src/xxd/xxd.c

/* xxd: my hexdump facility. jw
 *
 *  2.10.90 changed to word output
 *  3.03.93 new indent style, dumb bug inserted and fixed.
 *	    -c option, mls
 * 26.04.94 better option parser, -ps, -l, -s added.
 *  1.07.94 -r badly needs - as input file.  Per default autoskip over
 *	       consecutive lines of zeroes, as unix od does.
 *	    -a shows them too.
 *	    -i dump as c-style #include "file.h"
 *  1.11.95 if "xxd -i" knows the filename, an 'unsigned char filename_bits[]'
 *	    array is written in correct c-syntax.
 *	    -s improved, now defaults to absolute seek, relative requires a '+'.
 *	    -r improved, now -r -s -0x... is supported.
 *	       change/suppress leading '\0' bytes.
 *	    -l n improved: stops exactly after n bytes.
 *	    -r improved, better handling of partial lines with trailing garbage.
 *	    -r improved, now -r -p works again!
 *	    -r improved, less flushing, much faster now! (that was silly)
 *  3.04.96 Per repeated request of a single person: autoskip defaults to off.
 * 15.05.96 -v added. They want to know the version.
 *	    -a fixed, to show last line inf file ends in all zeros.
 *	    -u added: Print upper case hex-letters, as preferred by unix bc.
 *	    -h added to usage message. Usage message extended.
 *	    Now using outfile if specified even in normal mode, aehem.
 *	    No longer mixing of ints and longs. May help doze people.
 *	    Added binify ioctl for same reason. (Enough Doze stress for 1996!)
 * 16.05.96 -p improved, removed occasional superfluous linefeed.
 * 20.05.96 -l 0 fixed. tried to read anyway.
 * 21.05.96 -i fixed. now honours -u, and prepends __ to numeric filenames.
 *	    compile -DWIN32 for NT or W95. George V. Reilly, * -v improved :-)
 *	    support --gnuish-longhorn-options
 * 25.05.96 MAC support added: CodeWarrior already uses ``outline'' in Types.h
 *	    which is included by MacHeaders (Axel Kielhorn). Renamed to
 *	    xxdline().
 *  7.06.96 -i printed 'int' instead of 'char'. *blush*
 *	    added Bram's OS2 ifdefs...
 * 18.07.96 gcc -Wall @ SunOS4 is now silent.
 *	    Added osver for MSDOS/DJGPP/WIN32.
 * 29.08.96 Added size_t to strncmp() for Amiga.
 * 24.03.97 Windows NT support (Phil Hanna). Clean exit for Amiga WB (Bram)
 * 02.04.97 Added -E option, to have EBCDIC translation instead of ASCII
 *	    (azc10@yahoo.com)
 * 22.05.97 added -g (group octets) option (jcook@namerica.kla.com).
 * 23.09.98 nasty -p -r misfeature fixed: slightly wrong output, when -c was
 *	    missing or wrong.
 * 26.09.98 Fixed: 'xxd -i infile outfile' did not truncate outfile.
 * 27.10.98 Fixed: -g option parser required blank.
 *	    option -b added: 01000101 binary output in normal format.
 * 16.05.00 Added VAXC changes by Stephen P. Wall
 * 16.05.00 Improved MMS file and merge for VMS by Zoltan Arpadffy
 * 2011 March  Better error handling by Florian Zumbiehl.
 * 2011 April  Formatting by Bram Moolenaar
 * 08.06.2013  Little-endian hexdump (-e) and offset (-o) by Vadim Vygonets.
 * 11.01.2019  Add full 64/32 bit range to -o and output by Christer Jensen.
 * 04.02.2020  Add -d for decimal offsets by Aapo Rantalainen
 *
 * (c) 1990-1998 by Juergen Weigert (jnweiger@gmail.com)
 *
 * I hereby grant permission to distribute and use xxd
 * under X11-MIT or GPL-2.0 (at the user's choice).
 *
 * Contributions by Bram Moolenaar et al.
 */

