sensor_reader.h

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/**
 * @file    sensor_reader.h
 * @brief Declaration for SensorReader, the class used to acquire readings from a sensor.
 *
 * @date September 12, 2019
 * @author Matthew Kennedy, (c) 2019
 */
 
#pragma once
 
#include "sensor.h"
 
/**
 * @brief Provides an interface for reading sensors.
 *
 * Example usage:
 *
 * // Create a sensor reader for type MySensor, and fallback value 10.0
 * SensorReader<SensorType::MySensor> mySensorReader(10.0f);
 *
 * <later>
 *
 * // Returns the sensor value if valid, or 10.0 if invalid.
 * float currentSensorValue = mySensorReader.getOrDefault();
 * alternatively, because we have implicit conversion:
 * float currentSensorValue = mySensorReader;
 *
 * Simply calling the get() method returns the full SensorResult, should
 * more complex logic be required in case of an invalid sensor reading.
 */
template <SensorType TSensorType>
class SensorReader final {
public:
    using sensorValueType = float;
 
    explicit SensorReader(sensorValueType defaultValue)
        : m_defaultValue(defaultValue) {}
 
    SensorResult get() const {
        return Sensor::get(TSensorType);
    }
 
    // Get the sensor's reading, or a default value.
    // Inteded for applications where a default may be used silently,
    // while elsewhere in the world the failed sensor is otherwise handled.
    sensorValueType getOrDefault() const {
        auto result = get();
 
        if (result.Valid) {
            return (sensorValueType)result.Value;
        } else {
            return m_defaultValue;
        }
    }
 
    // Implicit conversion operator
    operator sensorValueType() const {
        return getOrDefault();
    }
 
private:
    const sensorValueType m_defaultValue;
};