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/* Copyright (C) 2000 MySQL AB & Ramil Kalimullin
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 "myisamdef.h"
#include "rt_index.h"
#include "rt_key.h"
#include "rt_mbr.h"
/*
Add key to the page
RESULT VALUES
-1 Error
0 Not split
1 Split
*/
int rtree_add_key(MI_INFO *info, MI_KEYDEF *keyinfo, uchar *key,
uint key_length, uchar *page_buf, my_off_t *new_page)
{
uint page_size = mi_getint(page_buf);
uint nod_flag = mi_test_if_nod(page_buf);
if (page_size + key_length + nod_flag <= keyinfo->block_length)
{
/* split won't be necessary */
if (nod_flag)
{
/* save key */
memcpy(rt_PAGE_END(page_buf), key - nod_flag, key_length + nod_flag);
page_size += key_length + nod_flag;
}
else
{
/* save key */
memcpy(rt_PAGE_END(page_buf), key, key_length +
info->s->base.rec_reflength);
page_size += key_length + info->s->base.rec_reflength;
}
mi_putint(page_buf, page_size, nod_flag);
return 0;
}
return (rtree_split_page(info, keyinfo, page_buf, key, key_length,
new_page) ? -1 : 1);
}
/*
Delete key from the page
*/
int rtree_delete_key(MI_INFO *info, uchar *page_buf, uchar *key,
uint key_length, uint nod_flag)
{
uint16 page_size = mi_getint(page_buf);
uchar *key_start;
key_start= key - nod_flag;
if (!nod_flag)
key_length += info->s->base.rec_reflength;
memmove(key_start, key + key_length, page_size - key_length -
(key - page_buf));
page_size-= key_length + nod_flag;
mi_putint(page_buf, page_size, nod_flag);
return 0;
}
/*
Calculate and store key MBR
*/
int rtree_set_key_mbr(MI_INFO *info, MI_KEYDEF *keyinfo, uchar *key,
uint key_length, my_off_t child_page)
{
if (!_mi_fetch_keypage(info, keyinfo, child_page,
DFLT_INIT_HITS, info->buff, 0))
return -1;
return rtree_page_mbr(info, keyinfo->seg, info->buff, key, key_length);
}
/*
Choose non-leaf better key for insertion
*/
uchar *rtree_choose_key(MI_INFO *info, MI_KEYDEF *keyinfo, uchar *key,
uint key_length, uchar *page_buf, uint nod_flag)
{
double increase;
double best_incr = DBL_MAX;
double area;
double best_area;
uchar *best_key;
uchar *k = rt_PAGE_FIRST_KEY(page_buf, nod_flag);
uchar *last = rt_PAGE_END(page_buf);
LINT_INIT(best_area);
LINT_INIT(best_key);
for (; k < last; k = rt_PAGE_NEXT_KEY(k, key_length, nod_flag))
{
if ((increase = rtree_area_increase(keyinfo->seg, key, k, key_length,
&area)) == -1)
return NULL;
if (increase < best_incr)
{
best_key = k;
best_area = area;
best_incr = increase;
}
else
{
if ((increase == best_incr) && (area < best_area))
{
best_key = k;
best_area = area;
best_incr = increase;
}
}
}
return best_key;
}
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