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

   1 // class template regex -*- C++ -*-
   2
   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.
  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 branchs should
  41 // be constructed. However, these two shall merge to an "end_tag" at the end of
  42 // 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 _TraitsT& __traits, _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_traits(__traits),
  76     _M_ctype(std::use_facet<_CtypeT>(_M_traits.getloc())),
  77     _M_scanner(__b, __e, _M_flags, _M_traits.getloc()),
  78     _M_nfa(_M_flags)
  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           _M_stack.push(_StateSeqT(_M_nfa,
 107                                    _M_nfa._M_insert_alt(__alt1._M_start,
 108                                                         __alt2._M_start, false),
 109                                    __end));
 110         }
 111     }
 112
 113   template<typename _TraitsT>
 114     void
 115     _Compiler<_TraitsT>::
 116     _M_alternative()
 117     {
 118       if (this->_M_term())
 119         {
 120           _StateSeqT __re = _M_pop();
 121           this->_M_alternative();
 122           __re._M_append(_M_pop());
 123           _M_stack.push(__re);
 124         }
 125       else
 126         _M_stack.push(_StateSeqT(_M_nfa, _M_nfa._M_insert_dummy()));
 127     }
 128
 129   template<typename _TraitsT>
 130     bool
 131     _Compiler<_TraitsT>::
 132     _M_term()
 133     {
 134       if (this->_M_assertion())
 135         return true;
 136       if (this->_M_atom())
 137         {
 138           this->_M_quantifier();
 139           return true;
 140         }
 141       return false;
 142     }
 143
 144   template<typename _TraitsT>
 145     bool
 146     _Compiler<_TraitsT>::
 147     _M_assertion()
 148     {
 149       if (_M_match_token(_ScannerT::_S_token_line_begin))
 150         _M_stack.push(_StateSeqT(_M_nfa, _M_nfa._M_insert_line_begin()));
 151       else if (_M_match_token(_ScannerT::_S_token_line_end))
 152         _M_stack.push(_StateSeqT(_M_nfa, _M_nfa._M_insert_line_end()));
 153       else if (_M_match_token(_ScannerT::_S_token_word_bound))
 154         // _M_value[0] == 'n' means it's negtive, say "not word boundary".
 155         _M_stack.push(_StateSeqT(_M_nfa, _M_nfa.
 156               _M_insert_word_bound(_M_value[0] == 'n')));
 157       else if (_M_match_token(_ScannerT::_S_token_subexpr_lookahead_begin))
 158         {
 159           auto __neg = _M_value[0] == 'n';
 160           this->_M_disjunction();
 161           if (!_M_match_token(_ScannerT::_S_token_subexpr_end))
 162             __throw_regex_error(regex_constants::error_paren);
 163           auto __tmp = _M_pop();
 164           __tmp._M_append(_M_nfa._M_insert_accept());
 165           _M_stack.push(
 166               _StateSeqT(
 167                 _M_nfa,
 168                 _M_nfa._M_insert_lookahead(__tmp._M_start, __neg)));
 169         }
 170       else
 171         return false;
 172       return true;
 173     }
 174
 175   template<typename _TraitsT>
 176     void
 177     _Compiler<_TraitsT>::
 178     _M_quantifier()
 179     {
 180       bool __neg = (_M_flags & regex_constants::ECMAScript);
 181       auto __init = [this, &__neg]()
 182         {
 183           if (_M_stack.empty())
 184             __throw_regex_error(regex_constants::error_badrepeat);
 185           __neg = __neg && _M_match_token(_ScannerT::_S_token_opt);
 186         };
 187       if (_M_match_token(_ScannerT::_S_token_closure0))
 188         {
 189           __init();
 190           auto __e = _M_pop();
 191           _StateSeqT __r(_M_nfa, _M_nfa._M_insert_alt(_S_invalid_state_id,
 192                                                       __e._M_start, __neg));
 193           __e._M_append(__r);
 194           _M_stack.push(__r);
 195         }
 196       else if (_M_match_token(_ScannerT::_S_token_closure1))
 197         {
 198           __init();
 199           auto __e = _M_pop();
 200           __e._M_append(_M_nfa._M_insert_alt(_S_invalid_state_id, __e._M_start,
 201                                              __neg));
 202           _M_stack.push(__e);
 203         }
 204       else if (_M_match_token(_ScannerT::_S_token_opt))
 205         {
 206           __init();
 207           auto __e = _M_pop();
