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