source: Daodan/MSYS2/mingw32/include/c++/11.2.0/debug/helper_functions.h@ 1182

Last change on this file since 1182 was 1166, checked in by rossy, 3 years ago

Daodan: Replace MinGW build env with an up-to-date MSYS2 env
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1// Debugging support implementation -*- C++ -*-
2
3// Copyright (C) 2003-2021 Free Software Foundation, Inc.
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 3, 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// 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.
19
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/>.
24
25/** @file debug/helper_functions.h
26 * This file is a GNU debug extension to the Standard C++ Library.
27 */
28
29#ifndef _GLIBCXX_DEBUG_HELPER_FUNCTIONS_H
30#define _GLIBCXX_DEBUG_HELPER_FUNCTIONS_H 1
31
32#include <bits/move.h> // for __addressof
33#include <bits/stl_iterator_base_types.h> // for iterator_traits,
34 // categories and _Iter_base
35#include <bits/cpp_type_traits.h> // for __is_integer
36
37#include <bits/stl_pair.h> // for pair
38
39namespace __gnu_debug
40{
41 template<typename _Iterator, typename _Sequence, typename _Category>
42 class _Safe_iterator;
43
44#if __cplusplus >= 201103L
45 template<typename _Iterator, typename _Sequence>
46 class _Safe_local_iterator;
47#endif
48
49 /** The precision to which we can calculate the distance between
50 * two iterators.
51 */
52 enum _Distance_precision
53 {
54 __dp_none, // Not even an iterator type
55 __dp_equality, //< Can compare iterator equality, only
56 __dp_sign, //< Can determine equality and ordering
57 __dp_sign_max_size, //< __dp_sign and gives max range size
58 __dp_exact //< Can determine distance precisely
59 };
60
61 template<typename _Iterator,
62 typename = typename std::__is_integer<_Iterator>::__type>
63 struct _Distance_traits
64 {
65 private:
66 typedef
67 typename std::iterator_traits<_Iterator>::difference_type _ItDiffType;
68
69 template<typename _DiffType,
70 typename = typename std::__is_void<_DiffType>::__type>
71 struct _DiffTraits
72 { typedef _DiffType __type; };
73
74 template<typename _DiffType>
75 struct _DiffTraits<_DiffType, std::__true_type>
76 { typedef std::ptrdiff_t __type; };
77
78 typedef typename _DiffTraits<_ItDiffType>::__type _DiffType;
79
80 public:
81 typedef std::pair<_DiffType, _Distance_precision> __type;
82 };
83
84 template<typename _Integral>
85 struct _Distance_traits<_Integral, std::__true_type>
86 { typedef std::pair<std::ptrdiff_t, _Distance_precision> __type; };
87
88 /** Determine the distance between two iterators with some known
89 * precision.
90 */
91 template<typename _Iterator>
92 _GLIBCXX_CONSTEXPR
93 inline typename _Distance_traits<_Iterator>::__type
94 __get_distance(_Iterator __lhs, _Iterator __rhs,
95 std::random_access_iterator_tag)
96 { return std::make_pair(__rhs - __lhs, __dp_exact); }
97
98 template<typename _Iterator>
99 _GLIBCXX14_CONSTEXPR
100 inline typename _Distance_traits<_Iterator>::__type
101 __get_distance(_Iterator __lhs, _Iterator __rhs,
102 std::input_iterator_tag)
103 {
104 if (__lhs == __rhs)
105 return std::make_pair(0, __dp_exact);
106
107 return std::make_pair(1, __dp_equality);
108 }
109
110 template<typename _Iterator>
111 _GLIBCXX_CONSTEXPR
112 inline typename _Distance_traits<_Iterator>::__type
113 __get_distance(_Iterator __lhs, _Iterator __rhs)
114 { return __get_distance(__lhs, __rhs, std::__iterator_category(__lhs)); }
115
116 // An arbitrary iterator pointer is not singular.
117 inline bool
118 __check_singular_aux(const void*) { return false; }
119
120 // We may have an iterator that derives from _Safe_iterator_base but isn't
121 // a _Safe_iterator.
122 template<typename _Iterator>
123 _GLIBCXX_CONSTEXPR
124 inline bool
125 __check_singular(_Iterator const& __x)
126 {
127 return
128#ifdef _GLIBCXX_HAVE_BUILTIN_IS_CONSTANT_EVALUATED
129 __builtin_is_constant_evaluated() ? false :
130#endif
131 __check_singular_aux(std::__addressof(__x));
132 }
133
134 /** Non-NULL pointers are nonsingular. */
135 template<typename _Tp>
136 _GLIBCXX_CONSTEXPR
137 inline bool
138 __check_singular(_Tp* const& __ptr)
139 {
140 return
141#ifdef _GLIBCXX_HAVE_BUILTIN_IS_CONSTANT_EVALUATED
142 __builtin_is_constant_evaluated() ? false :
143#endif
144 __ptr == 0;
145 }
146
147 /** We say that integral types for a valid range, and defer to other
148 * routines to realize what to do with integral types instead of
149 * iterators.
