From: Andrew Johnson <ajohnson@...>
Date: 2006-03-19T14:08:48+09:00
Subject: Re: safe way to calc md5 on very large files

On Sun, 19 Mar 2006 13:49:51 +0900, ara.t.howard@noaa.gov
<ara.t.howard@noaa.gov> wrote:
> On Sun, 19 Mar 2006, Stephen Waits wrote:
>>
>> Close.. try this..
>>
>>    require 'md5'
>>    File.open(filename,'rb') { |f| MD5.hexdigest(f.read) }
>>
>> And yes, the file is closed with the block form of open.
>>
>> --Steve
> 
> i think the OP has the right approach - note that an 'f.read' will consume
> 2GB.  but the OP's code
> 
>    harp:~ > cat a.rb
>    require 'digest/md5'
>    md5 = Digest::MD5.new() and open(ARGV.shift, 'rb').each{|line| md5 << line}
>    p md5.hexdigest
> 
> will not.


In my reading of the OP, both the block-open and iteration are actually
desired:

  md5 = Digest::MD5.new
  File.open(file,'rb') do |ios|
    ios.each {|line| md5 << line }
  end

cheers,
andrew

-- 
Andrew L. Johnson   http://www.siaris.net/
      What have you done to the cat? It looks half-dead.
          -- Schroedinger's wife