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regex.h: Executor caller.

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2013-08-22  Tim Shen  <timshen91@gmail.com>

	* include/bits/regex.h: Executor caller.
	* include/bits/regex_executor.h: Fix empty grouping problem.
	* include/bits/regex_executor.tcc: Same.
	* testsuite/28_regex/algorithms/regex_match/ecma/cstring_emptygroup.cc:
	  New.

From-SVN: r201914
This commit is contained in:
Tim Shen 2013-08-22 00:58:28 +00:00 committed by Tim Shen
parent 9ad30113d6
commit 1b488e33b6
5 changed files with 235 additions and 89 deletions
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8
libstdc++-v3/ChangeLog
View File

@ -1,3 +1,11 @@
2013-08-22 Tim Shen <timshen91@gmail.com>
* include/bits/regex.h: Executor caller.
* include/bits/regex_executor.h: Fix empty grouping problem.
* include/bits/regex_executor.tcc: Same.
* testsuite/28_regex/algorithms/regex_match/ecma/cstring_emptygroup.cc:
New.
2013-08-20 Phil Muldoon <pmuldoon@redhat.com>
PR libstdc++/53477

38
libstdc++-v3/include/bits/regex.h
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@ -2211,7 +2211,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
{
if (__re._M_automaton == nullptr)
return false;
if (__detail::__get_executor(__s, __e, __m, __re, __flags)->_M_match())
__detail::__get_executor(__s, __e, __m, __re, __flags)->_M_match();
if (__m.size() > 0 && __m[0].matched)
{
for (auto __it : __m)
if (!__it.matched)
@ -2371,22 +2372,25 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
if (__re._M_automaton == nullptr)
return false;
for (auto __cur = __first; __cur != __last; ++__cur) // Any KMP-like algo?
if (__detail::__get_executor(__cur, __last, __m, __re, __flags)
->_M_search_from_first())
{
for (auto __it : __m)
if (!__it.matched)
__it.first = __it.second = __last;
__m.at(__m.size()).first = __first;
__m.at(__m.size()).second = __m[0].first;
__m.at(__m.size()+1).first = __m[0].second;
__m.at(__m.size()+1).second = __last;
__m.at(__m.size()).matched =
(__m.prefix().first != __m.prefix().second);
__m.at(__m.size()+1).matched =
(__m.suffix().first != __m.suffix().second);
return true;
}
{
__detail::__get_executor(__cur, __last, __m, __re, __flags)
->_M_search_from_first();
if (__m.size() > 0 && __m[0].matched)
{
for (auto __it : __m)
if (!__it.matched)
__it.first = __it.second = __last;
__m.at(__m.size()).first = __first;
__m.at(__m.size()).second = __m[0].first;
__m.at(__m.size()+1).first = __m[0].second;
__m.at(__m.size()+1).second = __last;
__m.at(__m.size()).matched =
(__m.prefix().first != __m.prefix().second);
__m.at(__m.size()+1).matched =
(__m.suffix().first != __m.suffix().second);
return true;
}
}
return false;
}

