1 /*-
2  * Copyright (c) 1980, 1993
3  *	The Regents of the University of California.  All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. Neither the name of the University nor the names of its contributors
14  *    may be used to endorse or promote products derived from this software
15  *    without specific prior written permission.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  *
29  * @(#)one.c	8.1 (Berkeley) 5/31/93
30  * $FreeBSD: src/games/backgammon/common_source/one.c,v 1.5 1999/11/30 03:48:27 billf Exp $
31  * $DragonFly: src/games/backgammon/common_source/one.c,v 1.3 2006/08/08 16:36:11 pavalos Exp $
32  */
33 
34 #include "back.h"
35 
36 static int	checkd(int);
37 static int	last(void);
38 
39 int
40 makmove(int i)
41 {
42 	int n, d;
43 	int max;
44 
45 	d = d0;
46 	n = abs(g[i] - p[i]);
47 	max = (*offptr < 0 ? 7 : last());
48 	if (board[p[i]] * cturn <= 0)
49 		return (checkd(d) + 2);
50 	if (g[i] != home && board[g[i]] * cturn < -1)
51 		return (checkd(d) + 3);
52 	if (i || D0 == D1) {
53 		if (n == max ? D1 < n : D1 != n)
54 			return (checkd(d) + 1);
55 	} else {
56 		if (n == max ? D0 < n && D1 < n : D0 != n && D1 != n)
57 			return (checkd(d) + 1);
58 		if (n == max ? D0 < n : D0 != n) {
59 			if (d0)
60 				return (checkd(d) + 1);
61 			swap;
62 		}
63 	}
64 	if (g[i] == home && *offptr < 0)
65 		return (checkd(d) + 4);
66 	h[i] = 0;
67 	board[p[i]] -= cturn;
68 	if (g[i] != home) {
69 		if (board[g[i]] == -cturn) {
70 			board[home] -= cturn;
71 			board[g[i]] = 0;
72 			h[i] = 1;
73 			if (abs(bar - g[i]) < 7) {
74 				(*inopp)--;
75 				if (*offopp >= 0)
76 					*offopp -= 15;
77 			}
78 		}
79 		board[g[i]] += cturn;
80 		if (abs(home - g[i]) < 7 && abs(home - p[i]) > 6) {
81 			(*inptr)++;
82 			if (*inptr + *offptr == 0)
83 				*offptr += 15;
84 		}
85 	} else {
86 		(*offptr)++;
87 		(*inptr)--;
88 	}
89 	return (0);
90 }
91 
92 void
93 moverr(int i)
94 {
95 	int j;
96 
97 	if (tflag)
98 		curmove(20, 0);
99 	else
100 		writec('\n');
101 	writel("Error:  ");
102 	for (j = 0; j <= i; j++) {
103 		wrint(p[j]);
104 		writec('-');
105 		wrint(g[j]);
106 		if (j < i)
107 			writec(',');
108 	}
109 	writel("... ");
110 	movback(i);
111 }
112 
113 static int
114 checkd(int d)
115 {
116 	if (d0 != d)
117 		swap;
118 	return (0);
119 }
120 
121 static int
122 last(void)
123 {
124 	int i;
125 
126 	for (i = home - 6 * cturn; i != home; i += cturn)
127 		if (board[i] * cturn > 0)
128 			return (abs(home - i));
129 	return (-1);
130 }
131 
132 void
133 movback(int i)
134 {
135 	int j;
136 
137 	for (j = i - 1; j >= 0; j--)
138 		backone(j);
139 }
140 
141 void
142 backone(int i)
143 {
144 	board[p[i]] += cturn;
145 	if (g[i] != home) {
146 		board[g[i]] -= cturn;
147 		if (abs(g[i] - home) < 7 && abs(p[i] - home) > 6) {
148 			(*inptr)--;
149 			if (*inptr + *offptr < 15 && *offptr >= 0)
150 				*offptr -= 15;
151 		}
152 	} else {
153 		(*offptr)--;
154 		(*inptr)++;
155 	}
156 	if (h[i]) {
157 		board[home] += cturn;
158 		board[g[i]] = -cturn;
159 		if (abs(bar - g[i]) < 7) {
160 			(*inopp)++;
161 			if (*inopp + *offopp == 0)
162 				*offopp += 15;
163 		}
164 	}
165 }
166