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, AVCodecContext *avctx,
  27                      const uint8_t **poutbuf, int *poutbuf_size,
  28                      const uint8_t *buf, int buf_size)
  29 {
  30     ParseContext *pc = s->priv_data;
  31     PNMContext pnmctx;
  32     int next;
  33
  34     for (; pc->overread > 0; pc->overread--) {
  35         pc->buffer[pc->index++]= pc->buffer[pc->overread_index++];
  36     }
  37 retry:
  38     if (pc->index) {
  39         pnmctx.bytestream_start =
  40         pnmctx.bytestream       = pc->buffer;
  41         pnmctx.bytestream_end   = pc->buffer + pc->index;
  42     } else {
  43         pnmctx.bytestream_start =
  44         pnmctx.bytestream       = (uint8_t *) buf; /* casts avoid warnings */
  45         pnmctx.bytestream_end   = (uint8_t *) buf + buf_size;
  46     }
  47     if (ff_pnm_decode_header(avctx, &pnmctx) < 0) {
  48         if (pnmctx.bytestream < pnmctx.bytestream_end) {
  49             if (pc->index) {
  50                 pc->index = 0;
  51             } else {
  52                 buf++;
  53                 buf_size--;
  54             }
  55             goto retry;
  56         }
  57 #if 0
  58         if (pc->index && pc->index * 2 + FF_INPUT_BUFFER_PADDING_SIZE < pc->buffer_size && buf_size > pc->index) {
  59             memcpy(pc->buffer + pc->index, buf, pc->index);
  60             pc->index += pc->index;
  61             buf       += pc->index;
  62             buf_size  -= pc->index;
  63             goto retry;
  64         }
  65 #endif
  66         next = END_NOT_FOUND;
  67     } else {
  68         next = pnmctx.bytestream - pnmctx.bytestream_start
  69                + avpicture_get_size(avctx->pix_fmt, avctx->width, avctx->height);
  70         if (pnmctx.bytestream_start != buf)
  71             next -= pc->index;
  72         if (next > buf_size)
  73             next = END_NOT_FOUND;
  74     }
  75
  76     if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
  77         *poutbuf      = NULL;
  78         *poutbuf_size = 0;
  79         return buf_size;
  80     }
  81     *poutbuf      = buf;
  82     *poutbuf_size = buf_size;
  83     return next;
  84 }
  85
  86 AVCodecParser pnm_parser = {
  87     { CODEC_ID_PGM, CODEC_ID_PGMYUV, CODEC_ID_PPM, CODEC_ID_PBM, CODEC_ID_PAM},
  88     sizeof(ParseContext),
  89     NULL,
  90     pnm_parse,
  91     ff_parse_close,
  92 };