1// -*- C++ -*-
2
3// Copyright (C) 2005-2015 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
37namespace __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#if __cplusplus >= 201103L
159 inline bool
160 __is_null_pointer(std::nullptr_t)
161 { return true; }
162#endif
163
164 // For complex and cmath
165 template<typename _Tp, bool = std::__is_integer<_Tp>::__value>
166 struct __promote
167 { typedef double __type; };
168
169 // No nested __type member for non-integer non-floating point types,
170 // allows this type to be used for SFINAE to constrain overloads in
171 // <cmath> and <complex> to only the intended types.
172 template<typename _Tp>
173 struct __promote<_Tp, false>
174 { };
175
176 template<>
177 struct __promote<long double>
178 { typedef long double __type; };
179
180 template<>
181 struct __promote<double>
182 { typedef double __type; };
183
184 template<>
185 struct __promote<float>
186 { typedef float __type; };
187
188 template<typename _Tp, typename _Up,
189 typename _Tp2 = typename __promote<_Tp>::__type,
190 typename _Up2 = typename __promote<_Up>::__type>
191 struct __promote_2
192 {
193 typedef __typeof__(_Tp2() + _Up2()) __type;
194 };
195
196 template<typename _Tp, typename _Up, typename _Vp,
197 typename _Tp2 = typename __promote<_Tp>::__type,
198 typename _Up2 = typename __promote<_Up>::__type,
199 typename _Vp2 = typename __promote<_Vp>::__type>
200 struct __promote_3
201 {
202 typedef __typeof__(_Tp2() + _Up2() + _Vp2()) __type;
203 };
204
205 template<typename _Tp, typename _Up, typename _Vp, typename _Wp,
206 typename _Tp2 = typename __promote<_Tp>::__type,
207 typename _Up2 = typename __promote<_Up>::__type,
208 typename _Vp2 = typename __promote<_Vp>::__type,
209 typename _Wp2 = typename __promote<_Wp>::__type>
210 struct __promote_4
211 {
212 typedef __typeof__(_Tp2() + _Up2() + _Vp2() + _Wp2()) __type;
213 };
214
215_GLIBCXX_END_NAMESPACE_VERSION
216} // namespace
217
218#endif
219