1 | // -*- C++ -*- |
2 | |
3 | // Copyright (C) 2005, 2006, 2007, 2009 Free Software Foundation, Inc. |
4 | // |
5 | // This file is part of the GNU ISO C++ Library. This library is free |
6 | // software; you can redistribute it and/or modify it under the terms |
7 | // of the GNU General Public License as published by the Free Software |
8 | // Foundation; either version 3, or (at your option) any later |
9 | // version. |
10 | |
11 | // This library is distributed in the hope that it will be useful, but |
12 | // WITHOUT ANY WARRANTY; without even the implied warranty of |
13 | // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
14 | // General Public License for more details. |
15 | |
16 | // Under Section 7 of GPL version 3, you are granted additional |
17 | // permissions described in the GCC Runtime Library Exception, version |
18 | // 3.1, as published by the Free Software Foundation. |
19 | |
20 | // You should have received a copy of the GNU General Public License and |
21 | // a copy of the GCC Runtime Library Exception along with this program; |
22 | // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see |
23 | // <http://www.gnu.org/licenses/>. |
24 | |
25 | /** @file ext/type_traits.h |
26 | * This file is a GNU extension to the Standard C++ Library. |
27 | */ |
28 | |
29 | #ifndef _EXT_TYPE_TRAITS |
30 | #define _EXT_TYPE_TRAITS 1 |
31 | |
32 | #pragma GCC system_header |
33 | |
34 | #include <bits/c++config.h> |
35 | #include <bits/cpp_type_traits.h> |
36 | |
37 | namespace __gnu_cxx _GLIBCXX_VISIBILITY(default) |
38 | { |
39 | _GLIBCXX_BEGIN_NAMESPACE_VERSION |
40 | |
41 | // Define a nested type if some predicate holds. |
42 | template<bool, typename> |
43 | struct __enable_if |
44 | { }; |
45 | |
46 | template<typename _Tp> |
47 | struct __enable_if<true, _Tp> |
48 | { typedef _Tp __type; }; |
49 | |
50 | |
51 | // Conditional expression for types. If true, first, if false, second. |
52 | template<bool _Cond, typename _Iftrue, typename _Iffalse> |
53 | struct __conditional_type |
54 | { typedef _Iftrue __type; }; |
55 | |
56 | template<typename _Iftrue, typename _Iffalse> |
57 | struct __conditional_type<false, _Iftrue, _Iffalse> |
58 | { typedef _Iffalse __type; }; |
59 | |
60 | |
61 | // Given an integral builtin type, return the corresponding unsigned type. |
62 | template<typename _Tp> |
63 | struct __add_unsigned |
64 | { |
65 | private: |
66 | typedef __enable_if<std::__is_integer<_Tp>::__value, _Tp> __if_type; |
67 | |
68 | public: |
69 | typedef typename __if_type::__type __type; |
70 | }; |
71 | |
72 | template<> |
73 | struct __add_unsigned<char> |
74 | { typedef unsigned char __type; }; |
75 | |
76 | template<> |
77 | struct __add_unsigned<signed char> |
78 | { typedef unsigned char __type; }; |
79 | |
80 | template<> |
81 | struct __add_unsigned<short> |
82 | { typedef unsigned short __type; }; |
83 | |
84 | template<> |
85 | struct __add_unsigned<int> |
86 | { typedef unsigned int __type; }; |
87 | |
88 | template<> |
89 | struct __add_unsigned<long> |
90 | { typedef unsigned long __type; }; |
91 | |
92 | template<> |
93 | struct __add_unsigned<long long> |
94 | { typedef unsigned long long __type; }; |
95 | |
96 | // Declare but don't define. |
97 | template<> |
98 | struct __add_unsigned<bool>; |
99 | |
100 | template<> |
101 | struct __add_unsigned<wchar_t>; |
102 | |
103 | |
