1 /* $OpenBSD: allow.c,v 1.6 2015/11/30 08:19:25 tb 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. Neither the name of the University nor the names of its contributors
16 * may be used to endorse or promote products derived from this software
17 * without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32 #include "back.h"
33
34 int
movallow(void)35 movallow(void)
36 {
37 int i, m, iold, r;
38
39 if (d0)
40 swap;
41 m = (D0 == D1 ? 4 : 2);
42 for (i = 0; i < 4; i++)
43 p[i] = bar;
44 i = iold = 0;
45 while (i < m) {
46 if (*offptr == 15)
47 break;
48 h[i] = 0;
49 if (board[bar]) {
50 if (i == 1 || m == 4)
51 g[i] = bar + cturn * D1;
52 else
53 g[i] = bar + cturn * D0;
54 if ((r = makmove(i))) {
55 if (d0 || m == 4)
56 break;
57 swap;
58 movback(i);
59 if (i > iold)
60 iold = i;
61 for (i = 0; i < 4; i++)
62 p[i] = bar;
63 i = 0;
64 } else
65 i++;
66 continue;
67 }
68 if ((p[i] += cturn) == home) {
69 if (i > iold)
70 iold = i;
71 if (m == 2 && i) {
72 movback(i);
73 p[i--] = bar;
74 if (p[i] != bar)
75 continue;
76 else
77 break;
78 }
79 if (d0 || m == 4)
80 break;
81 swap;
82 movback(i);
83 for (i = 0; i < 4; i++)
84 p[i] = bar;
85 i = 0;
86 continue;
87 }
88 if (i == 1 || m == 4)
89 g[i] = p[i] + cturn * D1;
90 else
91 g[i] = p[i] + cturn * D0;
92 if (g[i] * cturn > home) {
93 if (*offptr >= 0)
94 g[i] = home;
95 else
96 continue;
97 }
98 if (board[p[i]] * cturn > 0 && (r = makmove(i)) == 0)
99 i++;
100 }
101 movback(i);
102 return (iold > i ? iold : i);
103 }
104