Sprout/sprout/math/ifloor.hpp
2019-01-07 17:47:17 +09:00

94 lines
3.1 KiB
C++

/*=============================================================================
Copyright (c) 2011-2019 Bolero MURAKAMI
https://github.com/bolero-MURAKAMI/Sprout
Distributed under the Boost Software License, Version 1.0. (See accompanying
file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
=============================================================================*/
#ifndef SPROUT_MATH_IFLOOR_HPP
#define SPROUT_MATH_IFLOOR_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/floor.hpp>
#else
# include <sprout/math/greater_equal.hpp>
#endif
namespace sprout {
namespace math {
#if SPROUT_USE_BUILTIN_CMATH_FUNCTION
namespace detail {
template<typename To, typename FloatType>
inline SPROUT_CONSTEXPR To
ifloor_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("ifloor: large float rounding."), static_cast<To>(x))
: static_cast<To>(x)
;
}
} // namespace detail
//
// ifloor
//
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::isnan(x) || sprout::math::isinf(x) ? sprout::numeric_limits<To>::min()
: sprout::math::detail::ifloor_impl<To>(sprout::math::floor(x))
;
}
#else
namespace detail {
template<typename To, typename FloatType>
inline SPROUT_CONSTEXPR To
ifloor_impl(FloatType x, To x0) {
return sprout::math::greater_equal(x, x0) ? x0
: x0 - 1
;
}
} // namespace detail
//
// ifloor
//
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::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("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::ifloor<To>(static_cast<double>(x));
}
} // namespace math
using sprout::math::ifloor;
} // namespace sprout
#endif // #ifndef SPROUT_MATH_IFLOOR_HPP