1 | // class template regex -*- C++ -*- |
2 | |
3 | // Copyright (C) 2013-2024 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 | /** |
26 | * @file bits/regex_automaton.h |
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 | // This macro defines the maximal state number a NFA can have. |
32 | #ifndef _GLIBCXX_REGEX_STATE_LIMIT |
33 | #define _GLIBCXX_REGEX_STATE_LIMIT 100000 |
34 | #endif |
35 | |
36 | namespace std _GLIBCXX_VISIBILITY(default) |
37 | { |
38 | _GLIBCXX_BEGIN_NAMESPACE_VERSION |
39 | |
40 | namespace __detail |
41 | { |
42 | /** |
43 | * @defgroup regex-detail Base and Implementation Classes |
44 | * @ingroup regex |
45 | * @{ |
46 | */ |
47 | |
48 | typedef long _StateIdT; |
49 | _GLIBCXX17_INLINE constexpr _StateIdT _S_invalid_state_id = -1; |
50 | |
51 | template<typename _CharT> |
52 | using _Matcher = std::function<bool (_CharT)>; |
53 | |
54 | /// Operation codes that define the type of transitions within the base NFA |
55 | /// that represents the regular expression. |
56 | enum _Opcode : int |
57 | { |
58 | _S_opcode_unknown, |
59 | _S_opcode_alternative, |
60 | _S_opcode_repeat, |
61 | _S_opcode_backref, |
62 | _S_opcode_line_begin_assertion, |
63 | _S_opcode_line_end_assertion, |
64 | _S_opcode_word_boundary, |
65 | _S_opcode_subexpr_lookahead, |
66 | _S_opcode_subexpr_begin, |
67 | _S_opcode_subexpr_end, |
68 | _S_opcode_dummy, |
69 | _S_opcode_match, |
70 | _S_opcode_accept, |
71 | }; |
72 | |
73 | struct _State_base |
74 | { |
75 | protected: |
76 | _Opcode _M_opcode; // type of outgoing transition |
77 | |
78 | public: |
79 | _StateIdT _M_next; // outgoing transition |
80 | union // Since they are mutually exclusive. |
81 | { |
82 | size_t _M_subexpr; // for _S_opcode_subexpr_* |
83 | size_t _M_backref_index; // for _S_opcode_backref |
84 | struct |
85 | { |
86 | // for _S_opcode_alternative, _S_opcode_repeat and |
87 | // _S_opcode_subexpr_lookahead |
88 | _StateIdT _M_alt; |
89 | // for _S_opcode_word_boundary or _S_opcode_subexpr_lookahead or |
90 | // quantifiers (ungreedy if set true) |
91 | bool _M_neg; |
92 | }; |
93 | // For _S_opcode_match |
94 | __gnu_cxx::__aligned_membuf<_Matcher<char>> _M_matcher_storage; |
95 | }; |
96 | |
97 | protected: |
98 | explicit _State_base(_Opcode __opcode) noexcept |
99 | : _M_opcode(__opcode), _M_next(_S_invalid_state_id) |
100 | { } |
101 | |
102 | public: |
103 | bool |
104 | _M_has_alt() const noexcept |
105 | { |
106 | return _M_opcode == _S_opcode_alternative |
107 | || _M_opcode == _S_opcode_repeat |
108 | || _M_opcode == _S_opcode_subexpr_lookahead; |
109 | } |
110 | |
111 | #ifdef _GLIBCXX_DEBUG |
112 | std::ostream& |
113 | _M_print(std::ostream& __ostr) const; |
114 | |
115 | // Prints graphviz dot commands for state. |
116 | std::ostream& |
117 | _M_dot(std::ostream& __ostr, _StateIdT __id) const; |
118 | #endif |
119 | }; |
120 | |
121 | template<typename _Char_type> |
122 | struct _State : _State_base |
123 | { |
124 | typedef _Matcher<_Char_type> _MatcherT; |
125 | static_assert(sizeof(_MatcherT) == sizeof(_Matcher<char>), |
126 | "std::function<bool(T)> has the same size as " |
127 | "std::function<bool(char)>" ); |
128 | static_assert(alignof(_MatcherT) == alignof(_Matcher<char>), |
129 | "std::function<bool(T)> has the same alignment as " |
130 | "std::function<bool(char)>" ); |
131 | |
132 | explicit |
133 | _State(_Opcode __opcode) noexcept : _State_base(__opcode) |
134 | { |
135 | if (_M_opcode() == _S_opcode_match) |
136 | new (this->_M_matcher_storage._M_addr()) _MatcherT(); |
137 | } |
138 | |
139 | _State(const _State& __rhs) : _State_base(__rhs) |
140 | { |
141 | if (__rhs._M_opcode() == _S_opcode_match) |
142 | new (this->_M_matcher_storage._M_addr()) |
143 | _MatcherT(__rhs._M_get_matcher()); |
