workbench/libs/jpeg/cjpeg.c

   1 /*
   2  * cjpeg.c
   3  *
   4  * Copyright (C) 1991-1998, Thomas G. Lane.
   5  * Modified 2003-2013 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 command-line user interface for the JPEG compressor.
  10  * It should work on any system with Unix- or MS-DOS-style command lines.
  11  *
  12  * Two different command line styles are permitted, depending on the
  13  * compile-time switch TWO_FILE_COMMANDLINE:
  14  *      cjpeg [options]  inputfile outputfile
  15  *      cjpeg [options]  [inputfile]
  16  * In the second style, output is always to standard output, which you'd
  17  * normally redirect to a file or pipe to some other program.  Input is
  18  * either from a named file or from standard input (typically redirected).
  19  * The second style is convenient on Unix but is unhelpful on systems that
  20  * don't support pipes.  Also, you MUST use the first style if your system
  21  * doesn't do binary I/O to stdin/stdout.
  22  * To simplify script writing, the "-outfile" switch is provided.  The syntax
  23  *      cjpeg [options]  -outfile outputfile  inputfile
  24  * works regardless of which command line style is used.
  25  */
  26
  27 #include "cdjpeg.h"             /* Common decls for cjpeg/djpeg applications */
  28 #include "jversion.h"           /* for version message */
  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
  41 /* Create the add-on message string table. */
  42
  43 #define JMESSAGE(code,string)   string ,
  44
  45 static const char * const cdjpeg_message_table[] = {
  46 #include "cderror.h"
  47   NULL
  48 };
  49
  50
  51 /*
  52  * This routine determines what format the input file is,
  53  * and selects the appropriate input-reading module.
  54  *
  55  * To determine which family of input formats the file belongs to,
  56  * we may look only at the first byte of the file, since C does not
  57  * guarantee that more than one character can be pushed back with ungetc.
  58  * Looking at additional bytes would require one of these approaches:
  59  *     1) assume we can fseek() the input file (fails for piped input);
  60  *     2) assume we can push back more than one character (works in
  61  *        some C implementations, but unportable);
  62  *     3) provide our own buffering (breaks input readers that want to use
  63  *        stdio directly, such as the RLE library);
  64  * or  4) don't put back the data, and modify the input_init methods to assume
  65  *        they start reading after the start of file (also breaks RLE library).
  66  * #1 is attractive for MS-DOS but is untenable on Unix.
  67  *
  68  * The most portable solution for file types that can't be identified by their
  69  * first byte is to make the user tell us what they are.  This is also the
  70  * only approach for "raw" file types that contain only arbitrary values.
  71  * We presently apply this method for Targa files.  Most of the time Targa
  72  * files start with 0x00, so we recognize that case.  Potentially, however,
  73  * a Targa file could start with any byte value (byte 0 is the length of the
  74  * seldom-used ID field), so we provide a switch to force Targa input mode.
  75  */
  76
  77 static boolean is_targa;        /* records user -targa switch */
  78
  79
  80 LOCAL(cjpeg_source_ptr)
  81 select_file_type (j_compress_ptr cinfo, FILE * infile)
  82 {
  83   int c;
  84
  85   if (is_targa) {
  86 #ifdef TARGA_SUPPORTED
  87     return jinit_read_targa(cinfo);
  88 #else
  89     ERREXIT(cinfo, JERR_TGA_NOTCOMP);
  90 #endif
  91   }
  92
  93   if ((c = getc(infile)) == EOF)
  94     ERREXIT(cinfo, JERR_INPUT_EMPTY);
  95   if (ungetc(c, infile) == EOF)
  96     ERREXIT(cinfo, JERR_UNGETC_FAILED);
  97
  98   switch (c) {
  99 #ifdef BMP_SUPPORTED
 100   case 'B':
 101     return jinit_read_bmp(cinfo);
 102 #endif
 103 #ifdef GIF_SUPPORTED
 104   case 'G':
 105     return jinit_read_gif(cinfo);
 106 #endif
 107 #ifdef PPM_SUPPORTED
 108   case 'P':
 109     return jinit_read_ppm(cinfo);
 110 #endif
 111 #ifdef RLE_SUPPORTED
 112   case 'R':
 113     return jinit_read_rle(cinfo);
 114 #endif
 115 #ifdef TARGA_SUPPORTED
 116   case 0x00:
 117     return jinit_read_targa(cinfo);
 118 #endif
 119   default:
 120     ERREXIT(cinfo, JERR_UNKNOWN_FORMAT);
 121     break;
 122   }
 123
 124   return NULL;                  /* suppress compiler warnings */
 125 }
 126
 127
 128 /*
 129  * Argument-parsing code.
