bela 0.3.0

Safe Rust API for real-time audio on Bela Gem
Documentation 
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//! Ports of the Wiring-style convenience helpers from `Utilities.h`.

/// Linearly rescales `x` from the range `in_min..in_max` to
/// `out_min..out_max`. Values outside the input range are extrapolated.
#[must_use]
pub fn map(x: f32, in_min: f32, in_max: f32, out_min: f32, out_max: f32) -> f32 {
    (x - in_min) * (out_max - out_min) / (in_max - in_min) + out_min
}

/// Clips `x` to the range `min_val..max_val`.
///
/// Deliberately not `f32::clamp`: `clamp` panics when
/// `min_val > max_val` (or when a bound is NaN), while the C original
/// returns a value for any input. This port keeps the C semantics and
/// stays panic-free, which matters on the real-time render path where
/// a panic aborts the whole process.
#[must_use]
pub fn constrain(x: f32, min_val: f32, max_val: f32) -> f32 {
    if x < min_val {
        min_val
    } else if x > max_val {
        max_val
    } else {
        x
    }
}

#[cfg(test)]
#[allow(
    clippy::float_cmp,
    reason = "tests compare exactly representable values"
)]
mod tests {
    use super::*;

    #[test]
    fn map_rescales_and_extrapolates() {
        assert_eq!(map(0.5, 0.0, 1.0, 0.0, 10.0), 5.0);
        assert_eq!(map(0.0, -1.0, 1.0, 0.0, 4.0), 2.0);
        // Outside the input range: extrapolated, not clipped.
        assert_eq!(map(2.0, 0.0, 1.0, 0.0, 10.0), 20.0);
        // Inverted output range.
        assert_eq!(map(0.25, 0.0, 1.0, 1.0, 0.0), 0.75);
    }

    #[test]
    fn constrain_clips_to_the_range() {
        assert_eq!(constrain(0.5, 0.0, 1.0), 0.5);
        assert_eq!(constrain(-0.5, 0.0, 1.0), 0.0);
        assert_eq!(constrain(1.5, 0.0, 1.0), 1.0);
    }
}