1 /* 2 * wrjpgcom.c 3 * 4 * Copyright (C) 1994-1997, Thomas G. Lane. 5 * Modified 2015-2017 by Guido Vollbeding. 6 * This file is part of the Independent JPEG Group's software. 7 * For conditions of distribution and use, see the accompanying README file. 8 * 9 * This file contains a very simple stand-alone application that inserts 10 * user-supplied text as a COM (comment) marker in a JFIF file. 11 * This may be useful as an example of the minimum logic needed to parse 12 * JPEG markers. 13 */ 14 15 #define JPEG_CJPEG_DJPEG /* to get the command-line config symbols */ 16 #include "jinclude.h" /* get auto-config symbols, <stdio.h> */ 17 18 #ifndef HAVE_STDLIB_H /* <stdlib.h> should declare malloc() */ 19 extern void * malloc (); 20 #endif 21 #include <ctype.h> /* to declare isupper(), tolower() */ 22 #ifdef USE_SETMODE 23 #include <fcntl.h> /* to declare setmode()'s parameter macros */ 24 /* If you have setmode() but not <io.h>, just delete this line: */ 25 #include <io.h> /* to declare setmode() */ 26 #endif 27 28 #ifdef USE_CCOMMAND /* command-line reader for Macintosh */ 29 #ifdef __MWERKS__ 30 #include <SIOUX.h> /* Metrowerks needs this */ 31 #include <console.h> /* ... and this */ 32 #endif 33 #ifdef THINK_C 34 #include <console.h> /* Think declares it here */ 35 #endif 36 #endif 37 38 #ifdef DONT_USE_B_MODE /* define mode parameters for fopen() */ 39 #define READ_BINARY "r" 40 #define WRITE_BINARY "w" 41 #else 42 #ifdef VMS /* VMS is very nonstandard */ 43 #define READ_BINARY "rb", "ctx=stm" 44 #define WRITE_BINARY "wb", "ctx=stm" 45 #else /* standard ANSI-compliant case */ 46 #define READ_BINARY "rb" 47 #define WRITE_BINARY "wb" 48 #endif 49 #endif 50 51 #ifndef EXIT_FAILURE /* define exit() codes if not provided */ 52 #define EXIT_FAILURE 1 53 #endif 54 #ifndef EXIT_SUCCESS 55 #ifdef VMS 56 #define EXIT_SUCCESS 1 /* VMS is very nonstandard */ 57 #else 58 #define EXIT_SUCCESS 0 59 #endif 60 #endif 61 62 /* Reduce this value if your malloc() can't allocate blocks up to 64K. 63 * On DOS, compiling in large model is usually a better solution. 64 */ 65 66 #ifndef MAX_COM_LENGTH 67 #define MAX_COM_LENGTH 65000L /* must be <= 65533 in any case */ 68 #endif 69 70 71 /* 72 * These macros are used to read the input file and write the output file. 73 * To reuse this code in another application, you might need to change these. 74 */ 75 76 static FILE * infile; /* input JPEG file */ 77 78 /* Return next input byte, or EOF if no more */ 79 #define NEXTBYTE() getc(infile) 80 81 static FILE * outfile; /* output JPEG file */ 82 83 /* Emit an output byte */ 84 #define PUTBYTE(x) putc((x), outfile) 85 86 87 /* Error exit handler */ 88 #define ERREXIT(msg) (fprintf(stderr, "%s\n", msg), exit(EXIT_FAILURE)) 89 90 91 /* Read one byte, testing for EOF */ 92 static int 93 read_1_byte (void) 94 { 95 int c; 96 97 c = NEXTBYTE(); 98 if (c == EOF) 99 ERREXIT("Premature EOF in JPEG file"); 100 return c; 101 } 102 103 /* Read 2 bytes, convert to unsigned int */ 104 /* All 2-byte quantities in JPEG markers are MSB first */ 105 static unsigned int 106 read_2_bytes (void) 107 { 108 int c1, c2; 109 110 c1 = NEXTBYTE(); 111 if (c1 == EOF) 112 ERREXIT("Premature EOF in JPEG file"); 113 c2 = NEXTBYTE(); 114 if (c2 == EOF) 115 ERREXIT("Premature EOF in JPEG file"); 116 return (((unsigned int) c1) << 8) + ((unsigned int) c2); 117 } 118 119 120 /* Routines to write data to output file */ 121 122 static void 123 write_1_byte (int c) 124 { 125 PUTBYTE(c); 126 } 127 128 static void 129 write_2_bytes (unsigned int val) 130 { 131 PUTBYTE((val >> 8) & 0xFF); 132 PUTBYTE(val & 0xFF); 133 } 134 135 