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6cb784b6 TS |
1 | // class template regex -*- C++ -*- |
2 | ||
cbe34bb5 | 3 | // Copyright (C) 2013-2017 Free Software Foundation, Inc. |
6cb784b6 TS |
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 | /** | |
26 | * @file bits/regex_executor.tcc | |
27 | * This is an internal header file, included by other library headers. | |
28 | * Do not attempt to use it directly. @headername{regex} | |
29 | */ | |
30 | ||
31 | namespace std _GLIBCXX_VISIBILITY(default) | |
32 | { | |
6cb784b6 TS |
33 | _GLIBCXX_BEGIN_NAMESPACE_VERSION |
34 | ||
4a15d842 FD |
35 | namespace __detail |
36 | { | |
9f0d9611 | 37 | template<typename _BiIter, typename _Alloc, typename _TraitsT, |
097f0bcf | 38 | bool __dfs_mode> |
9f0d9611 | 39 | bool _Executor<_BiIter, _Alloc, _TraitsT, __dfs_mode>:: |
18971f1f TS |
40 | _M_search() |
41 | { | |
02ba3fc2 TS |
42 | if (_M_search_from_first()) |
43 | return true; | |
18971f1f | 44 | if (_M_flags & regex_constants::match_continuous) |
02ba3fc2 TS |
45 | return false; |
46 | _M_flags |= regex_constants::match_prev_avail; | |
47 | while (_M_begin != _M_end) | |
18971f1f | 48 | { |
02ba3fc2 TS |
49 | ++_M_begin; |
50 | if (_M_search_from_first()) | |
18971f1f TS |
51 | return true; |
52 | } | |
18971f1f TS |
53 | return false; |
54 | } | |
55 | ||
097f0bcf JW |
56 | // The _M_main function operates in different modes, DFS mode or BFS mode, |
57 | // indicated by template parameter __dfs_mode, and dispatches to one of the | |
58 | // _M_main_dispatch overloads. | |
caaf33fa TS |
59 | // |
60 | // ------------------------------------------------------------ | |
61 | // | |
62 | // DFS mode: | |
63 | // | |
64 | // It applies a Depth-First-Search (aka backtracking) on given NFA and input | |
65 | // string. | |
097f0bcf JW |
66 | // At the very beginning the executor stands in the start state, then it |
67 | // tries every possible state transition in current state recursively. Some | |
68 | // state transitions consume input string, say, a single-char-matcher or a | |
caaf33fa | 69 | // back-reference matcher; some don't, like assertion or other anchor nodes. |
097f0bcf JW |
70 | // When the input is exhausted and/or the current state is an accepting |
71 | // state, the whole executor returns true. | |
caaf33fa TS |
72 | // |
73 | // TODO: This approach is exponentially slow for certain input. | |
74 | // Try to compile the NFA to a DFA. | |
75 | // | |
ee54a3b3 | 76 | // Time complexity: \Omega(match_length), O(2^(_M_nfa.size())) |
caaf33fa TS |
77 | // Space complexity: \theta(match_results.size() + match_length) |
78 | // | |
097f0bcf JW |
79 | template<typename _BiIter, typename _Alloc, typename _TraitsT, |
80 | bool __dfs_mode> | |
81 | bool _Executor<_BiIter, _Alloc, _TraitsT, __dfs_mode>:: | |
82 | _M_main_dispatch(_Match_mode __match_mode, __dfs) | |
83 | { | |
84 | _M_has_sol = false; | |
ad9ec7b3 | 85 | *_M_states._M_get_sol_pos() = _BiIter(); |
097f0bcf JW |
86 | _M_cur_results = _M_results; |
87 | _M_dfs(__match_mode, _M_states._M_start); | |
88 | return _M_has_sol; | |
89 | } | |
90 | ||
caaf33fa TS |
91 | // ------------------------------------------------------------ |
92 | // | |
93 | // BFS mode: | |
94 | // | |
95 | // Russ Cox's article (http://swtch.com/~rsc/regexp/regexp1.html) | |
96 | // explained this algorithm clearly. | |
97 | // | |
ee54a3b3 TS |
98 | // It first computes epsilon closure (states that can be achieved without |
