Fix bit operations. Test them (a bit) better.

[u/mdw/catacomb] / factorial.c

/* -*-c-*-
 *
 * $Id: factorial.c,v 1.3 2002/01/13 19:51:59 mdw Exp $
 *
 * Example factorial computation
 *
 * (c) 2000 Straylight/Edgeware
 */

/*----- Licensing notice --------------------------------------------------* 
 *
 * This file is part of Catacomb.
 *
 * Catacomb is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Library General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or (at your option) any later version.
 * 
 * Catacomb is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Library General Public License for more details.
 * 
 * You should have received a copy of the GNU Library General Public
 * License along with Catacomb; if not, write to the Free
 * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
 * MA 02111-1307, USA.
 */

/*----- Revision history --------------------------------------------------* 
 *
 * $Log: factorial.c,v $
 * Revision 1.3  2002/01/13 19:51:59  mdw
 * Provide proper help and options parsing.  Allow more bases.  Use
 * @mptext@ to read integers for the better base support.
 *
 * Revision 1.2  2001/06/16 13:22:59  mdw
 * Added command-line option to select output radix.
 *
 * Revision 1.1  2000/07/09 21:30:49  mdw
 * Demo program to compute factorials.
 *
 */

/*----- Header files ------------------------------------------------------*/

#include "config.h"

#include <ctype.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>

#include <mLib/mdwopt.h>
#include <mLib/quis.h>
#include <mLib/report.h>

#include "mpint.h"
#include "mpmul.h"
#include "mptext.h"

/*----- Main code ---------------------------------------------------------*/

static void usage(FILE *fp)
{
  pquis(fp, "Usage: $ [-r radix] integer\n");
}

static void version(FILE *fp)
{
  pquis(fp, "$, Catacomb version " VERSION "\n");
}

static void help(FILE *fp)
{
  version(fp);
  putc('\n', fp);
  usage(fp);
  fputs("\n\
Prints the factorial of the given integer on its output.  Input may be\n\
in decimal (the default), octal with preceding zero, hex with preceding\n\
`0x', or any base N between 2 and 62 inclusive with preceding `N_'.\n\
Output may be in any base between 2 and 62; the default is base 10.  For\n\
bases between 11 and 36 inclusive, lowercase letters of either case are\n\
used as additional digits with values 10 upwards; lowercase is always\n\
used for output.  For bases between 37 and 62 inclusive, lowercase letters\n\
have lower value than uppercase; hence `a' has the value 10, while `A' has\n\
the value 36.\n\
\n\
Options provided:\n\
\n\
-h, --help		Display this help message.\n\
-v, --version		Display the version number.\n\
-u, --usage		Display a usage message.\n\
\n\
-r, --radix=N		Write output in base N.\n\
", fp);
}

int main(int argc, char *argv[])
{
  unsigned long x;
  int r = 10;
  char *p;
  mp *f, *ulmax, *xx;
  unsigned fl = 0;

#define f_bogus 1u

  ego(argv[0]);

  for (;;) {
    static const struct option opt[] = {
      { "help",		0,		0,	'h' },
      { "version",	0,		0,	'v' },
      { "usage",	0,		0,	'u' },
      { "radix",	OPTF_ARGREQ,	0,	'r' },
      { 0,		0,		0,	0 }
    };
    int i = mdwopt(argc, argv, "hvur:", opt, 0, 0, 0);
    if (i < 0)
      break;
    switch (i) {
      case 'h':
	help(stdout);
	exit(0);
      case 'v':
	version(stdout);
	exit(0);
      case 'u':
	usage(stdout);
	exit(0);
      case 'r':
	r = atoi(optarg);
	if (r < 2 || r > 62)
	  die(EXIT_FAILURE, "bad radix `%s'", optarg);
	break;
      default:
	fl |= f_bogus;
	break;
    }
  }

  if (optind + 1 != argc || (fl & f_bogus)) {
    usage(stderr);
    exit(EXIT_FAILURE);
  }
  ulmax = mp_fromulong(MP_NEW, ULONG_MAX);
  p = argv[optind];
  while (isspace((unsigned char)*p))
    p++;
  xx = mp_readstring(MP_NEW, argv[optind], &p, 0);
  while (isspace((unsigned char)*p))
    p++;
  if (!xx || *p || MP_CMP(xx, >, ulmax))
    die(EXIT_FAILURE, "bad integer `%s'", argv[optind]);
  x = mp_toulong(xx);
  mp_drop(xx);
  mp_drop(ulmax);
  f = mp_factorial(x);
  mp_writefile(f, stdout, r);
  fputc('\n', stdout);
  mp_drop(f);
  return (0);
}

/*----- That's all, folks -------------------------------------------------*/