/*
  * Filters implementation helper functions
  *
  * 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_FILTERS_H
 #define AVFILTER_FILTERS_H
 
 /**
  * Filters implementation helper functions
  */
 
 #include "avfilter.h"

 #include "internal.h"

 
 /**

  * Special return code when activate() did not do anything.
  */
 #define FFERROR_NOT_READY FFERRTAG('N','R','D','Y')
 
 /**

  * Mark a filter ready and schedule it for activation.
  *
  * This is automatically done when something happens to the filter (queued
  * frame, status change, request on output).
  * Filters implementing the activate callback can call it directly to
  * perform one more round of processing later.
  * It is also useful for filters reacting to external or asynchronous
  * events.
  */
 void ff_filter_set_ready(AVFilterContext *filter, unsigned priority);
 
 /**

  * Process the commands queued in the link up to the time of the frame.
  * Commands will trigger the process_command() callback.
  * @return  >= 0 or AVERROR code.
  */
 int ff_inlink_process_commands(AVFilterLink *link, const AVFrame *frame);
 
 /**

  * Evaluate the timeline expression of the link for the time and properties
  * of the frame.
  * @return  >0 if enabled, 0 if disabled
  * @note  It does not update link->dst->is_disabled.
  */
 int ff_inlink_evaluate_timeline_at_frame(AVFilterLink *link, const AVFrame *frame);
 
 /**

  * Test if a frame is available on the link.
  * @return  >0 if a frame is available
  */
 int ff_inlink_check_available_frame(AVFilterLink *link);
 
 /**
  * Test if enough samples are available on the link.
  * @return  >0 if enough samples are available
  * @note  on EOF and error, min becomes 1
  */
 int ff_inlink_check_available_samples(AVFilterLink *link, unsigned min);
 
 /**
  * Take a frame from the link's FIFO and update the link's stats.
  *
  * If ff_inlink_check_available_frame() was previously called, the
  * preferred way of expressing it is "av_assert1(ret);" immediately after
  * ff_inlink_consume_frame(). Negative error codes must still be checked.
  *
  * @note  May trigger process_command() and/or update is_disabled.
  * @return  >0 if a frame is available,
  *          0 and set rframe to NULL if no frame available,
  *          or AVERROR code
  */
 int ff_inlink_consume_frame(AVFilterLink *link, AVFrame **rframe);
 
 /**
  * Take samples from the link's FIFO and update the link's stats.
  *
  * If ff_inlink_check_available_samples() was previously called, the
  * preferred way of expressing it is "av_assert1(ret);" immediately after
  * ff_inlink_consume_samples(). Negative error codes must still be checked.
  *
  * @note  May trigger process_command() and/or update is_disabled.
  * @return  >0 if a frame is available,
  *          0 and set rframe to NULL if no frame available,
  *          or AVERROR code
  */
 int ff_inlink_consume_samples(AVFilterLink *link, unsigned min, unsigned max,
                             AVFrame **rframe);
 
 /**

  * Make sure a frame is writable.
  * This is similar to av_frame_make_writable() except it uses the link's
  * buffer allocation callback, and therefore allows direct rendering.
  */
 int ff_inlink_make_frame_writable(AVFilterLink *link, AVFrame **rframe);
 
 /**

  * Test and acknowledge the change of status on the link.
  *
  * Status means EOF or an error condition; a change from the normal (0)
  * status to a non-zero status can be queued in a filter's input link, it
  * becomes relevant after the frames queued in the link's FIFO are
  * processed. This function tests if frames are still queued and if a queued
  * status change has not yet been processed. In that case it performs basic
  * treatment (updating the link's timestamp) and returns a positive value to
  * let the filter do its own treatments (flushing...).
  *
  * Filters implementing the activate callback should call this function when
  * they think it might succeed (usually after checking unsuccessfully for a
  * queued frame).
  * Filters implementing the filter_frame and request_frame callbacks do not
  * need to call that since the same treatment happens in ff_filter_frame().
  *
  * @param[out] rstatus  new or current status
  * @param[out] rpts     current timestamp of the link in link time base
  * @return  >0 if status changed, <0 if status already acked, 0 otherwise
  */
 int ff_inlink_acknowledge_status(AVFilterLink *link, int *rstatus, int64_t *rpts);
 

