Struct Codec 

pub struct Codec { /* private fields */ }

Reusable codec state for one worker.

Two things live here that must not be rebuilt per chunk:

• zstd contexts. A CCtx owns the match tables — megabytes at level 3. The convenience zstd::bulk::compress_to_buffer allocates and frees one on every call, which on 1 MiB chunks costs more than the compression itself.
• A scratch buffer. zstd needs a destination sized to its worst case. Growing a Vec for that means zeroing ~1 MiB per chunk that the codec is about to overwrite anyway. One long-lived buffer pays that once.

Implementations

impl Codec

pub fn new() -> Self

pub fn compress_into( &mut self, cfg: &CompressionConfig, hint: FileHint, input: &[u8], out: &mut Vec<u8>, ) -> Result<Encoded>

Compress input, appending the result to out.

Returns the algorithm actually used, which may be None even when a codec was requested: if the result did not beat min_gain, the raw bytes are written instead. The caller must record the returned algorithm on the wire.

pub fn compress_in_place( &mut self, cfg: &CompressionConfig, hint: FileHint, buf: &mut Vec<u8>, prefix: usize, ) -> Result<Encoded>

Compress the payload already sitting in buf after prefix header bytes.

The sender reads each chunk straight into its frame buffer, so the common case — a chunk that will not be compressed, which is every chunk of a .flac or .mp4 — costs zero copies. Only a chunk that actually wins pays one, and then only of its compressed size.

pub fn decompress_into( &mut self, algo: Algorithm, raw_len: usize, input: &[u8], out: &mut Vec<u8>, ) -> Result<()>

Decompress one chunk. raw_len comes from the frame header and is validated against the decoded length, so a lying sender cannot make us over-allocate beyond the frame limit the caller already enforced.

Trait Implementations

impl Default for Codec

fn default() -> Self

Returns the “default value” for a type.