1 /* $NetBSD: castching.c,v 1.3 2009/08/12 05:40:03 dholland 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 * @(#)ching.cno.c 8.1 (Berkeley) 5/31/93 39 */ 40 41 /* 42 * castching - Read a question, cast a change, and output the line 43 * values to the standard output for processing by "printching". 44 */ 45 #include <stdio.h> 46 #include <stdlib.h> 47 #include <time.h> 48 #include <unistd.h> 49 #include "ching.h" 50 51 static time_t now; /* current time */ 52 53 static unsigned seed; /* seed for random number generator */ 54 55 static int getquest(void); 56 static unsigned getrand(void); 57 static unsigned getrnum(void); 58 static char *change(void); 59 60 static char string[6+1]; /* where the actual change string is put */ 61 62 static int table[2][2][2] = { 63 { { OYIN, YYANG,}, { YYANG, YYIN,} }, 64 { { YYANG, YYIN,}, { YYIN, OYANG,} }, 65 }; 66 67 int 68 main(void) 69 { 70 time(&now); 71 /* randomize */ 72 seed = (int)now + getquest() + getgid() + getuid() + getpid(); 73 printf("%s\n", change()); 74 exit(0); 75 } 76 77 /* 78 * Hash the question by adding all the characters together. 79 */ 80 static int 81 getquest(void) 82 { 83 int result; 84 int c; 85 86 result = 0; 87 while ((c = getchar()) != EOF) 88 result += c; 89 return(result); 90 } 91 92 /* 93 * Get a set of six lines making up a change. 94 */ 95 static char * 96 change(void) 97 { 98 int i; 99 100 for (i = 0; i < 6; i++) 101 string[i] = table[getrnum()&01][getrnum()&01][getrnum()&01] + '0'; 102 string[i] = '\0'; 103 return(string); 104 } 105 106 /* 107 * Get a number more random than what getrand() gives. 108 */ 109 static unsigned 110 getrnum(void) 111 { 112 return((getrand())>>(getrand()%17)); 113 } 114 115 /* 116 * Get a random number. 117 */ 118 static unsigned 119 getrand(void) 120 { 121 return(seed = (seed*13077) + 6925); 122 } 123