bit14

This is a recreation of the C++20 bit header written in C++14.

https://en.cppreference.com/w/cpp/header/bit

This project is intended for anyone who wishes to use the standard library header bit.h but is stuck on c++14 or 17. Simply add folder bit14 to your list of include directories and #include bit14.h where desired. On msvc, gcc, clang, IBM XL / Open XL for Linux or AIX, or Intel ICC / ICPX compilers it uses x86, ARM or Power intrinsics whenever available. Otherwise, it falls back on a generic solution. On other compilers, a fully generic solution is used. All function descriptions on cppreference.com apply exactly to the functions in this header with the following exceptions:

• All functions and enums in this header exist within namespace bit14.
• Extended integer types are not supported.
• The target platform must use the ILP32, LLP64 or LP64 data model, meaning char = 1 byte, short = 2 bytes, int = 4 bytes, long = 4 or 8 bytes and long long = 8 bytes.
• Every function in this header other than bit14::bit_cast has a seperate constexpr version that takes its arguments as template parameters (see below). bit14::bit_cast has no constexpr version.
• The endian enum only exists on gcc, clang, msvc, IBM XL / Open XL for Linux or AIX and Intel ICC / ICPX compilers.
• If using C++14, bit14::byteswap does not check for padding bits.
• bit14::bitceil is noexcept

constexpr functions

The interface for all constexpr functions are listed below:

template <typename T, T Value>
constexpr int bit14::popcount() noexcept;

template <typename T, T Value>
constexpr int bit14::countr_zero() noexcept;

template <typename T, T Value>
constexpr int bit14::countl_zero() noexcept;

template <typename T, T Value>
constexpr int bit14::countr_one() noexcept;

template <typename T, T Value>
constexpr int bit14::countl_one() noexcept;

template <typename T, T Value, int Shift>
constexpr T bit14::rotl() noexcept;

template <typename T, T Value, int Shift>
constexpr T bit14::rotr() noexcept;

template <typename T, T Value>
constexpr int bit14::bit_width() noexcept;

template <typename T, T Value>
constexpr T bit14::bit_floor() noexcept;

template <typename T, T Value>
constexpr T bit14::bit_ceil() noexcept;

template <typename T, T Value>
constexpr bool bit14::has_single_bit() noexcept;

template<typename T, T Value>
constexpr T bit14::byteswap() noexcept;