSE-APACHE'])
-    result.append('//\n')
-  if license_arg in ('TRIPLE', 'BOOST'):
-    result.append('// BOOST License Notice\n//\n')
-    result.append(processed_files['LICENSE-BOOST'])
-    result.append('//\n')
-
-  return result
-
-text = ''.join([
-  processed_files['AUTHORS'], processed_files['CONTRIBUTORS'],
-  *license_content(args.license),
-  processed_files['constexpr_feature_detect.h'],
-  processed_files['float_common.h'], processed_files['fast_float.h'],
-  processed_files['ascii_number.h'], processed_files['fast_table.h'],
-  processed_files['decimal_to_binary.h'], processed_files['bigint.h'],
-  processed_files['digit_comparison.h'], processed_files['parse_number.h']])
+)
 
 if args.output:
-  with open(args.output, 'wt', encoding='utf8') as f:
-    f.write(text)
+    with open(args.output, "wt", encoding="utf8") as f:
+        f.write(text)
 else:
-  print(text)
+    print(text)

script/analysis.py

@@ -1,36 +1,38 @@
+import sys
 from math import floor
 
+
 def log2(x):
-   """returns ceil(log2(x)))"""
-   y = 0
-   while((1<<y) < x):
-     y = y + 1
-   return y
+    """returns ceil(log2(x)))"""
+    y = 0
+    while (1 << y) < x:
+        y = y + 1
+    return y
 
 
-for q in range(1,17+1):
-    d = 5**q
+for q in range(1, 17 + 1):
+    d = 5 ** q
     b = 127 + log2(d)
-    t = 2** b
-    c = t//d + 1
-    assert c < 2**128
-    assert c >= 2**127
-    K = 2**127
-    if(not(c * K * d<=( K + 1) * t)):
-      print(q)
-      top = floor(t/(c  * d - t))
-      sys.exit(-1)
+    t = 2 ** b
+    c = t // d + 1
+    assert c < 2 ** 128
+    assert c >= 2 ** 127
+    K = 2 ** 127
+    if not (c * K * d <= (K + 1) * t):
+        print(q)
+        top = floor(t / (c * d - t))
+        sys.exit(-1)
 
-for q in range(18, 344+1):
-    d = 5**q
-    b = 64 + 2*log2(d)
-    t = 2**b
-    c = t//d + 1
-    assert c > 2**(64 +log2(d))
-    K = 2**64
-    if(not(c * K * d<=( K + 1) * t)):
-      print(q)
-      top = floor(t/(c  * d - t))
-      sys.exit(-1)
+for q in range(18, 344 + 1):
+    d = 5 ** q
+    b = 64 + 2 * log2(d)
+    t = 2 ** b
+    c = t // d + 1
+    assert c > 2 ** (64 + log2(d))
+    K = 2 ** 64
+    if not (c * K * d <= (K + 1) * t):
+        print(q)
+        top = floor(t / (c * d - t))
+        sys.exit(-1)
 
-print("all good")
+print("all good")

script/mushtak_lemire.py

@@ -9,25 +9,25 @@ all_tqs = []
 # Appendix B of  Number parsing at a gigabyte per second.
 # Software: Practice and Experience 2021;51(8):1700–1727.
 for q in range(-342, -27):
-    power5 = 5**-q
+    power5 = 5 ** -q
     z = 0
     while (1 << z) < power5:
         z += 1
     b = 2 * z + 2 * 64
-    c = 2**b // power5 + 1
+    c = 2 ** b // power5 + 1
     while c >= (1 << 128):
         c //= 2
     all_tqs.append(c)
 for q in range(-27, 0):
-    power5 = 5**-q
+    power5 = 5 ** -q
     z = 0
     while (1 << z) < power5:
         z += 1
     b = z + 127
-    c = 2**b // power5 + 1
+    c = 2 ** b // power5 + 1
     all_tqs.append(c)
 for q in range(0, 308 + 1):
-    power5 = 5**q
+    power5 = 5 ** q
     while power5 < (1 << 127):
         power5 *= 2
     while power5 >= (1 << 128):
@@ -44,6 +44,7 @@ def continued_fraction(numer, denom):
         numer, denom = denom, rem
     return cf
 
+
 # Given a continued fraction [a0; a1, a2, ..., an], returns
 # all the convergents of that continued fraction
 # as pairs of the form (numer, denom), where numer/denom is
@@ -58,17 +59,22 @@ def convergents(cf):
         p_n = a_n * p_n_minus_1 + p_n_minus_2
         q_n = a_n * q_n_minus_1 + q_n_minus_2
         convergents.append((p_n, q_n))
-        p_n_minus_2, q_n_minus_2, p_n_minus_1, q_n_minus_1 = p_n_minus_1, q_n_minus_1, p_n, q_n
+        p_n_minus_2, q_n_minus_2, p_n_minus_1, q_n_minus_1 = (
+            p_n_minus_1,
+            q_n_minus_1,
+            p_n,
+            q_n,
+        )
     return convergents
 
 
 # Enumerate through all the convergents of T[q] / 2^137 with denominators < 2^64
 found_solution = False
 for j, tq in enumerate(all_tqs):
-    for _, w in convergents(continued_fraction(tq, 2**137)):
-        if w >= 2**64:
+    for _, w in convergents(continued_fraction(tq, 2 ** 137)):
+        if w >= 2 ** 64:
             break
-            if (tq*w) % 2**137 > 2**137 - 2**64:
+            if (tq * w) % 2 ** 137 > 2 ** 137 - 2 ** 64:
                 print(f"SOLUTION: q={j-342} T[q]={tq} w={w}")
                 found_solution = True
 if not found_solution:

script/release.py

@@ -8,116 +8,176 @@ import subprocess
 import io
 import os
 import fileinput
+
 if sys.version_info < (3, 0):
     sys.stdout.write("Sorry, requires Python 3.x or better\n")
     sys.exit(1)
 
+
 def colored(r, g, b, text):
-    return "\033[38;2;{};{};{}m{} \033[38;2;255;255;255m".format(r, g, b, text)
+    return f"\033[38;2;{r};{g};{b}m{text} \033[38;2;255;255;255m"
+
 
 def extractnumbers(s):
-    return tuple(map(int,re.findall(r"(\d+)\.(\d+)\.(\d+)",str(s))[0]))
+    return tuple(map(int, re.findall(r"(\d+)\.(\d+)\.(\d+)", str(s))[0]))
+
 
 def toversionstring(major, minor, rev):
-    return str(major)+"."+str(minor)+"."+str(rev)
+    return f"{major}.{minor}.{rev}"
+
 
-def topaddedversionstring(major, minor, rev):
-    return str(major)+str(minor).zfill(3)+str(rev).zfill(3)
 print("Calling git rev-parse --abbrev-ref HEAD")
-pipe = subprocess.Popen(["git", "rev-parse", "--abbrev-ref", "HEAD"], stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
+pipe = subprocess.Popen(
+    ["git", "rev-parse", "--abbrev-ref", "HEAD"],
+    stdout=subprocess.PIPE,
+    stderr=subprocess.STDOUT,
+)
 branchresult = pipe.communicate()[0].decode().strip()
 
-if(branchresult != "main"):
-    print(colored(255, 0, 0, "We recommend that you release on main, you are on '"+branchresult+"'"))
+if branchresult != "main":
+    print(
+        colored(
+            255,
+            0,
+            0,
+            f"We recommend that you release on main, you are on '{branchresult}'",
+        )
+    )
 
 ret = subprocess.call(["git", "remote", "update"])
 
-if(ret != 0):
+if ret != 0:
     sys.exit(ret)
 print("Calling git log HEAD.. --oneline")
-pipe = subprocess.Popen(["git", "log", "HEAD..", "--oneline"], stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
+pipe = subprocess.Popen(
+    ["git", "log", "HEAD..", "--oneline"],
+    stdout=subprocess.PIPE,
+    stderr=subprocess.STDOUT,
+)
 uptodateresult = pipe.communicate()[0].decode().strip()
 
-if(len(uptodateresult) != 0):
+if len(uptodateresult) != 0:
     print(uptodateresult)
     sys.exit(-1)
 
-pipe = subprocess.Popen(["git", "rev-parse", "--show-toplevel"], stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
+pipe = subprocess.Popen(
+    ["git", "rev-parse", "--show-toplevel"],
+    stdout=subprocess.PIPE,
+    stderr=subprocess.STDOUT,
+)
 maindir = pipe.communicate()[0].decode().strip()
 scriptlocation = os.path.dirname(os.path.abspath(__file__))
 
-print("repository: "+maindir)
+print(f"repository: {maindir}")
 
-pipe = subprocess.Popen(["git", "describe", "--abbrev=0", "--tags"], stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
+pipe = subprocess.Popen(
+    ["git", "describe", "--abbrev=0", "--tags"],
+    stdout=subprocess.PIPE,
+    stderr=subprocess.STDOUT,
+)
 versionresult = pipe.communicate()[0].decode().strip()
 
-print("last version: "+versionresult )
+print(f"last version: {versionresult}")
 try:
-  currentv = extractnumbers(versionresult)
+    currentv = extractnumbers(versionresult)
 except:
-  currentv = [0,0,0]
-if(len(sys.argv) != 2):
-    nextv = (currentv[0],currentv[1], currentv[2]+1)
-    print ("please specify version number, e.g. "+toversionstring(*nextv))
+    currentv = [0, 0, 0]
+if len(sys.argv) != 2:
+    nextv = (currentv[0], currentv[1], currentv[2] + 1)
+    print(f"please specify version number, e.g. {toversionstring(*nextv)}")
     sys.exit(-1)
 try:
     newversion = extractnumbers(sys.argv[1])
     print(newversion)
 except:
-    print("can't parse version number "+sys.argv[1])
+    print(f"can't parse version number {sys.argv[1]}")
     sys.exit(-1)
 
 print("checking that new version is valid")
-if(newversion[0] !=  currentv[0]):
-    assert newversion[0] ==  currentv[0] + 1
+if newversion[0] != currentv[0]:
+    assert newversion[0] == currentv[0] + 1
     assert newversion[1] == 0
     assert newversion[2] == 0
-elif (newversion[1] !=  currentv[1]):
-    assert newversion[1] ==  currentv[1] + 1
+elif newversion[1] != currentv[1]:
+    assert newversion[1] == currentv[1] + 1
     assert newversion[2] == 0
-else :
-    assert newversion[2] ==  currentv[2] + 1
-
-atleastminor= (currentv[0] != newversion[0]) or (currentv[1] != newversion[1])
-
+else:
+    assert newversion[2] == currentv[2] + 1
 
+atleastminor = (currentv[0] != newversion[0]) or (currentv[1] != newversion[1])
 
 newmajorversionstring = str(newversion[0])
-mewminorversionstring = str(newversion[1])
-newrevversionstring = str(newversion[2])
-newversionstring = str(newversion[0]) + "." + str(newversion[1]) + "." + str(newversion[2])
-cmakefile = maindir + os.sep + "CMakeLists.txt"
+newminorversionstring = str(newversion[1])
+newpatchversionstring = str(newversion[2])
+newversionstring = f"{newversion[0]}.{newversion[1]}.{newversion[2]}"
+cmakefile = f"{maindir}{os.sep}CMakeLists.txt"
 
-
-for line in fileinput.input(cmakefile, inplace=1, backup='.bak'):
-    line = re.sub(r'project\(fast_float VERSION \d+\.\d+\.\d+ LANGUAGES CXX\)','project(fast_float VERSION '+newmajorversionstring+'.'+mewminorversionstring+'.'+newrevversionstring+" LANGUAGES CXX)", line.rstrip())
+for line in fileinput.input(cmakefile, inplace=1, backup=".bak"):
+    line = re.sub(
+        r"project\(fast_float VERSION \d+\.\d+\.\d+ LANGUAGES CXX\)",
+        f"project(fast_float VERSION {newversionstring} LANGUAGES CXX)",
+        line.rstrip(),
+    )
     print(line)
 
-print("modified "+cmakefile+", a backup was made")
+print(f"modified {cmakefile}, a backup was made")
 
