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1 : // -*- C++ -*-
2 :
3 : // Copyright (C) 2005-2013 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 1291473 : __is_null_pointer(_Type* __ptr)
151 1291473 : { 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
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