xref: /netbsd-src/external/gpl3/gcc/dist/libstdc++-v3/include/bits/regex_executor.tcc (revision 0a3071956a3a9fdebdbf7f338cf2d439b45fc728)
1 // class template regex -*- C++ -*-
2 
3 // Copyright (C) 2013-2022 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_executor.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 _GLIBCXX_BEGIN_NAMESPACE_VERSION
34 
35 namespace __detail
36 {
37   template<typename _BiIter, typename _Alloc, typename _TraitsT,
38 	   bool __dfs_mode>
39     bool _Executor<_BiIter, _Alloc, _TraitsT, __dfs_mode>::
_M_search()40     _M_search()
41     {
42       if (_M_search_from_first())
43 	return true;
44       if (_M_flags & regex_constants::match_continuous)
45 	return false;
46       _M_flags |= regex_constants::match_prev_avail;
47       while (_M_begin != _M_end)
48 	{
49 	  ++_M_begin;
50 	  if (_M_search_from_first())
51 	    return true;
52 	}
53       return false;
54     }
55 
56   // The _M_main function operates in different modes, DFS mode or BFS mode,
57   // indicated by template parameter __dfs_mode, and dispatches to one of the
58   // _M_main_dispatch overloads.
59   //
60   // ------------------------------------------------------------
61   //
62   // DFS mode:
63   //
64   // It applies a Depth-First-Search (aka backtracking) on given NFA and input
65   // string.
66   // At the very beginning the executor stands in the start state, then it
67   // tries every possible state transition in current state recursively. Some
68   // state transitions consume input string, say, a single-char-matcher or a
69   // back-reference matcher; some don't, like assertion or other anchor nodes.
70   // When the input is exhausted and/or the current state is an accepting
71   // state, the whole executor returns true.
72   //
73   // TODO: This approach is exponentially slow for certain input.
74   //       Try to compile the NFA to a DFA.
75   //
76   // Time complexity: \Omega(match_length), O(2^(_M_nfa.size()))
77   // Space complexity: \theta(match_results.size() + match_length)
78   //
79   template<typename _BiIter, typename _Alloc, typename _TraitsT,
80 	   bool __dfs_mode>
81     bool _Executor<_BiIter, _Alloc, _TraitsT, __dfs_mode>::
_M_main_dispatch(_Match_mode __match_mode,__dfs)82     _M_main_dispatch(_Match_mode __match_mode, __dfs)
83     {
84       _M_has_sol = false;
85       *_M_states._M_get_sol_pos() = _BiIter();
86       _M_cur_results = _M_results;
87       _M_dfs(__match_mode, _M_states._M_start);
88       return _M_has_sol;
89     }
90 
91   // ------------------------------------------------------------
92   //
93   // BFS mode:
94   //
95   // Russ Cox's article (http://swtch.com/~rsc/regexp/regexp1.html)
96   // explained this algorithm clearly.
97   //
98   // It first computes epsilon closure (states that can be achieved without
99   // consuming characters) for every state that's still matching,
100   // using the same DFS algorithm, but doesn't re-enter states (using
101   // _M_states._M_visited to check), nor follow _S_opcode_match.
102   //
103   // Then apply DFS using every _S_opcode_match (in _M_states._M_match_queue)
104   // as the start state.
105   //
106   // It significantly reduces potential duplicate states, so has a better
107   // upper bound; but it requires more overhead.
