# fast_io **Repository Path**: MacroModel/fast_io ## Basic Information - **Project Name**: fast_io - **Description**: fast_io是用C++20概念来实现的I/O库，用于取代iostream和stdio.h，比流和stdio.h至少快10倍。 - **Primary Language**: C++ - **License**: MIT - **Default Branch**: master - **Homepage**: https://bitbucket.org/ejsvifq_mabmip/fast_io - **GVP Project**: No ## Statistics - **Stars**: 0 - **Forks**: 17 - **Created**: 2023-03-29 - **Last Updated**: 2025-03-05 ## Categories & Tags **Categories**: Uncategorized **Tags**: None ## README # fast_io fast_io is a C++20 input/output library that provides [exceptional speed](readme.md#Benchmarks) and is designed to replace the commonly used `` and `` libraries. It is a header-only library and is licensed under the [MIT license](license.txt), making it easy to include in any project. However, it requires a C++20 compiler that supports concepts. *The original repository for fast_io has been archived due to git bloat over time, but older commits can still be found there.* *old commits were [here](https://bitbucket.org/ejsvifq_mabmip/fast_io_archive-2022-01-23).* ## Examples ### Print to `stdout` ```cpp #include int main() { print("Hello, fast_io world!\n"); } ``` ### Memory map file ```cpp #include int main() { fast_io::native_file_loader file_data("text.txt"); // file_data satisfies std::ranges::contiguous_range } ``` ### Other examples For other up-to-date examples, please look in the [`examples/`](examples/) folder. Deprecated examples are [here](https://bitbucket.org/ejsvifq_mabmip/fast_io_deprecated) but they might not work anymore. This i18n repo stores the i18n source files. [https://bitbucket.org/ejsvifq_mabmip/fast_io_i18n](https://bitbucket.org/ejsvifq_mabmip/fast_io_i18n) ## F.A.Q. ### What does "fast" mean in fast_io? The term ```fast``` in ```fast_io``` does not necessarily imply that it is the fastest input/output library available (as it would have been named as ```fastest_io``` instead). Instead, the term refers to the fact that ```fast_io``` is notably faster than `````` and `````` libraries in all cases. ### What are the supported platforms, compilers...? See [support.md](support.md) for a list of supported things and platform specific usage notes. ### Other questions? You can ask questions on the [fast_io discord server](https://discord.gg/wYfh8kk) or QQ group: `801441303`. ## Documentation See either https://ewindy.gitee.io/fast_io_rst/index.html or https://gitee.com/qabeowjbtkwb/fast_io/wikis. ## Features - As close to system call as possible. - Unicode support (UTF-8, UTF-16, UTF-32) + codecvt for GB18030 and UTF-EBCDIC (no libc correctly deals with it) - RAII for C `FILE*`, POSIX `fd` and win32/NT `HANDLE` - Interop with `` and `` - No easily misused stuff like `std::endl` - Static I/O manipulators instead of format strings. - Optional locale. - Stateless I/O manipulation. - Consistent error handling; when available, exceptions as the **only** error reporting mechanism (no `std::error_code`, `std::system_error` or useless bounds checking) - Freestanding mode. - Address Sanitizer special code for protecting memory safety issues. - Dynamic Instrumentation Support - Supports POSIX iconv. You can use fast_io for your coding conversion. - Binary serialization for trivially copyable types and standard containers - Plays well with C++ containers (e.g. `std::vector` is valid) - Basic/Lua/Python/etc format (print, scan). No support for C and C++ since they are security hazards. - Provide APIs to expose the internal implementation of `FILE*` and C++ streams. - Native Handle Interface - Extremely easy to support custom devices - C and C++ style compile time open mode parsing. - No `traits_type` and `EOF` - Dynamic Type Support - Multi Process - Memory mapping - debugging IO (optionally with GUI) - Round-trip floating point algorithm - Hash algorithms support: intrinsic SHA-1, intrinsic HMAC-SHA1, intrinsic SHA-256, intrinsic HMAC-SHA256, SHA-512, HMAC-SHA512 as well as non crypto hash algorithms, such as Jenkins Hash. - zlib compression/decompression - Filesystem - OpenSSL BIO, Qt QFile, MFC CFile support ### Post C++20 1. Module support 2. Coroutine support for async IO 3. Improve and refactor code once [Zero-overhead deterministic exceptions](http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2018/p0709r0.pdf) are added to the