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1 | // The -*- C++ -*- type traits classes for internal use in libstdc++ |
2 | ||
2a60a9f6 | 3 | // Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2009, 2010 |
c0736a9d | 4 | // Free Software Foundation, Inc. |
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5 | // |
6 | // This file is part of the GNU ISO C++ Library. This library is free | |
7 | // software; you can redistribute it and/or modify it under the | |
8 | // terms of the GNU General Public License as published by the | |
748086b7 | 9 | // Free Software Foundation; either version 3, or (at your option) |
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10 | // any later version. |
11 | ||
12 | // This library is distributed in the hope that it will be useful, | |
13 | // but WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
15 | // GNU General Public License for more details. | |
16 | ||
748086b7 JJ |
17 | // Under Section 7 of GPL version 3, you are granted additional |
18 | // permissions described in the GCC Runtime Library Exception, version | |
19 | // 3.1, as published by the Free Software Foundation. | |
20 | ||
21 | // You should have received a copy of the GNU General Public License and | |
22 | // a copy of the GCC Runtime Library Exception along with this program; | |
23 | // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see | |
24 | // <http://www.gnu.org/licenses/>. | |
725dc051 | 25 | |
f910786b | 26 | /** @file bits/cpp_type_traits.h |
729e3d3f | 27 | * This is an internal header file, included by other library headers. |
f910786b | 28 | * Do not attempt to use it directly. @headername{ext/type_traits} |
729e3d3f PE |
29 | */ |
30 | ||
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31 | // Written by Gabriel Dos Reis <dosreis@cmla.ens-cachan.fr> |
32 | ||
3d7c150e BK |
33 | #ifndef _CPP_TYPE_TRAITS_H |
34 | #define _CPP_TYPE_TRAITS_H 1 | |
725dc051 | 35 | |
b0a85b86 GDR |
36 | #pragma GCC system_header |
37 | ||
c0736a9d PC |
38 | #include <bits/c++config.h> |
39 | ||
725dc051 BK |
40 | // |
41 | // This file provides some compile-time information about various types. | |
ca6c4418 | 42 | // These representations were designed, on purpose, to be constant-expressions |
5e91e92e | 43 | // and not types as found in <bits/type_traits.h>. In particular, they |
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44 | // can be used in control structures and the optimizer hopefully will do |
45 | // the obvious thing. | |
46 | // | |
47 | // Why integral expressions, and not functions nor types? | |
ca6c4418 GDR |
48 | // Firstly, these compile-time entities are used as template-arguments |
49 | // so function return values won't work: We need compile-time entities. | |
50 | // We're left with types and constant integral expressions. | |
51 | // Secondly, from the point of view of ease of use, type-based compile-time | |
725dc051 BK |
52 | // information is -not- *that* convenient. On has to write lots of |
53 | // overloaded functions and to hope that the compiler will select the right | |
54 | // one. As a net effect, the overall structure isn't very clear at first | |
55 | // glance. | |
ca6c4418 GDR |
56 | // Thirdly, partial ordering and overload resolution (of function templates) |
57 | // is highly costly in terms of compiler-resource. It is a Good Thing to | |
725dc051 BK |
58 | // keep these resource consumption as least as possible. |
59 | // | |
ca6c4418 GDR |
60 | // See valarray_array.h for a case use. |
61 | // | |
725dc051 BK |
62 | // -- Gaby (dosreis@cmla.ens-cachan.fr) 2000-03-06. |
63 | // | |
c0736a9d PC |