99 | // consuming characters) for every state that's still matching, | |
097f0bcf JW |
100 | // using the same DFS algorithm, but doesn't re-enter states (using |
101 | // _M_states._M_visited to check), nor follow _S_opcode_match. | |
caaf33fa | 102 | // |
097f0bcf JW |
103 | // Then apply DFS using every _S_opcode_match (in _M_states._M_match_queue) |
104 | // as the start state. | |
caaf33fa TS |
105 | // |
106 | // It significantly reduces potential duplicate states, so has a better | |
107 | // upper bound; but it requires more overhead. | |
108 | // | |
ee54a3b3 | 109 | // Time complexity: \Omega(match_length * match_results.size()) |
caaf33fa | 110 | // O(match_length * _M_nfa.size() * match_results.size()) |
ee54a3b3 | 111 | // Space complexity: \Omega(_M_nfa.size() + match_results.size()) |
caaf33fa | 112 | // O(_M_nfa.size() * match_results.size()) |
9f0d9611 | 113 | template<typename _BiIter, typename _Alloc, typename _TraitsT, |
097f0bcf | 114 | bool __dfs_mode> |
9f0d9611 | 115 | bool _Executor<_BiIter, _Alloc, _TraitsT, __dfs_mode>:: |
097f0bcf | 116 | _M_main_dispatch(_Match_mode __match_mode, __bfs) |
9f0d9611 | 117 | { |
097f0bcf JW |
118 | _M_states._M_queue(_M_states._M_start, _M_results); |
119 | bool __ret = false; | |
120 | while (1) | |
9f0d9611 TS |
121 | { |
122 | _M_has_sol = false; | |
097f0bcf JW |
123 | if (_M_states._M_match_queue.empty()) |
124 | break; | |
125 | std::fill_n(_M_states._M_visited_states.get(), _M_nfa.size(), false); | |
126 | auto __old_queue = std::move(_M_states._M_match_queue); | |
127 | for (auto& __task : __old_queue) | |
9f0d9611 | 128 | { |
097f0bcf JW |
129 | _M_cur_results = std::move(__task.second); |
130 | _M_dfs(__match_mode, __task.first); | |
9f0d9611 | 131 | } |
097f0bcf JW |
132 | if (__match_mode == _Match_mode::_Prefix) |
133 | __ret |= _M_has_sol; | |
134 | if (_M_current == _M_end) | |
135 | break; | |
136 | ++_M_current; | |
9f0d9611 | 137 | } |
097f0bcf JW |
138 | if (__match_mode == _Match_mode::_Exact) |
139 | __ret = _M_has_sol; | |
4228f932 | 140 | _M_states._M_match_queue.clear(); |
097f0bcf | 141 | return __ret; |
9f0d9611 TS |
142 | } |
143 | ||
144 | // Return whether now match the given sub-NFA. | |
145 | template<typename _BiIter, typename _Alloc, typename _TraitsT, | |
097f0bcf | 146 | bool __dfs_mode> |
9f0d9611 | 147 | bool _Executor<_BiIter, _Alloc, _TraitsT, __dfs_mode>:: |
81b7ff07 | 148 | _M_lookahead(_StateIdT __next) |
9f0d9611 | 149 | { |
3ce38f68 TS |
150 | // Backreferences may refer to captured content. |
151 | // We may want to make this faster by not copying, | |
152 | // but let's not be clever prematurely. | |
153 | _ResultsVec __what(_M_cur_results); | |
097f0bcf | 154 | _Executor __sub(_M_current, _M_end, __what, _M_re, _M_flags); |
81b7ff07 | 155 | __sub._M_states._M_start = __next; |
097f0bcf | 156 | if (__sub._M_search_from_first()) |
9f0d9611 TS |
157 | { |
158 | for (size_t __i = 0; __i < __what.size(); __i++) | |
159 | if (__what[__i].matched) | |
160 | _M_cur_results[__i] = __what[__i]; | |
161 | return true; | |
162 | } | |
163 | return false; | |
164 | } | |
165 | ||
a670a9bb TS |
166 | // __rep_count records how many times (__rep_count.second) |
167 | // this node is visited under certain input iterator | |
168 | // (__rep_count.first). This prevent the executor from entering | |
169 | // infinite loop by refusing to continue when it's already been | |
170 | // visited more than twice. It's `twice` instead of `once` because | |
