update boost

linx64/include/boost/describe/descriptor_by_pointer.hpp

@@ -0,0 +1,48 @@
+#ifndef BOOST_DESCRIBE_DESCRIPTOR_BY_POINTER_HPP_INCLUDED
+#define BOOST_DESCRIBE_DESCRIPTOR_BY_POINTER_HPP_INCLUDED
+
+// Copyright 2021 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#include <boost/describe/detail/config.hpp>
+
+#if defined(__cpp_nontype_template_parameter_auto) && __cpp_nontype_template_parameter_auto >= 201606L
+
+#include <boost/mp11/algorithm.hpp>
+#include <boost/mp11/bind.hpp>
+#include <boost/mp11/integral.hpp>
+
+namespace boost
+{
+namespace describe
+{
+
+namespace detail
+{
+
+template<class Pm> constexpr bool cx_pmeq( Pm p1, Pm p2 )
+{
+    return p1 == p2;
+}
+
+template<class Pm1, class Pm2> constexpr bool cx_pmeq( Pm1, Pm2 )
+{
+    return false;
+}
+
+template<auto Pm> struct match_by_pointer
+{
+    template<class D> using fn = mp11::mp_bool< cx_pmeq( D::pointer, Pm ) >;
+};
+
+} // namespace detail
+
+template<class L, auto Pm> using descriptor_by_pointer = mp11::mp_at<L, mp11::mp_find_if_q<L, detail::match_by_pointer<Pm>>>;
+
+} // namespace describe
+} // namespace boost
+
+#endif // __cpp_nontype_template_parameter_auto
+
+#endif // #ifndef BOOST_DESCRIBE_DESCRIPTOR_BY_POINTER_HPP_INCLUDED