C++ Format
dragonbox
Our great sponsors
C++ Format | dragonbox | |
---|---|---|
161 | 9 | |
19,147 | 486 | |
1.5% | - | |
9.8 | 8.2 | |
4 days ago | 10 days ago | |
C++ | C++ | |
GNU General Public License v3.0 or later | Apache License 2.0 |
Stars - the number of stars that a project has on GitHub. Growth - month over month growth in stars.
Activity is a relative number indicating how actively a project is being developed. Recent commits have higher weight than older ones.
For example, an activity of 9.0 indicates that a project is amongst the top 10% of the most actively developed projects that we are tracking.
C++ Format
-
C++ Game Utility Libraries: for Game Dev Rustaceans
GitHub repo: fmtlib/fmt
-
Creating k-NN with C++ (from Scratch)
cmake_minimum_required(VERSION 3.5) project(knn_cpp CXX) # Set up C++ version and properties include(CheckIncludeFileCXX) check_include_file_cxx(any HAS_ANY) check_include_file_cxx(string_view HAS_STRING_VIEW) check_include_file_cxx(coroutine HAS_COROUTINE) set(CMAKE_CXX_STANDARD 20) set(CMAKE_BUILD_TYPE Debug) set(CMAKE_CXX_STANDARD_REQUIRED ON) set(CMAKE_CXX_EXTENSIONS OFF) # Copy data file to build directory file(COPY ${CMAKE_CURRENT_SOURCE_DIR}/iris.data DESTINATION ${CMAKE_CURRENT_BINARY_DIR}) # Download library usinng FetchContent include(FetchContent) FetchContent_Declare(matplotplusplus GIT_REPOSITORY https://github.com/alandefreitas/matplotplusplus GIT_TAG origin/master) FetchContent_GetProperties(matplotplusplus) if(NOT matplotplusplus_POPULATED) FetchContent_Populate(matplotplusplus) add_subdirectory(${matplotplusplus_SOURCE_DIR} ${matplotplusplus_BINARY_DIR} EXCLUDE_FROM_ALL) endif() FetchContent_Declare( fmt GIT_REPOSITORY https://github.com/fmtlib/fmt.git GIT_TAG 7.1.3 # Adjust the version as needed ) FetchContent_MakeAvailable(fmt) # Add executable and link project libraries and folders add_executable(${PROJECT_NAME} main.cc) target_link_libraries(${PROJECT_NAME} PUBLIC matplot fmt::fmt) aux_source_directory(lib LIB_SRC) target_include_directories(${PROJECT_NAME} PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}) target_sources(${PROJECT_NAME} PRIVATE ${LIB_SRC}) add_subdirectory(tests)
-
Learn Modern C++
> This is from C++23, right?
std::println is, yes.
> I wonder how available this is within compilers
https://en.cppreference.com/w/cpp/compiler_support says clang, gcc, and msvc all support it, though I don't know how recent those versions are off the top of my head.
In my understanding, with this specific feature, if you want a polyfill for older compilers, or to use some more cutting-edge features that haven't been standardized yet, https://github.com/fmtlib/fmt is available to you.
-
The C++20 Naughty and Nice List for Game Devs
fmt/core.h has been heavily optimized for build speed and is usually faster to compile than equivalent iostream code: https://github.com/fmtlib/fmt?tab=readme-ov-file#compile-tim.... Once modularized std is available we might be able to be compete with printf.
-
For processing strings, streams in C++ can be slow
{fmt} has internal buffering but it's not yet exposed to users. There is a feature request for it: https://github.com/fmtlib/fmt/issues/2354. FILE buffering is not too bad but it can be easily optimized: https://www.zverovich.net/2020/08/04/optimal-file-buffer-siz....
If performance matters, write your own specialized string processing code which works on "raw" data in memory buffers. If convenience matters look at https://github.com/fmtlib/fmt (or std::format which AFAIK is less feature rich) and https://github.com/imageworks/pystring.
I like C much more than C++, but even I must say that https://github.com/fmtlib/fmt is pretty nice (which is the base for std::format). Together with pystring (https://github.com/imageworks/pystring) it makes string processing in C++ somewhat bearable (still slow though because pystring is based on std::string and excessively allocates, but at least convenient).
are currently a good example of pure product of the 9Xs/2000s when the hype about Object Oriented was ongoing.
