/*
 * Ascent MMORPG Server
 * Copyright (C) 2005-2007 Ascent Team <http://www.ascentemu.com/>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

#ifndef _FASTQUEUE_H
#define _FASTQUEUE_H

/** dummy lock to use a non-locked queue.
 */
class DummyLock
{
public:
	inline void Acquire() { }
	inline void Release() { }
};

/** linked-list style queue
 */
template<class T, class LOCK>
class FastQueue
{
	struct node
	{
		T element;
		node * next;
	};

	node * last;
	node * first;
	LOCK m_lock;

public:

	FastQueue()
	{
		last = 0;
		first = 0;
	}

	~FastQueue()
	{
		Clear();
	}

	void Clear()
	{
		// clear any elements
		while(last != 0)
			Pop();
	}

	void Push(T elem)
	{
		m_lock.Acquire();
		node * n = new node;
		if(last)
			last->next = n;
		else
			first = n;

		last = n;
		n->next = 0;
		n->element = elem;
		m_lock.Release();
	}

	T Pop()
	{
		m_lock.Acquire();
		if(first == 0)
		{
			m_lock.Release();
			return reinterpret_cast<T>(0);
		}
        
		T ret = first->element;
		node * td = first;
		first = td->next;
		if(!first)
			last = 0;

		delete td;
		m_lock.Release();
		return ret;
	}

	T front()
	{
		m_lock.Acquire();
		if(first == 0)
		{
			m_lock.Release();
			return reinterpret_cast<T>(0);
		}

		T ret = first->element;
		m_lock.Release();
		return ret;
	}

	void pop_front()
	{
		m_lock.Acquire();
		if(first == 0)
		{
			m_lock.Release();
			return;
		}

		node * td = first;
		first = td->next;
		if(!first)
			last = 0;

		delete td;
		m_lock.Release();
	}

	inline bool HasItems()
	{
		bool ret;
		m_lock.Acquire();
		ret = (first != 0);
		m_lock.Release();
		return ret;
	}
};

#endif