diff options
Diffstat (limited to 'vendor/github.com/klauspost/compress/flate/level6.go')
| -rw-r--r-- | vendor/github.com/klauspost/compress/flate/level6.go | 30 |
1 files changed, 20 insertions, 10 deletions
diff --git a/vendor/github.com/klauspost/compress/flate/level6.go b/vendor/github.com/klauspost/compress/flate/level6.go index 62888edf3..f1e9d98fa 100644 --- a/vendor/github.com/klauspost/compress/flate/level6.go +++ b/vendor/github.com/klauspost/compress/flate/level6.go @@ -12,6 +12,7 @@ func (e *fastEncL6) Encode(dst *tokens, src []byte) { const ( inputMargin = 12 - 1 minNonLiteralBlockSize = 1 + 1 + inputMargin + hashShortBytes = 4 ) if debugDeflate && e.cur < 0 { panic(fmt.Sprint("e.cur < 0: ", e.cur)) @@ -90,7 +91,7 @@ func (e *fastEncL6) Encode(dst *tokens, src []byte) { var l int32 var t int32 for { - nextHashS := hash4x64(cv, tableBits) + nextHashS := hashLen(cv, tableBits, hashShortBytes) nextHashL := hash7(cv, tableBits) s = nextS nextS = s + doEvery + (s-nextEmit)>>skipLog @@ -107,7 +108,7 @@ func (e *fastEncL6) Encode(dst *tokens, src []byte) { eLong.Cur, eLong.Prev = entry, eLong.Cur // Calculate hashes of 'next' - nextHashS = hash4x64(next, tableBits) + nextHashS = hashLen(next, tableBits, hashShortBytes) nextHashL = hash7(next, tableBits) t = lCandidate.Cur.offset - e.cur @@ -213,24 +214,33 @@ func (e *fastEncL6) Encode(dst *tokens, src []byte) { // Try to locate a better match by checking the end-of-match... if sAt := s + l; sAt < sLimit { + // Allow some bytes at the beginning to mismatch. + // Sweet spot is 2/3 bytes depending on input. + // 3 is only a little better when it is but sometimes a lot worse. + // The skipped bytes are tested in Extend backwards, + // and still picked up as part of the match if they do. + const skipBeginning = 2 eLong := &e.bTable[hash7(load6432(src, sAt), tableBits)] // Test current - t2 := eLong.Cur.offset - e.cur - l - off := s - t2 + t2 := eLong.Cur.offset - e.cur - l + skipBeginning + s2 := s + skipBeginning + off := s2 - t2 if off < maxMatchOffset { if off > 0 && t2 >= 0 { - if l2 := e.matchlenLong(s, t2, src); l2 > l { + if l2 := e.matchlenLong(s2, t2, src); l2 > l { t = t2 l = l2 + s = s2 } } // Test next: - t2 = eLong.Prev.offset - e.cur - l - off := s - t2 + t2 = eLong.Prev.offset - e.cur - l + skipBeginning + off := s2 - t2 if off > 0 && off < maxMatchOffset && t2 >= 0 { - if l2 := e.matchlenLong(s, t2, src); l2 > l { + if l2 := e.matchlenLong(s2, t2, src); l2 > l { t = t2 l = l2 + s = s2 } } } @@ -277,7 +287,7 @@ func (e *fastEncL6) Encode(dst *tokens, src []byte) { // Index after match end. for i := nextS + 1; i < int32(len(src))-8; i += 2 { cv := load6432(src, i) - e.table[hash4x64(cv, tableBits)] = tableEntry{offset: i + e.cur} + e.table[hashLen(cv, tableBits, hashShortBytes)] = tableEntry{offset: i + e.cur} eLong := &e.bTable[hash7(cv, tableBits)] eLong.Cur, eLong.Prev = tableEntry{offset: i + e.cur}, eLong.Cur } @@ -292,7 +302,7 @@ func (e *fastEncL6) Encode(dst *tokens, src []byte) { t2 := tableEntry{offset: t.offset + 1} eLong := &e.bTable[hash7(cv, tableBits)] eLong2 := &e.bTable[hash7(cv>>8, tableBits)] - e.table[hash4x64(cv, tableBits)] = t + e.table[hashLen(cv, tableBits, hashShortBytes)] = t eLong.Cur, eLong.Prev = t, eLong.Cur eLong2.Cur, eLong2.Prev = t2, eLong2.Cur } |