source: vscpl/src/hu/varadiistvan/scpl/PseudoRandom.cc

Last change on this file was 8:7b2598d1ea55, checked in by István Váradi <ivaradi@…>, 12 years ago

Imported the I/O library for POSIX and the pseudo-random generator

File size: 2.6 KB
Line 
1// Copyright (c) 2013 by István Váradi
2
3// This file is part of VSCPL, a simple cross-platform utility library
4
5// Redistribution and use in source and binary forms, with or without
6// modification, are permitted provided that the following conditions are met:
7
8// 1. Redistributions of source code must retain the above copyright notice, this
9// list of conditions and the following disclaimer.
10// 2. Redistributions in binary form must reproduce the above copyright notice,
11// this list of conditions and the following disclaimer in the documentation
12// and/or other materials provided with the distribution.
13
14// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
15// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
16// WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
17// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
18// ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
19// (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
20// LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
21// ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
23// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24
25// The views and conclusions contained in the software and documentation are those
26// of the authors and should not be interpreted as representing official policies,
27// either expressed or implied, of the FreeBSD Project.
28
29//------------------------------------------------------------------------------
30
31#include "PseudoRandom.h"
32
33//------------------------------------------------------------------------------
34
35using hu::varadiistvan::scpl::PseudoRandom;
36
37//------------------------------------------------------------------------------
38
39void PseudoRandom::initialize(uint32_t seed)
40{
41 vector[0] = seed;
42 for(size_t i = 1; i<vectorSize-3; ++i) {
43 int32_t x = (static_cast<long long>(16807) *
44 static_cast<long long>(vector[i-1])) % 2147483647;
45 if (x<0) x += 2147483647;
46 vector[i] = x;
47 }
48 for(size_t i = vectorSize - 3; i<vectorSize; ++i) {
49 vector[i] = vector[i-31];
50 }
51
52 nextIndex = 0;
53
54 for(size_t i = vectorSize; i<numDiscarded; ++i) {
55 next();
56 }
57}
58
59//------------------------------------------------------------------------------
60
61// Local Variables:
62// mode: C++
63// c-basic-offset: 4
64// indent-tabs-mode: nil
65// End:
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