bloop_server_framework/
nfc_uid.rs

1use hex::{FromHex, FromHexError, decode_to_slice};
2use thiserror::Error;
3
4#[derive(Debug, Error)]
5pub enum Error {
6    #[error("Invalid UID length, must be 4, 7 or 10")]
7    InvalidLength,
8}
9
10/// Represents an NFC UID of standard lengths.
11///
12/// NFC UIDs come in three typical sizes:
13///
14/// - `Single`: 4 bytes
15/// - `Double`: 7 bytes
16/// - `Triple`: 10 bytes
17///
18/// This enum encapsulates these variants and ensures correct sizing during
19/// construction via `TryFrom<&[u8]>` or hex parsing (`FromHex`).
20///
21/// Use [`as_bytes()`] to get a byte slice of the underlying UID.
22///
23/// # Examples
24///
25/// ```
26/// use bloop_server_framework::nfc_uid::NfcUid;
27///
28/// let uid = NfcUid::try_from(&[0x01, 0x02, 0x03, 0x04][..]).unwrap();
29/// assert_eq!(uid.as_bytes(), &[0x01, 0x02, 0x03, 0x04]);
30/// ```
31#[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)]
32pub enum NfcUid {
33    Single([u8; 4]),
34    Double([u8; 7]),
35    Triple([u8; 10]),
36}
37
38impl Default for NfcUid {
39    fn default() -> Self {
40        Self::Single(Default::default())
41    }
42}
43
44impl TryFrom<&[u8]> for NfcUid {
45    type Error = Error;
46
47    fn try_from(value: &[u8]) -> Result<Self, Self::Error> {
48        match value.len() {
49            4 => Ok(NfcUid::Single(value.try_into().unwrap())),
50            7 => Ok(NfcUid::Double(value.try_into().unwrap())),
51            10 => Ok(NfcUid::Triple(value.try_into().unwrap())),
52            _ => Err(Error::InvalidLength),
53        }
54    }
55}
56
57impl FromHex for NfcUid {
58    type Error = FromHexError;
59
60    fn from_hex<T: AsRef<[u8]>>(hex: T) -> Result<Self, Self::Error> {
61        let hex_bytes = hex.as_ref();
62        let mut decoded = vec![0u8; hex_bytes.len() / 2];
63        decode_to_slice(hex, &mut decoded)?;
64
65        NfcUid::try_from(decoded.as_slice()).map_err(|_| FromHexError::InvalidStringLength)
66    }
67}
68
69impl NfcUid {
70    pub fn as_bytes(&self) -> &[u8] {
71        match self {
72            NfcUid::Single(data) => data,
73            NfcUid::Double(data) => data,
74            NfcUid::Triple(data) => data,
75        }
76    }
77}
78
79#[cfg(test)]
80mod tests {
81    use super::*;
82    use hex::FromHex;
83
84    #[test]
85    fn from_valid_bytes() {
86        let bytes4 = [0x01, 0x02, 0x03, 0x04];
87        let bytes7 = [0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07];
88        let bytes10 = [0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0A];
89
90        let uid4 = NfcUid::try_from(&bytes4[..]).unwrap();
91        let uid7 = NfcUid::try_from(&bytes7[..]).unwrap();
92        let uid10 = NfcUid::try_from(&bytes10[..]).unwrap();
93
94        assert_eq!(uid4.as_bytes(), &bytes4);
95        assert_eq!(uid7.as_bytes(), &bytes7);
96        assert_eq!(uid10.as_bytes(), &bytes10);
97    }
98
99    #[test]
100    fn from_invalid_bytes_length() {
101        let bytes = [0x01, 0x02];
102        let err = NfcUid::try_from(&bytes[..]).unwrap_err();
103        assert!(matches!(err, Error::InvalidLength));
104
105        let bytes = [0u8; 5];
106        let err = NfcUid::try_from(&bytes[..]).unwrap_err();
107        assert!(matches!(err, Error::InvalidLength));
108    }
109
110    #[test]
111    fn from_valid_hex() {
112        let hex4 = "01020304";
113        let hex7 = "01020304050607";
114        let hex10 = "0102030405060708090a";
115
116        let uid4 = NfcUid::from_hex(hex4).unwrap();
117        let uid7 = NfcUid::from_hex(hex7).unwrap();
118        let uid10 = NfcUid::from_hex(hex10).unwrap();
119
120        assert_eq!(uid4.as_bytes(), &[0x01, 0x02, 0x03, 0x04]);
121        assert_eq!(uid7.as_bytes(), &[0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07]);
122        assert_eq!(
123            uid10.as_bytes(),
124            &[0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a]
125        );
126    }
127
128    #[test]
129    fn from_invalid_hex_format() {
130        let invalid_hex = "xyz"; // Invalid hex
131        assert!(NfcUid::from_hex(invalid_hex).is_err());
132
133        let invalid_length = "010203"; // 3 bytes → invalid UID length
134        let result = NfcUid::from_hex(invalid_length);
135        assert!(matches!(result, Err(FromHexError::InvalidStringLength)));
136    }
137}
bloop_server_framework/nfc_uid.rs

bloop_server_framework/
nfc_uid.rs
