calibrationservice.cpp

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// SPDX-FileCopyrightText: 2022-2023 Paul Colby <git@colby.id.au>
// SPDX-License-Identifier: LGPL-3.0-or-later
 
/*!
 * \file
 * Defines the CalibrationService and CalibrationServicePrivate classes.
 */
 
#include <qtpokit/calibrationservice.h>
#include "calibrationservice_p.h"
 
#include <QtEndian>
 
/*!
 * \class CalibrationService
 *
 * The CalibrationService class accesses the `Calibrartion` service of Pokit devices.
 */
 
 
/*!
 * Constructs a new Pokit service with \a parent.
 */
CalibrationService::CalibrationService(QLowEnergyController * const controller, QObject * parent)
    : AbstractPokitService(new CalibrationServicePrivate(controller, this), parent)
{
 
}
 
/*!
 * \cond internal
 * Constructs a new Pokit service with \a parent, and private implementation \a d.
 */
CalibrationService::CalibrationService(
    CalibrationServicePrivate * const d, QObject * const parent)
    : AbstractPokitService(d, parent)
{
 
}
/// \endcond
 
/*!
 * Destroys this CalibrationService object.
 */
CalibrationService::~CalibrationService()
{
 
}
 
/*!
 * \copybrief AbstractPokitService::readCharacteristics
 *
 * This implementation always returns `true`, since the Calibration service provides no *readable*
 * characteristics (they're all write-only).
 */
bool CalibrationService::readCharacteristics()
{
    Q_D(CalibrationService);
    qCDebug(d->lc).noquote() << tr("Ignoring read request; the Calibration service is write-only.");
    return true;
}
 
/*!
 * Set's the Pokit device's name to \a name.
 *
 * Returns `true` if the write request was successfully queued, `false` otherwise.
 *
 * Emits deviceNameWritten() if/when the \a name has been set.
 */
bool CalibrationService::calibrateTemperature(const float ambientTemperature)
{
    static_assert(sizeof(float) == 4, "Pokit devices expect 32-bit floats");
    Q_D(const CalibrationService);
    const QLowEnergyCharacteristic characteristic =
        d->getCharacteristic(CharacteristicUuids::temperature);
    if (!characteristic.isValid()) {
        return false;
    }
 
    const QByteArray newValue = CalibrationServicePrivate::encodeTemperature(ambientTemperature);
    qCDebug(d->lc).noquote() << tr("Writing new temperature %1 (0x%2).")
        .arg(ambientTemperature).arg(QLatin1String(newValue.toHex()));
    d->service->writeCharacteristic(characteristic, newValue);
    return (d->service->error() != QLowEnergyService::ServiceError::CharacteristicWriteError);
}
 
/*!
 * \fn CalibrationService::temperatureCalibrated
 *
 * This signal is emitted when the `Temperature` characteristic has been written succesfully.
 *
 * \see calibrateTemperature
 */
 
/*!
 * \cond internal
 * \class CalibrationServicePrivate
 *
 * The CalibrationServicePrivate class provides private implementation for CalibrationService.
 */
 
/*!
 * \internal
 * Constructs a new CalibrationServicePrivate object with public implementation \a q.
 */
CalibrationServicePrivate::CalibrationServicePrivate(
    QLowEnergyController * controller, CalibrationService * const q)
    : AbstractPokitServicePrivate(CalibrationService::serviceUuid, controller, q)
{
 
}
 
/*!
 * Returns \a value in a format Pokit devices expect. Specifically, this just enocdes \a value as
 * a 32-bit float in litte-endian byte order.
 */
QByteArray CalibrationServicePrivate::encodeTemperature(const float value)
{
    static_assert(sizeof(value) == 4, "Pokit devices expect 32-bit floats");
    QByteArray bytes(sizeof(float), '\0');
    qToLittleEndian<float>(value, bytes.data());
    return bytes;
}
 
/*!
 * Implements AbstractPokitServicePrivate::characteristicWritten to parse \a newValue, then emit a
 * specialised signal, for each supported \a characteristic.
 */
void CalibrationServicePrivate::characteristicWritten(const QLowEnergyCharacteristic &characteristic,
                                                 const QByteArray &newValue)
{
    AbstractPokitServicePrivate::characteristicWritten(characteristic, newValue);
 
    Q_Q(CalibrationService);
    if (characteristic.uuid() == CalibrationService::CharacteristicUuids::temperature) {
        Q_EMIT q->temperatureCalibrated();
        return;
    }
 
    qCWarning(lc).noquote() << tr("Unknown characteristic written for Calibration service")
        << serviceUuid << characteristic.name() << characteristic.uuid();
}
 
/// \endcond