xapian-core/matcher/msetpostlist.cc

   1 /** @file msetpostlist.cc
   2  *  @brief PostList returning entries from an MSet
   3  */
   4 /* Copyright (C) 2006,2007,2009,2010,2011,2015 Olly Betts
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (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 "msetpostlist.h"
  24
  25 #include "debuglog.h"
  26 #include "omassert.h"
  27
  28 #include "xapian/error.h"
  29
  30 using namespace std;
  31
  32 Xapian::doccount
  33 MSetPostList::get_termfreq_min() const
  34 {
  35     LOGCALL(MATCH, Xapian::doccount, "MSetPostList::get_termfreq_min", NO_ARGS);
  36     RETURN(mset_internal->matches_lower_bound);
  37 }
  38
  39 Xapian::doccount
  40 MSetPostList::get_termfreq_est() const
  41 {
  42     LOGCALL(MATCH, Xapian::doccount, "MSetPostList::get_termfreq_est", NO_ARGS);
  43     RETURN(mset_internal->matches_estimated);
  44 }
  45
  46 Xapian::doccount
  47 MSetPostList::get_termfreq_max() const
  48 {
  49     LOGCALL(MATCH, Xapian::doccount, "MSetPostList::get_termfreq_max", NO_ARGS);
  50     RETURN(mset_internal->matches_upper_bound);
  51 }
  52
  53 double
  54 MSetPostList::get_maxweight() const
  55 {
  56     LOGCALL(MATCH, double, "MSetPostList::get_maxweight", NO_ARGS);
  57     // If we've not started, return max_possible from our MSet so that this
  58     // value gets used to set max_possible in the combined MSet.
  59     if (cursor == -1) RETURN(mset_internal->max_possible);
  60
  61     // If the MSet is sorted in descending weight order, then the maxweight we
  62     // can return from now on is the weight of the current item.
  63     if (decreasing_relevance) {
  64         // FIXME: This is actually a reduction in the maxweight...
  65         if (at_end()) RETURN(0);
  66         RETURN(mset_internal->items[cursor].wt);
  67     }
  68
  69     // Otherwise max_attained is the best answer we can give.
  70     RETURN(mset_internal->max_attained);
  71 }
  72
  73 Xapian::docid
  74 MSetPostList::get_docid() const
  75 {
  76     LOGCALL(MATCH, Xapian::docid, "MSetPostList::get_docid", NO_ARGS);
  77     Assert(cursor != -1);
  78     RETURN(mset_internal->items[cursor].did);
  79 }
  80
  81 double
  82 MSetPostList::get_weight() const
  83 {
  84     LOGCALL(MATCH, double, "MSetPostList::get_weight", NO_ARGS);
  85     Assert(cursor != -1);
  86     RETURN(mset_internal->items[cursor].wt);
  87 }
  88
  89 const string *
  90 MSetPostList::get_sort_key() const
  91 {
  92     LOGCALL(MATCH, const string *, "MSetPostList::get_sort_key", NO_ARGS);
  93     Assert(cursor != -1);
  94     RETURN(&mset_internal->items[cursor].sort_key);
  95 }
  96
  97 const string *
  98 MSetPostList::get_collapse_key() const
  99 {
 100     LOGCALL(MATCH, const string *, "MSetPostList::get_collapse_key", NO_ARGS);
 101     Assert(cursor != -1);
 102     RETURN(&mset_internal->items[cursor].collapse_key);
 103 }
 104
 105 Xapian::termcount
 106 MSetPostList::get_doclength() const
 107 {
 108     throw Xapian::UnimplementedError("MSetPostList::get_doclength() unimplemented");
 109 }
 110
 111 Xapian::termcount
 112 MSetPostList::get_unique_terms() const
 113 {
 114     throw Xapian::UnimplementedError("MSetPostList::get_unique_terms() unimplemented");
 115 }
 116
 117 double
 118 MSetPostList::recalc_maxweight()
 119 {
 120     LOGCALL(MATCH, double, "MSetPostList::recalc_maxweight", NO_ARGS);
 121     RETURN(MSetPostList::get_maxweight());
 122 }
 123
 124 PostList *
 125 MSetPostList::next(double w_min)
 126 {
 127     LOGCALL(MATCH, PostList *, "MSetPostList::next", w_min);
 128     Assert(cursor == -1 || !at_end());
 129     ++cursor;
 130     if (decreasing_relevance) {
 131         // MSet items are in decreasing weight order, so if the current item
 132         // doesn't have enough weight, none of the remaining items will, so
 133         // skip straight to the end.
 134         if (!at_end() && mset_internal->items[cursor].wt < w_min)
 135             cursor = mset_internal->items.size();
 136     } else {
 137         // Otherwise, skip to the next entry with enough weight.
 138         while (!at_end() && mset_internal->items[cursor].wt < w_min)
 139             ++cursor;
 140     }
 141     RETURN(NULL);
 142 }
 143
 144 PostList *
 145 MSetPostList::skip_to(Xapian::docid, double)
 146 {
 147     // The usual semantics of skip_to don't make sense since MSetPostList
 148     // returns documents in MSet order rather than docid order like other
 149     // PostLists do.
 150     throw Xapian::InvalidOperationError("MSetPostList::skip_to not meaningful");
 151 }
 152
 153 bool
 154 MSetPostList::at_end() const
 155 {
 156     LOGCALL(MATCH, bool, "MSetPostList::at_end", NO_ARGS);
 157     Assert(cursor != -1);
 158     RETURN(size_t(cursor) >= mset_internal->items.size());
 159 }
 160
 161 string
 162 MSetPostList::get_description() const
 163 {
 164     string desc("(MSet ");
 165     desc += mset_internal->get_description();
 166     desc += ')';
 167     return desc;
 168 }