Differential D4677 Diff 20618 source/ps/containers/Span.h

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source/ps/containers/Span.h

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	* TODO: remove as soon as std::span become available.			* TODO: remove as soon as std::span become available.
	*/			*/
	template<typename T>			template<typename T>
	class span			class span
	{			{
	public:			public:
	using element_type = T;			using element_type = T;
	using value_type = std::remove_cv_t<T>;			using value_type = std::remove_cv_t<T>;
	using size_type = std::size_t;			using size_type = size_t;
	using pointer = T*;			using pointer = T*;
	using reference = T&;			using reference = T&;
	using iterator = pointer;			using iterator = pointer;

	constexpr span()			constexpr span()
	: m_Pointer(nullptr), m_Extent(0) {}			: m_Pointer(nullptr), m_Extent(0) {}

	constexpr span(iterator first, size_type extent)			constexpr span(iterator first, size_type extent)
	: m_Pointer(first), m_Extent(extent) {}			: m_Pointer(first), m_Extent(extent) {}

	constexpr span(iterator first, iterator last)			constexpr span(iterator first, iterator last)
	: m_Pointer(first), m_Extent(static_cast<size_type>(last - first)) {}			: m_Pointer(first), m_Extent(static_cast<size_type>(last - first)) {}

				template<typename OtherT, size_t n>
				StanUnsubmitted Not Done Inline Actions std::size_t not sure about that one, we seem to use size_t in most places Stan: std::size_t not sure about that one, we seem to use size_t in most places
				constexpr span(const std::array<OtherT, n>& arr)
				: m_Pointer(arr.data()), m_Extent(arr.size()) {}

	constexpr span(const span& other) = default;			constexpr span(const span& other) = default;

	constexpr span& operator=(const span& other) = default;			constexpr span& operator=(const span& other) = default;

	~span() = default;			~span() = default;

	constexpr size_type size() const { return m_Extent; }			constexpr size_type size() const { return m_Extent; }
	constexpr bool empty() const { return size() == 0; }			constexpr bool empty() const { return size() == 0; }
	constexpr reference operator[](size_type index) const { return *(m_Pointer + index); }			constexpr reference operator[](size_type index) const { return *(m_Pointer + index); }
	constexpr pointer data() const { return m_Pointer; }			constexpr pointer data() const { return m_Pointer; }

	constexpr iterator begin() const { return m_Pointer; }			constexpr iterator begin() const { return m_Pointer; }
	constexpr iterator end() const { return m_Pointer + m_Extent; }			constexpr iterator end() const { return m_Pointer + m_Extent; }

				constexpr span subspan(size_type offset) const { return {m_Pointer + offset, m_Extent - offset}; }

	private:			private:
	pointer m_Pointer;			pointer m_Pointer;
	size_type m_Extent;			size_type m_Extent;
	};			};

				template<typename T, size_t n>
				span(const std::array<T, n>&) -> span<const T>;

	} // namespace PS			} // namespace PS

	#endif // INCLUDED_PS_SPAN			#endif // INCLUDED_PS_SPAN