1 /* Copyright 2003-2017 Joaquin M Lopez Munoz.
2  * Distributed under the Boost Software License, Version 1.0.
3  * (See accompanying file LICENSE_1_0.txt or copy at
4  * http://www.boost.org/LICENSE_1_0.txt)
5  *
6  * See http://www.boost.org/libs/multi_index for library home page.
7  */
8 
9 #ifndef BOOST_MULTI_INDEX_DETAIL_PROMOTES_ARG_HPP
10 #define BOOST_MULTI_INDEX_DETAIL_PROMOTES_ARG_HPP
11 
12 #if defined(_MSC_VER)
13 #pragma once
14 #endif
15 
16 #include <boost/config.hpp> /* keep it first to prevent nasty warns in MSVC */
17 #include <boost/detail/workaround.hpp>
18 
19 /* Metafunctions to check if f(arg1,arg2) promotes either arg1 to the type of
20  * arg2 or viceversa. By default, (i.e. if it cannot be determined), no
21  * promotion is assumed.
22  */
23 
24 #if BOOST_WORKAROUND(BOOST_MSVC,<1400)
25 
26 namespace boost{
27 
28 namespace multi_index{
29 
30 namespace detail{
31 
32 template<typename F,typename Arg1,typename Arg2>
33 struct promotes_1st_arg:mpl::false_{};
34 
35 template<typename F,typename Arg1,typename Arg2>
36 struct promotes_2nd_arg:mpl::false_{};
37 
38 } /* namespace multi_index::detail */
39 
40 } /* namespace multi_index */
41 
42 } /* namespace boost */
43 
44 #else
45 
46 #include <boost/mpl/and.hpp>
47 #include <boost/mpl/bool.hpp>
48 #include <boost/mpl/not.hpp>
49 #include <boost/multi_index/detail/is_transparent.hpp>
50 #include <boost/type_traits/is_convertible.hpp>
51 
52 namespace boost{
53 
54 namespace multi_index{
55 
56 namespace detail{
57 
58 template<typename F,typename Arg1,typename Arg2>
59 struct promotes_1st_arg:
60   mpl::and_<
61     mpl::not_<is_transparent<F,Arg1,Arg2> >,
62     is_convertible<const Arg1,Arg2>,
63     is_transparent<F,Arg2,Arg2>
64   >
65 {};
66 
67 template<typename F,typename Arg1,typename Arg2>
68 struct promotes_2nd_arg:
69   mpl::and_<
70     mpl::not_<is_transparent<F,Arg1,Arg2> >,
71     is_convertible<const Arg2,Arg1>,
72     is_transparent<F,Arg1,Arg1>
73   >
74 {};
75 
76 } /* namespace multi_index::detail */
77 
78 } /* namespace multi_index */
79 
80 } /* namespace boost */
81 
82 #endif
83 #endif
84