~drizzle-trunk/drizzle/development

/* 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; version 2 of the License.

   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 */

  size_t min_malloc;

  size_t 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