Struct FrameEncoder

pub struct FrameEncoder<W: Write> { /* private fields */ }

A writer for compressing a LZ4 stream.

This FrameEncoder wraps any other writer that implements io::Write. Bytes written to this writer are compressed using the LZ4 frame format.

Writes are buffered automatically, so there’s no need to wrap the given writer in a std::io::BufWriter.

To ensure a well formed stream the encoder must be finalized by calling either the finish(), try_finish(), or auto_finish() methods.

Example 1

Serializing json values into a compressed file.

let compressed_file = std::fs::File::create("datafile").unwrap();
let mut compressor = lz4_flex::frame::FrameEncoder::new(compressed_file);
serde_json::to_writer(&mut compressor, &serde_json::json!({ "an": "object" })).unwrap();
compressor.finish().unwrap();

Example 2

Serializing multiple json values into a compressed file using linked blocks.

let compressed_file = std::fs::File::create("datafile").unwrap();
let mut frame_info = lz4_flex::frame::FrameInfo::new();
frame_info.block_mode = lz4_flex::frame::BlockMode::Linked;
let mut compressor = lz4_flex::frame::FrameEncoder::with_frame_info(frame_info, compressed_file);
for i in 0..10u64 {
    serde_json::to_writer(&mut compressor, &serde_json::json!({ "i": i })).unwrap();
}
compressor.finish().unwrap();

Implementations

impl<W: Write> FrameEncoder<W>

pub fn auto_finish(self) -> AutoFinishEncoder<W>

Returns a wrapper around self that will finish the stream on drop.

Note

Errors on drop get silently ignored. If you want to handle errors then use finish() or try_finish() instead.

pub fn with_frame_info(frame_info: FrameInfo, wtr: W) -> Self

Creates a new Encoder with the specified FrameInfo.

pub fn new(wtr: W) -> Self

Creates a new Encoder with the default settings.

pub fn frame_info(&mut self) -> &FrameInfo

The frame information used by this Encoder.

pub fn finish(self) -> Result<W, Error>

Consumes this encoder, flushing internal buffer and writing stream terminator.

pub fn try_finish(&mut self) -> Result<(), Error>

Attempt to finish this output stream, flushing internal buffer and writing stream terminator.

pub fn into_inner(self) -> W

Returns the underlying writer without flushing the stream. This may leave the output in an unfinished state.

pub fn get_ref(&self) -> &W

Gets a reference to the underlying writer in this encoder.

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

Gets a reference to the underlying writer in this encoder.

Note that mutating the output/input state of the stream may corrupt this encoder, so care must be taken when using this method.

Trait Implementations

impl<W: Debug + Write> Debug for FrameEncoder<W>

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

Formats the value using the given formatter.

impl<W: Write> Write for FrameEncoder<W>

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

Writes a buffer into this writer, returning how many bytes were written.

fn flush(&mut self) -> Result<()>

Flushes this output stream, ensuring that all intermediately buffered contents reach their destination.

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

Like write, except that it writes from a slice of buffers.

fn is_write_vectored(&self) -> bool

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

Determines if this Writer has an efficient write_vectored implementation.

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

Attempts to write an entire buffer into this writer.

fn write_all_vectored(&mut self, bufs: &mut [IoSlice<'_>]) -> Result<(), Error>

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

Attempts to write multiple buffers into this writer.

fn write_fmt(&mut self, fmt: Arguments<'_>) -> Result<(), Error>

Writes a formatted string into this writer, returning any error encountered.

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

where Self: Sized,

Creates a “by reference” adapter for this instance of Write.