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//! Payload encode/decode for [`Packet`], byte-exact per protocol v1.
use crate::packet::*;
use crate::wire::{Reader, Writer};
use crate::Error;
impl<'a> Packet<'a> {
/// Type byte on the wire.
pub fn ty(&self) -> u8 {
match self {
Self::Hello(_) => ty::HELLO,
Self::ImuBatch(_) => ty::IMU_BATCH,
Self::Baro(_) => ty::BARO,
Self::Mag(_) => ty::MAG,
Self::Trigger(_) => ty::TRIGGER,
Self::Pps(_) => ty::PPS,
Self::GnssRaw(_) => ty::GNSS_RAW,
Self::RtcmIn(_) => ty::RTCM_IN,
Self::Config(_) => ty::CONFIG,
Self::Health(_) => ty::HEALTH,
Self::Unknown { ty, .. } => *ty,
}
}
/// Payload length in bytes, validated against the per-type limits.
pub fn payload_len(&self) -> Result<usize, Error> {
Ok(match self {
Self::Hello(_) => HELLO_LEN,
Self::ImuBatch(b) => {
let n = b.samples.len();
if n == 0 || n > IMU_MAX_SAMPLES {
return Err(Error::ImuCount);
}
IMU_HEADER_LEN + IMU_SAMPLE_LEN * n
}
Self::Baro(_) => BARO_LEN,
Self::Mag(_) => MAG_LEN,
Self::Trigger(_) => TRIGGER_LEN,
Self::Pps(_) => PPS_LEN,
Self::GnssRaw(g) if g.bytes.len() > GNSS_MAX_BYTES => return Err(Error::Length),
Self::GnssRaw(g) => GNSS_HEADER_LEN + g.bytes.len(),
Self::RtcmIn(r) if r.bytes.len() > RTCM_MAX_BYTES => return Err(Error::Length),
Self::RtcmIn(r) => RTCM_HEADER_LEN + r.bytes.len(),
Self::Config(_) => CONFIG_LEN,
Self::Health(_) => HEALTH_LEN,
Self::Unknown { payload, .. } if payload.len() > crate::MAX_PAYLOAD => {
return Err(Error::Length)
}
Self::Unknown { payload, .. } => payload.len(),
})
}
/// Write the payload into `out` (exactly `payload_len()` bytes).
pub(crate) fn write_payload(&self, out: &mut [u8]) {
let mut w = Writer::new(out);
match self {
Self::Hello(h) => {
w.u16(h.proto_ver);
w.u8(h.fw_major);
w.u8(h.fw_minor);
w.u8(h.fw_patch);
w.zeros(1);
w.u16(h.board_id);
w.u32(h.caps);
w.bytes(&h.uid);
w.bytes(&h.board_name);
}
Self::ImuBatch(b) => {
w.u64(b.t0_ns);
w.u32(b.dt_ns);
// payload_len() has bounded the count to 1..=64.
w.u8(b.samples.len() as u8);
w.u8(b.imu_id);
w.u8(b.flags);
w.zeros(1);
w.u32(b.seq0);
for s in b.samples.iter() {
s.write(&mut w);
}
}
Self::Baro(b) => {
w.u64(b.t_ns);
w.f32(b.pressure_pa);
w.f32(b.temp_c);
w.u8(b.baro_id);
w.zeros(3);
}
Self::Mag(m) => {
w.u64(m.t_ns);
m.field_ut.iter().for_each(|v| w.f32(*v));
w.u8(m.mag_id);
w.zeros(3);
}
Self::Trigger(t) => {
w.u32(t.seq);
w.u8(t.cam_mask);
w.u8(t.flags);
w.zeros(2);
w.u64(t.t_start_ns);
w.u64(t.t_mid_ns);
w.u32(t.exposure_ns);
}
Self::Pps(p) => {
w.u64(p.t_ns);
w.u8(p.locked);
w.zeros(3);
w.u32(p.pps_count);
w.i32(p.phase_err_ns);
w.i32(p.freq_corr_ppb);
}
Self::GnssRaw(g) => {
w.u64(g.t_ns);
w.u8(g.port);
w.zeros(1);
w.bytes(g.bytes);
}
Self::RtcmIn(r) => {
w.u8(r.port);
w.zeros(1);
w.bytes(r.bytes);
}
Self::Config(c) => {
w.u16(c.trigger_hz);
w.u32(c.exposure_us);
w.u16(c.imu_odr_hz);
w.u8(c.cam_mask);
w.u8(c.trigger_mode);
w.u8(c.pps_out);
w.u8(c.gprmc_out);
w.u8(c.imu_batch);
w.i8(c.heater_target_c);
w.zeros(2);
}
Self::Health(h) => {
w.u64(h.t_ns);
w.u32(h.uptime_s);
w.i16(h.mcu_temp_c);
w.i16(h.imu_temp_c);
w.u16(h.vin_mv);
w.zeros(2);
w.u32(h.usb_tx_drops);
w.u32(h.imu_fifo_overflows);
w.u32(h.rx_crc_errors);
w.u32(h.trigger_missed);
w.u8(h.pps_state);
w.u8(h.heater_duty_pct);
w.zeros(2);
}
Self::Unknown { payload, .. } => w.bytes(payload),
}
debug_assert_eq!(w.pos(), out.len());
}
/// Parse a payload of type `ty`.