/* Visual Studio 2005 has 'deprecated' many of the standard CRT functions */
#if _MSC_VER >= 1400
# define _CRT_SECURE_NO_DEPRECATE
# define _CRT_NONSTDC_NO_DEPRECATE
#endif
#if !defined(CYGWIN) && defined(__CYGWIN__)
# define CYGWIN
#endif

#include <stdio.h>
#ifdef VAXC
# include <file.h>
#else
# include <fcntl.h>
#endif
#if defined(WIN32) || defined(CYGWIN)
# include <io.h>	/* for setmode() */
#else
# ifdef UNIX
#  include <unistd.h>
# endif
#endif
#include <stdlib.h>
#include <string.h>	/* for strncmp() */
#include <ctype.h>	/* for isalnum() */
#include <limits.h>
#if __MWERKS__ && !defined(BEBOX)
# include <unix.h>	/* for fdopen() on MAC */
#endif


/*  This corrects the problem of missing prototypes for certain functions
 *  in some GNU installations (e.g. SunOS 4.1.x).
 *  Darren Hiebert <darren@hmi.com> (sparc-sun-sunos4.1.3_U1/2.7.2.2)
 */
#if defined(__GNUC__) && defined(__STDC__)
# ifndef __USE_FIXED_PROTOTYPES__
#  define __USE_FIXED_PROTOTYPES__
# endif
#endif

#ifndef __USE_FIXED_PROTOTYPES__
/*
 * This is historic and works only if the compiler really has no prototypes:
 *
 * Include prototypes for Sun OS 4.x, when using an ANSI compiler.
 * FILE is defined on OS 4.x, not on 5.x (Solaris).
 * if __SVR4 is defined (some Solaris versions), don't include this.
 */
#if defined(sun) && defined(FILE) && !defined(__SVR4) && defined(__STDC__)
#  define __P(a) a
/* excerpt from my sun_stdlib.h */
extern int fprintf __P((FILE *, char *, ...));
extern int fputs   __P((char *, FILE *));
extern int _flsbuf __P((unsigned char, FILE *));
extern int _filbuf __P((FILE *));
extern int fflush  __P((FILE *));
extern int fclose  __P((FILE *));
extern int fseek   __P((FILE *, long, int));
extern int rewind  __P((FILE *));

extern void perror __P((char *));
# endif
#endif

extern long int strtol();
extern long int ftell();

char version[] = "xxd 2021-10-22 by Juergen Weigert et al.";
#ifdef WIN32
char osver[] = " (Win32)";
#else
char osver[] = "";
#endif

#if defined(WIN32)
# define BIN_READ(yes)  ((yes) ? "rb" : "rt")
# define BIN_WRITE(yes) ((yes) ? "wb" : "wt")
# define BIN_CREAT(yes) ((yes) ? (O_CREAT|O_BINARY) : O_CREAT)
# define BIN_ASSIGN(fp, yes) setmode(fileno(fp), (yes) ? O_BINARY : O_TEXT)
# define PATH_SEP '\\'
#elif defined(CYGWIN)
# define BIN_READ(yes)  ((yes) ? "rb" : "rt")
# define BIN_WRITE(yes) ((yes) ? "wb" : "w")
# define BIN_CREAT(yes) ((yes) ? (O_CREAT|O_BINARY) : O_CREAT)
# define BIN_ASSIGN(fp, yes) ((yes) ? (void) setmode(fileno(fp), O_BINARY) : (void) (fp))
# define PATH_SEP '/'
#else
# ifdef VMS
#  define BIN_READ(dummy)  "r"
#  define BIN_WRITE(dummy) "w"
#  define BIN_CREAT(dummy) O_CREAT
#  define BIN_ASSIGN(fp, dummy) fp
#  define PATH_SEP ']'
#  define FILE_SEP '.'
# else
#  define BIN_READ(dummy)  "r"
#  define BIN_WRITE(dummy) "w"
#  define BIN_CREAT(dummy) O_CREAT
#  define BIN_ASSIGN(fp, dummy) fp
#  define PATH_SEP '/'
# endif
#endif

