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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 */
/* functions on blocks; Keys and records are saved in blocks */
#include "heapdef.h"
/* Find record according to record-position */
byte *_hp_find_block(HP_BLOCK *block, ulong pos)
{
reg1 int i;
reg3 HP_PTRS *ptr;
for (i=block->levels-1, ptr=block->root ; i > 0 ; i--)
{
ptr=(HP_PTRS*)ptr->blocks[pos/block->level_info[i].records_under_level];
pos%=block->level_info[i].records_under_level;
}
return (byte*) ptr+ pos*block->recbuffer;
}
/* get one new block-of-records. Alloc ptr to block if neaded */
/* Interrupts are stopped to allow ha_panic in interrupts */
int _hp_get_new_block(HP_BLOCK *block, ulong *alloc_length)
{
reg1 uint i,j;
HP_PTRS *root;
for (i=0 ; i < block->levels ; i++)
if (block->level_info[i].free_ptrs_in_block)
break;
*alloc_length=sizeof(HP_PTRS)*i+block->records_in_block* block->recbuffer;
if (!(root=(HP_PTRS*) my_malloc(*alloc_length,MYF(0))))
return 1;
if (i == 0)
{
block->levels=1;
block->root=block->level_info[0].last_blocks=root;
}
else
{
dont_break(); /* Dont allow SIGHUP or SIGINT */
if ((uint) i == block->levels)
{
block->levels=i+1;
block->level_info[i].free_ptrs_in_block=HP_PTRS_IN_NOD-1;
((HP_PTRS**) root)[0]= block->root;
block->root=block->level_info[i].last_blocks= root++;
}
block->level_info[i].last_blocks->
blocks[HP_PTRS_IN_NOD - block->level_info[i].free_ptrs_in_block--]=
(byte*) root;
for (j=i-1 ; j >0 ; j--)
{
block->level_info[j].last_blocks= root++;
block->level_info[j].last_blocks->blocks[0]=(byte*) root;
block->level_info[j].free_ptrs_in_block=HP_PTRS_IN_NOD-1;
}
block->level_info[0].last_blocks= root;
allow_break(); /* Allow SIGHUP & SIGINT */
}
return 0;
}
/* free all blocks under level */
byte *_hp_free_level(HP_BLOCK *block, uint level, HP_PTRS *pos, byte *last_pos)
{
int i,max_pos;
byte *next_ptr;
if (level == 1)
next_ptr=(byte*) pos+block->recbuffer;
else
{
max_pos= (block->level_info[level-1].last_blocks == pos) ?
HP_PTRS_IN_NOD - block->level_info[level-1].free_ptrs_in_block :
HP_PTRS_IN_NOD;
next_ptr=(byte*) (pos+1);
for (i=0 ; i < max_pos ; i++)
next_ptr=_hp_free_level(block,level-1,
(HP_PTRS*) pos->blocks[i],next_ptr);
}
if ((byte*) pos != last_pos)
{
my_free((gptr) pos,MYF(0));
return last_pos;
}
return next_ptr; /* next memory position */
}
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