111 lines
2 KiB
C++
111 lines
2 KiB
C++
/*++
|
|
|
|
Copyright (C) 1996-2001 Microsoft Corporation
|
|
|
|
Module Name:
|
|
|
|
FLEXQ.CPP
|
|
|
|
Abstract:
|
|
|
|
CFlexQueue.
|
|
|
|
History:
|
|
|
|
--*/
|
|
|
|
#include "precomp.h"
|
|
//#include <dbgalloc.h>
|
|
#include <flexq.h>
|
|
|
|
CFlexQueue::CFlexQueue(int nInitialSize) :
|
|
m_nSize(nInitialSize), m_nHeadIndex(0), m_nTailIndex(0)
|
|
{
|
|
if(m_nSize)
|
|
m_ppData = new void*[m_nSize];
|
|
else
|
|
m_ppData = NULL;
|
|
}
|
|
|
|
CFlexQueue::~CFlexQueue()
|
|
{
|
|
delete [] m_ppData;
|
|
}
|
|
|
|
bool CFlexQueue::Grow()
|
|
{
|
|
int nNewSize = (m_nSize + 1) * 2;
|
|
|
|
// Allocate new memory block
|
|
// =========================
|
|
|
|
void** ppNewData = new void*[nNewSize];
|
|
if(ppNewData == NULL)
|
|
return false;
|
|
|
|
// Copy the queue data to the beginning of the array
|
|
// =================================================
|
|
|
|
if(m_nHeadIndex <= m_nTailIndex)
|
|
{
|
|
memcpy(ppNewData, m_ppData + m_nHeadIndex,
|
|
(m_nTailIndex - m_nHeadIndex) * sizeof(void*));
|
|
}
|
|
else
|
|
{
|
|
memcpy(ppNewData, m_ppData + m_nHeadIndex,
|
|
(m_nSize - m_nHeadIndex) * sizeof(void*));
|
|
memcpy(ppNewData + (m_nSize - m_nHeadIndex), m_ppData,
|
|
m_nTailIndex * sizeof(void*));
|
|
}
|
|
|
|
m_nTailIndex = GetQueueSize();
|
|
m_nHeadIndex = 0;
|
|
m_nSize = nNewSize;
|
|
delete [] m_ppData;
|
|
m_ppData = ppNewData;
|
|
|
|
return true;
|
|
}
|
|
|
|
bool CFlexQueue::Enqueue(void* pNew)
|
|
{
|
|
if(GetQueueSize() >= m_nSize - 1)
|
|
{
|
|
if(!Grow()) return false;
|
|
}
|
|
|
|
m_ppData[m_nTailIndex] = pNew;
|
|
IncrementIndex(m_nTailIndex);
|
|
return true;
|
|
}
|
|
|
|
void* CFlexQueue::Dequeue()
|
|
{
|
|
if(GetQueueSize() == 0)
|
|
return NULL;
|
|
void* pRet = m_ppData[m_nHeadIndex];
|
|
IncrementIndex(m_nHeadIndex);
|
|
return pRet;
|
|
}
|
|
|
|
void* CFlexQueue::Peek()
|
|
{
|
|
if(GetQueueSize() == 0)
|
|
return NULL;
|
|
return m_ppData[m_nHeadIndex];
|
|
}
|
|
|
|
|
|
bool CFlexQueue::Requeue(void* pNew)
|
|
{
|
|
if(GetQueueSize() >= m_nSize - 1)
|
|
{
|
|
if(!Grow()) return false;
|
|
}
|
|
|
|
DecrementIndex(m_nHeadIndex);
|
|
m_ppData[m_nHeadIndex] = pNew;
|
|
return true;
|
|
}
|