Added thirdparty: boost library

thirdparty/include/boost/variant/detail/apply_visitor_unary.hpp

@@ -0,0 +1,127 @@
+//-----------------------------------------------------------------------------
+// boost variant/detail/apply_visitor_unary.hpp header file
+// See http://www.boost.org for updates, documentation, and revision history.
+//-----------------------------------------------------------------------------
+//
+// Copyright (c) 2002-2003 Eric Friedman
+// Copyright (c) 2014-2023 Antony Polukhin
+//
+// Distributed under 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_VARIANT_DETAIL_APPLY_VISITOR_UNARY_HPP
+#define BOOST_VARIANT_DETAIL_APPLY_VISITOR_UNARY_HPP
+
+#include <boost/config.hpp>
+#include <utility>
+
+#if !defined(BOOST_NO_CXX14_DECLTYPE_AUTO) && !defined(BOOST_NO_CXX11_DECLTYPE_N3276)
+#   include <boost/mpl/distance.hpp>
+#   include <boost/mpl/advance.hpp>
+#   include <boost/mpl/deref.hpp>
+#   include <boost/mpl/size.hpp>
+#   include <boost/utility/declval.hpp>
+#   include <boost/core/enable_if.hpp>
+#   include <boost/type_traits/copy_cv_ref.hpp>
+#   include <boost/type_traits/remove_reference.hpp>
+#   include <boost/variant/detail/has_result_type.hpp>
+#endif
+
+namespace boost {
+
+//////////////////////////////////////////////////////////////////////////
+// function template apply_visitor(visitor, visitable)
+//
+// Visits visitable with visitor.
+//
+
+//
+// nonconst-visitor version:
+//
+
+template <typename Visitor, typename Visitable>
+inline typename Visitor::result_type
+apply_visitor(Visitor& visitor, Visitable&& visitable)
+{
+    return std::forward<Visitable>(visitable).apply_visitor(visitor);
+}
+
+//
+// const-visitor version:
+//
+
+template <typename Visitor, typename Visitable>
+inline typename Visitor::result_type
+apply_visitor(const Visitor& visitor, Visitable&& visitable)
+{
+    return std::forward<Visitable>(visitable).apply_visitor(visitor);
+}
+
+
+#if !defined(BOOST_NO_CXX14_DECLTYPE_AUTO) && !defined(BOOST_NO_CXX11_DECLTYPE_N3276)
+#define BOOST_VARIANT_HAS_DECLTYPE_APPLY_VISITOR_RETURN_TYPE
+
+// C++14
+namespace detail { namespace variant {
+
+// This class serves only metaprogramming purposes. none of its methods must be called at runtime!
+template <class Visitor, class Variant>
+struct result_multideduce1 {
+    typedef typename remove_reference<Variant>::type::types types;
+    typedef typename boost::mpl::begin<types>::type begin_it;
+    typedef typename boost::mpl::advance<
+        begin_it, boost::mpl::int_<boost::mpl::size<types>::type::value - 1>
+    >::type                                         last_it;
+
+    template <class It, class Dummy = void> // avoid explicit specialization in class scope
+    struct deduce_impl {
+        typedef typename boost::mpl::next<It>::type next_t;
+        typedef typename boost::mpl::deref<It>::type value_t;
+        typedef decltype(true ? boost::declval< Visitor& >()( boost::declval< copy_cv_ref_t< value_t, Variant > >() )
+                              : boost::declval< typename deduce_impl<next_t>::type >()) type;
+    };
+
+    template <class Dummy>
+    struct deduce_impl<last_it, Dummy> {
+        typedef typename boost::mpl::deref<last_it>::type value_t;
+        typedef decltype(boost::declval< Visitor& >()( boost::declval< copy_cv_ref_t< value_t, Variant > >() )) type;
+    };
+
+    typedef typename deduce_impl<begin_it>::type type;
+};
+
+template <class Visitor, class Variant>
+struct result_wrapper1
+{
+    typedef typename result_multideduce1<Visitor, Variant>::type result_type;
+
+    Visitor&& visitor_;
+    explicit result_wrapper1(Visitor&& visitor) BOOST_NOEXCEPT
+        : visitor_(std::forward<Visitor>(visitor))
+    {}
+
+    template <class T>
+    result_type operator()(T&& val) const {
+        return visitor_(std::forward<T>(val));
+    }
+};
+
+}} // namespace detail::variant
+
+template <typename Visitor, typename Visitable>
+inline decltype(auto) apply_visitor(Visitor&& visitor, Visitable&& visitable,
+    typename boost::disable_if<
+        boost::detail::variant::has_result_type<Visitor>,
+        bool
+    >::type = true)
+{
+    boost::detail::variant::result_wrapper1<Visitor, Visitable> cpp14_vis(std::forward<Visitor>(visitor));
+    return std::forward<Visitable>(visitable).apply_visitor(cpp14_vis);
+}
+
+#endif // !defined(BOOST_NO_CXX14_DECLTYPE_AUTO) && !defined(BOOST_NO_CXX11_DECLTYPE_N3276)
+
+} // namespace boost
+
+#endif // BOOST_VARIANT_DETAIL_APPLY_VISITOR_UNARY_HPP