include/xapian/postingiterator.h

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/* Copyright 1999,2000,2001 BrightStation PLC
 * Copyright 2002 Ananova Ltd
 * Copyright 2003,2004,2005,2007 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_POSTINGITERATOR_H
#define XAPIAN_INCLUDED_POSTINGITERATOR_H

#include <iterator>
#include <string>

#include <xapian/base.h>
#include <xapian/types.h>
#include <xapian/positioniterator.h>
#include <xapian/visibility.h>

namespace Xapian {

class Database;

class DocIDWrapper {
    private:
        docid did;
    public:
        explicit DocIDWrapper(docid did_) : did(did_) { }
        docid operator*() const { return did; }
};

class XAPIAN_VISIBILITY_DEFAULT PostingIterator {
    public:
        class Internal;
        Xapian::Internal::RefCntPtr<Internal> internal;

    private:
        friend class Database; // So Database can construct us

        explicit PostingIterator(Internal *internal_);

    public:
        friend bool operator==(const PostingIterator &a,
                               const PostingIterator &b);

        PostingIterator();

        ~PostingIterator();

        PostingIterator(const PostingIterator &other);

        void operator=(const PostingIterator &other);

        PostingIterator & operator++();

        DocIDWrapper operator++(int) {
            Xapian::docid tmp = **this;
            operator++();
            return DocIDWrapper(tmp);
        }

        void skip_to(Xapian::docid did);

// Get the weight of the posting at the current position: will
// need to set a weight object for this to work.
// Xapian::weight get_weight() const;

        Xapian::docid operator *() const;

        Xapian::doclength get_doclength() const;

        Xapian::termcount get_wdf() const;

        PositionIterator positionlist_begin() const;

        PositionIterator positionlist_end() const {
            return PositionIterator(NULL);
        }

        // Don't expose these methods here.  A container iterator doesn't
        // provide a method to find the size of the container...
        // Xapian::doccount get_termfreq() const;
        // Xapian::termcount get_collection_freq() const;

        std::string get_description() const;


        typedef std::input_iterator_tag iterator_category;
        typedef Xapian::docid value_type;
        typedef Xapian::doccount_diff difference_type;
        typedef Xapian::docid * pointer;
        typedef Xapian::docid & reference;
};

inline bool operator==(const PostingIterator &a, const PostingIterator &b)
{
    return (a.internal.get() == b.internal.get());
}

inline bool operator!=(const PostingIterator &a, const PostingIterator &b)
{
    return !(a == b);
}

}

#endif /* XAPIAN_INCLUDED_POSTINGITERATOR_H */

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