94
libstdc++-v3/include/bits/regex_executor.h
View File

@ -28,12 +28,17 @@
* Do not attempt to use it directly. @headername{regex}
*/
// TODO: convert comments to doxygen format.
namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION
template<typename, typename>
class basic_regex;
template<typename>
class sub_match;
template<typename, typename>
class match_results;
_GLIBCXX_END_NAMESPACE_VERSION
@ -52,19 +57,20 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
class _Executor
{
public:
typedef match_results<_BiIter, _Alloc> _ResultsT;
typedef regex_constants::match_flag_type _FlagT;
typedef match_results<_BiIter, _Alloc> _ResultsT;
typedef std::vector<sub_match<_BiIter>, _Alloc> _ResultsVec;
typedef regex_constants::match_flag_type _FlagT;
virtual
~_Executor()
{ }
// Set matched when string exactly match the pattern.
virtual bool
virtual void
_M_match() = 0;
// Set matched when some prefix of the string matches the pattern.
virtual bool
virtual void
_M_search_from_first() = 0;
protected:
@ -74,20 +80,34 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
_ResultsT& __results,
_FlagT __flags,
_SizeT __size)
: _M_current(__begin), _M_end(__end),
_M_results(__results), _M_flags(__flags)
: _M_current(__begin), _M_end(__end), _M_results(__results),
_M_flags(__flags)
{
__results.resize(__size + 2);
for (auto __it : __results)
__it.matched = false;
__size += 2;
_M_results.resize(__size);
for (auto __i = 0; __i < __size; __i++)
_M_results[__i].matched = false;
}
_BiIter _M_current;
_BiIter _M_end;
_ResultsT& _M_results;
_FlagT _M_flags;
_BiIter _M_current;
_BiIter _M_end;
_ResultsVec& _M_results;
_FlagT _M_flags;
};
// A _DFSExecutor perform a DFS on given NFA and input string. At the very
// beginning the executor stands in the start state, then it try every
// possible state transition in current state recursively. Some state
// transitions consume input string, say, a single-char-matcher or a
// back-reference matcher; some not, like assertion or other anchor nodes.
// When the input is exhausted and the current state is an accepting state,
// the whole executor return true.
//
// TODO: This approach is exponentially slow for certain input.
// Try to compile the NFA to a DFA.
//
// Time complexity: exponential
// Space complexity: O(__end - __begin)
template<typename _BiIter, typename _Alloc,
typename _CharT, typename _TraitsT>
class _DFSExecutor
@ -97,6 +117,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
typedef _Executor<_BiIter, _Alloc, _CharT, _TraitsT> _BaseT;
typedef _NFA<_CharT, _TraitsT> _RegexT;
typedef typename _BaseT::_ResultsT _ResultsT;
typedef typename _BaseT::_ResultsVec _ResultsVec;
typedef regex_constants::match_flag_type _FlagT;
_DFSExecutor(_BiIter __begin,
@ -105,37 +126,39 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
const _RegexT& __nfa,
_FlagT __flags)
: _BaseT(__begin, __end, __results, __flags, __nfa._M_sub_count()),
_M_traits(_TraitsT()), _M_nfa(__nfa)
_M_traits(_TraitsT()), _M_nfa(__nfa), _M_results_ret(this->_M_results)
