Imported existing code

indra/llcommon/lllinkedqueue.h

@@ -0,0 +1,315 @@
+/** 
+ * @file lllinkedqueue.h
+ * @brief Declaration of linked queue classes.
+ *
+ * $LicenseInfo:firstyear=2003&license=viewergpl$
+ * 
+ * Copyright (c) 2003-2009, Linden Research, Inc.
+ * 
+ * Second Life Viewer Source Code
+ * The source code in this file ("Source Code") is provided by Linden Lab
+ * to you under the terms of the GNU General Public License, version 2.0
+ * ("GPL"), unless you have obtained a separate licensing agreement
+ * ("Other License"), formally executed by you and Linden Lab.  Terms of
+ * the GPL can be found in doc/GPL-license.txt in this distribution, or
+ * online at http://secondlifegrid.net/programs/open_source/licensing/gplv2
+ * 
+ * There are special exceptions to the terms and conditions of the GPL as
+ * it is applied to this Source Code. View the full text of the exception
+ * in the file doc/FLOSS-exception.txt in this software distribution, or
+ * online at
+ * http://secondlifegrid.net/programs/open_source/licensing/flossexception
+ * 
+ * By copying, modifying or distributing this software, you acknowledge
+ * that you have read and understood your obligations described above,
+ * and agree to abide by those obligations.
+ * 
+ * ALL LINDEN LAB SOURCE CODE IS PROVIDED "AS IS." LINDEN LAB MAKES NO
+ * WARRANTIES, EXPRESS, IMPLIED OR OTHERWISE, REGARDING ITS ACCURACY,
+ * COMPLETENESS OR PERFORMANCE.
+ * $/LicenseInfo$
+ */
+
+#ifndef LL_LLLINKEDQUEUE_H
+#define LL_LLLINKEDQUEUE_H
+
+#include "llerror.h"
+
+// node that actually contains the data
+template <class DATA_TYPE> class LLLinkedQueueNode
+{
+public:
+	DATA_TYPE			mData;
+	LLLinkedQueueNode	*mNextp;
+	LLLinkedQueueNode	*mPrevp;
+
+
+public:
+	LLLinkedQueueNode();
+	LLLinkedQueueNode(const DATA_TYPE data);
+
+	// destructor does not, by default, destroy associated data
+	// however, the mDatap must be NULL to ensure that we aren't causing memory leaks
+	~LLLinkedQueueNode();
+};
+
+
+
+template <class DATA_TYPE> class LLLinkedQueue
+{
+
+public:
+	LLLinkedQueue();
+
+	// destructor destroys list and nodes, but not data in nodes
+	~LLLinkedQueue();
+
+	// Puts at end of FIFO
+	void push(const DATA_TYPE data);
+
+	// Takes off front of FIFO
+	BOOL pop(DATA_TYPE &data);
+	BOOL peek(DATA_TYPE &data);
+
+	void reset();
+
+	S32 getLength() const;
+
+	BOOL isEmpty() const;
+
+	BOOL remove(const DATA_TYPE data);
+
+	BOOL checkData(const DATA_TYPE data) const;
+
+private:
+	// add node to end of list
+	// set mCurrentp to mQueuep
+	void addNodeAtEnd(LLLinkedQueueNode<DATA_TYPE> *nodep);
+
+private:
+	LLLinkedQueueNode<DATA_TYPE> mHead;		// head node
+	LLLinkedQueueNode<DATA_TYPE> mTail;		// tail node
+	S32 mLength;
+};
+
+
+//
+// Nodes
+//
+
+template <class DATA_TYPE>
+LLLinkedQueueNode<DATA_TYPE>::LLLinkedQueueNode() : 
+	mData(), mNextp(NULL), mPrevp(NULL)
+{ }
+
+template <class DATA_TYPE>
+LLLinkedQueueNode<DATA_TYPE>::LLLinkedQueueNode(const DATA_TYPE data) : 
+	mData(data), mNextp(NULL), mPrevp(NULL)
+{ }
+
+template <class DATA_TYPE>
+LLLinkedQueueNode<DATA_TYPE>::~LLLinkedQueueNode()
+{ }
+
+
+//
+// Queue itself
+//
+
+template <class DATA_TYPE>
+LLLinkedQueue<DATA_TYPE>::LLLinkedQueue()
+:	mHead(), 
+	mTail(), 
+	mLength(0)
+{ }
+
+
+// destructor destroys list and nodes, but not data in nodes
+template <class DATA_TYPE>
+LLLinkedQueue<DATA_TYPE>::~LLLinkedQueue()
+{
+	reset();
+}
+
+
+// put data into a node and stick it at the end of the list
+template <class DATA_TYPE>
+void LLLinkedQueue<DATA_TYPE>::push(const DATA_TYPE data)
+{
+	// make the new node
+	LLLinkedQueueNode<DATA_TYPE> *nodep = new LLLinkedQueueNode<DATA_TYPE>(data);
