text: // Debugging iterator implementation (out of line) -*- C++ -*-
  
  // Copyright (C) 2003, 2004, 2005, 2006
  // 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 2, 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 COPYING.  If not, write to the Free
  // Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
  // USA.
  
  // As a special exception, you may use this file as part of a free software
  // library without restriction.  Specifically, if other files instantiate
  // templates or use macros or inline functions from this file, or you compile
  // this file and link it with other files to produce an executable, this
  // file does not by itself cause the resulting executable to be covered by
  // the GNU General Public License.  This exception does not however
  // invalidate any other reasons why the executable file might be covered by
  // the GNU General Public License.
  
  /** @file debug/safe_iterator.tcc
   *  This file is a GNU debug extension to the Standard C++ Library.
   */
  
  #ifndef _GLIBCXX_DEBUG_SAFE_ITERATOR_TCC
  #define _GLIBCXX_DEBUG_SAFE_ITERATOR_TCC 1
  
  namespace __gnu_debug
  {
    template<typename _Iterator, typename _Sequence>
      bool
      _Safe_iterator<_Iterator, _Sequence>::
      _M_can_advance(const difference_type& __n) const
      {
        typedef typename _Sequence::const_iterator const_iterator;
  
        if (this->_M_singular())
  	return false;
        if (__n == 0)
  	return true;
        if (__n < 0)
  	{
  	  const_iterator __begin =
  	    static_cast<const _Sequence*>(_M_sequence)->begin();
  	  std::pair<difference_type, _Distance_precision> __dist =
  	    this->_M_get_distance(__begin, *this);
  	  bool __ok =  (__dist.second == __dp_exact && __dist.first >= -__n
  			|| __dist.second != __dp_exact && __dist.first > 0);
  	  return __ok;
  	}
        else
  	{
  	  const_iterator __end =
  	    static_cast<const _Sequence*>(_M_sequence)->end();
  	  std::pair<difference_type, _Distance_precision> __dist =
  	    this->_M_get_distance(*this, __end);
  	  bool __ok = (__dist.second == __dp_exact && __dist.first >= __n
  		       || __dist.second != __dp_exact && __dist.first > 0);
  	  return __ok;
  	}
      }
  
    template<typename _Iterator, typename _Sequence>
      template<typename _Other>
        bool
        _Safe_iterator<_Iterator, _Sequence>::
        _M_valid_range(const _Safe_iterator<_Other, _Sequence>& __rhs) const
        {
  	if (!_M_can_compare(__rhs))
  	  return false;
  
  	/* Determine if we can order the iterators without the help of
  	   the container */
  	std::pair<difference_type, _Distance_precision> __dist =
  	  this->_M_get_distance(*this, __rhs);
  	switch (__dist.second) {
  	case __dp_equality:
  	  if (__dist.first == 0)
  	    return true;
  	  break;
  
  	case __dp_sign:
  	case __dp_exact:
  	  return __dist.first >= 0;
  	}
  
  	/* We can only test for equality, but check if one of the
  	   iterators is at an extreme. */
  	if (_M_is_begin() || __rhs._M_is_end())
  	  return true;
  	else if (_M_is_end() || __rhs._M_is_begin())
  	  return false;
  
  	// Assume that this is a valid range; we can't check anything else
  	return true;
        }
  
    template<typename _Iterator, typename _Sequence>
      void
      _Safe_iterator<_Iterator, _Sequence>::
      _M_invalidate()
      {
        __gnu_cxx::__scoped_lock sentry(this->_M_get_mutex());
        _M_invalidate_single();
      }
  
    template<typename _Iterator, typename _Sequence>
      void
      _Safe_iterator<_Iterator, _Sequence>::
      _M_invalidate_single()
      {
        typedef typename _Sequence::iterator iterator;
        typedef typename _Sequence::const_iterator const_iterator;
  
        if (!this->_M_singular())
  	{
  	  for (_Safe_iterator_base* __iter = _M_sequence->_M_iterators;
  	       __iter; __iter = __iter->_M_next)
  	    {
  	      iterator* __victim = static_cast<iterator*>(__iter);
  	      if (this->base() == __victim->base())
  		__victim->_M_version = 0;
  	    }
  
  	  for (_Safe_iterator_base* __iter2 = _M_sequence->_M_const_iterators;
  	       __iter2; __iter2 = __iter2->_M_next)
  	    {
  	      const_iterator* __victim = static_cast<const_iterator*>(__iter2);
  	      if (__victim->base() == this->base())
  		__victim->_M_version = 0;
  	    }
  	  _M_version = 0;
  	}
      }
  } // namespace __gnu_debug
  
  #endif
  
  