Commit Graph

11 Commits

Author SHA1 Message Date
Nick Terrell
295ab0dbfa Only load extra table positions for CDicts
Zstdmt uses prefixes to load the overlap between segments. Loading extra
positions makes compression non-deterministic, depending on the previous
job the context was used for. Since loading extra position takes extra
time as well, only do it when creating a `ZSTD_CDict`.

Fixes #1077.
2018-04-02 14:41:30 -07:00
Yann Collet
a146ee04ae added negative compression levels
negative compression level trade compression ratio for more compression speed.
They turn off huffman compression of literals,
and use row 0 as baseline with a stepSize = -cLevel.

added associated test in fuzzer

also added : new advanced parameter ZSTD_p_literalCompression
2018-03-11 05:21:53 -07:00
Nick Terrell
7e5e226cbf Split the window state into substructure 2018-02-26 13:29:57 -08:00
Yann Collet
5188749e1c ensure compression parameters are updated when only compression level is changed 2018-02-02 16:31:20 -08:00
Nick Terrell
887cd4e35e Split ZSTD_CCtx into smaller sub-structures 2018-01-16 11:17:50 -08:00
Nick Terrell
9a211d1f05 Load more dictionary positions into table if empty
If the hash table is empty load positions into the hash table
that we would otherwise skip.

| Level | Data Set     | Improvement |
|-------|--------------|-------------|
| 1     | github       | 0.44%       |
| 1     | hg-changelog | 0.13%       |
| 1     | hg-commands  | 1.28%       |
| 1     | hg-manifest  | 0.70%       |
| 3     | github       | 0.74%       |
| 3     | hg-changelog | 0.87%       |
| 3     | hg-commands  | 1.74%       |
| 3     | hg-manifest  | 0.23%       |
2018-01-12 16:17:22 -08:00
Yann Collet
ee441d5d2b renamed zstd_compress.h into zstd_compress_internal.h
to emphasize the fact that all definitions it contains
must remain private, accross lib/compress modules.
2017-11-07 16:15:23 -08:00
Stella Lau
eb3327c10a Merge branch 'dev' of https://github.com/facebook/zstd into ldm-mergeDev 2017-09-11 15:00:01 -07:00
Yann Collet
3128e03be6 updated license header
to clarify dual-license meaning as "or"
2017-09-08 00:09:23 -07:00
Stella Lau
eeff55dfa8 Merge remote-tracking branch 'upstream/dev' into ldm-mergeDev 2017-09-06 15:56:32 -07:00
Nick Terrell
721726d688 Split parsers out of zstd_compress.c 2017-09-05 17:10:25 -07:00