le_stream/
from_le_stream.rs

1use crate::{Error, Result};
2
3mod alloc;
4mod core;
5mod heapless;
6mod intx;
7mod macaddr;
8
9/// Parses a value from a stream of little-endian bytes.
10///
11/// Implementations read exactly the bytes required to construct `Self` and
12/// leave any remaining bytes in the input iterator. Use
13/// [`from_le_stream_exact`](Self::from_le_stream_exact) when trailing bytes
14/// should be treated as an error.
15pub trait FromLeStream: Sized {
16    /// Parses a value from the front of a little-endian byte stream.
17    ///
18    /// The method returns [`None`] when the stream ends before a complete value
19    /// can be decoded. Implementations may leave unread bytes in `bytes` after
20    /// successfully decoding one value.
21    ///
22    /// # Examples
23    ///
24    /// ```
25    /// use le_stream::FromLeStream;
26    ///
27    /// let mut bytes = [0x34, 0x12, 0xFF].into_iter();
28    ///
29    /// assert_eq!(u16::from_le_stream(&mut bytes), Some(0x1234));
30    /// assert_eq!(bytes.next(), Some(0xFF));
31    /// ```
32    fn from_le_stream<T>(bytes: T) -> Option<Self>
33    where
34        T: Iterator<Item = u8>;
35
36    /// Parses a value from a little-endian byte stream and requires exhaustion.
37    ///
38    /// # Errors
39    ///
40    /// Returns [`Error::UnexpectedEndOfStream`] if the stream ends before a
41    /// complete value can be decoded, or [`Error::StreamNotExhausted`] if a
42    /// value was decoded but more bytes remain.
43    fn from_le_stream_exact<T>(mut bytes: T) -> Result<Self>
44    where
45        T: Iterator<Item = u8>,
46    {
47        let instance = Self::from_le_stream(&mut bytes).ok_or(Error::UnexpectedEndOfStream)?;
48
49        if let Some(next_byte) = bytes.next() {
50            Err(Error::StreamNotExhausted {
51                instance,
52                next_byte,
53            })
54        } else {
55            Ok(instance)
56        }
57    }
58
59    /// Parses a value from a little-endian byte slice and requires exhaustion.
60    ///
61    /// # Errors
62    ///
63    /// Returns an [`Error`] if the slice is too short or contains bytes after
64    /// the decoded value.
65    fn from_le_slice(bytes: &[u8]) -> Result<Self> {
66        Self::from_le_stream_exact(bytes.iter().copied())
67    }
68}
le_stream/from_le_stream.rs

le_stream/
from_le_stream.rs
