Bump github.com/containers/storage from 1.16.3 to 1.16.5

Bumps [github.com/containers/storage](https://github.com/containers/storage) from 1.16.3 to 1.16.5.
- [Release notes](https://github.com/containers/storage/releases)
- [Changelog](https://github.com/containers/storage/blob/master/docs/containers-storage-changes.md)
- [Commits](https://github.com/containers/storage/compare/v1.16.3...v1.16.5)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>
Signed-off-by: Valentin Rothberg <rothberg@redhat.com>

vendor/github.com/klauspost/compress/zstd/decoder.go

@@ -66,7 +66,7 @@ var (
 // A Decoder can be used in two modes:
 //
 // 1) As a stream, or
-// 2) For stateless decoding using DecodeAll or DecodeBuffer.
+// 2) For stateless decoding using DecodeAll.
 //
 // Only a single stream can be decoded concurrently, but the same decoder
 // can run multiple concurrent stateless decodes. It is even possible to

vendor/github.com/klauspost/compress/zstd/enc_better.go

@@ -0,0 +1,521 @@
+// Copyright 2019+ Klaus Post. All rights reserved.
+// License information can be found in the LICENSE file.
+// Based on work by Yann Collet, released under BSD License.
+
+package zstd
+
+import "fmt"
+
+const (
+	betterLongTableBits = 19                       // Bits used in the long match table
+	betterLongTableSize = 1 << betterLongTableBits // Size of the table
+
+	// Note: Increasing the short table bits or making the hash shorter
+	// can actually lead to compression degradation since it will 'steal' more from the
+	// long match table and match offsets are quite big.
+	// This greatly depends on the type of input.
+	betterShortTableBits = 13                        // Bits used in the short match table
+	betterShortTableSize = 1 << betterShortTableBits // Size of the table
+)
+
+type prevEntry struct {
+	offset int32
+	prev   int32
+}
+
+// betterFastEncoder uses 2 tables, one for short matches (5 bytes) and one for long matches.
+// The long match table contains the previous entry with the same hash,
+// effectively making it a "chain" of length 2.
+// When we find a long match we choose between the two values and select the longest.
+// When we find a short match, after checking the long, we check if we can find a long at n+1
+// and that it is longer (lazy matching).
+type betterFastEncoder struct {
+	fastBase
+	table     [betterShortTableSize]tableEntry
+	longTable [betterLongTableSize]prevEntry
+}
+
+// Encode improves compression...
+func (e *betterFastEncoder) Encode(blk *blockEnc, src []byte) {
+	const (
+		// Input margin is the number of bytes we read (8)
+		// and the maximum we will read ahead (2)
+		inputMargin            = 8 + 2
+		minNonLiteralBlockSize = 16
+	)
+
+	// Protect against e.cur wraparound.
+	for e.cur >= bufferReset {
+		if len(e.hist) == 0 {
+			for i := range e.table[:] {
+				e.table[i] = tableEntry{}
+			}
+			for i := range e.longTable[:] {
+				e.longTable[i] = prevEntry{}
+			}
+			e.cur = e.maxMatchOff
+			break
+		}
+		// Shift down everything in the table that isn't already too far away.
+		minOff := e.cur + int32(len(e.hist)) - e.maxMatchOff
+		for i := range e.table[:] {
+			v := e.table[i].offset
+			if v < minOff {
+				v = 0
+			} else {
+				v = v - e.cur + e.maxMatchOff
+			}
+			e.table[i].offset = v
+		}
+		for i := range e.longTable[:] {
+			v := e.longTable[i].offset
+			v2 := e.longTable[i].prev
+			if v < minOff {
+				v = 0
+				v2 = 0
+			} else {
+				v = v - e.cur + e.maxMatchOff
+				if v2 < minOff {
+					v2 = 0
+				} else {
+					v2 = v2 - e.cur + e.maxMatchOff
+				}
+			}
+			e.longTable[i] = prevEntry{
+				offset: v,
+				prev:   v2,
+			}
+		}
+		e.cur = e.maxMatchOff
+		break
+	}
+
+	s := e.addBlock(src)
+	blk.size = len(src)
+	if len(src) < minNonLiteralBlockSize {
+		blk.extraLits = len(src)
+		blk.literals = blk.literals[:len(src)]
+		copy(blk.literals, src)
+		return
+	}
+
+	// Override src
+	src = e.hist
