Struct Header

pub struct Header {
    pub timestamp: DateTime<Utc>,
    pub channel: u8,
    pub destination_address: u16,
    pub source_address: u16,
    pub protocol_version: u8,
}

All VBus data types consist of a Header element.

Just like the fact that the first 6 bytes of each VBus live byte stream are the same (SYNC to protocol version), the Header struct is the common type for all concrete VBus data types.

In addition to the information stored within the first 6 bytes of the VBus header (destination and source addresses as well as the protocol version), the Header type also stores the VBus channel associated with this data as well as the point in time the data was received.

The “identity” of Header values

The fields in the Header struct can be separated into two categories:

1. Fields that are used to identify the Header and (for concrete VBus data types) its payload:
   • channel
   • source_address
   • destination_address
   • protocol_version
2. Fields that are not used to identify the Header:
   • timestamp

Two Header values with different timestamp fields are considered identical, if all of their other fields match.

This is also respected by the id_hash and id_string functions. They return the same result for VBus data values that are considered “identical”, allowing some fields to differ.

Fields

timestamp: DateTime<Utc>

The timestamp when this Header was received.

channel: u8

The channel number on which this Header was received.

destination_address: u16

The destination address of this Header.

source_address: u16

The source address of this Header.

protocol_version: u8

The VBus protocol version of this Header.

Implementations

impl Header

pub fn id_string(&self) -> String

Creates the common identification string prefix for this Header.

The string contains all fields that count towards the “identity” of the Header:

• channel
• destination_address
• source_address
• protocol_version

Examples

use resol_vbus::{Header};
use resol_vbus::utils::utc_timestamp;

let header = Header {
    timestamp: utc_timestamp(1485688933),
    channel: 0x11,
    destination_address: 0x1213,
    source_address: 0x1415,
    protocol_version: 0x16,
};

assert_eq!("11_1213_1415_16", header.id_string());

Trait Implementations

impl AsRef<Header> for Data

fn as_ref(&self) -> &Header

Converts this type into a shared reference of the (usually inferred) input type.

impl AsRef<Header> for Datagram

fn as_ref(&self) -> &Header

Converts this type into a shared reference of the (usually inferred) input type.

impl AsRef<Header> for Packet

fn as_ref(&self) -> &Header

Converts this type into a shared reference of the (usually inferred) input type.

impl AsRef<Header> for Telegram

fn as_ref(&self) -> &Header

Converts this type into a shared reference of the (usually inferred) input type.

impl Clone for Header

fn clone(&self) -> Header

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Header

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl Default for Header

fn default() -> Header

Returns the “default value” for a type.

impl IdHash for Header

fn id_hash<H>(&self, h: &mut H)

where H: Hasher,

Returns an identification hash for this Header.

The hash contains all fields that count towards the “identity” of the Header:

• channel
• destination_address
• source_address
• protocol_version

Examples

use resol_vbus::{Header, id_hash};
use resol_vbus::utils::utc_timestamp;

let header = Header {
    timestamp: utc_timestamp(1485688933),
    channel: 0x11,
    destination_address: 0x1213,
    source_address: 0x1415,
    protocol_version: 0x16,
};

assert_eq!(8369676560183260683, id_hash(&header));