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allow.c revision 1.7 
      1 /*	$NetBSD: allow.c,v 1.7 2012/10/13 18:44:14 dholland 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 1.7 2012/10/13 18:44:14 dholland 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 	struct move *mm = &gm;
     49 
     50 	if (mm->d0)
     51 		mswap(mm);
     52 	m = (mm->D0 == mm->D1 ? 4 : 2);
     53 	for (i = 0; i < 4; i++)
     54 		mm->p[i] = bar;
     55 	i = iold = 0;
     56 	while (i < m) {
     57 		if (*offptr == 15)
     58 			break;
     59 		mm->h[i] = 0;
     60 		if (board[bar]) {
     61 			if (i == 1 || m == 4)
     62 				mm->g[i] = bar + cturn * mm->D1;
     63 			else
     64 				mm->g[i] = bar + cturn * mm->D0;
     65 			if ((r = makmove(i)) != 0) {
     66 				if (mm->d0 || m == 4)
     67 					break;
     68 				mswap(mm);
     69 				movback(i);
     70 				if (i > iold)
     71 					iold = i;
     72 				for (i = 0; i < 4; i++)
     73 					mm->p[i] = bar;
     74 				i = 0;
     75 			} else
     76 				i++;
     77 			continue;
     78 		}
     79 		if ((mm->p[i] += cturn) == home) {
     80 			if (i > iold)
     81 				iold = i;
     82 			if (m == 2 && i) {
     83 				movback(i);
     84 				mm->p[i--] = bar;
     85 				if (mm->p[i] != bar)
     86 					continue;
     87 				else
     88 					break;
     89 			}
     90 			if (mm->d0 || m == 4)
     91 				break;
     92 			mswap(mm);
     93 			movback(i);
     94 			for (i = 0; i < 4; i++)
     95 				mm->p[i] = bar;
     96 			i = 0;
     97 			continue;
     98 		}
     99 		if (i == 1 || m == 4)
    100 			mm->g[i] = mm->p[i] + cturn * mm->D1;
    101 		else
    102 			mm->g[i] = mm->p[i] + cturn * mm->D0;
    103 		if (mm->g[i] * cturn > home) {
    104 			if (*offptr >= 0)
    105 				mm->g[i] = home;
    106 			else
    107 				continue;
    108 		}
    109 		if (board[mm->p[i]] * cturn > 0 && (r = makmove(i)) == 0)
    110 			i++;
    111 	}
    112 	movback(i);
    113 	return (iold > i ? iold : i);
    114 }
    115