/*
  * DCA parser
  * Copyright (C) 2004 Gildas Bazin
  * Copyright (C) 2004 Benjamin Zores
  * Copyright (C) 2006 Benjamin Larsson
  * Copyright (C) 2007 Konstantin Shishkov
  *
  * 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 "parser.h"
 #include "dca.h"

 #include "dca_parser.h"
 #include "get_bits.h"
 #include "put_bits.h"

 
 typedef struct DCAParseContext {
     ParseContext pc;
     uint32_t lastmarker;

     int size;
     int framesize;

     int hd_pos;

 } DCAParseContext;
 
 #define IS_MARKER(state, i, buf, buf_size) \
  ((state == DCA_MARKER_14B_LE && (i < buf_size-2) && (buf[i+1] & 0xF0) == 0xF0 && buf[i+2] == 0x07) \
  || (state == DCA_MARKER_14B_BE && (i < buf_size-2) && buf[i+1] == 0x07 && (buf[i+2] & 0xF0) == 0xF0) \

  || state == DCA_MARKER_RAW_LE || state == DCA_MARKER_RAW_BE || state == DCA_HD_MARKER)

 
 /**

  * Find the end of the current frame in the bitstream.

  * @return the position of the first byte of the next frame, or -1
  */
 static int dca_find_frame_end(DCAParseContext * pc1, const uint8_t * buf,
                               int buf_size)
 {
     int start_found, i;
     uint32_t state;
     ParseContext *pc = &pc1->pc;
 
     start_found = pc->frame_start_found;
     state = pc->state;
 
     i = 0;
     if (!start_found) {
         for (i = 0; i < buf_size; i++) {
             state = (state << 8) | buf[i];
             if (IS_MARKER(state, i, buf, buf_size)) {

                 if (!pc1->lastmarker || state == pc1->lastmarker || pc1->lastmarker == DCA_HD_MARKER) {

                     start_found = 1;
                     pc1->lastmarker = state;
                     break;
                 }
             }
         }
     }
     if (start_found) {
         for (; i < buf_size; i++) {

             pc1->size++;

             state = (state << 8) | buf[i];

             if (state == DCA_HD_MARKER && !pc1->hd_pos)
                 pc1->hd_pos = pc1->size;

             if (IS_MARKER(state, i, buf, buf_size) && (state == pc1->lastmarker || pc1->lastmarker == DCA_HD_MARKER)) {

                 if(pc1->framesize > pc1->size)
                     continue;

                 // We have to check that we really read a full frame here, and that it isn't a pure HD frame, because their size is not constant.
                 if(!pc1->framesize && state == pc1->lastmarker && state != DCA_HD_MARKER){

                     pc1->framesize = pc1->hd_pos ? pc1->hd_pos : pc1->size;
                 }

                 pc->frame_start_found = 0;
                 pc->state = -1;

                 pc1->size = 0;

                 return i - 3;
             }
         }
     }
     pc->frame_start_found = start_found;
     pc->state = state;
     return END_NOT_FOUND;
 }
 

 static av_cold int dca_parse_init(AVCodecParserContext * s)

 {
     DCAParseContext *pc1 = s->priv_data;
 
     pc1->lastmarker = 0;
     return 0;
 }
 

 int ff_dca_convert_bitstream(const uint8_t *src, int src_size, uint8_t *dst,
                              int max_size)
 {
     uint32_t mrk;
     int i, tmp;
     const uint16_t *ssrc = (const uint16_t *) src;
     uint16_t *sdst = (uint16_t *) dst;
     PutBitContext pb;
 
     if ((unsigned) src_size > (unsigned) max_size)
         src_size = max_size;
 
     mrk = AV_RB32(src);
     switch (mrk) {
     case DCA_MARKER_RAW_BE:
         memcpy(dst, src, src_size);
         return src_size;
     case DCA_MARKER_RAW_LE:
         for (i = 0; i < (src_size + 1) >> 1; i++)
             *sdst++ = av_bswap16(*ssrc++);
         return src_size;
     case DCA_MARKER_14B_BE:
     case DCA_MARKER_14B_LE:
         init_put_bits(&pb, dst, max_size);
         for (i = 0; i < (src_size + 1) >> 1; i++, src += 2) {
             tmp = ((mrk == DCA_MARKER_14B_BE) ? AV_RB16(src) : AV_RL16(src)) & 0x3FFF;
             put_bits(&pb, 14, tmp);
         }
         flush_put_bits(&pb);
         return (put_bits_count(&pb) + 7) >> 3;
     default:
         return AVERROR_INVALIDDATA;
     }
 }
 
 static int dca_parse_params(const uint8_t *buf, int buf_size, int *duration,
                             int *sample_rate)
 {
     GetBitContext gb;
     uint8_t hdr[12 + FF_INPUT_BUFFER_PADDING_SIZE] = { 0 };
     int ret, sample_blocks, sr_code;
 
     if (buf_size < 12)
         return AVERROR_INVALIDDATA;
 
     if ((ret = ff_dca_convert_bitstream(buf, 12, hdr, 12)) < 0)
         return ret;
 
     init_get_bits(&gb, hdr, 96);
 
     skip_bits_long(&gb, 39);
     sample_blocks = get_bits(&gb, 7) + 1;
     if (sample_blocks < 8)
         return AVERROR_INVALIDDATA;
     *duration = 256 * (sample_blocks / 8);
 
     skip_bits(&gb, 20);
     sr_code = get_bits(&gb, 4);

     *sample_rate = avpriv_dca_sample_rates[sr_code];

     if (*sample_rate == 0)
         return AVERROR_INVALIDDATA;
 
     return 0;
 }
 

 static int dca_parse(AVCodecParserContext * s,
                      AVCodecContext * avctx,

                      const uint8_t ** poutbuf, int *poutbuf_size,

                      const uint8_t * buf, int buf_size)
 {
     DCAParseContext *pc1 = s->priv_data;
     ParseContext *pc = &pc1->pc;

     int next, duration, sample_rate;

 
     if (s->flags & PARSER_FLAG_COMPLETE_FRAMES) {
         next = buf_size;
     } else {
         next = dca_find_frame_end(pc1, buf, buf_size);
 

         if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {

             *poutbuf = NULL;
             *poutbuf_size = 0;
             return buf_size;
         }
     }

 
     /* read the duration and sample rate from the frame header */
     if (!dca_parse_params(buf, buf_size, &duration, &sample_rate)) {
         s->duration = duration;

         avctx->sample_rate = sample_rate;

     } else
         s->duration = 0;
 

     *poutbuf = buf;

     *poutbuf_size = buf_size;
     return next;
 }
 

 AVCodecParser ff_dca_parser = {

     .codec_ids      = { AV_CODEC_ID_DTS },

     .priv_data_size = sizeof(DCAParseContext),
     .parser_init    = dca_parse_init,
     .parser_parse   = dca_parse,
     .parser_close   = ff_parse_close,

 };