/* open has only to arguments on the Mac */
#if __MWERKS__
# define OPEN(name, mode, umask) open(name, mode)
#else
# define OPEN(name, mode, umask) open(name, mode, umask)
#endif

#ifdef AMIGA
# define STRNCMP(s1, s2, l) strncmp(s1, s2, (size_t)l)
#else
# define STRNCMP(s1, s2, l) strncmp(s1, s2, l)
#endif

#ifndef __P
# if defined(__STDC__) || defined(WIN32)
#  define __P(a) a
# else
#  define __P(a) ()
# endif
#endif

#define TRY_SEEK	/* attempt to use lseek, or skip forward by reading */
#define COLS 256	/* change here, if you ever need more columns */
#define LLEN ((2*(int)sizeof(unsigned long)) + 4 + (9*COLS-1) + COLS + 2)

char hexxa[] = "0123456789abcdef0123456789ABCDEF", *hexx = hexxa;

/* the different hextypes known by this program: */
#define HEX_NORMAL 0
#define HEX_POSTSCRIPT 1
#define HEX_CINCLUDE 2
#define HEX_BITS 3		/* not hex a dump, but bits: 01111001 */
#define HEX_LITTLEENDIAN 4

#define CONDITIONAL_CAPITALIZE(c) (capitalize ? toupper((int)c) : c)

static char *pname;

  static void
exit_with_usage(void)
{
  fprintf(stderr, "Usage:\n       %s [options] [infile [outfile]]\n", pname);
  fprintf(stderr, "    or\n       %s -r [-s [-]offset] [-c cols] [-ps] [infile [outfile]]\n", pname);
  fprintf(stderr, "Options:\n");
  fprintf(stderr, "    -a          toggle autoskip: A single '*' replaces nul-lines. Default off.\n");
  fprintf(stderr, "    -b          binary digit dump (incompatible with -ps,-i,-r). Default hex.\n");
  fprintf(stderr, "    -C          capitalize variable names in C include file style (-i).\n");
  fprintf(stderr, "    -c cols     format <cols> octets per line. Default 16 (-i: 12, -ps: 30).\n");
  fprintf(stderr, "    -E          show characters in EBCDIC. Default ASCII.\n");
  fprintf(stderr, "    -e          little-endian dump (incompatible with -ps,-i,-r).\n");
  fprintf(stderr, "    -g bytes    number of octets per group in normal output. Default 2 (-e: 4).\n");
  fprintf(stderr, "    -h          print this summary.\n");
  fprintf(stderr, "    -i          output in C include file style.\n");
  fprintf(stderr, "    -l len      stop after <len> octets.\n");
  fprintf(stderr, "    -o off      add <off> to the displayed file position.\n");
  fprintf(stderr, "    -ps         output in postscript plain hexdump style.\n");
  fprintf(stderr, "    -r          reverse operation: convert (or patch) hexdump into binary.\n");
  fprintf(stderr, "    -r -s off   revert with <off> added to file positions found in hexdump.\n");
  fprintf(stderr, "    -d          show offset in decimal instead of hex.\n");
  fprintf(stderr, "    -s %sseek  start at <seek> bytes abs. %sinfile offset.\n",
#ifdef TRY_SEEK
	  "[+][-]", "(or +: rel.) ");
#else
	  "", "");
#endif
  fprintf(stderr, "    -u          use upper case hex letters.\n");
  fprintf(stderr, "    -v          show version: \"%s%s\".\n", version, osver);
  exit(1);
}

  static void
perror_exit(int ret)
{
  fprintf(stderr, "%s: ", pname);
  perror(NULL);
  exit(ret);
}

  static void
error_exit(int ret, char *msg)
{
  fprintf(stderr, "%s: %s\n", pname, msg);
  exit(ret);
}

  static void
exit_on_ferror(char c, FILE *fpi)
{
  if (c == EOF && ferror(fpi))
    perror_exit(2);
}

  static void
putc_or_die(char c, FILE *fpo)
{
  if (putc(c, fpo) == EOF)
    perror_exit(3);
}

  static void
fputs_or_die(char *s, FILE *fpo)
{
  if (fputs(s, fpo) == EOF)
    perror_exit(3);
}

  static void
fprintf_or_die(FILE *fpo, char *format, char *s, int d)
{
  if (fprintf(fpo, format, s, d) < 0)
    perror_exit(3);
}

  static void
fclose_or_die(FILE *fpi, FILE *fpo)
{
  if (fclose(fpo) != 0)
    perror_exit(3);
  if (fclose(fpi) != 0)
    perror_exit(2);
}

