/*++

Copyright (C) 1995-1999 Microsoft Corporation

Module Name:

    calcfuns.c

Abstract:

    Counter calculation functions
    WMICOOKER.DLL depends on this file also. \nt\admin\wmi\wbem\winmgmt\wmicooker

--*/

#include <windows.h>
#include <math.h>
#include "strsafe.h"
#include <pdh.h>
#include "pdhitype.h"
#include "pdhidef.h"
#include "pdhicalc.h"
#include "pdhmsg.h"

BOOL
AssignCalcFunction(
    DWORD           dwCounterType,
    LPCOUNTERCALC * pCalcFunc,
    LPCOUNTERSTAT * pStatFunc
)
{
    BOOL bReturn = TRUE;

    // reset the last error value
    SetLastError(ERROR_SUCCESS);

    if (pCalcFunc == NULL || pStatFunc == NULL) {
        SetLastError(PDH_INVALID_ARGUMENT);
        bReturn = FALSE;
    }
    else {
        __try {
            * pCalcFunc = PdhiCalcNoData;
            * pStatFunc = PdhiComputeNoDataStats;
        }
        except (EXCEPTION_EXECUTE_HANDLER) {
            bReturn = FALSE;
        }
    }
    if (bReturn) {
        switch (dwCounterType) {
        case PERF_DOUBLE_RAW:
            * pCalcFunc = PdhiCalcDouble;
            * pStatFunc = PdhiComputeRawCountStats;
            break;

        case PERF_AVERAGE_TIMER:
            * pCalcFunc = PdhiCalcAverage;
            * pStatFunc = PdhiComputeFirstLastStats;
            break;

        case PERF_ELAPSED_TIME:
            * pCalcFunc = PdhiCalcElapsedTime;
            * pStatFunc = PdhiComputeRawCountStats;
            break;

        case PERF_RAW_FRACTION:
        case PERF_LARGE_RAW_FRACTION:
            * pCalcFunc = PdhiCalcRawFraction;
            * pStatFunc = PdhiComputeRawCountStats;
            break;

        case PERF_COUNTER_COUNTER:
        case PERF_COUNTER_BULK_COUNT:
        case PERF_SAMPLE_COUNTER:
            * pCalcFunc = PdhiCalcCounter;
            * pStatFunc = PdhiComputeFirstLastStats;
            break;

        case PERF_AVERAGE_BULK:
        case PERF_COUNTER_TIMER:
        case PERF_100NSEC_TIMER:
        case PERF_OBJ_TIME_TIMER:
        case PERF_COUNTER_QUEUELEN_TYPE:
        case PERF_COUNTER_LARGE_QUEUELEN_TYPE:
        case PERF_COUNTER_100NS_QUEUELEN_TYPE:
        case PERF_COUNTER_OBJ_TIME_QUEUELEN_TYPE:
        case PERF_SAMPLE_FRACTION:
        case PERF_COUNTER_MULTI_TIMER:
        case PERF_100NSEC_MULTI_TIMER:
        case PERF_PRECISION_SYSTEM_TIMER:
        case PERF_PRECISION_100NS_TIMER:
        case PERF_PRECISION_OBJECT_TIMER:
            * pCalcFunc = PdhiCalcTimer;
            * pStatFunc = PdhiComputeFirstLastStats;
            break;

        case PERF_COUNTER_TIMER_INV:
        case PERF_100NSEC_TIMER_INV:
        case PERF_COUNTER_MULTI_TIMER_INV:
        case PERF_100NSEC_MULTI_TIMER_INV:
            * pCalcFunc = PdhiCalcInverseTimer;
            * pStatFunc = PdhiComputeFirstLastStats;
            break;

        case PERF_COUNTER_RAWCOUNT:
        case PERF_COUNTER_LARGE_RAWCOUNT:
        case PERF_COUNTER_RAWCOUNT_HEX:
        case PERF_COUNTER_LARGE_RAWCOUNT_HEX:
            * pCalcFunc = PdhiCalcRawCounter;
            * pStatFunc = PdhiComputeRawCountStats;
            break;

