1 /* $NetBSD: allow.c,v 1.9 2024/08/22 20:46:40 rillig 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 1.9 2024/08/22 20:46:40 rillig Exp $"); 38 #endif 39 #endif /* not lint */ 40 41 #include "back.h" 42 43 int 44 movallow(struct move *mm) 45 { 46 int i, m, iold; 47 48 if (mm->d0) 49 mswap(mm); 50 m = (mm->D0 == mm->D1 ? 4 : 2); 51 for (i = 0; i < 4; i++) 52 mm->p[i] = bar; 53 i = iold = 0; 54 while (i < m) { 55 if (*offptr == 15) 56 break; 57 mm->h[i] = 0; 58 if (board[bar]) { 59 if (i == 1 || m == 4) 60 mm->g[i] = bar + cturn * mm->D1; 61 else 62 mm->g[i] = bar + cturn * mm->D0; 63 if (makmove(mm, i) != 0) { 64 if (mm->d0 || m == 4) 65 break; 66 mswap(mm); 67 movback(mm, i); 68 if (i > iold) 69 iold = i; 70 for (i = 0; i < 4; i++) 71 mm->p[i] = bar; 72 i = 0; 73 } else 74 i++; 75 continue; 76 } 77 if ((mm->p[i] += cturn) == home) { 78 if (i > iold) 79 iold = i; 80 if (m == 2 && i) { 81 movback(mm, i); 82 mm->p[i--] = bar; 83 if (mm->p[i] != bar) 84 continue; 85 else 86 break; 87 } 88 if (mm->d0 || m == 4) 89 break; 90 mswap(mm); 91 movback(mm, i); 92 for (i = 0; i < 4; i++) 93 mm->p[i] = bar; 94 i = 0; 95 continue; 96 } 97 if (i == 1 || m == 4) 98 mm->g[i] = mm->p[i] + cturn * mm->D1; 99 else 100 mm->g[i] = mm->p[i] + cturn * mm->D0; 101 if (mm->g[i] * cturn > home) { 102 if (*offptr >= 0) 103 mm->g[i] = home; 104 else 105 continue; 106 } 107 if (board[mm->p[i]] * cturn > 0 && makmove(mm, i) == 0) 108 i++; 109 } 110 movback(mm, i); 111 return (iold > i ? iold : i); 112 } 113