/*
 * If "c" is a hex digit, return the value.
 * Otherwise return -1.
 */
  static int
parse_hex_digit(int c)
{
  return (c >= '0' && c <= '9') ? c - '0'
	: (c >= 'a' && c <= 'f') ? c - 'a' + 10
	: (c >= 'A' && c <= 'F') ? c - 'A' + 10
	: -1;
}

/*
 * Ignore text on "fpi" until end-of-line or end-of-file.
 * Return the '\n' or EOF character.
 * When an error is encountered exit with an error message.
 */
  static int
skip_to_eol(FILE *fpi, int c)
{
  while (c != '\n' && c != EOF)
    c = getc(fpi);
  exit_on_ferror(c, fpi);
  return c;
}

/*
 * Max. cols binary characters are decoded from the input stream per line.
 * Two adjacent garbage characters after evaluated data delimit valid data.
 * Everything up to the next newline is discarded.
 *
 * The name is historic and came from 'undo type opt h'.
 */
  static int
huntype(
  FILE *fpi,
  FILE *fpo,
  int cols,
  int hextype,
  long base_off)
{
  int c, ign_garb = 1, n1 = -1, n2 = 0, n3, p = cols;
  long have_off = 0, want_off = 0;

  rewind(fpi);

  while ((c = getc(fpi)) != EOF)
    {
      if (c == '\r')	/* Doze style input file? */
	continue;

      /* Allow multiple spaces.  This doesn't work when there is normal text
       * after the hex codes in the last line that looks like hex, thus only
       * use it for PostScript format. */
      if (hextype == HEX_POSTSCRIPT && (c == ' ' || c == '\n' || c == '\t'))
	continue;

      n3 = n2;
      n2 = n1;

      n1 = parse_hex_digit(c);
      if (n1 == -1 && ign_garb)
	continue;

      ign_garb = 0;

      if (!hextype && (p >= cols))
	{
	  if (n1 < 0)
	    {
	      p = 0;
	      continue;
	    }
	  want_off = (want_off << 4) | n1;
	  continue;
	}

      if (base_off + want_off != have_off)
	{
	  if (fflush(fpo) != 0)
	    perror_exit(3);
#ifdef TRY_SEEK
	  if (fseek(fpo, base_off + want_off - have_off, SEEK_CUR) >= 0)
	    have_off = base_off + want_off;
#endif
	  if (base_off + want_off < have_off)
	    error_exit(5, "sorry, cannot seek backwards.");
	  for (; have_off < base_off + want_off; have_off++)
	    putc_or_die(0, fpo);
	}

      if (n2 >= 0 && n1 >= 0)
	{
	  putc_or_die((n2 << 4) | n1, fpo);
	  have_off++;
	  want_off++;
	  n1 = -1;
	  if (!hextype && (++p >= cols))
	    /* skip the rest of the line as garbage */
	    c = skip_to_eol(fpi, c);
	}
      else if (n1 < 0 && n2 < 0 && n3 < 0)
        /* already stumbled into garbage, skip line, wait and see */
	c = skip_to_eol(fpi, c);

      if (c == '\n')
	{
	  if (!hextype)
	    want_off = 0;
	  p = cols;
	  ign_garb = 1;
	}
    }
  if (fflush(fpo) != 0)
    perror_exit(3);
#ifdef TRY_SEEK
  fseek(fpo, 0L, SEEK_END);
#endif
  fclose_or_die(fpi, fpo);
  return 0;
}

