Skip to main content

osdp/reply/
rmac_i.rs

1//! `osdp_RMAC_I` (`0x78`) — initial R-MAC.
2//!
3//! # Spec: §7.17, Annex D.4
4
5use crate::error::Error;
6use crate::payload_util::require_exact_len;
7use alloc::vec::Vec;
8
9/// `osdp_RMAC_I` body.
10#[derive(Debug, Clone, Copy, PartialEq, Eq)]
11pub struct RMacI {
12    /// Initial R-MAC seed (16 bytes).
13    pub r_mac_i: [u8; 16],
14}
15
16impl RMacI {
17    /// Encode.
18    pub fn encode(&self) -> Result<Vec<u8>, Error> {
19        Ok(self.r_mac_i.to_vec())
20    }
21
22    /// Decode.
23    pub fn decode(data: &[u8]) -> Result<Self, Error> {
24        require_exact_len(data, 16, 0x78)?;
25        let mut r_mac_i = [0u8; 16];
26        r_mac_i.copy_from_slice(data);
27        Ok(Self { r_mac_i })
28    }
29}
30
31#[cfg(test)]
32mod tests {
33    use super::*;
34
35    #[test]
36    fn roundtrip() {
37        let body = RMacI {
38            r_mac_i: [0x77; 16],
39        };
40        let bytes = body.encode().unwrap();
41        assert_eq!(bytes.len(), 16);
42        assert_eq!(RMacI::decode(&bytes).unwrap(), body);
43    }
44
45    #[test]
46    fn decode_rejects_wrong_length() {
47        assert!(matches!(
48            RMacI::decode(&[0; 15]),
49            Err(Error::PayloadLength { code: 0x78, .. })
50        ));
51    }
52}