Class: MiscHacks::Random

Inherits:
Object
  • Object
show all
Includes:
Singleton
Defined in:
lib/mischacks/random.rb

Instance Method Summary collapse

Constructor Details

#initialize ⇒ Random

Returns a new instance of Random.



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# File 'lib/mischacks/random.rb', line 24

def initialize
  @mutex = Mutex.new
  @pool = 0
  @pool_size = 0
end

Instance Method Details

#exp(size_bits) ⇒ Object

0 ≤ return_value < 2^size_bits



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# File 'lib/mischacks/random.rb', line 31

def exp size_bits
  @mutex.synchronize do
    while @pool_size < size_bits
      # Push 32×8 bits to the pool.
      SecureRandom.random_bytes(32).unpack('Q*').each do |byte|
        @pool = (@pool << 64) | byte
        @pool_size += 64
      end
    end

    # Unshift size_bits bits from the pool.
    @pool_size -= size_bits
    bits   = @pool >> @pool_size
    @pool ^= bits << @pool_size

    bits
  end
end

#float(n = 1) ⇒ Object 



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# File 'lib/mischacks/random.rb', line 50

def float n=1
  n*Math.ldexp(exp(Float::MANT_DIG), -Float::MANT_DIG)
end

#inspect ⇒ Object 



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# File 'lib/mischacks/random.rb', line 58

def inspect
  "#<#{self.class}: pool_size=#{@pool_size}>"
end

#int(n) ⇒ Object 



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# File 'lib/mischacks/random.rb', line 54

def int n
  float(n).floor
end