Class: Mikrotik::Protocol::Parser

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

Overview

Responsible for extracting replies from API sentence data

Constant Summary

PAIR =
/^(.+)=(.+)$/

Instance Method Summary (collapse)

Constructor Details

- (Parser) initialize



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# File 'lib/mikrotik/protocol/parser.rb', line 9

def initialize
  @data = ''
  @data.force_encoding(Encoding::BINARY) if RUBY_VERSION > '1.9'
  reset!
end

Instance Method Details

- (Object) <<(data)

Adds data to the parser buffer and runs the parser



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# File 'lib/mikrotik/protocol/parser.rb', line 21

def <<(data)
  @data << data
  success = true
  success = get_sentence while success
end

- (Object) bytes(bits)



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# File 'lib/mikrotik/protocol/parser.rb', line 122

def bytes(bits)
  (bits / 8.0).ceil
end

- (Object) get_length



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# File 'lib/mikrotik/protocol/parser.rb', line 54

def get_length
  size = get_length_size

  return false unless size

  need = bytes(size + 1)
  return false unless @data.size >= need

  length = nil
  field = @data[0, need].unpack('C*')

  case size
    when 7
      length = field[0] & 0x7f
    when 14
      length = ((field[0] & 0x3f) <<  8) | field[1]
    when 21
      length = ((field[0] & 0x1f) << 16) | field[1] <<  8 | field[2]
    when 28
      length = ((field[0] & 0x0f) << 24) | field[1] << 16 | field[2] << 8 | field[3]
    when 32
      length = field[1..4].pack('C4').unpack('N').first
  end

  if length
    return length
  else
    raise ArgumentError, "Invalid word length"
  end
end

- (Object) get_length_size

Indentifies the size of the length field in bits

Raises:

  • (ArgumentError)


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# File 'lib/mikrotik/protocol/parser.rb', line 31

def get_length_size
  return false if @data.empty?

  # High bits used for length type
  # Low bits used as first bits of length
  
  # 0xxxxxxx = 7  bit length
  # 10xxxxxx = 14 bit length
  # 110xxxxx = 21 bit length
  # 1110xxxx = 28 bit length
  # 11110000 = 32 bit length follows

  t = @data.unpack('C').first

  return  7 if t &  0b10000000 == 0
  return 14 if t &  0b01000000 == 0
  return 21 if t &  0b00100000 == 0
  return 28 if t &  0b00010000 == 0
  return 32 if t == 0b11110000

  raise ArgumentError, "Invalid length type encoding"
end

- (Object) get_sentence



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# File 'lib/mikrotik/protocol/parser.rb', line 102

def get_sentence
  while word = get_word 
    if word.empty?
      Mikrotik.debug [:parser, :got_sentence, @sentence]
      on_sentence(@sentence)
      reset!
      return true
    else
      if word =~ PAIR
        key, value = word.scan(PAIR).flatten
        @sentence[key] = value
      else
        @sentence[word] = nil
      end
    end
  end

  return false
end

- (Object) get_word



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# File 'lib/mikrotik/protocol/parser.rb', line 85

def get_word
  return false if @data.empty?
  length_size = bytes(get_length_size + 1)
  length      = get_length
  
  total_size  = length_size + length
  
  if length && @data.size >= total_size
    @data.slice!(0, length_size)
    word = @data.slice!(0, length)
    Mikrotik.debug [:parser, :got_word, word]
    return word
  end

  return false
end

- (Object) reset!

Discards the sentence currently being parsed



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# File 'lib/mikrotik/protocol/parser.rb', line 16

def reset!
  @sentence = Mikrotik::Protocol::Sentence.new
end