# random_func.cpp

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    00001 /* $Id: random_func.cpp 25893 2013-10-20 14:48:08Z fonsinchen $ */
    00002
    00003 /*
    00004  * This file is part of OpenTTD.
    00005  * 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.
    00006  * 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.
    00007  * 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/>.
    00008  */
    00009
    00012 #include "../stdafx.h"
    00013 #include "random_func.hpp"
    00014 #include "bitmath_func.hpp"
    00015
    00016 Randomizer _random, _interactive_random;
    00017
    00022 uint32 Randomizer::Next()
    00023 {
    00024   const uint32 s = this->state[0];
    00025   const uint32 t = this->state[1];
    00026
    00027   this->state[0] = s + ROR(t ^ 0x1234567F, 7) + 1;
    00028   return this->state[1] = ROR(s, 3) - 1;
    00029 }
    00030
    00037 uint32 Randomizer::Next(uint32 limit)
    00038 {
    00039   return ((uint64)this->Next() * (uint64)limit) >> 32;
    00040 }
    00041
    00046 void Randomizer::SetSeed(uint32 seed)
    00047 {
    00048   this->state[0] = seed;
    00049   this->state[1] = seed;
    00050 }
    00051
    00056 void SetRandomSeed(uint32 seed)
    00057 {
    00058   _random.SetSeed(seed);
    00059   _interactive_random.SetSeed(seed * 0x1234567);
    00060 }
    00061
    00062 #ifdef RANDOM_DEBUG
    00063 #include "../network/network.h"
    00064 #include "../network/network_server.h"
    00065 #include "../network/network_internal.h"
    00066 #include "../company_func.h"
    00067 #include "../fileio_func.h"
    00068 #include "../date_func.h"
    00069
    00070 uint32 DoRandom(int line, const char *file)
    00071 {
    00072   if (_networking && (!_network_server || (NetworkClientSocket::IsValidID(0) && NetworkClientSocket::Get(0)->status != NetworkClientSocket::STATUS_INACTIVE))) {
    00073     DEBUG(random, 0, "%08x; %02x; %04x; %02x; %s:%d", _date, _date_fract, _frame_counter, (byte)_current_company, file, line);
    00074   }
    00075
    00076   return _random.Next();
    00077 }
    00078
    00079 uint32 DoRandomRange(uint32 limit, int line, const char *file)
    00080 {
    00081   return ((uint64)DoRandom(line, file) * (uint64)limit) >> 32;
    00082 }
    00083 #endif /* RANDOM_DEBUG */