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Sprout/sprout/math/ifloor.hpp
2013-03-18 19:12:21 +09:00

76 lines
2.4 KiB
C++

#ifndef SPROUT_MATH_IFLOOR_HPP
#define SPROUT_MATH_IFLOOR_HPP
#include <limits>
#include <type_traits>
#include <stdexcept>
#include <sprout/config.hpp>
#include <sprout/math/detail/config.hpp>
#include <sprout/type_traits/enabler_if.hpp>
#if SPROUT_USE_BUILTIN_CMATH_FUNCTION
# include <sprout/math/floor.hpp>
#else
# include <sprout/math/equal_to.hpp>
#endif
namespace sprout {
namespace math {
namespace detail {
#if SPROUT_USE_BUILTIN_CMATH_FUNCTION
template<typename To, typename FloatType>
inline SPROUT_CONSTEXPR To
ifloor_impl(FloatType x) {
return std::numeric_limits<To>::max() < x || std::numeric_limits<To>::min() > x
? SPROUT_MATH_THROW_LARGE_FLOAT_ROUNDING(std::runtime_error("ifloor: 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
ifloor(FloatType x) {
return sprout::math::detail::ifloor_impl<To>(sprout::math::floor(x));
}
#else
template<typename To, typename FloatType>
inline SPROUT_CONSTEXPR To
ifloor_impl(FloatType x, To x0) {
return sprout::math::equal_to(x, x0) ? x0
: x0 - 1
;
}
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
ifloor(FloatType x) {
return x == 0 ? To(0)
: std::numeric_limits<To>::max() < x || std::numeric_limits<To>::min() > x
? SPROUT_MATH_THROW_LARGE_FLOAT_ROUNDING(std::runtime_error("ifloor: large float rounding."), static_cast<To>(x))
: sprout::math::detail::ifloor_impl(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
ifloor(IntType x) {
return sprout::math::detail::ifloor<To>(static_cast<double>(x));
}
} // namespace detail
using sprout::math::detail::ifloor;
} // namespace math
using sprout::math::ifloor;
} // namespace sprout
#endif // #ifndef SPROUT_MATH_IFLOOR_HPP