rrnd.c
上传用户:romrleung
上传日期:2022-05-23
资源大小:18897k
文件大小:2k
- /* Copyright (C) 2000 MySQL AB & MySQL Finland AB & TCX DataKonsult AB
- 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
- /* Read a record with random-access. The position to the record must
- get by N_INFO. The next record can be read with pos= -1 */
- #include "isamdef.h"
- /*
- If filepos == NI_POS_ERROR, read next
- Returns:
- 0 = Ok.
- 1 = Row was deleted
- -1 = EOF (check errno to verify)
- */
- int nisam_rrnd(N_INFO *info, byte *buf, register ulong filepos)
- {
- int skipp_deleted_blocks;
- DBUG_ENTER("nisam_rrnd");
- skipp_deleted_blocks=0;
- if (filepos == NI_POS_ERROR)
- {
- skipp_deleted_blocks=1;
- if (info->lastpos == NI_POS_ERROR) /* First read ? */
- filepos= info->s->pack.header_length; /* Read first record */
- else
- filepos= info->nextpos;
- }
- info->lastinx= -1; /* Can't forward or backward */
- /* Init all but update-flag */
- info->update&= (HA_STATE_CHANGED | HA_STATE_ROW_CHANGED);
- if (info->opt_flag & WRITE_CACHE_USED && flush_io_cache(&info->rec_cache))
- DBUG_RETURN(my_errno);
- DBUG_RETURN ((*info->s->read_rnd)(info,buf,filepos,skipp_deleted_blocks));
- }