postingiterator.h

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/* Copyright (C) 2007,2008,2009,2010,2011,2012,2013,2014,2015 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

#if !defined XAPIAN_IN_XAPIAN_H && !defined XAPIAN_LIB_BUILD
# error Never use <xapian/postingiterator.h> directly; include <xapian.h> instead.
#endif

#include <iterator>
#include <string>

#include <xapian/attributes.h>
#include <xapian/derefwrapper.h>
#include <xapian/positioniterator.h>
#include <xapian/types.h>
#include <xapian/visibility.h>

namespace Xapian {

class XAPIAN_VISIBILITY_DEFAULT PostingIterator {
  public:
    class Internal;
    Internal * internal;

    explicit PostingIterator(Internal *internal_);

    PostingIterator(const PostingIterator & o);

    PostingIterator & operator=(const PostingIterator & o);

#ifdef XAPIAN_MOVE_SEMANTICS
    PostingIterator(PostingIterator && o)
        : internal(o.internal) {
        o.internal = nullptr;
    }

    PostingIterator & operator=(PostingIterator && o) {
        if (this != &o) {
            if (internal) decref();
            internal = o.internal;
            o.internal = nullptr;
        }
        return *this;
    }
#endif

    XAPIAN_NOTHROW(PostingIterator())
        : internal() { }

    ~PostingIterator() {
        if (internal) decref();
    }

    Xapian::docid operator*() const;

    Xapian::termcount get_wdf() const;

    Xapian::termcount get_doclength() const;

    Xapian::termcount get_unique_terms() const;

#if 0 // FIXME: TermIterator supports this, so PostingIterator really ought to.
    Xapian::termcount positionlist_count() const;
#endif

    PositionIterator positionlist_begin() const;

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

    PostingIterator & operator++();

    DerefWrapper_<Xapian::docid> operator++(int) {
        Xapian::docid did(**this);
        operator++();
        return DerefWrapper_<Xapian::docid>(did);
    }

    void skip_to(Xapian::docid did);

    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;
    // @}

  private:
    void decref();

    void post_advance(Internal * res);
};

bool
XAPIAN_NOTHROW(operator==(const PostingIterator &a, const PostingIterator &b));

inline bool
operator==(const PostingIterator &a, const PostingIterator &b) XAPIAN_NOEXCEPT
{
    // Use a pointer comparison - this ensures both that (a == a) and correct
    // handling of end iterators (which we ensure have NULL internals).
    return a.internal == b.internal;
}

inline bool
XAPIAN_NOTHROW(operator!=(const PostingIterator &a, const PostingIterator &b));

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

}

#endif // XAPIAN_INCLUDED_POSTINGITERATOR_H