/**
UINTN subtraction
Performs the requested operation using the input parameters into a value
specified by Result type and stores the converted value into the caller
allocated output buffer specified by Result. The caller must pass in a
Result buffer that is at least as large as the Result type.
If Result is NULL, RETURN_INVALID_PARAMETER is returned.
If the requested operation results in an overflow or an underflow condition,
then Result is set to UINTN_ERROR and RETURN_BUFFER_TOO_SMALL is returned.
@param[in] Minuend A number from which another is to be subtracted.
@param[in] Subtrahend A number to be subtracted from another
@param[out] Result Pointer to the result of subtraction
@retval RETURN_SUCCESS Successful subtraction
@retval RETURN_BUFFER_TOO_SMALL Underflow
@retval RETURN_INVALID_PARAMETER Result is NULL
**/
RETURN_STATUS
EFIAPI
SafeUintnSub (
IN UINTN Minuend,
IN UINTN Subtrahend,
OUT UINTN *Result
)
{
RETURN_STATUS Status;
if (Result == NULL) {
return RETURN_INVALID_PARAMETER;
}
if (sizeof (UINTN) == sizeof (UINT32)) {
if (Minuend >= Subtrahend) {
*Result = (Minuend - Subtrahend);
Status = RETURN_SUCCESS;
} else {
*Result = UINTN_ERROR;
Status = RETURN_BUFFER_TOO_SMALL;
}
return Status;
}
return SafeUint64Sub ((UINT64)Minuend, (UINT64)Subtrahend, (UINT64 *)Result);
}
/**
UINTN subtraction
Performs the requested operation using the input parameters into a value
specified by Result type and stores the converted value into the caller
allocated output buffer specified by Result. The caller must pass in a
Result buffer that is at least as large as the Result type.
If Result is NULL, RETURN_INVALID_PARAMETER is returned.
If the requested operation results in an overflow or an underflow condition,
then Result is set to UINTN_ERROR and RETURN_BUFFER_TOO_SMALL is returned.
@param[in] Minuend A number from which another is to be subtracted.
@param[in] Subtrahend A number to be subtracted from another
@param[out] Result Pointer to the result of subtraction
@retval RETURN_SUCCESS Successful subtraction
@retval RETURN_BUFFER_TOO_SMALL Underflow
@retval RETURN_INVALID_PARAMETER Result is NULL
**/
RETURN_STATUS
EFIAPI
SafeUintnSub (
IN UINTN Minuend,
IN UINTN Subtrahend,
OUT UINTN *Result
)
{
return SafeUint64Sub ((UINT64)Minuend, (UINT64)Subtrahend, (UINT64 *)Result);
}
