/*

  * 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/audioconvert.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 {
     AVFilterBufferRef *buf;
     struct Buf        *next;
 } Buf;

 
 typedef struct {

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

 
     /**
      * When a specific number of output samples is requested, the partial
      * buffer is stored here
      */
     AVFilterBufferRef *buf_out;
     int allocated_samples;      ///< number of samples buf_out was allocated for

 } FifoContext;
 

 static av_cold int init(AVFilterContext *ctx, const char *args)

 {
     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;

         avfilter_unref_bufferp(&buf->buf);

         av_free(buf);

     }

     avfilter_unref_bufferp(&fifo->buf_out);

 }
 

 static int add_to_queue(AVFilterLink *inlink, AVFilterBufferRef *buf)

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

     inlink->cur_buf = NULL;

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

     if (!fifo->last->next) {
         avfilter_unref_buffer(buf);
         return AVERROR(ENOMEM);
     }
 

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

     fifo->last->buf = buf;

 
     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;
 }
 

 static int end_frame(AVFilterLink *inlink)
 {
     return 0;
 }

 static int draw_slice(AVFilterLink *inlink, int y, int h, int slice_dir)
 {
     return 0;
 }

 /**
  * Move data pointers and pts offset samples forward.
  */
 static void buffer_offset(AVFilterLink *link, AVFilterBufferRef *buf,
                           int offset)
 {
     int nb_channels = av_get_channel_layout_nb_channels(link->channel_layout);
     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(buf->audio->nb_samples > offset);
 
     for (i = 0; i < planes; i++)
         buf->extended_data[i] += block_align*offset;
     if (buf->data != buf->extended_data)
         memcpy(buf->data, buf->extended_data,
                FFMIN(planes, FF_ARRAY_ELEMS(buf->data)) * sizeof(*buf->data));
     buf->linesize[0] -= block_align*offset;
     buf->audio->nb_samples -= offset;
 
     if (buf->pts != AV_NOPTS_VALUE) {
         buf->pts += av_rescale_q(offset, (AVRational){1, link->sample_rate},
                                  link->time_base);
     }
 }
 
 static int calc_ptr_alignment(AVFilterBufferRef *buf)
 {
     int planes = av_sample_fmt_is_planar(buf->format) ?
                  av_get_channel_layout_nb_channels(buf->audio->channel_layout) : 1;
     int min_align = 128;
     int p;
 
     for (p = 0; p < planes; p++) {
         int cur_align = 128;
         while ((intptr_t)buf->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;
     AVFilterBufferRef *head = s->root.next->buf;
     AVFilterBufferRef *buf_out;
     int ret;
 
     if (!s->buf_out &&
         head->audio->nb_samples >= link->request_samples &&
         calc_ptr_alignment(head) >= 32) {
         if (head->audio->nb_samples == link->request_samples) {
             buf_out = head;
             queue_pop(s);
         } else {
             buf_out = avfilter_ref_buffer(head, AV_PERM_READ);

             if (!buf_out)
                 return AVERROR(ENOMEM);
 

             buf_out->audio->nb_samples = link->request_samples;
             buffer_offset(link, head, link->request_samples);
         }
     } else {
         int nb_channels = av_get_channel_layout_nb_channels(link->channel_layout);
 
         if (!s->buf_out) {
             s->buf_out = ff_get_audio_buffer(link, AV_PERM_WRITE,
                                              link->request_samples);
             if (!s->buf_out)
                 return AVERROR(ENOMEM);
 
             s->buf_out->audio->nb_samples = 0;
             s->buf_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->buf_out->audio->nb_samples < s->allocated_samples) {
             int len = FFMIN(s->allocated_samples - s->buf_out->audio->nb_samples,
                             head->audio->nb_samples);
 
             av_samples_copy(s->buf_out->extended_data, head->extended_data,
                             s->buf_out->audio->nb_samples, 0, len, nb_channels,
                             link->format);
             s->buf_out->audio->nb_samples += len;
 
             if (len == head->audio->nb_samples) {
                 avfilter_unref_buffer(head);
                 queue_pop(s);
 
                 if (!s->root.next &&
                     (ret = ff_request_frame(ctx->inputs[0])) < 0) {
                     if (ret == AVERROR_EOF) {
                         av_samples_set_silence(s->buf_out->extended_data,
                                                s->buf_out->audio->nb_samples,
                                                s->allocated_samples -
                                                s->buf_out->audio->nb_samples,
                                                nb_channels, link->format);
                         s->buf_out->audio->nb_samples = s->allocated_samples;
                         break;
                     }
                     return ret;
                 }
                 head = s->root.next->buf;
             } else {
                 buffer_offset(link, head, len);
             }
         }
         buf_out = s->buf_out;
         s->buf_out = NULL;
     }

     return ff_filter_samples(link, buf_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)

             return ret;
     }
 
     /* by doing this, we give ownership of the reference to the next filter,
      * so we don't have to worry about dereferencing it ourselves. */

     switch (outlink->type) {
     case AVMEDIA_TYPE_VIDEO:

         if ((ret = ff_start_frame(outlink, fifo->root.next->buf)) < 0 ||
             (ret = ff_draw_slice(outlink, 0, outlink->h, 1)) < 0 ||
             (ret = ff_end_frame(outlink)) < 0)
             return ret;
 

         queue_pop(fifo);

         break;
     case AVMEDIA_TYPE_AUDIO:

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

             ret = ff_filter_samples(outlink, fifo->root.next->buf);

             queue_pop(fifo);
         }

         break;
     default:
         return AVERROR(EINVAL);
     }

     return ret;

 }
 
 AVFilter avfilter_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    = (const AVFilterPad[]) {{ .name            = "default",
                                           .type            = AVMEDIA_TYPE_VIDEO,
                                           .get_video_buffer= ff_null_get_video_buffer,

                                           .start_frame     = add_to_queue,

                                           .draw_slice      = draw_slice,
                                           .end_frame       = end_frame,

                                           .min_perms       = AV_PERM_PRESERVE, },

                                         { .name = NULL}},
     .outputs   = (const AVFilterPad[]) {{ .name            = "default",
                                           .type            = AVMEDIA_TYPE_VIDEO,
                                           .request_frame   = request_frame, },
                                         { .name = NULL}},

 };

 
 AVFilter avfilter_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    = (const AVFilterPad[]) {{ .name             = "default",
                                           .type             = AVMEDIA_TYPE_AUDIO,
                                           .get_audio_buffer = ff_null_get_audio_buffer,
                                           .filter_samples   = add_to_queue,

                                           .min_perms        = AV_PERM_PRESERVE, },

                                         { .name = NULL}},
     .outputs   = (const AVFilterPad[]) {{ .name             = "default",
                                           .type             = AVMEDIA_TYPE_AUDIO,
                                           .request_frame    = request_frame, },
                                         { .name = NULL}},

 };