workbench/libs/jpeg/rdjpgcom.c

   1 /*
   2  * rdjpgcom.c
   3  *
   4  * Copyright (C) 1994-1997, Thomas G. Lane.
   5  * Modified 2009 by Bill Allombert, 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 displays
  10  * the text in COM (comment) markers 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 #ifdef HAVE_LOCALE_H
  19 #include <locale.h>             /* Bill Allombert: use locale for isprint */
  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 #else
  41 #ifdef VMS                      /* VMS is very nonstandard */
  42 #define READ_BINARY     "rb", "ctx=stm"
  43 #else                           /* standard ANSI-compliant case */
  44 #define READ_BINARY     "rb"
  45 #endif
  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 #ifdef VMS
  53 #define EXIT_SUCCESS  1         /* VMS is very nonstandard */
  54 #else
  55 #define EXIT_SUCCESS  0
  56 #endif
  57 #endif
  58
  59
  60 /*
  61  * These macros are used to read the input file.
  62  * To reuse this code in another application, you might need to change these.
  63  */
  64
  65 static FILE * infile;           /* input JPEG file */
  66
  67 /* Return next input byte, or EOF if no more */
  68 #define NEXTBYTE()  getc(infile)
  69
  70
  71 /* Error exit handler */
  72 #define ERREXIT(msg)  (fprintf(stderr, "%s\n", msg), exit(EXIT_FAILURE))
  73
  74
  75 /* Read one byte, testing for EOF */
  76 static int
  77 read_1_byte (void)
  78 {
  79   int c;
  80
  81   c = NEXTBYTE();
  82   if (c == EOF)
  83     ERREXIT("Premature EOF in JPEG file");
  84   return c;
  85 }
  86
  87 /* Read 2 bytes, convert to unsigned int */
  88 /* All 2-byte quantities in JPEG markers are MSB first */
  89 static unsigned int
  90 read_2_bytes (void)
  91 {
  92   int c1, c2;
  93
  94   c1 = NEXTBYTE();
  95   if (c1 == EOF)
  96     ERREXIT("Premature EOF in JPEG file");
  97   c2 = NEXTBYTE();
  98   if (c2 == EOF)
  99     ERREXIT("Premature EOF in JPEG file");
 100   return (((unsigned int) c1) << 8) + ((unsigned int) c2);
 101 }
 102
 103
 104 /*
 105  * JPEG markers consist of one or more 0xFF bytes, followed by a marker
 106  * code byte (which is not an FF).  Here are the marker codes of interest
 107  * in this program.  (See jdmarker.c for a more complete list.)
 108  */
 109
 110 #define M_SOF0  0xC0            /* Start Of Frame N */
 111 #define M_SOF1  0xC1            /* N indicates which compression process */
 112 #define M_SOF2  0xC2            /* Only SOF0-SOF2 are now in common use */
 113 #define M_SOF3  0xC3
 114 #define M_SOF5  0xC5            /* NB: codes C4 and CC are NOT SOF markers */
 115 #define M_SOF6  0xC6
 116 #define M_SOF7  0xC7
 117 #define M_SOF9  0xC9
 118 #define M_SOF10 0xCA
 119 #define M_SOF11 0xCB
 120 #define M_SOF13 0xCD
 121 #define M_SOF14 0xCE
 122 #define M_SOF15 0xCF
 123 #define M_SOI   0xD8            /* Start Of Image (beginning of datastream) */
 124 #define M_EOI   0xD9            /* End Of Image (end of datastream) */
 125 #define M_SOS   0xDA            /* Start Of Scan (begins compressed data) */
 126 #define M_APP0  0xE0            /* Application-specific marker, type N */
 127 #define M_APP12 0xEC            /* (we don't bother to list all 16 APPn's) */
 128 #define M_COM   0xFE            /* COMment */
 129
 130
 131 /*
 132  * Find the next JPEG marker and return its marker code.
 133  * We expect at least one FF byte, possibly more if the compressor used FFs
 134  * to pad the file.
 135  * There could also be non-FF garbage between markers.  The treatment of such
 136  * garbage is unspecified; we choose to skip over it but emit a warning msg.
 137  * NB: this routine must not be used after seeing SOS marker, since it will
 138  * not deal correctly with FF/00 sequences in the compressed image data...
