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       1                 :            : /** @file extraweightpostlist.cc
       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                 :            : #include <config.h>
      22                 :            : 
      23                 :            : #include "extraweightpostlist.h"
      24                 :            : 
      25                 :            : #include "omassert.h"
      26                 :            : #include "postlisttree.h"
      27                 :            : #include "str.h"
      28                 :            : 
      29                 :            : using namespace std;
      30                 :            : 
      31                 :            : double
      32                 :       2125 : ExtraWeightPostList::get_weight(Xapian::termcount doclen,
      33                 :            :                                 Xapian::termcount unique_terms) const
      34                 :            : {
      35                 :            :     /* Weight::get_sumextra() takes two parameters (document length and number
      36                 :            :      * of unique terms) but none of the currently implemented weighting schemes
      37                 :            :      * actually use the latter - it was added because it's likely to be wanted
      38                 :            :      * at some point, and so that we got all the incompatible changes needed to
      39                 :            :      * add support for the number of unique terms over with in one go.
      40                 :            :      */
      41                 :       2125 :     double sum_extra = weight->get_sumextra(doclen, unique_terms);
      42                 :            :     AssertRel(sum_extra,<=,max_extra);
      43                 :       2125 :     return pl->get_weight(doclen, unique_terms) + sum_extra;
      44                 :            : }
      45                 :            : 
      46                 :            : double
      47                 :       1334 : ExtraWeightPostList::recalc_maxweight()
      48                 :            : {
      49                 :       1334 :     return pl->recalc_maxweight() + max_extra;
      50                 :            : }
      51                 :            : 
      52                 :            : PostList*
      53                 :       3459 : ExtraWeightPostList::next(double w_min)
      54                 :            : {
      55                 :       3459 :     PostList* res = pl->next(w_min - max_extra);
      56         [ +  + ]:       3459 :     if (res) {
      57         [ +  - ]:        422 :         delete pl;
      58                 :        422 :         pl = res;
      59                 :        422 :         pltree->force_recalc();
      60                 :            :     }
      61                 :       3459 :     return NULL;
      62                 :            : }
      63                 :            : 
      64                 :            : PostList*
      65                 :          0 : ExtraWeightPostList::skip_to(Xapian::docid, double)
      66                 :            : {
      67                 :            :     // ExtraWeightPostList's parent will be PostListTree which doesn't
      68                 :            :     // call skip_to() or check().
      69                 :            :     Assert(false);
      70                 :          0 :     return NULL;
      71                 :            : }
      72                 :            : 
      73                 :            : string
      74                 :          0 : ExtraWeightPostList::get_description() const
      75                 :            : {
      76         [ #  # ]:          0 :     string desc = "ExtraWeightPostList(";
      77 [ #  # ][ #  # ]:          0 :     desc += pl->get_description();
      78         [ #  # ]:          0 :     desc += ", max_extra=";
      79 [ #  # ][ #  # ]:          0 :     desc += str(max_extra);
      80         [ #  # ]:          0 :     desc += ')';
      81                 :          0 :     return desc;
      82                 :            : }