1 | /*
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2 | ** random.c - Random module
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3 | **
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4 | ** See Copyright Notice in mruby.h
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5 | */
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6 |
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7 | #include <mruby.h>
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8 | #include <mruby/variable.h>
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9 | #include <mruby/class.h>
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10 | #include <mruby/data.h>
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11 | #include <mruby/array.h>
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12 | #include <mruby/istruct.h>
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13 | #if INT32_MAX <= INTPTR_MAX
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14 | # define XORSHIFT96
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15 | # define NSEEDS 3
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16 | #else
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17 | # define NSEEDS 4
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18 | #endif
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19 | #define LASTSEED (NSEEDS-1)
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20 |
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21 | #include <time.h>
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22 |
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23 | typedef struct rand_state {
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24 | uint32_t seed[NSEEDS];
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25 | } rand_state;
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26 |
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27 | static void
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28 | rand_init(rand_state *t)
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29 | {
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30 | t->seed[0] = 123456789;
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31 | t->seed[1] = 362436069;
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32 | t->seed[2] = 521288629;
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33 | #ifndef XORSHIFT96
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34 | t->seed[3] = 88675123;
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35 | #endif
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36 | }
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37 |
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38 | static uint32_t
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39 | rand_seed(rand_state *t, uint32_t seed)
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40 | {
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41 | uint32_t old_seed = t->seed[LASTSEED];
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42 | rand_init(t);
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43 | t->seed[LASTSEED] = seed;
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44 | return old_seed;
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45 | }
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46 |
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47 | #ifdef XORSHIFT96
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48 | static uint32_t
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49 | rand_uint32(rand_state *state)
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50 | {
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51 | uint32_t *seed = state->seed;
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52 | uint32_t x = seed[0];
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53 | uint32_t y = seed[1];
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54 | uint32_t z = seed[2];
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55 | uint32_t t;
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56 |
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57 | t = (x ^ (x << 3)) ^ (y ^ (y >> 19)) ^ (z ^ (z << 6));
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58 | x = y; y = z; z = t;
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59 | seed[0] = x;
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60 | seed[1] = y;
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61 | seed[2] = z;
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62 |
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63 | return z;
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64 | }
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65 | #else /* XORSHIFT96 */
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66 | static uint32_t
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67 | rand_uint32(rand_state *state)
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68 | {
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69 | uint32_t *seed = state->seed;
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70 | uint32_t x = seed[0];
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71 | uint32_t y = seed[1];
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72 | uint32_t z = seed[2];
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73 | uint32_t w = seed[3];
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74 | uint32_t t;
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75 |
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76 | t = x ^ (x << 11);
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77 | x = y; y = z; z = w;
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78 | w = (w ^ (w >> 19)) ^ (t ^ (t >> 8));
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79 | seed[0] = x;
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80 | seed[1] = y;
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81 | seed[2] = z;
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82 | seed[3] = w;
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83 |
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84 | return w;
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85 | }
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86 | #endif /* XORSHIFT96 */
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87 |
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88 | #ifndef MRB_WITHOUT_FLOAT
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89 | static double
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90 | rand_real(rand_state *t)
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91 | {
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92 | uint32_t x = rand_uint32(t);
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93 | return x*(1.0/4294967295.0);
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94 | }
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95 | #endif
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96 |
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97 | static mrb_value
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98 | random_rand(mrb_state *mrb, rand_state *t, mrb_value max)
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99 | {
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100 | mrb_value value;
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101 |
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102 | if (mrb_fixnum(max) == 0) {
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103 | #ifndef MRB_WITHOUT_FLOAT
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104 | value = mrb_float_value(mrb, rand_real(t));
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105 | #else
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106 | mrb_raise(mrb, E_ARGUMENT_ERROR, "Float not supported");
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107 | #endif
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108 | }
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109 | else {
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110 | value = mrb_fixnum_value(rand_uint32(t) % mrb_fixnum(max));
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111 | }
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112 |
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113 | return value;
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114 | }
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115 |
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116 | static mrb_value
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117 | get_opt(mrb_state* mrb)
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118 | {
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119 | mrb_value arg;
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120 |
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121 | arg = mrb_nil_value();
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122 | mrb_get_args(mrb, "|o", &arg);
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123 |
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124 | if (!mrb_nil_p(arg)) {
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125 | mrb_int i;
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126 |
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127 | arg = mrb_to_int(mrb, arg);
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128 | i = mrb_fixnum(arg);
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129 | if (i < 0) {
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130 | arg = mrb_fixnum_value(0 - i);
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131 | }
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132 | }
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133 | return arg;
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134 | }
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135 |
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136 | static void
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137 | random_check(mrb_state *mrb, mrb_value random) {
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138 | struct RClass *c = mrb_class_get(mrb, "Random");
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139 | if (!mrb_obj_is_kind_of(mrb, random, c) || !mrb_istruct_p(random)) {
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140 | mrb_raise(mrb, E_TYPE_ERROR, "Random instance required");
