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/* Copyright (C) 2000 MySQL AB & MySQL Finland AB & TCX DataKonsult AB
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 */
/* remove current record in heap-database */
#include "heapdef.h"
int heap_delete(HP_INFO *info, const byte *record)
{
uint key;
byte *pos;
HP_SHARE *share=info->s;
DBUG_ENTER("heap_delete");
DBUG_PRINT("enter",("info: %lx record: %lx",info,record));
test_active(info);
if (info->opt_flag & READ_CHECK_USED && _hp_rectest(info,record))
DBUG_RETURN(my_errno); /* Record changed */
share->changed=1;
if ( --(share->records) < share->blength >> 1) share->blength>>=1;
pos=info->current_ptr;
for (key=0 ; key < share->keys ; key++)
{
if (_hp_delete_key(info,share->keydef+key,record,pos,
key == (uint) info->lastinx))
goto err;
}
info->update=HA_STATE_DELETED;
*((byte**) pos)=share->del_link;
share->del_link=pos;
pos[share->reclength]=0; /* Record deleted */
share->deleted++;
info->current_hash_ptr=0;
DBUG_RETURN(0);
err:
if( ++(share->records) == share->blength) share->blength+= share->blength;
DBUG_RETURN(my_errno);
}
/* Remove one key from hash-table */
/* Flag is set if we want's to correct info->current_ptr */
int _hp_delete_key(HP_INFO *info, register HP_KEYDEF *keyinfo,
const byte *record, byte *recpos, int flag)
{
ulong blength,pos2,pos_hashnr,lastpos_hashnr;
HASH_INFO *lastpos,*gpos,*pos,*pos3,*empty,*last_ptr;
HP_SHARE *share=info->s;
DBUG_ENTER("_hp_delete_key");
blength=share->blength;
if (share->records+1 == blength) blength+= blength;
lastpos=hp_find_hash(&keyinfo->block,share->records);
last_ptr=0;
/* Search after record with key */
pos= hp_find_hash(&keyinfo->block,
_hp_mask(_hp_rec_hashnr(keyinfo,record),blength,
share->records+1));
gpos = pos3 = 0;
while (pos->ptr_to_rec != recpos)
{
if (flag && !_hp_rec_key_cmp(keyinfo,record,pos->ptr_to_rec))
last_ptr=pos; /* Previous same key */
gpos=pos;
if (!(pos=pos->next_key))
{
DBUG_RETURN(my_errno=HA_ERR_CRASHED); /* This shouldn't happend */
}
}
/* Remove link to record */
if (flag)
{
/* Save for heap_rnext/heap_rprev */
info->current_hash_ptr=last_ptr;
info->current_ptr = last_ptr ? last_ptr->ptr_to_rec : 0;
DBUG_PRINT("info",("Corrected current_ptr to point at: %lx",
info->current_ptr));
}
empty=pos;
if (gpos)
gpos->next_key=pos->next_key; /* unlink current ptr */
else if (pos->next_key)
{
empty=pos->next_key;
pos->ptr_to_rec=empty->ptr_to_rec;
pos->next_key=empty->next_key;
}
if (empty == lastpos) /* deleted last hash key */
DBUG_RETURN (0);
/* Move the last key (lastpos) */
lastpos_hashnr=_hp_rec_hashnr(keyinfo,lastpos->ptr_to_rec);
/* pos is where lastpos should be */
pos=hp_find_hash(&keyinfo->block,_hp_mask(lastpos_hashnr,share->blength,
share->records));
if (pos == empty) /* Move to empty position. */
{
empty[0]=lastpos[0];
DBUG_RETURN(0);
}
pos_hashnr=_hp_rec_hashnr(keyinfo,pos->ptr_to_rec);
/* pos3 is where the pos should be */
pos3= hp_find_hash(&keyinfo->block,
_hp_mask(pos_hashnr,share->blength,share->records));
if (pos != pos3)
{ /* pos is on wrong posit */
empty[0]=pos[0]; /* Save it here */
pos[0]=lastpos[0]; /* This shold be here */
_hp_movelink(pos,pos3,empty); /* Fix link to pos */
DBUG_RETURN(0);
}
pos2= _hp_mask(lastpos_hashnr,blength,share->records+1);
if (pos2 == _hp_mask(pos_hashnr,blength,share->records+1))
{ /* Identical key-positions */
if (pos2 != share->records)
{
empty[0]=lastpos[0];
_hp_movelink(lastpos,pos,empty);
DBUG_RETURN(0);
}
pos3= pos; /* Link pos->next after lastpos */
}
else pos3= 0; /* Different positions merge */
empty[0]=lastpos[0];
_hp_movelink(pos3,empty,pos->next_key);
pos->next_key=empty;
DBUG_RETURN(0);
}
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