messagepack_core/decode/
nil.rs

1use super::{Decode, Error, Result};
2use crate::formats::Format;
3
4pub struct NilDecoder;
5
6impl<'a> Decode<'a> for NilDecoder {
7    type Value = ();
8    fn decode(buf: &'a [u8]) -> Result<(Self::Value, &'a [u8])> {
9        let (format, buf) = Format::decode(buf)?;
10
11        match format {
12            Format::Nil => Ok(((), buf)),
13            _ => Err(Error::UnexpectedFormat),
14        }
15    }
16
17    fn decode_with_format(format: Format, buf: &'a [u8]) -> Result<(Self::Value, &'a [u8])> {
18        let _ = format;
19        Ok(((), buf))
20    }
21}
22
23impl<'a> Decode<'a> for () {
24    type Value = ();
25    fn decode(buf: &'a [u8]) -> Result<(Self::Value, &'a [u8])> {
26        NilDecoder::decode(buf)
27    }
28    fn decode_with_format(format: Format, buf: &'a [u8]) -> Result<(Self::Value, &'a [u8])> {
29        NilDecoder::decode_with_format(format, buf)
30    }
31}
32
33impl<'a, V> Decode<'a> for Option<V>
34where
35    V: Decode<'a>,
36{
37    type Value = Option<V::Value>;
38    fn decode(buf: &'a [u8]) -> Result<(Self::Value, &'a [u8])> {
39        let (format, buf) = Format::decode(buf)?;
40        Self::decode_with_format(format, buf)
41    }
42    fn decode_with_format(format: Format, buf: &'a [u8]) -> Result<(Self::Value, &'a [u8])> {
43        match format {
44            Format::Nil => Ok((None, buf)),
45            other => {
46                let (val, buf) = V::decode_with_format(other, buf)?;
47                Ok((Some(val), buf))
48            }
49        }
50    }
51}
52
53#[cfg(test)]
54mod tests {
55    use super::*;
56
57    #[test]
58    fn decode_nil() {
59        let buf: &[u8] = &[0xc0];
60        let (_, rest) = NilDecoder::decode(buf).unwrap();
61        assert_eq!(rest.len(), 0);
62    }
63
64    #[test]
65    fn decode_option() {
66        let buf: &[u8] = &[0xc0];
67        let (decoded, rest) = Option::<bool>::decode(buf).unwrap();
68        assert_eq!(decoded, None);
69        assert_eq!(rest.len(), 0);
70
71        let buf: &[u8] = &[0xc3];
72        let (decoded, rest) = Option::<bool>::decode(buf).unwrap();
73        assert_eq!(decoded, Some(true));
74        assert_eq!(rest.len(), 0);
75    }
76}
messagepack_core/decode/nil.rs

messagepack_core/decode/
nil.rs
