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| 1 | /* | ||
| 2 | * Generic buffer queue | ||
| 3 | * Copyright (c) 2012 Nicolas George | ||
| 4 | * | ||
| 5 | * This file is part of FFmpeg. | ||
| 6 | * | ||
| 7 | * FFmpeg is free software; you can redistribute it and/or | ||
| 8 | * modify it under the terms of the GNU Lesser General Public | ||
| 9 | * License as published by the Free Software Foundation; either | ||
| 10 | * version 2.1 of the License, or (at your option) any later version. | ||
| 11 | * | ||
| 12 | * FFmpeg is distributed in the hope that it will be useful, | ||
| 13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | ||
| 14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | ||
| 15 | * Lesser General Public License for more details. | ||
| 16 | * | ||
| 17 | * You should have received a copy of the GNU Lesser General Public | ||
| 18 | * License along with FFmpeg; if not, write to the Free Software | ||
| 19 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | ||
| 20 | */ | ||
| 21 | |||
| 22 | #ifndef AVFILTER_BUFFERQUEUE_H | ||
| 23 | #define AVFILTER_BUFFERQUEUE_H | ||
| 24 | |||
| 25 | /** | ||
| 26 | * FFBufQueue: simple AVFilterBufferRef queue API | ||
| 27 | * | ||
| 28 | * Note: this API is not thread-safe. Concurrent access to the same queue | ||
| 29 | * must be protected by a mutex or any synchronization mechanism. | ||
| 30 | */ | ||
| 31 | |||
| 32 | /** | ||
| 33 | * Maximum size of the queue. | ||
| 34 | * | ||
| 35 | * This value can be overridden by definying it before including this | ||
| 36 | * header. | ||
| 37 | * Powers of 2 are recommended. | ||
| 38 | */ | ||
| 39 | #ifndef FF_BUFQUEUE_SIZE | ||
| 40 | #define FF_BUFQUEUE_SIZE 32 | ||
| 41 | #endif | ||
| 42 | |||
| 43 | #include "avfilter.h" | ||
| 44 | #include "libavutil/avassert.h" | ||
| 45 | |||
| 46 | /** | ||
| 47 | * Structure holding the queue | ||
| 48 | */ | ||
| 49 | struct FFBufQueue { | ||
| 50 | AVFilterBufferRef *queue[FF_BUFQUEUE_SIZE]; | ||
| 51 | unsigned short head; | ||
| 52 | unsigned short available; /**< number of available buffers */ | ||
| 53 | }; | ||
| 54 | |||
| 55 | #define BUCKET(i) queue->queue[(queue->head + (i)) % FF_BUFQUEUE_SIZE] | ||
| 56 | |||
| 57 | /** | ||
| 58 | * Add a buffer to the queue. | ||
| 59 | * | ||
| 60 | * If the queue is already full, then the current last buffer is dropped | ||
| 61 | * (and unrefed) with a warning before adding the new buffer. | ||
| 62 | */ | ||
| 63 | static inline void ff_bufqueue_add(void *log, struct FFBufQueue *queue, | ||
| 64 | AVFilterBufferRef *buf) | ||
| 65 | { | ||
| 66 | if (queue->available == FF_BUFQUEUE_SIZE) { | ||
| 67 | av_log(log, AV_LOG_WARNING, "Buffer queue overflow, dropping.\n"); | ||
| 68 | avfilter_unref_buffer(BUCKET(--queue->available)); | ||
| 69 | } | ||
| 70 | BUCKET(queue->available++) = buf; | ||
| 71 | } | ||
| 72 | |||
| 73 | /** | ||
| 74 | * Get a buffer from the queue without altering it. | ||
| 75 | * | ||
| 76 | * Buffer with index 0 is the first buffer in the queue. | ||
| 77 | * Return NULL if the queue has not enough buffers. | ||
| 78 | */ | ||
| 79 | static inline AVFilterBufferRef *ff_bufqueue_peek(struct FFBufQueue *queue, | ||
| 80 | unsigned index) | ||
| 81 | { | ||
| 82 | return index < queue->available ? BUCKET(index) : NULL; | ||
| 83 | } | ||
| 84 | |||
| 85 | /** | ||
| 86 | * Get the first buffer from the queue and remove it. | ||
| 87 | * | ||
| 88 | * Do not use on an empty queue. | ||
| 89 | */ | ||
| 90 | static inline AVFilterBufferRef *ff_bufqueue_get(struct FFBufQueue *queue) | ||
| 91 | { | ||
| 92 | AVFilterBufferRef *ret = queue->queue[queue->head]; | ||
| 93 | av_assert0(queue->available); | ||
| 94 | queue->available--; | ||
| 95 | queue->queue[queue->head] = NULL; | ||
| 96 | queue->head = (queue->head + 1) % FF_BUFQUEUE_SIZE; | ||
| 97 | return ret; | ||
| 98 | } | ||
| 99 | |||
| 100 | /** | ||
| 101 | * Unref and remove all buffers from the queue. | ||
| 102 | */ | ||
| 103 | static inline void ff_bufqueue_discard_all(struct FFBufQueue *queue) | ||
| 104 | { | ||
| 105 | while (queue->available) | ||
| 106 | avfilter_unref_buffer(ff_bufqueue_get(queue)); | ||
| 107 | } | ||
| 108 | |||
| 109 | #undef BUCKET | ||
| 110 | |||
| 111 | #endif /* AVFILTER_BUFFERQUEUE_H */ | ||