1// Copyright (c) 2009-2014 Vladimir Batov.
2// Use, modification and distribution are subject to the Boost Software License,
3// Version 1.0. See http://www.boost.org/LICENSE_1_0.txt.
4
5#ifndef BOOST_CONVERT_IS_FUNCTION_HPP
6#define BOOST_CONVERT_IS_FUNCTION_HPP
7
8#include <boost/convert/detail/forward.hpp>
9#include <boost/convert/detail/has_member.hpp>
10#include <boost/utility/enable_if.hpp>
11#include <boost/type_traits.hpp>
12#include <boost/function_types/is_function_pointer.hpp>
13#include <boost/function_types/function_arity.hpp>
14#include <boost/function_types/result_type.hpp>
15
16namespace boost { namespace cnv
17{
18 typedef ::boost::type_traits::yes_type yes_type;
19 typedef ::boost::type_traits:: no_type no_type;
20
21 template <bool has_operator, typename Functor, typename TypeOut>
22 struct check_functor { BOOST_STATIC_CONSTANT(bool, value = false); };
23
24 template<typename Func, typename TypeOut, class Enable =void>
25 struct is_fun { BOOST_STATIC_CONSTANT(bool, value = false); };
26
27 template <typename Functor, typename TypeOut>
28 struct check_functor<true, Functor, TypeOut>
29 {
30 static yes_type test (TypeOut const&);
31 static no_type test (...);
32
33 static const bool value = sizeof(yes_type) == sizeof(test(((Functor*) 0)->operator()()));
34 };
35
36 template<typename Functor, typename TypeOut>
37 struct is_fun<Functor, TypeOut,
38 typename enable_if_c<is_class<Functor>::value && !is_convertible<Functor, TypeOut>::value, void>::type>
39 {
40 BOOST_DECLARE_HAS_MEMBER(has_funop, operator());
41
42 BOOST_STATIC_CONSTANT(bool, value = (check_functor<has_funop<Functor>::value, Functor, TypeOut>::value));
43 };
44
45 template<typename Function, typename TypeOut>
46 struct is_fun<Function, TypeOut,
47 typename enable_if_c<
48 function_types::is_function_pointer<Function>::value &&
49 function_types::function_arity<Function>::value == 0 &&
50 !is_same<Function, TypeOut>::value,
51 void>::type>
52 {
53 typedef TypeOut out_type;
54 typedef typename function_types::result_type<Function>::type func_out_type;
55
56 BOOST_STATIC_CONSTANT(bool, value = (is_convertible<func_out_type, out_type>::value));
57 };
58}}
59
60#endif // BOOST_CONVERT_IS_FUNCTION_HPP
61
62

source code of boost/boost/convert/detail/is_fun.hpp