[VOL-4291] Rw-core updates for gRPC migration
Change-Id: I8d5a554409115b29318089671ca4e1ab3fa98810
diff --git a/vendor/github.com/pierrec/lz4/block.go b/vendor/github.com/pierrec/lz4/block.go
index 5755cda..664d9be 100644
--- a/vendor/github.com/pierrec/lz4/block.go
+++ b/vendor/github.com/pierrec/lz4/block.go
@@ -2,8 +2,8 @@
import (
"encoding/binary"
- "fmt"
"math/bits"
+ "sync"
)
// blockHash hashes the lower 6 bytes into a value < htSize.
@@ -35,24 +35,31 @@
// CompressBlock compresses the source buffer into the destination one.
// This is the fast version of LZ4 compression and also the default one.
-// The size of hashTable must be at least 64Kb.
//
-// The size of the compressed data is returned. If it is 0 and no error, then the data is incompressible.
+// The argument hashTable is scratch space for a hash table used by the
+// compressor. If provided, it should have length at least 1<<16. If it is
+// shorter (or nil), CompressBlock allocates its own hash table.
+//
+// The size of the compressed data is returned.
+//
+// If the destination buffer size is lower than CompressBlockBound and
+// the compressed size is 0 and no error, then the data is incompressible.
//
// An error is returned if the destination buffer is too small.
-func CompressBlock(src, dst []byte, hashTable []int) (di int, err error) {
+func CompressBlock(src, dst []byte, hashTable []int) (_ int, err error) {
defer recoverBlock(&err)
+ // Return 0, nil only if the destination buffer size is < CompressBlockBound.
+ isNotCompressible := len(dst) < CompressBlockBound(len(src))
+
// adaptSkipLog sets how quickly the compressor begins skipping blocks when data is incompressible.
- // This significantly speeds up incompressible data and usually has very small impact on compresssion.
+ // This significantly speeds up incompressible data and usually has very small impact on compression.
// bytes to skip = 1 + (bytes since last match >> adaptSkipLog)
const adaptSkipLog = 7
- sn, dn := len(src)-mfLimit, len(dst)
- if sn <= 0 || dn == 0 {
- return 0, nil
- }
if len(hashTable) < htSize {
- return 0, fmt.Errorf("hash table too small, should be at least %d in size", htSize)
+ htIface := htPool.Get()
+ defer htPool.Put(htIface)
+ hashTable = (*(htIface).(*[htSize]int))[:]
}
// Prove to the compiler the table has at least htSize elements.
// The compiler can see that "uint32() >> hashShift" cannot be out of bounds.
@@ -60,7 +67,11 @@
// si: Current position of the search.
// anchor: Position of the current literals.
- var si, anchor int
+ var si, di, anchor int
+ sn := len(src) - mfLimit
+ if sn <= 0 {
+ goto lastLiterals
+ }
// Fast scan strategy: the hash table only stores the last 4 bytes sequences.
for si < sn {
@@ -124,7 +135,7 @@
si, mLen = si+mLen, si+minMatch
// Find the longest match by looking by batches of 8 bytes.
- for si < sn {
+ for si+8 < sn {
x := binary.LittleEndian.Uint64(src[si:]) ^ binary.LittleEndian.Uint64(src[si-offset:])
if x == 0 {
si += 8
@@ -184,7 +195,8 @@
hashTable[h] = si - 2
}
- if anchor == 0 {
+lastLiterals:
+ if isNotCompressible && anchor == 0 {
// Incompressible.
return 0, nil
}
@@ -205,7 +217,7 @@
di++
// Write the last literals.
- if di >= anchor {
+ if isNotCompressible && di >= anchor {
// Incompressible.
return 0, nil
}
@@ -213,6 +225,13 @@
return di, nil
}
+// Pool of hash tables for CompressBlock.
+var htPool = sync.Pool{
+ New: func() interface{} {
+ return new([htSize]int)
+ },
+}
+
// blockHash hashes 4 bytes into a value < winSize.
func blockHashHC(x uint32) uint32 {
const hasher uint32 = 2654435761 // Knuth multiplicative hash.
@@ -224,22 +243,24 @@
//
// CompressBlockHC compression ratio is better than CompressBlock but it is also slower.
//
-// The size of the compressed data is returned. If it is 0 and no error, then the data is not compressible.
+// The size of the compressed data is returned.
+//
+// If the destination buffer size is lower than CompressBlockBound and
+// the compressed size is 0 and no error, then the data is incompressible.
//
// An error is returned if the destination buffer is too small.
-func CompressBlockHC(src, dst []byte, depth int) (di int, err error) {
+func CompressBlockHC(src, dst []byte, depth int) (_ int, err error) {
defer recoverBlock(&err)
+ // Return 0, nil only if the destination buffer size is < CompressBlockBound.
+ isNotCompressible := len(dst) < CompressBlockBound(len(src))
+
// adaptSkipLog sets how quickly the compressor begins skipping blocks when data is incompressible.
- // This significantly speeds up incompressible data and usually has very small impact on compresssion.
+ // This significantly speeds up incompressible data and usually has very small impact on compression.
// bytes to skip = 1 + (bytes since last match >> adaptSkipLog)
const adaptSkipLog = 7
- sn, dn := len(src)-mfLimit, len(dst)
- if sn <= 0 || dn == 0 {
- return 0, nil
- }
- var si int
+ var si, di, anchor int
// hashTable: stores the last position found for a given hash
// chainTable: stores previous positions for a given hash
@@ -249,7 +270,11 @@
depth = winSize
}
- anchor := si
+ sn := len(src) - mfLimit
+ if sn <= 0 {
+ goto lastLiterals
+ }
+
for si < sn {
// Hash the next 4 bytes (sequence).
match := binary.LittleEndian.Uint32(src[si:])
@@ -356,12 +381,13 @@
}
}
- if anchor == 0 {
+ if isNotCompressible && anchor == 0 {
// Incompressible.
return 0, nil
}
// Last literals.
+lastLiterals:
lLen := len(src) - anchor
if lLen < 0xF {
dst[di] = byte(lLen << 4)
@@ -378,7 +404,7 @@
di++
// Write the last literals.
- if di >= anchor {
+ if isNotCompressible && di >= anchor {
// Incompressible.
return 0, nil
}