regex_automaton.tcc 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_automaton.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	namespace std _GLIBCXX_VISIBILITY(default)
32	{
33	namespace __detail
34	{
35	_GLIBCXX_BEGIN_NAMESPACE_VERSION
36
37	#ifdef _GLIBCXX_DEBUG
38	inline std::ostream&
39	_State_base::_M_print(std::ostream& ostr) const
40	{
41	switch (_M_opcode)
42	{
43	case _S_opcode_alternative:
44	case _S_opcode_repeat:
45	ostr << "alt next=" << _M_next << " alt=" << _M_alt;
46	break;
47	case _S_opcode_subexpr_begin:
48	ostr << "subexpr begin next=" << _M_next << " index=" << _M_subexpr;
49	break;
50	case _S_opcode_subexpr_end:
51	ostr << "subexpr end next=" << _M_next << " index=" << _M_subexpr;
52	break;
53	case _S_opcode_backref:
54	ostr << "backref next=" << _M_next << " index=" << _M_backref_index;
55	break;
56	case _S_opcode_match:
57	ostr << "match next=" << _M_next;
58	break;
59	case _S_opcode_accept:
60	ostr << "accept next=" << _M_next;
61	break;
62	default:
63	ostr << "unknown next=" << _M_next;
64	break;
65	}
66	return ostr;
67	}
68
69	// Prints graphviz dot commands for state.
70	inline std::ostream&
71	_State_base::_M_dot(std::ostream& __ostr, _StateIdT __id) const
72	{
73	switch (_M_opcode)
74	{
75	case _S_opcode_alternative:
76	case _S_opcode_repeat:
77	__ostr << __id << " [label=\"" << __id << "\\nALT\"];\n"
78	<< __id << " -> " << _M_next
79	<< " [label=\"next\", tailport=\"s\"];\n"
80	<< __id << " -> " << _M_alt
81	<< " [label=\"alt\", tailport=\"n\"];\n";
82	break;
83	case _S_opcode_backref:
84	__ostr << __id << " [label=\"" << __id << "\\nBACKREF "
85	<< _M_subexpr << "\"];\n"
86	<< __id << " -> " << _M_next << " [label=\"<match>\"];\n";
87	break;
88	case _S_opcode_line_begin_assertion:
89	__ostr << __id << " [label=\"" << __id << "\\nLINE_BEGIN \"];\n"
90	<< __id << " -> " << _M_next << " [label=\"epsilon\"];\n";
91	break;
92	case _S_opcode_line_end_assertion:
93	__ostr << __id << " [label=\"" << __id << "\\nLINE_END \"];\n"
94	<< __id << " -> " << _M_next << " [label=\"epsilon\"];\n";
95	break;
96	case _S_opcode_word_boundary:
97	__ostr << __id << " [label=\"" << __id << "\\nWORD_BOUNDRY "
98	<< _M_neg << "\"];\n"
99	<< __id << " -> " << _M_next << " [label=\"epsilon\"];\n";
100	break;
101	case _S_opcode_subexpr_lookahead:
102	__ostr << __id << " [label=\"" << __id << "\\nLOOK_AHEAD\"];\n"
103	<< __id << " -> " << _M_next
104	<< " [label=\"epsilon\", tailport=\"s\"];\n"
105	<< __id << " -> " << _M_alt
106	<< " [label=\"<assert>\", tailport=\"n\"];\n";
107	break;
108	case _S_opcode_subexpr_begin:
109	__ostr << __id << " [label=\"" << __id << "\\nSBEGIN "
110	<< _M_subexpr << "\"];\n"
111	<< __id << " -> " << _M_next << " [label=\"epsilon\"];\n";
112	break;
113	case _S_opcode_subexpr_end:
114	__ostr << __id << " [label=\"" << __id << "\\nSEND "
115	<< _M_subexpr << "\"];\n"
116	<< __id << " -> " << _M_next << " [label=\"epsilon\"];\n";
117	break;
118	case _S_opcode_dummy:
119	break;
120	case _S_opcode_match:
121	__ostr << __id << " [label=\"" << __id << "\\nMATCH\"];\n"
122	<< __id << " -> " << _M_next << " [label=\"<match>\"];\n";
123	break;
124	case _S_opcode_accept:
125	__ostr << __id << " [label=\"" << __id << "\\nACC\"];\n" ;
126	break;
127	default:
128	_GLIBCXX_DEBUG_ASSERT(false);
129	break;
130	}
131	return __ostr;
132	}
133
134	template<typename _TraitsT>
135	std::ostream&
136	_NFA<_TraitsT>::_M_dot(std::ostream& __ostr) const
137	{