 139  */
 140
 141 static int
 142 next_marker (void)
 143 {
 144   int c;
 145   int discarded_bytes = 0;
 146
 147   /* Find 0xFF byte; count and skip any non-FFs. */
 148   c = read_1_byte();
 149   while (c != 0xFF) {
 150     discarded_bytes++;
 151     c = read_1_byte();
 152   }
 153   /* Get marker code byte, swallowing any duplicate FF bytes.  Extra FFs
 154    * are legal as pad bytes, so don't count them in discarded_bytes.
 155    */
 156   do {
 157     c = read_1_byte();
 158   } while (c == 0xFF);
 159
 160   if (discarded_bytes != 0) {
 161     fprintf(stderr, "Warning: garbage data found in JPEG file\n");
 162   }
 163
 164   return c;
 165 }
 166
 167
 168 /*
 169  * Read the initial marker, which should be SOI.
 170  * For a JFIF file, the first two bytes of the file should be literally
 171  * 0xFF M_SOI.  To be more general, we could use next_marker, but if the
 172  * input file weren't actually JPEG at all, next_marker might read the whole
 173  * file and then return a misleading error message...
 174  */
 175
 176 static int
 177 first_marker (void)
 178 {
 179   int c1, c2;
 180
 181   c1 = NEXTBYTE();
 182   c2 = NEXTBYTE();
 183   if (c1 != 0xFF || c2 != M_SOI)
 184     ERREXIT("Not a JPEG file");
 185   return c2;
 186 }
 187
 188
 189 /*
 190  * Most types of marker are followed by a variable-length parameter segment.
 191  * This routine skips over the parameters for any marker we don't otherwise
 192  * want to process.
 193  * Note that we MUST skip the parameter segment explicitly in order not to
 194  * be fooled by 0xFF bytes that might appear within the parameter segment;
 195  * such bytes do NOT introduce new markers.
 196  */
 197
 198 static void
 199 skip_variable (void)
 200 /* Skip over an unknown or uninteresting variable-length marker */
 201 {
 202   unsigned int length;
 203
 204   /* Get the marker parameter length count */
 205   length = read_2_bytes();
 206   /* Length includes itself, so must be at least 2 */
 207   if (length < 2)
 208     ERREXIT("Erroneous JPEG marker length");
 209   length -= 2;
 210   /* Skip over the remaining bytes */
 211   while (length > 0) {
 212     (void) read_1_byte();
 213     length--;
 214   }
 215 }
 216
 217
 218 /*
 219  * Process a COM marker.
 220  * We want to print out the marker contents as legible text;
 221  * we must guard against non-text junk and varying newline representations.
 222  */
 223
 224 static void
 225 process_COM (int raw)
 226 {
 227   unsigned int length;
 228   int ch;
 229   int lastch = 0;
 230
 231   /* Bill Allombert: set locale properly for isprint */
 232 #ifdef HAVE_LOCALE_H
 233   setlocale(LC_CTYPE, "");
 234 #endif
 235
 236   /* Get the marker parameter length count */
 237   length = read_2_bytes();
 238   /* Length includes itself, so must be at least 2 */
 239   if (length < 2)
 240     ERREXIT("Erroneous JPEG marker length");
 241   length -= 2;
 242
 243   while (length > 0) {
 244     ch = read_1_byte();
 245     if (raw) {
 246       putc(ch, stdout);
 247     /* Emit the character in a readable form.
 248      * Nonprintables are converted to \nnn form,
 249      * while \ is converted to \\.
 250      * Newlines in CR, CR/LF, or LF form will be printed as one newline.
 251      */
 252     } else if (ch == '\r') {
 253       printf("\n");
 254     } else if (ch == '\n') {
 255       if (lastch != '\r')
 256         printf("\n");
 257     } else if (ch == '\\') {
 258       printf("\\\\");
 259     } else if (isprint(ch)) {
 260       putc(ch, stdout);
 261     } else {
 262       printf("\\%03o", ch);
 263     }
 264     lastch = ch;
 265     length--;
 266   }
 267   printf("\n");
 268
 269   /* Bill Allombert: revert to C locale */
 270 #ifdef HAVE_LOCALE_H
 271   setlocale(LC_CTYPE, "C");
 272 #endif
 273 }
 274
 275
 276 /*
 277  * Process a SOFn marker.
 278  * This code is only needed if you want to know the image dimensions...
