273 lines
4 KiB
C++
273 lines
4 KiB
C++
/*++
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Copyright (c) 2000 Microsoft Corporation
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Module Name:
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CQueue.cpp
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Abstract:
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The implementation of the C++
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Queue class.
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Notes:
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Unicode only.
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History:
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10/10/2000 a-fwills Created
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--*/
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#include "CQueue.h"
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/*++
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Routine Description:
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CQNode c'tor
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Arguments:
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lpwszString(in): Null-delimited string assigned to CQNode on
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creation, which takes place when CQueue Enqueues a string.
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Return Value:
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--*/
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CQNode::CQNode(
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LPWSTR lpwszString
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)
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{
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int nLen = wcslen(lpwszString);
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LPWSTR lpwAlloc;
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// Will be null if HeapAlloc fails. This will result in
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// FALSE return value when trying to Enqueue strings in CQueue.
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m_lpwszString = 0;
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m_pNext = 0;
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if(!(lpwAlloc = (LPWSTR)HeapAlloc(GetProcessHeap(), HEAP_ZERO_MEMORY,
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sizeof(WCHAR)*(nLen+1))))
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return;
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m_lpwszString = lpwAlloc;
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wcscpy(m_lpwszString, lpwszString);
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}
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/*++
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Routine Description:
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CQNode d'tor
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Arguments:
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None.
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Return Value:
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None.
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--*/
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CQNode::~CQNode(
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)
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{
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if(m_lpwszString)
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HeapFree(GetProcessHeap(), 0, m_lpwszString);
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}
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/*++
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Routine Description:
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CQNode copy c'tor
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Arguments:
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lpwString(out): Null delimited buffer to contain string
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enqueued contained by CQNode.
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nMaxLen(in): Maximum length available in buffer lpwString
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for copy of CQNode string. String returned will be
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null-delimited.
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Return Value:
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TRUE: CQNode successfully allocated storage for a string
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on creation (is non-null), and was able to return a
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string of zero lenght to nMaxLen length.
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FALSE: CQNode does not contain a valid storage space for
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a string to return.
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--*/
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BOOL CQNode::Copy(
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LPWSTR lpwString,
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int nMaxLen
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)
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{
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if(!m_lpwszString)
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return FALSE;
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wcsncpy(lpwString, m_lpwszString, nMaxLen);
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*(lpwString+nMaxLen) = 0;
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return TRUE;
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}
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/*++
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Routine Description:
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CQueue c'tor
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Arguments:
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None.
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Return Value:
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--*/
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CQueue::CQueue(
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)
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{
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m_cSize = 0;
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m_pHead = m_pTail = 0;
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}
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/*++
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Routine Description:
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CQeue d'tor
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Arguments:
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None.
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Return Value:
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--*/
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CQueue::~CQueue(
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)
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{
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CQNode *pQNode;
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while(m_pHead) {
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pQNode = m_pHead;
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m_pHead = m_pHead->m_pNext;
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delete pQNode;
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}
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}
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/*++
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Routine Description:
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Removes a string from the queue.
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Arguments:
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lpwString(out): buffer to contain null-delimited string
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being dequeued.
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nMaxLen(in): maximum length available for string in buffer.
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Return Value:
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TRUE: Queue is not empty and string was successfully
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returned in buffer lpwString.
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FALSE: Queue was empty. No string was returned in buffer.
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--*/
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BOOL CQueue::Dequeue(
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LPWSTR lpwString,
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int nMaxLen,
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BOOL fPersist
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)
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{
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CQNode *pQNode;
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if (fPersist) {
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pQNode = m_pHead;
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pQNode->Copy(lpwString, nMaxLen);
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} else {
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if(!m_pHead)
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return FALSE;
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pQNode = m_pHead;
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m_pHead = m_pHead->m_pNext;
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if(!m_pHead)
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m_pTail = 0;
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pQNode->Copy(lpwString, nMaxLen);
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delete pQNode;
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m_cSize--;
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}
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return TRUE;
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}
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/*++
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Routine Description:
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Adds a string to the queue.
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Arguments:
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lpwszString(in): null-delimited string to enqueue.
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Return Value:
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--*/
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BOOL CQueue::Enqueue(
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LPWSTR lpwszString
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)
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{
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CQNode *pNode = new CQNode(lpwszString), *pTail;
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pTail = pNode;
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if(m_pTail)
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m_pTail->m_pNext = pTail;
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m_pTail = pTail;
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if(!m_pHead)
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m_pHead = m_pTail;
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m_cSize++;
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return true;
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}
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/*++
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Routine Description:
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Retrives the length of the queue.
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Arguments:
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None.
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Return Value:
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The length of the current string at the head of the queue.
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Will return -1 if no strings are enqueued.
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--*/
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int CQueue::GetLength(
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)
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{
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if(!m_pHead)
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return -1;
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return m_pHead->GetLength();
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}
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