in reply to Re^3: Regex overlap in MAC address
in thread Regex overlap in MAC address

how about trying these? just playing with your fastest and adding sentinal ':'s before processing and removing them after. 
   zen3 => 'my $mac = ":".$data.":"; $mac =~ s/(?<=:)(?=[0-9a-fA-F](?:
+:))/0/g;
                                     $mac =~ s/^:|:$//; $mac;',

   zen4 => 'my $mac = ":$data:"; $mac =~ s/(?<=:)(?=[0-9a-fA-F](?::))/
+0/g;
                                 $mac =~ s/^:|:$//; $mac;',

   zen5 => 'my $mac = ":$data:"; $mac =~ s/(?<=:)(?=[0-9a-fA-F](?::))/
+0/g;
                                 $mac = substr $mac, 1,-1; $mac;',

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my results are varied: 
             Rate     zen2     zen3 ike_fast     zen4     zen5
zen2     152990/s       --      -1%      -1%      -4%      -6%
zen3     154915/s       1%       --      -0%      -3%      -5%
ike_fast 155051/s       1%       0%       --      -3%      -5%
zen4     159115/s       4%       3%       3%       --      -2%
zen5     162584/s       6%       5%       5%       2%       --

             Rate     zen2 ike_fast     zen4     zen3     zen5
zen2     147082/s       --      -3%      -3%      -3%      -5%
ike_fast 150866/s       3%       --      -0%      -1%      -3%
zen4     151345/s       3%       0%       --      -1%      -3%
zen3     152312/s       4%       1%       1%       --      -2%
zen5     155404/s       6%       3%       3%       2%       --

             Rate     zen2 ike_fast     zen4     zen5     zen3
zen2     132209/s       --      -1%      -4%     -10%     -13%
ike_fast 134054/s       1%       --      -3%      -9%     -11%
zen4     137554/s       4%       3%       --      -6%      -9%
zen5     147053/s      11%      10%       7%       --      -3%
zen3     151234/s      14%      13%      10%       3%       --

             Rate     zen2 ike_fast     zen3     zen4     zen5
zen2     148516/s       --      -2%      -3%      -4%      -7%
ike_fast 151827/s       2%       --      -1%      -1%      -5%
zen3     153467/s       3%       1%       --      -0%      -4%
zen4     153946/s       4%       1%       0%       --      -4%
zen5     159757/s       8%       5%       4%       4%       --

[download]

Replies are listed 'Best First'.
Re^5: Regex overlap in MAC address
by ikegami (Patriarch) on Sep 12, 2006 at 19:11 UTC
    No fair changing the initialization code. It can't be change since the OP's modification was done in-place. 
       zen3 => 'my $mac = $data; $mac = ":" . $data . ":";
                             $mac =~ s/(?<=:)(?=[0-9a-fA-F](?::))/0/g;
                             $mac =~ s/^:|:$//; $mac;',

   zen4 => 'my $mac = $data; $mac = ":$data:";
                             $mac =~ s/(?<=:)(?=[0-9a-fA-F](?::))/0/g;
                             $mac =~ s/^:|:$//; $mac;',

   zen5 => 'my $mac = $data; $mac = ":$data:";
                             $mac =~ s/(?<=:)(?=[0-9a-fA-F](?::))/0/g;
                             $mac = substr $mac, 1,-1; $mac;',

    [download]

    Fixing that didn't affect the result, however. 

                 Rate jwkrahn1 skeeve jwkrahn2 ike_orig ike_fast   zen4   
+zen3  zen5
jwkrahn1  62625/s       --    -4%      -4%     -12%     -36%   -42%   
+-43%  -44%
skeeve    65186/s       4%     --      -0%      -8%     -33%   -40%   
+-40%  -42%
jwkrahn2  65395/s       4%     0%       --      -8%     -33%   -40%   
+-40%  -42%
ike_orig  71122/s      14%     9%       9%       --     -27%   -34%   
+-35%  -37%
ike_fast  97408/s      56%    49%      49%      37%       --   -10%   
+-11%  -13%
zen4     108516/s      73%    66%      66%      53%      11%     --   
+ -1%   -4%
zen3     109083/s      74%    67%      67%      53%      12%     1%   
+  --   -3%
zen5     112484/s      80%    73%      72%      58%      15%     4%   
+  3%    --

    [download]

    Your three are equally fast, and slightly faster than the previous best.

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