Almost everything related to it has this OO code smell:
- Usage of virtual runtime dispatch with virtual calls when it is not necessary. Causing a negative impact on performance: a shame for C++.
- Heavy usage of function overloading with the "<<" operator. Leading to pages long compilation errors when an overload fails.
- Hidden states everywhere with the usage of state formatters and globals in the background.
- Unnecessary complexity with std::locale which is almost entirely useless for proper internationalisation.
- Useless encapsulation with error reports done as abstracted bit flags. Which is absolutely horrendous when dealing with file I/O: It hides away the underlying error with no proper way to access it.
- Deep class hierarchy making the entire thing looks like spaghetti.
- Useless abstraction with stringstream that hides the underlying buffer away, making it close to unusable on safety critical systems.
All of that made aged pretty badly, and for good reasons.
Fortunately there is an incoming way out of that with work of Viktor Zverovich on std::format and libfmt [1].
-
Codebases to read
Additionally, if you like low level stuff, check out libfmt (https://github.com/fmtlib/fmt) - not a big project, not difficult to understand. Or something like simdjson (https://github.com/simdjson/simdjson).
dragonbox
-
23 years into my career, I still love PHP and JavaScript
Apparently exact minimal float-to-string conversion is more recent than I thought, and many languages used to print more (Python?) or less (PHP) decimal digits than necessary to uniquely identify the bit pattern. Python correctly prints 46000.80 + 553.04 as 46553.840000000004, but I don't know if it ever prints more digits than needed. One recent algorithm for printing floats exactly is https://github.com/ulfjack/ryu, though I'm unaware what's the state-of-the-art (https://github.com/jk-jeon/dragonbox claims to be a benchmark and the best algorithm).
-
C++ I wrote a simple and fast formatting library for strings
A recent update to fmt was posted to r/cpp 3 days ago (https://www.reddit.com/r/cpp/comments/vrxkt0/fmt_90_released_with_improvements_to_floating/), and since that's still fresh on people's minds, they'll wonder how yours compares; and they'll probably wonder how it compares in terms of precision, round trip-ability, and performance of DragonBox https://github.com/jk-jeon/dragonbox. By "they", I probably mean "me" :D.
-
I created something much faster than a std::string
Existing fast and correct float-to-string implementations are out there. Just use them: https://github.com/jk-jeon/dragonbox. Or maybe use your stdlib if it has good support
-
How to read ascii files faster?
Parse floats faster with dragonbox
- Dragonbox 1.1.0 is released (a fast float-to-string conversion algorithm)
-
C++20 std::format is already std::regex 2.0 situation.
Even if what you say is true, it makes little sense to not reuse it. There are other concerns here and one of them is code size. But to address the performance issue, fmtlib is doing under 50ns for most fp numbers via dragonbox(https://github.com/jk-jeon/dragonbox has the chart). So still cpu bound, but all FP output is CPU bound. At this point, what prices are we trading for faster?
-
First release of dragonbox, a fast float-to-string conversion algorithm, is available
There are some benchmarks in https://github.com/jk-jeon/dragonbox#performance. TL;DR it's faster than other state of the art algorithms like Ryu, Schubfach and variations of Grisu. We saw a nice speed up when switching from Grisu3 to Dragonbox in {fmt}: https://github.com/fmtlib/fmt/pull/1882 and it has been improved even more since then.
What are some alternatives?
spdlog - Fast C++ logging library.
Better Enums - C++ compile-time enum to string, iteration, in a single header file
ZXing - ZXing ("Zebra Crossing") barcode scanning library for Java, Android
FastFormat - The fastest, most robust C++ formatting library
ZBar - Clone of the mercurial repository http://zbar.hg.sourceforge.net:8000/hgroot/zbar/zbar
fast_float - Fast and exact implementation of the C++ from_chars functions for number types: 4x to 10x faster than strtod, part of GCC 12 and WebKit/Safari
Scintilla
HTTP Parser - http request/response parser for c
Serial Communication Library - Cross-platform, Serial Port library written in C++
cxx-prettyprint - A header-only library for C++(0x) that allows automagic pretty-printing of any container.
compiler-explorer - Run compilers interactively from your web browser and interact with the assembly
Cppcheck - static analysis of C/C++ code