update ceph source to reef 18.1.2

[ceph.git] / ceph / src / boost / boost / math / ccmath / abs.hpp

diff --git a/ceph/src/boost/boost/math/ccmath/abs.hpp b/ceph/src/boost/boost/math/ccmath/abs.hpp
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+//  (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)
+//
+//  Constepxr implementation of abs (see c.math.abs secion 26.8.2 of the ISO standard)
+
+#ifndef BOOST_MATH_CCMATH_ABS
+#define BOOST_MATH_CCMATH_ABS
+
+#include <cmath>
+#include <type_traits>
+#include <limits>
+#include <boost/math/tools/is_constant_evaluated.hpp>
+#include <boost/math/ccmath/isnan.hpp>
+#include <boost/math/ccmath/isinf.hpp>
+
+namespace boost::math::ccmath {
+
+namespace detail {
+
+template <typename T> 
+inline constexpr T abs_impl(T x) noexcept
+{
+    return boost::math::ccmath::isnan(x) ? std::numeric_limits<T>::quiet_NaN() : 
+           boost::math::ccmath::isinf(x) ? std::numeric_limits<T>::infinity() : 
+           x == -0 ? T(0) :
+           x == (std::numeric_limits<T>::min)() ? std::numeric_limits<T>::quiet_NaN() : 
+           x > 0 ? x : -x;
+}
+
+} // Namespace detail
+
+template <typename T, std::enable_if_t<!std::is_unsigned_v<T>, bool> = true>
+inline constexpr T abs(T x) noexcept
+{
+    if(BOOST_MATH_IS_CONSTANT_EVALUATED(x))
+    {
+        return detail::abs_impl<T>(x);
+    }
+    else
+    {
+        using std::abs;
+        return abs(x);
+    }
+}
+
+// If abs() is called with an argument of type X for which is_unsigned_v<X> is true and if X
+// cannot be converted to int by integral promotion (7.3.7), the program is ill-formed.
+template <typename T, std::enable_if_t<std::is_unsigned_v<T>, bool> = true>
+inline constexpr T abs(T x) noexcept
+{
+    if constexpr (std::is_convertible_v<T, int>)
+    {
+        return detail::abs_impl<int>(static_cast<int>(x));
+    }
+    else
+    {
+        static_assert(sizeof(T) == 0, "Taking the absolute value of an unsigned value not covertible to int is UB.");
+        return T(0); // Unreachable, but suppresses warnings
+    }
+}
+
+inline constexpr long int labs(long int j) noexcept
+{
+    return boost::math::ccmath::abs(j);
+}
+
+inline constexpr long long int llabs(long long int j) noexcept
+{
+    return boost::math::ccmath::abs(j);
+}
+
+} // Namespaces
+
+#endif // BOOST_MATH_CCMATH_ABS