108   //
109   // Time complexity: \Omega(match_length * match_results.size())
110   //                  O(match_length * _M_nfa.size() * match_results.size())
111   // Space complexity: \Omega(_M_nfa.size() + match_results.size())
112   //                   O(_M_nfa.size() * match_results.size())
113   template<typename _BiIter, typename _Alloc, typename _TraitsT,
114 	   bool __dfs_mode>
115     bool _Executor<_BiIter, _Alloc, _TraitsT, __dfs_mode>::
_M_main_dispatch(_Match_mode __match_mode,__bfs)116     _M_main_dispatch(_Match_mode __match_mode, __bfs)
117     {
118       _M_states._M_queue(_M_states._M_start, _M_results);
119       bool __ret = false;
120       while (1)
121 	{
122 	  _M_has_sol = false;
123 	  if (_M_states._M_match_queue.empty())
124 	    break;
125 	  std::fill_n(_M_states._M_visited_states, _M_nfa.size(), false);
126 	  auto __old_queue = std::move(_M_states._M_match_queue);
127 	  auto __alloc = _M_cur_results.get_allocator();
128 	  for (auto& __task : __old_queue)
129 	    {
130 	      _M_cur_results = _ResultsVec(std::move(__task.second), __alloc);
131 	      _M_dfs(__match_mode, __task.first);
132 	    }
133 	  if (__match_mode == _Match_mode::_Prefix)
134 	    __ret |= _M_has_sol;
135 	  if (_M_current == _M_end)
136 	    break;
137 	  ++_M_current;
138 	}
139       if (__match_mode == _Match_mode::_Exact)
140 	__ret = _M_has_sol;
141       _M_states._M_match_queue.clear();
142       return __ret;
143     }
144 
145   // Return whether now match the given sub-NFA.
146   template<typename _BiIter, typename _Alloc, typename _TraitsT,
147 	   bool __dfs_mode>
148     bool _Executor<_BiIter, _Alloc, _TraitsT, __dfs_mode>::
_M_lookahead(_StateIdT __next)149     _M_lookahead(_StateIdT __next)
150     {
151       // Backreferences may refer to captured content.
152       // We may want to make this faster by not copying,
153       // but let's not be clever prematurely.
154       _ResultsVec __what(_M_cur_results);
155       _Executor __sub(_M_current, _M_end, __what, _M_re, _M_flags);
156       __sub._M_states._M_start = __next;
157       if (__sub._M_search_from_first())
158 	{
159 	  for (size_t __i = 0; __i < __what.size(); __i++)
160 	    if (__what[__i].matched)
161 	      _M_cur_results[__i] = __what[__i];
162 	  return true;
163 	}
164       return false;
165     }
166 
167   // __rep_count records how many times (__rep_count.second)
168   // this node is visited under certain input iterator
169   // (__rep_count.first). This prevent the executor from entering
170   // infinite loop by refusing to continue when it's already been
171   // visited more than twice. It's `twice` instead of `once` because
172   // we need to spare one more time for potential group capture.
173   template<typename _BiIter, typename _Alloc, typename _TraitsT,
174 	   bool __dfs_mode>
175     void _Executor<_BiIter, _Alloc, _TraitsT, __dfs_mode>::
_M_rep_once_more(_Match_mode __match_mode,_StateIdT __i)176     _M_rep_once_more(_Match_mode __match_mode, _StateIdT __i)
177     {
178       const auto& __state = _M_nfa[__i];
179       auto& __rep_count = _M_rep_count[__i];
180       if (__rep_count.second == 0 || __rep_count.first != _M_current)
181 	{
182 	  auto __back = __rep_count;
183 	  __rep_count.first = _M_current;
184 	  __rep_count.second = 1;
185 	  _M_dfs(__match_mode, __state._M_alt);
186 	  __rep_count = __back;
187 	}
188       else
189 	{
190 	  if (__rep_count.second < 2)
191 	    {
192 	      __rep_count.second++;
193 	      _M_dfs(__match_mode, __state._M_alt);
194 	      __rep_count.second--;
195 	    }
196 	}
197     }
198 
199   // _M_alt branch is "match once more", while _M_next is "get me out
200   // of this quantifier". Executing _M_next first or _M_alt first don't
201   // mean the same thing, and we need to choose the correct order under
202   // given greedy mode.
203   template<typename _BiIter, typename _Alloc, typename _TraitsT,
204 	   bool __dfs_mode>
205     void _Executor<_BiIter, _Alloc, _TraitsT, __dfs_mode>::
_M_handle_repeat(_Match_mode __match_mode,_StateIdT __i)206     _M_handle_repeat(_Match_mode __match_mode, _StateIdT __i)
207     {
208       const auto& __state = _M_nfa[__i];
209 
210       // Greedy.
