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/* Copyright (C) 2000-2002 MySQL AB
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; version 2 of the License.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
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#include "heap_priv.h"
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using namespace drizzled;
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/* Read next record with the same key */
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int heap_rnext(HP_INFO *info, unsigned char *record)
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HP_SHARE *share=info->s;
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if (info->lastinx < 0)
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return(errno=HA_ERR_WRONG_INDEX);
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keyinfo = share->keydef + info->lastinx;
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if (keyinfo->algorithm == HA_KEY_ALG_BTREE)
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heap_rb_param custom_arg;
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We enter this branch for non-DELETE queries after heap_rkey()
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or heap_rfirst(). As last key position (info->last_pos) is available,
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we only need to climb the tree using tree_search_next().
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pos = (unsigned char *)tree_search_next(&keyinfo->rb_tree,
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offsetof(TREE_ELEMENT, left),
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offsetof(TREE_ELEMENT, right));
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else if (!info->lastkey_len)
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We enter this branch only for DELETE queries after heap_rfirst(). E.g.
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DELETE FROM t1 WHERE a<10. As last key position is not available
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(last key is removed by heap_delete()), we must restart search as it
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is done in heap_rfirst().
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It should be safe to handle this situation without this branch. That is
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branch below should find smallest element in a tree as lastkey_len is
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zero. tree_search_edge() is a kind of optimisation here as it should be
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faster than tree_search_key().
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pos= (unsigned char *)tree_search_edge(&keyinfo->rb_tree, info->parents,
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offsetof(TREE_ELEMENT, left));
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We enter this branch only for DELETE queries after heap_rkey(). E.g.
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DELETE FROM t1 WHERE a=10. As last key position is not available
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(last key is removed by heap_delete()), we must restart search as it
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is done in heap_rkey().
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custom_arg.keyseg = keyinfo->seg;
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custom_arg.key_length = info->lastkey_len;
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custom_arg.search_flag = SEARCH_SAME | SEARCH_FIND;
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pos = (unsigned char *)tree_search_key(&keyinfo->rb_tree,
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info->lastkey, info->parents,
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memcpy(&pos, pos + (*keyinfo->get_key_length)(keyinfo, pos),
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sizeof(unsigned char*));
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info->current_ptr = pos;
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errno = HA_ERR_KEY_NOT_FOUND;
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if (info->current_hash_ptr)
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pos= hp_search_next(info, keyinfo, info->lastkey,
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info->current_hash_ptr);
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if (!info->current_ptr && (info->update & HA_STATE_NEXT_FOUND))
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pos=0; /* Read next after last */
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errno=HA_ERR_KEY_NOT_FOUND;
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else if (!info->current_ptr) /* Deleted or first call */
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pos= hp_search(info, keyinfo, info->lastkey, 0);
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pos= hp_search(info, keyinfo, info->lastkey, 1);
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info->update=HA_STATE_NEXT_FOUND; /* For heap_rprev */
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if (errno == HA_ERR_KEY_NOT_FOUND)
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errno=HA_ERR_END_OF_FILE;
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hp_extract_record(share, record, pos);
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info->update=HA_STATE_AKTIV | HA_STATE_NEXT_FOUND;