in reply to Re (tilly) 5: how do I line-wrap while copying to stdout?
in thread how do I line-wrap while copying to stdout?

By the undef $/, the file is read in as a huge string. Of course I checked, and with a n=1000 string I get: 
          Rate  regex substr
regex  21775/s     --   -27%
substr 29748/s    37%     --

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Which makes sense, as my file has some 50k chars.

Jeroen
"We are not alone"(FZ)

Update: (I'm not going to make a Re:{9} post)

I'd say, start checking the source {grin} 

$str='a'x1E6; 
=>
         Rate  regex substr
regex  15.1/s     --   -16%
substr 18.0/s    19%     --
$str='a'x1E7;
=>
         Rate  regex substr
regex  1.41/s     --   -21%
substr 1.79/s    27%     --

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At 100M, I'm testing my swap ;-)..... I tried it nevertheless, but now I'm waiting for my box stop swapping... /me is afraid that may take a while... :-)... finally, I had to use that reboot button :-<
25M still went OK: 
       s/iter  regex substr
regex    1.80     --   -21%
substr   1.42    27%     --

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at 50M, benchmark produced a division by zero .....

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Re (tilly) 8: how do I line-wrap while copying to stdout?
by tilly (Archbishop) on Apr 20, 2001 at 19:20 UTC
    Oops, missed that.

    Still the principle that merlyn stated is correct, and is a common performance mistake in parsing. Try it with a 1 MB string. If substr still wins then I guarantee you that someone implemented a buffering strategy with strings and substr where doing a destructive substr at the beginning of a string just moves indexes around and does not recopy.

    Perl plays a lot of games like that, for instance that is why push, pop and friends are fast. I am just a little surprised to see it played on strings...

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