python - Encode two ipv4 addresses in 64 bits -

if have pairs of ip addresses like:

ip1="168.2.65.33" ip2="192.4.2.55" 

i encode each pair 64 bit value first 32 bits first ip address , second second ip address. able save 64 bit value file in such way can read in , recover 2 ip addresses.

the aim save space.

is possible in python?

don't worry encoding them in 64 bits. ipv4 address 32 bits (4 bytes). if write 2 of them file, 8 bytes in size.

use socket.inet_aton convert human-readable ip address string packed binary raw 4-byte string:

import socket ip_addrs = ["168.2.65.33", "192.4.2.55"]  open('data.out', 'wb') f:     ip in ip_addrs:         raw = socket.inet_aton(ip)         f.write(raw) 

result:

$ hexdump -cv data.out  00000000  a8 02 41 21 c0 04 02 37                           |..a!...7| 00000008 

the complementary conversion function socket.inet_ntoa convert packed 4-byte string human-readable ip address.

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here's example of writing , reading them back:

import socket  ip_pairs = [     ('1.1.1.1', '1.1.1.2'),     ('2.2.2.2', '2.2.2.3'),     ('3.3.3.3', '3.3.3.4'), ]  # write them out open('data.out', 'wb') f:     ip1, ip2 in ip_pairs:         raw = socket.inet_aton(ip1) + socket.inet_aton(ip2)         f.write(raw)  def read_with_eof(f, n):     res = f.read(n)     if len(res) != n:         raise eoferror     return res  # read them in result = [] open('data.out', 'rb') f:     while true:         try:             ip1 = socket.inet_ntoa(read_with_eof(f, 4))             ip2 = socket.inet_ntoa(read_with_eof(f, 4))             result.append((ip1, ip2))         except eoferror:             break  print 'input:', ip_pairs print 'result:', result 

output:

$ python pairs.py  input: [('1.1.1.1', '1.1.1.2'), ('2.2.2.2', '2.2.2.3'), ('3.3.3.3', '3.3.3.4')] result: [('1.1.1.1', '1.1.1.2'), ('2.2.2.2', '2.2.2.3'), ('3.3.3.3', '3.3.3.4')]