qt-everywhere-src-5.15.1/qtbase/src/corelib/global/qrandom.h - orbit - Git at Google

 /****************************************************************************
 **
 ** 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
	/****************************************************************************
	**
	** 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