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63 lines
1.4 KiB
C++
63 lines
1.4 KiB
C++
/*
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* RNG.h, part of VCMI engine
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*
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* Authors: listed in file AUTHORS in main folder
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*
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* License: GNU General Public License v2.0 or later
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* Full text of license available in license.txt file, in main folder
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*
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*/
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#pragma once
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VCMI_LIB_NAMESPACE_BEGIN
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namespace vstd
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{
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using TRandI64 = std::function<int64_t()>;
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using TRand = std::function<double()>;
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class DLL_LINKAGE RNG
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{
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public:
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virtual ~RNG() = default;
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virtual TRandI64 getInt64Range(int64_t lower, int64_t upper) = 0;
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virtual TRand getDoubleRange(double lower, double upper) = 0;
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};
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}
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namespace RandomGeneratorUtil
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{
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template<typename Container>
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auto nextItem(const Container & container, vstd::RNG & rand) -> decltype(std::begin(container))
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{
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assert(!container.empty());
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return std::next(container.begin(), rand.getInt64Range(0, container.size() - 1)());
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}
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template<typename Container>
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auto nextItem(Container & container, vstd::RNG & rand) -> decltype(std::begin(container))
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{
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assert(!container.empty());
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return std::next(container.begin(), rand.getInt64Range(0, container.size() - 1)());
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}
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template<typename T>
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void randomShuffle(std::vector<T> & container, vstd::RNG & rand)
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{
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int64_t n = (container.end() - container.begin());
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for(int64_t i = n-1; i>0; --i)
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{
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std::swap(container.begin()[i],container.begin()[rand.getInt64Range(0, i)()]);
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}
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}
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}
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VCMI_LIB_NAMESPACE_END
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