        case PERF_COUNTER_DELTA:
        case PERF_COUNTER_LARGE_DELTA:
            * pCalcFunc = PdhiCalcDelta;
            * pStatFunc = PdhiComputeRawCountStats;
            break;

        case PERF_COUNTER_TEXT:
        case PERF_SAMPLE_BASE:
        case PERF_AVERAGE_BASE:
        case PERF_COUNTER_MULTI_BASE:
        case PERF_RAW_BASE:
        //case PERF_LARGE_RAW_BASE:
        case PERF_COUNTER_HISTOGRAM_TYPE:
        case PERF_COUNTER_NODATA:
        case PERF_PRECISION_TIMESTAMP:
            * pCalcFunc = PdhiCalcNoData;
            * pStatFunc = PdhiComputeNoDataStats;
            break;

        default:
            // an unrecognized counter type. Define the function, but
            // return false.
            * pCalcFunc = PdhiCalcNoData;
            * pStatFunc = PdhiComputeNoDataStats;
            SetLastError(PDH_FUNCTION_NOT_FOUND);
            bReturn = FALSE;
            break;
        }
    }
    return bReturn;
}

BOOL
PdhiCounterNeedLastValue(
    DWORD  dwCounterType
)
{
    BOOL bReturn = TRUE;
    switch (dwCounterType) {
    case PERF_DOUBLE_RAW:
    case PERF_ELAPSED_TIME:
    case PERF_RAW_FRACTION:
    case PERF_LARGE_RAW_FRACTION:
    case PERF_COUNTER_RAWCOUNT:
    case PERF_COUNTER_LARGE_RAWCOUNT:
    case PERF_COUNTER_RAWCOUNT_HEX:
    case PERF_COUNTER_LARGE_RAWCOUNT_HEX:
    case PERF_COUNTER_TEXT:
    case PERF_SAMPLE_BASE:
    case PERF_AVERAGE_BASE:
    case PERF_COUNTER_MULTI_BASE:
    case PERF_RAW_BASE:
    //case PERF_LARGE_RAW_BASE:
    case PERF_COUNTER_HISTOGRAM_TYPE:
    case PERF_COUNTER_NODATA:
    case PERF_PRECISION_TIMESTAMP:
        bReturn = FALSE;
        break;

    case PERF_AVERAGE_TIMER:
    case PERF_COUNTER_COUNTER:
    case PERF_COUNTER_BULK_COUNT:
    case PERF_SAMPLE_COUNTER:
    case PERF_AVERAGE_BULK:
    case PERF_COUNTER_TIMER:
    case PERF_100NSEC_TIMER:
    case PERF_OBJ_TIME_TIMER:
    case PERF_COUNTER_QUEUELEN_TYPE:
    case PERF_COUNTER_LARGE_QUEUELEN_TYPE:
    case PERF_COUNTER_100NS_QUEUELEN_TYPE:
    case PERF_COUNTER_OBJ_TIME_QUEUELEN_TYPE:
    case PERF_SAMPLE_FRACTION:
    case PERF_COUNTER_MULTI_TIMER:
    case PERF_100NSEC_MULTI_TIMER:
    case PERF_PRECISION_SYSTEM_TIMER:
    case PERF_PRECISION_100NS_TIMER:
    case PERF_PRECISION_OBJECT_TIMER:
    case PERF_COUNTER_TIMER_INV:
    case PERF_100NSEC_TIMER_INV:
    case PERF_COUNTER_MULTI_TIMER_INV:
    case PERF_100NSEC_MULTI_TIMER_INV:
    case PERF_COUNTER_DELTA:
    case PERF_COUNTER_LARGE_DELTA:

    default:
        bReturn = TRUE;
        break;
    }

    return bReturn;
}

double
APIENTRY
PdhiCalcDouble(
    PPDH_RAW_COUNTER   pThisValue,
    PPDH_RAW_COUNTER   pLastValue,
    LONGLONG         * pllTimeBase,
    LPDWORD            pdwStatus
)
{
    double  dReturn;
    DWORD   dwStatus;

