fahhh

App/util/IndexArray.h

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+/* Copyright 2003-2005 ROBLOX Corporation, All Rights Reserved */
+
+#pragma once
+
+#include "boost/utility.hpp"
+#include "util/utilities.h"
+#include "Util/G3DCore.h"
+#include "rbx/Debug.h"
+#include "G3D/Array.h"
+
+namespace RBX {
+
+/* USAGE
+	class C 
+	{
+	private:
+		int	index;
+
+	public:
+		C() : index(-1) {}
+		~C() {RBXASSERT(index == -1);}
+
+		int&	getIndex() {return index;}
+	};
+
+
+	main()
+	{
+		IndexArray<C, &C::getIndex> array;
+
+		C* c = new C();
+		C  c2;
+
+		array.fastAppend(c);
+		array.fastAppend(&c2);
+
+		array.fastRemove(c)
+		array.fastRemove(&c2);
+	}
+*/
+
+	template <class Item, int& (Item::*getIndex)()>
+	class IndexArray 
+		: public boost::noncopyable // You can't copy elements from one array to another
+		                    // since the index values can't be shared.
+	{
+	private:
+		G3D::Array<Item*> array;
+
+		int& indexOf(Item* item) const {
+			return (item->*getIndex)();
+		}
+
+	public:
+	    typedef Item** Iterator;
+	    typedef const Item** ConstIterator;
+
+		inline void fastAppend(Item* item)
+		{
+			RBXASSERT(item);
+			RBXASSERT(indexOf(item) == -1);
+			RBXASSERT_IF_VALIDATING(array.find(item) == array.end());
+
+			indexOf(item) = array.size();
+			array.append(item);
+		}
+
+		inline void fastRemove(Item* item)
+		{
+			RBXASSERT_IF_VALIDATING(array.find(item) != array.end());
+
+			int removeIndex = indexOf(item);
+
+			RBXASSERT(removeIndex >= 0);
+			RBXASSERT(array[removeIndex] == item);
+
+			// Move last item to removal index
+			Item* oldLast = array.last();		// if array size == 1, this is redundant
+			array[removeIndex] = oldLast;
+			indexOf(oldLast) = removeIndex;
+			array.pop(false);
+
+			// Update indices
+			indexOf(item) = -1;
+		}
+
+		inline void remove(Item* item)
+		{
+			RBXASSERT_IF_VALIDATING(array.find(item) != array.end());
+
+			int removeIndex = indexOf(item);
+
+			RBXASSERT(removeIndex >= 0);
+			RBXASSERT(array[removeIndex] == item);
+
+			// Move all the items back in the array. 
+			for (int i = removeIndex; i < array.size() - 1; i++)
+			{
+				Item* nextItem = array[i + 1];
+				array[i] = nextItem;
+				indexOf(nextItem) = i;
+			}
+
+			array.pop(false);
+
+			// Update indices
+			indexOf(item) = -1;
+		}
+
+		inline bool fastContains(Item* item) const
+		{
+			bool answer = (indexOf(item) >= 0);
+			RBXASSERT_IF_VALIDATING(answer == underlyingArray().contains(item));
+			return answer;
+		}
+
+		G3D::Array<Item*>& underlyingArray() {
+			return array;
+		}
+
+		const G3D::Array<Item*>& underlyingArray() const {
+			return array;
+		}
+
+		inline Item* operator[](int n) {
+			RBXASSERT(indexOf(array[n]) == n);
+			return array[n];
+		}
+
+		inline Item* operator[](unsigned int n) {
+			RBXASSERT(indexOf(array[n]) == n);
+			return array[n];
+		}
+
+		inline Item* const operator[](int n) const {		// the pointer is const?
+			RBXASSERT(indexOf(array[n]) == n);
+			return array[n];
+		}
+
+		inline Item* const operator[](unsigned int n) const {	// the pointer is const?...
+			RBXASSERT(indexOf(array[n]) == n);
+			return array[n];
+		}
+
+		inline int size() const {
+		   return array.size();
+		}
+	   
+	};
+
+}// namespace
+
+
+