static void 136 write_marker (int marker) 137 { 138 PUTBYTE(0xFF); 139 PUTBYTE(marker); 140 } 141 142 static void 143 copy_rest_of_file (void) 144 { 145 int c; 146 147 while ((c = NEXTBYTE()) != EOF) 148 PUTBYTE(c); 149 } 150 151 152 /* 153 * JPEG markers consist of one or more 0xFF bytes, followed by a marker 154 * code byte (which is not an FF). Here are the marker codes of interest 155 * in this program. (See jdmarker.c for a more complete list.) 156 */ 157 158 #define M_SOF0 0xC0 /* Start Of Frame N */ 159 #define M_SOF1 0xC1 /* N indicates which compression process */ 160 #define M_SOF2 0xC2 /* Only SOF0-SOF2 are now in common use */ 161 #define M_SOF3 0xC3 162 #define M_SOF5 0xC5 /* NB: codes C4 and CC are NOT SOF markers */ 163 #define M_SOF6 0xC6 164 #define M_SOF7 0xC7 165 #define M_SOF9 0xC9 166 #define M_SOF10 0xCA 167 #define M_SOF11 0xCB 168 #define M_SOF13 0xCD 169 #define M_SOF14 0xCE 170 #define M_SOF15 0xCF 171 #define M_SOI 0xD8 /* Start Of Image (beginning of datastream) */ 172 #define M_EOI 0xD9 /* End Of Image (end of datastream) */ 173 #define M_SOS 0xDA /* Start Of Scan (begins compressed data) */ 174 #define M_COM 0xFE /* COMment */ 175 176 177 /* 178 * Find the next JPEG marker and return its marker code. 179 * We expect at least one FF byte, possibly more if the compressor used FFs 180 * to pad the file. (Padding FFs will NOT be replicated in the output file.) 181 * There could also be non-FF garbage between markers. The treatment of such 182 * garbage is unspecified; we choose to skip over it but emit a warning msg. 183 * NB: this routine must not be used after seeing SOS marker, since it will 184 * not deal correctly with FF/00 sequences in the compressed image data... 185 */ 186 187 static int 188 next_marker (void) 189 { 190 int c; 191 int discarded_bytes = 0; 192 193 /* Find 0xFF byte; count and skip any non-FFs. */ 194 c = read_1_byte(); 195 while (c != 0xFF) { 196 discarded_bytes++; 197 c = read_1_byte(); 198 } 199 /* Get marker code byte, swallowing any duplicate FF bytes. Extra FFs 200 * are legal as pad bytes, so don't count them in discarded_bytes. 201 */ 202 do { 203 c = read_1_byte(); 204 } while (c == 0xFF); 205 206 if (discarded_bytes != 0) { 207 fprintf(stderr, "Warning: garbage data found in JPEG file\n"); 208 } 209 210 return c; 211 } 212 213 214 /* 215 * Read the initial marker, which should be SOI. 216 * For a JFIF file, the first two bytes of the file should be literally 217 * 0xFF M_SOI. To be more general, we could use next_marker, but if the 218 * input file weren't actually JPEG at all, next_marker might read the whole 219 * file and then return a misleading error message... 220 */ 221 222 static int 223 first_marker (void) 224 { 225 int c1, c2; 226 227 c1 = NEXTBYTE(); 228 c2 = NEXTBYTE(); 229 if (c1 != 0xFF || c2 != M_SOI) 230 ERREXIT("Not a JPEG file"); 231 return c2; 232 } 233 234 235 /* 236 * Most types of marker are followed by a variable-length parameter segment. 237 * This routine skips over the parameters for any marker we don't otherwise 238 * want to process. 239 * Note that we MUST skip the parameter segment explicitly in order not to 240 * be fooled by 0xFF bytes that might appear within the parameter segment; 241 * such bytes do NOT introduce new markers. 