 130  * The switch parser is designed to be useful with DOS-style command line
 131  * syntax, ie, intermixed switches and file names, where only the switches
 132  * to the left of a given file name affect processing of that file.
 133  * The main program in this file doesn't actually use this capability...
 134  */
 135
 136
 137 static const char * progname;   /* program name for error messages */
 138 static char * outfilename;      /* for -outfile switch */
 139
 140
 141 LOCAL(void)
 142 usage (void)
 143 /* complain about bad command line */
 144 {
 145   fprintf(stderr, "usage: %s [switches] ", progname);
 146 #ifdef TWO_FILE_COMMANDLINE
 147   fprintf(stderr, "inputfile outputfile\n");
 148 #else
 149   fprintf(stderr, "[inputfile]\n");
 150 #endif
 151
 152   fprintf(stderr, "Switches (names may be abbreviated):\n");
 153   fprintf(stderr, "  -quality N[,...]   Compression quality (0..100; 5-95 is useful range)\n");
 154   fprintf(stderr, "  -grayscale     Create monochrome JPEG file\n");
 155   fprintf(stderr, "  -rgb           Create RGB JPEG file\n");
 156 #ifdef ENTROPY_OPT_SUPPORTED
 157   fprintf(stderr, "  -optimize      Optimize Huffman table (smaller file, but slow compression)\n");
 158 #endif
 159 #ifdef C_PROGRESSIVE_SUPPORTED
 160   fprintf(stderr, "  -progressive   Create progressive JPEG file\n");
 161 #endif
 162 #ifdef DCT_SCALING_SUPPORTED
 163   fprintf(stderr, "  -scale M/N     Scale image by fraction M/N, eg, 1/2\n");
 164 #endif
 165 #ifdef TARGA_SUPPORTED
 166   fprintf(stderr, "  -targa         Input file is Targa format (usually not needed)\n");
 167 #endif
 168   fprintf(stderr, "Switches for advanced users:\n");
 169 #ifdef C_ARITH_CODING_SUPPORTED
 170   fprintf(stderr, "  -arithmetic    Use arithmetic coding\n");
 171 #endif
 172 #ifdef DCT_SCALING_SUPPORTED
 173   fprintf(stderr, "  -block N       DCT block size (1..16; default is 8)\n");
 174 #endif
 175 #if JPEG_LIB_VERSION_MAJOR >= 9
 176   fprintf(stderr, "  -rgb1          Create RGB JPEG file with reversible color transform\n");
 177 #endif
 178 #ifdef DCT_ISLOW_SUPPORTED
 179   fprintf(stderr, "  -dct int       Use integer DCT method%s\n",
 180           (JDCT_DEFAULT == JDCT_ISLOW ? " (default)" : ""));
 181 #endif
 182 #ifdef DCT_IFAST_SUPPORTED
 183   fprintf(stderr, "  -dct fast      Use fast integer DCT (less accurate)%s\n",
 184           (JDCT_DEFAULT == JDCT_IFAST ? " (default)" : ""));
 185 #endif
 186 #ifdef DCT_FLOAT_SUPPORTED
 187   fprintf(stderr, "  -dct float     Use floating-point DCT method%s\n",
 188           (JDCT_DEFAULT == JDCT_FLOAT ? " (default)" : ""));
 189 #endif
 190   fprintf(stderr, "  -nosmooth      Don't use high-quality downsampling\n");
 191   fprintf(stderr, "  -restart N     Set restart interval in rows, or in blocks with B\n");
 192 #ifdef INPUT_SMOOTHING_SUPPORTED
 193   fprintf(stderr, "  -smooth N      Smooth dithered input (N=1..100 is strength)\n");
 194 #endif
 195   fprintf(stderr, "  -maxmemory N   Maximum memory to use (in kbytes)\n");
 196   fprintf(stderr, "  -outfile name  Specify name for output file\n");
