Trait tokio_core::net::UdpCodec
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[src]
pub trait UdpCodec { type In; type Out; fn decode(&mut self, src: &SocketAddr, buf: &[u8]) -> Result<Self::In>; fn encode(&mut self, msg: Self::Out, buf: &mut Vec<u8>) -> SocketAddr; }
Encoding of frames via buffers.
This trait is used when constructing an instance of UdpFramed
and provides
the In
and Out
types which are decoded and encoded from the socket,
respectively.
Because UDP is a connectionless protocol, the decode
method receives the
address where data came from and the encode
method is also responsible for
determining the remote host to which the datagram should be sent
The trait itself is implemented on a type that can track state for decoding
or encoding, which is particularly useful for streaming parsers. In many
cases, though, this type will simply be a unit struct (e.g. struct HttpCodec
).
Associated Types
Required Methods
fn decode(&mut self, src: &SocketAddr, buf: &[u8]) -> Result<Self::In>
Attempts to decode a frame from the provided buffer of bytes.
This method is called by UdpFramed
on a single datagram which has been
read from a socket. The buf
argument contains the data that was
received from the remote address, and src
is the address the data came
from. Note that typically this method should require the entire contents
of buf
to be valid or otherwise return an error with trailing data.
Finally, if the bytes in the buffer are malformed then an error is
returned indicating why. This informs Framed
that the stream is now
corrupt and should be terminated.
fn encode(&mut self, msg: Self::Out, buf: &mut Vec<u8>) -> SocketAddr
Encodes a frame into the buffer provided.
This method will encode msg
into the byte buffer provided by buf
.
The buf
provided is an internal buffer of the Framed
instance and
will be written out when possible.
The encode method also determines the destination to which the buffer
should be directed, which will be returned as a SocketAddr
.