random.h revision 1.1
1/* $Header: /usr/local/opengrok/home/cvs-mirror/mirrors/netbsd/src/games/dab/random.h,v 1.1 2003/12/26 17:57:04 christos Exp $ */ 2 3/*- 4 * Copyright (c) 2003 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Christos Zoulas. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the NetBSD 21 * Foundation, Inc. and its contributors. 22 * 4. Neither the name of The NetBSD Foundation nor the names of its 23 * contributors may be used to endorse or promote products derived 24 * from this software without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 27 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 28 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 29 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 30 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 31 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 32 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 33 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 34 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 35 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 36 * POSSIBILITY OF SUCH DAMAGE. 37 */ 38 39/* 40 * random.h: Randomizer; returns a random sequence of values from [0..fx) 41 * returning each value exactly once. After fx calls it returns fx. 42 */ 43 44#ifndef _H_RANDOM 45#define _H_RANDOM 46 47#include <stdlib.h> 48 49class RANDOM { 50 public: 51 // Constructor and destructor 52 RANDOM(size_t fx); 53 ~RANDOM(); 54 55 size_t operator () (void); // Next random 56 void clear(void); // Reset 57 58 private: 59 60 int isset(size_t z) { 61 return (_bm[z >> 3] & (1 << (z & 7))) != 0; 62 } 63 64 void set(size_t z) { 65 _bm[z >> 3] |= (1 << (z & 7)); 66 } 67 68 char* _bm; // Bitmap indicating the numbers used 69 size_t _nv; // Number of values returned so far 70 size_t _bs; // Maximum value 71}; 72 73#endif 74