diff options
Diffstat (limited to 'src/corelib/global/q20algorithm.h')
| -rw-r--r-- | src/corelib/global/q20algorithm.h | 163 |
1 files changed, 119 insertions, 44 deletions
diff --git a/src/corelib/global/q20algorithm.h b/src/corelib/global/q20algorithm.h index 3024e89c6d..24d801b2cd 100644 --- a/src/corelib/global/q20algorithm.h +++ b/src/corelib/global/q20algorithm.h @@ -1,41 +1,5 @@ -/**************************************************************************** -** -** Copyright (C) 2021 Klarälvdalens Datakonsult AB, a KDAB Group company, info@kdab.com, author Marc Mutz <marc.mutz@kdab.com> -** Contact: http://www.qt.io/licensing/ -** -** This file is part of the QtCore module of the Qt Toolkit. -** -** $QT_BEGIN_LICENSE:LGPL$ -** Commercial License Usage -** Licensees holding valid commercial Qt licenses may use this file in -** accordance with the commercial license agreement provided with the -** Software or, alternatively, in accordance with the terms contained in -** a written agreement between you and The Qt Company. For licensing terms -** and conditions see https://www.qt.io/terms-conditions. For further -** information use the contact form at https://www.qt.io/contact-us. -** -** GNU Lesser General Public License Usage -** Alternatively, this file may be used under the terms of the GNU Lesser -** General Public License version 3 as published by the Free Software -** Foundation and appearing in the file LICENSE.LGPL3 included in the -** packaging of this file. Please review the following information to -** ensure the GNU Lesser General Public License version 3 requirements -** will be met: https://www.gnu.org/licenses/lgpl-3.0.html. -** -** GNU General Public License Usage -** Alternatively, this file may be used under the terms of the GNU -** General Public License version 2.0 or (at your option) the GNU General -** Public license version 3 or any later version approved by the KDE Free -** Qt Foundation. The licenses are as published by the Free Software -** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3 -** included in the packaging of this file. Please review the following -** information to ensure the GNU General Public License requirements will -** be met: https://www.gnu.org/licenses/gpl-2.0.html and -** https://www.gnu.org/licenses/gpl-3.0.html. -** -** $QT_END_LICENSE$ -** -****************************************************************************/ +// Copyright (C) 2021 Klarälvdalens Datakonsult AB, a KDAB Group company, info@kdab.com, author Marc Mutz <marc.mutz@kdab.com> +// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only #ifndef Q20ALGORITHM_H #define Q20ALGORITHM_H @@ -48,9 +12,9 @@ // W A R N I N G // ------------- // -// This file is not part of the Qt API. Types and functions defined -// in this file will behave exactly as their std counterparts. You -// may use these definitions in your own code, but be aware that we +// This file is not part of the Qt API. Types and functions defined in this +// file can reliably be replaced by their std counterparts, once available. +// You may use these definitions in your own code, but be aware that we // will remove them once Qt depends on the C++ version that supports // them in namespace std. There will be NO deprecation warning, the // definitions will JUST go away. @@ -62,6 +26,117 @@ QT_BEGIN_NAMESPACE +namespace q20 { +// like std::<algorithm> (ie. not ranged, but constexpr) +#ifdef __cpp_lib_constexpr_algorithms +using std::copy; +using std::copy_if; +using std::copy_n; +using std::fill; +using std::fill_n; +using std::is_sorted_until; +using std::is_sorted; +using std::transform; +#else +template <typename InputIterator, typename OutputIterator> +constexpr OutputIterator +copy(InputIterator first, InputIterator last, OutputIterator dest) +{ + while (first != last) { + *dest = *first; + ++first; + ++dest; + } + return dest; +} + +template <typename InputIterator, typename OutputIterator, typename UnaryPredicate> +constexpr OutputIterator +copy_if(InputIterator first, InputIterator last, OutputIterator dest, UnaryPredicate pred) +{ + while (first != last) { + if (pred(*first)) { + *dest = *first; + ++dest; + } + ++first; + } + return dest; +} + +template <typename InputIterator, typename Size, typename OutputIterator> +constexpr OutputIterator +copy_n(InputIterator first, Size n, OutputIterator dest) +{ + while (n > Size{0}) { + *dest = *first; + ++first; + ++dest; + --n; + } + return dest; +} + +template <typename ForwardIterator, typename Value> +constexpr void +fill(ForwardIterator first, ForwardIterator last, const Value &value) +{ + while (first != last) { + *first = value; + ++first; + } +} + +template <typename OutputIterator, typename Size, typename Value> +constexpr OutputIterator +fill_n(OutputIterator first, Size n, const Value &value) +{ + while (n > Size{0}) { + *first = value; + ++first; + --n; + } + return first; +} + +template <typename ForwardIterator, typename BinaryPredicate = std::less<>> +constexpr ForwardIterator +is_sorted_until(ForwardIterator first, ForwardIterator last, BinaryPredicate p = {}) +{ + if (first == last) + return first; + auto prev = first; + while (++first != last) { + if (p(*first, *prev)) + return first; + prev = first; + } + return first; +} + +template <typename ForwardIterator, typename BinaryPredicate = std::less<>> +constexpr bool is_sorted(ForwardIterator first, ForwardIterator last, BinaryPredicate p = {}) +{ + return q20::is_sorted_until(first, last, p) == last; +} + +template <typename InputIterator, typename OutputIterator, typename UnaryFunction> +constexpr OutputIterator +transform(InputIterator first, InputIterator last, OutputIterator dest, UnaryFunction op) +{ + while (first != last) { + *dest = op(*first); + ++first; + ++dest; + } + return dest; +} + +// binary transform missing on purpose (no users) + +#endif +} + namespace q20::ranges { // like std::ranges::{any,all,none}_of, just unconstrained, so no range-overload #ifdef __cpp_lib_ranges @@ -72,7 +147,7 @@ using std::ranges::none_of; [[maybe_unused]] inline constexpr struct { // Niebloid template <typename InputIterator, typename Sentinel, typename Predicate, typename Projection = q20::identity> - constexpr bool operator()(InputIterator first, Sentinel last, Predicate pred, Projection proj = {}) const + [[maybe_unused]] constexpr bool operator()(InputIterator first, Sentinel last, Predicate pred, Projection proj = {}) const { while (first != last) { if (std::invoke(pred, std::invoke(proj, *first))) @@ -85,7 +160,7 @@ using std::ranges::none_of; [[maybe_unused]] inline constexpr struct { // Niebloid template <typename InputIterator, typename Sentinel, typename Predicate, typename Projection = q20::identity> - constexpr bool operator()(InputIterator first, Sentinel last, Predicate pred, Projection proj = {}) const + [[maybe_unused]] constexpr bool operator()(InputIterator first, Sentinel last, Predicate pred, Projection proj = {}) const { while (first != last) { if (!std::invoke(pred, std::invoke(proj, *first))) @@ -98,7 +173,7 @@ using std::ranges::none_of; [[maybe_unused]] inline constexpr struct { // Niebloid template <typename InputIterator, typename Sentinel, typename Predicate, typename Projection = q20::identity> - constexpr bool operator()(InputIterator first, Sentinel last, Predicate pred, Projection proj = {}) const + [[maybe_unused]] constexpr bool operator()(InputIterator first, Sentinel last, Predicate pred, Projection proj = {}) const { while (first != last) { if (std::invoke(pred, std::invoke(proj, *first))) |