1 // class template regex -*- C++ -*-
3 // Copyright (C) 2013-2018 Free Software Foundation, Inc.
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)
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.
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.
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/>.
26 * @file bits/regex_compiler.tcc
27 * This is an internal header file, included by other library headers.
28 * Do not attempt to use it directly. @headername{regex}
31 // FIXME make comments doxygen format.
34 // This compiler refers to "Regular Expression Matching Can Be Simple And Fast"
35 // (http://swtch.com/~rsc/regexp/regexp1.html),
36 // but doesn't strictly follow it.
38 // When compiling, states are *chained* instead of tree- or graph-constructed.
39 // It's more like structured programs: there's if statement and loop statement.
41 // For alternative structure (say "a|b"), aka "if statement", two branches
42 // should be constructed. However, these two shall merge to an "end_tag" at
43 // the end of this operator:
47 // => begin_tag end_tag =>
51 // This is the difference between this implementation and that in Russ's
54 // That's why we introduced dummy node here ------ "end_tag" is a dummy node.
55 // All dummy nodes will be eliminated at the end of compilation.
58 namespace std _GLIBCXX_VISIBILITY(default)
60 _GLIBCXX_BEGIN_NAMESPACE_VERSION
64 template<typename _TraitsT>
66 _Compiler(_IterT __b, _IterT __e,
67 const typename _TraitsT::locale_type& __loc, _FlagT __flags)
69 & (regex_constants::ECMAScript
70 | regex_constants::basic
71 | regex_constants::extended
72 | regex_constants::grep
73 | regex_constants::egrep
74 | regex_constants::awk))
76 : __flags | regex_constants::ECMAScript),
77 _M_scanner(__b, __e, _M_flags, __loc),
78 _M_nfa(make_shared<_RegexT>(__loc, _M_flags)),
79 _M_traits(_M_nfa->_M_traits),
80 _M_ctype(std::use_facet<_CtypeT>(__loc))
82 _StateSeqT __r(*_M_nfa, _M_nfa->_M_start());
83 __r._M_append(_M_nfa->_M_insert_subexpr_begin());
84 this->_M_disjunction();
85 if (!_M_match_token(_ScannerT::_S_token_eof))
86 __throw_regex_error(regex_constants::error_paren);
87 __r._M_append(_M_pop());
88 __glibcxx_assert(_M_stack.empty());
89 __r._M_append(_M_nfa->_M_insert_subexpr_end());
90 __r._M_append(_M_nfa->_M_insert_accept());
91 _M_nfa->_M_eliminate_dummy();
94 template<typename _TraitsT>
99 this->_M_alternative();
100 while (_M_match_token(_ScannerT::_S_token_or))
102 _StateSeqT __alt1 = _M_pop();
103 this->_M_alternative();
104 _StateSeqT __alt2 = _M_pop();
105 auto __end = _M_nfa->_M_insert_dummy();
106 __alt1._M_append(__end);
107 __alt2._M_append(__end);
108 // __alt2 is state._M_next, __alt1 is state._M_alt. The executor
109 // executes _M_alt before _M_next, as well as executing left
110 // alternative before right one.
111 _M_stack.push(_StateSeqT(*_M_nfa,
112 _M_nfa->_M_insert_alt(
113 __alt2._M_start, __alt1._M_start, false),
118 template<typename _TraitsT>
120 _Compiler<_TraitsT>::
125 _StateSeqT __re = _M_pop();
126 this->_M_alternative();
127 __re._M_append(_M_pop());
131 _M_stack.push(_StateSeqT(*_M_nfa, _M_nfa->_M_insert_dummy()));
134 template<typename _TraitsT>
136 _Compiler<_TraitsT>::
139 if (this->_M_assertion())
143 while (this->_M_quantifier());
149 template<typename _TraitsT>
151 _Compiler<_TraitsT>::
154 if (_M_match_token(_ScannerT::_S_token_line_begin))
155 _M_stack.push(_StateSeqT(*_M_nfa, _M_nfa->_M_insert_line_begin()));
156 else if (_M_match_token(_ScannerT::_S_token_line_end))
157 _M_stack.push(_StateSeqT(*_M_nfa, _M_nfa->_M_insert_line_end()));
158 else if (_M_match_token(_ScannerT::_S_token_word_bound))
159 // _M_value[0] == 'n' means it's negative, say "not word boundary".
