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 39 #include <sys/cdefs.h> 40 #ifndef lint 41 __COPYRIGHT("@(#) Copyright (c) 1988, 1993\ 42 The Regents of the University of California. All rights reserved."); 43 #endif /* not lint */ 44 45 #ifndef lint 46 #if 0 47 static char sccsid[] = "@(#)ching.cno.c 8.1 (Berkeley) 5/31/93"; 48 #else 49 __RCSID("$NetBSD: castching.c,v 1.3 2009/08/12 05:40:03 dholland 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 63 static time_t now; /* current time */ 64 65 static unsigned seed; /* seed for random number generator */ 66 67 static int getquest(void); 68 static unsigned getrand(void); 69 static unsigned getrnum(void); 70 static char *change(void); 71 72 static char string[6+1]; /* where the actual change string is put */ 73 74 static int table[2][2][2] = { 75 { { OYIN, YYANG,}, { YYANG, YYIN,} }, 76 { { YYANG, YYIN,}, { YYIN, OYANG,} }, 77 }; 78 79 /*ARGSUSED*/ 80 int 81 main(int argc, char **argv) 82 { 83 time(&now); 84 /* randomize */ 85 seed = (int)now + getquest() + getgid() + getuid() + getpid(); 86 printf("%s\n", change()); 87 exit(0); 88 } 89 90 /* 91 * Hash the question by adding all the characters together. 92 */ 93 static int 94 getquest(void) 95 { 96 int result; 97 int c; 98 99 result = 0; 100 while ((c = getchar()) != EOF) 101 result += c; 102 return(result); 103 } 104 105 /* 106 * Get a set of six lines making up a change. 107 */ 108 static char * 109 change(void) 110 { 111 int i; 112 113 for (i = 0; i < 6; i++) 114 string[i] = table[getrnum()&01][getrnum()&01][getrnum()&01] + '0'; 115 string[i] = '\0'; 116 return(string); 117 } 118 119 /* 120 * Get a number more random than what getrand() gives. 121 */ 122 static unsigned 123 getrnum(void) 124 { 125 return((getrand())>>(getrand()%17)); 126 } 127 128 /* 129 * Get a random number. 130 */ 131 static unsigned 132 getrand(void) 133 { 134 return(seed = (seed*13077) + 6925); 135 } 136