FuzzingUtils.h
63 lines
| 2.3 KiB
| text/x-c
|
CLexer
Alexandre Leroux
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r1206 | #ifndef SCIQLOP_FUZZINGUTILS_H | ||
| #define SCIQLOP_FUZZINGUTILS_H | ||||
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r1215 | #include <algorithm> | ||
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r1206 | #include <random> | ||
| /** | ||||
| * Class that proposes random utility methods | ||||
| */ | ||||
| class RandomGenerator { | ||||
| public: | ||||
| /// @return the unique instance of the random generator | ||||
| static RandomGenerator &instance(); | ||||
| /// Generates a random double between [min, max] | ||||
| double generateDouble(double min, double max); | ||||
| /// Generates a random int between [min, max] | ||||
| int generateInt(int min, int max); | ||||
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Alexandre Leroux
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r1215 | /** | ||
| * Returns a random element among the elements of a container. An item may be more likely to be | ||||
| * selected if it has an associated weight greater than other items | ||||
| * @param container the container from which to retrieve an element | ||||
| * @param weights the weight associated to each element of the container. The vector must have | ||||
| * the same size of the container for the weights to be effective | ||||
| * @param nbDraws the number of random draws to perform | ||||
| * @return the random element retrieved, an element built by default if the container is empty | ||||
| */ | ||||
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Alexandre Leroux
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r1206 | template <typename T, typename ValueType = typename T::value_type> | ||
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r1215 | ValueType randomChoice(const T &container, const std::vector<double> &weights = {}); | ||
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r1206 | |||
| private: | ||||
| std::mt19937 m_Mt; | ||||
| explicit RandomGenerator(); | ||||
| }; | ||||
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r1211 | template <typename T, typename ValueType> | ||
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r1215 | ValueType RandomGenerator::randomChoice(const T &container, const std::vector<double> &weights) | ||
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r1206 | { | ||
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r1211 | if (container.empty()) { | ||
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r1206 | return ValueType{}; | ||
| } | ||||
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r1215 | // Generates weights for each element: if the weights passed in parameter are malformed (the | ||
| // number of weights defined is inconsistent with the number of elements in the container, or | ||||
| // all weights are zero), default weights are used | ||||
| auto nbIndexes = container.size(); | ||||
| std::vector<double> indexWeights(nbIndexes); | ||||
| if (weights.size() != nbIndexes || std::all_of(weights.cbegin(), weights.cend(), | ||||
| [](const auto &val) { return val == 0.; })) { | ||||
| std::fill(indexWeights.begin(), indexWeights.end(), 1.); | ||||
| } | ||||
| else { | ||||
| std::copy(weights.begin(), weights.end(), indexWeights.begin()); | ||||
| } | ||||
| // Performs a draw to determine the index to return | ||||
| std::discrete_distribution<> d{indexWeights.cbegin(), indexWeights.cend()}; | ||||
| return container.at(d(m_Mt)); | ||||
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Alexandre Leroux
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r1206 | } | ||
| #endif // SCIQLOP_FUZZINGUTILS | ||||