# Calculate internet checksum for any arbitrary length variable amount of binary numbers
def checksum(*args):
	length = len(bin(args[0])) - 2
	result = 0
	for arg in args:
		result += arg
		if result > (2 ** length) - 1:
			result = (result & ((2 ** length) - 1)) + 1
	return result ^ ((2 ** length) - 1)


def e2e_delay(P, L, N, R):
	# P = propagation speed
	# L = packet length
	# N = number of packets
	# R = transmission rate
	return (P - 1) * (L / R) + N * (L / R)


def estimate_e2e_delay(PS, T):
	# PS = packet size
	# T = Throughput
	return PS / T


def trans_delay(L, R):
	# L = packet length
	# R = transmission rate
	return L / R


def prop_delay(P, L):
	# P = propagation speed
	# L = packet length
	return P * L


def traffic_intensity(L, pps, R):
	# L = packet length
	# pps = packets per second
	# R = transmission rate
	return (L * pps) / R


def cs_time(N, F, U):
	# N = Number of copies
	# F = File size
	# U = Server upload rate
	return (N * F) / U


def cs_time_n_clients(N, F, U, D):
	# N = Number of copies
	# F = File size
	# U = Server upload rate
	# D = Client download rate
	return max(cs_time(N, F, U), F / D)


def p2p_time(N, F, U, CD, D):
	# N = Number of copies
	# F = File size
	# U = Server upload rate
	# CU = Client upload rate
	# D = Client download rate
	return max((F / U), (N * F) / (U + (N * CD)), F / D)


def utilisation(L, R, RTT):
	# L = packet length
	# R = transmission rate
	# RTT = round trip time
	return (L / R) / (L / R + RTT)


def utilisation_pipeline(L, R, RTT, N):
	# L = packet length
	# R = transmission rate
	# RTT = round trip time
	# N = window size
	return N / (1 + (RTT / (L / R)))


def print_byte_tables():
	print("Byte Conversion Table")
	print("1 B = 8 bits")
	print("kB = 1024 bytes")
	print("MB = 1024 kB")
	print("GB = 1024 MB")
	print("TB = 1024 GB")


def man():
	print("checksum(0b, 0b,)")
	print("e2e_delay(P, L, N, R)")
	print("estimate_e2e_delay(PS, T)")
	print("trans_delay(L, R)")
	print("prop_delay(P, L)")
	print("traffic_intensity(L, pps, R)")
	print("cs_time(N, F, U)")
	print("cs_time_n_clients(N, F, U, D)")
	print("p2p_time(N, F, U, CD, D)")
	print("utilisation(L, R, RTT)")
	print("utilisation_pipeline(L, R, RTT, N)")
	print("print_byte_tables()")