Class: Dcha::MPT::NibbleKey

Inherits:
Array
  • Object
show all
Defined in:
lib/dcha/mpt/nibble_key.rb

Overview

:nodoc:

Constant Summary collapse

TERM_FLAG = 
0b0010
ODD_FLAG = 
0b0001
TERMINATOR = 
16
HEX_VALUES = 
Hash[(0..15).map { |i| [i.to_s(16), i]

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.decode(bytes) ⇒ Object 



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# File 'lib/dcha/mpt/nibble_key.rb', line 26

def decode(bytes)
  o = from_string bytes
  flags = o[0]

  o.push TERMINATOR if flags & TERM_FLAG > 0
  fill = flags & ODD_FLAG > 0 ? 1 : 2
  new o[fill..-1]
end

.encode(nibbles) ⇒ Object 



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# File 'lib/dcha/mpt/nibble_key.rb', line 12

def encode(nibbles)
  flags = 0

  if nibbles.last == TERMINATOR
    flags |= TERM_FLAG
    nibbles = nibbles[0...-1]
  end

  odd = nibbles.size % 2
  flags |= odd
  return pack [flags] + nibbles if odd == 1
  pack [flags, 0b0000] + nibbles
end

.from_string(s) ⇒ Object 



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# File 'lib/dcha/mpt/nibble_key.rb', line 35

def from_string(s)
  nibbles = s.unpack('H*')
             .first
             .each_char
             .map { |c| HEX_VALUES[c] }
  new nibbles
end

.terminator ⇒ Object 



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# File 'lib/dcha/mpt/nibble_key.rb', line 51

def terminator
  new [TERMINATOR]
end

.to_string(nibbles) ⇒ Object

Raises:

  • (ArgumentError) 


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# File 'lib/dcha/mpt/nibble_key.rb', line 43

def to_string(nibbles)
  # TODO: Add error message
  raise ArgumentError unless nibbles.any? { |x| x.between?(0, 15) }
  raise ArgumentError if nibbles.size.odd?

  pack nibbles
end

Instance Method Details

#+(other) ⇒ Object 



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# File 'lib/dcha/mpt/nibble_key.rb', line 105

def +(other)
  self.class.new super(other)
end

#common_prefix(another_key) ⇒ Object 



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# File 'lib/dcha/mpt/nibble_key.rb', line 85

def common_prefix(another_key)
  prefix = []

  [size, another_key.size].min.times do |i|
    break if self[i] != another_key[i]
    prefix.push self[i]
  end

  self.class.new prefix
end

#encode ⇒ Object 



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# File 'lib/dcha/mpt/nibble_key.rb', line 96

def encode
  self.class.encode self
end

#prefix?(another_key) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/dcha/mpt/nibble_key.rb', line 80

def prefix?(another_key)
  return false if another_key.size < size
  another_key.take(size) == self
end

#terminate(flag) ⇒ Object 



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# File 'lib/dcha/mpt/nibble_key.rb', line 70

def terminate(flag)
  dup.tap do |copy|
    if flag
      copy.push TERMINATOR unless copy.terminate?
    elsif copy.terminate?
      copy.pop
    end
  end
end

#terminate? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/dcha/mpt/nibble_key.rb', line 66

def terminate?
  last == TERMINATOR
end

#to_s ⇒ Object Also known as: to_string 



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# File 'lib/dcha/mpt/nibble_key.rb', line 100

def to_s
  self.class.to_string self
end