 197   fprintf(stderr, "  -verbose  or  -debug   Emit debug output\n");
 198   fprintf(stderr, "Switches for wizards:\n");
 199   fprintf(stderr, "  -baseline      Force baseline quantization tables\n");
 200   fprintf(stderr, "  -qtables file  Use quantization tables given in file\n");
 201   fprintf(stderr, "  -qslots N[,...]    Set component quantization tables\n");
 202   fprintf(stderr, "  -sample HxV[,...]  Set component sampling factors\n");
 203 #ifdef C_MULTISCAN_FILES_SUPPORTED
 204   fprintf(stderr, "  -scans file    Create multi-scan JPEG per script file\n");
 205 #endif
 206   exit(EXIT_FAILURE);
 207 }
 208
 209
 210 LOCAL(int)
 211 parse_switches (j_compress_ptr cinfo, int argc, char **argv,
 212                 int last_file_arg_seen, boolean for_real)
 213 /* Parse optional switches.
 214  * Returns argv[] index of first file-name argument (== argc if none).
 215  * Any file names with indexes <= last_file_arg_seen are ignored;
 216  * they have presumably been processed in a previous iteration.
 217  * (Pass 0 for last_file_arg_seen on the first or only iteration.)
 218  * for_real is FALSE on the first (dummy) pass; we may skip any expensive
 219  * processing.
 220  */
 221 {
 222   int argn;
 223   char * arg;
 224   boolean force_baseline;
 225   boolean simple_progressive;
 226   char * qualityarg = NULL;     /* saves -quality parm if any */
 227   char * qtablefile = NULL;     /* saves -qtables filename if any */
 228   char * qslotsarg = NULL;      /* saves -qslots parm if any */
 229   char * samplearg = NULL;      /* saves -sample parm if any */
 230   char * scansarg = NULL;       /* saves -scans parm if any */
 231
 232   /* Set up default JPEG parameters. */
 233
 234   force_baseline = FALSE;       /* by default, allow 16-bit quantizers */
 235   simple_progressive = FALSE;
 236   is_targa = FALSE;
 237   outfilename = NULL;
 238   cinfo->err->trace_level = 0;
 239
 240   /* Scan command line options, adjust parameters */
 241
 242   for (argn = 1; argn < argc; argn++) {
 243     arg = argv[argn];
 244     if (*arg != '-') {
 245       /* Not a switch, must be a file name argument */
 246       if (argn <= last_file_arg_seen) {
 247         outfilename = NULL;     /* -outfile applies to just one input file */
 248         continue;               /* ignore this name if previously processed */
 249       }
 250       break;                    /* else done parsing switches */
 251     }
 252     arg++;                      /* advance past switch marker character */
 253
 254     if (keymatch(arg, "arithmetic", 1)) {
 255       /* Use arithmetic coding. */
 256 #ifdef C_ARITH_CODING_SUPPORTED
 257       cinfo->arith_code = TRUE;
 258 #else
 259       fprintf(stderr, "%s: sorry, arithmetic coding not supported\n",
 260               progname);
 261       exit(EXIT_FAILURE);
 262 #endif
 263
 264     } else if (keymatch(arg, "baseline", 2)) {
 265       /* Force baseline-compatible output (8-bit quantizer values). */
 266       force_baseline = TRUE;
 267
