IP addresses range

Question

Given an IP address and mask like 192.168.10.30/24 on STDIN, return the matching range of addresses.

i.e. input : 192.168.10.30/24 output: 192.168.10.0-192.168.10.255

input : 127.0.0.0/31 output: 127.0.0.0-127.0.0.1

libraries/packages/... are NOT allowed

Answer 1

Ruby 1.8.7 - 166 162 142 characters

now works on 1.8.6 also

def s x;[24,16,8,0].map{|i|255&x>>i}*"."end
l=gets.split /\D/
r=1<<32-l.pop.to_i
i=0;l.map{|x|i=(i<<8)+x.to_i}
puts"#{s r*i/=r}-#{s r*i+r-1}"

Answer 2

C - 176 characters

updated due to gwell's suggestions:

f(unsigned v,int c){v>>8?f(v>>8,46):0;printf("%d%c",v&255,c);}main(){int a,b,c,d,e;scanf("%d.%d.%d.%d/%d",&a,&b,&c,&d,&e);a=a<<24|b<<16|c<<8|d;b=~0<<32-e;f(a&b,45);f(a|~b,10);}    

Answer 3

J, 97 110 characters

' .'charsub deb({.,'-',{:)":(4$256)#:#.(({:a){.(32$2)#:256#.}:a),"1]0 1$"0~{:32-a=:".'. /'charsub

Usage:

    ' .'charsub deb({.,'-',{:)":(4$256)#:#.(({:a){.(32$2)#:256#.}:a),"1]0 1$"0~{:32-a=:".'. /'charsub'127.0.0.0/31'
127.0.0.0-127.0.0.1

    ' .'charsub deb({.,'-',{:)":(4$256)#:#.(({:a){.(32$2)#:256#.}:a),"1]0 1$"0~{:32-a=:".'. /'charsub'192.168.10.30/24'
192.168.10.0-192.168.10.255

Answer 4

Python, 190 175 172 169 165 chars

l,m=raw_input().split('/')
m=2**(32-int(m))-1
i=0
for k in l.split('.'):i=256*i+int(k)
i&=~m
print'-'.join('.'.join(str(k>>j&255)for j in(24,16,8,0))for k in(i,i|m))

Answer 5

Lua, 181 165 characters

k=256 w=io.write
i=io.read():gmatch("%d+")a=((i()*k+i())*k+i())*k+i()c=2^(32-i())a=a-a%c
function p(n)if n>k then p((n-n%k)/k)w"."end w(n%k)end
p(a)w"-"p(a+c-1)w"\n"

Answer 6

Ruby 1.9, 135 134 characters

r=->i{[i].pack(?N).unpack('C*')*?.}
n=gets.split(/\D/).map &:to_i
b=(1<<32-n.pop)-1
h=n.pack('C*').unpack(?N)[0]|b
puts r[h^b]+?-+r[h]

Answer 7

Perl 134 chars

linefeeds for "readability" may be omitted

sub _{join'.',unpack'C4',pack'B*',@_}
split '[./]',<>;
$m=1x($n=pop@_).'0'x(32-$n);
$b=$m&unpack'B*',pack'C4',@_;
print _($b),'-',_$b|=~$m