+versionfilerel = f"{os.sep}include{os.sep}fast_float{os.sep}float_common.h"
+versionfile = f"{maindir}{versionfilerel}"
 
-readmefile = maindir + os.sep + "README.md"
-
-
-for line in fileinput.input(readmefile, inplace=1, backup='.bak'):
-    line = re.sub(r'https://github.com/fastfloat/fast_float/releases/download/v(\d+\.\d+\.\d+)/fast_float.h','https://github.com/fastfloat/fast_float/releases/download/v'+newmajorversionstring+'.'+mewminorversionstring+'.'+newrevversionstring+'/fast_float.h', line.rstrip())
+for line in fileinput.input(versionfile, inplace=1, backup=".bak"):
+    line = re.sub(
+        r"#define FASTFLOAT_VERSION_MAJOR \d+",
+        f"#define FASTFLOAT_VERSION_MAJOR {newmajorversionstring}",
+        line.rstrip(),
+    )
+    line = re.sub(
+        r"#define FASTFLOAT_VERSION_MINOR \d+",
+        f"#define FASTFLOAT_VERSION_MINOR {newminorversionstring}",
+        line.rstrip(),
+    )
+    line = re.sub(
+        r"#define FASTFLOAT_VERSION_PATCH \d+",
+        f"#define FASTFLOAT_VERSION_PATCH {newpatchversionstring}",
+        line.rstrip(),
+    )
     print(line)
 
-print("modified "+readmefile+", a backup was made")
+print(f"{versionfile} modified")
 
+readmefile = f"{maindir}{os.sep}README.md"
+
+for line in fileinput.input(readmefile, inplace=1, backup=".bak"):
+    line = re.sub(
+        r"https://github.com/fastfloat/fast_float/releases/download/v(\d+\.\d+\.\d+)/fast_float.h",
+        f"https://github.com/fastfloat/fast_float/releases/download/v{newversionstring}/fast_float.h",
+        line.rstrip(),
+    )
+    line = re.sub(
+        r"GIT_TAG tags/v(\d+\.\d+\.\d+)",
+        f"GIT_TAG tags/v{newversionstring}",
+        line.rstrip(),
+    )
+    line = re.sub(
+        r"GIT_TAG v(\d+\.\d+\.\d+)\)", f"GIT_TAG v{newversionstring})", line.rstrip()
+    )
+    print(line)
+
+print(f"modified {readmefile}, a backup was made")
 
 print("running amalgamate.py")
-with open(maindir+ os.sep + 'fast_float.h', "w") as outfile:
-    cp = subprocess.run(["python3", maindir+ os.sep + "script/amalgamate.py"], stdout=outfile)  
+with open(f"{maindir}{os.sep}fast_float.h", "w") as outfile:
+    cp = subprocess.run(
+        [f"python3", f"{maindir}{os.sep}script{os.sep}amalgamate.py"], stdout=outfile
+    )
 
-if(cp.returncode != 0):
+if cp.returncode != 0:
     print("Failed to run amalgamate")
 else:
     print("amalgamate.py ran successfully")
-    print("You should upload "+ maindir+ os.sep + 'fast_float.h')
-
-print("Please run the tests before issuing a release. \n")
-print("to issue release, enter \n git commit -a && git push  &&  git tag -a v"+toversionstring(*newversion)+" -m \"version "+toversionstring(*newversion)+"\" &&  git push --tags \n")
-
-
+    print(f"You should upload {maindir}{os.sep}fast_float.h")
 
+print("Please run the tests before issuing a release.\n")
+print(
+    f'to issue release, enter\n git commit -a && git push && git tag -a v{toversionstring(*newversion)} -m "version {toversionstring(*newversion)}" && git push --tags\n'
+)

script/table_generation.py

@@ -1,14 +1,15 @@
 def format(number):
-    upper = number // (1<<64)
-    lower = number % (1<<64)
-    print(""+hex(upper)+","+hex(lower)+",")
+    upper = number // (1 << 64)
+    lower = number % (1 << 64)
+    print("" + hex(upper) + "," + hex(lower) + ",")
 
-for q in range(-342,0):
+
+for q in range(-342, 0):
     power5 = 5 ** -q
     z = 0
-    while( (1<<z) < power5) :
+    while (1 << z) < power5:
         z += 1
-    if(q >= -27):
+    if q >= -27:
         b = z + 127
         c = 2 ** b // power5 + 1
         format(c)
@@ -16,16 +17,16 @@ for q in range(-342,0):
         b = 2 * z + 2 * 64
         c = 2 ** b // power5 + 1
         # truncate
-        while(c >= (1<<128)):
-          c //= 2
+        while c >= (1 << 128):
+            c //= 2
         format(c)
 
-for q in range(0,308+1):
+for q in range(0, 308 + 1):
     power5 = 5 ** q
     # move the most significant bit in position
-    while(power5 < (1<<127)):
+    while power5 < (1 << 127):
         power5 *= 2
     # *truncate*
-    while(power5 >= (1<<128)):
+    while power5 >= (1 << 128):
         power5 //= 2
     format(power5)

tests/BUILD.bazel

@@ -0,0 +1,116 @@
+cc_test(
+    name = "basictest",
+    srcs = ["basictest.cpp"],
+    deps = [
+        "//:fast_float",
+        "@doctest//doctest",
+    ],
+)
+
+cc_test(
+    name = "example_test",
+    srcs = ["example_test.cpp"],
+    deps = [
+        "//:fast_float",
+        "@doctest//doctest",
+    ],
+)
+
+cc_test(
+    name = "example_comma_test",
+    srcs = ["example_comma_test.cpp"],
+    deps = [
+        "//:fast_float",
+        "@doctest//doctest",
+    ],
+)
+
+cc_test(
+    name = "fast_int",
+    srcs = ["fast_int.cpp"],
+    deps = [
+        "//:fast_float",
+        "@doctest//doctest",
+    ],
+)
+
+cc_test(
+    name = "fixedwidthtest",
+    srcs = ["fixedwidthtest.cpp"],
+    deps = [
+        "//:fast_float",
+        "@doctest//doctest",
+    ],
+)
+
+cc_test(
+    name = "fortran",
+    srcs = ["fortran.cpp"],
+    deps = [
+        "//:fast_float",
+        "@doctest//doctest",
+    ],
+)
+
+cc_test(
+    name = "json_fmt",
+    srcs = ["json_fmt.cpp"],
+    deps = [
+        "//:fast_float",
+        "@doctest//doctest",
+    ],
+)
+
+cc_test(
+    name = "long_test",
+    srcs = ["long_test.cpp"],
+    deps = [
+        "//:fast_float",
+        "@doctest//doctest",
+    ],
+)
+
+cc_test(
+    name = "powersoffive_hardround",
+    srcs = ["powersoffive_hardround.cpp"],
+    deps = [
+        "//:fast_float",
+        "@doctest//doctest",
+    ],
+)
+
+cc_test(
+    name = "rcppfastfloat_test",
+    srcs = ["rcppfastfloat_test.cpp"],
+    deps = [
+        "//:fast_float",
+        "@doctest//doctest",
+    ],
+)
+
+cc_test(
+    name = "wide_char_test",
+    srcs = ["wide_char_test.cpp"],
+    deps = [
+        "//:fast_float",
+        "@doctest//doctest",
+    ],
+)
+
+cc_test(
+    name = "supported_chars_test",
+    srcs = ["supported_chars_test.cpp"],
+    deps = [
+        "//:fast_float",
+        "@doctest//doctest",
+    ],
+)
+
+cc_test(
+    name = "string_test",
+    srcs = ["string_test.cpp"],
+    deps = [
+        "//:fast_float",
+        "@doctest//doctest",
+    ],
+)

tests/CMakeLists.txt

@@ -9,8 +9,9 @@ option(FASTFLOAT_SUPPLEMENTAL_TESTS "Run supplemental tests" ON)
 
 if (NOT SYSTEM_DOCTEST)
   FetchContent_Declare(doctest
-    GIT_REPOSITORY https://github.com/onqtam/doctest.git
-    GIT_TAG v2.4.11)
+    GIT_REPOSITORY https://github.com/lemire/doctest.git)
+else ()
+  find_package(doctest REQUIRED)
 endif()
 if (FASTFLOAT_SUPPLEMENTAL_TESTS)
   FetchContent_Declare(supplemental_test_files
@@ -21,24 +22,15 @@ endif()
 
 # FetchContent_MakeAvailable() was only introduced in 3.14
 # https://cmake.org/cmake/help/v3.14/release/3.14.html#modules
-# FetchContent_MakeAvailable(doctest)
 if (NOT SYSTEM_DOCTEST)
-  FetchContent_GetProperties(doctest)
-  if(NOT doctest_POPULATED)
-    FetchContent_Populate(doctest)
-    add_subdirectory(${doctest_SOURCE_DIR} ${doctest_BINARY_DIR})
-  endif()
+  FetchContent_MakeAvailable(doctest)
 endif()
 
 add_library(supplemental-data INTERFACE)
 if (FASTFLOAT_SUPPLEMENTAL_TESTS)
-  FetchContent_GetProperties(supplemental_test_files)
-  if(NOT supplemental_test_files_POPULATED)
-    message(STATUS "Supplemental tests enabled. Retrieving test files.")
-    FetchContent_Populate(supplemental_test_files)
-    message(STATUS "Supplemental test files retrieved.")
-    add_subdirectory(${supplemental_test_files_SOURCE_DIR} ${supplemental_test_files_BINARY_DIR})
-  endif()
+  message(STATUS "Supplemental tests enabled. Retrieving test files.")
+  FetchContent_MakeAvailable(supplemental_test_files)
+  message(STATUS "Supplemental test files retrieved.")
   target_compile_definitions(supplemental-data INTERFACE SUPPLEMENTAL_TEST_DATA_DIR="${supplemental_test_files_BINARY_DIR}/data")
 endif()
 
@@ -59,12 +51,17 @@ function(fast_float_add_cpp_test TEST_NAME)
     target_link_libraries(${TEST_NAME} PUBLIC fast_float supplemental-data)
     if (NOT SYSTEM_DOCTEST)
       target_link_libraries(${TEST_NAME} PUBLIC doctest)
+    else ()
+      target_link_libraries(${TEST_NAME} PUBLIC doctest::doctest)
     endif()
 endfunction(fast_float_add_cpp_test)
 
 fast_float_add_cpp_test(rcppfastfloat_test)
+fast_float_add_cpp_test(wide_char_test)
+fast_float_add_cpp_test(supported_chars_test)
 fast_float_add_cpp_test(example_test)
 fast_float_add_cpp_test(example_comma_test)
+fast_float_add_cpp_test(example_integer_times_pow10)
 fast_float_add_cpp_test(basictest)
 option(FASTFLOAT_CONSTEXPR_TESTS "Require constexpr tests (build will fail if the compiler won't support it)" OFF)
 if (FASTFLOAT_CONSTEXPR_TESTS)
@@ -76,7 +73,7 @@ endif()
 if (FASTFLOAT_SUPPLEMENTAL_TESTS)
   target_compile_definitions(basictest PRIVATE FASTFLOAT_SUPPLEMENTAL_TESTS)
 endif()
-
+fast_float_add_cpp_test(p2497)
 fast_float_add_cpp_test(long_test)
 fast_float_add_cpp_test(powersoffive_hardround)
 fast_float_add_cpp_test(string_test)

tests/bloat_analysis/a1.cpp

@@ -1,6 +1,6 @@
 #include "fast_float/fast_float.h"
 
-double get1(const char *input) {
+double get1(char const *input) {
   double result_value;
   auto result =
       fast_float::from_chars(input, input + strlen(input), result_value);

tests/bloat_analysis/a10.cpp

@@ -1,6 +1,6 @@
 #include "fast_float/fast_float.h"
 
-double get10(const char *input) {
+double get10(char const *input) {
   double result_value;
   auto result =
       fast_float::from_chars(input, input + strlen(input), result_value);

tests/bloat_analysis/a2.cpp

@@ -1,6 +1,6 @@
 #include "fast_float/fast_float.h"
 
