koraktor/steam-condenser-ruby

# This code is free software; you can redistribute it and/or modify it under
# the terms of the new BSD License.
#
# Copyright (c) 2008-2013, Sebastian Staudt

require 'core_ext/stringio'
require 'steam-condenser/error/timeout'
require 'steam-condenser/servers/sockets/base_socket'

module SteamCondenser::Servers::Sockets

  # This class represents a socket used to communicate with game servers based
  # on the Source engine (e.g. Team Fortress 2, Counter-Strike: Source)
  #
  # @author Sebastian Staudt
  class SourceSocket

    include BaseSocket
    include SteamCondenser::Logging

    # Reads a packet from the socket
    #
    # The Source query protocol specifies a maximum packet size of 1,400 bytes.
    # Bigger packets will be split over several UDP packets. This method
    # reassembles split packets into single packet objects. Additionally Source
    # may compress big packets using bzip2. Those packets will be compressed.
    #
    # @return [BasePacket] The packet replied from the server
    def reply
      receive_packet 1400
      is_compressed = false
      packet_checksum = 0

      if @buffer.long == 0xFFFFFFFE
        split_packets = []
        begin
          request_id = @buffer.long
          is_compressed = ((request_id & 0x80000000) != 0)
          packet_count = @buffer.getbyte
          packet_number = @buffer.getbyte + 1

          if is_compressed
            @buffer.long
            packet_checksum = @buffer.long
          else
            @buffer.short
          end

          split_packets[packet_number - 1] = @buffer.get

          log.debug "Received packet #{packet_number} of #{packet_count} for request ##{request_id}"

          bytes_read = 0
          if split_packets.size < packet_count
            begin
              bytes_read = receive_packet
            rescue SteamCondenser::Error::Timeout
            end
          end
        end while bytes_read > 0 && @buffer.long == 0xFFFFFFFE

        packet = SteamCondenser::Servers::Packets::SteamPacketFactory.reassemble_packet(split_packets, is_compressed, packet_checksum)
      else
        packet = SteamCondenser::Servers::Packets::SteamPacketFactory.packet_from_data(@buffer.get)
      end

      if log.debug?
        packet_class = packet.class.name[/[^:]*\z/]
        if is_compressed
          log.debug "Got compressed reply of type \"#{packet_class}\"."
        else
          log.debug "Got reply of type \"#{packet_class}\"."
        end
      end

      packet
    end

  end
end