1 // TR1 type_traits -*- C++ -*-
3 // Copyright (C) 2007, 2008, 2009 Free Software Foundation, Inc.
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
7 // terms of the GNU General Public License as published by the
8 // Free Software Foundation; either version 3, or (at your option)
11 // This library is distributed in the hope that it will be useful,
12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 // GNU General Public License for more details.
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.
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/>.
25 /** @file tr1_impl/type_traits
26 * This is an internal header file, included by other library headers.
27 * You should not attempt to use it directly.
32 _GLIBCXX_BEGIN_NAMESPACE_TR1
35 * @defgroup metaprogramming Type Traits
38 * Compile time type transformation and information.
42 // For use in __is_convertible_simple.
46 typedef struct { char __arr[2]; } __two;
49 #define _DEFINE_SPEC_0_HELPER \
52 #define _DEFINE_SPEC_1_HELPER \
53 template<typename _Tp>
55 #define _DEFINE_SPEC_2_HELPER \
56 template<typename _Tp, typename _Cp>
58 #define _DEFINE_SPEC(_Order, _Trait, _Type, _Value) \
59 _DEFINE_SPEC_##_Order##_HELPER \
60 struct _Trait<_Type> \
61 : public integral_constant<bool, _Value> { };
63 // helper classes [4.3].
66 template<typename _Tp, _Tp __v>
67 struct integral_constant
69 static const _Tp value = __v;
70 typedef _Tp value_type;
71 typedef integral_constant<_Tp, __v> type;
74 /// typedef for true_type
75 typedef integral_constant<bool, true> true_type;
77 /// typedef for false_type
78 typedef integral_constant<bool, false> false_type;
80 template<typename _Tp, _Tp __v>
81 const _Tp integral_constant<_Tp, __v>::value;
88 struct __is_void_helper
89 : public false_type { };
90 _DEFINE_SPEC(0, __is_void_helper, void, true)
92 // primary type categories [4.5.1].
95 template<typename _Tp>
97 : public integral_constant<bool, (__is_void_helper<typename
98 remove_cv<_Tp>::type>::value)>
102 struct __is_integral_helper
103 : public false_type { };
104 _DEFINE_SPEC(0, __is_integral_helper, bool, true)
105 _DEFINE_SPEC(0, __is_integral_helper, char, true)
106 _DEFINE_SPEC(0, __is_integral_helper, signed char, true)
107 _DEFINE_SPEC(0, __is_integral_helper, unsigned char, true)
108 #ifdef _GLIBCXX_USE_WCHAR_T
109 _DEFINE_SPEC(0, __is_integral_helper, wchar_t, true)
111 #ifdef _GLIBCXX_INCLUDE_AS_CXX0X
112 _DEFINE_SPEC(0, __is_integral_helper, char16_t, true)
113 _DEFINE_SPEC(0, __is_integral_helper, char32_t, true)
115 _DEFINE_SPEC(0, __is_integral_helper, short, true)
116 _DEFINE_SPEC(0, __is_integral_helper, unsigned short, true)
117 _DEFINE_SPEC(0, __is_integral_helper, int, true)
118 _DEFINE_SPEC(0, __is_integral_helper, unsigned int, true)
119 _DEFINE_SPEC(0, __is_integral_helper, long, true)
120 _DEFINE_SPEC(0, __is_integral_helper, unsigned long, true)
121 _DEFINE_SPEC(0, __is_integral_helper, long long, true)
122 _DEFINE_SPEC(0, __is_integral_helper, unsigned long long, true)
125 template<typename _Tp>
127 : public integral_constant<bool, (__is_integral_helper<typename
128 remove_cv<_Tp>::type>::value)>
132 struct __is_floating_point_helper
133 : public false_type { };
134 _DEFINE_SPEC(0, __is_floating_point_helper, float, true)
135 _DEFINE_SPEC(0, __is_floating_point_helper, double, true)
136 _DEFINE_SPEC(0, __is_floating_point_helper, long double, true)
138 /// is_floating_point
139 template<typename _Tp>
140 struct is_floating_point
141 : public integral_constant<bool, (__is_floating_point_helper<typename
142 remove_cv<_Tp>::type>::value)>
148 : public false_type { };
150 template<typename _Tp, std::size_t _Size>
151 struct is_array<_Tp[_Size]>
