dep/include/mysql/my_alloc.h

   1 /* Copyright (C) 2000 MySQL AB
   2
   3    This program is free software; you can redistribute it and/or modify
   4    it under the terms of the GNU General Public License as published by
   5    the Free Software Foundation; version 2 of the License.
   6
   7    This program is distributed in the hope that it will be useful,
   8    but WITHOUT ANY WARRANTY; without even the implied warranty of
   9    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  10    GNU General Public License for more details.
  11
  12    You should have received a copy of the GNU General Public License
  13    along with this program; if not, write to the Free Software
  14    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA */
  15
  16 /*
  17    Data structures for mysys/my_alloc.c (root memory allocator)
  18 */
  19
  20 #ifndef _my_alloc_h
  21 #define _my_alloc_h
  22
  23 #define ALLOC_MAX_BLOCK_TO_DROP                 4096
  24 #define ALLOC_MAX_BLOCK_USAGE_BEFORE_DROP       10
  25
  26 typedef struct st_used_mem
  27 {                                  /* struct for once_alloc (block) */
  28   struct st_used_mem *next;        /* Next block in use */
  29   unsigned int  left;              /* memory left in block  */
  30   unsigned int  size;              /* size of block */
  31 } USED_MEM;
  32
  33
  34 typedef struct st_mem_root
  35 {
  36   USED_MEM *free;                  /* blocks with free memory in it */
  37   USED_MEM *used;                  /* blocks almost without free memory */
  38   USED_MEM *pre_alloc;             /* preallocated block */
  39   /* if block have less memory it will be put in 'used' list */
  40   unsigned int min_malloc;
  41   unsigned int block_size;         /* initial block size */
  42   unsigned int block_num;          /* allocated blocks counter */
  43   /*
  44      first free block in queue test counter (if it exceed
  45      MAX_BLOCK_USAGE_BEFORE_DROP block will be dropped in 'used' list)
  46   */
  47   unsigned int first_block_usage;
  48
  49   void (*error_handler)(void);
  50 } MEM_ROOT;
  51 #endif