| blob | 818e47b5670005ffb24be9598adf37ff3c7f1c99 |
1 // class template regex -*- C++ -*-
3 // Copyright (C) 2013-2014 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 _GLIBCXX_DEBUG_ASSERT(false);
87 }
89 // Differences between styles:
90 // 1) "\(", "\)", "\{" in basic. It's not escaping.
91 // 2) "(?:", "(?=", "(?!" in ECMAScript.
92 template<typename _CharT>
93 void
94 _Scanner<_CharT>::
95 _M_scan_normal()
96 {
97 auto __c = *_M_current++;
98 const char* __pos;
100 if (__c == '\\')
101 {
102 if (_M_current == _M_end)
103 __throw_regex_error(regex_constants::error_escape);
105 if (!_M_is_basic()
106 || (*_M_current != '('
107 && *_M_current != ')'
108 && *_M_current != '{'))
109 {
110 (this->*_M_eat_escape)();
111 return;
112 }
113 __c = *_M_current++;
114 }
115 if (__c == '(')
116 {
117 if (_M_is_ecma() && *_M_current == '?')
118 {
119 if (++_M_current == _M_end)
120 __throw_regex_error(regex_constants::error_paren);
122 if (*_M_current == ':')
123 {
124 ++_M_current;
125 _M_token = _S_token_subexpr_no_group_begin;
126 }
127 else if (*_M_current == '=')
128 {
129 ++_M_current;
130 _M_token = _S_token_subexpr_lookahead_begin;
131 _M_value.assign(1, 'p');
132 }
133 else if (*_M_current == '!')
134 {
135 ++_M_current;
136 _M_token = _S_token_subexpr_lookahead_begin;
137 _M_value.assign(1, 'n');
138 }
139 else
140 __throw_regex_error(regex_constants::error_paren);
141 }
142 else if (_M_flags & regex_constants::nosubs)
143 _M_token = _S_token_subexpr_no_group_begin;
144 else
145 _M_token = _S_token_subexpr_begin;
146 }
147 else if (__c == ')')
148 _M_token = _S_token_subexpr_end;
149 else if (__c == '[')
150 {
151 _M_state = _S_state_in_bracket;
152 _M_at_bracket_start = true;
153 if (_M_current != _M_end && *_M_current == '^')
154 {
155 _M_token = _S_token_bracket_neg_begin;
156 ++_M_current;
157 }
158 else
159 _M_token = _S_token_bracket_begin;
160 }
161 else if (__c == '{')
162 {
163 _M_state = _S_state_in_brace;
164 _M_token = _S_token_interval_begin;
165 }
166 else if (((__pos = std::strchr(_M_spec_char, _M_ctype.narrow(__c, '\0')))
167 != nullptr
168 && *__pos != '\0'
169 && __c != ']'
170 && __c != '}')
171 || (_M_is_grep() && __c == '\n'))
172 {
173 auto __it = _M_token_tbl;
174 auto __narrowc = _M_ctype.narrow(__c, '\0');
175 for (; __it->first != '\0'; ++__it)
176 if (__it->first == __narrowc)
177 {
178 _M_token = __it->second;
179 return;
180 }
181 _GLIBCXX_DEBUG_ASSERT(false);
182 }
183 else
184 {
185 _M_token = _S_token_ord_char;
186 _M_value.assign(1, __c);
187 }
188 }
190 // Differences between styles:
191 // 1) different semantics of "[]" and "[^]".
192 // 2) Escaping in bracket expr.
193 template<typename _CharT>
194 void
195 _Scanner<_CharT>::
196 _M_scan_in_bracket()
197 {
198 if (_M_current == _M_end)
199 __throw_regex_error(regex_constants::error_brack);
201 auto __c = *_M_current++;
203 if (__c == '[')
204 {
205 if (_M_current == _M_end)
206 __throw_regex_error(regex_constants::error_brack);
208 if (*_M_current == '.')
209 {
210 _M_token = _S_token_collsymbol;
211 _M_eat_class(*_M_current++);
212 }
213 else if (*_M_current == ':')
214 {
215 _M_token = _S_token_char_class_name;
216 _M_eat_class(*_M_current++);
217 }
218 else if (*_M_current == '=')
219 {
220 _M_token = _S_token_equiv_class_name;
221 _M_eat_class(*_M_current++);
222 }
223 else
224 {
225 _M_token = _S_token_ord_char;
226 _M_value.assign(1, __c);
227 }
228 }
229 // In POSIX, when encountering "[]" or "[^]", the ']' is interpreted
230 // literally. So "[]]" and "[^]]" are valid regexes. See the testcases
231 // `*/empty_range.cc`.
232 else if (__c == ']' && (_M_is_ecma() || !_M_at_bracket_start))
233 {
234 _M_token = _S_token_bracket_end;
235 _M_state = _S_state_normal;
236 }
237 // ECMAScript and awk permits escaping in bracket.
