Function evlPower

src/jrd/SysFunction.cpp:6147–6204

dsc* evlPower(thread_db* tdbb, const SysFunction* function, const NestValueArray& args,
	impure_value* impure)
{
	fb_assert(args.getCount() == 2);

	Request* request = tdbb->getRequest();

	const dsc* value[2];
	value[0] = EVL_expr(tdbb, request, args[0]);
	if (request->req_flags & req_null)	// return NULL if value is NULL
		return NULL;

	value[1] = EVL_expr(tdbb, request, args[1]);
	if (request->req_flags & req_null)	// return NULL if value is NULL
		return NULL;

	if (!areParamsDouble(2, value))
	{
		DecimalStatus decSt = tdbb->getAttachment()->att_dec_status;
		impure->vlu_misc.vlu_dec128 = MOV_get_dec128(tdbb, value[0]);
		Decimal128 v2 = MOV_get_dec128(tdbb, value[1]);

		impure->vlu_misc.vlu_dec128 = impure->vlu_misc.vlu_dec128.pow(decSt, v2);
		impure->vlu_desc.makeDecimal128(&impure->vlu_misc.vlu_dec128);
	}
	else
	{
		impure->vlu_desc.makeDouble(&impure->vlu_misc.vlu_double);

		const double v1 = MOV_get_double(tdbb, value[0]);
		const double v2 = MOV_get_double(tdbb, value[1]);

		if (v1 == 0 && v2 < 0)
		{
			status_exception::raise(Arg::Gds(isc_expression_eval_err) <<
										Arg::Gds(isc_sysf_invalid_zeropowneg) <<
											Arg::Str(function->name));
		}

		if (v1 < 0 &&
			(!value[1]->isExact() ||
			 MOV_get_int64(tdbb, value[1], 0) * SINT64(CVT_power_of_ten(-value[1]->dsc_scale)) !=
				MOV_get_int64(tdbb, value[1], value[1]->dsc_scale)))
		{
			status_exception::raise(Arg::Gds(isc_expression_eval_err) <<
										Arg::Gds(isc_sysf_invalid_negpowfp) <<
											Arg::Str(function->name));
		}

		const double rc = pow(v1, v2);
		if (std::isinf(rc))
			status_exception::raise(Arg::Gds(isc_arith_except) << Arg::Gds(isc_exception_float_overflow));

		impure->vlu_misc.vlu_double = rc;
	}

	return &impure->vlu_desc;
}