// class template regex -*- C++ -*- // Copyright (C) 2013-2020 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_automaton.h * This is an internal header file, included by other library headers. * Do not attempt to use it directly. @headername{regex} */ // This macro defines the maximal state number a NFA can have. #ifndef _GLIBCXX_REGEX_STATE_LIMIT #define _GLIBCXX_REGEX_STATE_LIMIT 100000 #endif namespace std _GLIBCXX_VISIBILITY(default) { _GLIBCXX_BEGIN_NAMESPACE_VERSION namespace __detail { /** * @defgroup regex-detail Base and Implementation Classes * @ingroup regex * @{ */ typedef long _StateIdT; static const _StateIdT _S_invalid_state_id = -1; template<typename _CharT> using _Matcher = std::function<bool (_CharT)>; /// Operation codes that define the type of transitions within the base NFA /// that represents the regular expression. enum _Opcode : int { _S_opcode_unknown, _S_opcode_alternative, _S_opcode_repeat, _S_opcode_backref, _S_opcode_line_begin_assertion, _S_opcode_line_end_assertion, _S_opcode_word_boundary, _S_opcode_subexpr_lookahead, _S_opcode_subexpr_begin, _S_opcode_subexpr_end, _S_opcode_dummy, _S_opcode_match, _S_opcode_accept, }; struct _State_base { protected: _Opcode _M_opcode; // type of outgoing transition public: _StateIdT _M_next; // outgoing transition union // Since they are mutually exclusive. { size_t _M_subexpr; // for _S_opcode_subexpr_* size_t _M_backref_index; // for _S_opcode_backref struct { // for _S_opcode_alternative, _S_opcode_repeat and // _S_opcode_subexpr_lookahead _StateIdT _M_alt; // for _S_opcode_word_boundary or _S_opcode_subexpr_lookahead or // quantifiers (ungreedy if set true) bool _M_neg; }; // For _S_opcode_match __gnu_cxx::__aligned_membuf<_Matcher<char>> _M_matcher_storage; }; protected: explicit _State_base(_Opcode __opcode) : _M_opcode(__opcode), _M_next(_S_invalid_state_id) { } public: bool _M_has_alt() { return _M_opcode == _S_opcode_alternative || _M_opcode == _S_opcode_repeat || _M_opcode == _S_opcode_subexpr_lookahead; } #ifdef _GLIBCXX_DEBUG std::ostream& _M_print(std::ostream& ostr) const; // Prints graphviz dot commands for state. std::ostream& _M_dot(std::ostream& __ostr, _StateIdT __id) const; #endif }; template<typename _Char_type> struct _State : _State_base { typedef _Matcher<_Char_type> _MatcherT; static_assert(sizeof(_MatcherT) == sizeof(_Matcher<char>), "std::function<bool(T)> has the same size as " "std::function<bool(char)>"); static_assert(alignof(_MatcherT) == alignof(_Matcher<char>), "std::function<bool(T)> has the same alignment as " "std::function<bool(char)>"); explicit _State(_Opcode __opcode) : _State_base(__opcode) { if (_M_opcode() == _S_opcode_match) new (this->_M_matcher_storage._M_addr()) _MatcherT(); } _State(const _State& __rhs) : _State_base(__rhs) { if (__rhs._M_opcode() == _S_opcode_match) new (this->_M_matcher_storage._M_addr()) _MatcherT(__rhs._M_get_matcher()); } _State(_State&& __rhs) : _State_base(__rhs) { if (__rhs._M_opcode() == _S_opcode_match) new (this->_M_matcher_storage._M_addr()) _MatcherT(std::move(__rhs._M_get_matcher())); } _State& operator=(const _State&) = delete; ~_State() { if (_M_opcode() == _S_opcode_match) _M_get_matcher().~_MatcherT(); } // Since correct ctor and dtor rely on _M_opcode, it's better not to // change it over time. _Opcode _M_opcode() const { return _State_base::_M_opcode; } bool _M_matches(_Char_type __char) const { return _M_get_matcher()(__char); } _MatcherT& _M_get_matcher() { return *static_cast<_MatcherT*>(this->_M_matcher_storage._M_addr()); } const _MatcherT& _M_get_matcher() const { return *static_cast<const _MatcherT*>( this->_M_matcher_storage._M_addr()); } }; struct _NFA_base { typedef size_t _SizeT; typedef regex_constants::syntax_option_type _FlagT; explicit _NFA_base(_FlagT __f) : _M_flags(__f), _M_start_state(0), _M_subexpr_count(0), _M_has_backref(false) { } _NFA_base(_NFA_base&&) = default; protected: ~_NFA_base() = default; public: _FlagT _M_options() const { return _M_flags; } _StateIdT _M_start() const { return _M_start_state; } _SizeT _M_sub_count() const { return _M_subexpr_count; } _GLIBCXX_STD_C::vector<size_t> _M_paren_stack; _FlagT _M_flags; _StateIdT _M_start_state; _SizeT _M_subexpr_count; bool _M_has_backref; }; template<typename _TraitsT> struct _NFA : _NFA_base, _GLIBCXX_STD_C::vector<_State<typename _TraitsT::char_type>> { typedef typename _TraitsT::char_type _Char_type; typedef _State<_Char_type> _StateT; typedef _Matcher<_Char_type> _MatcherT; _NFA(const typename _TraitsT::locale_type& __loc, _FlagT __flags) : _NFA_base(__flags) { _M_traits.imbue(__loc); } // for performance reasons _NFA objects should only be moved not copied _NFA(const _NFA&) = delete; _NFA(_NFA&&) = default; _StateIdT _M_insert_accept() { auto __ret = _M_insert_state(_StateT(_S_opcode_accept)); return __ret; } _StateIdT _M_insert_alt(_StateIdT __next, _StateIdT __alt, bool __neg __attribute__((__unused__))) { _StateT __tmp(_S_opcode_alternative); // It labels every quantifier to make greedy comparison easier in BFS // approach. __tmp._M_next = __next; __tmp._M_alt = __alt; return _M_insert_state(std::move(__tmp)); } _StateIdT _M_insert_repeat(_StateIdT __next, _StateIdT __alt, bool __neg) { _StateT __tmp(_S_opcode_repeat); // It labels every quantifier to make greedy comparison easier in BFS // approach. __tmp._M_next = __next; __tmp._M_alt = __alt; __tmp._M_neg = __neg; return _M_insert_state(std::move(__tmp)); } _StateIdT _M_insert_matcher(_MatcherT __m) { _StateT __tmp(_S_opcode_match); __tmp._M_get_matcher() = std::move(__m); return _M_insert_state(std::move(__tmp)); } _StateIdT _M_insert_subexpr_begin() { auto __id = this->_M_subexpr_count++; this->_M_paren_stack.push_back(__id); _StateT __tmp(_S_opcode_subexpr_begin); __tmp._M_subexpr = __id; return _M_insert_state(std::move(__tmp)); } _StateIdT _M_insert_subexpr_end() { _StateT __tmp(_S_opcode_subexpr_end); __tmp._M_subexpr = this->_M_paren_stack.back(); this->_M_paren_stack.pop_back(); return _M_insert_state(std::move(__tmp)); } _StateIdT _M_insert_backref(size_t __index); _StateIdT _M_insert_line_begin() { return _M_insert_state(_StateT(_S_opcode_line_begin_assertion)); } _StateIdT _M_insert_line_end() { return _M_insert_state(_StateT(_S_opcode_line_end_assertion)); } _StateIdT _M_insert_word_bound(bool __neg) { _StateT __tmp(_S_opcode_word_boundary); __tmp._M_neg = __neg; return _M_insert_state(std::move(__tmp)); } _StateIdT _M_insert_lookahead(_StateIdT __alt, bool __neg) { _StateT __tmp(_S_opcode_subexpr_lookahead); __tmp._M_alt = __alt; __tmp._M_neg = __neg; return _M_insert_state(std::move(__tmp)); } _StateIdT _M_insert_dummy() { return _M_insert_state(_StateT(_S_opcode_dummy)); } _StateIdT _M_insert_state(_StateT __s) { this->push_back(std::move(__s)); if (this->size() > _GLIBCXX_REGEX_STATE_LIMIT) __throw_regex_error( regex_constants::error_space, "Number of NFA states exceeds limit. Please use shorter regex " "string, or use smaller brace expression, or make " "_GLIBCXX_REGEX_STATE_LIMIT larger."); return this->size() - 1; } // Eliminate dummy node in this NFA to make it compact. void _M_eliminate_dummy(); #ifdef _GLIBCXX_DEBUG std::ostream& _M_dot(std::ostream& __ostr) const; #endif public: _TraitsT _M_traits; }; /// Describes a sequence of one or more %_State, its current start /// and end(s). This structure contains fragments of an NFA during /// construction. template<typename _TraitsT> class _StateSeq { public: typedef _NFA<_TraitsT> _RegexT; public: _StateSeq(_RegexT& __nfa, _StateIdT __s) : _M_nfa(__nfa), _M_start(__s), _M_end(__s) { } _StateSeq(_RegexT& __nfa, _StateIdT __s, _StateIdT __end) : _M_nfa(__nfa), _M_start(__s), _M_end(__end) { } // Append a state on *this and change *this to the new sequence. void _M_append(_StateIdT __id) { _M_nfa[_M_end]._M_next = __id; _M_end = __id; } // Append a sequence on *this and change *this to the new sequence. void _M_append(const _StateSeq& __s) { _M_nfa[_M_end]._M_next = __s._M_start; _M_end = __s._M_end; } // Clones an entire sequence. _StateSeq _M_clone(); public: _RegexT& _M_nfa; _StateIdT _M_start; _StateIdT _M_end; }; //@} regex-detail } // namespace __detail _GLIBCXX_END_NAMESPACE_VERSION } // namespace std #include <bits/regex_automaton.tcc>