242 */ 243 244 static void 245 copy_variable (void) 246 /* Copy an unknown or uninteresting variable-length marker */ 247 { 248 unsigned int length; 249 250 /* Get the marker parameter length count */ 251 length = read_2_bytes(); 252 write_2_bytes(length); 253 /* Length includes itself, so must be at least 2 */ 254 if (length < 2) 255 ERREXIT("Erroneous JPEG marker length"); 256 length -= 2; 257 /* Copy the remaining bytes */ 258 while (length > 0) { 259 write_1_byte(read_1_byte()); 260 length--; 261 } 262 } 263 264 static void 265 skip_variable (void) 266 /* Skip over an unknown or uninteresting variable-length marker */ 267 { 268 unsigned int length; 269 270 /* Get the marker parameter length count */ 271 length = read_2_bytes(); 272 /* Length includes itself, so must be at least 2 */ 273 if (length < 2) 274 ERREXIT("Erroneous JPEG marker length"); 275 length -= 2; 276 /* Skip over the remaining bytes */ 277 while (length > 0) { 278 (void) read_1_byte(); 279 length--; 280 } 281 } 282 283 284 /* 285 * Parse the marker stream until SOFn or EOI is seen; 286 * copy data to output, but discard COM markers unless keep_COM is true. 287 */ 288 289 static int 290 scan_JPEG_header (int keep_COM) 291 { 292 int marker; 293 294 /* Expect SOI at start of file */ 295 if (first_marker() != M_SOI) 296 ERREXIT("Expected SOI marker first"); 297 write_marker(M_SOI); 298 299 /* Scan miscellaneous markers until we reach SOFn. */ 300 for (;;) { 301 marker = next_marker(); 302 switch (marker) { 303 /* Note that marker codes 0xC4, 0xC8, 0xCC are not, and must not be, 304 * treated as SOFn. C4 in particular is actually DHT. 305 */ 306 case M_SOF0: /* Baseline */ 307 case M_SOF1: /* Extended sequential, Huffman */ 308 case M_SOF2: /* Progressive, Huffman */ 309 case M_SOF3: /* Lossless, Huffman */ 310 case M_SOF5: /* Differential sequential, Huffman */ 311 case M_SOF6: /* Differential progressive, Huffman */ 312 case M_SOF7: /* Differential lossless, Huffman */ 313 case M_SOF9: /* Extended sequential, arithmetic */ 314 case M_SOF10: /* Progressive, arithmetic */ 315 case M_SOF11: /* Lossless, arithmetic */ 316 case M_SOF13: /* Differential sequential, arithmetic */ 317 case M_SOF14: /* Differential progressive, arithmetic */ 318 case M_SOF15: /* Differential lossless, arithmetic */ 319 return marker; 320 321 case M_SOS: /* should not see compressed data before SOF */ 322 ERREXIT("SOS without prior SOFn"); 323 break; 324 325 case M_EOI: /* in case it's a tables-only JPEG stream */ 326 return marker; 327 328 case M_COM: /* Existing COM: conditionally discard */ 329 if (keep_COM) { 330 write_marker(marker); 331 copy_variable(); 332 } else { 333 skip_variable(); 334 } 335 break; 336 337 default: /* Anything else just gets copied */ 338 write_marker(marker); 339 copy_variable(); /* we assume it has a parameter count... */ 340 break; 341 } 342 } /* end loop */ 343 } 344 345 346 /* Command line parsing code */ 347 348 static const char * progname; /* program name for error messages */ 349 350 351 static void 352 usage (void) 353 /* complain about bad command line */ 354 { 355 fprintf(stderr, "wrjpgcom inserts a textual comment in a JPEG file.\n"); 356 fprintf(stderr, "You can add to or replace any existing comment(s).\n"); 357 358 fprintf(stderr, "Usage: %s [switches] ", progname); 359 #ifdef TWO_FILE_COMMANDLINE 360 fprintf(stderr, "inputfile outputfile\n"); 361 #else 362 fprintf(stderr, "[inputfile]\n"); 363 #endif 364 365 fprintf(stderr, "Switches (names may be abbreviated):\n"); 366 fprintf(stderr, " -replace Delete any existing comments\n"); 367 fprintf(stderr, " -comment \"text\" Insert comment with given text\n"); 368 fprintf(stderr, " -cfile name Read comment from named file\n"); 369 fprintf(stderr, "Notice that you must put quotes around the comment text\n"); 370 fprintf(stderr, "when you use -comment.\n"); 371 fprintf(stderr, "If you do not give either -comment or -cfile on the command line,\n"); 372 fprintf(stderr, "then the comment text is read from standard input.