OS-Labs/lab3/scheduler.cpp

#include <iostream>
#include <fstream>
#include <cstring>
#include <unistd.h>
#include <chrono>
#include <sstream>
#include <string>
#include <bits/stdc++.h>

using namespace std;

struct process_detail {
	//cpu_burst_times[0] is arrival time
	int pid;
	vector<int> burst_times;
	int in_cpu;
	int current_burst_index;
};

struct clock{
	int push_signal; //boolean
	int timer;

};

//// operator overloading
//struct CompareHeight {
//    bool operator()(struct process_detail p1, struct process_detail p2)
//    {
//        // return "true" if "p1" is ordered
//        // before "p2", for example:
//        return p1.height < p2.height;
//    }
//};


vector<process_detail> processes;
queue<process_detail*> ready_queue_fifo;
vector<process_detail*> waiting;
struct process_detail* CPU = NULL;

ofstream output_file("cpu_times.txt");

void fifo() {

	//clock initialized to 0
	struct clock time;
	memset(&time, 0, sizeof(struct clock));
	time.timer = 0;
	time.push_signal = 0;
	int process_count = processes.size();
	int completed_processes = 0;

	while(completed_processes < process_count){

		// breaking from the infinite loop
		for(int i = 0; i < process_count; ++i) {
			if(processes[i].burst_times[processes[i].current_burst_index] == -1) {
				completed_processes++;
			}
		}

		//managing arrival times
		for(int i = 0; i < process_count; ++i) {
			//if process not in cpu
			if(processes[i].in_cpu != 1) {
				if(time.timer == processes[i].burst_times[0]) {
					ready_queue_fifo.push(&processes[i]);
					processes[i].current_burst_index++;
				}
			}
		}

		//THE FIFO RULE
		if(CPU == NULL && !ready_queue_fifo.empty()) {
			CPU = ready_queue_fifo.front();
			CPU->in_cpu = 1;
			// Record in_time when the process enters the CPU
			CPU->burst_times[CPU->current_burst_index]--;
            output_file << "P" << CPU->pid+1 << " " << time.timer;
			ready_queue_fifo.pop();

		}
		// else if(CPU == NULL && ready_queue_fifo.empty()) {
		// 	// removing form waiting list
		// 	for(int j = 0; j < waiting.size(); ++j) {
		// 		if(waiting[j] != NULL) {
		// 			if(waiting[j]->burst_times[waiting[j]->current_burst_index] == 0) {
		// 				ready_queue_fifo.push(waiting[j]);
		// 				waiting[j]->current_burst_index++;
		// 				waiting[j] = NULL;
		// 			}
		// 			else waiting[j]->burst_times[waiting[j]->current_burst_index]--; // reducing the io burst till it reaches 0
		// 		}

		// 	}
		// 	time.push_signal++;
		// }
		else {
			// removing form waiting list
			for(int j = 0; j < waiting.size(); ++j) {
				if(waiting[j] != NULL) {
					if(waiting[j]->burst_times[waiting[j]->current_burst_index] == 0) {
						ready_queue_fifo.push(waiting[j]);
						waiting[j]->current_burst_index++;
						waiting[j] = NULL;
					}
					else waiting[j]->burst_times[waiting[j]->current_burst_index]--; // reducing the io burst till it reaches 0
				}

			}
			//check cpu_burst complete
			for(int i = 0; i < process_count; ++i) {
				if(processes[i].in_cpu == 1 && CPU != NULL) {
					if(CPU->burst_times[processes[i].current_burst_index] == 0){
						// Record out_time when the process exits the CPU
                        output_file << " " << time.timer << endl;
						// time.push_signal = time.push_signal + CPU->burst_times[processes[i].current_burst_index] ;
						CPU->in_cpu = 0;
						CPU->current_burst_index++;
						// CPU->burst_times[CPU->current_burst_index]--;
						waiting.push_back(CPU); // process added to waiting queue
						if(!ready_queue_fifo.empty()) {
							CPU = ready_queue_fifo.front(); // process added to CPU
							CPU->in_cpu = 1;
							// CPU->burst_times[CPU->current_burst_index]--;
							output_file << "P" << CPU->pid+1 << " " << time.timer; // New entry time
							ready_queue_fifo.pop();
						}
						else {
							CPU = NULL;
						}
					}
					else CPU->burst_times[CPU->current_burst_index]--;
				}
			}

		}
		time.timer++;
		// completed_processes++;
	}
	output_file.close();
	cout << "fifo" << endl;
	return;
}

int main(int argc, char **argv) {

    if(argc != 3)
	{
		cout <<"usage: ./scheduler.out <path-to-workload-file> <scheduler_algorithm>\nprovided arguments:\n";
		for(int i = 0; i < argc; i++)
			cout << argv[i] << "\n";
		return -1;
	}

    char *file_to_search_in = argv[1];
	char *scheduler_algorithm = argv[2];

    ifstream file(file_to_search_in, ios::binary);
    // ifstream file("process1.dat", ios::binary);
    string buffer;
    int pid = 0;

    while(getline(file, buffer)) {
		if(buffer[0] == '<'){
			continue;
		}
		istringstream iss(buffer);
		string word;
		struct process_detail pd;
		memset(&pd,0,sizeof(struct process_detail));
		pd.pid = pid++;
		pd.current_burst_index = 0;

		while(iss>>word){
//			if(i == 0){
//				pd.cpu_burst_times.push_back(stoi(word));
//			}
//			else if(i % 2 == 0){
//				pd.io_burst_times.push_back(stoi(word));
//			}
//			else if(i % 2 == 1){
//			}
			pd.burst_times.push_back(stoi(word));
//			i++;
//			cout << stoi(word) << endl;
		}
		processes.push_back(pd);
    }

	map<string, int> temp;
	temp["fifo"] = 1;
	string temp1 = scheduler_algorithm;
	// string temp1 = "fifo";


	switch(temp[temp1]){
		case 1:
			fifo();
			break;
		default:
			cout << "enter fifo" << endl;
	}

	// cout << processes[0].in_cpu << endl;
	// cout << processes[0].current_burst_index << endl;

	// cout << processes[1].in_cpu << endl;
	// cout << processes[1].current_burst_index << endl;

	// cout << ready_queue_fifo.front()->pid << endl;
	// ready_queue_fifo.pop();
	// cout << ready_queue_fifo.front()->pid << endl;

    return 0;
}