cbor-core

A Rust implementation of CBOR::Core, the deterministic subset of CBOR (RFC 8949).

This crate encodes and decodes CBOR using owned data structures rather than Serde traits. Values can be constructed, inspected, and modified directly, which is a better fit when the goal is to work with CBOR as a data format in its own right rather than as a serialization layer for Rust types.

This is the first public review of the library. The API is not yet stable and may change in future releases.

Status

The implementation targets draft-rundgren-cbor-core-25 and passes all test vectors from Appendix A of that specification, including rejection of non-deterministic encodings.

Supported types: integers (including arbitrary-precision via tags 2 and 3), IEEE 754 floats (half, single, double), byte strings, text strings, arrays, maps, tagged values, and simple values (null, booleans).

Encoding is deterministic: integers and floats use their shortest form, and map keys are sorted in canonical order. NaN values, including signaling NaNs and custom payloads, are preserved through round-trips.

Not yet implemented: CBOR::Core diagnostic notation, Int53, DateTime/EpochTime wrappers, and optional integrations with external crates (num_bigint, half, time, chrono).

Usage

use cbor_core::{Value, array, map};

let value = map! {
    1 => "hello",
    2 => array![10, 20, 30],
};

let bytes = value.encode();
let decoded = Value::decode(&bytes).unwrap();
assert_eq!(value, decoded);

Arrays and maps can also be built from standard Rust collections (Vec, BTreeMap, HashMap, slices of pairs), and values can be modified in place through the as_*_mut() accessors. See the documentation on Value for the full API.

License

MIT