\n"); 373 fprintf(stderr, "It can be multiple lines, up to %u characters total.\n", 374 (unsigned int) MAX_COM_LENGTH); 375 #ifndef TWO_FILE_COMMANDLINE 376 fprintf(stderr, "You must specify an input JPEG file name when supplying\n"); 377 fprintf(stderr, "comment text from standard input.\n"); 378 #endif 379 380 exit(EXIT_FAILURE); 381 } 382 383 384 static int 385 keymatch (char * arg, const char * keyword, int minchars) 386 /* Case-insensitive matching of (possibly abbreviated) keyword switches. */ 387 /* keyword is the constant keyword (must be lower case already), */ 388 /* minchars is length of minimum legal abbreviation. */ 389 { 390 register int ca, ck; 391 register int nmatched = 0; 392 393 while ((ca = *arg++) != '\0') { 394 if ((ck = *keyword++) == '\0') 395 return 0; /* arg longer than keyword, no good */ 396 if (isupper(ca)) /* force arg to lcase (assume ck is already) */ 397 ca = tolower(ca); 398 if (ca != ck) 399 return 0; /* no good */ 400 nmatched++; /* count matched characters */ 401 } 402 /* reached end of argument; fail if it's too short for unique abbrev */ 403 if (nmatched < minchars) 404 return 0; 405 return 1; /* A-OK */ 406 } 407 408 409 /* 410 * The main program. 411 */ 412 413 int 414 main (int argc, char **argv) 415 { 416 int argn; 417 char * arg; 418 int keep_COM = 1; 419 char * comment_arg = NULL; 420 FILE * comment_file = NULL; 421 unsigned int comment_length = 0; 422 int marker; 423 424 /* On Mac, fetch a command line. */ 425 #ifdef USE_CCOMMAND 426 argc = ccommand(&argv); 427 #endif 428 429 progname = argv[0]; 430 if (progname == NULL || progname[0] == 0) 431 progname = "wrjpgcom"; /* in case C library doesn't provide it */ 432 433 /* Parse switches, if any */ 434 for (argn = 1; argn < argc; argn++) { 435 arg = argv[argn]; 436 if (arg[0] != '-') 437 break; /* not switch, must be file name */ 438 arg++; /* advance over '-' */ 439 if (keymatch(arg, "replace", 1)) { 440 keep_COM = 0; 441 } else if (keymatch(arg, "cfile", 2)) { 442 if (++argn >= argc) usage(); 443 if ((comment_file = fopen(argv[argn], "r")) == NULL) { 444 fprintf(stderr, "%s: can't open %s\n", progname, argv[argn]); 445 exit(EXIT_FAILURE); 446 } 447 } else if (keymatch(arg, "comment", 1)) { 448 if (++argn >= argc) usage(); 449 comment_arg = argv[argn]; 450 /* If the comment text starts with '"', then we are probably running 451 * under MS-DOG and must parse out the quoted string ourselves. Sigh. 452 */ 453 if (comment_arg[0] == '"') { 454 comment_arg = (char *) malloc((size_t) MAX_COM_LENGTH); 455 if (comment_arg == NULL) 456 ERREXIT("Insufficient memory"); 457 if (strlen(argv[argn]+1) >= (size_t) MAX_COM_LENGTH) { 458 fprintf(stderr, "Comment text may not exceed %u bytes\n", 459 (unsigned int) MAX_COM_LENGTH); 460 exit(EXIT_FAILURE); 461 } 462 strcpy(comment_arg, argv[argn]+1); 463 for (;;) { 464 comment_length = (unsigned int) strlen(comment_arg); 465 if (comment_length > 0 && comment_arg[comment_length-1] == '"') { 466 comment_arg[comment_length-1] = '\0'; /* zap terminating quote */ 467 break; 468 } 469 if (++argn >= argc) 470 ERREXIT("Missing ending quote mark"); 471 if (strlen(comment_arg) + 1 + strlen(argv[argn]) >= 472 (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 strcat(comment_arg, " "); 478 strcat(comment_arg, argv[argn]); 479 } 480 } else if (strlen(comment_arg) >= (size_t) MAX_COM_LENGTH) { 481 fprintf(stderr, "Comment text may not exceed %u bytes\n", 482 (unsigned int) MAX_COM_LENGTH); 483 exit(EXIT_FAILURE); 484 } 485 comment_length = (unsigned int) strlen(comment_arg); 486 } else 487 usage(); 488 } 