def decodeHandshake(message):
length = binaryToShortInt(message[0])
proto = message[1:20]
reserved = message[20:28]
infoHash = message[28:48]
peerId = message[48:68]
return length, proto, reserved, infoHash, peerId
def decodeMessage(message):
length = binaryToLongInt(message[:4])
if length==0:
#keepalive
result = (-1, None)
else:
numericMessageTyp = binaryToShortInt(message[4])
if numericMessageTyp<0 or numericMessageTyp>8:
#unknown messagetype
result = (-2, None)
elif numericMessageTyp>=0 and numericMessageTyp<=3 and length==1:
#choke, unchoke, interested, notinterested
result = (numericMessageTyp, None)
elif numericMessageTyp==4 and length==5:
#have
result = (numericMessageTyp, binaryToLongInt(message[5:9]))
elif numericMessageTyp==5:
#bitfield
result = (numericMessageTyp, binaryToBin(message[5:]))
elif numericMessageTyp==6 and length==13:
#request
result = (numericMessageTyp, (binaryToLongInt(message[5:9]),\
binaryToLongInt(message[9:13]),\
binaryToLongInt(message[13:17])))
elif numericMessageTyp==7:
#piece
result = (numericMessageTyp, (binaryToLongInt(message[5:9]),\
binaryToLongInt(message[9:13]),\
message[13:]))
elif numericMessageTyp==8 and length==13:
#cancel
result = (numericMessageTyp, (binaryToLongInt(message[5:9]),\
binaryToLongInt(message[9:13]),\
binaryToLongInt(message[13:17])))
else:
#corrupt message
result = (None, None)
return result
