Class: Nibbler::Parser

Inherits:
Object
  • Object
show all
Defined in:
lib/nibbler/parser.rb

Defined Under Namespace

Classes: RunningStatus

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(library) ⇒ Parser

Returns a new instance of Parser.



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# File 'lib/nibbler/parser.rb', line 7

def initialize(library)
  @library = library
  @running_status = RunningStatus.new
  @buffer = []
end

Instance Attribute Details

#buffer ⇒ Object (readonly)

Returns the value of attribute buffer.



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# File 'lib/nibbler/parser.rb', line 5

def buffer
  @buffer
end

Instance Method Details

#nibbles_to_message(fragment) ⇒ Hash?

If possible, convert the given fragment to a MIDI message

Parameters:

  • fragment (Array<String>) —

    A fragment of data eg [“9”, “0”, “4”, “0”, “5”, “0”]

Returns:

  • (Hash, nil) 


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# File 'lib/nibbler/parser.rb', line 49

def nibbles_to_message(fragment)
  if fragment.length >= 2
    # convert the part of the fragment to start with to a numeric
    slice = fragment.slice(0..1).map(&:hex)
    compute_message(slice, fragment)
  end
end

#process(nibbles) ⇒ Hash

Process the given nibbles and add them to the buffer

Parameters:

  • nibbles (Array<String, Integer>)

Returns:

  • (Hash) 


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# File 'lib/nibbler/parser.rb', line 16

def process(nibbles)
  report = {
    :messages => [],
    :processed => [],
    :rejected => []
  }
  pointer = 0
  @buffer += nibbles
  # Iterate through nibbles in the buffer until a status message is found
  while pointer <= (@buffer.length - 1)
    # fragment is the piece of the buffer to look at
    fragment = get_fragment(pointer)
    # See if there really is a message there
    unless (processed = nibbles_to_message(fragment)).nil?
      # if fragment contains a real message, reject the nibbles that precede it
      report[:rejected] += @buffer.slice(0, pointer)
      # and record it
      @buffer = fragment.dup # fragment now has the remaining nibbles for next pass
      fragment = nil # Reset fragment
      pointer = 0 # Reset iterator
      report[:messages] << processed[:message]
      report[:processed] += processed[:processed]
    else
      @running_status.cancel
      pointer += 1
    end
  end
  report
end