vladislavbelov
6ca43f056d
Patch By: phosit Differential Revision: https://code.wildfiregames.com/D4677 This was SVN commit r27106.
86 lines
2.5 KiB
C++
86 lines
2.5 KiB
C++
/* Copyright (C) 2022 Wildfire Games.
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* This file is part of 0 A.D.
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*
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* 0 A.D. is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 2 of the License, or
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* (at your option) any later version.
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*
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* 0 A.D. is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with 0 A.D. If not, see <http://www.gnu.org/licenses/>.
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*/
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#ifndef INCLUDED_PS_SPAN
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#define INCLUDED_PS_SPAN
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#include <cstddef>
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#include <iterator>
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#include <type_traits>
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namespace PS
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{
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/**
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* Simplifed version of std::span (C++20) as we don't support the original one
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* yet. The naming intentionally follows the STL version to make the future
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* replacement easier with less blame changing.
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* It supports only very basic subset of std::span functionality.
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* TODO: remove as soon as std::span become available.
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*/
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template<typename T>
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class span
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{
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public:
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using element_type = T;
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using value_type = std::remove_cv_t<T>;
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using size_type = size_t;
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using pointer = T*;
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using reference = T&;
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using iterator = pointer;
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constexpr span()
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: m_Pointer(nullptr), m_Extent(0) {}
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constexpr span(iterator first, size_type extent)
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: m_Pointer(first), m_Extent(extent) {}
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constexpr span(iterator first, iterator last)
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: m_Pointer(first), m_Extent(static_cast<size_type>(last - first)) {}
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template<typename OtherT, size_t N>
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constexpr span(const std::array<OtherT, N>& arr)
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: m_Pointer(arr.data()), m_Extent(arr.size()) {}
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constexpr span(const span& other) = default;
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constexpr span& operator=(const span& other) = default;
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~span() = default;
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constexpr size_type size() const { return m_Extent; }
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constexpr bool empty() const { return size() == 0; }
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constexpr reference operator[](size_type index) const { return *(m_Pointer + index); }
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constexpr pointer data() const { return m_Pointer; }
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constexpr iterator begin() const { return m_Pointer; }
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constexpr iterator end() const { return m_Pointer + m_Extent; }
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constexpr span subspan(size_type offset) const { return {m_Pointer + offset, m_Extent - offset}; }
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private:
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pointer m_Pointer;
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size_type m_Extent;
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};
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template<typename T, size_t N>
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span(const std::array<T, N>&) -> span<const T>;
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} // namespace PS
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#endif // INCLUDED_PS_SPAN
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