Vendor in containers/common@main

Signed-off-by: Ashley Cui <acui@redhat.com>

8 files changed, 700 insertions, 505 deletions

diff --git a/vendor/github.com/klauspost/compress/flate/fast_encoder.go b/vendor/github.com/klauspost/compress/flate/fast_encoder.go
index 0b2e54972..d55ea2a77 100644
--- a/vendor/github.com/klauspost/compress/flate/fast_encoder.go
+++ b/vendor/github.com/klauspost/compress/flate/fast_encoder.go
@@ -179,7 +179,7 @@ func (e *fastGen) matchlen(s, t int32, src []byte) int32 {
 // matchlenLong will return the match length between offsets and t in src.
 // It is assumed that s > t, that t >=0 and s < len(src).
 func (e *fastGen) matchlenLong(s, t int32, src []byte) int32 {
-	if debugDecode {
+	if debugDeflate {
 		if t >= s {
 			panic(fmt.Sprint("t >=s:", t, s))
 		}
diff --git a/vendor/github.com/klauspost/compress/flate/huffman_bit_writer.go b/vendor/github.com/klauspost/compress/flate/huffman_bit_writer.go
index fd49efd75..25f6d1108 100644
--- a/vendor/github.com/klauspost/compress/flate/huffman_bit_writer.go
+++ b/vendor/github.com/klauspost/compress/flate/huffman_bit_writer.go
@@ -8,6 +8,7 @@ import (
 	"encoding/binary"
 	"fmt"
 	"io"
+	"math"
 )
 
 const (
@@ -24,6 +25,10 @@ const (
 	codegenCodeCount = 19
 	badCode          = 255
 
+	// maxPredefinedTokens is the maximum number of tokens
+	// where we check if fixed size is smaller.
+	maxPredefinedTokens = 250
+
 	// bufferFlushSize indicates the buffer size
 	// after which bytes are flushed to the writer.
 	// Should preferably be a multiple of 6, since
@@ -36,8 +41,11 @@ const (
 	bufferSize = bufferFlushSize + 8
 )
 
+// Minimum length code that emits bits.
+const lengthExtraBitsMinCode = 8
+
 // The number of extra bits needed by length code X - LENGTH_CODES_START.
-var lengthExtraBits = [32]int8{
+var lengthExtraBits = [32]uint8{
 	/* 257 */ 0, 0, 0,
 	/* 260 */ 0, 0, 0, 0, 0, 1, 1, 1, 1, 2,
 	/* 270 */ 2, 2, 2, 3, 3, 3, 3, 4, 4, 4,
@@ -51,6 +59,9 @@ var lengthBase = [32]uint8{
 	64, 80, 96, 112, 128, 160, 192, 224, 255,
 }
 
+// Minimum offset code that emits bits.
+const offsetExtraBitsMinCode = 4
+
 // offset code word extra bits.
 var offsetExtraBits = [32]int8{
 	0, 0, 0, 0, 1, 1, 2, 2, 3, 3,
@@ -78,10 +89,10 @@ func init() {
 
 	for i := range offsetCombined[:] {
 		// Don't use extended window values...
-		if offsetBase[i] > 0x006000 {
+		if offsetExtraBits[i] == 0 || offsetBase[i] > 0x006000 {
 			continue
 		}
-		offsetCombined[i] = uint32(offsetExtraBits[i])<<16 | (offsetBase[i])
+		offsetCombined[i] = uint32(offsetExtraBits[i]) | (offsetBase[i] << 8)
 	}
 }
 
@@ -97,7 +108,7 @@ type huffmanBitWriter struct {
 	// Data waiting to be written is bytes[0:nbytes]
 	// and then the low nbits of bits.
 	bits            uint64
-	nbits           uint16
+	nbits           uint8
 	nbytes          uint8
 	lastHuffMan     bool
 	literalEncoding *huffmanEncoder
@@ -215,7 +226,7 @@ func (w *huffmanBitWriter) write(b []byte) {
 	_, w.err = w.writer.Write(b)
 }
 
-func (w *huffmanBitWriter) writeBits(b int32, nb uint16) {
+func (w *huffmanBitWriter) writeBits(b int32, nb uint8) {
 	w.bits |= uint64(b) << (w.nbits & 63)
 	w.nbits += nb
 	if w.nbits >= 48 {
@@ -571,7 +582,10 @@ func (w *huffmanBitWriter) writeBlock(tokens *tokens, eof bool, input []byte) {
 	// Fixed Huffman baseline.
 	var literalEncoding = fixedLiteralEncoding
 	var offsetEncoding = fixedOffsetEncoding
-	var size = w.fixedSize(extraBits)
+	var size = math.MaxInt32
+	if tokens.n < maxPredefinedTokens {
+		size = w.fixedSize(extraBits)
+	}
 
 	// Dynamic Huffman?
 	var numCodegens int
@@ -672,19 +686,21 @@ func (w *huffmanBitWriter) writeBlockDynamic(tokens *tokens, eof bool, input []b
 			size = reuseSize
 		}
 
-		if preSize := w.fixedSize(extraBits) + 7; usePrefs && preSize < size {
-			// Check if we get a reasonable size decrease.
-			if storable && ssize <= size {
-				w.writeStoredHeader(len(input), eof)
-				w.writeBytes(input)
+		if tokens.n < maxPredefinedTokens {
+			if preSize := w.fixedSize(extraBits) + 7; usePrefs && preSize < size {
+				// Check if we get a reasonable size decrease.
+				if storable && ssize <= size {
+					w.writeStoredHeader(len(input), eof)
+					w.writeBytes(input)
+					return
+				}
+				w.writeFixedHeader(eof)
+				if !sync {
+					tokens.AddEOB()
+				}
+				w.writeTokens(tokens.Slice(), fixedLiteralEncoding.codes, fixedOffsetEncoding.codes)
 				return
 			}
-			w.writeFixedHeader(eof)
-			if !sync {
-				tokens.AddEOB()
-			}
-			w.writeTokens(tokens.Slice(), fixedLiteralEncoding.codes, fixedOffsetEncoding.codes)
-			return
 		}
 		// Check if we get a reasonable size decrease.
 		if storable && ssize <= size {
@@ -717,19 +733,21 @@ func (w *huffmanBitWriter) writeBlockDynamic(tokens *tokens, eof bool, input []b
 		size, numCodegens = w.dynamicSize(w.literalEncoding, w.offsetEncoding, extraBits)
 
 		// Store predefined, if we don't get a reasonable improvement.
-		if preSize := w.fixedSize(extraBits); usePrefs && preSize <= size {
-			// Store bytes, if we don't get an improvement.
-			if storable && ssize <= preSize {
-				w.writeStoredHeader(len(input), eof)
-				w.writeBytes(input)
+		if tokens.n < maxPredefinedTokens {
+			if preSize := w.fixedSize(extraBits); usePrefs && preSize <= size {
+				// Store bytes, if we don't get an improvement.
+				if storable && ssize <= preSize {
+					w.writeStoredHeader(len(input), eof)
+					w.writeBytes(input)
+					return
+				}
+				w.writeFixedHeader(eof)
+				if !sync {
+					tokens.AddEOB()
+				}
+				w.writeTokens(tokens.Slice(), fixedLiteralEncoding.codes, fixedOffsetEncoding.codes)
 				return
 			}
-			w.writeFixedHeader(eof)
-			if !sync {
-				tokens.AddEOB()
-			}
-			w.writeTokens(tokens.Slice(), fixedLiteralEncoding.codes, fixedOffsetEncoding.codes)
-			return
 		}
 
 		if storable && ssize <= size {
@@ -833,9 +851,9 @@ func (w *huffmanBitWriter) writeTokens(tokens []token, leCodes, oeCodes []hcode)
 	bits, nbits, nbytes := w.bits, w.nbits, w.nbytes
 
 	for _, t := range tokens {
-		if t < matchType {
+		if t < 256 {
 			//w.writeCode(lits[t.literal()])
-			c := lits[t.literal()]
+			c := lits[t]
 			bits |= uint64(c.code) << (nbits & 63)
 			nbits += c.len
 			if nbits >= 48 {
@@ -858,12 +876,12 @@ func (w *huffmanBitWriter) writeTokens(tokens []token, leCodes, oeCodes []hcode)
 
 		// Write the length
 		length := t.length()
-		lengthCode := lengthCode(length)
+		lengthCode := lengthCode(length) & 31
 		if false {
-			w.writeCode(lengths[lengthCode&31])
+			w.writeCode(lengths[lengthCode])
 		} else {
 			// inlined
-			c := lengths[lengthCode&31]
+			c := lengths[lengthCode]
 			bits |= uint64(c.code) << (nbits & 63)
 			nbits += c.len
 			if nbits >= 48 {
@@ -883,10 +901,10 @@ func (w *huffmanBitWriter) writeTokens(tokens []token, leCodes, oeCodes []hcode)
 			}
 		}
 
