zerec 0.3.0

Minimal zero-copy binary codec for Rust.
Documentation 
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

//! Encode + Decode for string types.

use alloc::string::String;
use alloc::borrow::ToOwned;
use crate::{
    codec::{Decode, Encode},
    decoder::BufDecoder,
    encoder::BufEncoder,
    error::DecodeError
};

// ── String ────────────────────────────────────────────────────────────────
impl Encode for String {
    /// Wire layout: `u32` byte length, then raw UTF-8 bytes.
    fn encode(&self, enc: &mut BufEncoder) {
        let b = self.as_bytes();
        enc.write_u32(u32::try_from(b.len()).expect("String byte length exceeds u32::MAX"));
        enc.write_bytes(b);
    }
}

impl Decode for String {
    fn decode(dec: &mut BufDecoder<'_>) -> Result<Self, DecodeError> {
        let len = dec.read_u32()?;
        let limit = dec.collection_limit();

        if len > limit {
            return Err(DecodeError::CollectionTooLarge { len, limit });
        }

        let bytes = dec.read_bytes(len as usize)?;
        core::str::from_utf8(bytes)
            .map(|s| s.to_owned())
            .map_err(|_| DecodeError::InvalidUtf8)
    }
}

// ── &str (encode only) ────────────────────────────────────────────────────

impl Encode for str {
    /// Same wire layout as `String`.
    /// `Decode for &str` is not provided here — use [`crate::ZeroBuf`]
    /// to borrow directly from the source buffer without allocating.
    fn encode(&self, enc: &mut BufEncoder) {
        let b = self.as_bytes();
        enc.write_u32(b.len() as u32);
        enc.write_bytes(b);
    }
}

impl Encode for &str {
    #[inline]
    fn encode(&self, enc: &mut BufEncoder) {
        (**self).encode(enc);
    }
}