Separating IP nodes

[Brad Knotwell]

"John W. Baxter" <jwbnews at scandaroon.com> writes:
> My temptation would be to convert the dotted string form of the IP 
> address to a (long) integer, catching errors, add one, and convert back 
> to a dotted string (catching the error that the user put in 
> 255.255.255.255 which has become the pseudo IP 1.0.0.0.0).
> 
> Functions (methods) to do this are in...(oops, as I've never needed 
> them, I had to try to find the code...and I've failed so far).

Here's a good start (NOTE:  they assume a reasonable input)

def ipv4_cvt((first,second,third,fourth)):
    return (first << 24L) + (second << 16) + (third << 8) + fourth

def ipv4_uncvt2(addr,shift = (24,16,8,0),res = ()):
    octet = (addr >> shift[0])
    res = res + (octet,)
    if not shift[0]:
        return res
    else:
        return ip_uncvt2(addr - (octet * (256L << shift[1])),shift[1:], res)

maxaddr = ipv4_cvt([255,255,255,255])
myaddr =  ipv4_cvt([10,100,200,255])

if myaddr >= maxaddr:
    raise 'BadIpAddress'
else:
    print ip_uncvt(myaddr+1)

> John W. Baxter   Port Ludlow, WA USA  jwbnews at scandaroon.com

--Brad