-double get2(const char *input) {
+double get2(char const *input) {
   double result_value;
   auto result =
       fast_float::from_chars(input, input + strlen(input), result_value);

tests/bloat_analysis/a3.cpp

@@ -1,6 +1,6 @@
 #include "fast_float/fast_float.h"
 
-double get3(const char *input) {
+double get3(char const *input) {
   double result_value;
   auto result =
       fast_float::from_chars(input, input + strlen(input), result_value);

tests/bloat_analysis/a4.cpp

@@ -1,6 +1,6 @@
 #include "fast_float/fast_float.h"
 
-double get4(const char *input) {
+double get4(char const *input) {
   double result_value;
   auto result =
       fast_float::from_chars(input, input + strlen(input), result_value);

tests/bloat_analysis/a5.cpp

@@ -1,6 +1,6 @@
 #include "fast_float/fast_float.h"
 
-double get5(const char *input) {
+double get5(char const *input) {
   double result_value;
   auto result =
       fast_float::from_chars(input, input + strlen(input), result_value);

tests/bloat_analysis/a6.cpp

@@ -1,6 +1,6 @@
 #include "fast_float/fast_float.h"
 
-double get6(const char *input) {
+double get6(char const *input) {
   double result_value;
   auto result =
       fast_float::from_chars(input, input + strlen(input), result_value);

tests/bloat_analysis/a7.cpp

@@ -1,6 +1,6 @@
 #include "fast_float/fast_float.h"
 
-double get7(const char *input) {
+double get7(char const *input) {
   double result_value;
   auto result =
       fast_float::from_chars(input, input + strlen(input), result_value);

tests/bloat_analysis/a8.cpp

@@ -1,6 +1,6 @@
 #include "fast_float/fast_float.h"
 
-double get8(const char *input) {
+double get8(char const *input) {
   double result_value;
   auto result =
       fast_float::from_chars(input, input + strlen(input), result_value);

tests/bloat_analysis/a9.cpp

@@ -1,6 +1,6 @@
 #include "fast_float/fast_float.h"
 
-double get9(const char *input) {
+double get9(char const *input) {
   double result_value;
   auto result =
       fast_float::from_chars(input, input + strlen(input), result_value);

tests/bloat_analysis/main.cpp

@@ -1,15 +1,15 @@
 
 
-double get1(const char *input);
-double get2(const char *input);
-double get3(const char *input);
-double get4(const char *input);
-double get5(const char *input);
-double get6(const char *input);
-double get7(const char *input);
-double get8(const char *input);
-double get9(const char *input);
-double get10(const char *input);
+double get1(char const *input);
+double get2(char const *input);
+double get3(char const *input);
+double get4(char const *input);
+double get5(char const *input);
+double get6(char const *input);
+double get7(char const *input);
+double get8(char const *input);
+double get9(char const *input);
+double get10(char const *input);
 
 int main(int arg, char **argv) {
   double x = get1(argv[0]) + get2(argv[0]) + get3(argv[0]) + get4(argv[0]) +

tests/bloat_analysis/main_ref.cpp

@@ -1,6 +1,6 @@
 #include "fast_float/fast_float.h"
 
-double get(const char *input) {
+double get(char const *input) {
   double result_value;
   auto result =
       fast_float::from_chars(input, input + strlen(input), result_value);

tests/build_tests/issue72/foo.cpp

@@ -1,2 +1,3 @@
 #include "test.h"
+
 void foo() {}

tests/build_tests/issue72/main.cpp

@@ -1,2 +1,3 @@
 #include "test.h"
+
 int main() { return 0; }

tests/example_comma_test.cpp

@@ -5,7 +5,7 @@
 #include <system_error>
 
 int main() {
-  const std::string input = "3,1416 xyz ";
+  std::string const input = "3,1416 xyz ";
   double result;
   fast_float::parse_options options{fast_float::chars_format::general, ','};
   auto answer = fast_float::from_chars_advanced(

tests/example_integer_times_pow10.cpp

@@ -0,0 +1,36 @@
+#include "fast_float/fast_float.h"
+
+#include <iostream>
+
+void default_overload() {
+  const uint64_t W = 12345678901234567;
+  const int Q = 23;
+  const double result = fast_float::integer_times_pow10(W, Q);
+  std::cout.precision(17);
+  std::cout << W << " * 10^" << Q << " = " << result << " ("
+            << (result == 12345678901234567e23 ? "==" : "!=") << "expected)\n";
+}
+
+void double_specialization() {
+  const uint64_t W = 12345678901234567;
+  const int Q = 23;
+  const double result = fast_float::integer_times_pow10<double>(W, Q);
+  std::cout.precision(17);
+  std::cout << "double: " << W << " * 10^" << Q << " = " << result << " ("
+            << (result == 12345678901234567e23 ? "==" : "!=") << "expected)\n";
+}
+
+void float_specialization() {
+  const uint64_t W = 12345678;
+  const int Q = 23;
+  const float result = fast_float::integer_times_pow10<float>(W, Q);
+  std::cout.precision(9);
+  std::cout << "float: " << W << " * 10^" << Q << " = " << result << " ("
+            << (result == 12345678e23f ? "==" : "!=") << "expected)\n";
+}
+
+int main() {
+  default_overload();
+  double_specialization();
+  float_specialization();
+}

tests/example_test.cpp

@@ -5,7 +5,7 @@
 #include <system_error>
 
 bool many() {
-  const std::string input = "234532.3426362,7869234.9823,324562.645";
+  std::string const input = "234532.3426362,7869234.9823,324562.645";
   double result;
   auto answer =
       fast_float::from_chars(input.data(), input.data() + input.size(), result);
@@ -41,10 +41,10 @@ bool many() {
 }
 
 void many_loop() {
-  const std::string input = "234532.3426362,7869234.9823,324562.645";
+  std::string const input = "234532.3426362,7869234.9823,324562.645";
   double result;
-  const char *pointer = input.data();
-  const char *end_pointer = input.data() + input.size();
+  char const *pointer = input.data();
+  char const *end_pointer = input.data() + input.size();
 
   while (pointer < end_pointer) {
     auto answer = fast_float::from_chars(pointer, end_pointer, result);
@@ -112,7 +112,7 @@ bool large() {
 }
 
 int main() {
-  const std::string input = "3.1416 xyz ";
+  std::string input = "3.1416 xyz ";
   double result;
   auto answer =
       fast_float::from_chars(input.data(), input.data() + input.size(), result);
@@ -121,6 +121,20 @@ int main() {
     return EXIT_FAILURE;
   }
   std::cout << "parsed the number " << result << std::endl;
+#ifdef __STDCPP_FLOAT16_T__
+  printf("16-bit float\n");
+  // Parse as 16-bit float
+  std::float16_t parsed_16{};
+  input = "10000e-1452";
+  auto fast_float_r16 = fast_float::from_chars(
+      input.data(), input.data() + input.size(), parsed_16);
+  if (fast_float_r16.ec != std::errc() &&
+      fast_float_r16.ec != std::errc::result_out_of_range) {
+    std::cerr << "16-bit fast_float parsing failure for: " + input + "\n";
+    return false;
+  }
+  std::cout << "parsed the 16-bit value " << float(parsed_16) << std::endl;
+#endif
   if (!small()) {
     printf("Bug\n");
     return EXIT_FAILURE;

tests/exhaustive32.cpp

@@ -27,7 +27,7 @@ void allvalues() {
     memcpy(&v, &word, sizeof(v));
 
     {
-      const char *string_end = to_string(v, buffer);
+      char const *string_end = to_string(v, buffer);
       float result_value;
       auto result = fast_float::from_chars(buffer, string_end, result_value);
       // Starting with version 4.0 for fast_float, we return result_out_of_range

tests/exhaustive32_64.cpp

@@ -58,7 +58,7 @@ void all_32bit_values() {
     double v = v32;
 
     {
-      const char *string_end = to_string(v, buffer);
+      char const *string_end = to_string(v, buffer);
       std::string s(buffer, size_t(string_end - buffer));
       if (!basic_test_64bit(s, v)) {
         return;

tests/exhaustive32_midpoint.cpp

@@ -14,8 +14,9 @@
 // gcc.
 #include <locale>
 #include <sstream>
+
 // workaround for CYGWIN
-double cygwin_strtod_l(const char *start, char **end) {
+double cygwin_strtod_l(char const *start, char **end) {
   double d;
   std::stringstream ss;
   ss.imbue(std::locale::classic());
@@ -31,7 +32,8 @@ double cygwin_strtod_l(const char *start, char **end) {
   *end = const_cast<char *>(start) + nread;
   return d;
 }
-float cygwin_strtof_l(const char *start, char **end) {
+
+float cygwin_strtof_l(char const *start, char **end) {
   float d;
   std::stringstream ss;
   ss.imbue(std::locale::classic());
@@ -55,7 +57,7 @@ template <typename T> char *to_string(T d, char *buffer) {
   return buffer + written;
 }
 
-void strtof_from_string(const char *st, float &d) {
+void strtof_from_string(char const *st, float &d) {
   char *pr = (char *)st;
 #if defined(__CYGWIN__) || defined(__MINGW32__) || defined(__MINGW64__) ||     \
     defined(sun) || defined(__sun)
@@ -97,7 +99,7 @@ bool allvalues() {
       double midv{v1 + (v2 - v1) / 2};
       float expected_midv = float(midv);
 
-      const char *string_end = to_string(midv, buffer);
+      char const *string_end = to_string(midv, buffer);
       float str_answer;
       strtof_from_string(buffer, str_answer);
 
@@ -164,6 +166,7 @@ inline void Assert(bool Assertion) {
   }
 #endif
 }
+
 int main() {
 #if defined(__CYGWIN__) || defined(__MINGW32__) || defined(__MINGW64__) ||     \
     defined(sun) || defined(__sun)

tests/fast_int.cpp

@@ -46,12 +46,12 @@ ignores all zeroes in front of valid number after converted from base
 
 int main() {
   // int basic test
-  const std::vector<int> int_basic_test_expected{0, 10, -40, 1001, 9};
-  const std::vector<std::string_view> int_basic_test{"0", "10 ", "-40",
+  std::vector<int> const int_basic_test_expected{0, 10, -40, 1001, 9};
+  std::vector<std::string_view> const int_basic_test{"0", "10 ", "-40",
                                                      "1001 with text", "9.999"};
 
   for (std::size_t i = 0; i < int_basic_test.size(); ++i) {
-    const auto f = int_basic_test[i];
+    auto const f = int_basic_test[i];
     int result;
     auto answer = fast_float::from_chars(f.data(), f.data() + f.size(), result);
 
@@ -75,12 +75,12 @@ int main() {
   }
 
   // unsigned basic test
-  const std::vector<unsigned> unsigned_basic_test_expected{0, 10, 1001, 9};
-  const std::vector<std::string_view> unsigned_basic_test{
+  std::vector<unsigned> const unsigned_basic_test_expected{0, 10, 1001, 9};
+  std::vector<std::string_view> const unsigned_basic_test{
       "0", "10 ", "1001 with text", "9.999"};
 
   for (std::size_t i = 0; i < unsigned_basic_test.size(); ++i) {
-    const auto &f = unsigned_basic_test[i];
+    auto const &f = unsigned_basic_test[i];
     unsigned result;
     auto answer = fast_float::from_chars(f.data(), f.data() + f.size(), result);
     if (answer.ec != std::errc()) {
@@ -96,11 +96,11 @@ int main() {
   }
 
   // int invalid error test
-  const std::vector<std::string_view> int_invalid_argument_test{
+  std::vector<std::string_view> const int_invalid_argument_test{
       "text", "text with 1002", "+50", " 50"};
 
   for (std::size_t i = 0; i < int_invalid_argument_test.size(); ++i) {
-    const auto &f = int_invalid_argument_test[i];
+    auto const &f = int_invalid_argument_test[i];
     int result;
     auto answer = fast_float::from_chars(f.data(), f.data() + f.size(), result);
     if (answer.ec != std::errc::invalid_argument) {
@@ -111,11 +111,11 @@ int main() {
   }
 
