#include "./semaphore.h"
#include "../interrupt/guard.h"
#include "../thread/scheduler.h"
uint8_t counter;
Queue<Thread> waiting;
Semaphore::Semaphore(unsigned c) {
  counter=c;
}


void Semaphore::p(Vault &vault) { 
  //resource is frei, läuft direkt weiter
  if (vault.counter > 0)
    vault.counter--;
  else
  //thread block, zu aktueller queue hinzufügen und 
    waiting.enqueue(*vault.sch.active());  //was is der calling thread
                                           //
}

//release
void Semaphore::v(Vault &vault) { 
  Thread* first = waiting.dequeue();
  if (first != nullptr)
    vault.sch.ready(first);   //wakeup "first" thread
  else
    vault.counter++;
}