der/
encodable.rs

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1//! Trait definition for [`Encodable`].
2
3use crate::{EncodeValue, Encoder, Length, Result, Tagged};
4
5#[cfg(feature = "alloc")]
6use {crate::ErrorKind, alloc::vec::Vec, core::iter};
7
8/// Encoding trait.
9pub trait Encodable {
10    /// Compute the length of this value in bytes when encoded as ASN.1 DER.
11    fn encoded_len(&self) -> Result<Length>;
12
13    /// Encode this value as ASN.1 DER using the provided [`Encoder`].
14    fn encode(&self, encoder: &mut Encoder<'_>) -> Result<()>;
15
16    /// Encode this value to the provided byte slice, returning a sub-slice
17    /// containing the encoded message.
18    fn encode_to_slice<'a>(&self, buf: &'a mut [u8]) -> Result<&'a [u8]> {
19        let mut encoder = Encoder::new(buf);
20        self.encode(&mut encoder)?;
21        encoder.finish()
22    }
23
24    /// Encode this message as ASN.1 DER, appending it to the provided
25    /// byte vector.
26    #[cfg(feature = "alloc")]
27    #[cfg_attr(docsrs, doc(cfg(feature = "alloc")))]
28    fn encode_to_vec(&self, buf: &mut Vec<u8>) -> Result<Length> {
29        let expected_len = usize::try_from(self.encoded_len()?)?;
30        buf.reserve(expected_len);
31        buf.extend(iter::repeat(0).take(expected_len));
32
33        let mut encoder = Encoder::new(buf);
34        self.encode(&mut encoder)?;
35        let actual_len = encoder.finish()?.len();
36
37        if expected_len != actual_len {
38            return Err(ErrorKind::Incomplete {
39                expected_len: expected_len.try_into()?,
40                actual_len: actual_len.try_into()?,
41            }
42            .into());
43        }
44
45        actual_len.try_into()
46    }
47
48    /// Serialize this message as a byte vector.
49    #[cfg(feature = "alloc")]
50    #[cfg_attr(docsrs, doc(cfg(feature = "alloc")))]
51    fn to_vec(&self) -> Result<Vec<u8>> {
52        let mut buf = Vec::new();
53        self.encode_to_vec(&mut buf)?;
54        Ok(buf)
55    }
56}
57
58impl<T> Encodable for T
59where
60    T: EncodeValue + Tagged,
61{
62    /// Compute the length of this value in bytes when encoded as ASN.1 DER.
63    fn encoded_len(&self) -> Result<Length> {
64        self.value_len().and_then(|len| len.for_tlv())
65    }
66
67    /// Encode this value as ASN.1 DER using the provided [`Encoder`].
68    fn encode(&self, encoder: &mut Encoder<'_>) -> Result<()> {
69        self.header()?.encode(encoder)?;
70        self.encode_value(encoder)
71    }
72}
der/encodable.rs

der/
encodable.rs