   // unsigned invalid error test
-  const std::vector<std::string_view> unsigned_invalid_argument_test{
+  std::vector<std::string_view> const unsigned_invalid_argument_test{
       "text", "text with 1002", "+50", " 50", "-50"};
 
   for (std::size_t i = 0; i < unsigned_invalid_argument_test.size(); ++i) {
-    const auto &f = unsigned_invalid_argument_test[i];
+    auto const &f = unsigned_invalid_argument_test[i];
     unsigned result;
     auto answer = fast_float::from_chars(f.data(), f.data() + f.size(), result);
     if (answer.ec != std::errc::invalid_argument) {
@@ -126,11 +126,11 @@ int main() {
   }
 
   // int out of range error test #1 (8 bit)
-  const std::vector<std::string_view> int_out_of_range_test_1{
+  std::vector<std::string_view> const int_out_of_range_test_1{
       "2000000000000000000000", "128", "-129"};
 
   for (std::size_t i = 0; i < int_out_of_range_test_1.size(); ++i) {
-    const auto &f = int_out_of_range_test_1[i];
+    auto const &f = int_out_of_range_test_1[i];
     int8_t result;
     auto answer = fast_float::from_chars(f.data(), f.data() + f.size(), result);
     if (answer.ec != std::errc::result_out_of_range) {
@@ -141,11 +141,11 @@ int main() {
   }
 
   // int out of range error test #2 (16 bit)
-  const std::vector<std::string_view> int_out_of_range_test_2{
+  std::vector<std::string_view> const int_out_of_range_test_2{
       "2000000000000000000000", "32768", "-32769"};
 
   for (std::size_t i = 0; i < int_out_of_range_test_2.size(); ++i) {
-    const auto &f = int_out_of_range_test_2[i];
+    auto const &f = int_out_of_range_test_2[i];
     int16_t result;
     auto answer = fast_float::from_chars(f.data(), f.data() + f.size(), result);
     if (answer.ec != std::errc::result_out_of_range) {
@@ -156,11 +156,11 @@ int main() {
   }
 
   // int out of range error test #3 (32 bit)
-  const std::vector<std::string_view> int_out_of_range_test_3{
+  std::vector<std::string_view> const int_out_of_range_test_3{
       "2000000000000000000000", "2147483648", "-2147483649"};
 
   for (std::size_t i = 0; i < int_out_of_range_test_3.size(); ++i) {
-    const auto &f = int_out_of_range_test_3[i];
+    auto const &f = int_out_of_range_test_3[i];
     int32_t result;
     auto answer = fast_float::from_chars(f.data(), f.data() + f.size(), result);
     if (answer.ec != std::errc::result_out_of_range) {
@@ -171,11 +171,11 @@ int main() {
   }
 
   // int out of range error test #4 (64 bit)
-  const std::vector<std::string_view> int_out_of_range_test_4{
+  std::vector<std::string_view> const int_out_of_range_test_4{
       "2000000000000000000000", "9223372036854775808", "-9223372036854775809"};
 
   for (std::size_t i = 0; i < int_out_of_range_test_4.size(); ++i) {
-    const auto &f = int_out_of_range_test_4[i];
+    auto const &f = int_out_of_range_test_4[i];
     int64_t result;
     auto answer = fast_float::from_chars(f.data(), f.data() + f.size(), result);
     if (answer.ec != std::errc::result_out_of_range) {
@@ -186,11 +186,11 @@ int main() {
   }
 
   // unsigned out of range error test #1 (8 bit)
-  const std::vector<std::string_view> unsigned_out_of_range_test_1{
+  std::vector<std::string_view> const unsigned_out_of_range_test_1{
       "2000000000000000000000", "256"};
 
   for (std::size_t i = 0; i < unsigned_out_of_range_test_1.size(); ++i) {
-    const auto &f = unsigned_out_of_range_test_1[i];
+    auto const &f = unsigned_out_of_range_test_1[i];
     uint8_t result;
     auto answer = fast_float::from_chars(f.data(), f.data() + f.size(), result);
     if (answer.ec != std::errc::result_out_of_range) {
@@ -201,11 +201,11 @@ int main() {
   }
 
   // unsigned out of range error test #2 (16 bit)
-  const std::vector<std::string_view> unsigned_out_of_range_test_2{
+  std::vector<std::string_view> const unsigned_out_of_range_test_2{
       "2000000000000000000000", "65536"};
 
   for (std::size_t i = 0; i < unsigned_out_of_range_test_2.size(); ++i) {
-    const auto &f = unsigned_out_of_range_test_2[i];
+    auto const &f = unsigned_out_of_range_test_2[i];
     uint16_t result;
     auto answer = fast_float::from_chars(f.data(), f.data() + f.size(), result);
     if (answer.ec != std::errc::result_out_of_range) {
@@ -216,11 +216,11 @@ int main() {
   }
 
   // unsigned out of range error test #3 (32 bit)
-  const std::vector<std::string_view> unsigned_out_of_range_test_3{
+  std::vector<std::string_view> const unsigned_out_of_range_test_3{
       "2000000000000000000000", "4294967296"};
 
   for (std::size_t i = 0; i < unsigned_out_of_range_test_3.size(); ++i) {
-    const auto &f = unsigned_out_of_range_test_3[i];
+    auto const &f = unsigned_out_of_range_test_3[i];
     uint32_t result;
     auto answer = fast_float::from_chars(f.data(), f.data() + f.size(), result);
     if (answer.ec != std::errc::result_out_of_range) {
@@ -231,11 +231,11 @@ int main() {
   }
 
   // unsigned out of range error test #4 (64 bit)
-  const std::vector<std::string_view> unsigned_out_of_range_test_4{
+  std::vector<std::string_view> const unsigned_out_of_range_test_4{
       "2000000000000000000000", "18446744073709551616"};
 
   for (std::size_t i = 0; i < unsigned_out_of_range_test_4.size(); ++i) {
-    const auto &f = unsigned_out_of_range_test_4[i];
+    auto const &f = unsigned_out_of_range_test_4[i];
     uint64_t result;
     auto answer = fast_float::from_chars(f.data(), f.data() + f.size(), result);
     if (answer.ec != std::errc::result_out_of_range) {
@@ -246,10 +246,10 @@ int main() {
   }
 
   // int pointer test #1 (only numbers)
-  const std::vector<std::string_view> int_pointer_test_1{"0", "010", "-40"};
+  std::vector<std::string_view> const int_pointer_test_1{"0", "010", "-40"};
 
   for (std::size_t i = 0; i < int_pointer_test_1.size(); ++i) {
-    const auto &f = int_pointer_test_1[i];
+    auto const &f = int_pointer_test_1[i];
     int result;
     auto answer = fast_float::from_chars(f.data(), f.data() + f.size(), result);
     if (answer.ec != std::errc()) {
@@ -264,9 +264,9 @@ int main() {
   }
 
   // int pointer test #2 (string behind numbers)
-  const std::string_view int_pointer_test_2 = "1001 with text";
+  std::string_view const int_pointer_test_2 = "1001 with text";
 
-  const auto &f2 = int_pointer_test_2;
+  auto const &f2 = int_pointer_test_2;
   int result2;
   auto answer2 =
       fast_float::from_chars(f2.data(), f2.data() + f2.size(), result2);
@@ -277,9 +277,9 @@ int main() {
   }
 
   // int pointer test #3 (string with newline behind numbers)
-  const std::string_view int_pointer_test_3 = "1001 with text\n";
+  std::string_view const int_pointer_test_3 = "1001 with text\n";
 
-  const auto &f3 = int_pointer_test_3;
+  auto const &f3 = int_pointer_test_3;
   int result3;
   auto answer3 =
       fast_float::from_chars(f3.data(), f3.data() + f3.size(), result3);
@@ -290,9 +290,9 @@ int main() {
   }
 
   // int pointer test #4 (float)
-  const std::string_view int_pointer_test_4 = "9.999";
+  std::string_view const int_pointer_test_4 = "9.999";
 
-  const auto &f4 = int_pointer_test_4;
+  auto const &f4 = int_pointer_test_4;
   int result4;
   auto answer4 =
       fast_float::from_chars(f4.data(), f4.data() + f4.size(), result4);
@@ -303,9 +303,9 @@ int main() {
   }
 
   // int pointer test #5 (invalid int)
-  const std::string_view int_pointer_test_5 = "+50";
+  std::string_view const int_pointer_test_5 = "+50";
 
-  const auto &f5 = int_pointer_test_5;
+  auto const &f5 = int_pointer_test_5;
   int result5;
   auto answer5 =
       fast_float::from_chars(f5.data(), f5.data() + f5.size(), result5);
@@ -316,9 +316,9 @@ int main() {
   }
 
   // unsigned pointer test #2 (string behind numbers)
-  const std::string_view unsigned_pointer_test_1 = "1001 with text";
+  std::string_view const unsigned_pointer_test_1 = "1001 with text";
 
-  const auto &f6 = unsigned_pointer_test_1;
+  auto const &f6 = unsigned_pointer_test_1;
   unsigned result6;
   auto answer6 =
       fast_float::from_chars(f6.data(), f6.data() + f6.size(), result6);
@@ -329,9 +329,9 @@ int main() {
   }
 
   // unsigned pointer test #2 (invalid unsigned)
-  const std::string_view unsigned_pointer_test_2 = "-50";
+  std::string_view const unsigned_pointer_test_2 = "-50";
 
-  const auto &f7 = unsigned_pointer_test_2;
+  auto const &f7 = unsigned_pointer_test_2;
   unsigned result7;
   auto answer7 =
       fast_float::from_chars(f7.data(), f7.data() + f7.size(), result7);
@@ -342,12 +342,12 @@ int main() {
   }
 
   // int base 2 test
-  const std::vector<int> int_base_2_test_expected{0, 1, 4, 2, -1};
-  const std::vector<std::string_view> int_base_2_test{"0", "1", "100", "010",
+  std::vector<int> const int_base_2_test_expected{0, 1, 4, 2, -1};
+  std::vector<std::string_view> const int_base_2_test{"0", "1", "100", "010",
                                                       "-1"};
 
   for (std::size_t i = 0; i < int_base_2_test.size(); ++i) {
-    const auto f = int_base_2_test[i];
+    auto const f = int_base_2_test[i];
     int result;
     auto answer =
         fast_float::from_chars(f.data(), f.data() + f.size(), result, 2);
@@ -363,12 +363,12 @@ int main() {
   }
 
   // unsigned base 2 test
-  const std::vector<unsigned> unsigned_base_2_test_expected{0, 1, 4, 2};
-  const std::vector<std::string_view> unsigned_base_2_test{"0", "1", "100",
+  std::vector<unsigned> const unsigned_base_2_test_expected{0, 1, 4, 2};
+  std::vector<std::string_view> const unsigned_base_2_test{"0", "1", "100",
                                                            "010"};
 
   for (std::size_t i = 0; i < unsigned_base_2_test.size(); ++i) {
-    const auto &f = unsigned_base_2_test[i];
+    auto const &f = unsigned_base_2_test[i];
     unsigned result;
     auto answer =
         fast_float::from_chars(f.data(), f.data() + f.size(), result, 2);
@@ -384,11 +384,11 @@ int main() {
   }
 
   // int invalid error base 2 test
-  const std::vector<std::string_view> int_invalid_argument_base_2_test{"2", "A",
+  std::vector<std::string_view> const int_invalid_argument_base_2_test{"2", "A",
                                                                        "-2"};
 
   for (std::size_t i = 0; i < int_invalid_argument_base_2_test.size(); ++i) {
-    const auto &f = int_invalid_argument_base_2_test[i];
+    auto const &f = int_invalid_argument_base_2_test[i];
     int result;
     auto answer =
         fast_float::from_chars(f.data(), f.data() + f.size(), result, 2);
@@ -400,12 +400,12 @@ int main() {
   }
 
   // unsigned invalid error base 2 test
-  const std::vector<std::string_view> unsigned_invalid_argument_base_2_test{
+  std::vector<std::string_view> const unsigned_invalid_argument_base_2_test{
       "2", "A", "-1", "-2"};
 
   for (std::size_t i = 0; i < unsigned_invalid_argument_base_2_test.size();
        ++i) {
-    const auto &f = unsigned_invalid_argument_base_2_test[i];
+    auto const &f = unsigned_invalid_argument_base_2_test[i];
     unsigned result;
     auto answer =
         fast_float::from_chars(f.data(), f.data() + f.size(), result, 2);
@@ -417,12 +417,12 @@ int main() {
   }
 
