1/*
2Copyright (c) 2012, Broadcom Europe Ltd
3All rights reserved.
4
5Redistribution and use in source and binary forms, with or without
6modification, are permitted provided that the following conditions are met:
7 * Redistributions of source code must retain the above copyright
8 notice, this list of conditions and the following disclaimer.
9 * Redistributions in binary form must reproduce the above copyright
10 notice, this list of conditions and the following disclaimer in the
11 documentation and/or other materials provided with the distribution.
12 * Neither the name of the copyright holder nor the
13 names of its contributors may be used to endorse or promote products
14 derived from this software without specific prior written permission.
15
16THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
17ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
18WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
19DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY
20DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
21(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
22LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
23ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
24(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
25SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26*/
27
28#ifndef MMAL_QUEUE_H
29#define MMAL_QUEUE_H
30
31#ifdef __cplusplus
32extern "C" {
33#endif
34
35/** \defgroup MmalQueue Queues of buffer headers
36 * This provides a thread-safe implementation of a queue of buffer headers
37 * (\ref MMAL_BUFFER_HEADER_T). The queue works in a first-in, first-out basis
38 * so the buffer headers will be dequeued in the order they have been queued. */
39/* @{ */
40
41#include "mmal_buffer.h"
42
43typedef struct MMAL_QUEUE_T MMAL_QUEUE_T;
44
45/** Create a queue of MMAL_BUFFER_HEADER_T
46 *
47 * @return Pointer to the newly created queue or NULL on failure.
48 */
49MMAL_QUEUE_T *mmal_queue_create(void);
50
51/** Put a MMAL_BUFFER_HEADER_T into a queue
52 *
53 * @param queue Pointer to a queue
54 * @param buffer Pointer to the MMAL_BUFFER_HEADER_T to add to the queue
55 */
56void mmal_queue_put(MMAL_QUEUE_T *queue, MMAL_BUFFER_HEADER_T *buffer);
57
58/** Put a MMAL_BUFFER_HEADER_T back at the start of a queue.
59 * This is used when a buffer header was removed from the queue but not
60 * fully processed and needs to be put back where it was originally taken.
61 *
62 * @param queue Pointer to a queue
63 * @param buffer Pointer to the MMAL_BUFFER_HEADER_T to add to the queue
64 */
65void mmal_queue_put_back(MMAL_QUEUE_T *queue, MMAL_BUFFER_HEADER_T *buffer);
66
67/** Get a MMAL_BUFFER_HEADER_T from a queue
68 *
69 * @param queue Pointer to a queue
70 *
71 * @return pointer to the next MMAL_BUFFER_HEADER_T or NULL if the queue is empty.
72 */
73MMAL_BUFFER_HEADER_T *mmal_queue_get(MMAL_QUEUE_T *queue);
74
75/** Wait for a MMAL_BUFFER_HEADER_T from a queue.
76 * This is the same as a get except that this will block until a buffer header is
77 * available.
78 *
79 * @param queue Pointer to a queue
80 *
81 * @return pointer to the next MMAL_BUFFER_HEADER_T.
82 */
83MMAL_BUFFER_HEADER_T *mmal_queue_wait(MMAL_QUEUE_T *queue);
84
85/** Wait for a MMAL_BUFFER_HEADER_T from a queue, up to a given timeout.
86 * This is the same as a wait, except that it will abort in case of timeout.
87 *
88 * @param queue Pointer to a queue
89 * @param timeout Number of milliseconds to wait before
90 * returning if the semaphore can't be acquired.
91 *
92 * @return pointer to the next MMAL_BUFFER_HEADER_T.
93 */
94MMAL_BUFFER_HEADER_T *mmal_queue_timedwait(MMAL_QUEUE_T *queue, VCOS_UNSIGNED timeout);
95
96/** Get the number of MMAL_BUFFER_HEADER_T currently in a queue.
97 *
98 * @param queue Pointer to a queue
99 *
100 * @return length (in elements) of the queue.
101 */
102unsigned int mmal_queue_length(MMAL_QUEUE_T *queue);
103
104/** Destroy a queue of MMAL_BUFFER_HEADER_T.
105 *
106 * @param queue Pointer to a queue
107 */
108void mmal_queue_destroy(MMAL_QUEUE_T *queue);
109
110/* @} */
111
112#ifdef __cplusplus
113}
114#endif
115
116#endif /* MMAL_QUEUE_H */
117