    UNREFERENCED_PARAMETER(pLastValue);
    UNREFERENCED_PARAMETER(pllTimeBase);

    dReturn = * (DOUBLE *) & pThisValue->FirstValue;

    if (dReturn < 0) {
        dReturn  = 0.0f;
        dwStatus = PDH_CSTATUS_INVALID_DATA;
    }
    else {
        dwStatus = pThisValue->CStatus;
    }
    if (pdwStatus != NULL) {
        * pdwStatus = dwStatus;
    }
    return dReturn;
}

double
APIENTRY
PdhiCalcAverage(
    PPDH_RAW_COUNTER   pThisValue,
    PPDH_RAW_COUNTER   pLastValue,
    LONGLONG         * pllTimeBase,
    LPDWORD            pdwStatus
)
{
    LONGLONG llNumDiff;
    LONGLONG llDenDiff = 0;
    double   dNum;
    double   dDen;
    double   dReturn   = 0.0f;
    DWORD    dwStatus  = PDH_CSTATUS_VALID_DATA;

    // test access to the required second parameter (lastValue)
    __try {
        if (pLastValue != NULL) {
            if (IsSuccessSeverity(pLastValue->CStatus)) {
                llDenDiff = pThisValue->SecondValue - pLastValue->SecondValue;
            }
            else {
                dwStatus = pLastValue->CStatus;
            }
        }
        else {
            dwStatus = PDH_CSTATUS_INVALID_DATA;
        }
    }
    __except (EXCEPTION_EXECUTE_HANDLER) {
        dwStatus = PDH_INVALID_ARGUMENT;
    }

    if (dwStatus == PDH_CSTATUS_VALID_DATA) {
        if ((llDenDiff > 0) && (* pllTimeBase > 0)) {
            llNumDiff = pThisValue->FirstValue - pLastValue->FirstValue;
            if (llNumDiff < 0) {
                llNumDiff += MAXDWORD;
            }
            if (llNumDiff > 0) {
                dNum    = (double) llNumDiff;
                dNum   /= (double) * pllTimeBase;
                dDen    = (double) llDenDiff;
                dReturn = (dNum / dDen);
            }
            else if (llNumDiff < 0) {
                dwStatus = PDH_CALC_NEGATIVE_VALUE;
            }
        }
        else {
            if (llDenDiff < 0) {
                dwStatus = PDH_CALC_NEGATIVE_DENOMINATOR;
            }
            else if (* pllTimeBase < 0) {
                dwStatus = PDH_CALC_NEGATIVE_TIMEBASE;
            }
        }
    }
    if (pdwStatus != NULL) {
        * pdwStatus = dwStatus;
    }
    return dReturn;
}

double
APIENTRY
PdhiCalcElapsedTime(
    PPDH_RAW_COUNTER   pThisValue,
    PPDH_RAW_COUNTER   pLastValue,
    LONGLONG         * pllTimeBase,
    LPDWORD            pdwStatus
)
{
    LONGLONG llDiff;
    double   dReturn  = 0.0f;
    DWORD    dwStatus = PDH_CSTATUS_VALID_DATA;

    UNREFERENCED_PARAMETER(pLastValue);
    // test access to the required second parameter (lastValue)
    __try {
        if (IsSuccessSeverity(pThisValue->CStatus)) {
            llDiff = pThisValue->SecondValue - pThisValue->FirstValue;
        }
        else {
            dwStatus = pThisValue->CStatus;
        }
    }
    __except (EXCEPTION_EXECUTE_HANDLER) {
        dwStatus = PDH_INVALID_ARGUMENT;
    }

    if (dwStatus == PDH_CSTATUS_VALID_DATA) {
        if (* pllTimeBase > 0) {
            llDiff = pThisValue->SecondValue - pThisValue->FirstValue;
            if (llDiff > 0) {
                dReturn  = (double) llDiff;
                dReturn /= (double) * pllTimeBase;
            }
            else {
                if (llDiff < 0) {
                    dwStatus = PDH_CALC_NEGATIVE_DENOMINATOR;
                }
            }
        }
        else {
            if (* pllTimeBase < 0) {
                dwStatus = PDH_CALC_NEGATIVE_TIMEBASE;
            }
        }
    }
    if (pdwStatus != NULL) {
        * pdwStatus = dwStatus;
    }
    return dReturn;
}

double
APIENTRY
PdhiCalcRawFraction(
    PPDH_RAW_COUNTER   pThisValue,
    PPDH_RAW_COUNTER   pLastValue,
    LONGLONG         * pllTimeBase,
    LPDWORD            pdwStatus
)
{
    LONGLONG llDen;
    double   dReturn  = 0.0f;
    DWORD    dwStatus = PDH_CSTATUS_VALID_DATA;

