Struct zstd_safe::DCtx

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pub struct DCtx<'a>(/* private fields */);

Expand description

A Decompression Context.

The lifetime references the potential dictionary used for this context.

If no dictionary was used, it will most likely be 'static.

Same as DStream.

Implementations§

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impl<'a> DCtx<'a>

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pub fn try_create() -> Option<Self>

Try to create a new decompression context.

Returns None if the operation failed (for example, not enough memory).

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pub fn create() -> Self

Creates a new decoding context.

§Panics

If the context creation fails.

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pub fn decompress<C: WriteBuf + ?Sized>( &mut self, dst: &mut C, src: &[u8], ) -> SafeResult

Fully decompress the given frame.

This decompress an entire frame in-memory. If you can have enough memory to store both the input and output buffer, then it may be faster that streaming decompression.

Wraps the ZSTD_decompressDCtx() function.

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pub fn decompress_using_dict<C: WriteBuf + ?Sized>( &mut self, dst: &mut C, src: &[u8], dict: &[u8], ) -> SafeResult

Fully decompress the given frame using a dictionary.

Dictionary must be identical to the one used during compression.

If you plan on using the same dictionary multiple times, it is faster to create a DDict first and use decompress_using_ddict.

Wraps ZSTD_decompress_usingDict

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pub fn decompress_using_ddict<C: WriteBuf + ?Sized>( &mut self, dst: &mut C, src: &[u8], ddict: &DDict<'_>, ) -> SafeResult

Fully decompress the given frame using a dictionary.

Dictionary must be identical to the one used during compression.

Wraps the ZSTD_decompress_usingDDict() function.

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pub fn init(&mut self) -> SafeResult

Initializes an existing DStream for decompression.

This is equivalent to calling:

reset(SessionOnly)
disable_dictionary()

Wraps the ZSTD_initCStream() function.

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pub fn reset(&mut self, reset: ResetDirective) -> SafeResult

Resets the state of the context.

Depending on the reset mode, it can reset the session, the parameters, or both.

Wraps the ZSTD_DCtx_reset() function.

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pub fn load_dictionary(&mut self, dict: &[u8]) -> SafeResult

Loads a dictionary.

This will let this context decompress frames that were compressed using this dictionary.

The dictionary content will be copied internally and does not need to be kept alive after calling this function.

If you need to use the same dictionary for multiple contexts, it may be more efficient to create a DDict first, then loads that.

The dictionary will apply to all future frames, until a new dictionary is set.

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pub fn disable_dictionary(&mut self) -> SafeResult

Return to “no-dictionary” mode.

This will disable any dictionary/prefix previously registered for future frames.

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pub fn ref_ddict<'b>(&mut self, ddict: &DDict<'b>) -> SafeResult
where 'b: 'a,

References a dictionary.

This will let this context decompress frames compressed with the same dictionary.

It will apply to all frames decompressed by this context (until a new dictionary is set).

Wraps the ZSTD_DCtx_refDDict() function.

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pub fn ref_prefix<'b>(&mut self, prefix: &'b [u8]) -> SafeResult
where 'b: 'a,

Use some prefix as single-use dictionary for the next frame.

Just like a dictionary, this only works if compression was done with the same prefix.

But unlike a dictionary, this only applies to the next frame.

Wraps the ZSTD_DCtx_refPrefix() function.

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pub fn set_parameter(&mut self, param: DParameter) -> SafeResult

Sets a decompression parameter.

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pub fn decompress_stream<C: WriteBuf + ?Sized>( &mut self, output: &mut OutBuffer<'_, C>, input: &mut InBuffer<'_>, ) -> SafeResult

Performs a step of a streaming decompression operation.

This will read some data from input and/or write some data to output.

§Returns

Ok(0) if the current frame just finished decompressing successfully.
Ok(hint) with a hint for the “ideal” amount of input data to provide in the next call. Can be safely ignored.

Wraps the ZSTD_decompressStream() function.

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