From: "Rebhan, Gilbert" <Gilbert.Rebhan@...>
Date: 2007-08-21T17:21:16+09:00
Subject: Re: Test if file is binary ?

 

-----Original Message-----
From: Robert Klemme [mailto:shortcutter@googlemail.com] 
Sent: Tuesday, August 21, 2007 9:41 AM
To: ruby-talk ML
Subject: Re: Test if file is binary ?

2007/8/21, Alex Gutteridge <alexg@kuicr.kyoto-u.ac.jp>:
> Sorry for the duplicate! Robert is too fast for me.

/*
It's always good to see more solutions.  I like the conciseness of
your solution. But I think this should rather be a class method
because you would not do the test on an open stream. Dunno which of
the solutions is more realistic.
*/

you mean it should be something like  ? =

class File
   def self.is_binary?(name)
     ascii = total = 0
     File.open(name, "rb") { |io| io.read(1024) }.each_byte  do |c|
	total += 1; 
	ascii +=1 if c >= 128  or c == 0
     end
     ascii.to_f / total.to_f > 0.33
   end
end


/*
Might be fun to let both approaches
test a large number of files and compare their results (probably also
with output from "file"). :-)
*/

Is there an exisiting standard what is considered as a binary file,
means a
rule like check the first block from a file and =

- if control characters (ASCII 0-32) and "high ASCII" (> 128) are found
>30 %
it's considered as binary file otherwise textfile

- if control characters (ASCII 0-32 and > 128) are found == 0 it's
always
considered as textfile

??


Regards, Gilbert