libavcodec/pnm_parser.c

   1 /*
   2  * PNM image parser
   3  * Copyright (c) 2002, 2003 Fabrice Bellard.
   4  *
   5  * This file is part of FFmpeg.
   6  *
   7  * FFmpeg is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Lesser General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2.1 of the License, or (at your option) any later version.
  11  *
  12  * FFmpeg is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public
  18  * License along with FFmpeg; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20  */
  21
  22 #include "parser.h" //for ParseContext
  23 #include "pnm.h"
  24
  25
  26 static int pnm_parse(AVCodecParserContext *s,
  27                            AVCodecContext *avctx,
  28                            const uint8_t **poutbuf, int *poutbuf_size,
  29                            const uint8_t *buf, int buf_size)
  30 {
  31     ParseContext *pc = s->priv_data;
  32     PNMContext pnmctx;
  33     int next;
  34
  35     for(; pc->overread>0; pc->overread--){
  36         pc->buffer[pc->index++]= pc->buffer[pc->overread_index++];
  37     }
  38 retry:
  39     if(pc->index){
  40         pnmctx.bytestream_start=
  41         pnmctx.bytestream= pc->buffer;
  42         pnmctx.bytestream_end= pc->buffer + pc->index;
  43     }else{
  44         pnmctx.bytestream_start=
  45         pnmctx.bytestream= (uint8_t *) buf; /* casts avoid warnings */
  46         pnmctx.bytestream_end= (uint8_t *) buf + buf_size;
  47     }
  48     if(ff_pnm_decode_header(avctx, &pnmctx) < 0){
  49         if(pnmctx.bytestream < pnmctx.bytestream_end){
  50             if(pc->index){
  51                 pc->index=0;
  52             }else{
  53                 buf++;
  54                 buf_size--;
  55             }
  56             goto retry;
  57         }
  58 #if 0
  59         if(pc->index && pc->index*2 + FF_INPUT_BUFFER_PADDING_SIZE < pc->buffer_size && buf_size > pc->index){
  60             memcpy(pc->buffer + pc->index, buf, pc->index);
  61             pc->index += pc->index;
  62             buf += pc->index;
  63             buf_size -= pc->index;
  64             goto retry;
  65         }
  66 #endif
  67         next= END_NOT_FOUND;
  68     }else{
  69         next= pnmctx.bytestream - pnmctx.bytestream_start
  70             + avpicture_get_size(avctx->pix_fmt, avctx->width, avctx->height);
  71         if(pnmctx.bytestream_start!=buf)
  72             next-= pc->index;
  73         if(next > buf_size)
  74             next= END_NOT_FOUND;
  75     }
  76
  77     if(ff_combine_frame(pc, next, &buf, &buf_size)<0){
  78         *poutbuf = NULL;
  79         *poutbuf_size = 0;
  80         return buf_size;
  81     }
  82     *poutbuf = buf;
  83     *poutbuf_size = buf_size;
  84     return next;
  85 }
  86
  87 AVCodecParser pnm_parser = {
  88     { CODEC_ID_PGM, CODEC_ID_PGMYUV, CODEC_ID_PPM, CODEC_ID_PBM, CODEC_ID_PAM},
  89     sizeof(ParseContext),
  90     NULL,
  91     pnm_parse,
  92     ff_parse_close,
  93 };