Struct zstd::stream::read::Encoder

pub struct Encoder<'a, R> { /* private fields */ }

An encoder that compress input data from another Read.

Implementations

impl<R: Read> Encoder<'static, BufReader<R>>

pub fn new(reader: R, level: i32) -> Result<Self>

Creates a new encoder.

impl<R: BufRead> Encoder<'static, R>

pub fn with_buffer(reader: R, level: i32) -> Result<Self>

Creates a new encoder around a BufRead.

pub fn with_dictionary(reader: R, level: i32, dictionary: &[u8]) -> Result<Self>

Creates a new encoder, using an existing dictionary.

The dictionary must be the same as the one used during compression.

impl<'a, R: BufRead> Encoder<'a, R>

pub fn with_prepared_dictionary<'b>( reader: R, dictionary: &EncoderDictionary<'b>, ) -> Result<Self>

where 'b: 'a,

Creates a new encoder, using an existing EncoderDictionary.

The dictionary must be the same as the one used during compression.

pub fn recommended_output_size() -> usize

Recommendation for the size of the output buffer.

pub fn get_ref(&self) -> &R

Acquire a reference to the underlying reader.

pub fn get_mut(&mut self) -> &mut R

Acquire a mutable reference to the underlying reader.

Note that mutation of the reader may result in surprising results if this encoder is continued to be used.

pub fn flush(&mut self, out: &mut [u8]) -> Result<usize>

Flush any internal buffer.

This ensures all input consumed so far is compressed.

Since it prevents bundling currently buffered data with future input, it may affect compression ratio.

• Returns the number of bytes written to out.
• Returns Ok(0) when everything has been flushed.

pub fn finish(self) -> R

Return the inner Read.

Calling finish() is not required after reading a stream - just use it if you need to get the Read back.

pub fn set_parameter(&mut self, parameter: CParameter) -> Result<()>

Sets the given zstd compression parameter.

pub fn set_pledged_src_size(&mut self, size: Option<u64>) -> Result<()>

Sets the expected size of the input.

This affects the compression effectiveness.

It is an error to give an incorrect size (an error will be returned when closing the stream if the size does not match what was pledged).

Giving a None size means the size is unknown (this is the default).

pub fn include_checksum(&mut self, include_checksum: bool) -> Result<()>

Controls whether zstd should include a content checksum at the end of each frame.

pub fn include_dictid(&mut self, include_dictid: bool) -> Result<()>

Enables or disables storing of the dict id.

Defaults to true. If false, the behaviour of decoding with a wrong dictionary is undefined.

pub fn include_contentsize(&mut self, include_contentsize: bool) -> Result<()>

Enables or disabled storing of the contentsize.

Note that this only has an effect if the size is given with set_pledged_src_size.

pub fn long_distance_matching( &mut self, long_distance_matching: bool, ) -> Result<()>

Enables or disables long-distance matching

pub fn set_target_cblock_size(&mut self, target_size: Option<u32>) -> Result<()>

Sets the target size for compressed blocks.

A lower block size may result in slightly lower speed (~2%) and compression ratio (~0.1%), but may decrease end-to-end latency in low-bandwidth environments (time to first decompressed byte).

No value, or a value of zero, results in no contraint for the block sizes.

pub fn window_log(&mut self, log_distance: u32) -> Result<()>

Sets the maximum back-reference distance.

The actual maximum distance is going to be 2^log_distance.

Note that decompression will need to use at least the same setting.

Trait Implementations

impl<R: BufRead> Read for Encoder<'_, R>

fn read(&mut self, buf: &mut [u8]) -> Result<usize>

Pull some bytes from this source into the specified buffer, returning how many bytes were read.

fn read_vectored(&mut self, bufs: &mut [IoSliceMut<'_>]) -> Result<usize, Error>

Like read, except that it reads into a slice of buffers.

fn is_read_vectored(&self) -> bool

🔬This is a nightly-only experimental API. (can_vector)

Determines if this Reader has an efficient read_vectored implementation.

fn read_to_end(&mut self, buf: &mut Vec<u8>) -> Result<usize, Error>

Reads all bytes until EOF in this source, placing them into buf.

fn read_to_string(&mut self, buf: &mut String) -> Result<usize, Error>

Reads all bytes until EOF in this source, appending them to buf.

fn read_exact(&mut self, buf: &mut [u8]) -> Result<(), Error>

Reads the exact number of bytes required to fill buf.

fn read_buf(&mut self, buf: BorrowedCursor<'_>) -> Result<(), Error>

🔬This is a nightly-only experimental API. (read_buf)

Pull some bytes from this source into the specified buffer.

fn read_buf_exact(&mut self, cursor: BorrowedCursor<'_>) -> Result<(), Error>

🔬This is a nightly-only experimental API. (read_buf)

Reads the exact number of bytes required to fill cursor.

fn by_ref(&mut self) -> &mut Self

where Self: Sized,

Creates a “by reference” adaptor for this instance of Read.

fn bytes(self) -> Bytes<Self>

where Self: Sized,

Transforms this Read instance to an Iterator over its bytes.

fn chain<R>(self, next: R) -> Chain<Self, R>

where R: Read, Self: Sized,

Creates an adapter which will chain this stream with another.

fn take(self, limit: u64) -> Take<Self>

where Self: Sized,

Creates an adapter which will read at most limit bytes from it.