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https://github.com/MariaDB/server.git
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111 lines
3.2 KiB
C
111 lines
3.2 KiB
C
/* Copyright (C) 2000 MySQL AB & MySQL Finland AB & TCX DataKonsult 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; either version 2 of the License, or
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(at your option) any later version.
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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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/* functions on blocks; Keys and records are saved in blocks */
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#include "heapdef.h"
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/* Find record according to record-position */
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byte *_hp_find_block(HP_BLOCK *block, ulong pos)
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{
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reg1 int i;
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reg3 HP_PTRS *ptr;
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for (i=block->levels-1, ptr=block->root ; i > 0 ; i--)
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{
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ptr=(HP_PTRS*)ptr->blocks[pos/block->level_info[i].records_under_level];
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pos%=block->level_info[i].records_under_level;
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}
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return (byte*) ptr+ pos*block->recbuffer;
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}
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/* get one new block-of-records. Alloc ptr to block if neaded */
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/* Interrupts are stopped to allow ha_panic in interrupts */
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int _hp_get_new_block(HP_BLOCK *block, ulong *alloc_length)
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{
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reg1 uint i,j;
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HP_PTRS *root;
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for (i=0 ; i < block->levels ; i++)
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if (block->level_info[i].free_ptrs_in_block)
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break;
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*alloc_length=sizeof(HP_PTRS)*i+block->records_in_block* block->recbuffer;
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if (!(root=(HP_PTRS*) my_malloc(*alloc_length,MYF(0))))
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return 1;
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if (i == 0)
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{
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block->levels=1;
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block->root=block->level_info[0].last_blocks=root;
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}
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else
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{
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dont_break(); /* Dont allow SIGHUP or SIGINT */
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if ((uint) i == block->levels)
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{
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block->levels=i+1;
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block->level_info[i].free_ptrs_in_block=HP_PTRS_IN_NOD-1;
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((HP_PTRS**) root)[0]= block->root;
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block->root=block->level_info[i].last_blocks= root++;
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}
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block->level_info[i].last_blocks->
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blocks[HP_PTRS_IN_NOD - block->level_info[i].free_ptrs_in_block--]=
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(byte*) root;
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for (j=i-1 ; j >0 ; j--)
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{
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block->level_info[j].last_blocks= root++;
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block->level_info[j].last_blocks->blocks[0]=(byte*) root;
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block->level_info[j].free_ptrs_in_block=HP_PTRS_IN_NOD-1;
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}
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block->level_info[0].last_blocks= root;
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allow_break(); /* Allow SIGHUP & SIGINT */
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}
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return 0;
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}
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/* free all blocks under level */
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byte *_hp_free_level(HP_BLOCK *block, uint level, HP_PTRS *pos, byte *last_pos)
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{
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int i,max_pos;
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byte *next_ptr;
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if (level == 1)
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next_ptr=(byte*) pos+block->recbuffer;
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else
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{
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max_pos= (block->level_info[level-1].last_blocks == pos) ?
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HP_PTRS_IN_NOD - block->level_info[level-1].free_ptrs_in_block :
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HP_PTRS_IN_NOD;
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next_ptr=(byte*) (pos+1);
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for (i=0 ; i < max_pos ; i++)
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next_ptr=_hp_free_level(block,level-1,
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(HP_PTRS*) pos->blocks[i],next_ptr);
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}
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if ((byte*) pos != last_pos)
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{
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my_free((gptr) pos,MYF(0));
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return last_pos;
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}
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return next_ptr; /* next memory position */
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}
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