ScalarVariable.h

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/*****************************************************************************
 *
 * Copyright (C) 2009-2025  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_SCALARVARIABLE_H
#define QTPDCOM_SCALARVARIABLE_H
 
#include "ScalarSubscriber.h"
#include "Export.h"
 
#include <QObject>
 
namespace QtPdCom {
 
/****************************************************************************/

class QTPDCOM_PUBLIC AbstractScalarVariable:
    public QObject,
    public ScalarSubscriber
{
        Q_OBJECT
 
    public:
        using QObject::QObject;
 
        struct Exception
        {
                Exception(const QString &msg):
                    msg(msg)
                {}
                QString msg; 
        };
 
        template <typename T>
        typename std::enable_if<std::is_arithmetic<T>::value, void>::type
        copyData(T &dest) const
        {
            PdCom::details::copyData(
                    &dest,
                    PdCom::details::TypeInfoTraits<T>::type_info.type,
                    getData(),
                    getVariable().getTypeInfo().type,
                    1);
        }
 
    signals:
        void valueChanged(); 
};
 
/****************************************************************************/

template <class T> class ScalarVariable: public AbstractScalarVariable
{
    public:
        ScalarVariable(QObject *parent = nullptr);
        virtual ~ScalarVariable();
 
        void clearData();
        bool hasData() const;
 
        T getValue() const;
        std::chrono::nanoseconds getMTime() const;
        void inc();
 
    private:
        T value; 
        std::chrono::nanoseconds mTime;
        bool dataPresent; 
 
        // pure-virtual from ScalarSubscriber
        void newValues(std::chrono::nanoseconds) override;
};
 
/****************************************************************************/
 
typedef ScalarVariable<bool> BoolVariable;
typedef ScalarVariable<int> IntVariable;
typedef ScalarVariable<double> DoubleVariable;
 
/****************************************************************************/

template <class T> ScalarVariable<T>::ScalarVariable(QObject *parent):
    AbstractScalarVariable(parent),
    value((T) 0),
    dataPresent(false)
{}
 
/****************************************************************************/

template <class T> ScalarVariable<T>::~ScalarVariable()
{}
 
/****************************************************************************/
 
template <class T> void ScalarVariable<T>::clearData()
{
    value = ((T) 0);
    dataPresent = false;
    emit valueChanged();
}
 
/****************************************************************************/

template <class T> inline bool ScalarVariable<T>::hasData() const
{
    return dataPresent;
}
 
/****************************************************************************/

template <class T> inline T ScalarVariable<T>::getValue() const
{
    return value;
}
 
/****************************************************************************/

template <class T>
inline std::chrono::nanoseconds ScalarVariable<T>::getMTime() const
{
    return mTime;
}
 
/****************************************************************************/

template <class T> void ScalarVariable<T>::inc()
{
    writeValue(value + 1);
}
 
/****************************************************************************/

template <class T>
void ScalarVariable<T>::newValues(std::chrono::nanoseconds ts)
{
    T newValue;
 
    copyData(newValue);
    newValue = newValue * scale + offset;
    mTime = std::chrono::nanoseconds(ts);
 
    if (newValue != value || !dataPresent) {
        value = newValue;
        dataPresent = true;
        emit valueChanged();
    }
}
 
/****************************************************************************/
 
}  // namespace QtPdCom
 
#endif