 268     } else if (keymatch(arg, "block", 2)) {
 269       /* Set DCT block size. */
 270 #if defined DCT_SCALING_SUPPORTED && JPEG_LIB_VERSION_MAJOR >= 8 && \
 271       (JPEG_LIB_VERSION_MAJOR > 8 || JPEG_LIB_VERSION_MINOR >= 3)
 272       int val;
 273
 274       if (++argn >= argc)       /* advance to next argument */
 275         usage();
 276       if (sscanf(argv[argn], "%d", &val) != 1)
 277         usage();
 278       if (val < 1 || val > 16)
 279         usage();
 280       cinfo->block_size = val;
 281 #else
 282       fprintf(stderr, "%s: sorry, block size setting not supported\n",
 283               progname);
 284       exit(EXIT_FAILURE);
 285 #endif
 286
 287     } else if (keymatch(arg, "dct", 2)) {
 288       /* Select DCT algorithm. */
 289       if (++argn >= argc)       /* advance to next argument */
 290         usage();
 291       if (keymatch(argv[argn], "int", 1)) {
 292         cinfo->dct_method = JDCT_ISLOW;
 293       } else if (keymatch(argv[argn], "fast", 2)) {
 294         cinfo->dct_method = JDCT_IFAST;
 295       } else if (keymatch(argv[argn], "float", 2)) {
 296         cinfo->dct_method = JDCT_FLOAT;
 297       } else
 298         usage();
 299
 300     } else if (keymatch(arg, "debug", 1) || keymatch(arg, "verbose", 1)) {
 301       /* Enable debug printouts. */
 302       /* On first -d, print version identification */
 303       static boolean printed_version = FALSE;
 304
 305       if (! printed_version) {
 306         fprintf(stderr, "Independent JPEG Group's CJPEG, version %s\n%s\n",
 307                 JVERSION, JCOPYRIGHT);
 308         printed_version = TRUE;
 309       }
 310       cinfo->err->trace_level++;
 311
 312     } else if (keymatch(arg, "grayscale", 2) || keymatch(arg, "greyscale",2)) {
 313       /* Force a monochrome JPEG file to be generated. */
 314       jpeg_set_colorspace(cinfo, JCS_GRAYSCALE);
 315
 316     } else if (keymatch(arg, "rgb", 3) || keymatch(arg, "rgb1", 4)) {
 317       /* Force an RGB JPEG file to be generated. */
 318 #if JPEG_LIB_VERSION_MAJOR >= 9
 319       /* Note: Entropy table assignment in jpeg_set_colorspace depends
 320        * on color_transform.
 321        */
 322       cinfo->color_transform = arg[3] ? JCT_SUBTRACT_GREEN : JCT_NONE;
 323 #endif
 324       jpeg_set_colorspace(cinfo, JCS_RGB);
 325
 326     } else if (keymatch(arg, "maxmemory", 3)) {
 327       /* Maximum memory in Kb (or Mb with 'm'). */
 328       long lval;
 329       char ch = 'x';
 330
 331       if (++argn >= argc)       /* advance to next argument */
 332         usage();
 333       if (sscanf(argv[argn], "%ld%c", &lval, &ch) < 1)
 334         usage();
 335       if (ch == 'm' || ch == 'M')
 336         lval *= 1000L;
 337       cinfo->mem->max_memory_to_use = lval * 1000L;
 338
 339     } else if (keymatch(arg, "nosmooth", 3)) {
 340       /* Suppress fancy downsampling. */
 341       cinfo->do_fancy_downsampling = FALSE;
 342
 343     } else if (keymatch(arg, "optimize", 1) || keymatch(arg, "optimise", 1)) {
 344       /* Enable entropy parm optimization. */
 345 #ifdef ENTROPY_OPT_SUPPORTED
