nimble-derive 0.2.0

Async friendly, simple and fast binary encoding/decoding


Async friendly, simple and fast binary encoding/decoding in Rust.

Binary encoding scheme

This crate uses a minimal binary encoding scheme. For example, consider the following struct:

struct MyStruct {
    a: u8,
    b: u16,

encode() will serialize this into Vec of size 3 (which is the sum of sizes of u8 and u16).

Similarly, for types which can have dynamic size (Vec, String, etc.), encode() prepends the size of encoded value as u64.


Add nimble in your Cargo.toml's dependencies section:

nimble = { version = "0.2", features = ["derive"] }

Or, if you are in an environment based on tokio, use:

nimble = { version = "0.2", default-features = false, features = ["derive", "tokio"] }

For encoding and decoding, any type must implement two traits provided by this crate, i.e., Encode and Decode. For convenience, nimble provides derive macros (only when "derive" feature is enabled) to implement these traits.

use nimble::{Encode, Decode};

#[derive(Encode, Decode)]
struct MyStruct {
    a: u8,
    b: u16,

Now you can use encode() and decode() functions to encode and decode values of MyStruct. In addition to this, you can also use MyStruct::encode_to() function to encode values directly to a type implementing AsyncWrite and MyStruct::decode_from() function to decode values directly from a type implementing AsyncRead.

Note: Most of the functions exposed by this crate are async functions and returns Future values. So, you'll need an executor to drive the Future returned from these functions. async-std and tokio are two popular options.


  • futures: Select this feature when you want to implement Encode and Decode using futures' AsyncRead/AsyncWrite traits.
    • Enabled by default.
  • tokio: Select this feature when you want to implement Encode and Decode using tokio's AsyncRead/AsyncWrite traits.
    • Disabled by default.
  • derive: Enables derive macros for implementing Encode and Decode traits.
    • Disabled by default.

Note: Features futures and tokio are mutually exclusive, i.e., only one of them can be enabled at a time. Compilation will fail if either both of them are enabled or none of them are enabled.


Licensed under either of

at your option.


Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.