libstdc++
regex_compiler.h
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1 // class template regex -*- C++ -*-
2 
3 // Copyright (C) 2010-2021 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_compiler.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 namespace std _GLIBCXX_VISIBILITY(default)
32 {
33 _GLIBCXX_BEGIN_NAMESPACE_VERSION
34 _GLIBCXX_BEGIN_NAMESPACE_CXX11
35 
36  template<typename>
37  class regex_traits;
38 
39 _GLIBCXX_END_NAMESPACE_CXX11
40 
41 namespace __detail
42 {
43  /**
44  * @addtogroup regex-detail
45  * @{
46  */
47 
48  template<typename, bool, bool>
49  struct _BracketMatcher;
50 
51  /**
52  * @brief Builds an NFA from an input iterator range.
53  *
54  * The %_TraitsT type should fulfill requirements [28.3].
55  */
56  template<typename _TraitsT>
57  class _Compiler
58  {
59  public:
60  typedef typename _TraitsT::char_type _CharT;
61  typedef _NFA<_TraitsT> _RegexT;
63 
64  _Compiler(const _CharT* __b, const _CharT* __e,
65  const typename _TraitsT::locale_type& __traits, _FlagT __flags);
66 
68  _M_get_nfa() noexcept
69  { return std::move(_M_nfa); }
70 
71  private:
72  typedef _Scanner<_CharT> _ScannerT;
73  typedef typename _TraitsT::string_type _StringT;
74  typedef typename _ScannerT::_TokenT _TokenT;
78 
79  // accepts a specific token or returns false.
80  bool
81  _M_match_token(_TokenT __token);
82 
83  void
84  _M_disjunction();
85 
86  void
87  _M_alternative();
88 
89  bool
90  _M_term();
91 
92  bool
93  _M_assertion();
94 
95  bool
96  _M_quantifier();
97 
98  bool
99  _M_atom();
100 
101  bool
102  _M_bracket_expression();
103 
104  template<bool __icase, bool __collate>
105  void
106  _M_insert_any_matcher_ecma();
107 
108  template<bool __icase, bool __collate>
109  void
110  _M_insert_any_matcher_posix();
111 
112  template<bool __icase, bool __collate>
113  void
114  _M_insert_char_matcher();
115 
116  template<bool __icase, bool __collate>
117  void
118  _M_insert_character_class_matcher();
119 
120  template<bool __icase, bool __collate>
121  void
122  _M_insert_bracket_matcher(bool __neg);
123 
124  // Cache of the last atom seen in a bracketed range expression.
125  struct _BracketState
126  {
127  enum class _Type : char { _None, _Char, _Class } _M_type = _Type::_None;
128  _CharT _M_char;
129 
130  void
131  set(_CharT __c) noexcept { _M_type = _Type::_Char; _M_char = __c; }
132 
133  _GLIBCXX_NODISCARD _CharT
134  get() const noexcept { return _M_char; }
135 
136  void
137  reset(_Type __t = _Type::_None) noexcept { _M_type = __t; }
138 
139  explicit operator bool() const noexcept
140  { return _M_type != _Type::_None; }
141 
142  // Previous token was a single character.
143  _GLIBCXX_NODISCARD bool
144  _M_is_char() const noexcept { return _M_type == _Type::_Char; }
145 
146  // Previous token was a character class, equivalent class,
147  // collating symbol etc.
148  _GLIBCXX_NODISCARD bool
149  _M_is_class() const noexcept { return _M_type == _Type::_Class; }
150  };
151 
152  template<bool __icase, bool __collate>
153  using _BracketMatcher
155 
156  // Returns true if successfully parsed one term and should continue
157  // compiling a bracket expression.
158  // Returns false if the compiler should move on.
