IsoList for fast Pop

Assets/IsoTools/Scripts/Internal/IsoList.cs

@@ -0,0 +1,110 @@
+using System;
+
+namespace IsoTools.Internal {
+	public class IsoList<T> {
+		T[] _data;
+		int _size;
+
+		static readonly T[] _emptyData       = new T[0];
+		const int           _defaultCapacity = 4;
+
+		public IsoList() {
+			_data = _emptyData;
+			_size = 0;
+		}
+
+		public IsoList(int capacity) {
+			if ( capacity < 0 ) {
+				throw new ArgumentOutOfRangeException(
+					"capacity", "capacity must be >= 0");
+			} else if ( capacity == 0 ) {
+				_data = _emptyData;
+				_size = 0;
+			} else {
+				_data = new T[capacity];
+				_size = 0;
+			}
+		}
+
+		public void Push(T value) {
+			if ( _size == _data.Length ) {
+				var new_capacity = _size == 0
+					? _defaultCapacity : _size * 2;
+				var new_data = new T[new_capacity];
+				Array.Copy(_data, new_data, _size);
+				_data = new_data;
+			}
+			_data[_size++] = value;
+		}
+
+		public T Pop() {
+			if ( _size == 0 ) {
+				throw new InvalidOperationException("empty list");
+			}
+			var last = _data[--_size];
+			_data[_size] = default(T);
+			return last;
+		}
+
+		public T Peek() {
+			if ( _size == 0 ) {
+				throw new InvalidOperationException("empty list");
+			}
+			return _data[_size - 1];
+		}
+
+		public void Clear() {
+			Array.Clear(_data, 0, _size);
+			_size = 0;
+		}
+
+		public T UnorderedRemoveAt(int index) {
+			if ( (uint)index >= (uint)_size ) {
+				throw new IndexOutOfRangeException();
+			}
+			var last = _data[_size - 1];
+			_data[index] = last;
+			_data[--_size] = default(T);
+			return last;
+		}
+
+		public T this[int index] {
+			get {
+				if ( (uint)index >= (uint)_size ) {
+					throw new IndexOutOfRangeException();
+				}
+				return _data[index];
+			}
+			set {
+				if ( (uint)index >= (uint)_size ) {
+					throw new IndexOutOfRangeException();
+				}
+				_data[index] = value;
+			}
+		}
+
+		public int Count {
+			get { return _size; }
+		}
+
+		public int Capacity {
+			get { return _data.Length; }
+			set {
+				if ( value < _size ) {
+					throw new ArgumentOutOfRangeException("capacity");
+				}
+				if ( value != _data.Length ) {
+					if ( value > 0 ) {
+						var new_data = new T[value];
+						if ( _size > 0 ) {
+							Array.Copy(_data, new_data, _size);
+						}
+						_data = new_data;
+					} else {
+						_data = _emptyData;
+					}
+				}
+			}
+		}
+	}
+}