/*
 * Print line l. If nz is false, xxdline regards the line a line of
 * zeroes. If there are three or more consecutive lines of zeroes,
 * they are replaced by a single '*' character.
 *
 * If the output ends with more than two lines of zeroes, you
 * should call xxdline again with l being the last line and nz
 * negative. This ensures that the last line is shown even when
 * it is all zeroes.
 *
 * If nz is always positive, lines are never suppressed.
 */
  static void
xxdline(FILE *fp, char *l, int nz)
{
  static char z[LLEN+1];
  static int zero_seen = 0;

  if (!nz && zero_seen == 1)
    strcpy(z, l);

  if (nz || !zero_seen++)
    {
      if (nz)
	{
	  if (nz < 0)
	    zero_seen--;
	  if (zero_seen == 2)
	    fputs_or_die(z, fp);
	  if (zero_seen > 2)
	    fputs_or_die("*\n", fp);
	}
      if (nz >= 0 || zero_seen > 0)
	fputs_or_die(l, fp);
      if (nz)
	zero_seen = 0;
    }
}

/* This is an EBCDIC to ASCII conversion table */
/* from a proposed BTL standard April 16, 1979 */
static unsigned char etoa64[] =
{
    0040,0240,0241,0242,0243,0244,0245,0246,
    0247,0250,0325,0056,0074,0050,0053,0174,
    0046,0251,0252,0253,0254,0255,0256,0257,
    0260,0261,0041,0044,0052,0051,0073,0176,
    0055,0057,0262,0263,0264,0265,0266,0267,
    0270,0271,0313,0054,0045,0137,0076,0077,
    0272,0273,0274,0275,0276,0277,0300,0301,
    0302,0140,0072,0043,0100,0047,0075,0042,
    0303,0141,0142,0143,0144,0145,0146,0147,
    0150,0151,0304,0305,0306,0307,0310,0311,
    0312,0152,0153,0154,0155,0156,0157,0160,
    0161,0162,0136,0314,0315,0316,0317,0320,
    0321,0345,0163,0164,0165,0166,0167,0170,
    0171,0172,0322,0323,0324,0133,0326,0327,
    0330,0331,0332,0333,0334,0335,0336,0337,
    0340,0341,0342,0343,0344,0135,0346,0347,
    0173,0101,0102,0103,0104,0105,0106,0107,
    0110,0111,0350,0351,0352,0353,0354,0355,
    0175,0112,0113,0114,0115,0116,0117,0120,
    0121,0122,0356,0357,0360,0361,0362,0363,
    0134,0237,0123,0124,0125,0126,0127,0130,
    0131,0132,0364,0365,0366,0367,0370,0371,
    0060,0061,0062,0063,0064,0065,0066,0067,
    0070,0071,0372,0373,0374,0375,0376,0377
};

  int
main(int argc, char *argv[])
{
  FILE *fp, *fpo;
  int c, e, p = 0, relseek = 1, negseek = 0, revert = 0;
  int cols = 0, nonzero = 0, autoskip = 0, hextype = HEX_NORMAL;
  int capitalize = 0, decimal_offset = 0;
  int ebcdic = 0;
  int octspergrp = -1;	/* number of octets grouped in output */
  int grplen;		/* total chars per octet group */
  long length = -1, n = 0, seekoff = 0;
  unsigned long displayoff = 0;
  static char l[LLEN+1];  /* static because it may be too big for stack */
  char *pp;
  int addrlen = 9;

#ifdef AMIGA
  /* This program doesn't work when started from the Workbench */
  if (argc == 0)
    exit(1);
#endif

  pname = argv[0];
  for (pp = pname; *pp; )
    if (*pp++ == PATH_SEP)
      pname = pp;
#ifdef FILE_SEP
  for (pp = pname; *pp; pp++)
    if (*pp == FILE_SEP)
      {
	*pp = '\0';
	break;
      }
#endif

