Class: Multibases::Base32::Chunk

Inherits:
Object
  • Object
show all
Defined in:
lib/multibases/base32.rb

Instance Method Summary collapse

Constructor Details

#initialize(bytes, table) ⇒ Chunk

Returns a new instance of Chunk.



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# File 'lib/multibases/base32.rb', line 49

def initialize(bytes, table)
  @bytes = bytes
  @table = table
end

Instance Method Details

#decode ⇒ Object 



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# File 'lib/multibases/base32.rb', line 54

def decode
  bytes = @bytes.take_while { |c| c != @table.padder }

  n = (bytes.length * 5.0 / 8.0).floor
  p = bytes.length < 8 ? 5 - (n * 8) % 5 : 0

  c = bytes.inject(0) do |m, o|
    i = @table.index(o)
    raise ArgumentError, "Invalid character '#{[o].pack('C*')}'" if i.nil?

    (m << 5) + i
  end >> p

  (0..(n - 1)).to_a.reverse.collect { |i| ((c >> i * 8) & 0xff) }
end

#encode ⇒ Object 



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# File 'lib/multibases/base32.rb', line 70

def encode
  n = (@bytes.length * 8.0 / 5.0).ceil
  p = n < 8 ? 5 - (@bytes.length * 8) % 5 : 0
  c = @bytes.inject(0) { |m, o| (m << 8) + o } << p

  output = (0..(n - 1)).to_a.reverse.collect do |i|
    @table.ord_at((c >> i * 5) & 0x1f)
  end
  @table.padder ? output + Array.new((8 - n), @table.padder) : output
end