/*****************************************************************************

Copyright (c) 1994, 2009, Oracle and/or its affiliates. All Rights Reserved.

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License, version 2.0,
as published by the Free Software Foundation.

This program is also distributed with certain software (including
but not limited to OpenSSL) that is licensed under separate terms,
as designated in a particular file or component or in included license
documentation.  The authors of MySQL hereby grant you an additional
permission to link the program and your derivative works with the
separately licensed software that they have included with MySQL.

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, version 2.0, 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.,
51 Franklin Street, Suite 500, Boston, MA 02110-1335 USA

*****************************************************************************/

/**************************************************//**
@file include/mem0pool.h
The lowest-level memory management

Created 6/9/1994 Heikki Tuuri
*******************************************************/

#ifndef mem0pool_h
#define mem0pool_h

#include "univ.i"
#include "os0file.h"
#include "ut0lst.h"

/** Memory pool */
struct mem_pool_t;

/** The common memory pool */
extern mem_pool_t*	mem_comm_pool;

/** Memory area header */
struct mem_area_t{
	ulint		size_and_free;	/*!< memory area size is obtained by
					anding with ~MEM_AREA_FREE; area in
					a free list if ANDing with
					MEM_AREA_FREE results in nonzero */
	UT_LIST_NODE_T(mem_area_t)
			free_list;	/*!< free list node */
};

/** Each memory area takes this many extra bytes for control information */
#define MEM_AREA_EXTRA_SIZE	(ut_calc_align(sizeof(struct mem_area_t),\
			UNIV_MEM_ALIGNMENT))

/********************************************************************//**
Creates a memory pool.
@return	memory pool */
UNIV_INTERN
mem_pool_t*
mem_pool_create(
/*============*/
	ulint	size);	/*!< in: pool size in bytes */
/********************************************************************//**
Frees a memory pool. */
UNIV_INTERN
void
mem_pool_free(
/*==========*/
	mem_pool_t*	pool);	/*!< in, own: memory pool */
/********************************************************************//**
Allocates memory from a pool. NOTE: This low-level function should only be
used in mem0mem.*!
@return	own: allocated memory buffer */
UNIV_INTERN
void*
mem_area_alloc(
/*===========*/
	ulint*		psize,	/*!< in: requested size in bytes; for optimum
				space usage, the size should be a power of 2
				minus MEM_AREA_EXTRA_SIZE;
				out: allocated size in bytes (greater than
				or equal to the requested size) */
	mem_pool_t*	pool);	/*!< in: memory pool */
/********************************************************************//**
Frees memory to a pool. */
UNIV_INTERN
void
mem_area_free(
/*==========*/
	void*		ptr,	/*!< in, own: pointer to allocated memory
				buffer */
	mem_pool_t*	pool);	/*!< in: memory pool */
/********************************************************************//**
Returns the amount of reserved memory.
@return	reserved mmeory in bytes */
UNIV_INTERN
ulint
mem_pool_get_reserved(
/*==================*/
	mem_pool_t*	pool);	/*!< in: memory pool */
/********************************************************************//**
Validates a memory pool.
@return	TRUE if ok */
UNIV_INTERN
ibool
mem_pool_validate(
/*==============*/
	mem_pool_t*	pool);	/*!< in: memory pool */
/********************************************************************//**
Prints info of a memory pool. */
UNIV_INTERN
void
mem_pool_print_info(
/*================*/
	FILE*		outfile,/*!< in: output file to write to */
	mem_pool_t*	pool);	/*!< in: memory pool */


#ifndef UNIV_NONINL
#include "mem0pool.ic"
#endif

#endif
