http://w3g.deepnode.de/files/w3g_format.txt http://blog.csdn.net/xiao__gui/article/details/17993589

w3g.rb

require 'bindata'

module W3G
  # 68 bytes
  class ReplayHeader < BinData::Record
    endian :little

    string :id_string, :read_length => 28
    uint32 :header_size
    uint32 :compressed_size
    uint32 :header_version
    uint32 :decompressed_size
    uint32 :block_count

    string :version_string, :length => 4
    uint32 :version_number
    uint16 :build_number
    uint16 :game_mode
    uint32 :replay_duration
    uint32 :checksum
  end

  class CompressedDataBlock < BinData::Record
    endian :little

    # 8 bytes header
    uint16 :compressed_size
    uint16 :decompressed_size
    uint32 :unknown

    string :data, :read_length => :compressed_size
  end

  class Replay < BinData::Record
    replay_header :header
    array :blocks, :type => :compressed_data_block,
                   :initial_length => lambda { header.block_count }
  end

end

f = File.new "rep1.w3g", 'rb'

replay = W3G::Replay.read f

#p replay.header.block_count
#p replay.blocks.size

p "    header size: #{replay.header_size}"
p "compressed size: #{replay.compressed_size}"
p 
p f.eof?