-		extraLengthBits := uint16(lengthExtraBits[lengthCode&31])
-		if extraLengthBits > 0 {
+		if lengthCode >= lengthExtraBitsMinCode {
+			extraLengthBits := lengthExtraBits[lengthCode]
 			//w.writeBits(extraLength, extraLengthBits)
-			extraLength := int32(length - lengthBase[lengthCode&31])
+			extraLength := int32(length - lengthBase[lengthCode])
 			bits |= uint64(extraLength) << (nbits & 63)
 			nbits += extraLengthBits
 			if nbits >= 48 {
@@ -907,10 +925,9 @@ func (w *huffmanBitWriter) writeTokens(tokens []token, leCodes, oeCodes []hcode)
 		}
 		// Write the offset
 		offset := t.offset()
-		offsetCode := offset >> 16
-		offset &= matchOffsetOnlyMask
+		offsetCode := (offset >> 16) & 31
 		if false {
-			w.writeCode(offs[offsetCode&31])
+			w.writeCode(offs[offsetCode])
 		} else {
 			// inlined
 			c := offs[offsetCode]
@@ -932,11 +949,12 @@ func (w *huffmanBitWriter) writeTokens(tokens []token, leCodes, oeCodes []hcode)
 				}
 			}
 		}
-		offsetComb := offsetCombined[offsetCode]
-		if offsetComb > 1<<16 {
+
+		if offsetCode >= offsetExtraBitsMinCode {
+			offsetComb := offsetCombined[offsetCode]
 			//w.writeBits(extraOffset, extraOffsetBits)
-			bits |= uint64(offset-(offsetComb&0xffff)) << (nbits & 63)
-			nbits += uint16(offsetComb >> 16)
+			bits |= uint64((offset-(offsetComb>>8))&matchOffsetOnlyMask) << (nbits & 63)
+			nbits += uint8(offsetComb)
 			if nbits >= 48 {
 				binary.LittleEndian.PutUint64(w.bytes[nbytes:], bits)
 				//*(*uint64)(unsafe.Pointer(&w.bytes[nbytes])) = bits
@@ -1002,6 +1020,29 @@ func (w *huffmanBitWriter) writeBlockHuff(eof bool, input []byte, sync bool) {
 	// https://stackoverflow.com/a/25454430
 	const guessHeaderSizeBits = 70 * 8
 	histogram(input, w.literalFreq[:numLiterals], fill)
+	ssize, storable := w.storedSize(input)
+	if storable && len(input) > 1024 {
+		// Quick check for incompressible content.
+		abs := float64(0)
+		avg := float64(len(input)) / 256
+		max := float64(len(input) * 2)
+		for _, v := range w.literalFreq[:256] {
+			diff := float64(v) - avg
+			abs += diff * diff
+			if abs > max {
+				break
+			}
+		}
+		if abs < max {
+			if debugDeflate {
+				fmt.Println("stored", abs, "<", max)
+			}
+			// No chance we can compress this...
+			w.writeStoredHeader(len(input), eof)
+			w.writeBytes(input)
+			return
+		}
+	}
 	w.literalFreq[endBlockMarker] = 1
 	w.tmpLitEncoding.generate(w.literalFreq[:numLiterals], 15)
 	if fill {
@@ -1019,8 +1060,10 @@ func (w *huffmanBitWriter) writeBlockHuff(eof bool, input []byte, sync bool) {
 	estBits += estBits >> w.logNewTablePenalty
 
 	// Store bytes, if we don't get a reasonable improvement.
-	ssize, storable := w.storedSize(input)
 	if storable && ssize <= estBits {
+		if debugDeflate {
+			fmt.Println("stored,", ssize, "<=", estBits)
+		}
 		w.writeStoredHeader(len(input), eof)
 		w.writeBytes(input)
 		return
@@ -1031,7 +1074,7 @@ func (w *huffmanBitWriter) writeBlockHuff(eof bool, input []byte, sync bool) {
 
 		if estBits < reuseSize {
 			if debugDeflate {
-				//fmt.Println("not reusing, reuse:", reuseSize/8, "> new:", estBits/8, "- header est:", w.lastHeader/8)
+				fmt.Println("NOT reusing, reuse:", reuseSize/8, "> new:", estBits/8, "header est:", w.lastHeader/8, "bytes")
 			}
 			// We owe an EOB
 			w.writeCode(w.literalEncoding.codes[endBlockMarker])
@@ -1065,6 +1108,9 @@ func (w *huffmanBitWriter) writeBlockHuff(eof bool, input []byte, sync bool) {
 	// Go 1.16 LOVES having these on stack. At least 1.5x the speed.
 	bits, nbits, nbytes := w.bits, w.nbits, w.nbytes
 
+	if debugDeflate {
+		count -= int(nbytes)*8 + int(nbits)
+	}
 	// Unroll, write 3 codes/loop.
 	// Fastest number of unrolls.
 	for len(input) > 3 {
@@ -1074,13 +1120,16 @@ func (w *huffmanBitWriter) writeBlockHuff(eof bool, input []byte, sync bool) {
 			binary.LittleEndian.PutUint64(w.bytes[nbytes:], bits)
 			bits >>= (n * 8) & 63
 			nbits -= n * 8
-			nbytes += uint8(n)
+			nbytes += n
 		}
 		if nbytes >= bufferFlushSize {
 			if w.err != nil {
 				nbytes = 0
 				return
 			}
+			if debugDeflate {
+				count += int(nbytes) * 8
+			}
 			_, w.err = w.writer.Write(w.bytes[:nbytes])
 			nbytes = 0
 		}
@@ -1096,13 +1145,6 @@ func (w *huffmanBitWriter) writeBlockHuff(eof bool, input []byte, sync bool) {
 
 	// Remaining...
 	for _, t := range input {
-		// Bitwriting inlined, ~30% speedup
-		c := encoding[t]
-		bits |= uint64(c.code) << (nbits & 63)
-		nbits += c.len
-		if debugDeflate {
-			count += int(c.len)
-		}
 		if nbits >= 48 {
 			binary.LittleEndian.PutUint64(w.bytes[nbytes:], bits)
 			//*(*uint64)(unsafe.Pointer(&w.bytes[nbytes])) = bits
@@ -1114,17 +1156,33 @@ func (w *huffmanBitWriter) writeBlockHuff(eof bool, input []byte, sync bool) {
 					nbytes = 0
 					return
 				}
+				if debugDeflate {
+					count += int(nbytes) * 8
+				}
 				_, w.err = w.writer.Write(w.bytes[:nbytes])
 				nbytes = 0
 			}
 		}
+		// Bitwriting inlined, ~30% speedup
+		c := encoding[t]
+		bits |= uint64(c.code) << (nbits & 63)
+		nbits += c.len
+		if debugDeflate {
+			count += int(c.len)
+		}
 	}
 	// Restore...
 	w.bits, w.nbits, w.nbytes = bits, nbits, nbytes
 
 	if debugDeflate {
-		fmt.Println("wrote", count/8, "bytes")
+		nb := count + int(nbytes)*8 + int(nbits)
+		fmt.Println("wrote", nb, "bits,", nb/8, "bytes.")
+	}
+	// Flush if needed to have space.
+	if w.nbits >= 48 {
+		w.writeOutBits()
 	}
+
 	if eof || sync {
 		w.writeCode(w.literalEncoding.codes[endBlockMarker])
 		w.lastHeader = 0
diff --git a/vendor/github.com/klauspost/compress/flate/huffman_code.go b/vendor/github.com/klauspost/compress/flate/huffman_code.go
index f35e00261..9ab497c27 100644
--- a/vendor/github.com/klauspost/compress/flate/huffman_code.go
+++ b/vendor/github.com/klauspost/compress/flate/huffman_code.go
@@ -17,7 +17,8 @@ const (
 
 // hcode is a huffman code with a bit code and bit length.
 type hcode struct {
-	code, len uint16
+	code uint16
+	len  uint8
 }
 
 type huffmanEncoder struct {
@@ -56,7 +57,7 @@ type levelInfo struct {
 }
 
 // set sets the code and length of an hcode.
-func (h *hcode) set(code uint16, length uint16) {
+func (h *hcode) set(code uint16, length uint8) {
 	h.len = length
 	h.code = code
 }
@@ -80,7 +81,7 @@ func generateFixedLiteralEncoding() *huffmanEncoder {
 	var ch uint16
 	for ch = 0; ch < literalCount; ch++ {
 		var bits uint16
-		var size uint16
+		var size uint8
 		switch {
 		case ch < 144:
 			// size 8, 000110000  .. 10111111
@@ -99,7 +100,7 @@ func generateFixedLiteralEncoding() *huffmanEncoder {
 			bits = ch + 192 - 280
 			size = 8
 		}
-		codes[ch] = hcode{code: reverseBits(bits, byte(size)), len: size}
+		codes[ch] = hcode{code: reverseBits(bits, size), len: size}
 	}
 	return h
 }
@@ -187,14 +188,19 @@ func (h *huffmanEncoder) bitCounts(list []literalNode, maxBits int32) []int32 {
 	// of the level j ancestor.
 	var leafCounts [maxBitsLimit][maxBitsLimit]int32
 
+	// Descending to only have 1 bounds check.
+	l2f := int32(list[2].freq)
+	l1f := int32(list[1].freq)
+	l0f := int32(list[0].freq) + int32(list[1].freq)
+
 	for level := int32(1); level <= maxBits; level++ {
 		// For every level, the first two items are the first two characters.
 		// We initialize the levels as if we had already figured this out.
 		levels[level] = levelInfo{
 			level:        level,
-			lastFreq:     int32(list[1].freq),
-			nextCharFreq: int32(list[2].freq),
-			nextPairFreq: int32(list[0].freq) + int32(list[1].freq),
+			lastFreq:     l1f,
+			nextCharFreq: l2f,
+			nextPairFreq: l0f,
 		}
 		leafCounts[level][level] = 2
 		if level == 1 {
@@ -205,8 +211,8 @@ func (h *huffmanEncoder) bitCounts(list []literalNode, maxBits int32) []int32 {
 	// We need a total of 2*n - 2 items at top level and have already generated 2.
 	levels[maxBits].needed = 2*n - 4
 
-	level := maxBits
-	for {
+	level := uint32(maxBits)
+	for level < 16 {
 		l := &levels[level]
 		if l.nextPairFreq == math.MaxInt32 && l.nextCharFreq == math.MaxInt32 {
 			// We've run out of both leafs and pairs.
@@ -238,7 +244,13 @@ func (h *huffmanEncoder) bitCounts(list []literalNode, maxBits int32) []int32 {
 			// more values in the level below
 			l.lastFreq = l.nextPairFreq
 			// Take leaf counts from the lower level, except counts[level] remains the same.
-			copy(leafCounts[level][:level], leafCounts[level-1][:level])
+			if true {
+				save := leafCounts[level][level]
+				leafCounts[level] = leafCounts[level-1]
+				leafCounts[level][level] = save
+			} else {
+				copy(leafCounts[level][:level], leafCounts[level-1][:level])
+			}
 			levels[l.level-1].needed = 2
 		}
 
