# loro-protocol (Rust)
Rust implementation of the Loro syncing protocol encoder/decoder. Mirrors the TypeScript package in `packages/loro-protocol` and follows the wire format described in `protocol.md` and the end-to-end encrypted flow in `protocol-e2ee.md`.
## Features
- Encode/decode Join, DocUpdate, FragmentHeader/Fragment, UpdateError, and Leave messages
- 256 KiB message size guard to match the wire spec
- Bytes utilities (`BytesWriter`, `BytesReader`) for varint/varbytes/varstring
- `%ELO` container parsing; Rust-side encryption helpers are WIP and may evolve
## Usage
Add the crate to your workspace (published crate name matches the package):
```bash
cargo add loro-protocol
```
Encode and decode messages:
```rust
use loro_protocol::{encode, decode, ProtocolMessage, CrdtType};
let msg = ProtocolMessage::JoinRequest {
crdt: CrdtType::Loro,
room_id: "room-123".to_string(),
auth: vec![],
version: vec![],
};
let bytes = encode(&msg)?;
let roundtrip = decode(&bytes)?;
assert_eq!(roundtrip, msg);
```
Streaming-friendly decode:
```rust
use loro_protocol::try_decode;
let buf = /* bytes from the wire */;
if let Some(msg) = try_decode(&buf) {
// valid message
} else {
// malformed or incomplete buffer
}
```
## Tests
```bash
cargo test -p loro-protocol
```
## Spec References
- `protocol.md` for the wire format and message semantics
- `protocol-e2ee.md` for %ELO encryption details