mdns-proto 0.2.0

//! CNAME record (canonical name, RFC 1035 §3.3.1).
//!
//! CNAME rdata is exactly one domain name — structurally identical to PTR —
//! so it is parsed and canonicalized the same way (decompressed for storage,
//! case-folded for identity).

use crate::{error::ParseError, wire::NameRef};

/// Parsed CNAME record rdata.
#[derive(Debug, Copy, Clone, Eq, PartialEq, Hash)]
pub struct Cname<'a> {
  target: NameRef<'a>,
}

impl<'a> Cname<'a> {
  /// Parses a CNAME record's rdata. `message` is the full DNS message so
  /// compression pointers can resolve; `rdata_offset` is the start of the
  /// rdata bytes within it; `rdata_len` is the declared RDLENGTH.
  ///
  /// Like PTR: the encoded name MUST consume EXACTLY
  /// `rdata_len` bytes — neither overrun the declared boundary nor leave
  /// trailing garbage inside it.
  pub fn try_from_message(
    message: &'a [u8],
    rdata_offset: usize,
    rdata_len: usize,
  ) -> Result<Self, ParseError> {
    let (target, consumed) = NameRef::try_parse(message, rdata_offset)?;
    if consumed != rdata_len {
      return Err(ParseError::BufferTooShort(
        crate::error::BufferTooShortDetail::new(consumed, rdata_offset, rdata_len),
      ));
    }
    Ok(Self { target })
  }

  /// Returns the canonical target name.
  #[inline(always)]
  pub const fn target(&self) -> &NameRef<'a> {
    &self.target
  }
}

#[cfg(test)]
#[allow(clippy::unwrap_used)]
mod tests;