int_math.hpp File Reference

#include <cstdint>
#include <cmath>
#include <climits>
#include <jau/base_math.hpp>
#include <jau/int_math_ct.hpp>

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Namespaces
namespace	jau
	__pack(...): Produces MSVC, clang and gcc compatible lead-in and -out macros.

Functions
template<typename T, std::enable_if_t< std::is_integral_v< T >, bool > = true>
constexpr bool	jau::add_overflow (const T a, const T b, T &res) noexcept
	Integer overflow aware addition returning true if overflow occurred, otherwise false having the result stored in res.
template<typename T, std::enable_if_t< std::is_integral_v< T >, bool > = true>
constexpr nsize_t	jau::digits10 (const T x, const bool sign_is_digit=true) noexcept
	Returns the number of decimal digits of the given integral value number using std::log10<T>().
template<typename T, std::enable_if_t< std::is_integral_v< T >, bool > = true>
constexpr nsize_t	jau::digits10 (const T x, const snsize_t x_sign, const bool sign_is_digit=true) noexcept
	Returns the number of decimal digits of the given integral value number using std::log10<T>().
template<class T>
std::enable_if_t< std::is_integral_v< T >, bool > constexpr	jau::equals (const T &a, const T &b) noexcept
	Returns true if both values are equal.
template<class T>
std::enable_if_t< std::is_integral_v< T >, bool > constexpr	jau::equals (const T &a, const T &b, const T &allowed_deviation) noexcept
	Returns true if both values are equal, i.e.
template<typename T, std::enable_if_t< std::is_integral_v< T > &&!std::is_unsigned_v< T >, bool > = true>
constexpr T	jau::gcd (T a, T b) noexcept
	Returns the greatest common divisor (GCD) of the two given integer values following Euclid's algorithm from Euclid's Elements ~300 BC, using the absolute positive value of given integers.
consteval_cxx20 bool	jau::has_builtin_add_overflow () noexcept
	Query whether __builtin_add_overflow is available via __has_builtin(__builtin_add_overflow).
consteval_cxx20 bool	jau::has_builtin_mul_overflow () noexcept
	Query whether __builtin_mul_overflow is available via __has_builtin(__builtin_mul_overflow).
consteval_cxx20 bool	jau::has_builtin_sub_overflow () noexcept
	Query whether __builtin_sub_overflow is available via __has_builtin(__builtin_sub_overflow).
template<typename T, std::enable_if_t< std::is_integral_v< T > &&std::is_unsigned_v< T >, bool > = true>
constexpr nsize_t	jau::high_bit (T x)
	Return the index of the highest set bit w/ branching (loop) in O(n), actually O(n/2).
template<typename T, std::enable_if_t< std::is_integral_v< T > &&std::is_unsigned_v< T >, bool > = true>
constexpr bool	jau::is_power_of_2 (const T x) noexcept
	Power of 2 test (w/o branching ?) in O(1)
template<class T>
std::enable_if_t< std::is_integral_v< T >, bool > constexpr	jau::is_zero (const T &a) noexcept
	base_math: arithmetic types, i.e.
template<typename T, std::enable_if_t< std::is_integral_v< T >, bool > = true>
constexpr bool	jau::lcm_overflow (const T a, const T b, T &result) noexcept
	Integer overflow aware calculation of least common multiple (LCM) following Euclid's algorithm from Euclid's Elements ~300 BC.
template<typename T, std::enable_if_t< std::is_integral_v< T >, bool > = true>
constexpr bool	jau::mul_overflow (const T a, const T b, T &res) noexcept
	Integer overflow aware multiplication returning true if overflow occurred, otherwise false having the result stored in res.
template<typename T, typename U, std::enable_if_t< std::is_integral_v< T > &&std::is_unsigned_v< T > &&std::is_integral_v< U > &&std::is_unsigned_v< U >, bool > = true>
constexpr T	jau::round_down (T n, U align_to)
	Round down w/ branching in O(1)
constexpr uint32_t	jau::round_to_power_of_2 (const uint32_t n)
	If the given n is not is_power_of_2() return next_power_of_2(), otherwise return n unchanged.
template<typename T, typename U, std::enable_if_t< std::is_integral_v< T > &&std::is_unsigned_v< T > &&std::is_integral_v< U > &&std::is_unsigned_v< U >, bool > = true>
constexpr T	jau::round_up (const T n, const U align_to)
	Round up w/ branching in O(1)
template<typename T, std::enable_if_t< std::is_integral_v< T >, bool > = true>
constexpr bool	jau::sub_overflow (const T a, const T b, T &res) noexcept
	Integer overflow aware subtraction returning true if overflow occurred, otherwise false having the result stored in res.