    UNREFERENCED_PARAMETER(pLastValue);
    UNREFERENCED_PARAMETER(pllTimeBase);

    if ((llDen = pThisValue->SecondValue) > 0) {
        dReturn  = (double)(pThisValue->FirstValue);
        dReturn /= (double)llDen;
    }
    else {
        if (llDen < 0) {
            dwStatus = PDH_CALC_NEGATIVE_DENOMINATOR;
        }
        dReturn = (double)0.0;
    }
    if (pdwStatus != NULL) {
        * pdwStatus = dwStatus;
    }
    return dReturn;
}

double
APIENTRY
PdhiCalcCounter(
    PPDH_RAW_COUNTER   pThisValue,
    PPDH_RAW_COUNTER   pLastValue,
    LONGLONG         * pllTimeBase,
    LPDWORD            pdwStatus
)
{
    LONGLONG llNumDiff;
    LONGLONG llDenDiff = 0;
    double   dNum;
    double   dDen;
    double   dReturn   = 0.0f;
    double   dMulti;
    DWORD    dwStatus  = PDH_CSTATUS_VALID_DATA;

    // test access to the required second parameter (lastValue)
    __try {
        if (pLastValue != NULL) {
            if (IsSuccessSeverity(pLastValue->CStatus)) {
                llDenDiff = pThisValue->SecondValue - pLastValue->SecondValue;
            }
            else {
                dwStatus = pLastValue->CStatus;
            }
        }
        else {
            dwStatus = PDH_CSTATUS_INVALID_DATA;
        }
    }
    __except (EXCEPTION_EXECUTE_HANDLER) {
        dwStatus = PDH_INVALID_ARGUMENT;
    }

    if (dwStatus == PDH_CSTATUS_VALID_DATA) {
        if ((llDenDiff > 0) && (* pllTimeBase)) {
            llNumDiff = pThisValue->FirstValue - pLastValue->FirstValue;
            if (llNumDiff < 0) {
                llNumDiff += MAXDWORD;
            }
            if (llNumDiff > 0) {
                dNum    = (double) llNumDiff;
                dDen    = (double) llDenDiff;
                dDen   /= (double) * pllTimeBase;
                dReturn = (dNum / dDen);
                if (pThisValue->MultiCount > 1) {
                    // don't do this if the count is <= 1
                    dMulti   = (double) pThisValue->FirstValue;
                    dReturn /= dMulti;
                }
            }
            else if (llNumDiff < 0) {
                dwStatus = PDH_CALC_NEGATIVE_VALUE;
            }
        }
        else {
            if (llDenDiff < 0) {
                dwStatus = PDH_CALC_NEGATIVE_DENOMINATOR;
            }
            else if (* pllTimeBase < 0) {
                dwStatus = PDH_CALC_NEGATIVE_TIMEBASE;
            }
        }
    }
    if (pdwStatus != NULL) {
        * pdwStatus = dwStatus;
    }
    return dReturn;
}

double
APIENTRY
PdhiCalcTimer(
    PPDH_RAW_COUNTER   pThisValue,
    PPDH_RAW_COUNTER   pLastValue,
    LONGLONG         * pllTimeBase,
    LPDWORD            pdwStatus
)
{
    LONGLONG llNumDiff;
    LONGLONG llDenDiff = 0;
    double   dReturn   = 0.0f;
    DWORD    dwStatus  = PDH_CSTATUS_VALID_DATA;

    UNREFERENCED_PARAMETER(pllTimeBase);

