1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
| // The -*- C++ -*- type traits classes for internal use in libstdc++
// Copyright (C) 2000-2017 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library. This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 3, or (at your option)
// any later version.
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
// Under Section 7 of GPL version 3, you are granted additional
// permissions described in the GCC Runtime Library Exception, version
// 3.1, as published by the Free Software Foundation.
// You should have received a copy of the GNU General Public License and
// a copy of the GCC Runtime Library Exception along with this program;
// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
// <http://www.gnu.org/licenses/>.
/** @file bits/cpp_type_traits.h
* This is an internal header file, included by other library headers.
* Do not attempt to use it directly. @headername{ext/type_traits}
*/
// Written by Gabriel Dos Reis <dosreis@cmla.ens-cachan.fr>
#ifndef _CPP_TYPE_TRAITS_H
#define _CPP_TYPE_TRAITS_H 1
#pragma GCC system_header
#include <bits/c++config.h>
//
// This file provides some compile-time information about various types.
// These representations were designed, on purpose, to be constant-expressions
// and not types as found in <bits/type_traits.h>. In particular, they
// can be used in control structures and the optimizer hopefully will do
// the obvious thing.
//
// Why integral expressions, and not functions nor types?
// Firstly, these compile-time entities are used as template-arguments
// so function return values won't work: We need compile-time entities.
// We're left with types and constant integral expressions.
// Secondly, from the point of view of ease of use, type-based compile-time
// information is -not- *that* convenient. On has to write lots of
// overloaded functions and to hope that the compiler will select the right
// one. As a net effect, the overall structure isn't very clear at first
// glance.
// Thirdly, partial ordering and overload resolution (of function templates)
// is highly costly in terms of compiler-resource. It is a Good Thing to
// keep these resource consumption as least as possible.
//
// See valarray_array.h for a case use.
//
// -- Gaby (dosreis@cmla.ens-cachan.fr) 2000-03-06.
//
// Update 2005: types are also provided and <bits/type_traits.h> has been
// removed.
//
extern "C++" {
namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION
struct __true_type { };
struct __false_type { };
template<bool>
struct __truth_type
{ typedef __false_type __type; };
template<>
struct __truth_type<true>
{ typedef __true_type __type; };
// N.B. The conversions to bool are needed due to the issue
// explained in c++/19404.
template<class _Sp, class _Tp>
struct __traitor
{
enum { __value = bool(_Sp::__value) || bool(_Tp::__value) };
typedef typename __truth_type<__value>::__type __type;
};
// Compare for equality of types.
template<typename, typename>
struct __are_same
{
enum { __value = 0 };
typedef __false_type __type;
};
template<typename _Tp>
struct __are_same<_Tp, _Tp>
{
enum { __value = 1 };
typedef __true_type __type;
};
// Holds if the template-argument is a void type.
template<typename _Tp>
struct __is_void
{
enum { __value = 0 };
typedef __false_type __type;
};
template<>
struct __is_void<void>
{
enum { __value = 1 };
typedef __true_type __type;
};
//
// Integer types
//
template<typename _Tp>
struct __is_integer
{
enum { __value = 0 };
typedef __false_type __type;
};
// Thirteen specializations (yes there are eleven standard integer
// types; <em>long long</em> and <em>unsigned long long</em> are
// supported as extensions). Up to four target-specific __int<N>
// types are supported as well.
