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#pragma once
#include <bit>
#include <cmath>
namespace floormat::math::detail {
constexpr double sqrt_newton_raphson(double x, double curr, double prev)
{
return curr == prev
? curr
: sqrt_newton_raphson(x, 0.5 * (curr + x / curr), curr);
}
template<typename T> requires std::is_floating_point_v<T> struct float_constants;
template<>
struct float_constants<double>
{
static constexpr auto quiet_nan = std::bit_cast<double>(uint64_t(0x7FF8000000000000ULL));
static constexpr auto positive_infinity = std::bit_cast<double>(uint64_t(0x7FF0000000000000ULL));
static constexpr auto negative_infinity = std::bit_cast<double>(uint64_t(0xFFF0000000000000ULL));
};
template<>
struct float_constants<float>
{
static constexpr auto quiet_nan = std::bit_cast<float>(uint32_t(0x7FC00000U));
static constexpr auto positive_infinity = std::bit_cast<float>(uint32_t(0x7F800000U));
static constexpr auto negative_infinity = std::bit_cast<float>(uint32_t(0xFF800000U));
};
} // namespace floormat::math::detail
namespace floormat::math {
template<typename T>
constexpr inline T sqrt(T x)
requires std::is_floating_point_v<T>
{
if (std::is_constant_evaluated())
{
using K = detail::float_constants<T>;
return x >= 0 && x < K::positive_infinity
? T(detail::sqrt_newton_raphson(double(x), double(x), 0))
: K::quiet_nan;
}
else
return std::sqrt(x);
}
template<typename T>
requires std::is_integral_v<T>
constexpr inline double sqrt(T x)
{
return sqrt(double(x));
}
template<typename T>
requires std::is_floating_point_v<T>
constexpr inline T ceil(T x)
{
if (std::is_constant_evaluated())
{
#ifdef __GNUG__
return __builtin_ceil(x);
#else
const auto x0 = uint64_t(x);
if (x > x0)
return T(x0 + uint64_t(1));
else
return x0;
#endif
}
else
return std::ceil(x);
}
} // namespace floormat::math
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