Move TextLines type to its own file

Author: Kapil Borle

Engine/EditableText.cs

@@ -184,248 +184,5 @@ private static int GetNumNewLineCharacters(string text, out string[] lines)
 
             return numCharDiff / (lines.Length - 1);
         }
-
-        private class TextLines : IList<String>
-        {
-            private LinkedList<String> lines;
-            private int lastAccessedIndex;
-            private LinkedListNode<String> lastAccessedNode;
-
-            private void ValidateIndex(int index)
-            {
-                if (index >= Count || index < 0)
-                {
-                    throw new ArgumentOutOfRangeException(nameof(index));
-                }
-            }
-
-            private void SetLastAccessed(int index, LinkedListNode<String> node)
-            {
-                lastAccessedIndex = index;
-                lastAccessedNode = node;
-            }
-
-            private void InvalidateLastAccessed()
-            {
-                lastAccessedIndex = -1;
-                lastAccessedNode = null;
-            }
-
-            private bool IsLastAccessedValid()
-            {
-                return lastAccessedIndex != -1;
-            }
-
-            private LinkedListNode<String> GetNodeAt(int index)
-            {
-                if (index == 0)
-                {
-                    return lines.First;
-                }
-
-                if (index == Count - 1)
-                {
-                    return lines.Last;
-                }
-
-                LinkedListNode<string> node;
-                int searchDirection;
-                int count;
-                GetClosestReference(index, out node, out count, out searchDirection);
-                while (node != null)
-                {
-                    if (count == index)
-                    {
-                        SetLastAccessed(index, node);
-                        return node;
-                    }
-
-                    count += searchDirection;
-                    if (searchDirection > 0)
-                    {
-                        node = node.Next;
-                    }
-                    else
-                    {
-                        node = node.Previous;
-                    }
-                }
-
-                throw new InvalidOperationException();
-            }
-
-            private void GetClosestReference(
-                int index,
-                out LinkedListNode<string> refNode,
-                out int refIndex,
-                out int searchDirection)
-            {
-                var delta = index - lastAccessedIndex;
-                var deltaAbs = Math.Abs(delta);
-
-                // lastAccessedIndex is closer to index than that to 0
-                if (IsLastAccessedValid() && deltaAbs < index)
-                {
-                    // lastAccessedIndex is closer to index than to (Count - 1)
-                    if (deltaAbs < (Count - 1 - index))
-                    {
-                        refNode = lastAccessedNode;
-                        refIndex = lastAccessedIndex;
-                        searchDirection = Math.Sign(delta);
-                    }
-                    else
-                    {
-                        refNode = lines.Last;
-                        refIndex = Count - 1;
-                        searchDirection = -1;
-                    }
-                }
-                else
-                {
-                    refNode = lines.First;
-                    refIndex = 0;
-                    searchDirection = 1;
-                }
-            }
-
-            public string this[int index]
-            {
-                get
-                {
-                    ValidateIndex(index);
-                    return GetNodeAt(index).Value;
-                }
-                set
-                {
-                    ValidateIndex(index);
-                    Insert(index, value);
-                    RemoveAt(index);
-                }
-            }
-
-            public int Count { get; private set; }
-
-            public bool IsReadOnly => false;
-
-            public TextLines()
-            {
-                lines = new LinkedList<String>();
-                Count = 0;
-                InvalidateLastAccessed();
-            }
-
-            public TextLines(IEnumerable<String> inputLines) : this()
-            {
-                if (inputLines == null)
-                {
-                    throw new ArgumentNullException(nameof(inputLines));
-                }
-
-                if (inputLines.Any(line => line == null))
-                {
-                    // todo localize
-                    throw new ArgumentException("Line element cannot be null.");
-                }
-
-                lines = new LinkedList<String>(inputLines);
-                Count = lines.Count;
-            }
-
-            public void Add(string item)
-            {
-                if (item == null)
-                {
-                    throw new ArgumentNullException(nameof(item));
-                }
-
-                Insert(Count - 1, item);
-            }
-
-            public void Clear()
-            {
-                lines.Clear();
-            }
-
-            public bool Contains(string item)
-            {
-                return lines.Contains(item);
-            }
-
-            public void CopyTo(string[] array, int arrayIndex)
-            {
-                lines.CopyTo(array, arrayIndex);
-            }
-
-            public IEnumerator<string> GetEnumerator()
-            {
-                return lines.GetEnumerator();
-            }
-
-            public int IndexOf(string item)
-            {
-                var llNode = lines.First;
-                int count = 0;
-                while (llNode != null)
-                {
-                    if (llNode.Value.Equals(item))
-                    {
-                        return count;
-                    }
-
-                    llNode = llNode.Next;
-                    count++;
-                }
-
-                return -1;
-            }
-
-            public void Insert(int index, string item)
-            {
-                ValidateIndex(index);
-                SetLastAccessed(index, lines.AddBefore(GetNodeAt(index), item));
-                Count++;
-            }
-
-            public bool Remove(string item)
-            {
-                if (lines.Remove(item))
-                {
-                    Count--;
-                    return true;
-                }
-
-                return false;
-            }
-
-            public void RemoveAt(int index)
-            {
-                var node = GetNodeAt(index);
-                if (node.Next != null)
-                {
-                    SetLastAccessed(index, node.Next);
-                }
-                else if (node.Previous != null)
-                {
-                    SetLastAccessed(index - 1, node.Previous);
-                }
-                else
-                {
-                    InvalidateLastAccessed();
-                }
-
-                lines.Remove(node);
-                Count--;
-            }
-
-            IEnumerator IEnumerable.GetEnumerator()
-            {
-                return lines.GetEnumerator();
-            }
-
-            public override string ToString()
-            {
-                return String.Join(Environment.NewLine, lines);
-            }
-        }
     }
 }