+	sLimit := int32(len(src)) - inputMargin
+	// stepSize is the number of bytes to skip on every main loop iteration.
+	// It should be >= 1.
+	stepSize := int32(e.o.targetLength)
+	if stepSize == 0 {
+		stepSize++
+	}
+
+	const kSearchStrength = 9
+
+	// nextEmit is where in src the next emitLiteral should start from.
+	nextEmit := s
+	cv := load6432(src, s)
+
+	// Relative offsets
+	offset1 := int32(blk.recentOffsets[0])
+	offset2 := int32(blk.recentOffsets[1])
+
+	addLiterals := func(s *seq, until int32) {
+		if until == nextEmit {
+			return
+		}
+		blk.literals = append(blk.literals, src[nextEmit:until]...)
+		s.litLen = uint32(until - nextEmit)
+	}
+	if debug {
+		println("recent offsets:", blk.recentOffsets)
+	}
+
+encodeLoop:
+	for {
+		var t int32
+		// We allow the encoder to optionally turn off repeat offsets across blocks
+		canRepeat := len(blk.sequences) > 2
+		var matched int32
+
+		for {
+			if debugAsserts && canRepeat && offset1 == 0 {
+				panic("offset0 was 0")
+			}
+
+			nextHashS := hash5(cv, betterShortTableBits)
+			nextHashL := hash8(cv, betterLongTableBits)
+			candidateL := e.longTable[nextHashL]
+			candidateS := e.table[nextHashS]
+
+			const repOff = 1
+			repIndex := s - offset1 + repOff
+			off := s + e.cur
+			e.longTable[nextHashL] = prevEntry{offset: off, prev: candidateL.offset}
+			e.table[nextHashS] = tableEntry{offset: off, val: uint32(cv)}
+
+			if canRepeat {
+				if repIndex >= 0 && load3232(src, repIndex) == uint32(cv>>(repOff*8)) {
+					// Consider history as well.
+					var seq seq
+					lenght := 4 + e.matchlen(s+4+repOff, repIndex+4, src)
+
+					seq.matchLen = uint32(lenght - zstdMinMatch)
+
+					// We might be able to match backwards.
+					// Extend as long as we can.
+					start := s + repOff
+					// We end the search early, so we don't risk 0 literals
+					// and have to do special offset treatment.
+					startLimit := nextEmit + 1
+
+					tMin := s - e.maxMatchOff
+					if tMin < 0 {
+						tMin = 0
+					}
+					for repIndex > tMin && start > startLimit && src[repIndex-1] == src[start-1] && seq.matchLen < maxMatchLength-zstdMinMatch-1 {
+						repIndex--
+						start--
+						seq.matchLen++
+					}
+					addLiterals(&seq, start)
+
+					// rep 0
+					seq.offset = 1
+					if debugSequences {
+						println("repeat sequence", seq, "next s:", s)
+					}
+					blk.sequences = append(blk.sequences, seq)
+
+					// Index match start+1 (long) -> s - 1
+					index0 := s + repOff
+					s += lenght + repOff
+
+					nextEmit = s
+					if s >= sLimit {
+						if debug {
+							println("repeat ended", s, lenght)
+
+						}
+						break encodeLoop
+					}
+					// Index skipped...
+					for index0 < s-1 {
+						cv0 := load6432(src, index0)
+						cv1 := cv0 >> 8
+						h0 := hash8(cv0, betterLongTableBits)
+						off := index0 + e.cur
+						e.longTable[h0] = prevEntry{offset: off, prev: e.longTable[h0].offset}
+						e.table[hash5(cv1, betterShortTableBits)] = tableEntry{offset: off + 1, val: uint32(cv1)}
+						index0 += 2
+					}
+					cv = load6432(src, s)
+					continue
+				}
+				const repOff2 = 1
+
+				// We deviate from the reference encoder and also check offset 2.
+				// Still slower and not much better, so disabled.
+				// repIndex = s - offset2 + repOff2
+				if false && repIndex >= 0 && load6432(src, repIndex) == load6432(src, s+repOff) {
+					// Consider history as well.
+					var seq seq
+					lenght := 8 + e.matchlen(s+8+repOff2, repIndex+8, src)
+
+					seq.matchLen = uint32(lenght - zstdMinMatch)
+
+					// We might be able to match backwards.
+					// Extend as long as we can.
+					start := s + repOff2
+					// We end the search early, so we don't risk 0 literals
+					// and have to do special offset treatment.
+					startLimit := nextEmit + 1
+
+					tMin := s - e.maxMatchOff
+					if tMin < 0 {
+						tMin = 0
+					}
