# random_func.hpp

Go to the documentation of this file.

    00001 /* $Id: random_func.hpp 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 #ifndef RANDOM_FUNC_HPP
    00013 #define RANDOM_FUNC_HPP
    00014
    00015 #if defined(__APPLE__)
    00016   /* Apple already has Random declared */
    00017   #define Random OTTD_Random
    00018 #endif /* __APPLE__ */
    00019
    00023 struct Randomizer {
    00025   uint32 state[2];
    00026
    00027   uint32 Next();
    00028   uint32 Next(uint32 limit);
    00029   void SetSeed(uint32 seed);
    00030 };
    00031 extern Randomizer _random;
    00032 extern Randomizer _interactive_random;
    00033
    00035 struct SavedRandomSeeds {
    00036   Randomizer random;
    00037   Randomizer interactive_random;
    00038 };
    00039
    00044 static inline void SaveRandomSeeds(SavedRandomSeeds *storage)
    00045 {
    00046   storage->random = _random;
    00047   storage->interactive_random = _interactive_random;
    00048 }
    00049
    00054 static inline void RestoreRandomSeeds(const SavedRandomSeeds &storage)
    00055 {
    00056   _random = storage.random;
    00057   _interactive_random = storage.interactive_random;
    00058 }
    00059
    00060 void SetRandomSeed(uint32 seed);
    00061 #ifdef RANDOM_DEBUG
    00062   #ifdef __APPLE__
    00063     #define OTTD_Random() DoRandom(__LINE__, __FILE__)
    00064   #else
    00065     #define Random() DoRandom(__LINE__, __FILE__)
    00066   #endif
    00067   uint32 DoRandom(int line, const char *file);
    00068   #define RandomRange(limit) DoRandomRange(limit, __LINE__, __FILE__)
    00069   uint32 DoRandomRange(uint32 limit, int line, const char *file);
    00070 #else
    00071   static inline uint32 Random()
    00072   {
    00073     return _random.Next();
    00074   }
    00075
    00083   static inline uint32 RandomRange(uint32 limit)
    00084   {
    00085     return _random.Next(limit);
    00086   }
    00087 #endif
    00088
    00089 static inline uint32 InteractiveRandom()
    00090 {
    00091   return _interactive_random.Next();
    00092 }
    00093
    00094 static inline uint32 InteractiveRandomRange(uint32 limit)
    00095 {
    00096   return _interactive_random.Next(limit);
    00097 }
    00098
    00114 static inline bool Chance16I(const uint a, const uint b, const uint32 r)
    00115 {
    00116   assert(b != 0);
    00117   return (((uint16)r * b + b / 2) >> 16) < a;
    00118 }
    00119
    00130 #ifdef RANDOM_DEBUG
    00131   #define Chance16(a, b) Chance16I(a, b, DoRandom(__LINE__, __FILE__))
    00132 #else
    00133 static inline bool Chance16(const uint a, const uint b)
    00134 {
    00135   return Chance16I(a, b, Random());
    00136 }
    00137 #endif /* RANDOM_DEBUG */
    00138
    00154 #ifdef RANDOM_DEBUG
    00155   #define Chance16R(a, b, r) (r = DoRandom(__LINE__, __FILE__), Chance16I(a, b, r))
    00156 #else
    00157 static inline bool Chance16R(const uint a, const uint b, uint32 &r)
    00158 {
    00159   r = Random();
    00160   return Chance16I(a, b, r);
    00161 }
    00162 #endif /* RANDOM_DEBUG */
    00163
    00164 #endif /* RANDOM_FUNC_HPP */