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regex.h: Remove virtual class _Automaton. 

2013-10-20  Tim Shen  <timshen91@gmail.com>

	* include/bits/regex.h: Remove virtual class _Automaton.
	* include/bits/regex_automaton.h: Likewise.
	* include/bits/regex.tcc: Adjust comment for policy changing.
	* include/bits/regex_executor.h: Update comments of complexity.
	* include/bits/regex_executor.tcc: Adjust executor choosing
	policy. Now DFS executor is the default one.
	* testsuite/util/testsuite_regex.h (regex_match_debug,
	regex_search_debug): Adjust for policy changing.

From-SVN: r203875
This commit is contained in:
Tim Shen 2013-10-20 10:07:29 +00:00 committed by Tim Shen
parent f5b9d5e877
commit 603b781be4
7 changed files with 66 additions and 57 deletions
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11
libstdc++-v3/ChangeLog
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@ -1,3 +1,14 @@
2013-10-20 Tim Shen <timshen91@gmail.com>
* include/bits/regex.h: Remove virtual class _Automaton.
* include/bits/regex_automaton.h: Likewise.
* include/bits/regex.tcc: Adjust comment for policy changing.
* include/bits/regex_executor.h: Update comments of complexity.
* include/bits/regex_executor.tcc: Adjust executor choosing
policy. Now DFS executor is the default one.
* testsuite/util/testsuite_regex.h (regex_match_debug,
regex_search_debug): Adjust for policy changing.
2013-10-20 Chris Jefferson <chris@bubblescope.net>
Paolo Carlini <paolo.carlini@oracle.com>

2
libstdc++-v3/include/bits/regex.h
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@ -727,7 +727,7 @@ _GLIBCXX_END_NAMESPACE_VERSION
#endif
protected:
typedef std::shared_ptr<__detail::_Automaton<_Ch_type, _Rx_traits>>
typedef std::shared_ptr<__detail::_NFA<_Ch_type, _Rx_traits>>
_AutomatonPtr;
template<typename _BiIter, typename _Alloc,

4
libstdc++-v3/include/bits/regex.tcc
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@ -38,8 +38,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
// Result of merging regex_match and regex_search.
//
// __policy now can be _S_auto(auto dispatch by checking back-references)
// and _S_force_dfs(just use _DFSExecutor).
// __policy now can be _S_auto (auto dispatch) and _S_alternate (use
// the other one if possible, for test purpose).
//
// That __match_mode is true means regex_match, else regex_search.
template<typename _BiIter, typename _Alloc,

24
libstdc++-v3/include/bits/regex_automaton.h
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@ -104,31 +104,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
#endif
};
/// Base class for, um, automata. Could be an NFA or a DFA. Your choice.
template<typename _CharT, typename _TraitsT>
class _Automaton
{
public:
typedef size_t _SizeT;
public:
virtual
~_Automaton()
{ }
virtual _SizeT
_M_sub_count() const = 0;
#ifdef _GLIBCXX_DEBUG
virtual std::ostream&
_M_dot(std::ostream& __ostr) const = 0;
#endif
};
template<typename _CharT, typename _TraitsT>
class _NFA
: public _Automaton<_CharT, _TraitsT>,
public std::vector<_State<_CharT, _TraitsT>>
: public std::vector<_State<_CharT, _TraitsT>>
{
public:
typedef _State<_CharT, _TraitsT> _StateT;

36
libstdc++-v3/include/bits/regex_executor.h
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@ -179,8 +179,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
// 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)
// Time complexity: o(match_length), O(2^(_M_nfa->size()))
// Space complexity: \theta(match_results.size() + match_length)
template<typename _BiIter, typename _Alloc,
typename _CharT, typename _TraitsT>
class _DFSExecutor
@ -200,16 +200,14 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
const _RegexT& __re,
_FlagT __flags)
: _BaseT(__begin, __end, __results, __re, __flags),
_M_nfa(*std::static_pointer_cast<_NFA<_CharT, _TraitsT>>
(__re._M_automaton)),
_M_start_state(_M_nfa._M_start())
_M_nfa(__re._M_automaton), _M_start_state(_M_nfa->_M_start())
{ }
private:
void
_M_init(_BiIter __cur)
{
_M_cur_results.resize(_M_nfa._M_sub_count() + 2);
_M_cur_results.resize(_M_nfa->_M_sub_count() + 2);
this->_M_current = __cur;
}
@ -235,9 +233,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
}
// To record current solution.
_ResultsVec _M_cur_results;
const _NFAT& _M_nfa;
_StateIdT _M_start_state;
std::shared_ptr<_NFAT> _M_nfa;
_ResultsVec _M_cur_results;
_StateIdT _M_start_state;
};
// Like the DFS approach, it try every possible state transition; Unlike DFS,
@ -251,8 +249,13 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
// matching head. When states transit, solutions will be compared and
// deduplicated(based on which greedy mode we have).
//
// Time complexity: O((__end - __begin) * _M_nfa.size())
// Space complexity: O(_M_nfa.size() * _M_nfa.mark_count())
// Time complexity: o(match_length * (quantifier_number
// + match_results.size())
// O(match_length * _M_nfa->size()
// * (quantifier_number + match_results.size())
// Space complexity: o(quantifier_number + match_results.size())
// O(_M_nfa->size()
// * (quantifier_number + match_results.size())
template<typename _BiIter, typename _Alloc,
typename _CharT, typename _TraitsT>
class _BFSExecutor
@ -382,11 +385,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
const _RegexT& __re,
_FlagT __flags)
: _BaseT(__begin, __end, __results, __re, __flags),
_M_nfa(*std::static_pointer_cast<_NFA<_CharT, _TraitsT>>
(__re._M_automaton)),
_M_match_stack(_M_nfa.size()),
_M_stack(_M_nfa.size()),
_M_start_state(_M_nfa._M_start())
_M_nfa(__re._M_automaton), _M_match_stack(_M_nfa->size()),
_M_stack(_M_nfa->size()), _M_start_state(_M_nfa->_M_start())
{ }
private:
@ -398,7 +398,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
_ResultsVec& __res(this->_M_results);
_M_covered[this->_M_start_state] =
_ResultsPtr(new _ResultsEntry(__res.size(),
_M_nfa._M_quant_count));
_M_nfa->_M_quant_count));
_M_stack._M_push(this->_M_start_state);
}
@ -428,7 +428,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
this->_M_flags));
}
const _NFAT& _M_nfa;
std::shared_ptr<_NFAT> _M_nfa;
std::map<_StateIdT, _ResultsPtr> _M_covered;
_TodoList _M_match_stack;
_TodoList _M_stack;

