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