mirror of
https://github.com/FFmpeg/FFmpeg.git
synced 2024-12-12 19:18:44 +02:00
120 lines
3.3 KiB
C
120 lines
3.3 KiB
C
/*
|
|
* Generic buffer queue
|
|
* Copyright (c) 2012 Nicolas George
|
|
*
|
|
* This file is part of FFmpeg.
|
|
*
|
|
* FFmpeg is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU Lesser General Public
|
|
* License as published by the Free Software Foundation; either
|
|
* version 2.1 of the License, or (at your option) any later version.
|
|
*
|
|
* FFmpeg 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
|
|
* Lesser General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU Lesser General Public
|
|
* License along with FFmpeg; if not, write to the Free Software
|
|
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
|
|
*/
|
|
|
|
#ifndef AVFILTER_BUFFERQUEUE_H
|
|
#define AVFILTER_BUFFERQUEUE_H
|
|
|
|
/**
|
|
* FFBufQueue: simple AVFilterBufferRef queue API
|
|
*
|
|
* Note: this API is not thread-safe. Concurrent access to the same queue
|
|
* must be protected by a mutex or any synchronization mechanism.
|
|
*/
|
|
|
|
/**
|
|
* Maximum size of the queue.
|
|
*
|
|
* This value can be overridden by definying it before including this
|
|
* header.
|
|
* Powers of 2 are recommended.
|
|
*/
|
|
#ifndef FF_BUFQUEUE_SIZE
|
|
#define FF_BUFQUEUE_SIZE 32
|
|
#endif
|
|
|
|
#include "avfilter.h"
|
|
#include "libavutil/avassert.h"
|
|
|
|
/**
|
|
* Structure holding the queue
|
|
*/
|
|
struct FFBufQueue {
|
|
AVFilterBufferRef *queue[FF_BUFQUEUE_SIZE];
|
|
unsigned short head;
|
|
unsigned short available; /**< number of available buffers */
|
|
};
|
|
|
|
#define BUCKET(i) queue->queue[(queue->head + (i)) % FF_BUFQUEUE_SIZE]
|
|
|
|
/**
|
|
* Test if a buffer queue is full.
|
|
*/
|
|
static inline int ff_bufqueue_is_full(struct FFBufQueue *queue)
|
|
{
|
|
return queue->available == FF_BUFQUEUE_SIZE;
|
|
}
|
|
|
|
/**
|
|
* Add a buffer to the queue.
|
|
*
|
|
* If the queue is already full, then the current last buffer is dropped
|
|
* (and unrefed) with a warning before adding the new buffer.
|
|
*/
|
|
static inline void ff_bufqueue_add(void *log, struct FFBufQueue *queue,
|
|
AVFilterBufferRef *buf)
|
|
{
|
|
if (ff_bufqueue_is_full(queue)) {
|
|
av_log(log, AV_LOG_WARNING, "Buffer queue overflow, dropping.\n");
|
|
avfilter_unref_buffer(BUCKET(--queue->available));
|
|
}
|
|
BUCKET(queue->available++) = buf;
|
|
}
|
|
|
|
/**
|
|
* Get a buffer from the queue without altering it.
|
|
*
|
|
* Buffer with index 0 is the first buffer in the queue.
|
|
* Return NULL if the queue has not enough buffers.
|
|
*/
|
|
static inline AVFilterBufferRef *ff_bufqueue_peek(struct FFBufQueue *queue,
|
|
unsigned index)
|
|
{
|
|
return index < queue->available ? BUCKET(index) : NULL;
|
|
}
|
|
|
|
/**
|
|
* Get the first buffer from the queue and remove it.
|
|
*
|
|
* Do not use on an empty queue.
|
|
*/
|
|
static inline AVFilterBufferRef *ff_bufqueue_get(struct FFBufQueue *queue)
|
|
{
|
|
AVFilterBufferRef *ret = queue->queue[queue->head];
|
|
av_assert0(queue->available);
|
|
queue->available--;
|
|
queue->queue[queue->head] = NULL;
|
|
queue->head = (queue->head + 1) % FF_BUFQUEUE_SIZE;
|
|
return ret;
|
|
}
|
|
|
|
/**
|
|
* Unref and remove all buffers from the queue.
|
|
*/
|
|
static inline void ff_bufqueue_discard_all(struct FFBufQueue *queue)
|
|
{
|
|
while (queue->available)
|
|
avfilter_unref_buffer(ff_bufqueue_get(queue));
|
|
}
|
|
|
|
#undef BUCKET
|
|
|
|
#endif /* AVFILTER_BUFFERQUEUE_H */
|