xapian-core/api/emptypostlist.cc

   1 /** @file emptypostlist.cc
   2  * @brief A PostList which contains no entries.
   3  */
   4 /* Copyright (C) 2009,2010,2011,2015 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 "emptypostlist.h"
  24
  25 #include "omassert.h"
  26
  27 using namespace std;
  28
  29 Xapian::doccount
  30 EmptyPostList::get_termfreq_min() const
  31 {
  32     return 0;
  33 }
  34
  35 Xapian::doccount
  36 EmptyPostList::get_termfreq_max() const
  37 {
  38     return 0;
  39 }
  40
  41 Xapian::doccount
  42 EmptyPostList::get_termfreq_est() const
  43 {
  44     return 0;
  45 }
  46
  47 // OP_WILDCARD which expands to no terms becomes EmptyPostList, and this is
  48 // needed if that is used under OP_SYNONYM.
  49 TermFreqs
  50 EmptyPostList::get_termfreq_est_using_stats(const Xapian::Weight::Internal &) const
  51 {
  52     return TermFreqs();
  53 }
  54
  55 double
  56 EmptyPostList::get_maxweight() const
  57 {
  58     return 0;
  59 }
  60
  61 Xapian::docid
  62 EmptyPostList::get_docid() const
  63 {
  64     Assert(false);
  65     return 0;
  66 }
  67
  68 Xapian::termcount
  69 EmptyPostList::get_doclength() const
  70 {
  71     return Xapian::termcount(EmptyPostList::get_docid());
  72 }
  73
  74 Xapian::termcount
  75 EmptyPostList::get_unique_terms() const
  76 {
  77     return Xapian::termcount(EmptyPostList::get_docid());
  78 }
  79
  80 double
  81 EmptyPostList::get_weight() const
  82 {
  83     Assert(false);
  84     return 0;
  85 }
  86
  87 bool
  88 EmptyPostList::at_end() const
  89 {
  90     return true;
  91 }
  92
  93 double
  94 EmptyPostList::recalc_maxweight()
  95 {
  96     return EmptyPostList::get_maxweight();
  97 }
  98
  99 PostList *
 100 EmptyPostList::next(double)
 101 {
 102     return NULL;
 103 }
 104
 105 PostList *
 106 EmptyPostList::skip_to(Xapian::docid, double)
 107 {
 108     return NULL;
 109 }
 110
 111 string
 112 EmptyPostList::get_description() const
 113 {
 114     return "EmptyPostList";
 115 }