@@ -296,7 +308,7 @@ func (h *huffmanEncoder) assignEncodingAndSize(bitCount []int32, list []literalN
 
 		sortByLiteral(chunk)
 		for _, node := range chunk {
-			h.codes[node.literal] = hcode{code: reverseBits(code, uint8(n)), len: uint16(n)}
+			h.codes[node.literal] = hcode{code: reverseBits(code, uint8(n)), len: uint8(n)}
 			code++
 		}
 		list = list[0 : len(list)-int(bits)]
@@ -309,6 +321,7 @@ func (h *huffmanEncoder) assignEncodingAndSize(bitCount []int32, list []literalN
 // maxBits  The maximum number of bits to use for any literal.
 func (h *huffmanEncoder) generate(freq []uint16, maxBits int32) {
 	list := h.freqcache[:len(freq)+1]
+	codes := h.codes[:len(freq)]
 	// Number of non-zero literals
 	count := 0
 	// Set list to be the set of all non-zero literals and their frequencies
@@ -317,11 +330,10 @@ func (h *huffmanEncoder) generate(freq []uint16, maxBits int32) {
 			list[count] = literalNode{uint16(i), f}
 			count++
 		} else {
-			list[count] = literalNode{}
-			h.codes[i].len = 0
+			codes[i].len = 0
 		}
 	}
-	list[len(freq)] = literalNode{}
+	list[count] = literalNode{}
 
 	list = list[:count]
 	if count <= 2 {
diff --git a/vendor/github.com/klauspost/compress/flate/inflate.go b/vendor/github.com/klauspost/compress/flate/inflate.go
index d5f62f6a2..414c0bea9 100644
--- a/vendor/github.com/klauspost/compress/flate/inflate.go
+++ b/vendor/github.com/klauspost/compress/flate/inflate.go
@@ -36,6 +36,13 @@ type lengthExtra struct {
 
 var decCodeToLen = [32]lengthExtra{{length: 0x0, extra: 0x0}, {length: 0x1, extra: 0x0}, {length: 0x2, extra: 0x0}, {length: 0x3, extra: 0x0}, {length: 0x4, extra: 0x0}, {length: 0x5, extra: 0x0}, {length: 0x6, extra: 0x0}, {length: 0x7, extra: 0x0}, {length: 0x8, extra: 0x1}, {length: 0xa, extra: 0x1}, {length: 0xc, extra: 0x1}, {length: 0xe, extra: 0x1}, {length: 0x10, extra: 0x2}, {length: 0x14, extra: 0x2}, {length: 0x18, extra: 0x2}, {length: 0x1c, extra: 0x2}, {length: 0x20, extra: 0x3}, {length: 0x28, extra: 0x3}, {length: 0x30, extra: 0x3}, {length: 0x38, extra: 0x3}, {length: 0x40, extra: 0x4}, {length: 0x50, extra: 0x4}, {length: 0x60, extra: 0x4}, {length: 0x70, extra: 0x4}, {length: 0x80, extra: 0x5}, {length: 0xa0, extra: 0x5}, {length: 0xc0, extra: 0x5}, {length: 0xe0, extra: 0x5}, {length: 0xff, extra: 0x0}, {length: 0x0, extra: 0x0}, {length: 0x0, extra: 0x0}, {length: 0x0, extra: 0x0}}
 
+var bitMask32 = [32]uint32{
+	0, 1, 3, 7, 0xF, 0x1F, 0x3F, 0x7F, 0xFF,
+	0x1FF, 0x3FF, 0x7FF, 0xFFF, 0x1FFF, 0x3FFF, 0x7FFF, 0xFFFF,
+	0x1ffff, 0x3ffff, 0x7FFFF, 0xfFFFF, 0x1fFFFF, 0x3fFFFF, 0x7fFFFF, 0xffFFFF,
+	0x1ffFFFF, 0x3ffFFFF, 0x7ffFFFF, 0xfffFFFF, 0x1fffFFFF, 0x3fffFFFF, 0x7fffFFFF,
+} // up to 32 bits
+
 // Initialize the fixedHuffmanDecoder only once upon first use.
 var fixedOnce sync.Once
 var fixedHuffmanDecoder huffmanDecoder
@@ -559,221 +566,6 @@ func (f *decompressor) readHuffman() error {
 	return nil
 }
 
-// Decode a single Huffman block from f.
-// hl and hd are the Huffman states for the lit/length values
-// and the distance values, respectively. If hd == nil, using the
-// fixed distance encoding associated with fixed Huffman blocks.
-func (f *decompressor) huffmanBlockGeneric() {
-	const (
-		stateInit = iota // Zero value must be stateInit
-		stateDict
-	)
-
-	switch f.stepState {
-	case stateInit:
-		goto readLiteral
-	case stateDict:
-		goto copyHistory
-	}
-
-readLiteral:
-	// Read literal and/or (length, distance) according to RFC section 3.2.3.
-	{
-		var v int
-		{
-			// Inlined v, err := f.huffSym(f.hl)
-			// Since a huffmanDecoder can be empty or be composed of a degenerate tree
-			// with single element, huffSym must error on these two edge cases. In both
-			// cases, the chunks slice will be 0 for the invalid sequence, leading it
-			// satisfy the n == 0 check below.
-			n := uint(f.hl.maxRead)
-			// Optimization. Compiler isn't smart enough to keep f.b,f.nb in registers,
-			// but is smart enough to keep local variables in registers, so use nb and b,
-			// inline call to moreBits and reassign b,nb back to f on return.
-			nb, b := f.nb, f.b
-			for {
-				for nb < n {
-					c, err := f.r.ReadByte()
-					if err != nil {
-						f.b = b
-						f.nb = nb
-						f.err = noEOF(err)
-						return
-					}
-					f.roffset++
-					b |= uint32(c) << (nb & regSizeMaskUint32)
-					nb += 8
-				}
-				chunk := f.hl.chunks[b&(huffmanNumChunks-1)]
-				n = uint(chunk & huffmanCountMask)
-				if n > huffmanChunkBits {
-					chunk = f.hl.links[chunk>>huffmanValueShift][(b>>huffmanChunkBits)&f.hl.linkMask]
-					n = uint(chunk & huffmanCountMask)
-				}
-				if n <= nb {
-					if n == 0 {
-						f.b = b
-						f.nb = nb
-						if debugDecode {
-							fmt.Println("huffsym: n==0")
-						}
-						f.err = CorruptInputError(f.roffset)
-						return
-					}
-					f.b = b >> (n & regSizeMaskUint32)
-					f.nb = nb - n
-					v = int(chunk >> huffmanValueShift)
-					break
-				}
-			}
-		}
-
-		var n uint // number of bits extra
-		var length int
-		var err error
-		switch {
-		case v < 256:
-			f.dict.writeByte(byte(v))
-			if f.dict.availWrite() == 0 {
-				f.toRead = f.dict.readFlush()
-				f.step = (*decompressor).huffmanBlockGeneric
-				f.stepState = stateInit
-				return
-			}
-			goto readLiteral
-		case v == 256:
-			f.finishBlock()
-			return
-		// otherwise, reference to older data
-		case v < 265:
-			length = v - (257 - 3)
-			n = 0
-		case v < 269:
-			length = v*2 - (265*2 - 11)
-			n = 1
-		case v < 273:
-			length = v*4 - (269*4 - 19)
-			n = 2
-		case v < 277:
-			length = v*8 - (273*8 - 35)
-			n = 3
-		case v < 281:
-			length = v*16 - (277*16 - 67)
-			n = 4
-		case v < 285:
-			length = v*32 - (281*32 - 131)
-			n = 5
-		case v < maxNumLit:
-			length = 258
-			n = 0
-		default:
-			if debugDecode {
-				fmt.Println(v, ">= maxNumLit")
-			}
-			f.err = CorruptInputError(f.roffset)
-			return
-		}
-		if n > 0 {
-			for f.nb < n {
-				if err = f.moreBits(); err != nil {
-					if debugDecode {
-						fmt.Println("morebits n>0:", err)
-					}
-					f.err = err
-					return
-				}
-			}
-			length += int(f.b & uint32(1<<(n&regSizeMaskUint32)-1))
-			f.b >>= n & regSizeMaskUint32
-			f.nb -= n
-		}
-
-		var dist uint32
-		if f.hd == nil {
-			for f.nb < 5 {
-				if err = f.moreBits(); err != nil {
-					if debugDecode {
-						fmt.Println("morebits f.nb<5:", err)
-					}
-					f.err = err
-					return
-				}
-			}
-			dist = uint32(bits.Reverse8(uint8(f.b & 0x1F << 3)))
-			f.b >>= 5
-			f.nb -= 5
-		} else {
-			sym, err := f.huffSym(f.hd)
-			if err != nil {
-				if debugDecode {
-					fmt.Println("huffsym:", err)
-				}
-				f.err = err
-				return
-			}
-			dist = uint32(sym)
-		}
-
-		switch {
-		case dist < 4:
-			dist++
-		case dist < maxNumDist:
-			nb := uint(dist-2) >> 1
-			// have 1 bit in bottom of dist, need nb more.
-			extra := (dist & 1) << (nb & regSizeMaskUint32)
-			for f.nb < nb {
-				if err = f.moreBits(); err != nil {
-					if debugDecode {
-						fmt.Println("morebits f.nb<nb:", err)
-					}
-					f.err = err
-					return
-				}
-			}
-			extra |= f.b & uint32(1<<(nb&regSizeMaskUint32)-1)
-			f.b >>= nb & regSizeMaskUint32
-			f.nb -= nb
-			dist = 1<<((nb+1)&regSizeMaskUint32) + 1 + extra
-		default:
-			if debugDecode {
-				fmt.Println("dist too big:", dist, maxNumDist)
-			}
-			f.err = CorruptInputError(f.roffset)
-			return
-		}
-
-		// No check on length; encoding can be prescient.
-		if dist > uint32(f.dict.histSize()) {
-			if debugDecode {
-				fmt.Println("dist > f.dict.histSize():", dist, f.dict.histSize())
-			}
-			f.err = CorruptInputError(f.roffset)
-			return
-		}
-
-		f.copyLen, f.copyDist = length, int(dist)
-		goto copyHistory
-	}
-
-copyHistory:
-	// Perform a backwards copy according to RFC section 3.2.3.
-	{
-		cnt := f.dict.tryWriteCopy(f.copyDist, f.copyLen)
-		if cnt == 0 {
-			cnt = f.dict.writeCopy(f.copyDist, f.copyLen)
-		}
-		f.copyLen -= cnt
-
-		if f.dict.availWrite() == 0 || f.copyLen > 0 {
-			f.toRead = f.dict.readFlush()
-			f.step = (*decompressor).huffmanBlockGeneric // We need to continue this work
-			f.stepState = stateDict
-			return
-		}
-		goto readLiteral
-	}
-}
-
 // Copy a single uncompressed data block from input to output.
 func (f *decompressor) dataBlock() {
 	// Uncompressed.
diff --git a/vendor/github.com/klauspost/compress/flate/inflate_gen.go b/vendor/github.com/klauspost/compress/flate/inflate_gen.go
index cc6db2792..8d632cea0 100644
--- a/vendor/github.com/klauspost/compress/flate/inflate_gen.go
+++ b/vendor/github.com/klauspost/compress/flate/inflate_gen.go
@@ -21,6 +21,11 @@ func (f *decompressor) huffmanBytesBuffer() {
 	)
 	fr := f.r.(*bytes.Buffer)
 
