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      1 // Debugging iterator implementation (out of line) -*- C++ -*-
      2 
      3 // Copyright (C) 2003-2013 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 /** @file debug/safe_iterator.tcc
     26  *  This file is a GNU debug extension to the Standard C++ Library.
     27  */
     28 
     29 #ifndef _GLIBCXX_DEBUG_SAFE_ITERATOR_TCC
     30 #define _GLIBCXX_DEBUG_SAFE_ITERATOR_TCC 1
     31 
     32 namespace __gnu_debug
     33 {
     34   template<typename _Iterator, typename _Sequence>
     35     bool
     36     _Safe_iterator<_Iterator, _Sequence>::
     37     _M_can_advance(const difference_type& __n) const
     38     {
     39       typedef typename _Sequence::const_iterator const_debug_iterator;
     40       typedef typename const_debug_iterator::iterator_type const_iterator;
     41 
     42       if (this->_M_singular())
     43 	return false;
     44       if (__n == 0)
     45 	return true;
     46       if (__n < 0)
     47 	{
     48 	  const_iterator __begin = _M_get_sequence()->_M_base().begin();
     49 	  std::pair<difference_type, _Distance_precision> __dist =
     50 	    __get_distance(__begin, base());
     51 	  bool __ok =  ((__dist.second == __dp_exact && __dist.first >= -__n)
     52 			|| (__dist.second != __dp_exact && __dist.first > 0));
     53 	  return __ok;
     54 	}
     55       else
     56 	{
     57 	  const_iterator __end = _M_get_sequence()->_M_base().end();
     58 	  std::pair<difference_type, _Distance_precision> __dist =
     59 	    __get_distance(base(), __end);
     60 	  bool __ok = ((__dist.second == __dp_exact && __dist.first >= __n)
     61 		       || (__dist.second != __dp_exact && __dist.first > 0));
     62 	  return __ok;
     63 	}
     64     }
     65 
     66   template<typename _Iterator, typename _Sequence>
     67     template<typename _Other>
     68       bool
     69       _Safe_iterator<_Iterator, _Sequence>::
     70       _M_valid_range(const _Safe_iterator<_Other, _Sequence>& __rhs) const
     71       {
     72 	if (!_M_can_compare(__rhs))
     73 	  return false;
     74 
     75 	/* Determine if we can order the iterators without the help of
     76 	   the container */
     77 	std::pair<difference_type, _Distance_precision> __dist =
     78 	  __get_distance(base(), __rhs.base());
     79 	switch (__dist.second) {
     80 	case __dp_equality:
     81 	  if (__dist.first == 0)
     82 	    return true;
     83 	  break;
     84 
     85 	case __dp_sign:
     86 	case __dp_exact:
     87 	  return __dist.first >= 0;
     88 	}
     89 
     90 	/* We can only test for equality, but check if one of the
     91 	   iterators is at an extreme. */
     92 	/* Optim for classic [begin, it) or [it, end) ranges, limit checks
     93 	 * when code is valid.  Note, for the special case of forward_list,
     94 	 * before_begin replaces the role of begin.  */ 
     95 	if (_M_is_beginnest() || __rhs._M_is_end())
     96 	  return true;
     97 	if (_M_is_end() || __rhs._M_is_beginnest())
     98 	  return false;
     99 
    100 	// Assume that this is a valid range; we can't check anything else
    101 	return true;
    102       }
    103 } // namespace __gnu_debug
    104 
    105 #endif
    106 
    107