jv4-decoder

/*

• 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 */