238 else if (__c == '\\' && (_M_is_ecma() || _M_is_awk()))
239 (this->*_M_eat_escape)();
240 else
241 {
242 _M_token = _S_token_ord_char;
243 _M_value.assign(1, __c);
244 }
245 _M_at_bracket_start = false;
246 }
248 // Differences between styles:
249 // 1) "\}" in basic style.
250 template<typename _CharT>
251 void
252 _Scanner<_CharT>::
253 _M_scan_in_brace()
254 {
255 if (_M_current == _M_end)
256 __throw_regex_error(regex_constants::error_brace);
258 auto __c = *_M_current++;
260 if (_M_ctype.is(_CtypeT::digit, __c))
261 {
262 _M_token = _S_token_dup_count;
263 _M_value.assign(1, __c);
264 while (_M_current != _M_end
265 && _M_ctype.is(_CtypeT::digit, *_M_current))
266 _M_value += *_M_current++;
267 }
268 else if (__c == ',')
269 _M_token = _S_token_comma;
270 // basic use \}.
271 else if (_M_is_basic())
272 {
273 if (__c == '\\' && _M_current != _M_end && *_M_current == '}')
274 {
275 _M_state = _S_state_normal;
276 _M_token = _S_token_interval_end;
277 ++_M_current;
278 }
279 else
280 __throw_regex_error(regex_constants::error_badbrace);
281 }
282 else if (__c == '}')
283 {
284 _M_state = _S_state_normal;
285 _M_token = _S_token_interval_end;
286 }
287 else
288 __throw_regex_error(regex_constants::error_badbrace);
289 }
291 template<typename _CharT>
292 void
293 _Scanner<_CharT>::
294 _M_eat_escape_ecma()
295 {
296 if (_M_current == _M_end)
297 __throw_regex_error(regex_constants::error_escape);
299 auto __c = *_M_current++;
300 auto __pos = _M_find_escape(_M_ctype.narrow(__c, '\0'));
302 if (__pos != nullptr && (__c != 'b' || _M_state == _S_state_in_bracket))
303 {
304 _M_token = _S_token_ord_char;
305 _M_value.assign(1, *__pos);
306 }
307 else if (__c == 'b')
308 {
309 _M_token = _S_token_word_bound;
310 _M_value.assign(1, 'p');
311 }
312 else if (__c == 'B')
313 {
314 _M_token = _S_token_word_bound;
315 _M_value.assign(1, 'n');
316 }
317 // N3376 28.13
318 else if (__c == 'd'
319 || __c == 'D'
320 || __c == 's'
321 || __c == 'S'
322 || __c == 'w'
323 || __c == 'W')
324 {
325 _M_token = _S_token_quoted_class;
326 _M_value.assign(1, __c);
327 }
328 else if (__c == 'c')
329 {
330 if (_M_current == _M_end)
331 __throw_regex_error(regex_constants::error_escape);
332 _M_token = _S_token_ord_char;
333 _M_value.assign(1, *_M_current++);
334 }
335 else if (__c == 'x' || __c == 'u')
336 {
337 _M_value.erase();
338 for (int __i = 0; __i < (__c == 'x' ? 2 : 4); __i++)
339 {
340 if (_M_current == _M_end
341 || !_M_ctype.is(_CtypeT::xdigit, *_M_current))
342 __throw_regex_error(regex_constants::error_escape);
343 _M_value += *_M_current++;
344 }
345 _M_token = _S_token_hex_num;
346 }
347 // ECMAScript recognizes multi-digit back-references.
348 else if (_M_ctype.is(_CtypeT::digit, __c))
349 {
350 _M_value.assign(1, __c);
351 while (_M_current != _M_end
352 && _M_ctype.is(_CtypeT::digit, *_M_current))
353 _M_value += *_M_current++;
354 _M_token = _S_token_backref;
355 }
356 else
357 {
358 _M_token = _S_token_ord_char;
359 _M_value.assign(1, __c);
360 }
361 }
363 // Differences between styles:
364 // 1) Extended doesn't support backref, but basic does.
365 template<typename _CharT>
366 void
367 _Scanner<_CharT>::
368 _M_eat_escape_posix()
369 {
370 if (_M_current == _M_end)
371 __throw_regex_error(regex_constants::error_escape);
373 auto __c = *_M_current;
374 auto __pos = std::strchr(_M_spec_char, _M_ctype.narrow(__c, '\0'));
376 if (__pos != nullptr && *__pos != '\0')
377 {
378 _M_token = _S_token_ord_char;
379 _M_value.assign(1, __c);
380 }
381 // We MUST judge awk before handling backrefs. There's no backref in awk.
