From: Bob Hutchison <hutch@...>
Date: 2007-08-03T22:00:29+09:00
Subject: Re: Fast implementation of XML escape

Hi Robert,

Thanks for the response.


On 3-Aug-07, at 8:47 AM, Robert Klemme wrote:
>
> You are on the right track. There is just one thing to improve: get
> rid of "case":
>
> class Converter
>   MAP = {
>     "&" => "&amp;",
> # ...
>   }
>
>   def self.convert(s)
>     s.gsub(/[&<>'"]/) do |m|
>       MAP[m] || "ERROR"
>     end
>   end
> end


My version3 was:

@@convert = {
   '&' => '&amp;',
   '<' => '&lt;',
   '>' => '&gt;',
   "'" => '&apos;',
   '"' => '&quot;'
}

def version3(input)
   # all kinds of other processing of input simulated by the input.dup
   result = input.dup

   result.gsub!(/[&<>'"]/) do | match |
     @@convert[match]
   end

   return result
end

which is pretty much what you suggested, but it takes 29.71 seconds  
(rather than 8.74 seconds).

>
> Also, I believe x.dup.gsub! is less efficient than doing just a  
> single x.gsub.

That dup is just so I could 1) simulate some extra work that I had to  
do; and 2) make sure I didn't permanently change the test string with  
the gsub!.

Thanks!

Cheers,
Bob

>
> Kind regards
>
> robert
>

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