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File: [cvs.NetBSD.org] / src / games / random / random.c (download)

Revision 1.14, Wed Aug 12 08:27:24 2009 UTC (11 years, 2 months ago) by dholland
Branch: MAIN
CVS Tags: yamt-pagecache-tag8, yamt-pagecache-base9, yamt-pagecache-base8, yamt-pagecache-base7, yamt-pagecache-base6, yamt-pagecache-base5, yamt-pagecache-base4, yamt-pagecache-base3, yamt-pagecache-base2, yamt-pagecache-base, yamt-pagecache, tls-maxphys-base, tls-maxphys, tls-earlyentropy-base, tls-earlyentropy, riastradh-xf86-video-intel-2-7-1-pre-2-21-15, riastradh-drm2-base3, riastradh-drm2-base2, riastradh-drm2-base1, riastradh-drm2-base, riastradh-drm2, prg-localcount2-base3, prg-localcount2-base2, prg-localcount2-base1, prg-localcount2-base, prg-localcount2, phil-wifi-base, phil-wifi-20200421, phil-wifi-20200411, phil-wifi-20200406, phil-wifi-20191119, phil-wifi-20190609, phil-wifi, pgoyette-localcount-base, pgoyette-localcount-20170426, pgoyette-localcount-20170320, pgoyette-localcount-20170107, pgoyette-localcount-20161104, pgoyette-localcount-20160806, pgoyette-localcount-20160726, pgoyette-localcount, pgoyette-compat-merge-20190127, pgoyette-compat-base, pgoyette-compat-20190127, pgoyette-compat-20190118, pgoyette-compat-1226, pgoyette-compat-1126, pgoyette-compat-1020, pgoyette-compat-0930, pgoyette-compat-0906, pgoyette-compat-0728, pgoyette-compat-0625, pgoyette-compat-0521, pgoyette-compat-0502, pgoyette-compat-0422, pgoyette-compat-0415, pgoyette-compat-0407, pgoyette-compat-0330, pgoyette-compat-0322, pgoyette-compat-0315, pgoyette-compat, perseant-stdc-iso10646-base, perseant-stdc-iso10646, netbsd-9-base, netbsd-9-1-RELEASE, netbsd-9-0-RELEASE, netbsd-9-0-RC2, netbsd-9-0-RC1, netbsd-9, netbsd-8-base, netbsd-8-2-RELEASE, netbsd-8-1-RELEASE, netbsd-8-1-RC1, netbsd-8-0-RELEASE, netbsd-8-0-RC2, netbsd-8-0-RC1, netbsd-8, netbsd-7-nhusb-base-20170116, netbsd-7-nhusb-base, netbsd-7-nhusb, netbsd-7-base, netbsd-7-2-RELEASE, netbsd-7-1-RELEASE, netbsd-7-1-RC2, netbsd-7-1-RC1, netbsd-7-1-2-RELEASE, netbsd-7-1-1-RELEASE, netbsd-7-1, netbsd-7-0-RELEASE, netbsd-7-0-RC3, netbsd-7-0-RC2, netbsd-7-0-RC1, netbsd-7-0-2-RELEASE, netbsd-7-0-1-RELEASE, netbsd-7-0, netbsd-7, netbsd-6-base, netbsd-6-1-RELEASE, netbsd-6-1-RC4, netbsd-6-1-RC3, netbsd-6-1-RC2, netbsd-6-1-RC1, netbsd-6-1-5-RELEASE, netbsd-6-1-4-RELEASE, netbsd-6-1-3-RELEASE, netbsd-6-1-2-RELEASE, netbsd-6-1-1-RELEASE, netbsd-6-1, netbsd-6-0-RELEASE, netbsd-6-0-RC2, netbsd-6-0-RC1, netbsd-6-0-6-RELEASE, netbsd-6-0-5-RELEASE, netbsd-6-0-4-RELEASE, netbsd-6-0-3-RELEASE, netbsd-6-0-2-RELEASE, netbsd-6-0-1-RELEASE, netbsd-6-0, netbsd-6, matt-premerge-20091211, matt-nb8-mediatek-base, matt-nb8-mediatek, matt-nb6-plus-nbase, matt-nb6-plus-base, matt-nb6-plus, matt-mips64-premerge-20101231, localcount-20160914, is-mlppp-base, is-mlppp, cherry-xenmp-base, cherry-xenmp, bouyer-socketcan-base1, bouyer-socketcan-base, bouyer-socketcan, bouyer-quota2-nbase, bouyer-quota2-base, bouyer-quota2, agc-symver-base, agc-symver
Changes since 1.13: +4 -4 lines

sprinkle static

/*	$NetBSD: random.c,v 1.14 2009/08/12 08:27:24 dholland Exp $	*/

/*
 * Copyright (c) 1994
 *	The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Guy Harris at Network Appliance Corp.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/cdefs.h>
#ifndef lint
__COPYRIGHT("@(#) Copyright (c) 1994\
 The Regents of the University of California.  All rights reserved.");
#endif /* not lint */

#ifndef lint
#if 0
static char sccsid[] = "@(#)random.c	8.6 (Berkeley) 6/1/94";
#else
__RCSID("$NetBSD: random.c,v 1.14 2009/08/12 08:27:24 dholland Exp $");
#endif
#endif /* not lint */

#include <sys/types.h>
#include <sys/time.h>

#include <err.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <unistd.h>
#include <limits.h>

static void usage(void) __dead;

int
main(int argc, char *argv[])
{
	struct timeval tp;
	double denom;
	int ch, random_exit, selected, unbuffer_output;
	char *ep;

	denom = 0;
	random_exit = unbuffer_output = 0;
	while ((ch = getopt(argc, argv, "er")) != -1)
		switch (ch) {
		case 'e':
			random_exit = 1;
			break;
		case 'r':
			unbuffer_output = 1;
			break;
		default:
		case '?':
			usage();
			/* NOTREACHED */
		}

	argc -= optind;
	argv += optind;

	switch (argc) {
	case 0:
		denom = 2;
		break;
	case 1:
		errno = 0;
		denom = strtod(*argv, &ep);
		if (errno == ERANGE)
			err(1, "%s", *argv);
		if (denom == 0 || *ep != '\0')
			errx(1, "denominator is not valid.");
		break;
	default:
		usage(); 
		/* NOTREACHED */
	}

	(void)gettimeofday(&tp, NULL);
	srandom((unsigned long)tp.tv_usec + tp.tv_sec + getpid());

	/* Compute a random exit status between 0 and denom - 1. */
	if (random_exit)
		return ((denom * random()) / RANDOM_MAX);

	/*
	 * Act as a filter, randomly choosing lines of the standard input
	 * to write to the standard output.
	 */
	if (unbuffer_output)
		setbuf(stdout, NULL);
	
	/*
	 * Select whether to print the first line.  (Prime the pump.)
	 * We find a random number between 0 and denom - 1 and, if it's
	 * 0 (which has a 1 / denom chance of being true), we select the
	 * line.
	 */
	selected = (int)(denom * random() / RANDOM_MAX) == 0;
	while ((ch = getchar()) != EOF) {
		if (selected)
			(void)putchar(ch);
		if (ch == '\n') {
			/* End of that line.  See if we got an error. */
			if (ferror(stdout))
				err(2, "stdout");

			/* Now see if the next line is to be printed. */
			selected = (int)(denom * random() / RANDOM_MAX) == 0;
		}
	}
	if (ferror(stdin))
		err(2, "stdin");
	exit (0);

	return 0;
}

static void
usage(void)
{

	(void)fprintf(stderr, "usage: random [-er] [denominator]\n");
	exit(1);
}