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/*
* 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 AVUTIL_THREADMESSAGE_H
#define AVUTIL_THREADMESSAGE_H
typedef struct AVThreadMessageQueue AVThreadMessageQueue;
typedef enum AVThreadMessageFlags {
/**
* Perform non-blocking operation.
* If this flag is set, send and recv operations are non-blocking and
* return AVERROR(EAGAIN) immediately if they can not proceed.
*/
AV_THREAD_MESSAGE_NONBLOCK = 1,
} AVThreadMessageFlags;
/**
* Allocate a new message queue.
*
* @param mq pointer to the message queue
* @param nelem maximum number of elements in the queue
* @param elsize size of each element in the queue
* @return >=0 for success; <0 for error, in particular AVERROR(ENOSYS) if
* lavu was built without thread support
*/
int av_thread_message_queue_alloc(AVThreadMessageQueue **mq,
unsigned nelem,
unsigned elsize);
/**
* Free a message queue.
*
* The message queue must no longer be in use by another thread.
*/
void av_thread_message_queue_free(AVThreadMessageQueue **mq);
/**
* Send a message on the queue.
*/
int av_thread_message_queue_send(AVThreadMessageQueue *mq,
void *msg,
unsigned flags);
/**
* Receive a message from the queue.
*/
int av_thread_message_queue_recv(AVThreadMessageQueue *mq,
void *msg,
unsigned flags);
/**
* Set the sending error code.
*
* If the error code is set to non-zero, av_thread_message_queue_send() will
* return it immediately. Conventional values, such as AVERROR_EOF or
* AVERROR(EAGAIN), can be used to cause the sending thread to stop or
* suspend its operation.
*/
void av_thread_message_queue_set_err_send(AVThreadMessageQueue *mq,
int err);
/**
* Set the receiving error code.
*
* If the error code is set to non-zero, av_thread_message_queue_recv() will
* return it immediately when there are no longer available messages.
* Conventional values, such as AVERROR_EOF or AVERROR(EAGAIN), can be used
* to cause the receiving thread to stop or suspend its operation.
*/
void av_thread_message_queue_set_err_recv(AVThreadMessageQueue *mq,
int err);
/**
* Set the optional free message callback function which will be called if an
* operation is removing messages from the queue.
*/
void av_thread_message_queue_set_free_func(AVThreadMessageQueue *mq,
void (*free_func)(void *msg));
/**
* Return the current number of messages in the queue.
*
* @return the current number of messages or AVERROR(ENOSYS) if lavu was built
* without thread support
*/
int av_thread_message_queue_nb_elems(AVThreadMessageQueue *mq);
/**
* Flush the message queue
*
* This function is mostly equivalent to reading and free-ing every message
* except that it will be done in a single operation (no lock/unlock between
* reads).
*/
void av_thread_message_flush(AVThreadMessageQueue *mq);
#endif /* AVUTIL_THREADMESSAGE_H */
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