+					for repIndex > tMin && start > startLimit && src[repIndex-1] == src[start-1] && seq.matchLen < maxMatchLength-zstdMinMatch-1 {
+						repIndex--
+						start--
+						seq.matchLen++
+					}
+					addLiterals(&seq, start)
+
+					// rep 2
+					seq.offset = 2
+					if debugSequences {
+						println("repeat sequence 2", seq, "next s:", s)
+					}
+					blk.sequences = append(blk.sequences, seq)
+
+					index0 := s + repOff2
+					s += lenght + repOff2
+					nextEmit = s
+					if s >= sLimit {
+						if debug {
+							println("repeat ended", s, lenght)
+
+						}
+						break encodeLoop
+					}
+
+					// Index skipped...
+					for index0 < s-1 {
+						cv0 := load6432(src, index0)
+						cv1 := cv0 >> 8
+						h0 := hash8(cv0, betterLongTableBits)
+						off := index0 + e.cur
+						e.longTable[h0] = prevEntry{offset: off, prev: e.longTable[h0].offset}
+						e.table[hash5(cv1, betterShortTableBits)] = tableEntry{offset: off + 1, val: uint32(cv1)}
+						index0 += 2
+					}
+					cv = load6432(src, s)
+					// Swap offsets
+					offset1, offset2 = offset2, offset1
+					continue
+				}
+			}
+			// Find the offsets of our two matches.
+			coffsetL := candidateL.offset - e.cur
+			coffsetLP := candidateL.prev - e.cur
+
+			// Check if we have a long match.
+			if s-coffsetL < e.maxMatchOff && cv == load6432(src, coffsetL) {
+				// Found a long match, at least 8 bytes.
+				matched = e.matchlen(s+8, coffsetL+8, src) + 8
+				t = coffsetL
+				if debugAsserts && s <= t {
+					panic(fmt.Sprintf("s (%d) <= t (%d)", s, t))
+				}
+				if debugAsserts && s-t > e.maxMatchOff {
+					panic("s - t >e.maxMatchOff")
+				}
+				if debugMatches {
+					println("long match")
+				}
+
+				if s-coffsetLP < e.maxMatchOff && cv == load6432(src, coffsetLP) {
+					// Found a long match, at least 8 bytes.
+					prevMatch := e.matchlen(s+8, coffsetLP+8, src) + 8
+					if prevMatch > matched {
+						matched = prevMatch
+						t = coffsetLP
+					}
+					if debugAsserts && s <= t {
+						panic(fmt.Sprintf("s (%d) <= t (%d)", s, t))
+					}
+					if debugAsserts && s-t > e.maxMatchOff {
+						panic("s - t >e.maxMatchOff")
+					}
+					if debugMatches {
+						println("long match")
+					}
+				}
+				break
+			}
+
+			// Check if we have a long match on prev.
+			if s-coffsetLP < e.maxMatchOff && cv == load6432(src, coffsetLP) {
+				// Found a long match, at least 8 bytes.
+				matched = e.matchlen(s+8, coffsetLP+8, src) + 8
+				t = coffsetLP
+				if debugAsserts && s <= t {
+					panic(fmt.Sprintf("s (%d) <= t (%d)", s, t))
+				}
+				if debugAsserts && s-t > e.maxMatchOff {
+					panic("s - t >e.maxMatchOff")
+				}
+				if debugMatches {
+					println("long match")
+				}
+				break
+			}
+
+			coffsetS := candidateS.offset - e.cur
+
+			// Check if we have a short match.
+			if s-coffsetS < e.maxMatchOff && uint32(cv) == candidateS.val {
+				// found a regular match
+				matched = e.matchlen(s+4, coffsetS+4, src) + 4
+
+				// See if we can find a long match at s+1
+				const checkAt = 1
+				cv := load6432(src, s+checkAt)
+				nextHashL = hash8(cv, betterLongTableBits)
+				candidateL = e.longTable[nextHashL]
+				coffsetL = candidateL.offset - e.cur
+
+				// We can store it, since we have at least a 4 byte match.
+				e.longTable[nextHashL] = prevEntry{offset: s + checkAt + e.cur, prev: candidateL.offset}
+				if s-coffsetL < e.maxMatchOff && cv == load6432(src, coffsetL) {
+					// Found a long match, at least 8 bytes.
+					matchedNext := e.matchlen(s+8+checkAt, coffsetL+8, src) + 8
+					if matchedNext > matched {
+						t = coffsetL
+						s += checkAt
+						matched = matchedNext
+						if debugMatches {
+							println("long match (after short)")
+						}
+						break
+					}
+				}
+
+				// Check prev long...
+				coffsetL = candidateL.prev - e.cur
+				if s-coffsetL < e.maxMatchOff && cv == load6432(src, coffsetL) {
+					// Found a long match, at least 8 bytes.
+					matchedNext := e.matchlen(s+8+checkAt, coffsetL+8, src) + 8