+	// Optimization. Compiler isn't smart enough to keep f.b,f.nb in registers,
+	// but is smart enough to keep local variables in registers, so use nb and b,
+	// inline call to moreBits and reassign b,nb back to f on return.
+	fnb, fb := f.nb, f.b
+
 	switch f.stepState {
 	case stateInit:
 		goto readLiteral
@@ -39,41 +44,35 @@ readLiteral:
 			// cases, the chunks slice will be 0 for the invalid sequence, leading it
 			// satisfy the n == 0 check below.
 			n := uint(f.hl.maxRead)
-			// Optimization. Compiler isn't smart enough to keep f.b,f.nb in registers,
-			// but is smart enough to keep local variables in registers, so use nb and b,
-			// inline call to moreBits and reassign b,nb back to f on return.
-			nb, b := f.nb, f.b
 			for {
-				for nb < n {
+				for fnb < n {
 					c, err := fr.ReadByte()
 					if err != nil {
-						f.b = b
-						f.nb = nb
+						f.b, f.nb = fb, fnb
 						f.err = noEOF(err)
 						return
 					}
 					f.roffset++
-					b |= uint32(c) << (nb & regSizeMaskUint32)
-					nb += 8
+					fb |= uint32(c) << (fnb & regSizeMaskUint32)
+					fnb += 8
 				}
-				chunk := f.hl.chunks[b&(huffmanNumChunks-1)]
+				chunk := f.hl.chunks[fb&(huffmanNumChunks-1)]
 				n = uint(chunk & huffmanCountMask)
 				if n > huffmanChunkBits {
-					chunk = f.hl.links[chunk>>huffmanValueShift][(b>>huffmanChunkBits)&f.hl.linkMask]
+					chunk = f.hl.links[chunk>>huffmanValueShift][(fb>>huffmanChunkBits)&f.hl.linkMask]
 					n = uint(chunk & huffmanCountMask)
 				}
-				if n <= nb {
+				if n <= fnb {
 					if n == 0 {
-						f.b = b
-						f.nb = nb
+						f.b, f.nb = fb, fnb
 						if debugDecode {
 							fmt.Println("huffsym: n==0")
 						}
 						f.err = CorruptInputError(f.roffset)
 						return
 					}
-					f.b = b >> (n & regSizeMaskUint32)
-					f.nb = nb - n
+					fb = fb >> (n & regSizeMaskUint32)
+					fnb = fnb - n
 					v = int(chunk >> huffmanValueShift)
 					break
 				}
@@ -88,10 +87,12 @@ readLiteral:
 				f.toRead = f.dict.readFlush()
 				f.step = (*decompressor).huffmanBytesBuffer
 				f.stepState = stateInit
+				f.b, f.nb = fb, fnb
 				return
 			}
 			goto readLiteral
 		case v == 256:
+			f.b, f.nb = fb, fnb
 			f.finishBlock()
 			return
 		// otherwise, reference to older data
@@ -101,9 +102,10 @@ readLiteral:
 			val := decCodeToLen[(v - 257)]
 			length = int(val.length) + 3
 			n := uint(val.extra)
-			for f.nb < n {
+			for fnb < n {
 				c, err := fr.ReadByte()
 				if err != nil {
+					f.b, f.nb = fb, fnb
 					if debugDecode {
 						fmt.Println("morebits n>0:", err)
 					}
@@ -111,25 +113,27 @@ readLiteral:
 					return
 				}
 				f.roffset++
-				f.b |= uint32(c) << f.nb
-				f.nb += 8
+				fb |= uint32(c) << (fnb & regSizeMaskUint32)
+				fnb += 8
 			}
-			length += int(f.b & uint32(1<<(n&regSizeMaskUint32)-1))
-			f.b >>= n & regSizeMaskUint32
-			f.nb -= n
+			length += int(fb & bitMask32[n])
+			fb >>= n & regSizeMaskUint32
+			fnb -= n
 		default:
 			if debugDecode {
 				fmt.Println(v, ">= maxNumLit")
 			}
 			f.err = CorruptInputError(f.roffset)
+			f.b, f.nb = fb, fnb
 			return
 		}
 
 		var dist uint32
 		if f.hd == nil {
-			for f.nb < 5 {
+			for fnb < 5 {
 				c, err := fr.ReadByte()
 				if err != nil {
+					f.b, f.nb = fb, fnb
 					if debugDecode {
 						fmt.Println("morebits f.nb<5:", err)
 					}
@@ -137,12 +141,12 @@ readLiteral:
 					return
 				}
 				f.roffset++
-				f.b |= uint32(c) << f.nb
-				f.nb += 8
+				fb |= uint32(c) << (fnb & regSizeMaskUint32)
+				fnb += 8
 			}
-			dist = uint32(bits.Reverse8(uint8(f.b & 0x1F << 3)))
-			f.b >>= 5
-			f.nb -= 5
+			dist = uint32(bits.Reverse8(uint8(fb & 0x1F << 3)))
+			fb >>= 5
+			fnb -= 5
 		} else {
 			// Since a huffmanDecoder can be empty or be composed of a degenerate tree
 			// with single element, huffSym must error on these two edge cases. In both
@@ -152,38 +156,35 @@ readLiteral:
 			// Optimization. Compiler isn't smart enough to keep f.b,f.nb in registers,
 			// but is smart enough to keep local variables in registers, so use nb and b,
 			// inline call to moreBits and reassign b,nb back to f on return.
-			nb, b := f.nb, f.b
 			for {
-				for nb < n {
+				for fnb < n {
 					c, err := fr.ReadByte()
 					if err != nil {
-						f.b = b
-						f.nb = nb
+						f.b, f.nb = fb, fnb
 						f.err = noEOF(err)
 						return
 					}
 					f.roffset++
-					b |= uint32(c) << (nb & regSizeMaskUint32)
-					nb += 8
+					fb |= uint32(c) << (fnb & regSizeMaskUint32)
+					fnb += 8
 				}
-				chunk := f.hd.chunks[b&(huffmanNumChunks-1)]
+				chunk := f.hd.chunks[fb&(huffmanNumChunks-1)]
 				n = uint(chunk & huffmanCountMask)
 				if n > huffmanChunkBits {
-					chunk = f.hd.links[chunk>>huffmanValueShift][(b>>huffmanChunkBits)&f.hd.linkMask]
+					chunk = f.hd.links[chunk>>huffmanValueShift][(fb>>huffmanChunkBits)&f.hd.linkMask]
 					n = uint(chunk & huffmanCountMask)
 				}
-				if n <= nb {
+				if n <= fnb {
 					if n == 0 {
-						f.b = b
-						f.nb = nb
+						f.b, f.nb = fb, fnb
 						if debugDecode {
 							fmt.Println("huffsym: n==0")
 						}
 						f.err = CorruptInputError(f.roffset)
 						return
 					}
-					f.b = b >> (n & regSizeMaskUint32)
-					f.nb = nb - n
+					fb = fb >> (n & regSizeMaskUint32)
+					fnb = fnb - n
 					dist = uint32(chunk >> huffmanValueShift)
 					break
 				}
@@ -197,9 +198,10 @@ readLiteral:
 			nb := uint(dist-2) >> 1
 			// have 1 bit in bottom of dist, need nb more.
 			extra := (dist & 1) << (nb & regSizeMaskUint32)
-			for f.nb < nb {
+			for fnb < nb {
 				c, err := fr.ReadByte()
 				if err != nil {
+					f.b, f.nb = fb, fnb
 					if debugDecode {
 						fmt.Println("morebits f.nb<nb:", err)
 					}
@@ -207,14 +209,16 @@ readLiteral:
 					return
 				}
 				f.roffset++
-				f.b |= uint32(c) << f.nb
-				f.nb += 8
+				fb |= uint32(c) << (fnb & regSizeMaskUint32)
+				fnb += 8
 			}
-			extra |= f.b & uint32(1<<(nb&regSizeMaskUint32)-1)
-			f.b >>= nb & regSizeMaskUint32
-			f.nb -= nb
+			extra |= fb & bitMask32[nb]
+			fb >>= nb & regSizeMaskUint32
+			fnb -= nb
 			dist = 1<<((nb+1)&regSizeMaskUint32) + 1 + extra
+			// slower: dist = bitMask32[nb+1] + 2 + extra
 		default:
+			f.b, f.nb = fb, fnb
 			if debugDecode {
 				fmt.Println("dist too big:", dist, maxNumDist)
 			}
@@ -224,6 +228,7 @@ readLiteral:
 
