dvb_common/
traits.rs

1//! Canonical `Parse` and `Serialize` traits for the DVB crate family.
2//!
3//! Each implementer picks its own error type via `type Error`, so
4//! domain-specific error variants stay visible to the caller.
5
6use alloc::vec::Vec;
7
8/// Parse a DVB structure from raw bytes. Borrowing allowed via `<'a>`; the
9/// concrete error type is chosen per implementer.
10pub trait Parse<'a>: Sized {
11    /// The error type this implementer returns. Typically the enclosing
12    /// crate's `Error` enum.
13    type Error;
14
15    /// Parse `bytes` as `Self`. Returns `Err(Self::Error)` on any protocol
16    /// violation or buffer underrun.
17    fn parse(bytes: &'a [u8]) -> Result<Self, Self::Error>;
18}
19
20/// Serialize a DVB structure back to bytes. Split from [`Parse`] so owned
21/// and borrowed variants of the same type can implement `Serialize`
22/// without carrying a lifetime.
23pub trait Serialize {
24    /// The error type this implementer returns (usually the same as the
25    /// corresponding [`Parse`] impl, but need not be).
26    type Error;
27
28    /// Number of bytes `serialize_into` will write.
29    fn serialized_len(&self) -> usize;
30
31    /// Write the serialised form into `buf`. Returns the number of bytes
32    /// written (always equal to `serialized_len()`).
33    fn serialize_into(&self, buf: &mut [u8]) -> Result<usize, Self::Error>;
34
35    /// Convenience: allocate a `Vec` and serialise into it.
36    ///
37    /// # Panics
38    /// Panics if `serialize_into` returns an error on a buffer of exactly
39    /// `serialized_len()` bytes. For values obtained by parsing real wire data
40    /// this never happens; it can only occur for a **hand-constructed** value
41    /// that violates a wire constraint (e.g. a section whose body exceeds the
42    /// 12-bit `section_length`). When building values by hand and that's a
43    /// possibility, call [`serialize_into`](Self::serialize_into) and handle the
44    /// error instead.
45    fn to_bytes(&self) -> Vec<u8>
46    where
47        Self::Error: core::fmt::Debug,
48    {
49        let mut v = alloc::vec![0u8; self.serialized_len()];
50        self.serialize_into(&mut v)
51            .expect("serialize_into must succeed when buffer is exactly serialized_len()");
52        v
53    }
54}
dvb_common/traits.rs

dvb_common/
traits.rs
