Sprout/sprout/math/hypot.hpp
2014-01-08 16:48:12 +09:00

105 lines
3.6 KiB
C++

/*=============================================================================
Copyright (c) 2011-2014 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_HYPOT_HPP
#define SPROUT_MATH_HYPOT_HPP
#include <type_traits>
#include <sprout/config.hpp>
#include <sprout/limits.hpp>
#include <sprout/math/detail/config.hpp>
#include <sprout/math/detail/float_compute.hpp>
#include <sprout/math/isnan.hpp>
#include <sprout/math/signbit.hpp>
#include <sprout/math/fabs.hpp>
#include <sprout/math/sqrt.hpp>
#include <sprout/type_traits/float_promote.hpp>
#include <sprout/type_traits/enabler_if.hpp>
namespace sprout {
namespace math {
namespace detail {
#if SPROUT_USE_BUILTIN_CMATH_FUNCTION
inline SPROUT_CONSTEXPR float
builtin_hypot(float x, float y) {
return __builtin_hypotf(x, y);
}
inline SPROUT_CONSTEXPR double
builtin_hypot(double x, double y) {
return __builtin_hypot(x, y);
}
inline SPROUT_CONSTEXPR long double
builtin_hypot(long double x, long double y) {
return __builtin_hypotl(x, y);
}
#endif
template<typename T>
inline SPROUT_CONSTEXPR T
hypot_impl_2(T t, T w) {
return t * sprout::math::sqrt(T(1) + w * w);
}
template<typename T>
inline SPROUT_CONSTEXPR T
hypot_impl_1(T x, T y) {
return x < y
? sprout::math::detail::hypot_impl_2(y, x / y)
: sprout::math::detail::hypot_impl_2(x, y / x)
;
}
template<typename T>
inline SPROUT_CONSTEXPR T
hypot_impl(T x, T y) {
return sprout::math::detail::hypot_impl_1(sprout::math::fabs(x), sprout::math::fabs(y));
}
} // namespace detail
//
// hypot
//
template<
typename FloatType,
typename sprout::enabler_if<std::is_floating_point<FloatType>::value>::type = sprout::enabler
>
inline SPROUT_CONSTEXPR FloatType
hypot(FloatType x, FloatType y) {
return y == sprout::numeric_limits<FloatType>::infinity() || y == -sprout::numeric_limits<FloatType>::infinity()
? sprout::numeric_limits<FloatType>::infinity()
: x == sprout::numeric_limits<FloatType>::infinity() || x == -sprout::numeric_limits<FloatType>::infinity()
? sprout::numeric_limits<FloatType>::infinity()
: sprout::math::isnan(y) ? y
: sprout::math::isnan(x) ? x
#if SPROUT_USE_BUILTIN_CMATH_FUNCTION
: sprout::math::detail::builtin_hypot(x, y)
#else
: y == 0 ? sprout::math::fabs(x)
: x == 0 ? sprout::math::fabs(y)
: static_cast<FloatType>(sprout::math::detail::hypot_impl(
static_cast<typename sprout::math::detail::float_compute<FloatType>::type>(x),
static_cast<typename sprout::math::detail::float_compute<FloatType>::type>(y)
))
#endif
;
}
template<
typename ArithmeticType1,
typename ArithmeticType2,
typename sprout::enabler_if<
std::is_arithmetic<ArithmeticType1>::value && std::is_arithmetic<ArithmeticType2>::value
>::type = sprout::enabler
>
inline SPROUT_CONSTEXPR typename sprout::float_promote<ArithmeticType1, ArithmeticType2>::type
hypot(ArithmeticType1 x, ArithmeticType2 y) {
typedef typename sprout::float_promote<ArithmeticType1, ArithmeticType2>::type type;
return sprout::math::hypot(static_cast<type>(x), static_cast<type>(y));
}
} // namespace math
using sprout::math::hypot;
} // namespace sprout
#endif // #ifndef SPROUT_MATH_HYPOT_HPP