.pak file format of Dune 2 game engine: Ruby parsing library

Application

Dune 2 game engine

File extension

pak

KS implementation details

License: CC0-1.0
Minimal Kaitai Struct required: 0.8

This page hosts a formal specification of .pak file format of Dune 2 game engine using Kaitai Struct. This specification can be automatically translated into a variety of programming languages to get a parsing library.

Usage

Runtime library

All parsing code for Ruby generated by Kaitai Struct depends on the Ruby runtime library. You have to install it before you can parse data.

The Ruby runtime library can be installed from RubyGems:

gem install kaitai-struct

Code

Parse a local file and get structure in memory:

data = Dune2Pak.from_file("path/to/local/file.pak")

Or parse structure from a string of bytes:

bytes = "\x00\x01\x02..."
data = Dune2Pak.new(Kaitai::Struct::Stream.new(bytes))

After that, one can get various attributes from the structure by invoking getter methods like:

data.dir # => get dir

Ruby source code to parse .pak file format of Dune 2 game engine

dune_2_pak.rb

# This is a generated file! Please edit source .ksy file and use kaitai-struct-compiler to rebuild

require 'kaitai/struct/struct'

unless Gem::Version.new(Kaitai::Struct::VERSION) >= Gem::Version.new('0.9')
  raise "Incompatible Kaitai Struct Ruby API: 0.9 or later is required, but you have #{Kaitai::Struct::VERSION}"
end


##
# @see http://www.shikadi.net/moddingwiki/PAK_Format_(Westwood) Source
class Dune2Pak < Kaitai::Struct::Struct
  def initialize(_io, _parent = nil, _root = self)
    super(_io, _parent, _root)
    _read
  end

  def _read
    @_raw_dir = @_io.read_bytes(dir_size)
    _io__raw_dir = Kaitai::Struct::Stream.new(@_raw_dir)
    @dir = Files.new(_io__raw_dir, self, @_root)
    self
  end
  class Files < Kaitai::Struct::Struct
    def initialize(_io, _parent = nil, _root = self)
      super(_io, _parent, _root)
      _read
    end

    def _read
      @files = []
      i = 0
      while not @_io.eof?
        @files << File.new(@_io, self, @_root, i)
        i += 1
      end
      self
    end
    attr_reader :files
  end
  class File < Kaitai::Struct::Struct
    def initialize(_io, _parent = nil, _root = self, idx)
      super(_io, _parent, _root)
      @idx = idx
      _read
    end

    def _read
      @ofs = @_io.read_u4le
      if ofs != 0
        @file_name = (@_io.read_bytes_term(0, false, true, true)).force_encoding("ASCII")
      end
      self
    end
    def next_ofs0
      return @next_ofs0 unless @next_ofs0.nil?
      if ofs != 0
        @next_ofs0 = _root.dir.files[(idx + 1)].ofs
      end
      @next_ofs0
    end
    def next_ofs
      return @next_ofs unless @next_ofs.nil?
      if ofs != 0
        @next_ofs = (next_ofs0 == 0 ? _root._io.size : next_ofs0)
      end
      @next_ofs
    end
    def body
      return @body unless @body.nil?
      if ofs != 0
        io = _root._io
        _pos = io.pos
        io.seek(ofs)
        @body = io.read_bytes((next_ofs - ofs))
        io.seek(_pos)
      end
      @body
    end
    attr_reader :ofs
    attr_reader :file_name
    attr_reader :idx
  end
  def dir_size
    return @dir_size unless @dir_size.nil?
    _pos = @_io.pos
    @_io.seek(0)
    @dir_size = @_io.read_u4le
    @_io.seek(_pos)
    @dir_size
  end
  attr_reader :dir
  attr_reader :_raw_dir
end