Added thirdparty: boost library

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

@@ -0,0 +1,86 @@
+//  (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_LOGB_HPP
+#define BOOST_MATH_CCMATH_LOGB_HPP
+
+#include <boost/math/ccmath/detail/config.hpp>
+
+#ifdef BOOST_MATH_NO_CCMATH
+#error "The header <boost/math/logb.hpp> can only be used in C++17 and later."
+#endif
+
+#include <boost/math/ccmath/frexp.hpp>
+#include <boost/math/ccmath/isinf.hpp>
+#include <boost/math/ccmath/isnan.hpp>
+#include <boost/math/ccmath/abs.hpp>
+
+namespace boost::math::ccmath {
+
+namespace detail {
+
+// The value of the exponent returned by std::logb is always 1 less than the exponent returned by 
+// std::frexp because of the different normalization requirements: for the exponent e returned by std::logb, 
+// |arg*r^-e| is between 1 and r (typically between 1 and 2), but for the exponent e returned by std::frexp, 
+// |arg*2^-e| is between 0.5 and 1. 
+template <typename T>
+constexpr T logb_impl(T arg) noexcept
+{
+    int exp = 0;
+    boost::math::ccmath::frexp(arg, &exp);
+
+    return static_cast<T>(exp - 1);
+}
+
+} // Namespace detail
+
+template <typename Real, std::enable_if_t<!std::is_integral_v<Real>, bool> = true>
+constexpr Real logb(Real arg) noexcept
+{
+    if(BOOST_MATH_IS_CONSTANT_EVALUATED(arg))
+    {
+        if (boost::math::ccmath::abs(arg) == Real(0))
+        {
+            return -std::numeric_limits<Real>::infinity();
+        }
+        else if (boost::math::ccmath::isinf(arg))
+        {
+            return std::numeric_limits<Real>::infinity();
+        }
+        else if (boost::math::ccmath::isnan(arg))
+        {
+            return arg;
+        }
+        
+        return boost::math::ccmath::detail::logb_impl(arg);
+    }
+    else
+    {
+        using std::logb;
+        return logb(arg);
+    }
+}
+
+template <typename Z, std::enable_if_t<std::is_integral_v<Z>, bool> = true>
+constexpr double logb(Z arg) noexcept
+{
+    return boost::math::ccmath::logb(static_cast<double>(arg));
+}
+
+constexpr float logbf(float arg) noexcept
+{
+    return boost::math::ccmath::logb(arg);
+}
+
+#ifndef BOOST_MATH_NO_LONG_DOUBLE_MATH_FUNCTIONS
+constexpr long double logbl(long double arg) noexcept
+{
+    return boost::math::ccmath::logb(arg);
+}
+#endif
+
+} // Namespaces
+
+#endif // BOOST_MATH_CCMATH_LOGB_HPP