int dispatch_add_edge(char *params, network *net) {
char *first_param = NULL, *second_param = NULL, *third_param;
if (params[0] == '\0')
send_error(24);
else if (!isspace(params[0]))
send_error(3);
else if (check_and_get_three_params(params + 1, &first_param, &second_param,
&third_param) == FALSE) {
send_error(24);
return 1;
} else if ((check_string_is_non_negative_integer(first_param) == FALSE)
|| (check_string_is_non_negative_integer(second_param) == FALSE)) {
send_error(5);
return 1;
} else if (!check_string_is_double(third_param)) {
send_error(-4);
return 1;
} else {
int first_id = atoi(first_param);
int second_id = atoi(second_param);
double weight = strtod(third_param, NULL);
if ((is_legal_id(first_id, net) == FALSE)
|| (is_legal_id(second_id, net) == FALSE)) {
send_error(7);
return 1;
} else if (first_id == second_id) {
send_error(8);
return 1;
} else {
return add_edge(first_id, second_id, weight, net);
}
}
return 1;
}
int
binary_semaphore_create(int initial_value)
{
if(!initialized)
init_bsemaphores();
if(!is_legal_id(next_bsemaphore))
panic("binary semaphore overflow!");
acquire(&list_lock);
struct binary_semaphore *s = &bsemaphores[next_bsemaphore];
initlock(&s->lock, "bsemaphore_lock");
acquire(&s->lock);
s->id=next_bsemaphore;
int id=next_bsemaphore;
if(initial_value<=0)
s->value=0;
else
s->value=1;
init_queue(&s->waiting);
release(&s->lock);
next_bsemaphore++;
release(&list_lock);
return id;
}
int
binary_semaphore_down(int s_id)
{
acquire(&list_lock);
if(!is_legal_id(s_id) || !is_semaphore_init(s_id))
return -1;
struct binary_semaphore *s = &bsemaphores[s_id];
acquire(&s->lock);
if(s->value <= 0){
// Already locked
if(enque(proc, &s->waiting)<0){
// enque fails
release(&s->lock);
release(&list_lock);
//cprintf("[err %d %d]", proc->pid, s_id);
return -1;
}
//release(&s->lock);
//cprintf("[sleep %d %d]", proc->pid, s_id);
release(&list_lock);
sleep(proc, &s->lock);
release(&s->lock);
return 0;
}
//cprintf("[lock %d %d]", proc->pid, s_id);
s->value=0;
release(&s->lock);
release(&list_lock);
return 0;
}
int
binary_semaphore_up(int s_id)
{
acquire(&list_lock);
if(!is_legal_id(s_id) || !is_semaphore_init(s_id))
return -1;
struct binary_semaphore *s = &bsemaphores[s_id];
acquire(&s->lock);
void *p=0;
if(deque(&s->waiting, &p)<0){
// no waiting procs
//cprintf("[unlk %d %d]", proc->pid, s_id);
s->value=1;
release(&s->lock);
release(&list_lock);
return 0;
}
if(((struct proc*) p)->tid == proc->tid){
s->value=1;
//cprintf("[self %d %d]", proc->pid, s_id);
release(&s->lock);
release(&list_lock);
return binary_semaphore_up(s_id);
}
//release(&s->lock);
s->value=0;
//cprintf("[wake %d %d]", ((struct proc*) p)->pid, s_id);
wakeup((struct proc*) p);
release(&s->lock);
release(&list_lock);
return 0;
}