+					if matchedNext > matched {
+						t = coffsetL
+						s += checkAt
+						matched = matchedNext
+						if debugMatches {
+							println("prev long match (after short)")
+						}
+						break
+					}
+				}
+				t = coffsetS
+				if debugAsserts && s <= t {
+					panic(fmt.Sprintf("s (%d) <= t (%d)", s, t))
+				}
+				if debugAsserts && s-t > e.maxMatchOff {
+					panic("s - t >e.maxMatchOff")
+				}
+				if debugAsserts && t < 0 {
+					panic("t<0")
+				}
+				if debugMatches {
+					println("short match")
+				}
+				break
+			}
+
+			// No match found, move forward in input.
+			s += stepSize + ((s - nextEmit) >> (kSearchStrength - 1))
+			if s >= sLimit {
+				break encodeLoop
+			}
+			cv = load6432(src, s)
+		}
+
+		// A 4-byte match has been found. Update recent offsets.
+		// We'll later see if more than 4 bytes.
+		offset2 = offset1
+		offset1 = s - t
+
+		if debugAsserts && s <= t {
+			panic(fmt.Sprintf("s (%d) <= t (%d)", s, t))
+		}
+
+		if debugAsserts && canRepeat && int(offset1) > len(src) {
+			panic("invalid offset")
+		}
+
+		// Extend the n-byte match as long as possible.
+		l := matched
+
+		// Extend backwards
+		tMin := s - e.maxMatchOff
+		if tMin < 0 {
+			tMin = 0
+		}
+		for t > tMin && s > nextEmit && src[t-1] == src[s-1] && l < maxMatchLength {
+			s--
+			t--
+			l++
+		}
+
+		// Write our sequence
+		var seq seq
+		seq.litLen = uint32(s - nextEmit)
+		seq.matchLen = uint32(l - zstdMinMatch)
+		if seq.litLen > 0 {
+			blk.literals = append(blk.literals, src[nextEmit:s]...)
+		}
+		seq.offset = uint32(s-t) + 3
+		s += l
+		if debugSequences {
+			println("sequence", seq, "next s:", s)
+		}
+		blk.sequences = append(blk.sequences, seq)
+		nextEmit = s
+		if s >= sLimit {
+			break encodeLoop
+		}
+
+		// Index match start+1 (long) -> s - 1
+		index0 := s - l + 1
+		for index0 < s-1 {
+			cv0 := load6432(src, index0)
+			cv1 := cv0 >> 8
+			h0 := hash8(cv0, betterLongTableBits)
+			off := index0 + e.cur
+			e.longTable[h0] = prevEntry{offset: off, prev: e.longTable[h0].offset}
+			e.table[hash5(cv1, betterShortTableBits)] = tableEntry{offset: off + 1, val: uint32(cv1)}
+			index0 += 2
+		}
+
+		cv = load6432(src, s)
+		if !canRepeat {
+			continue
+		}
+
+		// Check offset 2
+		for {
+			o2 := s - offset2
+			if load3232(src, o2) != uint32(cv) {
+				// Do regular search
+				break
+			}
+
+			// Store this, since we have it.
+			nextHashS := hash5(cv, betterShortTableBits)
+			nextHashL := hash8(cv, betterLongTableBits)
+
+			// We have at least 4 byte match.
+			// No need to check backwards. We come straight from a match
+			l := 4 + e.matchlen(s+4, o2+4, src)
+
+			e.longTable[nextHashL] = prevEntry{offset: s + e.cur, prev: e.longTable[nextHashL].offset}
+			e.table[nextHashS] = tableEntry{offset: s + e.cur, val: uint32(cv)}
+			seq.matchLen = uint32(l) - zstdMinMatch
+			seq.litLen = 0
+
+			// Since litlen is always 0, this is offset 1.
+			seq.offset = 1
+			s += l
+			nextEmit = s
+			if debugSequences {
+				println("sequence", seq, "next s:", s)
+			}
+			blk.sequences = append(blk.sequences, seq)
+
+			// Swap offset 1 and 2.
+			offset1, offset2 = offset2, offset1
+			if s >= sLimit {
+				// Finished
+				break encodeLoop
+			}
+			cv = load6432(src, s)
+		}
+	}
+
+	if int(nextEmit) < len(src) {
+		blk.literals = append(blk.literals, src[nextEmit:]...)
+		blk.extraLits = len(src) - int(nextEmit)
+	}
+	blk.recentOffsets[0] = uint32(offset1)
+	blk.recentOffsets[1] = uint32(offset2)
+	if debug {
+		println("returning, recent offsets:", blk.recentOffsets, "extra literals:", blk.extraLits)
+	}
+}
+
+// EncodeNoHist will encode a block with no history and no following blocks.
+// Most notable difference is that src will not be copied for history and
+// we do not need to check for max match length.
+func (e *betterFastEncoder) EncodeNoHist(blk *blockEnc, src []byte) {
+	e.Encode(blk, src)
+}

