| blob | 1555669393113acafc30dbb667d05df662f506cd |
1 // class template regex -*- C++ -*-
3 // Copyright (C) 2013-2015 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.
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/>.
25 /**
26 * @file bits/regex_scanner.tcc
27 * This is an internal header file, included by other library headers.
28 * Do not attempt to use it directly. @headername{regex}
29 */
31 // FIXME make comments doxygen format.
33 // N3376 specified 6 regex styles: ECMAScript, basic, extended, grep, egrep
34 // and awk
35 // 1) grep is basic except '\n' is treated as '|'
36 // 2) egrep is extended except '\n' is treated as '|'
37 // 3) awk is extended except special escaping rules, and there's no
38 // back-reference.
39 //
40 // References:
41 //
42 // ECMAScript: ECMA-262 15.10
43 //
44 // basic, extended:
45 // http://pubs.opengroup.org/onlinepubs/009695399/basedefs/xbd_chap09.html
46 //
47 // awk: http://pubs.opengroup.org/onlinepubs/000095399/utilities/awk.html
49 namespace std _GLIBCXX_VISIBILITY(default)
50 {
51 namespace __detail
52 {
53 _GLIBCXX_BEGIN_NAMESPACE_VERSION
55 template<typename _CharT>
56 _Scanner<_CharT>::
57 _Scanner(typename _Scanner::_IterT __begin,
58 typename _Scanner::_IterT __end,
59 _FlagT __flags, std::locale __loc)
60 : _ScannerBase(__flags),
61 _M_current(__begin), _M_end(__end),
62 _M_ctype(std::use_facet<_CtypeT>(__loc)),
63 _M_eat_escape(_M_is_ecma()
64 ? &_Scanner::_M_eat_escape_ecma
65 : &_Scanner::_M_eat_escape_posix)
66 { _M_advance(); }
68 template<typename _CharT>
69 void
70 _Scanner<_CharT>::
71 _M_advance()
72 {
73 if (_M_current == _M_end)
74 {
75 _M_token = _S_token_eof;
76 return;
77 }
79 if (_M_state == _S_state_normal)
80 _M_scan_normal();
81 else if (_M_state == _S_state_in_bracket)
82 _M_scan_in_bracket();
83 else if (_M_state == _S_state_in_brace)
84 _M_scan_in_brace();
85 else
86 {
87 _GLIBCXX_DEBUG_ASSERT(false);
88 }
89 }
91 // Differences between styles:
92 // 1) "\(", "\)", "\{" in basic. It's not escaping.
93 // 2) "(?:", "(?=", "(?!" in ECMAScript.
94 template<typename _CharT>
95 void
96 _Scanner<_CharT>::
97 _M_scan_normal()
98 {
99 auto __c = *_M_current++;
100 const char* __pos;
102 if (std::strchr(_M_spec_char, _M_ctype.narrow(__c, '\0')) == nullptr)
103 {
104 _M_token = _S_token_ord_char;
105 _M_value.assign(1, __c);
106 return;
107 }
108 if (__c == '\\')
109 {
110 if (_M_current == _M_end)
111 __throw_regex_error(regex_constants::error_escape);
113 if (!_M_is_basic()
114 || (*_M_current != '('
115 && *_M_current != ')'
116 && *_M_current != '{'))
117 {
118 (this->*_M_eat_escape)();
119 return;
120 }
121 __c = *_M_current++;
122 }
123 if (__c == '(')
124 {
125 if (_M_is_ecma() && *_M_current == '?')
126 {
127 if (++_M_current == _M_end)
128 __throw_regex_error(regex_constants::error_paren);
130 if (*_M_current == ':')
131 {
132 ++_M_current;
133 _M_token = _S_token_subexpr_no_group_begin;
134 }
135 else if (*_M_current == '=')
136 {
137 ++_M_current;
138 _M_token = _S_token_subexpr_lookahead_begin;
139 _M_value.assign(1, 'p');
140 }
141 else if (*_M_current == '!')
