Source code of Windows XP (NT5)
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/*===================================================================
Microsoft Denali
Microsoft Confidential.
Copyright 1996 Microsoft Corporation. All Rights Reserved.
Component: Hash tables with LRU threading
File: LinkHash.cpp
Owner: DGottner
This is the Link list and Hash table for use by any classes which
also need LRU access to items. (This includes cache manager,
script manager, and session deletion code)
===================================================================*/
#include "denpre.h"
#pragma hdrstop
#include "LinkHash.h"
#include "memchk.h"
/*------------------------------------------------------------------
* C L i n k H a s h
*/
/*===================================================================
CLinkHash::CLinkHash
Constructor for CLinkHash
Parameters:
NONE
Returns:
NONE
===================================================================*/
CLinkHash::CLinkHash( HashFunction pfnHash )
: CHashTable( pfnHash )
{
}
/*===================================================================
CLinkHash::AddElem
Parameters:
pElem - item to add to the table. The item is marked as the most
recently accessed.
Returns:
Returns a pointer to the item added
===================================================================*/
CLruLinkElem *CLinkHash::AddElem(CLruLinkElem *pElem, BOOL fTestDups)
{
AssertValid();
CLruLinkElem *pElemAdded = static_cast<CLruLinkElem *>(CHashTable::AddElem(pElem, fTestDups));
pElemAdded->PrependTo(m_lruHead);
AssertValid();
return pElemAdded;
}
/*===================================================================
CLinkHash::FindElem
Parameters:
pvKey - pointer to the key to insert
cbKey - number of bytes in the key
Returns:
NULL if the key is not in the hash table, otherwise it returns
a pointer to the key's record. If the key is found, it is
moved to the front of the list.
===================================================================*/
CLruLinkElem *CLinkHash::FindElem(const void *pvKey, int cbKey)
{
AssertValid();
CLruLinkElem *pElemFound = static_cast<CLruLinkElem *>(CHashTable::FindElem(pvKey, cbKey));
if (pElemFound)
{
pElemFound->PrependTo(m_lruHead);
AssertValid();
}
return pElemFound;
}
/*===================================================================
CLinkHash::DeleteElem
Parameters:
pvKey - pointer to the key to delete
cbKey - number of bytes in the key
Returns:
NULL if the key is not in the hash table, otherwise it returns
a pointer to the key's record. If the key is found, it is
removed from the hash table and the LRU list.
===================================================================*/
CLruLinkElem *CLinkHash::DeleteElem(const void *pvKey, int cbKey)
{
AssertValid();
CLruLinkElem *pElemFound = static_cast<CLruLinkElem *>(CHashTable::DeleteElem(pvKey, cbKey));
if (pElemFound)
pElemFound->UnLink();
AssertValid();
return pElemFound;
}
/*===================================================================
CLinkHash::RemoveElem
Parameters:
pvKey - pointer to the key to delete
cbKey - number of bytes in the key
Returns:
NULL if the key is not in the hash table, otherwise it returns
a pointer to the key's record. If the key is found, it is
removed from the hash table and the LRU list.
===================================================================*/
CLruLinkElem *CLinkHash::RemoveElem(CLruLinkElem *pElem)
{
AssertValid();
CLruLinkElem *pElemRemoved = static_cast<CLruLinkElem *>(CHashTable::RemoveElem(pElem));
Assert (pElemRemoved);
pElemRemoved->UnLink();
AssertValid();
return pElemRemoved;
}
/*===================================================================
CLinkHash::AssertValid
verify the integrity of the data structure
===================================================================*/
#ifdef DBG
void CLinkHash::AssertValid() const
{
// NOTE: avoid calling CHashTable::AssertValid as long as hash table primitives are calling it.
// CHashTable::AssertValid();
m_lruHead.AssertValid();
for (CDblLink *pLink = m_lruHead.PNext(); pLink != &m_lruHead; pLink = pLink->PNext())
pLink->AssertValid();
}
#endif