159  template<bool __icase, bool __collate>
160  bool
161  _M_expression_term(_BracketState& __last_char,
163 
164  int
165  _M_cur_int_value(int __radix);
166 
167  bool
168  _M_try_char();
169 
170  _StateSeqT
171  _M_pop()
172  {
173  auto ret = _M_stack.top();
174  _M_stack.pop();
175  return ret;
176  }
177 
178  static _FlagT
179  _S_validate(_FlagT __f)
180  {
181  using namespace regex_constants;
182  switch (__f & (ECMAScript|basic|extended|awk|grep|egrep))
183  {
184  case ECMAScript:
185  case basic:
186  case extended:
187  case awk:
188  case grep:
189  case egrep:
190  return __f;
191  case _FlagT(0):
192  return __f | ECMAScript;
193  default:
194  std::__throw_regex_error(_S_grammar, "conflicting grammar options");
195  }
196  }
197 
198  _FlagT _M_flags;
199  _ScannerT _M_scanner;
200  shared_ptr<_RegexT> _M_nfa;
201  _StringT _M_value;
202  _StackT _M_stack;
203  const _TraitsT& _M_traits;
204  const _CtypeT& _M_ctype;
205  };
206 
207  // [28.13.14]
208  template<typename _TraitsT, bool __icase, bool __collate>
209  class _RegexTranslatorBase
210  {
211  public:
212  typedef typename _TraitsT::char_type _CharT;
213  typedef typename _TraitsT::string_type _StringT;
214  typedef _StringT _StrTransT;
215 
216  explicit
217  _RegexTranslatorBase(const _TraitsT& __traits)
218  : _M_traits(__traits)
219  { }
220 
221  _CharT
222  _M_translate(_CharT __ch) const
223  {
224  if (__icase)
225  return _M_traits.translate_nocase(__ch);
226  else if (__collate)
227  return _M_traits.translate(__ch);
228  else
229  return __ch;
230  }
231 
232  _StrTransT
233  _M_transform(_CharT __ch) const
234  {
235  _StrTransT __str(1, __ch);
236  return _M_traits.transform(__str.begin(), __str.end());
237  }
238 
239  // See LWG 523. It's not efficiently implementable when _TraitsT is not
240  // std::regex_traits<>, and __collate is true. See specializations for
241  // implementations of other cases.
242  bool
243  _M_match_range(const _StrTransT& __first, const _StrTransT& __last,
244  const _StrTransT& __s) const
245  { return __first <= __s && __s <= __last; }
246 
247  protected:
248  bool _M_in_range_icase(_CharT __first, _CharT __last, _CharT __ch) const
249  {
250  typedef std::ctype<_CharT> __ctype_type;
251  const auto& __fctyp = use_facet<__ctype_type>(this->_M_traits.getloc());
252  auto __lower = __fctyp.tolower(__ch);
253  auto __upper = __fctyp.toupper(__ch);
254  return (__first <= __lower && __lower <= __last)
255  || (__first <= __upper && __upper <= __last);
256  }
257 
258  const _TraitsT& _M_traits;
259  };
260 
261  template<typename _TraitsT, bool __icase, bool __collate>
262  class _RegexTranslator
263  : public _RegexTranslatorBase<_TraitsT, __icase, __collate>
264  {
265  public:
266  typedef _RegexTranslatorBase<_TraitsT, __icase, __collate> _Base;
267  using _Base::_Base;
268  };
269 
270  template<typename _TraitsT, bool __icase>
271  class _RegexTranslator<_TraitsT, __icase, false>
272  : public _RegexTranslatorBase<_TraitsT, __icase, false>
273  {
274  public:
