From 77e00dbff29bb84ca1625007d722e38a00e6f601 Mon Sep 17 00:00:00 2001
From: jtc <jtc@NetBSD.org>
Date: Fri, 21 Oct 1994 21:18:45 +0000
Subject: random(6), from 44lite

---
 random/random.c | 148 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 148 insertions(+)
 create mode 100644 random/random.c

(limited to 'random/random.c')

diff --git a/random/random.c b/random/random.c
new file mode 100644
index 00000000..a6fe4725
--- /dev/null
+++ b/random/random.c
@@ -0,0 +1,148 @@
+/*
+ * 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. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. 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.
+ */
+
+#ifndef lint
+static char copyright[] =
+"@(#) Copyright (c) 1994\n\
+	The Regents of the University of California.  All rights reserved.\n";
+#endif /* not lint */
+
+#ifndef lint
+static char sccsid[] = "@(#)random.c	8.5 (Berkeley) 4/5/94";
+#endif /* not lint */
+
+#include <sys/types.h>
+
+#include <err.h>
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+#include <unistd.h>
+
+void usage __P((void));
+
+int
+main(argc, argv)
+	int argc;
+	char *argv[];
+{
+	extern int optind;
+	time_t now;
+	double denom;
+	int ch, random_exit, selected, unbuffer_output;
+	char *ep;
+
+	random_exit = unbuffer_output = 0;
+	while ((ch = getopt(argc, argv, "er")) != EOF)
+		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)time(&now);
+	srandom((u_int)(now + getpid()));
+
+	/* Compute a random exit status between 0 and denom - 1. */
+	if (random_exit)
+		return ((denom * random()) / LONG_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() / LONG_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() / LONG_MAX) == 0;
+		}
+	}
+	if (ferror(stdin))
+		err(2, "stdin");
+	exit (0);
+}
+
+void
+usage()
+{
+
+	(void)fprintf(stderr, "usage: random [-er] [denominator]\n");
+	exit(1);
+}
-- 
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