/*
  * MJPEG parser

  * Copyright (c) 2000, 2001 Fabrice Bellard

  * Copyright (c) 2003 Alex Beregszaszi
  * Copyright (c) 2003-2004 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

  * MJPEG parser.
  */
 
 #include "parser.h"
 

 typedef struct MJPEGParserContext{
     ParseContext pc;

     int size;

 }MJPEGParserContext;

 
 /**

  * 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 find_frame_end(MJPEGParserContext *m, const uint8_t *buf, int buf_size){
     ParseContext *pc= &m->pc;

     int vop_found, i;

     uint32_t state;

 
     vop_found= pc->frame_start_found;
     state= pc->state;
 
     i=0;
     if(!vop_found){

         for(i=0; i<buf_size;){

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

             if(state>=0xFFC00000 && state<=0xFFFEFFFF){
                 if(state>=0xFFD80000 && state<=0xFFD8FFFF){
                     i++;
                     vop_found=1;
                     break;
                 }else if(state<0xFFD00000 || state>0xFFD9FFFF){
                     m->size= (state&0xFFFF)-1;
                 }

             }

             if(m->size>0){
                 int size= FFMIN(buf_size-i, m->size);
                 i+=size;
                 m->size-=size;
                 state=0;
                 continue;
             }else
                 i++;

         }
     }
 
     if(vop_found){
         /* EOF considered as end of frame */
         if (buf_size == 0)
             return 0;

         for(; i<buf_size;){

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

             if(state>=0xFFC00000 && state<=0xFFFEFFFF){
                 if(state>=0xFFD80000 && state<=0xFFD8FFFF){
                     pc->frame_start_found=0;
                     pc->state=0;
                     return i-3;
                 } else if(state<0xFFD00000 || state>0xFFD9FFFF){
                     m->size= (state&0xFFFF)-1;
                 }

             }

             if(m->size>0){
                 int size= FFMIN(buf_size-i, m->size);
                 i+=size;
                 m->size-=size;
                 state=0;
                 continue;
             }else
                 i++;

         }
     }
     pc->frame_start_found= vop_found;
     pc->state= state;
     return END_NOT_FOUND;
 }
 
 static int jpeg_parse(AVCodecParserContext *s,

                       AVCodecContext *avctx,
                       const uint8_t **poutbuf, int *poutbuf_size,
                       const uint8_t *buf, int buf_size)

 {

     MJPEGParserContext *m = s->priv_data;
     ParseContext *pc = &m->pc;

     int next;
 

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

         next= find_frame_end(m, buf, buf_size);

         if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
             *poutbuf = NULL;
             *poutbuf_size = 0;
             return buf_size;
         }

     }

 
     *poutbuf = buf;
     *poutbuf_size = buf_size;
     return next;
 }
 
 

 AVCodecParser ff_mjpeg_parser = {

     .codec_ids      = { CODEC_ID_MJPEG },

     .priv_data_size = sizeof(MJPEGParserContext),

     .parser_parse   = jpeg_parse,
     .parser_close   = ff_parse_close,

 };