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.ijg 9 * file. 10 * 11 * This file contains a very simple stand-alone application that inserts 12 * user-supplied text as a COM (comment) marker in a JFIF file. 13 * This may be useful as an example of the minimum logic needed to parse 14 * JPEG markers. 15 */ 16 17 #define JPEG_CJPEG_DJPEG /* to get the command-line config symbols */ 18 #include "jinclude.h" /* get auto-config symbols, <stdio.h> */ 19 20 #ifndef HAVE_STDLIB_H /* <stdlib.h> should declare malloc() */ 21 extern void *malloc (); 22 #endif 23 #include <ctype.h> /* to declare isupper(), tolower() */ 24 #ifdef USE_SETMODE 25 #include <fcntl.h> /* to declare setmode()'s parameter macros */ 26 /* If you have setmode() but not <io.h>, just delete this line: */ 27 #include <io.h> /* to declare setmode() */ 28 #endif 29 30 #ifdef USE_CCOMMAND /* command-line reader for Macintosh */ 31 #ifdef __MWERKS__ 32 #include <SIOUX.h> /* Metrowerks needs this */ 33 #include <console.h> /* ... and this */ 34 #endif 35 #ifdef THINK_C 36 #include <console.h> /* Think declares it here */ 37 #endif 38 #endif 39 40 #ifdef DONT_USE_B_MODE /* define mode parameters for fopen() */ 41 #define READ_BINARY "r" 42 #define WRITE_BINARY "w" 43 #else 44 #define READ_BINARY "rb" 45 #define WRITE_BINARY "wb" 46 #endif 47 48 #ifndef EXIT_FAILURE /* define exit() codes if not provided */ 49 #define EXIT_FAILURE 1 50 #endif 51 #ifndef EXIT_SUCCESS 52 #define EXIT_SUCCESS 0 53 #endif 54 55 /* Reduce this value if your malloc() can't allocate blocks up to 64K. 56 * On DOS, compiling in large model is usually a better solution. 57 */ 58 59 #ifndef MAX_COM_LENGTH 60 #define MAX_COM_LENGTH 65000L /* must be <= 65533 in any case */ 61 #endif 62 63 64 /* 65 * These macros are used to read the input file and write the output file. 66 * To reuse this code in another application, you might need to change these. 67 */ 68 69 static FILE *infile; /* input JPEG file */ 70 71 /* Return next input byte, or EOF if no more */ 72 #define NEXTBYTE() getc(infile) 73 74 static FILE *outfile; /* output JPEG file */ 75 76 /* Emit an output byte */ 77 #define PUTBYTE(x) putc((x), outfile) 78 79 80 /* Error exit handler */ 81 #define ERREXIT(msg) (fprintf(stderr, "%s\n", msg), exit(EXIT_FAILURE)) 82 83 84 /* Read one byte, testing for EOF */ 85 static int 86 read_1_byte (void) 87 { 88 int c; 89 90 c = NEXTBYTE(); 91 if (c == EOF) 92 ERREXIT("Premature EOF in JPEG file"); 93 return c; 94 } 95 96 /* Read 2 bytes, convert to unsigned int */ 97 /* All 2-byte quantities in JPEG markers are MSB first */ 98 static unsigned int 99 read_2_bytes (void) 100 { 101 int c1, c2; 102 103 c1 = NEXTBYTE(); 104 if (c1 == EOF) 105 ERREXIT("Premature EOF in JPEG file"); 106 c2 = NEXTBYTE(); 107 if (c2 == EOF) 108 ERREXIT("Premature EOF in JPEG file"); 109 return (((unsigned int) c1) << 8) + ((unsigned int) c2); 110 } 111 112 113 /* Routines to write data to output file */ 114 115 static void 116 write_1_byte (int c) 117 { 118 PUTBYTE(c); 119 } 120 121 static void 122 write_2_bytes (unsigned int val) 123 { 124 PUTBYTE((val >> 8) & 0xFF); 125 PUTBYTE(val & 0xFF); 126 } 127 128 static void 129 write_marker (int marker) 130 { 131 PUTBYTE(0xFF); 132 PUTBYTE(marker); 133 } 134 135 static void 136 copy_rest_of_file (void) 137 { 138 int c; 139 140 while ((c = NEXTBYTE()) != EOF) 141 PUTBYTE(c); 142 } 143 144 145 /* 146 * JPEG markers consist of one or more 0xFF bytes, followed by a marker 147 * code byte (which is not an FF). Here are the marker codes of interest 