97 lines
2.5 KiB
C++
97 lines
2.5 KiB
C++
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#ifndef UNIT_INTERVAL_HPP_BG1EK7QX
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#define UNIT_INTERVAL_HPP_BG1EK7QX
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#include <boost/operators.hpp>
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#include <iterator>
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#include <type_traits>
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namespace vanetza
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{
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/**
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* UnitInterval represents a number within the unit interval [0.0, 1.0]
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*
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* UnitInterval is not an interval on its own but limits all numbers to this interval.
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* Mantissa (positive fractional part of a real number) behaves differently, thus:
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* - Mantissa(42.1234) = 0.1234
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* - UnitInterval(42.1234) = 1.0
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* UnitInterval is also related to "(proper) decimal fraction" but latter does not include 1.0.
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*/
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class UnitInterval :
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boost::arithmetic<UnitInterval>,
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boost::arithmetic<UnitInterval, double>,
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boost::totally_ordered<UnitInterval>
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{
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public:
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constexpr UnitInterval() : UnitInterval(0.0) {}
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constexpr explicit UnitInterval(double v) : m_value(clamp(v)) {}
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UnitInterval(const UnitInterval&) = default;
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UnitInterval& operator=(const UnitInterval&) = default;
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// arithmetic
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UnitInterval& operator+=(const UnitInterval&);
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UnitInterval& operator-=(const UnitInterval&);
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UnitInterval& operator*=(const UnitInterval&);
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UnitInterval& operator/=(const UnitInterval&);
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UnitInterval& operator+=(double);
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UnitInterval& operator-=(double);
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UnitInterval& operator*=(double);
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UnitInterval& operator/=(double);
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// partially ordered
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bool operator<(const UnitInterval& other) const;
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bool operator==(const UnitInterval& other) const;
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double value() const { return m_value; }
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UnitInterval complement() const;
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private:
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constexpr static double clamp(double v)
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{
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return (v > 1.0 ? 1.0 : (v < 0.0 ? 0.0 : v));
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}
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UnitInterval& clamp();
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double m_value;
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};
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/**
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* Calculate mean value of two unit intervals
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* \param lhs
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* \param rhs
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* \return mean unit interval
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*/
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UnitInterval mean(UnitInterval lhs, UnitInterval rhs);
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/**
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* Calculate mean of a range of unit intervals
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* \param begin of range
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* \params end of range
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* \reutrn mean unit interval
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*/
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template<
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typename Iterator,
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typename std::enable_if<
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std::is_convertible<typename std::iterator_traits<Iterator>::value_type, UnitInterval>::value,
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int>::type = 0
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>
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UnitInterval mean(Iterator begin, Iterator end)
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{
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unsigned count = 0;
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double accu = 0.0;
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for (Iterator it = begin; it != end; ++it)
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{
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accu += it->value();
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++count;
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}
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return UnitInterval { count > 1 ? (accu / count) : accu };
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}
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} // namespace vanetza
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#endif /* UNIT_INTERVAL_HPP_BG1EK7QX */
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