Function evlPosition

src/jrd/SysFunction.cpp:6021–6144

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

	Request* request = tdbb->getRequest();

	const dsc* value1 = EVL_expr(tdbb, request, args[0]);
	if (request->req_flags & req_null)	// return NULL if value1 is NULL
		return NULL;

	const dsc* value2 = EVL_expr(tdbb, request, args[1]);
	if (request->req_flags & req_null)	// return NULL if value2 is NULL
		return NULL;

	SLONG start = 1;

	if (args.getCount() >= 3)
	{
		const dsc* value3 = EVL_expr(tdbb, request, args[2]);
		if (request->req_flags & req_null)	// return NULL if value3 is NULL
			return NULL;

		start = MOV_get_long(tdbb, value3, 0);
		if (start <= 0)
		{
			status_exception::raise(Arg::Gds(isc_expression_eval_err) <<
										Arg::Gds(isc_sysf_argnmustbe_positive) <<
											Arg::Num(3) <<
											Arg::Str(function->name));
		}
	}

	// make descriptor for return value
	impure->vlu_desc.makeLong(0, &impure->vlu_misc.vlu_long);

	// we'll use the collation from the second string
	const USHORT ttype = value2->getTextType();
	TextType* tt = INTL_texttype_lookup(tdbb, ttype);
	CharSet* cs = tt->getCharSet();
	const UCHAR canonicalWidth = tt->getCanonicalWidth();

	MoveBuffer value1Buffer;
	UCHAR* value1Address;
	ULONG value1Length;

	if (value1->isBlob())
	{
		// value1 is a blob
		blb* blob = blb::open(tdbb, tdbb->getRequest()->req_transaction,
			reinterpret_cast<bid*>(value1->dsc_address));

		value1Address = value1Buffer.getBuffer(blob->blb_length);
		value1Length = blob->BLB_get_data(tdbb, value1Address, blob->blb_length, true);
	}
	else
		value1Length = MOV_make_string2(tdbb, value1, ttype, &value1Address, value1Buffer);