maptermlist.h

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/* Copyright 1999,2000,2001 BrightStation PLC
 * Copyright 2002,2003,2004,2005,2006,2007,2008,2010,2011,2013 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 OM_HGUARD_MAPTERMLIST_H
#define OM_HGUARD_MAPTERMLIST_H

#include "termlist.h"

#include "backends/inmemory/inmemory_positionlist.h"
#include "backends/document.h"

#include "omassert.h"

using namespace std;

class MapTermList : public TermList {
    private:
        Xapian::Document::Internal::document_terms::const_iterator it;
        Xapian::Document::Internal::document_terms::const_iterator it_end;
        bool started;

    public:
        MapTermList(const Xapian::Document::Internal::document_terms::const_iterator &it_,
                    const Xapian::Document::Internal::document_terms::const_iterator &it_end_)
                : it(it_), it_end(it_end_), started(false)
        { }

        // Gets size of termlist
        Xapian::termcount get_approx_size() const {
            // This method shouldn't get called on a MapTermList.
            Assert(false);
            return 0;
        }

        // Gets current termname
        string get_termname() const {
            Assert(started);
            Assert(!at_end());
            return it->first;
        }

        // Get wdf of current term
        Xapian::termcount get_wdf() const {
            Assert(started);
            Assert(!at_end());
            return it->second.wdf;
        }

        // Get num of docs indexed by term
        Xapian::doccount get_termfreq() const {
            throw Xapian::InvalidOperationError("Can't get term frequency from a document termlist which is not associated with a database.");
        }

        const std::vector<Xapian::termpos> * get_vector_termpos() const {
            return it->second.get_vector_termpos();
        }

        Xapian::PositionIterator positionlist_begin() const {
            auto p = it->second.get_vector_termpos();
            return Xapian::PositionIterator(new InMemoryPositionList(*p));
        }

        Xapian::termcount positionlist_count() const {
            return it->second.positionlist_count();
        }

        TermList * next() {
            if (!started) {
                started = true;
            } else {
                Assert(!at_end());
                ++it;
            }
            while (it != it_end && it->second.is_deleted()) {
                ++it;
            }
            return NULL;
        }

        TermList * skip_to(const std::string & term) {
            while (it != it_end && it->first < term) {
                ++it;
            }
            started = true;
            while (it != it_end && it->second.is_deleted()) {
                ++it;
            }
            return NULL;
        }

        // True if we're off the end of the list
        bool at_end() const {
            Assert(started);
            return it == it_end;
        }
};

#endif /* OM_HGUARD_MAPTERMLIST_H */