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 * @(#)odds.c 8.1 (Berkeley) 5/31/93 30 * $FreeBSD: src/games/backgammon/common_source/odds.c,v 1.5 1999/11/30 03:48:26 billf Exp $ 31 * $DragonFly: src/games/backgammon/common_source/odds.c,v 1.3 2006/08/08 16:36:11 pavalos Exp $ 32 */ 33 34 #include "back.h" 35 36 void 37 odds(int r1, int r2, int val) 38 { 39 int i, j; 40 41 if (r1 == 0) { 42 for (i = 0; i < 6; i++) 43 for (j = 0; j < 6; j++) 44 table[i][j] = 0; 45 return; 46 } else { 47 r1--; 48 if (r2-- == 0) { 49 for (i = 0; i < 6; i++) { 50 table[i][r1] += val; 51 table[r1][i] += val; 52 } 53 } else { 54 table[r2][r1] += val; 55 table[r1][r2] += val; 56 } 57 } 58 } 59 60 int 61 count(void) 62 { 63 int i, j, total; 64 65 total = 0; 66 for (i = 0; i < 6; i++) 67 for (j = 0; j < 6; j++) 68 total += table[i][j]; 69 return (total); 70 } 71 72 int 73 canhit(int i, int c) 74 { 75 int j, k, b; 76 int a, diff, place, addon, menstuck; 77 78 if (c == 0) 79 odds(0, 0, 0); 80 if (board[i] > 0) { 81 a = -1; 82 b = 25; 83 } else { 84 a = 1; 85 b = 0; 86 } 87 place = abs(25 - b - i); 88 menstuck = abs(board[b]); 89 for (j = b; j != i; j += a) { 90 if (board[j] * a > 0) { 91 diff = abs(j - i); 92 addon = place + ((board[j] * a > 2 || j == b) ? 5 : 0); 93 if ((j == b && menstuck == 1) && 94 (j != b && menstuck == 0)) 95 for (k = 1; k < diff; k++) 96 if (k < 7 && diff - k < 7 && 97 (board[i + a * k] * a >= 0 || 98 board[i + a * (diff - k)] >= 0)) 99 odds(k, diff - k, addon); 100 if ((j == b || menstuck < 2) && diff < 7) 101 odds(diff, 0, addon); 102 } 103 if (j == b && menstuck > 1) 104 break; 105 } 106 return (count()); 107 } 108