 346       cinfo->optimize_coding = TRUE;
 347 #else
 348       fprintf(stderr, "%s: sorry, entropy optimization was not compiled\n",
 349               progname);
 350       exit(EXIT_FAILURE);
 351 #endif
 352
 353     } else if (keymatch(arg, "outfile", 4)) {
 354       /* Set output file name. */
 355       if (++argn >= argc)       /* advance to next argument */
 356         usage();
 357       outfilename = argv[argn]; /* save it away for later use */
 358
 359     } else if (keymatch(arg, "progressive", 1)) {
 360       /* Select simple progressive mode. */
 361 #ifdef C_PROGRESSIVE_SUPPORTED
 362       simple_progressive = TRUE;
 363       /* We must postpone execution until num_components is known. */
 364 #else
 365       fprintf(stderr, "%s: sorry, progressive output was not compiled\n",
 366               progname);
 367       exit(EXIT_FAILURE);
 368 #endif
 369
 370     } else if (keymatch(arg, "quality", 1)) {
 371       /* Quality ratings (quantization table scaling factors). */
 372       if (++argn >= argc)       /* advance to next argument */
 373         usage();
 374       qualityarg = argv[argn];
 375
 376     } else if (keymatch(arg, "qslots", 2)) {
 377       /* Quantization table slot numbers. */
 378       if (++argn >= argc)       /* advance to next argument */
 379         usage();
 380       qslotsarg = argv[argn];
 381       /* Must delay setting qslots until after we have processed any
 382        * colorspace-determining switches, since jpeg_set_colorspace sets
 383        * default quant table numbers.
 384        */
 385
 386     } else if (keymatch(arg, "qtables", 2)) {
 387       /* Quantization tables fetched from file. */
 388       if (++argn >= argc)       /* advance to next argument */
 389         usage();
 390       qtablefile = argv[argn];
 391       /* We postpone actually reading the file in case -quality comes later. */
 392
 393     } else if (keymatch(arg, "restart", 1)) {
 394       /* Restart interval in MCU rows (or in MCUs with 'b'). */
 395       long lval;
 396       char ch = 'x';
 397
 398       if (++argn >= argc)       /* advance to next argument */
 399         usage();
 400       if (sscanf(argv[argn], "%ld%c", &lval, &ch) < 1)
 401         usage();
 402       if (lval < 0 || lval > 65535L)
 403         usage();
 404       if (ch == 'b' || ch == 'B') {
 405         cinfo->restart_interval = (unsigned int) lval;
 406         cinfo->restart_in_rows = 0; /* else prior '-restart n' overrides me */
 407       } else {
 408         cinfo->restart_in_rows = (int) lval;
 409         /* restart_interval will be computed during startup */
 410       }
 411
 412     } else if (keymatch(arg, "sample", 2)) {
 413       /* Set sampling factors. */
 414       if (++argn >= argc)       /* advance to next argument */
 415         usage();
 416       samplearg = argv[argn];
 417       /* Must delay setting sample factors until after we have processed any
 418        * colorspace-determining switches, since jpeg_set_colorspace sets
 419        * default sampling factors.