   // octal test
-  const std::vector<int> base_octal_test_expected{0, 1, 7, 8, 9};
-  const std::vector<std::string_view> base_octal_test{"0", "1", "07", "010",
+  std::vector<int> const base_octal_test_expected{0, 1, 7, 8, 9};
+  std::vector<std::string_view> const base_octal_test{"0", "1", "07", "010",
                                                       "0011"};
 
   for (std::size_t i = 0; i < base_octal_test.size(); ++i) {
-    const auto &f = base_octal_test[i];
+    auto const &f = base_octal_test[i];
     int result;
     auto answer =
         fast_float::from_chars(f.data(), f.data() + f.size(), result, 8);
@@ -438,12 +438,12 @@ int main() {
   }
 
   // hex test
-  const std::vector<int> base_hex_test_expected{0, 1, 15, 31, 0, 16};
-  const std::vector<std::string_view> base_hex_test{"0",   "1",    "F",
+  std::vector<int> const base_hex_test_expected{0, 1, 15, 31, 0, 16};
+  std::vector<std::string_view> const base_hex_test{"0",   "1",    "F",
                                                     "01f", "0x11", "10X11"};
 
   for (std::size_t i = 0; i < base_hex_test.size(); ++i) {
-    const auto &f = base_hex_test[i];
+    auto const &f = base_hex_test[i];
     int result;
     auto answer =
         fast_float::from_chars(f.data(), f.data() + f.size(), result, 16);
@@ -459,11 +459,11 @@ int main() {
   }
 
   // invalid base test #1 (-1)
-  const std::vector<std::string_view> invalid_base_test_1{"0", "1", "-1", "F",
+  std::vector<std::string_view> const invalid_base_test_1{"0", "1", "-1", "F",
                                                           "10Z"};
 
   for (std::size_t i = 0; i < invalid_base_test_1.size(); ++i) {
-    const auto &f = invalid_base_test_1[i];
+    auto const &f = invalid_base_test_1[i];
     int result;
     auto answer =
         fast_float::from_chars(f.data(), f.data() + f.size(), result, -1);
@@ -475,11 +475,11 @@ int main() {
   }
 
   // invalid base test #2 (37)
-  const std::vector<std::string_view> invalid_base_test_2{"0", "1", "F", "Z",
+  std::vector<std::string_view> const invalid_base_test_2{"0", "1", "F", "Z",
                                                           "10Z"};
 
   for (std::size_t i = 0; i < invalid_base_test_2.size(); ++i) {
-    const auto &f = invalid_base_test_2[i];
+    auto const &f = invalid_base_test_2[i];
     int result;
     auto answer =
         fast_float::from_chars(f.data(), f.data() + f.size(), result, 37);
@@ -491,7 +491,7 @@ int main() {
   }
 
   // int out of range error base test (64 bit)
-  const std::vector<std::string_view> int_out_of_range_base_test{
+  std::vector<std::string_view> const int_out_of_range_base_test{
       "1000000000000000000000000000000000000000000000000000000000000000",
       "-1000000000000000000000000000000000000000000000000000000000000001",
       "2021110011022210012102010021220101220222",
@@ -564,7 +564,7 @@ int main() {
       "-1Y2P0IJ32E8E9"};
 
   for (std::size_t i = 0; i < int_out_of_range_base_test.size(); ++i) {
-    const auto &f = int_out_of_range_base_test[i];
+    auto const &f = int_out_of_range_base_test[i];
     int64_t result;
     auto answer = fast_float::from_chars(f.data(), f.data() + f.size(), result,
                                          int(2 + (i / 2)));
@@ -576,7 +576,7 @@ int main() {
   }
 
   // unsigned out of range error base test (64 bit)
-  const std::vector<std::string_view> unsigned_out_of_range_base_test{
+  std::vector<std::string_view> const unsigned_out_of_range_base_test{
       "10000000000000000000000000000000000000000000000000000000000000000",
       "11112220022122120101211020120210210211221",
       "100000000000000000000000000000000",
@@ -614,7 +614,7 @@ int main() {
       "3W5E11264SGSG"};
   int base_unsigned = 2;
   for (std::size_t i = 0; i < unsigned_out_of_range_base_test.size(); ++i) {
-    const auto &f = unsigned_out_of_range_base_test[i];
+    auto const &f = unsigned_out_of_range_base_test[i];
     uint64_t result;
     auto answer = fast_float::from_chars(f.data(), f.data() + f.size(), result,
                                          base_unsigned);
@@ -627,7 +627,7 @@ int main() {
   }
 
   // just within range base test (64 bit)
-  const std::vector<std::string_view> int_within_range_base_test{
+  std::vector<std::string_view> const int_within_range_base_test{
       "111111111111111111111111111111111111111111111111111111111111111",
       "-1000000000000000000000000000000000000000000000000000000000000000",
       "2021110011022210012102010021220101220221",
@@ -700,7 +700,7 @@ int main() {
       "-1Y2P0IJ32E8E8"};
 
   for (std::size_t i = 0; i < int_within_range_base_test.size(); ++i) {
-    const auto &f = int_within_range_base_test[i];
+    auto const &f = int_within_range_base_test[i];
     int64_t result;
     auto answer = fast_float::from_chars(f.data(), f.data() + f.size(), result,
                                          int(2 + (i / 2)));
@@ -712,7 +712,7 @@ int main() {
   }
 
   // unsigned within range base test (64 bit)
-  const std::vector<std::string_view> unsigned_within_range_base_test{
+  std::vector<std::string_view> const unsigned_within_range_base_test{
       "1111111111111111111111111111111111111111111111111111111111111111",
       "11112220022122120101211020120210210211220",
       "33333333333333333333333333333333",
@@ -750,7 +750,7 @@ int main() {
       "3W5E11264SGSF"};
   int base_unsigned2 = 2;
   for (std::size_t i = 0; i < unsigned_within_range_base_test.size(); ++i) {
-    const auto &f = unsigned_within_range_base_test[i];
+    auto const &f = unsigned_within_range_base_test[i];
     uint64_t result;
     auto answer = fast_float::from_chars(f.data(), f.data() + f.size(), result,
                                          base_unsigned2);
@@ -764,7 +764,7 @@ int main() {
   }
 
   // int leading zeros test
-  const std::vector<std::string_view> int_leading_zeros_test{
+  std::vector<std::string_view> const int_leading_zeros_test{
       "000000000000000000000000000000000000000000000000000000000000000000000011"
       "11110111",
       "000000000000000000000000000000000000000000000000001101121",
@@ -803,7 +803,7 @@ int main() {
       "00000000000000000000S7"};
 
   for (std::size_t i = 0; i < int_leading_zeros_test.size(); ++i) {
-    const auto &f = int_leading_zeros_test[i];
+    auto const &f = int_leading_zeros_test[i];
     int result;
     auto answer = fast_float::from_chars(f.data(), f.data() + f.size(), result,
                                          int(i + 2));
@@ -831,6 +831,275 @@ int main() {
       return EXIT_FAILURE;
     }
   }
+  // dont parse UTF-16 code units of emojis as int if low byte is ascii digit
+  {
+    const std::u16string emojis[] = {
+        u"ℹ", u"ℹ️", u"☸", u"☸️", u"☹", u"☹️", u"✳",  u"✳️",
+        u"✴", u"✴️", u"⤴", u"⤴️", u"⤵", u"⤵️", u"〰", u"〰️",
+    };
+    bool failed = false;
+    auto array_size = sizeof(emojis) / sizeof(emojis[0]);
+    for (size_t i = 0; i < array_size; i++) {
+      auto e = emojis[i];
+      int foo;
+      auto answer = fast_float::from_chars(e.data(), e.data() + e.size(), foo);
+      if (answer.ec == std::errc()) {
+        failed = true;
+        std::cerr << "Incorrectly parsed emoji #" << i << " as integer " << foo
+                  << "." << std::endl;
+      }
+    }
+
+    if (failed) {
+      return EXIT_FAILURE;
+    }
+  }
+  // dont parse UTF-32 code points of emojis as int if low byte is ascii digit
+  {
+    const std::u32string emojis[] = {
+        U"ℹ",
+        U"ℹ️",
+        U"☸",
+        U"☸️",
+        U"☹",
+        U"☹️",
+        U"✳",
+        U"✳️",
+        U"✴",
+        U"✴️",
+        U"⤴",
+        U"⤴️",
+        U"⤵",
+        U"⤵️",
+        U"〰",
+        U"〰️",
+        U"🈲",
+        U"🈳",
+        U"🈴",
+        U"🈵",
+        U"🈶",
+        U"🈷",
+        U"🈷️",
+        U"🈸",
+        U"🈹",
+        U"🌰",
+        U"🌱",
+        U"🌲",
+        U"🌳",
+        U"🌴",
+        U"🌵",
+        U"🌶",
+        U"🌶️",
+        U"🌷",
+        U"🌸",
+        U"🌹",
+        U"🐰",
+        U"🐱",
+        U"🐲",
+        U"🐳",
+        U"🐴",
+        U"🐵",
+        U"🐶",
+        U"🐷",
+        U"🐸",
+        U"🐹",
+        U"🔰",
+        U"🔱",
+        U"🔲",
+        U"🔳",
+        U"🔴",
+        U"🔵",
+        U"🔶",
+        U"🔷",
+        U"🔸",
+        U"🔹",
+        U"😰",
+        U"😱",
+        U"😲",
+        U"😳",
+        U"😴",
+        U"😵",
+        U"😵‍💫",
+        U"😶",
+        U"😶‍🌫",
+        U"😶‍🌫️",
+        U"😷",
+        U"😸",
+        U"😹",
+        U"🤰",
+        U"🤰🏻",
+        U"🤰🏼",
+        U"🤰🏽",
+        U"🤰🏾",
+        U"🤰🏿",
+        U"🤱",
+        U"🤱🏻",
+        U"🤱🏼",
+        U"🤱🏽",
+        U"🤱🏾",
+        U"🤱🏿",
+        U"🤲",
+        U"🤲🏻",
+        U"🤲🏼",
+        U"🤲🏽",
+        U"🤲🏾",
+        U"🤲🏿",
+        U"🤳",
+        U"🤳🏻",
+        U"🤳🏼",
+        U"🤳🏽",
+        U"🤳🏾",
+        U"🤳🏿",
+        U"🤴",
+        U"🤴🏻",
+        U"🤴🏼",
+        U"🤴🏽",
+        U"🤴🏾",
+        U"🤴🏿",
+        U"🤵",
+        U"🤵‍♀",
+        U"🤵‍♀️",
+        U"🤵‍♂",
+        U"🤵‍♂️",
+        U"🤵🏻",
+        U"🤵🏻‍♀",
+        U"🤵🏻‍♀️",
+        U"🤵🏻‍♂",
+        U"🤵🏻‍♂️",
+        U"🤵🏼",
+        U"🤵🏼‍♀",
+        U"🤵🏼‍♀️",
+        U"🤵🏼‍♂",
+        U"🤵🏼‍♂️",
+        U"🤵🏽",
+        U"🤵🏽‍♀",
+        U"🤵🏽‍♀️",
+        U"🤵🏽‍♂",
+        U"🤵🏽‍♂️",
+        U"🤵🏾",
+        U"🤵🏾‍♀",
+        U"🤵🏾‍♀️",
+        U"🤵🏾‍♂",
+        U"🤵🏾‍♂️",
+        U"🤵🏿",
+        U"🤵🏿‍♀",
+        U"🤵🏿‍♀️",
+        U"🤵🏿‍♂",
+        U"🤵🏿‍♂️",
+        U"🤶",
+        U"🤶🏻",
+        U"🤶🏼",
+        U"🤶🏽",
+        U"🤶🏾",
+        U"🤶🏿",
+        U"🤷",
+        U"🤷‍♀",
+        U"🤷‍♀️",
+        U"🤷‍♂",
+        U"🤷‍♂️",
+        U"🤷🏻",
+        U"🤷🏻‍♀",
+        U"🤷🏻‍♀️",
+        U"🤷🏻‍♂",
+        U"🤷🏻‍♂️",
+        U"🤷🏼",
+        U"🤷🏼‍♀",
+        U"🤷🏼‍♀️",
+        U"🤷🏼‍♂",
+        U"🤷🏼‍♂️",
+        U"🤷🏽",
+        U"🤷🏽‍♀",
+        U"🤷🏽‍♀️",
+        U"🤷🏽‍♂",
+        U"🤷🏽‍♂️",
+        U"🤷🏾",
+        U"🤷🏾‍♀",
+        U"🤷🏾‍♀️",
+        U"🤷🏾‍♂",
+        U"🤷🏾‍♂️",
+        U"🤷🏿",
+        U"🤷🏿‍♀",
+        U"🤷🏿‍♀️",
+        U"🤷🏿‍♂",
+        U"🤷🏿‍♂️",
+        U"🤸",
+        U"🤸‍♀",
+        U"🤸‍♀️",
+        U"🤸‍♂",
+        U"🤸‍♂️",
+        U"🤸🏻",
+        U"🤸🏻‍♀",
+        U"🤸🏻‍♀️",
+        U"🤸🏻‍♂",
+        U"🤸🏻‍♂️",
+        U"🤸🏼",
+        U"🤸🏼‍♀",
+        U"🤸🏼‍♀️",
+        U"🤸🏼‍♂",
+        U"🤸🏼‍♂️",
+        U"🤸🏽",
+        U"🤸🏽‍♀",
+        U"🤸🏽‍♀️",
+        U"🤸🏽‍♂",
+        U"🤸🏽‍♂️",
+        U"🤸🏾",
+        U"🤸🏾‍♀",
+        U"🤸🏾‍♀️",
+        U"🤸🏾‍♂",
+        U"🤸🏾‍♂️",
+        U"🤸🏿",
+        U"🤸🏿‍♀",
+        U"🤸🏿‍♀️",
+        U"🤸🏿‍♂",
+        U"🤸🏿‍♂️",
+        U"🤹",
+        U"🤹‍♀",
+        U"🤹‍♀️",
+        U"🤹‍♂",
+        U"🤹‍♂️",
+        U"🤹🏻",
+        U"🤹🏻‍♀",
+        U"🤹🏻‍♀️",
+        U"🤹🏻‍♂",
+        U"🤹🏻‍♂️",
+        U"🤹🏼",
+        U"🤹🏼‍♀",
+        U"🤹🏼‍♀️",
+        U"🤹🏼‍♂",
+        U"🤹🏼‍♂️",
+        U"🤹🏽",
+        U"🤹🏽‍♀",
+        U"🤹🏽‍♀️",
+        U"🤹🏽‍♂",
+        U"🤹🏽‍♂️",
+        U"🤹🏾",
+        U"🤹🏾‍♀",
+        U"🤹🏾‍♀️",
+        U"🤹🏾‍♂",
+        U"🤹🏾‍♂️",
+        U"🤹🏿",
+        U"🤹🏿‍♀",
+        U"🤹🏿‍♀️",
+        U"🤹🏿‍♂",
+        U"🤹🏿‍♂️",
+    };
+    bool failed = false;
+    auto array_size = sizeof(emojis) / sizeof(emojis[0]);
+    for (size_t i = 0; i < array_size; i++) {
+      auto e = emojis[i];
+      int foo;
+      auto answer = fast_float::from_chars(e.data(), e.data() + e.size(), foo);
+      if (answer.ec == std::errc()) {
+        failed = true;
+        std::cerr << "Incorrectly parsed emoji #" << i << " as integer " << foo
+                  << "." << std::endl;
+      }
+    }
+
+    if (failed) {
+      return EXIT_FAILURE;
+    }
+  }
 