standard ## Benchmarks 1. I/O 10M integers Goal: Print out ten million integers from 0 to 10M to file. Then reopen that file to scan back. All benchmarks are in benchmarks/0000.10m_size_t/unit. Notice: I modified libstdc++'s BUFSIZ 1048576 due to BUFSIZ is too small (512 bytes) for MinGW-W64, or it performs horribly. | Platform | Windows |MinGW-W64 GCC 11.0.0 | MSVCRT + libstdc++ | |--------------------------------|-------------------------|-----------------------|------------------------------------------------------| | | | Method | Output time | Input time | Comment | |--------------------------------|-------------------------|-----------------------|------------------------------------------------------| | stdio.h(fprintf/fscanf) | 2.412987s | 5.607791s | | | fstream | 0.462012s | 1.192s | | | fstream with rdbuf.sputc trick | 0.33895s | 1.170173s | | | fast_io::i/obuf_file | 0.04903s | 0.080996s | | | fast_io::i/obuf_file_mutex | 0.146064s | 0.113155s | thread safe | | c_locale_i/obuf_file ("C") | 0.065988s | 0.086012s | imbued with locale, locale "C" | | c_locale_i/obuf_file local | 0.153995s | :x: | imbued with locale, locale "" | | fmt::format_int+obuf_file | 0.122999s | :x: | | | fmt::format_int+ofstream | 0.209055s | :x: | | | fmt::format+ofstream | 0.548s | :x: | fmt makes things slower | | fmt::print | 0.663996s | :x: | fmt makes things slower | | std::to_chars+obuf_file | 0.12s | :x: | | | std::to_chars+ofstream | 0.192s | :x: | | | fast_io::c_file_unlocked | 0.098999s | 0.126003s | I hacked MSVCRT's FILE* implementation | | fast_io::c_file | 0.298988s | 0.318001s | Thread Safe. I hacked MSVCRT's FILE* implementation | | fast_io::filebuf_file | 0.048999s | 0.081s | I hacked libstdc++'s streambuf/filebuf implementation| | fast_io::iobuf_utf8_file_char16| 0.124s | 0.112001s | UTF-16=>UTF-8 with SSE| | fast_io::iobuf_utf8_file_char32| 0.110999s | 0.111011s | UTF-32=>UTF-8 with SSE| | std::wofstream | 2.64s | 3.843735s | wofstream with std::locale codecvt. Extremely slow tbh.| | fast_io::wfilebuf_io_observer | 2.415692s | 2.497704s | wofstream with std::locale codecvt. This proves fstream can never get fixed.| | Rust language | 0.483s | :x: | RUST IS SLOW. Also Rust does not deal with locale. Think how bad it is. | | Rust itoa library 0.4.6 | > 0.165s | :x: | I ignored the `\n` part for it to ensure no bias. | Rust language is 10x slower than fast\_io. + binary bloat and itoa library is still extremely slow and usable for me. It is at least 3x slower than fast\_io. Run the same test on MSVC 19.26.28805. | Platform | Windows | MSVC 19.26.28805 | Install fmtlib wastes time of my life | |--------------------------------|-------------------------|-----------------------|------------------------------------------------------| | | | Method | Output time | Input time | Comment | |--------------------------------|-------------------------|-----------------------|------------------------------------------------------| | stdio.h(fprintf/fscanf) | 1.5353597s | 1.4157233s | | | fstream | 3.6350262s | 3.8420339s | | | fstream with rdbuf.sputc trick | 3.3735902s | 3.8145566s | | | fast_io::i/obuf_file | 0.0631433s | 0.1030554s | | | fast_io::i/obuf_file_mutex | 0.2190659s | 0.2485886s | thread safe | | std::to_chars+obuf_file | 0.1641641s | :x: | | | std::to_chars+ofstream | 0.5461922s | :x: | | | fast_io::c_file_unlocked | 0.1102575s | 0.2399757s | I hacked Universal CRT's FILE* implementation | | fast_io::c_file | 0.2034755s | 0.2621148s | Thread Safe. I hacked UCRT's FILE* implementation | | fast_io::filebuf_file | 0.126661s | 0.2378803s | I hacked MSVC STL's streambuf/filebuf implementation | Run the same test on GCC 11. glibc + libstdc++ | Platform | Linux | GCC 11.0.0 | glibc + libstdc++ | |--------------------------------|-------------------------|-----------------------|------------------------------------------------------| | | | Method | Output time | Input time | Comment | |--------------------------------|-------------------------|-----------------------|------------------------------------------------------| | stdio.h(fprintf/fscanf) | 0.532792935s | 0.591907111s | | | fstream with rdbuf.sputc trick | 0.318896068s | 0.429406415s | | | fast_io::i/obuf_file | 0.050300857s | 0.065372395s | | | fast_io::i/obuf_file_mutex | 0.05290654s | 0.083040518s | thread safe | | c_locale_i/obuf_file ("C") | 0.051939052s | 0.065820056s | imbued with locale, locale "C" | | c_locale_i/obuf_file local | 0.162406082s | :x: | imbued with locale, locale "" | | std::to_chars+obuf_file | 0.115453587s | :x: | | | fmt::format_int+obuf_file | 0.1183587s | :x: | | | fmt::format_int+ofstream | 0.195914384s | :x: | | | fmt::format+ofstream | 0.633590975s | :x: | fmt makes things slower | | fmt::print | 0.495270371s | :x: | fmt makes things slower | | boost::iostreams | 0.400906063s | 0.444717051s | Using boost iostreams does not make your code faster | | fast_io::c_file_unlocked | 0.060076723s | 0.073299716s | I hacked glibc's FILE* implementation | | fast_io::c_file | 0.092490191s | 0.104545535s | Thread Safe. I hacked glibc's FILE* implementation | | fast_io::filebuf_file | 0.052251608s | 0.06655806s | I hacked libstdc++'s streambuf/filebuf implementation| You can see fast_io can also boost the performance of existing facilities for 10x! Yes, it can even improve FILE* and fstream's performance for 10x depending on platforms since I use concepts to abstract them all. fmtlib actually slows down I/O performance. 2. Output 10M double in round-trip mode with Ryu algorithm We only perform this test for MSVC since only msvc's charconv implements it. Yes. fast_io defeats msvc's charconv for over 20% for running the same algorithm. All benchmarks are in benchmarks/0001.10m_double/charconv. Run the same test on MSVC 19.26.28805. | Platform | Windows | MSVC 19.26.28805 | | |--------------------------------|-------------------------|-----------------------|------------------------------------------------------| | | | Method | Output time | Comment | |--------------------------------|-------------------------|------------------------------------------------------------------------------| | i/obuf_file | 0.4653818s | | | charconv + obuf_file | 0.6011s | | 3. Raw I/O Performance All benchmarks are in benchmarks/0014.file_io/file_io. Output 100000000x "Hello World\n" Notice: I modified libstdc++'s std::filebuf's BUFSIZ to 1048576 due to BUFSIZ is too small (512 bytes) for MinGW-W64 or it performs horribly. | Platform | Windows |MinGW-W64 GCC 11.0.0 | MSVCRT + libstdc++ | |--------------------------------|-------------------------|-----------------------|------------------------------------------------------| | | | Method | Output time | Comment | |--------------------------------|-------------------------|------------------------------------------------------------------------------| | fwrite | 2.524001s | | | fstream | 1.013001s | | | fast_io::obuf_file | 0.437998s | | | fast_io::obuf_file_mutex | 1.371s |Thread safe | | fast_io::c_file_unlocked | 1.164997s |I hacked MSVCRT's FILE* implementation | | fast_io::c_file | 3.337945s |Thread Safe. I hacked MSVCRT's FILE* implementation. Need further optimization| | fast_io::filebuf_file | 0.467001s |I hacked libstdc++'s std::filebuf implementation | | Platform | Linux | GCC 11.0.0 | glibc + libstdc++ | |--------------------------------|-------------------------|-----------------------|------------------------------------------------------| | | | Method | Output time | Comment | |--------------------------------|-------------------------|------------------------------------------------------------------------------| | fwrite | 1.457288317s | | | fstream | 1.249783346s | | | fast_io::obuf_file | 0.494827134s | | | fast_io::obuf_file_mutex | 0.497138826s |Thread safe | | fast_io::c_file_unlocked | 0.687976666s |I hacked glibc's FILE* implementation | | fast_io::c_file | 0.910792697s |Thread Safe. I hacked glibc's FILE* implementation | | fast_io::filebuf_file | 0.526955039s |I hacked libstdc++'s std::filebuf implementation | | Platform | Windows | MSVC 19.26.28805 | UCRT + MSVC STL | |--------------------------------|-------------------------|-----------------------|------------------------------------------------------| | | | Method | Output time | Comment | |--------------------------------|-------------------------|------------------------------------------------------------------------------| | fwrite | 3.3139122s | | | fstream | 1.7184119s | | | fast_io::obuf_file | 0.7996034s | | | fast_io::obuf_file_mutex | 2.2949221s |Thread safe. It looks like std::mutex is horribly slow for MSVC STL. | | fast_io::c_file_unlocked | 1.2103924s |I hacked UCRT's FILE* implementation | | fast_io::c_file | 2.3604295s |Thread Safe. I hacked UCRT's FILE* implementation | | fast_io::filebuf_file | 1.2805368s |I hacked MSVC STL's std::filebuf implementation | 4. Binary Size Just use the benchmark in benchmarks/0014.file_io/file_io. Dude, you should avoid stream as plague tbh. It is not healthy. | Platform | Windows |MinGW-W64 GCC 11.0.0 | MSVCRT + libstdc++ + static compile | |--------------------------------|-------------------------|-----------------------|------------------------------------------------------| | | | Method | Binary Size | Comment | |--------------------------------|-------------------------|------------------------------------------------------------------------------| | fstream | 925KB |Use fstream is not good for your health since std::locale bloats your binary. | | fast_io::obuf_file | 155KB | | | fast_io::c_file_unlocked | 157KB |I hacked MSVCRT's FILE* implementation | | fast_io::c_file | 157KB |Thread Safe. I hacked MSVCRT's FILE* implementation | | fast_io::filebuf_file | 933KB |I hacked libstdc++'s std::filebuf implementation. C++ stream sucks | 5. Code Convert Generate 100000000 🚄 emojis by using the program in benchmarks/0020.utf/fill_nc.cc Benchmarks are in examples/0043.iconv Universal iconv. (UTF-8 to GB18030 as an example) iconv test: | Platform | Windows |MinGW-W64 GCC 11.0.0 | MSVCRT + libstdc++ | |--------------------------------|-------------------------|-----------------------|------------------------------------------------------| | | | Method | Elapsed time | Comment | |--------------------------------|-------------------------|------------------------------------------------------------------------------| | iconv command | 1.529s | | | universal.cc | 1.293s | use POSIX libiconv | UTF8->UTF16LE Benchmarks are in examples/0022.utf iconv test: | Platform | Windows |MinGW-W64 GCC 11.0.0 | MSVCRT + libstdc++ | |--------------------------------|-------------------------|-----------------------|------------------------------------------------------| | | | Method | Elapsed time | Comment | |--------------------------------|-------------------------|------------------------------------------------------------------------------| | iconv command | 0.967s | GNU iconv. No BOM which sucks | | utf8_file_to_utf16_file.cc | 0.498s | I use the SSE algorithms provided by the utf-utils project. | UTF8->UTF32LE Benchmarks are in examples/0022.utf iconv test: | Platform | Windows |MinGW-W64 GCC 11.0.0 | MSVCRT + libstdc++ | |--------------------------------|-------------------------|-----------------------|------------------------------------------------------| | | | Method | Elapsed time | Comment | |--------------------------------|-------------------------|------------------------------------------------------------------------------| | iconv command | 0.844s | GNU iconv. No BOM which sucks | | utf8_file_to_utf32_file.cc | 0.442s | I use the SSE algorithms provided by the utf-utils project. | ## Credits The creation and development of this project were made possible thanks to the valuable contributions of various open-source projects. While the code was not copied directly from these projects, I used them as references and re-implemented them to suit the specific purposes of this library. In some cases, integration issues arose that required modifications to the original code. I am grateful to these projects and their developers for their commitment to making their code open and accessible to the wider community. |Project | Url |-----------------|----------------------------------------- |Grisu-Exact |https://github.com/jk-jeon/Grisu-Exact |Ryu |https://github.com/ulfjack/ryu |SHA-Intrinsics |https://github.com/noloader/SHA-Intrinsics |SHA1 |https://github.com/vog/sha1 |UTF-utils |https://github.com/BobSteagall/utf_utils |jenkins-hash-java|https://github.com/vkandy/jenkins-hash-java |md5 |https://github.com/JieweiWei/md5 |ReactOS |https://github.com/reactos/reactos |dirent_h |https://github.com/win32ports/dirent_h |GNU C library |https://www.gnu.org/software/libc/ |GNU Newlib |https://sourceware.org/newlib/ |Dragonbox |https://github.com/jk-jeon/dragonbox |JEAIII |https://github.com/jeaiii/itoa |Crypto++ |https://github.com/weidai11/cryptopp |MyItoA |https://gitee.com/xjkp2283572185/MyStd