138	__ostr << "digraph _Nfa {\n"
139	" rankdir=LR;\n";
140	for (size_t __i = 0; __i < this->size(); ++__i)
141	(*this)[__i]._M_dot(__ostr, __i);
142	__ostr << "}\n";
143	return __ostr;
144	}
145	#endif
146
147	template<typename _TraitsT>
148	_StateIdT
149	_NFA<_TraitsT>::_M_insert_backref(size_t __index)
150	{
151	if (this->_M_flags & regex_constants::__polynomial)
152	__throw_regex_error(regex_constants::error_complexity,
153	"Unexpected back-reference in polynomial mode.");
154	// To figure out whether a backref is valid, a stack is used to store
155	// unfinished sub-expressions. For example, when parsing
156	// "(a(b)(c\\1(d)))" at '\\1', _M_subexpr_count is 3, indicating that 3
157	// sub expressions are parsed or partially parsed(in the stack), aka,
158	// "(a..", "(b)" and "(c..").
159	// _M_paren_stack is {1, 3}, for incomplete "(a.." and "(c..". At this
160	// time, "\\2" is valid, but "\\1" and "\\3" are not.
161	if (__index >= _M_subexpr_count)
162	__throw_regex_error(
163	regex_constants::error_backref,
164	"Back-reference index exceeds current sub-expression count.");
165	for (auto __it : this->_M_paren_stack)
166	if (__index == __it)
167	__throw_regex_error(
168	regex_constants::error_backref,
169	"Back-reference referred to an opened sub-expression.");
170	this->_M_has_backref = true;
171	_StateT __tmp(_S_opcode_backref);
172	__tmp._M_backref_index = __index;
173	return _M_insert_state(std::move(__tmp));
174	}
175
176	template<typename _TraitsT>
177	void
178	_NFA<_TraitsT>::_M_eliminate_dummy()
179	{
180	for (auto& __it : *this)
181	{
182	while (__it._M_next >= 0 && (*this)[__it._M_next]._M_opcode()
183	== _S_opcode_dummy)
184	__it._M_next = (*this)[__it._M_next]._M_next;
185	if (__it._M_has_alt())
186	while (__it._M_alt >= 0 && (*this)[__it._M_alt]._M_opcode()
187	== _S_opcode_dummy)
188	__it._M_alt = (*this)[__it._M_alt]._M_next;
189	}
190	}
191
192	// Just apply DFS on the sequence and re-link their links.
193	template<typename _TraitsT>
194	_StateSeq<_TraitsT>
195	_StateSeq<_TraitsT>::_M_clone()
196	{
197	std::map<_StateIdT, _StateIdT> __m;
198	std::stack<_StateIdT> __stack;
199	__stack.push(_M_start);
200	while (!__stack.empty())
201	{
202	auto __u = __stack.top();
203	__stack.pop();
204	auto __dup = _M_nfa[__u];
205	// _M_insert_state() never return -1
206	auto __id = _M_nfa._M_insert_state(std::move(__dup));
207	__m[__u] = __id;
208	if (__dup._M_has_alt())
209	if (__dup._M_alt != _S_invalid_state_id
210	&& __m.count(__dup._M_alt) == 0)
211	__stack.push(__dup._M_alt);
212	if (__u == _M_end)
213	continue;
214	if (__dup._M_next != _S_invalid_state_id
215	&& __m.count(__dup._M_next) == 0)
216	__stack.push(__dup._M_next);
217	}
218	for (auto __it : __m)
219	{
220	auto __v = __it.second;
221	auto& __ref = _M_nfa[__v];
222	if (__ref._M_next != _S_invalid_state_id)
223	{
224	__glibcxx_assert(__m.count(__ref._M_next) > 0);
225	__ref._M_next = __m[__ref._M_next];
226	}
227	if (__ref._M_has_alt())
228	if (__ref._M_alt != _S_invalid_state_id)
229	{
230	__glibcxx_assert(__m.count(__ref._M_alt) > 0);
231	__ref._M_alt = __m[__ref._M_alt];
232	}
233	}
234	return _StateSeq(_M_nfa, __m[_M_start], __m[_M_end]);
235	}
236
237	_GLIBCXX_END_NAMESPACE_VERSION
238	} // namespace __detail
239	} // namespace
240

std::__detail::_NFA::_M_insert_backref

std::__detail::_NFA::_M_eliminate_dummy

std::__detail::_StateSeq::_M_clone

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