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141 | }
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142 | }
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143 |
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144 | static mrb_value
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145 | random_default(mrb_state *mrb) {
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146 | struct RClass *c = mrb_class_get(mrb, "Random");
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147 | mrb_value d = mrb_const_get(mrb, mrb_obj_value(c), mrb_intern_lit(mrb, "DEFAULT"));
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148 | if (!mrb_obj_is_kind_of(mrb, d, c)) {
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149 | mrb_raise(mrb, E_TYPE_ERROR, "Random::DEFAULT replaced");
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150 | }
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151 | return d;
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152 | }
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153 |
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154 | #define random_ptr(v) (rand_state*)mrb_istruct_ptr(v)
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155 | #define random_default_state(mrb) random_ptr(random_default(mrb))
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156 |
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157 | static mrb_value
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158 | random_m_init(mrb_state *mrb, mrb_value self)
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159 | {
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160 | mrb_value seed;
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161 | rand_state *t;
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162 |
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163 | seed = get_opt(mrb);
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164 | /* avoid memory leaks */
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165 | t = random_ptr(self);
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166 | if (mrb_nil_p(seed)) {
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167 | rand_init(t);
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168 | }
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169 | else {
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170 | rand_seed(t, (uint32_t)mrb_fixnum(seed));
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171 | }
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172 |
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173 | return self;
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174 | }
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175 |
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176 | static mrb_value
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177 | random_m_rand(mrb_state *mrb, mrb_value self)
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178 | {
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179 | mrb_value max;
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180 | rand_state *t = random_ptr(self);
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181 |
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182 | max = get_opt(mrb);
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183 | return random_rand(mrb, t, max);
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184 | }
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185 |
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186 | static mrb_value
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187 | random_m_srand(mrb_state *mrb, mrb_value self)
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188 | {
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189 | uint32_t seed;
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190 | uint32_t old_seed;
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191 | mrb_value sv;
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192 | rand_state *t = random_ptr(self);
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193 |
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194 | sv = get_opt(mrb);
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195 | if (mrb_nil_p(sv)) {
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196 | seed = (uint32_t)time(NULL) + rand_uint32(t);
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197 | }
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198 | else {
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199 | seed = (uint32_t)mrb_fixnum(sv);
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200 | }
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201 | old_seed = rand_seed(t, seed);
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202 |
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203 | return mrb_fixnum_value((mrb_int)old_seed);
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204 | }
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205 |
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206 | /*
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207 | * call-seq:
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208 | * ary.shuffle! -> ary
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209 | *
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210 | * Shuffles elements in self in place.
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211 | */
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212 |
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213 | static mrb_value
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214 | mrb_ary_shuffle_bang(mrb_state *mrb, mrb_value ary)
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215 | {
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216 | mrb_int i;
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217 | mrb_value max;
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218 | mrb_value r = mrb_nil_value();
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219 | rand_state *random;
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220 |
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221 | if (RARRAY_LEN(ary) > 1) {
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222 | mrb_get_args(mrb, "|o", &r);
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223 |
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224 | if (mrb_nil_p(r)) {
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225 | random = random_default_state(mrb);
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226 | }
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227 | else {
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228 | random_check(mrb, r);
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229 | random = random_ptr(r);
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230 | }
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231 | mrb_ary_modify(mrb, mrb_ary_ptr(ary));
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232 | max = mrb_fixnum_value(RARRAY_LEN(ary));
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233 | for (i = RARRAY_LEN(ary) - 1; i > 0; i--) {
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234 | mrb_int j;
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235 | mrb_value *ptr = RARRAY_PTR(ary);
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236 | mrb_value tmp;
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237 |
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238 | j = mrb_fixnum(random_rand(mrb, random, max));
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239 |
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240 | tmp = ptr[i];
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241 | ptr[i] = ptr[j];
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242 | ptr[j] = tmp;
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243 | }
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244 | }
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245 |
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246 | return ary;
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247 | }
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248 |
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249 | /*
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250 | * call-seq:
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251 | * ary.shuffle -> new_ary
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252 | *
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253 | * Returns a new array with elements of self shuffled.
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254 | */
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255 |
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256 | static mrb_value
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257 | mrb_ary_shuffle(mrb_state *mrb, mrb_value ary)
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258 | {
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259 | mrb_value new_ary = mrb_ary_new_from_values(mrb, RARRAY_LEN(ary), RARRAY_PTR(ary));
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260 | mrb_ary_shuffle_bang(mrb, new_ary);
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261 |
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262 | return new_ary;
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263 | }
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264 |
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265 | /*
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266 | * call-seq:
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267 | * ary.sample -> obj
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268 | * ary.sample(n) -> new_ary
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269 | *
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270 | * Choose a random element or +n+ random elements from the array.
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271 | *
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272 | * The elements are chosen by using random and unique indices into the array
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273 | * in order to ensure that an element doesn't repeat itself unless the array
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274 | * already contained duplicate elements.