275  typedef _RegexTranslatorBase<_TraitsT, __icase, false> _Base;
276  typedef typename _Base::_CharT _CharT;
277  typedef _CharT _StrTransT;
278 
279  using _Base::_Base;
280 
281  _StrTransT
282  _M_transform(_CharT __ch) const
283  { return __ch; }
284 
285  bool
286  _M_match_range(_CharT __first, _CharT __last, _CharT __ch) const
287  {
288  if (!__icase)
289  return __first <= __ch && __ch <= __last;
290  return this->_M_in_range_icase(__first, __last, __ch);
291  }
292  };
293 
294  template<typename _CharType>
295  class _RegexTranslator<std::regex_traits<_CharType>, true, true>
296  : public _RegexTranslatorBase<std::regex_traits<_CharType>, true, true>
297  {
298  public:
299  typedef _RegexTranslatorBase<std::regex_traits<_CharType>, true, true>
300  _Base;
301  typedef typename _Base::_CharT _CharT;
302  typedef typename _Base::_StrTransT _StrTransT;
303 
304  using _Base::_Base;
305 
306  bool
307  _M_match_range(const _StrTransT& __first, const _StrTransT& __last,
308  const _StrTransT& __str) const
309  {
310  __glibcxx_assert(__first.size() == 1);
311  __glibcxx_assert(__last.size() == 1);
312  __glibcxx_assert(__str.size() == 1);
313  return this->_M_in_range_icase(__first[0], __last[0], __str[0]);
314  }
315  };
316 
317  template<typename _TraitsT>
318  class _RegexTranslator<_TraitsT, false, false>
319  {
320  public:
321  typedef typename _TraitsT::char_type _CharT;
322  typedef _CharT _StrTransT;
323 
324  explicit
325  _RegexTranslator(const _TraitsT&)
326  { }
327 
328  _CharT
329  _M_translate(_CharT __ch) const
330  { return __ch; }
331 
332  _StrTransT
333  _M_transform(_CharT __ch) const
334  { return __ch; }
335 
336  bool
337  _M_match_range(_CharT __first, _CharT __last, _CharT __ch) const
338  { return __first <= __ch && __ch <= __last; }
339  };
340 
341  template<typename _TraitsT, bool __is_ecma, bool __icase, bool __collate>
342  struct _AnyMatcher;
343 
344  template<typename _TraitsT, bool __icase, bool __collate>
345  struct _AnyMatcher<_TraitsT, false, __icase, __collate>
346  {
347  typedef _RegexTranslator<_TraitsT, __icase, __collate> _TransT;
348  typedef typename _TransT::_CharT _CharT;
349 
350  explicit
351  _AnyMatcher(const _TraitsT& __traits)
352  : _M_translator(__traits)
353  { }
354 
355  bool
356  operator()(_CharT __ch) const
357  {
358  static auto __nul = _M_translator._M_translate('\0');
359  return _M_translator._M_translate(__ch) != __nul;
360  }
361 
362  _TransT _M_translator;
363  };
364 
365  template<typename _TraitsT, bool __icase, bool __collate>
366  struct _AnyMatcher<_TraitsT, true, __icase, __collate>
367  {
368  typedef _RegexTranslator<_TraitsT, __icase, __collate> _TransT;
369  typedef typename _TransT::_CharT _CharT;
370 
371  explicit
372  _AnyMatcher(const _TraitsT& __traits)
373  : _M_translator(__traits)
374  { }
375 
376  bool
377  operator()(_CharT __ch) const
378  { return _M_apply(__ch, typename is_same<_CharT, char>::type()); }
379 
380  bool
381  _M_apply(_CharT __ch, true_type) const
382  {
