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/** @file chert_dbstats.h
* @brief Chert class for database statistics.
*/
/* Copyright (C) 2009 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_DBSTATS_H
#define XAPIAN_INCLUDED_CHERT_DBSTATS_H
#include "chert_types.h"
#include "xapian/types.h"
#include "internaltypes.h"
class ChertPostListTable;
/// Chert class for database statistics.
class ChertDatabaseStats {
/// Don't allow assignment.
void operator=(const ChertDatabaseStats &);
/// Don't allow copying.
ChertDatabaseStats(const ChertDatabaseStats &);
/// The total of the lengths of all documents in the database.
totlen_t total_doclen;
/// Greatest document id ever used in this database.
Xapian::docid last_docid;
/// A lower bound on the smallest document length in this database.
Xapian::termcount doclen_lbound;
/// An upper bound on the greatest document length in this database.
Xapian::termcount doclen_ubound;
/// An upper bound on the greatest wdf in this database.
Xapian::termcount wdf_ubound;
public:
ChertDatabaseStats()
: total_doclen(0), last_docid(0), doclen_lbound(0), doclen_ubound(0),
wdf_ubound(0) { }
totlen_t get_total_doclen() const { return total_doclen; }
Xapian::docid get_last_docid() const { return last_docid; }
Xapian::termcount get_doclength_lower_bound() const {
return doclen_lbound;
}
Xapian::termcount get_doclength_upper_bound() const {
return doclen_ubound;
}
Xapian::termcount get_wdf_upper_bound() const { return wdf_ubound; }
void zero() {
total_doclen = 0;
last_docid = 0;
doclen_lbound = 0;
doclen_ubound = 0;
wdf_ubound = 0;
}
void read(ChertPostListTable & postlist_table);
void set_last_docid(Xapian::docid did) { last_docid = did; }
void add_document(Xapian::termcount doclen) {
if (total_doclen == 0 || (doclen && doclen < doclen_lbound))
doclen_lbound = doclen;
if (doclen > doclen_ubound)
doclen_ubound = doclen;
total_doclen += doclen;
}
void delete_document(Xapian::termcount doclen) {
total_doclen -= doclen;
// If the database no longer contains any postings, we can reset
// doclen_lbound, doclen_ubound and wdf_ubound.
if (total_doclen == 0) {
doclen_lbound = 0;
doclen_ubound = 0;
wdf_ubound = 0;
}
}
void check_wdf(Xapian::termcount wdf) {
if (wdf > wdf_ubound) wdf_ubound = wdf;
}
Xapian::docid get_next_docid() { return ++last_docid; }
void write(ChertPostListTable & postlist_table) const;
};
#endif // XAPIAN_INCLUDED_CHERT_DBSTATS_H
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