vendor/github.com/klauspost/compress/zstd/enc_dfast.go

@@ -172,55 +172,6 @@ encodeLoop:
 					cv = load6432(src, s)
 					continue
 				}
-				const repOff2 = 1
-				// We deviate from the reference encoder and also check offset 2.
-				// Slower and not consistently better, so disabled.
-				// repIndex = s - offset2 + repOff2
-				if false && repIndex >= 0 && load3232(src, repIndex) == uint32(cv>>(repOff2*8)) {
-					// Consider history as well.
-					var seq seq
-					lenght := 4 + e.matchlen(s+4+repOff2, repIndex+4, src)
-
-					seq.matchLen = uint32(lenght - zstdMinMatch)
-
-					// We might be able to match backwards.
-					// Extend as long as we can.
-					start := s + repOff2
-					// We end the search early, so we don't risk 0 literals
-					// and have to do special offset treatment.
-					startLimit := nextEmit + 1
-
-					tMin := s - e.maxMatchOff
-					if tMin < 0 {
-						tMin = 0
-					}
-					for repIndex > tMin && start > startLimit && src[repIndex-1] == src[start-1] && seq.matchLen < maxMatchLength-zstdMinMatch-1 {
-						repIndex--
-						start--
-						seq.matchLen++
-					}
-					addLiterals(&seq, start)
-
-					// rep 2
-					seq.offset = 2
-					if debugSequences {
-						println("repeat sequence 2", seq, "next s:", s)
-					}
-					blk.sequences = append(blk.sequences, seq)
-					s += lenght + repOff2
-					nextEmit = s
-					if s >= sLimit {
-						if debug {
-							println("repeat ended", s, lenght)
-
-						}
-						break encodeLoop
-					}
-					cv = load6432(src, s)
-					// Swap offsets
-					offset1, offset2 = offset2, offset1
-					continue
-				}
 			}
 			// Find the offsets of our two matches.
 			coffsetL := s - (candidateL.offset - e.cur)
@@ -372,7 +323,7 @@ encodeLoop:
 			}
 
 			// Store this, since we have it.
-			nextHashS := hash5(cv1>>8, dFastShortTableBits)
+			nextHashS := hash5(cv, dFastShortTableBits)
 			nextHashL := hash8(cv, dFastLongTableBits)
 
 			// We have at least 4 byte match.

vendor/github.com/klauspost/compress/zstd/enc_fast.go

@@ -6,6 +6,7 @@ package zstd
 
 import (
 	"fmt"
+	"math"
 	"math/bits"
 
 	"github.com/klauspost/compress/zstd/internal/xxhash"
@@ -23,7 +24,7 @@ type tableEntry struct {
 	offset int32
 }
 
-type fastEncoder struct {
+type fastBase struct {
 	o encParams
 	// cur is the offset at the start of hist
 	cur int32
@@ -31,18 +32,22 @@ type fastEncoder struct {
 	maxMatchOff int32
 	hist        []byte
 	crc         *xxhash.Digest
-	table       [tableSize]tableEntry
 	tmp         [8]byte
 	blk         *blockEnc
 }
 
+type fastEncoder struct {
+	fastBase
+	table [tableSize]tableEntry
+}
+
 // CRC returns the underlying CRC writer.
-func (e *fastEncoder) CRC() *xxhash.Digest {
+func (e *fastBase) CRC() *xxhash.Digest {
 	return e.crc
 }
 
 // AppendCRC will append the CRC to the destination slice and return it.
-func (e *fastEncoder) AppendCRC(dst []byte) []byte {
+func (e *fastBase) AppendCRC(dst []byte) []byte {
 	crc := e.crc.Sum(e.tmp[:0])
 	dst = append(dst, crc[7], crc[6], crc[5], crc[4])
 	return dst
@@ -50,7 +55,7 @@ func (e *fastEncoder) AppendCRC(dst []byte) []byte {
 
 // WindowSize returns the window size of the encoder,
 // or a window size small enough to contain the input size, if > 0.
-func (e *fastEncoder) WindowSize(size int) int32 {
+func (e *fastBase) WindowSize(size int) int32 {
 	if size > 0 && size < int(e.maxMatchOff) {
 		b := int32(1) << uint(bits.Len(uint(size)))
 		// Keep minimum window.
@@ -63,7 +68,7 @@ func (e *fastEncoder) WindowSize(size int) int32 {
 }
 
 // Block returns the current block.
-func (e *fastEncoder) Block() *blockEnc {
+func (e *fastBase) Block() *blockEnc {
 	return e.blk
 }
 
@@ -169,9 +174,22 @@ encodeLoop:
 			if canRepeat && repIndex >= 0 && load3232(src, repIndex) == uint32(cv>>16) {
 				// Consider history as well.
 				var seq seq
-				lenght := 4 + e.matchlen(s+6, repIndex+4, src)
+				var length int32
+				// length = 4 + e.matchlen(s+6, repIndex+4, src)
+				{
+					a := src[s+6:]
+					b := src[repIndex+4:]
+					endI := len(a) & (math.MaxInt32 - 7)
+					length = int32(endI) + 4
+					for i := 0; i < endI; i += 8 {
+						if diff := load64(a, i) ^ load64(b, i); diff != 0 {
+							length = int32(i+bits.TrailingZeros64(diff)>>3) + 4
+							break
+						}
+					}
+				}
 
