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 1.2 2003/06/17 04:25:22 dillon Exp $ 36 */ 37 38 #include "back.h" 39 40 movallow () { 41 42 int i, m, iold; 43 int r; 44 45 if (d0) 46 swap; 47 m = (D0 == D1? 4: 2); 48 for (i = 0; i < 4; i++) 49 p[i] = bar; 50 i = iold = 0; 51 while (i < m) { 52 if (*offptr == 15) 53 break; 54 h[i] = 0; 55 if (board[bar]) { 56 if (i == 1 || m == 4) 57 g[i] = bar+cturn*D1; 58 else 59 g[i] = bar+cturn*D0; 60 if (r = makmove(i)) { 61 if (d0 || m == 4) 62 break; 63 swap; 64 movback (i); 65 if (i > iold) 66 iold = i; 67 for (i = 0; i < 4; i++) 68 p[i] = bar; 69 i = 0; 70 } else 71 i++; 72 continue; 73 } 74 if ((p[i] += cturn) == home) { 75 if (i > iold) 76 iold = i; 77 if (m == 2 && i) { 78 movback(i); 79 p[i--] = bar; 80 if (p[i] != bar) 81 continue; 82 else 83 break; 84 } 85 if (d0 || m == 4) 86 break; 87 swap; 88 movback (i); 89 for (i = 0; i < 4; i++) 90 p[i] = bar; 91 i = 0; 92 continue; 93 } 94 if (i == 1 || m == 4) 95 g[i] = p[i]+cturn*D1; 96 else 97 g[i] = p[i]+cturn*D0; 98 if (g[i]*cturn > home) { 99 if (*offptr >= 0) 100 g[i] = home; 101 else 102 continue; 103 } 104 if (board[p[i]]*cturn > 0 && (r = makmove(i)) == 0) 105 i++; 106 } 107 movback (i); 108 return (iold > i? iold: i); 109 } 110