my_alloc.h
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上传日期:2022-05-23
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- /* Copyright (C) 2000 MySQL 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 */
- /*
- Data structures for mysys/my_alloc.c (root memory allocator)
- */
- #ifndef _my_alloc_h
- #define _my_alloc_h
- #define ALLOC_MAX_BLOCK_TO_DROP 4096
- #define ALLOC_MAX_BLOCK_USAGE_BEFORE_DROP 10
- typedef struct st_used_mem
- { /* struct for once_alloc (block) */
- struct st_used_mem *next; /* Next block in use */
- unsigned int left; /* memory left in block */
- unsigned int size; /* size of block */
- } USED_MEM;
- typedef struct st_mem_root
- {
- USED_MEM *free; /* blocks with free memory in it */
- USED_MEM *used; /* blocks almost without free memory */
- USED_MEM *pre_alloc; /* preallocated block */
- /* if block have less memory it will be put in 'used' list */
- unsigned int min_malloc;
- unsigned int block_size; /* initial block size */
- unsigned int block_num; /* allocated blocks counter */
- /*
- first free block in queue test counter (if it exceed
- MAX_BLOCK_USAGE_BEFORE_DROP block will be dropped in 'used' list)
- */
- unsigned int first_block_usage;
- void (*error_handler)(void);
- } MEM_ROOT;
- #endif