-				seq.matchLen = uint32(lenght - zstdMinMatch)
+				seq.matchLen = uint32(length - zstdMinMatch)
 
 				// We might be able to match backwards.
 				// Extend as long as we can.
@@ -197,11 +215,11 @@ encodeLoop:
 					println("repeat sequence", seq, "next s:", s)
 				}
 				blk.sequences = append(blk.sequences, seq)
-				s += lenght + 2
+				s += length + 2
 				nextEmit = s
 				if s >= sLimit {
 					if debug {
-						println("repeat ended", s, lenght)
+						println("repeat ended", s, length)
 
 					}
 					break encodeLoop
@@ -257,7 +275,20 @@ encodeLoop:
 		}
 
 		// Extend the 4-byte match as long as possible.
-		l := e.matchlen(s+4, t+4, src) + 4
+		//l := e.matchlen(s+4, t+4, src) + 4
+		var l int32
+		{
+			a := src[s+4:]
+			b := src[t+4:]
+			endI := len(a) & (math.MaxInt32 - 7)
+			l = int32(endI) + 4
+			for i := 0; i < endI; i += 8 {
+				if diff := load64(a, i) ^ load64(b, i); diff != 0 {
+					l = int32(i+bits.TrailingZeros64(diff)>>3) + 4
+					break
+				}
+			}
+		}
 
 		// Extend backwards
 		tMin := s - e.maxMatchOff
@@ -294,7 +325,20 @@ encodeLoop:
 		if o2 := s - offset2; canRepeat && load3232(src, o2) == uint32(cv) {
 			// We have at least 4 byte match.
 			// No need to check backwards. We come straight from a match
-			l := 4 + e.matchlen(s+4, o2+4, src)
+			//l := 4 + e.matchlen(s+4, o2+4, src)
+			var l int32
+			{
+				a := src[s+4:]
+				b := src[o2+4:]
+				endI := len(a) & (math.MaxInt32 - 7)
+				l = int32(endI) + 4
+				for i := 0; i < endI; i += 8 {
+					if diff := load64(a, i) ^ load64(b, i); diff != 0 {
+						l = int32(i+bits.TrailingZeros64(diff)>>3) + 4
+						break
+					}
+				}
+			}
 
 			// Store this, since we have it.
 			nextHash := hash6(cv, hashLog)
@@ -412,10 +456,23 @@ encodeLoop:
 			if len(blk.sequences) > 2 && load3232(src, repIndex) == uint32(cv>>16) {
 				// Consider history as well.
 				var seq seq
-				// lenght := 4 + e.matchlen(s+6, repIndex+4, src)
-				lenght := 4 + int32(matchLen(src[s+6:], src[repIndex+4:]))
+				// length := 4 + e.matchlen(s+6, repIndex+4, src)
+				// length := 4 + int32(matchLen(src[s+6:], src[repIndex+4:]))
+				var length int32
+				{
+					a := src[s+6:]
+					b := src[repIndex+4:]
+					endI := len(a) & (math.MaxInt32 - 7)
+					length = int32(endI) + 4
+					for i := 0; i < endI; i += 8 {
+						if diff := load64(a, i) ^ load64(b, i); diff != 0 {
+							length = int32(i+bits.TrailingZeros64(diff)>>3) + 4
+							break
+						}
+					}
+				}
 
-				seq.matchLen = uint32(lenght - zstdMinMatch)
+				seq.matchLen = uint32(length - zstdMinMatch)
 
 				// We might be able to match backwards.
 				// Extend as long as we can.
@@ -441,11 +498,11 @@ encodeLoop:
 					println("repeat sequence", seq, "next s:", s)
 				}
 				blk.sequences = append(blk.sequences, seq)
-				s += lenght + 2
+				s += length + 2
 				nextEmit = s
 				if s >= sLimit {
 					if debug {
-						println("repeat ended", s, lenght)
+						println("repeat ended", s, length)
 
 					}
 					break encodeLoop
@@ -498,7 +555,20 @@ encodeLoop:
 
 		// Extend the 4-byte match as long as possible.
 		//l := e.matchlenNoHist(s+4, t+4, src) + 4
-		l := int32(matchLen(src[s+4:], src[t+4:])) + 4
+		// l := int32(matchLen(src[s+4:], src[t+4:])) + 4
+		var l int32
+		{
+			a := src[s+4:]
+			b := src[t+4:]
+			endI := len(a) & (math.MaxInt32 - 7)
+			l = int32(endI) + 4
+			for i := 0; i < endI; i += 8 {
+				if diff := load64(a, i) ^ load64(b, i); diff != 0 {
+					l = int32(i+bits.TrailingZeros64(diff)>>3) + 4
+					break
+				}
+			}
+		}
 