489 490 /* Cannot use both -comment and -cfile. */ 491 if (comment_arg != NULL && comment_file != NULL) 492 usage(); 493 /* If there is neither -comment nor -cfile, we will read the comment text 494 * from stdin; in this case there MUST be an input JPEG file name. 495 */ 496 if (comment_arg == NULL && comment_file == NULL && argn >= argc) 497 usage(); 498 499 /* Open the input file. */ 500 if (argn < argc) { 501 if ((infile = fopen(argv[argn], READ_BINARY)) == NULL) { 502 fprintf(stderr, "%s: can't open %s\n", progname, argv[argn]); 503 exit(EXIT_FAILURE); 504 } 505 } else { 506 /* default input file is stdin */ 507 #ifdef USE_SETMODE /* need to hack file mode? */ 508 setmode(fileno(stdin), O_BINARY); 509 #endif 510 #ifdef USE_FDOPEN /* need to re-open in binary mode? */ 511 if ((infile = fdopen(fileno(stdin), READ_BINARY)) == NULL) { 512 fprintf(stderr, "%s: can't open stdin\n", progname); 513 exit(EXIT_FAILURE); 514 } 515 #else 516 infile = stdin; 517 #endif 518 } 519 520 /* Open the output file. */ 521 #ifdef TWO_FILE_COMMANDLINE 522 /* Must have explicit output file name */ 523 if (argn != argc-2) { 524 fprintf(stderr, "%s: must name one input and one output file\n", 525 progname); 526 usage(); 527 } 528 if ((outfile = fopen(argv[argn+1], WRITE_BINARY)) == NULL) { 529 fprintf(stderr, "%s: can't open %s\n", progname, argv[argn+1]); 530 exit(EXIT_FAILURE); 531 } 532 #else 533 /* Unix style: expect zero or one file name */ 534 if (argn < argc-1) { 535 fprintf(stderr, "%s: only one input file\n", progname); 536 usage(); 537 } 538 /* default output file is stdout */ 539 #ifdef USE_SETMODE /* need to hack file mode? */ 540 setmode(fileno(stdout), O_BINARY); 541 #endif 542 #ifdef USE_FDOPEN /* need to re-open in binary mode? */ 543 if ((outfile = fdopen(fileno(stdout), WRITE_BINARY)) == NULL) { 544 fprintf(stderr, "%s: can't open stdout\n", progname); 545 exit(EXIT_FAILURE); 546 } 547 #else 548 outfile = stdout; 549 #endif 550 #endif /* TWO_FILE_COMMANDLINE */ 551 552 /* Collect comment text from comment_file or stdin, if necessary */ 553 if (comment_arg == NULL) { 554 FILE * src_file; 555 int c; 556 557 comment_arg = (char *) malloc((size_t) MAX_COM_LENGTH); 558 if (comment_arg == NULL) 559 ERREXIT("Insufficient memory"); 560 comment_length = 0; 561 src_file = (comment_file != NULL ? comment_file : stdin); 562 while ((c = getc(src_file)) != EOF) { 563 if (comment_length >= (unsigned int) MAX_COM_LENGTH) { 564 fprintf(stderr, "Comment text may not exceed %u bytes\n", 565 (unsigned int) MAX_COM_LENGTH); 566 exit(EXIT_FAILURE); 567 } 568 comment_arg[comment_length++] = (char) c; 569 } 570 if (comment_file != NULL) 571 fclose(comment_file); 572 } 573 574 /* Copy JPEG headers until SOFn marker; 575 * we will insert the new comment marker just before SOFn. 576 * This (a) causes the new comment to appear after, rather than before, 577 * existing comments; and (b) ensures that comments come after any JFIF 578 * or JFXX markers, as required by the JFIF specification. 579 */ 580 marker = scan_JPEG_header(keep_COM); 581 /* Insert the new COM marker, but only if nonempty text has been supplied */ 582 if (comment_length > 0) { 583 write_marker(M_COM); 584 write_2_bytes(comment_length + 2); 585 while (comment_length > 0) { 586 write_1_byte(*comment_arg++); 587 comment_length--; 588 } 589 } 590 /* Duplicate the remainder of the source file. 591 * Note that any COM markers occuring after SOF will not be touched. 592 */ 593 write_marker(marker); 594 copy_rest_of_file(); 595 596 /* All done. */ 597 exit(EXIT_SUCCESS); 598 return 0; /* suppress no-return-value warnings */ 599 } 600