1 /*
2 * wrjpgcom.c
3 *
4 * This file was part of the Independent JPEG Group's software:
5 * Copyright (C) 1994-1997, Thomas G. Lane.
6 * libjpeg-turbo Modifications:
7 * Copyright (C) 2014, D. R. Commander
8 * For conditions of distribution and use, see the accompanying README file.
9 *
10 * This file contains a very simple stand-alone application that inserts
11 * user-supplied text as a COM (comment) marker in a JFIF file.
12 * This may be useful as an example of the minimum logic needed to parse
13 * JPEG markers.
14 */
15
16 #define JPEG_CJPEG_DJPEG /* to get the command-line config symbols */
17 #include "jinclude.h" /* get auto-config symbols, <stdio.h> */
18
19 #ifndef HAVE_STDLIB_H /* <stdlib.h> should declare malloc() */
20 extern void * malloc ();
21 #endif
22 #include <ctype.h> /* to declare isupper(), tolower() */
23 #ifdef USE_SETMODE
24 #include <fcntl.h> /* to declare setmode()'s parameter macros */
25 /* If you have setmode() but not <io.h>, just delete this line: */
26 #include <io.h> /* to declare setmode() */
27 #endif
28
29 #ifdef USE_CCOMMAND /* command-line reader for Macintosh */
30 #ifdef __MWERKS__
31 #include <SIOUX.h> /* Metrowerks needs this */
32 #include <console.h> /* ... and this */
33 #endif
34 #ifdef THINK_C
35 #include <console.h> /* Think declares it here */
36 #endif
37 #endif
38
39 #ifdef DONT_USE_B_MODE /* define mode parameters for fopen() */
40 #define READ_BINARY "r"
41 #define WRITE_BINARY "w"
42 #else
43 #define READ_BINARY "rb"
44 #define WRITE_BINARY "wb"
45 #endif
46
47 #ifndef EXIT_FAILURE /* define exit() codes if not provided */
48 #define EXIT_FAILURE 1
49 #endif
50 #ifndef EXIT_SUCCESS
51 #define EXIT_SUCCESS 0
52 #endif
53
54 /* Reduce this value if your malloc() can't allocate blocks up to 64K.
55 * On DOS, compiling in large model is usually a better solution.
56 */
57
58 #ifndef MAX_COM_LENGTH
59 #define MAX_COM_LENGTH 65000L /* must be <= 65533 in any case */
60 #endif
61
62
63 /*
64 * These macros are used to read the input file and write the output file.
65 * To reuse this code in another application, you might need to change these.
66 */
67
68 static FILE * infile; /* input JPEG file */
69
70 /* Return next input byte, or EOF if no more */
71 #define NEXTBYTE() getc(infile)
72
73 static FILE * outfile; /* output JPEG file */
74
75 /* Emit an output byte */
76 #define PUTBYTE(x) putc((x), outfile)
77
78
79 /* Error exit handler */
80 #define ERREXIT(msg) (fprintf(stderr, "%s\n", msg), exit(EXIT_FAILURE))
81
82
83 /* Read one byte, testing for EOF */
84 static int
read_1_byte(void)85 read_1_byte (void)
86 {
87 int c;
88
89 c = NEXTBYTE();
90 if (c == EOF)
91 ERREXIT("Premature EOF in JPEG file");
92 return c;
93 }
94
95 /* Read 2 bytes, convert to unsigned int */
96 /* All 2-byte quantities in JPEG markers are MSB first */
97 static unsigned int
read_2_bytes(void)98 read_2_bytes (void)
99 {
100 int c1, c2;
101
102 c1 = NEXTBYTE();
103 if (c1 == EOF)
104 ERREXIT("Premature EOF in JPEG file");
105 c2 = NEXTBYTE();
106 if (c2 == EOF)
107 ERREXIT("Premature EOF in JPEG file");
108 return (((unsigned int) c1) << 8) + ((unsigned int) c2);
109 }
110
111
112 /* Routines to write data to output file */
113
114 static void
write_1_byte(int c)115 write_1_byte (int c)
116 {
117 PUTBYTE(c);
118 }
119
120 static void
write_2_bytes(unsigned int val)121 write_2_bytes (unsigned int val)
122 {
123 PUTBYTE((val >> 8) & 0xFF);
124 PUTBYTE(val & 0xFF);
125 }
126
127 static void
write_marker(int marker)128 write_marker (int marker)
129 {
130 PUTBYTE(0xFF);
131 PUTBYTE(marker);
132 }
133
134 static void
copy_rest_of_file(void)135 copy_rest_of_file (void)
136 {
137 int c;
138
139 while ((c = NEXTBYTE()) != EOF)
140 PUTBYTE(c);
141 }
142
143
144 /*
145 * JPEG markers consist of one or more 0xFF bytes, followed by a marker
146 * code byte (which is not an FF). Here are the marker codes of interest
147 * in this program. (See jdmarker.c for a more complete list.)
