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random.cc revision 1.4 
      1 /*	$NetBSD: random.cc,v 1.4 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 for the dots program
     34  */
     35 
     36 #include "defs.h"
     37 RCSID("$NetBSD: random.cc,v 1.4 2021/12/05 09:22:45 rillig Exp $")
     38 
     39 #include <time.h>
     40 #include <string.h>
     41 #include "random.h"
     42 
     43 RANDOM::RANDOM(size_t ns) :
     44     _bs(ns)
     45 {
     46     _bm = new char[(_bs >> 3) + 1];
     47     clear();
     48 }
     49 
     50 RANDOM::~RANDOM()
     51 {
     52     delete[] _bm;
     53 }
     54 
     55 // Reinitialize
     56 void RANDOM::clear(void)
     57 {
     58     _nv = 0;
     59     ::srand48(::time(NULL));
     60     (void) ::memset(_bm, 0, (_bs >> 3) + 1);
     61 }
     62 
     63 // Return the next random value
     64 size_t RANDOM::operator() (void)
     65 {
     66     // No more values
     67     if (_nv == _bs)
     68 	return _bs;
     69 
     70     for (;;) {
     71 	size_t r = ::lrand48();
     72 	size_t z = r % _bs;
     73         if (!isset(z)) {
     74 	    set(z);
     75 	    _nv++;
     76 	    return z;
     77 	}
     78     }
     79 }
     80