Fix bugs in deque

Author: npcook

Diff for: TerminalControl/Deque.cs

@@ -128,12 +128,21 @@ IEnumerator<T> IEnumerable<T>.GetEnumerator()
 
 		public void CopyTo(Array array, int index)
 		{
-			Array.Copy(backing, start, array, index, size);
+			bool contiguous = end > start;
+			if (contiguous)
+			{
+				Array.Copy(backing, start, array, index, size);
+			}
+			else
+			{
+				Array.Copy(backing, start, array, index, backing.Length - start);
+				Array.Copy(backing, 0, array, index + backing.Length - start, end);
+			}
 		}
 
 		public void CopyTo(T[] array, int index)
 		{
-			Array.Copy(backing, start, array, index, size);
+			CopyTo((Array) array, index);
 		}
 
 		public T this[int index]
@@ -164,8 +173,24 @@ public bool Contains(T value)
 
 		public void Insert(int index, T value)
 		{
-			Array.Copy(backing, index, backing, index + 1, size - index);
-			backing[index] = value;
+			if (index < 0 || index >= size)
+				throw new ArgumentOutOfRangeException(nameof(index), index, "Index has to be within the bounds of the collection");
+			if (size == backing.Length)
+				resize(size * GrowthMultiplier);
+
+			int actualIndex = (start + index) % backing.Length;
+			bool contiguous = end > actualIndex;
+			if (contiguous)
+			{
+				Array.Copy(backing, actualIndex, backing, actualIndex + 1, size - actualIndex);
+			}
+			else
+			{
+				Array.Copy(backing, 0, backing, 1, end);
+				backing[0] = backing[backing.Length - 1];
+				Array.Copy(backing, actualIndex, backing, actualIndex + 1, backing.Length - actualIndex - 1);
+			}
+			backing[actualIndex] = value;
 			end = (end + 1) % backing.Length;
 			size++;
 		}
@@ -194,6 +219,12 @@ public void RemoveAt(int index)
 			if (index < 0 || index >= size)
 				throw new ArgumentOutOfRangeException(nameof(index), index, "Index has to be within the bounds of the collection");
 
+			if (index == 0)
+			{
+				PopFront();
+				return;
+			}
+
 			int actualIndex = (start + index) % backing.Length;
 			int copyCount = Math.Min(size - index - 1, backing.Length - actualIndex - 1);
 			Array.Copy(backing, actualIndex + 1, backing, actualIndex, copyCount);

Diff for: TerminalControlTests/DequeTests.cs

@@ -18,29 +18,41 @@ public void TestInsert()
 			test.Add(4);
 			test.Add(5);
 			test.Add(6);
+			test.Add(7);
+			test.Add(8);
+			test.Add(9);
+			test.RemoveAt(0);
+			test.RemoveAt(0);
 			test.Insert(3, 7);
 			test.Insert(3, 8);
 
-			CollectionAssert.AreEqual(test.ToArray(), new int[] { 0, 1, 2, 8, 7, 3, 4, 5, 6 });
-			Assert.AreEqual(test.Count, 9);
+			CollectionAssert.AreEqual(test.ToArray(), new int[] { 2, 3, 4, 8, 7, 5, 6, 7, 8, 9 });
+			Assert.AreEqual(test.Count, 10);
 		}
 
 		[TestMethod]
 		public void TestRemoveAt()
 		{
-			Deque<int> test = new Deque<int>(10);
+			Deque<int> test = new Deque<int>(6);
 			test.Add(0);
 			test.Add(1);
 			test.Add(2);
 			test.Add(3);
 			test.Add(4);
 			test.Add(5);
+
+			test.PopFront();
+			test.PopFront();
+
 			test.Add(6);
+			test.Add(7);
 
 			test.RemoveAt(2);
 
-			CollectionAssert.AreEqual(test.ToArray(), new int[] { 0, 1, 3, 4, 5, 6 });
-			Assert.AreEqual(test.Count, 6);
+			int[] arr = test.ToArray();
+
+			CollectionAssert.AreEqual(arr, new int[] { 2, 3, 5, 6, 7 });
+			Assert.AreEqual(test.Count, 5);
 		}
 	}
 }