libavcodec/pnm.c

   1 /*
   2  * PNM image format
   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 #include "avcodec.h"
  22 #include "pnm.h"
  23
  24 static inline int pnm_space(int c)
  25 {
  26     return c == ' ' || c == '\n' || c == '\r' || c == '\t';
  27 }
  28
  29 static void pnm_get(PNMContext *sc, char *str, int buf_size)
  30 {
  31     char *s;
  32     int c;
  33
  34     /* skip spaces and comments */
  35     for(;;) {
  36         c = *sc->bytestream++;
  37         if (c == '#')  {
  38             do  {
  39                 c = *sc->bytestream++;
  40             } while (c != '\n' && sc->bytestream < sc->bytestream_end);
  41         } else if (!pnm_space(c)) {
  42             break;
  43         }
  44     }
  45
  46     s = str;
  47     while (sc->bytestream < sc->bytestream_end && !pnm_space(c)) {
  48         if ((s - str)  < buf_size - 1)
  49             *s++ = c;
  50         c = *sc->bytestream++;
  51     }
  52     *s = '\0';
  53 }
  54
  55 int ff_pnm_decode_header(AVCodecContext *avctx, PNMContext * const s){
  56     char buf1[32], tuple_type[32];
  57     int h, w, depth, maxval;
  58
  59     pnm_get(s, buf1, sizeof(buf1));
  60     if (!strcmp(buf1, "P4")) {
  61         avctx->pix_fmt = PIX_FMT_MONOWHITE;
  62     } else if (!strcmp(buf1, "P5")) {
  63         if (avctx->codec_id == CODEC_ID_PGMYUV)
  64             avctx->pix_fmt = PIX_FMT_YUV420P;
  65         else
  66             avctx->pix_fmt = PIX_FMT_GRAY8;
  67     } else if (!strcmp(buf1, "P6")) {
  68         avctx->pix_fmt = PIX_FMT_RGB24;
  69     } else if (!strcmp(buf1, "P7")) {
  70         w = -1;
  71         h = -1;
  72         maxval = -1;
  73         depth = -1;
  74         tuple_type[0] = '\0';
  75         for(;;) {
  76             pnm_get(s, buf1, sizeof(buf1));
  77             if (!strcmp(buf1, "WIDTH")) {
  78                 pnm_get(s, buf1, sizeof(buf1));
  79                 w = strtol(buf1, NULL, 10);
  80             } else if (!strcmp(buf1, "HEIGHT")) {
  81                 pnm_get(s, buf1, sizeof(buf1));
  82                 h = strtol(buf1, NULL, 10);
  83             } else if (!strcmp(buf1, "DEPTH")) {
  84                 pnm_get(s, buf1, sizeof(buf1));
  85                 depth = strtol(buf1, NULL, 10);
  86             } else if (!strcmp(buf1, "MAXVAL")) {
  87                 pnm_get(s, buf1, sizeof(buf1));
  88                 maxval = strtol(buf1, NULL, 10);
  89             } else if (!strcmp(buf1, "TUPLETYPE")) {
  90                 pnm_get(s, tuple_type, sizeof(tuple_type));
  91             } else if (!strcmp(buf1, "ENDHDR")) {
  92                 break;
  93             } else {
  94                 return -1;
  95             }
  96         }
  97         /* check that all tags are present */
  98         if (w <= 0 || h <= 0 || maxval <= 0 || depth <= 0 || tuple_type[0] == '\0' || avcodec_check_dimensions(avctx, w, h))
  99             return -1;
 100
 101         avctx->width = w;
 102         avctx->height = h;
 103         if (depth == 1) {
 104             if (maxval == 1)
 105                 avctx->pix_fmt = PIX_FMT_MONOWHITE;
 106             else
 107                 avctx->pix_fmt = PIX_FMT_GRAY8;
 108         } else if (depth == 3) {
 109             avctx->pix_fmt = PIX_FMT_RGB24;
 110         } else if (depth == 4) {
 111             avctx->pix_fmt = PIX_FMT_RGB32;
 112         } else {
 113             return -1;
 114         }
 115         return 0;
 116     } else {
 117         return -1;
 118     }
 119     pnm_get(s, buf1, sizeof(buf1));
 120     avctx->width = atoi(buf1);
 121     if (avctx->width <= 0)
 122         return -1;
 123     pnm_get(s, buf1, sizeof(buf1));
 124     avctx->height = atoi(buf1);
 125     if(avcodec_check_dimensions(avctx, avctx->width, avctx->height))
 126         return -1;
 127     if (avctx->pix_fmt != PIX_FMT_MONOWHITE) {
 128         pnm_get(s, buf1, sizeof(buf1));
 129         s->maxval = atoi(buf1);
 130         if(s->maxval >= 256 && avctx->pix_fmt == PIX_FMT_GRAY8) {
 131             avctx->pix_fmt = PIX_FMT_GRAY16BE;
 132             if (s->maxval != 65535)
 133                 avctx->pix_fmt = PIX_FMT_GRAY16;
 134         }
 135     }
 136     /* more check if YUV420 */
 137     if (avctx->pix_fmt == PIX_FMT_YUV420P) {
 138         if ((avctx->width & 1) != 0)
 139             return -1;
 140         h = (avctx->height * 2);
 141         if ((h % 3) != 0)
 142             return -1;
 143         h /= 3;
 144         avctx->height = h;
 145     }
 146     return 0;
 147 }