include/QtCore/qalgorithms.h

0001 // Copyright (C) 2020 The Qt Company Ltd.
0002 // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
0003 // Qt-Security score:significant reason:default
0004
0005 #ifndef QALGORITHMS_H
0006 #define QALGORITHMS_H
0007
0008 #if 0
0009 #pragma qt_class(QtAlgorithms)
0010 #endif
0011
0012 #include <QtCore/qglobal.h>
0013 #include <QtCore/q20bit.h>
0014 #include <QtCore/q20functional.h>
0015 #include <type_traits>
0016
0017 #define QT_HAS_CONSTEXPR_BITOPS
0018
0019 QT_BEGIN_NAMESPACE
0020
0021 template <typename ForwardIterator>
0022 Q_OUTOFLINE_TEMPLATE void qDeleteAll(ForwardIterator begin, ForwardIterator end)
0023 {
0024     while (begin != end) {
0025         delete *begin;
0026         ++begin;
0027     }
0028 }
0029
0030 template <typename Container>
0031 inline void qDeleteAll(const Container &c)
0032 {
0033     qDeleteAll(c.begin(), c.end());
0034 }
0035
0036
0037 Q_DECL_CONST_FUNCTION constexpr inline uint qPopulationCount(quint32 v) noexcept
0038 {
0039     return q20::popcount(v);
0040 }
0041
0042 Q_DECL_CONST_FUNCTION constexpr inline uint qPopulationCount(quint8 v) noexcept
0043 {
0044     return q20::popcount(v);
0045 }
0046
0047 Q_DECL_CONST_FUNCTION constexpr inline uint qPopulationCount(quint16 v) noexcept
0048 {
0049     return q20::popcount(v);
0050 }
0051
0052 Q_DECL_CONST_FUNCTION constexpr inline uint qPopulationCount(quint64 v) noexcept
0053 {
0054     return q20::popcount(v);
0055 }
0056
0057 Q_DECL_CONST_FUNCTION constexpr inline uint qPopulationCount(long unsigned int v) noexcept
0058 {
0059     return q20::popcount(v);
0060 }
0061
0062 constexpr inline uint qCountTrailingZeroBits(quint32 v) noexcept
0063 {
0064     return q20::countr_zero(v);
0065 }
0066
0067 constexpr inline uint qCountTrailingZeroBits(quint8 v) noexcept
0068 {
0069     return q20::countr_zero(v);
0070 }
0071
0072 constexpr inline uint qCountTrailingZeroBits(quint16 v) noexcept
0073 {
0074     return q20::countr_zero(v);
0075 }
0076
0077 constexpr inline uint qCountTrailingZeroBits(quint64 v) noexcept
0078 {
0079     return q20::countr_zero(v);
0080 }
0081
0082 constexpr inline uint qCountTrailingZeroBits(unsigned long v) noexcept
0083 {
0084     return q20::countr_zero(v);
0085 }
0086
0087 constexpr inline uint qCountLeadingZeroBits(quint32 v) noexcept
0088 {
0089     return q20::countl_zero(v);
0090 }
0091
0092 constexpr inline uint qCountLeadingZeroBits(quint8 v) noexcept
0093 {
0094     return q20::countl_zero(v);
0095 }
0096
0097 constexpr inline uint qCountLeadingZeroBits(quint16 v) noexcept
0098 {
0099     return q20::countl_zero(v);
0100 }
0101
0102 constexpr inline uint qCountLeadingZeroBits(quint64 v) noexcept
0103 {
0104     return q20::countl_zero(v);
0105 }
0106
0107 constexpr inline uint qCountLeadingZeroBits(unsigned long v) noexcept
0108 {
0109     return q20::countl_zero(v);
0110 }
0111
0112 template <typename InputIterator, typename Result, typename Separator = Result,
0113           typename Projection = q20::identity>
0114 Result qJoin(InputIterator first, InputIterator last, Result init, const Separator &separator = {},
0115              Projection p = {})
0116 {
0117     if (first != last) {
0118         init += std::invoke(p, *first);
0119         ++first;
0120     }
0121
0122     while (first != last) {
0123         init += separator;
0124         init += std::invoke(p, *first);
0125         ++first;
0126     }
0127
0128     return init;
0129 }
0130
0131 namespace QtPrivate {
0132
0133 template <typename T>
0134 constexpr
0135 std::enable_if_t<std::conjunction_v<std::is_integral<T>, std::is_unsigned<T>>, int>
0136 log2i(T x)
0137 {
0138     // Integral -> int version of std::log2():
0139     Q_ASSERT(x > 0); // Q_PRE
0140     // C++20: return std::bit_width(x) - 1
0141     return int(sizeof(T) * 8 - 1 - qCountLeadingZeroBits(x));
0142 }
0143
0144 } // namespace QtPrivate
0145
0146 QT_END_NAMESPACE
0147
0148 #endif // QALGORITHMS_H