libs/loaders/GP_PNM.c

   1 /*****************************************************************************
   2  * This file is part of gfxprim library.                                     *
   3  *                                                                           *
   4  * Gfxprim is free software; you can redistribute it and/or                  *
   5  * modify it under the terms of the GNU Lesser General Public                *
   6  * License as published by the Free Software Foundation; either              *
   7  * version 2.1 of the License, or (at your option) any later version.        *
   8  *                                                                           *
   9  * Gfxprim is distributed in the hope that it will be useful,                *
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of            *
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU         *
  12  * Lesser General Public License for more details.                           *
  13  *                                                                           *
  14  * You should have received a copy of the GNU Lesser General Public          *
  15  * License along with gfxprim; if not, write to the Free Software            *
  16  * Foundation, Inc., 51 Franklin Street, Fifth Floor,                        *
  17  * Boston, MA  02110-1301  USA                                               *
  18  *                                                                           *
  19  * Copyright (C) 2009-2010 Cyril Hrubis <metan@ucw.cz>                       *
  20  *                                                                           *
  21  *****************************************************************************/
  22
  23 #include <stdint.h>
  24 #include <inttypes.h>
  25
  26 #include <ctype.h>
  27 #include <errno.h>
  28 #include <string.h>
  29
  30 #include <GP_Debug.h>
  31
  32 #include "GP_PNM.h"
  33
  34 /*
  35
  36   PNM portable bitmap header
  37   --------------------------
  38
  39   Format:
  40
  41   a magick number value of 'P' and one of
  42    '1' - PBM 2bpp gray ASCII
  43    '2' - PGM gray      ASCII
  44    '3' - PPM rgb888    ASCII
  45    '4' - PBM 2bpp gray BINARY
  46    '5' - PGM gray      BINARY
  47    '6' - PPM rgb888    BINARY
  48   whitespace (blanks, TABs, CRs, LFs).
  49   ascii width
  50   whitespace
  51   ascii height
  52   whitespace
  53   maximal value (interval is 0 ... max) (not applicable for PBM)
  54   width * height ascii or binary values
  55
  56   lines starting with '#' are comments to the end of line
  57
  58  */
  59
  60 static void try_read_comments(FILE *f)
  61 {
  62         char c1, c2;
  63
  64         while (isspace(c1 = fgetc(f)));
  65
  66         ungetc(c1, f);
  67
  68         while ((c1 = fgetc(f)) == '#') {
  69                 do {
  70                         c2 = fgetc(f);
  71                 } while (c2 != '\n' && c2 != EOF);
  72         }
  73
  74         ungetc(c1, f);
  75 }
  76
  77
  78 static char *pnm_names[] = {
  79         "ASCII encoded PBM",
  80         "ASCII encoded PGM",
  81         "ASCII encoded PPM",
  82         "BINARY encoded PBM",
  83         "BINARY encoded PGM",
  84         "BINARY encoded PPM",
  85 };
  86
  87 FILE *GP_ReadPNM(const char *src_path, char *fmt,
  88                  uint32_t *w, uint32_t *h, uint32_t *depth)
  89 {
  90         FILE *f = fopen(src_path, "r");
  91         int ch;
  92
  93         if (f == NULL) {
  94                 GP_DEBUG(1, "Failed to open file '%s': %s",
  95                          src_path, strerror(errno));
  96                 return NULL;
  97         }
  98
  99         ch = fgetc(f);
 100
 101         if (ch != 'P') {
 102                 GP_DEBUG(1, "Invalid PNM header start '%c' (0x%2x) expecting 'P'",
 103                          isprint(ch) ? ch : ' ',  ch);
 104                 goto err1;
 105         }
 106
 107         ch = fgetc(f);
 108
 109         switch (ch) {
 110         case '4':
 111         case '1':
 112                 *depth = 1;
 113         break;
 114         case '2':
 115         case '3':
 116         case '5':
 117         case '6':
 118         break;
 119         default:
 120                 GP_DEBUG(1, "Invalid PNM format 'P%c' (0x%2x)",
 121                          isprint(ch) ? ch : ' ',  ch);
 122                 goto err1;
 123         }
 124
 125         *fmt = ch;
 126
 127         try_read_comments(f);
 128
 129         if (fscanf(f, "%"PRIu32"\n", w) < 1) {
 130                 GP_DEBUG(1, "Failed to read PNM header width");
 131                 goto err1;
 132         }
 133
 134         try_read_comments(f);
 135
 136         if (fscanf(f, "%"PRIu32"\n", h) < 1) {
 137                 GP_DEBUG(1, "Failed to read PNM header height");
 138                 goto err1;
 139         }
 140
 141         GP_DEBUG(2, "Have %s size %"PRIu32"x%"PRIu32,
 142                  pnm_names[*fmt - '1'], *w, *h);
 143
 144         if (*fmt == '1' || *fmt == '3')
 145                 return f;
 146
 147         try_read_comments(f);
 148
 149         if (fscanf(f, "%"PRIu32"\n", depth) < 1) {
 150                 GP_DEBUG(1, "Failed to read PNM header depth");
 151                 goto err1;
 152         }
 153
 154         return f;
 155 err1:
 156         fclose(f);
 157         return NULL;
 158 }
 159
 160 #define GFXPRIM_SIGNATURE "# Generated by gfxprim http://gfxprim.ucw.cz\n"
 161
 162 FILE *GP_WritePNM(const char *dst_path, char fmt,
 163                   uint32_t w, uint32_t h, uint32_t depth)
 164 {
 165         FILE *f = fopen(dst_path, "w");
 166         int ret;
 167
 168         ret = fprintf(f, "P%c\n"GFXPRIM_SIGNATURE
 169                          "%"PRIu32" %"PRIu32"\n%"PRIu32"\n",
 170                          fmt, w, h, depth);
 171
 172         if (ret < 0) {
 173                 GP_DEBUG(1, "Failed to write PNM header '%s' : %s",
 174                             dst_path, strerror(errno));
 175                 fclose(f);
 176                 return NULL;
 177         }
 178
 179         return f;
 180 }