A general semaphore implementation

gensem.py

class Semaphore:
	def init(self, n):
		self.lock = BinSemaphore(1)
		self.delay = BinSemaphore(0)
		self.var = n
		
	def wait(self):
		self.lock.wait()
		self.var = self.var - 1
		if self.var < 0:
			self.lock.signal()
			self.delay.wait()
		else:
			self.lock.signal()
		
	def signal(self):
		self.lock.wait()
		self.var = self.var + 1
		if self.var <= 0:
			self.delay.signal()
		self.lock.signal()

Note: Assumes BinSemaphore(a standard boolean/binary semaphore) implementation.