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