1 /* 2 * png2pnm.c --- conversion from PNG-file to PGM/PPM-file 3 * copyright (C) 1999,2017 by Willem van Schaik <willem at schaik.com> 4 * 5 * version 1.0 - 1999.10.15 - First version. 6 * 1.1 - 2017.04.22 - Add buffer-size check (Glenn Randers-Pehrson) 7 * 1.2 - 2017.08.24 - Fix potential overflow in buffer-size check 8 * (Glenn Randers-Pehrson) 9 * 1.3 - 2017.08.28 - Add PNGMINUS_UNUSED (Christian Hesse) 10 * 11 * Permission to use, copy, modify, and distribute this software and 12 * its documentation for any purpose and without fee is hereby granted, 13 * provided that the above copyright notice appear in all copies and 14 * that both that copyright notice and this permission notice appear in 15 * supporting documentation. This software is provided "as is" without 16 * express or implied warranty. 17 */ 18 19 #include <stdio.h> 20 #include <stdlib.h> 21 #ifdef __TURBOC__ 22 #include <mem.h> 23 #include <fcntl.h> 24 #endif 25 #include <zlib.h> 26 27 #ifndef BOOL 28 #define BOOL unsigned char 29 #endif 30 #ifndef TRUE 31 #define TRUE (BOOL) 1 32 #endif 33 #ifndef FALSE 34 #define FALSE (BOOL) 0 35 #endif 36 37 #ifdef __TURBOC__ 38 #define STDIN 0 39 #define STDOUT 1 40 #define STDERR 2 41 #endif 42 43 /* to make png2pnm verbose so we can find problems (needs to be before png.h) */ 44 #ifndef PNG_DEBUG 45 #define PNG_DEBUG 0 46 #endif 47 48 49 #include "png.h" 50 51 /* Define png_jmpbuf() in case we are using a pre-1.0.6 version of libpng */ 52 #ifndef png_jmpbuf 53 # define png_jmpbuf(png_ptr) ((png_ptr)->jmpbuf) 54 #endif 55 56 #ifndef PNGMINUS_UNUSED 57 /* Unused formal parameter warnings are silenced using the following macro 58 * which is expected to have no bad effects on performance (optimizing 59 * compilers will probably remove it entirely). 60 */ 61 # define PNGMINUS_UNUSED(param) (void)param 62 #endif 63 64 /* function prototypes */ 65 66 int main (int argc, char *argv[]); 67 void usage (); 68 BOOL png2pnm (FILE *png_file, FILE *pnm_file, FILE *alpha_file, BOOL raw, 69 BOOL alpha); 70 71 /* 72 * main 73 */ 74 75 int main(int argc, char *argv[]) 76 { 77 FILE *fp_rd = stdin; 78 FILE *fp_wr = stdout; 79 FILE *fp_al = NULL; 80 BOOL raw = TRUE; 81 BOOL alpha = FALSE; 82 int argi; 83 84 for (argi = 1; argi < argc; argi++) 85 { 86 if (argv[argi][0] == '-') 87 { 88 switch (argv[argi][1]) 89 { 90 case 'n': 91 raw = FALSE; 92 break; 93 case 'r': 94 raw = TRUE; 95 break; 96 case 'a': 97 alpha = TRUE; 98 argi++; 99 if ((fp_al = fopen (argv[argi], "wb")) == NULL) 100 { 101 fprintf (stderr, "PNM2PNG\n"); 102 fprintf (stderr, "Error: can not create alpha-channel file %s\n", 103 argv[argi]); 104 exit (1); 105 } 106 break; 107 case 'h': 108 case '?': 109 usage(); 110 exit(0); 111 break; 112 default: 113 fprintf (stderr, "PNG2PNM\n"); 114 fprintf (stderr, "Error: unknown option %s\n", argv[argi]); 115 usage(); 116 exit(1); 117 break; 118 } /* end switch */ 119 } 120 else if (fp_rd == stdin) 121 { 122 if ((fp_rd = fopen (argv[argi], "rb")) == NULL) 123 { 124 fprintf (stderr, "PNG2PNM\n"); 125 fprintf (stderr, "Error: file %s does not exist\n", argv[argi]); 126 exit (1); 127 } 128 } 129 else if (fp_wr == stdout) 130 { 131 if ((fp_wr = fopen (argv[argi], "wb")) == NULL) 132 { 133 fprintf (stderr, "PNG2PNM\n"); 134 fprintf (stderr, "Error: can not create file %s\n", argv[argi]); 135 exit (1); 136 } 137 } 138 else 139 { 140 fprintf (stderr, "PNG2PNM\n"); 141 fprintf (stderr, "Error: too many parameters\n"); 142 usage(); 143 exit(1); 144 } 145 } /* end for */ 146 147 #ifdef __TURBOC__ 148 /* set stdin/stdout if required to binary */ 149 if (fp_rd == stdin) 150 { 151 setmode (STDIN, O_BINARY); 152 } 153 if ((raw) && (fp_wr == stdout)) 154 { 155 setmode (STDOUT, O_BINARY); 156 } 157 #endif 158 159 /* call the conversion program itself */ 160 if (png2pnm (fp_rd, fp_wr, fp_al, raw, alpha) == FALSE) 161 { 162 fprintf (stderr, "PNG2PNM\n"); 163 fprintf (stderr, "Error: unsuccessful conversion of PNG-image\n"); 164 exit(1); 165 } 166 167 /* close input file */ 168 fclose (fp_rd); 169 /* close output file */ 170 fclose (fp_wr); 171 /* close alpha file */ 172 if (alpha) 173 fclose (fp_al); 174 175 return 0; 176 } 177 178 /* 179 * usage 180 */ 181 182 void usage() 183 { 184 fprintf (stderr, "PNG2PNM\n"); 185 fprintf (stderr, " by Willem van Schaik, 1999\n"); 186 #ifdef __TURBOC__ 187 fprintf (stderr, " for Turbo-C and Borland-C compilers\n"); 188 #else 189 fprintf (stderr, " for Linux (and Unix) compilers\n"); 190 #endif 191 fprintf (stderr, "Usage: png2pnm [options] <file>.png [<file>.pnm]\n"); 192 fprintf (stderr, " or: ... | png2pnm [options]\n"); 193 fprintf (stderr, "Options:\n"); 194 fprintf (stderr, 195 " -r[aw] write pnm-file in binary format (P4/P5/P6) (default)\n"); 196 fprintf (stderr, " -n[oraw] write pnm-file in ascii format (P1/P2/P3)\n"); 197 fprintf (stderr, 198 " -a[lpha] <file>.pgm write PNG alpha channel as pgm-file\n"); 199 fprintf (stderr, " -h | -? print this help-information\n"); 200 } 201 202 /* 203 * png2pnm 204 */ 205 206 BOOL png2pnm (FILE *png_file, FILE *pnm_file, FILE *alpha_file, 207 volatile BOOL raw, BOOL alpha) 208 { 209 png_struct *png_ptr = NULL; 210 png_info *info_ptr = NULL; 211 png_byte buf[8]; 212 png_byte *png_pixels = NULL; 213 png_byte **row_pointers = NULL; 214 png_byte *pix_ptr = NULL; 215 png_uint_32 row_bytes; 216 217 png_uint_32 width; 218 png_uint_32 height; 219 int bit_depth; 220 int channels; 221 int color_type; 222 int alpha_present; 223 int row, col; 224 int ret; 225 int i; 226 long dep_16; 227 228 /* read and check signature in PNG file */ 229 ret = fread (buf, 1, 8, png_file); 230 if (ret != 8) 231 return FALSE; 232 233 ret = png_sig_cmp (buf, 0, 8); 234 if (ret) 235 return FALSE; 236 237 /* create png and info structures */ 238 239 png_ptr = png_create_read_struct (png_get_libpng_ver(NULL), 240 NULL, NULL, NULL); 241 if (!png_ptr) 242 return FALSE; /* out of memory */ 243 244 info_ptr = png_create_info_struct (png_ptr); 245 if (!info_ptr) 246 { 247 png_destroy_read_struct (&png_ptr, NULL, NULL); 248 return FALSE; /* out of memory */ 249 } 250 251 if (setjmp (png_jmpbuf(png_ptr))) 252 { 253 png_destroy_read_struct (&png_ptr, &info_ptr, NULL); 254 return FALSE; 255 } 256 257 /* set up the input control for C