#include "Semaphore.hh"

Semaphore::Semaphore()
{
  mutex = new pthread_mutex_t[1];
  condition = new pthread_cond_t[1];
  pthread_mutex_init( mutex, NULL );
  pthread_cond_init( condition, NULL );
  this->value = 1; 
}

Semaphore::Semaphore( int value )
{
  mutex = new pthread_mutex_t[1];
  condition = new pthread_cond_t[1];
  pthread_mutex_init( mutex, NULL );
  pthread_cond_init( condition, NULL );
  this->value = value;
}

Semaphore::~Semaphore()
{
  delete mutex;
  delete condition;
}

void 
Semaphore::up() 
{
  pthread_mutex_lock( mutex );

  value++;

  pthread_cond_signal( condition );

  pthread_mutex_unlock( mutex );
}

void 
Semaphore::bdown() 
{
  pthread_mutex_lock( mutex );

  value--;

  if( value < 0 )
    {
      pthread_cond_wait( condition, mutex );
    }
  
  pthread_mutex_unlock( mutex );
}

void 
Semaphore::nbdown() 
{
  pthread_mutex_lock( mutex );
  
  value--;
  
  pthread_mutex_unlock( mutex );
}

void 
Semaphore::set( int value ) 
{
  pthread_mutex_lock( mutex );
  
  this->value = value;
  
  pthread_mutex_unlock( mutex );
}

int 
Semaphore::get() 
{
  int rv;

  pthread_mutex_lock( mutex );
  
  rv = this->value;

  pthread_mutex_unlock( mutex );

  return rv;
}