90 lines
2.4 KiB
C++
90 lines
2.4 KiB
C++
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/**********************************************************************/
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/** Microsoft Windows NT **/
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/** Copyright(c) Microsoft Corp., 1994 **/
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/**********************************************************************/
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/*
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blobhash.hxx
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This module defines the classes used for storing blob
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objects in a hash table.
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FILE HISTORY:
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MCourage 09-Dec-1997 Created
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*/
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#include <lkrhash.h>
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#include <mbstring.h>
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class CBlobKey {
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public:
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CHAR * m_pszPathName; // The path name in upper-case
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DWORD m_cbPathName; // The number of bytes in the path name
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DWORD m_dwService; // Service ID
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DWORD m_dwInstance; // Instance ID
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DWORD m_dwDemux; // Type of object
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};
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class CBlobHashTable
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: public CTypedHashTable<CBlobHashTable, BLOB_HEADER, const CBlobKey*>
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{
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public:
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CBlobHashTable(
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LPCSTR pszName)
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: CTypedHashTable<CBlobHashTable, BLOB_HEADER, const CBlobKey*>(pszName)
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{}
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static const CBlobKey *
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ExtractKey(const BLOB_HEADER *pBlob)
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{
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return pBlob->pBlobKey;
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}
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static DWORD
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CalcKeyHash(const CBlobKey * blobKey)
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{
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DWORD dw = Hash(blobKey->m_dwService)
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+ 37 * Hash(blobKey->m_dwInstance)
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+ 61 * Hash(blobKey->m_dwDemux);
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// use the last 16 chars of the pathname
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// this gives a good distribution
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const CHAR * psz = blobKey->m_pszPathName;
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if (blobKey->m_cbPathName > 80)
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psz += blobKey->m_cbPathName - 80;
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return HashString(psz, dw * blobKey->m_cbPathName);
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}
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static bool
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EqualKeys(const CBlobKey * blobKey1, const CBlobKey * blobKey2)
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{
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if ((blobKey1->m_dwService == blobKey2->m_dwService) &&
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(blobKey1->m_dwInstance == blobKey2->m_dwInstance) &&
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(blobKey1->m_dwDemux == blobKey2->m_dwDemux) &&
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(blobKey1->m_cbPathName == blobKey2->m_cbPathName) &&
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(memcmp(blobKey1->m_pszPathName,
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blobKey2->m_pszPathName,
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blobKey2->m_cbPathName) == 0)) {
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return TRUE;
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} else {
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return FALSE;
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}
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}
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static void
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AddRefRecord(BLOB_HEADER * pBlob, int nIncr)
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{
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DBG_ASSERT( nIncr == +1 || nIncr == -1 );
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if (nIncr == +1) {
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pBlob->AddRef();
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} else {
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pBlob->Deref();
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}
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}
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};
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