LGPL-ize wfqueue
[urcu.git] / urcu / wfqueue.h
1 #ifndef _URCU_WFQUEUE_H
2 #define _URCU_WFQUEUE_H
3
4 /*
5 * wfqueue.h
6 *
7 * Userspace RCU library - Queue with Wait-Free Enqueue/Blocking Dequeue
8 *
9 * Copyright 2010 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
10 *
11 * This library is free software; you can redistribute it and/or
12 * modify it under the terms of the GNU Lesser General Public
13 * License as published by the Free Software Foundation; either
14 * version 2.1 of the License, or (at your option) any later version.
15 *
16 * This library is distributed in the hope that it will be useful,
17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
19 * Lesser General Public License for more details.
20 *
21 * You should have received a copy of the GNU Lesser General Public
22 * License along with this library; if not, write to the Free Software
23 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
24 */
25
26 #include <pthread.h>
27 #include <assert.h>
28 #include <urcu/compiler.h>
29
30 #ifdef __cplusplus
31 extern "C" {
32 #endif
33
34 /*
35 * Queue with wait-free enqueue/blocking dequeue.
36 * This implementation adds a dummy head node when the queue is empty to ensure
37 * we can always update the queue locklessly.
38 *
39 * Inspired from half-wait-free/half-blocking queue implementation done by
40 * Paul E. McKenney.
41 */
42
43 struct wfq_node {
44 struct wfq_node *next;
45 };
46
47 struct wfq_queue {
48 struct wfq_node *head, **tail;
49 struct wfq_node dummy; /* Dummy node */
50 pthread_mutex_t lock;
51 };
52
53 #ifdef _LGPL_SOURCE
54
55 #include <urcu/wfqueue-static.h>
56
57 #define wfq_node_init _wfq_node_init
58 #define wfq_init _wfq_init
59 #define wfq_enqueue _wfq_enqueue
60 #define wfq_dequeue_blocking _wfq_dequeue_blocking
61
62 #else /* !_LGPL_SOURCE */
63
64 extern void wfq_node_init(struct wfq_node *node);
65 extern void wfq_init(struct wfq_queue *q);
66 extern void wfq_enqueue(struct wfq_queue *q, struct wfq_node *node);
67 extern struct wfq_node *wfq_dequeue_blocking(struct wfq_queue *q);
68
69 #endif /* !_LGPL_SOURCE */
70
71 #ifdef __cplusplus
72 }
73 #endif
74
75 #endif /* _URCU_WFQUEUE_H */
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