Sprout/sprout/math/itrunc.hpp
2013-08-07 00:15:09 +09:00

72 lines
2.4 KiB
C++

#ifndef SPROUT_MATH_ITRUNC_HPP
#define SPROUT_MATH_ITRUNC_HPP
#include <type_traits>
#include <stdexcept>
#include <sprout/config.hpp>
#include <sprout/limits.hpp>
#include <sprout/math/detail/config.hpp>
#include <sprout/math/isnan.hpp>
#include <sprout/math/isinf.hpp>
#include <sprout/type_traits/enabler_if.hpp>
#if SPROUT_USE_BUILTIN_CMATH_FUNCTION
# include <sprout/math/trunc.hpp>
#endif
namespace sprout {
namespace math {
namespace detail {
#if SPROUT_USE_BUILTIN_CMATH_FUNCTION
template<typename To, typename FloatType>
inline SPROUT_CONSTEXPR To
itrunc_impl(FloatType x) {
return sprout::numeric_limits<To>::max() < x || sprout::numeric_limits<To>::min() > x
? SPROUT_MATH_THROW_LARGE_FLOAT_ROUNDING(std::runtime_error("itrunc: large float rounding."), static_cast<To>(x))
: static_cast<To>(x)
;
}
template<
typename To = int,
typename FloatType,
typename sprout::enabler_if<std::is_floating_point<FloatType>::value && std::is_integral<To>::value>::type = sprout::enabler
>
inline SPROUT_CONSTEXPR To
itrunc(FloatType x) {
return sprout::math::isnan(x) || sprout::math::isinf(x) ? sprout::numeric_limits<To>::min()
: sprout::math::detail::itrunc_impl<To>(sprout::math::trunc(x))
;
}
#else
template<
typename To = int,
typename FloatType,
typename sprout::enabler_if<std::is_floating_point<FloatType>::value && std::is_integral<To>::value>::type = sprout::enabler
>
inline SPROUT_CONSTEXPR To
itrunc(FloatType x) {
return sprout::math::isnan(x) || sprout::math::isinf(x) ? sprout::numeric_limits<To>::min()
: x == 0 ? To(0)
: sprout::numeric_limits<To>::max() < x || sprout::numeric_limits<To>::min() > x
? SPROUT_MATH_THROW_LARGE_FLOAT_ROUNDING(std::runtime_error("itrunc: large float rounding."), static_cast<To>(x))
: static_cast<To>(x)
;
}
#endif
template<
typename To = int,
typename IntType,
typename sprout::enabler_if<std::is_integral<IntType>::value && std::is_integral<To>::value>::type = sprout::enabler
>
inline SPROUT_CONSTEXPR To
itrunc(IntType x) {
return sprout::math::detail::itrunc<To>(static_cast<double>(x));
}
} // namespace detail
using sprout::math::detail::itrunc;
} // namespace math
using sprout::math::itrunc;
} // namespace sprout
#endif // #ifndef SPROUT_MATH_ITRUNC_HPP