From: James Masters <james.d.masters@...>
Date: 2009-09-22T00:35:21+09:00
Subject: Re: Determining if a file is binary or text

On Sep 20, 2:17 am, Robert Klemme <shortcut...@googlemail.com> wrote:
> I fully agree: the difficult part is in deciding: what is a text file?
> If that has been clarified enough the algorithm for checking should
> become much more obvious.

I agree - this is what it comes down to.  BTW, I tried the following
on my project (using Find#find to get the tree) on the first 40
"lines" (which I know can theoretically be very short or long in a
"binary" file) and it seems to work for what I'm doing.  This works
well for me also because I'm checking for the presence of a header and
I can do this check along with checking for a header while the file is
still open:

line.match(/^[[:print:]\t\n\r]+$/)

But probably a better approach would be to use a ratio of characters
that are printable against those that may traditionally be non-
printable in the even that some "non-printable" characters are present
in a text file.  This is what SVN does (found the link from a post
from Xavier on a "ptools" website when I Googled it):

http://subversion.tigris.org/faq.html#binary-files

And it also appears to be what File#binary? is doing in ptools (I
checked the source code; thanks Dan for the pointer).