1 /* @(#)allow.c 8.1 (Berkeley) 5/31/93 */
2 /* $NetBSD: allow.c,v 1.8 2012/10/13 19:19:38 dholland Exp $ */
3
4 /*
5 * Copyright (c) 1980, 1993
6 * The Regents of the University of California. All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. Neither the name of the University nor the names of its contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 */
32
33 #include "back.h"
34
35 int
movallow(struct move * mm)36 movallow(struct move *mm)
37 {
38 int i, m, iold;
39 int r;
40
41 if (mm->d0)
42 mswap(mm);
43 m = (mm->D0 == mm->D1 ? 4 : 2);
44 for (i = 0; i < 4; i++)
45 mm->p[i] = bar;
46 i = iold = 0;
47 while (i < m) {
48 if (*offptr == 15)
49 break;
50 mm->h[i] = 0;
51 if (board[bar]) {
52 if (i == 1 || m == 4)
53 mm->g[i] = bar + cturn * mm->D1;
54 else
55 mm->g[i] = bar + cturn * mm->D0;
56 if ((r = makmove(mm, i)) != 0) {
57 if (mm->d0 || m == 4)
58 break;
59 mswap(mm);
60 movback(mm, i);
61 if (i > iold)
62 iold = i;
63 for (i = 0; i < 4; i++)
64 mm->p[i] = bar;
65 i = 0;
66 } else
67 i++;
68 continue;
69 }
70 if ((mm->p[i] += cturn) == home) {
71 if (i > iold)
72 iold = i;
73 if (m == 2 && i) {
74 movback(mm, i);
75 mm->p[i--] = bar;
76 if (mm->p[i] != bar)
77 continue;
78 else
79 break;
80 }
81 if (mm->d0 || m == 4)
82 break;
83 mswap(mm);
84 movback(mm, i);
85 for (i = 0; i < 4; i++)
86 mm->p[i] = bar;
87 i = 0;
88 continue;
89 }
90 if (i == 1 || m == 4)
91 mm->g[i] = mm->p[i] + cturn * mm->D1;
92 else
93 mm->g[i] = mm->p[i] + cturn * mm->D0;
94 if (mm->g[i] * cturn > home) {
95 if (*offptr >= 0)
96 mm->g[i] = home;
97 else
98 continue;
99 }
100 if (board[mm->p[i]] * cturn > 0 && (r = makmove(mm, i)) == 0)
101 i++;
102 }
103 movback(mm, i);
104 return (iold > i ? iold : i);
105 }
106