djpeg.c

来自「JPEG解压源码」· C语言 代码 · 共 751 行 · 第 1/2 页

/*
 * alternate djpeg.c
 *
 * Copyright (C) 1991-1997, 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 an alternate user interface for the JPEG decompressor.
 * One or more input files are named on the command line, and output file
 * names are created by substituting an appropriate extension.
 */

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

#include <ctype.h>		/* to declare isprint() */

#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

#ifndef PATH_MAX		/* ANSI maximum-pathname-length constant */
#define PATH_MAX 256
#endif


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

#define JMESSAGE(code,string)	string ,

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


/*
 * Automatic determination of available memory.
 */

static long default_maxmem;	/* saves value determined at startup, or 0 */

#ifndef FREE_MEM_ESTIMATE	/* may be defined from command line */

#ifdef MSDOS			/* For MS-DOS (unless flat-memory model) */

#include <dos.h>		/* for access to intdos() call */

LOCAL(long)
unused_dos_memory (void)
/* Obtain total amount of unallocated DOS memory */
{
  union REGS regs;
  long nparas;

  regs.h.ah = 0x48;		/* DOS function Allocate Memory Block */
  regs.x.bx = 0xFFFF;		/* Ask for more memory than DOS can have */
  (void) intdos(&regs, &regs);
  /* DOS will fail and return # of paragraphs actually available in BX. */
  nparas = (unsigned int) regs.x.bx;
  /* Times 16 to convert to bytes. */
  return nparas << 4;
}

/* The default memory setting is 95% of the available space. */
#define FREE_MEM_ESTIMATE  ((unused_dos_memory() * 95L) / 100L)

#endif /* MSDOS */

#ifdef ATARI			/* For Atari ST/STE/TT, Pure C or Turbo C */

#include <ext.h>

/* The default memory setting is 90% of the available space. */
#define FREE_MEM_ESTIMATE  (((long) coreleft() * 90L) / 100L)

#endif /* ATARI */

/* Add memory-estimation procedures for other operating systems here,
 * with appropriate #ifdef's around them.
 */

#endif /* !FREE_MEM_ESTIMATE */


/*
 * This list defines the known output image formats
 * (not all of which need be supported by a given version).
 * You can change the default output format by defining DEFAULT_FMT;
 * indeed, you had better do so if you undefine PPM_SUPPORTED.
 */

typedef enum {
	FMT_BMP,		/* BMP format (Windows flavor) */
	FMT_GIF,		/* GIF format */
	FMT_OS2,		/* BMP format (OS/2 flavor) */
	FMT_PPM,		/* PPM/PGM (PBMPLUS formats) */
	FMT_RLE,		/* RLE format */
	FMT_TARGA,		/* Targa format */
	FMT_TIFF		/* TIFF format */
} IMAGE_FORMATS;

#ifndef DEFAULT_FMT		/* so can override from CFLAGS in Makefile */
#define DEFAULT_FMT	FMT_GIF
#endif

static IMAGE_FORMATS requested_fmt;


/*
 * 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.
 */


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] inputfile(s)\n", progname);
  fprintf(stderr, "List of input files may use wildcards (* and ?)\n");
  fprintf(stderr, "Output filename is same as input filename except for extension\n");

  fprintf(stderr, "Switches (names may be abbreviated):\n");
  fprintf(stderr, "  -colors N      Reduce image to no more than N colors\n");
  fprintf(stderr, "  -fast          Fast, low-quality processing\n");
  fprintf(stderr, "  -grayscale     Force grayscale output\n");
#ifdef IDCT_SCALING_SUPPORTED
  fprintf(stderr, "  -scale M/N     Scale output image by fraction M/N, eg, 1/8\n");
#endif
#ifdef BMP_SUPPORTED
  fprintf(stderr, "  -bmp           Select BMP output format (Windows style)%s\n",
	  (DEFAULT_FMT == FMT_BMP ? " (default)" : ""));
#endif
#ifdef GIF_SUPPORTED
  fprintf(stderr, "  -gif           Select GIF output format%s\n",
	  (DEFAULT_FMT == FMT_GIF ? " (default)" : ""));
#endif
#ifdef BMP_SUPPORTED
  fprintf(stderr, "  -os2           Select BMP output format (OS/2 style)%s\n",
	  (DEFAULT_FMT == FMT_OS2 ? " (default)" : ""));
#endif
#ifdef PPM_SUPPORTED
  fprintf(stderr, "  -pnm           Select PBMPLUS (PPM/PGM) output format%s\n",
	  (DEFAULT_FMT == FMT_PPM ? " (default)" : ""));
#endif
#ifdef RLE_SUPPORTED
  fprintf(stderr, "  -rle           Select Utah RLE output format%s\n",
	  (DEFAULT_FMT == FMT_RLE ? " (default)" : ""));
#endif
#ifdef TARGA_SUPPORTED
  fprintf(stderr, "  -targa         Select Targa output format%s\n",
	  (DEFAULT_FMT == FMT_TARGA ? " (default)" : ""));
#endif
  fprintf(stderr, "Switches for advanced users:\n");
#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, "  -dither fs     Use F-S dithering (default)\n");
  fprintf(stderr, "  -dither none   Don't use dithering in quantization\n");
  fprintf(stderr, "  -dither ordered  Use ordered dither (medium speed, quality)\n");
#ifdef QUANT_2PASS_SUPPORTED
  fprintf(stderr, "  -map FILE      Map to colors used in named image file\n");
#endif
  fprintf(stderr, "  -nosmooth      Don't use high-quality upsampling\n");
#ifdef QUANT_1PASS_SUPPORTED
  fprintf(stderr, "  -onepass       Use 1-pass quantization (fast, low quality)\n");
#endif
#ifndef FREE_MEM_ESTIMATE
  fprintf(stderr, "  -maxmemory N   Maximum memory to use (in kbytes)\n");
#endif
  fprintf(stderr, "  -outfile name  Specify name for output file\n");
  fprintf(stderr, "  -verbose  or  -debug   Emit debug output\n");
  exit(EXIT_FAILURE);
}