64 | // Update 2005: types are also provided and <bits/type_traits.h> has been |
65 | // removed. | |
66 | // | |
725dc051 | 67 | |
5e91e92e | 68 | // Forward declaration hack, should really include this from somewhere. |
3cbc7af0 BK |
69 | _GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx) |
70 | ||
5e91e92e PC |
71 | template<typename _Iterator, typename _Container> |
72 | class __normal_iterator; | |
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73 | |
74 | _GLIBCXX_END_NAMESPACE | |
5e91e92e | 75 | |
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76 | _GLIBCXX_BEGIN_NAMESPACE(std) |
77 | ||
78a53887 BK |
78 | struct __true_type { }; |
79 | struct __false_type { }; | |
80 | ||
c0736a9d PC |
81 | template<bool> |
82 | struct __truth_type | |
83 | { typedef __false_type __type; }; | |
84 | ||
85 | template<> | |
86 | struct __truth_type<true> | |
87 | { typedef __true_type __type; }; | |
88 | ||
a9dd5a46 PC |
89 | // N.B. The conversions to bool are needed due to the issue |
90 | // explained in c++/19404. | |
c0736a9d PC |
91 | template<class _Sp, class _Tp> |
92 | struct __traitor | |
93 | { | |
a9dd5a46 | 94 | enum { __value = bool(_Sp::__value) || bool(_Tp::__value) }; |
4d73fac9 | 95 | typedef typename __truth_type<__value>::__type __type; |
c0736a9d PC |
96 | }; |
97 | ||
cdc958d8 GDR |
98 | // Compare for equality of types. |
99 | template<typename, typename> | |
100 | struct __are_same | |
101 | { | |
4d73fac9 PC |
102 | enum { __value = 0 }; |
103 | typedef __false_type __type; | |
cdc958d8 GDR |
104 | }; |
105 | ||
106 | template<typename _Tp> | |
107 | struct __are_same<_Tp, _Tp> | |
108 | { | |
4d73fac9 PC |
109 | enum { __value = 1 }; |
110 | typedef __true_type __type; | |
cdc958d8 GDR |
111 | }; |
112 | ||
cdc958d8 | 113 | // Holds if the template-argument is a void type. |
725dc051 | 114 | template<typename _Tp> |
ca6c4418 | 115 | struct __is_void |
725dc051 | 116 | { |
4d73fac9 | 117 | enum { __value = 0 }; |
c0736a9d | 118 | typedef __false_type __type; |
725dc051 | 119 | }; |
725dc051 BK |
120 | |
121 | template<> | |
ca6c4418 | 122 | struct __is_void<void> |
725dc051 | 123 | { |
4d73fac9 | 124 | enum { __value = 1 }; |
c0736a9d | 125 | typedef __true_type __type; |
725dc051 | 126 | }; |
725dc051 BK |
127 | |
128 | // | |
129 | // Integer types | |
130 | // | |
131 | template<typename _Tp> | |
132 | struct __is_integer | |
133 | { | |
4d73fac9 | 134 | enum { __value = 0 }; |
c0736a9d | 135 | typedef __false_type __type; |
725dc051 BK |
136 | }; |
137 | ||
138 | // Thirteen specializations (yes there are eleven standard integer | |
2a60a9f6 BK |
139 | // types; <em>long long</em> and <em>unsigned long long</em> are |
140 | // supported as extensions) | |
725dc051 BK |
141 | template<> |
142 | struct __is_integer<bool> | |
143 | { | |
4d73fac9 | 144 | enum { __value = 1 }; |
c0736a9d | 145 | typedef __true_type __type; |
725dc051 | 146 | }; |
ed6814f7 | 147 | |
725dc051 BK |
148 | template<> |
149 | struct __is_integer<char> | |
150 | { | |
4d73fac9 | 151 | enum { __value = 1 }; |
c0736a9d | 152 | typedef __true_type __type; |
725dc051 BK |
153 | }; |
154 | ||
155 | template<> | |
156 | struct __is_integer<signed char> | |
157 | { | |
4d73fac9 | 158 | enum { __value = 1 }; |
c0736a9d | 159 | typedef __true_type __type; |
725dc051 | 160 | }; |
ed6814f7 | 161 | |
725dc051 | 162 | template<> |
ff89096a | 163 | struct __is_integer<unsigned char> |
725dc051 | 164 | { |
4d73fac9 | 165 | enum { __value = 1 }; |
c0736a9d | 166 | typedef __true_type __type; |
725dc051 | 167 | }; |
725dc051 | 168 | |
3d7c150e | 169 | # ifdef _GLIBCXX_USE_WCHAR_T |
725dc051 | 170 | template<> |
ff89096a | 171 | struct __is_integer<wchar_t> |