pub fn parse(ty: u8, p: &'a [u8]) -> Result<Self, Error> {
let fixed = |n: usize| {
if p.len() == n {
Ok(())
} else {
Err(Error::PayloadSize { ty })
}
};
let mut r = Reader::new(p);
Ok(match ty {
ty::HELLO => {
fixed(HELLO_LEN)?;
let proto_ver = r.u16();
let (fw_major, fw_minor, fw_patch) = (r.u8(), r.u8(), r.u8());
r.skip(1);
Self::Hello(Hello {
proto_ver,
fw_major,
fw_minor,
fw_patch,
board_id: r.u16(),
caps: r.u32(),
uid: r.take(),
board_name: r.take(),
})
}
ty::IMU_BATCH => {
if p.len() < IMU_HEADER_LEN {
return Err(Error::PayloadSize { ty });
}
let t0_ns = r.u64();
let dt_ns = r.u32();
let n = usize::from(r.u8());
if n == 0 || n > IMU_MAX_SAMPLES {
return Err(Error::ImuCount);
}
fixed(IMU_HEADER_LEN + IMU_SAMPLE_LEN * n)?;
let (imu_id, flags) = (r.u8(), r.u8());
r.skip(1);
let seq0 = r.u32();
Self::ImuBatch(ImuBatch {
t0_ns,
dt_ns,
imu_id,
flags,
seq0,
samples: ImuSamples::Raw(r.rest()),
})
}
ty::BARO => {
fixed(BARO_LEN)?;
Self::Baro(Baro {
t_ns: r.u64(),
pressure_pa: r.f32(),
temp_c: r.f32(),
baro_id: r.u8(),
})
}
ty::MAG => {
fixed(MAG_LEN)?;
Self::Mag(Mag {
t_ns: r.u64(),
field_ut: [r.f32(), r.f32(), r.f32()],
mag_id: r.u8(),
})
}
ty::TRIGGER => {
fixed(TRIGGER_LEN)?;
let (seq, cam_mask, flags) = (r.u32(), r.u8(), r.u8());
r.skip(2);
Self::Trigger(Trigger {
seq,
cam_mask,
flags,
t_start_ns: r.u64(),
t_mid_ns: r.u64(),
exposure_ns: r.u32(),
})
}
ty::PPS => {
fixed(PPS_LEN)?;
let (t_ns, locked) = (r.u64(), r.u8());
r.skip(3);
Self::Pps(Pps {
t_ns,
locked,
pps_count: r.u32(),
phase_err_ns: r.i32(),
freq_corr_ppb: r.i32(),
})
}
ty::GNSS_RAW => {
if p.len() < GNSS_HEADER_LEN || p.len() > GNSS_HEADER_LEN + GNSS_MAX_BYTES {
return Err(Error::PayloadSize { ty });
}
let (t_ns, port) = (r.u64(), r.u8());
r.skip(1);
Self::GnssRaw(GnssRaw {
t_ns,
port,
bytes: r.rest(),
})
}
ty::RTCM_IN => {
if p.len() < RTCM_HEADER_LEN {
return Err(Error::PayloadSize { ty });
}
let port = r.u8();
r.skip(1);
Self::RtcmIn(RtcmIn {
port,
bytes: r.rest(),
})
}
ty::CONFIG => {
fixed(CONFIG_LEN)?;
Self::Config(Config {
trigger_hz: r.u16(),
exposure_us: r.u32(),
imu_odr_hz: r.u16(),
cam_mask: r.u8(),
trigger_mode: r.u8(),
pps_out: r.u8(),
gprmc_out: r.u8(),
imu_batch: r.u8(),
heater_target_c: r.i8(),
})
}
ty::HEALTH => {
fixed(HEALTH_LEN)?;
let (t_ns, uptime_s, mcu_temp_c, imu_temp_c, vin_mv) =
(r.u64(), r.u32(), r.i16(), r.i16(), r.u16());
r.skip(2);
Self::Health(Health {
t_ns,
uptime_s,
mcu_temp_c,
imu_temp_c,
vin_mv,
usb_tx_drops: r.u32(),
imu_fifo_overflows: r.u32(),
rx_crc_errors: r.u32(),
trigger_missed: r.u32(),
pps_state: r.u8(),
heater_duty_pct: r.u8(),
})
}
_ => Self::Unknown { ty, payload: p },
})
}
}