| /**************************************************************************** |
| ** |
| ** Copyright (C) 2017 Intel Corporation. |
| ** 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. |
| ** |
| ** $QT_END_LICENSE$ |
| ** |
| ****************************************************************************/ |
| |
| #ifndef QRANDOM_H |
| #define QRANDOM_H |
| |
| #include <QtCore/qglobal.h> |
| #include <algorithm> // for std::generate |
| #include <random> // for std::mt19937 |
| |
| #ifdef min |
| # undef min |
| #endif |
| #ifdef max |
| # undef max |
| #endif |
| |
| QT_BEGIN_NAMESPACE |
| |
| class QRandomGenerator |
| { |
| // restrict the template parameters to unsigned integers 32 bits wide or larger |
| template <typename UInt> using IfValidUInt = |
| typename std::enable_if<std::is_unsigned<UInt>::value && sizeof(UInt) >= sizeof(uint), bool>::type; |
| public: |
| QRandomGenerator(quint32 seedValue = 1) |
| : QRandomGenerator(&seedValue, 1) |
| {} |
| template <qsizetype N> QRandomGenerator(const quint32 (&seedBuffer)[N]) |
| : QRandomGenerator(seedBuffer, seedBuffer + N) |
| {} |
| QRandomGenerator(const quint32 *seedBuffer, qsizetype len) |
| : QRandomGenerator(seedBuffer, seedBuffer + len) |
| {} |
| Q_CORE_EXPORT QRandomGenerator(std::seed_seq &sseq) noexcept; |
| Q_CORE_EXPORT QRandomGenerator(const quint32 *begin, const quint32 *end); |
| |
| // copy constructor & assignment operator (move unnecessary) |
| Q_CORE_EXPORT QRandomGenerator(const QRandomGenerator &other); |
| Q_CORE_EXPORT QRandomGenerator &operator=(const QRandomGenerator &other); |
| |
| friend Q_CORE_EXPORT bool operator==(const QRandomGenerator &rng1, const QRandomGenerator &rng2); |
| friend bool operator!=(const QRandomGenerator &rng1, const QRandomGenerator &rng2) |
| { |
| return !(rng1 == rng2); |
| } |
| |
| quint32 generate() |
| { |
| quint32 ret; |
| fillRange(&ret, 1); |
| return ret; |
| } |
| |
| quint64 generate64() |
| { |
| quint32 buf[2]; |
| fillRange(buf); |
| return buf[0] | (quint64(buf[1]) << 32); |
| } |
| |
| double generateDouble() |
| { |
| // IEEE 754 double precision has: |
| // 1 bit sign |
| // 10 bits exponent |
| // 53 bits mantissa |
| // In order for our result to be normalized in the range [0, 1), we |
| // need exactly 53 bits of random data. Use generate64() to get enough. |
| quint64 x = generate64(); |
| quint64 limit = Q_UINT64_C(1) << std::numeric_limits<double>::digits; |
| x >>= std::numeric_limits<quint64>::digits - std::numeric_limits<double>::digits; |
| return double(x) / double(limit); |
| } |
| |
| double bounded(double highest) |
| { |
| return generateDouble() * highest; |
| } |
| |
| quint32 bounded(quint32 highest) |
| { |
| quint64 value = generate(); |
| value *= highest; |
| value /= (max)() + quint64(1); |
| return quint32(value); |
| } |
| |
| quint32 bounded(quint32 lowest, quint32 highest) |
| { |
| Q_ASSERT(highest > lowest); |
| return bounded(highest - lowest) + lowest; |
| } |
| |
| int bounded(int highest) |
| { |
| Q_ASSERT(highest > 0); |
| return int(bounded(0U, quint32(highest))); |
| } |
| |
| int bounded(int lowest, int highest) |
| { |
| return bounded(highest - lowest) + lowest; |
| } |
| |
| template <typename UInt, IfValidUInt<UInt> = true> |
| void fillRange(UInt *buffer, qsizetype count) |
| { |
| _fillRange(buffer, buffer + count); |
| } |
| |
| template <typename UInt, size_t N, IfValidUInt<UInt> = true> |
| void fillRange(UInt (&buffer)[N]) |
| { |
| _fillRange(buffer, buffer + N); |
| } |
| |
| // API like std::seed_seq |
| template <typename ForwardIterator> |
| void generate(ForwardIterator begin, ForwardIterator end) |
| { |
| std::generate(begin, end, [this]() { return generate(); }); |
| } |
| |
| void generate(quint32 *begin, quint32 *end) |
| { |
| _fillRange(begin, end); |
| } |
| |
