Class: Prime::PseudoPrimeGenerator

Inherits:
Object
  • Object
show all
Includes:
Enumerable
Defined in:
lib/prime.rb

Overview

An abstract class for enumerating pseudo-prime numbers.

Concrete subclasses should override succ, next, rewind.

Instance Method Summary collapse

Constructor Details

#initialize(ubound = nil) ⇒ PseudoPrimeGenerator

Returns a new instance of PseudoPrimeGenerator.



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# File 'lib/prime.rb', line 237

def initialize(ubound = nil)
  @ubound = ubound
end

Instance Method Details

#each ⇒ Object

Iterates the given block for each prime number.



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# File 'lib/prime.rb', line 269

def each
  return self.dup unless block_given?
  if @ubound
    last_value = nil
    loop do
      prime = succ
      break last_value if prime > @ubound
      last_value = yield prime
    end
  else
    loop do
      yield succ
    end
  end
end

#next ⇒ Object

alias of succ.

Raises:

  • (NotImplementedError) 


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# File 'lib/prime.rb', line 257

def next
  raise NotImplementedError, "need to define `next'"
end

#rewind ⇒ Object

Rewinds the internal position for enumeration.

See Enumerator#rewind.

Raises:

  • (NotImplementedError) 


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# File 'lib/prime.rb', line 264

def rewind
  raise NotImplementedError, "need to define `rewind'"
end

#size ⇒ Object 



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# File 'lib/prime.rb', line 304

def size
  Float::INFINITY
end

#succ ⇒ Object

returns the next pseudo-prime number, and move the internal position forward.

PseudoPrimeGenerator#succ raises NotImplementedError.

Raises:

  • (NotImplementedError) 


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# File 'lib/prime.rb', line 252

def succ
  raise NotImplementedError, "need to define `succ'"
end

#upper_bound ⇒ Object 



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# File 'lib/prime.rb', line 244

def upper_bound
  @ubound
end

#upper_bound=(ubound) ⇒ Object 



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# File 'lib/prime.rb', line 241

def upper_bound=(ubound)
  @ubound = ubound
end

#with_index(offset = 0, &block) ⇒ Object

see Enumerator#with_index.



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# File 'lib/prime.rb', line 286

def with_index(offset = 0, &block)
  return enum_for(:with_index, offset) { Float::INFINITY } unless block
  return each_with_index(&block) if offset == 0

  each do |prime|
    yield prime, offset
    offset += 1
  end
end

#with_object(obj) ⇒ Object

see Enumerator#with_object.



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# File 'lib/prime.rb', line 297

def with_object(obj)
  return enum_for(:with_object, obj) { Float::INFINITY } unless block_given?
  each do |prime|
    yield prime, obj
  end
end