der/asn1/
oid.rs

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1//! ASN.1 `OBJECT IDENTIFIER`
2
3use crate::{
4    asn1::AnyRef, ord::OrdIsValueOrd, DecodeValue, EncodeValue, Error, FixedTag, Header, Length,
5    Reader, Result, Tag, Tagged, Writer,
6};
7use const_oid::ObjectIdentifier;
8
9impl<'a> DecodeValue<'a> for ObjectIdentifier {
10    fn decode_value<R: Reader<'a>>(reader: &mut R, header: Header) -> Result<Self> {
11        let mut buf = [0u8; ObjectIdentifier::MAX_SIZE];
12        let slice = buf
13            .get_mut(..header.length.try_into()?)
14            .ok_or_else(|| Self::TAG.length_error())?;
15
16        let actual_len = reader.read_into(slice)?.len();
17        debug_assert_eq!(actual_len, header.length.try_into()?);
18        Ok(Self::from_bytes(slice)?)
19    }
20}
21
22impl EncodeValue for ObjectIdentifier {
23    fn value_len(&self) -> Result<Length> {
24        Length::try_from(self.as_bytes().len())
25    }
26
27    fn encode_value(&self, writer: &mut dyn Writer) -> Result<()> {
28        writer.write(self.as_bytes())
29    }
30}
31
32impl FixedTag for ObjectIdentifier {
33    const TAG: Tag = Tag::ObjectIdentifier;
34}
35
36impl OrdIsValueOrd for ObjectIdentifier {}
37
38impl<'a> From<&'a ObjectIdentifier> for AnyRef<'a> {
39    fn from(oid: &'a ObjectIdentifier) -> AnyRef<'a> {
40        // Note: ensuring an infallible conversion is possible relies on the
41        // invariant that `const_oid::MAX_LEN <= Length::max()`.
42        //
43        // The `length()` test below ensures this is the case.
44        let value = oid
45            .as_bytes()
46            .try_into()
47            .expect("OID length invariant violated");
48
49        AnyRef::from_tag_and_value(Tag::ObjectIdentifier, value)
50    }
51}
52
53impl TryFrom<AnyRef<'_>> for ObjectIdentifier {
54    type Error = Error;
55
56    fn try_from(any: AnyRef<'_>) -> Result<ObjectIdentifier> {
57        any.tag().assert_eq(Tag::ObjectIdentifier)?;
58        Ok(ObjectIdentifier::from_bytes(any.value())?)
59    }
60}
61
62#[cfg(test)]
63mod tests {
64    use super::ObjectIdentifier;
65    use crate::{Decode, Encode, Length};
66
67    const EXAMPLE_OID: ObjectIdentifier = ObjectIdentifier::new_unwrap("1.2.840.113549");
68    const EXAMPLE_OID_BYTES: &[u8; 8] = &[0x06, 0x06, 0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d];
69
70    #[test]
71    fn decode() {
72        let oid = ObjectIdentifier::from_der(EXAMPLE_OID_BYTES).unwrap();
73        assert_eq!(EXAMPLE_OID, oid);
74    }
75
76    #[test]
77    fn encode() {
78        let mut buffer = [0u8; 8];
79        assert_eq!(
80            EXAMPLE_OID_BYTES,
81            EXAMPLE_OID.encode_to_slice(&mut buffer).unwrap()
82        );
83    }
84
85    #[test]
86    fn length() {
87        // Ensure an infallible `From` conversion to `Any` will never panic
88        assert!(ObjectIdentifier::MAX_SIZE <= Length::MAX.try_into().unwrap());
89    }
90}
der/asn1/oid.rs

der/asn1/
oid.rs