42
libstdc++-v3/include/bits/regex_executor.tcc
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@ -28,6 +28,13 @@
* Do not attempt to use it directly. @headername{regex}
*/
// See below __get_executor to get what this is talking about. The default
// value 1 indicated a conservative optimization without giving up worst case
// performance.
#ifndef _GLIBCXX_REGEX_DFS_QUANTIFIERS_LIMIT
#define _GLIBCXX_REGEX_DFS_QUANTIFIERS_LIMIT 1
#endif
namespace std _GLIBCXX_VISIBILITY(default)
{
namespace __detail
@ -60,7 +67,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
_M_dfs(_StateIdT __i)
{
auto& __current = this->_M_current;
const auto& __state = _M_nfa[__i];
const auto& __state = (*_M_nfa)[__i];
bool __ret = false;
switch (__state._M_opcode)
{
@ -216,7 +223,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
{
auto __u = _M_stack._M_pop();
_GLIBCXX_DEBUG_ASSERT(_M_covered.count(__u));
const auto& __state = _M_nfa[__u];
const auto& __state = (*_M_nfa)[__u];
// Can be implemented using method, but there will be too many
// arguments. I would use macro function before C++11, but lambda is
@ -314,7 +321,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
while (!_M_match_stack._M_empty())
{
auto __u = _M_match_stack._M_pop();
const auto& __state = _M_nfa[__u];
const auto& __state = (*_M_nfa)[__u];
auto& __cu = _M_covered[__u];
if (__state._M_matches(*this->_M_current)
&& (__next.count(__state._M_next) == 0
@ -333,7 +340,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
_M_includes_some()
{
bool __succ = false;
for (auto __u : _M_nfa._M_final_states())
for (auto __u : _M_nfa->_M_final_states())
if (_M_covered.count(__u))
{
__succ = true;
@ -380,8 +387,21 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
}
enum class _RegexExecutorPolicy : int
{ _S_auto, _S_force_dfs };
{ _S_auto, _S_alternate };
// This function decide which executor to use under given circumstances.
// The _S_auto policy now is the following: if a NFA has no back-references
// and has more than _GLIBCXX_REGEX_DFS_QUANTIFIERS_LIMIT quantifiers
// (*, +, ?), the _BFSExecutor will be used, other wise _DFSExecutor. This is
// because _DFSExecutor has a exponential upper bound, but better best-case
// performace. Meanwhile, _BFSExecutor can effectively prevent from
// exponential-long time matching (which must contains many quantifiers), but
// it's slower in average.
//
// For simple regex, _BFSExecutor could be 2 or more times slower than
// _DFSExecutor.
//
// Of course, _BFSExecutor cannot handle back-references.
template<typename _BiIter, typename _Alloc,
typename _CharT, typename _TraitsT,
_RegexExecutorPolicy __policy>
@ -396,12 +416,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
_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 (__policy == _RegexExecutorPolicy::_S_force_dfs
|| (__policy == _RegexExecutorPolicy::_S_auto && __p->_M_has_backref))
return _ExecutorPtr(new _DFSExecutorT(__b, __e, __m, __re, __flags));
return _ExecutorPtr(new _BFSExecutorT(__b, __e, __m, __re, __flags));
if (!__re._M_automaton->_M_has_backref
&& (__policy == _RegexExecutorPolicy::_S_alternate
|| __re._M_automaton->_M_quant_count
> _GLIBCXX_REGEX_DFS_QUANTIFIERS_LIMIT))
return _ExecutorPtr(new _BFSExecutorT(__b, __e, __m, __re, __flags));
return _ExecutorPtr(new _DFSExecutorT(__b, __e, __m, __re, __flags));
}
_GLIBCXX_END_NAMESPACE_VERSION

4
libstdc++-v3/testsuite/util/testsuite_regex.h
View File

@ -148,7 +148,7 @@ namespace __gnu_test
(__s, __e, __m, __re, __flags);
match_results<_Bi_iter, _Alloc> __mm;
auto __res2 = __regex_algo_impl<_Bi_iter, _Alloc, _Ch_type, _Rx_traits,
_RegexExecutorPolicy::_S_force_dfs, true>
_RegexExecutorPolicy::_S_alternate, true>
(__s, __e, __mm, __re, __flags);
if (__res1 == __res2 && __m == __mm)
return __res1;
@ -234,7 +234,7 @@ namespace __gnu_test
(__s, __e, __m, __re, __flags);
match_results<_Bi_iter, _Alloc> __mm;
auto __res2 = __regex_algo_impl<_Bi_iter, _Alloc, _Ch_type, _Rx_traits,
_RegexExecutorPolicy::_S_force_dfs, false>
_RegexExecutorPolicy::_S_alternate, false>
(__s, __e, __mm, __re, __flags);
if (__res1 == __res2 && __m == __mm)
return __res1;