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/*
* Copyright (c) 2003-2009 Nokia Corporation and/or its subsidiary(-ies).
* All rights reserved.
* This component and the accompanying materials are made available
* under the terms of "Eclipse Public License v1.0"
* which accompanies this distribution, and is available
* at the URL "http://www.eclipse.org/legal/epl-v10.html".
*
* Initial Contributors:
* Nokia Corporation - initial contribution.
*
* Contributors:
*
* Description:
* CFixedQueue Test module
*
*/
#ifndef CFixedQueue_H
#define CFixedQueue_H
// INCLUDES
#include <e32base.h>
// CONSTANTS
_LIT(KFixedQueuePanicText, "CFixedQueue<T>");
// CLASS DECLARATION
/**
* Fixed size queue.
* @param T type of objects in the queue. T must have accessible default
* constructor and assignment operator.
*/
template<class T>
class CFixedQueue : public CBase
{
public: // Constructors and destructor
CFixedQueue();
/**
* Initializes a new fixed queue.
* @param aSize maximum size of the queue.
* @pre aSize > 0
*/
void ConstructL(TInt aSize);
/**
* Destructor.
*/
~CFixedQueue();
public: // Interface
/**
* Returns the object at the head of this queue.
* @pre !IsEmpty()
*/
T& Head() const;
/**
* Pops the head off this queue. Does not deallocate memory.
* @pre !IsEmpty()
*/
void PopHead();
/**
* Returns true if this queue is empty
*/
TBool IsEmpty() const;
/**
* Returns the number of objects in the queue.
*/
TInt Count() const;
/**
* Pushes an object at the tail of the queue.
* @return ETrue if succesful, EFalse if queue run out of space.
*/
TBool Push(const T& aObj);
/**
* Empties this queue. Does not deallocate memory.
*/
void Reset();
private: // Implementation
enum TPanicCode
{
EPanicPreCond_ConstructL = 1,
EPanicPreCond_Head,
EPanicPreCond_PopHead,
EPanicPreCond_Push,
EPanicInvariant
};
static void Panic(TPanicCode aReason);
__DECLARE_TEST;
private: // Data
/// Own: circural queue array
T* iQueueArray;
/// Own: maximum size of queue
TInt iQueueSize;
/// Own: number of objects currently in the queue
TInt iCount;
/// Ref: head of queue
T* iQueueHead;
/// Ref: tail of queue
T* iQueueTail;
};
template<class T> inline
void CFixedQueue<T>::Panic(TPanicCode aReason)
{
User::Panic(KFixedQueuePanicText,aReason);
}
template<class T> inline
CFixedQueue<T>::CFixedQueue()
{
// CBase::operator new resets memebers
__TEST_INVARIANT;
}
template<class T> inline
void CFixedQueue<T>::ConstructL(TInt aSize)
{
__TEST_INVARIANT;
__ASSERT_ALWAYS(!iQueueArray, Panic(EPanicPreCond_ConstructL));
__ASSERT_ALWAYS(aSize > 0, Panic(EPanicPreCond_ConstructL));
iQueueArray = new(ELeave) T[aSize];
iQueueSize = aSize;
iCount = 0;
iQueueHead = iQueueTail = iQueueArray;
__TEST_INVARIANT;
}
template<class T>
CFixedQueue<T>::~CFixedQueue()
{
__TEST_INVARIANT;
delete [] iQueueArray;
}
template<class T> inline
T& CFixedQueue<T>::Head() const
{
__TEST_INVARIANT;
__ASSERT_ALWAYS(iCount > 0, Panic(EPanicPreCond_Head));
return *iQueueHead;
}
template<class T> inline
void CFixedQueue<T>::PopHead()
{
__TEST_INVARIANT;
__ASSERT_ALWAYS(iCount > 0, Panic(EPanicPreCond_PopHead));
++iQueueHead;
if (iQueueHead == iQueueArray+iQueueSize)
{
iQueueHead = iQueueArray;
}
--iCount;
}
template<class T> inline
TBool CFixedQueue<T>::IsEmpty() const
{
__TEST_INVARIANT;
return (iCount==0);
}
template<class T> inline
TInt CFixedQueue<T>::Count() const
{
__TEST_INVARIANT;
return iCount;
}
template<class T> inline
TBool CFixedQueue<T>::Push(const T& aObj)
{
__TEST_INVARIANT;
if (iCount < iQueueSize)
{
*iQueueTail = aObj;
++iQueueTail;
if (iQueueTail == iQueueArray+iQueueSize)
{
iQueueTail = iQueueArray;
}
++iCount;
__TEST_INVARIANT;
return ETrue;
}
else
{
return EFalse;
}
}
template<class T> inline
void CFixedQueue<T>::Reset()
{
__TEST_INVARIANT;
iQueueTail = iQueueHead;
iCount = 0;
__TEST_INVARIANT;
}
template<class T>
void CFixedQueue<T>::__DbgTestInvariant() const
{
if (!iQueueArray)
{
// Not initialised
__ASSERT_ALWAYS(iQueueSize==0 && iCount==0, Panic(EPanicInvariant));
__ASSERT_ALWAYS(!iQueueHead && !iQueueTail, Panic(EPanicInvariant));
}
else
{
// Initialised
__ASSERT_ALWAYS(iQueueSize > 0, Panic(EPanicInvariant));
__ASSERT_ALWAYS(iCount >= 0 && iCount <= iQueueSize, Panic(EPanicInvariant));
__ASSERT_ALWAYS((iQueueHead >= iQueueArray) && (iQueueHead < iQueueArray+iQueueSize),
Panic(EPanicInvariant));
__ASSERT_ALWAYS((iQueueTail >= iQueueArray) && (iQueueTail < iQueueArray+iQueueSize),
Panic(EPanicInvariant));
}
}
#endif
// End of File
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