Initial checkin of GCC 4.9.0 from trunk (r208799).

Change-Id: I48a3c08bb98542aa215912a75f03c0890e497dba

1 files changed, 374 insertions, 0 deletions

diff --git a/gcc-4.9/libstdc++-v3/include/bits/regex_executor.tcc b/gcc-4.9/libstdc++-v3/include/bits/regex_executor.tcc
new file mode 100644
index 0000000..68a5e04
--- /dev/null
+++ b/gcc-4.9/libstdc++-v3/include/bits/regex_executor.tcc
@@ -0,0 +1,374 @@
+// class template regex -*- C++ -*-
+
+// Copyright (C) 2013-2014 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_executor.tcc
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{regex}
+ */
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+namespace __detail
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  template<typename _BiIter, typename _Alloc, typename _TraitsT,
+    bool __dfs_mode>
+    bool _Executor<_BiIter, _Alloc, _TraitsT, __dfs_mode>::
+    _M_search()
+    {
+      if (_M_flags & regex_constants::match_continuous)
+	return _M_search_from_first();
+      auto __cur = _M_begin;
+      do
+	{
+	  _M_current = __cur;
+	  if (_M_main<false>())
+	    return true;
+	}
+      // Continue when __cur == _M_end
+      while (__cur++ != _M_end);
+      return false;
+    }
+
+  // This function operates in different modes, DFS mode or BFS mode, indicated
+  // by template parameter __dfs_mode. See _M_main for details.
+  //
+  // ------------------------------------------------------------
+  //
+  // DFS mode:
+  //
+  // It applies a Depth-First-Search (aka backtracking) on given NFA and input
+  // string.
+  // At the very beginning the executor stands in the start state, then it tries
+  // 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 don't, like assertion or other anchor nodes.
+  // When the input is exhausted and/or the current state is an accepting state,
+  // the whole executor returns true.
+  //
+  // TODO: This approach is exponentially slow for certain input.
+  //       Try to compile the NFA to a DFA.
+  //
+  // Time complexity: \Omega(match_length), O(2^(_M_nfa.size()))
+  // Space complexity: \theta(match_results.size() + match_length)
+  //
+  // ------------------------------------------------------------
+  //
+  // BFS mode:
+  //
+  // Russ Cox's article (http://swtch.com/~rsc/regexp/regexp1.html)
+  // explained this algorithm clearly.
+  //
+  // It first computes epsilon closure (states that can be achieved without
+  // consuming characters) for every state that's still matching,
+  // using the same DFS algorithm, but doesn't re-enter states (find a true in
+  // _M_visited), nor follows _S_opcode_match.
+  //
+  // Then apply DFS using every _S_opcode_match (in _M_match_queue) as the start
+  // state.
+  //
+  // It significantly reduces potential duplicate states, so has a better
+  // upper bound; but it requires more overhead.
+  //
+  // Time complexity: \Omega(match_length * match_results.size())
+  //                  O(match_length * _M_nfa.size() * match_results.size())
+  // Space complexity: \Omega(_M_nfa.size() + match_results.size())
+  //                   O(_M_nfa.size() * match_results.size())
+  template<typename _BiIter, typename _Alloc, typename _TraitsT,
+    bool __dfs_mode>
+  template<bool __match_mode>
+    bool _Executor<_BiIter, _Alloc, _TraitsT, __dfs_mode>::
+    _M_main()
+    {
+      if (__dfs_mode)
+	{
+	  _M_has_sol = false;
+	  _M_cur_results = _M_results;
+	  _M_dfs<__match_mode>(_M_start_state);
+	  return _M_has_sol;
+	}
+      else
+	{
+	  _M_match_queue->push_back(make_pair(_M_start_state, _M_results));
+	  bool __ret = false;
+	  while (1)
+	    {
+	      _M_has_sol = false;
+	      if (_M_match_queue->empty())
+		break;
+	      _M_visited->assign(_M_visited->size(), false);
+	      auto _M_old_queue = std::move(*_M_match_queue);
+	      for (auto __task : _M_old_queue)
+		{
+		  _M_cur_results = __task.second;
+		  _M_dfs<__match_mode>(__task.first);
+		}
+	      if (!__match_mode)
+		__ret |= _M_has_sol;
+	      if (_M_current == _M_end)
+		break;
+	      ++_M_current;
+	    }
+	  if (__match_mode)
+	    __ret = _M_has_sol;
+	  return __ret;
+	}
+    }
+
+  // Return whether now match the given sub-NFA.
