safe_iterator.tcc

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// Debugging iterator implementation (out of line) -*- C++ -*-

// Copyright (C) 2003, 2004, 2005, 2006, 2007, 2009, 2010
// 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 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_debug_iterator;
      typedef typename const_debug_iterator::iterator_type const_iterator;

      if (this->_M_singular())
    return false;
      if (__n == 0)
    return true;
      if (__n < 0)
    {
      const_iterator __begin = _M_get_sequence()->_M_base().begin();
      std::pair<difference_type, _Distance_precision> __dist =
        this->_M_get_distance(__begin, base());
      bool __ok =  ((__dist.second == __dp_exact && __dist.first >= -__n)
            || (__dist.second != __dp_exact && __dist.first > 0));
      return __ok;
    }
      else
    {
      const_iterator __end = _M_get_sequence()->_M_base().end();
      std::pair<difference_type, _Distance_precision> __dist =
        this->_M_get_distance(base(), __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(base(), __rhs.base());
    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. */
    /* Optim for classic [begin, it) or [it, end) ranges, limit checks
     * when code is valid. */
    if (_M_is_begin() || __rhs._M_is_end())
      return true;
    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;
      }
} // namespace __gnu_debug

#endif