ScalarSubscriber.h

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/*****************************************************************************
 *
 * Copyright (C) 2009-2022  Florian Pose <fp@igh.de>
 *
 * This file is part of the QtPdCom library.
 *
 * The QtPdCom library is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or (at your
 * option) any later version.
 *
 * The QtPdCom library is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
 * License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with the QtPdCom Library. If not, see <http://www.gnu.org/licenses/>.
 *
 ****************************************************************************/
 
#ifndef QTPDCOM_SCALARSUBSCRIBER_H
#define QTPDCOM_SCALARSUBSCRIBER_H
 
#include "Transmission.h"
#include "Export.h"
 
#include <pdcom5/Variable.h>
#include <pdcom5/Subscription.h>
 
#include <QDebug> // qWarning()
 
namespace QtPdCom {
 
/****************************************************************************/
 
class QTPDCOM_PUBLIC ScalarSubscriber
{
    public:
        ScalarSubscriber();
        virtual ~ScalarSubscriber();
 
        void setVariable(
                PdCom::Variable pv, 
                const PdCom::Selector &selector = {}, 
                const Transmission & = event_mode, 
                double scale = 1.0, 
                double offset = 0.0, 
                double tau = 0.0 
                );
 
        void setVariable(
                PdCom::Process *process, 
                const QString &path, 
                const PdCom::Selector &selector = {}, 
                const Transmission & = event_mode, 
                double scale = 1.0, 
                double offset = 0.0, 
                double tau = 0.0 
                );
        void clearVariable();
        bool hasVariable() const; 
        virtual void newValues(std::chrono::nanoseconds) = 0;
        virtual void stateChange(PdCom::Subscription::State);
 
        template <class T> void writeValue(T);
 
        double getFilterConstant() const;
 
        PdCom::Variable getVariable() const;
        const void *getData() const;
 
        Q_INVOKABLE bool poll();
 
    protected:
        double scale;
        double offset;
 
        const PdCom::Selector &getSelector() const;
 
    private:
        struct Q_DECL_HIDDEN Impl;
        std::unique_ptr<Impl> impl;
 
        ScalarSubscriber(const ScalarSubscriber &); // not to be used
};
 
/****************************************************************************/
 
template <class T>
void ScalarSubscriber::writeValue(T value)
{
    if (not hasVariable()) {
        qWarning() << "ScalarSubscriber::writeValue(): Not subscribed!";
        return;
    }
 
    if (scale == 0.0) {
        qWarning() << "Avoiding division by zero scale.";
        return;
    }
 
    getVariable().setValue((value - offset) / scale, getSelector());
}
 
/****************************************************************************/
 
} // namespace
 
#endif