Class: Bloomer::Scalable

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

Overview

Automatically expanding bloom filter. See gsd.di.uminho.pt/members/cbm/ps/dbloom.pdf

Constant Summary collapse

S = 
2
R = 
Math.log(2) ** 2

Instance Method Summary collapse

Constructor Details

#initialize(initial_capacity = 256, false_positive_probability = 0.001) ⇒ Scalable

Returns a new instance of Scalable.



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# File 'lib/bloomer.rb', line 66

def initialize(initial_capacity = 256, false_positive_probability = 0.001)
  @false_positive_probability = false_positive_probability
  @bloomers = [Bloomer.new(initial_capacity, false_positive_probability * R)]
end

Instance Method Details

#add(string) ⇒ Object 



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# File 'lib/bloomer.rb', line 79

def add string
  l = @bloomers.last
  r = l.add(string)
  if r && (l.count > l.capacity)
    @bloomers << Bloomer.new(l.capacity * S, @false_positive_probability * (R**@bloomers.size))
  end
  r
end

#capacity ⇒ Object 



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# File 'lib/bloomer.rb', line 71

def capacity
  @bloomers.last.capacity
end

#count ⇒ Object 



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# File 'lib/bloomer.rb', line 75

def count
  @bloomers.inject(0) {|i,b|i + b.count}
end

#include?(string) ⇒ Boolean

only return false if no bloomers include string.

Returns:

  • (Boolean) 


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# File 'lib/bloomer.rb', line 89

def include? string
  @bloomers.any? { |ea| ea.include? string }
end