1 files changed, 152 insertions, 0 deletions
diff --git a/Assets/uGUI-2017.1/UnityEngine.UI/UI/Core/SpecializedCollections/IndexedSet.cs b/Assets/uGUI-2017.1/UnityEngine.UI/UI/Core/SpecializedCollections/IndexedSet.cs
new file mode 100644
index 0000000..0f37983
--- /dev/null
+++ b/Assets/uGUI-2017.1/UnityEngine.UI/UI/Core/SpecializedCollections/IndexedSet.cs
@@ -0,0 +1,152 @@
+using System;
+using System.Collections;
+using System.Collections.Generic;
+
+namespace UnityEngine.UI.Collections
+{
+    internal class IndexedSet<T> : IList<T>
+    {
+        //This is a container that gives:
+        //  - Unique items
+        //  - Fast random removal
+        //  - Fast unique inclusion to the end
+        //  - Sequential access
+        //Downsides:
+        //  - Uses more memory
+        //  - Ordering is not persistent
+        //  - Not Serialization Friendly.
+
+        //We use a Dictionary to speed up list lookup, this makes it cheaper to guarantee no duplicates (set)
+        //When removing we move the last item to the removed item position, this way we only need to update the index cache of a single item. (fast removal)
+        //Order of the elements is not guaranteed. A removal will change the order of the items.
+
+        readonly List<T> m_List = new List<T>();
+        Dictionary<T, int> m_Dictionary = new Dictionary<T, int>();
+
+        public void Add(T item)
+        {
+            m_List.Add(item);
+            m_Dictionary.Add(item, m_List.Count - 1);
+        }
+
+        public bool AddUnique(T item)
+        {
+            if (m_Dictionary.ContainsKey(item))
+                return false;
+
+            m_List.Add(item);
+            m_Dictionary.Add(item, m_List.Count - 1);
+
+            return true;
+        }
+
+        public bool Remove(T item)
+        {
+            int index = -1;
+            if (!m_Dictionary.TryGetValue(item, out index))
+                return false;
+
+            RemoveAt(index);
+            return true;
+        }
+
+        public IEnumerator<T> GetEnumerator()
+        {
+            throw new System.NotImplementedException();
+        }
+
+        IEnumerator IEnumerable.GetEnumerator()
+        {
+            return GetEnumerator();
+        }
+
+        public void Clear()
+        {
+            m_List.Clear();
+            m_Dictionary.Clear();
+        }
+
+        public bool Contains(T item)
+        {
+            return m_Dictionary.ContainsKey(item);
+        }
+
+        public void CopyTo(T[] array, int arrayIndex)
+        {
+            m_List.CopyTo(array, arrayIndex);
+        }
+
+        public int Count { get { return m_List.Count; } }
+        public bool IsReadOnly { get { return false; } }
+        public int IndexOf(T item)
+        {
+            int index = -1;
+            m_Dictionary.TryGetValue(item, out index);
+            return index;
+        }
+
+        public void Insert(int index, T item)
+        {
+            //We could support this, but the semantics would be weird. Order is not guaranteed..
+            throw new NotSupportedException("Random Insertion is semantically invalid, since this structure does not guarantee ordering.");
+        }
+
+        public void RemoveAt(int index)
+        {
+            T item = m_List[index];
+            m_Dictionary.Remove(item);
+            if (index == m_List.Count - 1)
+                m_List.RemoveAt(index);
+            else
+            {
+                int replaceItemIndex = m_List.Count - 1;
+                T replaceItem = m_List[replaceItemIndex];
+                m_List[index] = replaceItem;
+                m_Dictionary[replaceItem] = index;
+                m_List.RemoveAt(replaceItemIndex);
+            }
+        }
+
+        public T this[int index]
+        {
+            get { return m_List[index]; }
+            set
+            {
+                T item = m_List[index];
+                m_Dictionary.Remove(item);
+                m_List[index] = value;
+                m_Dictionary.Add(item, index); // 这里有问题，应该是value
+            }
+        }
+
+        public void RemoveAll(Predicate<T> match)
+        {
+            //I guess this could be optmized by instead of removing the items from the list immediatly,
+            //We move them to the end, and then remove all in one go.
+            //But I don't think this is going to be the bottleneck, so leaving as is for now.
+            int i = 0;
+            while (i < m_List.Count)
+            {
+                T item = m_List[i];
+                if (match(item))
+                    Remove(item);
+                else
+                    i++;
+            }
+        }
+
+        //Sorts the internal list, this makes the exposed index accessor sorted as well.
+        //But note that any insertion or deletion, can unorder the collection again.
+        public void Sort(Comparison<T> sortLayoutFunction)
+        {
+            //There might be better ways to sort and keep the dictionary index up to date.
+            m_List.Sort(sortLayoutFunction);
+            //Rebuild the dictionary index.
+            for (int i = 0; i < m_List.Count; ++i)
+            {
+                T item = m_List[i];
+                m_Dictionary[item] = i;
+            }
+        }
+    }
+}