 279  */
 280
 281 static void
 282 process_SOFn (int marker)
 283 {
 284   unsigned int length;
 285   unsigned int image_height, image_width;
 286   int data_precision, num_components;
 287   const char * process;
 288   int ci;
 289
 290   length = read_2_bytes();      /* usual parameter length count */
 291
 292   data_precision = read_1_byte();
 293   image_height = read_2_bytes();
 294   image_width = read_2_bytes();
 295   num_components = read_1_byte();
 296
 297   switch (marker) {
 298   case M_SOF0:  process = "Baseline";  break;
 299   case M_SOF1:  process = "Extended sequential";  break;
 300   case M_SOF2:  process = "Progressive";  break;
 301   case M_SOF3:  process = "Lossless";  break;
 302   case M_SOF5:  process = "Differential sequential";  break;
 303   case M_SOF6:  process = "Differential progressive";  break;
 304   case M_SOF7:  process = "Differential lossless";  break;
 305   case M_SOF9:  process = "Extended sequential, arithmetic coding";  break;
 306   case M_SOF10: process = "Progressive, arithmetic coding";  break;
 307   case M_SOF11: process = "Lossless, arithmetic coding";  break;
 308   case M_SOF13: process = "Differential sequential, arithmetic coding";  break;
 309   case M_SOF14: process = "Differential progressive, arithmetic coding"; break;
 310   case M_SOF15: process = "Differential lossless, arithmetic coding";  break;
 311   default:      process = "Unknown";  break;
 312   }
 313
 314   printf("JPEG image is %uw * %uh, %d color components, %d bits per sample\n",
 315          image_width, image_height, num_components, data_precision);
 316   printf("JPEG process: %s\n", process);
 317
 318   if (length != (unsigned int) (8 + num_components * 3))
 319     ERREXIT("Bogus SOF marker length");
 320
 321   for (ci = 0; ci < num_components; ci++) {
 322     (void) read_1_byte();       /* Component ID code */
 323     (void) read_1_byte();       /* H, V sampling factors */
 324     (void) read_1_byte();       /* Quantization table number */
 325   }
 326 }
 327
 328
 329 /*
 330  * Parse the marker stream until SOS or EOI is seen;
 331  * display any COM markers.
 332  * While the companion program wrjpgcom will always insert COM markers before
 333  * SOFn, other implementations might not, so we scan to SOS before stopping.
 334  * If we were only interested in the image dimensions, we would stop at SOFn.
 335  * (Conversely, if we only cared about COM markers, there would be no need
 336  * for special code to handle SOFn; we could treat it like other markers.)
 337  */
 338
 339 static int
 340 scan_JPEG_header (int verbose, int raw)
 341 {
 342   int marker;
 343
 344   /* Expect SOI at start of file */
 345   if (first_marker() != M_SOI)
 346     ERREXIT("Expected SOI marker first");
 347
 348   /* Scan miscellaneous markers until we reach SOS. */
 349   for (;;) {
 350     marker = next_marker();
 351     switch (marker) {
 352       /* Note that marker codes 0xC4, 0xC8, 0xCC are not, and must not be,
 353        * treated as SOFn.  C4 in particular is actually DHT.
 354        */
 355     case M_SOF0:                /* Baseline */
 356     case M_SOF1:                /* Extended sequential, Huffman */
 357     case M_SOF2:                /* Progressive, Huffman */
 358     case M_SOF3:                /* Lossless, Huffman */
 359     case M_SOF5:                /* Differential sequential, Huffman */
 360     case M_SOF6:                /* Differential progressive, Huffman */
 361     case M_SOF7:                /* Differential lossless, Huffman */
 362     case M_SOF9:                /* Extended sequential, arithmetic */
 363     case M_SOF10:               /* Progressive, arithmetic */
 364     case M_SOF11:               /* Lossless, arithmetic */
 365     case M_SOF13:               /* Differential sequential, arithmetic */
 366     case M_SOF14:               /* Differential progressive, arithmetic */
 367     case M_SOF15:               /* Differential lossless, arithmetic */
 368       if (verbose)
 369         process_SOFn(marker);
 370       else
 371         skip_variable();
 372       break;
 373
 374     case M_SOS:                 /* stop before hitting compressed data */
 375       return marker;
 376
 377     case M_EOI:                 /* in case it's a tables-only JPEG stream */
 378       return marker;
 379
 380     case M_COM:
 381       process_COM(raw);
 382       break;
 383
 384     case M_APP12:
 385       /* Some digital camera makers put useful textual information into
 386        * APP12 markers, so we print those out too when in -verbose mode.
