KisPerStrokeRandomSource.cpp

Go to the documentation of this file.

/*
 *  SPDX-FileCopyrightText: 2017 Dmitry Kazakov <dimula73@gmail.com>
 *
 *  SPDX-License-Identifier: GPL-2.0-or-later
 */
 
#include "KisPerStrokeRandomSource.h"
 
#include <QHash>
#include <QMutex>
#include <QMutexLocker>
#include <QRandomGenerator>
 
#include <boost/random/normal_distribution.hpp>
#include <boost/random/taus88.hpp>
#include <boost/random/uniform_smallint.hpp>
 
struct KisPerStrokeRandomSource::Private
{
    Private(int _seed)
        : seed(_seed)
    {
        boost::taus88 tempGenerator(seed);
        generatorMax = tempGenerator.max();
    }
 
    Private(const Private &rhs)
        : seed(rhs.seed),
          generatorMax(rhs.generatorMax),
          valuesCache(rhs.valuesCache)
    {
    }
 
    qint64 fetchInt(const QString &key);
 
    int seed = 0;
    qint64 generatorMax = 0;
    QHash<QString, qint64> valuesCache;
    QMutex mutex;
};
 
KisPerStrokeRandomSource::KisPerStrokeRandomSource()
    : m_d(new Private(QRandomGenerator::global()->generate()))
{
 
}
 
KisPerStrokeRandomSource::KisPerStrokeRandomSource(const KisPerStrokeRandomSource &rhs)
    : KisShared(),
      m_d(new Private(*rhs.m_d))
{
}
 
KisPerStrokeRandomSource::~KisPerStrokeRandomSource()
{
}
 
 
qint64 KisPerStrokeRandomSource::Private::fetchInt(const QString &key)
{
    QMutexLocker l(&mutex);
 
    auto it = valuesCache.find(key);
    if (it != valuesCache.end()) {
        return it.value();
    }
 
    boost::taus88 oneTimeGenerator(seed + qHash(key));
    const qint64 newValue = oneTimeGenerator();
 
    valuesCache.insert(key, newValue);
 
    return newValue;
}
 
int KisPerStrokeRandomSource::generate(const QString &key, int min, int max) const
{
    return min + m_d->fetchInt(key) % (max - min);
}
 
qreal KisPerStrokeRandomSource::generateNormalized(const QString &key) const
{
    return qreal(m_d->fetchInt(key)) / m_d->generatorMax;
}