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/** @file chert_alltermslist.h
* @brief A termlist containing all terms in a chert database.
*/
/* Copyright (C) 2005,2007,2008,2009,2010,2011 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_CHERT_ALLTERMSLIST_H
#define XAPIAN_INCLUDED_CHERT_ALLTERMSLIST_H
#include "backends/alltermslist.h"
#include "chert_database.h"
#include "chert_postlist.h"
class ChertCursor;
class ChertAllTermsList : public AllTermsList {
/// Copying is not allowed.
ChertAllTermsList(const ChertAllTermsList &);
/// Assignment is not allowed.
void operator=(const ChertAllTermsList &);
/// Keep a reference to our database to stop it being deleted.
Xapian::Internal::intrusive_ptr<const ChertDatabase> database;
/** A cursor which runs through the postlist table reading termnames from
* the keys.
*/
ChertCursor * cursor;
/// The termname at the current position.
std::string current_term;
/// The prefix to restrict the terms to.
std::string prefix;
/** The term frequency of the term at the current position.
*
* If this value is zero, then we haven't read the term frequency or
* collection frequency for the current term yet. We need to call
* read_termfreq_and_collfreq() to read these.
*/
mutable Xapian::doccount termfreq;
/// The collection frequency of the term at the current position.
mutable Xapian::termcount collfreq;
/// Read and cache the term frequency and collection frequency.
void read_termfreq_and_collfreq() const;
public:
ChertAllTermsList(Xapian::Internal::intrusive_ptr<const ChertDatabase> database_,
const std::string & prefix_)
: database(database_), cursor(NULL), prefix(prefix_), termfreq(0) { }
/// Destructor.
~ChertAllTermsList();
/** Returns the current termname.
*
* Either next() or skip_to() must have been called before this
* method can be called.
*/
std::string get_termname() const;
/** Returns the term frequency of the current term.
*
* Either next() or skip_to() must have been called before this
* method can be called.
*/
Xapian::doccount get_termfreq() const;
/** Returns the collection frequency of the current term.
*
* Either next() or skip_to() must have been called before this
* method can be called.
*/
Xapian::termcount get_collection_freq() const;
/// Advance to the next term in the list.
TermList * next();
/// Advance to the first term which is >= tname.
TermList * skip_to(const std::string &tname);
/// True if we're off the end of the list
bool at_end() const;
};
#endif /* XAPIAN_INCLUDED_CHERT_ALLTERMSLIST_H */
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