wrlib/load_ppm.c

   1 /* ppm.c - load PPM image from file
   2  *
   3  * Raster graphics library
   4  *
   5  * Copyright (c) 1997-2003 Alfredo K. Kojima
   6  *
   7  *  This library is free software; you can redistribute it and/or
   8  *  modify it under the terms of the GNU Library General Public
   9  *  License as published by the Free Software Foundation; either
  10  *  version 2 of the License, or (at your option) any later version.
  11  *
  12  *  This library 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  *  Library General Public License for more details.
  16  *
  17  *  You should have received a copy of the GNU Library General Public
  18  *  License along with this library; if not, write to the Free
  19  *  Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston,
  20  *  MA 02110-1301, USA.
  21  */
  22
  23 #include <config.h>
  24
  25 #include <X11/Xlib.h>
  26 #include <stdlib.h>
  27 #include <stdio.h>
  28 #include <string.h>
  29
  30 #include "wraster.h"
  31 #include "imgformat.h"
  32
  33 static RImage *load_graymap(FILE *file, int w, int h, int max, int raw)
  34 {
  35         RImage *image;
  36         unsigned char *ptr;
  37         char *buf;
  38         int x, y;
  39
  40         image = RCreateImage(w, h, 0);
  41         if (!image)
  42                 return NULL;
  43
  44         if (!raw)
  45                 return image;
  46
  47         if (max < 256) {
  48                 buf = malloc(w + 1);
  49                 if (!buf)
  50                         return NULL;
  51
  52                 ptr = image->data;
  53                 for (y = 0; y < h; y++) {
  54                         if (!fread(buf, w, 1, file)) {
  55                                 free(buf);
  56                                 RErrorCode = RERR_BADIMAGEFILE;
  57                                 return NULL;
  58                         }
  59
  60                         for (x = 0; x < w; x++) {
  61                                 *(ptr++) = buf[x];
  62                                 *(ptr++) = buf[x];
  63                                 *(ptr++) = buf[x];
  64                         }
  65                 }
  66                 free(buf);
  67         }
  68
  69         return image;
  70 }
  71
  72 static RImage *load_pixmap(FILE *file, int w, int h, int max, int raw)
  73 {
  74         RImage *image;
  75         int i;
  76         char buf[3];
  77         unsigned char *ptr;
  78
  79         image = RCreateImage(w, h, 0);
  80         if (!image)
  81                 return NULL;
  82
  83         if (!raw)
  84                 return image;
  85
  86         ptr = image->data;
  87         if (max < 256) {
  88                 i = 0;
  89                 while (i < w * h) {
  90                         if (fread(buf, 1, 3, file) != 3) {
  91                                 RErrorCode = RERR_BADIMAGEFILE;
  92                                 return NULL;
  93                         }
  94
  95                         *(ptr++) = buf[0];
  96                         *(ptr++) = buf[1];
  97                         *(ptr++) = buf[2];
  98                         i++;
  99                 }
 100         }
 101
 102         return image;
 103 }
 104
 105 RImage *RLoadPPM(const char *file_name)
 106 {
 107         FILE *file;
 108         RImage *image = NULL;
 109         char buffer[256];
 110         int w, h, m;
 111         int type;
 112
 113         file = fopen(file_name, "rb");
 114         if (!file) {
 115                 RErrorCode = RERR_OPEN;
 116                 return NULL;
 117         }
 118
 119         /* get signature */
 120         if (!fgets(buffer, 255, file)) {
 121                 RErrorCode = RERR_BADIMAGEFILE;
 122                 fclose(file);
 123                 return NULL;
 124         }
 125
 126         /* only accept raw pixmaps or graymaps */
 127         if (buffer[0] != 'P' || (buffer[1] != '5' && buffer[1] != '6')) {
 128                 RErrorCode = RERR_BADFORMAT;
 129                 fclose(file);
 130                 return NULL;
 131         }
 132
 133         type = buffer[1];
 134
 135         /* skip comments */
 136         while (1) {
 137                 if (!fgets(buffer, 255, file)) {
 138                         RErrorCode = RERR_BADIMAGEFILE;
 139                         fclose(file);
 140                         return NULL;
 141                 }
 142
 143                 if (buffer[0] != '#')
 144                         break;
 145         }
 146
 147         /* get size */
 148         if (sscanf(buffer, "%i %i", &w, &h) != 2 || w < 1 || h < 1) {
 149                 /* Short file */
 150                 RErrorCode = RERR_BADIMAGEFILE;
 151                 fclose(file);
 152                 return NULL;
 153         }
 154
 155         if (!fgets(buffer, 255, file)) {
 156                 RErrorCode = RERR_BADIMAGEFILE;
 157                 fclose(file);
 158                 return NULL;
 159         }
 160
 161         if (sscanf(buffer, "%i", &m) != 1 || m < 1) {
 162                 /* Short file */
 163                 RErrorCode = RERR_BADIMAGEFILE;
 164                 fclose(file);
 165                 return NULL;
 166         }
 167
 168         if (type == '5')
 169                 image = load_graymap(file, w, h, m, type == '5');
 170         else if (type == '6')
 171                 image = load_pixmap(file, w, h, m, type == '6');
 172
 173         fclose(file);
 174         return image;
 175 }