From: Eric Hodel <drbrain@...7.net>
Date: 2006-09-11T05:53:45+09:00
Subject: Re: Using RubyInline for Optimization

On Sep 10, 2006, at 1:51 PM, Mike Berrow wrote:

> Eric Hodel wrote:
>> I wrote an article on using RubyInline for optimization where I take
>> png.rb, sprinkle in a little profiling and a little C and make it go
>> over 100 times faster.
>>
>> http://segment7.net/projects/ruby/inline_optimization.html
>>
>
> Hi, I installed the gems but I immediately run into this:
>
> C:\Inline\png-1.0.0>ruby -Ilib example/profile.rb
> example/profile.rb:8:in `draw': undefined method `to_blob' for
> #<PNG:0x28c7b28>
> (NoMethodError)
>
> Any idea?

 From the article:
== Play along at home!

If you want to play along at home, download and unpack png-1.0.0.tgz  
and save the profile benchmark code into example/.

I also added PNG#to_blob to eliminate the need to write the file to  
disk, it looks almost exactly like PNG#save:

def to_blob
   blob = []
   blob << [137, 80, 78, 71, 13, 10, 26, 10].pack("C*") # PNG signature
   blob << PNG.chunk('IHDR',
                     [ @height, @width, @bits, 6, 0, 0, 0 ].pack 
("N2C5"))
   # 0 == filter type code "none"
   data = @data.map { |row| [0] + row.map { |p| p.values } }.flatten
   blob << PNG.chunk('IDAT', Zlib::Deflate.deflate(data.pack("C*"), 9))
   blob << PNG.chunk('IEND', '')
   blob.join
end
I added my RubyInline extensions in png.rb and modified png.rb as  
appropriate, so while you play along you should do that too.


-- 
Eric Hodel - drbrain@segment7.net - http://blog.segment7.net
This implementation is HODEL-HASH-9600 compliant

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