Sunday, January 13, 2008

BinData for Ruby Fuzzers

Not that I'm into fuzzing binary protocols/file formats anymore. But if I still wasted my time on that sort of nonsense BinData looks useful enough for that sort of thang:

= BinData is a declarative way to read and write structured binary data.

This is a performance release. Execution speed has been doubled and memory usage has been decreased by about 25%.

== What is BinData?

Do you ever find yourself writing code like this?

io =
len ="v")
name =
width, height ="VV")
puts "Rectangle #{name} is #{width} x #{height}"

It's ugly, violates DRY and feels like you're writing Perl, not Ruby.

Here's how you'd write the above using BinData.

class Rectangle < BinData::Struct
. endian :little
. uint16 :len
. string :name, :read_length => :len
. uint32 :width
. uint32 :height

io =
r =
puts "Rectangle #{} is #{r.width} x #{r.height}"

BinData supports signed/unsigned integers, strings, null terminated strings, arrays, choices and user defined structures.

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