142 {
143 ++_M_current;
144 _M_token = _S_token_subexpr_lookahead_begin;
145 _M_value.assign(1, 'n');
146 }
147 else
148 __throw_regex_error(regex_constants::error_paren);
149 }
150 else if (_M_flags & regex_constants::nosubs)
151 _M_token = _S_token_subexpr_no_group_begin;
152 else
153 _M_token = _S_token_subexpr_begin;
154 }
155 else if (__c == ')')
156 _M_token = _S_token_subexpr_end;
157 else if (__c == '[')
158 {
159 _M_state = _S_state_in_bracket;
160 _M_at_bracket_start = true;
161 if (_M_current != _M_end && *_M_current == '^')
162 {
163 _M_token = _S_token_bracket_neg_begin;
164 ++_M_current;
165 }
166 else
167 _M_token = _S_token_bracket_begin;
168 }
169 else if (__c == '{')
170 {
171 _M_state = _S_state_in_brace;
172 _M_token = _S_token_interval_begin;
173 }
174 else if (((__pos = std::strchr(_M_spec_char, _M_ctype.narrow(__c, '\0')))
175 != nullptr
176 && *__pos != '\0'
177 && __c != ']'
178 && __c != '}')
179 || (_M_is_grep() && __c == '\n'))
180 {
181 auto __it = _M_token_tbl;
182 auto __narrowc = _M_ctype.narrow(__c, '\0');
183 for (; __it->first != '\0'; ++__it)
184 if (__it->first == __narrowc)
185 {
186 _M_token = __it->second;
187 return;
188 }
189 _GLIBCXX_DEBUG_ASSERT(false);
190 }
191 else
192 {
193 _M_token = _S_token_ord_char;
194 _M_value.assign(1, __c);
195 }
196 }
198 // Differences between styles:
199 // 1) different semantics of "[]" and "[^]".
200 // 2) Escaping in bracket expr.
201 template<typename _CharT>
202 void
203 _Scanner<_CharT>::
204 _M_scan_in_bracket()
205 {
206 if (_M_current == _M_end)
207 __throw_regex_error(regex_constants::error_brack);
209 auto __c = *_M_current++;
211 if (__c == '[')
212 {
213 if (_M_current == _M_end)
214 __throw_regex_error(regex_constants::error_brack);
216 if (*_M_current == '.')
217 {
218 _M_token = _S_token_collsymbol;
219 _M_eat_class(*_M_current++);
220 }
221 else if (*_M_current == ':')
222 {
223 _M_token = _S_token_char_class_name;
224 _M_eat_class(*_M_current++);
225 }
226 else if (*_M_current == '=')
227 {
228 _M_token = _S_token_equiv_class_name;
229 _M_eat_class(*_M_current++);
230 }
231 else
232 {
233 _M_token = _S_token_ord_char;
234 _M_value.assign(1, __c);
235 }
236 }
237 // In POSIX, when encountering "[]" or "[^]", the ']' is interpreted
238 // literally. So "[]]" and "[^]]" are valid regexes. See the testcases
239 // `*/empty_range.cc`.
240 else if (__c == ']' && (_M_is_ecma() || !_M_at_bracket_start))
241 {
242 _M_token = _S_token_bracket_end;
243 _M_state = _S_state_normal;
244 }
245 // ECMAScript and awk permits escaping in bracket.
246 else if (__c == '\\' && (_M_is_ecma() || _M_is_awk()))
247 (this->*_M_eat_escape)();
248 else
249 {
250 _M_token = _S_token_ord_char;
251 _M_value.assign(1, __c);
252 }
253 _M_at_bracket_start = false;
254 }
256 // Differences between styles:
257 // 1) "\}" in basic style.
258 template<typename _CharT>
259 void
260 _Scanner<_CharT>::
261 _M_scan_in_brace()
262 {
263 if (_M_current == _M_end)
264 __throw_regex_error(regex_constants::error_brace);
266 auto __c = *_M_current++;
268 if (_M_ctype.is(_CtypeT::digit, __c))
269 {
270 _M_token = _S_token_dup_count;
271 _M_value.assign(1, __c);
272 while (_M_current != _M_end
273 && _M_ctype.is(_CtypeT::digit, *_M_current))
274 _M_value += *_M_current++;
275 }
276 else if (__c == ',')
277 _M_token = _S_token_comma;
278 // basic use \}.
