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
9#[cfg(feature = "alloc")]
10use super::Any;
11
12impl<'a> DecodeValue<'a> for ObjectIdentifier {
13    fn decode_value<R: Reader<'a>>(reader: &mut R, header: Header) -> Result<Self> {
14        let mut buf = [0u8; ObjectIdentifier::MAX_SIZE];
15        let slice = buf
16            .get_mut(..header.length.try_into()?)
17            .ok_or_else(|| Self::TAG.length_error())?;
18
19        let actual_len = reader.read_into(slice)?.len();
20        debug_assert_eq!(actual_len, header.length.try_into()?);
21        Ok(Self::from_bytes(slice)?)
22    }
23}
24
25impl EncodeValue for ObjectIdentifier {
26    fn value_len(&self) -> Result<Length> {
27        Length::try_from(self.as_bytes().len())
28    }
29
30    fn encode_value(&self, writer: &mut impl Writer) -> Result<()> {
31        writer.write(self.as_bytes())
32    }
33}
34
35impl FixedTag for ObjectIdentifier {
36    const TAG: Tag = Tag::ObjectIdentifier;
37}
38
39impl OrdIsValueOrd for ObjectIdentifier {}
40
41impl<'a> From<&'a ObjectIdentifier> for AnyRef<'a> {
42    fn from(oid: &'a ObjectIdentifier) -> AnyRef<'a> {
43        // Note: ensuring an infallible conversion is possible relies on the
44        // invariant that `const_oid::MAX_LEN <= Length::max()`.
45        //
46        // The `length()` test below ensures this is the case.
47        let value = oid
48            .as_bytes()
49            .try_into()
50            .expect("OID length invariant violated");
51
52        AnyRef::from_tag_and_value(Tag::ObjectIdentifier, value)
53    }
54}
55
56#[cfg(feature = "alloc")]
57impl From<ObjectIdentifier> for Any {
58    fn from(oid: ObjectIdentifier) -> Any {
59        AnyRef::from(&oid).into()
60    }
61}
62
63impl TryFrom<AnyRef<'_>> for ObjectIdentifier {
64    type Error = Error;
65
66    fn try_from(any: AnyRef<'_>) -> Result<ObjectIdentifier> {
67        any.tag().assert_eq(Tag::ObjectIdentifier)?;
68        Ok(ObjectIdentifier::from_bytes(any.value())?)
69    }
70}
71
72#[cfg(test)]
73mod tests {
74    use super::ObjectIdentifier;
75    use crate::{Decode, Encode, Length};
76
77    const EXAMPLE_OID: ObjectIdentifier = ObjectIdentifier::new_unwrap("1.2.840.113549");
78    const EXAMPLE_OID_BYTES: &[u8; 8] = &[0x06, 0x06, 0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d];
79
80    #[test]
81    fn decode() {
82        let oid = ObjectIdentifier::from_der(EXAMPLE_OID_BYTES).unwrap();
83        assert_eq!(EXAMPLE_OID, oid);
84    }
85
86    #[test]
87    fn encode() {
88        let mut buffer = [0u8; 8];
89        assert_eq!(
90            EXAMPLE_OID_BYTES,
91            EXAMPLE_OID.encode_to_slice(&mut buffer).unwrap()
92        );
93    }
94
95    #[test]
96    fn length() {
97        // Ensure an infallible `From` conversion to `Any` will never panic
98        assert!(ObjectIdentifier::MAX_SIZE <= Length::MAX.try_into().unwrap());
99    }
100}
der/asn1/oid.rs

der/asn1/
oid.rs