{ }
bool
void
_M_match()
{ return _M_dfs<true>(_M_nfa._M_start()); }
{ _M_dfs<true>(_M_nfa._M_start()); }
bool
void
_M_search_from_first()
{ return _M_dfs<false>(_M_nfa._M_start()); }
{ _M_dfs<false>(_M_nfa._M_start()); }
private:
template<bool __match_mode>
bool
_M_dfs(_StateIdT __i);
_ResultsVec _M_results_ret;
_TraitsT _M_traits;
const _RegexT& _M_nfa;
};
// It's essentially a variant of Single-Source-Shortest-Path problem, where,
// the matching results is the final distance and should be minimized.
// Instead of using Dijkstra Algorithm, I pick up the queue-optimizaed
// (BFS-like) Bellman-Ford algorithm,
// SPFA(http://en.wikipedia.org/wiki/Shortest_Path_Faster_Algorithm).
// Like the DFS approach, it try every possible state transition; Unlike DFS,
// it uses a queue instead of a stack to store matching states. It's a BFS
// approach.
//
// Russ Cox's article(http://swtch.com/~rsc/regexp/regexp1.html) explained
// this algorithm clearly.
//
// Every entry of _M_covered saves the solution(grouping status) for every
// matching head. When states transfer, solutions will be compared and
// matching head. When states transit, solutions will be compared and
// deduplicated(based on which greedy mode we have).
//
// Time complexity: O(_M_str_cur.size() * _M_nfa.size())
// Time complexity: O((__end - __begin) * _M_nfa.size())
// Space complexity: O(_M_nfa.size() * _M_nfa.mark_count())
template<typename _BiIter, typename _Alloc,
typename _CharT, typename _TraitsT>
@ -146,12 +169,13 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
typedef _Executor<_BiIter, _Alloc, _CharT, _TraitsT> _BaseT;
typedef _NFA<_CharT, _TraitsT> _RegexT;
typedef typename _BaseT::_ResultsT _ResultsT;
typedef std::unique_ptr<_ResultsT> _ResultsPtr;
typedef typename _BaseT::_ResultsVec _ResultsVec;
typedef std::unique_ptr<_ResultsVec> _ResultsPtr;
typedef regex_constants::match_flag_type _FlagT;
_BFSExecutor(_BiIter __begin,
_BiIter __end,
_ResultsT& __results,
_ResultsT& __results,
const _RegexT& __nfa,
_FlagT __flags)
: _BaseT(__begin, __end, __results, __flags, __nfa._M_sub_count()),
@ -159,21 +183,21 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
{
if (_M_nfa._M_start() != _S_invalid_state_id)
_M_covered[_M_nfa._M_start()] =
_ResultsPtr(new _ResultsT(this->_M_results));
_ResultsPtr(new _ResultsVec(this->_M_results));
_M_e_closure();
}
bool
void
_M_match()
{ return _M_main_loop<true>(); }
{ _M_main_loop<true>(); }
bool
void
_M_search_from_first()
{ return _M_main_loop<false>(); }
{ _M_main_loop<false>(); }
private:
template<bool __match_mode>
bool
void
_M_main_loop();
void
@ -183,13 +207,13 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
_M_move();
bool
_M_match_less_than(_StateIdT __u, _StateIdT __v) const;
_M_match_less_than(const _ResultsVec& __u, const _ResultsVec& __v) const;
bool
_M_includes_some() const;
std::map<_StateIdT, _ResultsPtr> _M_covered;
const _RegexT& _M_nfa;
const _RegexT& _M_nfa;
};
//@} regex-detail