 420        */
 421
 422     } else if (keymatch(arg, "scale", 4)) {
 423       /* Scale the image by a fraction M/N. */
 424       if (++argn >= argc)       /* advance to next argument */
 425         usage();
 426       if (sscanf(argv[argn], "%u/%u",
 427                  &cinfo->scale_num, &cinfo->scale_denom) != 2)
 428         usage();
 429
 430     } else if (keymatch(arg, "scans", 4)) {
 431       /* Set scan script. */
 432 #ifdef C_MULTISCAN_FILES_SUPPORTED
 433       if (++argn >= argc)       /* advance to next argument */
 434         usage();
 435       scansarg = argv[argn];
 436       /* We must postpone reading the file in case -progressive appears. */
 437 #else
 438       fprintf(stderr, "%s: sorry, multi-scan output was not compiled\n",
 439               progname);
 440       exit(EXIT_FAILURE);
 441 #endif
 442
 443     } else if (keymatch(arg, "smooth", 2)) {
 444       /* Set input smoothing factor. */
 445       int val;
 446
 447       if (++argn >= argc)       /* advance to next argument */
 448         usage();
 449       if (sscanf(argv[argn], "%d", &val) != 1)
 450         usage();
 451       if (val < 0 || val > 100)
 452         usage();
 453       cinfo->smoothing_factor = val;
 454
 455     } else if (keymatch(arg, "targa", 1)) {
 456       /* Input file is Targa format. */
 457       is_targa = TRUE;
 458
 459     } else {
 460       usage();                  /* bogus switch */
 461     }
 462   }
 463
 464   /* Post-switch-scanning cleanup */
 465
 466   if (for_real) {
 467
 468     /* Set quantization tables for selected quality. */
 469     /* Some or all may be overridden if -qtables is present. */
 470     if (qualityarg != NULL)     /* process -quality if it was present */
 471       if (! set_quality_ratings(cinfo, qualityarg, force_baseline))
 472         usage();
 473
 474     if (qtablefile != NULL)     /* process -qtables if it was present */
 475       if (! read_quant_tables(cinfo, qtablefile, force_baseline))
 476         usage();
 477
 478     if (qslotsarg != NULL)      /* process -qslots if it was present */
 479       if (! set_quant_slots(cinfo, qslotsarg))
 480         usage();
 481
 482     if (samplearg != NULL)      /* process -sample if it was present */
 483       if (! set_sample_factors(cinfo, samplearg))
 484         usage();
 485
 486 #ifdef C_PROGRESSIVE_SUPPORTED
 487     if (simple_progressive)     /* process -progressive; -scans can override */
 488       jpeg_simple_progression(cinfo);
 489 #endif
 490
 491 #ifdef C_MULTISCAN_FILES_SUPPORTED
 492     if (scansarg != NULL)       /* process -scans if it was present */
 493       if (! read_scan_script(cinfo, scansarg))
 494         usage();
 495 #endif
 496   }
 497
 498   return argn;                  /* return index of next arg (file name) */
 499 }
 500
 501
 502 /*
 503  * The main program.
 504  */
 505
 506 int
 507 main (int argc, char **argv)
 508 {
 509   struct jpeg_compress_struct cinfo;
 510   struct jpeg_error_mgr jerr;
 511 #ifdef PROGRESS_REPORT
 512   struct cdjpeg_progress_mgr progress;
 513 #endif
 514   int file_index;
 515   cjpeg_source_ptr src_mgr;
 516   FILE * input_file;
 517   FILE * output_file;
 518   JDIMENSION num_scanlines;
 519
 520   /* On Mac, fetch a command line. */
 521 #ifdef USE_CCOMMAND
 522   argc = ccommand(&argv);
 523 #endif
 524
 525   progname = argv[0];
 526   if (progname == NULL || progname[0] == 0)
 527     progname = "cjpeg";         /* in case C library doesn't provide it */
 528
 529   /* Initialize the JPEG compression object with default error handling. */
 530   cinfo.err = jpeg_std_error(&jerr);
 531   jpeg_create_compress(&cinfo);
 532   /* Add some application-specific error messages (from cderror.h) */
 533   jerr.addon_message_table = cdjpeg_message_table;
 534   jerr.first_addon_message = JMSG_FIRSTADDONCODE;
 535   jerr.last_addon_message = JMSG_LASTADDONCODE;
 536
 537   /* Now safe to enable signal catcher. */
 538 #ifdef NEED_SIGNAL_CATCHER
 539   enable_signal_catcher((j_common_ptr) &cinfo);
 540 #endif
 541
 542   /* Initialize JPEG parameters.
 543    * Much of this may be overridden later.
 544    * In particular, we don't yet know the input file's color space,
 545    * but we need to provide some value for jpeg_set_defaults() to work.
 546    */
 547
 548   cinfo.in_color_space = JCS_RGB; /* arbitrary guess */
 549   jpeg_set_defaults(&cinfo);
 550
 551   /* Scan command line to find file names.
