RequestGenerator.h

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#ifndef REQUESTGENERATOR_H
#define REQUESTGENERATOR_H
 
#include <array>
#include <cstdint>
#include <random>
#include <string>
#include <vector>
 
#include "Request.h"

struct GeneratorSettings {
    unsigned int minTaskCycles = 10;   
    unsigned int maxTaskCycles = 100;  
    double arrivalRate = 0.45;         
    double waveAmplitude = 0.6;        
    unsigned long wavePeriod = 25000;  
    double streamingShare = 0.35;      
};

struct GeneratorStats {
    static constexpr std::size_t kTaskBins = 10;    
    static constexpr std::size_t kArrivalBins = 5;  
 
    unsigned long total = 0;           
    unsigned long initial = 0;         
    unsigned long processing = 0;      
    unsigned long streaming = 0;       
    unsigned int minTaskSeen = 0;      
    unsigned int maxTaskSeen = 0;      
    unsigned long long taskCycleSum = 0; 
    std::array<unsigned long, kTaskBins> taskHistogram{};       
    std::array<unsigned long, kArrivalBins> arrivalHistogram{}; 
    unsigned long maxArrivalsInCycle = 0; 
};

class RequestGenerator {
public:
    RequestGenerator(const GeneratorSettings& settings, std::uint32_t seed);

    Request makeRequest(unsigned long cycle);

    std::vector<Request> makeInitialBatch(std::size_t count, unsigned long cycle);

    std::vector<Request> arrivalsFor(unsigned long cycle);

    double rateAt(unsigned long cycle) const;

    const GeneratorSettings& settings() const;

    const GeneratorStats& stats() const;

    std::uint32_t seed() const;

    const std::vector<Request>& samples() const;
 
private:
    std::string randomIp();
    void record(const Request& request);
 
    GeneratorSettings settings_;
    std::uint32_t seed_;
    std::mt19937 engine_;
    std::uniform_int_distribution<unsigned int> taskCycles_;
    std::uniform_int_distribution<unsigned int> octet_;
    std::uniform_int_distribution<unsigned int> firstOctet_;
    std::uniform_int_distribution<unsigned int> hostOctet_;
    std::bernoulli_distribution streaming_;
    std::poisson_distribution<unsigned int> arrivals_;  
    GeneratorStats stats_;
    std::vector<Request> samples_;
    unsigned long nextId_ = 1;
};
 
#endif