725dc051 | 172 | { |
4d73fac9 | 173 | enum { __value = 1 }; |
c0736a9d | 174 | typedef __true_type __type; |
725dc051 | 175 | }; |
725dc051 | 176 | # endif |
ed6814f7 | 177 | |
37f449aa PC |
178 | #ifdef __GXX_EXPERIMENTAL_CXX0X__ |
179 | template<> | |
180 | struct __is_integer<char16_t> | |
181 | { | |
182 | enum { __value = 1 }; | |
183 | typedef __true_type __type; | |
184 | }; | |
185 | ||
186 | template<> | |
187 | struct __is_integer<char32_t> | |
188 | { | |
189 | enum { __value = 1 }; | |
190 | typedef __true_type __type; | |
191 | }; | |
192 | #endif | |
193 | ||
725dc051 | 194 | template<> |
ff89096a | 195 | struct __is_integer<short> |
725dc051 | 196 | { |
4d73fac9 | 197 | enum { __value = 1 }; |
c0736a9d | 198 | typedef __true_type __type; |
725dc051 | 199 | }; |
725dc051 BK |
200 | |
201 | template<> | |
ff89096a | 202 | struct __is_integer<unsigned short> |
725dc051 | 203 | { |
4d73fac9 | 204 | enum { __value = 1 }; |
c0736a9d | 205 | typedef __true_type __type; |
725dc051 | 206 | }; |
725dc051 BK |
207 | |
208 | template<> | |
ff89096a | 209 | struct __is_integer<int> |
725dc051 | 210 | { |
4d73fac9 | 211 | enum { __value = 1 }; |
c0736a9d | 212 | typedef __true_type __type; |
725dc051 | 213 | }; |
725dc051 BK |
214 | |
215 | template<> | |
ff89096a | 216 | struct __is_integer<unsigned int> |
725dc051 | 217 | { |
4d73fac9 | 218 | enum { __value = 1 }; |
c0736a9d | 219 | typedef __true_type __type; |
725dc051 | 220 | }; |
725dc051 BK |
221 | |
222 | template<> | |
ff89096a | 223 | struct __is_integer<long> |
725dc051 | 224 | { |
4d73fac9 | 225 | enum { __value = 1 }; |
c0736a9d | 226 | typedef __true_type __type; |
725dc051 | 227 | }; |
725dc051 BK |
228 | |
229 | template<> | |
ff89096a | 230 | struct __is_integer<unsigned long> |
725dc051 | 231 | { |
4d73fac9 | 232 | enum { __value = 1 }; |
c0736a9d | 233 | typedef __true_type __type; |
725dc051 | 234 | }; |
725dc051 | 235 | |
725dc051 | 236 | template<> |
ff89096a | 237 | struct __is_integer<long long> |
725dc051 | 238 | { |
4d73fac9 | 239 | enum { __value = 1 }; |
c0736a9d | 240 | typedef __true_type __type; |
725dc051 | 241 | }; |
725dc051 BK |
242 | |
243 | template<> | |
ff89096a | 244 | struct __is_integer<unsigned long long> |
725dc051 | 245 | { |
4d73fac9 | 246 | enum { __value = 1 }; |
c0736a9d | 247 | typedef __true_type __type; |
725dc051 | 248 | }; |
725dc051 BK |
249 | |
250 | // | |
251 | // Floating point types | |
252 | // | |
253 | template<typename _Tp> | |
ff89096a | 254 | struct __is_floating |
725dc051 | 255 | { |
4d73fac9 | 256 | enum { __value = 0 }; |
c0736a9d | 257 | typedef __false_type __type; |
725dc051 | 258 | }; |
725dc051 BK |
259 | |
260 | // three specializations (float, double and 'long double') | |
261 | template<> | |
ff89096a | 262 | struct __is_floating<float> |
725dc051 | 263 | { |
4d73fac9 | 264 | enum { __value = 1 }; |
c0736a9d | 265 | typedef __true_type __type; |
725dc051 | 266 | }; |
725dc051 BK |
267 | |
268 | template<> | |
ff89096a | 269 | struct __is_floating<double> |
725dc051 | 270 | { |
4d73fac9 | 271 | enum { __value = 1 }; |
c0736a9d | 272 | typedef __true_type __type; |
725dc051 | 273 | }; |
725dc051 BK |
274 | |
275 | template<> | |
ff89096a | 276 | struct __is_floating<long double> |
725dc051 | 277 | { |
4d73fac9 | 278 | enum { __value = 1 }; |
c0736a9d | 279 | typedef __true_type __type; |
725dc051 | 280 | }; |
725dc051 | 281 | |
badd64ad PC |
282 | // |
283 | // Pointer types | |
284 | // | |
285 | template<typename _Tp> | |
286 | struct __is_pointer | |
287 | { | |
4d73fac9 | 288 | enum { __value = 0 }; |
c0736a9d | 289 | typedef __false_type __type; |
badd64ad PC |
290 | }; |
291 | ||
