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-rw-r--r--storage/myisam/mi_rrnd.c60
1 files changed, 60 insertions, 0 deletions
diff --git a/storage/myisam/mi_rrnd.c b/storage/myisam/mi_rrnd.c
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+++ b/storage/myisam/mi_rrnd.c
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+/* Copyright (c) 2000-2002, 2004-2007 MySQL AB
+ Use is subject to license terms
+
+ 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 Street, Fifth Floor, Boston, MA 02110-1335 USA */
+
+/* Read a record with random-access. The position to the record must
+ get by MI_INFO. The next record can be read with pos= MI_POS_ERROR */
+
+
+#include "myisamdef.h"
+
+/*
+ Read a row based on position.
+ If filepos= HA_OFFSET_ERROR then read next row
+ Return values
+ Returns one of following values:
+ 0 = Ok.
+ HA_ERR_RECORD_DELETED = Record is deleted.
+ HA_ERR_END_OF_FILE = EOF.
+*/
+
+int mi_rrnd(MI_INFO *info, uchar *buf, register my_off_t filepos)
+{
+ my_bool skip_deleted_blocks;
+ DBUG_ENTER("mi_rrnd");
+
+ skip_deleted_blocks=0;
+
+ if (filepos == HA_OFFSET_ERROR)
+ {
+ skip_deleted_blocks=1;
+ if (info->lastpos == HA_OFFSET_ERROR) /* First read ? */
+ filepos= info->s->pack.header_length; /* Read first record */
+ else
+ filepos= info->nextpos;
+ }
+
+ if (info->once_flags & RRND_PRESERVE_LASTINX)
+ info->once_flags&= ~RRND_PRESERVE_LASTINX;
+ else
+ 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,skip_deleted_blocks));
+}