Class: Random

Inherits:
Object show all
Defined in:
opal/opal/corelib/random.rb,
opal/opal/corelib/random/seedrandom.js.rb,
opal/opal/corelib/random/math_random.js.rb,
opal/opal/corelib/random/mersenne_twister.js.rb

Constant Summary collapse

SEEDRANDOM_GENERATOR = 
`{
  new_seed: function() { return Math.abs($seed_generator.int32()); },
  reseed: function(seed) { return new seedrandom(seed); },
  rand: function($rng) { return $rng.quick(); }
}`
MATH_RANDOM_GENERATOR = 
`{
  new_seed: function() { return 0; },
  reseed: function(seed) { return {}; },
  rand: function($rng) { return Math.random(); }
}`
MERSENNE_TWISTER_GENERATOR = 
`{
  new_seed: function() { return Math.round(Math.random() * MAX_INT); },
  reseed: function(seed) { return MersenneTwister.init(seed); },
  rand: function(mt) { return MersenneTwister.genrand_real(mt); }
}`

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(seed = Random.new_seed) ⇒ Random

Returns a new instance of Random.



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# File 'opal/opal/corelib/random.rb', line 4

def initialize(seed = Random.new_seed)
  seed = Opal.coerce_to!(seed, Integer, :to_int)
  @state = seed
  reseed(seed)
end

Instance Attribute Details

#seed ⇒ Object (readonly)

Returns the value of attribute seed.



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# File 'opal/opal/corelib/random.rb', line 2

def seed
  @seed
end

#state ⇒ Object (readonly)

Returns the value of attribute state.



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# File 'opal/opal/corelib/random.rb', line 2

def state
  @state
end

Class Method Details

.generator=(generator) ⇒ Object 



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# File 'opal/opal/corelib/random.rb', line 116

def self.generator=(generator)
  `Opal.$$rand = #{generator}`

  if const_defined? :DEFAULT
    DEFAULT.reseed
  else
    const_set :DEFAULT, new(new_seed)
  end
end

.new_seed ⇒ Object 



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# File 'opal/opal/corelib/random.rb', line 15

def self.new_seed
  `Opal.$$rand.new_seed()`
end

.rand(limit = undefined) ⇒ Object 



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# File 'opal/opal/corelib/random.rb', line 19

def self.rand(limit = undefined)
  DEFAULT.rand(limit)
end

.srand(n = Random.new_seed) ⇒ Object 



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# File 'opal/opal/corelib/random.rb', line 23

def self.srand(n = Random.new_seed)
  n = Opal.coerce_to!(n, Integer, :to_int)

  previous_seed = DEFAULT.seed
  DEFAULT.reseed(n)
  previous_seed
end

.urandom(size) ⇒ Object 



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# File 'opal/opal/corelib/random.rb', line 31

def self.urandom(size)
  size = Opal.coerce_to!(size, Integer, :to_int)

  if size < 0
    raise ArgumentError, 'negative string size (or size too big)'
  end

  Array.new(size) { rand(255).chr }.join.encode('ASCII-8BIT')
end

Instance Method Details

#==(other) ⇒ Object 



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# File 'opal/opal/corelib/random.rb', line 41

def ==(other)
  return false unless Random === other

  seed == other.seed && state == other.state
end

#bytes(length) ⇒ Object 



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# File 'opal/opal/corelib/random.rb', line 47

def bytes(length)
  length = Opal.coerce_to!(length, Integer, :to_int)

  Array.new(length) { rand(255).chr }.join.encode('ASCII-8BIT')
end

#rand(limit = undefined) ⇒ Object 



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# File 'opal/opal/corelib/random.rb', line 53

def rand(limit = undefined)
  %x{
    function randomFloat() {
      self.state++;
      return Opal.$$rand.rand(self.$rng);
    }

    function randomInt() {
      return Math.floor(randomFloat() * limit);
    }

    function randomRange() {
      var min = limit.begin,
          max = limit.end;

      if (min === nil || max === nil) {
        return nil;
      }

      var length = max - min;

      if (length < 0) {
        return nil;
      }

      if (length === 0) {
        return min;
      }

      if (max % 1 === 0 && min % 1 === 0 && !limit.excl) {
        length++;
      }

      return self.$rand(length) + min;
    }

    if (limit == null) {
      return randomFloat();
    } else if (limit.$$is_range) {
      return randomRange();
    } else if (limit.$$is_number) {
      if (limit <= 0) {
        #{raise ArgumentError, "invalid argument - #{limit}"}
      }

      if (limit % 1 === 0) {
        // integer
        return randomInt();
      } else {
        return randomFloat() * limit;
      }
    } else {
      limit = #{Opal.coerce_to!(limit, Integer, :to_int)};

      if (limit <= 0) {
        #{raise ArgumentError, "invalid argument - #{limit}"}
      }

      return randomInt();
    }
  }
end

#reseed(seed) ⇒ Object 



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# File 'opal/opal/corelib/random.rb', line 10

def reseed(seed)
  @seed = seed
  `self.$rng = Opal.$$rand.reseed(seed)`
end