+  template<typename _BiIter, typename _Alloc, typename _TraitsT,
+    bool __dfs_mode>
+    bool _Executor<_BiIter, _Alloc, _TraitsT, __dfs_mode>::
+    _M_lookahead(_State<_TraitsT> __state)
+    {
+      _ResultsVec __what(_M_cur_results.size());
+      auto __sub = std::unique_ptr<_Executor>(new _Executor(_M_current,
+							    _M_end,
+							    __what,
+							    _M_re,
+							    _M_flags));
+      __sub->_M_start_state = __state._M_alt;
+      if (__sub->_M_search_from_first())
+	{
+	  for (size_t __i = 0; __i < __what.size(); __i++)
+	    if (__what[__i].matched)
+	      _M_cur_results[__i] = __what[__i];
+	  return true;
+	}
+      return false;
+    }
+
+  // TODO: Use a function vector to dispatch, instead of using switch-case.
+  template<typename _BiIter, typename _Alloc, typename _TraitsT,
+    bool __dfs_mode>
+  template<bool __match_mode>
+    void _Executor<_BiIter, _Alloc, _TraitsT, __dfs_mode>::
+    _M_dfs(_StateIdT __i)
+    {
+      if (!__dfs_mode)
+	{
+	  if ((*_M_visited)[__i])
+	    return;
+	  (*_M_visited)[__i] = true;
+	}
+
+      const auto& __state = _M_nfa[__i];
+      // Every change on _M_cur_results and _M_current will be rolled back after
+      // finishing the recursion step.
+      switch (__state._M_opcode)
+	{
+	// _M_alt branch is "match once more", while _M_next is "get me out
+	// of this quantifier". Executing _M_next first or _M_alt first don't
+	// mean the same thing, and we need to choose the correct order under
+	// given greedy mode.
+	case _S_opcode_alternative:
+	  // Greedy.
+	  if (!__state._M_neg)
+	    {
+	      // "Once more" is preferred in greedy mode.
+	      _M_dfs<__match_mode>(__state._M_alt);
+	      // If it's DFS executor and already accepted, we're done.
+	      if (!__dfs_mode || !_M_has_sol)
+		_M_dfs<__match_mode>(__state._M_next);
+	    }
+	  else // Non-greedy mode
+	    {
+	      if (__dfs_mode)
+		{
+		  // vice-versa.
+		  _M_dfs<__match_mode>(__state._M_next);
+		  if (!_M_has_sol)
+		    _M_dfs<__match_mode>(__state._M_alt);
+		}
+	      else
+		{
+		  // DON'T attempt anything, because there's already another
+		  // state with higher priority accepted. This state cannot be
+		  // better by attempting its next node.
+		  if (!_M_has_sol)
+		    {
+		      _M_dfs<__match_mode>(__state._M_next);
+		      // DON'T attempt anything if it's already accepted. An
+		      // accepted state *must* be better than a solution that
+		      // matches a non-greedy quantifier one more time.
+		      if (!_M_has_sol)
+			_M_dfs<__match_mode>(__state._M_alt);
+		    }
+		}
+	    }
+	  break;
+	case _S_opcode_subexpr_begin:
+	  // If there's nothing changed since last visit, do NOT continue.
+	  // This prevents the executor from get into infinite loop when using
+	  // "()*" to match "".
+	  if (!_M_cur_results[__state._M_subexpr].matched
+	      || _M_cur_results[__state._M_subexpr].first != _M_current)
+	    {
+	      auto& __res = _M_cur_results[__state._M_subexpr];
+	      auto __back = __res.first;
+	      __res.first = _M_current;
+	      _M_dfs<__match_mode>(__state._M_next);
+	      __res.first = __back;
+	    }
+	  break;
+	case _S_opcode_subexpr_end:
+	  if (_M_cur_results[__state._M_subexpr].second != _M_current
+	      || _M_cur_results[__state._M_subexpr].matched != true)
+	    {
+	      auto& __res = _M_cur_results[__state._M_subexpr];
+	      auto __back = __res;
+	      __res.second = _M_current;
+	      __res.matched = true;
+	      _M_dfs<__match_mode>(__state._M_next);
+	      __res = __back;
+	    }
+	  else
+	    _M_dfs<__match_mode>(__state._M_next);
+	  break;
+	case _S_opcode_line_begin_assertion:
+	  if (_M_at_begin())
+	    _M_dfs<__match_mode>(__state._M_next);
+	  break;
+	case _S_opcode_line_end_assertion:
+	  if (_M_at_end())
+	    _M_dfs<__match_mode>(__state._M_next);
+	  break;
+	case _S_opcode_word_boundary:
+	  if (_M_word_boundary(__state) == !__state._M_neg)
+	    _M_dfs<__match_mode>(__state._M_next);
+	  break;
+	// Here __state._M_alt offers a single start node for a sub-NFA.
