libstdc++-v3/include/bits/regex_executor.h

   1 // class template regex -*- C++ -*-
   2
   3 // Copyright (C) 2013-2016 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_executor.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 // FIXME convert comments to doxygen format.
  32
  33 namespace std _GLIBCXX_VISIBILITY(default)
  34 {
  35 namespace __detail
  36 {
  37 _GLIBCXX_BEGIN_NAMESPACE_VERSION
  38
  39   /**
  40    * @addtogroup regex-detail
  41    * @{
  42    */
  43
  44   /**
  45    * @brief Takes a regex and an input string and does the matching.
  46    *
  47    * The %_Executor class has two modes: DFS mode and BFS mode, controlled
  48    * by the template parameter %__dfs_mode.
  49    */
  50   template<typename _BiIter, typename _Alloc, typename _TraitsT,
  51            bool __dfs_mode>
  52     class _Executor
  53     {
  54       using __search_mode = integral_constant<bool, __dfs_mode>;
  55       using __dfs = true_type;
  56       using __bfs = false_type;
  57
  58       enum class _Match_mode : unsigned char { _Exact, _Prefix };
  59
  60     public:
  61       typedef typename iterator_traits<_BiIter>::value_type _CharT;
  62       typedef basic_regex<_CharT, _TraitsT>                 _RegexT;
  63       typedef std::vector<sub_match<_BiIter>, _Alloc>       _ResultsVec;
  64       typedef regex_constants::match_flag_type              _FlagT;
  65       typedef typename _TraitsT::char_class_type            _ClassT;
  66       typedef _NFA<_TraitsT>                                _NFAT;
  67
  68     public:
  69       _Executor(_BiIter         __begin,
  70                 _BiIter         __end,
  71                 _ResultsVec&    __results,
  72                 const _RegexT&  __re,
  73                 _FlagT          __flags)
  74       : _M_begin(__begin),
  75       _M_end(__end),
  76       _M_re(__re),
  77       _M_nfa(*__re._M_automaton),
  78       _M_results(__results),
  79       _M_rep_count(_M_nfa.size()),
  80       _M_states(_M_nfa._M_start(), _M_nfa.size()),
  81       _M_flags((__flags & regex_constants::match_prev_avail)
  82                ? (__flags
  83                   & ~regex_constants::match_not_bol
  84                   & ~regex_constants::match_not_bow)
  85                : __flags)
  86       { }
  87
  88       // Set matched when string exactly matches the pattern.
  89       bool
  90       _M_match()
  91       {
  92         _M_current = _M_begin;
  93         return _M_main(_Match_mode::_Exact);
  94       }
  95
  96       // Set matched when some prefix of the string matches the pattern.
  97       bool
  98       _M_search_from_first()
  99       {
 100         _M_current = _M_begin;
 101         return _M_main(_Match_mode::_Prefix);
 102       }
 103
 104       bool
 105       _M_search();
 106
 107     private:
 108       void
 109       _M_rep_once_more(_Match_mode __match_mode, _StateIdT);
 110
 111       void
 112       _M_handle_repeat(_Match_mode, _StateIdT);
 113
 114       void
 115       _M_handle_subexpr_begin(_Match_mode, _StateIdT);
 116
 117       void
 118       _M_handle_subexpr_end(_Match_mode, _StateIdT);
 119
 120       void
 121       _M_handle_line_begin_assertion(_Match_mode, _StateIdT);
 122
 123       void
 124       _M_handle_line_end_assertion(_Match_mode, _StateIdT);
 125
 126       void
 127       _M_handle_word_boundary(_Match_mode, _StateIdT);
 128
 129       void
 130       _M_handle_subexpr_lookahead(_Match_mode, _StateIdT);
 131
 132       void
 133       _M_handle_match(_Match_mode, _StateIdT);
 134
 135       void
 136       _M_handle_backref(_Match_mode, _StateIdT);
 137
 138       void
 139       _M_handle_accept(_Match_mode, _StateIdT);
 140
 141       void
 142       _M_handle_alternative(_Match_mode, _StateIdT);
 143
 144       void
 145       _M_dfs(_Match_mode __match_mode, _StateIdT __start);
 146
 147       bool
 148       _M_main(_Match_mode __match_mode)
 149       { return _M_main_dispatch(__match_mode, __search_mode{}); }
 150
