jpegtran.c

linux下的jpeg解码库

/*
 * jpegtran.c
 *
 * Copyright (C) 1995-1997, Thomas G. Lane.
 * This file is part of the Independent JPEG Group's software.
 * For conditions of distribution and use, see the accompanying README file.
 *
 * This file contains a command-line user interface for JPEG transcoding.
 * It is very similar to cjpeg.c, but provides lossless transcoding between
 * different JPEG file formats.  It also provides some lossless and sort-of-
 * lossless transformations of JPEG data.
 */

#include "cdjpeg.h"		/* Common decls for cjpeg/djpeg applications */
#include "transupp.h"		/* Support routines for jpegtran */
#include "jversion.h"		/* for version message */

#ifdef USE_CCOMMAND		/* command-line reader for Macintosh */
#ifdef __MWERKS__
#include <SIOUX.h>              /* Metrowerks needs this */
#include <console.h>		/* ... and this */
#endif
#ifdef THINK_C
#include <console.h>		/* Think declares it here */
#endif
#endif


/*
 * 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 */
static JCOPY_OPTION copyoption;	/* -copy switch */
static jpeg_transform_info transformoption; /* image transformation options */


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, "  -copy none     Copy no extra markers from source file\n");
  fprintf(stderr, "  -copy comments Copy only comment markers (default)\n");
  fprintf(stderr, "  -copy all      Copy all extra markers\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
#if TRANSFORMS_SUPPORTED
  fprintf(stderr, "Switches for modifying the image:\n");
  fprintf(stderr, "  -grayscale     Reduce to grayscale (omit color data)\n");
  fprintf(stderr, "  -flip [horizontal|vertical]  Mirror image (left-right or top-bottom)\n");
  fprintf(stderr, "  -rotate [90|180|270]         Rotate image (degrees clockwise)\n");
  fprintf(stderr, "  -transpose     Transpose image\n");
  fprintf(stderr, "  -transverse    Transverse transpose image\n");
  fprintf(stderr, "  -trim          Drop non-transformable edge blocks\n");
#endif /* TRANSFORMS_SUPPORTED */
  fprintf(stderr, "Switches for advanced users:\n");
  fprintf(stderr, "  -restart N     Set restart interval in rows, or in blocks with B\n");
  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");
#ifdef C_ARITH_CODING_SUPPORTED
  fprintf(stderr, "  -arithmetic    Use arithmetic coding\n");
#endif
#ifdef C_MULTISCAN_FILES_SUPPORTED
  fprintf(stderr, "  -scans file    Create multi-scan JPEG per script file\n");
#endif
  exit(EXIT_FAILURE);
}


LOCAL(void)
select_transform (JXFORM_CODE transform)
/* Silly little routine to detect multiple transform options,
 * which we can't handle.
 */
{
#if TRANSFORMS_SUPPORTED
  if (transformoption.transform == JXFORM_NONE ||
      transformoption.transform == transform) {
    transformoption.transform = transform;
  } else {
    fprintf(stderr, "%s: can only do one image transformation at a time\n",
	    progname);
    usage();
  }
#else
  fprintf(stderr, "%s: sorry, image transformation was not compiled\n",
	  progname);
  exit(EXIT_FAILURE);
#endif
}


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 simple_progressive;
  char * scansarg = NULL;	/* saves -scans parm if any */

  /* Set up default JPEG parameters. */
  simple_progressive = FALSE;
  outfilename = NULL;
  copyoption = JCOPYOPT_DEFAULT;
  transformoption.transform = JXFORM_NONE;
  transformoption.trim = FALSE;
  transformoption.force_grayscale = FALSE;
  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 */

    if (keymatch(arg, "arithmetic", 1)) {
      /* Use arithmetic coding. */
#ifdef C_ARITH_CODING_SUPPORTED
      cinfo->arith_code = TRUE;
#else
      fprintf(stderr, "%s: sorry, arithmetic coding not supported\n",
	      progname);
      exit(EXIT_FAILURE);
#endif

    } else if (keymatch(arg, "copy", 1)) {
      /* Select which extra markers to copy. */
      if (++argn >= argc)	/* advance to next argument */
	usage();
      if (keymatch(argv[argn], "none", 1)) {
	copyoption = JCOPYOPT_NONE;
      } else if (keymatch(argv[argn], "comments", 1)) {
	copyoption = JCOPYOPT_COMMENTS;
      } else if (keymatch(argv[argn], "all", 1)) {
	copyoption = JCOPYOPT_ALL;
      } else
	usage();

    } else if (keymatch(arg, "debug", 1) || keymatch(arg, "verbose", 1)) {
      /* Enable debug printouts. */
      /* On first -d, print version identification */
      static boolean printed_version = FALSE;

      if (! printed_version) {
	fprintf(stderr, "Independent JPEG Group's JPEGTRAN, version %s\n%s\n",
		JVERSION, JCOPYRIGHT);
	printed_version = TRUE;
      }
      cinfo->err->trace_level++;

    } else if (keymatch(arg, "flip", 1)) {
      /* Mirror left-right or top-bottom. */
      if (++argn >= argc)	/* advance to next argument */
	usage();
      if (keymatch(argv[argn], "horizontal", 1))
	select_transform(JXFORM_FLIP_H);
      else if (keymatch(argv[argn], "vertical", 1))
	select_transform(JXFORM_FLIP_V);
      else
	usage();

    } else if (keymatch(arg, "grayscale", 1) || keymatch(arg, "greyscale",1)) {
      /* Force to grayscale. */
#if TRANSFORMS_SUPPORTED
      transformoption.force_grayscale = TRUE;
#else
      select_transform(JXFORM_NONE);	/* force an error */
#endif

    } else if (keymatch(arg, "maxmemory", 3)) {
      /* Maximum memory in Kb (or Mb with 'm'). */
      long lval;
      char ch = 'x';

      if (++argn >= argc)	/* advance to next argument */
	usage();
      if (sscanf(argv[argn], "%ld%c", &lval, &ch) < 1)
	usage();
      if (ch == 'm' || ch == 'M')
	lval *= 1000L;
      cinfo->mem->max_memory_to_use = lval * 1000L;

    } else if (keymatch(arg, "optimize", 1) || keymatch(arg, "optimise", 1)) {
      /* Enable entropy parm optimization. */
#ifdef ENTROPY_OPT_SUPPORTED
      cinfo->optimize_coding = TRUE;
#else
      fprintf(stderr, "%s: sorry, entropy optimization was not compiled\n",
	      progname);
      exit(EXIT_FAILURE);
#endif

    } else if (keymatch(arg, "outfile", 4)) {
      /* Set output file name. */
      if (++argn >= argc)	/* advance to next argument */
	usage();
      outfilename = argv[argn];	/* save it away for later use */

    } else if (keymatch(arg, "progressive", 1)) {
      /* Select simple progressive mode. */
#ifdef C_PROGRESSIVE_SUPPORTED
      simple_progressive = TRUE;
      /* We must postpone execution until num_components is known. */
#else
      fprintf(stderr, "%s: sorry, progressive output was not compiled\n",
	      progname);
      exit(EXIT_FAILURE);
#endif

    } else if (keymatch(arg, "restart", 1)) {
      /* Restart interval in MCU rows (or in MCUs with 'b'). */
      long lval;
      char ch = 'x';

      if (++argn >= argc)	/* advance to next argument */
	usage();