 208           auto __end = _M_nfa._M_insert_dummy();
 209           _StateSeqT __r(_M_nfa, _M_nfa._M_insert_alt(_S_invalid_state_id,
 210                                                       __e._M_start, __neg));
 211           __e._M_append(__end);
 212           __r._M_append(__end);
 213           _M_stack.push(__r);
 214         }
 215       else if (_M_match_token(_ScannerT::_S_token_interval_begin))
 216         {
 217           if (_M_stack.empty())
 218             __throw_regex_error(regex_constants::error_badrepeat);
 219           if (!_M_match_token(_ScannerT::_S_token_dup_count))
 220             __throw_regex_error(regex_constants::error_badbrace);
 221           _StateSeqT __r(_M_pop());
 222           _StateSeqT __e(_M_nfa, _M_nfa._M_insert_dummy());
 223           long __min_rep = _M_cur_int_value(10);
 224           bool __infi = false;
 225           long __n;
 226
 227           // {3
 228           if (_M_match_token(_ScannerT::_S_token_comma))
 229             if (_M_match_token(_ScannerT::_S_token_dup_count)) // {3,7}
 230               __n = _M_cur_int_value(10) - __min_rep;
 231             else
 232               __infi = true;
 233           else
 234             __n = 0;
 235           if (!_M_match_token(_ScannerT::_S_token_interval_end))
 236             __throw_regex_error(regex_constants::error_brace);
 237
 238           __neg = __neg && _M_match_token(_ScannerT::_S_token_opt);
 239
 240           for (long __i = 0; __i < __min_rep; ++__i)
 241             __e._M_append(__r._M_clone());
 242
 243           if (__infi)
 244             {
 245               auto __tmp = __r._M_clone();
 246               _StateSeqT __s(_M_nfa,
 247                              _M_nfa._M_insert_alt(_S_invalid_state_id,
 248                                                   __tmp._M_start, __neg));
 249               __tmp._M_append(__s);
 250               __e._M_append(__s);
 251             }
 252           else
 253             {
 254               if (__n < 0)
 255                 __throw_regex_error(regex_constants::error_badbrace);
 256               auto __end = _M_nfa._M_insert_dummy();
 257               // _M_alt is the "match more" branch, and _M_next is the
 258               // "match less" one. Switch _M_alt and _M_next of all created
 259               // nodes. This is a hacking but IMO works well.
 260               std::stack<_StateIdT> __stack;
 261               for (long __i = 0; __i < __n; ++__i)
 262                 {
 263                   auto __tmp = __r._M_clone();
 264                   auto __alt = _M_nfa._M_insert_alt(__tmp._M_start,
 265                                                     __end, __neg);
 266                   __stack.push(__alt);
 267                   __e._M_append(_StateSeqT(_M_nfa, __alt, __tmp._M_end));
 268                 }
 269               __e._M_append(__end);
 270               while (!__stack.empty())
 271                 {
 272                   auto& __tmp = _M_nfa[__stack.top()];
 273                   __stack.pop();
 274                   swap(__tmp._M_next, __tmp._M_alt);
 275                 }
 276             }
 277           _M_stack.push(__e);
 278         }
 279     }
 280
 281 #define __INSERT_REGEX_MATCHER(__func, args...)\
 282         do\
 283           if (!(_M_flags & regex_constants::icase))\
 284             if (!(_M_flags & regex_constants::collate))\
 285               __func<false, false>(args);\
 286             else\
 287               __func<false, true>(args);\
 288           else\
 289             if (!(_M_flags & regex_constants::collate))\
 290               __func<true, false>(args);\
 291             else\
 292               __func<true, true>(args);\
 293         while (false)
 294
 295   template<typename _TraitsT>
 296     bool
 297     _Compiler<_TraitsT>::
 298     _M_atom()
 299     {
 300       if (_M_match_token(_ScannerT::_S_token_anychar))
 301         {
 302           if (!(_M_flags & regex_constants::ECMAScript))
 303             __INSERT_REGEX_MATCHER(_M_insert_any_matcher_posix);
 304           else
 305             __INSERT_REGEX_MATCHER(_M_insert_any_matcher_ecma);
 306         }
 307       else if (_M_try_char())
 308         __INSERT_REGEX_MATCHER(_M_insert_char_matcher);
 309       else if (_M_match_token(_ScannerT::_S_token_backref))
 310         _M_stack.push(_StateSeqT(_M_nfa, _M_nfa.
