Trait Decoder 

pub trait Decoder {
    // Required methods
    fn decode(
        &mut self,
        input: &[u8],
        output: &mut [u8],
    ) -> Result<(Progress, Status), Error>;
    fn finish(&mut self, output: &mut [u8]) -> Result<(Progress, Status), Error>;
    fn reset(&mut self);
    fn discard_output(
        &mut self,
        input: &[u8],
        n: usize,
    ) -> Result<(Progress, Status), Error>;
}

A streaming decompressor.

Symmetric to Encoder plus an optional discard_output.

Post-error state

After any Err(_) return, the decoder is poisoned: subsequent calls without an intervening reset are unspecified and may return further errors. Some decoders (deflate, zlib, gzip, …) explicitly track a poison flag and return Error::Corrupt until reset.

Required Methods

fn decode( &mut self, input: &[u8], output: &mut [u8], ) -> Result<(Progress, Status), Error>

fn finish(&mut self, output: &mut [u8]) -> Result<(Progress, Status), Error>

fn reset(&mut self)

See Encoder::reset — configuration is preserved.

fn discard_output( &mut self, input: &[u8], n: usize, ) -> Result<(Progress, Status), Error>

Advance the decompressed stream by up to n decompressed bytes without writing them to the caller.

The signature still takes input because the decoder still needs compressed bytes to advance its state; the n parameter just tells the decoder to discard those decompressed bytes rather than emit them. Best-effort: stops at input exhaustion or after exactly n bytes have been discarded, whichever comes first.

Useful when listing files in a .tar.gz without materialising their contents.

The default implementation just runs decode into a small scratch buffer and discards the result; algorithms that can short-circuit (e.g. through stored / uncompressed blocks) are encouraged to override.

Dyn Compatibility

This trait is dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementors

impl<T: RawDecoder> Decoder for T