126
libstdc++-v3/include/bits/regex_executor.tcc
View File

@ -34,19 +34,18 @@ namespace __detail
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION
// TODO: This is too slow. Try to compile the NFA to a DFA.
template<typename _BiIter, typename _Alloc,
typename _CharT, typename _TraitsT>
template<bool __match_mode>
bool _DFSExecutor<_BiIter, _Alloc, _CharT, _TraitsT>::
_M_dfs(_StateIdT __i)
{
auto& __current = this->_M_current;
auto& __end = this->_M_end;
auto& __results = this->_M_results;
if (__i == _S_invalid_state_id)
// This is not that certain. Need deeper investigate.
return false;
auto& __current = this->_M_current;
auto& __end = this->_M_end;
auto& __results = _M_results_ret;
const auto& __state = _M_nfa[__i];
bool __ret = false;
switch (__state._M_opcode)
@ -59,14 +58,33 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
|| _M_dfs<__match_mode>(__state._M_next);
break;
case _S_opcode_subexpr_begin:
__results.at(__state._M_subexpr).first = __current;
__ret = _M_dfs<__match_mode>(__state._M_next);
// Here's the critical part: if there's nothing changed since last
// visit, do NOT continue. This prevents the executor from get into
// infinite loop when use "()*" to match "".
//
// Every change on __results will be roll back after the recursion
// step finished.
if (!__results[__state._M_subexpr].matched
|| __results[__state._M_subexpr].first != __current)
{
auto __back = __current;
__results[__state._M_subexpr].first = __current;
__ret = _M_dfs<__match_mode>(__state._M_next);
__results[__state._M_subexpr].first = __back;
}
break;
case _S_opcode_subexpr_end:
__results.at(__state._M_subexpr).second = __current;
__results.at(__state._M_subexpr).matched = true;
__ret = _M_dfs<__match_mode>(__state._M_next);
__results.at(__state._M_subexpr).matched = __ret;
if (__results[__state._M_subexpr].second != __current
|| __results[__state._M_subexpr].matched != true)
{
auto __back = __results[__state._M_subexpr];
__results[__state._M_subexpr].second = __current;
__results[__state._M_subexpr].matched = true;
__ret = _M_dfs<__match_mode>(__state._M_next);
__results[__state._M_subexpr] = __back;
}
else
__ret = _M_dfs<__match_mode>(__state._M_next);
break;
case _S_opcode_match:
if (__current != __end && __state._M_matches(*__current))
@ -82,7 +100,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
// If matched, keep going; else just return to try another state.
case _S_opcode_backref:
{
auto& __submatch = __results.at(__state._M_backref_index);
auto& __submatch = __results[__state._M_backref_index];
if (!__submatch.matched)
break;
auto __last = __current;
@ -92,12 +110,15 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
++__last;
if (_M_traits.transform(__submatch.first, __submatch.second)
== _M_traits.transform(__current, __last))
{
auto __backup = __current;
__current = __last;
if (__last != __current)
{
auto __backup = __current;
__current = __last;
__ret = _M_dfs<__match_mode>(__state._M_next);
__current = __backup;
}
else
__ret = _M_dfs<__match_mode>(__state._M_next);
__current = __backup;
}
}
break;
case _S_opcode_accept:
@ -105,6 +126,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
__ret = __current == __end;
else
__ret = true;
if (__ret)
this->_M_results = __results;
break;
default:
_GLIBCXX_DEBUG_ASSERT(false);
@ -115,22 +138,21 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
template<typename _BiIter, typename _Alloc,
typename _CharT, typename _TraitsT>
template<bool __match_mode>
bool _BFSExecutor<_BiIter, _Alloc, _CharT, _TraitsT>::
void _BFSExecutor<_BiIter, _Alloc, _CharT, _TraitsT>::
_M_main_loop()
{
while (this->_M_current != this->_M_end)
{
if (!__match_mode)
if (_M_includes_some())
return true;
return;
_M_move();
++this->_M_current;
_M_e_closure();
}
return _M_includes_some();
_M_includes_some();
}
// The SPFA approach.
template<typename _BiIter, typename _Alloc,
typename _CharT, typename _TraitsT>
void _BFSExecutor<_BiIter, _Alloc, _CharT, _TraitsT>::
@ -152,13 +174,17 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
const auto& __state = _M_nfa[__u];
// Can be implemented using method, but there're too much arguments.
// I would use macro function before C++11, but lambda is a better
// choice, since hopefully compiler can inline it.
auto __add_visited_state = [&](_StateIdT __v)
{
if (__v == _S_invalid_state_id)
return;
if (_M_match_less_than(__u, __v))
