regex_executor.h source code [include/c++/7/bits/regex

1	// class template regex -- C++ --
2
3	// Copyright (C) 2013-2017 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>
259