Added thirdparty: boost library

thirdparty/include/boost/math/ccmath/copysign.hpp

@@ -0,0 +1,81 @@
+//  (C) Copyright Matt Borland 2021.
+//  Use, modification and distribution are subject to 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 BOOST_MATH_CCMATH_COPYSIGN_HPP
+#define BOOST_MATH_CCMATH_COPYSIGN_HPP
+
+#include <cmath>
+#include <cstdint>
+#include <limits>
+#include <type_traits>
+#include <boost/math/tools/is_constant_evaluated.hpp>
+#include <boost/math/tools/promotion.hpp>
+#include <boost/math/tools/config.hpp>
+#include <boost/math/ccmath/abs.hpp>
+#include <boost/math/ccmath/signbit.hpp>
+
+namespace boost::math::ccmath {
+
+namespace detail {
+
+template <typename T>
+constexpr T copysign_impl(const T mag, const T sgn) noexcept
+{
+    if (boost::math::ccmath::signbit(sgn))
+    {
+        return -boost::math::ccmath::abs(mag);
+    }
+    else
+    {
+        return boost::math::ccmath::abs(mag);
+    }
+}
+
+} // Namespace detail
+
+template <typename Real, std::enable_if_t<!std::is_integral_v<Real>, bool> = true>
+constexpr Real copysign(Real mag, Real sgn) noexcept
+{
+    if(BOOST_MATH_IS_CONSTANT_EVALUATED(mag))
+    {
+        return boost::math::ccmath::detail::copysign_impl(mag, sgn);
+    }
+    else
+    {
+        using std::copysign;
+        return copysign(mag, sgn);
+    }
+}
+
+template <typename T1, typename T2>
+constexpr auto copysign(T1 mag, T2 sgn) noexcept
+{
+    if (BOOST_MATH_IS_CONSTANT_EVALUATED(mag))
+    {        
+        using promoted_type = boost::math::tools::promote_args_2_t<T1, T2>;
+        return boost::math::ccmath::copysign(static_cast<promoted_type>(mag), static_cast<promoted_type>(sgn));
+    }
+    else
+    {
+        using std::copysign;
+        return copysign(mag, sgn);
+    }
+}
+
+constexpr float copysignf(float mag, float sgn) noexcept
+{
+    return boost::math::ccmath::copysign(mag, sgn);
+}
+
+#ifndef BOOST_MATH_NO_LONG_DOUBLE_MATH_FUNCTIONS
+constexpr long double copysignl(long double mag, long double sgn) noexcept
+{
+    return boost::math::ccmath::copysign(mag, sgn);
+}
+#endif
+
+} // Namespaces
+
+#endif // BOOST_MATH_CCMATH_COPYSIGN_HPP