mariadb/sql/sql_limit.h
Oleksandr Byelkin 1ae02f0e0d MDEV-18553: MDEV-16327 pre-requisits part 2: uniform of LIMIT/OFFSET handling
Now both offset and limit are stored and do not chenged during execution
(offset is decreased during processing in versions before 10.5).

(Big part of this changes made by Monty)
2019-10-13 09:40:41 +02:00

66 lines
1.8 KiB
C++

/* Copyright (c) 2019, MariaDB Corporation.
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; version 2 of the License.
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 02110-1335 USA */
#ifndef INCLUDES_MARIADB_SQL_LIMIT_H
#define INCLUDES_MARIADB_SQL_LIMIT_H
/**
LIMIT/OFFSET parameters for execution.
*/
class Select_limit_counters
{
ha_rows select_limit_cnt, offset_limit_cnt;
public:
Select_limit_counters():
select_limit_cnt(0), offset_limit_cnt(0)
{};
void set_limit(ha_rows limit, ha_rows offset)
{
offset_limit_cnt= offset;
select_limit_cnt= limit;
if (select_limit_cnt + offset_limit_cnt >=
select_limit_cnt)
select_limit_cnt+= offset_limit_cnt;
else
select_limit_cnt= HA_POS_ERROR;
}
void set_single_row()
{
offset_limit_cnt= 0;
select_limit_cnt= 1;
}
bool is_unlimited()
{ return select_limit_cnt == HA_POS_ERROR; }
void set_unlimited()
{ select_limit_cnt= HA_POS_ERROR; offset_limit_cnt= 0; }
bool check_offset(ha_rows sent)
{
return sent < offset_limit_cnt;
}
void remove_offset() { offset_limit_cnt= 0; }
ha_rows get_select_limit()
{ return select_limit_cnt; }
ha_rows get_offset_limit()
{ return offset_limit_cnt; }
};
#endif // INCLUDES_MARIADB_SQL_LIMIT_H