libstdc++-v3/include/bits/regex_compiler.tcc

   1 // class template regex -*- C++ -*-
   2
   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.
  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.tcc
  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 // FIXME make comments doxygen format.
  32
  33 // This compiler refers to "Regular Expression Matching Can Be Simple And Fast"
  34 // (http://swtch.com/~rsc/regexp/regexp1.html"),
  35 // but doesn't strictly follow it.
  36 //
  37 // When compiling, states are *chained* instead of tree- or graph-constructed.
  38 // It's more like structured programs: there's if statement and loop statement.
  39 //
  40 // For alternative structure (say "a|b"), aka "if statement", two branches
  41 // should be constructed. However, these two shall merge to an "end_tag" at
  42 // the end of this operator:
  43 //
  44 //                branch1
  45 //              /        \
  46 // => begin_tag            end_tag =>
  47 //              \        /
  48 //                branch2
  49 //
  50 // This is the difference between this implementation and that in Russ's
  51 // article.
  52 //
  53 // That's why we introduced dummy node here ------ "end_tag" is a dummy node.
  54 // All dummy node will be eliminated at the end of compiling process.
  55
  56 namespace std _GLIBCXX_VISIBILITY(default)
  57 {
  58 namespace __detail
  59 {
  60 _GLIBCXX_BEGIN_NAMESPACE_VERSION
  61
  62   template<typename _TraitsT>
  63     _Compiler<_TraitsT>::
  64     _Compiler(_IterT __b, _IterT __e,
  65               const typename _TraitsT::locale_type& __loc, _FlagT __flags)
  66     : _M_flags((__flags
  67                 & (regex_constants::ECMAScript
  68                    | regex_constants::basic
  69                    | regex_constants::extended
  70                    | regex_constants::grep
  71                    | regex_constants::egrep
  72                    | regex_constants::awk))
  73                ? __flags
  74                : __flags | regex_constants::ECMAScript),
  75       _M_scanner(__b, __e, _M_flags, __loc),
  76       _M_nfa(make_shared<_RegexT>(__loc, _M_flags)),
  77       _M_traits(_M_nfa->_M_traits),
  78       _M_ctype(std::use_facet<_CtypeT>(__loc))
  79     {
  80       _StateSeqT __r(*_M_nfa, _M_nfa->_M_start());
  81       __r._M_append(_M_nfa->_M_insert_subexpr_begin());
  82       this->_M_disjunction();
  83       if (!_M_match_token(_ScannerT::_S_token_eof))
  84         __throw_regex_error(regex_constants::error_paren);
  85       __r._M_append(_M_pop());
  86       _GLIBCXX_DEBUG_ASSERT(_M_stack.empty());
  87       __r._M_append(_M_nfa->_M_insert_subexpr_end());
  88       __r._M_append(_M_nfa->_M_insert_accept());
  89       _M_nfa->_M_eliminate_dummy();
  90     }
  91
  92   template<typename _TraitsT>
  93     void
  94     _Compiler<_TraitsT>::
  95     _M_disjunction()
  96     {
  97       this->_M_alternative();
  98       while (_M_match_token(_ScannerT::_S_token_or))
  99         {
 100           _StateSeqT __alt1 = _M_pop();
 101           this->_M_alternative();
 102           _StateSeqT __alt2 = _M_pop();
 103           auto __end = _M_nfa->_M_insert_dummy();
 104           __alt1._M_append(__end);
 105           __alt2._M_append(__end);
 106           // __alt2 is state._M_next, __alt1 is state._M_alt. The executor
 107           // executes _M_alt before _M_next, as well as executing left
 108           // alternative before right one.
 109           _M_stack.push(_StateSeqT(*_M_nfa,
 110                                    _M_nfa->_M_insert_alt(
 111                                      __alt2._M_start, __alt1._M_start, false),
 112                                    __end));
 113         }
 114     }
 115
 116   template<typename _TraitsT>
 117     void
 118     _Compiler<_TraitsT>::
 119     _M_alternative()
 120     {
 121       if (this->_M_term())
 122         {
 123           _StateSeqT __re = _M_pop();
 124           this->_M_alternative();
 125           __re._M_append(_M_pop());
 126           _M_stack.push(__re);
 127         }
 128       else
 129         _M_stack.push(_StateSeqT(*_M_nfa, _M_nfa->_M_insert_dummy()));
 130     }
 131
 132   template<typename _TraitsT>
 133     bool
 134     _Compiler<_TraitsT>::
 135     _M_term()
 136     {
 137       if (this->_M_assertion())
 138         return true;
 139       if (this->_M_atom())
 140         {
 141           while (this->_M_quantifier());
 142           return true;
 143         }
 144       return false;
 145     }
 146
 147   template<typename _TraitsT>
 148     bool
 149     _Compiler<_TraitsT>::
 150     _M_assertion()
 151     {
 152       if (_M_match_token(_ScannerT::_S_token_line_begin))
 153         _M_stack.push(_StateSeqT(*_M_nfa, _M_nfa->_M_insert_line_begin()));
 154       else if (_M_match_token(_ScannerT::_S_token_line_end))
 155         _M_stack.push(_StateSeqT(*_M_nfa, _M_nfa->_M_insert_line_end()));
 156       else if (_M_match_token(_ScannerT::_S_token_word_bound))
 157         // _M_value[0] == 'n' means it's negative, say "not word boundary".
