Sprout/sprout/math/fractional_part.hpp
2013-05-06 00:22:08 +09:00

52 lines
1.6 KiB
C++

#ifndef SPROUT_MATH_FRACTIONAL_PART_HPP
#define SPROUT_MATH_FRACTIONAL_PART_HPP
#include <limits>
#include <type_traits>
#include <sprout/config.hpp>
#include <sprout/math/detail/config.hpp>
#include <sprout/math/copysign.hpp>
#include <sprout/math/isnan.hpp>
#include <sprout/math/integer_part.hpp>
#include <sprout/type_traits/enabler_if.hpp>
namespace sprout {
namespace math {
namespace detail {
template<typename T>
inline SPROUT_CONSTEXPR T
fractional_part_impl(T x, T ipart) {
return x == ipart ? T(0) * x
: sprout::math::copysign(x - ipart, x)
;
}
template<
typename FloatType,
typename sprout::enabler_if<std::is_floating_point<FloatType>::value>::type = sprout::enabler
>
inline SPROUT_CONSTEXPR FloatType
fractional_part(FloatType x) {
return sprout::math::isnan(x) ? x
: x == std::numeric_limits<FloatType>::infinity() || x == -std::numeric_limits<FloatType>::infinity() ? sprout::math::copysign(FloatType(0), x)
: x == 0 ? x
: sprout::math::detail::fractional_part_impl(x, sprout::integer_part(x))
;
}
template<
typename IntType,
typename sprout::enabler_if<std::is_integral<IntType>::value>::type = sprout::enabler
>
inline SPROUT_CONSTEXPR double
fractional_part(IntType x) {
return sprout::math::detail::fractional_part(static_cast<double>(x));
}
} // namespace detail
using sprout::math::detail::fractional_part;
} // namespace math
using sprout::math::fractional_part;
} // namespace sprout
#endif // #ifndef SPROUT_MATH_FRACTIONAL_PART_HPP