http://www.perlmonks.org?node_id=158459


in reply to Check IP with support for CIDR

You can simplify the CIDR mask check: 
return unpack ('N', pack ('C4', split /\./, $i) ^ pack ('C4', split /\
+./, $1)) >> 32 - $2;

[download]
   MeowChow                                   
               s aamecha.s a..a\u$&owag.print

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Re: (MeowChow) Re: Check IP with support for CIDR
by xaphod (Monk) on Apr 12, 2002 at 08:06 UTC
    Could not get that to work. However, it did make me think and hence this: 
    return ( (unpack('N',pack('C4',split(/\./,$i))) ^ unpack('N',pack('C4'
+,split(/\./,$1)))) >> (32-$2) ) == 0;

    [download]
    --
    TTFN, FNORD
[reply]
[d/l]
      My bad, I forgot to negate the result: 
      return not unpack ('N', pack ('C4', split /\./, $i) ^ pack ('C4', spli
+t /\./, $1)) >> 32 - $2;

      [download]
         MeowChow                                   
               s aamecha.s a..a\u$&owag.print
[reply]
[d/l]
        That works. So I guess you win this round of Golf.
        --
        TTFN, FNORD

        xaphod
[reply]

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