    // test access to the required second parameter (lastValue)
    __try {
        if (pLastValue != NULL) {
            if (IsSuccessSeverity(pLastValue->CStatus)) {
                llDenDiff = pThisValue->SecondValue - pLastValue->SecondValue;
            }
            else {
                dwStatus = pLastValue->CStatus;
            }
        }
        else {
            // the last value wasn't passed in
            dwStatus = PDH_CSTATUS_INVALID_DATA;
        }
    }
    __except (EXCEPTION_EXECUTE_HANDLER) {
        dwStatus = PDH_INVALID_ARGUMENT;
    }

    if (dwStatus == PDH_CSTATUS_VALID_DATA) {
        if (llDenDiff > 0) {
            llNumDiff = pThisValue->FirstValue - pLastValue->FirstValue;
            if (llNumDiff < 0) {
                llNumDiff += MAXDWORD;
            }
            if (llNumDiff > 0) {
                dReturn  = (double) llNumDiff;
                dReturn /= (double) llDenDiff;
                if (pThisValue->MultiCount > 1) {
                    // don't do this if the count is <= 1
                    dReturn /= (double)pThisValue->MultiCount;
                }
            }
            else if (llNumDiff < 0) {
                dwStatus = PDH_CALC_NEGATIVE_VALUE;
            }
        }
        else {
            if (llDenDiff < 0) {
                dwStatus = PDH_CALC_NEGATIVE_DENOMINATOR;
            }
        }
    }
    if (pdwStatus != NULL) {
        * pdwStatus = dwStatus;
    }
    return dReturn;
}

double
APIENTRY
PdhiCalcInverseTimer(
    PPDH_RAW_COUNTER   pThisValue,
    PPDH_RAW_COUNTER   pLastValue,
    LONGLONG         * pllTimeBase,
    LPDWORD            pdwStatus
)
{
    LONGLONG llNumDiff;
    LONGLONG llDenDiff = 0;
    double   dReturn   = 0.0f;
    double   dNumDiff, dDenDiff;
    double   dRatio;
    DWORD    dwStatus  = PDH_CSTATUS_VALID_DATA;

    UNREFERENCED_PARAMETER(pllTimeBase);
    // test access to the required second parameter (lastValue)
    __try {
        if (pLastValue != NULL) {
            if (IsSuccessSeverity(pLastValue->CStatus)) {
                llDenDiff = pThisValue->SecondValue - pLastValue->SecondValue;
            }
            else {
                dwStatus = pLastValue->CStatus;
            }
        }
        else {
            dwStatus = PDH_CSTATUS_INVALID_DATA;
        }
    }
    __except (EXCEPTION_EXECUTE_HANDLER) {
        dwStatus = PDH_INVALID_ARGUMENT;
    }
    if (dwStatus == PDH_CSTATUS_VALID_DATA) {
        if (llDenDiff > 0) {
            llNumDiff = pThisValue->FirstValue - pLastValue->FirstValue;
            if (llNumDiff < 0) {
                llNumDiff += MAXDWORD;
            }
            if (llNumDiff >= 0) {
                dNumDiff  = (double)llNumDiff;
                dDenDiff  = (double)llDenDiff;
                dRatio    = dNumDiff;
                dRatio   /= dDenDiff;
                if (pThisValue->MultiCount <= 1) {
                    dReturn = (double) 1.0;
                }
                else {
                    dReturn = (double) pThisValue->MultiCount;
                }
                // subtract the result from the multi count to get the
                // "inverse" time
                dReturn -= dRatio;

                if (dReturn < (double) 0.0) {
                    // allow a "fudge" factor before reporting errors
                    if (dReturn < (double) (-0.1)) {
                        dwStatus = PDH_CALC_NEGATIVE_DENOMINATOR;
                    }
                    dReturn = (double) 0.0;
                }
            }
            else if (llNumDiff < 0) {
                dwStatus = PDH_CALC_NEGATIVE_VALUE;
            }
        }
        else {
            if (llDenDiff < 0) {
                dwStatus = PDH_CALC_NEGATIVE_DENOMINATOR;
            }
            dReturn = (double) 0.0;
        }
    }
    if (pdwStatus != NULL) {
        * pdwStatus = dwStatus;
    }
    return dReturn;
}

