Struct EncoderPositionTracker

pub struct EncoderPositionTracker<Enc> { /* private fields */ }

An Encoder wrapper that handles partial writes.

This wrapper internally tracks the position of encoded bytes which makes handling of partial writes very easy. It also simplifies handling of the end.

Implementations

impl<Enc: Encoder> EncoderPositionTracker<Enc>

pub fn encoded_chunk(&self) -> &[u8]

Returns an unprocessed chunk of encoded data.

The returned bytes should be processed - e.g. by writing them into a writer. Empty returned value indicates there are no more bytes.

pub fn consume(&mut self, amount: usize)

Marks the amount of bytes as processed.

The consumer should call this method after (partially) processing the chunk. Usually this is called after successful write or analogous function. The buffer returned by encoded_chunk will by advanced by amount bytes and, if it reached the end, the underlying encoder will be advanced to give the next chunk.

Calling this method with amount larger than encoded_chunk().len() will corrupt the encoder and lead to a panic later. In debug builds this will panic instantly.

pub fn write_once<W: Write>(&mut self, writer: &mut W) -> Result<usize>

Available on crate feature std only.

Issues single write to te writer and advances the position accordingly.

This can be used as a building block for various abstractions or protocols. Returns the number of bytes written. Zero indicates the end of encoding.

pub fn write_all<W: Write>(&mut self, writer: &mut W) -> Result<()>

Available on crate feature std only.

Writes all bytes to the writer until the end or an error.

This is similar to Encoder::write_all with one significant difference: it leaves the state around so the operation can be restarted. This can be used to handle ErrorKind::Interrupted errors which are generally recoverable but users may still wish to act on them (e.g. check a global flag set by a signal).

Trait Implementations

impl<Enc: Clone> Clone for EncoderPositionTracker<Enc>

fn clone(&self) -> EncoderPositionTracker<Enc>

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<Enc: Debug> Debug for EncoderPositionTracker<Enc>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.