171 | // we need to spare one more time for potential group capture. | |
172 | template<typename _BiIter, typename _Alloc, typename _TraitsT, | |
173 | bool __dfs_mode> | |
a670a9bb | 174 | void _Executor<_BiIter, _Alloc, _TraitsT, __dfs_mode>:: |
097f0bcf | 175 | _M_rep_once_more(_Match_mode __match_mode, _StateIdT __i) |
a670a9bb TS |
176 | { |
177 | const auto& __state = _M_nfa[__i]; | |
178 | auto& __rep_count = _M_rep_count[__i]; | |
179 | if (__rep_count.second == 0 || __rep_count.first != _M_current) | |
180 | { | |
181 | auto __back = __rep_count; | |
182 | __rep_count.first = _M_current; | |
183 | __rep_count.second = 1; | |
097f0bcf | 184 | _M_dfs(__match_mode, __state._M_alt); |
a670a9bb TS |
185 | __rep_count = __back; |
186 | } | |
187 | else | |
188 | { | |
189 | if (__rep_count.second < 2) | |
190 | { | |
191 | __rep_count.second++; | |
097f0bcf | 192 | _M_dfs(__match_mode, __state._M_alt); |
a670a9bb TS |
193 | __rep_count.second--; |
194 | } | |
195 | } | |
196 | }; | |
197 | ||
d79d6252 TS |
198 | // _M_alt branch is "match once more", while _M_next is "get me out |
199 | // of this quantifier". Executing _M_next first or _M_alt first don't | |
200 | // mean the same thing, and we need to choose the correct order under | |
201 | // given greedy mode. | |
9f0d9611 | 202 | template<typename _BiIter, typename _Alloc, typename _TraitsT, |
097f0bcf | 203 | bool __dfs_mode> |
9f0d9611 | 204 | void _Executor<_BiIter, _Alloc, _TraitsT, __dfs_mode>:: |
d79d6252 | 205 | _M_handle_repeat(_Match_mode __match_mode, _StateIdT __i) |
6cb784b6 | 206 | { |
9f0d9611 | 207 | const auto& __state = _M_nfa[__i]; |
d79d6252 TS |
208 | |
209 | // Greedy. | |
210 | if (!__state._M_neg) | |
e280b6ff | 211 | { |
d79d6252 TS |
212 | _M_rep_once_more(__match_mode, __i); |
213 | // If it's DFS executor and already accepted, we're done. | |
214 | if (!__dfs_mode || !_M_has_sol) | |
097f0bcf | 215 | _M_dfs(__match_mode, __state._M_next); |
d79d6252 TS |
216 | } |
217 | else // Non-greedy mode | |
218 | { | |
9f0d9611 | 219 | if (__dfs_mode) |
e280b6ff | 220 | { |
d79d6252 TS |
221 | // vice-versa. |
222 | _M_dfs(__match_mode, __state._M_next); | |
223 | if (!_M_has_sol) | |
224 | _M_rep_once_more(__match_mode, __i); | |
e280b6ff | 225 | } |
9f0d9611 | 226 | else |
e280b6ff | 227 | { |
d79d6252 TS |
228 | // DON'T attempt anything, because there's already another |
229 | // state with higher priority accepted. This state cannot | |
230 | // be better by attempting its next node. | |
231 | if (!_M_has_sol) | |
ad9ec7b3 | 232 | { |
d79d6252 TS |
233 | _M_dfs(__match_mode, __state._M_next); |
234 | // DON'T attempt anything if it's already accepted. An | |
235 | // accepted state *must* be better than a solution that | |
236 | // matches a non-greedy quantifier one more time. | |
237 | if (!_M_has_sol) | |
238 | _M_rep_once_more(__match_mode, __i); | |
ad9ec7b3 | 239 | } |
e280b6ff | 240 | } |
d79d6252 TS |
241 | } |
242 | } | |
243 | ||
244 | template<typename _BiIter, typename _Alloc, typename _TraitsT, | |
245 | bool __dfs_mode> | |
246 | void _Executor<_BiIter, _Alloc, _TraitsT, __dfs_mode>:: | |
247 | _M_handle_subexpr_begin(_Match_mode __match_mode, _StateIdT __i) | |
248 | { | |
249 | const auto& __state = _M_nfa[__i]; | |
250 | ||
251 | auto& __res = _M_cur_results[__state._M_subexpr]; | |
252 | auto __back = __res.first; | |
253 | __res.first = _M_current; | |
254 | _M_dfs(__match_mode, __state._M_next); | |
