void *threadFunc(void *arg){
struct cart_t *cart;
struct queue_info *info = (struct queue_info *)arg;
fprintf(stderr, "thread for direction %c starts\n", info->dir);
pthread_barrier_wait(&barrier);
cart = q_getCart(info->dir);
while(1){
if(allFinished() == 1) break;
if(cart == NULL){
finishes[info->thread_index] = 1;
}
else{
fprintf(stderr, "thread for direction %c gets cart %i\n", info->dir, cart->num);
monitor_arrive(cart);
monitor_cross(cart);
monitor_leave(cart);
cart = q_getCart(info->dir);
}
}
fprintf(stderr, "thread for direction %c exits\n", info->dir);
pthread_barrier_wait(&barrier);
return (void *) 1;
}
/*
* Each thread repeatedly does this:
*
* Try to get a cart off the head of the indicated queue.
* If there is no cart on that queue, return.
* If a cart is obtained, then:
* 1. "arrive" at intersection -- may have to wait until signaled
* 2. proceed into intersection once intersection is free & it becomes our turn
* 3. leave intersection & signal closest non-empty queue to the right
*/
void *moveCart(void *args) {
char direction = *(char *)args;
struct cart_t *cart;
fprintf(stderr, "thread for direction %c starts\n", direction);
cart = q_getCart(direction);
while (cart != NULL) {
fprintf(stderr, "thread for direction %c removes cart %i from head of queue\n", direction, cart->num);
monitor_arrive(cart);
monitor_cross(cart);
monitor_leave(cart);
cart = q_getCart(direction);
}
#if 1
(void) pthread_barrier_wait(&endBarrier);
#endif
fprintf(stderr, "thread for direction %c ends\n", direction);
return NULL;
}
void *west(void *arg)
{
char direction;
struct cart_t *cart;
direction = 'w';
fprintf(stderr, "thread for direction %c starts\n", direction);
cart = q_getCart(direction);
while (cart != NULL) {
fprintf(stderr, "thread for direction %c gets cart %i\n",
direction, cart->num);
monitor_arrive(cart);
monitor_cross(cart);
monitor_leave(cart);
cart = q_getCart(direction);
}
fprintf(stderr, "thread for direction %c exits\n", direction);
return NULL;
}
/*
* Function that each direction thread runs.
* Gets the next cart from that direction queue if possible and passes it to the monitor.
*/
void *cart(void* args) {
arg_t* actual;
char direction;
actual = (arg_t*) args;
direction = actual->direction;
struct cart_t *cart;
fprintf(stderr, "\n** Direction %c thread starts **\n", direction);
cart = q_getCart(direction);
while (cart != NULL) {
fprintf(stderr, "\nDirection %c thread gets cart %i\n", direction, cart->num);
monitor_arrive(cart);
monitor_cross(cart);
monitor_leave(cart);
cart = q_getCart(direction);
}
fprintf(stderr, "\n** Direction %c thread exits **\n", direction);
}