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54c1bf78 | 1 | // <memory> -*- C++ -*- |
de96ac46 | 2 | |
917a9fd4 | 3 | // Copyright (C) 2001, 2002, 2004 Free Software Foundation, Inc. |
de96ac46 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 | ||
54c1bf78 BK |
30 | /* |
31 | * Copyright (c) 1997-1999 | |
32 | * Silicon Graphics Computer Systems, Inc. | |
33 | * | |
34 | * Permission to use, copy, modify, distribute and sell this software | |
35 | * and its documentation for any purpose is hereby granted without fee, | |
36 | * provided that the above copyright notice appear in all copies and | |
37 | * that both that copyright notice and this permission notice appear | |
38 | * in supporting documentation. Silicon Graphics makes no | |
39 | * representations about the suitability of this software for any | |
40 | * purpose. It is provided "as is" without express or implied warranty. | |
41 | * | |
42 | */ | |
43 | ||
20fff8cd | 44 | /** @file |
ffe94f83 PE |
45 | * This is a Standard C++ Library header. You should @c #include this header |
46 | * in your programs, rather than any of the "st[dl]_*.h" implementation files. | |
2f9d51b8 PE |
47 | */ |
48 | ||
1143680e SE |
49 | #ifndef _GLIBCXX_MEMORY |
50 | #define _GLIBCXX_MEMORY 1 | |
54c1bf78 BK |
51 | |
52 | #pragma GCC system_header | |
53 | ||
54 | #include <bits/stl_algobase.h> | |
1ff9402d | 55 | #include <bits/allocator.h> |
54c1bf78 BK |
56 | #include <bits/stl_construct.h> |
57 | #include <bits/stl_iterator_base_types.h> //for iterator_traits | |
54c1bf78 BK |
58 | #include <bits/stl_uninitialized.h> |
59 | #include <bits/stl_raw_storage_iter.h> | |
285b36d6 | 60 | #include <debug/debug.h> |
dafa8871 | 61 | #include <limits> |
54c1bf78 BK |
62 | |
63 | namespace std | |
64 | { | |
16ad69a1 | 65 | /** |
5acf59f8 BK |
66 | * @if maint |
67 | * This is a helper function. The unused second parameter exists to | |
68 | * permit the real get_temporary_buffer to use template parameter deduction. | |
16ad69a1 | 69 | * |
5acf59f8 BK |
70 | * XXX This should perhaps use the pool. |
71 | * @endif | |
72 | */ | |
73 | template<typename _Tp> | |
74 | pair<_Tp*, ptrdiff_t> | |
75 | __get_temporary_buffer(ptrdiff_t __len, _Tp*) | |
16ad69a1 | 76 | { |
dafa8871 PC |
77 | const ptrdiff_t __max = numeric_limits<ptrdiff_t>::max() / sizeof(_Tp); |
78 | if (__len > __max) | |
79 | __len = __max; | |
5acf59f8 BK |
80 | |
81 | while (__len > 0) | |
82 | { | |
917a9fd4 SW |
83 | _Tp* __tmp = static_cast<_Tp*>(::operator new(__len * sizeof(_Tp), |
84 | nothrow)); | |
5acf59f8 BK |
85 | if (__tmp != 0) |
86 | return pair<_Tp*, ptrdiff_t>(__tmp, __len); | |
87 | __len /= 2; | |
88 | } | |
917a9fd4 | 89 | return pair<_Tp*, ptrdiff_t>(static_cast<_Tp*>(0), 0); |
16ad69a1 JR |
90 | } |
91 | ||
92 | /** | |
917a9fd4 | 93 | * @brief Allocates a temporary buffer. |
5acf59f8 | 94 | * @param len The number of objects of type Tp. |
917a9fd4 | 95 | * @return See full description. |
16ad69a1 | 96 | * |
5acf59f8 | 97 | * Reinventing the wheel, but this time with prettier spokes! |
16ad69a1 | 98 | * |
917a9fd4 SW |
99 | * This function tries to obtain storage for @c len adjacent Tp |
100 | * objects. The objects themselves are not constructed, of course. | |
101 | * A pair<> is returned containing "the buffer s address and | |
102 | * capacity (in the units of sizeof(Tp)), or a pair of 0 values if | |
