statime-wire 0.1.1

Full-featured implementation of NTP with NTS support
Documentation 
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use crate::{
    Error,
    common::{ClockIdentity, ClockQuality, TimeSource, Timestamp},
};

/// The body of an announce message
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub struct AnnounceMessage {
    /// Timestamp this announce was generated on the remote.
    pub origin_timestamp: Timestamp,
    /// Current offset between UTC and TAI.
    pub current_utc_offset: i16,
    /// Grandmaster priority 1 as used in the BMCA.
    pub grandmaster_priority_1: u8,
    /// Quality of the grandmaster clock.
    pub grandmaster_clock_quality: ClockQuality,
    /// Grandmaster priority 2 as used in the BMCA.
    pub grandmaster_priority_2: u8,
    /// Identity of the Grandmaster clock
    pub grandmaster_identity: ClockIdentity,
    /// Number of steps in the synchronization graph between sender
    /// of the announce message and the Grandmaster clock.
    pub steps_removed: u16,
    /// Type of time source used by the grandmaster clock.
    pub time_source: TimeSource,
}

impl AnnounceMessage {
    pub(crate) fn content_size(&self) -> usize {
        30
    }

    pub(crate) fn serialize_content(&self, buffer: &mut [u8]) -> Result<(), Error> {
        if buffer.len() < 30 {
            return Err(Error::BufferTooShort);
        }

        self.origin_timestamp.serialize(&mut buffer[0..10])?;
        buffer[10..12].copy_from_slice(&self.current_utc_offset.to_be_bytes());
        buffer[13] = self.grandmaster_priority_1;
        self.grandmaster_clock_quality
            .serialize(&mut buffer[14..18])?;
        buffer[18] = self.grandmaster_priority_2;
        self.grandmaster_identity.serialize(&mut buffer[19..27])?;
        buffer[27..29].copy_from_slice(&self.steps_removed.to_be_bytes());
        buffer[29] = self.time_source.to_primitive();

        Ok(())
    }

    pub(crate) fn deserialize_content(buffer: &[u8]) -> Result<Self, Error> {
        if buffer.len() < 30 {
            return Err(Error::BufferTooShort);
        }

        Ok(Self {
            origin_timestamp: Timestamp::deserialize(&buffer[0..10])?,
            current_utc_offset: i16::from_be_bytes(buffer[10..12].try_into().unwrap()),
            grandmaster_priority_1: buffer[13],
            grandmaster_clock_quality: ClockQuality::deserialize(&buffer[14..18])?,
            grandmaster_priority_2: buffer[18],
            grandmaster_identity: ClockIdentity::deserialize(&buffer[19..27])?,
            steps_removed: u16::from_be_bytes(buffer[27..29].try_into().unwrap()),
            time_source: TimeSource::from_primitive(buffer[29]),
        })
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::common::ClockAccuracy;

    #[test]
    fn announce_wireformat() {
        let representations = [(
            [
                0x00, 0x00, 0x45, 0xb1, 0x11, 0x5a, 0x0a, 0x73, 0x46, 0x60, 0x00, 0x00, 0x00, 0x60,
                0x00, 0x00, 0x00, 0x80, 0x63, 0xff, 0xff, 0x00, 0x09, 0xba, 0xf8, 0x21, 0x00, 0x00,
                0x80, 0x80,
            ],
            AnnounceMessage {
                origin_timestamp: Timestamp::new(1_169_232_218, 175_326_816).unwrap(),
                current_utc_offset: 0,
                grandmaster_priority_1: 96,
                grandmaster_clock_quality: ClockQuality {
                    clock_class: 0,
                    clock_accuracy: ClockAccuracy::Reserved,
                    offset_scaled_log_variance: 128,
                },
                grandmaster_priority_2: 99,
                grandmaster_identity: ClockIdentity([
                    0xff, 0xff, 0x00, 0x09, 0xba, 0xf8, 0x21, 0x00,
                ]),
                steps_removed: 128,
                time_source: TimeSource::Reserved(0x80),
            },
        )];

        for (byte_representation, object_representation) in representations {
            // Test the serialization output
            let mut serialization_buffer = [0; 30];
            object_representation
                .serialize_content(&mut serialization_buffer)
                .unwrap();
            assert_eq!(serialization_buffer, byte_representation);

            // Test the deserialization output
            let deserialized_data =
                AnnounceMessage::deserialize_content(&byte_representation).unwrap();
            assert_eq!(deserialized_data, object_representation);
        }
    }
}