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

   1 // Debugging iterator implementation (out of line) -*- C++ -*-
   2
   3 // Copyright (C) 2003-2014 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       if (this->_M_singular())
  40         return false;
  41       if (__n == 0)
  42         return true;
  43       if (__n < 0)
  44         {
  45           std::pair<difference_type, _Distance_precision> __dist =
  46             __get_distance(_M_get_sequence()->_M_base().begin(), base());
  47           bool __ok =  ((__dist.second == __dp_exact && __dist.first >= -__n)
  48                         || (__dist.second != __dp_exact && __dist.first > 0));
  49           return __ok;
  50         }
  51       else
  52         {
  53           std::pair<difference_type, _Distance_precision> __dist =
  54             __get_distance(base(), _M_get_sequence()->_M_base().end());
  55           bool __ok = ((__dist.second == __dp_exact && __dist.first >= __n)
  56                        || (__dist.second != __dp_exact && __dist.first > 0));
  57           return __ok;
  58         }
  59     }
  60
  61   template<typename _Iterator, typename _Sequence>
  62     bool
  63     _Safe_iterator<_Iterator, _Sequence>::
  64     _M_valid_range(const _Safe_iterator& __rhs) const
  65     {
  66       if (!_M_can_compare(__rhs))
  67         return false;
  68
  69       /* Determine if we can order the iterators without the help of
  70          the container */
  71       std::pair<difference_type, _Distance_precision> __dist =
  72         __get_distance(base(), __rhs.base());
  73       switch (__dist.second) {
  74       case __dp_equality:
  75         if (__dist.first == 0)
  76           return true;
  77         break;
  78
  79       case __dp_sign:
  80       case __dp_exact:
  81         return __dist.first >= 0;
  82       }
  83
  84       /* We can only test for equality, but check if one of the
  85          iterators is at an extreme. */
  86       /* Optim for classic [begin, it) or [it, end) ranges, limit checks
  87        * when code is valid.  Note, for the special case of forward_list,
  88        * before_begin replaces the role of begin.  */
  89       if (_M_is_beginnest() || __rhs._M_is_end())
  90         return true;
  91       if (_M_is_end() || __rhs._M_is_beginnest())
  92         return false;
  93
  94       // Assume that this is a valid range; we can't check anything else
  95       return true;
  96     }
  97 } // namespace __gnu_debug
  98
  99 #endif
 100