1 files changed, 95 insertions, 0 deletions
diff --git a/src/libs/utils/ranges.h b/src/libs/utils/ranges.h
new file mode 100644
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+++ b/src/libs/utils/ranges.h
@@ -0,0 +1,95 @@
+// 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