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
main(int argc,char * argv[])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
usage()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
png2pnm(FILE * png_file,FILE * pnm_file,FILE * alpha_file,volatile BOOL raw,BOOL alpha)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