160 _M_stack.push(_StateSeqT(*_M_nfa, _M_nfa->
161 _M_insert_word_bound(_M_value[0] == 'n')));
162 else if (_M_match_token(_ScannerT::_S_token_subexpr_lookahead_begin))
164 auto __neg = _M_value[0] == 'n';
165 this->_M_disjunction();
166 if (!_M_match_token(_ScannerT::_S_token_subexpr_end))
167 __throw_regex_error(regex_constants::error_paren,
168 "Parenthesis is not closed.");
169 auto __tmp = _M_pop();
170 __tmp._M_append(_M_nfa->_M_insert_accept());
174 _M_nfa->_M_insert_lookahead(__tmp._M_start, __neg)));
181 template<typename _TraitsT>
183 _Compiler<_TraitsT>::
186 bool __neg = (_M_flags & regex_constants::ECMAScript);
187 auto __init = [this, &__neg]()
189 if (_M_stack.empty())
190 __throw_regex_error(regex_constants::error_badrepeat,
191 "Nothing to repeat before a quantifier.");
192 __neg = __neg && _M_match_token(_ScannerT::_S_token_opt);
194 if (_M_match_token(_ScannerT::_S_token_closure0))
198 _StateSeqT __r(*_M_nfa,
199 _M_nfa->_M_insert_repeat(_S_invalid_state_id,
200 __e._M_start, __neg));
204 else if (_M_match_token(_ScannerT::_S_token_closure1))
208 __e._M_append(_M_nfa->_M_insert_repeat(_S_invalid_state_id,
209 __e._M_start, __neg));
212 else if (_M_match_token(_ScannerT::_S_token_opt))
216 auto __end = _M_nfa->_M_insert_dummy();
217 _StateSeqT __r(*_M_nfa,
218 _M_nfa->_M_insert_repeat(_S_invalid_state_id,
219 __e._M_start, __neg));
220 __e._M_append(__end);
221 __r._M_append(__end);
224 else if (_M_match_token(_ScannerT::_S_token_interval_begin))
226 if (_M_stack.empty())
227 __throw_regex_error(regex_constants::error_badrepeat,
228 "Nothing to repeat before a quantifier.");
229 if (!_M_match_token(_ScannerT::_S_token_dup_count))
230 __throw_regex_error(regex_constants::error_badbrace,
231 "Unexpected token in brace expression.");
232 _StateSeqT __r(_M_pop());
233 _StateSeqT __e(*_M_nfa, _M_nfa->_M_insert_dummy());
234 long __min_rep = _M_cur_int_value(10);
239 if (_M_match_token(_ScannerT::_S_token_comma))
240 if (_M_match_token(_ScannerT::_S_token_dup_count)) // {3,7}
241 __n = _M_cur_int_value(10) - __min_rep;
246 if (!_M_match_token(_ScannerT::_S_token_interval_end))
247 __throw_regex_error(regex_constants::error_brace,
248 "Unexpected end of brace expression.");
250 __neg = __neg && _M_match_token(_ScannerT::_S_token_opt);
252 for (long __i = 0; __i < __min_rep; ++__i)
253 __e._M_append(__r._M_clone());
257 auto __tmp = __r._M_clone();
258 _StateSeqT __s(*_M_nfa,
259 _M_nfa->_M_insert_repeat(_S_invalid_state_id,
260 __tmp._M_start, __neg));
261 __tmp._M_append(__s);
267 __throw_regex_error(regex_constants::error_badbrace,
268 "Invalid range in brace expression.");
269 auto __end = _M_nfa->_M_insert_dummy();
270 // _M_alt is the "match more" branch, and _M_next is the
271 // "match less" one. Switch _M_alt and _M_next of all created
272 // nodes. This is a hack but IMO works well.
273 std::stack<_StateIdT> __stack;
274 for (long __i = 0; __i < __n; ++__i)
276 auto __tmp = __r._M_clone();
277 auto __alt = _M_nfa->_M_insert_repeat(__tmp._M_start,
280 __e._M_append(_StateSeqT(*_M_nfa, __alt, __tmp._M_end));
282 __e._M_append(__end);
283 while (!__stack.empty())
285 auto& __tmp = (*_M_nfa)[__stack.top()];
287 std::swap(__tmp._M_next, __tmp._M_alt);
297 #define __INSERT_REGEX_MATCHER(__func, ...)\
299 if (!(_M_flags & regex_constants::icase))\
300 if (!(_M_flags & regex_constants::collate))\
301 __func<false, false>(__VA_ARGS__);\
303 __func<false, true>(__VA_ARGS__);\
305 if (!(_M_flags & regex_constants::collate))\
306 __func<true, false>(__VA_ARGS__);\
308 __func<true, true>(__VA_ARGS__);\
311 template<typename _TraitsT>
313 _Compiler<_TraitsT>::
316 if (_M_match_token(_ScannerT::_S_token_anychar))
318 if (!(_M_flags & regex_constants::ECMAScript))
319 __INSERT_REGEX_MATCHER(_M_insert_any_matcher_posix);
321 __INSERT_REGEX_MATCHER(_M_insert_any_matcher_ecma);
323 else if (_M_try_char())
324 __INSERT_REGEX_MATCHER(_M_insert_char_matcher);
325 else if (_M_match_token(_ScannerT::_S_token_backref))
326 _M_stack.push(_StateSeqT(*_M_nfa, _M_nfa->
327 _M_insert_backref(_M_cur_int_value(10))));
328 else if (_M_match_token(_ScannerT::_S_token_quoted_class))
329 __INSERT_REGEX_MATCHER(_M_insert_character_class_matcher);
330 else if (_M_match_token(_ScannerT::_S_token_subexpr_no_group_begin))
332 _StateSeqT __r(*_M_nfa, _M_nfa->_M_insert_dummy());
