List class which stores objects (not pointers) or plain old data.

src/apps/haiku-depot/List.h

@@ -0,0 +1,196 @@
+/*
+ * Copyright 2009-2012, Stephan Aßmus <superstippi@gmx.de>
+ * All rights reserved. Distributed under the terms of the MIT License.
+ */
+#ifndef LIST_H
+#define LIST_H
+
+
+#include <new>
+#include <stdlib.h>
+
+#include <SupportDefs.h>
+
+
+template <typename ItemType, bool PlainOldData, uint32 BlockSize = 8>
+class List {
+	typedef List<ItemType, PlainOldData, BlockSize> SelfType;
+public:
+	List()
+		:
+		fItems(NULL),
+		fCount(0),
+		fAllocatedCount(0)
+	{
+	}
+
+	List(const SelfType& other)
+		:
+		fItems(NULL),
+		fCount(0),
+		fAllocatedCount(0)
+	{
+		*this = other;
+	}
+
+	virtual ~List()
+	{
+		if (!PlainOldData) {
+			// Make sure to call destructors of old objects.
+			_Resize(0);
+		}
+		free(fItems);
+	}
+
+	SelfType& operator=(const SelfType& other)
+	{
+		if (this == &other)
+			return *this;
+
+		if (PlainOldData) {
+			if (_Resize(other.fCount))
+				memcpy(fItems, other.fItems, fCount * sizeof(ItemType));
+		} else {
+			// Make sure to call destructors of old objects.
+			// NOTE: Another option would be to use
+			// ItemType::operator=(const ItemType& other), but then
+			// we would need to be carefull which objects are already
+			// initialized. Also the ItemType requires to implement the
+			// operator, while doing it this way requires only a copy
+			// constructor.
+			_Resize(0);
+			for (uint32 i = 0; i < other.fCount; i++) {
+				if (!Add(other.ItemAtFast(i)))
+					break;
+			}
+		}
+		return *this;
+	}
+
+	bool operator==(const SelfType& other) const
+	{
+		if (this == &other)
+			return true;
+
+		if (fCount != other.fCount)
+			return false;
+		if (fCount == 0)
+			return true;
+
+		if (PlainOldData) {
+			return memcmp(fItems, other.fItems,
+				fCount * sizeof(ItemType)) == 0;
+		} else {
+			for (uint32 i = 0; i < other.fCount; i++) {
+				if (ItemAtFast(i) != other.ItemAtFast(i))
+					return false;
+			}
+		}
+		return true;
+	}
+
+	bool operator!=(const SelfType& other) const
+	{
+		return !(*this == other);
+	}
+
+	inline void Clear()
+	{
+		_Resize(0);
+	}
+
+	inline int32 CountItems() const
+	{
+		return fCount;
+	}
+
+	inline bool Add(const ItemType& copyFrom)
+	{
+		if (_Resize(fCount + 1)) {
+			ItemType* item = fItems + fCount - 1;
+			// Initialize the new object from the original.
+			if (!PlainOldData)
+				new (item) ItemType(copyFrom);
+			else
+				*item = copyFrom;
+			return true;
+		}
+		return false;
+	}
+
+	inline void Remove()
+	{
+		if (fCount > 0)
+			_Resize(fCount - 1);
+	}
+	
+	inline void Remove(int32 index)
+	{
+		if (index < 0 || index >= (int32)fCount)
+			return;
+
+		if (!PlainOldData) {
+			ItemType* object = fItems + index;
+			object->~ItemType();
+		}
+
+		int32 nextIndex = index + 1;
+		if ((int32)fCount > nextIndex)
+			memcpy(fItems + index, fItems + nextIndex,
+				(fCount - nextIndex) * sizeof(ItemType));
+		
+		fCount--;
+	}
+
+	inline const ItemType& ItemAt(int32 index) const
+	{
+		if (index >= (int32)fCount)
+			return fNullItem;
+		return ItemAtFast(index);
+	}
+
+	inline const ItemType& ItemAtFast(int32 index) const
+	{
+		return *(fItems + index);
+	}
+
+	inline const ItemType& LastItem() const
+	{
+		return ItemAt((int32)fCount - 1);
+	}
+
+private:
+	inline bool _Resize(uint32 count)
+	{
+		if (count > fAllocatedCount) {
+			uint32 allocationCount = (count + BlockSize - 1)
+				/ BlockSize * BlockSize;
+			ItemType* items = reinterpret_cast<ItemType*>(
+				realloc(fItems, allocationCount * sizeof(ItemType)));
+			if (items == NULL)
+				return false;
+			fItems = items;
+
+			fAllocatedCount = allocationCount;
+		} else if (count < fCount) {
+			if (!PlainOldData) {
+				// Uninit old objects so that we can re-use them when
+				// appending objects without the need to re-allocate.
+				for (uint32 i = count; i < fCount; i++) {
+					ItemType* object = fItems + i;
+					object->~ItemType();
+				}
+			}
+		}
+		fCount = count;
+		return true;
+	}
+
+	ItemType*		fItems;
+	ItemType		fNullItem;
+	uint32			fCount;
+	uint32			fAllocatedCount;
+};
+
+
+#endif // LIST_H