152 : public true_type { };
154 template<typename _Tp>
155 struct is_array<_Tp[]>
156 : public true_type { };
159 struct __is_pointer_helper
160 : public false_type { };
161 _DEFINE_SPEC(1, __is_pointer_helper, _Tp*, true)
164 template<typename _Tp>
166 : public integral_constant<bool, (__is_pointer_helper<typename
167 remove_cv<_Tp>::type>::value)>
171 template<typename _Tp>
175 template<typename _Tp>
179 struct __is_member_object_pointer_helper
180 : public false_type { };
181 _DEFINE_SPEC(2, __is_member_object_pointer_helper, _Tp _Cp::*,
182 !is_function<_Tp>::value)
184 /// is_member_object_pointer
185 template<typename _Tp>
186 struct is_member_object_pointer
187 : public integral_constant<bool, (__is_member_object_pointer_helper<
188 typename remove_cv<_Tp>::type>::value)>
192 struct __is_member_function_pointer_helper
193 : public false_type { };
194 _DEFINE_SPEC(2, __is_member_function_pointer_helper, _Tp _Cp::*,
195 is_function<_Tp>::value)
197 /// is_member_function_pointer
198 template<typename _Tp>
199 struct is_member_function_pointer
200 : public integral_constant<bool, (__is_member_function_pointer_helper<
201 typename remove_cv<_Tp>::type>::value)>
205 template<typename _Tp>
207 : public integral_constant<bool, __is_enum(_Tp)>
211 template<typename _Tp>
213 : public integral_constant<bool, __is_union(_Tp)>
217 template<typename _Tp>
219 : public integral_constant<bool, __is_class(_Tp)>
225 : public false_type { };
226 template<typename _Res, typename... _ArgTypes>
227 struct is_function<_Res(_ArgTypes...)>
228 : public true_type { };
229 template<typename _Res, typename... _ArgTypes>
230 struct is_function<_Res(_ArgTypes......)>
231 : public true_type { };
232 template<typename _Res, typename... _ArgTypes>
233 struct is_function<_Res(_ArgTypes...) const>
234 : public true_type { };
235 template<typename _Res, typename... _ArgTypes>
236 struct is_function<_Res(_ArgTypes......) const>
237 : public true_type { };
238 template<typename _Res, typename... _ArgTypes>
239 struct is_function<_Res(_ArgTypes...) volatile>
240 : public true_type { };
241 template<typename _Res, typename... _ArgTypes>
242 struct is_function<_Res(_ArgTypes......) volatile>
243 : public true_type { };
244 template<typename _Res, typename... _ArgTypes>
245 struct is_function<_Res(_ArgTypes...) const volatile>
246 : public true_type { };
247 template<typename _Res, typename... _ArgTypes>
248 struct is_function<_Res(_ArgTypes......) const volatile>
249 : public true_type { };
251 // composite type traits [4.5.2].
254 template<typename _Tp>
256 : public integral_constant<bool, (is_integral<_Tp>::value
257 || is_floating_point<_Tp>::value)>
261 template<typename _Tp>
262 struct is_fundamental
263 : public integral_constant<bool, (is_arithmetic<_Tp>::value
264 || is_void<_Tp>::value)>
268 template<typename _Tp>
270 : public integral_constant<bool, !(is_function<_Tp>::value
271 || is_reference<_Tp>::value
272 || is_void<_Tp>::value)>
275 /// is_member_pointer
276 template<typename _Tp>
277 struct is_member_pointer;
280 template<typename _Tp>
282 : public integral_constant<bool, (is_arithmetic<_Tp>::value
283 || is_enum<_Tp>::value
284 || is_pointer<_Tp>::value
285 || is_member_pointer<_Tp>::value)>
289 template<typename _Tp>
291 : public integral_constant<bool, !is_fundamental<_Tp>::value> { };
293 /// is_member_pointer
294 template<typename _Tp>
295 struct __is_member_pointer_helper
296 : public false_type { };
297 _DEFINE_SPEC(2, __is_member_pointer_helper, _Tp _Cp::*, true)
299 template<typename _Tp>
300 struct is_member_pointer
301 : public integral_constant<bool, (__is_member_pointer_helper<
302 typename remove_cv<_Tp>::type>::value)>
305 // type properties [4.5.3].
