/*
  * DVB subtitle parser for FFmpeg

  * Copyright (c) 2005 Ian Caulfield

  *
  * 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 "avcodec.h"

 #include "get_bits.h"

 
 /* Parser (mostly) copied from dvdsub.c */
 
 #define PARSE_BUF_SIZE  (65536)
 
 
 /* parser definition */
 typedef struct DVBSubParseContext {
     uint8_t *packet_buf;
     int packet_start;
     int packet_index;
     int in_packet;
 } DVBSubParseContext;
 

 static av_cold int dvbsub_parse_init(AVCodecParserContext *s)

 {
     DVBSubParseContext *pc = s->priv_data;
     pc->packet_buf = av_malloc(PARSE_BUF_SIZE);
 
     return 0;
 }
 
 static int dvbsub_parse(AVCodecParserContext *s,
                         AVCodecContext *avctx,

                         const uint8_t **poutbuf, int *poutbuf_size,

                         const uint8_t *buf, int buf_size)
 {
     DVBSubParseContext *pc = s->priv_data;
     uint8_t *p, *p_end;

     int i, len, buf_pos = 0;

     av_dlog(avctx, "DVB parse packet pts=%"PRIx64", lpts=%"PRIx64", cpts=%"PRIx64":\n",

             s->pts, s->last_pts, s->cur_frame_pts[s->cur_frame_start_index]);
 
     for (i=0; i < buf_size; i++)
     {

         av_dlog(avctx, "%02x ", buf[i]);

         if (i % 16 == 15)

             av_dlog(avctx, "\n");

     }
 
     if (i % 16 != 0)

         av_dlog(avctx, "\n");

 
     *poutbuf = NULL;
     *poutbuf_size = 0;
 
     s->fetch_timestamp = 1;
 

     if (s->last_pts != s->pts && s->pts != AV_NOPTS_VALUE) /* Start of a new packet */

     {
         if (pc->packet_index != pc->packet_start)
         {

             av_dlog(avctx, "Discarding %d bytes\n",

                     pc->packet_index - pc->packet_start);

         }
 
         pc->packet_start = 0;
         pc->packet_index = 0;
 
         if (buf_size < 2 || buf[0] != 0x20 || buf[1] != 0x00) {

             av_dlog(avctx, "Bad packet header\n");

             return -1;
         }
 
         buf_pos = 2;
 
         pc->in_packet = 1;
     } else {
         if (pc->packet_start != 0)
         {
             if (pc->packet_index != pc->packet_start)
             {
                 memmove(pc->packet_buf, pc->packet_buf + pc->packet_start,
                             pc->packet_index - pc->packet_start);
 
                 pc->packet_index -= pc->packet_start;
                 pc->packet_start = 0;
             } else {
                 pc->packet_start = 0;
                 pc->packet_index = 0;
             }
         }
     }
 
     if (buf_size - buf_pos + pc->packet_index > PARSE_BUF_SIZE)
         return -1;
 
 /* if not currently in a packet, discard data */
     if (pc->in_packet == 0)
         return buf_size;
 
     memcpy(pc->packet_buf + pc->packet_index, buf + buf_pos, buf_size - buf_pos);
     pc->packet_index += buf_size - buf_pos;
 
     p = pc->packet_buf;
     p_end = pc->packet_buf + pc->packet_index;
 
     while (p < p_end)
     {
         if (*p == 0x0f)
         {
             if (p + 6 <= p_end)
             {
                 len = AV_RB16(p + 4);
 
                 if (p + len + 6 <= p_end)
                 {
                     *poutbuf_size += len + 6;
 
                     p += len + 6;
                 } else
                     break;
             } else
                 break;
         } else if (*p == 0xff) {
             if (p + 1 < p_end)
             {

                 av_dlog(avctx, "Junk at end of packet\n");

             }
             pc->packet_index = p - pc->packet_buf;
             pc->in_packet = 0;
             break;
         } else {
             av_log(avctx, AV_LOG_ERROR, "Junk in packet\n");
 
             pc->packet_index = p - pc->packet_buf;
             pc->in_packet = 0;
             break;
         }
     }
 
     if (*poutbuf_size > 0)
     {
         *poutbuf = pc->packet_buf;
         pc->packet_start = *poutbuf_size;
     }
 

     if (s->pts == AV_NOPTS_VALUE)
         s->pts = s->last_pts;

 
     return buf_size;
 }
 

 static av_cold void dvbsub_parse_close(AVCodecParserContext *s)

 {
     DVBSubParseContext *pc = s->priv_data;
     av_freep(&pc->packet_buf);
 }
 

 AVCodecParser ff_dvbsub_parser = {

     .codec_ids      = { AV_CODEC_ID_DVB_SUBTITLE },

     .priv_data_size = sizeof(DVBSubParseContext),
     .parser_init    = dvbsub_parse_init,
     .parser_parse   = dvbsub_parse,
     .parser_close   = dvbsub_parse_close,

 };