libavcodec/pnm_parser.c

   1 /*
   2  * PNM image parser
   3  * Copyright (c) 2002, 2003 Fabrice Bellard
   4  *
   5  * This file is part of Libav.
   6  *
   7  * Libav 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  * Libav 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 Libav; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20  */
  21
  22 #include "libavutil/imgutils.h"
  23
  24 #include "parser.h" //for ParseContext
  25 #include "pnm.h"
  26
  27
  28 static int pnm_parse(AVCodecParserContext *s, AVCodecContext *avctx,
  29                      const uint8_t **poutbuf, int *poutbuf_size,
  30                      const uint8_t *buf, int buf_size)
  31 {
  32     ParseContext *pc = s->priv_data;
  33     PNMContext pnmctx;
  34     int next;
  35
  36     for (; pc->overread > 0; pc->overread--) {
  37         pc->buffer[pc->index++]= pc->buffer[pc->overread_index++];
  38     }
  39 retry:
  40     if (pc->index) {
  41         pnmctx.bytestream_start =
  42         pnmctx.bytestream       = pc->buffer;
  43         pnmctx.bytestream_end   = pc->buffer + pc->index;
  44     } else {
  45         pnmctx.bytestream_start =
  46         pnmctx.bytestream       = (uint8_t *) buf; /* casts avoid warnings */
  47         pnmctx.bytestream_end   = (uint8_t *) buf + buf_size;
  48     }
  49     if (ff_pnm_decode_header(avctx, &pnmctx) < 0) {
  50         if (pnmctx.bytestream < pnmctx.bytestream_end) {
  51             if (pc->index) {
  52                 pc->index = 0;
  53             } else {
  54                 buf++;
  55                 buf_size--;
  56             }
  57             goto retry;
  58         }
  59         next = END_NOT_FOUND;
  60     } else {
  61         next = pnmctx.bytestream - pnmctx.bytestream_start
  62                + av_image_get_buffer_size(avctx->pix_fmt, avctx->width, avctx->height, 1);
  63         if (pnmctx.bytestream_start != buf)
  64             next -= pc->index;
  65         if (next > buf_size)
  66             next = END_NOT_FOUND;
  67     }
  68
  69     if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
  70         *poutbuf      = NULL;
  71         *poutbuf_size = 0;
  72         return buf_size;
  73     }
  74     *poutbuf      = buf;
  75     *poutbuf_size = buf_size;
  76     return next;
  77 }
  78
  79 AVCodecParser ff_pnm_parser = {
  80     .codec_ids      = { AV_CODEC_ID_PGM, AV_CODEC_ID_PGMYUV, AV_CODEC_ID_PPM,
  81                         AV_CODEC_ID_PBM, AV_CODEC_ID_PAM },
  82     .priv_data_size = sizeof(ParseContext),
  83     .parser_parse   = pnm_parse,
  84     .parser_close   = ff_parse_close,
  85 };