include/xapian/positioniterator.h

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/* Copyright 1999,2000,2001 BrightStation PLC
 * Copyright 2002 Ananova Ltd
 * Copyright 2003,2004,2007 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_POSITIONITERATOR_H
#define XAPIAN_INCLUDED_POSITIONITERATOR_H

#include <iterator>
#include <string>

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

namespace Xapian {

class Database;
class PostingIterator;
class TermIterator;

class TermPosWrapper {
    private:
        termpos pos;
    public:
        explicit TermPosWrapper(termpos pos_) : pos(pos_) { }
        termpos operator*() const { return pos; }
};

class XAPIAN_VISIBILITY_DEFAULT PositionIterator {
    private:
        // friend classes which need to be able to construct us
        friend class PostingIterator;
        friend class TermIterator;
        friend class Database;

    public:
        class Internal;
        Xapian::Internal::RefCntPtr<Internal> internal;

        friend bool operator==(const PositionIterator &a, const PositionIterator &b);

        // FIXME: ought to be private
        explicit PositionIterator(Internal *internal_);

        PositionIterator();

        ~PositionIterator();

        PositionIterator(const PositionIterator &o);

        void operator=(const PositionIterator &o);

        Xapian::termpos operator *() const;

        PositionIterator & operator++();

        TermPosWrapper operator++(int) {
            Xapian::termpos tmp = **this;
            operator++();
            return TermPosWrapper(tmp);
        }

        // extra method, not required for an input_iterator
        void skip_to(Xapian::termpos pos);

        std::string get_description() const;

        // Allow use as an STL iterator
        typedef std::input_iterator_tag iterator_category;
        typedef Xapian::termpos value_type;
        typedef Xapian::termpos_diff difference_type;  // "om_termposcount"
        typedef Xapian::termpos * pointer;
        typedef Xapian::termpos & reference;
};

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

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

}

#endif /* XAPIAN_INCLUDED_POSITIONITERATOR_H */

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