text: /* Copyright (C) 2007-2013 Arjen G Lentz & Antony T Curtis for Open Query
  
     This program 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; version 2 of the License, or
     (at your option) any later version.
  
     This program 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 program; if not, write to the Free Software
     Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02111-1301 USA */
  
  /* ======================================================================
     Open Query Graph Computation Engine, based on a concept by Arjen Lentz
     v3 implementation by Antony Curtis, Arjen Lentz, Andrew McDonnell
     For more information, documentation, support, enhancement engineering,
     see http://openquery.com/graph or contact graph@openquery.com
     ======================================================================
  */
  
  #include "oqgraph_shim.h"
  
  bool oqgraph3::edge_iterator::seek()
  {
    if (!_graph->_cursor ||
        _graph->_rnd_pos > _offset ||
        _graph->_cursor != _graph->_rnd_cursor.operator->())
    {
      _graph->_rnd_pos= 0;
      _graph->_rnd_cursor= new cursor(_graph);
      if (_graph->_rnd_cursor->seek_to(boost::none, boost::none))
        _graph->_rnd_pos= size_t(-1);
    }
    while (_graph->_rnd_pos < _offset)
    {
      if (_graph->_rnd_cursor->seek_next())
      {
        _offset = size_t(-1);
        return true;
      }
      _graph->_rnd_pos++;
    }
    return false;
  }
  
  oqgraph3::edge_iterator::value_type oqgraph3::edge_iterator::operator*()
  {
    seek();
    return *_graph->_rnd_cursor;
  }
  
  bool oqgraph3::edge_iterator::operator==(const self& x)
  {
    if (_offset == size_t(-1) && x._offset != size_t(-1))
      return const_cast<edge_iterator&>(x).seek();
    if (_offset != size_t(-1) && x._offset == size_t(-1))
      return seek();
  
    return _offset == x._offset;
  }
  
  bool oqgraph3::edge_iterator::operator!=(const self& x)
  {
    if (_offset == size_t(-1) && x._offset != size_t(-1))
      return !const_cast<edge_iterator&>(x).seek();
    if (_offset != size_t(-1) && x._offset == size_t(-1))
      return !seek();
  
    return _offset != x._offset;
  }
  