xapian-core/matcher/orpositionlist.h

   1 /** @file orpositionlist.h
   2  * @brief Merge two PositionList objects using an OR operation.
   3  */
   4 /* Copyright (C) 2007,2010,2017 Olly Betts
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License as
   8  * published by the Free Software Foundation; either version 2 of the
   9  * License, or (at your option) any later version.
  10  *
  11  * This program 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  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
  19  */
  20
  21 #ifndef XAPIAN_INCLUDED_ORPOSITIONLIST_H
  22 #define XAPIAN_INCLUDED_ORPOSITIONLIST_H
  23
  24 #include "backends/positionlist.h"
  25 #include "api/postlist.h"
  26
  27 #include "xapian/error.h"
  28 #include <algorithm>
  29 #include <vector>
  30
  31 class OrPositionList : public PositionList {
  32     /// The PositionList sub-objects.
  33     std::vector<PositionList*> pls;
  34
  35     /** Current positions of the subobjects.
  36      *
  37      *  This will be empty when this position list hasn't yet started.
  38      */
  39     std::vector<Xapian::termpos> current;
  40
  41     /// Current position of this object.
  42     Xapian::termpos current_pos;
  43
  44   public:
  45     OrPositionList() { }
  46
  47     PositionList* gather(PostList* pl) {
  48         pls.clear();
  49         current.clear();
  50         pl->gather_position_lists(this);
  51         if (pls.size() == 1)
  52             return pls[0];
  53         return this;
  54     }
  55
  56     void add_poslist(PositionList* poslist) {
  57         pls.push_back(poslist);
  58     }
  59
  60     Xapian::termcount get_approx_size() const;
  61
  62     Xapian::termpos get_position() const;
  63
  64     bool next();
  65
  66     bool skip_to(Xapian::termpos termpos);
  67 };
  68
  69 #endif // XAPIAN_INCLUDED_ORPOSITIONLIST_H