211       if (!__state._M_neg)
212 	{
213 	  _M_rep_once_more(__match_mode, __i);
214 	  // If it's DFS executor and already accepted, we're done.
215 	  if (!__dfs_mode || !_M_has_sol)
216 	    _M_dfs(__match_mode, __state._M_next);
217 	}
218       else // Non-greedy mode
219 	{
220 	  if (__dfs_mode)
221 	    {
222 	      // vice-versa.
223 	      _M_dfs(__match_mode, __state._M_next);
224 	      if (!_M_has_sol)
225 		_M_rep_once_more(__match_mode, __i);
226 	    }
227 	  else
228 	    {
229 	      // DON'T attempt anything, because there's already another
230 	      // state with higher priority accepted. This state cannot
231 	      // be better by attempting its next node.
232 	      if (!_M_has_sol)
233 		{
234 		  _M_dfs(__match_mode, __state._M_next);
235 		  // DON'T attempt anything if it's already accepted. An
236 		  // accepted state *must* be better than a solution that
237 		  // matches a non-greedy quantifier one more time.
238 		  if (!_M_has_sol)
239 		    _M_rep_once_more(__match_mode, __i);
240 		}
241 	    }
242 	}
243     }
244 
245   template<typename _BiIter, typename _Alloc, typename _TraitsT,
246 	   bool __dfs_mode>
247     void _Executor<_BiIter, _Alloc, _TraitsT, __dfs_mode>::
_M_handle_subexpr_begin(_Match_mode __match_mode,_StateIdT __i)248     _M_handle_subexpr_begin(_Match_mode __match_mode, _StateIdT __i)
249     {
250       const auto& __state = _M_nfa[__i];
251 
252       auto& __res = _M_cur_results[__state._M_subexpr];
253       auto __back = __res.first;
254       __res.first = _M_current;
255       _M_dfs(__match_mode, __state._M_next);
256       __res.first = __back;
257     }
258 
259   template<typename _BiIter, typename _Alloc, typename _TraitsT,
260 	   bool __dfs_mode>
261     void _Executor<_BiIter, _Alloc, _TraitsT, __dfs_mode>::
_M_handle_subexpr_end(_Match_mode __match_mode,_StateIdT __i)262     _M_handle_subexpr_end(_Match_mode __match_mode, _StateIdT __i)
263     {
264       const auto& __state = _M_nfa[__i];
265 
266       auto& __res = _M_cur_results[__state._M_subexpr];
267       auto __back = __res;
268       __res.second = _M_current;
269       __res.matched = true;
270       _M_dfs(__match_mode, __state._M_next);
271       __res = __back;
272     }
273 
274   template<typename _BiIter, typename _Alloc, typename _TraitsT,
275 	   bool __dfs_mode>
276     inline void _Executor<_BiIter, _Alloc, _TraitsT, __dfs_mode>::
_M_handle_line_begin_assertion(_Match_mode __match_mode,_StateIdT __i)277     _M_handle_line_begin_assertion(_Match_mode __match_mode, _StateIdT __i)
278     {
279       const auto& __state = _M_nfa[__i];
280       if (_M_at_begin())
281 	_M_dfs(__match_mode, __state._M_next);
282     }
283 
284   template<typename _BiIter, typename _Alloc, typename _TraitsT,
285 	   bool __dfs_mode>
286     inline void _Executor<_BiIter, _Alloc, _TraitsT, __dfs_mode>::
_M_handle_line_end_assertion(_Match_mode __match_mode,_StateIdT __i)287     _M_handle_line_end_assertion(_Match_mode __match_mode, _StateIdT __i)
288     {
289       const auto& __state = _M_nfa[__i];
290       if (_M_at_end())
291 	_M_dfs(__match_mode, __state._M_next);
292     }
293 
294   template<typename _BiIter, typename _Alloc, typename _TraitsT,
295 	   bool __dfs_mode>
296     inline void _Executor<_BiIter, _Alloc, _TraitsT, __dfs_mode>::
_M_handle_word_boundary(_Match_mode __match_mode,_StateIdT __i)297     _M_handle_word_boundary(_Match_mode __match_mode, _StateIdT __i)
298     {
299       const auto& __state = _M_nfa[__i];
300       if (_M_word_boundary() == !__state._M_neg)
301 	_M_dfs(__match_mode, __state._M_next);
302     }
303 
304   // Here __state._M_alt offers a single start node for a sub-NFA.