 		// No check on length; encoding can be prescient.
 		if dist > uint32(f.dict.histSize()) {
+			f.b, f.nb = fb, fnb
 			if debugDecode {
 				fmt.Println("dist > f.dict.histSize():", dist, f.dict.histSize())
 			}
@@ -248,10 +253,12 @@ copyHistory:
 			f.toRead = f.dict.readFlush()
 			f.step = (*decompressor).huffmanBytesBuffer // We need to continue this work
 			f.stepState = stateDict
+			f.b, f.nb = fb, fnb
 			return
 		}
 		goto readLiteral
 	}
+	// Not reached
 }
 
 // Decode a single Huffman block from f.
@@ -265,6 +272,11 @@ func (f *decompressor) huffmanBytesReader() {
 	)
 	fr := f.r.(*bytes.Reader)
 
+	// Optimization. Compiler isn't smart enough to keep f.b,f.nb in registers,
+	// but is smart enough to keep local variables in registers, so use nb and b,
+	// inline call to moreBits and reassign b,nb back to f on return.
+	fnb, fb := f.nb, f.b
+
 	switch f.stepState {
 	case stateInit:
 		goto readLiteral
@@ -283,41 +295,35 @@ readLiteral:
 			// cases, the chunks slice will be 0 for the invalid sequence, leading it
 			// satisfy the n == 0 check below.
 			n := uint(f.hl.maxRead)
-			// Optimization. Compiler isn't smart enough to keep f.b,f.nb in registers,
-			// but is smart enough to keep local variables in registers, so use nb and b,
-			// inline call to moreBits and reassign b,nb back to f on return.
-			nb, b := f.nb, f.b
 			for {
-				for nb < n {
+				for fnb < n {
 					c, err := fr.ReadByte()
 					if err != nil {
-						f.b = b
-						f.nb = nb
+						f.b, f.nb = fb, fnb
 						f.err = noEOF(err)
 						return
 					}
 					f.roffset++
-					b |= uint32(c) << (nb & regSizeMaskUint32)
-					nb += 8
+					fb |= uint32(c) << (fnb & regSizeMaskUint32)
+					fnb += 8
 				}
-				chunk := f.hl.chunks[b&(huffmanNumChunks-1)]
+				chunk := f.hl.chunks[fb&(huffmanNumChunks-1)]
 				n = uint(chunk & huffmanCountMask)
 				if n > huffmanChunkBits {
-					chunk = f.hl.links[chunk>>huffmanValueShift][(b>>huffmanChunkBits)&f.hl.linkMask]
+					chunk = f.hl.links[chunk>>huffmanValueShift][(fb>>huffmanChunkBits)&f.hl.linkMask]
 					n = uint(chunk & huffmanCountMask)
 				}
-				if n <= nb {
+				if n <= fnb {
 					if n == 0 {
-						f.b = b
-						f.nb = nb
+						f.b, f.nb = fb, fnb
 						if debugDecode {
 							fmt.Println("huffsym: n==0")
 						}
 						f.err = CorruptInputError(f.roffset)
 						return
 					}
-					f.b = b >> (n & regSizeMaskUint32)
-					f.nb = nb - n
+					fb = fb >> (n & regSizeMaskUint32)
+					fnb = fnb - n
 					v = int(chunk >> huffmanValueShift)
 					break
 				}
@@ -332,10 +338,12 @@ readLiteral:
 				f.toRead = f.dict.readFlush()
 				f.step = (*decompressor).huffmanBytesReader
 				f.stepState = stateInit
+				f.b, f.nb = fb, fnb
 				return
 			}
 			goto readLiteral
 		case v == 256:
+			f.b, f.nb = fb, fnb
 			f.finishBlock()
 			return
 		// otherwise, reference to older data
@@ -345,9 +353,10 @@ readLiteral:
 			val := decCodeToLen[(v - 257)]
 			length = int(val.length) + 3
 			n := uint(val.extra)
-			for f.nb < n {
+			for fnb < n {
 				c, err := fr.ReadByte()
 				if err != nil {
+					f.b, f.nb = fb, fnb
 					if debugDecode {
 						fmt.Println("morebits n>0:", err)
 					}
@@ -355,25 +364,27 @@ readLiteral:
 					return
 				}
 				f.roffset++
-				f.b |= uint32(c) << f.nb
-				f.nb += 8
+				fb |= uint32(c) << (fnb & regSizeMaskUint32)
+				fnb += 8
 			}
-			length += int(f.b & uint32(1<<(n&regSizeMaskUint32)-1))
-			f.b >>= n & regSizeMaskUint32
-			f.nb -= n
+			length += int(fb & bitMask32[n])
+			fb >>= n & regSizeMaskUint32
+			fnb -= n
 		default:
 			if debugDecode {
 				fmt.Println(v, ">= maxNumLit")
 			}
 			f.err = CorruptInputError(f.roffset)
+			f.b, f.nb = fb, fnb
 			return
 		}
 
 		var dist uint32
 		if f.hd == nil {
-			for f.nb < 5 {
+			for fnb < 5 {
 				c, err := fr.ReadByte()
 				if err != nil {
+					f.b, f.nb = fb, fnb
 					if debugDecode {
 						fmt.Println("morebits f.nb<5:", err)
 					}
@@ -381,12 +392,12 @@ readLiteral:
 					return
 				}
 				f.roffset++
-				f.b |= uint32(c) << f.nb
-				f.nb += 8
+				fb |= uint32(c) << (fnb & regSizeMaskUint32)
+				fnb += 8
 			}
-			dist = uint32(bits.Reverse8(uint8(f.b & 0x1F << 3)))
-			f.b >>= 5
-			f.nb -= 5
+			dist = uint32(bits.Reverse8(uint8(fb & 0x1F << 3)))
+			fb >>= 5
+			fnb -= 5
 		} else {
 			// Since a huffmanDecoder can be empty or be composed of a degenerate tree
 			// with single element, huffSym must error on these two edge cases. In both
@@ -396,38 +407,35 @@ readLiteral:
 			// Optimization. Compiler isn't smart enough to keep f.b,f.nb in registers,
 			// but is smart enough to keep local variables in registers, so use nb and b,
 			// inline call to moreBits and reassign b,nb back to f on return.
-			nb, b := f.nb, f.b
 			for {
-				for nb < n {
+				for fnb < n {
 					c, err := fr.ReadByte()
 					if err != nil {
-						f.b = b
-						f.nb = nb
+						f.b, f.nb = fb, fnb
 						f.err = noEOF(err)
 						return
 					}
 					f.roffset++
-					b |= uint32(c) << (nb & regSizeMaskUint32)
-					nb += 8
+					fb |= uint32(c) << (fnb & regSizeMaskUint32)
+					fnb += 8
 				}
-				chunk := f.hd.chunks[b&(huffmanNumChunks-1)]
+				chunk := f.hd.chunks[fb&(huffmanNumChunks-1)]
 				n = uint(chunk & huffmanCountMask)
 				if n > huffmanChunkBits {
-					chunk = f.hd.links[chunk>>huffmanValueShift][(b>>huffmanChunkBits)&f.hd.linkMask]
+					chunk = f.hd.links[chunk>>huffmanValueShift][(fb>>huffmanChunkBits)&f.hd.linkMask]
 					n = uint(chunk & huffmanCountMask)
 				}
-				if n <= nb {
+				if n <= fnb {
 					if n == 0 {
-						f.b = b
-						f.nb = nb
+						f.b, f.nb = fb, fnb
 						if debugDecode {
 							fmt.Println("huffsym: n==0")
 						}
 						f.err = CorruptInputError(f.roffset)
 						return
 					}
-					f.b = b >> (n & regSizeMaskUint32)
-					f.nb = nb - n
+					fb = fb >> (n & regSizeMaskUint32)
+					fnb = fnb - n
 					dist = uint32(chunk >> huffmanValueShift)
 					break
 				}
@@ -441,9 +449,10 @@ readLiteral:
 			nb := uint(dist-2) >> 1
 			// have 1 bit in bottom of dist, need nb more.
 			extra := (dist & 1) << (nb & regSizeMaskUint32)
-			for f.nb < nb {
+			for fnb < nb {
 				c, err := fr.ReadByte()
 				if err != nil {
+					f.b, f.nb = fb, fnb
 					if debugDecode {
 						fmt.Println("morebits f.nb<nb:", err)
 					}
@@ -451,14 +460,16 @@ readLiteral:
 					return
 				}
 				f.roffset++
-				f.b |= uint32(c) << f.nb
-				f.nb += 8
+				fb |= uint32(c) << (fnb & regSizeMaskUint32)
+				fnb += 8
 			}
-			extra |= f.b & uint32(1<<(nb&regSizeMaskUint32)-1)
-			f.b >>= nb & regSizeMaskUint32
-			f.nb -= nb
+			extra |= fb & bitMask32[nb]
+			fb >>= nb & regSizeMaskUint32
+			fnb -= nb
 			dist = 1<<((nb+1)&regSizeMaskUint32) + 1 + extra
+			// slower: dist = bitMask32[nb+1] + 2 + extra
 		default:
+			f.b, f.nb = fb, fnb
 			if debugDecode {
 				fmt.Println("dist too big:", dist, maxNumDist)
 			}
@@ -468,6 +479,7 @@ readLiteral:
 
 		// No check on length; encoding can be prescient.
 		if dist > uint32(f.dict.histSize()) {
+			f.b, f.nb = fb, fnb
 			if debugDecode {
 				fmt.Println("dist > f.dict.histSize():", dist, f.dict.histSize())
 			}
@@ -492,10 +504,12 @@ copyHistory:
 			f.toRead = f.dict.readFlush()
 			f.step = (*decompressor).huffmanBytesReader // We need to continue this work
 			f.stepState = stateDict
+			f.b, f.nb = fb, fnb
 			return
 		}
 		goto readLiteral
 	}
+	// Not reached
 }
 