103 | * no storage can be obtained." Note that the capacity obtained | |
104 | * may be less than that requested if the memory is unavailable; | |
105 | * you should compare len with the .second return value. | |
106 | * | |
107 | * Provides the nothrow exception guarantee. | |
5acf59f8 BK |
108 | */ |
109 | template<typename _Tp> | |
dafa8871 | 110 | inline pair<_Tp*, ptrdiff_t> |
5acf59f8 | 111 | get_temporary_buffer(ptrdiff_t __len) |
917a9fd4 | 112 | { return std::__get_temporary_buffer(__len, static_cast<_Tp*>(0)); } |
16ad69a1 JR |
113 | |
114 | /** | |
5acf59f8 BK |
115 | * @brief The companion to get_temporary_buffer(). |
116 | * @param p A buffer previously allocated by get_temporary_buffer. | |
117 | * @return None. | |
16ad69a1 | 118 | * |
5acf59f8 BK |
119 | * Frees the memory pointed to by p. |
120 | */ | |
121 | template<typename _Tp> | |
122 | void | |
123 | return_temporary_buffer(_Tp* __p) | |
917a9fd4 | 124 | { ::operator delete(__p, nothrow); } |
54c1bf78 | 125 | |
16ad69a1 | 126 | /** |
917a9fd4 SW |
127 | * A wrapper class to provide auto_ptr with reference semantics. |
128 | * For example, an auto_ptr can be assigned (or constructed from) | |
129 | * the result of a function which returns an auto_ptr by value. | |
16ad69a1 | 130 | * |
5acf59f8 BK |
131 | * All the auto_ptr_ref stuff should happen behind the scenes. |
132 | */ | |
133 | template<typename _Tp1> | |
134 | struct auto_ptr_ref | |
135 | { | |
136 | _Tp1* _M_ptr; | |
137 | ||
138 | explicit | |
139 | auto_ptr_ref(_Tp1* __p): _M_ptr(__p) { } | |
140 | }; | |
16ad69a1 | 141 | |
16ad69a1 JR |
142 | |
143 | /** | |
5acf59f8 | 144 | * @brief A simple smart pointer providing strict ownership semantics. |
16ad69a1 | 145 | * |
5acf59f8 BK |
146 | * The Standard says: |
147 | * <pre> | |
917a9fd4 SW |
148 | * An @c auto_ptr owns the object it holds a pointer to. Copying |
149 | * an @c auto_ptr copies the pointer and transfers ownership to the | |
150 | * destination. If more than one @c auto_ptr owns the same object | |
151 | * at the same time the behavior of the program is undefined. | |
16ad69a1 | 152 | * |
917a9fd4 SW |
153 | * The uses of @c auto_ptr include providing temporary |
154 | * exception-safety for dynamically allocated memory, passing | |
155 | * ownership of dynamically allocated memory to a function, and | |
156 | * returning dynamically allocated memory from a function. @c | |
157 | * auto_ptr does not meet the CopyConstructible and Assignable | |
158 | * requirements for Standard Library <a | |
159 | * href="tables.html#65">container</a> elements and thus | |
160 | * instantiating a Standard Library container with an @c auto_ptr | |
161 | * results in undefined behavior. | |
5acf59f8 BK |
162 | * </pre> |
163 | * Quoted from [20.4.5]/3. | |
16ad69a1 | 164 | * |
917a9fd4 SW |
165 | * Good examples of what can and cannot be done with auto_ptr can |
166 | * be found in the libstdc++ testsuite. | |
16ad69a1 | 167 | * |
5acf59f8 | 168 | * @if maint |
3d7c150e | 169 | * _GLIBCXX_RESOLVE_LIB_DEFECTS |
5acf59f8 BK |
170 | * 127. auto_ptr<> conversion issues |
171 | * These resolutions have all been incorporated. | |
172 | * @endif | |
173 | */ | |
174 | template<typename _Tp> | |
175 | class auto_ptr | |
16ad69a1 | 176 | { |
5acf59f8 BK |
177 | private: |
178 | _Tp* _M_ptr; | |
179 | ||
180 | public: | |
181 | /// The pointed-to type. | |
182 | typedef _Tp element_type; | |