305   // We recursively invoke our algorithm to match the sub-NFA.
306   template<typename _BiIter, typename _Alloc, typename _TraitsT,
307 	   bool __dfs_mode>
308     void _Executor<_BiIter, _Alloc, _TraitsT, __dfs_mode>::
_M_handle_subexpr_lookahead(_Match_mode __match_mode,_StateIdT __i)309     _M_handle_subexpr_lookahead(_Match_mode __match_mode, _StateIdT __i)
310     {
311       const auto& __state = _M_nfa[__i];
312       if (_M_lookahead(__state._M_alt) == !__state._M_neg)
313 	_M_dfs(__match_mode, __state._M_next);
314     }
315 
316   template<typename _BiIter, typename _Alloc, typename _TraitsT,
317 	   bool __dfs_mode>
318     void _Executor<_BiIter, _Alloc, _TraitsT, __dfs_mode>::
_M_handle_match(_Match_mode __match_mode,_StateIdT __i)319     _M_handle_match(_Match_mode __match_mode, _StateIdT __i)
320     {
321       const auto& __state = _M_nfa[__i];
322 
323       if (_M_current == _M_end)
324 	return;
325       if (__dfs_mode)
326 	{
327 	  if (__state._M_matches(*_M_current))
328 	    {
329 	      ++_M_current;
330 	      _M_dfs(__match_mode, __state._M_next);
331 	      --_M_current;
332 	    }
333 	}
334       else
335 	if (__state._M_matches(*_M_current))
336 	  _M_states._M_queue(__state._M_next, _M_cur_results);
337     }
338 
339   template<typename _BiIter, typename _TraitsT>
340     struct _Backref_matcher
341     {
_Backref_matcherstd::__detail::_Backref_matcher342       _Backref_matcher(bool __icase, const _TraitsT& __traits)
343       : _M_traits(__traits) { }
344 
345       bool
_M_applystd::__detail::_Backref_matcher346       _M_apply(_BiIter __expected_begin,
347 	       _BiIter __expected_end, _BiIter __actual_begin,
348 	       _BiIter __actual_end)
349       {
350 	return _M_traits.transform(__expected_begin, __expected_end)
351 	    == _M_traits.transform(__actual_begin, __actual_end);
352       }
353 
354       const _TraitsT& _M_traits;
355     };
356 
357   template<typename _BiIter, typename _CharT>
358     struct _Backref_matcher<_BiIter, std::regex_traits<_CharT>>
359     {
360       using _TraitsT = std::regex_traits<_CharT>;
_Backref_matcherstd::__detail::_Backref_matcher361       _Backref_matcher(bool __icase, const _TraitsT& __traits)
362       : _M_icase(__icase), _M_traits(__traits) { }
363 
364       bool
_M_applystd::__detail::_Backref_matcher365       _M_apply(_BiIter __expected_begin,
366 	       _BiIter __expected_end, _BiIter __actual_begin,
367 	       _BiIter __actual_end)
368       {
369 	if (!_M_icase)
370 	  return _GLIBCXX_STD_A::__equal4(__expected_begin, __expected_end,
371 			       __actual_begin, __actual_end);
372 	typedef std::ctype<_CharT> __ctype_type;
373 	const auto& __fctyp = use_facet<__ctype_type>(_M_traits.getloc());
374 	return _GLIBCXX_STD_A::__equal4(__expected_begin, __expected_end,
375 			     __actual_begin, __actual_end,
376 			     [this, &__fctyp](_CharT __lhs, _CharT __rhs)
377 			     {
378 			       return __fctyp.tolower(__lhs)
379 				 == __fctyp.tolower(__rhs);
380 			     });
381       }
382 
383       bool _M_icase;
384       const _TraitsT& _M_traits;
385     };
386 
387   // First fetch the matched result from _M_cur_results as __submatch;
388   // then compare it with
389   // (_M_current, _M_current + (__submatch.second - __submatch.first)).
