kevy-bytes

A 24-byte small-byte-string (SmallBytes) with inline SSO — pure Rust, zero dependencies, alloc-free for payloads ≤ 22 bytes.

Part of kevy, a single-machine, Redis-compatible key–value server, but designed to stand alone wherever you want short bytes stored without an extra pointer chase.

• Inline up to 22 bytes — payload + tag-byte stored directly inside the 24-byte union; no allocation, no heap pointer.
• Heap path for longer — same external API; switches to a length-prefixed heap buffer transparently.
• 24-byte size & usize alignment are const-asserted (won't compile if violated).
• Zero dependencies. Only kevy-hash (path dep, also pure Rust) for the optional Hash impl.

use kevy_bytes::SmallBytes;

let inline = SmallBytes::from_slice(b"redis");   // 5 ≤ 22 → no alloc
let heap   = SmallBytes::from_slice(&[0u8; 64]); // 64 > 22 → one alloc
assert_eq!(inline.as_slice(), b"redis");
assert_eq!(heap.len(), 64);

Safety

The SSO union needs unsafe for the tag-byte read; every unsafe block in the crate has a SAFETY: comment justifying the union discriminant. It is LE-only (compile-time guarded by compile_error! on BE targets).

License

MIT OR Apache-2.0