mirror of
https://github.com/bolero-MURAKAMI/Sprout.git
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102 lines
3.3 KiB
C++
102 lines
3.3 KiB
C++
/*=============================================================================
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Copyright (c) 2011-2016 Bolero MURAKAMI
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https://github.com/bolero-MURAKAMI/Sprout
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Distributed under the Boost Software License, Version 1.0. (See accompanying
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file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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=============================================================================*/
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#ifndef SPROUT_MATH_IROUND_HPP
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#define SPROUT_MATH_IROUND_HPP
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#include <type_traits>
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#include <stdexcept>
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#include <sprout/config.hpp>
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#include <sprout/limits.hpp>
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#include <sprout/math/detail/config.hpp>
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#include <sprout/math/isnan.hpp>
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#include <sprout/math/isinf.hpp>
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#include <sprout/type_traits/enabler_if.hpp>
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#if SPROUT_USE_BUILTIN_CMATH_FUNCTION
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# include <sprout/math/round.hpp>
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#else
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# include <sprout/math/equal_to.hpp>
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#endif
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namespace sprout {
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namespace math {
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#if SPROUT_USE_BUILTIN_CMATH_FUNCTION
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namespace detail {
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template<typename To, typename FloatType>
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inline SPROUT_CONSTEXPR To
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iround_impl(FloatType x) {
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return sprout::numeric_limits<To>::max() < x || sprout::numeric_limits<To>::min() > x
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? SPROUT_MATH_THROW_LARGE_FLOAT_ROUNDING(std::runtime_error("iround: large float rounding."), static_cast<To>(x))
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: static_cast<To>(x)
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;
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}
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} // namespace detail
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//
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// iround
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//
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template<
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typename To = int,
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typename FloatType,
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typename sprout::enabler_if<std::is_floating_point<FloatType>::value && std::is_integral<To>::value>::type = sprout::enabler
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>
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inline SPROUT_CONSTEXPR To
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iround(FloatType x) {
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return sprout::math::isnan(x) || sprout::math::isinf(x) ? sprout::numeric_limits<To>::min()
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: sprout::math::detail::iround_impl<To>(sprout::math::round(x))
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;
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}
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#else
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namespace detail {
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template<typename To, typename FloatType>
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inline SPROUT_CONSTEXPR To
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iround_impl_positive(FloatType x, To x0) {
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return x - x0 < FloatType(0.5) ? x0
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: x0 + 1
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;
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}
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template<typename To, typename FloatType>
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inline SPROUT_CONSTEXPR To
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iround_impl_nagative(FloatType x, To x0) {
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return x0 - x < FloatType(0.5) ? x0
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: x0 - 1
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;
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}
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} // namespace detail
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//
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// iround
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//
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template<
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typename To = int,
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typename FloatType,
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typename sprout::enabler_if<std::is_floating_point<FloatType>::value && std::is_integral<To>::value>::type = sprout::enabler
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>
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inline SPROUT_CONSTEXPR To
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iround(FloatType x) {
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return sprout::math::isnan(x) || sprout::math::isinf(x) ? sprout::numeric_limits<To>::min()
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: x == 0 ? To(0)
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: sprout::numeric_limits<To>::max() < x || sprout::numeric_limits<To>::min() > x
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? SPROUT_MATH_THROW_LARGE_FLOAT_ROUNDING(std::runtime_error("iround: large float irounding."), x)
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: x < 0 ? sprout::math::detail::iround_impl_nagative(x, static_cast<To>(x))
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: sprout::math::detail::iround_impl_positive(x, static_cast<To>(x))
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;
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}
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#endif
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template<
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typename To = int,
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typename IntType,
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typename sprout::enabler_if<std::is_integral<IntType>::value && std::is_integral<To>::value>::type = sprout::enabler
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>
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inline SPROUT_CONSTEXPR To
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iround(IntType x) {
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return sprout::math::iround(static_cast<double>(x));
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}
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} // namespace math
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using sprout::math::iround;
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} // namespace sprout
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#endif // #ifndef SPROUT_MATH_IROUND_HPP
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