1/* Copyright (c) 2000-2002, 2004-2007 MySQL AB
2 Use is subject to license terms
3
4 This program is free software; you can redistribute it and/or modify
5 it under the terms of the GNU General Public License as published by
6 the Free Software Foundation; version 2 of the License.
7
8 This program is distributed in the hope that it will be useful,
9 but WITHOUT ANY WARRANTY; without even the implied warranty of
10 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 GNU General Public License for more details.
12
13 You should have received a copy of the GNU General Public License
14 along with this program; if not, write to the Free Software
15 Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA */
16
17#include "heapdef.h"
18
19/* Read first record with the current key */
20
21int heap_rfirst(HP_INFO *info, uchar *record, int inx)
22{
23 HP_SHARE *share = info->s;
24 HP_KEYDEF *keyinfo = share->keydef + inx;
25
26 DBUG_ENTER("heap_rfirst");
27 info->lastinx= inx;
28 info->key_version= info->s->key_version;
29
30 if (keyinfo->algorithm == HA_KEY_ALG_BTREE)
31 {
32 uchar *pos;
33
34 if ((pos = tree_search_edge(&keyinfo->rb_tree, info->parents,
35 &info->last_pos, offsetof(TREE_ELEMENT, left))))
36 {
37 memcpy(&pos, pos + (*keyinfo->get_key_length)(keyinfo, pos),
38 sizeof(uchar*));
39 info->current_ptr = pos;
40 memcpy(record, pos, (size_t)share->reclength);
41 /*
42 If we're performing index_first on a table that was taken from
43 table cache, info->lastkey_len is initialized to previous query.
44 Thus we set info->lastkey_len to proper value for subsequent
45 heap_rnext() calls.
46 This is needed for DELETE queries only, otherwise this variable is
47 not used.
48 Note that the same workaround may be needed for heap_rlast(), but
49 for now heap_rlast() is never used for DELETE queries.
50 */
51 info->lastkey_len= 0;
52 info->update = HA_STATE_AKTIV;
53 }
54 else
55 {
56 info->update= HA_STATE_NO_KEY;
57 my_errno = HA_ERR_END_OF_FILE;
58 DBUG_RETURN(my_errno);
59 }
60 DBUG_RETURN(0);
61 }
62 else
63 {
64 /* We can't scan a non existing key value with hash index */
65 my_errno= HA_ERR_WRONG_COMMAND;
66 DBUG_RETURN(my_errno);
67 }
68}
69