pamoja_can/
id.rs

1//! The CAN identifier: a standard 11-bit or extended 29-bit arbitration ID.
2
3/// A CAN arbitration identifier.
4///
5/// CAN comes in two identifier widths: the original standard 11-bit form and the extended
6/// 29-bit form that higher-layer protocols such as J1939 use to pack a priority, a
7/// parameter group, and addresses into the ID itself. This type holds either, always
8/// masked to its width.
9///
10/// # Examples
11///
12/// ```
13/// use pamoja_can::CanId;
14///
15/// let std = CanId::standard(0x123);
16/// assert!(!std.is_extended());
17/// assert_eq!(std.raw(), 0x123);
18///
19/// // Values wider than the identifier are masked to fit.
20/// assert_eq!(CanId::standard(0xFFFF).raw(), 0x7FF);
21/// ```
22#[derive(Clone, Copy, Debug, PartialEq, Eq)]
23pub struct CanId {
24    bits: u32,
25    extended: bool,
26}
27
28impl CanId {
29    /// The mask of a standard 11-bit identifier.
30    pub const STANDARD_MASK: u32 = 0x7FF;
31
32    /// The mask of an extended 29-bit identifier.
33    pub const EXTENDED_MASK: u32 = 0x1FFF_FFFF;
34
35    /// Creates a standard 11-bit identifier, masking the value to fit.
36    ///
37    /// # Arguments
38    ///
39    /// * `raw` - the identifier value; bits above the low 11 are dropped.
40    ///
41    /// # Returns
42    ///
43    /// The identifier.
44    pub fn standard(raw: u16) -> CanId {
45        CanId {
46            bits: u32::from(raw) & Self::STANDARD_MASK,
47            extended: false,
48        }
49    }
50
51    /// Creates an extended 29-bit identifier, masking the value to fit.
52    ///
53    /// # Arguments
54    ///
55    /// * `raw` - the identifier value; bits above the low 29 are dropped.
56    ///
57    /// # Returns
58    ///
59    /// The identifier.
60    pub fn extended(raw: u32) -> CanId {
61        CanId {
62            bits: raw & Self::EXTENDED_MASK,
63            extended: true,
64        }
65    }
66
67    /// Returns the identifier value.
68    ///
69    /// # Returns
70    ///
71    /// The raw bits, already masked to the identifier's width.
72    pub fn raw(&self) -> u32 {
73        self.bits
74    }
75
76    /// Reports whether this is an extended 29-bit identifier.
77    ///
78    /// # Returns
79    ///
80    /// `true` for an extended identifier, `false` for a standard one.
81    pub fn is_extended(&self) -> bool {
82        self.extended
83    }
84}
pamoja_can/id.rs

pamoja_can/
id.rs