383  auto __c = _M_translator._M_translate(__ch);
384  auto __n = _M_translator._M_translate('\n');
385  auto __r = _M_translator._M_translate('\r');
386  return __c != __n && __c != __r;
387  }
388 
389  bool
390  _M_apply(_CharT __ch, false_type) const
391  {
392  auto __c = _M_translator._M_translate(__ch);
393  auto __n = _M_translator._M_translate('\n');
394  auto __r = _M_translator._M_translate('\r');
395  auto __u2028 = _M_translator._M_translate(u'\u2028');
396  auto __u2029 = _M_translator._M_translate(u'\u2029');
397  return __c != __n && __c != __r && __c != __u2028 && __c != __u2029;
398  }
399 
400  _TransT _M_translator;
401  };
402 
403  template<typename _TraitsT, bool __icase, bool __collate>
404  struct _CharMatcher
405  {
406  typedef _RegexTranslator<_TraitsT, __icase, __collate> _TransT;
407  typedef typename _TransT::_CharT _CharT;
408 
409  _CharMatcher(_CharT __ch, const _TraitsT& __traits)
410  : _M_translator(__traits), _M_ch(_M_translator._M_translate(__ch))
411  { }
412 
413  bool
414  operator()(_CharT __ch) const
415  { return _M_ch == _M_translator._M_translate(__ch); }
416 
417  _TransT _M_translator;
418  _CharT _M_ch;
419  };
420 
421  /// Matches a character range (bracket expression)
422  template<typename _TraitsT, bool __icase, bool __collate>
424  {
425  public:
426  typedef _RegexTranslator<_TraitsT, __icase, __collate> _TransT;
427  typedef typename _TransT::_CharT _CharT;
428  typedef typename _TransT::_StrTransT _StrTransT;
429  typedef typename _TraitsT::string_type _StringT;
430  typedef typename _TraitsT::char_class_type _CharClassT;
431 
432  public:
433  _BracketMatcher(bool __is_non_matching,
434  const _TraitsT& __traits)
435  : _M_class_set(0), _M_translator(__traits), _M_traits(__traits),
436  _M_is_non_matching(__is_non_matching)
437  { }
438 
439  bool
440  operator()(_CharT __ch) const
441  {
442  _GLIBCXX_DEBUG_ASSERT(_M_is_ready);
443  return _M_apply(__ch, _UseCache());
444  }
445 
446  void
447  _M_add_char(_CharT __c)
448  {
449  _M_char_set.push_back(_M_translator._M_translate(__c));
450  _GLIBCXX_DEBUG_ONLY(_M_is_ready = false);
451  }
452 
453  _StringT
454  _M_add_collate_element(const _StringT& __s)
455  {
456  auto __st = _M_traits.lookup_collatename(__s.data(),
457  __s.data() + __s.size());
458  if (__st.empty())
459  __throw_regex_error(regex_constants::error_collate,
460  "Invalid collate element.");
461  _M_char_set.push_back(_M_translator._M_translate(__st[0]));
462  _GLIBCXX_DEBUG_ONLY(_M_is_ready = false);
463  return __st;
464  }
465 
466  void
467  _M_add_equivalence_class(const _StringT& __s)
468  {
469  auto __st = _M_traits.lookup_collatename(__s.data(),
470  __s.data() + __s.size());
471  if (__st.empty())
472  __throw_regex_error(regex_constants::error_collate,
473  "Invalid equivalence class.");
474  __st = _M_traits.transform_primary(__st.data(),
475  __st.data() + __st.size());
476  _M_equiv_set.push_back(__st);
477  _GLIBCXX_DEBUG_ONLY(_M_is_ready = false);
478  }
479 
480  // __neg should be true for \D, \S and \W only.
