xapian-core/backends/contiguousalldocspostlist.h

   1 /** @file contiguousalldocspostlist.h
   2  * @brief Iterate all document ids when they form a contiguous range.
   3  */
   4 /* Copyright (C) 2007,2008,2009,2011 Olly Betts
   5  * Copyright (C) 2009 Lemur Consulting Ltd
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
  20  */
  21
  22 #ifndef XAPIAN_INCLUDED_CONTIGUOUSALLDOCSPOSTLIST_H
  23 #define XAPIAN_INCLUDED_CONTIGUOUSALLDOCSPOSTLIST_H
  24
  25 #include <string>
  26
  27 #include "database.h"
  28 #include "api/leafpostlist.h"
  29
  30 /// A PostList iteratating all docids when they form a contiguous range.
  31 class ContiguousAllDocsPostList : public LeafPostList {
  32     /// Don't allow assignment.
  33     void operator=(const ContiguousAllDocsPostList &);
  34
  35     /// Don't allow copying.
  36     ContiguousAllDocsPostList(const ContiguousAllDocsPostList &);
  37
  38     /// The database we're iterating over.
  39     Xapian::Internal::intrusive_ptr<const Xapian::Database::Internal> db;
  40
  41     /// The current document id.
  42     Xapian::docid did;
  43
  44     /// The number of documents in the database.
  45     Xapian::doccount doccount;
  46
  47   public:
  48     /// Constructor.
  49     ContiguousAllDocsPostList(Xapian::Internal::intrusive_ptr<const Xapian::Database::Internal> db_,
  50                               Xapian::doccount doccount_)
  51         : LeafPostList(std::string()),
  52           db(db_), did(0), doccount(doccount_) { }
  53
  54     /** Return the term frequency.
  55      *
  56      *  For an all documents postlist, this is the number of documents in the
  57      *  database.
  58      */
  59     Xapian::doccount get_termfreq() const;
  60
  61     /// Return the current docid.
  62     Xapian::docid get_docid() const;
  63
  64     /// Return the length of current document.
  65     Xapian::termcount get_doclength() const;
  66
  67     /// Return the number of unique terms.
  68     Xapian::termcount get_unique_terms() const;
  69
  70     /// Always return 1 (wdf isn't totally meaningful for us).
  71     Xapian::termcount get_wdf() const;
  72
  73     /// Throws InvalidOperationError.
  74     PositionList *read_position_list();
  75
  76     /// Throws InvalidOperationError.
  77     PositionList * open_position_list() const;
  78
  79     /// Advance to the next document.
  80     PostList * next(double w_min);
  81
  82     /// Skip ahead to next document with docid >= target.
  83     PostList * skip_to(Xapian::docid target, double w_min);
  84
  85     /// Return true if and only if we're off the end of the list.
  86     bool at_end() const;
  87
  88     /// Return a string description of this object.
  89     std::string get_description() const;
  90 };
  91
  92 #endif // XAPIAN_INCLUDED_CONTIGUOUSALLDOCSPOSTLIST_H