🛠️🐜 Antkeeper superbuild with dependencies included
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107 lines
3.5 KiB
107 lines
3.5 KiB
#ifndef AL_SPAN_H
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#define AL_SPAN_H
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#include <cstddef>
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#include <array>
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#include <type_traits>
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#include <initializer_list>
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namespace al {
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template<typename T>
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constexpr auto size(T &cont) -> decltype(cont.size())
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{ return cont.size(); }
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template<typename T>
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constexpr auto size(const T &cont) -> decltype(cont.size())
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{ return cont.size(); }
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template<typename T, size_t N>
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constexpr size_t size(T (&)[N]) noexcept
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{ return N; }
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template<typename T>
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constexpr size_t size(std::initializer_list<T> list) noexcept
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{ return list.size(); }
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template<typename T>
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constexpr auto data(T &cont) -> decltype(cont.data())
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{ return cont.data(); }
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template<typename T>
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constexpr auto data(const T &cont) -> decltype(cont.data())
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{ return cont.data(); }
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template<typename T, size_t N>
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constexpr T* data(T (&arr)[N]) noexcept
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{ return arr; }
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template<typename T>
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constexpr const T* data(std::initializer_list<T> list) noexcept
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{ return list.begin(); }
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template<typename T>
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class span {
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public:
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using element_type = T;
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using value_type = typename std::remove_cv<T>::type;
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using index_type = size_t;
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using difference_type = ptrdiff_t;
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using pointer = T*;
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using const_pointer = const T*;
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using reference = T&;
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using const_reference = const T&;
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using iterator = pointer;
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using const_iterator = const_pointer;
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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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constexpr span() noexcept = default;
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constexpr span(pointer ptr, index_type count) : mData{ptr}, mCount{count} { }
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constexpr span(pointer first, pointer last) : mData{first}, mCount{std::distance(first, last)} { }
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template<size_t N>
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constexpr span(element_type (&arr)[N]) noexcept : span{al::data(arr), al::size(arr)} { }
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template<size_t N>
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constexpr span(std::array<value_type,N> &arr) noexcept : span{al::data(arr), al::size(arr)} { }
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template<size_t N>
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constexpr span(const std::array<value_type,N> &arr) noexcept : span{al::data(arr), al::size(arr)} { }
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template<typename U>
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constexpr span(U &cont) : span{al::data(cont), al::size(cont)} { }
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template<typename U>
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constexpr span(const U &cont) : span{al::data(cont), al::size(cont)} { }
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constexpr span(const span&) noexcept = default;
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span& operator=(const span &rhs) noexcept = default;
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constexpr reference front() const { return mData[0]; }
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constexpr reference back() const { return mData[mCount-1]; }
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constexpr reference operator[](index_type idx) const { return mData[idx]; }
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constexpr pointer data() const noexcept { return mData; }
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constexpr index_type size() const noexcept { return mCount; }
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constexpr index_type size_bytes() const noexcept { return mCount * sizeof(value_type); }
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constexpr bool empty() const noexcept { return mCount == 0; }
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constexpr iterator begin() const noexcept { return mData; }
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constexpr iterator end() const noexcept { return mData + mCount; }
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constexpr const_iterator cbegin() const noexcept { return mData; }
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constexpr const_iterator cend() const noexcept { return mData + mCount; }
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constexpr reverse_iterator rbegin() const noexcept { return end(); }
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constexpr reverse_iterator rend() const noexcept { return begin(); }
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constexpr const_reverse_iterator crbegin() const noexcept { return cend(); }
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constexpr const_reverse_iterator crend() const noexcept { return cbegin(); }
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private:
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pointer mData{nullptr};
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index_type mCount{0u};
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};
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} // namespace al
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#endif /* AL_SPAN_H */
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