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- /* Copyright (c) 2000, 2021, Oracle and/or its affiliates.
-
- This program is free software; you can redistribute it and/or modify
- it under the terms of the GNU General Public License, version 2.0,
- as published by the Free Software Foundation.
-
- This program is also distributed with certain software (including
- but not limited to OpenSSL) that is licensed under separate terms,
- as designated in a particular file or component or in included license
- documentation. The authors of MySQL hereby grant you an additional
- permission to link the program and your derivative works with the
- separately licensed software that they have included with MySQL.
-
- 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, version 2.0, 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 02110-1301, 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)
- {
- set_my_errno(HA_ERR_WRONG_INDEX);
- DBUG_RETURN(HA_ERR_WRONG_INDEX);
- }
-
- keyinfo = share->keydef + info->lastinx;
- if (keyinfo->algorithm == HA_KEY_ALG_BTREE)
- {
- heap_rb_param custom_arg;
-
- 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;
- 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
- {
- set_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 */
- set_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)
- set_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);
- }
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