1 /* $NetBSD: random.h,v 1.5 2021/12/05 09:22:45 rillig 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 * 19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32 /* 33 * Randomizer; returns a random sequence of values from [0..fx) returning each 34 * value exactly once. After fx calls it returns fx. 35 */ 36 37 #ifndef _H_RANDOM 38 #define _H_RANDOM 39 40 #include <stdlib.h> 41 42 class RANDOM { 43 public: 44 // Constructor and destructor 45 RANDOM(size_t fx); 46 ~RANDOM(); 47 48 size_t operator () (void); // Next random 49 void clear(void); // Reset 50 51 private: 52 isset(size_t z)53 int isset(size_t z) { 54 return (_bm[z >> 3] & (1 << (z & 7))) != 0; 55 } 56 set(size_t z)57 void set(size_t z) { 58 _bm[z >> 3] |= (1 << (z & 7)); 59 } 60 61 char* _bm; // Bitmap indicating the numbers used 62 size_t _nv; // Number of values returned so far 63 size_t _bs; // Maximum value 64 }; 65 66 #endif 67