mqtt_codec_kit/common/variable_header/
packet_identifier.rs

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use std::io::{self, Read, Write};

use byteorder::{BigEndian, ReadBytesExt, WriteBytesExt};

use crate::common::{Decodable, Encodable};

/// Packet identifier
#[derive(Debug, Eq, PartialEq, Copy, Clone)]
pub struct PacketIdentifier(pub u16);

impl Encodable for PacketIdentifier {
    fn encode<W: Write>(&self, writer: &mut W) -> Result<(), io::Error> {
        writer.write_u16::<BigEndian>(self.0)
    }

    fn encoded_length(&self) -> u32 {
        2
    }
}

impl Decodable for PacketIdentifier {
    type Error = io::Error;
    type Cond = ();

    fn decode_with<R: Read>(reader: &mut R, _rest: ()) -> Result<PacketIdentifier, io::Error> {
        reader
            .read_u16::<BigEndian>()
            .map(PacketIdentifier)
            .map_err(From::from)
    }
}