Sprout/sprout/math/acos.hpp
2013-04-25 15:36:19 +09:00

54 lines
1.5 KiB
C++

#ifndef SPROUT_MATH_ACOS_HPP
#define SPROUT_MATH_ACOS_HPP
#include <limits>
#include <type_traits>
#include <sprout/config.hpp>
#include <sprout/math/detail/config.hpp>
#include <sprout/math/detail/float_compute.hpp>
#include <sprout/math/asin.hpp>
#include <sprout/math/fabs.hpp>
#include <sprout/math/constants.hpp>
#include <sprout/type_traits/enabler_if.hpp>
namespace sprout {
namespace math {
namespace detail {
template<typename T>
inline SPROUT_CONSTEXPR T
acos_impl(T x) {
return sprout::math::half_pi<T>() - sprout::math::asin(x);
}
template<
typename FloatType,
typename sprout::enabler_if<std::is_floating_point<FloatType>::value>::type = sprout::enabler
>
inline SPROUT_CONSTEXPR FloatType
acos(FloatType x) {
return sprout::math::fabs(x) > 1 ? std::numeric_limits<FloatType>::quiet_NaN()
#if SPROUT_USE_BUILTIN_CMATH_FUNCTION
: std::acos(x)
#else
: x == 1 ? FloatType(0)
: static_cast<FloatType>(sprout::math::detail::acos_impl(static_cast<typename sprout::math::detail::float_compute<FloatType>::type>(x)))
#endif
;
}
template<
typename IntType,
typename sprout::enabler_if<std::is_integral<IntType>::value>::type = sprout::enabler
>
inline SPROUT_CONSTEXPR double
acos(IntType x) {
return sprout::math::detail::acos(static_cast<double>(x));
}
} // namespace detail
using sprout::math::detail::acos;
} // namespace math
using sprout::math::acos;
} // namespace sprout
#endif // #ifndef SPROUT_MATH_ACOS_HPP