148 * in this program. (See jdmarker.c for a more complete list.) 149 */ 150 151 #define M_SOF0 0xC0 /* Start Of Frame N */ 152 #define M_SOF1 0xC1 /* N indicates which compression process */ 153 #define M_SOF2 0xC2 /* Only SOF0-SOF2 are now in common use */ 154 #define M_SOF3 0xC3 155 #define M_SOF5 0xC5 /* NB: codes C4 and CC are NOT SOF markers */ 156 #define M_SOF6 0xC6 157 #define M_SOF7 0xC7 158 #define M_SOF9 0xC9 159 #define M_SOF10 0xCA 160 #define M_SOF11 0xCB 161 #define M_SOF13 0xCD 162 #define M_SOF14 0xCE 163 #define M_SOF15 0xCF 164 #define M_SOI 0xD8 /* Start Of Image (beginning of datastream) */ 165 #define M_EOI 0xD9 /* End Of Image (end of datastream) */ 166 #define M_SOS 0xDA /* Start Of Scan (begins compressed data) */ 167 #define M_COM 0xFE /* COMment */ 168 169 170 /* 171 * Find the next JPEG marker and return its marker code. 172 * We expect at least one FF byte, possibly more if the compressor used FFs 173 * to pad the file. (Padding FFs will NOT be replicated in the output file.) 174 * There could also be non-FF garbage between markers. The treatment of such 175 * garbage is unspecified; we choose to skip over it but emit a warning msg. 176 * NB: this routine must not be used after seeing SOS marker, since it will 177 * not deal correctly with FF/00 sequences in the compressed image data... 178 */ 179 180 static int 181 next_marker (void) 182 { 183 int c; 184 int discarded_bytes = 0; 185 186 /* Find 0xFF byte; count and skip any non-FFs. */ 187 c = read_1_byte(); 188 while (c != 0xFF) { 189 discarded_bytes++; 190 c = read_1_byte(); 191 } 192 /* Get marker code byte, swallowing any duplicate FF bytes. Extra FFs 193 * are legal as pad bytes, so don't count them in discarded_bytes. 194 */ 195 do { 196 c = read_1_byte(); 197 } while (c == 0xFF); 198 199 if (discarded_bytes != 0) { 200 fprintf(stderr, "Warning: garbage data found in JPEG file\n"); 201 } 202 203 return c; 204 } 205 206 207 /* 208 * Read the initial marker, which should be SOI. 209 * For a JFIF file, the first two bytes of the file should be literally 210 * 0xFF M_SOI. To be more general, we could use next_marker, but if the 211 * input file weren't actually JPEG at all, next_marker might read the whole 212 * file and then return a misleading error message... 213 */ 214 215 static int 216 first_marker (void) 217 { 218 int c1, c2; 219 220 c1 = NEXTBYTE(); 221 c2 = NEXTBYTE(); 222 if (c1 != 0xFF || c2 != M_SOI) 223 ERREXIT("Not a JPEG file"); 224 return c2; 225 } 226 227 228 /* 229 * Most types of marker are followed by a variable-length parameter segment. 230 * This routine skips over the parameters for any marker we don't otherwise 231 * want to process. 232 * Note that we MUST skip the parameter segment explicitly in order not to 233 * be fooled by 0xFF bytes that might appear within the parameter segment; 234 * such bytes do NOT introduce new markers. 235 */ 236 237 static void 238 copy_variable (void) 239 /* Copy an unknown or uninteresting variable-length marker */ 240 { 241 unsigned int length; 242 243 /* Get the marker parameter length count */ 244 length = read_2_bytes(); 245 write_2_bytes(length); 246 /* Length includes itself, so must be at least 2 */ 247 if (length < 2) 248 ERREXIT("Erroneous JPEG marker length"); 249 length -= 2; 250 /* Copy the remaining bytes */ 251 while (length > 0) { 252 write_1_byte(read_1_byte()); 253 length--; 254 } 255 } 256 257 static void 258 skip_variable (void) 259 /* Skip over an unknown or uninteresting variable-length marker */ 260 { 261 unsigned int length; 262 