279 else if (_M_is_basic())
280 {
281 if (__c == '\\' && _M_current != _M_end && *_M_current == '}')
282 {
283 _M_state = _S_state_normal;
284 _M_token = _S_token_interval_end;
285 ++_M_current;
286 }
287 else
288 __throw_regex_error(regex_constants::error_badbrace);
289 }
290 else if (__c == '}')
291 {
292 _M_state = _S_state_normal;
293 _M_token = _S_token_interval_end;
294 }
295 else
296 __throw_regex_error(regex_constants::error_badbrace);
297 }
299 template<typename _CharT>
300 void
301 _Scanner<_CharT>::
302 _M_eat_escape_ecma()
303 {
304 if (_M_current == _M_end)
305 __throw_regex_error(regex_constants::error_escape);
307 auto __c = *_M_current++;
308 auto __pos = _M_find_escape(_M_ctype.narrow(__c, '\0'));
310 if (__pos != nullptr && (__c != 'b' || _M_state == _S_state_in_bracket))
311 {
312 _M_token = _S_token_ord_char;
313 _M_value.assign(1, *__pos);
314 }
315 else if (__c == 'b')
316 {
317 _M_token = _S_token_word_bound;
318 _M_value.assign(1, 'p');
319 }
320 else if (__c == 'B')
321 {
322 _M_token = _S_token_word_bound;
323 _M_value.assign(1, 'n');
324 }
325 // N3376 28.13
326 else if (__c == 'd'
327 || __c == 'D'
328 || __c == 's'
329 || __c == 'S'
330 || __c == 'w'
331 || __c == 'W')
332 {
333 _M_token = _S_token_quoted_class;
334 _M_value.assign(1, __c);
335 }
336 else if (__c == 'c')
337 {
338 if (_M_current == _M_end)
339 __throw_regex_error(regex_constants::error_escape);
340 _M_token = _S_token_ord_char;
341 _M_value.assign(1, *_M_current++);
342 }
343 else if (__c == 'x' || __c == 'u')
344 {
345 _M_value.erase();
346 for (int __i = 0; __i < (__c == 'x' ? 2 : 4); __i++)
347 {
348 if (_M_current == _M_end
349 || !_M_ctype.is(_CtypeT::xdigit, *_M_current))
350 __throw_regex_error(regex_constants::error_escape);
351 _M_value += *_M_current++;
352 }
353 _M_token = _S_token_hex_num;
354 }
355 // ECMAScript recognizes multi-digit back-references.
356 else if (_M_ctype.is(_CtypeT::digit, __c))
357 {
358 _M_value.assign(1, __c);
359 while (_M_current != _M_end
360 && _M_ctype.is(_CtypeT::digit, *_M_current))
361 _M_value += *_M_current++;
362 _M_token = _S_token_backref;
363 }
364 else
365 {
366 _M_token = _S_token_ord_char;
367 _M_value.assign(1, __c);
368 }
369 }
371 // Differences between styles:
372 // 1) Extended doesn't support backref, but basic does.
373 template<typename _CharT>
374 void
375 _Scanner<_CharT>::
376 _M_eat_escape_posix()
377 {
378 if (_M_current == _M_end)
379 __throw_regex_error(regex_constants::error_escape);
381 auto __c = *_M_current;
382 auto __pos = std::strchr(_M_spec_char, _M_ctype.narrow(__c, '\0'));
384 if (__pos != nullptr && *__pos != '\0')
385 {
386 _M_token = _S_token_ord_char;
387 _M_value.assign(1, __c);
388 }
389 // We MUST judge awk before handling backrefs. There's no backref in awk.
390 else if (_M_is_awk())
391 {
392 _M_eat_escape_awk();
393 return;
394 }
395 else if (_M_is_basic() && _M_ctype.is(_CtypeT::digit, __c) && __c != '0')
396 {
397 _M_token = _S_token_backref;
398 _M_value.assign(1, __c);
399 }
400 else
401 {
402 #ifdef __STRICT_ANSI__
403 // POSIX says it is undefined to escape ordinary characters
404 __throw_regex_error(regex_constants::error_escape);
405 #else
406 _M_token = _S_token_ord_char;
407 _M_value.assign(1, __c);
408 #endif
409 }
410 ++_M_current;
411 }
413 template<typename _CharT>
414 void
415 _Scanner<_CharT>::
416 _M_eat_escape_awk()
417 {
418 auto __c = *_M_current++;
419 auto __pos = _M_find_escape(_M_ctype.narrow(__c, '\0'));
421 if (__pos != nullptr)
422 {
423 _M_token = _S_token_ord_char;
424 _M_value.assign(1, *__pos);
425 }
426 // \ddd for oct representation
427 else if (_M_ctype.is(_CtypeT::digit, __c)
428 && __c != '8'
429 && __c != '9')
430 {
431 _M_value.assign(1, __c);
432 for (int __i = 0;
433 __i < 2
434 && _M_current != _M_end
435 && _M_ctype.is(_CtypeT::digit, *_M_current)
436 && *_M_current != '8'
437 && *_M_current != '9';
438 __i++)
439 _M_value += *_M_current++;
440 _M_token = _S_token_oct_num;
441 return;
442 }
443 else
444 __throw_regex_error(regex_constants::error_escape);
445 }
447 // Eats a character class or throws an exception.
