1 | // (C) Copyright Steve Cleary, Beman Dawes, Howard Hinnant & John Maddock 2000. |
2 | // Use, modification and distribution are subject to the Boost Software License, |
3 | // Version 1.0. (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/utility for most recent version including documentation. |
7 | |
8 | // call_traits: defines typedefs for function usage |
9 | // (see libs/utility/call_traits.htm) |
10 | |
11 | /* Release notes: |
12 | 23rd July 2000: |
13 | Fixed array specialization. (JM) |
14 | Added Borland specific fixes for reference types |
15 | (issue raised by Steve Cleary). |
16 | */ |
17 | |
18 | #ifndef BOOST_DETAIL_CALL_TRAITS_HPP |
19 | #define BOOST_DETAIL_CALL_TRAITS_HPP |
20 | |
21 | #ifndef BOOST_CONFIG_HPP |
22 | #include <boost/config.hpp> |
23 | #endif |
24 | #include <cstddef> |
25 | |
26 | #include <boost/type_traits/is_arithmetic.hpp> |
27 | #include <boost/type_traits/is_enum.hpp> |
28 | #include <boost/type_traits/is_pointer.hpp> |
29 | #include <boost/detail/workaround.hpp> |
30 | |
31 | namespace boost{ |
32 | |
33 | namespace detail{ |
34 | |
35 | template <typename T, bool small_> |
36 | struct ct_imp2 |
37 | { |
38 | typedef const T& param_type; |
39 | }; |
40 | |
41 | template <typename T> |
42 | struct ct_imp2<T, true> |
43 | { |
44 | typedef const T param_type; |
45 | }; |
46 | |
47 | template <typename T, bool isp, bool b1, bool b2> |
48 | struct ct_imp |
49 | { |
50 | typedef const T& param_type; |
51 | }; |
52 | |
53 | template <typename T, bool isp, bool b2> |
54 | struct ct_imp<T, isp, true, b2> |
55 | { |
56 | typedef typename ct_imp2<T, sizeof(T) <= sizeof(void*)>::param_type param_type; |
57 | }; |
58 | |
59 | template <typename T, bool isp, bool b1> |
60 | struct ct_imp<T, isp, b1, true> |
61 | { |
62 | typedef typename ct_imp2<T, sizeof(T) <= sizeof(void*)>::param_type param_type; |
63 | }; |
64 | |
65 | template <typename T, bool b1, bool b2> |
66 | struct ct_imp<T, true, b1, b2> |
67 | { |
68 | typedef const T param_type; |
69 | }; |
70 | |
71 | } |
72 | |
73 | template <typename T> |
74 | struct call_traits |
75 | { |
76 | public: |
77 | typedef T value_type; |
78 | typedef T& reference; |
79 | typedef const T& const_reference; |
80 | // |
81 | // C++ Builder workaround: we should be able to define a compile time |
82 | // constant and pass that as a single template parameter to ct_imp<T,bool>, |
83 | // however compiler bugs prevent this - instead pass three bool's to |
84 | // ct_imp<T,bool,bool,bool> and add an extra partial specialisation |
85 | // of ct_imp to handle the logic. (JM) |
86 | typedef typename boost::detail::ct_imp< |
87 | T, |
88 | ::boost::is_pointer<T>::value, |
89 | ::boost::is_arithmetic<T>::value, |
90 | ::boost::is_enum<T>::value |
91 | >::param_type param_type; |
92 | }; |
93 | |
94 | template <typename T> |
95 | struct call_traits<T&> |
96 | { |
97 | typedef T& value_type; |
98 | typedef T& reference; |
99 | typedef const T& const_reference; |
100 | typedef T& param_type; // hh removed const |
101 | }; |
102 | |
103 | #if BOOST_WORKAROUND( BOOST_BORLANDC, < 0x5A0 ) |
104 | // these are illegal specialisations; cv-qualifies applied to |
105 | // references have no effect according to [8.3.2p1], |
106 | // C++ Builder requires them though as it treats cv-qualified |
107 | // references as distinct types... |
108 | template <typename T> |
109 | struct call_traits<T&const> |
110 | { |
111 | typedef T& value_type; |
112 | typedef T& reference; |
113 | typedef const T& const_reference; |
114 | typedef T& param_type; // hh removed const |
115 | }; |
116 | template <typename T> |
117 | struct call_traits<T&volatile> |
118 | { |
119 | typedef T& value_type; |
120 | typedef T& reference; |
121 | typedef const T& const_reference; |
122 | typedef T& param_type; // hh removed const |
123 | }; |
124 | template <typename T> |
125 | struct call_traits<T&const volatile> |
126 | { |
127 | typedef T& value_type; |
128 | typedef T& reference; |
129 | typedef const T& const_reference; |
130 | typedef T& param_type; // hh removed const |
131 | }; |
132 | |
133 | template <typename T> |
134 | struct call_traits< T * > |
135 | { |
136 | typedef T * value_type; |
137 | typedef T * & reference; |
138 | typedef T * const & const_reference; |
139 | typedef T * const param_type; // hh removed const |
140 | }; |
141 | #endif |
142 | #if !defined(BOOST_NO_ARRAY_TYPE_SPECIALIZATIONS) |
143 | template <typename T, std::size_t N> |
144 | struct call_traits<T [N]> |
145 | { |
146 | private: |
147 | typedef T array_type[N]; |
148 | public: |
149 | // degrades array to pointer: |
150 | typedef const T* value_type; |
151 | typedef array_type& reference; |
152 | typedef const array_type& const_reference; |
153 | typedef const T* const param_type; |
154 | }; |
155 | |
156 | template <typename T, std::size_t N> |
157 | struct call_traits<const T [N]> |
158 | { |
159 | private: |
160 | typedef const T array_type[N]; |
161 | public: |
162 | // degrades array to pointer: |
163 | typedef const T* value_type; |
164 | typedef array_type& reference; |
165 | typedef const array_type& const_reference; |
166 | typedef const T* const param_type; |
167 | }; |
168 | #endif |
169 | |
170 | } |
171 | |
172 | #endif // BOOST_DETAIL_CALL_TRAITS_HPP |
173 | |