148 */
149
150 #define M_SOF0 0xC0 /* Start Of Frame N */
151 #define M_SOF1 0xC1 /* N indicates which compression process */
152 #define M_SOF2 0xC2 /* Only SOF0-SOF2 are now in common use */
153 #define M_SOF3 0xC3
154 #define M_SOF5 0xC5 /* NB: codes C4 and CC are NOT SOF markers */
155 #define M_SOF6 0xC6
156 #define M_SOF7 0xC7
157 #define M_SOF9 0xC9
158 #define M_SOF10 0xCA
159 #define M_SOF11 0xCB
160 #define M_SOF13 0xCD
161 #define M_SOF14 0xCE
162 #define M_SOF15 0xCF
163 #define M_SOI 0xD8 /* Start Of Image (beginning of datastream) */
164 #define M_EOI 0xD9 /* End Of Image (end of datastream) */
165 #define M_SOS 0xDA /* Start Of Scan (begins compressed data) */
166 #define M_COM 0xFE /* COMment */
167
168
169 /*
170 * Find the next JPEG marker and return its marker code.
171 * We expect at least one FF byte, possibly more if the compressor used FFs
172 * to pad the file. (Padding FFs will NOT be replicated in the output file.)
173 * There could also be non-FF garbage between markers. The treatment of such
174 * garbage is unspecified; we choose to skip over it but emit a warning msg.
175 * NB: this routine must not be used after seeing SOS marker, since it will
176 * not deal correctly with FF/00 sequences in the compressed image data...
177 */
178
179 static int
next_marker(void)180 next_marker (void)
181 {
182 int c;
183 int discarded_bytes = 0;
184
185 /* Find 0xFF byte; count and skip any non-FFs. */
186 c = read_1_byte();
187 while (c != 0xFF) {
188 discarded_bytes++;
189 c = read_1_byte();
190 }
191 /* Get marker code byte, swallowing any duplicate FF bytes. Extra FFs
192 * are legal as pad bytes, so don't count them in discarded_bytes.
193 */
194 do {
195 c = read_1_byte();
196 } while (c == 0xFF);
197
198 if (discarded_bytes != 0) {
199 fprintf(stderr, "Warning: garbage data found in JPEG file\n");
200 }
201
202 return c;
203 }
204
205
206 /*
207 * Read the initial marker, which should be SOI.
208 * For a JFIF file, the first two bytes of the file should be literally
209 * 0xFF M_SOI. To be more general, we could use next_marker, but if the
210 * input file weren't actually JPEG at all, next_marker might read the whole
211 * file and then return a misleading error message...
212 */
213
214 static int
first_marker(void)215 first_marker (void)
216 {
217 int c1, c2;
218
219 c1 = NEXTBYTE();
220 c2 = NEXTBYTE();
221 if (c1 != 0xFF || c2 != M_SOI)
222 ERREXIT("Not a JPEG file");
223 return c2;
224 }
225
226
227 /*
228 * Most types of marker are followed by a variable-length parameter segment.
229 * This routine skips over the parameters for any marker we don't otherwise
230 * want to process.
231 * Note that we MUST skip the parameter segment explicitly in order not to
232 * be fooled by 0xFF bytes that might appear within the parameter segment;
233 * such bytes do NOT introduce new markers.
