Enum CParameter

Variants

TargetCBlockSize(u32)

Target CBlock size.

Tries to make compressed blocks fit in this size (not a guarantee, just a target). Useful to reduce end-to-end latency in low-bandwidth environments.

No target when the value is 0.

CompressionLevel(CompressionLevel)

Compression level to use.

Compression levels are global presets for the other compression parameters.

WindowLog(u32)

Maximum allowed back-reference distance.

The actual distance is 2 power "this value".

HashLog(u32)

ChainLog(u32)

SearchLog(u32)

MinMatch(u32)

TargetLength(u32)

Strategy(Strategy)

EnableLongDistanceMatching(bool)

LdmHashLog(u32)

LdmMinMatch(u32)

LdmBucketSizeLog(u32)

LdmHashRateLog(u32)

ContentSizeFlag(bool)

ChecksumFlag(bool)

DictIdFlag(bool)

NbWorkers(u32)

How many threads will be spawned.

With a default value of 0, compress_stream* functions block until they complete.

With any other value (including 1, a single compressing thread), these methods directly return, and the actual compression is done in the background (until a flush is requested).

Note: this will only work if the zstdmt feature is activated.

JobSize(u32)

Size in bytes of a compression job.

Does not have any effect when NbWorkers is set to 0.

The default value of 0 finds the best job size based on the compression parameters.

Note: this will only work if the zstdmt feature is activated.

OverlapSizeLog(u32)

Specifies how much overlap must be given to each worker.

Possible values:

• 0 (default value): automatic overlap based on compression strategy.
• 1: No overlap
• 1 < n < 9: Overlap a fraction of the window size, defined as 1/(2 ^ 9-n).
• 9: Full overlap (as long as the window)
• 9 < m: Will return an error.

Note: this will only work if the zstdmt feature is activated.