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1 #pragma once
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2 //! PRNG service. Implemented by the core, do not reimplement. Use g_create() helper function to instantiate.
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3 class NOVTABLE genrand_service : public service_base
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4 {
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5 public:
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6 void seedAuto() {seed( 0 ) ;}
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7 //! Seeds the PRNG with specified value. \n
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8 //! Default value of zero seeds automatically using available system functions.
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9 virtual void seed(unsigned val = 0) = 0;
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10 //! Returns random value N, where 0 <= N < range.
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11 virtual unsigned genrand(unsigned range)=0;
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12
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13 double genrand_f() { return (double)genrand(0xFFFFFFFF) / (double)0xFFFFFFFF; }
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14
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15 void genrand_blob( void * out, size_t bytes ) {
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16 size_t dwords = bytes/4;
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17 uint32_t * out32 = (uint32_t*) out;
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18 for(size_t w = 0; w < dwords; ++w ) {
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19 out32[w] = genrand32();
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20 }
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21 size_t left = bytes % 4;
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22 if (left > 0) {
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23 auto leftptr = (uint8_t*) out + (bytes-left);
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24 for( size_t w = 0; w < left; ++w) leftptr[w] = genrand8();
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25 }
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26 }
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27
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28 uint32_t genrand32() {
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29 return (uint32_t) genrand(0xFFFFFFFF);
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30 }
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31 uint8_t genrand8() {
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32 return (uint8_t) genrand(0x100);
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33 }
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34
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35 static service_ptr_t<genrand_service> g_create() {return standard_api_create_t<genrand_service>();}
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36
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37 void generate_random_order(t_size * out, t_size count) {
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38 unsigned genrandMax = (unsigned) pfc::min_t<size_t>(count, 0xFFFFFFFF);
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39 t_size n;
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40 for(n=0;n<count;n++) out[n]=n;
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41 for(n=0;n<count;n++) pfc::swap_t(out[n],out[genrand(genrandMax)]);
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42 }
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43
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44 FB2K_MAKE_SERVICE_COREAPI(genrand_service);
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45 };
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