 311                                  _M_insert_backref(_M_cur_int_value(10))));
 312       else if (_M_match_token(_ScannerT::_S_token_quoted_class))
 313         __INSERT_REGEX_MATCHER(_M_insert_character_class_matcher);
 314       else if (_M_match_token(_ScannerT::_S_token_subexpr_no_group_begin))
 315         {
 316           _StateSeqT __r(_M_nfa, _M_nfa._M_insert_dummy());
 317           this->_M_disjunction();
 318           if (!_M_match_token(_ScannerT::_S_token_subexpr_end))
 319             __throw_regex_error(regex_constants::error_paren);
 320           __r._M_append(_M_pop());
 321           _M_stack.push(__r);
 322         }
 323       else if (_M_match_token(_ScannerT::_S_token_subexpr_begin))
 324         {
 325           _StateSeqT __r(_M_nfa, _M_nfa._M_insert_subexpr_begin());
 326           this->_M_disjunction();
 327           if (!_M_match_token(_ScannerT::_S_token_subexpr_end))
 328             __throw_regex_error(regex_constants::error_paren);
 329           __r._M_append(_M_pop());
 330           __r._M_append(_M_nfa._M_insert_subexpr_end());
 331           _M_stack.push(__r);
 332         }
 333       else if (!_M_bracket_expression())
 334         return false;
 335       return true;
 336     }
 337
 338   template<typename _TraitsT>
 339     bool
 340     _Compiler<_TraitsT>::
 341     _M_bracket_expression()
 342     {
 343       bool __neg =
 344         _M_match_token(_ScannerT::_S_token_bracket_neg_begin);
 345       if (!(__neg || _M_match_token(_ScannerT::_S_token_bracket_begin)))
 346         return false;
 347       __INSERT_REGEX_MATCHER(_M_insert_bracket_matcher, __neg);
 348       return true;
 349     }
 350 #undef __INSERT_REGEX_MATCHER
 351
 352   template<typename _TraitsT>
 353   template<bool __icase, bool __collate>
 354     void
 355     _Compiler<_TraitsT>::
 356     _M_insert_any_matcher_ecma()
 357     {
 358       _M_stack.push(_StateSeqT(_M_nfa,
 359         _M_nfa._M_insert_matcher
 360           (_AnyMatcher<_TraitsT, true, __icase, __collate>
 361             (_M_traits))));
 362     }
 363
 364   template<typename _TraitsT>
 365   template<bool __icase, bool __collate>
 366     void
 367     _Compiler<_TraitsT>::
 368     _M_insert_any_matcher_posix()
 369     {
 370       _M_stack.push(_StateSeqT(_M_nfa,
 371         _M_nfa._M_insert_matcher
 372           (_AnyMatcher<_TraitsT, false, __icase, __collate>
 373             (_M_traits))));
 374     }
 375
 376   template<typename _TraitsT>
 377   template<bool __icase, bool __collate>
 378     void
 379     _Compiler<_TraitsT>::
 380     _M_insert_char_matcher()
 381     {
 382       _M_stack.push(_StateSeqT(_M_nfa,
 383         _M_nfa._M_insert_matcher
 384           (_CharMatcher<_TraitsT, __icase, __collate>
 385             (_M_value[0], _M_traits))));
 386     }
 387
 388   template<typename _TraitsT>
 389   template<bool __icase, bool __collate>
 390     void
 391     _Compiler<_TraitsT>::
 392     _M_insert_character_class_matcher()
 393     {
 394       _GLIBCXX_DEBUG_ASSERT(_M_value.size() == 1);
 395       _BracketMatcher<_TraitsT, __icase, __collate> __matcher
 396         (_M_ctype.is(_CtypeT::upper, _M_value[0]), _M_traits);
 397       __matcher._M_add_character_class(_M_value);
 398       __matcher._M_ready();
 399       _M_stack.push(_StateSeqT(_M_nfa,
 400         _M_nfa._M_insert_matcher(std::move(__matcher))));
 401     }
 402
 403   template<typename _TraitsT>
 404   template<bool __icase, bool __collate>
 405     void
 406     _Compiler<_TraitsT>::
 407     _M_insert_bracket_matcher(bool __neg)
 408     {
 409       _BracketMatcher<_TraitsT, __icase, __collate> __matcher(__neg, _M_traits);
 410       while (!_M_match_token(_ScannerT::_S_token_bracket_end))
 411         _M_expression_term(__matcher);
 412       __matcher._M_ready();
 413       _M_stack.push(_StateSeqT(_M_nfa,
 414                                _M_nfa._M_insert_matcher(std::move(__matcher))));
 415     }
 416
 417   template<typename _TraitsT>
 418   template<bool __icase, bool __collate>
 419     void
 420     _Compiler<_TraitsT>::
 421     _M_expression_term(_BracketMatcher<_TraitsT, __icase, __collate>& __matcher)
 422     {
 423       if (_M_match_token(_ScannerT::_S_token_collsymbol))
 424         __matcher._M_add_collating_element(_M_value);
 425       else if (_M_match_token(_ScannerT::_S_token_equiv_class_name))
 426         __matcher._M_add_equivalence_class(_M_value);
 427       else if (_M_match_token(_ScannerT::_S_token_char_class_name))
 428         __matcher._M_add_character_class(_M_value);
 429       else if (_M_try_char()) // [a
 430         {
 431           auto __ch = _M_value[0];
 432           if (_M_try_char())
 433             {
 434               if (_M_value[0] == '-') // [a-
 435                 {
 436                   if (_M_try_char()) // [a-z]
 437                     {
 438                       __matcher._M_make_range(__ch, _M_value[0]);
 439                       return;
 440                     }
 441                   // If the dash is the last character in the bracket
 442                   // expression, it is not special.
