| 1 | // Copyright (C) 2021 The Qt Company Ltd. |
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| 2 | // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only |
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| 3 | #ifndef Q20ITERATOR_H |
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| 4 | #define Q20ITERATOR_H |
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| 5 | |
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| 6 | #include <QtCore/qglobal.h> |
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| 7 | |
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| 8 | #include <iterator> |
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| 9 | |
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| 10 | // |
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| 11 | // W A R N I N G |
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| 12 | // ------------- |
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| 13 | // |
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| 14 | // This file is not part of the Qt API. Types and functions defined in this |
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| 15 | // file can reliably be replaced by their std counterparts, once available. |
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| 16 | // You may use these definitions in your own code, but be aware that we |
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| 17 | // will remove them once Qt depends on the C++ version that supports |
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| 18 | // them in namespace std. There will be NO deprecation warning, the |
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| 19 | // definitions will JUST go away. |
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| 20 | // |
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| 21 | // If you can't agree to these terms, don't use these definitions! |
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| 22 | // |
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| 23 | // We mean it. |
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| 24 | // |
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| 25 | |
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| 26 | QT_BEGIN_NAMESPACE |
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| 27 | |
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| 28 | // like std::ssize |
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| 29 | namespace q20 { |
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| 30 | #ifdef __cpp_lib_ssize |
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| 31 | using std::ssize; |
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| 32 | #else |
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| 33 | template<class C> constexpr auto ssize(const C &c) |
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| 34 | -> std::common_type_t<std::ptrdiff_t, std::make_signed_t<decltype(c.size())>> |
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| 35 | { return static_cast<std::common_type_t<std::ptrdiff_t, std::make_signed_t<decltype(c.size())>>>(c.size()); } |
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| 36 | |
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| 37 | template<class T, std::ptrdiff_t N> constexpr std::ptrdiff_t ssize(const T (&)[N]) noexcept |
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| 38 | { return N; } |
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| 39 | #endif |
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| 40 | } // namespace q20 |
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| 41 | |
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| 42 | // like std::iter_reference_t |
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| 43 | namespace q20 { |
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| 44 | #ifdef __cpp_lib_ranges |
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| 45 | using std::iter_reference_t; |
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| 46 | #else |
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| 47 | template <typename Dereferencable> // unconstrained (constraint requires concepts) |
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| 48 | using iter_reference_t = decltype(*std::declval<Dereferencable&>()); |
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| 49 | #endif // __cpp_lib_ranges |
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| 50 | } // namespace q20 |
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| 51 | |
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| 52 | QT_END_NAMESPACE |
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| 53 | |
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| 54 | #endif /* Q20ITERATOR_H */ |
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| 55 | |
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