xapian-core/backends/contiguousalldocspostlist.cc

   1 /** @file
   2  * @brief Iterate all document ids when they form a contiguous range.
   3  */
   4 /* Copyright (C) 2007,2008,2009,2011,2017 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 <string>
  24
  25 #include "contiguousalldocspostlist.h"
  26
  27 #include "omassert.h"
  28 #include "str.h"
  29
  30 using namespace std;
  31
  32 Xapian::docid
  33 ContiguousAllDocsPostList::get_docid() const
  34 {
  35     Assert(did != 0);
  36     return did;
  37 }
  38
  39 Xapian::termcount
  40 ContiguousAllDocsPostList::get_wdf() const
  41 {
  42     Assert(did != 0);
  43     return 1;
  44 }
  45
  46 PositionList *
  47 ContiguousAllDocsPostList::read_position_list()
  48 {
  49     // Throws the same exception.
  50     return ContiguousAllDocsPostList::open_position_list();
  51 }
  52
  53 PositionList *
  54 ContiguousAllDocsPostList::open_position_list() const
  55 {
  56     throw Xapian::InvalidOperationError("Position lists not meaningful for ContiguousAllDocsPostList");
  57 }
  58
  59 PostList *
  60 ContiguousAllDocsPostList::next(double)
  61 {
  62     // Docids are contiguous from 1 so termfreq gives the highest docid.
  63     if (did == termfreq) {
  64         did = 0;
  65     } else {
  66         ++did;
  67     }
  68     return NULL;
  69 }
  70
  71 PostList *
  72 ContiguousAllDocsPostList::skip_to(Xapian::docid target, double)
  73 {
  74     if (target > did) {
  75         // Docids are contiguous from 1 so termfreq gives the highest docid.
  76         if (target > termfreq) {
  77             did = 0;
  78         } else {
  79             did = target;
  80         }
  81     }
  82     return NULL;
  83 }
  84
  85 bool
  86 ContiguousAllDocsPostList::at_end() const
  87 {
  88     return did == 0;
  89 }
  90
  91 Xapian::termcount
  92 ContiguousAllDocsPostList::get_wdf_upper_bound() const
  93 {
  94     return 1;
  95 }
  96
  97 string
  98 ContiguousAllDocsPostList::get_description() const
  99 {
 100     string msg("ContiguousAllDocsPostList(1..");
 101     msg += str(termfreq);
 102     msg += ')';
 103     return msg;
 104 }