Added thirdparty: boost library

thirdparty/include/boost/convert/detail/is_fun.hpp

@@ -0,0 +1,57 @@
+// Copyright (c) 2009-2020 Vladimir Batov.
+// Use, modification and distribution are subject to the Boost Software License,
+// Version 1.0. See http://www.boost.org/LICENSE_1_0.txt.
+
+#ifndef BOOST_CONVERT_IS_FUNCTION_HPP
+#define BOOST_CONVERT_IS_FUNCTION_HPP
+
+#include <boost/convert/detail/config.hpp>
+#include <boost/convert/detail/has_member.hpp>
+#include <boost/function_types/is_function_pointer.hpp>
+#include <boost/function_types/function_arity.hpp>
+#include <boost/function_types/result_type.hpp>
+
+namespace boost { namespace cnv
+{
+    using yes_type = ::boost::type_traits::yes_type;
+    using  no_type = ::boost::type_traits:: no_type;
+
+    template <bool has_operator, typename Functor, typename TypeOut>
+    struct check_functor { BOOST_STATIC_CONSTANT(bool, value = false); };
+
+    template<typename Func, typename TypeOut, typename Enable = void>
+    struct is_fun { BOOST_STATIC_CONSTANT(bool, value = false); };
+
+    template <typename Functor, typename TypeOut>
+    struct check_functor<true, Functor, TypeOut>
+    {
+        static yes_type test (TypeOut const&);
+        static no_type  test (...);
+
+        static bool BOOST_CONSTEXPR_OR_CONST value = sizeof(yes_type) == sizeof(test(((Functor*) 0)->operator()()));
+    };
+    template<typename Functor, typename TypeOut>
+    struct is_fun<Functor, TypeOut,
+        typename enable_if_c<std::is_class<Functor>::value && !is_convertible<Functor, TypeOut>::value, void>::type>
+    {
+        BOOST_DECLARE_HAS_MEMBER(has_funop, operator());
+
+        BOOST_STATIC_CONSTANT(bool, value = (check_functor<has_funop<Functor>::value, Functor, TypeOut>::value));
+    };
+    template<typename Function, typename TypeOut>
+    struct is_fun<Function, TypeOut,
+        typename enable_if_c<
+            function_types::is_function_pointer<Function>::value &&
+            function_types::function_arity<Function>::value == 0 &&
+            !is_same<Function, TypeOut>::value,
+        void>::type>
+    {
+        using  out_type = TypeOut;
+        using func_type = typename function_types::result_type<Function>::type;
+
+        BOOST_STATIC_CONSTANT(bool, value = (is_convertible<func_type, out_type>::value));
+    };
+}}
+
+#endif // BOOST_CONVERT_IS_FUNCTION_HPP
+