 158         _M_stack.push(_StateSeqT(*_M_nfa, _M_nfa->
 159               _M_insert_word_bound(_M_value[0] == 'n')));
 160       else if (_M_match_token(_ScannerT::_S_token_subexpr_lookahead_begin))
 161         {
 162           auto __neg = _M_value[0] == 'n';
 163           this->_M_disjunction();
 164           if (!_M_match_token(_ScannerT::_S_token_subexpr_end))
 165             __throw_regex_error(regex_constants::error_paren);
 166           auto __tmp = _M_pop();
 167           __tmp._M_append(_M_nfa->_M_insert_accept());
 168           _M_stack.push(
 169               _StateSeqT(
 170                 *_M_nfa,
 171                 _M_nfa->_M_insert_lookahead(__tmp._M_start, __neg)));
 172         }
 173       else
 174         return false;
 175       return true;
 176     }
 177
 178   template<typename _TraitsT>
 179     bool
 180     _Compiler<_TraitsT>::
 181     _M_quantifier()
 182     {
 183       bool __neg = (_M_flags & regex_constants::ECMAScript);
 184       auto __init = [this, &__neg]()
 185         {
 186           if (_M_stack.empty())
 187             __throw_regex_error(regex_constants::error_badrepeat);
 188           __neg = __neg && _M_match_token(_ScannerT::_S_token_opt);
 189         };
 190       if (_M_match_token(_ScannerT::_S_token_closure0))
 191         {
 192           __init();
 193           auto __e = _M_pop();
 194           _StateSeqT __r(*_M_nfa,
 195                          _M_nfa->_M_insert_repeat(_S_invalid_state_id,
 196                                                   __e._M_start, __neg));
 197           __e._M_append(__r);
 198           _M_stack.push(__r);
 199         }
 200       else if (_M_match_token(_ScannerT::_S_token_closure1))
 201         {
 202           __init();
 203           auto __e = _M_pop();
 204           __e._M_append(_M_nfa->_M_insert_repeat(_S_invalid_state_id,
 205                                                  __e._M_start, __neg));
 206           _M_stack.push(__e);
 207         }
 208       else if (_M_match_token(_ScannerT::_S_token_opt))
 209         {
 210           __init();
 211           auto __e = _M_pop();
 212           auto __end = _M_nfa->_M_insert_dummy();
 213           _StateSeqT __r(*_M_nfa,
 214                          _M_nfa->_M_insert_repeat(_S_invalid_state_id,
 215                                                   __e._M_start, __neg));
 216           __e._M_append(__end);
 217           __r._M_append(__end);
 218           _M_stack.push(__r);
 219         }
 220       else if (_M_match_token(_ScannerT::_S_token_interval_begin))
 221         {
 222           if (_M_stack.empty())
 223             __throw_regex_error(regex_constants::error_badrepeat);
 224           if (!_M_match_token(_ScannerT::_S_token_dup_count))
 225             __throw_regex_error(regex_constants::error_badbrace);
 226           _StateSeqT __r(_M_pop());
 227           _StateSeqT __e(*_M_nfa, _M_nfa->_M_insert_dummy());
 228           long __min_rep = _M_cur_int_value(10);
 229           bool __infi = false;
 230           long __n;
 231
 232           // {3
 233           if (_M_match_token(_ScannerT::_S_token_comma))
 234             if (_M_match_token(_ScannerT::_S_token_dup_count)) // {3,7}
 235               __n = _M_cur_int_value(10) - __min_rep;
 236             else
 237               __infi = true;
 238           else
 239             __n = 0;
 240           if (!_M_match_token(_ScannerT::_S_token_interval_end))
 241             __throw_regex_error(regex_constants::error_brace);
 242
 243           __neg = __neg && _M_match_token(_ScannerT::_S_token_opt);
 244
 245           for (long __i = 0; __i < __min_rep; ++__i)
 246             __e._M_append(__r._M_clone());
 247
 248           if (__infi)
 249             {
 250               auto __tmp = __r._M_clone();
 251               _StateSeqT __s(*_M_nfa,
 252                              _M_nfa->_M_insert_repeat(_S_invalid_state_id,
 253                                                       __tmp._M_start, __neg));
 254               __tmp._M_append(__s);
 255               __e._M_append(__s);
 256             }
 257           else
 258             {
 259               if (__n < 0)
 260                 __throw_regex_error(regex_constants::error_badbrace);
 261               auto __end = _M_nfa->_M_insert_dummy();
 262               // _M_alt is the "match more" branch, and _M_next is the
 263               // "match less" one. Switch _M_alt and _M_next of all created
 264               // nodes. This is a hack but IMO works well.
