Class: Depq::Locator

Inherits:
Struct
  • Object
show all
Defined in:
lib/depq.rb,
lib/depq.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(value, priority = value, subpriority = nil) ⇒ Locator

Create a Depq::Locator object.

loc = Depq::Locator.new("a", 1, 2)
p loc.value             #=> "a"
p loc.priority          #=> 1
p loc.subpriority       #=> 2



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

def initialize(value, priority=value, subpriority=nil)
  super value, subpriority, priority
end

Instance Attribute Details

#value ⇒ Object

Returns the value of attribute value

Returns:

  • (Object) —

    the current value of value



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# File 'lib/depq.rb', line 198

def value
  @value
end

Instance Method Details

#depq ⇒ Object Also known as: queue

returns the queue.

nil is returned if the locator is not in a queue.



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# File 'lib/depq.rb', line 280

def depq
  in_queue? ? depq_or_subpriority() : nil
end

#in_queue? ⇒ Boolean

returns true if the locator is in a queue.

Returns:

  • (Boolean) 


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# File 'lib/depq.rb', line 273

def in_queue?
  depq_or_subpriority().kind_of? Depq
end

#initialize_copy(obj) ⇒ Object

:nodoc:

Raises:

  • (TypeError) 


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# File 'lib/depq.rb', line 268

def initialize_copy(obj) # :nodoc:
  raise TypeError, "can not duplicated"
end

#inspect ⇒ Object Also known as: to_s 



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# File 'lib/depq.rb', line 253

def inspect
  prio = self.priority
  if self.value == prio
    s = self.value.inspect
  else
    s = "#{self.value.inspect}:#{prio.inspect}"
  end
  if in_queue?
    "\#<#{self.class}: #{s}>"
  else
    "\#<#{self.class}: #{s} (no queue)>"
  end
end

#priority ⇒ Object

returns the priority.



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# File 'lib/depq.rb', line 299

def priority
  if in_queue?
    q = depq_or_subpriority()
    priority, _subpriority = q.send(:internal_get_priority, self)
    priority
  else
    index_or_priority()
  end
end

#subpriority ⇒ Object

returns the subpriority.



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# File 'lib/depq.rb', line 310

def subpriority
  if in_queue?
    q = depq_or_subpriority()
    _priority, subpriority = q.send(:internal_get_priority, self)
    subpriority
  else
    depq_or_subpriority()
  end
end

#update(value, priority = value, subpriority = nil) ⇒ Object

update the value, priority and subpriority.

subpriority cannot be nil if the locator is in a queue. So subpriority is not changed if subpriority is not specified or nil for a locator in a queue. subpriority is set to nil if subpriority is not specified or nil for a locator not in a queue.

q = Depq.new
loc1 = q.insert 1, 2, 3
p [loc1.value, loc1.priority, loc1.subpriority] #=> [1, 2, 3]
loc1.update(11, 12)
p [loc1.value, loc1.priority, loc1.subpriority] #=> [11, 12, 3]

loc2 = Depq::Locator.new(4, 5, 6)
p [loc2.value, loc2.priority, loc2.subpriority] #=> [4, 5, 6]
loc2.update(14, 15)
p [loc2.value, loc2.priority, loc2.subpriority] #=> [14, 15, nil]

This feature is called as decrease-key/increase-key in Computer Science terminology.



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# File 'lib/depq.rb', line 339

def update(value, priority=value, subpriority=nil)
  subpriority = Integer(subpriority) if subpriority != nil
  if in_queue?
    q = depq_or_subpriority()
    if subpriority == nil
      subpriority = self.subpriority
    else
      subpriority = Integer(subpriority)
    end
    q.send(:internal_set_priority, self, priority, subpriority)
  else
    self.index_or_priority = priority
    self.depq_or_subpriority = subpriority
  end
  self.value = value
  nil
end

#update_priority(priority, subpriority = nil) ⇒ Object

update the priority and subpriority.

This method doesn’t change the value.

q = Depq.new
loc = q.insert 1, 2, 3
p [loc.value, loc.priority, loc.subpriority] #=> [1, 2, 3]
loc.update_priority 10
p [loc.value, loc.priority, loc.subpriority] #=> [1, 10, 3]
loc.update_priority 20, 30
p [loc.value, loc.priority, loc.subpriority] #=> [1, 20, 30]



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# File 'lib/depq.rb', line 383

def update_priority(priority, subpriority=nil)
  update(self.value, priority, subpriority)
end

#update_value(value) ⇒ Object

update the value.

This method doesn’t change the priority and subpriority.

q = Depq.new
loc = q.insert 1, 2, 3
p [loc.value, loc.priority, loc.subpriority]    #=> [1, 2, 3]
loc.update_value 10
p [loc.value, loc.priority, loc.subpriority]    #=> [10, 2, 3]



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# File 'lib/depq.rb', line 367

def update_value(value)
  update(value, self.priority, self.subpriority)
end