xapian-core/matcher/extraweightpostlist.h

   1 /** @file extraweightpostlist.h
   2  * @brief PostList which adds on a term-independent weight contribution
   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_EXTRAWEIGHTPOSTLIST_H
  22 #define XAPIAN_INCLUDED_EXTRAWEIGHTPOSTLIST_H
  23
  24 #include "wrapperpostlist.h"
  25
  26 namespace Xapian {
  27 class Weight;
  28 }
  29
  30 class PostListTree;
  31
  32 /// PostList which adds on a term-independent weight contribution
  33 class ExtraWeightPostList : public WrapperPostList {
  34     /// Don't allow assignment.
  35     void operator=(const ExtraWeightPostList&) = delete;
  36
  37     /// Don't allow copying.
  38     ExtraWeightPostList(const ExtraWeightPostList&) = delete;
  39
  40     Xapian::Weight* weight;
  41
  42     PostListTree* pltree;
  43
  44     double max_extra;
  45
  46   public:
  47     ExtraWeightPostList(PostList* pl_,
  48                         Xapian::Weight* weight_,
  49                         PostListTree* pltree_)
  50         : WrapperPostList(pl_),
  51           weight(weight_),
  52           pltree(pltree_),
  53           max_extra(weight->get_maxextra()) {}
  54
  55     ~ExtraWeightPostList() {
  56         delete weight;
  57     }
  58
  59     double get_weight(Xapian::termcount doclen,
  60                       Xapian::termcount unique_terms) const;
  61
  62     double recalc_maxweight();
  63
  64     PostList* next(double w_min);
  65
  66     PostList* skip_to(Xapian::docid, double w_min);
  67
  68     std::string get_description() const;
  69 };
  70
  71 #endif // XAPIAN_INCLUDED_EXTRAWEIGHTPOSTLIST_H