From: "Anders Engström" <aengstrom@...>
Date: 2005-01-13T00:26:38+09:00
Subject: Re: Comparing two files for equality

On Wed, Jan 12, 2005 at 09:11:17PM +0900, Florian Gross wrote:
> Edgardo Hames wrote:
> 
> >Hi everybody,
> 
> Moin.
> 
> >I tried to implement a program that
> >compares two files for equality. I came up with the following trivial
> >solution
> >
> >puts (IO.readlines file[0]) == (IO.readlines file[1])
> >
> >Have you got any other suggestions?
> 
> Not much different:
> 
> def files_equal?(*files)
>   files.map do |file|
>     File.size file
>   end.uniq.size <= 1 and
>   files.map do |file|
>     File.read file
>   end.uniq.size <= 1
> end
> 
> This ought to be slightly faster in the average case.
> 
> Other optimizations would be reading the files line-wise in parallel and 
> bailing out as soon as one of the lines differs.
> 

Another alternative - probably slow as h*ll, but...

    def files_equals?(*files)
        require 'digest/md5'

        return files.map do |file|
            Digest::MD5.hexdigest(File.read(file))
        end.uniq.size == 1
    end

//Anders

-- 
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