Function evlTrunc

src/jrd/SysFunction.cpp:6659–6789

dsc* evlTrunc(thread_db* tdbb, const SysFunction* function, const NestValueArray& args,
	impure_value* impure)
{
	fb_assert(args.getCount() >= 1);

	Request* request = tdbb->getRequest();

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

	SLONG resultScale = 0;
	if (args.getCount() > 1)
	{
		const dsc* scaleDsc = EVL_expr(tdbb, request, args[1]);
		if (request->req_flags & req_null)	// return NULL if scaleDsc is NULL
			return NULL;

		resultScale = MOV_get_long(tdbb, scaleDsc, 0);
		if (!(resultScale >= MIN_SCHAR && resultScale <= MAX_SCHAR))
		{
			status_exception::raise(Arg::Gds(isc_expression_eval_err) <<
										Arg::Gds(isc_sysf_invalid_scale) <<
											Arg::Str(function->name));
		}
		resultScale = -resultScale;
	}

	if (value->isExact())
	{
		SSHORT scale = value->dsc_scale;
		if (value->isInt128())
			impure->vlu_misc.vlu_int128 = MOV_get_int128(tdbb, value, scale);
		else
			impure->vlu_misc.vlu_int64 = MOV_get_int64(tdbb, value, scale);

		if (resultScale < scale)
			resultScale = scale;

		scale -= resultScale;

		if (scale < 0)
		{
			while (scale)
			{
				if (value->isInt128())
					impure->vlu_misc.vlu_int128 = impure->vlu_misc.vlu_int128 / 10;
				else
					impure->vlu_misc.vlu_int64 /= 10;

				++scale;
			}
		}

		if (value->isInt128())
			impure->vlu_desc.makeInt128(resultScale, &impure->vlu_misc.vlu_int128);
		else
			impure->vlu_desc.makeInt64(resultScale, &impure->vlu_misc.vlu_int64);