 // Decode a single Huffman block from f.
@@ -509,6 +523,11 @@ func (f *decompressor) huffmanBufioReader() {
 	)
 	fr := f.r.(*bufio.Reader)
 
+	// Optimization. Compiler isn't smart enough to keep f.b,f.nb in registers,
+	// but is smart enough to keep local variables in registers, so use nb and b,
+	// inline call to moreBits and reassign b,nb back to f on return.
+	fnb, fb := f.nb, f.b
+
 	switch f.stepState {
 	case stateInit:
 		goto readLiteral
@@ -527,41 +546,35 @@ readLiteral:
 			// cases, the chunks slice will be 0 for the invalid sequence, leading it
 			// satisfy the n == 0 check below.
 			n := uint(f.hl.maxRead)
-			// Optimization. Compiler isn't smart enough to keep f.b,f.nb in registers,
-			// but is smart enough to keep local variables in registers, so use nb and b,
-			// inline call to moreBits and reassign b,nb back to f on return.
-			nb, b := f.nb, f.b
 			for {
-				for nb < n {
+				for fnb < n {
 					c, err := fr.ReadByte()
 					if err != nil {
-						f.b = b
-						f.nb = nb
+						f.b, f.nb = fb, fnb
 						f.err = noEOF(err)
 						return
 					}
 					f.roffset++
-					b |= uint32(c) << (nb & regSizeMaskUint32)
-					nb += 8
+					fb |= uint32(c) << (fnb & regSizeMaskUint32)
+					fnb += 8
 				}
-				chunk := f.hl.chunks[b&(huffmanNumChunks-1)]
+				chunk := f.hl.chunks[fb&(huffmanNumChunks-1)]
 				n = uint(chunk & huffmanCountMask)
 				if n > huffmanChunkBits {
-					chunk = f.hl.links[chunk>>huffmanValueShift][(b>>huffmanChunkBits)&f.hl.linkMask]
+					chunk = f.hl.links[chunk>>huffmanValueShift][(fb>>huffmanChunkBits)&f.hl.linkMask]
 					n = uint(chunk & huffmanCountMask)
 				}
-				if n <= nb {
+				if n <= fnb {
 					if n == 0 {
-						f.b = b
-						f.nb = nb
+						f.b, f.nb = fb, fnb
 						if debugDecode {
 							fmt.Println("huffsym: n==0")
 						}
 						f.err = CorruptInputError(f.roffset)
 						return
 					}
-					f.b = b >> (n & regSizeMaskUint32)
-					f.nb = nb - n
+					fb = fb >> (n & regSizeMaskUint32)
+					fnb = fnb - n
 					v = int(chunk >> huffmanValueShift)
 					break
 				}
@@ -576,10 +589,12 @@ readLiteral:
 				f.toRead = f.dict.readFlush()
 				f.step = (*decompressor).huffmanBufioReader
 				f.stepState = stateInit
+				f.b, f.nb = fb, fnb
 				return
 			}
 			goto readLiteral
 		case v == 256:
+			f.b, f.nb = fb, fnb
 			f.finishBlock()
 			return
 		// otherwise, reference to older data
@@ -589,9 +604,10 @@ readLiteral:
 			val := decCodeToLen[(v - 257)]
 			length = int(val.length) + 3
 			n := uint(val.extra)
-			for f.nb < n {
+			for fnb < n {
 				c, err := fr.ReadByte()
 				if err != nil {
+					f.b, f.nb = fb, fnb
 					if debugDecode {
 						fmt.Println("morebits n>0:", err)
 					}
@@ -599,25 +615,27 @@ readLiteral:
 					return
 				}
 				f.roffset++
-				f.b |= uint32(c) << f.nb
-				f.nb += 8
+				fb |= uint32(c) << (fnb & regSizeMaskUint32)
+				fnb += 8
 			}
-			length += int(f.b & uint32(1<<(n&regSizeMaskUint32)-1))
-			f.b >>= n & regSizeMaskUint32
-			f.nb -= n
+			length += int(fb & bitMask32[n])
+			fb >>= n & regSizeMaskUint32
+			fnb -= n
 		default:
 			if debugDecode {
 				fmt.Println(v, ">= maxNumLit")
 			}
 			f.err = CorruptInputError(f.roffset)
+			f.b, f.nb = fb, fnb
 			return
 		}
 
 		var dist uint32
 		if f.hd == nil {
-			for f.nb < 5 {
+			for fnb < 5 {
 				c, err := fr.ReadByte()
 				if err != nil {
+					f.b, f.nb = fb, fnb
 					if debugDecode {
 						fmt.Println("morebits f.nb<5:", err)
 					}
@@ -625,12 +643,12 @@ readLiteral:
 					return
 				}
 				f.roffset++
-				f.b |= uint32(c) << f.nb
-				f.nb += 8
+				fb |= uint32(c) << (fnb & regSizeMaskUint32)
+				fnb += 8
 			}
-			dist = uint32(bits.Reverse8(uint8(f.b & 0x1F << 3)))
-			f.b >>= 5
-			f.nb -= 5
+			dist = uint32(bits.Reverse8(uint8(fb & 0x1F << 3)))
+			fb >>= 5
+			fnb -= 5
 		} else {
 			// Since a huffmanDecoder can be empty or be composed of a degenerate tree
 			// with single element, huffSym must error on these two edge cases. In both
@@ -640,38 +658,35 @@ readLiteral:
 			// Optimization. Compiler isn't smart enough to keep f.b,f.nb in registers,
 			// but is smart enough to keep local variables in registers, so use nb and b,
 			// inline call to moreBits and reassign b,nb back to f on return.
-			nb, b := f.nb, f.b
 			for {
-				for nb < n {
+				for fnb < n {
 					c, err := fr.ReadByte()
 					if err != nil {
-						f.b = b
-						f.nb = nb
+						f.b, f.nb = fb, fnb
 						f.err = noEOF(err)
 						return
 					}
 					f.roffset++
-					b |= uint32(c) << (nb & regSizeMaskUint32)
-					nb += 8
+					fb |= uint32(c) << (fnb & regSizeMaskUint32)
+					fnb += 8
 				}
-				chunk := f.hd.chunks[b&(huffmanNumChunks-1)]
+				chunk := f.hd.chunks[fb&(huffmanNumChunks-1)]
 				n = uint(chunk & huffmanCountMask)
 				if n > huffmanChunkBits {
-					chunk = f.hd.links[chunk>>huffmanValueShift][(b>>huffmanChunkBits)&f.hd.linkMask]
+					chunk = f.hd.links[chunk>>huffmanValueShift][(fb>>huffmanChunkBits)&f.hd.linkMask]
 					n = uint(chunk & huffmanCountMask)
 				}
-				if n <= nb {
+				if n <= fnb {
 					if n == 0 {
-						f.b = b
-						f.nb = nb
+						f.b, f.nb = fb, fnb
 						if debugDecode {
 							fmt.Println("huffsym: n==0")
 						}
 						f.err = CorruptInputError(f.roffset)
 						return
 					}
-					f.b = b >> (n & regSizeMaskUint32)
-					f.nb = nb - n
+					fb = fb >> (n & regSizeMaskUint32)
+					fnb = fnb - n
 					dist = uint32(chunk >> huffmanValueShift)
 					break
 				}
@@ -685,9 +700,10 @@ readLiteral:
 			nb := uint(dist-2) >> 1
 			// have 1 bit in bottom of dist, need nb more.
 			extra := (dist & 1) << (nb & regSizeMaskUint32)
-			for f.nb < nb {
+			for fnb < nb {
 				c, err := fr.ReadByte()
 				if err != nil {
+					f.b, f.nb = fb, fnb
 					if debugDecode {
 						fmt.Println("morebits f.nb<nb:", err)
 					}
@@ -695,14 +711,16 @@ readLiteral:
 					return
 				}
 				f.roffset++
-				f.b |= uint32(c) << f.nb
-				f.nb += 8
+				fb |= uint32(c) << (fnb & regSizeMaskUint32)
+				fnb += 8
 			}
-			extra |= f.b & uint32(1<<(nb&regSizeMaskUint32)-1)
-			f.b >>= nb & regSizeMaskUint32
-			f.nb -= nb
+			extra |= fb & bitMask32[nb]
+			fb >>= nb & regSizeMaskUint32
+			fnb -= nb
 			dist = 1<<((nb+1)&regSizeMaskUint32) + 1 + extra
+			// slower: dist = bitMask32[nb+1] + 2 + extra
 		default:
+			f.b, f.nb = fb, fnb
 			if debugDecode {
 				fmt.Println("dist too big:", dist, maxNumDist)
 			}
@@ -712,6 +730,7 @@ readLiteral:
 
 		// No check on length; encoding can be prescient.
 		if dist > uint32(f.dict.histSize()) {
+			f.b, f.nb = fb, fnb
 			if debugDecode {
 				fmt.Println("dist > f.dict.histSize():", dist, f.dict.histSize())
 			}
@@ -736,10 +755,12 @@ copyHistory:
 			f.toRead = f.dict.readFlush()
 			f.step = (*decompressor).huffmanBufioReader // We need to continue this work
 			f.stepState = stateDict
+			f.b, f.nb = fb, fnb
 			return
 		}
 		goto readLiteral
 	}
+	// Not reached
 }
 
 // Decode a single Huffman block from f.
@@ -753,6 +774,11 @@ func (f *decompressor) huffmanStringsReader() {
 	)
 	fr := f.r.(*strings.Reader)
 
