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https://git.rwth-aachen.de/acs/public/villas/node/
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70 lines
2.3 KiB
C++
70 lines
2.3 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 <post@steffenvogel.de>
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* @copyright 2014-2022, Institute for Automation of Complex Power Systems, EONERC
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* @license Apache 2.0
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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/node/memory.hpp>
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namespace villas {
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namespace node {
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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 CQueue queue; /**< The queue which is used to keep track of free blocks */
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};
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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_type) __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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ssize_t pool_get_many(struct Pool *p, void *blocks[], size_t cnt);
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/** Push \p cnt values which are giving by the array values to the stack. */
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ssize_t pool_put_many(struct Pool *p, void *blocks[], size_t cnt);
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/** Get a free memory block from pool. */
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void * pool_get(struct Pool *p);
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/** Release a memory block back to the pool. */
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int pool_put(struct Pool *p, void *buf);
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} /* namespace node */
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} /* namespace villas */
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