Jeremy Koritzinsky
8 years ago
committed by
GitHub
GitHub
21 changed files with 349 additions and 119 deletions
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using System; |
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using System.Collections.Generic; |
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using System.Text; |
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namespace Avalonia.Utilities |
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{ |
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/// <summary>
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/// FIFO Queue optimized for holding zero or one items.
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/// </summary>
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/// <typeparam name="T">The type of items held in the queue.</typeparam>
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public class SingleOrQueue<T> |
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{ |
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private T _head; |
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private Queue<T> _tail; |
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private Queue<T> Tail => _tail ?? (_tail = new Queue<T>()); |
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private bool HasTail => _tail != null; |
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public bool Empty { get; private set; } = true; |
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public void Enqueue(T value) |
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{ |
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if (Empty) |
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{ |
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_head = value; |
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} |
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else |
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{ |
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Tail.Enqueue(value); |
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} |
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Empty = false; |
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} |
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public T Dequeue() |
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{ |
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if (Empty) |
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{ |
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throw new InvalidOperationException("Cannot dequeue from an empty queue!"); |
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} |
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var result = _head; |
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if (HasTail && Tail.Count != 0) |
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{ |
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_head = Tail.Dequeue(); |
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} |
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else |
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{ |
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_head = default; |
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Empty = true; |
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} |
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return result; |
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} |
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} |
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} |
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@ -0,0 +1,50 @@ |
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using Avalonia.Utilities; |
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using System; |
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using System.Collections.Generic; |
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using System.Text; |
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using Xunit; |
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namespace Avalonia.Base.UnitTests.Utilities |
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{ |
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public class SingleOrQueueTests |
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{ |
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[Fact] |
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public void New_SingleOrQueue_Is_Empty() |
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{ |
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Assert.True(new SingleOrQueue<object>().Empty); |
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} |
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[Fact] |
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public void Dequeue_Throws_When_Empty() |
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{ |
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var queue = new SingleOrQueue<object>(); |
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Assert.Throws<InvalidOperationException>(() => queue.Dequeue()); |
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} |
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[Fact] |
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public void Enqueue_Adds_Element() |
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{ |
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var queue = new SingleOrQueue<int>(); |
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queue.Enqueue(1); |
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Assert.False(queue.Empty); |
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Assert.Equal(1, queue.Dequeue()); |
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} |
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[Fact] |
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public void Multiple_Elements_Dequeued_In_Correct_Order() |
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{ |
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var queue = new SingleOrQueue<int>(); |
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queue.Enqueue(1); |
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queue.Enqueue(2); |
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queue.Enqueue(3); |
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Assert.Equal(1, queue.Dequeue()); |
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Assert.Equal(2, queue.Dequeue()); |
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Assert.Equal(3, queue.Dequeue()); |
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} |
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} |
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} |
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After Width: | Height: | Size: 250 B |
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After Width: | Height: | Size: 250 B |
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