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1 /* $Id$ */ |
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2 |
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3 /** @file random_func.cpp */ |
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4 |
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5 #include "../stdafx.h" |
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6 #include "../macros.h" |
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7 #include "../variables.h" |
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8 #include "random_func.hpp" |
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9 |
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10 uint32 InteractiveRandom() |
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11 { |
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12 const uint32 s = _random_seeds[1][0]; |
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13 const uint32 t = _random_seeds[1][1]; |
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14 |
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15 _random_seeds[1][0] = s + ROR(t ^ 0x1234567F, 7) + 1; |
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16 return _random_seeds[1][1] = ROR(s, 3) - 1; |
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17 } |
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18 |
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19 uint InteractiveRandomRange(uint max) |
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20 { |
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21 return GB(InteractiveRandom(), 0, 16) * max >> 16; |
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22 } |
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23 |
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24 #ifdef MERSENNE_TWISTER |
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25 // Source code for Mersenne Twister. |
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26 // A Random number generator with much higher quality random numbers. |
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27 |
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28 #define N (624) // length of _mt_state vector |
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29 #define M (397) // a period parameter |
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30 #define K (0x9908B0DFU) // a magic constant |
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31 #define hiBit(u) ((u) & 0x80000000U) // mask all but highest bit of u |
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32 #define loBit(u) ((u) & 0x00000001U) // mask all but lowest bit of u |
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33 #define loBits(u) ((u) & 0x7FFFFFFFU) // mask the highest bit of u |
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34 #define mixBits(u, v) (hiBit(u)|loBits(v)) // move hi bit of u to hi bit of v |
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35 |
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36 static uint32 _mt_state[N+1]; // _mt_state vector + 1 extra to not violate ANSI C |
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37 static uint32 *_mt_next; // _mt_next random value is computed from here |
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38 static int _mt_left = -1; // can *_mt_next++ this many times before reloading |
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39 |
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40 void SetRandomSeed(register uint32 seed) |
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41 { |
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42 register uint32 *s = _mt_state; |
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43 _mt_left = 0; |
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44 |
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45 seed |= 1U; |
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46 seed &= 0xFFFFFFFFU; |
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47 |
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48 *s = seed; |
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49 |
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50 for (register uint i = N; i != 0; i--) { |
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51 seed *= 69069U; |
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52 *s++; |
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53 *s = seed & 0xFFFFFFFFU; |
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54 } |
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55 } |
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56 |
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57 static uint32 ReloadRandom() |
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58 { |
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59 if (_mt_left < -1) SetRandomSeed(4357U); |
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60 |
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61 _mt_left = N - 1; |
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62 _mt_next = _mt_state + 1; |
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63 |
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64 register uint32 *p0 = _mt_state; |
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65 register uint32 *p2 = _mt_state + 2; |
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66 register uint32 *pM = _mt_state + M; |
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67 |
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68 register uint32 s0 = _mt_state[0]; |
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69 register uint32 s1 = _mt_state[1]; |
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70 |
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71 register uint i = 0; |
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72 |
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73 for (i = (N - M + 1); i != 0; i--) { |
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74 s0 = s1; |
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75 s1 = *p2; |
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76 *p0 = *pM ^ (mixBits(s0, s1) >> 1) ^ (loBit(s1) ? K : 0U); |
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77 *p0++; |
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78 *p2++; |
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79 *pM++; |
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80 } |
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81 |
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82 pM = _mt_state; |
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83 |
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84 for (i = M; i != 0; i--) { |
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85 s0 = s1; |
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86 s1 = *p2; |
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87 *p0 = *pM ^ (mixBits(s0, s1) >> 1) ^ (loBit(s1) ? K : 0U); |
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88 *p0++; |
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89 *p2++; |
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90 *pM++; |
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91 } |
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92 |
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93 s1 = _mt_state[0]; |
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94 *p0 = *pM ^ (mixBits(s0, s1) >> 1) ^ (loBit(s1) ? K : 0U); |
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95 |
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96 s1 ^= (s1 >> 11); |
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97 s1 ^= (s1 << 7) & 0x9D2C5680U; |
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98 s1 ^= (s1 << 15) & 0xEFC60000U; |
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99 s1 ^= (s1 >> 18); |
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100 return s1; |
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101 } |
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102 |
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103 uint32 Random() |
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104 { |
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105 _mt_left--; |
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106 if (_mt_left < 0) return ReloadRandom(); |
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107 |
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108 uint32 y = *_mt_next; |
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109 *_mt_next++; |
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110 |
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111 y ^= (y >> 11); |
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112 y ^= (y << 7) & 0x9D2C5680U; |
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113 y ^= (y << 15) & 0xEFC60000U; |
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114 y ^= (y >> 18); |
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115 return y; |
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116 } |
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117 |
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118 #else /* MERSENNE_TWISTER */ |
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119 void SetRandomSeed(uint32 seed) |
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120 { |
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121 _random_seeds[0][0] = seed; |
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122 _random_seeds[0][1] = seed; |
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123 _random_seeds[1][0] = seed * 0x1234567; |
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124 _random_seeds[1][1] = _random_seeds[1][0]; |
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125 } |
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126 |
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127 #ifdef RANDOM_DEBUG |
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128 #include "network/network_data.h" |
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129 uint32 DoRandom(int line, const char *file) |
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130 { |
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131 if (_networking && (DEREF_CLIENT(0)->status != STATUS_INACTIVE || !_network_server)) |
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132 printf("Random [%d/%d] %s:%d\n",_frame_counter, (byte)_current_player, file, line); |
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133 #else /* RANDOM_DEBUG */ |
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134 uint32 Random() |
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135 { |
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136 #endif /* RANDOM_DEBUG */ |
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137 const uint32 s = _random_seeds[0][0]; |
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138 const uint32 t = _random_seeds[0][1]; |
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139 |
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140 _random_seeds[0][0] = s + ROR(t ^ 0x1234567F, 7) + 1; |
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141 return _random_seeds[0][1] = ROR(s, 3) - 1; |
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142 } |
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143 #endif /* MERSENNE_TWISTER */ |
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144 |
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145 #if defined(RANDOM_DEBUG) && !defined(MERSENNE_TWISTER) |
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146 uint DoRandomRange(uint max, int line, const char *file) |
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147 { |
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148 return GB(DoRandom(line, file), 0, 16) * max >> 16; |
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149 } |
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150 #else /* RANDOM_DEBUG & !MERSENNE_TWISTER */ |
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151 uint RandomRange(uint max) |
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152 { |
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153 return GB(Random(), 0, 16) * max >> 16; |
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154 } |
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155 #endif /* RANDOM_DEBUG & !MERSENNE_TWISTER */ |