150 */
151 template<typename _Integral>
152 _GLIBCXX_CONSTEXPR
153 inline bool
154 __valid_range_aux(_Integral, _Integral, std::__true_type)
155 { return true; }
156
157 template<typename _Integral>
158 _GLIBCXX20_CONSTEXPR
159 inline bool
160 __valid_range_aux(_Integral, _Integral,
161 typename _Distance_traits<_Integral>::__type& __dist,
162 std::__true_type)
163 {
164 __dist = std::make_pair(0, __dp_none);
165 return true;
166 }
167
168 template<typename _InputIterator>
169 _GLIBCXX_CONSTEXPR
170 inline bool
171 __valid_range_aux(_InputIterator __first, _InputIterator __last,
172 std::input_iterator_tag)
173 {
174 return __first == __last
175 || (!__check_singular(__first) && !__check_singular(__last));
176 }
177
178 template<typename _InputIterator>
179 _GLIBCXX_CONSTEXPR
180 inline bool
181 __valid_range_aux(_InputIterator __first, _InputIterator __last,
182 std::random_access_iterator_tag)
183 {
184 return
185 __valid_range_aux(__first, __last, std::input_iterator_tag())
186 && __first <= __last;
187 }
188
189 /** We have iterators, so figure out what kind of iterators they are
190 * to see if we can check the range ahead of time.
191 */
192 template<typename _InputIterator>
193 _GLIBCXX_CONSTEXPR
194 inline bool
195 __valid_range_aux(_InputIterator __first, _InputIterator __last,
196 std::__false_type)
197 {
198 return __valid_range_aux(__first, __last,
199 std::__iterator_category(__first));
200 }
201
202 template<typename _InputIterator>
203 _GLIBCXX20_CONSTEXPR
204 inline bool
205 __valid_range_aux(_InputIterator __first, _InputIterator __last,
206 typename _Distance_traits<_InputIterator>::__type& __dist,
207 std::__false_type)
208 {
209 if (!__valid_range_aux(__first, __last, std::input_iterator_tag()))
210 return false;
211
212 __dist = __get_distance(__first, __last);
213 switch (__dist.second)
214 {
215 case __dp_none:
216 break;
217 case __dp_equality:
218 if (__dist.first == 0)
219 return true;
220 break;
221 case __dp_sign:
222 case __dp_sign_max_size:
223 case __dp_exact:
224 return __dist.first >= 0;
225 }
226
227 // Can't tell so assume it is fine.
228 return true;
229 }
230
231 /** Don't know what these iterators are, or if they are even
232 * iterators (we may get an integral type for InputIterator), so
233 * see if they are integral and pass them on to the next phase
234 * otherwise.
235 */
236 template<typename _InputIterator>
237 _GLIBCXX20_CONSTEXPR
238 inline bool
239 __valid_range(_InputIterator __first, _InputIterator __last,
240 typename _Distance_traits<_InputIterator>::__type& __dist)
241 {
242 typedef typename std::__is_integer<_InputIterator>::__type _Integral;
243 return __valid_range_aux(__first, __last, __dist, _Integral());
244 }
245
246 template<typename _Iterator, typename _Sequence, typename _Category>
247 bool
248 __valid_range(const _Safe_iterator<_Iterator, _Sequence, _Category>&,
249 const _Safe_iterator<_Iterator, _Sequence, _Category>&,
250 typename _Distance_traits<_Iterator>::__type&);
251
252#if __cplusplus >= 201103L
253 template<typename _Iterator,typename _Sequence>
254 bool
255 __valid_range(const _Safe_local_iterator<_Iterator, _Sequence>&,
256 const _Safe_local_iterator<_Iterator, _Sequence>&,
257 typename _Distance_traits<_Iterator>::__type&);
258#endif
259
260 template<typename _InputIterator>
261 _GLIBCXX14_CONSTEXPR
262 inline bool
263 __valid_range(_InputIterator __first, _InputIterator __last)
264 {
265 typedef typename std::__is_integer<_InputIterator>::__type _Integral;
266 return __valid_range_aux(__first, __last, _Integral());
267 }
268
269 template<typename _Iterator, typename _Sequence, typename _Category>
270 bool
271 __valid_range(const _Safe_iterator<_Iterator, _Sequence, _Category>&,
272 const _Safe_iterator<_Iterator, _Sequence, _Category>&);
273
274#if __cplusplus >= 201103L
275 template<typename _Iterator, typename _Sequence>
276 bool
277 __valid_range(const _Safe_local_iterator<_Iterator, _Sequence>&,
278 const _Safe_local_iterator<_Iterator, _Sequence>&);
279#endif
280
281 // Fallback method, always ok.
282 template<typename _InputIterator, typename _Size>
283 _GLIBCXX_CONSTEXPR
284 inline bool
285 __can_advance(_InputIterator, _Size)
286 { return true; }
287
288 template<typename _Iterator, typename _Sequence, typename _Category,
289 typename _Size>
290 bool
291 __can_advance(const _Safe_iterator<_Iterator, _Sequence, _Category>&,
292 _Size);
293
294 template<typename _InputIterator, typename _Diff>
295 _GLIBCXX_CONSTEXPR
296 inline bool
297 __can_advance(_InputIterator, const std::pair<_Diff, _Distance_precision>&, int)
298 { return true; }
299
300 template<typename _Iterator, typename _Sequence, typename _Category,
301 typename _Diff>
302 bool
303 __can_advance(const _Safe_iterator<_Iterator, _Sequence, _Category>&,
304 const std::pair<_Diff, _Distance_precision>&, int);
305
306 /** Helper function to extract base iterator of random access safe iterator
307 * in order to reduce performance impact of debug mode. Limited to random
308 * access iterator because it is the only category for which it is possible
309 * to check for correct iterators order in the __valid_range function
310 * thanks to the < operator.
311 */
312 template<typename _Iterator>
313 _GLIBCXX_CONSTEXPR
314 inline _Iterator
315 __base(_Iterator __it)
316 { return __it; }
317
318#if __cplusplus < 201103L
319 template<typename _Iterator>
320 struct _Unsafe_type
321 { typedef _Iterator _Type; };
322#endif
323
324 /* Remove debug mode safe iterator layer, if any. */
325 template<typename _Iterator>
326 inline _Iterator
327 __unsafe(_Iterator __it)
328 { return __it; }
329}
330
331#endif
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