+	// Optimization. Compiler isn't smart enough to keep f.b,f.nb in registers,
+	// but is smart enough to keep local variables in registers, so use nb and b,
+	// inline call to moreBits and reassign b,nb back to f on return.
+	fnb, fb := f.nb, f.b
+
 	switch f.stepState {
 	case stateInit:
 		goto readLiteral
@@ -771,41 +797,286 @@ readLiteral:
 			// cases, the chunks slice will be 0 for the invalid sequence, leading it
 			// satisfy the n == 0 check below.
 			n := uint(f.hl.maxRead)
+			for {
+				for fnb < n {
+					c, err := fr.ReadByte()
+					if err != nil {
+						f.b, f.nb = fb, fnb
+						f.err = noEOF(err)
+						return
+					}
+					f.roffset++
+					fb |= uint32(c) << (fnb & regSizeMaskUint32)
+					fnb += 8
+				}
+				chunk := f.hl.chunks[fb&(huffmanNumChunks-1)]
+				n = uint(chunk & huffmanCountMask)
+				if n > huffmanChunkBits {
+					chunk = f.hl.links[chunk>>huffmanValueShift][(fb>>huffmanChunkBits)&f.hl.linkMask]
+					n = uint(chunk & huffmanCountMask)
+				}
+				if n <= fnb {
+					if n == 0 {
+						f.b, f.nb = fb, fnb
+						if debugDecode {
+							fmt.Println("huffsym: n==0")
+						}
+						f.err = CorruptInputError(f.roffset)
+						return
+					}
+					fb = fb >> (n & regSizeMaskUint32)
+					fnb = fnb - n
+					v = int(chunk >> huffmanValueShift)
+					break
+				}
+			}
+		}
+
+		var length int
+		switch {
+		case v < 256:
+			f.dict.writeByte(byte(v))
+			if f.dict.availWrite() == 0 {
+				f.toRead = f.dict.readFlush()
+				f.step = (*decompressor).huffmanStringsReader
+				f.stepState = stateInit
+				f.b, f.nb = fb, fnb
+				return
+			}
+			goto readLiteral
+		case v == 256:
+			f.b, f.nb = fb, fnb
+			f.finishBlock()
+			return
+		// otherwise, reference to older data
+		case v < 265:
+			length = v - (257 - 3)
+		case v < maxNumLit:
+			val := decCodeToLen[(v - 257)]
+			length = int(val.length) + 3
+			n := uint(val.extra)
+			for fnb < n {
+				c, err := fr.ReadByte()
+				if err != nil {
+					f.b, f.nb = fb, fnb
+					if debugDecode {
+						fmt.Println("morebits n>0:", err)
+					}
+					f.err = err
+					return
+				}
+				f.roffset++
+				fb |= uint32(c) << (fnb & regSizeMaskUint32)
+				fnb += 8
+			}
+			length += int(fb & bitMask32[n])
+			fb >>= n & regSizeMaskUint32
+			fnb -= n
+		default:
+			if debugDecode {
+				fmt.Println(v, ">= maxNumLit")
+			}
+			f.err = CorruptInputError(f.roffset)
+			f.b, f.nb = fb, fnb
+			return
+		}
+
+		var dist uint32
+		if f.hd == nil {
+			for fnb < 5 {
+				c, err := fr.ReadByte()
+				if err != nil {
+					f.b, f.nb = fb, fnb
+					if debugDecode {
+						fmt.Println("morebits f.nb<5:", err)
+					}
+					f.err = err
+					return
+				}
+				f.roffset++
+				fb |= uint32(c) << (fnb & regSizeMaskUint32)
+				fnb += 8
+			}
+			dist = uint32(bits.Reverse8(uint8(fb & 0x1F << 3)))
+			fb >>= 5
+			fnb -= 5
+		} else {
+			// Since a huffmanDecoder can be empty or be composed of a degenerate tree
+			// with single element, huffSym must error on these two edge cases. In both
+			// cases, the chunks slice will be 0 for the invalid sequence, leading it
+			// satisfy the n == 0 check below.
+			n := uint(f.hd.maxRead)
 			// Optimization. Compiler isn't smart enough to keep f.b,f.nb in registers,
 			// but is smart enough to keep local variables in registers, so use nb and b,
 			// inline call to moreBits and reassign b,nb back to f on return.
-			nb, b := f.nb, f.b
 			for {
-				for nb < n {
+				for fnb < n {
+					c, err := fr.ReadByte()
+					if err != nil {
+						f.b, f.nb = fb, fnb
+						f.err = noEOF(err)
+						return
+					}
+					f.roffset++
+					fb |= uint32(c) << (fnb & regSizeMaskUint32)
+					fnb += 8
+				}
+				chunk := f.hd.chunks[fb&(huffmanNumChunks-1)]
+				n = uint(chunk & huffmanCountMask)
+				if n > huffmanChunkBits {
+					chunk = f.hd.links[chunk>>huffmanValueShift][(fb>>huffmanChunkBits)&f.hd.linkMask]
+					n = uint(chunk & huffmanCountMask)
+				}
+				if n <= fnb {
+					if n == 0 {
+						f.b, f.nb = fb, fnb
+						if debugDecode {
+							fmt.Println("huffsym: n==0")
+						}
+						f.err = CorruptInputError(f.roffset)
+						return
+					}
+					fb = fb >> (n & regSizeMaskUint32)
+					fnb = fnb - n
+					dist = uint32(chunk >> huffmanValueShift)
+					break
+				}
+			}
+		}
+
+		switch {
+		case dist < 4:
+			dist++
+		case dist < maxNumDist:
+			nb := uint(dist-2) >> 1
+			// have 1 bit in bottom of dist, need nb more.
+			extra := (dist & 1) << (nb & regSizeMaskUint32)
+			for fnb < nb {
+				c, err := fr.ReadByte()
+				if err != nil {
+					f.b, f.nb = fb, fnb
+					if debugDecode {
+						fmt.Println("morebits f.nb<nb:", err)
+					}
+					f.err = err
+					return
+				}
+				f.roffset++
+				fb |= uint32(c) << (fnb & regSizeMaskUint32)
+				fnb += 8
+			}
+			extra |= fb & bitMask32[nb]
+			fb >>= nb & regSizeMaskUint32
+			fnb -= nb
+			dist = 1<<((nb+1)&regSizeMaskUint32) + 1 + extra
+			// slower: dist = bitMask32[nb+1] + 2 + extra
+		default:
+			f.b, f.nb = fb, fnb
+			if debugDecode {
+				fmt.Println("dist too big:", dist, maxNumDist)
+			}
+			f.err = CorruptInputError(f.roffset)
+			return
+		}
+
+		// No check on length; encoding can be prescient.
+		if dist > uint32(f.dict.histSize()) {
+			f.b, f.nb = fb, fnb
+			if debugDecode {
+				fmt.Println("dist > f.dict.histSize():", dist, f.dict.histSize())
+			}
+			f.err = CorruptInputError(f.roffset)
+			return
+		}
+
+		f.copyLen, f.copyDist = length, int(dist)
+		goto copyHistory
+	}
+
+copyHistory:
+	// Perform a backwards copy according to RFC section 3.2.3.
+	{
+		cnt := f.dict.tryWriteCopy(f.copyDist, f.copyLen)
+		if cnt == 0 {
+			cnt = f.dict.writeCopy(f.copyDist, f.copyLen)
+		}
+		f.copyLen -= cnt
+
+		if f.dict.availWrite() == 0 || f.copyLen > 0 {
+			f.toRead = f.dict.readFlush()
+			f.step = (*decompressor).huffmanStringsReader // We need to continue this work
+			f.stepState = stateDict
+			f.b, f.nb = fb, fnb
+			return
+		}
+		goto readLiteral
+	}
+	// Not reached
+}
+
+// Decode a single Huffman block from f.
+// hl and hd are the Huffman states for the lit/length values
+// and the distance values, respectively. If hd == nil, using the
+// fixed distance encoding associated with fixed Huffman blocks.
+func (f *decompressor) huffmanGenericReader() {
+	const (
+		stateInit = iota // Zero value must be stateInit
+		stateDict
+	)
+	fr := f.r.(Reader)
+
+	// Optimization. Compiler isn't smart enough to keep f.b,f.nb in registers,
+	// but is smart enough to keep local variables in registers, so use nb and b,
+	// inline call to moreBits and reassign b,nb back to f on return.
+	fnb, fb := f.nb, f.b
+
+	switch f.stepState {
+	case stateInit:
+		goto readLiteral
+	case stateDict:
+		goto copyHistory
+	}
+
+readLiteral:
+	// Read literal and/or (length, distance) according to RFC section 3.2.3.
+	{
+		var v int
+		{
+			// Inlined v, err := f.huffSym(f.hl)
+			// Since a huffmanDecoder can be empty or be composed of a degenerate tree
+			// with single element, huffSym must error on these two edge cases. In both
+			// cases, the chunks slice will be 0 for the invalid sequence, leading it
+			// satisfy the n == 0 check below.
+			n := uint(f.hl.maxRead)
+			for {
+				for fnb < n {
 					c, err := fr.ReadByte()
 					if err != nil {
-						f.b = b
-						f.nb = nb
+						f.b, f.nb = fb, fnb
 						f.err = noEOF(err)
 						return
 					}
 					f.roffset++
-					b |= uint32(c) << (nb & regSizeMaskUint32)
-					nb += 8
+					fb |= uint32(c) << (fnb & regSizeMaskUint32)
+					fnb += 8
 				}
-				chunk := f.hl.chunks[b&(huffmanNumChunks-1)]
+				chunk := f.hl.chunks[fb&(huffmanNumChunks-1)]
 				n = uint(chunk & huffmanCountMask)
 				if n > huffmanChunkBits {
-					chunk = f.hl.links[chunk>>huffmanValueShift][(b>>huffmanChunkBits)&f.hl.linkMask]
+					chunk = f.hl.links[chunk>>huffmanValueShift][(fb>>huffmanChunkBits)&f.hl.linkMask]
 					n = uint(chunk & huffmanCountMask)
 				}
-				if n <= nb {
+				if n <= fnb {
 					if n == 0 {
-						f.b = b
-						f.nb = nb
+						f.b, f.nb = fb, fnb
 						if debugDecode {
 							fmt.Println("huffsym: n==0")
 						}
 						f.err = CorruptInputError(f.roffset)
 						return
 					}
-					f.b = b >> (n & regSizeMaskUint32)
-					f.nb = nb - n
+					fb = fb >> (n & regSizeMaskUint32)
+					fnb = fnb - n
 					v = int(chunk >> huffmanValueShift)
 					break
 				}
@@ -818,12 +1089,14 @@ readLiteral:
 			f.dict.writeByte(byte(v))
 			if f.dict.availWrite() == 0 {
 				f.toRead = f.dict.readFlush()
-				f.step = (*decompressor).huffmanStringsReader
+				f.step = (*decompressor).huffmanGenericReader
 				f.stepState = stateInit
+				f.b, f.nb = fb, fnb
 				return
 			}
 			goto readLiteral
 		case v == 256:
+			f.b, f.nb = fb, fnb
 			f.finishBlock()
 			return
 		// otherwise, reference to older data
@@ -833,9 +1106,10 @@ readLiteral:
 			val := decCodeToLen[(v - 257)]
 			length = int(val.length) + 3
 			n := uint(val.extra)
-			for f.nb < n {
+			for fnb < n {
 				c, err := fr.ReadByte()
 				if err != nil {
+					f.b, f.nb = fb, fnb
 					if debugDecode {
 						fmt.Println("morebits n>0:", err)
 					}
@@ -843,25 +1117,27 @@ readLiteral:
 					return
 				}
 				f.roffset++
-				f.b |= uint32(c) << f.nb
-				f.nb += 8
+				fb |= uint32(c) << (fnb & regSizeMaskUint32)
+				fnb += 8
 			}
-			length += int(f.b & uint32(1<<(n&regSizeMaskUint32)-1))
-			f.b >>= n & regSizeMaskUint32
-			f.nb -= n
+			length += int(fb & bitMask32[n])
+			fb >>= n & regSizeMaskUint32
+			fnb -= n
 		default:
 			if debugDecode {
 				fmt.Println(v, ">= maxNumLit")
 			}
 			f.err = CorruptInputError(f.roffset)
+			f.b, f.nb = fb, fnb
 			return
 		}
 
