medius 3.4.3

Host control library for the medius transparent mouse passthrough box
Documentation
//! Decoded `RESP(RATE)`: the live native report rate (§4.5).

use crate::protocol::opcode::{RATE_CHANGE_DRIVEN, RATE_CONFIDENT};

/// Live native report rate, tracked from the report stream, and the cloned poll period.
#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
pub struct Rate {
    /// Realised native report period in µs (`0` = not learned yet, or N/A for a change-driven input).
    pub native_period_us: u16,
    /// Cloned inject-endpoint `bInterval` poll period in µs (the active input's endpoint).
    pub poll_period_us: u16,
    /// Estimator window is full, so the value is trustworthy (mirrors HEALTH `rate_confident`).
    pub confident: bool,
    /// The active input is change-driven (keyboard/media): no continuous cadence, poll floor only.
    pub change_driven: bool,
}

impl Rate {
    /// Native report rate in Hz; `None` with no continuous cadence.
    pub fn native_hz(&self) -> Option<f32> {
        if self.native_period_us == 0 {
            None
        } else {
            Some(1_000_000.0 / f32::from(self.native_period_us))
        }
    }

    /// `[what][native_period_us u16][poll_period_us u16][flags u8]` (§4.5).
    pub(crate) fn from_payload(p: &[u8]) -> Option<Self> {
        if p.len() < 6 {
            return None;
        }
        Some(Rate {
            native_period_us: u16::from_le_bytes([p[1], p[2]]),
            poll_period_us: u16::from_le_bytes([p[3], p[4]]),
            confident: p[5] & RATE_CONFIDENT != 0,
            change_driven: p[5] & RATE_CHANGE_DRIVEN != 0,
        })
    }
}