333 this->_M_disjunction();
334 if (!_M_match_token(_ScannerT::_S_token_subexpr_end))
335 __throw_regex_error(regex_constants::error_paren,
336 "Parenthesis is not closed.");
337 __r._M_append(_M_pop());
340 else if (_M_match_token(_ScannerT::_S_token_subexpr_begin))
342 _StateSeqT __r(*_M_nfa, _M_nfa->_M_insert_subexpr_begin());
343 this->_M_disjunction();
344 if (!_M_match_token(_ScannerT::_S_token_subexpr_end))
345 __throw_regex_error(regex_constants::error_paren,
346 "Parenthesis is not closed.");
347 __r._M_append(_M_pop());
348 __r._M_append(_M_nfa->_M_insert_subexpr_end());
351 else if (!_M_bracket_expression())
356 template<typename _TraitsT>
358 _Compiler<_TraitsT>::
359 _M_bracket_expression()
362 _M_match_token(_ScannerT::_S_token_bracket_neg_begin);
363 if (!(__neg || _M_match_token(_ScannerT::_S_token_bracket_begin)))
365 __INSERT_REGEX_MATCHER(_M_insert_bracket_matcher, __neg);
368 #undef __INSERT_REGEX_MATCHER
370 template<typename _TraitsT>
371 template<bool __icase, bool __collate>
373 _Compiler<_TraitsT>::
374 _M_insert_any_matcher_ecma()
376 _M_stack.push(_StateSeqT(*_M_nfa,
377 _M_nfa->_M_insert_matcher
378 (_AnyMatcher<_TraitsT, true, __icase, __collate>
382 template<typename _TraitsT>
383 template<bool __icase, bool __collate>
385 _Compiler<_TraitsT>::
386 _M_insert_any_matcher_posix()
388 _M_stack.push(_StateSeqT(*_M_nfa,
389 _M_nfa->_M_insert_matcher
390 (_AnyMatcher<_TraitsT, false, __icase, __collate>
394 template<typename _TraitsT>
395 template<bool __icase, bool __collate>
397 _Compiler<_TraitsT>::
398 _M_insert_char_matcher()
400 _M_stack.push(_StateSeqT(*_M_nfa,
401 _M_nfa->_M_insert_matcher
402 (_CharMatcher<_TraitsT, __icase, __collate>
403 (_M_value[0], _M_traits))));
406 template<typename _TraitsT>
407 template<bool __icase, bool __collate>
409 _Compiler<_TraitsT>::
410 _M_insert_character_class_matcher()
412 __glibcxx_assert(_M_value.size() == 1);
413 _BracketMatcher<_TraitsT, __icase, __collate> __matcher
414 (_M_ctype.is(_CtypeT::upper, _M_value[0]), _M_traits);
415 __matcher._M_add_character_class(_M_value, false);
416 __matcher._M_ready();
417 _M_stack.push(_StateSeqT(*_M_nfa,
418 _M_nfa->_M_insert_matcher(std::move(__matcher))));
421 template<typename _TraitsT>
422 template<bool __icase, bool __collate>
424 _Compiler<_TraitsT>::
425 _M_insert_bracket_matcher(bool __neg)
427 _BracketMatcher<_TraitsT, __icase, __collate> __matcher(__neg, _M_traits);
428 pair<bool, _CharT> __last_char; // Optional<_CharT>
429 __last_char.first = false;
430 if (!(_M_flags & regex_constants::ECMAScript))
434 __last_char.first = true;
435 __last_char.second = _M_value[0];
437 else if (_M_match_token(_ScannerT::_S_token_bracket_dash))
439 __last_char.first = true;
440 __last_char.second = '-';
443 while (_M_expression_term(__last_char, __matcher));
444 if (__last_char.first)
445 __matcher._M_add_char(__last_char.second);
446 __matcher._M_ready();
447 _M_stack.push(_StateSeqT(
449 _M_nfa->_M_insert_matcher(std::move(__matcher))));
452 template<typename _TraitsT>
453 template<bool __icase, bool __collate>
455 _Compiler<_TraitsT>::
456 _M_expression_term(pair<bool, _CharT>& __last_char,
457 _BracketMatcher<_TraitsT, __icase, __collate>& __matcher)
459 if (_M_match_token(_ScannerT::_S_token_bracket_end))
462 const auto __push_char = [&](_CharT __ch)
464 if (__last_char.first)
465 __matcher._M_add_char(__last_char.second);
467 __last_char.first = true;
468 __last_char.second = __ch;
470 const auto __flush = [&]
472 if (__last_char.first)
474 __matcher._M_add_char(__last_char.second);
475 __last_char.first = false;
479 if (_M_match_token(_ScannerT::_S_token_collsymbol))
481 auto __symbol = __matcher._M_add_collate_element(_M_value);
482 if (__symbol.size() == 1)
483 __push_char(__symbol[0]);
487 else if (_M_match_token(_ScannerT::_S_token_equiv_class_name))
490 __matcher._M_add_equivalence_class(_M_value);
492 else if (_M_match_token(_ScannerT::_S_token_char_class_name))
495 __matcher._M_add_character_class(_M_value, false);
497 else if (_M_try_char())
498 __push_char(_M_value[0]);
499 // POSIX doesn't allow '-' as a start-range char (say [a-z--0]),
500 // except when the '-' is the first or last character in the bracket
501 // expression ([--0]). ECMAScript treats all '-' after a range as a
502 // normal character. Also see above, where _M_expression_term gets called.
