1 | // class template regex -*- C++ -*- |
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2 | |

3 | // Copyright (C) 2013-2018 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 | static const _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) |

99 | : _M_opcode(__opcode), _M_next(_S_invalid_state_id) |

100 | { } |

101 | |

102 | public: |

103 | bool |

104 | _M_has_alt() |

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) : _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) : _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 |

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() |

174 | { return *static_cast<_MatcherT*>(this->_M_matcher_storage._M_addr()); } |

175 | |

176 | const _MatcherT& |

177 | _M_get_matcher() const |

178 | { |

179 | return *static_cast<const _MatcherT*>( |

180 | this->_M_matcher_storage._M_addr()); |

181 | } |

182 | }; |

183 | |

184 | struct _NFA_base |

185 | { |

186 | typedef size_t _SizeT; |

187 | typedef regex_constants::syntax_option_type _FlagT; |

188 | |

189 | explicit |

190 | _NFA_base(_FlagT __f) |

191 | : _M_flags(__f), _M_start_state(0), _M_subexpr_count(0), |

192 | _M_has_backref(false) |

193 | { } |

194 | |

195 | _NFA_base(_NFA_base&&) = default; |

196 | |

197 | protected: |

198 | ~_NFA_base() = default; |

199 | |

200 | public: |

201 | _FlagT |

202 | _M_options() const |

203 | { return _M_flags; } |

204 | |

205 | _StateIdT |

206 | _M_start() const |

207 | { return _M_start_state; } |

208 | |

209 | _SizeT |

210 | _M_sub_count() const |

211 | { return _M_subexpr_count; } |

212 | |

213 | std::vector<size_t> _M_paren_stack; |

214 | _FlagT _M_flags; |

215 | _StateIdT _M_start_state; |

216 | _SizeT _M_subexpr_count; |

217 | bool _M_has_backref; |

218 | }; |

219 | |

220 | template<typename _TraitsT> |

221 | struct _NFA |

222 | : _NFA_base, std::vector<_State<typename _TraitsT::char_type>> |

223 | { |

224 | typedef typename _TraitsT::char_type _Char_type; |

225 | typedef _State<_Char_type> _StateT; |

226 | typedef _Matcher<_Char_type> _MatcherT; |

227 | |

228 | _NFA(const typename _TraitsT::locale_type& __loc, _FlagT __flags) |

229 | : _NFA_base(__flags) |

230 | { _M_traits.imbue(__loc); } |

231 | |

232 | // for performance reasons _NFA objects should only be moved not copied |

233 | _NFA(const _NFA&) = delete; |

234 | _NFA(_NFA&&) = default; |

235 | |

236 | _StateIdT |

237 | _M_insert_accept() |

238 | { |

239 | auto __ret = _M_insert_state(_StateT(_S_opcode_accept)); |

240 | return __ret; |

241 | } |

242 | |

243 | _StateIdT |

244 | _M_insert_alt(_StateIdT __next, _StateIdT __alt, |

245 | bool __neg __attribute__((__unused__))) |

246 | { |

247 | _StateT __tmp(_S_opcode_alternative); |

248 | // It labels every quantifier to make greedy comparison easier in BFS |

249 | // approach. |

250 | __tmp._M_next = __next; |

251 | __tmp._M_alt = __alt; |

252 | return _M_insert_state(std::move(__tmp)); |

253 | } |

254 | |

255 | _StateIdT |

256 | _M_insert_repeat(_StateIdT __next, _StateIdT __alt, bool __neg) |

257 | { |

258 | _StateT __tmp(_S_opcode_repeat); |

259 | // It labels every quantifier to make greedy comparison easier in BFS |

260 | // approach. |

261 | __tmp._M_next = __next; |

262 | __tmp._M_alt = __alt; |

263 | __tmp._M_neg = __neg; |

264 | return _M_insert_state(std::move(__tmp)); |

265 | } |

266 | |

267 | _StateIdT |

268 | _M_insert_matcher(_MatcherT __m) |

269 | { |

270 | _StateT __tmp(_S_opcode_match); |

271 | __tmp._M_get_matcher() = std::move(__m); |

272 | return _M_insert_state(std::move(__tmp)); |

273 | } |

274 | |

275 | _StateIdT |

276 | _M_insert_subexpr_begin() |

277 | { |

