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1 : // -*- C++ -*-
2 :
3 : // Copyright (C) 2005-2018 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 : extern "C++" {
38 :
39 : namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)
40 : {
41 : _GLIBCXX_BEGIN_NAMESPACE_VERSION
42 :
43 : // Define a nested type if some predicate holds.
44 : template<bool, typename>
45 : struct __enable_if
46 : { };
47 :
48 : template<typename _Tp>
49 : struct __enable_if<true, _Tp>
50 : { typedef _Tp __type; };
51 :
52 :
53 : // Conditional expression for types. If true, first, if false, second.
54 : template<bool _Cond, typename _Iftrue, typename _Iffalse>
55 : struct __conditional_type
56 : { typedef _Iftrue __type; };
57 :
58 : template<typename _Iftrue, typename _Iffalse>
59 : struct __conditional_type<false, _Iftrue, _Iffalse>
60 : { typedef _Iffalse __type; };
61 :
62 :
63 : // Given an integral builtin type, return the corresponding unsigned type.
64 : template<typename _Tp>
65 : struct __add_unsigned
66 : {
67 : private:
68 : typedef __enable_if<std::__is_integer<_Tp>::__value, _Tp> __if_type;
69 :
70 : public:
71 : typedef typename __if_type::__type __type;
72 : };
73 :
74 : template<>
75 : struct __add_unsigned<char>
76 : { typedef unsigned char __type; };
77 :
78 : template<>
79 : struct __add_unsigned<signed char>
80 : { typedef unsigned char __type; };
81 :
82 : template<>
83 : struct __add_unsigned<short>
84 : { typedef unsigned short __type; };
85 :
86 : template<>
87 : struct __add_unsigned<int>
88 : { typedef unsigned int __type; };
89 :
90 : template<>
91 : struct __add_unsigned<long>
92 : { typedef unsigned long __type; };
93 :
94 : template<>
95 : struct __add_unsigned<long long>
96 : { typedef unsigned long long __type; };
97 :
98 : // Declare but don't define.
99 : template<>
100 : struct __add_unsigned<bool>;
101 :
102 : template<>
103 : struct __add_unsigned<wchar_t>;
104 :
105 :
106 : // Given an integral builtin type, return the corresponding signed type.
107 : template<typename _Tp>
108 : struct __remove_unsigned
109 : {
110 : private:
111 : typedef __enable_if<std::__is_integer<_Tp>::__value, _Tp> __if_type;
112 :
113 : public:
114 : typedef typename __if_type::__type __type;
115 : };
116 :
117 : template<>
118 : struct __remove_unsigned<char>
119 : { typedef signed char __type; };
120 :
121 : template<>
122 : struct __remove_unsigned<unsigned char>
123 : { typedef signed char __type; };
124 :
125 : template<>
126 : struct __remove_unsigned<unsigned short>
127 : { typedef short __type; };
128 :
129 : template<>
130 : struct __remove_unsigned<unsigned int>
131 : { typedef int __type; };
132 :
133 : template<>
134 : struct __remove_unsigned<unsigned long>
135 : { typedef long __type; };
136 :
137 : template<>
138 : struct __remove_unsigned<unsigned long long>
139 : { typedef long long __type; };
140 :
141 : // Declare but don't define.
142 : template<>
143 : struct __remove_unsigned<bool>;
144 :
145 : template<>
146 : struct __remove_unsigned<wchar_t>;
147 :
148 :
149 : // For use in string and vstring.
150 : template<typename _Type>
151 : inline bool
152 1017748 : __is_null_pointer(_Type* __ptr)
153 1017748 : { return __ptr == 0; }
154 :
155 : template<typename _Type>
156 : inline bool
157 : __is_null_pointer(_Type)
158 : { return false; }
159 :
160 : #if __cplusplus >= 201103L
161 : inline bool
162 : __is_null_pointer(std::nullptr_t)
163 : { return true; }
164 : #endif
165 :
166 : // For complex and cmath
167 : template<typename _Tp, bool = std::__is_integer<_Tp>::__value>
168 : struct __promote
169 : { typedef double __type; };
170 :
171 : // No nested __type member for non-integer non-floating point types,
172 : // allows this type to be used for SFINAE to constrain overloads in
173 : // <cmath> and <complex> to only the intended types.
174 : template<typename _Tp>
175 : struct __promote<_Tp, false>
176 : { };
177 :
178 : template<>
179 : struct __promote<long double>
180 : { typedef long double __type; };
181 :
182 : template<>
183 : struct __promote<double>
184 : { typedef double __type; };
185 :
186 : template<>
187 : struct __promote<float>
188 : { typedef float __type; };
189 :
190 : template<typename _Tp, typename _Up,
191 : typename _Tp2 = typename __promote<_Tp>::__type,
192 : typename _Up2 = typename __promote<_Up>::__type>
193 : struct __promote_2
194 : {
195 : typedef __typeof__(_Tp2() + _Up2()) __type;
196 : };
197 :
198 : template<typename _Tp, typename _Up, typename _Vp,
199 : typename _Tp2 = typename __promote<_Tp>::__type,
200 : typename _Up2 = typename __promote<_Up>::__type,
201 : typename _Vp2 = typename __promote<_Vp>::__type>
202 : struct __promote_3
203 : {
204 : typedef __typeof__(_Tp2() + _Up2() + _Vp2()) __type;
205 : };
206 :
207 : template<typename _Tp, typename _Up, typename _Vp, typename _Wp,
208 : typename _Tp2 = typename __promote<_Tp>::__type,
209 : typename _Up2 = typename __promote<_Up>::__type,
210 : typename _Vp2 = typename __promote<_Vp>::__type,
211 : typename _Wp2 = typename __promote<_Wp>::__type>
212 : struct __promote_4
213 : {
214 : typedef __typeof__(_Tp2() + _Up2() + _Vp2() + _Wp2()) __type;
215 : };
216 :
217 : _GLIBCXX_END_NAMESPACE_VERSION
218 : } // namespace
219 : } // extern "C++"
220 :
221 : #endif
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