448 // __ch could be ':', '.' or '=', _M_current is the char after ']' when
449 // returning.
450 template<typename _CharT>
451 void
452 _Scanner<_CharT>::
453 _M_eat_class(char __ch)
454 {
455 for (_M_value.clear(); _M_current != _M_end && *_M_current != __ch;)
456 _M_value += *_M_current++;
457 if (_M_current == _M_end
458 || *_M_current++ != __ch
459 || _M_current == _M_end // skip __ch
460 || *_M_current++ != ']') // skip ']'
461 {
462 if (__ch == ':')
463 __throw_regex_error(regex_constants::error_ctype);
464 else
465 __throw_regex_error(regex_constants::error_collate);
466 }
467 }
469 #ifdef _GLIBCXX_DEBUG
470 template<typename _CharT>
471 std::ostream&
472 _Scanner<_CharT>::
473 _M_print(std::ostream& ostr)
474 {
475 switch (_M_token)
476 {
477 case _S_token_anychar:
478 ostr << "any-character\n";
479 break;
480 case _S_token_backref:
481 ostr << "backref\n";
482 break;
483 case _S_token_bracket_begin:
484 ostr << "bracket-begin\n";
485 break;
486 case _S_token_bracket_neg_begin:
487 ostr << "bracket-neg-begin\n";
488 break;
489 case _S_token_bracket_end:
490 ostr << "bracket-end\n";
491 break;
492 case _S_token_char_class_name:
493 ostr << "char-class-name \"" << _M_value << "\"\n";
494 break;
495 case _S_token_closure0:
496 ostr << "closure0\n";
497 break;
498 case _S_token_closure1:
499 ostr << "closure1\n";
500 break;
501 case _S_token_collsymbol:
502 ostr << "collsymbol \"" << _M_value << "\"\n";
503 break;
504 case _S_token_comma:
505 ostr << "comma\n";
506 break;
507 case _S_token_dup_count:
508 ostr << "dup count: " << _M_value << "\n";
509 break;
510 case _S_token_eof:
511 ostr << "EOF\n";
512 break;
513 case _S_token_equiv_class_name:
514 ostr << "equiv-class-name \"" << _M_value << "\"\n";
515 break;
516 case _S_token_interval_begin:
517 ostr << "interval begin\n";
518 break;
519 case _S_token_interval_end:
520 ostr << "interval end\n";
521 break;
522 case _S_token_line_begin:
523 ostr << "line begin\n";
524 break;
525 case _S_token_line_end:
526 ostr << "line end\n";
527 break;
528 case _S_token_opt:
529 ostr << "opt\n";
530 break;
531 case _S_token_or:
532 ostr << "or\n";
533 break;
534 case _S_token_ord_char:
535 ostr << "ordinary character: \"" << _M_value << "\"\n";
536 break;
537 case _S_token_subexpr_begin:
538 ostr << "subexpr begin\n";
539 break;
540 case _S_token_subexpr_no_group_begin:
541 ostr << "no grouping subexpr begin\n";
542 break;
543 case _S_token_subexpr_lookahead_begin:
544 ostr << "lookahead subexpr begin\n";
545 break;
546 case _S_token_subexpr_end:
547 ostr << "subexpr end\n";
548 break;
549 case _S_token_unknown:
550 ostr << "-- unknown token --\n";
551 break;
552 case _S_token_oct_num:
553 ostr << "oct number " << _M_value << "\n";
554 break;
555 case _S_token_hex_num:
556 ostr << "hex number " << _M_value << "\n";
557 break;
558 case _S_token_quoted_class:
559 ostr << "quoted class " << "\\" << _M_value << "\n";
560 break;
561 default:
562 _GLIBCXX_DEBUG_ASSERT(false);
563 }
564 return ostr;
565 }
566 #endif
568 _GLIBCXX_END_NAMESPACE_VERSION
569 } // namespace __detail
570 } // namespace