mirror of
https://github.com/bolero-MURAKAMI/Sprout.git
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93 lines
3.2 KiB
C++
93 lines
3.2 KiB
C++
/*=============================================================================
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Copyright (c) 2011-2014 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_COPYSIGN_HPP
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#define SPROUT_MATH_COPYSIGN_HPP
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#include <type_traits>
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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/type_traits/float_promote.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 || SPROUT_USE_BUILTIN_COPYSIGN_FUNCTION
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inline SPROUT_CONSTEXPR float
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builtin_copysign(float x, float y) {
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return __builtin_copysignf(x, y);
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}
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inline SPROUT_CONSTEXPR double
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builtin_copysign(double x, double y) {
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return __builtin_copysign(x, y);
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}
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inline SPROUT_CONSTEXPR long double
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builtin_copysign(long double x, long double y) {
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return __builtin_copysignl(x, y);
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}
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#endif
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template<typename FloatType>
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inline SPROUT_CONSTEXPR bool
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broken_signbit(FloatType x) {
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return !sprout::math::isnan(x) && x < 0;
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}
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} // namespace detail
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//
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// copysign
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//
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// issue:
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// [ !(SPROUT_USE_BUILTIN_CMATH_FUNCTION || SPROUT_USE_BUILTIN_COPYSIGN_FUNCTION) ]
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// copysign(<28>}x, -0) returns -x for |x| is not 0 .
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// # returns +x . ( same as copysign(<28>}x, +0) )
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// copysign(<28>}x, -NaN) returns -x for |x| is not NaN .
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// # returns +x . ( same as copysign(<28>}x, +NaN) )
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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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copysign(FloatType x, FloatType y) {
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return
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#if SPROUT_USE_BUILTIN_CMATH_FUNCTION || SPROUT_USE_BUILTIN_COPYSIGN_FUNCTION
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sprout::math::detail::builtin_copysign(x, y)
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#else
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x == 0
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? y == 0 ? y
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: sprout::math::detail::broken_signbit(y) ? -FloatType(0)
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: FloatType(0)
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: sprout::math::isnan(x)
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? sprout::math::isnan(y) ? y
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: sprout::math::detail::broken_signbit(y) ? -sprout::numeric_limits<FloatType>::quiet_NaN()
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: sprout::numeric_limits<FloatType>::quiet_NaN()
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: sprout::math::detail::broken_signbit(y) != sprout::math::detail::broken_signbit(x) ? -x
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: x
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#endif
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;
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}
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template<
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typename ArithmeticType1,
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typename ArithmeticType2,
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typename sprout::enabler_if<
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std::is_arithmetic<ArithmeticType1>::value && std::is_arithmetic<ArithmeticType2>::value
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>::type = sprout::enabler
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>
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inline SPROUT_CONSTEXPR typename sprout::float_promote<ArithmeticType1, ArithmeticType2>::type
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copysign(ArithmeticType1 x, ArithmeticType2 y) {
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typedef typename sprout::float_promote<ArithmeticType1, ArithmeticType2>::type type;
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return sprout::math::copysign(static_cast<type>(x), static_cast<type>(y));
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}
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} // namespace math
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using sprout::math::copysign;
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} // namespace sprout
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#endif // #ifndef SPROUT_MATH_COPYSIGN_HPP
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