From: Peter Bailey <pbailey@...>
Date: 2006-05-10T03:58:15+09:00
Subject: Re: Problem with 2nd File.Read in small script.

Justin Collins wrote:
> Peter Bailey wrote:
>> require 'FileUtils'
>>      #If the page count is odd, then, add a blank to make it an even 
>>     blankpages.push($1)
>>     File.open(infofile + ".pageinfo", "w") do |writetext|
>>       writetext << "Number of blankpages in this PDF: 
>> #{blankpages.length}\n" <<
>>       "Blank Pages in This PDF: #{blankpages.join(' ')}\n"
>>     end
>>   end
>>   end
>> end
>>
>>   
> 
> I think part of the issue here is that you open the file for writing,
> then do a read on the same file. Looking at IO.read:
> 
> Opens the file, optionally seeks to the given offset, then returns
> /length/ bytes (defaulting to the rest of the file). read ensures the
> file is closed before returning.
> 
> But you have already opened the file. So, your structure above looks
> something like:
> 
> 
> File.open(psfile) { #opens psfile
> 
>     File.read(psfile) {  #opens psfile
> 
>     } #closes psfile
> 
>     File.read(psfile) { #opens psfile
> 
>     } #closes psfile
> 
> } #closes psfile
> 
> 
> I'm not sure if that is the problem or not.
> 
> -Justin


Thanks, Justin. Your comments made me dive deeper, and, it works! 
Obviously, there shouldn't be any reason why I couldn't read a file 
twice, or as many times as I needed. But, I did make it neater here, 
closing one read before starting another. . . .

require 'FileUtils'
Dir.chdir("c:/scripts/ruby/temp")
psfiles = Dir.glob('*.ps')

blankpages = []
totalpages = 0

psfiles.each do |psfile|
 infofile = File.basename(psfile, '.ps')
 #Scan for the number of pages in the original PDF.
 File.read(psfile).scan(/\%\%Pages: (\d{1,5})\n/) do
  File.open(psfile, "a") do |writepage|
   totalpages = $1
   #totalpages.push($1)
   #If the page count is odd, then, add a blank to make it an even page 
count.
   if (totalpages.to_i % 2) !=0 then
    writepage << "\%\%Blank page from Asura\nshowpage\n"
    totalpages = totalpages.to_i + 1.to_i
   end
end
end
 File.read(psfile).scan(/\%\%Page: [(\d)()]+ 
(\d{1,5})\n\%\%PageBoundingBox:
  \d{1,5} \d{1,5} \d{1,5} \d{1,5}\n\%\%PageOrientation:/) do
  blankpages = $1
  end
   File.open(infofile + ".pageinfo", "w") do |writetext|
    writetext << "Total number of pages in this PDF: #{totalpages}\n" 
<<\
    "Number of blank pages in this PDF: \
#{blankpages.length}\n" << "Blank Pages\              in This PDF: 
#{blankpages.join(' ')}\n"
			end
end


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