xref: /external/parameter-framework/upstream/parameter/LogarithmicParameterAdaptation.cpp

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#include "LogarithmicParameterAdaptation.h"
#include <cmath>
#include <limits>
#include <algorithm>

#define base CLinearParameterAdaptation

CLogarithmicParameterAdaptation::CLogarithmicParameterAdaptation() : base("Logarithmic")
{
    static_assert(std::numeric_limits<double>::is_iec559,
                  "Only double-precision floating points that are compliant with"
                  " IEC 559 (aka IEEE 754) are supported");
}

// Element properties
void CLogarithmicParameterAdaptation::showProperties(std::string &strResult) const
{
    base::showProperties(strResult);

    strResult += " - LogarithmBase: ";
    strResult += std::to_string(_dLogarithmBase);
    strResult += "\n";
    strResult += " - FloorValue: ";
    strResult += std::to_string(_dFloorValue);
    strResult += "\n";
}

bool CLogarithmicParameterAdaptation::fromXml(const CXmlElement &xmlElement,
                                              CXmlSerializingContext &serializingContext)
{
    if (xmlElement.getAttribute("LogarithmBase", _dLogarithmBase) &&
        (_dLogarithmBase <= 0 || _dLogarithmBase == 1)) {
        // Avoid negative and 1 values
        serializingContext.setError("LogarithmBase attribute cannot be negative or 1 on element" +
                                    xmlElement.getPath());

        return false;
    }

    xmlElement.getAttribute("FloorValue", _dFloorValue);

    // Base
    return base::fromXml(xmlElement, serializingContext);
}

int64_t CLogarithmicParameterAdaptation::fromUserValue(double value) const
{
    return std::max(base::fromUserValue(log(value) / log(_dLogarithmBase)),
                    static_cast<int64_t>(_dFloorValue));
}

double CLogarithmicParameterAdaptation::toUserValue(int64_t iValue) const
{
    return exp(base::toUserValue(iValue) * log(_dLogarithmBase));
}