import struct
def tlvs(data):
'''TLVs parser generator'''
while data:
try:
type, length = struct.unpack('!HH', data[:4])
value = struct.unpack('!%is'%length, data[4:4+length])[0]
except:
print "Unproper TLV structure found: ", (data,)
break
yield type, value
data = data[4+length:]
########### example ####################################
# building network ordered data as TLVs list
a = struct.pack('!HHI', 1,4,2) # first tlv
a+= struct.pack('!HHI', 3,4,4) # second tlv
a+= struct.pack('!HHII', 5,8,6,6) # third tlv
a+= struct.pack('!HH', 2,3) # unproper tlv
# using TLV parser generator
for type, data in tlvs(a):
print type, (data,) #trick for print binary data
'''Produced output:
1 ('\x00\x00\x00\x02',)
3 ('\x00\x00\x00\x04',)
5 ('\x00\x00\x00\x06\x00\x00\x00\x06',)
Unproper TLV structure found: ('\x00\x02\x00\x03',)
'''
