Extracts files from Artemis Engine resource files (.psf).

artemis_extract.rb

#!/usr/bin/env ruby
# encoding: utf-8
# fronze_string_literal: true

##
# Extracts files from Artemis Engine resource files (.psf).
#
# Tested on:
# - Memory's Dogma CODE:01


require 'fileutils'

unless ARGV.length == 2
  puts "Incorrect arguments."
  puts "Usage: artemis_extract.rb <input_file_name> <output_directory_name>"
  exit 2
end
input_file_name = ARGV[0]
output_directory_name = ARGV[1]

input_file = File.open(input_file_name, 'rb')

# Convert little endian binary string to long int
def long_int(bstr)
  bstr.bytes.reverse.inject(0) {|m, c| m * 256 + c }
end

unless input_file.read(3) == "pf6"
  puts "Incorrect file signature."
  exit 1
end

info_size = long_int(input_file.read(4))
puts "Info size: #{info_size}"
file_count = long_int(input_file.read(4))
puts "File count: #{file_count}"

FileInfo = Struct.new :name, :offset, :size
file_list = []

file_count.times do |i|
  name_size = long_int(input_file.read(4))
  name = input_file.read(name_size).force_encoding('UTF-8')
  if !name.valid_encoding?
    name = name.force_encoding('SJIS')
    if !name.valid_encoding?
      raise 'Invalid encoding of file'
    end
    name = name.encode('UTF-8')
  end
  name = name.gsub('\\', File::SEPARATOR)
  puts "#{i + 1}: #{name}"

  input_file.seek(4, :CUR)
  offset = long_int(input_file.read(4))
  size = long_int(input_file.read(4))
  file_list << FileInfo.new(name, offset, size)
end

puts '======== Extracting ========'

file_list.each_with_index do |file, i|
  puts "#{i + 1}: #{file.name}"
  FileUtils.mkdir_p(File.expand_path(File.dirname(file.name), output_directory_name))
  input_file.seek(file.offset)
  File.write(File.expand_path(file.name, output_directory_name), input_file.read(file.size))
end

input_file.close
puts 'Done!'