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//
// libavg - Media Playback Engine.
// Copyright (C) 2003-2014 Ulrich von Zadow
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2 of the License, or (at your option) any later version.
//
// This library 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
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
//
// Current versions can be found at www.libavg.de
//
#ifndef _Queue_H_
#define _Queue_H_
#include "../api.h"
#include "Exception.h"
#include <boost/thread/mutex.hpp>
#include <boost/thread/condition.hpp>
#include <boost/shared_ptr.hpp>
#include <deque>
#include <iostream>
namespace avg {
typedef boost::unique_lock<boost::mutex> unique_lock;
template<class QElement>
class AVG_TEMPLATE_API Queue
{
public:
typedef boost::shared_ptr<QElement> QElementPtr;
Queue(int maxSize=-1);
virtual ~Queue();
bool empty() const;
QElementPtr pop(bool bBlock = true);
void clear();
void push(const QElementPtr& pElem);
QElementPtr peek(bool bBlock = true) const;
int size() const;
int getMaxSize() const;
private:
QElementPtr getFrontElement(bool bBlock, unique_lock& Lock) const;
std::deque<QElementPtr> m_pElements;
mutable boost::mutex m_Mutex;
mutable boost::condition m_Cond;
int m_MaxSize;
};
template<class QElement>
Queue<QElement>::Queue(int maxSize)
: m_MaxSize(maxSize)
{
}
template<class QElement>
Queue<QElement>::~Queue()
{
}
template<class QElement>
bool Queue<QElement>::empty() const
{
unique_lock Lock(m_Mutex);
return m_pElements.empty();
}
template<class QElement>
typename Queue<QElement>::QElementPtr Queue<QElement>::pop(bool bBlock)
{
unique_lock lock(m_Mutex);
QElementPtr pElem = getFrontElement(bBlock, lock);
if (pElem) {
m_pElements.pop_front();
m_Cond.notify_one();
}
return pElem;
}
template<class QElement>
void Queue<QElement>::clear()
{
QElementPtr pElem;
do {
pElem = pop(false);
} while (pElem);
}
template<class QElement>
typename Queue<QElement>::QElementPtr Queue<QElement>::peek(bool bBlock) const
{
unique_lock lock(m_Mutex);
QElementPtr pElem = getFrontElement(bBlock, lock);
if (pElem) {
m_Cond.notify_one();
}
return pElem;
}
template<class QElement>
void Queue<QElement>::push(const QElementPtr& pElem)
{
assert(pElem);
unique_lock lock(m_Mutex);
if (m_pElements.size() == (unsigned)m_MaxSize) {
while (m_pElements.size() == (unsigned)m_MaxSize) {
m_Cond.wait(lock);
}
}
m_pElements.push_back(pElem);
m_Cond.notify_one();
}
template<class QElement>
int Queue<QElement>::size() const
{
unique_lock lock(m_Mutex);
return int(m_pElements.size());
}
template<class QElement>
int Queue<QElement>::getMaxSize() const
{
unique_lock lock(m_Mutex);
return m_MaxSize;
}
template<class QElement>
typename Queue<QElement>::QElementPtr
Queue<QElement>::getFrontElement(bool bBlock, unique_lock& lock) const
{
if (m_pElements.empty()) {
if (bBlock) {
while (m_pElements.empty()) {
m_Cond.wait(lock);
}
} else {
return QElementPtr();
}
}
return m_pElements.front();
}
}
#endif
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