 443                   if (_M_scanner._M_get_token()
 444                       != _ScannerT::_S_token_bracket_end)
 445                     __throw_regex_error(regex_constants::error_range);
 446                 }
 447               __matcher._M_add_char(_M_value[0]);
 448             }
 449           __matcher._M_add_char(__ch);
 450         }
 451       else
 452         __throw_regex_error(regex_constants::error_brack);
 453     }
 454
 455   template<typename _TraitsT>
 456     bool
 457     _Compiler<_TraitsT>::
 458     _M_try_char()
 459     {
 460       bool __is_char = false;
 461       if (_M_match_token(_ScannerT::_S_token_oct_num))
 462         {
 463           __is_char = true;
 464           _M_value.assign(1, _M_cur_int_value(8));
 465         }
 466       else if (_M_match_token(_ScannerT::_S_token_hex_num))
 467         {
 468           __is_char = true;
 469           _M_value.assign(1, _M_cur_int_value(16));
 470         }
 471       else if (_M_match_token(_ScannerT::_S_token_ord_char))
 472         __is_char = true;
 473       return __is_char;
 474     }
 475
 476   template<typename _TraitsT>
 477     bool
 478     _Compiler<_TraitsT>::
 479     _M_match_token(_TokenT token)
 480     {
 481       if (token == _M_scanner._M_get_token())
 482         {
 483           _M_value = _M_scanner._M_get_value();
 484           _M_scanner._M_advance();
 485           return true;
 486         }
 487       return false;
 488     }
 489
 490   template<typename _TraitsT>
 491     int
 492     _Compiler<_TraitsT>::
 493     _M_cur_int_value(int __radix)
 494     {
 495       long __v = 0;
 496       for (typename _StringT::size_type __i = 0;
 497            __i < _M_value.length(); ++__i)
 498         __v =__v * __radix + _M_traits.value(_M_value[__i], __radix);
 499       return __v;
 500     }
 501
 502   template<typename _TraitsT, bool __icase, bool __collate>
 503     bool
 504     _BracketMatcher<_TraitsT, __icase, __collate>::
 505     _M_apply(_CharT __ch, false_type) const
 506     {
 507       bool __ret = false;
 508       if (std::find(_M_char_set.begin(), _M_char_set.end(),
 509                     _M_translator._M_translate(__ch))
 510           != _M_char_set.end())
 511         __ret = true;
 512       else
 513         {
 514           auto __s = _M_translator._M_transform(__ch);
 515           for (auto& __it : _M_range_set)
 516             if (__it.first <= __s && __s <= __it.second)
 517               {
 518                 __ret = true;
 519                 break;
 520               }
 521           if (_M_traits.isctype(__ch, _M_class_set))
 522             __ret = true;
 523           else if (std::find(_M_equiv_set.begin(), _M_equiv_set.end(),
 524                              _M_traits.transform_primary(&__ch, &__ch+1))
 525                    != _M_equiv_set.end())
 526             __ret = true;
 527         }
 528       if (_M_is_non_matching)
 529         return !__ret;
 530       else
 531         return __ret;
 532     }
 533
 534 _GLIBCXX_END_NAMESPACE_VERSION
 535 } // namespace __detail
 536 } // namespace