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413 lines
8.0 KiB
413 lines
8.0 KiB
/*++
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Copyright (c) 1996 Microsoft Corporation
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Module Name:
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refcnt.c
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Abstract:
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This module exports Reference Counting support functions. By
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including a Reference Count Control Block (REF_CNT) in a
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dynamic type, and using this API, a Reference scheme can be
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implemented for that type.
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Author:
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Shreedhar Madhavapeddi (ShreeM) 15-March-1999
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Revision History:
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--*/
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//
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// Include Files
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//
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#include "precomp.h"
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#define EXPAND_TAG(t) ((CHAR *)(&Tag))[0],((CHAR *)(&Tag))[1],((CHAR *)(&Tag))[2],((CHAR *)(&Tag))[3]
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VOID
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ReferenceInit
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(
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IN PREF_CNT pRefCnt,
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PVOID InstanceHandle,
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VOID (*DeleteHandler)( PVOID )
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)
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/*++
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Routine Description:
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ReferenceInit initializes and adds one reference to the
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supplied Reference Control Block. If provided, an instance
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handle and delete handler are saved for use by the ReferenceRemove
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function when all references to the instance are removed.
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Arguments:
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pRefCnt - pointer to uninitialized Reference Control Block
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InstanceHandle - handle to the managed instance.
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DeleteHandler - pointer to delete function, NULL is OK.
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Return Value:
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The function's value is VOID.
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--*/
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{
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IF_DEBUG(REFCOUNTX) {
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WSPRINT(( "ReferenceInit( 0x%x, 0x%x, 0x%x )\n",
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pRefCnt, InstanceHandle, DeleteHandler ));
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}
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ASSERT( pRefCnt );
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// Set the reference to 1 and save the instance
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// handle and the delete handler.
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pRefCnt->Count = 0;
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pRefCnt->Instance = InstanceHandle;
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pRefCnt->DeleteHandler = DeleteHandler;
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#if DBG
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pRefCnt->Sig = REF_SIG;
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RtlZeroMemory(pRefCnt->Tags, sizeof(REF_TAG) * TAG_CNT);
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pRefCnt->Tags[0].Tag = 'LTOT';
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RefInitLock(pRefCnt->Lock);
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#endif
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}
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VOID
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ReferenceAdd
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(
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IN PREF_CNT pRefCnt
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)
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/*++
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Routine Description:
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Arguments:
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Return Value:
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--*/
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{
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ASSERT( pRefCnt );
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InterlockedIncrement(&pRefCnt->Count);
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IF_DEBUG(REFCOUNTX) {
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WSPRINT(( "R+%d\n", pRefCnt->Count ));
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}
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}
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VOID
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ReferenceAddCount
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(
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IN PREF_CNT pRefCnt,
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IN UINT Count
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)
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/*++
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Routine Description:
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Arguments:
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Return Value:
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--*/
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{
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ASSERT( pRefCnt->Count > 0 );
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InterlockedExchangeAdd(&pRefCnt->Count, Count);
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}
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PVOID
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ReferenceRemove
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(
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IN PREF_CNT pRefCnt
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)
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/*++
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Routine Description:
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Arguments:
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Return Value:
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--*/
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{
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UINT Count;
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UINT NoReference;
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UINT i;
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PVOID pInstance;
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ASSERT( pRefCnt );
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// Trap remove reference on a zero count
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ASSERT(pRefCnt->Count>0);
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pInstance = pRefCnt->Instance;
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//ASSERT( pRefCnt->Count > 0 );
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// If the decremented count is non zero return the instance handle
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if (InterlockedDecrement(&pRefCnt->Count) > 0 )
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{
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IF_DEBUG(REFCOUNTX) {
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WSPRINT(( "R-%d\n", pRefCnt->Count ));
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WSPRINT(( "ReferenceRemove:remaining: %d\n", pRefCnt->Count ));
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}
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#if DBG
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RefFreeLock(pRefCnt->Lock);
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#endif
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return(pInstance);
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}
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// Delete this instance if a delete handler is available
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if( pRefCnt->DeleteHandler )
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{
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#if DBG
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// sanity check
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for (i = 1; i < TAG_CNT; i++)
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{
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if ((pRefCnt->Tags[i].Tag != 0) && (pRefCnt->Tags[i].Count != 0))
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{
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IF_DEBUG(ERRORS) {
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WSPRINT(("Allors!! There is a NON-zero ref and we are deleting...\n"));
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}
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DEBUGBREAK();
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}
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}
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IF_DEBUG(REFCOUNTX) {
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WSPRINT(( "Executing DeleteHandler for %X\n", pRefCnt->Instance ));
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}
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//
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// All the Dereference* code takes the locks, so lets take it here.
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// Also, Take the global lock before releasing the ref lock.
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//
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// Time to delete the ref lock too.
