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Began reimplementation of span. Basic constructors.
This commit is contained in:
Neil MacIntosh
parent
cec26a23b9
commit
d3929c59a0
@ -106,6 +106,7 @@ inline T narrow(U u)
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T t = narrow_cast<T>(u);
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if (static_cast<U>(t) != u)
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throw narrowing_error();
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#pragma warning(suppress:4127) // suppress warning from MSVC compiler about constant in if-test
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if (!details::is_same_signedness<T, U>::value && ((t < T{}) != (u < U{})))
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throw narrowing_error();
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return t;
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132
include/span.h
132
include/span.h
@ -21,16 +21,9 @@
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#include "gsl_assert.h"
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#include "gsl_util.h"
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#include <algorithm>
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#include <array>
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#include <cassert>
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#include <cstddef>
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#include <cstdint>
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#include <functional>
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#include <iterator>
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#include <limits>
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#include <new>
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#include <numeric>
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#include <iterator>
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#include <stdexcept>
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#include <type_traits>
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#include <utility>
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@ -79,6 +72,129 @@
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namespace gsl
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{
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// [views.constants], constants
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constexpr const std::ptrdiff_t dynamic_extent = -1;
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// [span], class template span
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template <class ElementType, std::ptrdiff_t Extent = dynamic_extent>
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class span {
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public:
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// constants and types
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using element_type = ElementType;
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using index_type = std::ptrdiff_t;
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using pointer = element_type*;
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using reference = element_type&;
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#if 0 // TODO
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using iterator = /*implementation-defined */;
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using const_iterator = /* implementation-defined */;
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using reverse_iterator = std::reverse_iterator<iterator>;
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using const_reverse_iterator = std::reverse_iterator<const_iterator>;
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#endif
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constexpr static const index_type extent = Extent;
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// [span.cons], span constructors, copy, assignment, and destructor
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constexpr span() noexcept : data_(nullptr), size_(0)
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{ static_assert(extent == dynamic_extent || extent == 0, "Cannot default initialize a fixed-length span."); }
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constexpr span(nullptr_t) noexcept : span() {}
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constexpr span(pointer ptr, index_type count) : data_(ptr), size_(count)
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{ Expects((!ptr && count == 0) || (ptr && count >= 0)); }
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#if 0 // TODO
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constexpr span(pointer firstElem, pointer lastElem);
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template <size_t N>
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constexpr span(element_type(&arr)[N]);
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template <size_t N>
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constexpr span(array<remove_const_t<element_type>, N>& arr);
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template <size_t N>
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constexpr span(const array<remove_const_t<element_type>, N>& arr);
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template <class Container>
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constexpr span(Container& cont);
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template <class Container>
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span(const Container&&) = delete;
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constexpr span(const span& other) noexcept = default;
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constexpr span(span&& other) noexcept = default;
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template <class OtherElementType, ptrdiff_t OtherExtent>
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constexpr span(const span<OtherElementType, OtherExtent>& other);
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template <class OtherElementType, ptrdiff_t OtherExtent>
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constexpr span(span<OtherElementType, OtherExtent>&& other);
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~span() noexcept = default;
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constexpr span& operator=(const span& other) noexcept = default;
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constexpr span& operator=(span&& other) noexcept = default;
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// [span.sub], span subviews
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template <ptrdiff_t Count>
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constexpr span<element_type, Count> first() const;
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template <ptrdiff_t Count>
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constexpr span<element_type, Count> last() const;
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template <ptrdiff_t Offset, ptrdiff_t Count = dynamic_extent>
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constexpr span<element_type, Count> subspan() const;
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constexpr span<element_type, dynamic_extent> first(index_type count) const;
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constexpr span<element_type, dynamic_extent> last(index_type count) const;
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constexpr span<element_type, dynamic_extent> subspan(index_type offset, index_type count = dynamic_extent) const;
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#endif
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// [span.obs], span observers
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constexpr index_type length() const noexcept { return size(); }
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constexpr index_type size() const noexcept { return size_; }
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constexpr index_type length_bytes() const noexcept { return size_bytes(); }
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constexpr index_type size_bytes() const noexcept { return size() * sizeof(element_type); }
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constexpr bool empty() const noexcept { return size() == 0; }
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#if 0 // TODO
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// [span.elem], span element access
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constexpr reference operator[](index_type idx) const;
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constexpr reference operator()(index_type idx) const;
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#endif
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constexpr pointer data() const noexcept { return data_; }
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#if 0 // TODO
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// [span.iter], span iterator support
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iterator begin() const noexcept;
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iterator end() const noexcept;
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const_iterator cbegin() const noexcept;
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const_iterator cend() const noexcept;
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reverse_iterator rbegin() const noexcept;
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reverse_iterator rend() const noexcept;
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const_reverse_iterator crbegin() const noexcept;
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const_reverse_iterator crend() const noexcept;
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#endif
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private:
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pointer data_;
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index_type size_;
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};
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#if 0 // TODO
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// [span.comparison], span comparison operators
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template <class ElementType, ptrdiff_t Extent>
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constexpr bool operator==(const span<ElementType, Extent>& l, const span<ElementType, Extent>& r) const noexcept;
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template <class ElementType, ptrdiff_t Extent>
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constexpr bool operator!=(const span<ElementType, Extent>& l, const span<ElementType, Extent>& r) const noexcept;
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template <class ElementType, ptrdiff_t Extent>
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constexpr bool operator<(const span<ElementType, Extent>& l, const span<ElementType, Extent>& r) const noexcept;
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template <class ElementType, ptrdiff_t Extent>
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constexpr bool operator<=(const span<ElementType, Extent>& l, const span<ElementType, Extent>& r) const noexcept;
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template <class ElementType, ptrdiff_t Extent>
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constexpr bool operator>(const span<ElementType, Extent>& l, const span<ElementType, Extent>& r) const noexcept;
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template <class ElementType, ptrdiff_t Extent>
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constexpr bool operator>=(const span<ElementType, Extent>& l, const span<ElementType, Extent>& r) const noexcept;
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#endif
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#if 0 // TODO
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// [span.objectrep], views of object representation
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template <class ElementType, ptrdiff_t Extent>
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constexpr span<const char, ((Extent == dynamic_extent) ? dynamic_extent : (sizeof(ElementType) * Extent))> as_bytes(span<ElementType, Extent> s) noexcept;
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template <class ElementType, ptrdiff_t Extent>
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constexpr span<char, ((Extent == dynamic_extent) ? dynamic_extent : (sizeof(ElementType) * Extent))> as_writeable_bytes(span<ElementType, Extent>) noexcept;
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#endif
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} // namespace gsl
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@ -39,7 +39,6 @@ struct DerivedClass : BaseClass
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SUITE(span_tests)
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{
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#if 0
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TEST(default_constructor)
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{
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{
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@ -116,6 +115,7 @@ SUITE(span_tests)
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}
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}
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#if 0
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TEST(from_nullptr_length_constructor)
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{
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{
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