c4core - C++ core utilities

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 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.

Obtaining c4core

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.

Using c4core in your project

c4core is built with cmake, and assumes you also use cmake. Although c4core is NOT header-only, and currently has no install target, you can very easily use c4core in your project by using add_subdirectory(${path_to_c4core_root}) in your CMakeLists.txt; this will add c4core as a subproject of your project. Doing this is not intrusive to your cmake project because c4core is fast to build (typically under 10s), and it 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:

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.

Quick tour

All of the utilities in this library are under the namespace c4; any exposed macros use the prefix C4_: eg C4_ASSERT().

Writeable string views: c4::substr and c4::csubstr

Here: #include <c4/substr.hpp>

Value <-> character interoperation

Here: #include <c4/charconv.hpp>

// TODO: elaborate on the topics:

c4::read_dec(), c4::write_dec()
c4::read_hex(), c4::write_hex()
c4::read_oct(), c4::write_oct()
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 by stringstream::str()
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 by stringstream::operator>>()

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

String formatting and parsing

#include <c4/format.hpp>

// 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

`c4::span` and `c4::blob`

Enums and enum symbols

#include <c4/enum.hpp>

// TODO: elaborate on the topics:

c4::e2str(), c4::str2e()

Bitmasks and bitmask symbols

#include <c4/bitmask.hpp>

// TODO: elaborate on the topics:

c4::bm2str(), c4::str2bm()

Base64 encoding / decoding

#include <c4/base64.hpp>

Fuzzy float comparison

Multi-platform / multi-compiler utilities

// TODO: elaborate on the topics:
#include <c4/error.hpp>

C4_LIKELY()/C4_UNLIKELY()

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()

Runtime assertions and error handling

// TODO: elaborate on the topics:

error callback

C4_ASSERT()
C4_XASSERT()
C4_CHECK()

C4_ERROR()
C4_NOT_IMPLEMENTED()

Memory allocation

// TODO: elaborate on the topics:

c4::aalloc(), c4::afree() // aligned allocation

c4::MemoryResource // global and scope

c4::Allocator

Mass initialization/construction/destruction

// TODO: elaborate on the topics:

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()

c4::make_room()/c4::destroy_room()

daichifukui/c4core