234 */
235
236 static void
copy_variable(void)237 copy_variable (void)
238 /* Copy an unknown or uninteresting variable-length marker */
239 {
240 unsigned int length;
241
242 /* Get the marker parameter length count */
243 length = read_2_bytes();
244 write_2_bytes(length);
245 /* Length includes itself, so must be at least 2 */
246 if (length < 2)
247 ERREXIT("Erroneous JPEG marker length");
248 length -= 2;
249 /* Skip over the remaining bytes */
250 while (length > 0) {
251 write_1_byte(read_1_byte());
252 length--;
253 }
254 }
255
256 static void
skip_variable(void)257 skip_variable (void)
258 /* Skip over an unknown or uninteresting variable-length marker */
259 {
260 unsigned int length;
261
262 /* Get the marker parameter length count */
263 length = read_2_bytes();
264 /* Length includes itself, so must be at least 2 */
265 if (length < 2)
266 ERREXIT("Erroneous JPEG marker length");
267 length -= 2;
268 /* Skip over the remaining bytes */
269 while (length > 0) {
270 (void) read_1_byte();
271 length--;
272 }
273 }
274
275
276 /*
277 * Parse the marker stream until SOFn or EOI is seen;
278 * copy data to output, but discard COM markers unless keep_COM is true.
279 */
280
281 static int
scan_JPEG_header(int keep_COM)282 scan_JPEG_header (int keep_COM)
283 {
284 int marker;
285
286 /* Expect SOI at start of file */
287 if (first_marker() != M_SOI)
288 ERREXIT("Expected SOI marker first");
289 write_marker(M_SOI);
290
291 /* Scan miscellaneous markers until we reach SOFn. */
292 for (;;) {
293 marker = next_marker();
294 switch (marker) {
295 /* Note that marker codes 0xC4, 0xC8, 0xCC are not, and must not be,
296 * treated as SOFn. C4 in particular is actually DHT.
297 */
298 case M_SOF0: /* Baseline */
299 case M_SOF1: /* Extended sequential, Huffman */
300 case M_SOF2: /* Progressive, Huffman */
301 case M_SOF3: /* Lossless, Huffman */
302 case M_SOF5: /* Differential sequential, Huffman */
303 case M_SOF6: /* Differential progressive, Huffman */
304 case M_SOF7: /* Differential lossless, Huffman */
305 case M_SOF9: /* Extended sequential, arithmetic */
306 case M_SOF10: /* Progressive, arithmetic */
307 case M_SOF11: /* Lossless, arithmetic */
308 case M_SOF13: /* Differential sequential, arithmetic */
309 case M_SOF14: /* Differential progressive, arithmetic */
310 case M_SOF15: /* Differential lossless, arithmetic */
311 return marker;
312
313 case M_SOS: /* should not see compressed data before SOF */
314 ERREXIT("SOS without prior SOFn");
315 break;
316
317 case M_EOI: /* in case it's a tables-only JPEG stream */
318 return marker;
319
320 case M_COM: /* Existing COM: conditionally discard */
321 if (keep_COM) {
322 write_marker(marker);
323 copy_variable();
324 } else {
325 skip_variable();
326 }
327 break;
328
329 default: /* Anything else just gets copied */
330 write_marker(marker);
331 copy_variable(); /* we assume it has a parameter count... */
332 break;
333 }
334 } /* end loop */
335 }
336
337
338 /* Command line parsing code */
339
340 static const char * progname; /* program name for error messages */
341
342
343 static void
usage(void)344 usage (void)
345 /* complain about bad command line */
346 {
347 fprintf(stderr, "wrjpgcom inserts a textual comment in a JPEG file.\n");
348 fprintf(stderr, "You can add to or replace any existing comment(s).\n");
349
350 fprintf(stderr, "Usage: %s [switches] ", progname);
351 #ifdef TWO_FILE_COMMANDLINE
352 fprintf(stderr, "inputfile outputfile\n");
353 #else
354 fprintf(stderr, "[inputfile]\n");
355 #endif
356
357 fprintf(stderr, "Switches (names may be abbreviated):\n");
358 fprintf(stderr, " -replace Delete any existing comments\n");
359 fprintf(stderr, " -comment \"text\" Insert comment with given text\n");
360 fprintf(stderr, " -cfile name Read comment from named file\n");
361 fprintf(stderr, "Notice that you must put quotes around the comment text\n");
362 fprintf(stderr, "when you use -comment.\n");
363 fprintf(stderr, "If you do not give either -comment or -cfile on the command line,\n");
364 fprintf(stderr, "then the comment text is read from standard input.\n");
365 fprintf(stderr, "It can be multiple lines, up to %u characters total.\n",
366 (unsigned int) MAX_COM_LENGTH);
367 #ifndef TWO_FILE_COMMANDLINE
368 fprintf(stderr, "You must specify an input JPEG file name when supplying\n");
369 fprintf(stderr, "comment text from standard input.\n");
370 #endif
371
372 exit(EXIT_FAILURE);
373 }
374
375
376 static int
keymatch(char * arg,const char * keyword,int minchars)377 keymatch (char * arg, const char * keyword, int minchars)
378 /* Case-insensitive matching of (possibly abbreviated) keyword switches. */
379 /* keyword is the constant keyword (must be lower case already), */
380 /* minchars is length of minimum legal abbreviation. */
381 {
382 register int ca, ck;
383 register int nmatched = 0;
384
385 while ((ca = *arg++) != '\0') {
386 if ((ck = *keyword++) == '\0')
387 return 0; /* arg longer than keyword, no good */
388 if (isupper(ca)) /* force arg to lcase (assume ck is already) */
389 ca = tolower(ca);
390 if (ca != ck)
391 return 0; /* no good */
392 nmatched++; /* count matched characters */
393 }
394 /* reached end of argument; fail if it's too short for unique abbrev */
395 if (nmatched < minchars)
396 return 0;
397 return 1; /* A-OK */
398 }
399
400
401 /*
402 * The main program.