183 | ||
184 | /** | |
185 | * @brief An %auto_ptr is usually constructed from a raw pointer. | |
186 | * @param p A pointer (defaults to NULL). | |
187 | * | |
188 | * This object now @e owns the object pointed to by @a p. | |
189 | */ | |
190 | explicit | |
191 | auto_ptr(element_type* __p = 0) throw() : _M_ptr(__p) { } | |
192 | ||
193 | /** | |
194 | * @brief An %auto_ptr can be constructed from another %auto_ptr. | |
195 | * @param a Another %auto_ptr of the same type. | |
196 | * | |
197 | * This object now @e owns the object previously owned by @a a, | |
198 | * which has given up ownsership. | |
199 | */ | |
200 | auto_ptr(auto_ptr& __a) throw() : _M_ptr(__a.release()) { } | |
201 | ||
202 | /** | |
203 | * @brief An %auto_ptr can be constructed from another %auto_ptr. | |
204 | * @param a Another %auto_ptr of a different but related type. | |
205 | * | |
917a9fd4 SW |
206 | * A pointer-to-Tp1 must be convertible to a |
207 | * pointer-to-Tp/element_type. | |
5acf59f8 BK |
208 | * |
209 | * This object now @e owns the object previously owned by @a a, | |
210 | * which has given up ownsership. | |
211 | */ | |
212 | template<typename _Tp1> | |
213 | auto_ptr(auto_ptr<_Tp1>& __a) throw() : _M_ptr(__a.release()) { } | |
214 | ||
215 | /** | |
216 | * @brief %auto_ptr assignment operator. | |
217 | * @param a Another %auto_ptr of the same type. | |
218 | * | |
219 | * This object now @e owns the object previously owned by @a a, | |
220 | * which has given up ownsership. The object that this one @e | |
221 | * used to own and track has been deleted. | |
222 | */ | |
223 | auto_ptr& | |
224 | operator=(auto_ptr& __a) throw() | |
225 | { | |
226 | reset(__a.release()); | |
227 | return *this; | |
228 | } | |
229 | ||
230 | /** | |
231 | * @brief %auto_ptr assignment operator. | |
232 | * @param a Another %auto_ptr of a different but related type. | |
233 | * | |
234 | * A pointer-to-Tp1 must be convertible to a pointer-to-Tp/element_type. | |
235 | * | |
236 | * This object now @e owns the object previously owned by @a a, | |
237 | * which has given up ownsership. The object that this one @e | |
238 | * used to own and track has been deleted. | |
239 | */ | |
240 | template<typename _Tp1> | |
241 | auto_ptr& | |
242 | operator=(auto_ptr<_Tp1>& __a) throw() | |
16ad69a1 | 243 | { |
5acf59f8 BK |
244 | reset(__a.release()); |
245 | return *this; | |
246 | } | |
247 | ||
248 | /** | |
917a9fd4 SW |
249 | * When the %auto_ptr goes out of scope, the object it owns is |
250 | * deleted. If it no longer owns anything (i.e., @c get() is | |
251 | * @c NULL), then this has no effect. | |
5acf59f8 BK |
252 | * |
253 | * @if maint | |
254 | * The C++ standard says there is supposed to be an empty throw | |
255 | * specification here, but omitting it is standard conforming. Its | |
256 | * presence can be detected only if _Tp::~_Tp() throws, but this is | |
257 | * prohibited. [17.4.3.6]/2 | |
20fff8cd | 258 | * @endif |
5acf59f8 BK |
259 | */ |
260 | ~auto_ptr() { delete _M_ptr; } | |
261 | ||
262 | /** | |
263 | * @brief Smart pointer dereferencing. | |
264 | * | |
265 | * If this %auto_ptr no longer owns anything, then this | |
266 | * operation will crash. (For a smart pointer, "no longer owns | |
267 | * anything" is the same as being a null pointer, and you know | |
268 | * what happens when you dereference one of those...) | |
269 | */ | |