| // API like std:: random engines |
| typedef quint32 result_type; |
| result_type operator()() { return generate(); } |
| void seed(quint32 s = 1) { *this = { s }; } |
| void seed(std::seed_seq &sseq) noexcept { *this = { sseq }; } |
| Q_CORE_EXPORT void discard(unsigned long long z); |
| static Q_DECL_CONSTEXPR result_type min() { return std::numeric_limits<result_type>::min(); } |
| static Q_DECL_CONSTEXPR result_type max() { return std::numeric_limits<result_type>::max(); } |
| |
| static inline Q_DECL_CONST_FUNCTION QRandomGenerator *system(); |
| static inline Q_DECL_CONST_FUNCTION QRandomGenerator *global(); |
| static inline QRandomGenerator securelySeeded(); |
| |
| protected: |
| enum System {}; |
| QRandomGenerator(System); |
| |
| private: |
| Q_CORE_EXPORT void _fillRange(void *buffer, void *bufferEnd); |
| |
| friend class QRandomGenerator64; |
| struct SystemGenerator; |
| struct SystemAndGlobalGenerators; |
| using RandomEngine = std::mersenne_twister_engine<quint32, |
| 32,624,397,31,0x9908b0df,11,0xffffffff,7,0x9d2c5680,15,0xefc60000,18,1812433253>; |
| |
| union Storage { |
| uint dummy; |
| #ifdef Q_COMPILER_UNRESTRICTED_UNIONS |
| RandomEngine twister; |
| RandomEngine &engine() { return twister; } |
| const RandomEngine &engine() const { return twister; } |
| #else |
| std::aligned_storage<sizeof(RandomEngine), Q_ALIGNOF(RandomEngine)>::type buffer; |
| RandomEngine &engine() { return reinterpret_cast<RandomEngine &>(buffer); } |
| const RandomEngine &engine() const { return reinterpret_cast<const RandomEngine &>(buffer); } |
| #endif |
| |
| Q_STATIC_ASSERT_X(std::is_trivially_destructible<RandomEngine>::value, |
| "std::mersenne_twister not trivially destructible as expected"); |
| Q_DECL_CONSTEXPR Storage(); |
| }; |
| uint type; |
| Storage storage; |
| }; |
| |
| class QRandomGenerator64 : public QRandomGenerator |
| { |
| QRandomGenerator64(System); |
| public: |
| // unshadow generate() overloads, since we'll override. |
| using QRandomGenerator::generate; |
| quint64 generate() { return generate64(); } |
| |
| typedef quint64 result_type; |
| result_type operator()() { return generate64(); } |
| |
| #ifndef Q_QDOC |
| QRandomGenerator64(quint32 seedValue = 1) |
| : QRandomGenerator(seedValue) |
| {} |
| template <qsizetype N> QRandomGenerator64(const quint32 (&seedBuffer)[N]) |
| : QRandomGenerator(seedBuffer) |
| {} |
| QRandomGenerator64(const quint32 *seedBuffer, qsizetype len) |
| : QRandomGenerator(seedBuffer, len) |
| {} |
| QRandomGenerator64(std::seed_seq &sseq) noexcept |
| : QRandomGenerator(sseq) |
| {} |
| QRandomGenerator64(const quint32 *begin, const quint32 *end) |
| : QRandomGenerator(begin, end) |
| {} |
| QRandomGenerator64(const QRandomGenerator &other) : QRandomGenerator(other) {} |
| |
| void discard(unsigned long long z) |
| { |
| Q_ASSERT_X(z * 2 > z, "QRandomGenerator64::discard", |
| "Overflow. Are you sure you want to skip over 9 quintillion samples?"); |
| QRandomGenerator::discard(z * 2); |
| } |
| |
| static Q_DECL_CONSTEXPR result_type min() { return std::numeric_limits<result_type>::min(); } |
| static Q_DECL_CONSTEXPR result_type max() { return std::numeric_limits<result_type>::max(); } |
| static Q_DECL_CONST_FUNCTION Q_CORE_EXPORT QRandomGenerator64 *system(); |
| static Q_DECL_CONST_FUNCTION Q_CORE_EXPORT QRandomGenerator64 *global(); |
| static Q_CORE_EXPORT QRandomGenerator64 securelySeeded(); |
| #endif // Q_QDOC |
| }; |
| |
| inline QRandomGenerator *QRandomGenerator::system() |
| { |
| return QRandomGenerator64::system(); |
| } |
| |
| inline QRandomGenerator *QRandomGenerator::global() |
| { |
| return QRandomGenerator64::global(); |
| } |
| |
| QRandomGenerator QRandomGenerator::securelySeeded() |
| { |
| return QRandomGenerator64::securelySeeded(); |
| } |
| |
| QT_END_NAMESPACE |
| |
| #endif // QRANDOM_H |