Sprout/sprout/math/fractional_part.hpp
2016-02-25 18:48:28 +09:00

59 lines
2 KiB
C++

/*=============================================================================
Copyright (c) 2011-2016 Bolero MURAKAMI
https://github.com/bolero-MURAKAMI/Sprout
Distributed under the Boost Software License, Version 1.0. (See accompanying
file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
=============================================================================*/
#ifndef SPROUT_MATH_FRACTIONAL_PART_HPP
#define SPROUT_MATH_FRACTIONAL_PART_HPP
#include <type_traits>
#include <sprout/config.hpp>
#include <sprout/limits.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)
;
}
} // namespace detail
//
// fractional_part
//
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 == sprout::numeric_limits<FloatType>::infinity() || x == -sprout::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::fractional_part(static_cast<double>(x));
}
} // namespace math
using sprout::math::fractional_part;
} // namespace sprout
#endif // #ifndef SPROUT_MATH_FRACTIONAL_PART_HPP