python ip格式转化为long型

#!/usr/bin/env python
# -*- coding: utf-8 -*-

#ip转化为long型格式
def iptolong(ipaddr):
    data = 0L
    ip = ipaddr.split('.')
    for i in range(0,len(ip)):
        if 0 <= long(ip[i]) < 256:
            data = data+long(ip[i])*(256**(3-i))
        else:
            data = 0L
            break
    return data

#long型转化成ip格式
def longtoip(iplong):
    i_4 = iplong % 256
    i_3 = (iplong - i_4)/256 % 256
    i_2 = (iplong - i_3*256 - i_4)/256**2 % 256
    i_1 = (iplong - i_2*256*256 - i_3*256 - i_4)/256**3 % 256
    ip = str(i_1)+'.'+str(i_2)+'.'+str(i_3)+'.'+str(i_4)
    return ip