 552    * It is convenient to use just one switch-parsing routine, but the switch
 553    * values read here are ignored; we will rescan the switches after opening
 554    * the input file.
 555    */
 556
 557   file_index = parse_switches(&cinfo, argc, argv, 0, FALSE);
 558
 559 #ifdef TWO_FILE_COMMANDLINE
 560   /* Must have either -outfile switch or explicit output file name */
 561   if (outfilename == NULL) {
 562     if (file_index != argc-2) {
 563       fprintf(stderr, "%s: must name one input and one output file\n",
 564               progname);
 565       usage();
 566     }
 567     outfilename = argv[file_index+1];
 568   } else {
 569     if (file_index != argc-1) {
 570       fprintf(stderr, "%s: must name one input and one output file\n",
 571               progname);
 572       usage();
 573     }
 574   }
 575 #else
 576   /* Unix style: expect zero or one file name */
 577   if (file_index < argc-1) {
 578     fprintf(stderr, "%s: only one input file\n", progname);
 579     usage();
 580   }
 581 #endif /* TWO_FILE_COMMANDLINE */
 582
 583   /* Open the input file. */
 584   if (file_index < argc) {
 585     if ((input_file = fopen(argv[file_index], READ_BINARY)) == NULL) {
 586       fprintf(stderr, "%s: can't open %s\n", progname, argv[file_index]);
 587       exit(EXIT_FAILURE);
 588     }
 589   } else {
 590     /* default input file is stdin */
 591     input_file = read_stdin();
 592   }
 593
 594   /* Open the output file. */
 595   if (outfilename != NULL) {
 596     if ((output_file = fopen(outfilename, WRITE_BINARY)) == NULL) {
 597       fprintf(stderr, "%s: can't open %s\n", progname, outfilename);
 598       exit(EXIT_FAILURE);
 599     }
 600   } else {
 601     /* default output file is stdout */
 602     output_file = write_stdout();
 603   }
 604
 605 #ifdef PROGRESS_REPORT
 606   start_progress_monitor((j_common_ptr) &cinfo, &progress);
 607 #endif
 608
 609   /* Figure out the input file format, and set up to read it. */
 610   src_mgr = select_file_type(&cinfo, input_file);
 611   src_mgr->input_file = input_file;
 612
 613   /* Read the input file header to obtain file size & colorspace. */
 614   (*src_mgr->start_input) (&cinfo, src_mgr);
 615
 616   /* Now that we know input colorspace, fix colorspace-dependent defaults */
 617   jpeg_default_colorspace(&cinfo);
 618
 619   /* Adjust default compression parameters by re-parsing the options */
 620   file_index = parse_switches(&cinfo, argc, argv, 0, TRUE);
 621
 622   /* Specify data destination for compression */
 623   jpeg_stdio_dest(&cinfo, output_file);
 624
 625   /* Start compressor */
 626   jpeg_start_compress(&cinfo, TRUE);
 627
 628   /* Process data */
 629   while (cinfo.next_scanline < cinfo.image_height) {
 630     num_scanlines = (*src_mgr->get_pixel_rows) (&cinfo, src_mgr);
 631     (void) jpeg_write_scanlines(&cinfo, src_mgr->buffer, num_scanlines);
 632   }
 633
 634   /* Finish compression and release memory */
 635   (*src_mgr->finish_input) (&cinfo, src_mgr);
 636   jpeg_finish_compress(&cinfo);
 637   jpeg_destroy_compress(&cinfo);
 638
 639   /* Close files, if we opened them */
 640   if (input_file != stdin)
 641     fclose(input_file);
 642   if (output_file != stdout)
 643     fclose(output_file);
 644
 645 #ifdef PROGRESS_REPORT
 646   end_progress_monitor((j_common_ptr) &cinfo);
 647 #endif
 648
 649   /* All done. */
 650   exit(jerr.num_warnings ? EXIT_WARNING : EXIT_SUCCESS);
 651   return 0;                     /* suppress no-return-value warnings */
 652 }