double
APIENTRY
PdhiCalcRawCounter(
    PPDH_RAW_COUNTER   pThisValue,
    PPDH_RAW_COUNTER   pLastValue,
    LONGLONG         * pllTimeBase,
    LPDWORD            pdwStatus
)
{
    UNREFERENCED_PARAMETER(pLastValue);
    UNREFERENCED_PARAMETER(pllTimeBase);
    if (pdwStatus != NULL) {
        * pdwStatus = pThisValue->CStatus;
    }
    return (double) pThisValue->FirstValue;
}

double
APIENTRY
PdhiCalcNoData(
    PPDH_RAW_COUNTER   pThisValue,
    PPDH_RAW_COUNTER   pLastValue,
    LONGLONG         * pllTimeBase,
    LPDWORD            pdwStatus
)
{
    UNREFERENCED_PARAMETER(pThisValue);
    UNREFERENCED_PARAMETER(pLastValue);
    UNREFERENCED_PARAMETER(pllTimeBase);
    if (pdwStatus != NULL) {
        * pdwStatus = PDH_NO_DATA;
    }
    return (double) 0.0;
}

double
APIENTRY
PdhiCalcDelta(
    PPDH_RAW_COUNTER   pThisValue,
    PPDH_RAW_COUNTER   pLastValue,
    LONGLONG         * pllTimeBase,
    LPDWORD            pdwStatus
)
{
    LONGLONG llNumDiff = 0;
    double   dReturn   = 0.0f;
    DWORD    dwStatus  = PDH_CSTATUS_VALID_DATA;

    UNREFERENCED_PARAMETER(pllTimeBase);
    // test access to the required second parameter (lastValue)
    __try {
        if (pLastValue != NULL) {
            if (IsSuccessSeverity(pLastValue->CStatus)) {
                llNumDiff = pThisValue->FirstValue - pLastValue->FirstValue;
            }
            else {
                dwStatus = pLastValue->CStatus;
            }
        }
        else {
            dwStatus = PDH_CSTATUS_INVALID_DATA;
        }
    }
    __except (EXCEPTION_EXECUTE_HANDLER) {
        dwStatus = PDH_INVALID_ARGUMENT;
    }

    if (dwStatus == PDH_CSTATUS_VALID_DATA) {
        if (llNumDiff < 0) {
            llNumDiff += MAXDWORD;
        }
        if (llNumDiff < 0) {
            dwStatus = PDH_CALC_NEGATIVE_VALUE;
            dReturn  = (double) 0.0;
        }
        else {
            dReturn = (double)llNumDiff;
        }
    }
    if (pdwStatus != NULL) {
        * pdwStatus = dwStatus;
    }
    return dReturn;
}

PDH_STATUS
PdhiComputeFormattedValue(
    LPCOUNTERCALC         pCalcFunc,
    DWORD                 dwCounterType,
    LONG                  lScale,
    DWORD                 dwFormat,
    PPDH_RAW_COUNTER      pRawValue1,
    PPDH_RAW_COUNTER      pRawValue2,
    PLONGLONG             pTimeBase,
    DWORD                 dwReserved,
    PPDH_FMT_COUNTERVALUE pValue
)
{
    double     dResult = (double)0.0;
    double     dScale;
    PDH_STATUS lStatus = ERROR_SUCCESS;
    DWORD      dwValueStatus = PDH_CSTATUS_VALID_DATA;

    UNREFERENCED_PARAMETER(dwReserved);

