Containers::Queue

A Queue is a container that keeps elements in a first-in first-out (FIFO) order. Because of its properties, it is often used as a buffer.

This implementation uses a doubly-linked list, guaranteeing O(1) complexity for all operations.

Methods

<< -> push

new (ary=[])

Create a new queue. Takes an optional array argument to initialize the queue.

q = Containers::Queue.new([1, 2, 3])
q.pop #=> 1
q.pop #=> 2

# File lib/containers/queue.rb, line 17
def initialize(ary=[])
  @container = Containers::Deque.new(ary)
end

each (&block)

Iterate over the Queue in FIFO order.

# File lib/containers/queue.rb, line 64
def each(&block)
  @container.each_forward(&block)
end

empty? ()

Returns true if the queue is empty, false otherwise.

# File lib/containers/queue.rb, line 59
def empty?
  @container.empty?
end

next ()

Returns the next item from the queue but does not remove it.

q = Containers::Queue.new([1, 2, 3])
q.next #=> 1
q.size #=> 3

# File lib/containers/queue.rb, line 26
def next
  @container.front
end

pop ()

Removes the next item from the queue and returns it.

q = Containers::Queue.new([1, 2, 3])
q.pop #=> 1
q.size #=> 2

# File lib/containers/queue.rb, line 46
def pop
  @container.pop_front
end

push (obj)

Adds an item to the queue.

q = Containers::Queue.new([1])
q.push(2)
q.pop #=> 1
q.pop #=> 2

# File lib/containers/queue.rb, line 36
def push(obj)
  @container.push_back(obj)
end

size ()

Return the number of items in the queue.

q = Containers::Queue.new([1, 2, 3])
q.size #=> 3

# File lib/containers/queue.rb, line 54
def size
  @container.size
end