  while (argc >= 2)
    {
      pp = argv[1] + (!STRNCMP(argv[1], "--", 2) && argv[1][2]);
	   if (!STRNCMP(pp, "-a", 2)) autoskip = 1 - autoskip;
      else if (!STRNCMP(pp, "-b", 2)) hextype = HEX_BITS;
      else if (!STRNCMP(pp, "-e", 2)) hextype = HEX_LITTLEENDIAN;
      else if (!STRNCMP(pp, "-u", 2)) hexx = hexxa + 16;
      else if (!STRNCMP(pp, "-p", 2)) hextype = HEX_POSTSCRIPT;
      else if (!STRNCMP(pp, "-i", 2)) hextype = HEX_CINCLUDE;
      else if (!STRNCMP(pp, "-C", 2)) capitalize = 1;
      else if (!STRNCMP(pp, "-d", 2)) decimal_offset = 1;
      else if (!STRNCMP(pp, "-r", 2)) revert++;
      else if (!STRNCMP(pp, "-E", 2)) ebcdic++;
      else if (!STRNCMP(pp, "-v", 2))
	{
	  fprintf(stderr, "%s%s\n", version, osver);
	  exit(0);
	}
      else if (!STRNCMP(pp, "-c", 2))
	{
	  if (pp[2] && !STRNCMP("apitalize", pp + 2, 9))
	    capitalize = 1;
	  else if (pp[2] && STRNCMP("ols", pp + 2, 3))
	    cols = (int)strtol(pp + 2, NULL, 0);
	  else
	    {
	      if (!argv[2])
		exit_with_usage();
	      cols = (int)strtol(argv[2], NULL, 0);
	      argv++;
	      argc--;
	    }
	}
      else if (!STRNCMP(pp, "-g", 2))
	{
	  if (pp[2] && STRNCMP("roup", pp + 2, 4))
	    octspergrp = (int)strtol(pp + 2, NULL, 0);
	  else
	    {
	      if (!argv[2])
		exit_with_usage();
	      octspergrp = (int)strtol(argv[2], NULL, 0);
	      argv++;
	      argc--;
	    }
	}
      else if (!STRNCMP(pp, "-o", 2))
	{
	  int reloffset = 0;
	  int negoffset = 0;
	  if (pp[2] && STRNCMP("ffset", pp + 2, 5))
	    displayoff = strtoul(pp + 2, NULL, 0);
	  else
	    {
	      if (!argv[2])
		exit_with_usage();

	      if (argv[2][0] == '+')
	       reloffset++;
	     if (argv[2][reloffset] == '-')
	       negoffset++;

	     if (negoffset)
	       displayoff = ULONG_MAX - strtoul(argv[2] + reloffset+negoffset, NULL, 0) + 1;
	     else
	       displayoff = strtoul(argv[2] + reloffset+negoffset, NULL, 0);

	      argv++;
	      argc--;
	    }
	}
      else if (!STRNCMP(pp, "-s", 2))
	{
	  relseek = 0;
	  negseek = 0;
	  if (pp[2] && STRNCMP("kip", pp+2, 3) && STRNCMP("eek", pp+2, 3))
	    {
#ifdef TRY_SEEK
	      if (pp[2] == '+')
		relseek++;
	      if (pp[2+relseek] == '-')
		negseek++;
#endif
	      seekoff = strtol(pp + 2+relseek+negseek, (char **)NULL, 0);
	    }
	  else
	    {
	      if (!argv[2])
		exit_with_usage();
#ifdef TRY_SEEK
	      if (argv[2][0] == '+')
		relseek++;
	      if (argv[2][relseek] == '-')
		negseek++;
#endif
	      seekoff = strtol(argv[2] + relseek+negseek, (char **)NULL, 0);
	      argv++;
	      argc--;
	    }
	}
      else if (!STRNCMP(pp, "-l", 2))
	{
	  if (pp[2] && STRNCMP("en", pp + 2, 2))
	    length = strtol(pp + 2, (char **)NULL, 0);
	  else
	    {
	      if (!argv[2])
		exit_with_usage();
	      length = strtol(argv[2], (char **)NULL, 0);
	      argv++;
	      argc--;
	    }
	}
      else if (!strcmp(pp, "--"))	/* end of options */
	{
	  argv++;
	  argc--;
	  break;
	}
      else if (pp[0] == '-' && pp[1])	/* unknown option */
	exit_with_usage();
      else
	break;				/* not an option */