 		// Extend backwards
 		tMin := s - e.maxMatchOff
@@ -536,7 +606,20 @@ encodeLoop:
 			// We have at least 4 byte match.
 			// No need to check backwards. We come straight from a match
 			//l := 4 + e.matchlenNoHist(s+4, o2+4, src)
-			l := 4 + int32(matchLen(src[s+4:], src[o2+4:]))
+			// l := 4 + int32(matchLen(src[s+4:], src[o2+4:]))
+			var l int32
+			{
+				a := src[s+4:]
+				b := src[o2+4:]
+				endI := len(a) & (math.MaxInt32 - 7)
+				l = int32(endI) + 4
+				for i := 0; i < endI; i += 8 {
+					if diff := load64(a, i) ^ load64(b, i); diff != 0 {
+						l = int32(i+bits.TrailingZeros64(diff)>>3) + 4
+						break
+					}
+				}
+			}
 
 			// Store this, since we have it.
 			nextHash := hash6(cv, hashLog)
@@ -571,7 +654,7 @@ encodeLoop:
 	}
 }
 
-func (e *fastEncoder) addBlock(src []byte) int32 {
+func (e *fastBase) addBlock(src []byte) int32 {
 	if debugAsserts && e.cur > bufferReset {
 		panic(fmt.Sprintf("ecur (%d) > buffer reset (%d)", e.cur, bufferReset))
 	}
@@ -602,17 +685,17 @@ func (e *fastEncoder) addBlock(src []byte) int32 {
 
 // useBlock will replace the block with the provided one,
 // but transfer recent offsets from the previous.
-func (e *fastEncoder) UseBlock(enc *blockEnc) {
+func (e *fastBase) UseBlock(enc *blockEnc) {
 	enc.reset(e.blk)
 	e.blk = enc
 }
 
-func (e *fastEncoder) matchlenNoHist(s, t int32, src []byte) int32 {
+func (e *fastBase) matchlenNoHist(s, t int32, src []byte) int32 {
 	// Extend the match to be as long as possible.
 	return int32(matchLen(src[s:], src[t:]))
 }
 
-func (e *fastEncoder) matchlen(s, t int32, src []byte) int32 {
+func (e *fastBase) matchlen(s, t int32, src []byte) int32 {
 	if debugAsserts {
 		if s < 0 {
 			err := fmt.Sprintf("s (%d) < 0", s)
@@ -626,18 +709,17 @@ func (e *fastEncoder) matchlen(s, t int32, src []byte) int32 {
 			err := fmt.Sprintf("s (%d) - t (%d) > maxMatchOff (%d)", s, t, e.maxMatchOff)
 			panic(err)
 		}
-	}
-	s1 := int(s) + maxMatchLength - 4
-	if s1 > len(src) {
-		s1 = len(src)
+		if len(src)-int(s) > maxCompressedBlockSize {
+			panic(fmt.Sprintf("len(src)-s (%d) > maxCompressedBlockSize (%d)", len(src)-int(s), maxCompressedBlockSize))
+		}
 	}
 
 	// Extend the match to be as long as possible.
-	return int32(matchLen(src[s:s1], src[t:]))
+	return int32(matchLen(src[s:], src[t:]))
 }
 
 // Reset the encoding table.
-func (e *fastEncoder) Reset() {
+func (e *fastBase) Reset() {
 	if e.blk == nil {
 		e.blk = &blockEnc{}
 		e.blk.init()

vendor/github.com/klauspost/compress/zstd/encoder.go

@@ -71,15 +71,14 @@ func NewWriter(w io.Writer, opts ...EOption) (*Encoder, error) {
 	}
 	if w != nil {
 		e.Reset(w)
-	} else {
-		e.init.Do(func() {
-			e.initialize()
-		})
 	}
 	return &e, nil
 }
 
 func (e *Encoder) initialize() {
+	if e.o.concurrent == 0 {
+		e.o.setDefault()
+	}
 	e.encoders = make(chan encoder, e.o.concurrent)
 	for i := 0; i < e.o.concurrent; i++ {
 		e.encoders <- e.o.encoder()
@@ -89,9 +88,6 @@ func (e *Encoder) initialize() {
 // Reset will re-initialize the writer and new writes will encode to the supplied writer
 // as a new, independent stream.
 func (e *Encoder) Reset(w io.Writer) {
-	e.init.Do(func() {
-		e.initialize()
-	})
 	s := &e.state
 	s.wg.Wait()
 	s.wWg.Wait()
@@ -422,10 +418,7 @@ func (e *Encoder) EncodeAll(src, dst []byte) []byte {
 		}
 		return dst
 	}
-	e.init.Do(func() {
-		e.o.setDefault()
-		e.initialize()
-	})
+	e.init.Do(e.initialize)
 	enc := <-e.encoders
 	defer func() {
 		// Release encoder reference to last block.

