Sprout/sprout/math/signbit.hpp
2013-04-26 00:25:35 +09:00

35 lines
943 B
C++

#ifndef SPROUT_MATH_SIGNBIT_HPP
#define SPROUT_MATH_SIGNBIT_HPP
#include <type_traits>
#include <sprout/config.hpp>
#include <sprout/math/detail/config.hpp>
#include <sprout/math/isnan.hpp>
#include <sprout/type_traits/enabler_if.hpp>
namespace sprout {
namespace math {
namespace detail {
template<
typename FloatType,
typename sprout::enabler_if<std::is_floating_point<FloatType>::value>::type = sprout::enabler
>
inline SPROUT_CONSTEXPR bool
signbit(FloatType x) {
return !sprout::math::isnan(x) && x < 0;
}
} // namespace detail
//
// bug:
// signbit(-0) returns false .
// # returns true . ( same as signbit(+0) )
// signbit(-NaN) returns false .
// # returns true . ( same as signbit(+NaN) )
//
using NS_SPROUT_MATH_DETAIL::signbit;
} // namespace math
using sprout::math::signbit;
} // namespace sprout
#endif // #ifndef SPROUT_MATH_SIGNBIT_HPP