xapian-core/matcher/orpostlist.h

   1 /** @file
   2  * @brief PostList class implementing Query::OP_OR
   3  */
   4 /* Copyright 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_ORPOSTLIST_H
  22 #define XAPIAN_INCLUDED_ORPOSTLIST_H
  23
  24 #include "backends/postlist.h"
  25
  26 class PostListTree;
  27
  28 /// PostList class implementing Query::OP_OR
  29 class OrPostList : public PostList {
  30     /// Don't allow assignment.
  31     void operator=(const OrPostList&) = delete;
  32
  33     /// Don't allow copying.
  34     OrPostList(const OrPostList&) = delete;
  35
  36     /** Left side.
  37      *
  38      *  We optimise assuming this side is more frequent, and so creators should
  39      *  try to set this side to the side with the higher estimated term
  40      *  frequency.
  41      */
  42     PostList* l;
  43
  44     /// Right side.
  45     PostList* r;
  46
  47     Xapian::docid l_did = 0;
  48
  49     Xapian::docid r_did = 0;
  50
  51     double l_max = 0;
  52
  53     double r_max = 0;
  54
  55     PostListTree* pltree;
  56
  57     PostList* decay_to_and(Xapian::docid did,
  58                            double w_min,
  59                            bool* valid_ptr = NULL);
  60
  61     PostList* decay_to_andmaybe(PostList* left,
  62                                 PostList* right,
  63                                 Xapian::docid did,
  64                                 double w_min,
  65                                 bool* valid_ptr = NULL);
  66
  67   public:
  68     OrPostList(PostList* left, PostList* right, PostListTree* pltree_);
  69
  70     ~OrPostList() {
  71         delete l;
  72         delete r;
  73     }
  74
  75     Xapian::docid get_docid() const;
  76
  77     double get_weight(Xapian::termcount doclen,
  78                       Xapian::termcount unique_terms,
  79                       Xapian::termcount wdfdocmax) const;
  80
  81     bool at_end() const;
  82
  83     double recalc_maxweight();
  84
  85     PostList* next(double w_min);
  86
  87     PostList* skip_to(Xapian::docid did, double w_min);
  88
  89     PostList* check(Xapian::docid did, double w_min, bool& valid);
  90
  91     void get_docid_range(Xapian::docid& first, Xapian::docid& last) const;
  92
  93     std::string get_description() const;
  94
  95     Xapian::termcount get_wdf() const;
  96
  97     Xapian::termcount count_matching_subqs() const;
  98
  99     void gather_position_lists(OrPositionList* orposlist);
 100 };
 101
 102 #endif // XAPIAN_INCLUDED_ORPOSTLIST_H