270 | element_type& | |
285b36d6 BK |
271 | operator*() const throw() |
272 | { | |
273 | _GLIBCXX_DEBUG_ASSERT(_M_ptr != 0); | |
274 | return *_M_ptr; | |
275 | } | |
5acf59f8 BK |
276 | |
277 | /** | |
278 | * @brief Smart pointer dereferencing. | |
279 | * | |
280 | * This returns the pointer itself, which the language then will | |
281 | * automatically cause to be dereferenced. | |
282 | */ | |
283 | element_type* | |
285b36d6 BK |
284 | operator->() const throw() |
285 | { | |
286 | _GLIBCXX_DEBUG_ASSERT(_M_ptr != 0); | |
287 | return _M_ptr; | |
288 | } | |
5acf59f8 BK |
289 | |
290 | /** | |
291 | * @brief Bypassing the smart pointer. | |
292 | * @return The raw pointer being managed. | |
293 | * | |
294 | * You can get a copy of the pointer that this object owns, for | |
917a9fd4 SW |
295 | * situations such as passing to a function which only accepts |
296 | * a raw pointer. | |
5acf59f8 BK |
297 | * |
298 | * @note This %auto_ptr still owns the memory. | |
299 | */ | |
300 | element_type* | |
301 | get() const throw() { return _M_ptr; } | |
302 | ||
303 | /** | |
304 | * @brief Bypassing the smart pointer. | |
305 | * @return The raw pointer being managed. | |
306 | * | |
307 | * You can get a copy of the pointer that this object owns, for | |
917a9fd4 SW |
308 | * situations such as passing to a function which only accepts |
309 | * a raw pointer. | |
5acf59f8 BK |
310 | * |
311 | * @note This %auto_ptr no longer owns the memory. When this object | |
312 | * goes out of scope, nothing will happen. | |
313 | */ | |
314 | element_type* | |
315 | release() throw() | |
316 | { | |
317 | element_type* __tmp = _M_ptr; | |
318 | _M_ptr = 0; | |
319 | return __tmp; | |
320 | } | |
321 | ||
322 | /** | |
323 | * @brief Forcibly deletes the managed object. | |
324 | * @param p A pointer (defaults to NULL). | |
325 | * | |
917a9fd4 SW |
326 | * This object now @e owns the object pointed to by @a p. The |
327 | * previous object has been deleted. | |
5acf59f8 BK |
328 | */ |
329 | void | |
330 | reset(element_type* __p = 0) throw() | |
331 | { | |
332 | if (__p != _M_ptr) | |
333 | { | |
334 | delete _M_ptr; | |
335 | _M_ptr = __p; | |
336 | } | |
337 | } | |
338 | ||
6309eefc | 339 | /** |
5acf59f8 BK |
340 | * @brief Automatic conversions |
341 | * | |
342 | * These operations convert an %auto_ptr into and from an auto_ptr_ref | |
343 | * automatically as needed. This allows constructs such as | |
344 | * @code | |
345 | * auto_ptr<Derived> func_returning_auto_ptr(.....); | |
346 | * ... | |
347 | * auto_ptr<Base> ptr = func_returning_auto_ptr(.....); | |
348 | * @endcode | |
349 | */ | |
350 | auto_ptr(auto_ptr_ref<element_type> __ref) throw() | |
351 | : _M_ptr(__ref._M_ptr) { } | |
352 | ||
353 | auto_ptr& | |
354 | operator=(auto_ptr_ref<element_type> __ref) throw() | |
355 | { | |
356 | if (__ref._M_ptr != this->get()) | |
357 | { | |
358 | delete _M_ptr; | |
359 | _M_ptr = __ref._M_ptr; | |
360 | } | |
361 | return *this; | |
362 | } | |
363 | ||
364 | template<typename _Tp1> | |
365 | operator auto_ptr_ref<_Tp1>() throw() | |
366 | { return auto_ptr_ref<_Tp1>(this->release()); } | |
367 | ||
368 | template<typename _Tp1> | |
369 | operator auto_ptr<_Tp1>() throw() | |
370 | { return auto_ptr<_Tp1>(this->release()); } | |
5acf59f8 | 371 | }; |
54c1bf78 BK |
372 | } // namespace std |
373 | ||
1143680e | 374 | #endif /* _GLIBCXX_MEMORY */ |