390   // If matched, keep going; else just return and try another state.
391   template<typename _BiIter, typename _Alloc, typename _TraitsT,
392 	   bool __dfs_mode>
393     void _Executor<_BiIter, _Alloc, _TraitsT, __dfs_mode>::
_M_handle_backref(_Match_mode __match_mode,_StateIdT __i)394     _M_handle_backref(_Match_mode __match_mode, _StateIdT __i)
395     {
396       __glibcxx_assert(__dfs_mode);
397 
398       const auto& __state = _M_nfa[__i];
399       auto& __submatch = _M_cur_results[__state._M_backref_index];
400       if (!__submatch.matched)
401 	return;
402       auto __last = _M_current;
403       for (auto __tmp = __submatch.first;
404 	   __last != _M_end && __tmp != __submatch.second;
405 	   ++__tmp)
406 	++__last;
407       if (_Backref_matcher<_BiIter, _TraitsT>(
408 	      _M_re.flags() & regex_constants::icase,
409 	      _M_re._M_automaton->_M_traits)._M_apply(
410 		  __submatch.first, __submatch.second, _M_current, __last))
411 	{
412 	  if (__last != _M_current)
413 	    {
414 	      auto __backup = _M_current;
415 	      _M_current = __last;
416 	      _M_dfs(__match_mode, __state._M_next);
417 	      _M_current = __backup;
418 	    }
419 	  else
420 	    _M_dfs(__match_mode, __state._M_next);
421 	}
422     }
423 
424   template<typename _BiIter, typename _Alloc, typename _TraitsT,
425 	   bool __dfs_mode>
426     void _Executor<_BiIter, _Alloc, _TraitsT, __dfs_mode>::
_M_handle_accept(_Match_mode __match_mode,_StateIdT)427     _M_handle_accept(_Match_mode __match_mode, _StateIdT)
428     {
429       if _GLIBCXX17_CONSTEXPR (__dfs_mode)
430 	{
431 	  __glibcxx_assert(!_M_has_sol);
432 	  if (__match_mode == _Match_mode::_Exact)
433 	    _M_has_sol = _M_current == _M_end;
434 	  else
435 	    _M_has_sol = true;
436 	  if (_M_current == _M_begin
437 	      && (_M_flags & regex_constants::match_not_null))
438 	    _M_has_sol = false;
439 	  if (_M_has_sol)
440 	    {
441 	      if (_M_nfa._M_flags & regex_constants::ECMAScript)
442 		_M_results = _M_cur_results;
443 	      else // POSIX
444 		{
445 		  __glibcxx_assert(_M_states._M_get_sol_pos());
446 		  // Here's POSIX's logic: match the longest one. However
447 		  // we never know which one (lhs or rhs of "|") is longer
448 		  // unless we try both of them and compare the results.
449 		  // The member variable _M_sol_pos records the end
450 		  // position of the last successful match. It's better
451 		  // to be larger, because POSIX regex is always greedy.
452 		  // TODO: This could be slow.
453 		  if (*_M_states._M_get_sol_pos() == _BiIter()
454 		      || std::distance(_M_begin,
455 				       *_M_states._M_get_sol_pos())
456 			 < std::distance(_M_begin, _M_current))
457 		    {
458 		      *_M_states._M_get_sol_pos() = _M_current;
459 		      _M_results = _M_cur_results;
460 		    }
461 		}
462 	    }
463 	}
464       else
465 	{
466 	  if (_M_current == _M_begin
467 	      && (_M_flags & regex_constants::match_not_null))
468 	    return;
469 	  if (__match_mode == _Match_mode::_Prefix || _M_current == _M_end)
470 	    if (!_M_has_sol)
471 	      {
472 		_M_has_sol = true;
473 		_M_results = _M_cur_results;
474 	      }
475 	}
476     }
477 
478   template<typename _BiIter, typename _Alloc, typename _TraitsT,
479 	   bool __dfs_mode>
480     void _Executor<_BiIter, _Alloc, _TraitsT, __dfs_mode>::
_M_handle_alternative(_Match_mode __match_mode,_StateIdT __i)481     _M_handle_alternative(_Match_mode __match_mode, _StateIdT __i)
482     {
483       const auto& __state = _M_nfa[__i];
484 
485       if (_M_nfa._M_flags & regex_constants::ECMAScript)
486 	{
487 	  // TODO: Fix BFS support. It is wrong.