263 /* Get the marker parameter length count */ 264 length = read_2_bytes(); 265 /* Length includes itself, so must be at least 2 */ 266 if (length < 2) 267 ERREXIT("Erroneous JPEG marker length"); 268 length -= 2; 269 /* Skip over the remaining bytes */ 270 while (length > 0) { 271 (void) read_1_byte(); 272 length--; 273 } 274 } 275 276 277 /* 278 * Parse the marker stream until SOFn or EOI is seen; 279 * copy data to output, but discard COM markers unless keep_COM is true. 280 */ 281 282 static int 283 scan_JPEG_header (int keep_COM) 284 { 285 int marker; 286 287 /* Expect SOI at start of file */ 288 if (first_marker() != M_SOI) 289 ERREXIT("Expected SOI marker first"); 290 write_marker(M_SOI); 291 292 /* Scan miscellaneous markers until we reach SOFn. */ 293 for (;;) { 294 marker = next_marker(); 295 switch (marker) { 296 /* Note that marker codes 0xC4, 0xC8, 0xCC are not, and must not be, 297 * treated as SOFn. C4 in particular is actually DHT. 298 */ 299 case M_SOF0: /* Baseline */ 300 case M_SOF1: /* Extended sequential, Huffman */ 301 case M_SOF2: /* Progressive, Huffman */ 302 case M_SOF3: /* Lossless, Huffman */ 303 case M_SOF5: /* Differential sequential, Huffman */ 304 case M_SOF6: /* Differential progressive, Huffman */ 305 case M_SOF7: /* Differential lossless, Huffman */ 306 case M_SOF9: /* Extended sequential, arithmetic */ 307 case M_SOF10: /* Progressive, arithmetic */ 308 case M_SOF11: /* Lossless, arithmetic */ 309 case M_SOF13: /* Differential sequential, arithmetic */ 310 case M_SOF14: /* Differential progressive, arithmetic */ 311 case M_SOF15: /* Differential lossless, arithmetic */ 312 return marker; 313 314 case M_SOS: /* should not see compressed data before SOF */ 315 ERREXIT("SOS without prior SOFn"); 316 break; 317 318 case M_EOI: /* in case it's a tables-only JPEG stream */ 319 return marker; 320 321 case M_COM: /* Existing COM: conditionally discard */ 322 if (keep_COM) { 323 write_marker(marker); 324 copy_variable(); 325 } else { 326 skip_variable(); 327 } 328 break; 329 330 default: /* Anything else just gets copied */ 331 write_marker(marker); 332 copy_variable(); /* we assume it has a parameter count... */ 333 break; 334 } 335 } /* end loop */ 336 } 337 338 339 /* Command line parsing code */ 340 341 static const char *progname; /* program name for error messages */ 342 343 344 static void 345 usage (void) 346 /* complain about bad command line */ 347 { 348 fprintf(stderr, "wrjpgcom inserts a textual comment in a JPEG file.\n"); 349 fprintf(stderr, "You can add to or replace any existing comment(s).\n"); 350 351 fprintf(stderr, "Usage: %s [switches] ", progname); 352 #ifdef TWO_FILE_COMMANDLINE 353 fprintf(stderr, "inputfile outputfile\n"); 354 #else 355 fprintf(stderr, "[inputfile]\n"); 356 #endif 357 358 fprintf(stderr, "Switches (names may be abbreviated):\n"); 359 fprintf(stderr, " -replace Delete any existing comments\n"); 360 fprintf(stderr, " -comment \"text\" Insert comment with given text\n"); 361 fprintf(stderr, " -cfile name Read comment from named file\n"); 362 fprintf(stderr, "Notice that you must put quotes around the comment text\n"); 363 fprintf(stderr, "when you use -comment.\n"); 364 fprintf(stderr, "If you do not give either -comment or -cfile on the command line,\n"); 365 fprintf(stderr, "then the comment text is read from standard input.\n"); 366 fprintf(stderr, "It can be multiple lines, up to %u characters total.\n", 367 (unsigned int) MAX_COM_LENGTH); 368 #ifndef TWO_FILE_COMMANDLINE 369 fprintf(stderr, "You must specify an input JPEG file name when supplying\n"); 370 fprintf(stderr, "comment text from standard input.