+	// We recursively invoke our algorithm to match the sub-NFA.
+	case _S_opcode_subexpr_lookahead:
+	  if (_M_lookahead(__state) == !__state._M_neg)
+	    _M_dfs<__match_mode>(__state._M_next);
+	  break;
+	case _S_opcode_match:
+	  if (__dfs_mode)
+	    {
+	      if (_M_current != _M_end && __state._M_matches(*_M_current))
+		{
+		  ++_M_current;
+		  _M_dfs<__match_mode>(__state._M_next);
+		  --_M_current;
+		}
+	    }
+	  else
+	    if (__state._M_matches(*_M_current))
+	      _M_match_queue->push_back(make_pair(__state._M_next,
+						  _M_cur_results));
+	  break;
+	// First fetch the matched result from _M_cur_results as __submatch;
+	// then compare it with
+	// (_M_current, _M_current + (__submatch.second - __submatch.first)).
+	// If matched, keep going; else just return and try another state.
+	case _S_opcode_backref:
+	  {
+	    _GLIBCXX_DEBUG_ASSERT(__dfs_mode);
+	    auto& __submatch = _M_cur_results[__state._M_backref_index];
+	    if (!__submatch.matched)
+	      break;
+	    auto __last = _M_current;
+	    for (auto __tmp = __submatch.first;
+		 __last != _M_end && __tmp != __submatch.second;
+		 ++__tmp)
+	      ++__last;
+	    if (_M_re._M_traits.transform(__submatch.first,
+						__submatch.second)
+		== _M_re._M_traits.transform(_M_current, __last))
+	      {
+		if (__last != _M_current)
+		  {
+		    auto __backup = _M_current;
+		    _M_current = __last;
+		    _M_dfs<__match_mode>(__state._M_next);
+		    _M_current = __backup;
+		  }
+		else
+		  _M_dfs<__match_mode>(__state._M_next);
+	      }
+	  }
+	  break;
+	case _S_opcode_accept:
+	  if (__dfs_mode)
+	    {
+	      _GLIBCXX_DEBUG_ASSERT(!_M_has_sol);
+	      if (__match_mode)
+		_M_has_sol = _M_current == _M_end;
+	      else
+		_M_has_sol = true;
+	      if (_M_current == _M_begin
+		  && (_M_flags & regex_constants::match_not_null))
+		_M_has_sol = false;
+	      if (_M_has_sol)
+		_M_results = _M_cur_results;
+	    }
+	  else
+	    {
+	      if (_M_current == _M_begin
+		  && (_M_flags & regex_constants::match_not_null))
+		break;
+	      if (!__match_mode || _M_current == _M_end)
+		if (!_M_has_sol)
+		  {
+		    _M_has_sol = true;
+		    _M_results = _M_cur_results;
+		  }
+	    }
+	  break;
+	default:
+	  _GLIBCXX_DEBUG_ASSERT(false);
+	}
+    }
+
+  // Return whether now is at some word boundary.
+  template<typename _BiIter, typename _Alloc, typename _TraitsT,
+    bool __dfs_mode>
+    bool _Executor<_BiIter, _Alloc, _TraitsT, __dfs_mode>::
+    _M_word_boundary(_State<_TraitsT> __state) const
+    {
+      // By definition.
+      bool __ans = false;
+      auto __pre = _M_current;
+      --__pre;
+      if (!(_M_at_begin() && _M_at_end()))
+	{
+	  if (_M_at_begin())
+	    __ans = _M_is_word(*_M_current)
+	      && !(_M_flags & regex_constants::match_not_bow);
+	  else if (_M_at_end())
+	    __ans = _M_is_word(*__pre)
+	      && !(_M_flags & regex_constants::match_not_eow);
+	  else
+	    __ans = _M_is_word(*_M_current)
+	      != _M_is_word(*__pre);
+	}
+      return __ans;
+    }
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace __detail
+} // namespace