class SimpleBarrier:
#### sl 78
def __init__(self, N):
self.N = N
self.count = 0
self.m = Mutex()
#self.m = Semaphore(1) # mutex
self.b = Event() # barier
def barrier(self):
self.m.lock() #self.m.wait()
self.count += 1
self.m.unlock() #self.m.signal()
if self.count == self.N:
self.b.signal()
self.b.wait()
class Lightswitch:
def __init__(self):
self.count = 0
self.mutex = Mutex()
def lock(self, semaphore):
self.mutex.lock()
self.count += 1
if self.count == 1:
semaphore.wait()
self.mutex.unlock()
def unlock(self, semaphore):
self.mutex.lock()
self.count -= 1
if self.count == 0:
semaphore.signal()
self.mutex.unlock()
class SimpleBarrier:
"""
ADT, use only barrier()
"""
def __init__(self, n):
self.n = n
self.count = 0
self.mutex = Mutex()
self.turnstile = Semaphore(0)
def barrier(self):
self.mutex.lock()
self.count += 1
if self.count == self.n:
self.count = 0
self.turnstile.signal(self.n)
self.mutex.unlock()
self.turnstile.wait()
class EventBarrierOptimized:
"""
ADT, use only barrier()
"""
def __init__(self, n):
self.n = n
self.count = 0
self.mutex = Mutex()
self.event = Event()
def barrier(self):
self.mutex.lock()
if self.count == 0:
self.event.clear()
self.count += 1
if self.count == self.n:
self.count = 0
self.event.signal()
self.mutex.unlock()
self.event.wait()
class Lightswitch:
def __init__(self):
self.count = 0
self.mutex = Mutex()
def lock(self, semaphore):
self.mutex.lock()
self.count += 1
if self.count == 1:
semaphore.wait()
self.mutex.unlock()
def unlock(self, semaphore):
self.mutex.lock()
self.count -= 1
if self.count == 0:
semaphore.signal()
self.mutex.unlock()
def lock_test(self, semaphore, t_id):
self.mutex.lock()
self.count += 1
if self.count == 1:
print("First thread walked in and turned on the light!")
print("thread_id = {:2d}, number of threads inside = {:2d}\n".format(t_id, self.count))
semaphore.wait()
else:
print("A thread walked in, but there already were some threads inside.")
print("thread_id = {:2d}, number of threads inside = {:2d}\n".format(t_id, self.count))
self.mutex.unlock()
def unlock_test(self, semaphore, t_id):
self.mutex.lock()
self.count -= 1
if self.count == 0:
print("Last thread walked out and turned off the light!")
print("thread_id = {:2d}, number of threads inside = {:2d}\n".format(t_id, self.count))
semaphore.signal()
else:
print("A thread walked out, but there are still some threads inside.")
print("thread_id = {:2d}, number of threads inside = {:2d}\n".format(t_id, self.count))
self.mutex.unlock()