mirror of
https://github.com/bolero-MURAKAMI/Sprout.git
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96 lines
3.1 KiB
C++
96 lines
3.1 KiB
C++
/*=============================================================================
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Copyright (c) 2011-2013 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_ROUND_HPP
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#define SPROUT_MATH_ROUND_HPP
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#include <cstdint>
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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/detail/float_compute.hpp>
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#include <sprout/math/isnan.hpp>
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#include <sprout/type_traits/enabler_if.hpp>
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namespace sprout {
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namespace math {
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namespace detail {
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#if SPROUT_USE_BUILTIN_CMATH_FUNCTION
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inline SPROUT_CONSTEXPR float
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builtin_round(float x) {
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return __builtin_roundf(x);
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}
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inline SPROUT_CONSTEXPR double
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builtin_round(double x) {
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return __builtin_round(x);
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}
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inline SPROUT_CONSTEXPR long double
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builtin_round(long double x) {
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return __builtin_roundl(x);
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}
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#endif
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template<typename T>
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inline SPROUT_CONSTEXPR T
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round_impl_positive(T x, T x0) {
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return x - x0 < T(0.5) ? x0
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: x0 + T(1)
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;
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}
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template<typename T>
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inline SPROUT_CONSTEXPR T
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round_impl_nagative(T x, T x0) {
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return x0 - x < T(0.5) ? x0
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: x0 - T(1)
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;
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}
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template<typename T>
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inline SPROUT_CONSTEXPR T
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round_impl(T x) {
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return x < 0 ? sprout::math::detail::round_impl_nagative(x, -static_cast<T>(static_cast<std::uintmax_t>(-x)))
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: sprout::math::detail::round_impl_positive(x, static_cast<T>(static_cast<std::uintmax_t>(x)))
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;
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}
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} // namespace detail
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//
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// round
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//
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template<
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typename FloatType,
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typename sprout::enabler_if<std::is_floating_point<FloatType>::value>::type = sprout::enabler
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>
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inline SPROUT_CONSTEXPR FloatType
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round(FloatType x) {
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return sprout::math::isnan(x) ? x
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: x == sprout::numeric_limits<FloatType>::infinity() ? sprout::numeric_limits<FloatType>::infinity()
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: x == -sprout::numeric_limits<FloatType>::infinity() ? -sprout::numeric_limits<FloatType>::infinity()
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#if SPROUT_USE_BUILTIN_CMATH_FUNCTION
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: sprout::math::detail::builtin_round(x)
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#else
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: x == 0 ? x
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: sprout::numeric_limits<std::uintmax_t>::max() < x || sprout::numeric_limits<std::uintmax_t>::max() < -x
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? SPROUT_MATH_THROW_LARGE_FLOAT_ROUNDING(std::runtime_error("round: large float rounding."), x)
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: static_cast<FloatType>(sprout::math::detail::round_impl(static_cast<typename sprout::math::detail::float_compute<FloatType>::type>(x)))
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#endif
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;
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}
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template<
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typename IntType,
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typename sprout::enabler_if<std::is_integral<IntType>::value>::type = sprout::enabler
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>
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inline SPROUT_CONSTEXPR double
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round(IntType x) {
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return sprout::math::round(static_cast<double>(x));
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}
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} // namespace math
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using sprout::math::round;
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} // namespace sprout
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#endif // #ifndef SPROUT_MATH_ROUND_HPP
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