 387        */
 388       if (verbose) {
 389         printf("APP12 contains:\n");
 390         process_COM(raw);
 391       } else
 392         skip_variable();
 393       break;
 394
 395     default:                    /* Anything else just gets skipped */
 396       skip_variable();          /* we assume it has a parameter count... */
 397       break;
 398     }
 399   } /* end loop */
 400 }
 401
 402
 403 /* Command line parsing code */
 404
 405 static const char * progname;   /* program name for error messages */
 406
 407
 408 static void
 409 usage (void)
 410 /* complain about bad command line */
 411 {
 412   fprintf(stderr, "rdjpgcom displays any textual comments in a JPEG file.\n");
 413
 414   fprintf(stderr, "Usage: %s [switches] [inputfile]\n", progname);
 415
 416   fprintf(stderr, "Switches (names may be abbreviated):\n");
 417   fprintf(stderr, "  -raw        Display non-printable characters in comments (unsafe)\n");
 418   fprintf(stderr, "  -verbose    Also display dimensions of JPEG image\n");
 419
 420   exit(EXIT_FAILURE);
 421 }
 422
 423
 424 static int
 425 keymatch (char * arg, const char * keyword, int minchars)
 426 /* Case-insensitive matching of (possibly abbreviated) keyword switches. */
 427 /* keyword is the constant keyword (must be lower case already), */
 428 /* minchars is length of minimum legal abbreviation. */
 429 {
 430   register int ca, ck;
 431   register int nmatched = 0;
 432
 433   while ((ca = *arg++) != '\0') {
 434     if ((ck = *keyword++) == '\0')
 435       return 0;                 /* arg longer than keyword, no good */
 436     if (isupper(ca))            /* force arg to lcase (assume ck is already) */
 437       ca = tolower(ca);
 438     if (ca != ck)
 439       return 0;                 /* no good */
 440     nmatched++;                 /* count matched characters */
 441   }
 442   /* reached end of argument; fail if it's too short for unique abbrev */
 443   if (nmatched < minchars)
 444     return 0;
 445   return 1;                     /* A-OK */
 446 }
 447
 448
 449 /*
 450  * The main program.
 451  */
 452
 453 int
 454 main (int argc, char **argv)
 455 {
 456   int argn;
 457   char * arg;
 458   int verbose = 0, raw = 0;
 459
 460   /* On Mac, fetch a command line. */
 461 #ifdef USE_CCOMMAND
 462   argc = ccommand(&argv);
 463 #endif
 464
 465   progname = argv[0];
 466   if (progname == NULL || progname[0] == 0)
 467     progname = "rdjpgcom";      /* in case C library doesn't provide it */
 468
 469   /* Parse switches, if any */
 470   for (argn = 1; argn < argc; argn++) {
 471     arg = argv[argn];
 472     if (arg[0] != '-')
 473       break;                    /* not switch, must be file name */
 474     arg++;                      /* advance over '-' */
 475     if (keymatch(arg, "verbose", 1)) {
 476       verbose++;
 477     } else if (keymatch(arg, "raw", 1)) {
 478       raw = 1;
 479     } else
 480       usage();
 481   }
 482
 483   /* Open the input file. */
 484   /* Unix style: expect zero or one file name */
 485   if (argn < argc-1) {
 486     fprintf(stderr, "%s: only one input file\n", progname);
 487     usage();
 488   }
 489   if (argn < argc) {
 490     if ((infile = fopen(argv[argn], READ_BINARY)) == NULL) {
 491       fprintf(stderr, "%s: can't open %s\n", progname, argv[argn]);
 492       exit(EXIT_FAILURE);
 493     }
 494   } else {
 495     /* default input file is stdin */
 496 #ifdef USE_SETMODE              /* need to hack file mode? */
 497     setmode(fileno(stdin), O_BINARY);
 498 #endif
 499 #ifdef USE_FDOPEN               /* need to re-open in binary mode? */
 500     if ((infile = fdopen(fileno(stdin), READ_BINARY)) == NULL) {
 501       fprintf(stderr, "%s: can't open stdin\n", progname);
 502       exit(EXIT_FAILURE);
 503     }
 504 #else
 505     infile = stdin;
 506 #endif
 507   }
 508
 509   /* Scan the JPEG headers. */
 510   (void) scan_JPEG_header(verbose, raw);
 511
 512   /* All done. */
 513   exit(EXIT_SUCCESS);
 514   return 0;                     /* suppress no-return-value warnings */
 515 }