xref: /netbsd-src/games/dab/random.h (revision ce666bb8ce77792a3948ca697c2fdad578a542a7)
1 /*	$NetBSD: random.h,v 1.2 2003/12/28 17:49:10 thorpej 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 
49 class 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