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IP address - long to dottedquad to long

by ruzam (Curate)
on Apr 28, 2006 at 19:47 UTC ( #546367=sourcecode: print w/replies, xml ) Need Help??
Category: Miscellaneous
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Description: Convert long integers to dotted quad notation string.
Convert dotted quad notation strings to long integer.

A couple of quick functions I've been using to convert IP addresses. I seem to be using these quite often.

Any and all comments/suggestions appreciated!

Thanks to jdporter and ikegami who have shown me a better way. The code here is credited to ikegami.
# thanks to jdporter and ikegami who have shown me a much better way t
+o do this!
#
# Thanks to ikegami for the code example

use Socket qw( inet_aton inet_ntoa );

sub DottedQuadToLong {
 # Accepts triton.littlefish.ca
 # Accepts 24.72.30.83
 # Accepts 407379539
 # etc
 return unpack('N', inet_aton(shift)); 
}

sub LongToDottedQuad {
 return inet_ntoa(pack('N', shift)); 
}
Replies are listed 'Best First'.
Re: IP address - Converting between string and number
by ikegami (Patriarch) on Apr 28, 2006 at 20:10 UTC

    Those are needlessly complicated. You're replicating functions inet_aton and inet_ntoa of the core module Socket:

    use Socket qw( inet_aton inet_ntoa ); sub DottedQuadToLong { # Accepts triton.littlefish.ca # Accepts 24.72.30.83 # Accepts 407379539 # etc return unpack('N', inet_aton(shift)); } sub LongToDottedQuad { return inet_ntoa(pack('N', shift)); }

    Here are alternatives that only use pack and unpack (but only accept addresses of the form a.b.c.d):

    sub DottedQuadToLong { return unpack('N', (pack 'C4', split(/\./, shift))); } sub LongToDottedQuad { return join('.', unpack('C4', pack('N', shift))); }
      Wow! Excellent (and nearly instant) advice! Thanks both of you.

      My use of regex was based on a very narrow definition of dotted quad I needed at the time. I'm totally in favor of using inet_aton and inet_ntoa instead!
Re: IP address - long to dottedquad to long
by jdporter (Chancellor) on Apr 28, 2006 at 20:06 UTC
Re: IP address - long to dottedquad to long
by davidrw (Prior) on Apr 28, 2006 at 20:20 UTC
    Net::IP solutions:
    # for just DottedQuadToLong(): use Net::IP; print Net::IP->new("24.72.30.83")->intip; # for both directions: use Net::IP qw/:PROC/; print ip_bintoint(ip_iptobin("24.72.30.83",4)); print ip_bintoip(ip_inttobin("407379539",4),4);

    couple code comments:
    • Personnally i'd write foreach (@quads) { $_ = hex } w/map: return join '.', map {hex} @quads;
    • in DottedQuadToLong, the split is just extra work -- just capture each piece (don't need the substitution, either)
      sub DottedQuadToLong { my $ip_str = shift; return 0 unless $ip_str =~ /^\s*(\d{1,3})\.(\d{1,3})\.(\d{1,3})\.( +\d{1,3})\s*$/; my $ip = 0; foreach my $quad ($1,$2,$3,$4){ return 0 if ($quad > 255); $ip = $ip * 256 + $quad; } return $ip; }
      Nice tips. I rarely use map (it scares me) so I never would have thought of trying that. The spilt I should have seen coming...

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