481  void
482  _M_add_character_class(const _StringT& __s, bool __neg)
483  {
484  auto __mask = _M_traits.lookup_classname(__s.data(),
485  __s.data() + __s.size(),
486  __icase);
487  if (__mask == 0)
488  __throw_regex_error(regex_constants::error_collate,
489  "Invalid character class.");
490  if (!__neg)
491  _M_class_set |= __mask;
492  else
493  _M_neg_class_set.push_back(__mask);
494  _GLIBCXX_DEBUG_ONLY(_M_is_ready = false);
495  }
496 
497  void
498  _M_make_range(_CharT __l, _CharT __r)
499  {
500  if (__l > __r)
501  __throw_regex_error(regex_constants::error_range,
502  "Invalid range in bracket expression.");
503  _M_range_set.push_back(make_pair(_M_translator._M_transform(__l),
504  _M_translator._M_transform(__r)));
505  _GLIBCXX_DEBUG_ONLY(_M_is_ready = false);
506  }
507 
508  void
509  _M_ready()
510  {
511  std::sort(_M_char_set.begin(), _M_char_set.end());
512  auto __end = std::unique(_M_char_set.begin(), _M_char_set.end());
513  _M_char_set.erase(__end, _M_char_set.end());
514  _M_make_cache(_UseCache());
515  _GLIBCXX_DEBUG_ONLY(_M_is_ready = true);
516  }
517 
518  private:
519  // Currently we only use the cache for char
521 
522  static constexpr size_t
523  _S_cache_size =
524  1ul << (sizeof(_CharT) * __CHAR_BIT__ * int(_UseCache::value));
525 
526  struct _Dummy { };
527  typedef typename std::conditional<_UseCache::value,
529  _Dummy>::type _CacheT;
530  typedef typename std::make_unsigned<_CharT>::type _UnsignedCharT;
531 
532  bool
533  _M_apply(_CharT __ch, false_type) const;
534 
535  bool
536  _M_apply(_CharT __ch, true_type) const
537  { return _M_cache[static_cast<_UnsignedCharT>(__ch)]; }
538 
539  void
540  _M_make_cache(true_type)
541  {
542  for (unsigned __i = 0; __i < _M_cache.size(); __i++)
543  _M_cache[__i] = _M_apply(static_cast<_CharT>(__i), false_type());
544  }
545 
546  void
547  _M_make_cache(false_type)
548  { }
549 
550  private:
551  std::vector<_CharT> _M_char_set;
552  std::vector<_StringT> _M_equiv_set;
554  std::vector<_CharClassT> _M_neg_class_set;
555  _CharClassT _M_class_set;
556  _TransT _M_translator;
557  const _TraitsT& _M_traits;
558  bool _M_is_non_matching;
559  _CacheT _M_cache;
560 #ifdef _GLIBCXX_DEBUG
561  bool _M_is_ready = false;
562 #endif
563  };
564 
565  ///@} regex-detail
566 } // namespace __detail
567 _GLIBCXX_END_NAMESPACE_VERSION
568 } // namespace std
569 
570 #include <bits/regex_compiler.tcc>
integral_constant< bool, true > true_type
The type used as a compile-time boolean with true value.
Definition: type_traits:83
integral_constant< bool, false > false_type
The type used as a compile-time boolean with false value.
Definition: type_traits:86
constexpr std::remove_reference< _Tp >::type && move(_Tp &&__t) noexcept
Convert a value to an rvalue.
Definition: move.h:104
ISO C++ entities toplevel namespace is std.
constexpr error_type error_range(_S_error_range)
constexpr syntax_option_type ECMAScript
constexpr syntax_option_type egrep
syntax_option_type
This is a bitmask type indicating how to interpret the regex.
constexpr syntax_option_type awk
constexpr syntax_option_type extended
constexpr syntax_option_type basic
constexpr error_type error_collate(_S_error_collate)
constexpr syntax_option_type grep
The bitset class represents a fixed-size sequence of bits.
Definition: bitset:753
integral_constant
Definition: type_traits:66
Define a member typedef type to one of two argument types.
Definition: type_traits:2227
Primary class template ctype facet.
Describes a sequence of one or more _State, its current start and end(s). This structure contains fra...
Matches a character range (bracket expression)
Builds an NFA from an input iterator range.
Scans an input range for regex tokens.
A smart pointer with reference-counted copy semantics.
A standard container made up of unique keys, which can be retrieved in logarithmic time.
Definition: stl_set.h:95
Struct holding two objects of arbitrary type.
Definition: stl_pair.h:213
void pop()
Removes first element.
Definition: stl_stack.h:272
reference top()
Definition: stl_stack.h:212