BS_Praktikum4/analysis_model.h

#pragma once
#include <mutex>
#include <condition_variable>

class AnalysisModel {
    int value = 0;             
    int reader_count = 0;      
    
    std::mutex model_mutex;     
    std::mutex count_mutex;     
    std::condition_variable no_writer; 

public:
    int read() {
        std::unique_lock<std::mutex> count_lock(count_mutex);
        reader_count++;
        
        if(reader_count == 1) {
            model_mutex.lock();
        }
        count_lock.unlock();

        int result = value;

        count_lock.lock();
        reader_count--;
        if(reader_count == 0) {
            model_mutex.unlock();
            no_writer.notify_one();
        }
        
        return result;
    }

    void write(int new_value) {
        std::unique_lock<std::mutex> lock(model_mutex);
        value = new_value;
        
        no_writer.wait(lock, [this]() { 
            return reader_count == 0; 
        });
    }
};