.dat file format of Faster Than Light (FTL): Ruby parsing library

Application

Faster Than Light (FTL)

File extension

dat

KS implementation details

License: CC0-1.0

This page hosts a formal specification of .dat file format of Faster Than Light (FTL) 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 = FtlDat.from_file("path/to/local/file.dat")

Or parse structure from a string of bytes:

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

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

data.num_files # => Number of files in the archive

Ruby source code to parse .dat file format of Faster Than Light (FTL)

ftl_dat.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

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

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

    def _read
      @ofs_meta = @_io.read_u4le
      self
    end
    def meta
      return @meta unless @meta.nil?
      if ofs_meta != 0
        _pos = @_io.pos
        @_io.seek(ofs_meta)
        @meta = Meta.new(@_io, self, @_root)
        @_io.seek(_pos)
      end
      @meta
    end
    attr_reader :ofs_meta
  end
  class Meta < Kaitai::Struct::Struct
    def initialize(_io, _parent = nil, _root = self)
      super(_io, _parent, _root)
      _read
    end

    def _read
      @len_file = @_io.read_u4le
      @len_filename = @_io.read_u4le
      @filename = (@_io.read_bytes(len_filename)).force_encoding("UTF-8")
      @body = @_io.read_bytes(len_file)
      self
    end
    attr_reader :len_file
    attr_reader :len_filename
    attr_reader :filename
    attr_reader :body
  end

  ##
  # Number of files in the archive
  attr_reader :num_files
  attr_reader :files
end