/*

  * Copyright (c) 2007 Bobby Bingham

  *
  * 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
  */
 
 /**
  * @file

  * FIFO buffering filter

  */
 

 #include "libavutil/avassert.h"

 #include "libavutil/channel_layout.h"

 #include "libavutil/common.h"

 #include "libavutil/mathematics.h"
 #include "libavutil/samplefmt.h"
 

 #include "audio.h"

 #include "avfilter.h"

 #include "internal.h"

 #include "video.h"

 typedef struct Buf {

     AVFrame *frame;

     struct Buf        *next;
 } Buf;

 typedef struct FifoContext {

     Buf  root;
     Buf *last;   ///< last buffered frame

 
     /**
      * When a specific number of output samples is requested, the partial
      * buffer is stored here
      */

     AVFrame *out;
     int allocated_samples;      ///< number of samples out was allocated for

 } FifoContext;
 

 static av_cold int init(AVFilterContext *ctx)

 {
     FifoContext *fifo = ctx->priv;
     fifo->last = &fifo->root;
 
     return 0;
 }
 
 static av_cold void uninit(AVFilterContext *ctx)
 {
     FifoContext *fifo = ctx->priv;

     Buf *buf, *tmp;

     for (buf = fifo->root.next; buf; buf = tmp) {
         tmp = buf->next;

         av_frame_free(&buf->frame);

         av_free(buf);

     }

     av_frame_free(&fifo->out);

 }
 

 static int add_to_queue(AVFilterLink *inlink, AVFrame *frame)

 {
     FifoContext *fifo = inlink->dst->priv;
 

     fifo->last->next = av_mallocz(sizeof(Buf));

     if (!fifo->last->next) {

         av_frame_free(&frame);

         return AVERROR(ENOMEM);
     }
 

     fifo->last = fifo->last->next;

     fifo->last->frame = frame;

 
     return 0;
 }
 

 static void queue_pop(FifoContext *s)
 {
     Buf *tmp = s->root.next->next;
     if (s->last == s->root.next)
         s->last = &s->root;
     av_freep(&s->root.next);
     s->root.next = tmp;
 }
 
 /**
  * Move data pointers and pts offset samples forward.
  */

 static void buffer_offset(AVFilterLink *link, AVFrame *frame,

                           int offset)
 {

     int nb_channels = link->channels;

     int planar = av_sample_fmt_is_planar(link->format);
     int planes = planar ? nb_channels : 1;
     int block_align = av_get_bytes_per_sample(link->format) * (planar ? 1 : nb_channels);
     int i;
 

     av_assert0(frame->nb_samples > offset);

 
     for (i = 0; i < planes; i++)

         frame->extended_data[i] += block_align * offset;
     if (frame->data != frame->extended_data)
         memcpy(frame->data, frame->extended_data,
                FFMIN(planes, FF_ARRAY_ELEMS(frame->data)) * sizeof(*frame->data));
     frame->linesize[0] -= block_align*offset;
     frame->nb_samples -= offset;
 
     if (frame->pts != AV_NOPTS_VALUE) {
         frame->pts += av_rescale_q(offset, (AVRational){1, link->sample_rate},
                                    link->time_base);

     }
 }
 

 static int calc_ptr_alignment(AVFrame *frame)

 {

     int planes = av_sample_fmt_is_planar(frame->format) ?

                  frame->channels : 1;

     int min_align = 128;
     int p;
 
     for (p = 0; p < planes; p++) {
         int cur_align = 128;

         while ((intptr_t)frame->extended_data[p] % cur_align)

             cur_align >>= 1;
         if (cur_align < min_align)
             min_align = cur_align;
     }
     return min_align;
 }
 
 static int return_audio_frame(AVFilterContext *ctx)
 {
     AVFilterLink *link = ctx->outputs[0];
     FifoContext *s = ctx->priv;

     AVFrame *head = s->root.next ? s->root.next->frame : NULL;

     AVFrame *out;

     int ret;
 