 265               std::stack<_StateIdT> __stack;
 266               for (long __i = 0; __i < __n; ++__i)
 267                 {
 268                   auto __tmp = __r._M_clone();
 269                   auto __alt = _M_nfa->_M_insert_repeat(__tmp._M_start,
 270                                                         __end, __neg);
 271                   __stack.push(__alt);
 272                   __e._M_append(_StateSeqT(*_M_nfa, __alt, __tmp._M_end));
 273                 }
 274               __e._M_append(__end);
 275               while (!__stack.empty())
 276                 {
 277                   auto& __tmp = (*_M_nfa)[__stack.top()];
 278                   __stack.pop();
 279                   std::swap(__tmp._M_next, __tmp._M_alt);
 280                 }
 281             }
 282           _M_stack.push(__e);
 283         }
 284       else
 285         return false;
 286       return true;
 287     }
 288
 289 #define __INSERT_REGEX_MATCHER(__func, args...)\
 290         do\
 291           if (!(_M_flags & regex_constants::icase))\
 292             if (!(_M_flags & regex_constants::collate))\
 293               __func<false, false>(args);\
 294             else\
 295               __func<false, true>(args);\
 296           else\
 297             if (!(_M_flags & regex_constants::collate))\
 298               __func<true, false>(args);\
 299             else\
 300               __func<true, true>(args);\
 301         while (false)
 302
 303   template<typename _TraitsT>
 304     bool
 305     _Compiler<_TraitsT>::
 306     _M_atom()
 307     {
 308       if (_M_match_token(_ScannerT::_S_token_anychar))
 309         {
 310           if (!(_M_flags & regex_constants::ECMAScript))
 311             __INSERT_REGEX_MATCHER(_M_insert_any_matcher_posix);
 312           else
 313             __INSERT_REGEX_MATCHER(_M_insert_any_matcher_ecma);
 314         }
 315       else if (_M_try_char())
 316         __INSERT_REGEX_MATCHER(_M_insert_char_matcher);
 317       else if (_M_match_token(_ScannerT::_S_token_backref))
 318         _M_stack.push(_StateSeqT(*_M_nfa, _M_nfa->
 319                                  _M_insert_backref(_M_cur_int_value(10))));
 320       else if (_M_match_token(_ScannerT::_S_token_quoted_class))
 321         __INSERT_REGEX_MATCHER(_M_insert_character_class_matcher);
 322       else if (_M_match_token(_ScannerT::_S_token_subexpr_no_group_begin))
 323         {
 324           _StateSeqT __r(*_M_nfa, _M_nfa->_M_insert_dummy());
 325           this->_M_disjunction();
 326           if (!_M_match_token(_ScannerT::_S_token_subexpr_end))
 327             __throw_regex_error(regex_constants::error_paren);
 328           __r._M_append(_M_pop());
 329           _M_stack.push(__r);
 330         }
 331       else if (_M_match_token(_ScannerT::_S_token_subexpr_begin))
 332         {
 333           _StateSeqT __r(*_M_nfa, _M_nfa->_M_insert_subexpr_begin());
 334           this->_M_disjunction();
 335           if (!_M_match_token(_ScannerT::_S_token_subexpr_end))
 336             __throw_regex_error(regex_constants::error_paren);
 337           __r._M_append(_M_pop());
 338           __r._M_append(_M_nfa->_M_insert_subexpr_end());
 339           _M_stack.push(__r);
 340         }
 341       else if (!_M_bracket_expression())
 342         return false;
 343       return true;
 344     }
 345
 346   template<typename _TraitsT>
 347     bool
 348     _Compiler<_TraitsT>::
 349     _M_bracket_expression()
 350     {
 351       bool __neg =
 352         _M_match_token(_ScannerT::_S_token_bracket_neg_begin);
 353       if (!(__neg || _M_match_token(_ScannerT::_S_token_bracket_begin)))
 354         return false;
 355       __INSERT_REGEX_MATCHER(_M_insert_bracket_matcher, __neg);
 356       return true;
 357     }
 358 #undef __INSERT_REGEX_MATCHER
 359
