libstdc++-v3/include/debug/safe_iterator.tcc

   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