488 	  _M_dfs(__match_mode, __state._M_alt);
489 	  // Pick lhs if it matches. Only try rhs if it doesn't.
490 	  if (!_M_has_sol)
491 	    _M_dfs(__match_mode, __state._M_next);
492 	}
493       else
494 	{
495 	  // Try both and compare the result.
496 	  // See "case _S_opcode_accept:" handling above.
497 	  _M_dfs(__match_mode, __state._M_alt);
498 	  auto __has_sol = _M_has_sol;
499 	  _M_has_sol = false;
500 	  _M_dfs(__match_mode, __state._M_next);
501 	  _M_has_sol |= __has_sol;
502 	}
503     }
504 
505   template<typename _BiIter, typename _Alloc, typename _TraitsT,
506 	   bool __dfs_mode>
507     void _Executor<_BiIter, _Alloc, _TraitsT, __dfs_mode>::
_M_dfs(_Match_mode __match_mode,_StateIdT __i)508     _M_dfs(_Match_mode __match_mode, _StateIdT __i)
509     {
510       if (_M_states._M_visited(__i))
511 	return;
512 
513       switch (_M_nfa[__i]._M_opcode())
514 	{
515 	case _S_opcode_repeat:
516 	  _M_handle_repeat(__match_mode, __i); break;
517 	case _S_opcode_subexpr_begin:
518 	  _M_handle_subexpr_begin(__match_mode, __i); break;
519 	case _S_opcode_subexpr_end:
520 	  _M_handle_subexpr_end(__match_mode, __i); break;
521 	case _S_opcode_line_begin_assertion:
522 	  _M_handle_line_begin_assertion(__match_mode, __i); break;
523 	case _S_opcode_line_end_assertion:
524 	  _M_handle_line_end_assertion(__match_mode, __i); break;
525 	case _S_opcode_word_boundary:
526 	  _M_handle_word_boundary(__match_mode, __i); break;
527 	case _S_opcode_subexpr_lookahead:
528 	  _M_handle_subexpr_lookahead(__match_mode, __i); break;
529 	case _S_opcode_match:
530 	  _M_handle_match(__match_mode, __i); break;
531 	case _S_opcode_backref:
532 	  _M_handle_backref(__match_mode, __i); break;
533 	case _S_opcode_accept:
534 	  _M_handle_accept(__match_mode, __i); break;
535 	case _S_opcode_alternative:
536 	  _M_handle_alternative(__match_mode, __i); break;
537 	default:
538 	  __glibcxx_assert(false);
539 	}
540     }
541 
542   // Return whether now is at some word boundary.
543   template<typename _BiIter, typename _Alloc, typename _TraitsT,
544 	   bool __dfs_mode>
545     bool _Executor<_BiIter, _Alloc, _TraitsT, __dfs_mode>::
_M_word_boundary() const546     _M_word_boundary() const
547     {
548       if (_M_current == _M_begin && (_M_flags & regex_constants::match_not_bow))
549 	return false;
550       if (_M_current == _M_end && (_M_flags & regex_constants::match_not_eow))
551 	return false;
552 
553       bool __left_is_word = false;
554       if (_M_current != _M_begin
555 	  || (_M_flags & regex_constants::match_prev_avail))
556 	{
557 	  auto __prev = _M_current;
558 	  if (_M_is_word(*std::prev(__prev)))
559 	    __left_is_word = true;
560 	}
561       bool __right_is_word =
562         _M_current != _M_end && _M_is_word(*_M_current);
563 
564       return __left_is_word != __right_is_word;
565     }
566 } // namespace __detail
567 
568 _GLIBCXX_END_NAMESPACE_VERSION
569 } // namespace
570