cesr-rs 0.11.0

CESR + KERI primitives for Rust as a single feature-gated, no_std-capable crate
Documentation 
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use core::fmt;

use crate::core::matter::code::NumberCode;
use crate::core::primitives::ordinal::Ordinal;

/// An unsigned integer with an automatically selected CESR number code.
///
/// Ordering is lexicographic over `(code, value)`; because `NumberCode` is
/// size-ascending and `Number::new` selects the code monotonically from the
/// value, canonical numbers order by magnitude — matching the ordinal use.
#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
pub struct Number {
    code: NumberCode,
    value: u128,
}

impl Number {
    /// Creates a `Number` choosing the smallest code that fits `value`.
    #[must_use]
    pub const fn new(value: u128) -> Self {
        let code = NumberCode::for_value(value);
        Self { code, value }
    }

    /// Creates a `Number` with an explicitly specified code.
    #[must_use]
    pub const fn with_code(code: NumberCode, value: u128) -> Self {
        Self { code, value }
    }

    /// Returns the CESR number code for this value.
    #[must_use]
    pub const fn code(&self) -> &NumberCode {
        &self.code
    }

    /// Returns the raw integer value.
    #[must_use]
    pub const fn value(&self) -> u128 {
        self.value
    }
}

impl fmt::LowerHex for Number {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        fmt::LowerHex::fmt(&self.value, f)
    }
}

impl Ordinal for Number {
    fn num(&self) -> u128 {
        self.value
    }
}

#[cfg(test)]
mod tests {
    use alloc::format;
    use alloc::string::ToString;

    use super::*;
    use crate::core::matter::code::NumberCode;

    #[test]
    fn number_picks_smallest_code() {
        let n_short = Number::new(255);
        assert_eq!(*n_short.code(), NumberCode::Short);
        assert_eq!(n_short.value(), 255);

        let n_long = Number::new(0xFFFF_FFFF);
        assert_eq!(*n_long.code(), NumberCode::Long);

        let n_big = Number::new(u128::from(u64::MAX));
        assert_eq!(*n_big.code(), NumberCode::Big);
    }

    #[test]
    fn number_zero() {
        let n = Number::new(0);
        assert_eq!(*n.code(), NumberCode::Short);
        assert_eq!(n.value(), 0);
    }

    #[test]
    fn number_renders_minimal_hex_via_ordinal_and_lowerhex() {
        let n = Number::new(255);
        assert_eq!(n.numh().to_string(), "ff");
        assert_eq!(format!("{n:x}"), "ff");
        assert_eq!(Number::new(0).numh().to_string(), "0");
        assert_eq!(Number::new(u128::MAX).num(), u128::MAX);
    }

    #[test]
    fn number_is_copy() {
        fn assert_copy<T: Copy>() {}
        assert_copy::<Number>();
    }
}