c4core is a library of low-level C++ utilities, written with low-latency projects in mind.
Some of the utilities provided by c4core have already equivalent functionality in the C++ standard, but they are provided as the existing C++ equivalent may be insufficient (eg, std::string_view), inefficient (eg, std::string), heavy (eg streams), or plainly unusable on some platforms/projects, (eg exceptions); some other utilities have equivalent under consideration for C++ standardisation; and yet some other utilities have (to my knowledge) no equivalent under consideration. Be that as it may, I've been using these utilities in this or similar forms for some years now, and I've found them incredibly useful in my projects. I'm packing these as a separate library, as all of my projects use it.
c4core is extensively unit-tested in Linux, Windows and MacOS. The tests cover x64, x86, arm, wasm (emscripten), aarch64, ppc64le and s390x architectures, and include analysing c4core with:
- valgrind
- clang-tidy
- clang sanitizers:
- memory
- address
- undefined behavior
- thread
- LGTM.com
c4core also works in bare-metal, as well as in RISC-V, and in LoongArch, but at the moment it's not easy to add automated tests to the CI, so for now these are not in the list of official architectures.
- c4core - C++ core utilities
- Obtaining c4core
- Using c4core in your project
- Quick tour
- Writeable string views: c4::substr and c4::csubstr
- Value <-> character interoperation
- String formatting and parsing
c4::span
andc4::blob
- Enums and enum symbols
- Bitmasks and bitmask symbols
- Base64 encoding / decoding
- Fuzzy float comparison
- Multi-platform / multi-compiler utilities
- Runtime assertions and error handling
- Memory allocation
- Mass initialization/construction/destruction
c4core uses git submodules. It is best to clone c4core with the --recursive
option:
# using --recursive makes sure git submodules are also cloned at the same time
git clone --recursive https://github.com/biojppm/c4core
If you ommit the --recursive
option, then after cloning you will have to
make git checkout the current version of the submodules, using git submodule init
followed by git submodule update
.
c4core can be built with cmake, or can be used header only. It can also be obtained through some package managers.
The recommended way to use c4core is by making it part of your project
by using add_subdirectory(${path_to_c4core_root})
in your
CMakeLists.txt. Doing this is not intrusive to your cmake project
because c4core is fast to build, also prefixes every cmake
variable with C4CORE_
. But more importantly, this will enable you to
compile c4core with the exact same compile settings used by your
project.
Here's a very quick complete example of setting up your project to use c4core as a cmake subproject:
project(foo)
add_subdirectory(c4core)
add_library(foo foo.cpp)
target_link_libraries(foo PUBLIC c4core) # that's it!
Note above that the call to target_link_libraries()
is using PUBLIC
linking. This is required to make sure the include directories from c4core
are transitively used by clients of foo
.
If you prefer to pick a single header to get you quickly going, there is an amalgamation tool which generates this header:
[user@host c4core]$ python tools/amalgamate.py -h
usage: amalgamate.py [-h] [--fastfloat | --no-fastfloat] [--stl | --no-stl] [output]
positional arguments:
output output file. defaults to stdout
options:
-h, --help show this help message and exit
--fastfloat enable fastfloat library. this is the default.
--no-fastfloat enable fastfloat library. the default is --fastfloat.
--stl enable stl interop. this is the default.
--no-stl enable stl interop. the default is --stl.
c4core is available through the following package managers:
All of the utilities in this library are under the namespace c4
; any
exposed macros use the prefix C4_
: eg C4_ASSERT()
.
See partial documentation in rapidyaml's doxygen docs.
Here: #include <c4/substr.hpp>
.
There is a useful quickstart sample in rapidyaml's doxygen docs.
Here: #include <c4/charconv.hpp>
// TODO: elaborate on the topics:
c4::digits_dec(), c4::read_dec(), c4::write_dec()
c4::digits_hex(), c4::read_hex(), c4::write_hex()
c4::digits_oct(), c4::read_oct(), c4::write_oct()
c4::digits_bin(), c4::read_bin(), c4::write_bin()
c4::utoa(), c4::atou()
c4::itoa(), c4::atoi()
c4::ftoa(), c4::atof()
c4::dtoa(), c4::atod()
c4::xtoa(), c4::atox()
c4::to_chars(), c4::from_chars()
c4::to_chars_sub()
c4::to_chars_first()
The charconv funcions above are very fast; even faster than C++'s fastest facility std::from_chars()
