Added thirdparty: boost library

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

@@ -0,0 +1,89 @@
+//  (C) Copyright Matt Borland 2022.
+//  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_FMAX_HPP
+#define BOOST_MATH_CCMATH_FMAX_HPP
+
+#include <boost/math/ccmath/detail/config.hpp>
+
+#ifdef BOOST_MATH_NO_CCMATH
+#error "The header <boost/math/fmax.hpp> can only be used in C++17 and later."
+#endif
+
+#include <boost/math/tools/promotion.hpp>
+#include <boost/math/ccmath/isnan.hpp>
+
+namespace boost::math::ccmath {
+
+namespace detail {
+
+template <typename T>
+constexpr T fmax_impl(const T x, const T y) noexcept
+{
+    if (x > y)
+    {
+        return x;
+    }
+    else
+    {
+        return y;
+    }
+}
+
+} // Namespace detail
+
+template <typename Real, std::enable_if_t<!std::is_integral_v<Real>, bool> = true>
+constexpr Real fmax(Real x, Real y) noexcept
+{
+    if (BOOST_MATH_IS_CONSTANT_EVALUATED(x))
+    {
+        if (boost::math::ccmath::isnan(x))
+        {
+            return y;
+        }
+        else if (boost::math::ccmath::isnan(y))
+        {
+            return x;
+        }
+        
+        return boost::math::ccmath::detail::fmax_impl(x, y);
+    }
+    else
+    {
+        using std::fmax;
+        return fmax(x, y);
+    }
+}
+
+template <typename T1, typename T2>
+constexpr auto fmax(T1 x, T2 y) noexcept
+{
+    if (BOOST_MATH_IS_CONSTANT_EVALUATED(x))
+    {
+        using promoted_type = boost::math::tools::promote_args_2_t<T1, T2>;
+        return boost::math::ccmath::fmax(static_cast<promoted_type>(x), static_cast<promoted_type>(y));
+    }
+    else
+    {
+        using std::fmax;
+        return fmax(x, y);
+    }
+}
+
+constexpr float fmaxf(float x, float y) noexcept
+{
+    return boost::math::ccmath::fmax(x, y);
+}
+
+#ifndef BOOST_MATH_NO_LONG_DOUBLE_MATH_FUNCTIONS
+constexpr long double fmaxl(long double x, long double y) noexcept
+{
+    return boost::math::ccmath::fmax(x, y);
+}
+#endif
+
+} // Namespace boost::math::ccmath
+
+#endif // BOOST_MATH_CCMATH_FMAX_HPP