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/*
ChibiOS - Copyright (C) 2006..2015 Giovanni Di Sirio.
This file is part of ChibiOS.
ChibiOS 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 3 of the License, or
(at your option) any later version.
ChibiOS 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, see <http://www.gnu.org/licenses/>.
*/
/**
* @file chmempools.c
* @brief Memory Pools code.
*
* @addtogroup pools
* @details Memory Pools related APIs and services.
* <h2>Operation mode</h2>
* The Memory Pools APIs allow to allocate/free fixed size objects in
* <b>constant time</b> and reliably without memory fragmentation
* problems.<br>
* Memory Pools do not enforce any alignment constraint on the
* contained object however the objects must be properly aligned
* to contain a pointer to void.
* @pre In order to use the memory pools APIs the @p CH_CFG_USE_MEMPOOLS option
* must be enabled in @p chconf.h.
* @{
*/
#include "ch.h"
#if CH_CFG_USE_MEMPOOLS || defined(__DOXYGEN__)
/*===========================================================================*/
/* Module exported variables. */
/*===========================================================================*/
/*===========================================================================*/
/* Module local types. */
/*===========================================================================*/
/*===========================================================================*/
/* Module local variables. */
/*===========================================================================*/
/*===========================================================================*/
/* Module local functions. */
/*===========================================================================*/
/*===========================================================================*/
/* Module exported functions. */
/*===========================================================================*/
/**
* @brief Initializes an empty memory pool.
*
* @param[out] mp pointer to a @p memory_pool_t structure
* @param[in] size the size of the objects contained in this memory pool,
* the minimum accepted size is the size of a pointer to
* void.
* @param[in] provider memory provider function for the memory pool or
* @p NULL if the pool is not allowed to grow
* automatically
*
* @init
*/
void chPoolObjectInit(memory_pool_t *mp, size_t size, memgetfunc_t provider) {
chDbgCheck((mp != NULL) && (size >= sizeof(void *)));
mp->mp_next = NULL;
mp->mp_object_size = size;
mp->mp_provider = provider;
}
/**
* @brief Loads a memory pool with an array of static objects.
* @pre The memory pool must be already been initialized.
* @pre The array elements must be of the right size for the specified
* memory pool.
* @post The memory pool contains the elements of the input array.
*
* @param[in] mp pointer to a @p memory_pool_t structure
* @param[in] p pointer to the array first element
* @param[in] n number of elements in the array
*
* @api
*/
void chPoolLoadArray(memory_pool_t *mp, void *p, size_t n) {
chDbgCheck((mp != NULL) && (n != 0));
while (n) {
chPoolAdd(mp, p);
p = (void *)(((uint8_t *)p) + mp->mp_object_size);
n--;
}
}
/**
* @brief Allocates an object from a memory pool.
* @pre The memory pool must be already been initialized.
*
* @param[in] mp pointer to a @p memory_pool_t structure
* @return The pointer to the allocated object.
* @retval NULL if pool is empty.
*
* @iclass
*/
void *chPoolAllocI(memory_pool_t *mp) {
void *objp;
chDbgCheckClassI();
chDbgCheck(mp != NULL);
if ((objp = mp->mp_next) != NULL) {
mp->mp_next = mp->mp_next->ph_next;
}
else if (mp->mp_provider != NULL) {
objp = mp->mp_provider(mp->mp_object_size);
}
return objp;
}
/**
* @brief Allocates an object from a memory pool.
* @pre The memory pool must be already been initialized.
*
* @param[in] mp pointer to a @p memory_pool_t structure
* @return The pointer to the allocated object.
* @retval NULL if pool is empty.
*
* @api
*/
void *chPoolAlloc(memory_pool_t *mp) {
void *objp;
chSysLock();
objp = chPoolAllocI(mp);
chSysUnlock();
return objp;
}
/**
* @brief Releases an object into a memory pool.
* @pre The memory pool must be already been initialized.
* @pre The freed object must be of the right size for the specified
* memory pool.
* @pre The object must be properly aligned to contain a pointer to void.
*
* @param[in] mp pointer to a @p memory_pool_t structure
* @param[in] objp the pointer to the object to be released
*
* @iclass
*/
void chPoolFreeI(memory_pool_t *mp, void *objp) {
struct pool_header *php = objp;
chDbgCheckClassI();
chDbgCheck((mp != NULL) && (objp != NULL));
php->ph_next = mp->mp_next;
mp->mp_next = php;
}
/**
* @brief Releases an object into a memory pool.
* @pre The memory pool must be already been initialized.
* @pre The freed object must be of the right size for the specified
* memory pool.
* @pre The object must be properly aligned to contain a pointer to void.
*
* @param[in] mp pointer to a @p memory_pool_t structure
* @param[in] objp the pointer to the object to be released
*
* @api
*/
void chPoolFree(memory_pool_t *mp, void *objp) {
chSysLock();
chPoolFreeI(mp, objp);
chSysUnlock();
}
#endif /* CH_CFG_USE_MEMPOOLS */
/** @} */
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