chert_positionlist.h

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/* Copyright (C) 2005,2006,2008,2009,2010,2011,2013 Olly Betts
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301
 * USA
 */

#ifndef XAPIAN_HGUARD_CHERT_POSITIONLIST_H
#define XAPIAN_HGUARD_CHERT_POSITIONLIST_H

#include <xapian/types.h>

#include "bitstream.h"
#include "chert_lazytable.h"
#include "pack.h"
#include "backends/positionlist.h"

#include <string>

using namespace std;

class ChertPositionListTable : public ChertLazyTable {
  public:
    static string make_key(Xapian::docid did, const string & term) {
        string key;
        C_pack_uint_preserving_sort(key, did);
        key += term;
        return key;
    }

    ChertPositionListTable(const string & dbdir, bool readonly)
        : ChertLazyTable("position", dbdir + "/position.", readonly,
                         DONT_COMPRESS) { }

    void set_positionlist(Xapian::docid did, const string & tname,
                          Xapian::PositionIterator pos,
                          const Xapian::PositionIterator &pos_end,
                          bool check_for_update);

    void delete_positionlist(Xapian::docid did, const string & tname) {
        del(make_key(did, tname));
    }

    Xapian::termcount positionlist_count(Xapian::docid did,
                                         const string & term) const;
};

class ChertPositionList : public PositionList {
    BitReader rd;

    Xapian::termpos current_pos;

    Xapian::termpos last;

    Xapian::termcount size;

    bool have_started;

    ChertPositionList(const ChertPositionList &);

    void operator=(const ChertPositionList &);

  public:
    ChertPositionList() { }

    ChertPositionList(const ChertTable * table, Xapian::docid did,
                      const string & tname) {
        (void)read_data(table, did, tname);
    }

    bool read_data(const ChertTable * table, Xapian::docid did,
                   const string & tname);

    Xapian::termcount get_approx_size() const;

    Xapian::termpos get_position() const;

    bool next();

    bool skip_to(Xapian::termpos termpos);
};

#endif /* XAPIAN_HGUARD_CHERT_POSITIONLIST_H */