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Edit File: regex_executor.h

// class template regex -*- C++ -*- // Copyright (C) 2013-2021 Free Software Foundation, Inc. // // This file is part of the GNU ISO C++ Library. This library is free // software; you can redistribute it and/or modify it under the // terms of the GNU General Public License as published by the // Free Software Foundation; either version 3, or (at your option) // any later version. // This library is distributed in the hope that it will be useful, // but WITHOUT ANY WARRANTY; without even the implied warranty of // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the // GNU General Public License for more details. // Under Section 7 of GPL version 3, you are granted additional // permissions described in the GCC Runtime Library Exception, version // 3.1, as published by the Free Software Foundation. // You should have received a copy of the GNU General Public License and // a copy of the GCC Runtime Library Exception along with this program; // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see // <http://www.gnu.org/licenses/>. /** * @file bits/regex_executor.h * This is an internal header file, included by other library headers. * Do not attempt to use it directly. @headername{regex} */ // FIXME convert comments to doxygen format. namespace std _GLIBCXX_VISIBILITY(default) { _GLIBCXX_BEGIN_NAMESPACE_VERSION namespace __detail { /** * @addtogroup regex-detail * @{ */ /** * @brief Takes a regex and an input string and does the matching. * * The %_Executor class has two modes: DFS mode and BFS mode, controlled * by the template parameter %__dfs_mode. */ template<typename _BiIter, typename _Alloc, typename _TraitsT, bool __dfs_mode> class _Executor { using __search_mode = integral_constant<bool, __dfs_mode>; using __dfs = true_type; using __bfs = false_type; enum class _Match_mode : unsigned char { _Exact, _Prefix }; public: typedef typename iterator_traits<_BiIter>::value_type _CharT; typedef basic_regex<_CharT, _TraitsT> _RegexT; typedef std::vector<sub_match<_BiIter>, _Alloc> _ResultsVec; typedef regex_constants::match_flag_type _FlagT; typedef typename _TraitsT::char_class_type _ClassT; typedef _NFA<_TraitsT> _NFAT; public: _Executor(_BiIter __begin, _BiIter __end, _ResultsVec& __results, const _RegexT& __re, _FlagT __flags) : _M_begin(__begin), _M_end(__end), _M_re(__re), _M_nfa(*__re._M_automaton), _M_results(__results), _M_rep_count(_M_nfa.size()), _M_states(_M_nfa._M_start(), _M_nfa.size()), _M_flags(__flags) { using namespace regex_constants; if (__flags & match_prev_avail) // ignore not_bol and not_bow _M_flags &= ~(match_not_bol | match_not_bow); } // Set matched when string exactly matches the pattern. bool _M_match() { _M_current = _M_begin; return _M_main(_Match_mode::_Exact); } // Set matched when some prefix of the string matches the pattern. bool _M_search_from_first() { _M_current = _M_begin; return _M_main(_Match_mode::_Prefix); } bool _M_search(); private: void _M_rep_once_more(_Match_mode __match_mode, _StateIdT); void _M_handle_repeat(_Match_mode, _StateIdT); void _M_handle_subexpr_begin(_Match_mode, _StateIdT); void _M_handle_subexpr_end(_Match_mode, _StateIdT); void _M_handle_line_begin_assertion(_Match_mode, _StateIdT); void _M_handle_line_end_assertion(_Match_mode, _StateIdT); void _M_handle_word_boundary(_Match_mode, _StateIdT); void _M_handle_subexpr_lookahead(_Match_mode, _StateIdT); void _M_handle_match(_Match_mode, _StateIdT); void _M_handle_backref(_Match_mode, _StateIdT); void _M_handle_accept(_Match_mode, _StateIdT); void _M_handle_alternative(_Match_mode, _StateIdT); void _M_dfs(_Match_mode __match_mode, _StateIdT __start); bool _M_main(_Match_mode __match_mode) { return _M_main_dispatch(__match_mode, __search_mode{}); } bool _M_main_dispatch(_Match_mode __match_mode, __dfs); bool _M_main_dispatch(_Match_mode __match_mode, __bfs); bool _M_is_word(_CharT __ch) const { static const _CharT __s[2] = { 'w' }; return _M_re._M_automaton->_M_traits.isctype (__ch, _M_re._M_automaton->_M_traits.lookup_classname(__s, __s+1)); } bool _M_at_begin() const { if (_M_current == _M_begin) { // match_not_bol means ^ does not match [_M_begin,_M_begin) if (_M_flags & regex_constants::match_not_bol) return false; // match_prev_avail means _M_begin is not the start of the input. if (_M_flags & regex_constants::match_prev_avail) { // For ECMAScript multiline matches, check if the previous // character is a line terminator. if (_M_match_multiline()) return _M_is_line_terminator(*std::prev(_M_current)); else return false; } else // ^ matches at _M_begin return true; } else if (_M_match_multiline()) return _M_is_line_terminator(*std::prev(_M_current)); else return false; } bool _M_at_end() const { if (_M_current == _M_end) return !(_M_flags & regex_constants::match_not_eol); else if (_M_match_multiline()) return _M_is_line_terminator(*_M_current); else return false; } bool _M_word_boundary() const; bool _M_lookahead(_StateIdT __next); bool _M_is_line_terminator(_CharT __c) const { const auto& __traits = _M_re._M_automaton->_M_traits; const auto& __ct = use_facet<ctype<_CharT>>(__traits.getloc()); const char __n{ __ct.narrow(__c, ' ') }; if (__n == '\n') return true; if (_M_re._M_automaton->_M_options() & regex_constants::ECMAScript) { if (__n == '\r') return true; // FIXME: U+2028 (line separator) and U+2029 (paragraph separator) } return false; } bool _M_match_multiline() const noexcept { constexpr auto __m = regex_constants::ECMAScript | regex_constants::__multiline; return (_M_re._M_automaton->_M_options() & __m) == __m; } // Holds additional information used in BFS-mode. template<typename _SearchMode, typename _ResultsVec> struct _State_info; template<typename _ResultsVec> struct _State_info<__bfs, _ResultsVec> { explicit _State_info(_StateIdT __start, size_t __n) : _M_visited_states(new bool[__n]()), _M_start(__start) { } bool _M_visited(_StateIdT __i) { if (_M_visited_states[__i]) return true; _M_visited_states[__i] = true; return false; } void _M_queue(_StateIdT __i, const _ResultsVec& __res) { _M_match_queue.emplace_back(__i, __res); } // Dummy implementations for BFS mode. _BiIter* _M_get_sol_pos() { return nullptr; } // Saves states that need to be considered for the next character. vector<pair<_StateIdT, _ResultsVec>> _M_match_queue; // Indicates which states are already visited. unique_ptr<bool[]> _M_visited_states; // To record current solution. _StateIdT _M_start; }; template<typename _ResultsVec> struct _State_info<__dfs, _ResultsVec> { explicit _State_info(_StateIdT __start, size_t) : _M_start(__start) { } // Dummy implementations for DFS mode. bool _M_visited(_StateIdT) const { return false; } void _M_queue(_StateIdT, const _ResultsVec&) { } _BiIter* _M_get_sol_pos() { return &_M_sol_pos; } // To record current solution. _StateIdT _M_start; _BiIter _M_sol_pos; }; public: _ResultsVec _M_cur_results; _BiIter _M_current; _BiIter _M_begin; const _BiIter _M_end; const _RegexT& _M_re; const _NFAT& _M_nfa; _ResultsVec& _M_results; vector<pair<_BiIter, int>> _M_rep_count; _State_info<__search_mode, _ResultsVec> _M_states; _FlagT _M_flags; // Do we have a solution so far? bool _M_has_sol; }; ///@} regex-detail } // namespace __detail _GLIBCXX_END_NAMESPACE_VERSION } // namespace std #include <bits/regex_executor.tcc>