vendor/github.com/klauspost/compress/zstd/encoder_options.go

@@ -39,9 +39,11 @@ func (o *encoderOptions) setDefault() {
 func (o encoderOptions) encoder() encoder {
 	switch o.level {
 	case SpeedDefault:
-		return &doubleFastEncoder{fastEncoder: fastEncoder{maxMatchOff: int32(o.windowSize)}}
+		return &doubleFastEncoder{fastEncoder: fastEncoder{fastBase: fastBase{maxMatchOff: int32(o.windowSize)}}}
+	case SpeedBetterCompression:
+		return &betterFastEncoder{fastBase: fastBase{maxMatchOff: int32(o.windowSize)}}
 	case SpeedFastest:
-		return &fastEncoder{maxMatchOff: int32(o.windowSize)}
+		return &fastEncoder{fastBase: fastBase{maxMatchOff: int32(o.windowSize)}}
 	}
 	panic("unknown compression level")
 }
@@ -67,7 +69,7 @@ func WithEncoderConcurrency(n int) EOption {
 }
 
 // WithWindowSize will set the maximum allowed back-reference distance.
-// The value must be a power of two between WindowSizeMin and WindowSizeMax.
+// The value must be a power of two between MinWindowSize and MaxWindowSize.
 // A larger value will enable better compression but allocate more memory and,
 // for above-default values, take considerably longer.
 // The default value is determined by the compression level.
@@ -130,18 +132,18 @@ const (
 	// This is roughly equivalent to the default Zstandard mode (level 3).
 	SpeedDefault
 
+	// SpeedBetterCompression will yield better compression than the default.
+	// Currently it is about zstd level 7-8 with ~ 2x-3x the default CPU usage.
+	// By using this, notice that CPU usage may go up in the future.
+	SpeedBetterCompression
+
 	// speedLast should be kept as the last actual compression option.
 	// The is not for external usage, but is used to keep track of the valid options.
 	speedLast
 
-	// SpeedBetterCompression will (in the future) yield better compression than the default,
-	// but at approximately 4x the CPU usage of the default.
-	// For now this is not implemented.
-	SpeedBetterCompression = SpeedDefault
-
 	// SpeedBestCompression will choose the best available compression option.
 	// For now this is not implemented.
-	SpeedBestCompression = SpeedDefault
+	SpeedBestCompression = SpeedBetterCompression
 )
 
 // EncoderLevelFromString will convert a string representation of an encoding level back
@@ -163,8 +165,10 @@ func EncoderLevelFromZstd(level int) EncoderLevel {
 	switch {
 	case level < 3:
 		return SpeedFastest
-	case level >= 3:
+	case level >= 3 && level < 6:
 		return SpeedDefault
+	case level > 5:
+		return SpeedBetterCompression
 	}
 	return SpeedDefault
 }
@@ -176,6 +180,8 @@ func (e EncoderLevel) String() string {
 		return "fastest"
 	case SpeedDefault:
 		return "default"
+	case SpeedBetterCompression:
+		return "better"
 	default:
 		return "invalid"
 	}

vendor/github.com/klauspost/compress/zstd/zstd.go

@@ -87,6 +87,17 @@ func printf(format string, a ...interface{}) {
 	}
 }
 
+// matchLenFast does matching, but will not match the last up to 7 bytes.
+func matchLenFast(a, b []byte) int {
+	endI := len(a) & (math.MaxInt32 - 7)
+	for i := 0; i < endI; i += 8 {
+		if diff := load64(a, i) ^ load64(b, i); diff != 0 {
+			return i + bits.TrailingZeros64(diff)>>3
+		}
+	}
+	return endI
+}
+
 // matchLen returns the maximum length.
 // a must be the shortest of the two.
 // The function also returns whether all bytes matched.
@@ -97,33 +108,18 @@ func matchLen(a, b []byte) int {
 			return i + (bits.TrailingZeros64(diff) >> 3)
 		}
 	}
+
 	checked := (len(a) >> 3) << 3
 	a = a[checked:]
 	b = b[checked:]
-	// TODO: We could do a 4 check.
 	for i := range a {
 		if a[i] != b[i] {
-			return int(i) + checked
+			return i + checked
 		}
 	}
 	return len(a) + checked
 }
 
-// matchLen returns a match length in src between index s and t
-func matchLenIn(src []byte, s, t int32) int32 {
-	s1 := len(src)
-	b := src[t:]
-	a := src[s:s1]
-	b = b[:len(a)]
-	// Extend the match to be as long as possible.
-	for i := range a {
-		if a[i] != b[i] {
-			return int32(i)
-		}
-	}
-	return int32(len(a))
-}
-
 func load3232(b []byte, i int32) uint32 {
 	// Help the compiler eliminate bounds checks on the read so it can be done in a single read.
 	b = b[i:]