   return EXIT_SUCCESS;
 }
@@ -842,4 +1111,4 @@ int main() {
   std::cerr << "The test requires C++17." << std::endl;
   return EXIT_SUCCESS;
 }
-#endif
+#endif

tests/fixedwidthtest.cpp

@@ -4,19 +4,22 @@
 #include <cstring>
 #include "fast_float/fast_float.h"
 #include <cstdint>
+
+#if __cplusplus >= 202300L
 #include <stdfloat>
+#endif
 
 int main() {
   // Write some testcases for the parsing of floating point numbers in the
   // float32_t type. We use the from_chars function defined in this library.
-#if __STDCPP_FLOAT32_T__
-  const std::vector<std::float32_t> float32_test_expected{
+#ifdef __STDCPP_FLOAT32_T__
+  std::vector<std::float32_t> const float32_test_expected{
       123.456f, -78.9f, 0.0001f, 3.40282e+038f};
-  const std::vector<std::string_view> float32_test{"123.456", "-78.9", "0.0001",
+  std::vector<std::string_view> const float32_test{"123.456", "-78.9", "0.0001",
                                                    "3.40282e+038"};
   std::cout << "runing float32 test" << std::endl;
   for (std::size_t i = 0; i < float32_test.size(); ++i) {
-    const auto &f = float32_test[i];
+    auto const &f = float32_test[i];
     std::float32_t result;
     auto answer = fast_float::from_chars(f.data(), f.data() + f.size(), result);
 
@@ -34,16 +37,16 @@ int main() {
   std::cout << "No std::float32_t type available." << std::endl;
 #endif
 
-#if __STDCPP_FLOAT64_T__
+#ifdef __STDCPP_FLOAT64_T__
   // Test cases for std::float64_t
-  const std::vector<std::float64_t> float64_test_expected{
+  std::vector<std::float64_t> const float64_test_expected{
       1.23e4, -5.67e-8, 1.7976931348623157e+308, -1.7976931348623157e+308};
-  const std::vector<std::string_view> float64_test{"1.23e4", "-5.67e-8",
+  std::vector<std::string_view> const float64_test{"1.23e4", "-5.67e-8",
                                                    "1.7976931348623157e+308",
                                                    "-1.7976931348623157e+308"};
   std::cout << "runing float64 test" << std::endl;
   for (std::size_t i = 0; i < float64_test.size(); ++i) {
-    const auto &f = float64_test[i];
+    auto const &f = float64_test[i];
     std::float64_t result;
     auto answer = fast_float::from_chars(f.data(), f.data() + f.size(), result);
 

tests/fortran.cpp

@@ -4,15 +4,14 @@
 #include <cstdlib>
 #include <iostream>
 #include <vector>
-
-#define FASTFLOAT_ALLOWS_LEADING_PLUS
-
 #include "fast_float/fast_float.h"
 
 int main_readme() {
-  const std::string input = "1d+4";
+  std::string const input = "1d+4";
   double result;
-  fast_float::parse_options options{fast_float::chars_format::fortran};
+  fast_float::parse_options options{
+      fast_float::chars_format::fortran |
+      fast_float::chars_format::allow_leading_plus};
   auto answer = fast_float::from_chars_advanced(
       input.data(), input.data() + input.size(), result, options);
   if ((answer.ec != std::errc()) || ((result != 10000))) {
@@ -24,15 +23,17 @@ int main_readme() {
 }
 
 int main() {
-  const std::vector<double> expected{10000, 1000, 100,  10,   1,
+  std::vector<double> const expected{10000, 1000, 100,  10,   1,
                                      .1,    .01,  .001, .0001};
-  const std::vector<std::string> fmt1{"1+4", "1+3", "1+2", "1+1", "1+0",
+  std::vector<std::string> const fmt1{"1+4", "1+3", "1+2", "1+1", "1+0",
                                       "1-1", "1-2", "1-3", "1-4"};
-  const std::vector<std::string> fmt2{"1d+4", "1d+3", "1d+2", "1d+1", "1d+0",
+  std::vector<std::string> const fmt2{"1d+4", "1d+3", "1d+2", "1d+1", "1d+0",
                                       "1d-1", "1d-2", "1d-3", "1d-4"};
-  const std::vector<std::string> fmt3{"+1+4", "+1+3", "+1+2", "+1+1", "+1+0",
+  std::vector<std::string> const fmt3{"+1+4", "+1+3", "+1+2", "+1+1", "+1+0",
                                       "+1-1", "+1-2", "+1-3", "+1-4"};
-  const fast_float::parse_options options{fast_float::chars_format::fortran};
+  fast_float::parse_options const options{
+      fast_float::chars_format::fortran |
+      fast_float::chars_format::allow_leading_plus};
 
   for (auto const &f : fmt1) {
     auto d{std::distance(&fmt1[0], &f)};

tests/installation_tests/find/CMakeLists.txt

@@ -17,10 +17,10 @@ file(WRITE main.cpp "
 #include <iostream>
 
 int main() {
-    const std::string input =  \"3.1416 xyz \";
+    std::string input = \"3.1416 xyz \";
     double result;
     auto answer = fast_float::from_chars(input.data(), input.data()+input.size(), result);
-    if(answer.ec != std::errc()) { std::cerr << \"parsing failure\\n\"; return EXIT_FAILURE; }
+    if (answer.ec != std::errc()) { std::cerr << \"parsing failure\\n\"; return EXIT_FAILURE; }
     std::cout << \"parsed the number \" << result << std::endl;
     return EXIT_SUCCESS;
 }")

tests/json_fmt.cpp

@@ -2,16 +2,14 @@
 #include <cstdlib>
 #include <iostream>
 #include <vector>
-
-// test that this option is ignored
-#define FASTFLOAT_ALLOWS_LEADING_PLUS
-
 #include "fast_float/fast_float.h"
 
 int main_readme() {
-  const std::string input = "+.1"; // not valid
+  std::string const input = "+.1"; // not valid
   double result;
-  fast_float::parse_options options{fast_float::chars_format::json};
+  fast_float::parse_options options{
+      fast_float::chars_format::json |
+      fast_float::chars_format::allow_leading_plus}; // should be ignored
   auto answer = fast_float::from_chars_advanced(
       input.data(), input.data() + input.size(), result, options);
   if (answer.ec == std::errc()) {
@@ -22,9 +20,11 @@ int main_readme() {
 }
 
 int main_readme2() {
-  const std::string input = "inf"; // not valid in JSON
+  std::string const input = "inf"; // not valid in JSON
   double result;
-  fast_float::parse_options options{fast_float::chars_format::json};
+  fast_float::parse_options options{
+      fast_float::chars_format::json |
+      fast_float::chars_format::allow_leading_plus}; // should be ignored
   auto answer = fast_float::from_chars_advanced(
       input.data(), input.data() + input.size(), result, options);
   if (answer.ec == std::errc()) {
@@ -35,10 +35,12 @@ int main_readme2() {
 }
 
 int main_readme3() {
-  const std::string input =
+  std::string const input =
       "inf"; // not valid in JSON but we allow it with json_or_infnan
   double result;
-  fast_float::parse_options options{fast_float::chars_format::json_or_infnan};
+  fast_float::parse_options options{
+      fast_float::chars_format::json_or_infnan |
+      fast_float::chars_format::allow_leading_plus}; // should be ignored
   auto answer = fast_float::from_chars_advanced(
       input.data(), input.data() + input.size(), result, options);
   if (answer.ec != std::errc() || (!std::isinf(result))) {
@@ -52,6 +54,7 @@ struct ExpectedResult {
   double value;
   std::string junk_chars;
 };
+
 struct AcceptedValue {
   std::string input;
   ExpectedResult expected;
@@ -61,13 +64,14 @@ struct RejectReason {
   fast_float::parse_error error;
   intptr_t location_offset;
 };
+
 struct RejectedValue {
   std::string input;
   RejectReason reason;
 };
 
 int main() {
-  const std::vector<AcceptedValue> accept{
+  std::vector<AcceptedValue> const accept{
       {"-0.2", {-0.2, ""}},
       {"0.02", {0.02, ""}},
       {"0.002", {0.002, ""}},
@@ -76,7 +80,7 @@ int main() {
       {"1e", {1., "e"}},
       {"1e+", {1., "e+"}},
       {"inf", {std::numeric_limits<double>::infinity(), ""}}};
-  const std::vector<RejectedValue> reject{
+  std::vector<RejectedValue> const reject{
       {"-.2", {fast_float::parse_error::missing_integer_after_sign, 1}},
       {"00.02", {fast_float::parse_error::leading_zeros_in_integer_part, 0}},
       {"0.e+1", {fast_float::parse_error::no_digits_in_fractional_part, 2}},
@@ -90,8 +94,8 @@ int main() {
       {"nan(snan)", {fast_float::parse_error::no_digits_in_integer_part, 0}}};
 
