Class: Containers::Queue

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

Overview

rdoc

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.

MIT License

Copyright (c) 2009 Kanwei Li

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.

Instance Method Summary collapse

Constructor Details

#initialize(ary = []) ⇒ Queue

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



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# File 'lib/containers/queue.rb', line 38

def initialize(ary=[])
  @container = Containers::Deque.new(ary)
end

Instance Method Details

#each(&block) ⇒ Object

Iterate over the Queue in FIFO order.



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# File 'lib/containers/queue.rb', line 85

def each(&block)
  @container.each_forward(&block)
end

#empty? ⇒ Boolean

Returns true if the queue is empty, false otherwise.

Returns:

  • (Boolean) 


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# File 'lib/containers/queue.rb', line 80

def empty?
  @container.empty?
end

#next ⇒ Object

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



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# File 'lib/containers/queue.rb', line 47

def next
  @container.front
end

#pop ⇒ Object

Removes the next item from the queue and returns it.

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



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# File 'lib/containers/queue.rb', line 67

def pop
  @container.pop_front
end

#push(obj) ⇒ Object Also known as: <<

Adds an item to the queue.

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



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# File 'lib/containers/queue.rb', line 57

def push(obj)
  @container.push_back(obj)
end

#size ⇒ Object

Return the number of items in the queue.

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



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# File 'lib/containers/queue.rb', line 75

def size
  @container.size
end