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/*
* Copyright 2008 Free Software Foundation, Inc.
*
* SPDX-License-Identifier: AGPL-3.0+
*
* This software is distributed under multiple licenses; see the COPYING file in
* the main directory for licensing information for this specific distribution.
*
* This software is distributed under the terms of the GNU Affero Public License.
* See the COPYING file in the main directory for details.
*
* This use of this software may be subject to additional restrictions.
* See the LEGAL file in the main directory for details.
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU Affero General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU Affero General Public License for more details.
You should have received a copy of the GNU Affero General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef LINKEDLISTS_H
#define LINKEDLISTS_H
#include <stdlib.h>
#include <assert.h>
/** This node class is used to build singly-linked lists. */
class ListNode {
private:
ListNode* mNext;
void* mData;
public:
ListNode* next() { return mNext; }
void next(ListNode* wNext) { mNext=wNext; }
void* data() { return mData; }
void data(void* wData) { mData=wData; }
};
/** A fast FIFO for pointer-based storage. */
class PointerFIFO {
protected:
ListNode* mHead; ///< points to next item out
ListNode* mTail; ///< points to last item in
ListNode* mFreeList; ///< pool of previously-allocated nodes
unsigned mSize; ///< number of items in the FIFO
public:
PointerFIFO()
:mHead(NULL),mTail(NULL),mFreeList(NULL),
mSize(0)
{}
~PointerFIFO();
unsigned size() const { return mSize; }
unsigned totalSize() const { return 0; } // Not used in this version.
/** Put an item into the FIFO at the back of the queue. */
void put(void* val);
/** Push an item on the front of the FIFO. */
void push_front(void*val); // pat added.
/**
Take an item from the FIFO.
Returns NULL for empty list.
*/
void* get();
/** Peek at front item without removal. */
void *front() { return mHead ? mHead->data() : 0; } // pat added
private:
/** Allocate a new node to extend the FIFO. */
ListNode *allocate();
/** Release a node to the free pool after removal from the FIFO. */
void release(ListNode* wNode);
};
// This is the default type for SingleLinkList Node element;
// You can derive your class directly from this, but then you must add type casts
// all over the place.
class SingleLinkListNode
{ public:
SingleLinkListNode *mNext;
SingleLinkListNode *next() {return mNext;}
void setNext(SingleLinkListNode *item) {mNext=item;}
SingleLinkListNode() : mNext(0) {}
virtual unsigned size() { return 0; }
};
// A single-linked lists of elements with internal pointers.
// The methods must match those from SingleLinkListNode.
// This class also assumes the Node has a size() method, and accumulates
// the total size of elements in the list in totalSize().
template<class Node=SingleLinkListNode>
class SingleLinkList
{
Node *mHead, *mTail;
unsigned mSize; // Number of elements in list.
unsigned mTotalSize; // Total of size() method of elements in list.
public:
SingleLinkList() : mHead(0), mTail(0), mSize(0), mTotalSize(0) {}
unsigned size() const { return mSize; }
unsigned totalSize() const { return mTotalSize; }
Node *pop_back() { assert(0); } // Not efficient with this type of list.
Node *pop_front()
{
if (!mHead) return NULL;
Node *result = mHead;
mHead = mHead->next();
if (mTail == result) { mTail = NULL; assert(mHead == NULL); }
result->setNext(NULL); // be neat
mSize--;
mTotalSize -= result->size();
return result;
}
void push_front(Node *item)
{
item->setNext(mHead);
mHead = item;
if (!mTail) { mTail = item; }
mSize++;
mTotalSize += item->size();
}
void push_back(Node *item)
{
item->setNext(NULL);
if (mTail) { mTail->setNext(item); }
mTail = item;
if (!mHead) mHead = item;
mSize++;
mTotalSize += item->size();
}
Node *front() { return mHead; }
Node *back() { return mTail; }
// Interface to InterthreadQueue so it can used SingleLinkList as the Fifo.
void put(void *val) { push_back((Node*)val); }
void *get() { return pop_front(); }
};
#endif
// vim: ts=4 sw=4
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