Initial commit

DiningPhilosophers.c

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+#include <pthread.h>
+#include <semaphore.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <stdbool.h>
+
+#define N           5           /*number of philosophers*/
+#define LEFT        (i+N-1)%N   /*number of i's left neighbor*/
+#define RIGHT       (i+1)%N     /*number of i's right neighbor*/
+#define THINKING    0           /*philosopher is thinking*/
+#define HUNGRY      1           /*philosopher is trying to get forks*/
+#define EATING      2           /*philosopher is eating*/
+int philosopherState[N];                   /*array to keep track of everyone's state*/
+sem_t mutex = 1;            /*mutual exclusion for critical region*/
+sem_t philosopherSemaphore[N];                 /*one semaphore per philospher*/
+
+void Down(sem_t* selectedSemaphore);
+void Eat(int selectedPhilosopher);
+int GetNumberPhilosophers(char* argv);
+void Philosopher(int selectedPhilosopher);
+void PutForks(int selectedPhilosopher);
+void TakeForks(int selectedPhilosopher);
+void Test(int selectedPhilosopher);
+void Think(int selectedPhilosopher);
+void Up(sem_t* selectedSemaphore);
+
+/*
+ *  Todo:
+ *      Create function up()
+ *      Create function down()
+ *      Create function eat()
+ *      Create function think()
+ *      Add prints to each state change
+ *  Theories:
+ *      Threads should be put to sleep if can't eat
+ *      Sleep has to be awoken by something else, process can't wake own thread
+ *      Place semaphores so states can be checked by all
+ *      Total fork count = N / 2
+ *
+ */
+
+int main(int argc, char* argv[]) 
+{
+    if (argc == 2)
+    {
+        int philosopherCount;
+        philosopherCount = GetNumberPhilosophers(argv[1]);
+        Philosopher(philosopherCount);
+    }
+    return 0;
+}
+
+//
+//  TODO:
+//      Turn function into putting down forks (releasing waits)
+//
+void Down(sem_t* selectedSemaphore)
+{
+    printf("Function Down() was called.\n");
+}
+
+// 
+//  TODO: 
+//      Add changing state to function
+//      Add increasing eating count functionality
+//
+void Eat(int selectedPhilosopher)
+{
+    printf("Function Eat() was called.\n");
+}
+
+// Takes in char* and converts into a number
+// Returns a number
+int GetNumberPhilosophers(char* argv)
+{
+    int numPhilosophers;
+    sscanf(argv, "%d", &numPhilosophers);
+    return numPhilosophers;
+}
+
+// Takes in the number of philosophers, from 0 to N-1
+// Finishes when all philosophers have eaten twice
+void Philosopher(int numPhilosophers)
+{
+    int stateEatingCount[numPhilosophers];
+    while (true)
+    {
+        Think();                /*philosopher is thinking*/
+        TakeForks(numPhilosophers);          /*acquire two forks or block*/
+        Eat();                  /*yum-yum, spaghetti*/
+        PutForks(numPhilosophers);           /*put both forks back on table*/
+    }
+}
+
+void PutForks(int selectedPhilosopher)           /*i: philosopher number, from 0 to N-1*/
+{
+    Down(&mutex);               /*enter critical region*/
+    printf("%d is now thinking.\n", selectedPhilosopher);
+    philosopherState[selectedPhilosopher] = THINKING;        /*record fact that philosopher i is hungry*/
+    Test((i+N-1)%N);                 /*try to acquire 2 forks*/
+    Test(RIGHT);                /*exit critical region*/
+    Up(&mutex);                 /*block if forks were not acquired*/
+}
+
+// Takes in a number for a selected philosopher, from 0 to N-1
+void TakeForks(int selectedPhilosopher)
+{
+    Down(&mutex);               /*enter critical region*/
+    philosopherState[selectedPhilosopher] = HUNGRY;          /*philosopher has finished eating*/
+    Test(selectedPhilosopher, );                    /*see if left neighbor can now eat*/
+    Up(&mutex);                 /*see if right neighbor can now eat*/
+    Down(&philosopherSemaphore[selectedPhilosopher]);                /*exit critical region*/
+}
+
+// Takes in the number of philosophers, from 0 to N-1
+// Checks if left and right philosopher is not eating,
+//      and philosopher is hungry, then philosopher will eat
+void Test(int selectedPhilosopher)
+{
+    if (philosopherState[selectedPhilosopher] != HUNGRY)
+        return;
+    if (philosopherState[(selectedPhilosopher+N-1)%N LEFT] == EATING)
+        return;
+    if (philosopherState[RIGHT] == EATING)
+        return;
+    philosopherState[selectedPhilosopher] = EATING;
+    Up(&philosopherSemaphore[selectedPhilosopher]);
+}
+
+void Think(int selectedPhilosopher)
+{
+    printf("Function Think() was called.\n");
+}
+
+// Pick up for on left and right
+// (Right fork is owned by selectedPhilosopher number for consistency)
+void Up(sem_t* selectedSemaphore)
+{
+    printf("Function Up() was called.\n");
+}

TestDining.sh

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+#!/bin/bash
+rm DiningPhilosophers
+gcc DiningPhilosophers.c -o DiningPhilosophers
+./DiningPhilosophers 5