www.pudn.com > snmp.rar > oid.c
/*++
Copyright (c) 1992-1997 Microsoft Corporation
Module Name:
oid.c
Abstract:
Contains routines to manipulatee object identifiers.
SnmpUtilOidCpy
SnmpUtilOidAppend
SnmpUtilOidNCmp
SnmpUtilOidCmp
SnmpUtilOidFree
Environment:
User Mode - Win32
Revision History:
--*/
///////////////////////////////////////////////////////////////////////////////
// //
// Include files //
// //
///////////////////////////////////////////////////////////////////////////////
#include
#include
///////////////////////////////////////////////////////////////////////////////
// //
// Public Procedures //
// //
///////////////////////////////////////////////////////////////////////////////
SNMPAPI
SNMP_FUNC_TYPE
SnmpUtilOidCpy(
AsnObjectIdentifier * pOidDst,
AsnObjectIdentifier * pOidSrc
)
/*++
Routine Description:
Copy an object identifier.
Arguments:
pOidDst - pointer to structure to receive OID.
pOidSrc - pointer to OID to copy.
Return Values:
Returns SNMPAPI_NOERROR if successful.
--*/
{
SNMPAPI nResult = SNMPAPI_ERROR;
// validate pointers
if (pOidDst != NULL) {
// initialize
pOidDst->ids = NULL;
pOidDst->idLength = 0;
// check for subids
if ((pOidSrc != NULL) &&
(pOidSrc->ids != NULL) &&
(pOidSrc->idLength != 0)) {
// attempt to allocate the subids
pOidDst->ids = (UINT *)SnmpUtilMemAlloc(
pOidSrc->idLength * sizeof(UINT)
);
// validate pointer
if (pOidDst->ids != NULL) {
// transfer the oid length
pOidDst->idLength = pOidSrc->idLength;
// transfer subids
memcpy(pOidDst->ids,
pOidSrc->ids,
pOidSrc->idLength * sizeof(UINT)
);
nResult = SNMPAPI_NOERROR; // success...
} else {
SNMPDBG((
SNMP_LOG_ERROR,
"SNMP: API: could not allocate oid.\n"
));
SetLastError(SNMP_MEM_ALLOC_ERROR);
}
} else {
SNMPDBG((
SNMP_LOG_WARNING,
"SNMP: API: copying a null oid.\n"
));
nResult = SNMPAPI_NOERROR; // success...
}
} else {
SNMPDBG((
SNMP_LOG_ERROR,
"SNMP: API: null oid pointer during copy.\n"
));
SetLastError(ERROR_INVALID_PARAMETER);
}
return nResult;
}
SNMPAPI
SNMP_FUNC_TYPE
SnmpUtilOidAppend(
AsnObjectIdentifier * pOidDst,
AsnObjectIdentifier * pOidSrc
)
/*++
Routine Description:
Append source OID to destination OID
Arguments:
pOidDst - pointer to structure to receive combined OID.
pOidSrc - pointer to OID to append.
Return Values:
Returns SNMPAPI_NOERROR if successful.
--*/
{
SNMPAPI nResult = SNMPAPI_ERROR;
// validate pointers
if (pOidDst != NULL) {
// check if there are subids
if ((pOidSrc != NULL) &&
(pOidSrc->ids != NULL) &&
(pOidSrc->idLength != 0)) {
// calculate the total number of subidentifiers
UINT nIds = pOidDst->idLength + pOidSrc->idLength;
// validate number of subids
if (nIds <= SNMP_MAX_OID_LEN) {
// attempt to allocate the subidentifiers
UINT * pIds = (UINT *)SnmpUtilMemReAlloc(
pOidDst->ids,
nIds * sizeof(UINT)
);
// validate pointer
if (pIds != NULL) {
// transfer pointer
pOidDst->ids = pIds;
// transfer subids
memcpy(&pOidDst->ids[pOidDst->idLength],
pOidSrc->ids,
pOidSrc->idLength * sizeof(UINT)
);
// transfer oid length
pOidDst->idLength = nIds;
nResult = SNMPAPI_NOERROR; // success...
