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82 lines
No EOL
2.2 KiB
C
82 lines
No EOL
2.2 KiB
C
/** Lock-less LIFO stack
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*
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* Based on a single-linked list and double word compare exchange (DWCAS)
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* to solve the ABA problem.
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*
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* Based on https://github.com/skeeto/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 2014-2016, Institute for Automation of Complex Power Systems, EONERC
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* This file is part of S2SS. All Rights Reserved. Proprietary and confidential.
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* Unauthorized copying of this file, via any medium is strictly prohibited.
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*********************************************************************************/
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#ifndef _LSTACK_H_
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#define _LSTACK_H_
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#include <stdlib.h>
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#include <stdint.h>
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#include <stdatomic.h>
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struct lstack_node {
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void *value;
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struct lstack_node *next;
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};
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/** DWCAS cmpexch16 */
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struct lstack_head {
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uintptr_t aba;
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struct lstack_node *node;
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};
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struct lstack {
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struct lstack_node *node_buffer;
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_Atomic struct lstack_head head, free;
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_Atomic size_t size, avail;
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};
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/** Initialize a lock-less stack which can hold up to maxsz values.
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*
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* Note: this function is not thread-safe.
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*/
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int lstack_init(struct lstack *lstack, size_t maxsz);
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/** Pop cnt values from the stack an place them in the array values */
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ssize_t lstack_pop_many(struct lstack *lstack, void *values[], size_t cnt);
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/** Push cnt values which are giving by the array values to the stack. */
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ssize_t lstack_push_many(struct lstack *lstack, void *values[], size_t cnt);
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/** Push a single value to the stack. */
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static inline __attribute__((unused)) int lstack_push(struct lstack *lstack, void *value)
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{
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return lstack_push_many(lstack, &value, 1) == 1 ? 0 : -1;
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}
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/** Pop a single element from the stack and return it. */
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static inline __attribute__((unused)) void * lstack_pop(struct lstack *lstack)
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{
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void *value;
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lstack_pop_many(lstack, &value, 1);
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return value;
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}
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/** Return the approximate size of the stack. */
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static inline __attribute__((unused)) size_t lstack_size(struct lstack *lstack)
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{
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return atomic_load(&lstack->size);
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}
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/** Release memory used by the stack.
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*
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* Note: this function is not thread-safe.
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*/
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static inline __attribute__((unused)) void lstack_destroy(struct lstack *lstack)
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{
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free(lstack->node_buffer);
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}
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#endif /* _LSTACK_H_ */ |