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// Copyright (C) 2023 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0+ OR GPL-3.0 WITH Qt-GPL-exception-1.0
#pragma once
#if __cplusplus >= 202002L
#include <ranges>
namespace Utils {
namespace ranges {
using std::ranges::reverse_view;
}
namespace views {
using std::views::reverse;
}
} // namespace Utils
#else
#include <stdexcept>
namespace Utils {
namespace ranges {
template <typename Container>
class reverse_view
{
public:
using value_type = typename Container::value_type;
using size_type = typename Container::size_type;
using Type = value_type;
using pointer = Type *;
using const_pointer = const Type *;
using reference = Type &;
using const_reference = const Type &;
using reverse_iterator = typename Container::iterator;
using iterator = std::reverse_iterator<reverse_iterator>;
using const_reverse_iterator = typename Container::const_iterator;
using const_iterator = std::reverse_iterator<const_reverse_iterator>;
using Iterator = iterator;
using ConstIterator = const_iterator;
reverse_view(const Container &k) : d(&k) {}
const_reverse_iterator rbegin() const noexcept { return d->begin(); }
const_reverse_iterator rend() const noexcept { return d->end(); }
const_reverse_iterator crbegin() const noexcept { return d->begin(); }
const_reverse_iterator crend() const noexcept { return d->end(); }
const_iterator begin() const noexcept { return const_iterator(rend()); }
const_iterator end() const noexcept { return const_iterator(rbegin()); }
const_iterator cbegin() const noexcept { return const_iterator(rend()); }
const_iterator cend() const noexcept { return const_iterator(rbegin()); }
const_iterator constBegin() const noexcept { return const_iterator(rend()); }
const_iterator constEnd() const noexcept { return const_iterator(rbegin()); }
const_reference front() const noexcept { return *cbegin(); }
const_reference back() const noexcept { return *crbegin(); }
[[nodiscard]] size_type size() const noexcept { return d->size(); }
[[nodiscard]] bool empty() const noexcept { return d->size() == 0; }
explicit operator bool() const { return d->size(); }
const_reference operator[](size_type idx) const
{
if (idx < size())
return *(begin() + idx);
throw std::out_of_range("bad index in reverse side");
}
private:
const Container *d;
};
} // namespace ranges
namespace views {
constexpr struct {} reverse;
template <typename T>
inline ranges::reverse_view<T> operator|(const T &container, const decltype(reverse)&)
{
return ranges::reverse_view(container);
}
} // namsepace views
} // namespace Utils
#endif
|
