pnm_loader.c

   1 /*
   2  * PNM image files loader
   3  *
   4  * copyleft (C) 2005-2010 Reimar Döffinger <Reimar.Doeffinger@gmx.de>
   5  *
   6  * This file is part of MPlayer.
   7  *
   8  * MPlayer is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * MPlayer is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License along
  19  * with MPlayer; if not, write to the Free Software Foundation, Inc.,
  20  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  21  *
  22  * You can alternatively redistribute this file and/or
  23  * modify it under the terms of the GNU Lesser General Public
  24  * License as published by the Free Software Foundation; either
  25  * version 2.1 of the License, or (at your option) any later version.
  26  */
  27
  28 /**
  29  * \file pnm_loader.c
  30  * \brief PNM image files loader
  31  */
  32
  33 #include <stdlib.h>
  34 #include <stdint.h>
  35 #include <stdio.h>
  36 #include <ctype.h>
  37 #include "pnm_loader.h"
  38
  39 /**
  40  * \brief skips whitespace and comments
  41  * \param f file to read from
  42  */
  43 static void ppm_skip(FILE *f) {
  44   int c, comment = 0;
  45   do {
  46     c = fgetc(f);
  47     if (c == '#')
  48       comment = 1;
  49     if (c == '\n')
  50       comment = 0;
  51   } while (c != EOF && (isspace(c) || comment));
  52   if (c != EOF)
  53     ungetc(c, f);
  54 }
  55
  56 #define MAXDIM (16 * 1024)
  57
  58 uint8_t *read_pnm(FILE *f, int *width, int *height,
  59                   int *bytes_per_pixel, int *maxval) {
  60   uint8_t *data;
  61   int type;
  62   unsigned w, h, m, val, bpp;
  63   *width = *height = *bytes_per_pixel = *maxval = 0;
  64   ppm_skip(f);
  65   if (fgetc(f) != 'P')
  66     return NULL;
  67   type = fgetc(f);
  68   if (type != '5' && type != '6')
  69     return NULL;
  70   ppm_skip(f);
  71   if (fscanf(f, "%u", &w) != 1)
  72     return NULL;
  73   ppm_skip(f);
  74   if (fscanf(f, "%u", &h) != 1)
  75     return NULL;
  76   ppm_skip(f);
  77   if (fscanf(f, "%u", &m) != 1)
  78     return NULL;
  79   val = fgetc(f);
  80   if (!isspace(val))
  81     return NULL;
  82   if (w > MAXDIM || h > MAXDIM)
  83     return NULL;
  84   bpp = (m > 255) ? 2 : 1;
  85   if (type == '6')
  86     bpp *= 3;
  87   data = malloc(w * h * bpp);
  88   if (fread(data, w * bpp, h, f) != h) {
  89     free(data);
  90     return NULL;
  91   }
  92   *width  = w;
  93   *height = h;
  94   *bytes_per_pixel = bpp;
  95   *maxval = m;
  96   return data;
  97 }