Class: Bignum

Inherits:
Object
  • Object
show all
Defined in:
lib/net/ber.rb

Instance Method Summary collapse

Instance Method Details

#to_ber ⇒ Object 



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# File 'lib/net/ber.rb', line 464

def to_ber
  #i = [self].pack('w')
  #i.length > 126 and raise Net::BER::BerError.new( "range error in bignum" )
  #[2, i.length].pack("CC") + i

  # Ruby represents Bignums as two's-complement numbers so we may actually be
  # good as far as representing negatives goes.
  # I'm sure this implementation can be improved performance-wise if necessary.
  # Ruby's Bignum#size returns the number of bytes in the internal representation
  # of the number, but it can and will include leading zero bytes on at least
  # some implementations. Evidently Ruby stores these as sets of quadbytes.
  # It's not illegal in BER to encode all of the leading zeroes but let's strip
  # them out anyway.
  #
  out = [0] * size    
  (size * 8).times do |bit|
    next unless self[bit] == 1
    out[bit/8] += (1 << (bit % 8))
  end
  out = out.pack('C*')
  out.slice!(-1,1) while out.length > 1 and Net::BER.ord(out[-1]).zero?
  [2, out.length].pack("CC") + out.reverse
end