1// (C) Copyright 2009-2011 Frederic Bron.
2//
3// Use, modification and distribution are subject to the Boost Software License,
4// Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
5// http://www.boost.org/LICENSE_1_0.txt).
6//
7// See http://www.boost.org/libs/type_traits for most recent version including documentation.
8
9#ifndef BOOST_TT_HAS_PLUS_ASSIGN_HPP_INCLUDED
10#define BOOST_TT_HAS_PLUS_ASSIGN_HPP_INCLUDED
11
12#include <boost/config.hpp>
13#include <boost/type_traits/detail/config.hpp>
14
15// cannot include this header without getting warnings of the kind:
16// gcc:
17// warning: value computed is not used
18// warning: comparison between signed and unsigned integer expressions
19// msvc:
20// warning C4018: '<' : signed/unsigned mismatch
21// warning C4244: '+=' : conversion from 'double' to 'char', possible loss of data
22// warning C4547: '*' : operator before comma has no effect; expected operator with side-effect
23// warning C4800: 'int' : forcing value to bool 'true' or 'false' (performance warning)
24// warning C4804: '<' : unsafe use of type 'bool' in operation
25// warning C4805: '==' : unsafe mix of type 'bool' and type 'char' in operation
26// cannot find another implementation -> declared as system header to suppress these warnings.
27#if defined(__GNUC__)
28# pragma GCC system_header
29#elif defined(BOOST_MSVC)
30# pragma warning ( push )
31# pragma warning ( disable : 4018 4244 4547 4800 4804 4805 4913 4133)
32# if BOOST_WORKAROUND(BOOST_MSVC_FULL_VER, >= 140050000)
33# pragma warning ( disable : 6334)
34# endif
35#endif
36
37#if defined(BOOST_TT_HAS_ACCURATE_BINARY_OPERATOR_DETECTION)
38
39#include <boost/type_traits/integral_constant.hpp>
40#include <boost/type_traits/make_void.hpp>
41#include <boost/type_traits/is_convertible.hpp>
42#include <boost/type_traits/is_void.hpp>
43#include <boost/type_traits/is_same.hpp>
44#include <boost/type_traits/is_pointer.hpp>
45#include <boost/type_traits/is_arithmetic.hpp>
46#include <boost/type_traits/add_reference.hpp>
47#include <boost/type_traits/remove_pointer.hpp>
48#include <boost/type_traits/remove_reference.hpp>
49#include <boost/type_traits/remove_cv.hpp>
50#include <utility>
51
52namespace boost
53{
54
55 namespace binary_op_detail {
56
57 struct dont_care;
58
59 template <class T, class U, class Ret, class = void>
60 struct has_plus_assign_ret_imp : public boost::false_type {};
61
62 template <class T, class U, class Ret>
63 struct has_plus_assign_ret_imp<T, U, Ret, typename boost::make_void<decltype(std::declval<typename add_reference<T>::type>() += std::declval<typename add_reference<U>::type>())>::type>
64 : public boost::integral_constant<bool, ::boost::is_convertible<decltype(std::declval<typename add_reference<T>::type>() += std::declval<typename add_reference<U>::type>()), Ret>::value> {};
65
66 template <class T, class U, class = void >
67 struct has_plus_assign_void_imp : public boost::false_type {};
68
69 template <class T, class U>
70 struct has_plus_assign_void_imp<T, U, typename boost::make_void<decltype(std::declval<typename add_reference<T>::type>() += std::declval<typename add_reference<U>::type>())>::type>
71 : public boost::integral_constant<bool, ::boost::is_void<decltype(std::declval<typename add_reference<T>::type>() += std::declval<typename add_reference<U>::type>())>::value> {};
72
73 template <class T, class U, class = void>
