Enum Command 

#[non_exhaustive]
pub enum Command {
    SetSpeed(Speed),
    SetFunction {
        addr: u32,
        value: u16,
    },
    EmergencyStop,
    QuerySpeed,
    QueryFunction {
        addr: u32,
    },
    AssignController {
        flags: u8,
        controller: NodeId,
    },
    ReleaseController {
        flags: u8,
        controller: NodeId,
    },
    QueryController,
    ControllerChangingNotify {
        flags: u8,
        new_controller: NodeId,
    },
    Reserve,
    Release,
    Noop,
    Unknown(Vec<u8>),
}

A Traction Control Command (throttle → train).

Encode with Command::encode and send as the payload of Message::TractionCommand. A train implementation decodes incoming payloads with Command::decode.

use rolcb::traction::{Command, Speed};
use rolcb::NodeId;

let me = NodeId::new(0x0501_0101_2299);
let bytes = Command::AssignController { flags: 0, controller: me }.encode();
assert_eq!(bytes, [0x20, 0x01, 0x00, 0x05, 0x01, 0x01, 0x01, 0x22, 0x99]);
assert_eq!(Command::decode(&bytes), Command::AssignController { flags: 0, controller: me });

assert_eq!(Command::Noop.encode(), [0x40, 0x03]);
assert_eq!(Command::decode(&[0x7F]), Command::Unknown(vec![0x7F]));

The enum is #[non_exhaustive]: match it with a _ arm.

Variants (Non-exhaustive)

Non-exhaustive enums could have additional variants added in future. Therefore, when matching against variants of non-exhaustive enums, an extra wildcard arm must be added to account for any future variants.

SetSpeed(Speed)

Set speed and direction (0x00). Also clears an emergency stop.

SetFunction

Set a function (0x01). For DCC trains, addresses 0..=28 are F0..F28.

Fields

addr: u32

24-bit function address.

value: u16

New value; for on/off functions 0 = off, 1 = on (see function_value).

EmergencyStop

Emergency stop (0x02): stop immediately, ignoring momentum.

QuerySpeed

Ask for the current speed (0x10); answered by Reply::QuerySpeed.

QueryFunction

Ask for a function value (0x11); answered by Reply::QueryFunction.

Fields

addr: u32

24-bit function address.

AssignController

Become this train’s controller (0x20 0x01). Answered by Reply::AssignController; if another throttle was in control, the train first asks it with Command::ControllerChangingNotify.

Fields

flags: u8

Flags byte (0 for a normal throttle).

controller: NodeId

The controlling throttle’s Node ID.

ReleaseController

Stop being this train’s controller (0x20 0x02).

Fields

flags: u8

Flags byte (normally 0).

controller: NodeId

The Node ID that was assigned.

QueryController

Ask which node controls the train (0x20 0x03).

ControllerChangingNotify

Controller Changing Notify (0x20 0x04 flags NodeID), train → current controller: another node (new_controller) asked to take over. The controller answers with Reply::ControllerChanged (result 0 = accept). This is the one command a throttle receives; Node never auto-rejects it.

Fields

flags: u8

Flags byte (normally 0).

new_controller: NodeId

The node that wants to become the controller.

Reserve

Reserve the train for a multi-step operation (0x40 0x01).

Release

Release a reservation (0x40 0x02).

Noop

Keep-alive, also the answer to a heartbeat request.

Encoded as 0x40 0x03.

Unknown(Vec<u8>)

Anything not recognised (or too short to decode), raw bytes kept.

Implementations

impl Command

pub fn encode(&self) -> Vec<u8>

Serialize to the command payload bytes.

pub fn decode(p: &[u8]) -> Command

Parse command payload bytes. Never fails; unknown or truncated commands become Command::Unknown. The consist LISTENER_FLAG bit in byte 0 is ignored.

pub fn is_controller_changing_notify(payload: &[u8]) -> bool

True if payload is a Controller Changing Notify command (20 04 …), the one Traction Control Command a throttle receives. Cheaper than a full Command::decode.

use rolcb::traction::Command;
assert!(Command::is_controller_changing_notify(&[0x20, 0x04, 0, 5, 1, 1, 1, 0x22, 0x77]));
assert!(!Command::is_controller_changing_notify(&[0x20, 0x01]));

Trait Implementations

impl Clone for Command

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Command

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

Formats the value using the given formatter.

impl Eq for Command

impl Hash for Command

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl PartialEq for Command

fn eq(&self, other: &Self) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for Command