1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
|
//! The [`Sequence`] trait simplifies writing decoders/encoders which map ASN.1
//! `SEQUENCE`s to Rust structs.
use crate::{
ByteSlice, Decode, DecodeValue, Encode, EncodeValue, FixedTag, Header, Length, Reader, Result,
Tag, Writer,
};
/// ASN.1 `SEQUENCE` trait.
///
/// Types which impl this trait receive blanket impls for the [`Decode`],
/// [`Encode`], and [`FixedTag`] traits.
pub trait Sequence<'a>: Decode<'a> {
/// Call the provided function with a slice of [`Encode`] trait objects
/// representing the fields of this `SEQUENCE`.
///
/// This method uses a callback because structs with fields which aren't
/// directly [`Encode`] may need to construct temporary values from
/// their fields prior to encoding.
fn fields<F, T>(&self, f: F) -> Result<T>
where
F: FnOnce(&[&dyn Encode]) -> Result<T>;
}
impl<'a, M> EncodeValue for M
where
M: Sequence<'a>,
{
fn value_len(&self) -> Result<Length> {
self.fields(|fields| {
fields
.iter()
.try_fold(Length::ZERO, |acc, field| acc + field.encoded_len()?)
})
}
fn encode_value(&self, writer: &mut dyn Writer) -> Result<()> {
self.fields(|fields| {
for &field in fields {
field.encode(writer)?;
}
Ok(())
})
}
}
impl<'a, M> FixedTag for M
where
M: Sequence<'a>,
{
const TAG: Tag = Tag::Sequence;
}
/// The [`SequenceRef`] type provides raw access to the octets which comprise a
/// DER-encoded `SEQUENCE`.
///
/// This is a zero-copy reference type which borrows from the input data.
pub struct SequenceRef<'a> {
/// Body of the `SEQUENCE`.
body: ByteSlice<'a>,
}
impl<'a> DecodeValue<'a> for SequenceRef<'a> {
fn decode_value<R: Reader<'a>>(reader: &mut R, header: Header) -> Result<Self> {
Ok(Self {
body: ByteSlice::decode_value(reader, header)?,
})
}
}
impl EncodeValue for SequenceRef<'_> {
fn value_len(&self) -> Result<Length> {
Ok(self.body.len())
}
fn encode_value(&self, writer: &mut dyn Writer) -> Result<()> {
self.body.encode_value(writer)
}
}
impl<'a> FixedTag for SequenceRef<'a> {
const TAG: Tag = Tag::Sequence;
}
|
