1 /*	$NetBSD: odds.c,v 1.4 1997/10/10 08:59:46 lukem Exp $	*/
2 
3 /*
4  * Copyright (c) 1980, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. All advertising materials mentioning features or use of this software
16  *    must display the following acknowledgement:
17  *	This product includes software developed by the University of
18  *	California, Berkeley and its contributors.
19  * 4. Neither the name of the University nor the names of its contributors
20  *    may be used to endorse or promote products derived from this software
21  *    without specific prior written permission.
22  *
23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33  * SUCH DAMAGE.
34  */
35 
36 #include <sys/cdefs.h>
37 #ifndef lint
38 #if 0
39 static char sccsid[] = "@(#)odds.c	8.1 (Berkeley) 5/31/93";
40 #else
41 __RCSID("$NetBSD: odds.c,v 1.4 1997/10/10 08:59:46 lukem Exp $");
42 #endif
43 #endif /* not lint */
44 
45 #include "back.h"
46 
47 void
48 odds(r1, r2, val)
49 	int     r1, r2, val;
50 {
51 	int     i, j;
52 
53 	if (r1 == 0) {
54 		for (i = 0; i < 6; i++)
55 			for (j = 0; j < 6; j++)
56 				table[i][j] = 0;
57 		return;
58 	} else {
59 		r1--;
60 		if (r2-- == 0) {
61 			for (i = 0; i < 6; i++) {
62 				table[i][r1] += val;
63 				table[r1][i] += val;
64 			}
65 		} else {
66 			table[r2][r1] += val;
67 			table[r1][r2] += val;
68 		}
69 	}
70 }
71 
72 int
73 count()
74 {
75 	int     i;
76 	int     j;
77 	int     total;
78 
79 	total = 0;
80 	for (i = 0; i < 6; i++)
81 		for (j = 0; j < 6; j++)
82 			total += table[i][j];
83 	return (total);
84 }
85 
86 int
87 canhit(i, c)
88 	int     i, c;
89 {
90 	int     j, k, b;
91 	int     a, diff, place, addon, menstuck;
92 
93 	if (c == 0)
94 		odds(0, 0, 0);
95 	if (board[i] > 0) {
96 		a = -1;
97 		b = 25;
98 	} else {
99 		a = 1;
100 		b = 0;
101 	}
102 	place = abs(25 - b - i);
103 	menstuck = abs(board[b]);
104 	for (j = b; j != i; j += a) {
105 		if (board[j] * a > 0) {
106 			diff = abs(j - i);
107 			addon = place + ((board[j] * a > 2 || j == b) ? 5 : 0);
108 			if ((j == b && menstuck == 1) &&
109 			    (j != b && menstuck == 0))
110 				for (k = 1; k < diff; k++)
111 					if (k < 7 && diff - k < 7 &&
112 					    (board[i + a * k] * a >= 0 ||
113 						board[i + a * (diff - k)] >= 0))
114 						odds(k, diff - k, addon);
115 			if ((j == b || menstuck < 2) && diff < 7)
116 				odds(diff, 0, addon);
117 		}
118 		if (j == b && menstuck > 1)
119 			break;
120 	}
121 	return (count());
122 }
123