   for (std::size_t i = 0; i < accept.size(); ++i) {
-    const auto &s = accept[i].input;
-    const auto &expected = accept[i].expected;
+    auto const &s = accept[i].input;
+    auto const &expected = accept[i].expected;
     double result;
     auto answer =
         fast_float::from_chars(s.data(), s.data() + s.size(), result,
@@ -114,7 +118,7 @@ int main() {
   }
 
   for (std::size_t i = 0; i < reject.size(); ++i) {
-    const auto &s = reject[i].input;
+    auto const &s = reject[i].input;
     double result;
     auto answer = fast_float::from_chars(s.data(), s.data() + s.size(), result,
                                          fast_float::chars_format::json);
@@ -125,11 +129,13 @@ int main() {
   }
 
   for (std::size_t i = 0; i < reject.size(); ++i) {
-    const auto &f = reject[i].input;
-    const auto &expected_reason = reject[i].reason;
-    auto answer = fast_float::parse_number_string(
+    auto const &f = reject[i].input;
+    auto const &expected_reason = reject[i].reason;
+    auto answer = fast_float::parse_number_string<true>(
         f.data(), f.data() + f.size(),
-        fast_float::parse_options(fast_float::chars_format::json));
+        fast_float::parse_options(
+            fast_float::chars_format::json |
+            fast_float::chars_format::allow_leading_plus)); // should be ignored
     if (answer.valid) {
       std::cerr << "json parse accepted invalid json " << f << std::endl;
       return EXIT_FAILURE;
@@ -154,6 +160,11 @@ int main() {
   if (main_readme2() != EXIT_SUCCESS) {
     return EXIT_FAILURE;
   }
+#ifndef __FAST_MATH__
+  if (main_readme3() != EXIT_SUCCESS) {
+    return EXIT_FAILURE;
+  }
+#endif
 
   return EXIT_SUCCESS;
 }

tests/long_exhaustive32.cpp

@@ -25,7 +25,7 @@ void allvalues() {
     memcpy(&v, &word, sizeof(v));
 
     {
-      const char *string_end = to_string(v, buffer);
+      char const *string_end = to_string(v, buffer);
       float result_value;
       auto result = fast_float::from_chars(buffer, string_end, result_value);
       // Starting with version 4.0 for fast_float, we return result_out_of_range

tests/long_exhaustive32_64.cpp

@@ -24,7 +24,7 @@ void all_32bit_values() {
     double v = v32;
 
     {
-      const char *string_end = to_string(v, buffer);
+      char const *string_end = to_string(v, buffer);
       double result_value;
       auto result = fast_float::from_chars(buffer, string_end, result_value);
       // Starting with version 4.0 for fast_float, we return result_out_of_range

tests/long_random64.cpp

@@ -53,7 +53,7 @@ void random_values(size_t N) {
     double v;
     memcpy(&v, &word, sizeof(v));
     {
-      const char *string_end = to_string(v, buffer);
+      char const *string_end = to_string(v, buffer);
       double result_value;
       auto result = fast_float::from_chars(buffer, string_end, result_value);
       // Starting with version 4.0 for fast_float, we return result_out_of_range

tests/long_test.cpp

@@ -19,8 +19,8 @@ template <typename T> bool test() {
                       "2.71828182845904523536028747135266249775724709369995";
   std::vector<T> answers = {T(0.15625), T(3.141592653589793),
                             T(2.718281828459045)};
-  const char *begin = input.data();
-  const char *end = input.data() + input.size();
+  char const *begin = input.data();
+  char const *end = input.data() + input.size();
   for (size_t i = 0; i < answers.size(); i++) {
     T result_value;
     while ((begin < end) && (std::isspace(*begin))) {

tests/p2497.cpp

@@ -0,0 +1,16 @@
+#include "fast_float/fast_float.h"
+
+#include <iostream>
+#include <string>
+
+int main() {
+  std::string input = "3.1416 xyz ";
+  double result;
+  if (auto answer = fast_float::from_chars(
+          input.data(), input.data() + input.size(), result)) {
+    std::cout << "parsed the number " << result << std::endl;
+    return EXIT_SUCCESS;
+  }
+  std::cerr << "failed to parse " << result << std::endl;
+  return EXIT_FAILURE;
+}

tests/powersoffive_hardround.cpp

@@ -15,8 +15,9 @@
 // always use this fallback because we cannot rely on it behaving as normal
 // gcc.
 #include <locale>
+
 // workaround for CYGWIN
-double cygwin_strtod_l(const char *start, char **end) {
+double cygwin_strtod_l(char const *start, char **end) {
   double d;
   std::stringstream ss;
   ss.imbue(std::locale::classic());
@@ -32,7 +33,8 @@ double cygwin_strtod_l(const char *start, char **end) {
   *end = const_cast<char *>(start) + nread;
   return d;
 }
-float cygwin_strtof_l(const char *start, char **end) {
+
+float cygwin_strtof_l(char const *start, char **end) {
   float d;
   std::stringstream ss;
   ss.imbue(std::locale::classic());
@@ -50,7 +52,7 @@ float cygwin_strtof_l(const char *start, char **end) {
 }
 #endif
 
-std::pair<double, bool> strtod_from_string(const char *st) {
+std::pair<double, bool> strtod_from_string(char const *st) {
   double d;
   char *pr;
 #if defined(__CYGWIN__) || defined(__MINGW32__) || defined(__MINGW64__) ||     \

tests/random64.cpp

@@ -56,7 +56,7 @@ void random_values(size_t N) {
     memcpy(&v, &word, sizeof(v));
     // if (!std::isnormal(v))
     {
-      const char *string_end = to_string(v, buffer);
+      char const *string_end = to_string(v, buffer);
       double result_value;
       auto result = fast_float::from_chars(buffer, string_end, result_value);
       // Starting with version 4.0 for fast_float, we return result_out_of_range

tests/random_string.cpp

@@ -14,8 +14,9 @@
 // gcc.
 #include <locale>
 #include <sstream>
+
 // workaround for CYGWIN
-double cygwin_strtod_l(const char *start, char **end) {
+double cygwin_strtod_l(char const *start, char **end) {
   double d;
   std::stringstream ss;
   ss.imbue(std::locale::classic());
@@ -31,7 +32,8 @@ double cygwin_strtod_l(const char *start, char **end) {
   *end = const_cast<char *>(start) + nread;
   return d;
 }
-float cygwin_strtof_l(const char *start, char **end) {
+
+float cygwin_strtof_l(char const *start, char **end) {
   float d;
   std::stringstream ss;
   ss.imbue(std::locale::classic());
@@ -53,6 +55,7 @@ class RandomEngine {
 public:
   RandomEngine() = delete;
   RandomEngine(uint64_t new_seed) : wyhash64_x_(new_seed){};
+
   uint64_t next() {
     // Adapted from https://github.com/wangyi-fudan/wyhash/blob/master/wyhash.h
     // Inspired from
@@ -65,9 +68,13 @@ public:
     uint64_t m2 = (tmp.high) ^ tmp.low;
     return m2;
   }
+
   bool next_bool() { return (next() & 1) == 1; }
+
   int next_int() { return static_cast<int>(next()); }
+
   char next_char() { return static_cast<char>(next()); }
+
   double next_double() { return static_cast<double>(next()); }
 
   int next_ranged_int(int min, int max) { // min and max are included
@@ -90,6 +97,7 @@ public:
     }
     return int(m.high) + min;
   }
+
   int next_digit() { return next_ranged_int(0, 9); }
 
 private:

tests/rcppfastfloat_test.cpp

@@ -2,91 +2,70 @@
  * See https://github.com/eddelbuettel/rcppfastfloat/issues/4
  */
 
-#define FASTFLOAT_ALLOWS_LEADING_PLUS 1
-#define FASTFLOAT_SKIP_WHITE_SPACE 1 // important !
 #include "fast_float/fast_float.h"
 #include <iostream>
 #include <string>
 #include <vector>
 
