diff options
Diffstat (limited to 'src/corelib/kernel/qmath.h')
| -rw-r--r-- | src/corelib/kernel/qmath.h | 128 |
1 files changed, 86 insertions, 42 deletions
diff --git a/src/corelib/kernel/qmath.h b/src/corelib/kernel/qmath.h index 98251c0b57..72057ee16d 100644 --- a/src/corelib/kernel/qmath.h +++ b/src/corelib/kernel/qmath.h @@ -1,41 +1,5 @@ -/**************************************************************************** -** -** Copyright (C) 2016 The Qt Company Ltd. -** Contact: https://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 The Qt Company Ltd. +// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only #ifndef QMATH_H #define QMATH_H @@ -135,6 +99,72 @@ template <typename T> auto qSqrt(T v) return sqrt(v); } +namespace QtPrivate { +template <typename R, typename F> // For qfloat16 to specialize +struct QHypotType { using type = decltype(std::hypot(R(1), F(1))); }; + +// Implements hypot() without limiting number of arguments: +template <typename T> +class QHypotHelper +{ + T scale, total; + template <typename F> friend class QHypotHelper; + QHypotHelper(T first, T prior) : scale(first), total(prior) {} +public: + QHypotHelper(T first) : scale(qAbs(first)), total(1) {} + T result() const + { return qIsFinite(scale) ? scale > 0 ? scale * T(qSqrt(total)) : T(0) : scale; } + + template<typename F, typename ...Fs> + auto add(F first, Fs... rest) const + { return add(first).add(rest...); } + + template<typename F, typename R = typename QHypotType<T, F>::type> + QHypotHelper<R> add(F next) const + { + if (qIsInf(scale) || (qIsNaN(scale) && !qIsInf(next))) + return QHypotHelper<R>(scale, R(1)); + if (qIsNaN(next)) + return QHypotHelper<R>(next, R(1)); + const R val = qAbs(next); + if (!(scale > 0) || qIsInf(next)) + return QHypotHelper<R>(val, R(1)); + if (!(val > 0)) + return QHypotHelper<R>(scale, total); + if (val > scale) { + const R ratio = scale / next; + return QHypotHelper<R>(val, total * ratio * ratio + R(1)); + } + const R ratio = next / scale; + return QHypotHelper<R>(scale, total + ratio * ratio); + } +}; +} // QtPrivate + +template<typename F, typename ...Fs> +auto qHypot(F first, Fs... rest) +{ + return QtPrivate::QHypotHelper<F>(first).add(rest...).result(); +} + +// However, where possible, use the standard library implementations: +template <typename Tx, typename Ty> +auto qHypot(Tx x, Ty y) +{ + // C99 has hypot(), hence C++11 has std::hypot() + using std::hypot; + return hypot(x, y); +} + +#if defined(__cpp_lib_hypot) && __cpp_lib_hypot >= 201603L // Expected to be true +template <typename Tx, typename Ty, typename Tz> +auto qHypot(Tx x, Ty y, Tz z) +{ + using std::hypot; + return hypot(x, y, z); +} +#endif // else: no need to over-ride the arbitrarily-many-arg form + template <typename T> auto qLn(T v) { using std::log; @@ -229,7 +259,7 @@ inline qreal qFastCos(qreal x) constexpr inline float qDegreesToRadians(float degrees) { - return degrees * float(M_PI/180); + return degrees * float(M_PI / 180); } constexpr inline double qDegreesToRadians(double degrees) @@ -250,7 +280,7 @@ constexpr inline double qDegreesToRadians(T degrees) constexpr inline float qRadiansToDegrees(float radians) { - return radians * float(180/M_PI); + return radians * float(180 / M_PI); } constexpr inline double qRadiansToDegrees(double radians) @@ -268,7 +298,8 @@ constexpr inline long double qRadiansToDegrees(long double radians) // using integral datatypes... namespace QtPrivate { -constexpr inline quint32 qConstexprNextPowerOfTwo(quint32 v) { +constexpr inline quint32 qConstexprNextPowerOfTwo(quint32 v) +{ v |= v >> 1; v |= v >> 2; v |= v >> 4; @@ -278,7 +309,8 @@ constexpr inline quint32 qConstexprNextPowerOfTwo(quint32 v) { return v; } -constexpr inline quint64 qConstexprNextPowerOfTwo(quint64 v) { +constexpr inline quint64 qConstexprNextPowerOfTwo(quint64 v) +{ v |= v >> 1; v |= v >> 2; v |= v >> 4; @@ -302,6 +334,7 @@ constexpr inline quint64 qConstexprNextPowerOfTwo(qint64 v) constexpr inline quint32 qNextPowerOfTwo(quint32 v) { + Q_ASSERT(static_cast<qint32>(v) >= 0); // There is a next power of two #if defined(__cpp_lib_int_pow2) && __cpp_lib_int_pow2 >= 202002L return std::bit_ceil(v + 1); #elif defined(QT_HAS_BUILTIN_CLZ) @@ -315,6 +348,7 @@ constexpr inline quint32 qNextPowerOfTwo(quint32 v) constexpr inline quint64 qNextPowerOfTwo(quint64 v) { + Q_ASSERT(static_cast<qint64>(v) >= 0); // There is a next power of two #if defined(__cpp_lib_int_pow2) && __cpp_lib_int_pow2 >= 202002L return std::bit_ceil(v + 1); #elif defined(QT_HAS_BUILTIN_CLZLL) @@ -336,6 +370,16 @@ constexpr inline quint64 qNextPowerOfTwo(qint64 v) return qNextPowerOfTwo(quint64(v)); } +constexpr inline unsigned long qNextPowerOfTwo(unsigned long v) +{ + return qNextPowerOfTwo(QIntegerForSizeof<long>::Unsigned(v)); +} + +constexpr inline unsigned long qNextPowerOfTwo(long v) +{ + return qNextPowerOfTwo(QIntegerForSizeof<long>::Unsigned(v)); +} + QT_END_NAMESPACE #endif // QMATH_H |