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RefFreeLock(pRefCnt->Lock);
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#endif
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GetLock(pGlobals->Lock);
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#if DBG
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RefDeleteLock(pRefCnt->Lock);
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#endif
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(pRefCnt->DeleteHandler)( pRefCnt->Instance );
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FreeLock(pGlobals->Lock);
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}
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// Indicate no active references to this instance
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return( NULL );
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}
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//
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// API Test Support
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//
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#if DBG
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VOID
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ReferenceApiTest( VOID )
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{
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REF_CNT RefCnt;
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IF_DEBUG(REFCOUNTX) {
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WSPRINT(
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( "\nReferenceApiTest\n" ));
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WSPRINT(( "\nTest #1: NULL delete handler\n" ));
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}
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ReferenceInit( &RefCnt, &RefCnt, NULL );
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ReferenceAdd( &RefCnt );
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ReferenceAdd( &RefCnt );
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ReferenceAdd( &RefCnt );
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while( ReferenceRemove( &RefCnt ) )
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{
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;
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}
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IF_DEBUG(REFCOUNTX) {
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WSPRINT(( "\nTest #2: Delete Handler - TBD\n" ));
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}
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}
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VOID
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ReferenceAddDbg(PREF_CNT pRefCnt, ULONG Tag)
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{
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int i;
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int TotalPerArray = 0;
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RefGetLock(pRefCnt->Lock);
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//ASSERT(pRefCnt->Sig == REF_SIG);
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if (pRefCnt->Sig != REF_SIG) {
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DEBUGBREAK();
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}
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IF_DEBUG(REFCOUNTX) {
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WSPRINT(("TCREF: add %X (%c%c%c%c) %d\n",
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pRefCnt, EXPAND_TAG(Tag), pRefCnt->Count));
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}
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for (i = 1; i < TAG_CNT; i++)
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{
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if (pRefCnt->Tags[i].Tag == 0 || pRefCnt->Tags[i].Tag == Tag)
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{
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pRefCnt->Tags[i].Tag = Tag;
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InterlockedIncrement(&pRefCnt->Tags[i].Count);
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break;
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}
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}
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//ASSERT(i < TAG_CNT);
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if (i >= TAG_CNT) {
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DEBUGBREAK();
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}
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ReferenceAdd(pRefCnt);
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InterlockedIncrement(&pRefCnt->Tags[0].Count);
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// sanity check
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for (i = 1; i < TAG_CNT; i++)
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{
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if (pRefCnt->Tags[i].Tag != 0)
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{
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TotalPerArray += pRefCnt->Tags[i].Count;
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continue;
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}
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}
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ASSERT(TotalPerArray == pRefCnt->Tags[0].Count);
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if (TotalPerArray != pRefCnt->Tags[0].Count)
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{
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DbgBreakPoint();
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}
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RefFreeLock(pRefCnt->Lock);
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}
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VOID
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ReferenceRemoveDbg(PREF_CNT pRefCnt, ULONG Tag)
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{
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int i;
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int TotalPerArray = 0;
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BOOLEAN FoundIt = FALSE;
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RefGetLock(pRefCnt->Lock);
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if (pRefCnt->Sig != REF_SIG) {
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DEBUGBREAK();
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}
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//ASSERT(pRefCnt->Sig == REF_SIG);
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IF_DEBUG(REFCOUNTX) {
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WSPRINT(("TCREF: remove %X (%c%c%c%c) %d\n",
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pRefCnt, EXPAND_TAG(Tag), pRefCnt->Count));
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}
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for (i = 1; i < TAG_CNT; i++)
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{
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if (pRefCnt->Tags[i].Tag == Tag)
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{
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FoundIt = TRUE;
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if(pRefCnt->Tags[i].Count <= 0) {
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DEBUGBREAK();
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}
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//ASSERT(pRefCnt->Tags[i].Count > 0);
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InterlockedDecrement(&pRefCnt->Tags[i].Count);
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if (pRefCnt->Tags[i].Count == 0)
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pRefCnt->Tags[i].Tag = Tag;
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break;
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}
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}
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if (!FoundIt) {
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DEBUGBREAK();
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}
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ASSERT(FoundIt);
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ASSERT(pRefCnt->Tags[0].Count > 0);
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InterlockedDecrement(&pRefCnt->Tags[0].Count);
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// sanity check
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for (i = 1; i < TAG_CNT; i++)
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{
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if (pRefCnt->Tags[i].Tag != 0)
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{
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TotalPerArray += pRefCnt->Tags[i].Count;
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continue;
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}
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}
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ASSERT(TotalPerArray == pRefCnt->Tags[0].Count);
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if (TotalPerArray != pRefCnt->Tags[0].Count)
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{
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DbgPrint("Tag %X, RefCnt %X, perArray %d, total %d\n", Tag, pRefCnt,
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TotalPerArray, pRefCnt->Tags[0].Count);
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DbgBreakPoint();
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}
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ReferenceRemove(pRefCnt);
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}
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#endif
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