292 | template<typename _Tp> | |
293 | struct __is_pointer<_Tp*> | |
294 | { | |
4d73fac9 | 295 | enum { __value = 1 }; |
c0736a9d | 296 | typedef __true_type __type; |
5e91e92e PC |
297 | }; |
298 | ||
299 | // | |
300 | // Normal iterator type | |
301 | // | |
302 | template<typename _Tp> | |
303 | struct __is_normal_iterator | |
304 | { | |
4d73fac9 | 305 | enum { __value = 0 }; |
c0736a9d | 306 | typedef __false_type __type; |
5e91e92e PC |
307 | }; |
308 | ||
309 | template<typename _Iterator, typename _Container> | |
310 | struct __is_normal_iterator< __gnu_cxx::__normal_iterator<_Iterator, | |
311 | _Container> > | |
312 | { | |
4d73fac9 | 313 | enum { __value = 1 }; |
c0736a9d | 314 | typedef __true_type __type; |
badd64ad PC |
315 | }; |
316 | ||
725dc051 BK |
317 | // |
318 | // An arithmetic type is an integer type or a floating point type | |
319 | // | |
320 | template<typename _Tp> | |
ff89096a | 321 | struct __is_arithmetic |
c0736a9d PC |
322 | : public __traitor<__is_integer<_Tp>, __is_floating<_Tp> > |
323 | { }; | |
324 | ||
725dc051 BK |
325 | // |
326 | // A fundamental type is `void' or and arithmetic type | |
327 | // | |
328 | template<typename _Tp> | |
ff89096a | 329 | struct __is_fundamental |
c0736a9d PC |
330 | : public __traitor<__is_void<_Tp>, __is_arithmetic<_Tp> > |
331 | { }; | |
725dc051 | 332 | |
badd64ad | 333 | // |
67dd4a93 | 334 | // A scalar type is an arithmetic type or a pointer type |
badd64ad PC |
335 | // |
336 | template<typename _Tp> | |
67dd4a93 | 337 | struct __is_scalar |
c0736a9d PC |
338 | : public __traitor<__is_arithmetic<_Tp>, __is_pointer<_Tp> > |
339 | { }; | |
badd64ad | 340 | |
0002d5d2 PC |
341 | // |
342 | // For use in std::copy and std::find overloads for streambuf iterators. | |
343 | // | |
344 | template<typename _Tp> | |
345 | struct __is_char | |
346 | { | |
347 | enum { __value = 0 }; | |
348 | typedef __false_type __type; | |
349 | }; | |
350 | ||
351 | template<> | |
352 | struct __is_char<char> | |
353 | { | |
354 | enum { __value = 1 }; | |
355 | typedef __true_type __type; | |
356 | }; | |
357 | ||
358 | #ifdef _GLIBCXX_USE_WCHAR_T | |
359 | template<> | |
360 | struct __is_char<wchar_t> | |
361 | { | |
362 | enum { __value = 1 }; | |
363 | typedef __true_type __type; | |
364 | }; | |
365 | #endif | |
366 | ||
394033f8 PC |
367 | template<typename _Tp> |
368 | struct __is_byte | |
369 | { | |
370 | enum { __value = 0 }; | |
371 | typedef __false_type __type; | |
372 | }; | |
373 | ||
374 | template<> | |
375 | struct __is_byte<char> | |
376 | { | |
377 | enum { __value = 1 }; | |
378 | typedef __true_type __type; | |
379 | }; | |
380 | ||
381 | template<> | |
382 | struct __is_byte<signed char> | |
383 | { | |
384 | enum { __value = 1 }; | |
385 | typedef __true_type __type; | |
386 | }; | |
387 | ||
388 | template<> | |
389 | struct __is_byte<unsigned char> | |
390 | { | |
391 | enum { __value = 1 }; | |
392 | typedef __true_type __type; | |
393 | }; | |
394 | ||
f0112db9 PC |
395 | // |
396 | // Move iterator type | |
397 | // | |
398 | template<typename _Tp> | |
399 | struct __is_move_iterator | |
400 | { | |
401 | enum { __value = 0 }; | |
402 | typedef __false_type __type; | |
403 | }; | |
404 | ||
405 | #ifdef __GXX_EXPERIMENTAL_CXX0X__ | |
406 | template<typename _Iterator> | |
407 | class move_iterator; | |
408 | ||
409 | template<typename _Iterator> | |
410 | struct __is_move_iterator< move_iterator<_Iterator> > | |
411 | { | |
412 | enum { __value = 1 }; | |
413 | typedef __true_type __type; | |
414 | }; | |
415 | #endif | |
416 | ||
3cbc7af0 | 417 | _GLIBCXX_END_NAMESPACE |
725dc051 | 418 | |
3d7c150e | 419 | #endif //_CPP_TYPE_TRAITS_H |