255 | __res.first = __back; | |
256 | } | |
257 | ||
258 | template<typename _BiIter, typename _Alloc, typename _TraitsT, | |
259 | bool __dfs_mode> | |
260 | void _Executor<_BiIter, _Alloc, _TraitsT, __dfs_mode>:: | |
261 | _M_handle_subexpr_end(_Match_mode __match_mode, _StateIdT __i) | |
262 | { | |
263 | const auto& __state = _M_nfa[__i]; | |
264 | ||
265 | auto& __res = _M_cur_results[__state._M_subexpr]; | |
266 | auto __back = __res; | |
267 | __res.second = _M_current; | |
268 | __res.matched = true; | |
269 | _M_dfs(__match_mode, __state._M_next); | |
270 | __res = __back; | |
271 | } | |
272 | ||
273 | template<typename _BiIter, typename _Alloc, typename _TraitsT, | |
274 | bool __dfs_mode> | |
275 | inline void _Executor<_BiIter, _Alloc, _TraitsT, __dfs_mode>:: | |
276 | _M_handle_line_begin_assertion(_Match_mode __match_mode, _StateIdT __i) | |
277 | { | |
278 | const auto& __state = _M_nfa[__i]; | |
279 | if (_M_at_begin()) | |
280 | _M_dfs(__match_mode, __state._M_next); | |
281 | } | |
282 | ||
283 | template<typename _BiIter, typename _Alloc, typename _TraitsT, | |
284 | bool __dfs_mode> | |
285 | inline void _Executor<_BiIter, _Alloc, _TraitsT, __dfs_mode>:: | |
286 | _M_handle_line_end_assertion(_Match_mode __match_mode, _StateIdT __i) | |
287 | { | |
288 | const auto& __state = _M_nfa[__i]; | |
289 | if (_M_at_end()) | |
290 | _M_dfs(__match_mode, __state._M_next); | |
291 | } | |
292 | ||
293 | template<typename _BiIter, typename _Alloc, typename _TraitsT, | |
294 | bool __dfs_mode> | |
295 | inline void _Executor<_BiIter, _Alloc, _TraitsT, __dfs_mode>:: | |
296 | _M_handle_word_boundary(_Match_mode __match_mode, _StateIdT __i) | |
297 | { | |
298 | const auto& __state = _M_nfa[__i]; | |
299 | if (_M_word_boundary() == !__state._M_neg) | |
300 | _M_dfs(__match_mode, __state._M_next); | |
301 | } | |
302 | ||
303 | // Here __state._M_alt offers a single start node for a sub-NFA. | |
304 | // We recursively invoke our algorithm to match the sub-NFA. | |
305 | template<typename _BiIter, typename _Alloc, typename _TraitsT, | |
306 | bool __dfs_mode> | |
307 | void _Executor<_BiIter, _Alloc, _TraitsT, __dfs_mode>:: | |
308 | _M_handle_subexpr_lookahead(_Match_mode __match_mode, _StateIdT __i) | |
309 | { | |
310 | const auto& __state = _M_nfa[__i]; | |
311 | if (_M_lookahead(__state._M_alt) == !__state._M_neg) | |
312 | _M_dfs(__match_mode, __state._M_next); | |
313 | } | |
314 | ||
315 | template<typename _BiIter, typename _Alloc, typename _TraitsT, | |
316 | bool __dfs_mode> | |
317 | void _Executor<_BiIter, _Alloc, _TraitsT, __dfs_mode>:: | |
318 | _M_handle_match(_Match_mode __match_mode, _StateIdT __i) | |
319 | { | |
320 | const auto& __state = _M_nfa[__i]; | |
321 | ||
322 | if (_M_current == _M_end) | |
323 | return; | |
324 | if (__dfs_mode) | |
325 | { | |
326 | if (__state._M_matches(*_M_current)) | |
18971f1f | 327 | { |
d79d6252 TS |
328 | ++_M_current; |
329 | _M_dfs(__match_mode, __state._M_next); | |
330 | --_M_current; | |
18971f1f | 331 | } |
d79d6252 TS |
332 | } |
333 | else | |
334 | if (__state._M_matches(*_M_current)) | |
335 | _M_states._M_queue(__state._M_next, _M_cur_results); | |
336 | } | |
337 | ||
338 | // First fetch the matched result from _M_cur_results as __submatch; | |
339 | // then compare it with | |
340 | // (_M_current, _M_current + (__submatch.second - __submatch.first)). | |
341 | // If matched, keep going; else just return and try another state. | |
