]>
Commit | Line | Data |
---|---|---|
725dc051 BK |
1 | // The -*- C++ -*- type traits classes for internal use in libstdc++ |
2 | ||
cdc958d8 | 3 | // Copyright (C) 2000, 2001, 2002, 2003 Free Software Foundation, Inc. |
725dc051 BK |
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 | |
7 | // terms of the GNU General Public License as published by the | |
8 | // Free Software Foundation; either version 2, or (at your option) | |
9 | // any later version. | |
10 | ||
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. | |
15 | ||
16 | // You should have received a copy of the GNU General Public License along | |
17 | // with this library; see the file COPYING. If not, write to the Free | |
18 | // Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, | |
19 | // USA. | |
20 | ||
21 | // As a special exception, you may use this file as part of a free software | |
22 | // library without restriction. Specifically, if other files instantiate | |
23 | // templates or use macros or inline functions from this file, or you compile | |
24 | // this file and link it with other files to produce an executable, this | |
25 | // file does not by itself cause the resulting executable to be covered by | |
26 | // the GNU General Public License. This exception does not however | |
27 | // invalidate any other reasons why the executable file might be covered by | |
28 | // the GNU General Public License. | |
29 | ||
30 | // Written by Gabriel Dos Reis <dosreis@cmla.ens-cachan.fr> | |
31 | ||
729e3d3f PE |
32 | /** @file cpp_type_traits.h |
33 | * This is an internal header file, included by other library headers. | |
34 | * You should not attempt to use it directly. | |
35 | */ | |
36 | ||
3d7c150e BK |
37 | #ifndef _CPP_TYPE_TRAITS_H |
38 | #define _CPP_TYPE_TRAITS_H 1 | |
725dc051 | 39 | |
b0a85b86 GDR |
40 | #pragma GCC system_header |
41 | ||
725dc051 BK |
42 | // |
43 | // This file provides some compile-time information about various types. | |
ca6c4418 | 44 | // These representations were designed, on purpose, to be constant-expressions |
725dc051 BK |
45 | // and not types as found in <stl/bits/type_traits.h>. In particular, they |
46 | // can be used in control structures and the optimizer hopefully will do | |
47 | // the obvious thing. | |
48 | // | |
49 | // Why integral expressions, and not functions nor types? | |
ca6c4418 GDR |
50 | // Firstly, these compile-time entities are used as template-arguments |
51 | // so function return values won't work: We need compile-time entities. | |
52 | // We're left with types and constant integral expressions. | |
53 | // Secondly, from the point of view of ease of use, type-based compile-time | |
725dc051 BK |
54 | // information is -not- *that* convenient. On has to write lots of |
55 | // overloaded functions and to hope that the compiler will select the right | |
56 | // one. As a net effect, the overall structure isn't very clear at first | |
57 | // glance. | |
ca6c4418 GDR |
58 | // Thirdly, partial ordering and overload resolution (of function templates) |
59 | // is highly costly in terms of compiler-resource. It is a Good Thing to | |
725dc051 BK |
60 | // keep these resource consumption as least as possible. |
61 | // | |
ca6c4418 GDR |
62 | // See valarray_array.h for a case use. |
63 | // | |
725dc051 BK |
64 | // -- Gaby (dosreis@cmla.ens-cachan.fr) 2000-03-06. |
65 | // | |
66 | ||
ca6c4418 GDR |
67 | namespace std |
68 | { | |
cdc958d8 GDR |
69 | // Compare for equality of types. |
70 | template<typename, typename> | |
71 | struct __are_same | |
72 | { | |
73 | enum | |
74 | { | |
75 | _M_type = 0 | |
76 | }; | |
77 | }; | |
78 | ||
79 | template<typename _Tp> | |
80 | struct __are_same<_Tp, _Tp> | |
81 | { | |
82 | enum | |
83 | { | |
84 | _M_type = 1 | |
85 | }; | |
86 | }; | |
87 | ||
88 | // Define a nested type if some predicate holds. | |
89 | template<typename, bool> | |
90 | struct __enable_if | |
91 | { | |
92 | }; | |
93 | ||
94 | template<typename _Tp> | |
95 | struct __enable_if<_Tp, true> | |
96 | { | |
97 | typedef _Tp _M_type; | |
98 | }; | |
99 | ||
100 | // Holds if the template-argument is a void type. | |
725dc051 | 101 | template<typename _Tp> |
ca6c4418 | 102 | struct __is_void |
725dc051 | 103 | { |
ca6c4418 GDR |
104 | enum |
105 | { | |
106 | _M_type = 0 | |
107 | }; | |
725dc051 | 108 | }; |
725dc051 BK |
109 | |
110 | template<> | |
ca6c4418 | 111 | struct __is_void<void> |
