78 lines
2.1 KiB
C++
78 lines
2.1 KiB
C++
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#ifndef CONFIDENT_QUANTITY_HPP_B2XVJERI
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#define CONFIDENT_QUANTITY_HPP_B2XVJERI
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#include <limits>
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namespace vanetza
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{
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/**
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* ConfidentQuantity combines a boost::quantity value with a confidence level.
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*
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* Usually, a confidence level of 95% is used in ITS specifications.
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* If no confidence level is explicitly given a worst case value is used, i.e.
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* the maximum value representable by the underlying type or infinity.
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*/
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template<typename T>
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class ConfidentQuantity
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{
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public:
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constexpr T worst_confidence() const
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{
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using value_type = typename T::value_type;
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return T::from_value(std::numeric_limits<value_type>::has_infinity ?
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std::numeric_limits<value_type>::infinity() :
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std::numeric_limits<value_type>::max());
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}
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constexpr T default_value() const
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{
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using value_type = typename T::value_type;
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return T::from_value(std::numeric_limits<value_type>::has_quiet_NaN ?
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std::numeric_limits<value_type>::quiet_NaN() : value_type());
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}
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constexpr bool is_nan(const T& t) const
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{
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return t.value() != t.value();
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}
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ConfidentQuantity() :
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m_value(default_value()), m_confidence(worst_confidence()) {}
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ConfidentQuantity(const T& value) :
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m_value(value), m_confidence(worst_confidence()) {}
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ConfidentQuantity(const T& value, const T& confidence) :
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m_value(value), m_confidence(!is_nan(confidence) ? confidence : worst_confidence()) {}
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ConfidentQuantity(const ConfidentQuantity&) = default;
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ConfidentQuantity& operator=(const ConfidentQuantity&) = default;
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ConfidentQuantity(ConfidentQuantity&&) = default;
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ConfidentQuantity& operator=(ConfidentQuantity&&) = default;
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void assign(const T& value, const T& confidence)
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{
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m_value = value;
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m_confidence = !is_nan(confidence) ? confidence : worst_confidence();
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}
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const T& value() const
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{
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return m_value;
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}
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const T& confidence() const
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{
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return m_confidence;
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}
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private:
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T m_value;
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T m_confidence;
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};
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} // namespace vanetza
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#endif /* CONFIDENT_QUANTITY_HPP_B2XVJERI */
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