/* Pseudocode of the barbershop problem
 * William Stallings, "Operating Systems Internals and Design Principles," 
 * 6/e, Prentice Hall, 2009, p. 763
 */

semaphore max_capacity = 20;
semaphore sofa = 4,  barber_chair = 3, coord = 3;
semaphore cust_ready = 0, leave_b_chair = 0, payment= 0, receipt = 0;
semaphore finished[50] = {0};
semaphore mutex1 = 1, mutex2 = 1;
int count;

void customer()
{ 
    int cust_nr;
    
    wait(max_capacity);
    enter_shop();
    wait(mutex1);
    cust_nr = count;
    count++;
    signal(mutex1);
    wait(sofa);
    sit_on_sofa();
    wait(barber_chair);
    get_up_from_sofa();
    signal(sofa);
    sit_in_barber_chair();
    wait(mutex2);
    enqueue1(cust_nr)
    signal(mutex2);
    signal(cust_ready);
    wait(finished[cust_nr]);
    leave_barber_chair();
    signal(leave_b_chair);
    pay();
    signal(payment);
    wait(receipt);
    exit_shop();
    signal(max_capacity);
}


void barber()
{
    int b_cust;
    
    while (true)
    {
        wait(cust_ready);
        wait(mutex2);
        dequeue1(b_cust);
        signal(mutex2);
        wait(coord);
        cut_hair();
        signal(coord);
        signal(finished[b_cust]);
        wait(leave_b_chair);
        signal(barber_chair);
    }
}

void cashier()
{
    while (true)
    { 
        wait(payment);
        wait(coord);
        accept_pay();
        signal(coord);
        signal(receipt);
    }
}