309 : public false_type { };
311 template<typename _Tp>
312 struct is_const<_Tp const>
313 : public true_type { };
318 : public false_type { };
320 template<typename _Tp>
321 struct is_volatile<_Tp volatile>
322 : public true_type { };
325 template<typename _Tp>
327 : public integral_constant<bool, __is_empty(_Tp)>
331 template<typename _Tp>
332 struct is_polymorphic
333 : public integral_constant<bool, __is_polymorphic(_Tp)>
337 template<typename _Tp>
339 : public integral_constant<bool, __is_abstract(_Tp)>
342 /// has_virtual_destructor
343 template<typename _Tp>
344 struct has_virtual_destructor
345 : public integral_constant<bool, __has_virtual_destructor(_Tp)>
349 template<typename _Tp>
351 : public integral_constant<std::size_t, __alignof__(_Tp)> { };
356 : public integral_constant<std::size_t, 0> { };
358 template<typename _Tp, std::size_t _Size>
359 struct rank<_Tp[_Size]>
360 : public integral_constant<std::size_t, 1 + rank<_Tp>::value> { };
362 template<typename _Tp>
364 : public integral_constant<std::size_t, 1 + rank<_Tp>::value> { };
367 template<typename, unsigned _Uint = 0>
369 : public integral_constant<std::size_t, 0> { };
371 template<typename _Tp, unsigned _Uint, std::size_t _Size>
372 struct extent<_Tp[_Size], _Uint>
373 : public integral_constant<std::size_t,
374 _Uint == 0 ? _Size : extent<_Tp,
378 template<typename _Tp, unsigned _Uint>
379 struct extent<_Tp[], _Uint>
380 : public integral_constant<std::size_t,
381 _Uint == 0 ? 0 : extent<_Tp,
385 // relationships between types [4.6].
388 template<typename, typename>
390 : public false_type { };
392 template<typename _Tp>
393 struct is_same<_Tp, _Tp>
394 : public true_type { };
396 // const-volatile modifications [4.7.1].
399 template<typename _Tp>
401 { typedef _Tp type; };
403 template<typename _Tp>
404 struct remove_const<_Tp const>
405 { typedef _Tp type; };
408 template<typename _Tp>
409 struct remove_volatile
410 { typedef _Tp type; };
412 template<typename _Tp>
413 struct remove_volatile<_Tp volatile>
414 { typedef _Tp type; };
417 template<typename _Tp>
421 remove_const<typename remove_volatile<_Tp>::type>::type type;
425 template<typename _Tp>
427 { typedef _Tp const type; };
430 template<typename _Tp>
432 { typedef _Tp volatile type; };
435 template<typename _Tp>
439 add_const<typename add_volatile<_Tp>::type>::type type;
442 // array modifications [4.7.3].
445 template<typename _Tp>
447 { typedef _Tp type; };
449 template<typename _Tp, std::size_t _Size>
450 struct remove_extent<_Tp[_Size]>
451 { typedef _Tp type; };
453 template<typename _Tp>
454 struct remove_extent<_Tp[]>
455 { typedef _Tp type; };
457 /// remove_all_extents
458 template<typename _Tp>
459 struct remove_all_extents
460 { typedef _Tp type; };
462 template<typename _Tp, std::size_t _Size>
463 struct remove_all_extents<_Tp[_Size]>
464 { typedef typename remove_all_extents<_Tp>::type type; };
466 template<typename _Tp>
467 struct remove_all_extents<_Tp[]>
468 { typedef typename remove_all_extents<_Tp>::type type; };
470 // pointer modifications [4.7.4].
472 template<typename _Tp, typename>
473 struct __remove_pointer_helper
474 { typedef _Tp type; };
476 template<typename _Tp, typename _Up>
477 struct __remove_pointer_helper<_Tp, _Up*>
478 { typedef _Up type; };
481 template<typename _Tp>
482 struct remove_pointer
483 : public __remove_pointer_helper<_Tp, typename remove_cv<_Tp>::type>
487 struct remove_reference;
490 template<typename _Tp>
492 { typedef typename remove_reference<_Tp>::type* type; };
494 #undef _DEFINE_SPEC_0_HELPER
495 #undef _DEFINE_SPEC_1_HELPER
496 #undef _DEFINE_SPEC_2_HELPER
499 // @} group metaprogramming
500 _GLIBCXX_END_NAMESPACE_TR1