104 | // Given an integral builtin type, return the corresponding signed type. |
105 | template<typename _Tp> |
106 | struct __remove_unsigned |
107 | { |
108 | private: |
109 | typedef __enable_if<std::__is_integer<_Tp>::__value, _Tp> __if_type; |
110 | |
111 | public: |
112 | typedef typename __if_type::__type __type; |
113 | }; |
114 | |
115 | template<> |
116 | struct __remove_unsigned<char> |
117 | { typedef signed char __type; }; |
118 | |
119 | template<> |
120 | struct __remove_unsigned<unsigned char> |
121 | { typedef signed char __type; }; |
122 | |
123 | template<> |
124 | struct __remove_unsigned<unsigned short> |
125 | { typedef short __type; }; |
126 | |
127 | template<> |
128 | struct __remove_unsigned<unsigned int> |
129 | { typedef int __type; }; |
130 | |
131 | template<> |
132 | struct __remove_unsigned<unsigned long> |
133 | { typedef long __type; }; |
134 | |
135 | template<> |
136 | struct __remove_unsigned<unsigned long long> |
137 | { typedef long long __type; }; |
138 | |
139 | // Declare but don't define. |
140 | template<> |
141 | struct __remove_unsigned<bool>; |
142 | |
143 | template<> |
144 | struct __remove_unsigned<wchar_t>; |
145 | |
146 | |
147 | // For use in string and vstring. |
148 | template<typename _Type> |
149 | inline bool |
150 | __is_null_pointer(_Type* __ptr) |
151 | { return __ptr == 0; } |
152 | |
153 | template<typename _Type> |
154 | inline bool |
155 | __is_null_pointer(_Type) |
156 | { return false; } |
157 | |
158 | |
159 | // For complex and cmath |
160 | template<typename _Tp, bool = std::__is_integer<_Tp>::__value> |
161 | struct __promote |
162 | { typedef double __type; }; |
163 | |
164 | // No nested __type member for non-integer non-floating point types, |
165 | // allows this type to be used for SFINAE to constrain overloads in |
166 | // <cmath> and <complex> to only the intended types. |
167 | template<typename _Tp> |
168 | struct __promote<_Tp, false> |
169 | { }; |
170 | |
171 | template<> |
172 | struct __promote<long double> |
173 | { typedef long double __type; }; |
174 | |
175 | template<> |
176 | struct __promote<double> |
177 | { typedef double __type; }; |
178 | |
179 | template<> |
180 | struct __promote<float> |
181 | { typedef float __type; }; |
182 | |
183 | template<typename _Tp, typename _Up, |
184 | typename _Tp2 = typename __promote<_Tp>::__type, |
185 | typename _Up2 = typename __promote<_Up>::__type> |
186 | struct __promote_2 |
187 | { |
188 | typedef __typeof__(_Tp2() + _Up2()) __type; |
189 | }; |
190 | |
191 | template<typename _Tp, typename _Up, typename _Vp, |
192 | typename _Tp2 = typename __promote<_Tp>::__type, |
193 | typename _Up2 = typename __promote<_Up>::__type, |
194 | typename _Vp2 = typename __promote<_Vp>::__type> |
195 | struct __promote_3 |
196 | { |
197 | typedef __typeof__(_Tp2() + _Up2() + _Vp2()) __type; |
198 | }; |
199 | |
200 | template<typename _Tp, typename _Up, typename _Vp, typename _Wp, |
201 | typename _Tp2 = typename __promote<_Tp>::__type, |
202 | typename _Up2 = typename __promote<_Up>::__type, |
203 | typename _Vp2 = typename __promote<_Vp>::__type, |
204 | typename _Wp2 = typename __promote<_Wp>::__type> |
205 | struct __promote_4 |
206 | { |
207 | typedef __typeof__(_Tp2() + _Up2() + _Vp2() + _Wp2()) __type; |
208 | }; |
209 | |
210 | _GLIBCXX_END_NAMESPACE_VERSION |
211 | } // namespace |
212 | |
213 | #endif |
214 | |