backends/flint/flint_cursor.h

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/* bcursor.h: Interface to Btree cursors
 *
 * Copyright 1999,2000,2001 BrightStation PLC
 * Copyright 2002,2003,2004,2006,2007,2010 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_FLINT_CURSOR_H
#define OM_HGUARD_FLINT_CURSOR_H

#include <xapian/visibility.h>

#include "flint_types.h"

#include <string>
using std::string;

#define BLK_UNUSED uint4(-1)

class Cursor_ {
    private:
        // Prevent copying
        Cursor_(const Cursor_ &);
        Cursor_ & operator=(const Cursor_ &);

    public:
        Cursor_() : p(0), c(-1), n(BLK_UNUSED), rewrite(false)
        {}

        byte * p;
        int c;
        uint4 n;
        bool rewrite;
};

class FlintTable;

class XAPIAN_VISIBILITY_DEFAULT FlintCursor {
    private:
        FlintCursor(const FlintCursor &);

        FlintCursor & operator=(const FlintCursor &);

        void rebuild();

        bool is_positioned;

        bool is_after_end;

        enum { UNREAD, UNCOMPRESSED, COMPRESSED } tag_status;

        FlintTable * B;

        Cursor_ * C;

        unsigned long version;

        int level;

        void get_key(string * key) const;

    public:
        FlintCursor(FlintTable *B);

        ~FlintCursor();

        string current_key;

        string current_tag;

        bool read_tag(bool keep_compressed = false);

        bool next();
 
        bool prev();

        bool find_entry(const string &key);

        void find_entry_lt(const string &key) {
            if (find_entry(key)) prev();
        }

        bool find_entry_ge(const string &key);

        void to_end() { is_after_end = true; }

        bool after_end() const { return is_after_end; }

        bool del();

        FlintTable * get_table() const { return B; }
};

#endif /* OM_HGUARD_FLINT_CURSOR_H */

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