 360   template<typename _TraitsT>
 361   template<bool __icase, bool __collate>
 362     void
 363     _Compiler<_TraitsT>::
 364     _M_insert_any_matcher_ecma()
 365     {
 366       _M_stack.push(_StateSeqT(*_M_nfa,
 367         _M_nfa->_M_insert_matcher
 368           (_AnyMatcher<_TraitsT, true, __icase, __collate>
 369             (_M_traits))));
 370     }
 371
 372   template<typename _TraitsT>
 373   template<bool __icase, bool __collate>
 374     void
 375     _Compiler<_TraitsT>::
 376     _M_insert_any_matcher_posix()
 377     {
 378       _M_stack.push(_StateSeqT(*_M_nfa,
 379         _M_nfa->_M_insert_matcher
 380           (_AnyMatcher<_TraitsT, false, __icase, __collate>
 381             (_M_traits))));
 382     }
 383
 384   template<typename _TraitsT>
 385   template<bool __icase, bool __collate>
 386     void
 387     _Compiler<_TraitsT>::
 388     _M_insert_char_matcher()
 389     {
 390       _M_stack.push(_StateSeqT(*_M_nfa,
 391         _M_nfa->_M_insert_matcher
 392           (_CharMatcher<_TraitsT, __icase, __collate>
 393             (_M_value[0], _M_traits))));
 394     }
 395
 396   template<typename _TraitsT>
 397   template<bool __icase, bool __collate>
 398     void
 399     _Compiler<_TraitsT>::
 400     _M_insert_character_class_matcher()
 401     {
 402       _GLIBCXX_DEBUG_ASSERT(_M_value.size() == 1);
 403       _BracketMatcher<_TraitsT, __icase, __collate> __matcher
 404         (_M_ctype.is(_CtypeT::upper, _M_value[0]), _M_traits);
 405       __matcher._M_add_character_class(_M_value, false);
 406       __matcher._M_ready();
 407       _M_stack.push(_StateSeqT(*_M_nfa,
 408         _M_nfa->_M_insert_matcher(std::move(__matcher))));
 409     }
 410
 411   template<typename _TraitsT>
 412   template<bool __icase, bool __collate>
 413     void
 414     _Compiler<_TraitsT>::
 415     _M_insert_bracket_matcher(bool __neg)
 416     {
 417       _BracketMatcher<_TraitsT, __icase, __collate> __matcher(__neg, _M_traits);
 418       pair<bool, _CharT> __last_char; // Optional<_CharT>
 419       __last_char.first = false;
 420       if (!(_M_flags & regex_constants::ECMAScript))
 421         if (_M_try_char())
 422           {
 423             __matcher._M_add_char(_M_value[0]);
 424             __last_char.first = true;
 425             __last_char.second = _M_value[0];
 426           }
 427       while (!_M_match_token(_ScannerT::_S_token_bracket_end))
 428         _M_expression_term(__last_char, __matcher);
 429       __matcher._M_ready();
 430       _M_stack.push(_StateSeqT(
 431                       *_M_nfa,
 432                       _M_nfa->_M_insert_matcher(std::move(__matcher))));
 433     }
 434
 435   template<typename _TraitsT>
 436   template<bool __icase, bool __collate>
 437     void
 438     _Compiler<_TraitsT>::
 439     _M_expression_term(pair<bool, _CharT>& __last_char,
 440                        _BracketMatcher<_TraitsT, __icase, __collate>& __matcher)
 441     {
 442       if (_M_match_token(_ScannerT::_S_token_collsymbol))
 443         __matcher._M_add_collating_element(_M_value);
 444       else if (_M_match_token(_ScannerT::_S_token_equiv_class_name))
 445         __matcher._M_add_equivalence_class(_M_value);
 446       else if (_M_match_token(_ScannerT::_S_token_char_class_name))
 447         __matcher._M_add_character_class(_M_value, false);
 448       // POSIX doesn't permit '-' as a start-range char (say [a-z--0]),
 449       // except when the '-' is the first character in the bracket expression
 450       // ([--0]). ECMAScript treats all '-' after a range as a normal character.
 451       // Also see above, where _M_expression_term gets called.
 452       //
 453       // As a result, POSIX rejects [-----], but ECMAScript doesn't.
 454       // Boost (1.57.0) always uses POSIX style even in its ECMAScript syntax.