, std::to_chars()
. For continuous benchmark results, browse through c4core's github CI benchmark runs. For example, a benchmark run on Linux/g++11.2 shows that:
c4::to_chars()
can be expected to be roughly...- ~40% to 2x faster than
std::to_chars()
- ~10x-30x faster than
sprintf()
- ~50x-100x faster than a naive
stringstream::operator<<()
followed bystringstream::str()
- ~40% to 2x faster than
c4::from_chars()
can be expected to be roughly...- ~10%-30% faster than
std::from_chars()
- ~10x faster than
scanf()
- ~30x-50x faster than a naive
stringstream::str()
followed bystringstream::operator>>()
- ~10%-30% faster than
Here are the results:
Write throughput | Read throughput | ||
---|---|---|---|
write uint8_t |
MB/s | read uint8_t |
MB/s |
c4::to_chars<u8> |
526.86 | c4::from_chars<u8> |
163.06 |
std::to_chars<u8> |
379.03 | std::from_chars<u8> |
154.85 |
std::sprintf<u8> |
20.49 | std::scanf<u8> |
15.75 |
std::stringstream<u8> |
3.82 | std::stringstream<u8> |
3.83 |
write int8_t |
MB/s | read int8_t |
MB/s |
c4::to_chars<i8> |
599.98 | c4::from_chars<i8> |
184.20 |
std::to_chars<i8> |
246.32 | std::from_chars<i8> |
156.40 |
std::sprintf<i8> |
19.15 | std::scanf<i8> |
16.44 |
std::stringstream<i8> |
3.83 | std::stringstream<i8> |
3.89 |
write uint16_t |
MB/s | read uint16_t |
MB/s |
c4::to_chars<u16> |
486.40 | c4::from_chars<u16> |
349.48 |
std::to_chars<u16> |
454.24 | std::from_chars<u16> |
319.13 |
std::sprintf<u16> |
38.74 | std::scanf<u16> |
28.12 |
std::stringstream<u16> |
7.08 | std::stringstream<u16> |
6.73 |
write int16_t |
MB/s | read int16_t |
MB/s |
c4::to_chars<i16> |
507.44 | c4::from_chars<i16> |
282.95 |
std::to_chars<i16> |
297.49 | std::from_chars<i16> |
186.18 |
std::sprintf<i16> |
39.03 | std::scanf<i16> |
28.45 |
std::stringstream<i16> |
6.98 | std::stringstream<i16> |
6.49 |
write uint32_t |
MB/s | read uint32_t |
MB/s |
c4::to_chars<u32> |
730.12 | c4::from_chars<u32> |
463.95 |
std::to_chars<u32> |
514.76 | std::from_chars<u32> |
329.42 |
std::sprintf<u32> |
71.19 | std::scanf<u32> |
44.97 |
std::stringstream<u32> |
14.05 | std::stringstream<u32> |
12.57 |
write int32_t |
MB/s | read int32_t |
MB/s |
c4::to_chars<i32> |
618.76 | c4::from_chars<i32> |
345.53 |
std::to_chars<i32> |
394.72 | std::from_chars<i32> |
224.46 |
std::sprintf<i32> |
71.14 | std::scanf<i32> |
43.49 |
std::stringstream<i32> |
13.91 | std::stringstream<i32> |
12.03 |
write uint64_t |
MB/s | read uint64_t |
MB/s |
c4::to_chars<u64> |
1118.87 | c4::from_chars<u64> |
928.49 |
std::to_chars<u64> |
886.58 | std::from_chars<u64> |
759.03 |
std::sprintf<u64> |
140.96 | std::scanf<u64> |
91.60 |
std::stringstream<u64> |
28.01 | std::stringstream<u64> |
25.00 |
write int64_t |
MB/s | read int64_t |
MB/s |
c4::to_chars<i64> |
1198.78 | c4::from_chars<i64> |
713.76 |
std::to_chars<i64> |
882.17 | std::from_chars<i64> |
646.18 |
std::sprintf<i64> |
138.79 | std::scanf<i64> |
90.07 |
std::stringstream<i64> |
27.62 | std::stringstream<i64> |
25.12 |
Or here are plots for g++12.1 and VS2019 (from the same computer):
Linux gxx12.1 | Windows VS2019 |
---|---|
-
There is a useful quickstart sample in rapidyaml's doxygen docs.
// TODO: elaborate on the topics:
c4::cat(), c4::uncat()
c4::catsep(), c4::uncatsep()
c4::format(), c4::unformat()
c4::catrs()
c4::catseprs()
c4::formatrs()
// formatting:
c4::fmt::overflow_checked
c4::fmt::real
c4::fmt::boolalpha
c4::fmt::dec
c4::fmt::hex
c4::fmt::oct
c4::fmt::bin
c4::fmt::zpad
c4::fmt::right
c4::fmt::left
c4::fmt::raw, c4::fmt::craw
c4::fmt::base64, c4::fmt::cbase64
// TODO: elaborate on the topics:
c4::e2str(), c4::str2e()
// TODO: elaborate on the topics:
c4::bm2str(), c4::str2bm()
// TODO: elaborate on the topics:
#include <c4/error.hpp>
C4_RESTRICT, $, c$, $$, c$$
#include <c4/restrict.hpp>
#include <c4/unrestrict.hpp>
#include <c4/windows_push.hpp>
#include <c4/windows_pop.hpp>
C4_UNREACHABLE()
c4::type_name()
// portable attributes
C4_LIKELY()/C4_UNLIKELY()
C4_ALWAYS_INLINE
C4_CONST
C4_PURE
C4_HOT
C4_COLD
// TODO: elaborate on the topics:
error callback
C4_ASSERT()
C4_XASSERT()
C4_CHECK()
C4_ERROR()
C4_NOT_IMPLEMENTED()
// TODO: elaborate on the topics:
c4::aalloc(), c4::afree() // aligned allocation
c4::MemoryResource // global and scope
c4::Allocator
// TODO: elaborate on the topics:
c4::make_room()/c4::destroy_room()
c4::construct()/c4::construct_n()
c4::destroy()/c4::destroy_n()
c4::copy_construct()/c4::copy_construct_n()
c4::copy_assign()/c4::copy_assign_n()
c4::move_construct()/c4::move_construct_n()
c4::move_assign()/c4::move_assign_n()