IPv4 Integer Conversion Function

Question

Write the shortest function to convert an IP address into it's integer representation and output it as an integer.

To change an IPv4 address to it's integer representation, the following calculation is required:

• Break the IP address into it's four octets.
• (Octet1 * 16777216) + (Octet2 * 65536) + (Octet3 * 256) + (Octet4)

Sample Input

192.168.1.1           10.10.104.36           8.8.8.8

Sample Output

3232235777            168454180              134744072

Answer 1

C# – 77 chars

Func<string,uint>F=s=>s.Split('.').Aggregate(0u,(c,b)=>(c<<8)+uint.Parse(b));

Answer 2

Haskell - 14 chars

(.) a=(256*a+)

usage in GHCi:

Prelude> let (.) a=(256*a+)
Prelude> 192. 168. 0. 1
3232235521

The only problem is that you have to put spaces left or right of the dot, otherwise the numbers will be interpreted as floating point.

Answer 3

Python (No eval) - 67

c=lambda x:long(''.join(["%02X"%long(i) for i in x.split('.')]),16)

Answer 4

Perl, 14 characters:

sub _{unpack'L>',pop}

# Example usage
print _(10.10.104.36) # prints 168454180

Answer 5

Ruby (40)

q=->x{x.gsub(/(\d+)\.?/){'%02x'%$1}.hex}

->

q["192.168.1.1"]
=> 3232235777

Answer 6

Perl with builtins (35):

unpack"N",pack"C4",split/\./,shift;  

Perl without builtins (42):

split/\./,shift;$s+=$_<<@_*8while$_=shift;

Answer 7

Scala 59 chars:

def f(i:String)=(0L/:i.split("\\.").map(_.toInt))(_*256+_)

Answer 8

C (91)

Not going to win anyway, so I tried to be a bit creative. Tested on 32-bit GCC 4.4.3.

main(a,c,b)char**c,*b;{c=c[1];for(b=&a+1;c=strtok(c,".");c=0)*--b=atoi(c);printf("%u",a);}

Answer 9

ASM - 98 byte executable (WinXP command shell), about 485 characters

Assemble using A86. Badly formed IP addresses generate undefined output.

    mov si,82h
    mov di,10
    mov bp,l3
    fldz
    push l2
    push l0
    push l0
    push l0
 l0:xor ax,ax
    xor cx,cx
 l1:add ax,cx
    mov [bp+di],ax
    mul di
    mov cx,ax
    lodsb
    sub al,'0'
    jnc l1
    fild w[bp]
    fmulp
    fild w[bp+di]
    faddp  
    ret
 l2:fbstp [si]
    mov bx,di
    mov di,bp
 l4:dec bx
    jz l5
    mov al,[si+bx-1]
    aam 16
    add ax,'00'
    xchg al,ah
    stosw
    jmp l4
 l5:mov al,'$'
    stosb
    lea di,[bp-1]
 l6:inc di
    cmp b[di],'0'
    je l6
 l7:cmp b[di],al
    jne l8
    dec di
 l8:mov dx,di
    mov ah,9
    int 21h
    ret
 l3:dw 256

Answer 10

C: 79 characters

main(i,a)char**a;{i=i<<8|strtol(a[1],a+1,0);*a[1]++?main(i,a):printf("%u",i);}

EDIT: removed C++, would not compile without headers; with GCC, the printf and strtol function calls trigger built-in functions, hence headers can be skipped. Thx to @ugoren for the tips. This will compile as is without additional options to gcc.

EDIT2: return is actually redundant :)

Answer 11

Powershell - 53

Variation on Ty Auvil's answer, which is a variation on Joey's answer:

%{([ipaddress]($_.split('.')[3..0]-join'.')).address}

PS C:\> '192.168.1.1' | %{([ipaddress]($_.split('.')[3..0]-join'.')).address}
3232235777
PS C:\> '10.10.104.36' | %{([ipaddress]($_.split('.')[3..0]-join'.')).address}
168454180
PS C:\> '8.8.8.8' | %{([ipaddress]($_.split('.')[3..0]-join'.')).address}
134744072

I would have just made a suggestion in the comments, but not enough rep.

