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