1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255
#[cfg(test)]
mod tests;
use core::cmp::Ordering;
use core::ops::{Deref, DerefMut};
use crate::{Id, IdReg};
/// A CAN data or remote frame.
#[derive(Clone, Debug, Eq)]
#[cfg_attr(feature = "unstable-defmt", derive(defmt::Format))]
pub struct Frame {
pub(crate) id: IdReg,
pub(crate) data: Data,
}
impl Frame {
/// Creates a new data frame.
pub fn new_data(id: impl Into<Id>, data: impl Into<Data>) -> Self {
let id = match id.into() {
Id::Standard(id) => IdReg::new_standard(id),
Id::Extended(id) => IdReg::new_extended(id),
};
Self {
id,
data: data.into(),
}
}
/// Creates a new remote frame with configurable data length code (DLC).
///
/// # Panics
///
/// This function will panic if `dlc` is not inside the valid range `0..=8`.
pub fn new_remote(id: impl Into<Id>, dlc: u8) -> Self {
assert!(dlc <= 8);
let mut frame = Self::new_data(id, []);
// Just extend the data length, even with no data present. The API does not hand out this
// `Data` object.
frame.data.len = dlc;
frame.id = frame.id.with_rtr(true);
frame
}
/// Returns true if this frame is an extended frame.
#[inline]
pub fn is_extended(&self) -> bool {
self.id.is_extended()
}
/// Returns true if this frame is a standard frame.
#[inline]
pub fn is_standard(&self) -> bool {
self.id.is_standard()
}
/// Returns true if this frame is a remote frame.
#[inline]
pub fn is_remote_frame(&self) -> bool {
self.id.rtr()
}
/// Returns true if this frame is a data frame.
#[inline]
pub fn is_data_frame(&self) -> bool {
!self.is_remote_frame()
}
/// Returns the frame identifier.
#[inline]
pub fn id(&self) -> Id {
self.id.to_id()
}
/// Returns the priority of this frame.
#[inline]
pub fn priority(&self) -> FramePriority {
FramePriority(self.id)
}
/// Returns the data length code (DLC) which is in the range 0..8.
///
/// For data frames the DLC value always matches the length of the data.
/// Remote frames do not carry any data, yet the DLC can be greater than 0.
#[inline]
pub fn dlc(&self) -> u8 {
self.data.len() as u8
}
/// Returns the frame data (0..8 bytes in length) if this is a data frame.
///
/// If this is a remote frame, returns `None`.
pub fn data(&self) -> Option<&Data> {
if self.is_data_frame() {
Some(&self.data)
} else {
None
}
}
}
impl PartialEq for Frame {
fn eq(&self, other: &Self) -> bool {
match (self.data(), other.data()) {
(None, None) => self.id.eq(&other.id),
(Some(a), Some(b)) => self.id.eq(&other.id) && a.eq(b),
(None, Some(_)) | (Some(_), None) => false,
}
}
}
/// Priority of a CAN frame.
///
/// Returned by [`Frame::priority`].
///
/// The priority of a frame is determined by the bits that are part of the *arbitration field*.
/// These consist of the frame identifier bits (including the *IDE* bit, which is 0 for extended
/// frames and 1 for standard frames), as well as the *RTR* bit, which determines whether a frame
/// is a data or remote frame. Lower values of the *arbitration field* have higher priority.
///
/// This struct wraps the *arbitration field* and implements `PartialOrd` and `Ord` accordingly,
/// ordering higher priorities greater than lower ones.
#[derive(Debug, Copy, Clone)]
pub struct FramePriority(IdReg);
/// Ordering is based on the Identifier and frame type (data vs. remote) and can be used to sort
/// frames by priority.
impl Ord for FramePriority {
fn cmp(&self, other: &Self) -> Ordering {
self.0.cmp(&other.0)
}
}
impl PartialOrd for FramePriority {
fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
Some(self.cmp(other))
}
}
impl PartialEq for FramePriority {
fn eq(&self, other: &Self) -> bool {
self.cmp(other) == Ordering::Equal
}
}
impl Eq for FramePriority {}
/// Payload of a CAN data frame.
///
/// Contains 0 to 8 Bytes of data.
///
/// `Data` implements `From<[u8; N]>` for all `N` up to 8, which provides a convenient lossless
/// conversion from fixed-length arrays.
#[derive(Debug, Copy, Clone)]
pub struct Data {
pub(crate) len: u8,
pub(crate) bytes: [u8; 8],
}
impl Data {
/// Creates a data payload from a raw byte slice.
///
/// Returns `None` if `data` contains more than 8 Bytes (which is the maximum).
///
/// `Data` can also be constructed from fixed-length arrays up to length 8 via `From`/`Into`.
pub fn new(data: &[u8]) -> Option<Self> {
if data.len() > 8 {
return None;
}
let mut bytes = [0; 8];
bytes[..data.len()].copy_from_slice(data);
Some(Self {
len: data.len() as u8,
bytes,
})
}
/// Creates an empty data payload containing 0 bytes.
#[inline]
pub const fn empty() -> Self {
Self {
len: 0,
bytes: [0; 8],
}
}
}
impl Deref for Data {
type Target = [u8];
#[inline]
fn deref(&self) -> &[u8] {
&self.bytes[..usize::from(self.len)]
}
}
impl DerefMut for Data {
#[inline]
fn deref_mut(&mut self) -> &mut [u8] {
&mut self.bytes[..usize::from(self.len)]
}
}
impl AsRef<[u8]> for Data {
#[inline]
fn as_ref(&self) -> &[u8] {
self.deref()
}
}
impl AsMut<[u8]> for Data {
#[inline]
fn as_mut(&mut self) -> &mut [u8] {
self.deref_mut()
}
}
impl PartialEq for Data {
fn eq(&self, other: &Self) -> bool {
self.as_ref() == other.as_ref()
}
}
impl Eq for Data {}
#[cfg(feature = "unstable-defmt")]
impl defmt::Format for Data {
fn format(&self, fmt: defmt::Formatter<'_>) {
self.as_ref().format(fmt)
}
}
macro_rules! data_from_array {
( $($len:literal),+ ) => {
$(
impl From<[u8; $len]> for Data {
#[inline]
fn from(arr: [u8; $len]) -> Self {
let mut bytes = [0; 8];
bytes[..$len].copy_from_slice(&arr);
Self {
len: $len,
bytes,
}
}
}
)+
};
}
data_from_array!(0, 1, 2, 3, 4, 5, 6, 7, 8);