Recipes

Runnable code: sbe-feature-tour src/lib.rs.

• Aeron try_claim
• Display / Debug
• Schema Descriptions → Rustdoc
• Domain DTOs
• App Types on Composites
• Timestamp Conversions

Quick reference

Known vs unknown group count:

#![allow(unused)]
fn main() {
pub fn encode_sample_car(buf: &mut [u8]) -> Result<usize, sbe_rt::EncodeError> {
    let mut extras = OptionalExtras::default();
    extras.cruise_control(true).sports_pack(true);

    // Buffer pre-sized from EncodedLength; try_* still validates extent.
    let len = CarEncoder::try_wrap_and_apply_header(buf, 0)
        .unwrap()
        .fixed(&CarFixedFields {
            serial_number: 1234,
            model_year: 2013,
            available: true.into(),
            code: Model::A,
            some_numbers: [10, 20, 30, 40],
            vehicle_code: [b'A', b'B', b'C', b'D', b'E', b'F'],
            extras,
            engine: Engine::new(
                2000,
                4,
                [b'1', b'2', b'3'],
                0i8,
                false.into(),
                Booster::new(BoostType::TURBO, 210),
            ),
        })
        .fuel_figures(2, |g| {
            g.add(|mut e| {
                e.speed(30).mpg(35.9);
                e.usage_description_as_str("Urban")
            })?;
            g.add(|mut e| {
                e.speed(60).mpg(25.0);
                e.usage_description_as_str("Highway")
            })?;
            Ok(())
        })?
        .performance_figures(1, |g| {
            g.add(|mut e| {
                e.octane_rating(95);
                e.acceleration(2, |a| {
                    a.add(|x| {
                        x.mph(30).seconds(4.0);
                        Ok(())
                    })?;
                    a.add(|x| {
                        x.mph(60).seconds(7.5);
                        Ok(())
                    })
                })
            })?;
            Ok(())
        })?
        .manufacturer_as_str("Honda")?
        .model_as_str("Civic VTi")?
        .activation_code_as_str("abcdef")?
        .encoded_length_with_header();

    Ok(len)
}
}

(From sbe-feature-tour — known-count groups with chaining, tested in CI.)

Unknown size: count back-patched after the closure (streaming producers).

let unknown_len = CarEncoder::wrap_and_apply_header(&mut buf, 0)
    .fixed(&fields)
    .fuel_figures_unknown_size(|g| {
        for row in rows {
            g.add(|mut e| {
                e.speed(row.speed).mpg(row.mpg);
                e.usage_description_as_str(&row.usage)
            })?;
        }
        Ok(())
    })?
    .performance_figures(0, |_| Ok(()))?
    .manufacturer_as_str("Honda")?
    .model_as_str("Civic")?
    .activation_code_as_str("active")?
    .encoded_length_with_header();

println!("known={known_len} unknown={unknown_len}");