/*
  * VC-1 and WMV3 parser
  * Copyright (c) 2006-2007 Konstantin Shishkov
  * Partly based on vc9.c (c) 2005 Anonymous, Alex Beregszaszi, Michael Niedermayer
  *
  * 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

  * VC-1 and WMV3 parser
  */

 #include "parser.h"
 #include "vc1.h"

 #include "get_bits.h"
 
 typedef struct {
     ParseContext pc;
     VC1Context v;
 } VC1ParseContext;
 
 static void vc1_extract_headers(AVCodecParserContext *s, AVCodecContext *avctx,
                                 const uint8_t *buf, int buf_size)
 {
     VC1ParseContext *vpc = s->priv_data;
     GetBitContext gb;
     const uint8_t *start, *end, *next;
     uint8_t *buf2 = av_mallocz(buf_size + FF_INPUT_BUFFER_PADDING_SIZE);
 
     vpc->v.s.avctx = avctx;
     vpc->v.parse_only = 1;
     next = buf;

     s->repeat_pict = 0;

 
     for(start = buf, end = buf + buf_size; next < end; start = next){
         int buf2_size, size;
 
         next = find_next_marker(start + 4, end);
         size = next - start - 4;
         buf2_size = vc1_unescape_buffer(start + 4, size, buf2);
         init_get_bits(&gb, buf2, buf2_size * 8);
         if(size <= 0) continue;
         switch(AV_RB32(start)){
         case VC1_CODE_SEQHDR:

             ff_vc1_decode_sequence_header(avctx, &vpc->v, &gb);

             break;
         case VC1_CODE_ENTRYPOINT:

             ff_vc1_decode_entry_point(avctx, &vpc->v, &gb);

             break;
         case VC1_CODE_FRAME:
             if(vpc->v.profile < PROFILE_ADVANCED)

                 ff_vc1_parse_frame_header    (&vpc->v, &gb);

             else

                 ff_vc1_parse_frame_header_adv(&vpc->v, &gb);

             /* keep AV_PICTURE_TYPE_BI internal to VC1 */
             if (vpc->v.s.pict_type == AV_PICTURE_TYPE_BI)
                 s->pict_type = AV_PICTURE_TYPE_B;

             else
                 s->pict_type = vpc->v.s.pict_type;
 

             if (avctx->ticks_per_frame > 1){
                 // process pulldown flags
                 s->repeat_pict = 1;
                 // Pulldown flags are only valid when 'broadcast' has been set.
                 // So ticks_per_frame will be 2
                 if (vpc->v.rff){
                     // repeat field
                     s->repeat_pict = 2;
                 }else if (vpc->v.rptfrm){
                     // repeat frames
                     s->repeat_pict = vpc->v.rptfrm * 2 + 1;
                 }
             }
 

             break;
         }
     }
 
     av_free(buf2);
 }

 
 /**

  * 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 vc1_find_frame_end(ParseContext *pc, const uint8_t *buf,
                                int buf_size) {
     int pic_found, i;
     uint32_t state;
 
     pic_found= pc->frame_start_found;
     state= pc->state;
 
     i=0;
     if(!pic_found){
         for(i=0; i<buf_size; i++){
             state= (state<<8) | buf[i];
             if(state == VC1_CODE_FRAME || state == VC1_CODE_FIELD){
                 i++;
                 pic_found=1;
                 break;
             }
         }
     }
 
     if(pic_found){
         /* EOF considered as end of frame */
         if (buf_size == 0)
             return 0;
         for(; i<buf_size; i++){
             state= (state<<8) | buf[i];
             if(IS_MARKER(state) && state != VC1_CODE_FIELD && state != VC1_CODE_SLICE){
                 pc->frame_start_found=0;
                 pc->state=-1;
                 return i-3;
             }
         }
     }
     pc->frame_start_found= pic_found;
     pc->state= state;
     return END_NOT_FOUND;
 }
 
 static int vc1_parse(AVCodecParserContext *s,
                            AVCodecContext *avctx,

                            const uint8_t **poutbuf, int *poutbuf_size,

                            const uint8_t *buf, int buf_size)
 {

     VC1ParseContext *vpc = s->priv_data;

     int next;
 
     if(s->flags & PARSER_FLAG_COMPLETE_FRAMES){
         next= buf_size;
     }else{

         next= vc1_find_frame_end(&vpc->pc, buf, buf_size);

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

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

 
     vc1_extract_headers(s, avctx, buf, buf_size);
 

     *poutbuf = buf;

     *poutbuf_size = buf_size;
     return next;
 }
 
 static int vc1_split(AVCodecContext *avctx,
                            const uint8_t *buf, int buf_size)
 {
     int i;
     uint32_t state= -1;

     int charged=0;

 
     for(i=0; i<buf_size; i++){
         state= (state<<8) | buf[i];

         if(IS_MARKER(state)){
             if(state == VC1_CODE_SEQHDR || state == VC1_CODE_ENTRYPOINT){
                 charged=1;
             }else if(charged){
                 return i-3;
             }
         }

     }
     return 0;
 }
 

 static int vc1_parse_init(AVCodecParserContext *s)
 {
     VC1ParseContext *vpc = s->priv_data;
     vpc->v.s.slice_context_count = 1;

     return ff_vc1_init_common(&vpc->v);

 }
 

 AVCodecParser ff_vc1_parser = {

     .codec_ids      = { AV_CODEC_ID_VC1 },

     .priv_data_size = sizeof(VC1ParseContext),

     .parser_init    = vc1_parse_init,

     .parser_parse   = vc1_parse,

     .parser_close   = ff_parse_close,

     .split          = vc1_split,

 };