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
//! CAN Identifiers.
/// Standard 11-bit CAN Identifier (`0..=0x7FF`).
#[derive(Debug, Copy, Clone, Eq, PartialEq, PartialOrd, Ord, Hash)]
pub struct StandardId(u16);
impl StandardId {
/// CAN ID `0`, the highest priority.
pub const ZERO: Self = Self(0);
/// CAN ID `0x7FF`, the lowest priority.
pub const MAX: Self = Self(0x7FF);
/// Tries to create a `StandardId` from a raw 16-bit integer.
///
/// This will return `None` if `raw` is out of range of an 11-bit integer (`> 0x7FF`).
#[inline]
pub const fn new(raw: u16) -> Option<Self> {
if raw <= 0x7FF {
Some(Self(raw))
} else {
None
}
}
/// Creates a new `StandardId` without checking if it is inside the valid range.
///
/// # Safety
/// Using this method can create an invalid ID and is thus marked as unsafe.
#[inline]
pub const unsafe fn new_unchecked(raw: u16) -> Self {
Self(raw)
}
/// Returns this CAN Identifier as a raw 16-bit integer.
#[inline]
pub fn as_raw(&self) -> u16 {
self.0
}
}
/// Extended 29-bit CAN Identifier (`0..=1FFF_FFFF`).
#[derive(Debug, Copy, Clone, Eq, PartialEq, PartialOrd, Ord, Hash)]
pub struct ExtendedId(u32);
impl ExtendedId {
/// CAN ID `0`, the highest priority.
pub const ZERO: Self = Self(0);
/// CAN ID `0x1FFFFFFF`, the lowest priority.
pub const MAX: Self = Self(0x1FFF_FFFF);
/// Tries to create a `ExtendedId` from a raw 32-bit integer.
///
/// This will return `None` if `raw` is out of range of an 29-bit integer (`> 0x1FFF_FFFF`).
#[inline]
pub const fn new(raw: u32) -> Option<Self> {
if raw <= 0x1FFF_FFFF {
Some(Self(raw))
} else {
None
}
}
/// Creates a new `ExtendedId` without checking if it is inside the valid range.
///
/// # Safety
/// Using this method can create an invalid ID and is thus marked as unsafe.
#[inline]
pub const unsafe fn new_unchecked(raw: u32) -> Self {
Self(raw)
}
/// Returns this CAN Identifier as a raw 32-bit integer.
#[inline]
pub fn as_raw(&self) -> u32 {
self.0
}
/// Returns the Base ID part of this extended identifier.
pub fn standard_id(&self) -> StandardId {
// ID-28 to ID-18
StandardId((self.0 >> 18) as u16)
}
}
/// A CAN Identifier (standard or extended).
#[derive(Debug, Copy, Clone, Eq, PartialEq, Hash)]
pub enum Id {
/// Standard 11-bit Identifier (`0..=0x7FF`).
Standard(StandardId),
/// Extended 29-bit Identifier (`0..=0x1FFF_FFFF`).
Extended(ExtendedId),
}
/// Implement `Ord` according to the CAN arbitration rules
///
/// When performing arbitration, frames are looked at bit for bit starting
/// from the beginning. A bit with the value 0 is dominant and a bit with
/// value of 1 is recessive.
///
/// When two devices are sending frames at the same time, as soon as the first
/// bit is found which differs, the frame with the corresponding dominant
/// 0 bit will win and get to send the rest of the frame.
///
/// This implementation of `Ord` for `Id` will take this into consideration
/// and when comparing two different instances of `Id` the "smallest" will
/// always be the ID which would form the most dominant frame, all other
/// things being equal.
impl Ord for Id {
fn cmp(&self, other: &Self) -> core::cmp::Ordering {
let split_id = |id: &Id| {
let (standard_id_part, ide_bit, extended_id_part) = match id {
Id::Standard(StandardId(x)) => (*x, 0, 0),
Id::Extended(x) => (
x.standard_id().0,
1,
x.0 & ((1 << 18) - 1), // Bit ID-17 to ID-0
),
};
(standard_id_part, ide_bit, extended_id_part)
};
split_id(self).cmp(&split_id(other))
}
}
impl PartialOrd for Id {
fn partial_cmp(&self, other: &Id) -> Option<core::cmp::Ordering> {
Some(self.cmp(other))
}
}
impl From<StandardId> for Id {
#[inline]
fn from(id: StandardId) -> Self {
Id::Standard(id)
}
}
impl From<ExtendedId> for Id {
#[inline]
fn from(id: ExtendedId) -> Self {
Id::Extended(id)
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn standard_id_new() {
assert_eq!(
StandardId::new(StandardId::MAX.as_raw()),
Some(StandardId::MAX)
);
}
#[test]
fn standard_id_new_out_of_range() {
assert_eq!(StandardId::new(StandardId::MAX.as_raw() + 1), None);
}
#[test]
fn standard_id_new_unchecked_out_of_range() {
let id = StandardId::MAX.as_raw() + 1;
assert_eq!(unsafe { StandardId::new_unchecked(id) }, StandardId(id));
}
#[test]
fn extended_id_new() {
assert_eq!(
ExtendedId::new(ExtendedId::MAX.as_raw()),
Some(ExtendedId::MAX)
);
}
#[test]
fn extended_id_new_out_of_range() {
assert_eq!(ExtendedId::new(ExtendedId::MAX.as_raw() + 1), None);
}
#[test]
fn extended_id_new_unchecked_out_of_range() {
let id = ExtendedId::MAX.as_raw() + 1;
assert_eq!(unsafe { ExtendedId::new_unchecked(id) }, ExtendedId(id));
}
#[test]
fn get_standard_id_from_extended_id() {
assert_eq!(
Some(ExtendedId::MAX.standard_id()),
StandardId::new((ExtendedId::MAX.0 >> 18) as u16)
);
}
#[test]
fn cmp_id() {
assert!(StandardId::ZERO < StandardId::MAX);
assert!(ExtendedId::ZERO < ExtendedId::MAX);
assert!(Id::Standard(StandardId::ZERO) < Id::Extended(ExtendedId::ZERO));
assert!(Id::Extended(ExtendedId::ZERO) < Id::Extended(ExtendedId::MAX));
assert!(Id::Extended(ExtendedId((1 << 11) - 1)) < Id::Standard(StandardId(1)));
assert!(Id::Standard(StandardId(1)) < Id::Extended(ExtendedId::MAX));
}
}