    __try {
        // make sure the counter values are valid before continuing
        if (pRawValue1 != NULL) {
            if ((pRawValue1->CStatus != PDH_CSTATUS_NEW_DATA) &&
                            (pRawValue1->CStatus != PDH_CSTATUS_VALID_DATA)) {
                dwValueStatus = pRawValue1->CStatus;
                lStatus       = PDH_INVALID_DATA;
            }
        }
        else {
            // this is a required parameter
            dwValueStatus = PDH_CSTATUS_INVALID_DATA;
            lStatus       = PDH_INVALID_ARGUMENT;
        }

        if ((lStatus == ERROR_SUCCESS) && (pRawValue2 != NULL)) {
            if (PdhiCounterNeedLastValue(dwCounterType) == TRUE) {
                // this is an optional parameter, but if present, it must be valid
                if ((pRawValue2->CStatus != PDH_CSTATUS_NEW_DATA) &&
                                (pRawValue2->CStatus != PDH_CSTATUS_VALID_DATA)) {
                    dwValueStatus = pRawValue2->CStatus;
                    lStatus       = PDH_INVALID_DATA;
                }
            }
        }

        if (((dwFormat & PDH_FMT_LONG) != 0) && ((dwFormat & PDH_FMT_LARGE) != 0)) {
            dwValueStatus = PDH_CSTATUS_INVALID_DATA;
            lStatus       = PDH_INVALID_ARGUMENT;
        }
        else if (((dwFormat & PDH_FMT_LONG) != 0) || ((dwFormat & PDH_FMT_LARGE) != 0)) {
            if (dwFormat & PDH_FMT_DOUBLE) {
                dwValueStatus = PDH_CSTATUS_INVALID_DATA;
                lStatus       = PDH_INVALID_ARGUMENT;
            }
        }

        if (lScale > PDH_MAX_SCALE || lScale < PDH_MIN_SCALE) {
            dwValueStatus = PDH_CSTATUS_INVALID_DATA;
            lStatus       = PDH_INVALID_ARGUMENT;
        }
        if (pTimeBase == NULL) {
            dwValueStatus = PDH_CSTATUS_INVALID_DATA;
            lStatus       = PDH_INVALID_ARGUMENT;
        }
        else {
            LONGLONG tmpTimeBase = * pTimeBase;
            * pTimeBase = tmpTimeBase;
        }
    }
    __except (EXCEPTION_EXECUTE_HANDLER) {
        dwValueStatus = PDH_CSTATUS_INVALID_DATA;
        lStatus       = PDH_INVALID_ARGUMENT;
    }
    if (lStatus == ERROR_SUCCESS) {
        // call the counter's calculation function if the raw value is valid
        if (IsSuccessSeverity(pRawValue1->CStatus)) {
            __try {
                dResult = (* pCalcFunc)(pRawValue1, pRawValue2, pTimeBase, & dwValueStatus);
                // format returned value

                if ((dwCounterType & 0xF0000000) == PERF_DISPLAY_PERCENT) {
                    // scale to show percent
                    dResult *= (double) 100.0;
                    // this should probably be controlled by a registry
                    // value as is the case with PERFMON
                    if (! (dwFormat & PDH_FMT_NOCAP100)) {
                        if (dResult > (double) 100.0) dResult = (double) 100.0;
                    }
                }
                if (!(dwFormat & PDH_FMT_NOSCALE)) {
                    //now scale
                    dScale   = pow(10.0, (double)lScale);
                    dResult *= dScale;
                }

                if (dwFormat & PDH_FMT_1000) {
                    //now scale
                    dResult *= (double) 1000.0;
                }
            }
            __except (EXCEPTION_EXECUTE_HANDLER) {
                // something failed
                dResult       = (double) 0.0;
                dwValueStatus = PDH_INVALID_ARGUMENT;
            }
        }
        else {
            dwValueStatus = pRawValue1->CStatus;
        }
        if (!IsSuccessSeverity(dwValueStatus)) {
            // an error occured so pass that on to the caller
            lStatus = dwValueStatus;
        }
    } //end if valid counter data

    // now format
    __try {
        if (dwFormat & PDH_FMT_LONG) {
            pValue->longValue = (LONG) dResult;
        }
        else if (dwFormat & PDH_FMT_LARGE) {
            pValue->largeValue = (LONGLONG) dResult;
        }
        else {
            // double is the default
            pValue->doubleValue = dResult;
        }
        pValue->CStatus = dwValueStatus;
    }
    __except (EXCEPTION_EXECUTE_HANDLER) {
        lStatus = PDH_INVALID_ARGUMENT;
    }
    return lStatus;
}