 455       // Clang (3.5) always uses ECMAScript style even in its POSIX syntax.
 456       //
 457       // It turns out that no one reads BNFs ;)
 458       else if (_M_try_char())
 459         {
 460           if (!__last_char.first)
 461             {
 462               if (_M_value[0] == '-'
 463                   && !(_M_flags & regex_constants::ECMAScript))
 464                 __throw_regex_error(regex_constants::error_range);
 465               __matcher._M_add_char(_M_value[0]);
 466               __last_char.first = true;
 467               __last_char.second = _M_value[0];
 468             }
 469           else
 470             {
 471               if (_M_value[0] == '-')
 472                 {
 473                   if (_M_try_char())
 474                     {
 475                       __matcher._M_make_range(__last_char.second , _M_value[0]);
 476                       __last_char.first = false;
 477                     }
 478                   else
 479                     {
 480                       if (_M_scanner._M_get_token()
 481                           != _ScannerT::_S_token_bracket_end)
 482                         __throw_regex_error(regex_constants::error_range);
 483                       __matcher._M_add_char(_M_value[0]);
 484                     }
 485                 }
 486               else
 487                 {
 488                   __matcher._M_add_char(_M_value[0]);
 489                   __last_char.second = _M_value[0];
 490                 }
 491             }
 492         }
 493       else if (_M_match_token(_ScannerT::_S_token_quoted_class))
 494         __matcher._M_add_character_class(_M_value,
 495                                          _M_ctype.is(_CtypeT::upper,
 496                                                      _M_value[0]));
 497       else
 498         __throw_regex_error(regex_constants::error_brack);
 499     }
 500
 501   template<typename _TraitsT>
 502     bool
 503     _Compiler<_TraitsT>::
 504     _M_try_char()
 505     {
 506       bool __is_char = false;
 507       if (_M_match_token(_ScannerT::_S_token_oct_num))
 508         {
 509           __is_char = true;
 510           _M_value.assign(1, _M_cur_int_value(8));
 511         }
 512       else if (_M_match_token(_ScannerT::_S_token_hex_num))
 513         {
 514           __is_char = true;
 515           _M_value.assign(1, _M_cur_int_value(16));
 516         }
 517       else if (_M_match_token(_ScannerT::_S_token_ord_char))
 518         __is_char = true;
 519       return __is_char;
 520     }
 521
 522   template<typename _TraitsT>
 523     bool
 524     _Compiler<_TraitsT>::
 525     _M_match_token(_TokenT token)
 526     {
 527       if (token == _M_scanner._M_get_token())
 528         {
 529           _M_value = _M_scanner._M_get_value();
 530           _M_scanner._M_advance();
 531           return true;
 532         }
 533       return false;
 534     }
 535
 536   template<typename _TraitsT>
 537     int
 538     _Compiler<_TraitsT>::
 539     _M_cur_int_value(int __radix)
 540     {
 541       long __v = 0;
 542       for (typename _StringT::size_type __i = 0;
 543            __i < _M_value.length(); ++__i)
 544         __v =__v * __radix + _M_traits.value(_M_value[__i], __radix);
 545       return __v;
 546     }
 547
 548   template<typename _TraitsT, bool __icase, bool __collate>
 549     bool
 550     _BracketMatcher<_TraitsT, __icase, __collate>::
 551     _M_apply(_CharT __ch, false_type) const
 552     {
 553       bool __ret = std::binary_search(_M_char_set.begin(), _M_char_set.end(),
 554                                       _M_translator._M_translate(__ch));
 555       if (!__ret)
 556         {
 557           auto __s = _M_translator._M_transform(__ch);
 558           for (auto& __it : _M_range_set)
 559             if (__it.first <= __s && __s <= __it.second)
 560               {
 561                 __ret = true;
 562                 break;
 563               }
 564           if (_M_traits.isctype(__ch, _M_class_set))
 565             __ret = true;
 566           else if (std::find(_M_equiv_set.begin(), _M_equiv_set.end(),
 567                              _M_traits.transform_primary(&__ch, &__ch+1))
 568                    != _M_equiv_set.end())
 569             __ret = true;
 570           else
 571             {
 572               for (auto& __it : _M_neg_class_set)
 573                 if (!_M_traits.isctype(__ch, __it))
 574                   {
 575                     __ret = true;
 576                     break;
 577                   }
 578             }
 579         }
 580       if (_M_is_non_matching)
 581         return !__ret;
 582       else
 583         return __ret;
 584     }
 585
 586 _GLIBCXX_END_NAMESPACE_VERSION
 587 } // namespace __detail
 588 } // namespace