} else {
SNMPDBG((
SNMP_LOG_ERROR,
"SNMP: API: could not allocate oid.\n"
));
SetLastError(SNMP_MEM_ALLOC_ERROR);
}
} else {
SNMPDBG((
SNMP_LOG_ERROR,
"SNMP: API: combined oid too large.\n"
));
SetLastError(SNMP_BERAPI_OVERFLOW);
}
} else {
SNMPDBG((
SNMP_LOG_WARNING,
"SNMP: API: appending a null oid.\n"
));
nResult = SNMPAPI_NOERROR; // success...
}
} else {
SNMPDBG((
SNMP_LOG_ERROR,
"SNMP: API: null oid pointer during copy.\n"
));
SetLastError(ERROR_INVALID_PARAMETER);
}
return nResult;
}
SNMPAPI
SNMP_FUNC_TYPE
SnmpUtilOidNCmp(
AsnObjectIdentifier * pOid1,
AsnObjectIdentifier * pOid2,
UINT nSubIds
)
/*++
Routine Description:
Compares two OIDs up to a certain subidentifier.
Arguments:
pOid1 - pointer to first OID.
pOid2 - pointer to second OID.
nSubIds - maximum subidentifiers to compare.
Return Values:
< 0 first parameter is 'less than' second.
0 first parameter is 'equal to' second.
> 0 first parameter is 'greater than' second.
--*/
{
UINT i = 0;
// INT nResult = 0;
// validate pointers
if ((pOid1 != NULL) &&
(pOid2 != NULL)) {
// calculate maximum number of subidentifiers to compare
UINT nMaxIds = min(nSubIds, min(pOid1->idLength, pOid2->idLength));
/*
// loop through the subidentifiers
while((nResult == 0) && (i < nMaxIds)) {
// compare each subidentifier
nResult = pOid1->ids[i] - pOid2->ids[i++];
}
*/
while(i < nMaxIds)
{
if (pOid1->ids[i] != pOid2->ids[i])
break;
i++;
}
// comparision length less then either OID lengths; components equals
if (i == nSubIds)
return 0;
// difference encountered before either OID endings and before the
// requested comparision length
if (i < nMaxIds)
return (pOid1->ids[i] < pOid2->ids[i])? -1 : 1;
// one OID is shorter than the requested comparision length
return pOid1->idLength - pOid2->idLength;
/*
// check for second being subset
if ((nResult == 0) && (i < nSubIds)) {
// determine order by length of oid
nResult = pOid1->idLength - pOid2->idLength;
}
*/
}
// return nResult;
return 0;
}
SNMPAPI
SNMP_FUNC_TYPE
SnmpUtilOidCmp(
AsnObjectIdentifier * pOid1,
AsnObjectIdentifier * pOid2
)
/*++
Routine Description:
Compares two OIDs.
Arguments:
pOid1 - pointer to first OID.
pOid2 - pointer to second OID.
Return Values:
< 0 first parameter is 'less than' second.
0 first parameter is 'equal to' second.
> 0 first parameter is 'greater than' second.
--*/
{
// forward request to the function above
return SnmpUtilOidNCmp(pOid1,pOid2,max(pOid1->idLength,pOid2->idLength));
}
VOID
SNMP_FUNC_TYPE
SnmpUtilOidFree(
AsnObjectIdentifier * pOid
)
/*++
Routine Description:
Releases memory associated with OID.
Arguments:
pOid - pointer to OID to free.
Return Values:
None.
--*/
{
// validate
if (pOid != NULL) {
// release subids memory
SnmpUtilMemFree(pOid->ids);
// re-initialize
pOid->idLength = 0;
pOid->ids = NULL;
}
}