Trait bcder::decode::Source

source · 
pub trait Source {
    type Err: From<Error>;

    fn request(&mut self, len: usize) -> Result<usize, Self::Err>;
    fn advance(&mut self, len: usize) -> Result<(), Self::Err>;
    fn slice(&self) -> &[u8] ⓘ;
    fn bytes(&self, start: usize, end: usize) -> Bytes;

    fn take_u8(&mut self) -> Result<u8, Self::Err> { ... }
    fn take_opt_u8(&mut self) -> Result<Option<u8>, Self::Err> { ... }
}
Expand description

A view into a sequence of octets.

Sources form that foundation of decoding. They provide the raw octets to decoders.

A source can only progress forward over time. It provides the ability to access the next few bytes as a slice, advance forward, or advance forward returning a Bytes value of the data it advanced over.

Please note: This trait may change as we gain more experience with decoding in different circumstances. If you implement it for your own types, we would appreciate feedback what worked well and what didn’t.

Required Associated Types§

The error produced by the source.

The type used here needs to wrap ber::decode::Error and extends it by whatever happens if acquiring additional data fails. If Source is implemented for types where this acqusition cannot fail, ber::decode::Error should be used here.

Required Methods§

Request at least len bytes to be available.

The method returns the number of bytes that are actually available. This may only be smaller than len if the source ends with less bytes available.

The method should only return an error if the source somehow fails to get more data such as an IO error or reset connection.

Advance the source by len bytes.

The method advances the start of the view provided by the source by len bytes. Advancing beyond the end of a source is an error. Implementations should return their equivalient of Error::Malformed.

The value of len may be larger than the last length previously request via request.

Returns a bytes slice with the available data.

The slice will be at least as long as the value returned by the last successful request call. It may be longer if more data is available.

Produces a Bytes value from part of the data.

The method returns a Bytes value of the range start..end from the beginning of the current view of the source. Both indexes must not be greater than the value returned by the last successful call to request.

Panics

The method panics if start or end are larger than the last successful call to request.

Provided Methods§

Takes a single octet from the source.

If there aren’t any more octets available from the source, returns a malformed error.

Takes an optional octet from the source.

If there aren’t any more octets available from the source, returns Ok(None).

Implementations on Foreign Types§

Implementors§