chfloat is a lightweight and superfast C++17 numeric parsing library.

Primary goal: provide a convenient, zero-allocation API for parsing float/double and integers from byte buffers.

Note: integers api is no optimized so far.

• Float/double parsing: chfloat::from_chars (pointer-range API)

  • Supports general format only
  • Supports specials: nan, inf, infinity (ASCII, case-insensitive)

• Integer parsing: chfloat::from_chars (base 2..36)

• Whitespace skipping variants: chfloat::from_chars_ws (ASCII-only leading whitespace)

• Small utility: chfloat::parse_digit

• Public API: include/chfloat/chfloat.h
• Tests: test/test_main.cpp
• Benchmarks: benchmark/benchmark_main.cpp
• Benchmark report output: report/benchmark.md

From repository root:

cmake -S chfloat -B chfloat/build -DCHFLOAT_BUILD_TESTS=ON -DCHFLOAT_BUILD_BENCHMARKS=ON
# For performance numbers, build Release:
cmake --build chfloat/build -j --config Release
ctest --test-dir chfloat/build

# Benchmark (writes report/benchmark.md relative to the current working dir)
cd chfloat
../chfloat/build/Release/chfloat_benchmark --n 100000 --iters 10

If you use Ninja (single-config):

cmake -S chfloat -B chfloat/buildn -G Ninja -DCHFLOAT_BUILD_TESTS=ON -DCHFLOAT_BUILD_BENCHMARKS=ON -DCMAKE_BUILD_TYPE=Release
cmake --build chfloat/buildn
cd chfloat
../chfloat/buildn/chfloat_benchmark --n 100000 --iters 10

#include <chfloat/chfloat.h>

double x = 0;
auto r = chfloat::from_chars("3.14", "3.14" + 4, x);

// r.ptr points one-past-the-last consumed character.
// r.ec is chfloat::errc::{ok, invalid_argument, result_out_of_range}.

int v = 0;
auto ri = chfloat::from_chars("42", "42" + 2, v);

• from_chars is strict (no leading whitespace). Use from_chars_ws if you want ASCII whitespace skipping.
• chars_format is currently accepted for API shape, but only chars_format::general is supported for floats.
• Locale is not used (ASCII only).

Environment:

• os: Windows 10.0.26100

• cpu: 12th Gen Intel(R) Core(TM) i9-12900K

• logical_cores: 24

• ram_total_gib: 31.7474

• C++: C++17

• Build: Release

• Compiler: MSVC _MSC_VER=1938

• Baselines: chfloat + std::strtod/strtof

• Comparison: fast_float

• Inputs: n=100000, iters=10

• Runs: 7 (median seconds)

• Inputs: n=100000, iters=10

• Runs: 7 (median seconds)

• Inputs: n=100000, iters=10

• Runs: 7 (median seconds)

Notes:

• Items/s counts parsed numbers; MB/s counts input bytes processed.
• This benchmark is single-threaded and measures throughput on this machine.
• The 'Stable' table reports median seconds across multiple runs.