382 else if (_M_is_awk())
383 {
384 _M_eat_escape_awk();
385 return;
386 }
387 else if (_M_is_basic() && _M_ctype.is(_CtypeT::digit, __c) && __c != '0')
388 {
389 _M_token = _S_token_backref;
390 _M_value.assign(1, __c);
391 }
392 else
393 {
394 #ifdef __STRICT_ANSI__
395 // POSIX says it is undefined to escape ordinary characters
396 __throw_regex_error(regex_constants::error_escape);
397 #else
398 _M_token = _S_token_ord_char;
399 _M_value.assign(1, __c);
400 #endif
401 }
402 ++_M_current;
403 }
405 template<typename _CharT>
406 void
407 _Scanner<_CharT>::
408 _M_eat_escape_awk()
409 {
410 auto __c = *_M_current++;
411 auto __pos = _M_find_escape(_M_ctype.narrow(__c, '\0'));
413 if (__pos != nullptr)
414 {
415 _M_token = _S_token_ord_char;
416 _M_value.assign(1, *__pos);
417 }
418 // \ddd for oct representation
419 else if (_M_ctype.is(_CtypeT::digit, __c)
420 && __c != '8'
421 && __c != '9')
422 {
423 _M_value.assign(1, __c);
424 for (int __i = 0;
425 __i < 2
426 && _M_current != _M_end
427 && _M_ctype.is(_CtypeT::digit, *_M_current)
428 && *_M_current != '8'
429 && *_M_current != '9';
430 __i++)
431 _M_value += *_M_current++;
432 _M_token = _S_token_oct_num;
433 return;
434 }
435 else
436 __throw_regex_error(regex_constants::error_escape);
437 }
439 // Eats a character class or throws an exception.
440 // __ch could be ':', '.' or '=', _M_current is the char after ']' when
441 // returning.
442 template<typename _CharT>
443 void
444 _Scanner<_CharT>::
445 _M_eat_class(char __ch)
446 {
447 for (_M_value.clear(); _M_current != _M_end && *_M_current != __ch;)
448 _M_value += *_M_current++;
449 if (_M_current == _M_end
450 || *_M_current++ != __ch
451 || _M_current == _M_end // skip __ch
452 || *_M_current++ != ']') // skip ']'
453 {
454 if (__ch == ':')
455 __throw_regex_error(regex_constants::error_ctype);
456 else
457 __throw_regex_error(regex_constants::error_collate);
458 }
459 }
461 #ifdef _GLIBCXX_DEBUG
462 template<typename _CharT>
463 std::ostream&
464 _Scanner<_CharT>::
465 _M_print(std::ostream& ostr)
466 {
467 switch (_M_token)
468 {
469 case _S_token_anychar:
470 ostr << "any-character\n";
471 break;
472 case _S_token_backref:
473 ostr << "backref\n";
474 break;
475 case _S_token_bracket_begin:
476 ostr << "bracket-begin\n";
477 break;
478 case _S_token_bracket_neg_begin:
479 ostr << "bracket-neg-begin\n";
480 break;
481 case _S_token_bracket_end:
482 ostr << "bracket-end\n";
483 break;
484 case _S_token_char_class_name:
485 ostr << "char-class-name \"" << _M_value << "\"\n";
486 break;
487 case _S_token_closure0:
488 ostr << "closure0\n";
489 break;
490 case _S_token_closure1:
491 ostr << "closure1\n";
492 break;
493 case _S_token_collsymbol:
494 ostr << "collsymbol \"" << _M_value << "\"\n";
495 break;
496 case _S_token_comma:
497 ostr << "comma\n";
498 break;
499 case _S_token_dup_count:
500 ostr << "dup count: " << _M_value << "\n";
501 break;
502 case _S_token_eof:
503 ostr << "EOF\n";
504 break;
505 case _S_token_equiv_class_name:
506 ostr << "equiv-class-name \"" << _M_value << "\"\n";
507 break;
508 case _S_token_interval_begin:
509 ostr << "interval begin\n";
510 break;
511 case _S_token_interval_end:
512 ostr << "interval end\n";
513 break;
514 case _S_token_line_begin:
515 ostr << "line begin\n";
516 break;
517 case _S_token_line_end:
518 ostr << "line end\n";
519 break;
520 case _S_token_opt:
521 ostr << "opt\n";
522 break;
523 case _S_token_or:
524 ostr << "or\n";
525 break;
526 case _S_token_ord_char:
527 ostr << "ordinary character: \"" << _M_value << "\"\n";
528 break;
529 case _S_token_subexpr_begin:
530 ostr << "subexpr begin\n";
531 break;
532 case _S_token_subexpr_no_group_begin:
533 ostr << "no grouping subexpr begin\n";
534 break;
535 case _S_token_subexpr_lookahead_begin:
536 ostr << "lookahead subexpr begin\n";
537 break;
538 case _S_token_subexpr_end:
539 ostr << "subexpr end\n";
540 break;
541 case _S_token_unknown:
542 ostr << "-- unknown token --\n";
543 break;
544 case _S_token_oct_num:
545 ostr << "oct number " << _M_value << "\n";
546 break;
547 case _S_token_hex_num:
548 ostr << "hex number " << _M_value << "\n";
549 break;
550 case _S_token_quoted_class:
551 ostr << "quoted class " << "\\" << _M_value << "\n";
552 break;
553 default:
554 _GLIBCXX_DEBUG_ASSERT(false);
555 }
556 return ostr;
557 }
558 #endif
560 _GLIBCXX_END_NAMESPACE_VERSION
561 } // namespace __detail
562 } // namespace