if (_M_covered.count(__u) != 0
&& (_M_covered.count(__v) == 0
|| _M_match_less_than(*_M_covered[__u], *_M_covered[__v])))
{
_M_covered[__v] = _ResultsPtr(new _ResultsT(*_M_covered[__u]));
_M_covered[__v] = _ResultsPtr(new _ResultsVec(*_M_covered[__u]));
// if a state is updated, it's outgoing neighbors should be
// reconsidered too. Push them to the queue.
if (!__in_q[__v])
@ -176,13 +202,23 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
__add_visited_state(__state._M_alt);
break;
case _S_opcode_subexpr_begin:
_M_covered[__u]->at(__state._M_subexpr).first = __current;
__add_visited_state(__state._M_next);
{
auto& __cu = *_M_covered[__u];
auto __back = __cu[__state._M_subexpr].first;
__cu[__state._M_subexpr].first = __current;
__add_visited_state(__state._M_next);
__cu[__state._M_subexpr].first = __back;
}
break;
case _S_opcode_subexpr_end:
_M_covered[__u]->at(__state._M_subexpr).second = __current;
_M_covered[__u]->at(__state._M_subexpr).matched = true;
__add_visited_state(__state._M_next);
{
auto& __cu = *_M_covered[__u];
auto __back = __cu[__state._M_subexpr];
__cu[__state._M_subexpr].second = __current;
__cu[__state._M_subexpr].matched = true;
__add_visited_state(__state._M_next);
__cu[__state._M_subexpr] = __back;
}
break;
case _S_opcode_match:
break;
@ -206,9 +242,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
const auto& __state = _M_nfa[__it.first];
if (__state._M_opcode == _S_opcode_match
&& __state._M_matches(*this->_M_current))
if (_M_match_less_than(__it.first, __state._M_next)
&& __state._M_next != _S_invalid_state_id)
__next[__state._M_next] = move(__it.second);
if (__state._M_next != _S_invalid_state_id)
if (__next.count(__state._M_next) == 0
|| _M_match_less_than(*__it.second, *__next[__state._M_next]))
__next[__state._M_next] = move(__it.second);
}
_M_covered = move(__next);
}
@ -216,14 +253,28 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
template<typename _BiIter, typename _Alloc,
typename _CharT, typename _TraitsT>
bool _BFSExecutor<_BiIter, _Alloc, _CharT, _TraitsT>::
_M_match_less_than(_StateIdT __u, _StateIdT __v) const
_M_match_less_than(const _ResultsVec& __u, const _ResultsVec& __v) const
{
if (_M_covered.count(__u) == 0)
return false;
if (_M_covered.count(__v) > 0)
return true;
// TODO: Greedy and Non-greedy support
return true;
_GLIBCXX_DEBUG_ASSERT(__u.size() == __v.size());
auto __size = __u.size();
for (auto __i = 0; __i < __size; __i++)
{
auto& __uit = __u[__i], __vit = __v[__i];
if (__uit.matched && !__vit.matched)
return true;
if (!__uit.matched && __vit.matched)
return false;
if (__uit.matched && __vit.matched)
{
// GREEDY
if (__uit.first != __vit.first)
return __uit.first < __vit.first;
if (__uit.second != __vit.second)
return __uit.second > __vit.second;
}
}
return false;
}
template<typename _BiIter, typename _Alloc,
@ -265,11 +316,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
typedef std::unique_ptr<_Executor<_BiIter, _Alloc, _CharT, _TraitsT>>
_ExecutorPtr;
typedef _DFSExecutor<_BiIter, _Alloc, _CharT, _TraitsT> _DFSExecutorT;
typedef _BFSExecutor<_BiIter, _Alloc, _CharT, _TraitsT> _BFSExecutorT;
auto __p = std::static_pointer_cast<_NFA<_CharT, _TraitsT>>
(__re._M_automaton);
if (__p->_M_has_backref)
return _ExecutorPtr(new _DFSExecutorT(__b, __e, __m, *__p, __flags));
return _ExecutorPtr(new _DFSExecutorT(__b, __e, __m, *__p, __flags));
return _ExecutorPtr(new _BFSExecutorT(__b, __e, __m, *__p, __flags));
}
_GLIBCXX_END_NAMESPACE_VERSION

58
libstdc++-v3/testsuite/28_regex/algorithms/regex_match/ecma/cstring_emptygroup.cc Normal file
View File

@ -0,0 +1,58 @@
// { dg-options "-std=gnu++11" }
//
// 2013-08-22 Tim Shen <timshen91@gmail.com>
//
// Copyright (C) 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.
//
// You should have received a copy of the GNU General Public License along
// with this library; see the file COPYING3. If not see
// <http://www.gnu.org/licenses/>.
// 28.11.2 regex_match
// Tests ECMAScript empty-grouping against a C-string.
#include <regex>
#include <testsuite_hooks.h>
using namespace std;
void
test01()
{
bool test __attribute__((unused)) = true;
{
regex re("()*\\1");
cmatch m;
const char s[] = "";
VERIFY( regex_match(s, m, re) );
VERIFY( m.size() == 2 );
VERIFY( m[0].matched );
VERIFY( m[1].matched );
}
{
regex re("()*");
cmatch m;
const char s[] = "";
VERIFY( regex_match(s, m, re) );
}
}
int
main()
{
test01();
return 0;
}