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275 | *
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276 | * If the array is empty the first form returns +nil+ and the second form
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277 | * returns an empty array.
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278 | */
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279 |
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280 | static mrb_value
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281 | mrb_ary_sample(mrb_state *mrb, mrb_value ary)
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282 | {
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283 | mrb_int n = 0;
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284 | mrb_bool given;
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285 | mrb_value r = mrb_nil_value();
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286 | rand_state *random;
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287 | mrb_int len;
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288 |
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289 | mrb_get_args(mrb, "|i?o", &n, &given, &r);
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290 | if (mrb_nil_p(r)) {
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291 | random = random_default_state(mrb);
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292 | }
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293 | else {
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294 | random_check(mrb, r);
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295 | random = random_ptr(r);
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296 | }
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297 | len = RARRAY_LEN(ary);
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298 | if (!given) { /* pick one element */
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299 | switch (len) {
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300 | case 0:
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301 | return mrb_nil_value();
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302 | case 1:
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303 | return RARRAY_PTR(ary)[0];
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304 | default:
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305 | return RARRAY_PTR(ary)[rand_uint32(random) % len];
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306 | }
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307 | }
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308 | else {
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309 | mrb_value result;
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310 | mrb_int i, j;
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311 |
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312 | if (n < 0) mrb_raise(mrb, E_ARGUMENT_ERROR, "negative sample number");
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313 | if (n > len) n = len;
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314 | result = mrb_ary_new_capa(mrb, n);
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315 | for (i=0; i<n; i++) {
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316 | mrb_int r;
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317 |
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318 | for (;;) {
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319 | retry:
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320 | r = (mrb_int)(rand_uint32(random) % len);
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321 |
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322 | for (j=0; j<i; j++) {
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323 | if (mrb_fixnum(RARRAY_PTR(result)[j]) == r) {
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324 | goto retry; /* retry if duplicate */
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325 | }
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326 | }
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327 | break;
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328 | }
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329 | mrb_ary_push(mrb, result, mrb_fixnum_value(r));
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330 | }
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331 | for (i=0; i<n; i++) {
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332 | mrb_ary_set(mrb, result, i, RARRAY_PTR(ary)[mrb_fixnum(RARRAY_PTR(result)[i])]);
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333 | }
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334 | return result;
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335 | }
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336 | }
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337 |
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338 | static mrb_value
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339 | random_f_rand(mrb_state *mrb, mrb_value self)
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340 | {
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341 | rand_state *t = random_default_state(mrb);
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342 | return random_rand(mrb, t, get_opt(mrb));
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343 | }
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344 |
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345 | static mrb_value
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346 | random_f_srand(mrb_state *mrb, mrb_value self)
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347 | {
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348 | mrb_value random = random_default(mrb);
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349 | return random_m_srand(mrb, random);
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350 | }
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351 |
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352 |
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353 | void mrb_mruby_random_gem_init(mrb_state *mrb)
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354 | {
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355 | struct RClass *random;
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356 | struct RClass *array = mrb->array_class;
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357 |
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358 | mrb_assert(sizeof(rand_state) <= ISTRUCT_DATA_SIZE);
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359 |
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360 | mrb_define_method(mrb, mrb->kernel_module, "rand", random_f_rand, MRB_ARGS_OPT(1));
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361 | mrb_define_method(mrb, mrb->kernel_module, "srand", random_f_srand, MRB_ARGS_OPT(1));
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362 |
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363 | random = mrb_define_class(mrb, "Random", mrb->object_class);
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364 | MRB_SET_INSTANCE_TT(random, MRB_TT_ISTRUCT);
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365 | mrb_define_class_method(mrb, random, "rand", random_f_rand, MRB_ARGS_OPT(1));
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366 | mrb_define_class_method(mrb, random, "srand", random_f_srand, MRB_ARGS_OPT(1));
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367 |
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368 | mrb_define_method(mrb, random, "initialize", random_m_init, MRB_ARGS_OPT(1));
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369 | mrb_define_method(mrb, random, "rand", random_m_rand, MRB_ARGS_OPT(1));
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370 | mrb_define_method(mrb, random, "srand", random_m_srand, MRB_ARGS_OPT(1));
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371 |
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372 | mrb_define_method(mrb, array, "shuffle", mrb_ary_shuffle, MRB_ARGS_OPT(1));
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373 | mrb_define_method(mrb, array, "shuffle!", mrb_ary_shuffle_bang, MRB_ARGS_OPT(1));
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374 | mrb_define_method(mrb, array, "sample", mrb_ary_sample, MRB_ARGS_OPT(2));
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375 |
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376 | mrb_const_set(mrb, mrb_obj_value(random), mrb_intern_lit(mrb, "DEFAULT"),
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377 | mrb_obj_new(mrb, random, 0, NULL));
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378 | }
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379 |
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380 | void mrb_mruby_random_gem_final(mrb_state *mrb)
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381 | {
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382 | }
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