278 | auto __id = this->_M_subexpr_count++; |

279 | this->_M_paren_stack.push_back(__id); |

280 | _StateT __tmp(_S_opcode_subexpr_begin); |

281 | __tmp._M_subexpr = __id; |

282 | return _M_insert_state(std::move(__tmp)); |

283 | } |

284 | |

285 | _StateIdT |

286 | _M_insert_subexpr_end() |

287 | { |

288 | _StateT __tmp(_S_opcode_subexpr_end); |

289 | __tmp._M_subexpr = this->_M_paren_stack.back(); |

290 | this->_M_paren_stack.pop_back(); |

291 | return _M_insert_state(std::move(__tmp)); |

292 | } |

293 | |

294 | _StateIdT |

295 | _M_insert_backref(size_t __index); |

296 | |

297 | _StateIdT |

298 | _M_insert_line_begin() |

299 | { return _M_insert_state(_StateT(_S_opcode_line_begin_assertion)); } |

300 | |

301 | _StateIdT |

302 | _M_insert_line_end() |

303 | { return _M_insert_state(_StateT(_S_opcode_line_end_assertion)); } |

304 | |

305 | _StateIdT |

306 | _M_insert_word_bound(bool __neg) |

307 | { |

308 | _StateT __tmp(_S_opcode_word_boundary); |

309 | __tmp._M_neg = __neg; |

310 | return _M_insert_state(std::move(__tmp)); |

311 | } |

312 | |

313 | _StateIdT |

314 | _M_insert_lookahead(_StateIdT __alt, bool __neg) |

315 | { |

316 | _StateT __tmp(_S_opcode_subexpr_lookahead); |

317 | __tmp._M_alt = __alt; |

318 | __tmp._M_neg = __neg; |

319 | return _M_insert_state(std::move(__tmp)); |

320 | } |

321 | |

322 | _StateIdT |

323 | _M_insert_dummy() |

324 | { return _M_insert_state(_StateT(_S_opcode_dummy)); } |

325 | |

326 | _StateIdT |

327 | _M_insert_state(_StateT __s) |

328 | { |

329 | this->push_back(std::move(__s)); |

330 | if (this->size() > _GLIBCXX_REGEX_STATE_LIMIT) |

331 | __throw_regex_error( |

332 | regex_constants::error_space, |

333 | "Number of NFA states exceeds limit. Please use shorter regex " |

334 | "string, or use smaller brace expression, or make " |

335 | "_GLIBCXX_REGEX_STATE_LIMIT larger."); |

336 | return this->size() - 1; |

337 | } |

338 | |

339 | // Eliminate dummy node in this NFA to make it compact. |

340 | void |

341 | _M_eliminate_dummy(); |

342 | |

343 | #ifdef _GLIBCXX_DEBUG |

344 | std::ostream& |

345 | _M_dot(std::ostream& __ostr) const; |

346 | #endif |

347 | public: |

348 | _TraitsT _M_traits; |

349 | }; |

350 | |

351 | /// Describes a sequence of one or more %_State, its current start |

352 | /// and end(s). This structure contains fragments of an NFA during |

353 | /// construction. |

354 | template<typename _TraitsT> |

355 | class _StateSeq |

356 | { |

357 | public: |

358 | typedef _NFA<_TraitsT> _RegexT; |

359 | |

360 | public: |

361 | _StateSeq(_RegexT& __nfa, _StateIdT __s) |

362 | : _M_nfa(__nfa), _M_start(__s), _M_end(__s) |

363 | { } |

364 | |

365 | _StateSeq(_RegexT& __nfa, _StateIdT __s, _StateIdT __end) |

366 | : _M_nfa(__nfa), _M_start(__s), _M_end(__end) |

367 | { } |

368 | |

369 | // Append a state on *this and change *this to the new sequence. |

370 | void |

371 | _M_append(_StateIdT __id) |

372 | { |

373 | _M_nfa[_M_end]._M_next = __id; |

374 | _M_end = __id; |

375 | } |

376 | |

377 | // Append a sequence on *this and change *this to the new sequence. |

378 | void |

379 | _M_append(const _StateSeq& __s) |

380 | { |

381 | _M_nfa[_M_end]._M_next = __s._M_start; |

382 | _M_end = __s._M_end; |

383 | } |

384 | |

385 | // Clones an entire sequence. |

386 | _StateSeq |

387 | _M_clone(); |

388 | |

389 | public: |

390 | _RegexT& _M_nfa; |

391 | _StateIdT _M_start; |

392 | _StateIdT _M_end; |

393 | }; |

394 | |

395 | //@} regex-detail |

396 | } // namespace __detail |

397 | |

398 | _GLIBCXX_END_NAMESPACE_VERSION |

399 | } // namespace std |

400 | |

401 | #include <bits/regex_automaton.tcc> |

402 |