unmodfile.rb

# unmodfile.rb: Unpack a Starshatter data file
require 'zlib'
require 'ftools'

Header = Struct.new(:magic, :file_count, :index_size, :super_secret_drm_key, :index_offset)
Entry = Struct.new(:filename, :size_unpacked, :size, :offset)

File.open(ARGV[0] || 'shatter.dat', 'rb') do |f|
  hdr = Header.new(*f.read(20).unpack("i5"))
  f.pos = 20 + hdr.index_offset
  index = Zlib::Inflate.inflate(f.read(hdr.index_size))
  (0..(index.length-76)).step(76) do |i|
    p e = Entry.new(*index[i,76].unpack("Z64i3"))
    f.pos = 20 + e.offset
    File.makedirs(File.dirname(e.filename))
    File.open(e.filename, 'wb') { |o| o.write(Zlib::Inflate.inflate(f.read(e.size))) }
  end
end # 17 lines (15 SLOC)