1 /* 2 * Copyright (c) 1980, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * @(#)allow.c 8.1 (Berkeley) 5/31/93 34 * $FreeBSD: src/games/backgammon/common_source/allow.c,v 1.4 1999/11/30 03:48:24 billf Exp $ 35 * $DragonFly: src/games/backgammon/common_source/allow.c,v 1.3 2006/08/08 16:36:11 pavalos Exp $ 36 */ 37 38 #include "back.h" 39 40 int 41 movallow(void) 42 { 43 44 int i, m, iold; 45 int r; 46 47 if (d0) 48 swap; 49 m = (D0 == D1? 4: 2); 50 for (i = 0; i < 4; i++) 51 p[i] = bar; 52 i = iold = 0; 53 while (i < m) { 54 if (*offptr == 15) 55 break; 56 h[i] = 0; 57 if (board[bar]) { 58 if (i == 1 || m == 4) 59 g[i] = bar+cturn*D1; 60 else 61 g[i] = bar+cturn*D0; 62 if ((r = makmove(i)) != 0) { 63 if (d0 || m == 4) 64 break; 65 swap; 66 movback (i); 67 if (i > iold) 68 iold = i; 69 for (i = 0; i < 4; i++) 70 p[i] = bar; 71 i = 0; 72 } else 73 i++; 74 continue; 75 } 76 if ((p[i] += cturn) == home) { 77 if (i > iold) 78 iold = i; 79 if (m == 2 && i) { 80 movback(i); 81 p[i--] = bar; 82 if (p[i] != bar) 83 continue; 84 else 85 break; 86 } 87 if (d0 || m == 4) 88 break; 89 swap; 90 movback (i); 91 for (i = 0; i < 4; i++) 92 p[i] = bar; 93 i = 0; 94 continue; 95 } 96 if (i == 1 || m == 4) 97 g[i] = p[i]+cturn*D1; 98 else 99 g[i] = p[i]+cturn*D0; 100 if (g[i]*cturn > home) { 101 if (*offptr >= 0) 102 g[i] = home; 103 else 104 continue; 105 } 106 if (board[p[i]]*cturn > 0 && (r = makmove(i)) == 0) 107 i++; 108 } 109 movback (i); 110 return (iold > i? iold: i); 111 } 112