Module: NickelSilver::Server::Interface

Defined in:

lib/nickel-silver-server.rb,
lib/LocoBufferUSB.rb

Overview

An interface class should provide the following:

• Store incoming packets as FixNums representing bytes in a buffer array

• Send outgoing bytes (represented as FixNums in a buffer array) to LocoNet

• Use a Mutex to lock access to the buffers when in use (remember Nickel-Silver is multithreaded)

• Provide a method that causes your interface to start collecting packets

The interface is simple. Only the following public methods are needed:

• Accessors for input_buffer, output_buffer and io_mutex

• run() which starts buffering

How you do this will depend upon your hardware. Take a look at the LocoBufferUSB class to get an idea of how it might be done.

A stub driver might look like the following…

class SomeLocoNetInterface
  attr_accessor :input_buffer, :output_buffer, :io_mutex

  def initialize
    # these may be modified at any time by the server
    @input_buffer = []
    @output_buffer = []

    # only make changes when locked using @io_mutex
    @io_mutex = Mutex.new
  end

  def run
    loop do
      # get incoming bytes
      if byte_waiting?
        @io_mutex.synchronize do
          # byte getting code here
          @input_buffer << get_byte
        end
      end

      # send outgoing bytes
      until @output_buffer.empty? do
        @io_mutex.synchronize do
          # send a byte
          send_byte( @output_buffer.shift )
        end
      end
    end
  end

end

Defined Under Namespace

Classes: LocoBufferUSB