in reply to Dotless IP address problem

Just following the formulas on the web page: 
sub ip_to_dotless {
        return 0+ eval " 0x" . sprintf("%02x%02x%02x%02x", split(/\./,
+ shift));
}
sub dotless_to_ip {
        my $hex=reverse sprintf("%x", shift);
        my @ip;
        for(0..3) {
                push(@ip, 0+ eval "0x" . reverse substr($hex, 0, 2, ""
+));
        }
        join('.',  reverse @ip);
}

[download]
This seems to work nicely.

Replies are listed 'Best First'.
Re: Re: Dotless IP address problem
by guha (Priest) on Oct 19, 2001 at 00:46 UTC
    A slight twist which works for your two examples anyway. 
    sub dotless_to_ip {
    #use integer;
    my $dotless = shift;
    my $index   = 3;
    my @ip      = ();
    
    while ( @ip < 4 ) {
        my $temp = 256 ** $index--;
        push @ip, int($dotless / $temp) ;

        $dotless -= $ip[ -1 ] * $temp;
        
    }
    return join '.', @ip;
}

    [download]
    I guess one could attack the problem using binary shifts (>>) and bitwise and's as well.
[reply]
[d/l]

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