+struct test_data {
+  std::string input;
+  bool expected_success;
+  double expected_result;
+};
+
 bool eddelbuettel() {
-  std::vector<std::string> inputs = {"infinity",
-                                     " \r\n\t\f\v3.16227766016838 \r\n\t\f\v",
-                                     " \r\n\t\f\v3 \r\n\t\f\v",
-                                     "  1970-01-01",
-                                     "-NaN",
-                                     "-inf",
-                                     " \r\n\t\f\v2.82842712474619 \r\n\t\f\v",
-                                     "nan",
-                                     " \r\n\t\f\v2.44948974278318 \r\n\t\f\v",
-                                     "Inf",
-                                     " \r\n\t\f\v2 \r\n\t\f\v",
-                                     "-infinity",
-                                     " \r\n\t\f\v0 \r\n\t\f\v",
-                                     " \r\n\t\f\v1.73205080756888 \r\n\t\f\v",
-                                     " \r\n\t\f\v1 \r\n\t\f\v",
-                                     " \r\n\t\f\v1.4142135623731 \r\n\t\f\v",
-                                     " \r\n\t\f\v2.23606797749979 \r\n\t\f\v",
-                                     "1970-01-02  ",
-                                     " \r\n\t\f\v2.64575131106459 \r\n\t\f\v",
-                                     "inf",
-                                     "-nan",
-                                     "NaN",
-                                     "",
-                                     "-Inf",
-                                     "+2.2",
-                                     "1d+4",
-                                     "1d-1",
-                                     "0.",
-                                     "-.1",
-                                     "+.1",
-                                     "1e+1",
-                                     "+1e1"};
-  std::vector<std::pair<bool, double>> expected_results = {
-      {true, std::numeric_limits<double>::infinity()},
-      {true, 3.16227766016838},
-      {true, 3},
-      {false, -1},
-      {true, std::numeric_limits<double>::quiet_NaN()},
-      {true, -std::numeric_limits<double>::infinity()},
-      {true, 2.82842712474619},
-      {true, std::numeric_limits<double>::quiet_NaN()},
-      {true, 2.44948974278318},
-      {true, std::numeric_limits<double>::infinity()},
-      {true, 2},
-      {true, -std::numeric_limits<double>::infinity()},
-      {true, 0},
-      {true, 1.73205080756888},
-      {true, 1},
-      {true, 1.4142135623731},
-      {true, 2.23606797749979},
-      {false, -1},
-      {true, 2.64575131106459},
-      {true, std::numeric_limits<double>::infinity()},
-      {true, std::numeric_limits<double>::quiet_NaN()},
-      {true, std::numeric_limits<double>::quiet_NaN()},
-      {false, -1},
-      {true, -std::numeric_limits<double>::infinity()},
-      {true, 2.2},
-      {false, -1},
-      {false, -1},
-      {true, 0},
-      {true, -0.1},
-      {true, 0.1},
-      {true, 10},
-      {true, 10},
+  std::vector<test_data> const test_datas = {
+      {"infinity", true, std::numeric_limits<double>::infinity()},
+      {" \r\n\t\f\v3.16227766016838 \r\n\t\f\v", true, 3.16227766016838},
+      {" \r\n\t\f\v3 \r\n\t\f\v", true, 3.0},
+      {"  1970-01-01", false, 0.0},
+      {"-NaN", true, std::numeric_limits<double>::quiet_NaN()},
+      {"-inf", true, -std::numeric_limits<double>::infinity()},
+      {" \r\n\t\f\v2.82842712474619 \r\n\t\f\v", true, 2.82842712474619},
+      {"nan", true, std::numeric_limits<double>::quiet_NaN()},
+      {" \r\n\t\f\v2.44948974278318 \r\n\t\f\v", true, 2.44948974278318},
+      {"Inf", true, std::numeric_limits<double>::infinity()},
+      {" \r\n\t\f\v2 \r\n\t\f\v", true, 2.0},
+      {"-infinity", true, -std::numeric_limits<double>::infinity()},
+      {" \r\n\t\f\v0 \r\n\t\f\v", true, 0.0},
+      {" \r\n\t\f\v1.73205080756888 \r\n\t\f\v", true, 1.73205080756888},
+      {" \r\n\t\f\v1 \r\n\t\f\v", true, 1.0},
+      {" \r\n\t\f\v1.4142135623731 \r\n\t\f\v", true, 1.4142135623731},
+      {" \r\n\t\f\v2.23606797749979 \r\n\t\f\v", true, 2.23606797749979},
+      {"1970-01-02  ", false, 0.0},
+      {" \r\n\t\f\v2.64575131106459 \r\n\t\f\v", true, 2.64575131106459},
+      {"inf", true, std::numeric_limits<double>::infinity()},
+      {"-nan", true, std::numeric_limits<double>::quiet_NaN()},
+      {"NaN", true, std::numeric_limits<double>::quiet_NaN()},
+      {"", false, 0.0},
+      {"-Inf", true, -std::numeric_limits<double>::infinity()},
+      {"+2.2", true, 2.2},
+      {"1d+4", false, 0.0},
+      {"1d-1", false, 0.0},
+      {"0.", true, 0.0},
+      {"-.1", true, -0.1},
+      {"+.1", true, 0.1},
+      {"1e+1", true, 10.0},
+      {"+1e1", true, 10.0},
+      {"-+0", false, 0.0},
+      {"-+inf", false, 0.0},
+      {"-+nan", false, 0.0},
   };
-  for (size_t i = 0; i < inputs.size(); i++) {
-    const std::string &input = inputs[i];
-    std::pair<bool, double> expected = expected_results[i];
+  for (size_t i = 0; i < test_datas.size(); i++) {
+    auto const &input = test_datas[i].input;
+    auto const expected_success = test_datas[i].expected_success;
+    auto const expected_result = test_datas[i].expected_result;
     double result;
     // answer contains a error code and a pointer to the end of the
     // parsed region (on success).
-    auto answer = fast_float::from_chars(input.data(),
-                                         input.data() + input.size(), result);
+    auto const answer = fast_float::from_chars(
+        input.data(), input.data() + input.size(), result,
+        fast_float::chars_format::general |
+            fast_float::chars_format::allow_leading_plus |
+            fast_float::chars_format::skip_white_space);
     if (answer.ec != std::errc()) {
       std::cout << "could not parse" << std::endl;
-      if (expected.first) {
+      if (expected_success) {
         return false;
       }
       continue;
@@ -94,9 +73,9 @@ bool eddelbuettel() {
     bool non_space_trailing_content = false;
     if (answer.ptr != input.data() + input.size()) {
       // check that there is no content left
-      for (const char *leftover = answer.ptr;
+      for (char const *leftover = answer.ptr;
            leftover != input.data() + input.size(); leftover++) {
-        if (!fast_float::is_space(uint8_t(*leftover))) {
+        if (!fast_float::is_space(*leftover)) {
           non_space_trailing_content = true;
           break;
         }
@@ -104,24 +83,19 @@ bool eddelbuettel() {
     }
     if (non_space_trailing_content) {
       std::cout << "found trailing content " << std::endl;
-    }
-
-    if (non_space_trailing_content) {
-      if (!expected.first) {
+      if (!expected_success) {
         continue;
       } else {
         return false;
       }
     }
     std::cout << "parsed " << result << std::endl;
-    if (!expected.first) {
+    if (!expected_success) {
       return false;
     }
-    if (result != expected.second) {
-      if (std::isnan(result) && std::isnan(expected.second)) {
-        continue;
-      }
-      std::cout << "results do not match. Expected " << expected.second
+    if (result != expected_result &&
+        !(std::isnan(result) && std::isnan(expected_result))) {
+      std::cout << "results do not match. Expected " << expected_result
                 << std::endl;
       return false;
     }

tests/short_random_string.cpp

@@ -14,8 +14,9 @@
 // gcc.
 #include <locale>
 #include <sstream>
+
 // workaround for CYGWIN
-double cygwin_strtod_l(const char *start, char **end) {
+double cygwin_strtod_l(char const *start, char **end) {
   double d;
   std::stringstream ss;
   ss.imbue(std::locale::classic());
@@ -31,7 +32,8 @@ double cygwin_strtod_l(const char *start, char **end) {
   *end = const_cast<char *>(start) + nread;
   return d;
 }
-float cygwin_strtof_l(const char *start, char **end) {
+
+float cygwin_strtof_l(char const *start, char **end) {
   float d;
   std::stringstream ss;
   ss.imbue(std::locale::classic());
@@ -53,6 +55,7 @@ class RandomEngine {
 public:
   RandomEngine() = delete;
   RandomEngine(uint64_t new_seed) : wyhash64_x_(new_seed){};
+
   uint64_t next() {
     // Adapted from https://github.com/wangyi-fudan/wyhash/blob/master/wyhash.h
     // Inspired from
@@ -65,9 +68,13 @@ public:
     uint64_t m2 = (tmp.high) ^ tmp.low;
     return m2;
   }
+
   bool next_bool() { return (next() & 1) == 1; }
+
   int next_int() { return static_cast<int>(next()); }
+
   char next_char() { return static_cast<char>(next()); }
+
   double next_double() { return static_cast<double>(next()); }
 
   int next_ranged_int(int min, int max) { // min and max are included
@@ -90,6 +97,7 @@ public:
     }
     return int(m.high) + min;
   }
+
   int next_digit() { return next_ranged_int(0, 9); }
 
 private:

tests/string_test.cpp

@@ -16,8 +16,9 @@
 // gcc.
 #include <locale>
 #include <sstream>
+
 // workaround for CYGWIN
-double cygwin_strtod_l(const char *start, char **end) {
+double cygwin_strtod_l(char const *start, char **end) {
   double d;
   std::stringstream ss;
   ss.imbue(std::locale::classic());
@@ -33,7 +34,8 @@ double cygwin_strtod_l(const char *start, char **end) {
   *end = const_cast<char *>(start) + nread;
   return d;
 }
-float cygwin_strtof_l(const char *start, char **end) {
+
+float cygwin_strtof_l(char const *start, char **end) {
   float d;
   std::stringstream ss;
   ss.imbue(std::locale::classic());
@@ -93,8 +95,8 @@ template <typename T> bool test() {
                                         std::errc(),
                                         std::errc(),
                                         std::errc()};
-  const char *begin = input.data();
-  const char *end = input.data() + input.size();
+  char const *begin = input.data();
+  char const *end = input.data() + input.size();
   for (size_t i = 0; i < answers.size(); i++) {
     T result_value;
     while ((begin < end) && (std::isspace(*begin))) {
@@ -120,9 +122,9 @@ template <typename T> bool test() {
   return true;
 }
 
-template <typename T> void strtod_from_string(const std::string &st, T &d);
+template <typename T> void strtod_from_string(std::string const &st, T &d);
 
-template <> void strtod_from_string(const std::string &st, double &d) {
+template <> void strtod_from_string(std::string const &st, double &d) {
   char *pr = (char *)st.c_str();
 #if defined(__CYGWIN__) || defined(__MINGW32__) || defined(__MINGW64__) ||     \
     defined(sun) || defined(__sun)
@@ -139,7 +141,7 @@ template <> void strtod_from_string(const std::string &st, double &d) {
   }
 }
 
-template <> void strtod_from_string(const std::string &st, float &d) {
+template <> void strtod_from_string(std::string const &st, float &d) {
   char *pr = (char *)st.c_str();
 #if defined(__CYGWIN__) || defined(__MINGW32__) || defined(__MINGW64__) ||     \
     defined(sun) || defined(__sun)
@@ -160,7 +162,7 @@ template <typename T> bool partow_test() {
   // credit:
   // https://github.com/ArashPartow/strtk/blob/master/strtk_tokenizer_cmp.cpp#L568
   // MIT license
-  const std::string strint_list[] = {
+  std::string const strint_list[] = {
       "9007199254740993",
       "9007199254740994",
       "9007199254740995",
@@ -1085,7 +1087,7 @@ template <typename T> bool partow_test() {
       "1234567890",
       "-1234567890",
   };
-  for (const std::string &st : strint_list) {
+  for (std::string const &st : strint_list) {
     T expected_value;
     strtod_from_string(st, expected_value);
     T result_value;

tests/supported_chars_test.cpp

@@ -0,0 +1,53 @@
+#include "fast_float/fast_float.h"
+#include <iostream>
+#include <string>
+#include <system_error>
+
+template <typename UC> bool test(std::string s, double expected) {
+  std::basic_string<UC> input(s.begin(), s.end());
+  double result;
+  auto answer =
+      fast_float::from_chars(input.data(), input.data() + input.size(), result);
+  if (answer.ec != std::errc()) {
+    std::cerr << "parsing of \"" << s << "\" should succeed\n";
+    return false;
+  }
+  if (result != expected && !(std::isnan(result) && std::isnan(expected))) {
+    std::cerr << "parsing of \"" << s << "\" succeeded, expected " << expected
+              << " got " << result << "\n";
+    return false;
+  }
+  return true;
+}
+
+int main() {
+  if (!test<char>("4.2", 4.2)) {
+    std::cout << "test failure for char" << std::endl;
+    return EXIT_FAILURE;
+  }
+
+  if (!test<wchar_t>("4.2", 4.2)) {
+    std::cout << "test failure for wchar_t" << std::endl;
+    return EXIT_FAILURE;
+  }
+
+#ifdef __cpp_char8_t
+  if (!test<char8_t>("4.2", 4.2)) {
+    std::cout << "test failure for char8_t" << std::endl;
+    return EXIT_FAILURE;
+  }
+#endif
+
+  if (!test<char16_t>("4.2", 4.2)) {
+    std::cout << "test failure for char16_t" << std::endl;
+    return EXIT_FAILURE;
+  }
+
+  if (!test<char32_t>("4.2", 4.2)) {
+    std::cout << "test failure for char32_t" << std::endl;
+    return EXIT_FAILURE;
+  }
+
+  std::cout << "all ok" << std::endl;
+  return EXIT_SUCCESS;
+}

tests/wide_char_test.cpp

@@ -0,0 +1,57 @@
+#include "fast_float/fast_float.h"
+#include <iostream>
+#include <string>
+#include <system_error>
+
+bool tester(std::string s, double expected,
+            fast_float::chars_format fmt = fast_float::chars_format::general) {
+  std::wstring input(s.begin(), s.end());
+  double result;
+  auto answer = fast_float::from_chars(
+      input.data(), input.data() + input.size(), result, fmt);
+  if (answer.ec != std::errc()) {
+    std::cerr << "parsing of \"" << s << "\" should succeed\n";
+    return false;
+  }
+  if (result != expected && !(std::isnan(result) && std::isnan(expected))) {
+    std::cerr << "parsing of \"" << s << "\" succeeded, expected " << expected
+              << " got " << result << "\n";
+    return false;
+  }
+  input[0] += 256;
+  answer = fast_float::from_chars(input.data(), input.data() + input.size(),
+                                  result, fmt);
+  if (answer.ec == std::errc()) {
+    std::cerr << "parsing of altered \"" << s << "\" should fail\n";
+    return false;
+  }
+  return true;
+}
+
+bool test_minus() { return tester("-42", -42); }
+
+bool test_plus() {
+  return tester("+42", 42,
+                fast_float::chars_format::general |
+                    fast_float::chars_format::allow_leading_plus);
+}
+
+bool test_space() {
+  return tester(" 42", 42,
+                fast_float::chars_format::general |
+                    fast_float::chars_format::skip_white_space);
+}
+
+bool test_nan() {
+  return tester("nan", std::numeric_limits<double>::quiet_NaN());
+}
+
+int main() {
+  if (test_minus() && test_plus() && test_space() && test_nan()) {
+    std::cout << "all ok" << std::endl;
+    return EXIT_SUCCESS;
+  }
+
+  std::cout << "test failure" << std::endl;
+  return EXIT_FAILURE;
+}