text: /*=============================================================================
    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_FLOOR_HPP
  #define SPROUT_MATH_FLOOR_HPP
  
  #include <cstdint>
  #include <type_traits>
  #include <stdexcept>
  #include <sprout/config.hpp>
  #include <sprout/limits.hpp>
  #include <sprout/math/detail/config.hpp>
  #include <sprout/math/detail/float_compute.hpp>
  #include <sprout/math/isnan.hpp>
  #include <sprout/math/equal_to.hpp>
  #include <sprout/type_traits/enabler_if.hpp>
  
  namespace sprout {
  	namespace math {
  		namespace detail {
  #if SPROUT_USE_BUILTIN_CMATH_FUNCTION
  			inline SPROUT_CONSTEXPR float
  			builtin_floor(float x) {
  				return __builtin_floorf(x);
  			}
  			inline SPROUT_CONSTEXPR double
  			builtin_floor(double x) {
  				return __builtin_floor(x);
  			}
  			inline SPROUT_CONSTEXPR long double
  			builtin_floor(long double x) {
  				return __builtin_floorl(x);
  			}
  #endif
  
  			template<typename T>
  			inline SPROUT_CONSTEXPR T
  			floor_impl_1(T x, T x0) {
  				return sprout::math::equal_to(x, x0) ? x0
  					: x0 - T(1)
  					;
  			}
  			template<typename T>
  			inline SPROUT_CONSTEXPR T
  			floor_impl(T x) {
  				return x < 0 ? sprout::math::detail::floor_impl_1(x, -static_cast<T>(static_cast<std::uintmax_t>(-x)))
  					: static_cast<T>(static_cast<std::uintmax_t>(x))
  					;
  			}
  		}	// namespace detail
  		//
  		// floor
  		//
  		template<
              typename T,
              typename sprout::enabler_if<std::is_floating_point<T>::value>::type = sprout::enabler
          >
          inline SPROUT_CONSTEXPR T
          floor(T x) {
              return sprout::math::isnan(x) ? x
                  : x ==  sprout::numeric_limits<T>::infinity() ?  sprout::numeric_limits<T>::infinity()
                  : x == -sprout::numeric_limits<T>::infinity() ? -sprout::numeric_limits<T>::infinity()
  #if SPROUT_USE_BUILTIN_CMATH_FUNCTION
  				: sprout::math::detail::builtin_floor(x)
  #else
                  : x == 0 ? x
                  : x > 0
                  ? ( x < static_cast< T >(sprout::numeric_limits< std::uintmax_t >::max())
                     ? static_cast<T>(
                         sprout::math::detail::floor_impl(
                             static_cast< typename sprout::math::detail::float_compute< T >::type >(x)))
                     : SPROUT_MATH_THROW_LARGE_FLOAT_ROUNDING(std::runtime_error("floor: large float rounding."), x))
                  : (-x < static_cast<T>(sprout::numeric_limits< std::uintmax_t >::max())
                     ? static_cast<T>(
                         sprout::math::detail::floor_impl(
                             static_cast< typename sprout::math::detail::float_compute< T >::type >(x)))
                     : SPROUT_MATH_THROW_LARGE_FLOAT_ROUNDING(std::runtime_error("floor: large float rounding."), x))
  #endif
  				;
  		}
  		template<
  			typename IntType,
  			typename sprout::enabler_if<std::is_integral<IntType>::value>::type = sprout::enabler
  		>
  		inline SPROUT_CONSTEXPR double
  		floor(IntType x) {
  			return sprout::math::floor(static_cast<double>(x));
  		}
  	}	// namespace math
  
  	using sprout::math::floor;
  }	// namespace sprout
  
  #endif	// #ifndef SPROUT_MATH_FLOOR_HPP
  