342 | template<typename _BiIter, typename _Alloc, typename _TraitsT, | |
343 | bool __dfs_mode> | |
344 | void _Executor<_BiIter, _Alloc, _TraitsT, __dfs_mode>:: | |
345 | _M_handle_backref(_Match_mode __match_mode, _StateIdT __i) | |
346 | { | |
347 | __glibcxx_assert(__dfs_mode); | |
348 | ||
349 | const auto& __state = _M_nfa[__i]; | |
350 | auto& __submatch = _M_cur_results[__state._M_backref_index]; | |
351 | if (!__submatch.matched) | |
352 | return; | |
353 | auto __last = _M_current; | |
354 | for (auto __tmp = __submatch.first; | |
355 | __last != _M_end && __tmp != __submatch.second; | |
356 | ++__tmp) | |
357 | ++__last; | |
358 | if (_M_re._M_automaton->_M_traits.transform(__submatch.first, | |
359 | __submatch.second) | |
360 | == _M_re._M_automaton->_M_traits.transform(_M_current, __last)) | |
361 | { | |
362 | if (__last != _M_current) | |
ad9ec7b3 | 363 | { |
d79d6252 TS |
364 | auto __backup = _M_current; |
365 | _M_current = __last; | |
366 | _M_dfs(__match_mode, __state._M_next); | |
367 | _M_current = __backup; | |
ad9ec7b3 TS |
368 | } |
369 | else | |
d79d6252 TS |
370 | _M_dfs(__match_mode, __state._M_next); |
371 | } | |
372 | } | |
373 | ||
374 | template<typename _BiIter, typename _Alloc, typename _TraitsT, | |
375 | bool __dfs_mode> | |
376 | void _Executor<_BiIter, _Alloc, _TraitsT, __dfs_mode>:: | |
377 | _M_handle_accept(_Match_mode __match_mode, _StateIdT __i) | |
378 | { | |
379 | if (__dfs_mode) | |
380 | { | |
381 | __glibcxx_assert(!_M_has_sol); | |
382 | if (__match_mode == _Match_mode::_Exact) | |
383 | _M_has_sol = _M_current == _M_end; | |
384 | else | |
385 | _M_has_sol = true; | |
386 | if (_M_current == _M_begin | |
387 | && (_M_flags & regex_constants::match_not_null)) | |
388 | _M_has_sol = false; | |
389 | if (_M_has_sol) | |
ad9ec7b3 | 390 | { |
d79d6252 TS |
391 | if (_M_nfa._M_flags & regex_constants::ECMAScript) |
392 | _M_results = _M_cur_results; | |
393 | else // POSIX | |
394 | { | |
395 | __glibcxx_assert(_M_states._M_get_sol_pos()); | |
396 | // Here's POSIX's logic: match the longest one. However | |
397 | // we never know which one (lhs or rhs of "|") is longer | |
398 | // unless we try both of them and compare the results. | |
399 | // The member variable _M_sol_pos records the end | |
400 | // position of the last successful match. It's better | |
401 | // to be larger, because POSIX regex is always greedy. | |
402 | // TODO: This could be slow. | |
403 | if (*_M_states._M_get_sol_pos() == _BiIter() | |
404 | || std::distance(_M_begin, | |
405 | *_M_states._M_get_sol_pos()) | |
406 | < std::distance(_M_begin, _M_current)) | |
407 | { | |
408 | *_M_states._M_get_sol_pos() = _M_current; | |
409 | _M_results = _M_cur_results; | |
410 | } | |
411 | } | |
ad9ec7b3 | 412 | } |
d79d6252 TS |
413 | } |
414 | else | |
415 | { | |
416 | if (_M_current == _M_begin | |
417 | && (_M_flags & regex_constants::match_not_null)) | |
418 | return; | |
419 | if (__match_mode == _Match_mode::_Prefix || _M_current == _M_end) | |
420 | if (!_M_has_sol) | |
421 | { | |
422 | _M_has_sol = true; | |
423 | _M_results = _M_cur_results; | |
424 | } | |
425 | } | |
426 | } | |
427 | ||
428 | template<typename _BiIter, typename _Alloc, typename _TraitsT, | |
429 | bool __dfs_mode> | |
430 | void _Executor<_BiIter, _Alloc, _TraitsT, __dfs_mode>:: | |
431 | _M_handle_alternative(_Match_mode __match_mode, _StateIdT __i) | |
432 | { | |
433 | const auto& __state = _M_nfa[__i]; | |
