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authorAshley Cui <acui@redhat.com>2022-02-28 16:23:19 -0500
committerAshley Cui <acui@redhat.com>2022-02-28 16:23:26 -0500
commit569319d3970c2e94e4c6586d4bb17e5cfc108fdf (patch)
tree843f87290ef42f8eee7e9d5963fa916a3172e4ea /vendor/github.com/klauspost/compress/flate/level3.go
parent2225c65f74b3358d810183558185a6344ef686ac (diff)
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Vendor in containers/common@main
Signed-off-by: Ashley Cui <acui@redhat.com>
Diffstat (limited to 'vendor/github.com/klauspost/compress/flate/level3.go')
-rw-r--r--vendor/github.com/klauspost/compress/flate/level3.go45
1 files changed, 24 insertions, 21 deletions
diff --git a/vendor/github.com/klauspost/compress/flate/level3.go b/vendor/github.com/klauspost/compress/flate/level3.go
index c22b4244a..465b5e0ba 100644
--- a/vendor/github.com/klauspost/compress/flate/level3.go
+++ b/vendor/github.com/klauspost/compress/flate/level3.go
@@ -5,7 +5,7 @@ import "fmt"
// fastEncL3
type fastEncL3 struct {
fastGen
- table [tableSize]tableEntryPrev
+ table [1 << 16]tableEntryPrev
}
// Encode uses a similar algorithm to level 2, will check up to two candidates.
@@ -13,6 +13,8 @@ func (e *fastEncL3) Encode(dst *tokens, src []byte) {
const (
inputMargin = 8 - 1
minNonLiteralBlockSize = 1 + 1 + inputMargin
+ tableBits = 16
+ tableSize = 1 << tableBits
)
if debugDeflate && e.cur < 0 {
@@ -73,7 +75,7 @@ func (e *fastEncL3) Encode(dst *tokens, src []byte) {
nextS := s
var candidate tableEntry
for {
- nextHash := hash(cv)
+ nextHash := hash4u(cv, tableBits)
s = nextS
nextS = s + 1 + (s-nextEmit)>>skipLog
if nextS > sLimit {
@@ -156,7 +158,7 @@ func (e *fastEncL3) Encode(dst *tokens, src []byte) {
// Index first pair after match end.
if int(t+4) < len(src) && t > 0 {
cv := load3232(src, t)
- nextHash := hash(cv)
+ nextHash := hash4u(cv, tableBits)
e.table[nextHash] = tableEntryPrev{
Prev: e.table[nextHash].Cur,
Cur: tableEntry{offset: e.cur + t},
@@ -165,30 +167,31 @@ func (e *fastEncL3) Encode(dst *tokens, src []byte) {
goto emitRemainder
}
- // We could immediately start working at s now, but to improve
- // compression we first update the hash table at s-3 to s.
- x := load6432(src, s-3)
- prevHash := hash(uint32(x))
- e.table[prevHash] = tableEntryPrev{
- Prev: e.table[prevHash].Cur,
- Cur: tableEntry{offset: e.cur + s - 3},
+ // Store every 5th hash in-between.
+ for i := s - l + 2; i < s-5; i += 5 {
+ nextHash := hash4u(load3232(src, i), tableBits)
+ e.table[nextHash] = tableEntryPrev{
+ Prev: e.table[nextHash].Cur,
+ Cur: tableEntry{offset: e.cur + i}}
}
- x >>= 8
- prevHash = hash(uint32(x))
+ // We could immediately start working at s now, but to improve
+ // compression we first update the hash table at s-2 to s.
+ x := load6432(src, s-2)
+ prevHash := hash4u(uint32(x), tableBits)
e.table[prevHash] = tableEntryPrev{
Prev: e.table[prevHash].Cur,
Cur: tableEntry{offset: e.cur + s - 2},
}
x >>= 8
- prevHash = hash(uint32(x))
+ prevHash = hash4u(uint32(x), tableBits)
e.table[prevHash] = tableEntryPrev{
Prev: e.table[prevHash].Cur,
Cur: tableEntry{offset: e.cur + s - 1},
}
x >>= 8
- currHash := hash(uint32(x))
+ currHash := hash4u(uint32(x), tableBits)
candidates := e.table[currHash]
cv = uint32(x)
e.table[currHash] = tableEntryPrev{
@@ -200,15 +203,15 @@ func (e *fastEncL3) Encode(dst *tokens, src []byte) {
candidate = candidates.Cur
minOffset := e.cur + s - (maxMatchOffset - 4)
- if candidate.offset > minOffset && cv != load3232(src, candidate.offset-e.cur) {
- // We only check if value mismatches.
- // Offset will always be invalid in other cases.
+ if candidate.offset > minOffset {
+ if cv == load3232(src, candidate.offset-e.cur) {
+ // Found a match...
+ continue
+ }
candidate = candidates.Prev
if candidate.offset > minOffset && cv == load3232(src, candidate.offset-e.cur) {
- offset := s - (candidate.offset - e.cur)
- if offset <= maxMatchOffset {
- continue
- }
+ // Match at prev...
+ continue
}
}
cv = uint32(x >> 8)