tpkt 0.1.0

tpkt protocols
Documentation 
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mod error;
mod packet;

use bytes::{Buf, BufMut, BytesMut};

pub use error::*;
pub use packet::TpktFrame;
use tokio_util::codec::{Decoder, Encoder};

pub struct TpktEncoder<E>(pub E);
pub struct TpktDecoder<D>(pub D);

impl<F, E: Encoder<F>> Encoder<TpktFrame<F>> for TpktEncoder<E>
where
    <E as Encoder<F>>::Error: ToTpktError + Send + Sync + 'static,
{
    type Error = Error;

    fn encode(&mut self, item: TpktFrame<F>, dst: &mut BytesMut) -> Result<(), Self::Error> {
        let mut payload = BytesMut::new();
        self.0.encode(item.payload, &mut payload)?;
        let length = payload.len() as u16 + 4;
        dst.put_u8(item.version);
        dst.put_u8(0);
        dst.put_u16(length);
        dst.extend_from_slice(payload.as_ref());
        Ok(())
    }
}

impl<F, D: Decoder<Item = F>> Decoder for TpktDecoder<D>
where
    <D as Decoder>::Error: ToTpktError + Send + Sync + 'static,
{
    type Item = TpktFrame<F>;
    type Error = Error;

    fn decode(&mut self, src: &mut BytesMut) -> Result<Option<Self::Item>, Self::Error> {
        if src.len() < 4 {
            return Ok(None);
        }
        let (Some(index_0), Some(index_1)) = (src.get(2), src.get(3)) else {
            unreachable!()
        };
        let length = u16::from_be_bytes([*index_0, *index_1]);
        let lenght_usize = length as usize;
        if src.len() < lenght_usize {
            return Ok(None);
        }
        let mut framed_datas = src.split_to(lenght_usize);
        let version = framed_datas.get_u8();
        let _reserved = framed_datas.get_u8();
        let _ = framed_datas.get_u16();
        let Some(payload) = self.0.decode(&mut framed_datas)? else {
            // maybe return none
            return Err(Error::Error("payload decode fail!".to_string()));
        };
        Ok(Some(TpktFrame { version, payload }))
    }
}

impl<E: Default> Default for TpktEncoder<E> {
    fn default() -> Self {
        Self(E::default())
    }
}

impl<D: Default> Default for TpktDecoder<D> {
    fn default() -> Self {
        Self(D::default())
    }
}