144 | } |
145 | |
146 | _State(_State&& __rhs) noexcept : _State_base(__rhs) |
147 | { |
148 | if (__rhs._M_opcode() == _S_opcode_match) |
149 | new (this->_M_matcher_storage._M_addr()) |
150 | _MatcherT(std::move(__rhs._M_get_matcher())); |
151 | } |
152 | |
153 | _State& |
154 | operator=(const _State&) = delete; |
155 | |
156 | ~_State() |
157 | { |
158 | if (_M_opcode() == _S_opcode_match) |
159 | _M_get_matcher().~_MatcherT(); |
160 | } |
161 | |
162 | // Since correct ctor and dtor rely on _M_opcode, it's better not to |
163 | // change it over time. |
164 | _Opcode |
165 | _M_opcode() const noexcept |
166 | { return _State_base::_M_opcode; } |
167 | |
168 | bool |
169 | _M_matches(_Char_type __char) const |
170 | { return _M_get_matcher()(__char); } |
171 | |
172 | _MatcherT& |
173 | _M_get_matcher() noexcept |
174 | { return *static_cast<_MatcherT*>(this->_M_matcher_storage._M_addr()); } |
175 | |
176 | const _MatcherT& |
177 | _M_get_matcher() const noexcept |
178 | { |
179 | return *static_cast<const _MatcherT*>( |
180 | this->_M_matcher_storage._M_addr()); |
181 | } |
182 | }; |
183 | |
184 | struct _NFA_base |
185 | { |
186 | typedef regex_constants::syntax_option_type _FlagT; |
187 | |
188 | explicit |
189 | _NFA_base(_FlagT __f) noexcept |
190 | : _M_flags(__f), _M_start_state(0), _M_subexpr_count(0), |
191 | _M_has_backref(false) |
192 | { } |
193 | |
194 | _NFA_base(_NFA_base&&) = default; |
195 | |
196 | protected: |
197 | ~_NFA_base() = default; |
198 | |
199 | public: |
200 | _FlagT |
201 | _M_options() const noexcept |
202 | { return _M_flags; } |
203 | |
204 | _StateIdT |
205 | _M_start() const noexcept |
206 | { return _M_start_state; } |
207 | |
208 | size_t |
209 | _M_sub_count() const noexcept |
210 | { return _M_subexpr_count; } |
211 | |
212 | _GLIBCXX_STD_C::vector<size_t> _M_paren_stack; |
213 | _FlagT _M_flags; |
214 | _StateIdT _M_start_state; |
215 | size_t _M_subexpr_count; |
216 | bool _M_has_backref; |
217 | }; |
218 | |
219 | template<typename _TraitsT> |
220 | struct _NFA |
221 | : _NFA_base, _GLIBCXX_STD_C::vector<_State<typename _TraitsT::char_type>> |
222 | { |
223 | typedef typename _TraitsT::char_type _Char_type; |
224 | typedef _State<_Char_type> _StateT; |
225 | typedef _Matcher<_Char_type> _MatcherT; |
226 | |
227 | _NFA(const typename _TraitsT::locale_type& __loc, _FlagT __flags) |
228 | : _NFA_base(__flags) |
229 | { _M_traits.imbue(__loc); } |
230 | |
231 | // for performance reasons _NFA objects should only be moved not copied |
232 | _NFA(const _NFA&) = delete; |
233 | _NFA(_NFA&&) = default; |
234 | |
235 | _StateIdT |
236 | _M_insert_accept() |
237 | { |
238 | auto __ret = _M_insert_state(s: _StateT(_S_opcode_accept)); |
239 | return __ret; |
240 | } |
241 | |
242 | _StateIdT |
243 | _M_insert_alt(_StateIdT __next, _StateIdT __alt, |
244 | bool __neg __attribute__((__unused__))) |
245 | { |
246 | _StateT __tmp(_S_opcode_alternative); |
247 | // It labels every quantifier to make greedy comparison easier in BFS |
248 | // approach. |
249 | __tmp._M_next = __next; |
250 | __tmp._M_alt = __alt; |
251 | return _M_insert_state(s: std::move(__tmp)); |
252 | } |
253 | |
254 | _StateIdT |
255 | _M_insert_repeat(_StateIdT __next, _StateIdT __alt, bool __neg) |
256 | { |
257 | _StateT __tmp(_S_opcode_repeat); |
258 | // It labels every quantifier to make greedy comparison easier in BFS |
259 | // approach. |
260 | __tmp._M_next = __next; |
261 | __tmp._M_alt = __alt; |
262 | __tmp._M_neg = __neg; |
263 | return _M_insert_state(s: std::move(__tmp)); |
264 | } |
265 | |
266 | _StateIdT |
267 | _M_insert_matcher(_MatcherT __m) |
268 | { |
269 | _StateT __tmp(_S_opcode_match); |
270 | __tmp._M_get_matcher() = std::move(__m); |
