1 files changed, 53 insertions, 0 deletions
diff --git a/storage/myisammrg/myrg_rprev.c b/storage/myisammrg/myrg_rprev.c
new file mode 100644
index 00000000000..797993e903d
--- /dev/null
+++ b/storage/myisammrg/myrg_rprev.c
@@ -0,0 +1,53 @@
+/* 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 */
+
+#include "myrg_def.h"
+
+	/*
+	   Read previous row with the same key as previous read
+	*/
+
+int myrg_rprev(MYRG_INFO *info, byte *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(&(info->by_key),0);
+      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))=(byte *)(info->current_table);
+    queue_replaced(&(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);
+}