rifftree.rb

def rifftree io, depth = 0, len = 0
  offset = io.pos
  while id = io.read(4) do
    if len > 0 && io.pos >= offset + len
      io.pos -= 4
      break
    end
    size = io.read(4).unpack('V').first
    out = depth > 0 ? '   ' * depth + id : id
    if id =~ /^(?:RIFF|LIST)$/
      lid = io.read(4)
      out << ' - ' + lid
      out << ' (%d)' % size
      puts out
      rifftree io, depth + 1, size
    else
      out << ' (%d)' % size
      puts out
      io.pos += size
      io.pos += 1 if size % 2 == 1
    end

  end
end

open(ARGV.shift, 'rb') do |io|
  rifftree io
end