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Diffstat (limited to '')
-rw-r--r-- | sql/sql_limit.h | 72 |
1 files changed, 72 insertions, 0 deletions
diff --git a/sql/sql_limit.h b/sql/sql_limit.h new file mode 100644 index 00000000..a4fcedac --- /dev/null +++ b/sql/sql_limit.h @@ -0,0 +1,72 @@ +/* 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) + {}; + Select_limit_counters(Select_limit_counters &orig): + select_limit_cnt(orig.select_limit_cnt), + offset_limit_cnt(orig.offset_limit_cnt) + {}; + + 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; } + bool is_unrestricted() + { return select_limit_cnt == HA_POS_ERROR && offset_limit_cnt == 0; } + 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 |