403 */
404
405 int
main(int argc,char ** argv)406 main (int argc, char **argv)
407 {
408 int argn;
409 char * arg;
410 int keep_COM = 1;
411 char * comment_arg = NULL;
412 FILE * comment_file = NULL;
413 unsigned int comment_length = 0;
414 int marker;
415
416 /* On Mac, fetch a command line. */
417 #ifdef USE_CCOMMAND
418 argc = ccommand(&argv);
419 #endif
420
421 progname = argv[0];
422 if (progname == NULL || progname[0] == 0)
423 progname = "wrjpgcom"; /* in case C library doesn't provide it */
424
425 /* Parse switches, if any */
426 for (argn = 1; argn < argc; argn++) {
427 arg = argv[argn];
428 if (arg[0] != '-')
429 break; /* not switch, must be file name */
430 arg++; /* advance over '-' */
431 if (keymatch(arg, "replace", 1)) {
432 keep_COM = 0;
433 } else if (keymatch(arg, "cfile", 2)) {
434 if (++argn >= argc) usage();
435 if ((comment_file = fopen(argv[argn], "r")) == NULL) {
436 fprintf(stderr, "%s: can't open %s\n", progname, argv[argn]);
437 exit(EXIT_FAILURE);
438 }
439 } else if (keymatch(arg, "comment", 1)) {
440 if (++argn >= argc) usage();
441 comment_arg = argv[argn];
442 /* If the comment text starts with '"', then we are probably running
443 * under MS-DOG and must parse out the quoted string ourselves. Sigh.
444 */
445 if (comment_arg[0] == '"') {
446 comment_arg = (char *) malloc((size_t) MAX_COM_LENGTH);
447 if (comment_arg == NULL)
448 ERREXIT("Insufficient memory");
449 if (strlen(argv[argn]) + 2 >= (size_t) MAX_COM_LENGTH) {
450 fprintf(stderr, "Comment text may not exceed %u bytes\n",
451 (unsigned int) MAX_COM_LENGTH);
452 exit(EXIT_FAILURE);
453 }
454 strcpy(comment_arg, argv[argn]+1);
455 for (;;) {
456 comment_length = (unsigned int) strlen(comment_arg);
457 if (comment_length > 0 && comment_arg[comment_length-1] == '"') {
458 comment_arg[comment_length-1] = '\0'; /* zap terminating quote */
459 break;
460 }
461 if (++argn >= argc)
462 ERREXIT("Missing ending quote mark");
463 if (strlen(comment_arg) + strlen(argv[argn]) + 2 >=
464 (size_t) MAX_COM_LENGTH) {
465 fprintf(stderr, "Comment text may not exceed %u bytes\n",
466 (unsigned int) MAX_COM_LENGTH);
467 exit(EXIT_FAILURE);
468 }
469 strcat(comment_arg, " ");
470 strcat(comment_arg, argv[argn]);
471 }
472 } else if (strlen(argv[argn]) >= (size_t) MAX_COM_LENGTH) {
473 fprintf(stderr, "Comment text may not exceed %u bytes\n",
474 (unsigned int) MAX_COM_LENGTH);
475 exit(EXIT_FAILURE);
476 }
477 comment_length = (unsigned int) strlen(comment_arg);
478 } else
479 usage();
480 }
481
482 /* Cannot use both -comment and -cfile. */
483 if (comment_arg != NULL && comment_file != NULL)
484 usage();
485 /* If there is neither -comment nor -cfile, we will read the comment text
486 * from stdin; in this case there MUST be an input JPEG file name.
