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-rw-r--r--storage/heap/hp_rnext.c130
1 files changed, 130 insertions, 0 deletions
diff --git a/storage/heap/hp_rnext.c b/storage/heap/hp_rnext.c
new file mode 100644
index 00000000..f227ce4d
--- /dev/null
+++ b/storage/heap/hp_rnext.c
@@ -0,0 +1,130 @@
+/* Copyright (c) 2000, 2002, 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 "heapdef.h"
+
+/* Read next record with the same key */
+
+int heap_rnext(HP_INFO *info, uchar *record)
+{
+ uchar *pos;
+ HP_SHARE *share=info->s;
+ HP_KEYDEF *keyinfo;
+ DBUG_ENTER("heap_rnext");
+
+ if (info->lastinx < 0)
+ DBUG_RETURN(my_errno=HA_ERR_WRONG_INDEX);
+
+ keyinfo = share->keydef + info->lastinx;
+ if (keyinfo->algorithm == HA_KEY_ALG_BTREE)
+ {
+ heap_rb_param custom_arg;
+
+ /* If no active record and last was not deleted */
+ if (!(info->update & (HA_STATE_AKTIV | HA_STATE_NO_KEY |
+ HA_STATE_DELETED)))
+ {
+ if (info->update & HA_STATE_NEXT_FOUND)
+ pos= 0; /* Can't search after last row */
+ else
+ {
+ /* Last was 'prev' before first record; search after first record */
+ pos= tree_search_edge(&keyinfo->rb_tree, info->parents,
+ &info->last_pos, offsetof(TREE_ELEMENT, left));
+ }
+ }
+ else if (info->last_pos)
+ {
+ /*
+ We enter this branch for non-DELETE queries after heap_rkey()
+ or heap_rfirst(). As last key position (info->last_pos) is available,
+ we only need to climb the tree using tree_search_next().
+ */
+ pos = tree_search_next(&keyinfo->rb_tree, &info->last_pos,
+ offsetof(TREE_ELEMENT, left),
+ offsetof(TREE_ELEMENT, right));
+ }
+ else if (!info->lastkey_len)
+ {
+ /*
+ We enter this branch only for DELETE queries after heap_rfirst(). E.g.
+ DELETE FROM t1 WHERE a<10. As last key position is not available
+ (last key is removed by heap_delete()), we must restart search as it
+ is done in heap_rfirst().
+
+ It should be safe to handle this situation without this branch. That is
+ branch below should find smallest element in a tree as lastkey_len is
+ zero. tree_search_edge() is a kind of optimisation here as it should be
+ faster than tree_search_key().
+ */
+ pos= tree_search_edge(&keyinfo->rb_tree, info->parents,
+ &info->last_pos, offsetof(TREE_ELEMENT, left));
+ }
+ else
+ {
+ /*
+ We enter this branch only for DELETE queries after heap_rkey(). E.g.
+ DELETE FROM t1 WHERE a=10. As last key position is not available
+ (last key is removed by heap_delete()), we must restart search as it
+ is done in heap_rkey().
+ */
+ custom_arg.keyseg = keyinfo->seg;
+ custom_arg.key_length = info->lastkey_len;
+ custom_arg.search_flag = SEARCH_SAME | SEARCH_FIND;
+ info->last_find_flag= HA_READ_KEY_OR_NEXT;
+ pos = tree_search_key(&keyinfo->rb_tree, info->lastkey, info->parents,
+ &info->last_pos, info->last_find_flag, &custom_arg);
+ }
+ if (pos)
+ {
+ memcpy(&pos, pos + (*keyinfo->get_key_length)(keyinfo, pos),
+ sizeof(uchar*));
+ info->current_ptr = pos;
+ }
+ else
+ {
+ my_errno = HA_ERR_KEY_NOT_FOUND;
+ }
+ }
+ else
+ {
+ if (info->current_hash_ptr)
+ pos= hp_search_next(info, keyinfo, info->lastkey,
+ info->current_hash_ptr);
+ else
+ {
+ if (!info->current_ptr && (info->update & HA_STATE_NEXT_FOUND))
+ {
+ pos=0; /* Read next after last */
+ my_errno=HA_ERR_KEY_NOT_FOUND;
+ }
+ else if (!info->current_ptr) /* Deleted or first call */
+ pos= hp_search(info, keyinfo, info->lastkey, 0);
+ else
+ pos= hp_search(info, keyinfo, info->lastkey, 1);
+ }
+ }
+ if (!pos)
+ {
+ info->update=HA_STATE_NEXT_FOUND; /* For heap_rprev */
+ if (my_errno == HA_ERR_KEY_NOT_FOUND)
+ my_errno=HA_ERR_END_OF_FILE;
+ DBUG_RETURN(my_errno);
+ }
+ memcpy(record,pos,(size_t) share->reclength);
+ info->update=HA_STATE_AKTIV | HA_STATE_NEXT_FOUND;
+ DBUG_RETURN(0);
+}