Class: BloomFilter::BitVector

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

Constant Summary collapse

IS_RUBY_19 = 
RUBY_VERSION >= '1.9'

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(bits, from_str = nil) ⇒ BitVector

Returns a new instance of BitVector.



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# File 'lib/bloom_filter/bit_vector.rb', line 6

def initialize(bits, from_str = nil)
  @bytes = Array.new((bits.to_f / 8).ceil, 0)
  @size = bits
  
  if from_str
    from_str.size.times do |i|
      @bytes[i] = IS_RUBY_19 ? from_str[i].ord : from_str[i]
    end
  end
end

Instance Attribute Details

#size ⇒ Object (readonly)

Returns the value of attribute size.



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# File 'lib/bloom_filter/bit_vector.rb', line 3

def size
  @size
end

Instance Method Details

#[](index) ⇒ Object 



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# File 'lib/bloom_filter/bit_vector.rb', line 17

def [](index)
  (@bytes[index.to_i / 8] >> (index % 8)) & 0b1
end

#[]=(index, value) ⇒ Object 



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# File 'lib/bloom_filter/bit_vector.rb', line 21

def []=(index, value)
  new_value = value && value != 0 ? 1 : 0
  current_value = self[index]
  if current_value != new_value
    if new_value == 0
      @bytes[index.to_i / 8] -= 1 << (index % 8)
    else
      @bytes[index.to_i / 8] += 1 << (index % 8)
    end
  end
end

#eql?(o) ⇒ Boolean Also known as: ==

Returns:

  • (Boolean) 


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# File 'lib/bloom_filter/bit_vector.rb', line 39

def eql?(o)
  return false unless o.size == self.size
  self.size.times do |i|
    return false unless self[i] == o[i]
  end
  true
end

#to_s ⇒ Object 



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# File 'lib/bloom_filter/bit_vector.rb', line 33

def to_s
  str = ""
  @bytes.each { |byte| str << byte.chr }
  str
end