castching.c revision 1.1 
1/*	$NetBSD: castching.c,v 1.1 2005/06/30 13:30:33 perry Exp $	*/
2
3/*
4 * Copyright (c) 1988, 1993
5 *	The Regents of the University of California.  All rights reserved.
6 *
7 * This code is derived from software contributed to Berkeley by
8 * Guy Harris.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 *    notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in the
17 *    documentation and/or other materials provided with the distribution.
18 * 3. All advertising materials mentioning features or use of this software
19 *    must display the following acknowledgement:
20 *	This product includes software developed by the University of
21 *	California, Berkeley and its contributors.
22 * 4. Neither the name of the University nor the names of its contributors
23 *    may be used to endorse or promote products derived from this software
24 *    without specific prior written permission.
25 *
26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36 * SUCH DAMAGE.
37 */
38
39#include <sys/cdefs.h>
40#ifndef lint
41__COPYRIGHT("@(#) Copyright (c) 1988, 1993\n\
42	The Regents of the University of California.  All rights reserved.\n");
43#endif /* not lint */
44
45#ifndef lint
46#if 0
47static char sccsid[] = "@(#)ching.cno.c	8.1 (Berkeley) 5/31/93";
48#else
49__RCSID("$NetBSD: castching.c,v 1.1 2005/06/30 13:30:33 perry Exp $");
50#endif
51#endif /* not lint */
52
53/*
54 * castching - Read a question, cast a change, and output the line
55 * values to the standard output for processing by "printching".
56 */
57#include <stdio.h>
58#include <stdlib.h>
59#include <time.h>
60#include <unistd.h>
61#include "ching.h"
62
63time_t	now;		/* current time */
64
65unsigned seed;		/* seed for random number generator */
66int getquest(void);
67unsigned getrand(void);
68unsigned getrnum(void);
69char *change(void);
70
71char string[6+1];	/* where the actual change string is put */
72
73int table[2][2][2] = {
74	{ { OYIN,  YYANG,}, { YYANG, YYIN,} },
75	{ { YYANG, YYIN,},  { YYIN,  OYANG,} },
76};
77
78/*ARGSUSED*/
79int
80main(int argc, char **argv)
81{
82	time(&now);
83	/* randomize */
84	seed = (int)now + getquest() + getgid() + getuid() + getpid();
85	printf("%s\n", change());
86	exit(0);
87}
88
89/*
90 * Hash the question by adding all the characters together.
91 */
92int
93getquest(void)
94{
95	int result;
96	int c;
97
98	result = 0;
99	while ((c = getchar()) != EOF)
100		result += c;
101	return(result);
102}
103
104/*
105 * Get a set of six lines making up a change.
106 */
107char *
108change(void)
109{
110	int i;
111
112	for (i = 0; i < 6; i++)
113		string[i] = table[getrnum()&01][getrnum()&01][getrnum()&01] + '0';
114	string[i] = '\0';
115	return(string);
116}
117
118/*
119 * Get a number more random than what getrand() gives.
120 */
121unsigned
122getrnum(void)
123{
124	return((getrand())>>(getrand()%17));
125}
126
127/*
128 * Get a random number.
129 */
130unsigned
131getrand(void)
132{
133	return(seed = (seed*13077) + 6925);
134}
135