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allow.c revision 1.6 
      1 /*	$NetBSD: allow.c,v 1.6 2005/07/01 01:12:39 jmc 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 <sys/cdefs.h>
     33 #ifndef lint
     34 #if 0
     35 static char sccsid[] = "@(#)allow.c	8.1 (Berkeley) 5/31/93";
     36 #else
     37 __RCSID("$NetBSD: allow.c,v 1.6 2005/07/01 01:12:39 jmc Exp $");
     38 #endif
     39 #endif /* not lint */
     40 
     41 #include "back.h"
     42 
     43 int
     44 movallow(void)
     45 {
     46 	int     i, m, iold;
     47 	int     r;
     48 
     49 	if (d0)
     50 		swap;
     51 	m = (D0 == D1 ? 4 : 2);
     52 	for (i = 0; i < 4; i++)
     53 		p[i] = bar;
     54 	i = iold = 0;
     55 	while (i < m) {
     56 		if (*offptr == 15)
     57 			break;
     58 		h[i] = 0;
     59 		if (board[bar]) {
     60 			if (i == 1 || m == 4)
     61 				g[i] = bar + cturn * D1;
     62 			else
     63 				g[i] = bar + cturn * D0;
     64 			if ((r = makmove(i)) != 0) {
     65 				if (d0 || m == 4)
     66 					break;
     67 				swap;
     68 				movback(i);
     69 				if (i > iold)
     70 					iold = i;
     71 				for (i = 0; i < 4; i++)
     72 					p[i] = bar;
     73 				i = 0;
     74 			} else
     75 				i++;
     76 			continue;
     77 		}
     78 		if ((p[i] += cturn) == home) {
     79 			if (i > iold)
     80 				iold = i;
     81 			if (m == 2 && i) {
     82 				movback(i);
     83 				p[i--] = bar;
     84 				if (p[i] != bar)
     85 					continue;
     86 				else
     87 					break;
     88 			}
     89 			if (d0 || m == 4)
     90 				break;
     91 			swap;
     92 			movback(i);
     93 			for (i = 0; i < 4; i++)
     94 				p[i] = bar;
     95 			i = 0;
     96 			continue;
     97 		}
     98 		if (i == 1 || m == 4)
     99 			g[i] = p[i] + cturn * D1;
    100 		else
    101 			g[i] = p[i] + cturn * D0;
    102 		if (g[i] * cturn > home) {
    103 			if (*offptr >= 0)
    104 				g[i] = home;
    105 			else
    106 				continue;
    107 		}
    108 		if (board[p[i]] * cturn > 0 && (r = makmove(i)) == 0)
    109 			i++;
    110 	}
    111 	movback(i);
    112 	return (iold > i ? iold : i);
    113 }
    114