root / tags / 1.0.8 / xapian-core / backends / flint / contiguousalldocspostlist.h

/** @file contiguousalldocspostlist.h
 * @brief Iterate all document ids when they form a contiguous range.
 */
/* Copyright (C) 2007 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_INCLUDED_FLINT_CONTIGUOUSALLDOCSPOSTLIST_H
#define XAPIAN_INCLUDED_FLINT_CONTIGUOUSALLDOCSPOSTLIST_H

#include <string>

#include "database.h"
#include "leafpostlist.h"

/// A PostList iteratating all docids when they form a contiguous range.
class ContiguousAllDocsPostList : public LeafPostList {
    /// Don't allow assignment.
    void operator=(const ContiguousAllDocsPostList &);

    /// Don't allow copying.
    ContiguousAllDocsPostList(const ContiguousAllDocsPostList &);

    /// The database we're iterating over.
    Xapian::Internal::RefCntPtr<const Xapian::Database::Internal> db;

    /// The current document id.
    Xapian::docid did;

    /// The number of documents in the database.
    Xapian::doccount doccount;

  public:
    /// Constructor.
    ContiguousAllDocsPostList(Xapian::Internal::RefCntPtr<const Xapian::Database::Internal> db_,
                              Xapian::doccount doccount_)
        : db(db_), did(0), doccount(doccount_) { }

    /// Destructor.
    ~ContiguousAllDocsPostList();

    /** Return the term frequency.
     *
     *  For an all documents postlist, this is the number of documents in the database.
     */
    Xapian::doccount get_termfreq() const;

    /// Return the current docid.
    Xapian::docid get_docid() const;

    /// Return the length of current document.
    Xapian::doclength get_doclength() const;

    /// Always return 1 (wdf isn't totally meaningful for us).
    Xapian::termcount get_wdf() const;

    /// Throws InvalidOperationError.
    PositionList *read_position_list();

    /// Throws InvalidOperationError.
    PositionList * open_position_list() const;

    /// Advance to the next document.
    PostList * next(Xapian::weight w_min);

    /// Skip ahead to next document with docid >= target.
    PostList * skip_to(Xapian::docid target, Xapian::weight w_min);

    /// Return true if and only if we're off the end of the list.
    bool at_end() const;

    /// Return a string description of this object.
    std::string get_description() const;
};

#endif // XAPIAN_INCLUDED_FLINT_CONTIGUOUSALLDOCSPOSTLIST_H