Sprout/sprout/math/log2.hpp
2012-05-04 18:02:42 +09:00

45 lines
1.1 KiB
C++

#ifndef SPROUT_MATH_LOG2HPP
#define SPROUT_MATH_LOG2HPP
#include <type_traits>
#include <sprout/config.hpp>
#include <sprout/math/log.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 FloatType,
typename sprout::enabler_if<std::is_floating_point<FloatType>::value>::type = sprout::enabler
>
inline SPROUT_CONSTEXPR FloatType
log2(FloatType x) {
return sprout::math::detail::log(x) / sprout::math::ln_two<FloatType>();
}
template<
typename IntType,
typename sprout::enabler_if<std::is_integral<IntType>::value>::type = sprout::enabler
>
inline SPROUT_CONSTEXPR double
log2(IntType x) {
return sprout::math::detail::log2(static_cast<double>(x));
}
} // namespace detail
# if SPROUT_USE_BUILTIN_CMATH_FUNCTION
using std::log2;
# else
using sprout::math::detail::log2;
# endif
} // namespace math
using sprout::math::log2;
} // namespace sprout
#endif // #ifndef SPROUT_MATH_LOG2HPP