template<>
struct __is_integer<bool>
{
enum { __value = 1 };
typedef __true_type __type;
};
template<>
struct __is_integer<char>
{
enum { __value = 1 };
typedef __true_type __type;
};
template<>
struct __is_integer<signed char>
{
enum { __value = 1 };
typedef __true_type __type;
};
template<>
struct __is_integer<unsigned char>
{
enum { __value = 1 };
typedef __true_type __type;
};
# ifdef _GLIBCXX_USE_WCHAR_T
template<>
struct __is_integer<wchar_t>
{
enum { __value = 1 };
typedef __true_type __type;
};
# endif
#if __cplusplus >= 201103L
template<>
struct __is_integer<char16_t>
{
enum { __value = 1 };
typedef __true_type __type;
};
template<>
struct __is_integer<char32_t>
{
enum { __value = 1 };
typedef __true_type __type;
};
#endif
template<>
struct __is_integer<short>
{
enum { __value = 1 };
typedef __true_type __type;
};
template<>
struct __is_integer<unsigned short>
{
enum { __value = 1 };
typedef __true_type __type;
};
template<>
struct __is_integer<int>
{
enum { __value = 1 };
typedef __true_type __type;
};
template<>
struct __is_integer<unsigned int>
{
enum { __value = 1 };
typedef __true_type __type;
};
template<>
struct __is_integer<long>
{
enum { __value = 1 };
typedef __true_type __type;
};
template<>
struct __is_integer<unsigned long>
{
enum { __value = 1 };
typedef __true_type __type;
};
template<>
struct __is_integer<long long>
{
enum { __value = 1 };
typedef __true_type __type;
};
template<>
struct __is_integer<unsigned long long>
{
enum { __value = 1 };
typedef __true_type __type;
};
#define __INT_N(TYPE) \
template<> \
struct __is_integer<TYPE> \
{ \
enum { __value = 1 }; \
typedef __true_type __type; \
}; \
template<> \
struct __is_integer<unsigned TYPE> \
{ \
enum { __value = 1 }; \
typedef __true_type __type; \
};
#ifdef __GLIBCXX_TYPE_INT_N_0
__INT_N(__GLIBCXX_TYPE_INT_N_0)
#endif
#ifdef __GLIBCXX_TYPE_INT_N_1
__INT_N(__GLIBCXX_TYPE_INT_N_1)
#endif
#ifdef __GLIBCXX_TYPE_INT_N_2
__INT_N(__GLIBCXX_TYPE_INT_N_2)
#endif
#ifdef __GLIBCXX_TYPE_INT_N_3
__INT_N(__GLIBCXX_TYPE_INT_N_3)
#endif
#undef __INT_N
//
// Floating point types
//
template<typename _Tp>
struct __is_floating
{
enum { __value = 0 };
typedef __false_type __type;
};
// three specializations (float, double and 'long double')
template<>
struct __is_floating<float>
{
enum { __value = 1 };
typedef __true_type __type;
};
template<>
struct __is_floating<double>
{
enum { __value = 1 };
typedef __true_type __type;
};
template<>
struct __is_floating<long double>
{
enum { __value = 1 };
typedef __true_type __type;
};
//
// Pointer types
//
template<typename _Tp>
struct __is_pointer
{
enum { __value = 0 };
typedef __false_type __type;
};
template<typename _Tp>
struct __is_pointer<_Tp*>
{
enum { __value = 1 };
typedef __true_type __type;
};
//
// An arithmetic type is an integer type or a floating point type
//
template<typename _Tp>
struct __is_arithmetic
: public __traitor<__is_integer<_Tp>, __is_floating<_Tp> >
{ };
//
// A scalar type is an arithmetic type or a pointer type
//
template<typename _Tp>
struct __is_scalar
: public __traitor<__is_arithmetic<_Tp>, __is_pointer<_Tp> >
{ };
//
// For use in std::copy and std::find overloads for streambuf iterators.
//
template<typename _Tp>
struct __is_char
{
enum { __value = 0 };
typedef __false_type __type;
};
template<>
struct __is_char<char>
{
enum { __value = 1 };
typedef __true_type __type;
};
#ifdef _GLIBCXX_USE_WCHAR_T
template<>
struct __is_char<wchar_t>
{
enum { __value = 1 };
typedef __true_type __type;
};
#endif
template<typename _Tp>
struct __is_byte
{
enum { __value = 0 };
typedef __false_type __type;
};
template<>
struct __is_byte<char>
{
enum { __value = 1 };
typedef __true_type __type;
};
template<>
struct __is_byte<signed char>
{
enum { __value = 1 };
typedef __true_type __type;
};
template<>
struct __is_byte<unsigned char>
{
enum { __value = 1 };
typedef __true_type __type;
};
//
// Move iterator type
//
template<typename _Tp>
struct __is_move_iterator
{
enum { __value = 0 };
typedef __false_type __type;
};
// Fallback implementation of the function in bits/stl_iterator.h used to
// remove the move_iterator wrapper.
template<typename _Iterator>
inline _Iterator
__miter_base(_Iterator __it)
{ return __it; }
_GLIBCXX_END_NAMESPACE_VERSION
} // namespace
} // extern "C++"
#endif //_CPP_TYPE_TRAITS_H
|