libstdc++

regex_grep_matcher.tcc
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1 // class template regex -*- C++ -*-
2
3 // Copyright (C) 2010-2013 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_grep_matcher.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 #include <regex>
32
33 namespace std _GLIBCXX_VISIBILITY(default)
34 {
35 namespace
36 {
37 // A stack of states used in evaluating the NFA.
38 typedef std::stack<std::__detail::_StateIdT,
39 std::vector<std::__detail::_StateIdT>
40 > _StateStack;
41
42 // Obtains the next state set given the current state set __s and the current
43 // input character.
44 inline std::__detail::_StateSet
45 __move(const std::__detail::_PatternCursor& __p,
46 const std::__detail::_Nfa& __nfa,
47 const std::__detail::_StateSet& __s)
48 {
49 std::__detail::_StateSet __m;
50 for (std::__detail::_StateSet::const_iterator __i = __s.begin();
51 __i != __s.end(); ++__i)
52 {
53 if (*__i == std::__detail::_S_invalid_state_id)
54 continue;
55
56 const std::__detail::_State& __state = __nfa[*__i];
57 if (__state._M_opcode == std::__detail::_S_opcode_match
58 && __state._M_matches(__p))
59 __m.insert(__state._M_next);
60 }
61 return __m;
62 }
63
64 // returns true if (__s intersect __t) is not empty
65 inline bool
66 __includes_some(const std::__detail::_StateSet& __s,
67 const std::__detail::_StateSet& __t)
68 {
69 if (__s.size() > 0 && __t.size() > 0)
70 {
71 std::__detail::_StateSet::const_iterator __first = __s.begin();
72 std::__detail::_StateSet::const_iterator __second = __t.begin();
73 while (__first != __s.end() && __second != __t.end())
74 {
75 if (*__first < *__second)
76 ++__first;
77 else if (*__second < *__first)
78 ++__second;
79 else
80 return true;
81 }
82 }
83 return false;
84 }
85
86 // If an identified state __u is not already in the current state set __e,
87 // insert it and push it on the current state stack __s.
88 inline void
89 __add_visited_state(const std::__detail::_StateIdT __u,
90 _StateStack& __s,
91 std::__detail::_StateSet& __e)
92 {
93 if (__e.count(__u) == 0)
94 {
95 __e.insert(__u);
96 __s.push(__u);
97 }
98 }
99
100 } // anonymous namespace
101
102 namespace __detail
103 {
104 _GLIBCXX_BEGIN_NAMESPACE_VERSION
105
106 inline _Grep_matcher::
107 _Grep_matcher(_PatternCursor& __p, _Results& __r,
108 const _AutomatonPtr& __nfa,
109 regex_constants::match_flag_type __flags)
110 : _M_nfa(static_pointer_cast<_Nfa>(__nfa)), _M_pattern(__p), _M_results(__r)
111 {
112 __detail::_StateSet __t = this->_M_e_closure(_M_nfa->_M_start());
113 for (; !_M_pattern._M_at_end(); _M_pattern._M_next())
114 __t = this->_M_e_closure(__move(_M_pattern, *_M_nfa, __t));
115
116 _M_results._M_set_matched(0,
117 __includes_some(_M_nfa->_M_final_states(), __t));
118 }
119
120 // Creates the e-closure set for the initial state __i.
121 inline _StateSet _Grep_matcher::
122 _M_e_closure(_StateIdT __i)
123 {
124 _StateSet __s;
125 __s.insert(__i);
126 _StateStack __stack;
127 __stack.push(__i);
128 return this->_M_e_closure(__stack, __s);
129 }
130
131 // Creates the e-closure set for an arbitrary state set __s.
132 inline _StateSet _Grep_matcher::
133 _M_e_closure(const _StateSet& __s)
134 {
135 _StateStack __stack;
136 for (_StateSet::const_iterator __i = __s.begin(); __i != __s.end(); ++__i)
137 __stack.push(*__i);
138 return this->_M_e_closure(__stack, __s);
139 }
140
141 inline _StateSet _Grep_matcher::
142 _M_e_closure(_StateStack& __stack, const _StateSet& __s)
143 {
144 _StateSet __e = __s;
145 while (!__stack.empty())
146 {
147 _StateIdT __t = __stack.top(); __stack.pop();
148 if (__t == _S_invalid_state_id)
149 continue;
150 // for each __u with edge from __t to __u labeled e do ...
151 const _State& __state = _M_nfa->operator[](__t);
152 switch (__state._M_opcode)
153 {
154 case _S_opcode_alternative:
155 __add_visited_state(__state._M_next, __stack, __e);
156 __add_visited_state(__state._M_alt, __stack, __e);
157 break;
158 case _S_opcode_subexpr_begin:
159 __add_visited_state(__state._M_next, __stack, __e);
160 __state._M_tagger(_M_pattern, _M_results);
161 break;
162 case _S_opcode_subexpr_end:
163 __add_visited_state(__state._M_next, __stack, __e);
164 __state._M_tagger(_M_pattern, _M_results);
165 _M_results._M_set_matched(__state._M_subexpr, true);
166 break;
167 case _S_opcode_accept:
168 __add_visited_state(__state._M_next, __stack, __e);
169 break;
170 default:
171 break;
172 }
173 }
174 return __e;
175 }
176
177 _GLIBCXX_END_NAMESPACE_VERSION
178 } // namespace __detail
179 } // namespace