Answer 12

Ruby (no builtins/eval) - 47

s=->s{s.split(".").inject(0){|a,b|a<<8|b.to_i}}

Test:

s["192.168.1.1"]
3232235777

Answer 13

PHP (no builtins/eval) - 54

<foreach(explode(".",$argv[1])as$b)$a=@$a<<8|$b;echo$a;

Answer 14

PowerShell 66 61

Variation on Joey's answer:

filter I{([ipaddress](($_-split'\.')[3..0]-join'.')).address}

PS C:\> '192.168.1.1' | I
3232235777
PS C:\> '10.10.104.36' | I
168454180
PS C:\> '8.8.8.8' | I
134744072

Answer 15

Befunge - 2x11 = 22 characters

So close, Befunge will win one day.

>&+~1+#v_.@
^*4*8*8<

Explanation

The biggest distinguishing feature of Befunge is that instead of being a linear set of instructions like most languages; it is a 2d grid of single character instructions, where control can flow in any direction.

>      v
^      <

These characters change the direction of control when they are hit, this makes the main loop.

 &+~1+

This inputs a number and pushes it onto the stack (&), pops the top two values off the stack, adds them and pushes them back onto the stack (+), inputs a single character and places its ascii value on the stack (~), then pushes 1 onto the stack and adds them (1+).

The interpreter I've been using returns -1 for end of input, some return 0 instead so the 1+ part could be removed for them.

      #v_.@

The # causes the next character to be skipped, then the _ pops a value off the stack and if it is zero sends control right, otherwise sends it left. If the value was zero . pops a value off the stack and outputs it as an integer and @ stops the program. Otherwise v sends control down to the return loop.

^*4*8*8<

This simply multiplies the top value of the stack by 256 and returns control to the start.

Answer 16

Golfscript -- 16 chars

{[~]2%256base}:f

As a standalone program, this is even shorter at 11.

~]2%256base

Extremely straightforward. Evaluates the input string (~) and puts it into an array []. Since the .s in the string duplicate the top of the stack, we only take every other term in the array (2%). We now have an array which basically represents a base 256 number, so we use a built-in function to do the conversion. (256base).

Answer 17

Perl : DIY ( for oneliners. )(40)

$j=3;$i+=($_<<($j--*8))for split/\./,$x;

# Use value in $i

DIY Function(65):

sub atoi{my($i,$j)=(0,3);$i+=($_<<($j--*8))for split'.',shift;$i}

Answer 18

Python 3.2 (69)

sum((int(j)*4**(4*i)) for i,j in enumerate(input().split('.')[::-1]))

Answer 19

PHP - 21 Characters

<?=ip2long($argv[1]);

Answer 20

MySQL - 20 Characters

SELECT INET_ATON(s);

Answer 21

D: 84 Characters

uint f(S)(S s)
{
    uint n;
    int i = 4;

    foreach(o; s.split("."))
        n += to!uint(o) << 8 * --i;

    return n;
}

Answer 22

Befunge-93 - 36 characters

&"~"2+::8****&884**:**&884***&++++.@

Answer 23

JavaScript (53/57 characters)

57 characters: This will work in Firefox only, as it uses the .reduce() Array method introduced in ES5 and Mozilla's proprietary "expression closure" feature.

function f(x)x.split('.').reduce(function(p,c)p<<8|c)>>>0

Alexandru's "eval" approach saves four characters:

function f(x)eval('((('+x.replace(/\./g,'<<8)+'))>>>0

Answer 24

C++ - lots of chars

#include <boost/algorithm/string.hpp>
#include <string>
#include <vector>
uint f(std::string p)
{
        std::vector<std::string> x;
        boost::split(x,p,boost::is_any_of("."));
        uint r=0;
        for (uint i = 0; i < x.size(); i++)
                r=r*256+atoi(x[i].c_str());
        return r;
}

Answer 25

C# - 120 Characters

float s(string i){var o=i.Split('.').Select(n=>float.Parse(n)).ToList();return 16777216*o[0]+65536*o[1]+256*o[2]+o[3];}

My first code golf - be gentle ;)

Answer 26

Python 56 45

c=lambda x:eval('((('+x.replace('.','<<8)+'))

Answer 27

Windows PowerShell, 70

Naïve approach:

filter I{[int[]]$x=$_-split'\.'
$x[0]*16MB+$x[1]*64KB+$x[2]*256+$x[3]}

With using System.Net.IPAddress: 76

filter I{([ipaddress]($_-replace('(.+)\.'*3+'(.+)'),'$4.$3.$2.$1')).address}

Test:

> '192.168.1.1'|I
3232235777

Answer 28

Golfscript - 21 chars

{'.'/{~}%{\256*+}*}:f

Answer 29

Ruby - 46 chars

require"ipaddr"
def f s;IPAddr.new(s).to_i;end