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#include "random_provider.h" 
#include <util/random/mersenne.h> 
#include <util/random/random.h> 
#include <util/system/unaligned_mem.h>
 
namespace { 
    void SetV4(TGUID& g) { 
        g.dw[1] &= 0x0fffffff; 
        g.dw[1] |= 0x40000000; 
 
        g.dw[2] &= 0xffffff3f; 
        g.dw[2] |= 0x00000080; 
    } 
} 
 
class TDefaultRandomProvider: public IRandomProvider { 
public: 
    ui64 GenRand() noexcept override { 
        return RandomNumber<ui64>(); 
    } 
 
    TGUID GenGuid() noexcept override { 
        TGUID ret; 
        CreateGuid(&ret); 
        return ret; 
    } 
 
    TGUID GenUuid4() noexcept override {
        TGUID ret; 
        WriteUnaligned<ui64>(ret.dw, RandomNumber<ui64>());
        WriteUnaligned<ui64>(ret.dw + 2, RandomNumber<ui64>());
        SetV4(ret); 
        return ret; 
    } 
}; 
 
class TDeterministicRandomProvider: public IRandomProvider { 
public: 
    TDeterministicRandomProvider(ui64 seed) 
        : Gen(seed) 
    { 
    } 
 
    ui64 GenRand() noexcept override { 
        return Gen.GenRand(); 
    } 
 
    TGUID GenGuid() noexcept override { 
        TGUID ret; 
        WriteUnaligned<ui64>(ret.dw, Gen.GenRand());
        ret.dw[2] = (ui32)Gen.GenRand(); 
        ret.dw[3] = ++GuidCount; 
        return ret; 
    } 
 
    TGUID GenUuid4() noexcept override {
        TGUID ret; 
        WriteUnaligned<ui64>(ret.dw, Gen.GenRand());
        WriteUnaligned<ui64>(ret.dw + 2, Gen.GenRand());
        SetV4(ret); 
        return ret; 
    } 
 
private: 
    TMersenne<ui64> Gen; 
    ui32 GuidCount = 0; 
}; 
 
TIntrusivePtr<IRandomProvider> CreateDefaultRandomProvider() { 
    return TIntrusivePtr<IRandomProvider>(new TDefaultRandomProvider()); 
} 
 
TIntrusivePtr<IRandomProvider> CreateDeterministicRandomProvider(ui64 seed) { 
    return TIntrusivePtr<IRandomProvider>(new TDeterministicRandomProvider(seed)); 
}