90 lines
2.1 KiB
C++
90 lines
2.1 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 table for Script Manager
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File: LinkHash.h
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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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#ifndef LINKHASH_H
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#define LINKHASH_H
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#include "hashing.h"
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#include "DblLink.h"
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/* C L r u L i n k E l e m
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*
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* CLruLink is a CLinkElem with extra links to maintain a circular LRU queue
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*
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* NOTE: Both the CLinkElem list and the CDblLink lists are intrusive.
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* therefore, we need to use multiple inheritance to make sure that
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* downcasts from CLruLinkElem will work on both CLinkElem pointers
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* and CDblLink pointers. See the ARM, p. 221
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*/
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class CLruLinkElem : public CLinkElem, public CDblLink
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{
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};
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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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* CLinkHash differs from CHashTable in that it maintains some extra pointers to
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* maintain a threaded lru queue.
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*/
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class CLinkHash : public CHashTable
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{
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public:
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CLinkHash(HashFunction = DefaultHash);
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CLruLinkElem *AddElem(CLruLinkElem *pElem, BOOL fTestDups = TRUE);
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CLruLinkElem *FindElem(const void *pvKey, int cbKeyLen);
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CLruLinkElem *DeleteElem(const void *pvKey, int cbKeyLen);
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CLruLinkElem *RemoveElem(CLruLinkElem *pElem);
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// you CANNOT compare LRU nodes to NULL to know if you are at the end
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// of the list! Instead use this member.
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//
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BOOL FLruElemIsEmpty(CLruLinkElem *pElem)
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{
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pElem->AssertValid();
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return pElem == &m_lruHead;
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}
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CLruLinkElem *Begin() // return pointer to last referenced item
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{
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return static_cast<CLruLinkElem *>(m_lruHead.PNext());
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}
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CLruLinkElem *End() // return pointer to least recently accessed item
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{
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return static_cast<CLruLinkElem *>(m_lruHead.PPrev());
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}
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void AssertValid() const;
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protected:
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CDblLink m_lruHead;
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};
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#ifndef DBG
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inline void CLinkHash::AssertValid() const {}
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#endif
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#endif // LINKHASH_H
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