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/*
* This program 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 2
* of the License, or (at your option) any later version.
*
* 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 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, Fifth Floor, Boston, MA 02110-1301, USA.
*
* The Original Code is Copyright (C) 2018 Blender Foundation.
* All rights reserved.
*/
/** \file \ingroup bli
*/
#include "MEM_guardedalloc.h"
#include "BLI_linklist_lockfree.h"
#include "BLI_strict_flags.h"
#include "atomic_ops.h"
void BLI_linklist_lockfree_init(LockfreeLinkList *list)
{
list->dummy_node.next = NULL;
list->head = list->tail = &list->dummy_node;
}
void BLI_linklist_lockfree_free(LockfreeLinkList *list,
LockfreeeLinkNodeFreeFP free_func)
{
if (free_func != NULL) {
/* NOTE: We start from a first user-added node. */
LockfreeLinkNode *node = list->head->next;
while (node != NULL) {
LockfreeLinkNode *node_next = node->next;
free_func(node);
node = node_next;
}
}
}
void BLI_linklist_lockfree_clear(LockfreeLinkList *list,
LockfreeeLinkNodeFreeFP free_func)
{
BLI_linklist_lockfree_free(list, free_func);
BLI_linklist_lockfree_init(list);
}
void BLI_linklist_lockfree_insert(LockfreeLinkList *list,
LockfreeLinkNode *node)
{
/* Based on:
*
* John D. Valois
* Implementing Lock-Free Queues
*
* http://people.csail.mit.edu/bushl2/rpi/portfolio/lockfree-grape/documents/lock-free-linked-lists.pdf
*/
bool keep_working;
LockfreeLinkNode *tail_node;
node->next = NULL;
do {
tail_node = list->tail;
keep_working =
(atomic_cas_ptr((void **)&tail_node->next, NULL, node) != NULL);
if (keep_working) {
atomic_cas_ptr((void **)&list->tail, tail_node, tail_node->next);
}
} while (keep_working);
atomic_cas_ptr((void **)&list->tail, tail_node, node);
}
LockfreeLinkNode *BLI_linklist_lockfree_begin(LockfreeLinkList *list)
{
return list->head->next;
}
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