66 lines
No EOL
1.9 KiB
C++
66 lines
No EOL
1.9 KiB
C++
//
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// Yet Another POD-Bot, based on PODBot by Markus Klinge ("CountFloyd").
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// Copyright (c) YaPB Development Team.
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//
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// This software is licensed under the BSD-style license.
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// Additional exceptions apply. For full license details, see LICENSE.txt or visit:
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// https://yapb.ru/license
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//
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#pragma once
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#include <time.h>
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#include <crlib/cr-basic.h>
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CR_NAMESPACE_BEGIN
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// random number generator see: https://github.com/preshing/RandomSequence/
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class Random final : public Singleton <Random> {
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private:
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uint32 m_index, m_offset;
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uint64 m_divider;
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public:
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explicit Random () {
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const auto base = static_cast <uint32> (time (nullptr));
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const auto offset = base + 1;
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m_index = premute (premute (base) + 0x682f0161);
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m_offset = premute (premute (offset) + 0x46790905);
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m_divider = (static_cast <uint64> (1)) << 32;
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}
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~Random () = default;
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private:
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uint32 premute (uint32 index) {
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static constexpr auto prime = 4294967291u;
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if (index >= prime) {
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return index;
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}
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const uint32 residue = (static_cast <uint64> (index) * index) % prime;
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return (index <= prime / 2) ? residue : prime - residue;
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}
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uint32 generate () {
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return premute ((premute (m_index++) + m_offset) ^ 0x5bf03635);
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}
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public:
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template <typename U> U int_ (U low, U high) {
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return static_cast <U> (generate () * (static_cast <double> (high) - static_cast <double> (low) + 1.0) / m_divider + static_cast <double> (low));
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}
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float float_ (float low, float high) {
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return static_cast <float> (generate () * (static_cast <double> (high) - static_cast <double> (low)) / (m_divider - 1) + static_cast <double> (low));
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}
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template <typename U> bool chance (const U max, const U maxChance = 100) {
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return int_ <U> (0, maxChance) < max;
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}
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};
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// expose global random generator
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static auto &rg = Random::get ();
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CR_NAMESPACE_END |