From: Siep Korteling <s.korteling@...>
Date: 2008-01-15T00:20:42+09:00
Subject: Re: Counting the files in a directory....

Robert Klemme wrote:
> 2008/1/12, Siep Korteling <s.korteling@gmail.com>:
>> > puts folder.Files.count
> Did you verify that this is faster?  I am skeptical because this call
> does basically the same: it gets the list of files in the directory
> and counts them.  I would expect a speedup only if there was an API
> function that would directly return the number of files.
> 
> Kind regards
> 
> robert

 require 'win32ole'
 require 'benchmark'
 ldirname = "C:/WINDOWS/system32" #2500+ files
 mdirname = "C:/ruby/lib/ruby/1.8" #800+ files
 sdirname="C:/ruby/lib/ruby/1.8/i386-mswin32" # 40+ files
  @fso = WIN32OLE.new("Scripting.FileSystemObject")
 n=500

    Benchmark.bmbm do |x|

   x.report("fso_mixed 
|"){n.times{fso(ldirname);fso(mdirname);fso(sdirname)}}
   x.report("Dir_mixed 
|"){n.times{dir(ldirname);dir(mdirname);dir(sdirname)}}
   x.report("fso_2500  |"){n.times{fso(ldirname)}}
   x.report("Dir_2500  |"){n.times{dir(ldirname)}}
   x.report("fso_800   |"){n.times{fso(mdirname)}}
   x.report("Dir_800   |"){n.times{dir(mdirname)}}
   x.report("fso_40    |"){n.times{fso(sdirname)}}
   x.report("Dir_40    |"){n.times{dir(sdirname)}}

   def fso(dirname)
     folder = @fso.GetFolder(dirname)
     count = folder.Files.count
   end

   def dir(dirname)
     count =  Dir.entries(dirname).size - 2
   end

end


results in:

                  user     system      total        real
fso_mixed |   0.360000   1.222000   1.582000 (  1.673000)
Dir_mixed |   3.635000   1.382000   5.017000 (  5.157000)
fso_2500  |   0.271000   1.071000   1.342000 (  1.362000)
Dir_2500  |   3.305000   1.282000   4.587000 (  4.697000)
fso_800   |   0.040000   0.120000   0.160000 (  0.160000)
Dir_800   |   0.170000   0.100000   0.270000 (  0.281000)
fso_40    |   0.020000   0.080000   0.100000 (  0.110000)
Dir_40    |   0.050000   0.071000   0.121000 (  0.120000)

Apparently, for small directories it doesn't make much difference. For 
large directories it does. (filesystem ntfs).


Siep
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