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src/Source/LibJPEG/cjpeg.c  view on Meta::CPAN

#endif
#ifdef THINK_C
#include <console.h>		/* Think declares it here */
#endif
#endif


/* Create the add-on message string table. */

#define JMESSAGE(code,string)	string ,

static const char * const cdjpeg_message_table[] = {
#include "cderror.h"
  NULL
};


/*
 * This routine determines what format the input file is,
 * and selects the appropriate input-reading module.
 *
 * To determine which family of input formats the file belongs to,
 * we may look only at the first byte of the file, since C does not
 * guarantee that more than one character can be pushed back with ungetc.
 * Looking at additional bytes would require one of these approaches:
 *     1) assume we can fseek() the input file (fails for piped input);
 *     2) assume we can push back more than one character (works in
 *        some C implementations, but unportable);
 *     3) provide our own buffering (breaks input readers that want to use
 *        stdio directly, such as the RLE library);
 * or  4) don't put back the data, and modify the input_init methods to assume
 *        they start reading after the start of file (also breaks RLE library).
 * #1 is attractive for MS-DOS but is untenable on Unix.
 *
 * The most portable solution for file types that can't be identified by their
 * first byte is to make the user tell us what they are.  This is also the
 * only approach for "raw" file types that contain only arbitrary values.
 * We presently apply this method for Targa files.  Most of the time Targa
 * files start with 0x00, so we recognize that case.  Potentially, however,
 * a Targa file could start with any byte value (byte 0 is the length of the
 * seldom-used ID field), so we provide a switch to force Targa input mode.
 */

static boolean is_targa;	/* records user -targa switch */


LOCAL(cjpeg_source_ptr)
select_file_type (j_compress_ptr cinfo, FILE * infile)
{
  int c;

  if (is_targa) {
#ifdef TARGA_SUPPORTED
    return jinit_read_targa(cinfo);
#else
    ERREXIT(cinfo, JERR_TGA_NOTCOMP);
#endif
  }

  if ((c = getc(infile)) == EOF)
    ERREXIT(cinfo, JERR_INPUT_EMPTY);
  if (ungetc(c, infile) == EOF)
    ERREXIT(cinfo, JERR_UNGETC_FAILED);

  switch (c) {
#ifdef BMP_SUPPORTED
  case 'B':
    return jinit_read_bmp(cinfo);
#endif
#ifdef GIF_SUPPORTED
  case 'G':
    return jinit_read_gif(cinfo);
#endif
#ifdef PPM_SUPPORTED
  case 'P':
    return jinit_read_ppm(cinfo);
#endif
#ifdef RLE_SUPPORTED
  case 'R':
    return jinit_read_rle(cinfo);
#endif
#ifdef TARGA_SUPPORTED
  case 0x00:
    return jinit_read_targa(cinfo);
#endif
  default:
    ERREXIT(cinfo, JERR_UNKNOWN_FORMAT);
    break;
  }

  return NULL;			/* suppress compiler warnings */
}


/*
 * Argument-parsing code.
 * The switch parser is designed to be useful with DOS-style command line
 * syntax, ie, intermixed switches and file names, where only the switches
 * to the left of a given file name affect processing of that file.
 * The main program in this file doesn't actually use this capability...
 */


static const char * progname;	/* program name for error messages */
static char * outfilename;	/* for -outfile switch */


LOCAL(void)
usage (void)
/* complain about bad command line */
{
  fprintf(stderr, "usage: %s [switches] ", progname);
#ifdef TWO_FILE_COMMANDLINE
  fprintf(stderr, "inputfile outputfile\n");
#else
  fprintf(stderr, "[inputfile]\n");
#endif