LOCAL(int)
parse_switches (j_decompress_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;

  /* Set up default JPEG parameters. */
  requested_fmt = DEFAULT_FMT;	/* set default output file format */
  outfilename = NULL;
  cinfo->err->trace_level = 0;
  if (default_maxmem > 0)	/* override library's default value */
    cinfo->mem->max_memory_to_use = default_maxmem;

  /* 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, "bmp", 1)) {
      /* BMP output format. */
      requested_fmt = FMT_BMP;

    } else if (keymatch(arg, "colors", 1) || keymatch(arg, "colours", 1) ||
	       keymatch(arg, "quantize", 1) || keymatch(arg, "quantise", 1)) {
      /* Do color quantization. */
      int val;

      if (++argn >= argc)	/* advance to next argument */
	usage();
      if (sscanf(argv[argn], "%d", &val) != 1)
	usage();
      cinfo->desired_number_of_colors = val;
      cinfo->quantize_colors = TRUE;

    } else if (keymatch(arg, "dct", 2)) {
      /* Select IDCT algorithm. */
      if (++argn >= argc)	/* advance to next argument */
	usage();
      if (keymatch(argv[argn], "int", 1)) {
	cinfo->dct_method = JDCT_ISLOW;
      } else if (keymatch(argv[argn], "fast", 2)) {
	cinfo->dct_method = JDCT_IFAST;
      } else if (keymatch(argv[argn], "float", 2)) {
	cinfo->dct_method = JDCT_FLOAT;
      } else
	usage();

    } else if (keymatch(arg, "dither", 2)) {
      /* Select dithering algorithm. */
      if (++argn >= argc)	/* advance to next argument */
	usage();
      if (keymatch(argv[argn], "fs", 2)) {
	cinfo->dither_mode = JDITHER_FS;
      } else if (keymatch(argv[argn], "none", 2)) {
	cinfo->dither_mode = JDITHER_NONE;
      } else if (keymatch(argv[argn], "ordered", 2)) {
	cinfo->dither_mode = JDITHER_ORDERED;
      } 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 DJPEG, version %s\n%s\n",
		JVERSION, JCOPYRIGHT);
	printed_version = TRUE;
      }
      cinfo->err->trace_level++;

    } else if (keymatch(arg, "fast", 1)) {
      /* Select recommended processing options for quick-and-dirty output. */
      cinfo->two_pass_quantize = FALSE;
      cinfo->dither_mode = JDITHER_ORDERED;
      if (! cinfo->quantize_colors) /* don't override an earlier -colors */
	cinfo->desired_number_of_colors = 216;
      cinfo->dct_method = JDCT_FASTEST;
      cinfo->do_fancy_upsampling = FALSE;

    } else if (keymatch(arg, "gif", 1)) {
      /* GIF output format. */
      requested_fmt = FMT_GIF;

    } else if (keymatch(arg, "grayscale", 2) || keymatch(arg, "greyscale",2)) {
      /* Force monochrome output. */
      cinfo->out_color_space = JCS_GRAYSCALE;

    } else if (keymatch(arg, "map", 3)) {
      /* Quantize to a color map taken from an input file. */
      if (++argn >= argc)	/* advance to next argument */
	usage();
      if (for_real) {		/* too expensive to do twice! */
#ifdef QUANT_2PASS_SUPPORTED	/* otherwise can't quantize to supplied map */
	FILE * mapfile;

	if ((mapfile = fopen(argv[argn], READ_BINARY)) == NULL) {
	  fprintf(stderr, "%s: can't open %s\n", progname, argv[argn]);
	  exit(EXIT_FAILURE);
	}
	read_color_map(cinfo, mapfile);
	fclose(mapfile);
	cinfo->quantize_colors = TRUE;
#else
	ERREXIT(cinfo, JERR_NOT_COMPILED);
#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, "nosmooth", 3)) {
      /* Suppress fancy upsampling */
      cinfo->do_fancy_upsampling = FALSE;

    } else if (keymatch(arg, "onepass", 3)) {
      /* Use fast one-pass quantization. */
      cinfo->two_pass_quantize = FALSE;

    } else if (keymatch(arg, "os2", 3)) {
      /* BMP output format (OS/2 flavor). */
      requested_fmt = FMT_OS2;

    } 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, "pnm", 1) || keymatch(arg, "ppm", 1)) {
      /* PPM/PGM output format. */
      requested_fmt = FMT_PPM;

    } else if (keymatch(arg, "rle", 1)) {
      /* RLE output format. */
      requested_fmt = FMT_RLE;

    } else if (keymatch(arg, "scale", 1)) {
      /* Scale the output image by a fraction M/N. */
      if (++argn >= argc)	/* advance to next argument */
	usage();
      if (sscanf(argv[argn], "%d/%d",
		 &cinfo->scale_num, &cinfo->scale_denom) != 2)
	usage();

    } else if (keymatch(arg, "targa", 1)) {
      /* Targa output format. */
      requested_fmt = FMT_TARGA;