67 lines
2.2 KiB
C++
67 lines
2.2 KiB
C++
/* $NetBSD: random.h,v 1.5 2021/12/05 09:22:45 rillig Exp $ */
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/*-
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* Copyright (c) 2003 The NetBSD Foundation, Inc.
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* All rights reserved.
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*
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* This code is derived from software contributed to The NetBSD Foundation
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* by Christos Zoulas.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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/*
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* Randomizer; returns a random sequence of values from [0..fx) returning each
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* value exactly once. After fx calls it returns fx.
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*/
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#ifndef _H_RANDOM
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#define _H_RANDOM
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#include <stdlib.h>
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class RANDOM {
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public:
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// Constructor and destructor
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RANDOM(size_t fx);
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~RANDOM();
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size_t operator () (void); // Next random
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void clear(void); // Reset
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private:
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int isset(size_t z) {
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return (_bm[z >> 3] & (1 << (z & 7))) != 0;
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}
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void set(size_t z) {
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_bm[z >> 3] |= (1 << (z & 7));
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}
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char* _bm; // Bitmap indicating the numbers used
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size_t _nv; // Number of values returned so far
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size_t _bs; // Maximum value
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};
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#endif
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