Parse GZipped results

parse.rb

#!/usr/bin/env ruby
require 'active_support'

gzips = {
  :java => [31, -117, 8, 0, 0, 0, 0, 0, 0, 0, -77, 41, 74, 45, 44, 77, 45, 46, -79, -77, 41, -120, -49, 76, -79, 51, 50, 48, -78, -80, -47, 7, 51, 109, -118, -13, 75, -117, -110, 83, -29, 75, 42, 11, 82, -19, 12, 108, -12, -111, -71, 54, -6, 48, 109, 0, -21, -40, -25, -121, 64, 0, 0, 0],
  :ruby => [31, -117, 8, 0, 32, 45, 19, 80, 0, 3, -77, 41, 74, 45, 44, 77, 45, 46, -79, -77, 41, -120, -49, 76, -79, 51, 50, 48, -78, -80, -47, 7, 51, 109, -118, -13, 75, -117, -110, 83, -29, 75, 42, 11, 82, -19, 12, 108, -12, -111, -71, 54, -6, 48, 109, 0, -21, -40, -25, -121, 64, 0, 0, 0],
}

def formatted_put(text, comment)
  text = text.join(' ') if text.is_a? Array
  text = text.to_s unless text.is_a? String
  puts "#{text}#{' ' * (20 - text.length)} # #{comment}"
end

gzips.each do |lang, gz|
  puts "*" * 30
  puts lang
  # magic header
  arr = gz.shift(2)
  raise "ERROR: magic header incorrect #{arr.inspect}" unless arr == [31, -117]
  formatted_put(arr.join(' '), "magic header")

  # compression method
  arr = gz.shift
  raise "ERROR: Invalid compression method #{arr}" unless (0..8).include?(arr)
  method = case arr
           when 0      then "store (copied)"
           when 1      then "compress"
           when 2      then "pack"
           when 3      then "lzh"
           when (4..7) then "reserved"
           when 8      then "deflate"
           end
  formatted_put(arr, "Compression method: #{method}")

  # flags
  arr = gz.shift
  formatted_put(arr, "Flag: something?")

  arr = gz.shift(4)
  time = (arr[3] << 24) + (arr[2] << 16) + (arr[1] << 8) + arr[0]
  formatted_put(arr.join(' '), "File mod. time = #{Time.at(time).to_s}")

  arr = gz.shift
  formatted_put(arr, "Extra flags")

  arr = gz.shift
  os = case arr
       when  0 then "FAT filesystem (MS-DOS, OS/2, NT/Win32)"
       when  1 then "Amiga"
       when  2 then "VMS (or OpenVMS)"
       when  3 then "Unix"
       when  4 then "VM/CMS"
       when  5 then "Atari TOS"
       when  6 then "HPFS filesystem (OS/2, NT)"
       when  7 then "Macintosh"
       when  8 then "Z-System"
       when  9 then "CP/M"
       when 10 then "TOPS-20"
       when 11 then "NTFS filesystem (NT)"
       when 12 then "QDOS"
       when 13 then "Acorn RISCOS"
       when 15 then "unknown"
       end
  formatted_put(arr, "OS: #{os}")
end

=begin
$ ./parse.rb
******************************
java
31 -117              # magic header
8                    # Compression method: deflate
0                    # Flag: something?
0 0 0 0              # File mod. time = 1969-12-31 16:00:00 -0800
0                    # Extra flags
0                    # OS: FAT filesystem (MS-DOS, OS/2, NT/Win32)
******************************
ruby
31 -117              # magic header
8                    # Compression method: deflate
0                    # Flag: something?
32 45 19 80          # File mod. time = 2012-07-27 17:06:56 -0700
0                    # Extra flags
3                    # OS: Unix
=end