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https://github.com/ibireme/c_numconv_benchmark
C/C++ number ↔︎ string benchmark
https://github.com/ibireme/c_numconv_benchmark
atoi c conversion cpp dtoa itoa number performance strtod
Last synced: 7 days ago
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C/C++ number ↔︎ string benchmark
- Host: GitHub
- URL: https://github.com/ibireme/c_numconv_benchmark
- Owner: ibireme
- License: mit
- Created: 2020-10-14T15:02:03.000Z (about 4 years ago)
- Default Branch: master
- Last Pushed: 2024-08-26T17:10:03.000Z (3 months ago)
- Last Synced: 2024-08-26T20:15:16.015Z (3 months ago)
- Topics: atoi, c, conversion, cpp, dtoa, itoa, number, performance, strtod
- Language: C
- Homepage:
- Size: 4.03 MB
- Stars: 53
- Watchers: 8
- Forks: 5
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# Number Conversion Benchmark in C
This project evaluates the performance of functions that convert numbers to and from strings in C/C++.
The functions named `yy` is implemented by me, and used in the [yyjson](https://github.com/ibireme/yyjson) library.
# Requirement
- A modern compiler or IDE supporting C11 and C++17.
- CMake 3.14+ for building this project.
- Git for interacting with the submodule in this repository.
# Building
Clone this repository and initialize submodules:
```shell
git clone https://github.com/ibireme/c_numconv_benchmark.git
cd c_numconv_benchmark
git submodule update --init
```
Build and run:
```shell
mkdir build
cd build
cmake ..
cmake --build . --config Release
./run_itoa -o report_itoa.html
./run_atoi -o report_atoi.html
./run_dtoa -o report_dtoa.html
./run_strtod -o report_strtod.html
```
If you want to build with other compiler or IDE, try these commands:
```shell
# Clang for Linux/Unix:
cmake .. -DCMAKE_C_COMPILER=clang -DCMAKE_CXX_COMPILER=clang++
# Microsoft Visual Studio for Windows:
cmake .. -G "Visual Studio 16 2019" -A x64
cmake .. -G "Visual Studio 16 2019" -A Win32
# Xcode for macOS:
cmake .. -G Xcode
```
## Make the results more stable and accurate
This benchmark project uses `cpu cycle` for measurement, so `Turbo Boost` and similar technologies should be disabled to make the result more stable and accurate.
# Functions
-------
### Integer to String (itoa)
Function prototype:
```c
char *itoa_u32(uint32_t val, char *buf);
char *itoa_i32(int32_t val, char *buf);
char *itoa_u64(uint64_t val, char *buf);
char *itoa_i64(int64_t val, char *buf);
```
Click these links to see more reports with interactive charts:
* [clang_apple_m1](https://ibireme.github.io/c_numconv_benchmark/reports/clang_apple_m1/itoa.html)
* [clang_intel_i5_13600](https://ibireme.github.io/c_numconv_benchmark/reports/clang_intel_i5_13600/itoa.html)
* [gcc_intel_i5_13600](https://ibireme.github.io/c_numconv_benchmark/reports/gcc_intel_i5_13600/itoa.html)
* [msvc_intel_i5_13600](https://ibireme.github.io/c_numconv_benchmark/reports/msvc_intel_i5_13600/itoa.html)
-------
### String to Integer (atoi)
Function prototype:
```c
// Function prototype:
typedef enum {
atoi_result_suc = 0,
atoi_result_fail = 1,
atoi_result_overflow = 2,
} atoi_result;
uint32_t atoi_u32(const char *str, size_t len, char **endptr, atoi_result *res);
int32_t atoi_i32(const char *str, size_t len, char **endptr, atoi_result *res);
uint64_t atoi_u64(const char *str, size_t len, char **endptr, atoi_result *res);
int64_t atoi_i64(const char *str, size_t len, char **endptr, atoi_result *res);
```
Click these links to see more reports with interactive charts:
* [clang_apple_m1](https://ibireme.github.io/c_numconv_benchmark/reports/clang_apple_m1/atoi.html)
