ass_crunch.rb

require 'ffi'

class ASS_Event < FFI::Struct
  layout :start, :long_long,
  :duration, :long_long,
  :readOrder, :int,
  :layer, :int,
  :style, :int,
  :name, :string,
  :marginL, :int,
  :marginR, :int,
  :marginV, :int,
  :effect, :string,
  :text, :string,
  :render_priv, :pointer
end

class ASS_Track < FFI::Struct
  layout :n_styles, :int,
  :max_styles, :int,
  :n_events, :int,
  :max_events, :int,
  :styles, :pointer,
  :events, :pointer
end

def cast_to_ass_track pointer
  ASS_Track.new pointer
end

def cast_to_ass_event pointer
  ASS_Event.new pointer
end

def get_event ass_track, num
  cast_to_ass_event ass_track[:events] + ASS_Event.size * num
end

module Ass
  extend FFI::Library
  ffi_lib ['ass']
  attach_function :ass_library_init, [], :pointer
  attach_function :ass_read_file, [:pointer, :string, :uint], :pointer
  attach_function :ass_free_track, [:pointer], :void
  attach_function :ass_library_done, [:pointer], :void
end

ass_library = Ass.ass_library_init
ptr = Ass.ass_read_file ass_library, './sao16.ass', 0
ass_track = cast_to_ass_track ptr

puts "Lines: #{ass_track[:n_events]}"
for i in 0..ass_track[:n_events] - 1
  puts (get_event ass_track, i)[:text]
end

Ass.ass_free_track ass_track
Ass.ass_library_done ass_library