60 lines
1.4 KiB
C++
60 lines
1.4 KiB
C++
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// FastRandom.cpp
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#include "Globals.h"
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#include "FastRandom.h"
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#if defined (__GNUC__)
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#define ATTRIBUTE_TLS static __thread
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#elif defined (_MSC_VER)
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#define ATTRIBUTE_TLS static __declspec(thread)
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#else
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#define ATTRIBUTE_TLS thread_local
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#endif
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MTRand & GetRandomProvider()
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{
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// Some compilers don't support thread_local for non-POD types, this is purely a work around for that restriction.
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// There should be minimal overhead for the non-initializing case and all thread's instances are deleted properly.
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ATTRIBUTE_TLS MTRand * LocalPtr = nullptr;
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if (LocalPtr == nullptr)
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{
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// This list allows deletion of elements as if they had static storage duration
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static std::mutex CSDeleteList;
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static std::list<std::unique_ptr<MTRand>> DeleteList;
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cRandomDeviceSeeder seeder;
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auto NewInstance = cpp14::make_unique<MTRand>(seeder);
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auto TempPtr = NewInstance.get();
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std::lock_guard<std::mutex> Lock(CSDeleteList);
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DeleteList.push_front(std::move(NewInstance));
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LocalPtr = TempPtr; // Set after push_back so LocalPtr won't dangle if it throws
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}
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return *LocalPtr;
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}
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UInt32 Detail::GetRandomSeed()
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{
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ATTRIBUTE_TLS bool SeedCounterInitialized = false;
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ATTRIBUTE_TLS UInt32 SeedCounter = 0;
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if (!SeedCounterInitialized)
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{
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std::random_device rd;
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std::uniform_int_distribution<UInt32> dist;
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SeedCounter = dist(rd);
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SeedCounterInitialized = true;
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}
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return ++SeedCounter;
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}
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