streams */ 258 png_init_io (png_ptr, png_file); 259 png_set_sig_bytes (png_ptr, 8); /* we already read the 8 signature bytes */ 260 261 /* read the file information */ 262 png_read_info (png_ptr, info_ptr); 263 264 /* get size and bit-depth of the PNG-image */ 265 png_get_IHDR (png_ptr, info_ptr, 266 &width, &height, &bit_depth, &color_type, 267 NULL, NULL, NULL); 268 269 /* set-up the transformations */ 270 271 /* transform paletted images into full-color rgb */ 272 if (color_type == PNG_COLOR_TYPE_PALETTE) 273 png_set_expand (png_ptr); 274 /* expand images to bit-depth 8 (only applicable for grayscale images) */ 275 if (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8) 276 png_set_expand (png_ptr); 277 /* transform transparency maps into full alpha-channel */ 278 if (png_get_valid (png_ptr, info_ptr, PNG_INFO_tRNS)) 279 png_set_expand (png_ptr); 280 281 #ifdef NJET 282 /* downgrade 16-bit images to 8-bit */ 283 if (bit_depth == 16) 284 png_set_strip_16 (png_ptr); 285 /* transform grayscale images into full-color */ 286 if (color_type == PNG_COLOR_TYPE_GRAY || 287 color_type == PNG_COLOR_TYPE_GRAY_ALPHA) 288 png_set_gray_to_rgb (png_ptr); 289 /* only if file has a file gamma, we do a correction */ 290 if (png_get_gAMA (png_ptr, info_ptr, &file_gamma)) 291 png_set_gamma (png_ptr, (double) 2.2, file_gamma); 292 #endif 293 294 /* all transformations have been registered; now update info_ptr data, 295 * get rowbytes and channels, and allocate image memory */ 296 297 png_read_update_info (png_ptr, info_ptr); 298 299 /* get the new color-type and bit-depth (after expansion/stripping) */ 300 png_get_IHDR (png_ptr, info_ptr, &width, &height, &bit_depth, &color_type, 301 NULL, NULL, NULL); 302 303 /* check for 16-bit files */ 304 if (bit_depth == 16) 305 { 306 raw = FALSE; 307 #ifdef __TURBOC__ 308 pnm_file->flags &= ~((unsigned) _F_BIN); 309 #endif 310 } 311 312 /* calculate new number of channels and store alpha-presence */ 313 if (color_type == PNG_COLOR_TYPE_GRAY) 314 channels = 1; 315 else if (color_type == PNG_COLOR_TYPE_GRAY_ALPHA) 316 channels = 2; 317 else if (color_type == PNG_COLOR_TYPE_RGB) 318 channels = 3; 319 else if (color_type == PNG_COLOR_TYPE_RGB_ALPHA) 320 channels = 4; 321 else 322 channels = 0; /* should never happen */ 323 alpha_present = (channels - 1) % 2; 324 325 /* check if alpha is expected to be present in file */ 326 if (alpha && !alpha_present) 327 { 328 fprintf (stderr, "PNG2PNM\n"); 329 fprintf (stderr, "Error: PNG-file doesn't contain alpha channel\n"); 330 exit (1); 331 } 332 333 /* row_bytes is the width x number of channels x (bit-depth / 8) */ 334 row_bytes = png_get_rowbytes (png_ptr, info_ptr); 335 336 if ((row_bytes == 0 || (size_t)height > ((size_t)(-1))/(size_t)row_bytes)) 337 { 338 /* too big */ 339 png_destroy_read_struct (&png_ptr, &info_ptr, NULL); 340 return FALSE; 341 } 342 if ((png_pixels = (png_byte *) 343 malloc ((size_t)row_bytes * (size_t)height * sizeof (png_byte))) == NULL) 344 { 345 png_destroy_read_struct (&png_ptr, &info_ptr, NULL); 346 return FALSE; 347 } 348 349 if ((row_pointers = (png_byte **) 350 malloc ((size_t)height * sizeof (png_bytep))) == NULL) 351 { 352 png_destroy_read_struct (&png_ptr, &info_ptr, NULL); 353 free (png_pixels); 354 png_pixels = NULL; 355 return FALSE; 356 } 357 358 /* set the individual row_pointers to point at the correct offsets */ 359 for (i = 0; i < ((int) height); i++) 360 row_pointers[i] = png_pixels + i * row_bytes; 361 362 /* now we can go ahead and just read the whole image */ 363 png_read_image (png_ptr, row_pointers); 364 365 /* read rest of file, and get additional chunks in info_ptr - REQUIRED */ 366 png_read_end (png_ptr, info_ptr); 367 368 /* clean up after the read, and free any memory allocated - REQUIRED */ 369 png_destroy_read_struct (&png_ptr, &info_ptr, (png_infopp) NULL); 370 371 /* write header of PNM file */ 372 373 if ((color_type == PNG_COLOR_TYPE_GRAY) || 374 (color_type == PNG_COLOR_TYPE_GRAY_ALPHA)) 375 { 376 fprintf (pnm_file, "%s\n", (raw) ? "P5" : "P2"); 377 fprintf (pnm_file, "%d %d\n", (int) width, (int) height); 378 fprintf (pnm_file, "%ld\n", ((1L << (int) bit_depth) - 1L)); 379 } 380 else if ((color_type == PNG_COLOR_TYPE_RGB) || 381 (color_type == PNG_COLOR_TYPE_RGB_ALPHA)) 382 { 383 fprintf (pnm_file, "%s\n", (raw) ? "P6" : "P3"); 384 fprintf (pnm_file, "%d %d\n", (int) width, (int) height); 385 fprintf (pnm_file, "%ld\n", ((1L << (int) bit_depth) - 1L)); 386 } 387 388 /* write header of PGM file with alpha channel */ 389 390 if ((alpha) && 391 ((color_type == PNG_COLOR_TYPE_GRAY_ALPHA) || 392 (color_type == PNG_COLOR_TYPE_RGB_ALPHA))) 393 { 394 fprintf (alpha_file, "%s\n", (raw) ? "P5" : "P2"); 395 fprintf (alpha_file, "%d %d\n", (int) width, (int) height); 396 fprintf (alpha_file, "%ld\n", ((1L << (int) bit_depth) - 1L)); 397 } 398 399 /* write data to PNM file */ 400 pix_ptr = png_pixels; 401 402 for (row = 0; row < (int) height; row++) 403 { 404 for (col = 0; col < (int) width; col++) 405 { 406 for (i = 0; i < (channels - alpha_present); i++) 407 { 408 if (raw) 409 fputc ((int) *pix_ptr++ , pnm_file); 410 else 411 if (bit_depth == 16){ 412 dep_16 = (long) *pix_ptr++; 413 fprintf (pnm_file, "%ld ", (dep_16 << 8) + ((long) *pix_ptr++)); 414 } 415 else 416 fprintf (pnm_file, "%ld ", (long) *pix_ptr++); 417 } 418 if (alpha_present) 419 { 420 if (!alpha) 421 { 422 pix_ptr++; /* alpha */ 423 if (bit_depth == 16) 424 pix_ptr++; 425 } 426 else /* output alpha-channel as pgm file */ 427 { 428 if (raw) 429 fputc ((int) *pix_ptr++ , alpha_file); 430 else 431 if (bit_depth == 16) 432 { 433 dep_16 = (long) *pix_ptr++; 434 fprintf (alpha_file, "%ld ", (dep_16 << 8) + (long) *pix_ptr++); 435 } 436 else 437 fprintf (alpha_file, "%ld ", (long) *pix_ptr++); 438 } 439 } /* if alpha_present */ 440 441 if (!raw) 442 if (col % 4 == 3) 443 fprintf (pnm_file, "\n"); 444 } /* end for col */ 445 446 if (!raw) 447 if (col % 4 != 0) 448 fprintf (pnm_file, "\n"); 449 } /* end for row */ 450 451 if (row_pointers != (unsigned char**) NULL) 452 free (row_pointers); 453 if (png_pixels != (unsigned char*) NULL) 454 free (png_pixels); 455 456 PNGMINUS_UNUSED(raw); /* to quiet a Coverity defect */ 457 return TRUE; 458 459 } /* end of source */ 460 461
