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1d19bd11d0
This has the same interval ((0,N]) that the client function does The devs have referenced this in a few posts talking about mechanics.
111 lines
3.1 KiB
C++
111 lines
3.1 KiB
C++
/* EQEMu: Everquest Server Emulator
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Copyright (C) 2001-2014 EQEMu Development Team (http://eqemulator.net)
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; version 2 of the License.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY except by those people which sell it, which
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are required to give you total support for your newly bought product;
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without even the implied warranty of MERCHANTABILITY or FITNESS FOR
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A PARTICULAR PURPOSE. See the GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#ifndef __random_h__
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#define __random_h__
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#include <random>
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#include <utility>
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#include <algorithm>
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#include <iterator>
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#include <type_traits>
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/* This uses mt19937 seeded with the std::random_device
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* The idea is to have this be included as a member of another class
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* so mocking out for testing is easier
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* If you need to reseed random.Reseed()
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* Eventually this should be derived from an abstract base class
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*/
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namespace EQEmu {
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class Random {
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public:
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// AKA old MakeRandomInt
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int Int(int low, int high)
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{
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if (low > high)
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std::swap(low, high);
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return int_dist(m_gen, int_param_t(low, high)); // [low, high]
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}
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// AKA old MakeRandomFloat
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double Real(double low, double high)
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{
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if (low > high)
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std::swap(low, high);
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return real_dist(m_gen, real_param_t(low, high)); // [low, high)
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}
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// example Roll(50) would have a 50% success rate
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// Roll(100) 100%, etc
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// valid values 0-100 (well, higher works too but ...)
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bool Roll(const int required)
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{
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return Int(0, 99) < required;
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}
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// valid values 0.0 - 1.0
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bool Roll(const double required)
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{
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return Real(0.0, 1.0) <= required;
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}
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// same range as client's roll0
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// This is their main high level RNG function
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int Roll0(int max)
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{
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if (max - 1 > 0)
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return Int(0, max - 1);
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return 0;
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}
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// std::shuffle requires a RNG engine passed to it, so lets provide a wrapper to use our engine
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template<typename RandomAccessIterator>
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void Shuffle(RandomAccessIterator first, RandomAccessIterator last)
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{
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static_assert(std::is_same<std::random_access_iterator_tag,
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typename std::iterator_traits<RandomAccessIterator>::iterator_category>::value,
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"EQEmu::Random::Shuffle requires random access iterators");
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std::shuffle(first, last, m_gen);
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}
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void Reseed()
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{
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// We could do the seed_seq thing here too if we need better seeding
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// but that is mostly overkill for us, so just seed once
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std::random_device rd;
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m_gen.seed(rd());
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}
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Random()
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{
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Reseed();
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}
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private:
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typedef std::uniform_int_distribution<int>::param_type int_param_t;
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typedef std::uniform_real_distribution<double>::param_type real_param_t;
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std::mt19937 m_gen;
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std::uniform_int_distribution<int> int_dist;
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std::uniform_real_distribution<double> real_dist;
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};
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}
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#endif /* !__random_h__ */
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