 151       bool
 152       _M_main_dispatch(_Match_mode __match_mode, __dfs);
 153
 154       bool
 155       _M_main_dispatch(_Match_mode __match_mode, __bfs);
 156
 157       bool
 158       _M_is_word(_CharT __ch) const
 159       {
 160         static const _CharT __s[2] = { 'w' };
 161         return _M_re._M_automaton->_M_traits.isctype
 162           (__ch, _M_re._M_automaton->_M_traits.lookup_classname(__s, __s+1));
 163       }
 164
 165       bool
 166       _M_at_begin() const
 167       {
 168         return _M_current == _M_begin
 169           && !(_M_flags & (regex_constants::match_not_bol
 170                            | regex_constants::match_prev_avail));
 171       }
 172
 173       bool
 174       _M_at_end() const
 175       {
 176         return _M_current == _M_end
 177           && !(_M_flags & regex_constants::match_not_eol);
 178       }
 179
 180       bool
 181       _M_word_boundary() const;
 182
 183       bool
 184       _M_lookahead(_StateIdT __next);
 185
 186        // Holds additional information used in BFS-mode.
 187       template<typename _SearchMode, typename _ResultsVec>
 188         struct _State_info;
 189
 190       template<typename _ResultsVec>
 191         struct _State_info<__bfs, _ResultsVec>
 192         {
 193           explicit
 194           _State_info(_StateIdT __start, size_t __n)
 195           : _M_visited_states(new bool[__n]()), _M_start(__start)
 196           { }
 197
 198           bool _M_visited(_StateIdT __i)
 199           {
 200             if (_M_visited_states[__i])
 201               return true;
 202             _M_visited_states[__i] = true;
 203             return false;
 204           }
 205
 206           void _M_queue(_StateIdT __i, const _ResultsVec& __res)
 207           { _M_match_queue.emplace_back(__i, __res); }
 208
 209           // Dummy implementations for BFS mode.
 210           _BiIter* _M_get_sol_pos() { return nullptr; }
 211
 212           // Saves states that need to be considered for the next character.
 213           vector<pair<_StateIdT, _ResultsVec>>  _M_match_queue;
 214           // Indicates which states are already visited.
 215           unique_ptr<bool[]>                    _M_visited_states;
 216           // To record current solution.
 217           _StateIdT _M_start;
 218         };
 219
 220       template<typename _ResultsVec>
 221         struct _State_info<__dfs, _ResultsVec>
 222         {
 223           explicit
 224           _State_info(_StateIdT __start, size_t) : _M_start(__start)
 225           { }
 226
 227           // Dummy implementations for DFS mode.
 228           bool _M_visited(_StateIdT) const { return false; }
 229           void _M_queue(_StateIdT, const _ResultsVec&) { }
 230
 231           _BiIter* _M_get_sol_pos() { return &_M_sol_pos; }
 232
 233           // To record current solution.
 234           _StateIdT _M_start;
 235           _BiIter   _M_sol_pos;
 236         };
 237
 238     public:
 239       _ResultsVec                                           _M_cur_results;
 240       _BiIter                                               _M_current;
 241       _BiIter                                               _M_begin;
 242       const _BiIter                                         _M_end;
 243       const _RegexT&                                        _M_re;
 244       const _NFAT&                                          _M_nfa;
 245       _ResultsVec&                                          _M_results;
 246       vector<pair<_BiIter, int>>                            _M_rep_count;
 247       _State_info<__search_mode, _ResultsVec>               _M_states;
 248       _FlagT                                                _M_flags;
 249       // Do we have a solution so far?
 250       bool                                                  _M_has_sol;
 251     };
 252
 253  //@} regex-detail
 254 _GLIBCXX_END_NAMESPACE_VERSION
 255 } // namespace __detail
 256 } // namespace std
 257
 258 #include <bits/regex_executor.tcc>