\n"); 371 #endif 372 373 exit(EXIT_FAILURE); 374 } 375 376 377 static int 378 keymatch (char *arg, const char *keyword, int minchars) 379 /* Case-insensitive matching of (possibly abbreviated) keyword switches. */ 380 /* keyword is the constant keyword (must be lower case already), */ 381 /* minchars is length of minimum legal abbreviation. */ 382 { 383 register int ca, ck; 384 register int nmatched = 0; 385 386 while ((ca = *arg++) != '\0') { 387 if ((ck = *keyword++) == '\0') 388 return 0; /* arg longer than keyword, no good */ 389 if (isupper(ca)) /* force arg to lcase (assume ck is already) */ 390 ca = tolower(ca); 391 if (ca != ck) 392 return 0; /* no good */ 393 nmatched++; /* count matched characters */ 394 } 395 /* reached end of argument; fail if it's too short for unique abbrev */ 396 if (nmatched < minchars) 397 return 0; 398 return 1; /* A-OK */ 399 } 400 401 402 /* 403 * The main program. 404 */ 405 406 int 407 main (int argc, char **argv) 408 { 409 int argn; 410 char *arg; 411 int keep_COM = 1; 412 char *comment_arg = NULL; 413 FILE *comment_file = NULL; 414 unsigned int comment_length = 0; 415 int marker; 416 417 /* On Mac, fetch a command line. */ 418 #ifdef USE_CCOMMAND 419 argc = ccommand(&argv); 420 #endif 421 422 progname = argv[0]; 423 if (progname == NULL || progname[0] == 0) 424 progname = "wrjpgcom"; /* in case C library doesn't provide it */ 425 426 /* Parse switches, if any */ 427 for (argn = 1; argn < argc; argn++) { 428 arg = argv[argn]; 429 if (arg[0] != '-') 430 break; /* not switch, must be file name */ 431 arg++; /* advance over '-' */ 432 if (keymatch(arg, "replace", 1)) { 433 keep_COM = 0; 434 } else if (keymatch(arg, "cfile", 2)) { 435 if (++argn >= argc) usage(); 436 if ((comment_file = fopen(argv[argn], "r")) == NULL) { 437 fprintf(stderr, "%s: can't open %s\n", progname, argv[argn]); 438 exit(EXIT_FAILURE); 439 } 440 } else if (keymatch(arg, "comment", 1)) { 441 if (++argn >= argc) usage(); 442 comment_arg = argv[argn]; 443 /* If the comment text starts with '"', then we are probably running 444 * under MS-DOG and must parse out the quoted string ourselves. Sigh. 445 */ 446 if (comment_arg[0] == '"') { 447 comment_arg = (char *) malloc((size_t) MAX_COM_LENGTH); 448 if (comment_arg == NULL) 449 ERREXIT("Insufficient memory"); 450 if (strlen(argv[argn]) + 2 >= (size_t) MAX_COM_LENGTH) { 451 fprintf(stderr, "Comment text may not exceed %u bytes\n", 452 (unsigned int) MAX_COM_LENGTH); 453 exit(EXIT_FAILURE); 454 } 455 strcpy(comment_arg, argv[argn]+1); 456 for (;;) { 457 comment_length = (unsigned int) strlen(comment_arg); 458 if (comment_length > 0 && comment_arg[comment_length-1] == '"') { 459 comment_arg[comment_length-1] = '\0'; /* zap terminating quote */ 460 break; 461 } 462 if (++argn >= argc) 463 ERREXIT("Missing ending quote mark"); 464 if (strlen(comment_arg) + strlen(argv[argn]) + 2 >= 465 (size_t) MAX_COM_LENGTH) { 466 fprintf(stderr, "Comment text may not exceed %u bytes\n", 467 (unsigned int) MAX_COM_LENGTH); 468 exit(EXIT_FAILURE); 469 } 470 strcat(comment_arg, " "); 471 strcat(comment_arg, argv[argn]); 472 } 473 } else if (strlen(argv[argn]) >= (size_t) MAX_COM_LENGTH) { 474 fprintf(stderr, "Comment text may not exceed %u bytes\n", 475 (unsigned int) MAX_COM_LENGTH); 476 exit(EXIT_FAILURE); 477 } 478 comment_length = (unsigned int) strlen(comment_arg); 479 } else 480 usage(); 481 } 482 483 /* Cannot use both -comment and -cfile. */ 484 if (comment_arg != NULL && comment_file != NULL) 485 usage(); 486 /* If there is neither -comment nor -cfile, we will read the comment text 487 * from stdin; in this case there MUST be an input JPEG file name. 488 */ 489 if (comment_arg == NULL && comment_file == NULL && argn >= argc) 490 usage(); 491 492 /* Open the input file. */ 493 if (argn < argc) { 494 if ((infile = fopen(argv[argn], READ_BINARY)) == NULL) { 495 fprintf(stderr, "%s: can't open %s\n", progname, argv[argn]); 496 exit(EXIT_FAILURE); 497 } 498 } else { 499 /* default input file is stdin */ 500 #ifdef USE_SETMODE /* need to hack file mode? */ 501 setmode(fileno(stdin), O_BINARY); 502 #endif 503 #ifdef USE_FDOPEN /* need to re-open in binary mode? */ 504 if ((infile = fdopen(fileno(stdin), READ_BINARY)) == NULL) { 505 fprintf(stderr, "%s: can't open stdin\n", progname); 506 exit(EXIT_FAILURE); 507 } 508 #else 509 infile = stdin; 510 #endif 511 } 512 513 /* Open the output file. */ 514 #ifdef TWO_FILE_COMMANDLINE 515 /* Must have explicit output file name */ 516 if (argn != argc-2) { 517 fprintf(stderr, "%s: must name one input and one output file\n", 518 progname); 519 usage(); 520 } 521 if ((outfile = fopen(argv[argn+1], WRITE_BINARY)) == NULL) { 522 fprintf(stderr, "%s: can't open %s\n", progname, argv[argn+1]); 523 exit(EXIT_FAILURE); 524 } 525 #else 526 /* Unix style: expect zero or one file name */ 527 if (argn < argc-1) { 528 fprintf(stderr, "%s: only one input file\n", progname); 529 usage(); 530 } 531 /* default output file is stdout */ 532 #ifdef USE_SETMODE /* need to hack file mode? */ 533 setmode(fileno(stdout), O_BINARY); 534 #endif 535 #ifdef USE_FDOPEN /* need to re-open in binary mode? */ 536 if ((outfile = fdopen(fileno(stdout), WRITE_BINARY)) == NULL) { 537 fprintf(stderr, "%s: can't open stdout\n", progname); 538 exit(EXIT_FAILURE); 539 } 540 #else 541 outfile = stdout; 542 #endif 543 #endif /* TWO_FILE_COMMANDLINE */ 544 545 /* Collect comment text from comment_file or stdin, if necessary */ 546 if (comment_arg == NULL) { 547 FILE *src_file; 548 int c; 549 550 comment_arg = (char *) malloc((size_t) MAX_COM_LENGTH); 551 if (comment_arg == NULL) 552 ERREXIT("Insufficient memory"); 553 comment_length = 0; 554 src_file = (comment_file != NULL ? comment_file : stdin); 555 while ((c = getc(src_file)) != EOF) { 556 if (comment_length >= (unsigned int) MAX_COM_LENGTH) { 557 fprintf(stderr, "Comment text may not exceed %u bytes\n", 558 (unsigned int) MAX_COM_LENGTH); 559 exit(EXIT_FAILURE); 560 } 561 comment_arg[comment_length++] = (char) c; 562 } 563 if (comment_file != NULL) 564 fclose(comment_file); 565 } 566 567 /* Copy JPEG headers until SOFn marker; 568 * we will insert the new comment marker just before SOFn. 569 * This (a) causes the new comment to appear after, rather than before, 570 * existing comments; and (b) ensures that comments come after any JFIF 571 * or JFXX markers, as required by the JFIF specification. 572 */ 573 marker = scan_JPEG_header(keep_COM); 574 /* Insert the new COM marker, but only if nonempty text has been supplied */ 575 if (comment_length > 0) { 576 write_marker(M_COM); 577 write_2_bytes(comment_length + 2); 578 while (comment_length > 0) { 579 write_1_byte(*comment_arg++); 580 comment_length--; 581 } 582 } 583 /* Duplicate the remainder of the source file. 584 * Note that any COM markers occuring after SOF will not be touched. 585 */ 586 write_marker(marker); 587 copy_rest_of_file(); 588 589 /* All done. */ 590 exit(EXIT_SUCCESS); 591 return 0; /* suppress no-return-value warnings */ 592 } 593