* [clang_intel_i5_13600](https://ibireme.github.io/c_numconv_benchmark/reports/clang_intel_i5_13600/atoi.html)
* [gcc_intel_i5_13600](https://ibireme.github.io/c_numconv_benchmark/reports/gcc_intel_i5_13600/atoi.html)
* [msvc_intel_i5_13600](https://ibireme.github.io/c_numconv_benchmark/reports/msvc_intel_i5_13600/atoi.html)
-------
### Double to String (dtoa)
Function prototype:
```c
// Function prototype:
char *dtoa(double val, char *buf);
```
Click these links to see more reports with interactive charts:
* [clang_apple_m1](https://ibireme.github.io/c_numconv_benchmark/reports/clang_apple_m1/dtoa.html)
* [clang_intel_i5_13600](https://ibireme.github.io/c_numconv_benchmark/reports/clang_intel_i5_13600/dtoa.html)
* [gcc_intel_i5_13600](https://ibireme.github.io/c_numconv_benchmark/reports/gcc_intel_i5_13600/dtoa.html)
* [msvc_intel_i5_13600](https://ibireme.github.io/c_numconv_benchmark/reports/msvc_intel_i5_13600/dtoa.html)
Note: the following functions may not generate shortest decimal representation, or may not remove the trailing zeros in fraction part:
* fpconv
* milo
* emyg
* erthink
-------
### String to Double (strtod)
Function prototype:
```c
// Function prototype:
double strtod(const char *str, size_t len, char **endptr);
```
Click these links to see more reports with interactive charts:
* [clang_apple_m1](https://ibireme.github.io/c_numconv_benchmark/reports/clang_apple_m1/strtod.html)
* [clang_intel_i5_13600](https://ibireme.github.io/c_numconv_benchmark/reports/clang_intel_i5_13600/strtod.html)
* [gcc_intel_i5_13600](https://ibireme.github.io/c_numconv_benchmark/reports/gcc_intel_i5_13600/strtod.html)
* [msvc_intel_i5_13600](https://ibireme.github.io/c_numconv_benchmark/reports/msvc_intel_i5_13600/strtod.html)
Note:
* `yy_fast` may returns inaccurate result with 0-2 ulp error in some cases.
* `ryu` and `lemire` may reject some integer numbers or large numbers.
-------
# Referenced libraries and articles
**Google (double <-> string)**
Efficient binary-decimal and decimal-binary conversion routines for IEEE doubles.
- (C++ library)
**Swift (double -> string)**
Convert double to string quickly and accurately in SwiftLang.
- (C code)
- (V1 discussion)
- (V2 discussion)
**David Gay (double <-> string)**
Widely used ANSI C implementations of strtod and dtoa.
- (C code)
**fmtlib (double -> string, integer -> string)**
A modern formatting library for C++.
- (C++ library)
- (Benchmark)
**abseil (double <-> string, integer <-> string)**
A C++ Common Libraries.
- (C++ library)
**ryu (double <-> string)**
Converts floating point numbers to decimal strings.
- (C library)
- (Talk)
- (Paper)
**Schubfach (doube -> string)**
The Schubfach way to render doubles by Raffaello Giulietti.
- (Paper)
- (Java implementation)
- (C++ implementation)
**dragonbox and grisu-exact (double -> string)**
Implementation of Dragonbox in C++.
- (C++ library and paper)
- (C++ library)
**fast_double_parser (string -> double)**
Fast function to parse strings into double by Daniel Lemire.
- (C++ library)
- (C++ library)
- (Talk)
- (Paper)
**itoa benchmark (integer -> string)**
C++ integer-to-string conversion benchmark
- (Benchmark)
**dtoa benchmark (double -> string)**
C++ double-to-string conversion benchmark
- (Benchmark)
**AppNexus (integer -> string)**
Print integers faster
- (Discussion)
- (Blog)
- (Code)
**benchmark (string -> integer)**
- (Blog)
- (Benchmark)
**benchmark (double -> string, integer -> string)**
- (Benchmark)
- (Benchmark)
# License
This project is distributed under the MIT license.