725dc051 | 112 | { |
ca6c4418 GDR |
113 | enum |
114 | { | |
115 | _M_type = 1 | |
116 | }; | |
725dc051 | 117 | }; |
725dc051 BK |
118 | |
119 | // | |
120 | // Integer types | |
121 | // | |
122 | template<typename _Tp> | |
123 | struct __is_integer | |
124 | { | |
125 | enum | |
126 | { | |
127 | _M_type = 0 | |
128 | }; | |
129 | }; | |
130 | ||
131 | // Thirteen specializations (yes there are eleven standard integer | |
132 | // types; 'long long' and 'unsigned long long' are supported as | |
133 | // extensions) | |
134 | template<> | |
135 | struct __is_integer<bool> | |
136 | { | |
137 | enum | |
138 | { | |
139 | _M_type = 1 | |
140 | }; | |
141 | }; | |
142 | ||
143 | template<> | |
144 | struct __is_integer<char> | |
145 | { | |
146 | enum | |
147 | { | |
148 | _M_type = 1 | |
149 | }; | |
150 | }; | |
151 | ||
152 | template<> | |
153 | struct __is_integer<signed char> | |
154 | { | |
155 | enum | |
156 | { | |
157 | _M_type = 1 | |
158 | }; | |
159 | }; | |
160 | ||
161 | template<> | |
162 | struct __is_integer<unsigned char> | |
163 | { | |
164 | enum | |
165 | { | |
166 | _M_type = 1 | |
167 | }; | |
168 | }; | |
169 | ||
3d7c150e | 170 | # ifdef _GLIBCXX_USE_WCHAR_T |
725dc051 BK |
171 | template<> |
172 | struct __is_integer<wchar_t> | |
173 | { | |
174 | enum | |
175 | { | |
176 | _M_type = 1 | |
177 | }; | |
178 | }; | |
179 | # endif | |
180 | ||
181 | template<> | |
182 | struct __is_integer<short> | |
183 | { | |
184 | enum | |
185 | { | |
186 | _M_type = 1 | |
187 | }; | |
188 | }; | |
189 | ||
190 | template<> | |
191 | struct __is_integer<unsigned short> | |
192 | { | |
193 | enum | |
194 | { | |
195 | _M_type = 1 | |
196 | }; | |
197 | }; | |
198 | ||
199 | template<> | |
200 | struct __is_integer<int> | |
201 | { | |
202 | enum | |
203 | { | |
204 | _M_type = 1 | |
205 | }; | |
206 | }; | |
207 | ||
208 | template<> | |
209 | struct __is_integer<unsigned int> | |
210 | { | |
211 | enum | |
212 | { | |
213 | _M_type = 1 | |
214 | }; | |
215 | }; | |
216 | ||
217 | template<> | |
218 | struct __is_integer<long> | |
219 | { | |
220 | enum | |
221 | { | |
222 | _M_type = 1 | |
223 | }; | |
224 | }; | |
225 | ||
226 | template<> | |
227 | struct __is_integer<unsigned long> | |
228 | { | |
229 | enum | |
230 | { | |
231 | _M_type = 1 | |
232 | }; | |
233 | }; | |
234 | ||
725dc051 BK |
235 | template<> |
236 | struct __is_integer<long long> | |
237 | { | |
238 | enum | |
239 | { | |
240 | _M_type = 1 | |
241 | }; | |
242 | }; | |
243 | ||
244 | template<> | |
245 | struct __is_integer<unsigned long long> | |
246 | { | |
247 | enum | |
248 | { | |
249 | _M_type = 1 | |
250 | }; | |
251 | }; | |
725dc051 BK |
252 | |
253 | // | |
254 | // Floating point types | |
255 | // | |
256 | template<typename _Tp> | |
257 | struct __is_floating | |
258 | { | |
259 | enum | |
260 | { | |
261 | _M_type = 0 | |
262 | }; | |
263 | }; | |
264 | ||
265 | // three specializations (float, double and 'long double') | |
266 | template<> | |
267 | struct __is_floating<float> | |
268 | { | |
269 | enum | |
270 | { | |
271 | _M_type = 1 | |
272 | }; | |
273 | }; | |
274 | ||
275 | template<> | |
276 | struct __is_floating<double> | |
277 | { | |
278 | enum | |
279 | { | |
280 | _M_type = 1 | |
281 | }; | |
282 | }; | |
283 | ||
284 | template<> | |
285 | struct __is_floating<long double> | |
286 | { | |
287 | enum | |
288 | { | |
289 | _M_type = 1 | |
290 | }; | |
291 | }; | |
292 | ||
293 | // | |
294 | // An arithmetic type is an integer type or a floating point type | |
295 | // | |
296 | template<typename _Tp> | |
297 | struct __is_arithmetic | |
298 | { | |
299 | enum | |
300 | { | |
301 | _M_type = __is_integer<_Tp>::_M_type || __is_floating<_Tp>::_M_type | |
302 | }; | |
303 | }; | |
304 | ||
305 | // | |
306 | // A fundamental type is `void' or and arithmetic type | |
307 | // | |
308 | template<typename _Tp> | |
309 | struct __is_fundamental | |
310 | { | |
311 | enum | |
312 | { | |
313 | _M_type = __is_void<_Tp>::_M_type || __is_arithmetic<_Tp>::_M_type | |
314 | }; | |
315 | }; | |
316 | ||
317 | // | |
318 | // For the immediate use, the following is a good approximation | |
319 | // | |
320 | template<typename _Tp> | |
321 | struct __is_pod | |
322 | { | |
323 | enum | |
324 | { | |
325 | _M_type = __is_fundamental<_Tp>::_M_type | |
326 | }; | |
327 | }; | |
328 | ||
329 | } // namespace std | |
330 | ||
331 | ||
3d7c150e | 332 | #endif //_CPP_TYPE_TRAITS_H |