 /**
  * Mark that a frame is wanted on the link.
  * Unlike ff_filter_frame(), it must not be called when the link has a
  * non-zero status, and thus does not acknowledge it.
  * Also it cannot fail.
  */
 void ff_inlink_request_frame(AVFilterLink *link);
 

 /**

  * Set the status on an input link.
  * Also discard all frames in the link's FIFO.
  */
 void ff_inlink_set_status(AVFilterLink *link, int status);
 
 /**

  * Test if a frame is wanted on an output link.
  */
 static inline int ff_outlink_frame_wanted(AVFilterLink *link)
 {
     return link->frame_wanted_out;
 }
 
 /**

  * Get the status on an output link.
  */
 int ff_outlink_get_status(AVFilterLink *link);
 
 /**

  * Set the status field of a link from the source filter.
  * The pts should reflect the timestamp of the status change,
  * in link time base and relative to the frames timeline.
  * In particular, for AVERROR_EOF, it should reflect the
  * end time of the last frame.
  */
 static inline void ff_outlink_set_status(AVFilterLink *link, int status, int64_t pts)
 {
     ff_avfilter_link_set_in_status(link, status, pts);
 }
 

 /**
  * Forward the status on an output link to an input link.
  * If the status is set, it will discard all queued frames and this macro
  * will return immediately.
  */
 #define FF_FILTER_FORWARD_STATUS_BACK(outlink, inlink) do { \
     int ret = ff_outlink_get_status(outlink); \
     if (ret) { \
         ff_inlink_set_status(inlink, ret); \
         return 0; \
     } \
 } while (0)
 
 /**
  * Forward the status on an output link to all input links.
  * If the status is set, it will discard all queued frames and this macro
  * will return immediately.
  */
 #define FF_FILTER_FORWARD_STATUS_BACK_ALL(outlink, filter) do { \
     int ret = ff_outlink_get_status(outlink); \
     if (ret) { \
         unsigned i; \
         for (i = 0; i < filter->nb_inputs; i++) \
             ff_inlink_set_status(filter->inputs[i], ret); \
         return 0; \
     } \
 } while (0)
 
 /**
  * Acknowledge the status on an input link and forward it to an output link.
  * If the status is set, this macro will return immediately.
  */
 #define FF_FILTER_FORWARD_STATUS(inlink, outlink) do { \
     int status; \
     int64_t pts; \
     if (ff_inlink_acknowledge_status(inlink, &status, &pts)) { \
         ff_outlink_set_status(outlink, status, pts); \
         return 0; \
     } \
 } while (0)
 
 /**
  * Acknowledge the status on an input link and forward it to an output link.
  * If the status is set, this macro will return immediately.
  */
 #define FF_FILTER_FORWARD_STATUS_ALL(inlink, filter) do { \
     int status; \
     int64_t pts; \
     if (ff_inlink_acknowledge_status(inlink, &status, &pts)) { \
         unsigned i; \
         for (i = 0; i < filter->nb_outputs; i++) \
             ff_outlink_set_status(filter->outputs[i], status, pts); \
         return 0; \
     } \
 } while (0)
 
 /**
  * Forward the frame_wanted_out flag from an output link to an input link.
  * If the flag is set, this macro will return immediately.
  */
 #define FF_FILTER_FORWARD_WANTED(outlink, inlink) do { \
     if (ff_outlink_frame_wanted(outlink)) { \
         ff_inlink_request_frame(inlink); \
         return 0; \
     } \
 } while (0)
 

 #endif /* AVFILTER_FILTERS_H */