asn1r

Experimental import using bindgen (FFI) of asn1c, one of the most feature-rich open-source ASN.1 compilers, into Rust. Should in principle support any ASN.1 feature that asn1c supports.

It compiles ASN.1 definitions into Rust structs, also accompanied with encoding/decoding methods.

Usage

Building

asn1c is required to be installed, namely the more up-to-date @mouse07410's fork which provides various bugfixes and features.

Configuration of the compiler is currently done through config.toml. Currently asn1c parameters, such as the ASN.1 definition files to be compiled can be defined in this file.

To build the library simply run cargo build. Some tests can be performed with cargo test.

Library

While the original C functions are available, this project also provides a more friendly interface.

Consider the provided Dog definition provided in asn1/example.asn1.

Encoding (JSON here) works as such,

// Declare a buffer to store our encoded output
let mut data = vec![0u8; 1024];

// Declare a Default Dog
let mut dog = Dog::default();
// Fill the Dog
dog.name.fill("Fido");
dog.canSwim = 0;
dog.age = 9;
dog.breed = Breed::labrador as i64;
dog.favouriteFood.present = Food_PR::wet;
dog.favouriteFood.choice.wet.brand.fill("Yummy");
dog.favouriteFood.choice.wet.moisturePercentage = 80;
dog.favouriteFood.choice.wet.priceKg = 12;
// Encode the Dog
let renc = dog.encode(EncodingRules::jer, &mut data).unwrap();
println!("Encoded {} bytes:\n{}", renc, show(&data));

with an output:

Encoded 233 bytes:
{
    "name": "Fido",
    "age": 9,
    "breed": "labrador",
    "favouriteFood": {
        "wet": {
            "brand": "Yummy",
            "moisturePercentage": 80,
            "priceKg": 12
        }
    },
    "canSwim": true
}

Decoding is also straightforward,

// Declare the Dog to be filled
let mut clone = Dog::default();
// Decode
let rdec = clone.decode(EncodingRules::jer, &data).unwrap();
println!("Decoded OK! Consumed {} bytes", rdec);

with an output, Decoded OK! Consumed 233 bytes.

Current implemented tests expect the above definition to be compiled.

Acknowledgements

Special thanks to @sjames for his exploratory work. If you are into Rust and automotive-related software check him out.