Module: XBee::Frame

Defined in:
lib/apimode/frame/frame.rb,
lib/apimode/frame/at_command.rb,
lib/apimode/frame/modem_status.rb,
lib/apimode/frame/receive_packet.rb,
lib/apimode/frame/transmit_status.rb,
lib/apimode/frame/transmit_request.rb,
lib/apimode/frame/at_command_response.rb,
lib/apimode/frame/explicit_rx_indicator.rb,
lib/apimode/frame/remote_command_request.rb,
lib/apimode/frame/remote_command_response.rb,
lib/apimode/frame/explicit_addressing_command.rb

Defined Under Namespace

Classes: ATCommand, ATCommandQueueParameterValue, ATCommandResponse, Base, ExplicitAddressingCommand, ExplicitRxIndicator, ModemStatus, ReceivePacket, ReceivedFrame, RemoteCommandRequest, RemoteCommandResponse, TransmitRequest, TransmitStatus

Class Method Summary collapse

Class Method Details

.checksum(data) ⇒ Object 



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# File 'lib/apimode/frame/frame.rb', line 14

def Frame.checksum(data)
  0xFF - (data.unpack("C*").inject(0) { |sum, byte| (sum + byte) & 0xFF })
end

.new(source_io) ⇒ Object 



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# File 'lib/apimode/frame/frame.rb', line 18

def Frame.new(source_io)
  stray_bytes = []
  until (start_delimiter = source_io.readchar.unpack('H*').join.to_i(16)) == 0x7e
    #puts "Stray byte 0x%x" % start_delimiter
    print "DEBUG: #{start_delimiter} | " if $DEBUG
    stray_bytes << start_delimiter
  end
  puts "Got some stray bytes for ya: #{stray_bytes.map {|b| "0x%x" % b} .join(", ")}" unless stray_bytes.empty?
  header = source_io.read(3).xb_unescape
  print "Reading ... header after start byte: #{header.unpack("C*").join(", ")} | " if $DEBUG
  frame_remaining = frame_length = api_identifier = cmd_data = ""
  if header.length == 3
    frame_length, api_identifier = header.unpack("nC")
  else
    frame_length, api_identifier = header.unpack("n").first, source_io.readchar
  end
  #### DEBUG ####
  if $DEBUG then
  print "Frame length: #{frame_length} | "
  print "Api Identifier: #{api_identifier} | "
  end
  #### DEBUG ####
  cmd_data_intended_length = frame_length - 1
  while ((unescaped_length = cmd_data.xb_unescape.length) < cmd_data_intended_length)
    cmd_data += source_io.read(cmd_data_intended_length - unescaped_length)
  end
  data = api_identifier.chr + cmd_data.xb_unescape
  sent_checksum = source_io.getc.unpack('H*').join.to_i(16)
  #### DEBUG ####
  if $DEBUG then
  print "Sent checksum: #{sent_checksum} | "
  print "Received checksum: #{Frame.checksum(data)} | "
  print "Payload: #{cmd_data.unpack("C*").join(", ")} | "
  end
  #### DEBUG ####
  unless sent_checksum == Frame.checksum(data)
    raise "Bad checksum - data discarded"
  end
  case data[0].unpack('H*')[0].to_i(16)
    when 0x8A
      ModemStatus.new(data)
    when 0x88 
      ATCommandResponse.new(data)
    when 0x97 
      RemoteCommandResponse.new(data)
    when 0x8B 
      TransmitStatus.new(data)
    when 0x90 
      ReceivePacket.new(data)
    when 0x91 
      ExplicitRxIndicator.new(data)
    when 0x92
      IODataSampleRxIndicator.new(data)
    else
      ReceivedFrame.new(data)
  end
  rescue EOFError
    # No operation as we expect eventually something
end