Class: PCO::URL::Encryption::Chunk

Inherits:
Object
  • Object
show all
Defined in:
lib/pco/url/encryption.rb

Instance Method Summary collapse

Constructor Details

#initialize(bytes) ⇒ Chunk

Returns a new instance of Chunk.



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# File 'lib/pco/url/encryption.rb', line 38

def initialize(bytes)
  @bytes = bytes
end

Instance Method Details

#decode ⇒ Object

rubocop:disable Metrics/AbcSize



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# File 'lib/pco/url/encryption.rb', line 42

def decode # rubocop:disable Metrics/AbcSize
  bytes = @bytes.take_while { |c| c != 61 } # strip padding
  bytes = bytes.find_all { |b| !TABLE.index(b.chr).nil? } # remove invalid characters
  n = (bytes.length * 5.0 / 8.0).floor
  p = bytes.length < 8 ? 5 - (n * 8) % 5 : 0
  c = bytes.inject(0) { |m, o| (m << 5) + TABLE.index(o.chr) } >> p
  (0..(n - 1)).to_a.reverse.collect { |i| ((c >> i * 8) & 0xff).chr }
end

#encode ⇒ Object

rubocop:disable Metrics/AbcSize



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# File 'lib/pco/url/encryption.rb', line 51

def encode # rubocop:disable Metrics/AbcSize
  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
  [
    (0..(n - 1)).to_a.reverse.collect { |i| TABLE[(c >> i * 5) & 0x1f].chr },
    ("=" * (8 - n))
  ]
end