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https://git.rwth-aachen.de/acs/public/villas/node/
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93 lines
3.2 KiB
C
93 lines
3.2 KiB
C
/** Memory pool for fixed size objects.
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*
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* This datastructure is based on a lock-less stack (lstack).
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*
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* @file
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* @author Steffen Vogel <stvogel@eonerc.rwth-aachen.de>
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* @copyright 2014-2020, Institute for Automation of Complex Power Systems, EONERC
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* @license GNU General Public License (version 3)
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*
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* VILLASnode
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*********************************************************************************/
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#pragma once
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#include <cstddef>
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#include <sys/types.h>
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#include <villas/queue.h>
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#include <villas/common.hpp>
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#include <villas/memory.h>
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/** A thread-safe memory pool */
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struct pool {
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enum State state;
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off_t buffer_off; /**< Offset from the struct address to the underlying memory area */
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size_t len; /**< Length of the underlying memory area */
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size_t blocksz; /**< Length of a block in bytes */
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size_t alignment; /**< Alignment of a block in bytes */
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struct queue queue; /**< The queue which is used to keep track of free blocks */
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};
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#define INLINE static inline __attribute__((unused))
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#define pool_buffer(p) ((char *) (p) + (p)->buffer_off)
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/** Initiazlize a pool
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*
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* @param[inout] p The pool data structure.
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* @param[in] cnt The total number of blocks which are reserverd by this pool.
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* @param[in] blocksz The size in bytes per block.
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* @param[in] mem The type of memory which should be used for this pool.
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* @retval 0 The pool has been successfully initialized.
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* @retval <>0 There was an error during the pool initialization.
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*/
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int pool_init(struct pool *p, size_t cnt, size_t blocksz, struct memory_type *mem = memory_default) __attribute__ ((warn_unused_result));
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/** Destroy and release memory used by pool. */
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int pool_destroy(struct pool *p) __attribute__ ((warn_unused_result));
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/** Pop up to \p cnt values from the stack an place them in the array \p blocks.
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*
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* @return The number of blocks actually retrieved from the pool.
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* This number can be smaller than the requested \p cnt blocks
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* in case the pool currently holds less than \p cnt blocks.
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*/
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INLINE ssize_t pool_get_many(struct pool *p, void *blocks[], size_t cnt)
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{
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return queue_pull_many(&p->queue, blocks, cnt);
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}
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/** Push \p cnt values which are giving by the array values to the stack. */
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INLINE ssize_t pool_put_many(struct pool *p, void *blocks[], size_t cnt)
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{
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return queue_push_many(&p->queue, blocks, cnt);
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}
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/** Get a free memory block from pool. */
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INLINE void * pool_get(struct pool *p)
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{
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void *ptr;
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return queue_pull(&p->queue, &ptr) == 1 ? ptr : nullptr;
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}
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/** Release a memory block back to the pool. */
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INLINE int pool_put(struct pool *p, void *buf)
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{
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return queue_push(&p->queue, buf);
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}
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