/**************************************************************************** ** ** 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 #include // for std::generate #include // 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 using IfValidUInt = typename std::enable_if::value && sizeof(UInt) >= sizeof(uint), bool>::type; public: QRandomGenerator(quint32 seedValue = 1) : QRandomGenerator(&seedValue, 1) {} template 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::digits; x >>= std::numeric_limits::digits - std::numeric_limits::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 = true> void fillRange(UInt *buffer, qsizetype count) { _fillRange(buffer, buffer + count); } template = true> void fillRange(UInt (&buffer)[N]) { _fillRange(buffer, buffer + N); } // API like std::seed_seq template 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::min(); } static Q_DECL_CONSTEXPR result_type max() { return std::numeric_limits::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; 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::type buffer; RandomEngine &engine() { return reinterpret_cast(buffer); } const RandomEngine &engine() const { return reinterpret_cast(buffer); } #endif Q_STATIC_ASSERT_X(std::is_trivially_destructible::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 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::min(); } static Q_DECL_CONSTEXPR result_type max() { return std::numeric_limits::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