/*
  * Generic frame queue
  * Copyright (c) 2016 Nicolas George
  *
  * 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
  */
 
 #include "libavutil/avassert.h"
 #include "framequeue.h"
 
 static inline FFFrameBucket *bucket(FFFrameQueue *fq, size_t idx)
 {
     return &fq->queue[(fq->tail + idx) & (fq->allocated - 1)];
 }
 
 void ff_framequeue_global_init(FFFrameQueueGlobal *fqg)
 {
 }
 
 static void check_consistency(FFFrameQueue *fq)
 {

 #if defined(ASSERT_LEVEL) && ASSERT_LEVEL >= 2

     uint64_t nb_samples = 0;
     size_t i;
 
     av_assert0(fq->queued == fq->total_frames_head - fq->total_frames_tail);
     for (i = 0; i < fq->queued; i++)
         nb_samples += bucket(fq, i)->frame->nb_samples;
     av_assert0(nb_samples == fq->total_samples_head - fq->total_samples_tail);
 #endif
 }
 
 void ff_framequeue_init(FFFrameQueue *fq, FFFrameQueueGlobal *fqg)
 {
     fq->queue = &fq->first_bucket;
     fq->allocated = 1;
 }
 
 void ff_framequeue_free(FFFrameQueue *fq)
 {
     while (fq->queued) {
         AVFrame *frame = ff_framequeue_take(fq);
         av_frame_free(&frame);
     }
     if (fq->queue != &fq->first_bucket)
         av_freep(&fq->queue);
 }
 
 int ff_framequeue_add(FFFrameQueue *fq, AVFrame *frame)
 {
     FFFrameBucket *b;
 
     check_consistency(fq);
     if (fq->queued == fq->allocated) {
         if (fq->allocated == 1) {
             size_t na = 8;
             FFFrameBucket *nq = av_realloc_array(NULL, na, sizeof(*nq));
             if (!nq)
                 return AVERROR(ENOMEM);
             nq[0] = fq->queue[0];
             fq->queue = nq;
             fq->allocated = na;
         } else {
             size_t na = fq->allocated << 1;
             FFFrameBucket *nq = av_realloc_array(fq->queue, na, sizeof(*nq));
             if (!nq)
                 return AVERROR(ENOMEM);
             if (fq->tail + fq->queued > fq->allocated)
                 memmove(nq + fq->allocated, nq,
                         (fq->tail + fq->queued - fq->allocated) * sizeof(*nq));
             fq->queue = nq;
             fq->allocated = na;
         }
     }
     b = bucket(fq, fq->queued);
     b->frame = frame;
     fq->queued++;
     fq->total_frames_head++;
     fq->total_samples_head += frame->nb_samples;
     check_consistency(fq);
     return 0;
 }
 
 AVFrame *ff_framequeue_take(FFFrameQueue *fq)
 {
     FFFrameBucket *b;
 
     check_consistency(fq);
     av_assert1(fq->queued);
     b = bucket(fq, 0);
     fq->queued--;
     fq->tail++;
     fq->tail &= fq->allocated - 1;
     fq->total_frames_tail++;
     fq->total_samples_tail += b->frame->nb_samples;

     fq->samples_skipped = 0;

     check_consistency(fq);
     return b->frame;
 }
 
 AVFrame *ff_framequeue_peek(FFFrameQueue *fq, size_t idx)
 {
     FFFrameBucket *b;
 
     check_consistency(fq);
     av_assert1(idx < fq->queued);
     b = bucket(fq, idx);
     check_consistency(fq);
     return b->frame;
 }

 
 void ff_framequeue_skip_samples(FFFrameQueue *fq, size_t samples, AVRational time_base)
 {
     FFFrameBucket *b;
     size_t bytes;
     int planar, planes, i;
 
     check_consistency(fq);
     av_assert1(fq->queued);
     b = bucket(fq, 0);
     av_assert1(samples < b->frame->nb_samples);
     planar = av_sample_fmt_is_planar(b->frame->format);
     planes = planar ? b->frame->channels : 1;
     bytes = samples * av_get_bytes_per_sample(b->frame->format);
     if (!planar)
         bytes *= b->frame->channels;
     if (b->frame->pts != AV_NOPTS_VALUE)
         b->frame->pts += av_rescale_q(samples, av_make_q(1, b->frame->sample_rate), time_base);
     b->frame->nb_samples -= samples;
     b->frame->linesize[0] -= bytes;
     for (i = 0; i < planes; i++)
         b->frame->extended_data[i] += bytes;
     for (i = 0; i < planes && i < AV_NUM_DATA_POINTERS; i++)
         b->frame->data[i] = b->frame->extended_data[i];
     fq->total_samples_tail += samples;

     fq->samples_skipped = 1;

     ff_framequeue_update_peeked(fq, 0);
 }