434 | ||
435 | if (_M_nfa._M_flags & regex_constants::ECMAScript) | |
436 | { | |
437 | // TODO: Fix BFS support. It is wrong. | |
438 | _M_dfs(__match_mode, __state._M_alt); | |
439 | // Pick lhs if it matches. Only try rhs if it doesn't. | |
440 | if (!_M_has_sol) | |
441 | _M_dfs(__match_mode, __state._M_next); | |
442 | } | |
443 | else | |
444 | { | |
445 | // Try both and compare the result. | |
446 | // See "case _S_opcode_accept:" handling above. | |
447 | _M_dfs(__match_mode, __state._M_alt); | |
448 | auto __has_sol = _M_has_sol; | |
449 | _M_has_sol = false; | |
450 | _M_dfs(__match_mode, __state._M_next); | |
451 | _M_has_sol |= __has_sol; | |
452 | } | |
453 | } | |
454 | ||
455 | template<typename _BiIter, typename _Alloc, typename _TraitsT, | |
456 | bool __dfs_mode> | |
457 | void _Executor<_BiIter, _Alloc, _TraitsT, __dfs_mode>:: | |
458 | _M_dfs(_Match_mode __match_mode, _StateIdT __i) | |
459 | { | |
460 | if (_M_states._M_visited(__i)) | |
461 | return; | |
462 | ||
463 | switch (_M_nfa[__i]._M_opcode()) | |
464 | { | |
465 | case _S_opcode_repeat: | |
466 | _M_handle_repeat(__match_mode, __i); break; | |
467 | case _S_opcode_subexpr_begin: | |
468 | _M_handle_subexpr_begin(__match_mode, __i); break; | |
469 | case _S_opcode_subexpr_end: | |
470 | _M_handle_subexpr_end(__match_mode, __i); break; | |
471 | case _S_opcode_line_begin_assertion: | |
472 | _M_handle_line_begin_assertion(__match_mode, __i); break; | |
473 | case _S_opcode_line_end_assertion: | |
474 | _M_handle_line_end_assertion(__match_mode, __i); break; | |
475 | case _S_opcode_word_boundary: | |
476 | _M_handle_word_boundary(__match_mode, __i); break; | |
477 | case _S_opcode_subexpr_lookahead: | |
478 | _M_handle_subexpr_lookahead(__match_mode, __i); break; | |
479 | case _S_opcode_match: | |
480 | _M_handle_match(__match_mode, __i); break; | |
481 | case _S_opcode_backref: | |
482 | _M_handle_backref(__match_mode, __i); break; | |
483 | case _S_opcode_accept: | |
484 | _M_handle_accept(__match_mode, __i); break; | |
485 | case _S_opcode_alternative: | |
486 | _M_handle_alternative(__match_mode, __i); break; | |
9f0d9611 | 487 | default: |
2f1e8e7c | 488 | __glibcxx_assert(false); |
e280b6ff | 489 | } |
6cb784b6 TS |
490 | } |
491 | ||
f054ff5b | 492 | // Return whether now is at some word boundary. |
9f0d9611 | 493 | template<typename _BiIter, typename _Alloc, typename _TraitsT, |
097f0bcf | 494 | bool __dfs_mode> |
9f0d9611 | 495 | bool _Executor<_BiIter, _Alloc, _TraitsT, __dfs_mode>:: |
4d838433 | 496 | _M_word_boundary() const |
b21abcee | 497 | { |
216f7526 TS |
498 | if (_M_current == _M_begin && (_M_flags & regex_constants::match_not_bow)) |
499 | return false; | |
500 | if (_M_current == _M_end && (_M_flags & regex_constants::match_not_eow)) | |
501 | return false; | |
502 | ||
4d838433 TS |
503 | bool __left_is_word = false; |
504 | if (_M_current != _M_begin | |
505 | || (_M_flags & regex_constants::match_prev_avail)) | |
ab1c993b | 506 | { |
4d838433 TS |
507 | auto __prev = _M_current; |
508 | if (_M_is_word(*std::prev(__prev))) | |
509 | __left_is_word = true; | |
ab1c993b | 510 | } |
4d838433 TS |
511 | bool __right_is_word = |
512 | _M_current != _M_end && _M_is_word(*_M_current); | |
513 | ||
216f7526 | 514 | return __left_is_word != __right_is_word; |
b21abcee | 515 | } |
4a15d842 | 516 | } // namespace __detail |
b21abcee | 517 | |
6cb784b6 | 518 | _GLIBCXX_END_NAMESPACE_VERSION |
6cb784b6 | 519 | } // namespace |