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