504 // As a result, POSIX rejects [-----], but ECMAScript doesn't.
505 // Boost (1.57.0) always uses POSIX style even in its ECMAScript syntax.
506 // Clang (3.5) always uses ECMAScript style even in its POSIX syntax.
508 // It turns out that no one reads BNFs ;)
509 else if (_M_match_token(_ScannerT::_S_token_bracket_dash))
511 if (!__last_char.first)
513 if (!(_M_flags & regex_constants::ECMAScript))
515 if (_M_match_token(_ScannerT::_S_token_bracket_end))
521 regex_constants::error_range,
522 "Unexpected dash in bracket expression. For POSIX syntax, "
523 "a dash is not treated literally only when it is at "
524 "beginning or end.");
532 __matcher._M_make_range(__last_char.second, _M_value[0]);
533 __last_char.first = false;
535 else if (_M_match_token(_ScannerT::_S_token_bracket_dash))
537 __matcher._M_make_range(__last_char.second, '-');
538 __last_char.first = false;
542 if (_M_scanner._M_get_token()
543 != _ScannerT::_S_token_bracket_end)
545 regex_constants::error_range,
546 "Character is expected after a dash.");
551 else if (_M_match_token(_ScannerT::_S_token_quoted_class))
554 __matcher._M_add_character_class(_M_value,
555 _M_ctype.is(_CtypeT::upper,
559 __throw_regex_error(regex_constants::error_brack,
560 "Unexpected character in bracket expression.");
565 template<typename _TraitsT>
567 _Compiler<_TraitsT>::
570 bool __is_char = false;
571 if (_M_match_token(_ScannerT::_S_token_oct_num))
574 _M_value.assign(1, _M_cur_int_value(8));
576 else if (_M_match_token(_ScannerT::_S_token_hex_num))
579 _M_value.assign(1, _M_cur_int_value(16));
581 else if (_M_match_token(_ScannerT::_S_token_ord_char))
586 template<typename _TraitsT>
588 _Compiler<_TraitsT>::
589 _M_match_token(_TokenT token)
591 if (token == _M_scanner._M_get_token())
593 _M_value = _M_scanner._M_get_value();
594 _M_scanner._M_advance();
600 template<typename _TraitsT>
602 _Compiler<_TraitsT>::
603 _M_cur_int_value(int __radix)
606 for (typename _StringT::size_type __i = 0;
607 __i < _M_value.length(); ++__i)
608 __v =__v * __radix + _M_traits.value(_M_value[__i], __radix);
612 template<typename _TraitsT, bool __icase, bool __collate>
614 _BracketMatcher<_TraitsT, __icase, __collate>::
615 _M_apply(_CharT __ch, false_type) const
619 if (std::binary_search(_M_char_set.begin(), _M_char_set.end(),
620 _M_translator._M_translate(__ch)))
622 auto __s = _M_translator._M_transform(__ch);
623 for (auto& __it : _M_range_set)
624 if (_M_translator._M_match_range(__it.first, __it.second, __s))
626 if (_M_traits.isctype(__ch, _M_class_set))
628 if (std::find(_M_equiv_set.begin(), _M_equiv_set.end(),
629 _M_traits.transform_primary(&__ch, &__ch+1))
630 != _M_equiv_set.end())
632 for (auto& __it : _M_neg_class_set)
633 if (!_M_traits.isctype(__ch, __it))
636 }() ^ _M_is_non_matching;
638 } // namespace __detail
640 _GLIBCXX_END_NAMESPACE_VERSION