      argv++;				/* advance to next argument */
      argc--;
    }

  if (!cols)
    switch (hextype)
      {
      case HEX_POSTSCRIPT:	cols = 30; break;
      case HEX_CINCLUDE:	cols = 12; break;
      case HEX_BITS:		cols = 6; break;
      case HEX_NORMAL:
      case HEX_LITTLEENDIAN:
      default:			cols = 16; break;
      }

  if (octspergrp < 0)
    switch (hextype)
      {
      case HEX_BITS:		octspergrp = 1; break;
      case HEX_NORMAL:		octspergrp = 2; break;
      case HEX_LITTLEENDIAN:	octspergrp = 4; break;
      case HEX_POSTSCRIPT:
      case HEX_CINCLUDE:
      default:			octspergrp = 0; break;
      }

  if (cols < 1 || ((hextype == HEX_NORMAL || hextype == HEX_BITS || hextype == HEX_LITTLEENDIAN)
							    && (cols > COLS)))
    {
      fprintf(stderr, "%s: invalid number of columns (max. %d).\n", pname, COLS);
      exit(1);
    }

  if (octspergrp < 1 || octspergrp > cols)
    octspergrp = cols;
  else if (hextype == HEX_LITTLEENDIAN && (octspergrp & (octspergrp-1)))
    error_exit(1, "number of octets per group must be a power of 2 with -e.");

  if (argc > 3)
    exit_with_usage();

  if (argc == 1 || (argv[1][0] == '-' && !argv[1][1]))
    BIN_ASSIGN(fp = stdin, !revert);
  else
    {
      if ((fp = fopen(argv[1], BIN_READ(!revert))) == NULL)
	{
	  fprintf(stderr,"%s: ", pname);
	  perror(argv[1]);
	  return 2;
	}
    }

  if (argc < 3 || (argv[2][0] == '-' && !argv[2][1]))
    BIN_ASSIGN(fpo = stdout, revert);
  else
    {
      int fd;
      int mode = revert ? O_WRONLY : (O_TRUNC|O_WRONLY);

      if (((fd = OPEN(argv[2], mode | BIN_CREAT(revert), 0666)) < 0) ||
	  (fpo = fdopen(fd, BIN_WRITE(revert))) == NULL)
	{
	  fprintf(stderr, "%s: ", pname);
	  perror(argv[2]);
	  return 3;
	}
      rewind(fpo);
    }

  if (revert)
    {
      if (hextype && (hextype != HEX_POSTSCRIPT))
	error_exit(-1, "sorry, cannot revert this type of hexdump");
      return huntype(fp, fpo, cols, hextype,
		negseek ? -seekoff : seekoff);
    }

  if (seekoff || negseek || !relseek)
    {
#ifdef TRY_SEEK
      if (relseek)
	e = fseek(fp, negseek ? -seekoff : seekoff, SEEK_CUR);
      else
	e = fseek(fp, negseek ? -seekoff : seekoff,
						negseek ? SEEK_END : SEEK_SET);
      if (e < 0 && negseek)
	error_exit(4, "sorry cannot seek.");
      if (e >= 0)
	seekoff = ftell(fp);
      else
#endif
	{
	  long s = seekoff;

	  while (s--)
	    if ((c = getc(fp)) == EOF)
	    {
	      exit_on_ferror(c, fp);
	      error_exit(4, "sorry cannot seek.");
	    }
	}
    }

  if (hextype == HEX_CINCLUDE)
    {
      if (fp != stdin)
	{
	  fprintf_or_die(fpo, "unsigned char %s", isdigit((int)argv[1][0]) ? "__" : "", 0);
	  for (e = 0; (c = argv[1][e]) != 0; e++)
	    putc_or_die(isalnum(c) ? CONDITIONAL_CAPITALIZE(c) : '_', fpo);
	  fputs_or_die("[] = {\n", fpo);
	}

