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FFmpeg/fftools/thread_queue.h
Anton Khirnov 37c764df67 fftools: add a multistream thread-safe queue
It is similar to AVThreadMessageQueue, but supports multiple streams,
each with its own EOF state.
2022-07-23 11:53:19 +02:00

82 lines
3.1 KiB
C

/*
* 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 FFTOOLS_THREAD_QUEUE_H
#define FFTOOLS_THREAD_QUEUE_H
#include <string.h>
#include "objpool.h"
typedef struct ThreadQueue ThreadQueue;
/**
* Allocate a queue for sending data between threads.
*
* @param nb_streams number of streams for which a distinct EOF state is
* maintained
* @param queue_size number of items that can be stored in the queue without
* blocking
* @param obj_pool object pool that will be used to allocate items stored in the
* queue; the pool becomes owned by the queue
* @param callback that moves the contents between two data pointers
*/
ThreadQueue *tq_alloc(unsigned int nb_streams, size_t queue_size,
ObjPool *obj_pool, void (*obj_move)(void *dst, void *src));
void tq_free(ThreadQueue **tq);
/**
* Send an item for the given stream to the queue.
*
* @param data the item to send, its contents will be moved using the callback
* provided to tq_alloc(); on failure the item will be left
* untouched
* @return
* - 0 the item was successfully sent
* - AVERROR(ENOMEM) could not allocate an item for writing to the FIFO
* - AVERROR(EINVAL) the sending side has previously been marked as finished
* - AVERROR_EOF the receiving side has marked the given stream as finished
*/
int tq_send(ThreadQueue *tq, unsigned int stream_idx, void *data);
/**
* Mark the given stream finished from the sending side.
*/
void tq_send_finish(ThreadQueue *tq, unsigned int stream_idx);
/**
* Read the next item from the queue.
*
* @param stream_idx the index of the stream that was processed or -1 will be
* written here
* @param data the data item will be written here on success using the
* callback provided to tq_alloc()
* @return
* - 0 a data item was successfully read; *stream_idx contains a non-negative
* stream index
* - AVERROR_EOF When *stream_idx is non-negative, this signals that the sending
* side has marked the given stream as finished. This will happen at most once
* for each stream. When *stream_idx is -1, all streams are done.
*/
int tq_receive(ThreadQueue *tq, int *stream_idx, void *data);
/**
* Mark the given stream finished from the receiving side.
*/
void tq_receive_finish(ThreadQueue *tq, unsigned int stream_idx);
#endif // FFTOOLS_THREAD_QUEUE_H