     /* if head is NULL then we're flushing the remaining samples in out */
     if (!head && !s->out)
         return AVERROR_EOF;
 

     if (!s->out &&
         head->nb_samples >= link->request_samples &&

         calc_ptr_alignment(head) >= 32) {

         if (head->nb_samples == link->request_samples) {
             out = head;

             queue_pop(s);
         } else {

             out = av_frame_clone(head);
             if (!out)

                 return AVERROR(ENOMEM);
 

             out->nb_samples = link->request_samples;

             buffer_offset(link, head, link->request_samples);
         }
     } else {

         int nb_channels = link->channels;

         if (!s->out) {
             s->out = ff_get_audio_buffer(link, link->request_samples);
             if (!s->out)

                 return AVERROR(ENOMEM);
 

             s->out->nb_samples = 0;
             s->out->pts                   = head->pts;

             s->allocated_samples          = link->request_samples;
         } else if (link->request_samples != s->allocated_samples) {
             av_log(ctx, AV_LOG_ERROR, "request_samples changed before the "
                    "buffer was returned.\n");
             return AVERROR(EINVAL);
         }
 

         while (s->out->nb_samples < s->allocated_samples) {

             int len;
 
             if (!s->root.next) {
                 ret = ff_request_frame(ctx->inputs[0]);
                 if (ret == AVERROR_EOF) {
                     av_samples_set_silence(s->out->extended_data,
                                            s->out->nb_samples,
                                            s->allocated_samples -
                                            s->out->nb_samples,
                                            nb_channels, link->format);
                     s->out->nb_samples = s->allocated_samples;
                     break;
                 } else if (ret < 0)
                     return ret;

                 if (!s->root.next)
                     return 0;

             }
             head = s->root.next->frame;
 
             len = FFMIN(s->allocated_samples - s->out->nb_samples,
                         head->nb_samples);

             av_samples_copy(s->out->extended_data, head->extended_data,
                             s->out->nb_samples, 0, len, nb_channels,

                             link->format);

             s->out->nb_samples += len;

             if (len == head->nb_samples) {
                 av_frame_free(&head);

                 queue_pop(s);
             } else {
                 buffer_offset(link, head, len);
             }
         }

         out = s->out;
         s->out = NULL;

     }

     return ff_filter_frame(link, out);

 }
 

 static int request_frame(AVFilterLink *outlink)
 {
     FifoContext *fifo = outlink->src->priv;

     int ret = 0;

 
     if (!fifo->root.next) {

         if ((ret = ff_request_frame(outlink->src->inputs[0])) < 0) {
             if (ret == AVERROR_EOF && outlink->request_samples)
                 return return_audio_frame(outlink->src);

             return ret;

         }

         if (!fifo->root.next)
             return 0;

     }
 

     if (outlink->request_samples) {
         return return_audio_frame(outlink->src);
     } else {

         ret = ff_filter_frame(outlink, fifo->root.next->frame);

         queue_pop(fifo);
     }

     return ret;

 }
 

 static const AVFilterPad avfilter_vf_fifo_inputs[] = {
     {
         .name             = "default",
         .type             = AVMEDIA_TYPE_VIDEO,

         .filter_frame     = add_to_queue,

     },
     { NULL }
 };
 
 static const AVFilterPad avfilter_vf_fifo_outputs[] = {
     {
         .name          = "default",
         .type          = AVMEDIA_TYPE_VIDEO,
         .request_frame = request_frame,
     },
     { NULL }
 };
 

 AVFilter ff_vf_fifo = {

     .name      = "fifo",
     .description = NULL_IF_CONFIG_SMALL("Buffer input images and send them when they are requested."),
 
     .init      = init,
     .uninit    = uninit,
 
     .priv_size = sizeof(FifoContext),
 

     .inputs    = avfilter_vf_fifo_inputs,
     .outputs   = avfilter_vf_fifo_outputs,
 };
 
 static const AVFilterPad avfilter_af_afifo_inputs[] = {
     {
         .name             = "default",
         .type             = AVMEDIA_TYPE_AUDIO,

         .filter_frame     = add_to_queue,

     },
     { NULL }
 };
 
 static const AVFilterPad avfilter_af_afifo_outputs[] = {
     {
         .name          = "default",
         .type          = AVMEDIA_TYPE_AUDIO,
         .request_frame = request_frame,
     },
     { NULL }

 };

 AVFilter ff_af_afifo = {

     .name        = "afifo",
     .description = NULL_IF_CONFIG_SMALL("Buffer input frames and send them when they are requested."),
 
     .init      = init,
     .uninit    = uninit,
 
     .priv_size = sizeof(FifoContext),
 

     .inputs    = avfilter_af_afifo_inputs,
     .outputs   = avfilter_af_afifo_outputs,

 };