fallout2_dat: Ruby parsing library

Application

Fallout 2

KS implementation details

License: CC0-1.0

References

This page hosts a formal specification of fallout2_dat 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 = Fallout2Dat.from_file("path/to/local/file.fallout2_dat")

Or parse structure from a string of bytes:

bytes = "\x00\x01\x02..."
data = Fallout2Dat.new(Kaitai::Struct::Stream.new(bytes))

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

data.footer # => get footer

Ruby source code to parse fallout2_dat

fallout2_dat.rb

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

require 'kaitai/struct/struct'
require 'zlib'

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

class Fallout2Dat < Kaitai::Struct::Struct

  COMPRESSION = {
    0 => :compression_none,
    1 => :compression_zlib,
  }
  I__COMPRESSION = COMPRESSION.invert
  def initialize(_io, _parent = nil, _root = self)
    super(_io, _parent, _root)
    _read
  end

  def _read
    self
  end
  class Pstr < Kaitai::Struct::Struct
    def initialize(_io, _parent = nil, _root = self)
      super(_io, _parent, _root)
      _read
    end

    def _read
      @size = @_io.read_u4le
      @str = (@_io.read_bytes(size)).force_encoding("ASCII")
      self
    end
    attr_reader :size
    attr_reader :str
  end
  class Footer < Kaitai::Struct::Struct
    def initialize(_io, _parent = nil, _root = self)
      super(_io, _parent, _root)
      _read
    end

    def _read
      @index_size = @_io.read_u4le
      @file_size = @_io.read_u4le
      self
    end
    attr_reader :index_size
    attr_reader :file_size
  end
  class Index < Kaitai::Struct::Struct
    def initialize(_io, _parent = nil, _root = self)
      super(_io, _parent, _root)
      _read
    end

    def _read
      @file_count = @_io.read_u4le
      @files = Array.new(file_count)
      (file_count).times { |i|
        @files[i] = File.new(@_io, self, @_root)
      }
      self
    end
    attr_reader :file_count
    attr_reader :files
  end
  class File < Kaitai::Struct::Struct
    def initialize(_io, _parent = nil, _root = self)
      super(_io, _parent, _root)
      _read
    end

    def _read
      @name = Pstr.new(@_io, self, @_root)
      @flags = Kaitai::Struct::Stream::resolve_enum(Fallout2Dat::COMPRESSION, @_io.read_u1)
      @size_unpacked = @_io.read_u4le
      @size_packed = @_io.read_u4le
      @offset = @_io.read_u4le
      self
    end
    def contents_raw
      return @contents_raw unless @contents_raw.nil?
      if flags == :compression_none
        io = _root._io
        _pos = io.pos
        io.seek(offset)
        @contents_raw = io.read_bytes(size_unpacked)
        io.seek(_pos)
      end
      @contents_raw
    end
    def contents_zlib
      return @contents_zlib unless @contents_zlib.nil?
      if flags == :compression_zlib
        io = _root._io
        _pos = io.pos
        io.seek(offset)
        @_raw_contents_zlib = io.read_bytes(size_packed)
        @contents_zlib = Zlib::Inflate.inflate(@_raw_contents_zlib)
        io.seek(_pos)
      end
      @contents_zlib
    end
    def contents
      return @contents unless @contents.nil?
      if  ((flags == :compression_zlib) || (flags == :compression_none)) 
        @contents = (flags == :compression_zlib ? contents_zlib : contents_raw)
      end
      @contents
    end
    attr_reader :name
    attr_reader :flags
    attr_reader :size_unpacked
    attr_reader :size_packed
    attr_reader :offset
    attr_reader :_raw_contents_zlib
  end
  def footer
    return @footer unless @footer.nil?
    _pos = @_io.pos
    @_io.seek((_io.size - 8))
    @footer = Footer.new(@_io, self, @_root)
    @_io.seek(_pos)
    @footer
  end
  def index
    return @index unless @index.nil?
    _pos = @_io.pos
    @_io.seek(((_io.size - 8) - footer.index_size))
    @index = Index.new(@_io, self, @_root)
    @_io.seek(_pos)
    @index
  end
end