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-rw-r--r--storage/myisammrg/myrg_rprev.c53
1 files changed, 53 insertions, 0 deletions
diff --git a/storage/myisammrg/myrg_rprev.c b/storage/myisammrg/myrg_rprev.c
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--- /dev/null
+++ b/storage/myisammrg/myrg_rprev.c
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+/* Copyright (c) 2000-2003, 2005-2007 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 */
+
+#include "myrg_def.h"
+
+ /*
+ Read previous row with the same key as previous read
+ */
+
+int myrg_rprev(MYRG_INFO *info, uchar *buf, int inx)
+{
+ int err;
+ MI_INFO *mi;
+
+ if (!info->current_table)
+ return (HA_ERR_KEY_NOT_FOUND);
+
+ /* at first, do rprev for the table found before */
+ if ((err=mi_rprev(info->current_table->table,NULL,inx)))
+ {
+ if (err == HA_ERR_END_OF_FILE)
+ {
+ queue_remove_top(&(info->by_key));
+ if (!info->by_key.elements)
+ return HA_ERR_END_OF_FILE;
+ }
+ else
+ return err;
+ }
+ else
+ {
+ /* Found here, adding to queue */
+ queue_top(&(info->by_key))=(uchar *)(info->current_table);
+ queue_replace_top(&(info->by_key));
+ }
+
+ /* now, mymerge's read_prev is as simple as one queue_top */
+ mi=(info->current_table=(MYRG_TABLE *)queue_top(&(info->by_key)))->table;
+ return _myrg_mi_read_record(mi,buf);
+}