      p = 0;
      c = 0;
      while ((length < 0 || p < length) && (c = getc(fp)) != EOF)
	{
	  fprintf_or_die(fpo, (hexx == hexxa) ? "%s0x%02x" : "%s0X%02X",
		(p % cols) ? ", " : &",\n  "[2*!p],  c);
	  p++;
	}
      exit_on_ferror(c, fp);

      if (p)
	fputs_or_die("\n", fpo);
      fputs_or_die(&"};\n"[3 * (fp == stdin)], fpo);

      if (fp != stdin)
	{
	  fprintf_or_die(fpo, "unsigned int %s", isdigit((int)argv[1][0]) ? "__" : "", 0);
	  for (e = 0; (c = argv[1][e]) != 0; e++)
	    putc_or_die(isalnum(c) ? CONDITIONAL_CAPITALIZE(c) : '_', fpo);
	  fprintf_or_die(fpo, "_%s = %d;\n", capitalize ? "LEN" : "len", p);
	}

      fclose_or_die(fp, fpo);
      return 0;
    }

  if (hextype == HEX_POSTSCRIPT)
    {
      p = cols;
      e = 0;
      while ((length < 0 || n < length) && (e = getc(fp)) != EOF)
	{
	  putc_or_die(hexx[(e >> 4) & 0xf], fpo);
	  putc_or_die(hexx[e & 0xf], fpo);
	  n++;
	  if (!--p)
	    {
	      putc_or_die('\n', fpo);
	      p = cols;
	    }
	}
      exit_on_ferror(e, fp);
      if (p < cols)
	putc_or_die('\n', fpo);
      fclose_or_die(fp, fpo);
      return 0;
    }

  /* hextype: HEX_NORMAL or HEX_BITS or HEX_LITTLEENDIAN */

  if (hextype != HEX_BITS)
    grplen = octspergrp + octspergrp + 1;	/* chars per octet group */
  else	/* hextype == HEX_BITS */
    grplen = 8 * octspergrp + 1;

  e = 0;
  while ((length < 0 || n < length) && (e = getc(fp)) != EOF)
    {
      int x;

      if (p == 0)
	{
	  addrlen = sprintf(l, decimal_offset ? "%08ld:" : "%08lx:",
				  ((unsigned long)(n + seekoff + displayoff)));
	  for (c = addrlen; c < LLEN; l[c++] = ' ');
	}
      x = hextype == HEX_LITTLEENDIAN ? p ^ (octspergrp-1) : p;
      c = addrlen + 1 + (grplen * x) / octspergrp;
      if (hextype == HEX_NORMAL || hextype == HEX_LITTLEENDIAN)
	{
	  l[c]   = hexx[(e >> 4) & 0xf];
	  l[++c] = hexx[e & 0xf];
	}
      else /* hextype == HEX_BITS */
	{
	  int i;
	  for (i = 7; i >= 0; i--)
	    l[c++] = (e & (1 << i)) ? '1' : '0';
	}
      if (e)
	nonzero++;
      if (ebcdic)
	e = (e < 64) ? '.' : etoa64[e-64];
      /* When changing this update definition of LLEN above. */
      c = addrlen + 3 + (grplen * cols - 1)/octspergrp + p;
      l[c++] =
#ifdef __MVS__
	  (e >= 64)
#else
	  (e > 31 && e < 127)
#endif
	  ? e : '.';
      n++;
      if (++p == cols)
	{
	  l[c] = '\n';
	  l[++c] = '\0';
	  xxdline(fpo, l, autoskip ? nonzero : 1);
	  nonzero = 0;
	  p = 0;
	}
    }
  exit_on_ferror(e, fp);
  if (p)
    {
      l[c] = '\n';
      l[++c] = '\0';
      xxdline(fpo, l, 1);
    }
  else if (autoskip)
    xxdline(fpo, l, -1);	/* last chance to flush out suppressed lines */

  fclose_or_die(fp, fpo);
  return 0;
}

/* vi:set ts=8 sw=4 sts=2 cino+={2 cino+=n-2 : */