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Sprout/sprout/math/atan2.hpp
2012-05-04 23:47:54 +09:00

91 lines
2.6 KiB
C++

#ifndef SPROUT_MATH_ATAN2_HPP
#define SPROUT_MATH_ATAN2_HPP
#include <type_traits>
#include <sprout/config.hpp>
#include <sprout/math/atan.hpp>
#include <sprout/math/constants.hpp>
#include <sprout/utility/enabler_if.hpp>
#if SPROUT_USE_BUILTIN_CMATH_FUNCTION
# include <cmath>
#endif
namespace sprout {
namespace math {
namespace detail {
template<typename Y, typename X, typename Enable = void>
struct atan2_promoted {};
template<typename Y, typename X>
struct atan2_promoted<
Y,
X,
typename std::enable_if<
std::is_arithmetic<Y>::value && std::is_arithmetic<X>::value
&& (std::is_same<Y, long double>::value || std::is_same<X, long double>::value)
>::type
> {
public:
typedef long double type;
};
template<typename Y, typename X>
struct atan2_promoted<
Y,
X,
typename std::enable_if<
std::is_arithmetic<Y>::value && std::is_arithmetic<X>::value
&& !(std::is_same<Y, long double>::value || std::is_same<X, long double>::value)
>::type
> {
public:
typedef double type;
};
} // namespace detail
//
// atan2_promoted
//
template<typename Y, typename X>
struct atan2_promoted
: public sprout::math::detail::atan2_promoted<
typename std::remove_cv<Y>::type,
typename std::remove_cv<X>::type
>
{};
namespace detail {
template<
typename FloatType,
typename sprout::enabler_if<std::is_floating_point<FloatType>::value>::type = sprout::enabler
>
inline SPROUT_CONSTEXPR FloatType
atan2(FloatType y, FloatType x) {
return x < 0
? sprout::math::detail::atan(y / x) + (y < 0 ? -1 : 1) * sprout::math::pi<FloatType>()
: sprout::math::detail::atan(y / x)
;
}
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::math::atan2_promoted<ArithmeticType1, ArithmeticType2>::type
atan2(ArithmeticType1 y, ArithmeticType2 x) {
typedef typename sprout::math::atan2_promoted<ArithmeticType1, ArithmeticType2>::type type;
return sprout::math::detail::atan2(static_cast<type>(y), static_cast<type>(x));
}
} // namespace detail
# if SPROUT_USE_BUILTIN_CMATH_FUNCTION
using std::atan2;
# else
using sprout::math::detail::atan2;
# endif
} // namespace math
using sprout::math::atan2;
} // namespace sprout
#endif // #ifndef SPROUT_MATH_ATAN2_HPP