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| author | Nick Terrell <terrelln@fb.com> | 2019-07-31 06:40:58 (GMT) |
|---|---|---|
| committer | Nick Terrell <terrelln@fb.com> | 2019-07-31 17:17:26 (GMT) |
| commit | 38c3945de300851757d0dd76182ee28aaf8253a4 (patch) | |
| tree | 3d80f89589db4dc076fcbcad5efb51319bb0c2de | |
| parent | be1738aa46326e86e9c3bb1029abaadce45b8e72 (diff) | |
| download | lz4-38c3945de300851757d0dd76182ee28aaf8253a4.zip lz4-38c3945de300851757d0dd76182ee28aaf8253a4.tar.gz lz4-38c3945de300851757d0dd76182ee28aaf8253a4.tar.bz2 | |
[lz4hc] Only allow chain swapping forwards
When the match is very long and found quickly, we can do
matchLength * nbCompares iterations through the chain
swapping, which can really slow down compression.
| -rw-r--r-- | lib/lz4hc.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/lib/lz4hc.c b/lib/lz4hc.c index 596888a..0608ec6 100644 --- a/lib/lz4hc.c +++ b/lib/lz4hc.c @@ -314,7 +314,7 @@ LZ4HC_InsertAndGetWiderMatch ( if (matchIndex + (U32)longest <= ipIndex) { U32 distanceToNextMatch = 1; int pos; - for (pos = 0; pos <= longest - MINMATCH; ++pos) { + for (pos = matchChainPos; pos <= longest - MINMATCH; ++pos) { U32 const candidateDist = DELTANEXTU16(chainTable, matchIndex + (U32)pos); if (candidateDist > distanceToNextMatch) { distanceToNextMatch = candidateDist; |