/*
* 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_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_send(AVThreadMessageQueue *mq,
int err);

/**
* Set the receiving 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_recv(AVThreadMessageQueue *mq,
int err);

#endif /* AVUTIL_THREADMESSAGE_H */