Method: Rex::RandomIdentifierGenerator#initialize

Defined in:
lib/rex/random_identifier_generator.rb

#initialize(opts = {}) ⇒ RandomIdentifierGenerator

Returns a new instance of RandomIdentifierGenerator.

Parameters:

  • opts (Hash) (defaults to: {}) —

    Options, see DefaultOpts for default values

Options Hash (opts):

  • :max_length (Fixnum)
  • :min_length (Fixnum)
  • :char_set (String) 


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# File 'lib/rex/random_identifier_generator.rb', line 42

def initialize(opts={})
  # Holds all identifiers.
  @value_by_name = {}
  # Inverse of value_by_name so we can ensure uniqueness without
  # having to search through the whole list of values
  @name_by_value = {}

  @opts = DefaultOpts.merge(opts)
  if @opts[:min_length] < 1 || @opts[:max_length] < 1 || @opts[:max_length] < @opts[:min_length]
    raise ArgumentError, "Invalid length options"
  end

  # This is really just the maximum number of shortest names. This
  # will still be a pretty big number most of the time, so don't
  # bother calculating the real one, which will potentially be
  # expensive, since we're talking about a 36-digit decimal number to
  # represent the total possibilities for the range of 10- to
  # 20-character identifiers.
  #
  # 26 because the first char is lowercase alpha, (min_length - 1) and
  # not just min_length because it includes that first alpha char.
  @max_permutations = 26 * (@opts[:char_set].length ** (@opts[:min_length]-1))
  # The real number of permutations could be calculated thusly:
  #((@opts[:min_length]-1) .. (@opts[:max_length]-1)).reduce(0) { |a, e|
  #	a + (26 * @opts[:char_set].length ** e)
  #}
end