main.cpp

#include <iostream>
#include <fstream>
#include <vector>
#include <sstream>
#include <string>
#include <cstring>

using namespace std;

struct Record {
    int id;
    string name;
    string bio;
    int managerId;
};

void parseCSV(const string& line, Record& record) {
    stringstream ss(line);
    string token;

    getline(ss, token, ',');
    record.id = stoi(token);

    getline(ss, record.name, ',');
    getline(ss, record.bio, ',');

    getline(ss, token, ',');
    record.managerId = stoi(token);
}

void writeRecord(ofstream& outfile, const Record& record) {
    // Calculate sizes of data elements
    int idSize = sizeof(record.id);
    /*cout << "record.id = " << record.id << endl;
    cout << "idSize = " << idSize << endl;*/
    int nameSize = record.name.size();
/*     cout << "record.name = " << record.name << endl;
    cout << "nameSize = " << nameSize << endl; */
    int bioSize = record.bio.size();
/*     cout << "record.bio = " << record.bio << endl;
    cout << "bioSize = " << bioSize << endl; */
    int managerIdSize = sizeof(record.managerId);
 /*    cout << "record.managerId = " << record.managerId << endl;
    cout << "managerIdSize = " << managerIdSize << endl; */


    // Calculate offsets
    int idOffset = sizeof(int) * 4; // 4 integers before the id
    int nameOffset = idOffset + idSize;
    int bioOffset = nameOffset + nameSize;
    int managerIdOffset = bioOffset + bioSize;

    // Write offsets as strings
    outfile << idOffset;
    outfile << nameOffset;
    outfile << bioOffset;
    outfile << managerIdOffset;

    // Write data as strings
    outfile << record.id;
    outfile << record.name;
    outfile << record.bio;
    outfile << record.managerId;
}

int main() {
    const string fileName = "EmployeeRelation.txt";
    const string inputFile = "Employee.csv";
    const int pageSize = 4096; // Page size

    // Create the EmployeeRelation file from Employee.csv
    ofstream outfile(fileName, ios::binary);
    ifstream infile(inputFile);

    if (!infile || !outfile) {
        cerr << "Error opening files." << endl;
        return 1;
    }

    int currentPageSize = sizeof(int) * 2; // Current page size
    vector<int> slotDirectory; // Slot directory for the current page
    int freeSpacePointer = 0; // Pointer to the start of free space on the current page
    int pages = 0; // Track # of previous "pages"
    
    string line;
    while (getline(infile, line)) {
        Record record;
        parseCSV(line, record);
        
        // Calculate the size of the record
        int idSize = sizeof(record.id);
        int nameSize = record.name.size();
        int bioSize = record.bio.size();
        int managerIdSize = sizeof(record.managerId);
        int recordSize = idSize + nameSize + bioSize + managerIdSize + sizeof(int) * 4; // Include sizes of data elements and offsets

        // Check if adding the record will exceed the page size
        if (currentPageSize + recordSize > pageSize) {
            int directorySize = slotDirectory.size();
            // Find where to write the directory
            outfile.seekp(4096 * (pages + 1) - (directorySize*sizeof(int) + 2*sizeof(int)));   // Write slot directory to the file
            for (int& size : slotDirectory) {
                outfile << size;
                
            }
            outfile << directorySize; // Write the size of the slot directory
            outfile << freeSpacePointer; // Write the free space pointer

            // Reset slot directory and free space pointer for the new page
            slotDirectory.clear();
            pages += 1;
            freeSpacePointer = pages * 4096;
            currentPageSize = sizeof(int) * 2;
        }
        
        // Write the record to the file
        outfile.seekp(freeSpacePointer);
        writeRecord(outfile, record);

        
        // Update slot directory and free space pointer
        slotDirectory.push_back(recordSize);
        
        freeSpacePointer += recordSize;
        // Update current page size
        currentPageSize += recordSize + sizeof(int);
    }

    infile.close();
    outfile.close();

    return 0;
}