74 struct has_plus_assign_dc_imp : public boost::false_type {};
75
76 template <class T, class U>
77 struct has_plus_assign_dc_imp<T, U, typename boost::make_void<decltype(std::declval<typename add_reference<T>::type>() += std::declval<typename add_reference<U>::type>())>::type>
78 : public boost::true_type {};
79
80 template <class T, class U, class Ret>
81 struct has_plus_assign_filter_ret : public boost::binary_op_detail:: has_plus_assign_ret_imp <T, U, Ret> {};
82 template <class T, class U>
83 struct has_plus_assign_filter_ret<T, U, void> : public boost::binary_op_detail:: has_plus_assign_void_imp <T, U> {};
84 template <class T, class U>
85 struct has_plus_assign_filter_ret<T, U, boost::binary_op_detail::dont_care> : public boost::binary_op_detail:: has_plus_assign_dc_imp <T, U> {};
86
87 template <class T, class U, class Ret, bool f>
88 struct has_plus_assign_filter_impossible : public boost::binary_op_detail:: has_plus_assign_filter_ret <T, U, Ret> {};
89 template <class T, class U, class Ret>
90 struct has_plus_assign_filter_impossible<T, U, Ret, true> : public boost::false_type {};
91
92 }
93
94 template <class T, class U = T, class Ret = boost::binary_op_detail::dont_care>
95 struct has_plus_assign : public boost::binary_op_detail:: has_plus_assign_filter_impossible <T, U, Ret, boost::is_arithmetic<typename boost::remove_reference<T>::type>::value && boost::is_pointer<typename remove_reference<U>::type>::value && !boost::is_same<bool, typename boost::remove_cv<typename remove_reference<T>::type>::type>::value> {};
96
97}
98
99#else
100
101#define BOOST_TT_TRAIT_NAME has_plus_assign
102#define BOOST_TT_TRAIT_OP +=
103#define BOOST_TT_FORBIDDEN_IF\
104 (\
105 /* Lhs==pointer and Rhs==pointer */\
106 (\
107 ::boost::is_pointer< Lhs_noref >::value && \
108 ::boost::is_pointer< Rhs_noref >::value\
109 ) || \
110 /* Lhs==void* and Rhs==fundamental */\
111 (\
112 ::boost::is_pointer< Lhs_noref >::value && \
113 ::boost::is_void< Lhs_noptr >::value && \
114 ::boost::is_fundamental< Rhs_nocv >::value\
115 ) || \
116 /* Rhs==void* and Lhs==fundamental */\
117 (\
118 ::boost::is_pointer< Rhs_noref >::value && \
119 ::boost::is_void< Rhs_noptr >::value && \
120 ::boost::is_fundamental< Lhs_nocv >::value\
121 ) || \
122 /* Lhs==pointer and Rhs==fundamental and Rhs!=integral */\
123 (\
124 ::boost::is_pointer< Lhs_noref >::value && \
125 ::boost::is_fundamental< Rhs_nocv >::value && \
126 (! ::boost::is_integral< Rhs_noref >::value )\
127 ) || \
128 /* Rhs==pointer and Lhs==fundamental and Lhs!=bool */\
129 (\
130 ::boost::is_pointer< Rhs_noref >::value && \
131 ::boost::is_fundamental< Lhs_nocv >::value && \
132 (! ::boost::is_same< Lhs_nocv, bool >::value )\
133 ) || \
134 /* (Lhs==fundamental or Lhs==pointer) and (Rhs==fundamental or Rhs==pointer) and (Lhs==const) */\
135 (\
136 (\
137 ::boost::is_fundamental< Lhs_nocv >::value || \
138 ::boost::is_pointer< Lhs_noref >::value\
139 ) && \
140 ( \
141 ::boost::is_fundamental< Rhs_nocv >::value || \
142 ::boost::is_pointer< Rhs_noref >::value\
143 ) && \
144 ::boost::is_const< Lhs_noref >::value\
145 )\
146 )
147
148
149#include <boost/type_traits/detail/has_binary_operator.hpp>
150
151#undef BOOST_TT_TRAIT_NAME
152#undef BOOST_TT_TRAIT_OP
153#undef BOOST_TT_FORBIDDEN_IF
154
155#endif
156
157#if defined(BOOST_MSVC)
158# pragma warning (pop)
159#endif
160
161#endif
162

source code of include/boost/type_traits/has_plus_assign.hpp