487 */
488 if (comment_arg == NULL && comment_file == NULL && argn >= argc)
489 usage();
490
491 /* Open the input file. */
492 if (argn < argc) {
493 if ((infile = fopen(argv[argn], READ_BINARY)) == NULL) {
494 fprintf(stderr, "%s: can't open %s\n", progname, argv[argn]);
495 exit(EXIT_FAILURE);
496 }
497 } else {
498 /* default input file is stdin */
499 #ifdef USE_SETMODE /* need to hack file mode? */
500 setmode(fileno(stdin), O_BINARY);
501 #endif
502 #ifdef USE_FDOPEN /* need to re-open in binary mode? */
503 if ((infile = fdopen(fileno(stdin), READ_BINARY)) == NULL) {
504 fprintf(stderr, "%s: can't open stdin\n", progname);
505 exit(EXIT_FAILURE);
506 }
507 #else
508 infile = stdin;
509 #endif
510 }
511
512 /* Open the output file. */
513 #ifdef TWO_FILE_COMMANDLINE
514 /* Must have explicit output file name */
515 if (argn != argc-2) {
516 fprintf(stderr, "%s: must name one input and one output file\n",
517 progname);
518 usage();
519 }
520 if ((outfile = fopen(argv[argn+1], WRITE_BINARY)) == NULL) {
521 fprintf(stderr, "%s: can't open %s\n", progname, argv[argn+1]);
522 exit(EXIT_FAILURE);
523 }
524 #else
525 /* Unix style: expect zero or one file name */
526 if (argn < argc-1) {
527 fprintf(stderr, "%s: only one input file\n", progname);
528 usage();
529 }
530 /* default output file is stdout */
531 #ifdef USE_SETMODE /* need to hack file mode? */
532 setmode(fileno(stdout), O_BINARY);
533 #endif
534 #ifdef USE_FDOPEN /* need to re-open in binary mode? */
535 if ((outfile = fdopen(fileno(stdout), WRITE_BINARY)) == NULL) {
536 fprintf(stderr, "%s: can't open stdout\n", progname);
537 exit(EXIT_FAILURE);
538 }
539 #else
540 outfile = stdout;
541 #endif
542 #endif /* TWO_FILE_COMMANDLINE */
543
544 /* Collect comment text from comment_file or stdin, if necessary */
545 if (comment_arg == NULL) {
546 FILE * src_file;
547 int c;
548
549 comment_arg = (char *) malloc((size_t) MAX_COM_LENGTH);
550 if (comment_arg == NULL)
551 ERREXIT("Insufficient memory");
552 comment_length = 0;
553 src_file = (comment_file != NULL ? comment_file : stdin);
554 while ((c = getc(src_file)) != EOF) {
555 if (comment_length >= (unsigned int) MAX_COM_LENGTH) {
556 fprintf(stderr, "Comment text may not exceed %u bytes\n",
557 (unsigned int) MAX_COM_LENGTH);
558 exit(EXIT_FAILURE);
559 }
560 comment_arg[comment_length++] = (char) c;
561 }
562 if (comment_file != NULL)
563 fclose(comment_file);
564 }
565
566 /* Copy JPEG headers until SOFn marker;
567 * we will insert the new comment marker just before SOFn.
568 * This (a) causes the new comment to appear after, rather than before,
569 * existing comments; and (b) ensures that comments come after any JFIF
570 * or JFXX markers, as required by the JFIF specification.
571 */
572 marker = scan_JPEG_header(keep_COM);
573 /* Insert the new COM marker, but only if nonempty text has been supplied */
574 if (comment_length > 0) {
575 write_marker(M_COM);
576 write_2_bytes(comment_length + 2);
577 while (comment_length > 0) {
578 write_1_byte(*comment_arg++);
579 comment_length--;
580 }
581 }
582 /* Duplicate the remainder of the source file.
583 * Note that any COM markers occuring after SOF will not be touched.
584 */
585 write_marker(marker);
586 copy_rest_of_file();
587
588 /* All done. */
589 exit(EXIT_SUCCESS);
590 return 0; /* suppress no-return-value warnings */
591 }
592