Function xdr_protocol_overhead

src/remote/protocol.cpp:1215–1270

ULONG xdr_protocol_overhead(P_OP op)
{
/**************************************
 *
 *	x d r _ p r o t o c o l _ o v e r h e a d
 *
 **************************************
 *
 * Functional description
 *	Report the overhead size of a particular packet.
 *	NOTE: This is not the same as the actual size to
 *	send the packet - as this figure discounts any data
 *	to be sent with the packet.  It's purpose is to figure
 *	overhead for deciding on a batching window count.
 *
 *	A better version of this routine would use xdr_sizeof - but
 *	it is unknown how portable that Solaris call is to other
 *	OS.
 *
 **************************************/
	ULONG size = 4; // xdr_sizeof (xdr_enum, p->p_operation)

	switch (op)
	{
	case op_fetch_response:
		size += 4				// xdr_sizeof (xdr_long, sqldata->p_sqldata_status)
			+ 4;				// xdr_sizeof (xdr_short, sqldata->p_sqldata_messages)
		break;

	case op_send:
	case op_start_and_send:
	case op_start_send_and_receive:
		size += 4				// xdr_sizeof (xdr_short, data->p_data_request)
			+ 4					// xdr_sizeof (xdr_short, data->p_data_incarnation)
			+ 4					// xdr_sizeof (xdr_short, data->p_data_transaction)
			+ 4					// xdr_sizeof (xdr_short, data->p_data_message_number)
			+ 4;				// xdr_sizeof (xdr_short, data->p_data_messages)
		break;

	case op_response:
	case op_response_piggyback:
		// Note: minimal amounts are used for cstring & status_vector
		size += 4				// xdr_sizeof (xdr_short, response->p_resp_object)
			+ 8					// xdr_sizeof (xdr_quad, response->p_resp_blob_id)
			+ 4					// xdr_sizeof (xdr_cstring, response->p_resp_data)
			+
			3 *
			4;					// xdr_sizeof (xdr_status_vector (xdrs, response->p_resp_status_vector
		break;

	default:
		fb_assert(FALSE);		// Not supported operation
		return 0;
	}
	return size;
}