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87 lines
2.5 KiB
C++
87 lines
2.5 KiB
C++
/*
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* This file is part of OpenTTD.
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* OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
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* OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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* See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
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*/
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/** @file random_func.cpp Implementation of the pseudo random generator. */
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#include "../stdafx.h"
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#include "random_func.hpp"
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#include "bitmath_func.hpp"
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#include <bit>
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#ifdef RANDOM_DEBUG
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#include "../network/network.h"
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#include "../network/network_server.h"
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#include "../network/network_internal.h"
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#include "../company_func.h"
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#include "../fileio_func.h"
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#include "../date_func.h"
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#endif /* RANDOM_DEBUG */
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#include "../safeguards.h"
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Randomizer _random, _interactive_random;
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/**
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* Generate the next pseudo random number
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* @return the random number
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*/
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uint32_t Randomizer::Next()
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{
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const uint32_t s = this->state[0];
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const uint32_t t = this->state[1];
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this->state[0] = s + std::rotr(t ^ 0x1234567F, 7) + 1;
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return this->state[1] = std::rotr(s, 3) - 1;
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}
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/**
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* Generate the next pseudo random number scaled to \a limit, excluding \a limit
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* itself.
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* @param limit Limit of the range to be generated from.
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* @return Random number in [0,\a limit)
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*/
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uint32_t Randomizer::Next(uint32_t limit)
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{
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return ((uint64_t)this->Next() * (uint64_t)limit) >> 32;
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}
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/**
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* (Re)set the state of the random number generator.
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* @param seed the new state
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*/
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void Randomizer::SetSeed(uint32_t seed)
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{
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this->state[0] = seed;
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this->state[1] = seed;
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}
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/**
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* (Re)set the state of the random number generators.
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* @param seed the new state
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*/
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void SetRandomSeed(uint32_t seed)
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{
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_random.SetSeed(seed);
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_interactive_random.SetSeed(seed * 0x1234567);
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}
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#ifdef RANDOM_DEBUG
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uint32_t DoRandom(int line, const char *file)
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{
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if (_networking && (!_network_server || (NetworkClientSocket::IsValidID(0) && NetworkClientSocket::Get(0)->status != NetworkClientSocket::STATUS_INACTIVE))) {
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DEBUG(random, 0, "%s; %04x; %02x; %s:%d", debug_date_dumper().HexDate(), _frame_counter, (byte)_current_company, file, line);
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}
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return _random.Next();
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}
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uint32_t DoRandomRange(uint32_t limit, int line, const char *file)
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{
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return ((uint64_t)DoRandom(line, file) * (uint64_t)limit) >> 32;
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}
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#endif /* RANDOM_DEBUG */
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