INSTDATA.C

/******************************************************************************\ 
*       This is a part of the Microsoft Source Code Samples.  
*       Copyright 1993 - 1998 Microsoft Corporation. 
*       All rights reserved.  
*       This source code is only intended as a supplement to  
*       Microsoft Development Tools and/or WinHelp documentation. 
*       See these sources for detailed information regarding the  
*       Microsoft samples programs. 
\******************************************************************************/ 
 
 
/****************************************************************************** 
 
                            I N S T A N C E   D A T A 
 
    Name:       instdata.c 
 
    Description: 
        This module contains functions that access instances of an object 
        type in performance data. 
 
    Functions: 
        FirstInstance 
        NextInstance 
        FindInstanceN 
        FindInstanceParent 
        InstanceName 
 
 
******************************************************************************/ 
 
#include <windows.h> 
#include <winperf.h> 
#include "perfdata.h" 
 
 
 
 
//********************************************************************* 
// 
//  FirstInstance 
// 
//      Returns pointer to the first instance of pObject type. 
//      If pObject is NULL then NULL is returned. 
// 
PPERF_INSTANCE   FirstInstance (PPERF_OBJECT pObject) 
{ 
    if (pObject) 
        return (PPERF_INSTANCE)((PCHAR) pObject + pObject->DefinitionLength); 
    else 
        return NULL; 
} 
 
 
 
 
//********************************************************************* 
// 
//  NextInstance 
// 
//      Returns pointer to the next instance following pInst. 
// 
//      If pInst is the last instance, bogus data maybe returned. 
//      The caller should do the checking. 
// 
//      If pInst is NULL, then NULL is returned. 
// 
PPERF_INSTANCE   NextInstance (PPERF_INSTANCE pInst) 
{ 
PERF_COUNTER_BLOCK *pCounterBlock; 
 
    if (pInst) 
        { 
        pCounterBlock = (PERF_COUNTER_BLOCK *)((PCHAR) pInst + pInst->ByteLength); 
        return (PPERF_INSTANCE)((PCHAR) pCounterBlock + pCounterBlock->ByteLength); 
        } 
    else 
        return NULL; 
} 
 
 
 
 
//********************************************************************* 
// 
//  FindInstanceN 
// 
//      Returns the Nth instance of pObject type.  If not found, NULL is 
//      returned.  0 <= N <= NumInstances. 
// 
 
PPERF_INSTANCE FindInstanceN (PPERF_OBJECT pObject, DWORD N) 
{ 
PPERF_INSTANCE pInst; 
DWORD          i = 0; 
 
    if (!pObject) 
        return NULL; 
    else if (N >= (DWORD)(pObject->NumInstances)) 
        return NULL; 
    else 
        { 
        pInst = FirstInstance (pObject); 
 
        while (i != N) 
            { 
            pInst = NextInstance (pInst); 
            i++; 
            } 
 
        return pInst; 
        } 
} 
 
 
 
 
//********************************************************************* 
// 
//  FindInstanceParent 
// 
//      Returns the pointer to an instance that is the parent of pInst. 
// 
//      If pInst is NULL or the parent object is not found then NULL is 
//      returned. 
// 
PPERF_INSTANCE FindInstanceParent (PPERF_INSTANCE pInst, PPERF_DATA pData) 
{ 
PPERF_OBJECT    pObject; 
 
    if (!pInst) 
        return NULL; 
    else if (!(pObject = FindObject (pData, pInst->ParentObjectTitleIndex))) 
        return NULL; 
    else 
        return FindInstanceN (pObject, pInst->ParentObjectInstance); 
} 
 
 
 
 
//********************************************************************* 
// 
//  InstanceName 
// 
//      Returns the name of the pInst. 
// 
//      If pInst is NULL then NULL is returned. 
// 
LPTSTR  InstanceName (PPERF_INSTANCE pInst) 
{ 
    if (pInst) 
        return (LPTSTR) ((PCHAR) pInst + pInst->NameOffset); 
    else 
        return NULL; 
}