+
+	addNodeAtEnd(nodep);
+}
+
+
+// search the list starting at mHead.mNextp and remove the link with mDatap == data
+// set mCurrentp to mQueuep, or NULL if mQueuep points to node with mDatap == data
+// return TRUE if found, FALSE if not found
+template <class DATA_TYPE>
+BOOL LLLinkedQueue<DATA_TYPE>::remove(const DATA_TYPE data)
+{
+	BOOL b_found = FALSE;
+
+	LLLinkedQueueNode<DATA_TYPE> *currentp = mHead.mNextp;
+
+	while (currentp)
+	{
+		if (currentp->mData == data)
+		{
+			b_found = TRUE;
+
+			// if there is a next one, fix it
+			if (currentp->mNextp)
+			{
+				currentp->mNextp->mPrevp = currentp->mPrevp;
+			}
+			else // we are at end of list
+			{
+				mTail.mPrevp = currentp->mPrevp;
+			}
+
+			// if there is a previous one, fix it
+			if (currentp->mPrevp)
+			{
+				currentp->mPrevp->mNextp = currentp->mNextp;
+			}
+			else // we are at beginning of list
+			{
+				mHead.mNextp = currentp->mNextp;
+			}
+
+			// remove the node
+			delete currentp;
+			mLength--;
+			break;
+		}
+		currentp = currentp->mNextp; 
+	}
+
+	return b_found;
+}
+
+
+// remove all nodes from the list but do not delete associated data
+template <class DATA_TYPE>
+void LLLinkedQueue<DATA_TYPE>::reset()
+{
+	LLLinkedQueueNode<DATA_TYPE> *currentp;
+	LLLinkedQueueNode<DATA_TYPE> *nextp;
+	currentp = mHead.mNextp;
+
+	while (currentp)
+	{
+		nextp = currentp->mNextp;
+		delete currentp;
+		currentp = nextp;
+	}
+
+	// reset mHead and mCurrentp
+	mHead.mNextp = NULL;
+	mTail.mPrevp = NULL;
+	mLength = 0;
+}
+
+template <class DATA_TYPE>
+S32 LLLinkedQueue<DATA_TYPE>::getLength() const
+{
+	return mLength;
+}
+
+template <class DATA_TYPE>
+BOOL LLLinkedQueue<DATA_TYPE>::isEmpty() const
+{
+	return mLength <= 0;
+}
+
+// check to see if data is in list
+// set mCurrentp and mQueuep to the target of search if found, otherwise set mCurrentp to mQueuep
+// return TRUE if found, FALSE if not found
+template <class DATA_TYPE>
+BOOL LLLinkedQueue<DATA_TYPE>::checkData(const DATA_TYPE data) const
+{
+	LLLinkedQueueNode<DATA_TYPE> *currentp = mHead.mNextp;
+
+	while (currentp)
+	{
+		if (currentp->mData == data)
+		{
+			return TRUE;
+		}
+		currentp = currentp->mNextp;
+	}
+	return FALSE;
+}
+
+template <class DATA_TYPE>
+BOOL LLLinkedQueue<DATA_TYPE>::pop(DATA_TYPE &data)
+{
+	LLLinkedQueueNode<DATA_TYPE> *currentp;
+
+	currentp = mHead.mNextp;
+	if (!currentp)
+	{
+		return FALSE;
+	}
+
+	mHead.mNextp = currentp->mNextp;
+	if (currentp->mNextp)
+	{
+		currentp->mNextp->mPrevp = currentp->mPrevp;
+	}
+	else
+	{
+		mTail.mPrevp = currentp->mPrevp;
+	}
+
+	data = currentp->mData;
+	delete currentp;
+	mLength--;
+	return TRUE;
+}
+
+template <class DATA_TYPE>
+BOOL LLLinkedQueue<DATA_TYPE>::peek(DATA_TYPE &data)
+{
+	LLLinkedQueueNode<DATA_TYPE> *currentp;
+
+	currentp = mHead.mNextp;
+	if (!currentp)
+	{
+		return FALSE;
+	}
+	data = currentp->mData;
+	return TRUE;
+}
+
+
+//////////////////////////////////////////////////////////////////////////////////////////
+// private members
+//////////////////////////////////////////////////////////////////////////////////////////
+
+
+// add node to end of list
+// set mCurrentp to mQueuep
+template <class DATA_TYPE>
+void LLLinkedQueue<DATA_TYPE>::addNodeAtEnd(LLLinkedQueueNode<DATA_TYPE> *nodep)
+{
+	// add the node to the end of the list
+	nodep->mNextp = NULL;
+	nodep->mPrevp = mTail.mPrevp;
+	mTail.mPrevp = nodep;
+
+	// if there's something in the list, fix its back pointer
+	if (nodep->mPrevp)
+	{
+		nodep->mPrevp->mNextp = nodep;
+	}
+	else	// otherwise fix the head node
+	{
+		mHead.mNextp = nodep;
+	}
+	mLength++;
+}
+
+#endif