271 | return _M_insert_state(s: std::move(__tmp)); |
272 | } |
273 | |
274 | _StateIdT |
275 | _M_insert_subexpr_begin() |
276 | { |
277 | auto __id = this->_M_subexpr_count++; |
278 | this->_M_paren_stack.push_back(__id); |
279 | _StateT __tmp(_S_opcode_subexpr_begin); |
280 | __tmp._M_subexpr = __id; |
281 | return _M_insert_state(s: std::move(__tmp)); |
282 | } |
283 | |
284 | _StateIdT |
285 | _M_insert_subexpr_end() |
286 | { |
287 | _StateT __tmp(_S_opcode_subexpr_end); |
288 | __tmp._M_subexpr = this->_M_paren_stack.back(); |
289 | this->_M_paren_stack.pop_back(); |
290 | return _M_insert_state(s: std::move(__tmp)); |
291 | } |
292 | |
293 | _StateIdT |
294 | _M_insert_backref(size_t __index); |
295 | |
296 | _StateIdT |
297 | _M_insert_line_begin() |
298 | { return _M_insert_state(s: _StateT(_S_opcode_line_begin_assertion)); } |
299 | |
300 | _StateIdT |
301 | _M_insert_line_end() |
302 | { return _M_insert_state(s: _StateT(_S_opcode_line_end_assertion)); } |
303 | |
304 | _StateIdT |
305 | _M_insert_word_bound(bool __neg) |
306 | { |
307 | _StateT __tmp(_S_opcode_word_boundary); |
308 | __tmp._M_neg = __neg; |
309 | return _M_insert_state(s: std::move(__tmp)); |
310 | } |
311 | |
312 | _StateIdT |
313 | _M_insert_lookahead(_StateIdT __alt, bool __neg) |
314 | { |
315 | _StateT __tmp(_S_opcode_subexpr_lookahead); |
316 | __tmp._M_alt = __alt; |
317 | __tmp._M_neg = __neg; |
318 | return _M_insert_state(s: std::move(__tmp)); |
319 | } |
320 | |
321 | _StateIdT |
322 | _M_insert_dummy() |
323 | { return _M_insert_state(s: _StateT(_S_opcode_dummy)); } |
324 | |
325 | _StateIdT |
326 | _M_insert_state(_StateT __s) |
327 | { |
328 | this->push_back(std::move(__s)); |
329 | if (this->size() > _GLIBCXX_REGEX_STATE_LIMIT) |
330 | __throw_regex_error( |
331 | ecode: regex_constants::error_space, |
332 | what: "Number of NFA states exceeds limit. Please use shorter regex " |
333 | "string, or use smaller brace expression, or make " |
334 | "_GLIBCXX_REGEX_STATE_LIMIT larger." ); |
335 | return this->size() - 1; |
336 | } |
337 | |
338 | // Eliminate dummy node in this NFA to make it compact. |
339 | void |
340 | _M_eliminate_dummy(); |
341 | |
342 | #ifdef _GLIBCXX_DEBUG |
343 | std::ostream& |
344 | _M_dot(std::ostream& __ostr) const; |
345 | #endif |
346 | public: |
347 | _TraitsT _M_traits; |
348 | }; |
349 | |
350 | /// Describes a sequence of one or more %_State, its current start |
351 | /// and end(s). This structure contains fragments of an NFA during |
352 | /// construction. |
353 | template<typename _TraitsT> |
354 | class _StateSeq |
355 | { |
356 | public: |
357 | typedef _NFA<_TraitsT> _RegexT; |
358 | |
359 | public: |
360 | _StateSeq(_RegexT& __nfa, _StateIdT __s) |
361 | : _M_nfa(__nfa), _M_start(__s), _M_end(__s) |
362 | { } |
363 | |
364 | _StateSeq(_RegexT& __nfa, _StateIdT __s, _StateIdT __end) |
365 | : _M_nfa(__nfa), _M_start(__s), _M_end(__end) |
366 | { } |
367 | |
368 | // Append a state on *this and change *this to the new sequence. |
369 | void |
370 | _M_append(_StateIdT __id) |
371 | { |
372 | _M_nfa[_M_end]._M_next = __id; |
373 | _M_end = __id; |
374 | } |
375 | |
376 | // Append a sequence on *this and change *this to the new sequence. |
377 | void |
378 | _M_append(const _StateSeq& __s) |
379 | { |
380 | _M_nfa[_M_end]._M_next = __s._M_start; |
381 | _M_end = __s._M_end; |
382 | } |
383 | |
384 | // Clones an entire sequence. |
385 | _StateSeq |
386 | _M_clone(); |
387 | |
388 | public: |
389 | _RegexT& _M_nfa; |
390 | _StateIdT _M_start; |
391 | _StateIdT _M_end; |
392 | }; |
393 | |
394 | ///@} regex-detail |
395 | } // namespace __detail |
396 | |
397 | _GLIBCXX_END_NAMESPACE_VERSION |
398 | } // namespace std |
399 | |
400 | #include <bits/regex_automaton.tcc> |
401 | |