  fprintf(stderr, "Switches (names may be abbreviated):\n");
  fprintf(stderr, "  -quality N[,...]   Compression quality (0..100; 5-95 is useful range)\n");
  fprintf(stderr, "  -grayscale     Create monochrome JPEG file\n");
  fprintf(stderr, "  -rgb           Create RGB JPEG file\n");
#ifdef ENTROPY_OPT_SUPPORTED
  fprintf(stderr, "  -optimize      Optimize Huffman table (smaller file, but slow compression)\n");
#endif
#ifdef C_PROGRESSIVE_SUPPORTED
  fprintf(stderr, "  -progressive   Create progressive JPEG file\n");
#endif
#ifdef DCT_SCALING_SUPPORTED
  fprintf(stderr, "  -scale M/N     Scale image by fraction M/N, eg, 1/2\n");
#endif
#ifdef TARGA_SUPPORTED
  fprintf(stderr, "  -targa         Input file is Targa format (usually not needed)\n");
#endif
  fprintf(stderr, "Switches for advanced users:\n");
#ifdef C_ARITH_CODING_SUPPORTED
  fprintf(stderr, "  -arithmetic    Use arithmetic coding\n");
#endif
#ifdef DCT_SCALING_SUPPORTED
  fprintf(stderr, "  -block N       DCT block size (1..16; default is 8)\n");
#endif
#if JPEG_LIB_VERSION_MAJOR >= 9
  fprintf(stderr, "  -rgb1          Create RGB JPEG file with reversible color transform\n");
  fprintf(stderr, "  -bgycc         Create big gamut YCC JPEG file\n");
#endif
#ifdef DCT_ISLOW_SUPPORTED
  fprintf(stderr, "  -dct int       Use integer DCT method%s\n",
	  (JDCT_DEFAULT == JDCT_ISLOW ? " (default)" : ""));
#endif
#ifdef DCT_IFAST_SUPPORTED
  fprintf(stderr, "  -dct fast      Use fast integer DCT (less accurate)%s\n",
	  (JDCT_DEFAULT == JDCT_IFAST ? " (default)" : ""));
#endif
#ifdef DCT_FLOAT_SUPPORTED
  fprintf(stderr, "  -dct float     Use floating-point DCT method%s\n",
	  (JDCT_DEFAULT == JDCT_FLOAT ? " (default)" : ""));
#endif
  fprintf(stderr, "  -nosmooth      Don't use high-quality downsampling\n");
  fprintf(stderr, "  -restart N     Set restart interval in rows, or in blocks with B\n");
#ifdef INPUT_SMOOTHING_SUPPORTED
  fprintf(stderr, "  -smooth N      Smooth dithered input (N=1..100 is strength)\n");
#endif
  fprintf(stderr, "  -maxmemory N   Maximum memory to use (in kbytes)\n");
  fprintf(stderr, "  -outfile name  Specify name for output file\n");
  fprintf(stderr, "  -verbose  or  -debug   Emit debug output\n");
  fprintf(stderr, "Switches for wizards:\n");
  fprintf(stderr, "  -baseline      Force baseline quantization tables\n");
  fprintf(stderr, "  -qtables file  Use quantization tables given in file\n");
  fprintf(stderr, "  -qslots N[,...]    Set component quantization tables\n");
  fprintf(stderr, "  -sample HxV[,...]  Set component sampling factors\n");
#ifdef C_MULTISCAN_FILES_SUPPORTED
  fprintf(stderr, "  -scans file    Create multi-scan JPEG per script file\n");
#endif
  exit(EXIT_FAILURE);
}


LOCAL(int)
parse_switches (j_compress_ptr cinfo, int argc, char **argv,
		int last_file_arg_seen, boolean for_real)
/* Parse optional switches.
 * Returns argv[] index of first file-name argument (== argc if none).
 * Any file names with indexes <= last_file_arg_seen are ignored;
 * they have presumably been processed in a previous iteration.
 * (Pass 0 for last_file_arg_seen on the first or only iteration.)
 * for_real is FALSE on the first (dummy) pass; we may skip any expensive
 * processing.
 */
{
  int argn;
  char * arg;
  boolean force_baseline;
  boolean simple_progressive;
  char * qualityarg = NULL;	/* saves -quality parm if any */
  char * qtablefile = NULL;	/* saves -qtables filename if any */
  char * qslotsarg = NULL;	/* saves -qslots parm if any */
  char * samplearg = NULL;	/* saves -sample parm if any */
  char * scansarg = NULL;	/* saves -scans parm if any */

  /* Set up default JPEG parameters. */

  force_baseline = FALSE;	/* by default, allow 16-bit quantizers */
  simple_progressive = FALSE;
  is_targa = FALSE;
  outfilename = NULL;
  cinfo->err->trace_level = 0;

  /* Scan command line options, adjust parameters */

  for (argn = 1; argn < argc; argn++) {
    arg = argv[argn];
    if (*arg != '-') {
      /* Not a switch, must be a file name argument */
      if (argn <= last_file_arg_seen) {
	outfilename = NULL;	/* -outfile applies to just one input file */
	continue;		/* ignore this name if previously processed */
      }
      break;			/* else done parsing switches */
    }
    arg++;			/* advance past switch marker character */