regex_grep_matcher.tcc
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// class template regex -*- C++ -*-
// Copyright (C) 2010-2013 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_grep_matcher.tcc
* This is an internal header file, included by other library headers.
* Do not attempt to use it directly. @headername{regex}
*/
#include <regex>
namespace std _GLIBCXX_VISIBILITY(default)
{
namespace
{
// A stack of states used in evaluating the NFA.
typedef std::stack<std::__detail::_StateIdT,
std::vector<std::__detail::_StateIdT>
> _StateStack;
// Obtains the next state set given the current state set __s and the current
// input character.
inline std::__detail::_StateSet
__move(const std::__detail::_PatternCursor& __p,
const std::__detail::_Nfa& __nfa,
const std::__detail::_StateSet& __s)
{
std::__detail::_StateSet __m;
for (std::__detail::_StateSet::const_iterator __i = __s.begin();
__i != __s.end(); ++__i)
{
if (*__i == std::__detail::_S_invalid_state_id)
continue;
const std::__detail::_State& __state = __nfa[*__i];
if (__state._M_opcode == std::__detail::_S_opcode_match
&& __state._M_matches(__p))
__m.insert(__state._M_next);
}
return __m;
}
// returns true if (__s intersect __t) is not empty
inline bool
__includes_some(const std::__detail::_StateSet& __s,
const std::__detail::_StateSet& __t)
{
if (__s.size() > 0 && __t.size() > 0)
{
std::__detail::_StateSet::const_iterator __first = __s.begin();
std::__detail::_StateSet::const_iterator __second = __t.begin();
while (__first != __s.end() && __second != __t.end())
{
if (*__first < *__second)
++__first;
else if (*__second < *__first)
++__second;
else
return true;
}
}
return false;
}
// If an identified state __u is not already in the current state set __e,
// insert it and push it on the current state stack __s.
inline void
__add_visited_state(const std::__detail::_StateIdT __u,
_StateStack& __s,
std::__detail::_StateSet& __e)
{
if (__e.count(__u) == 0)
{
__e.insert(__u);
__s.push(__u);
}
}
} // anonymous namespace
namespace __detail
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION
inline _Grep_matcher::
_Grep_matcher(_PatternCursor& __p, _Results& __r,
const _AutomatonPtr& __nfa,
regex_constants::match_flag_type __flags)
: _M_nfa(static_pointer_cast<_Nfa>(__nfa)), _M_pattern(__p), _M_results(__r)
{
__detail::_StateSet __t = this->_M_e_closure(_M_nfa->_M_start());
for (; !_M_pattern._M_at_end(); _M_pattern._M_next())
__t = this->_M_e_closure(__move(_M_pattern, *_M_nfa, __t));
_M_results._M_set_matched(0,
__includes_some(_M_nfa->_M_final_states(), __t));
}
// Creates the e-closure set for the initial state __i.
inline _StateSet _Grep_matcher::
_M_e_closure(_StateIdT __i)
{
_StateSet __s;
__s.insert(__i);
_StateStack __stack;
__stack.push(__i);
return this->_M_e_closure(__stack, __s);
}
// Creates the e-closure set for an arbitrary state set __s.
inline _StateSet _Grep_matcher::
_M_e_closure(const _StateSet& __s)
{
_StateStack __stack;
for (_StateSet::const_iterator __i = __s.begin(); __i != __s.end(); ++__i)
__stack.push(*__i);
return this->_M_e_closure(__stack, __s);
}
inline _StateSet _Grep_matcher::
_M_e_closure(_StateStack& __stack, const _StateSet& __s)
{
_StateSet __e = __s;
while (!__stack.empty())
{
_StateIdT __t = __stack.top(); __stack.pop();
if (__t == _S_invalid_state_id)
continue;
// for each __u with edge from __t to __u labeled e do ...
const _State& __state = _M_nfa->operator[](__t);
switch (__state._M_opcode)
{
case _S_opcode_alternative:
__add_visited_state(__state._M_next, __stack, __e);
__add_visited_state(__state._M_alt, __stack, __e);
break;
case _S_opcode_subexpr_begin:
__add_visited_state(__state._M_next, __stack, __e);
__state._M_tagger(_M_pattern, _M_results);
break;
case _S_opcode_subexpr_end:
__add_visited_state(__state._M_next, __stack, __e);
__state._M_tagger(_M_pattern, _M_results);
_M_results._M_set_matched(__state._M_subexpr, true);
break;
case _S_opcode_accept:
__add_visited_state(__state._M_next, __stack, __e);
break;
default:
break;
}
}
return __e;
}
_GLIBCXX_END_NAMESPACE_VERSION
} // namespace __detail
} // namespace