Struct Decompressor 

pub struct Decompressor<'a> {
    context: DCtx<'a>,
}

Allows to decompress independently multiple blocks of data.

This reduces memory usage compared to calling decompress multiple times.

Fields

context: DCtx<'a>

Implementations

impl Decompressor<'static>

pub fn new() -> Result<Self>

Creates a new zstd decompressor.

pub fn with_dictionary(dictionary: &[u8]) -> Result<Self>

Creates a new zstd decompressor, using the given dictionary.

impl<'a> Decompressor<'a>

pub fn with_prepared_dictionary<'b>( dictionary: &'a DecoderDictionary<'b>, ) -> Result<Self>

where 'b: 'a,

Creates a new decompressor using an existing DecoderDictionary.

Note that using a dictionary means that compression will need to use the same dictionary.

pub fn set_dictionary(&mut self, dictionary: &[u8]) -> Result<()>

Changes the dictionary used by this decompressor.

Will affect future compression jobs.

Note that using a dictionary means that compression will need to use the same dictionary.

pub fn set_prepared_dictionary<'b>( &mut self, dictionary: &'a DecoderDictionary<'b>, ) -> Result<()>

where 'b: 'a,

Changes the dictionary used by this decompressor.

Note that using a dictionary means that compression will need to use the same dictionary.

pub fn decompress_to_buffer<C: WriteBuf + ?Sized>( &mut self, source: &[u8], destination: &mut C, ) -> Result<usize>

Deompress a single block of data to the given destination buffer.

Returns the number of bytes written, or an error if something happened (for instance if the destination buffer was too small). crate::decompressed_size() says how big the result will be, when the frame records it - there is no need to keep the size alongside the data yourself. For a Vec it is the capacity that bounds the output, so reserve what you need rather than resize.

pub fn decompress(&mut self, data: &[u8], capacity: usize) -> Result<Vec<u8>>

Decompress a block of data, and return the result in a Vec<u8>.

The decompressed data should be at most capacity bytes, or an error will be returned.

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

Sets a decompression parameter for this decompressor.

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

Sets the maximum back-reference distance.

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

This will need to at least match the value set when compressing.

pub fn upper_bound(data: &[u8]) -> Option<usize>

Get an upper bound on the decompressed size of data, if available

This can be used to pre-allocate enough capacity for decompress_to_buffer and is used by decompress to ensure that it does not over-allocate if you supply a large capacity.

Returns None if the size cannot be determined, or does not fit a usize. That happens when the frame does not record its decompressed size - which is normal for anything a streaming compressor produced without being told the length up front.

With the experimental feature this sums every frame in data. Without it, the answer is limited to a single frame, since the function that adds them up is part of zstd’s experimental API.

Trait Implementations

impl<'a> Default for Decompressor<'a>

fn default() -> Decompressor<'a>

Returns the “default value” for a type.