 		var dist uint32
 		if f.hd == nil {
-			for f.nb < 5 {
+			for fnb < 5 {
 				c, err := fr.ReadByte()
 				if err != nil {
+					f.b, f.nb = fb, fnb
 					if debugDecode {
 						fmt.Println("morebits f.nb<5:", err)
 					}
@@ -869,12 +1145,12 @@ readLiteral:
 					return
 				}
 				f.roffset++
-				f.b |= uint32(c) << f.nb
-				f.nb += 8
+				fb |= uint32(c) << (fnb & regSizeMaskUint32)
+				fnb += 8
 			}
-			dist = uint32(bits.Reverse8(uint8(f.b & 0x1F << 3)))
-			f.b >>= 5
-			f.nb -= 5
+			dist = uint32(bits.Reverse8(uint8(fb & 0x1F << 3)))
+			fb >>= 5
+			fnb -= 5
 		} else {
 			// Since a huffmanDecoder can be empty or be composed of a degenerate tree
 			// with single element, huffSym must error on these two edge cases. In both
@@ -884,38 +1160,35 @@ readLiteral:
 			// Optimization. Compiler isn't smart enough to keep f.b,f.nb in registers,
 			// but is smart enough to keep local variables in registers, so use nb and b,
 			// inline call to moreBits and reassign b,nb back to f on return.
-			nb, b := f.nb, f.b
 			for {
-				for nb < n {
+				for fnb < n {
 					c, err := fr.ReadByte()
 					if err != nil {
-						f.b = b
-						f.nb = nb
+						f.b, f.nb = fb, fnb
 						f.err = noEOF(err)
 						return
 					}
 					f.roffset++
-					b |= uint32(c) << (nb & regSizeMaskUint32)
-					nb += 8
+					fb |= uint32(c) << (fnb & regSizeMaskUint32)
+					fnb += 8
 				}
-				chunk := f.hd.chunks[b&(huffmanNumChunks-1)]
+				chunk := f.hd.chunks[fb&(huffmanNumChunks-1)]
 				n = uint(chunk & huffmanCountMask)
 				if n > huffmanChunkBits {
-					chunk = f.hd.links[chunk>>huffmanValueShift][(b>>huffmanChunkBits)&f.hd.linkMask]
+					chunk = f.hd.links[chunk>>huffmanValueShift][(fb>>huffmanChunkBits)&f.hd.linkMask]
 					n = uint(chunk & huffmanCountMask)
 				}
-				if n <= nb {
+				if n <= fnb {
 					if n == 0 {
-						f.b = b
-						f.nb = nb
+						f.b, f.nb = fb, fnb
 						if debugDecode {
 							fmt.Println("huffsym: n==0")
 						}
 						f.err = CorruptInputError(f.roffset)
 						return
 					}
-					f.b = b >> (n & regSizeMaskUint32)
-					f.nb = nb - n
+					fb = fb >> (n & regSizeMaskUint32)
+					fnb = fnb - n
 					dist = uint32(chunk >> huffmanValueShift)
 					break
 				}
@@ -929,9 +1202,10 @@ readLiteral:
 			nb := uint(dist-2) >> 1
 			// have 1 bit in bottom of dist, need nb more.
 			extra := (dist & 1) << (nb & regSizeMaskUint32)
-			for f.nb < nb {
+			for fnb < nb {
 				c, err := fr.ReadByte()
 				if err != nil {
+					f.b, f.nb = fb, fnb
 					if debugDecode {
 						fmt.Println("morebits f.nb<nb:", err)
 					}
@@ -939,14 +1213,16 @@ readLiteral:
 					return
 				}
 				f.roffset++
-				f.b |= uint32(c) << f.nb
-				f.nb += 8
+				fb |= uint32(c) << (fnb & regSizeMaskUint32)
+				fnb += 8
 			}
-			extra |= f.b & uint32(1<<(nb&regSizeMaskUint32)-1)
-			f.b >>= nb & regSizeMaskUint32
-			f.nb -= nb
+			extra |= fb & bitMask32[nb]
+			fb >>= nb & regSizeMaskUint32
+			fnb -= nb
 			dist = 1<<((nb+1)&regSizeMaskUint32) + 1 + extra
+			// slower: dist = bitMask32[nb+1] + 2 + extra
 		default:
+			f.b, f.nb = fb, fnb
 			if debugDecode {
 				fmt.Println("dist too big:", dist, maxNumDist)
 			}
@@ -956,6 +1232,7 @@ readLiteral:
 
 		// No check on length; encoding can be prescient.
 		if dist > uint32(f.dict.histSize()) {
+			f.b, f.nb = fb, fnb
 			if debugDecode {
 				fmt.Println("dist > f.dict.histSize():", dist, f.dict.histSize())
 			}
@@ -978,12 +1255,14 @@ copyHistory:
 
 		if f.dict.availWrite() == 0 || f.copyLen > 0 {
 			f.toRead = f.dict.readFlush()
-			f.step = (*decompressor).huffmanStringsReader // We need to continue this work
+			f.step = (*decompressor).huffmanGenericReader // We need to continue this work
 			f.stepState = stateDict
+			f.b, f.nb = fb, fnb
 			return
 		}
 		goto readLiteral
 	}
+	// Not reached
 }
 
 func (f *decompressor) huffmanBlockDecoder() func() {
@@ -996,7 +1275,9 @@ func (f *decompressor) huffmanBlockDecoder() func() {
 		return f.huffmanBufioReader
 	case *strings.Reader:
 		return f.huffmanStringsReader
+	case Reader:
+		return f.huffmanGenericReader
 	default:
-		return f.huffmanBlockGeneric
+		return f.huffmanGenericReader
 	}
 }
diff --git a/vendor/github.com/klauspost/compress/flate/level1.go b/vendor/github.com/klauspost/compress/flate/level1.go
index 1e5eea396..0022c8bb6 100644
--- a/vendor/github.com/klauspost/compress/flate/level1.go
+++ b/vendor/github.com/klauspost/compress/flate/level1.go
@@ -1,6 +1,10 @@
 package flate
 
-import "fmt"
+import (
+	"encoding/binary"
+	"fmt"
+	"math/bits"
+)
 
 // fastGen maintains the table for matches,
 // and the previous byte block for level 2.
@@ -116,7 +120,32 @@ func (e *fastEncL1) Encode(dst *tokens, src []byte) {
 
 			// Extend the 4-byte match as long as possible.
 			t := candidate.offset - e.cur
-			l := e.matchlenLong(s+4, t+4, src) + 4
+			var l = int32(4)
+			if false {
+				l = e.matchlenLong(s+4, t+4, src) + 4
+			} else {
+				// inlined:
+				a := src[s+4:]
+				b := src[t+4:]
+				for len(a) >= 8 {
+					if diff := binary.LittleEndian.Uint64(a) ^ binary.LittleEndian.Uint64(b); diff != 0 {
+						l += int32(bits.TrailingZeros64(diff) >> 3)
+						break
+					}
+					l += 8
+					a = a[8:]
+					b = b[8:]
+				}
+				if len(a) < 8 {
+					b = b[:len(a)]
+					for i := range a {
+						if a[i] != b[i] {
+							break
+						}
+						l++
+					}
+				}
+			}
 
 			// Extend backwards
 			for t > 0 && s > nextEmit && src[t-1] == src[s-1] {
@@ -129,7 +158,28 @@ func (e *fastEncL1) Encode(dst *tokens, src []byte) {
 			}
 
 			// Save the match found
-			dst.AddMatchLong(l, uint32(s-t-baseMatchOffset))
+			if false {
+				dst.AddMatchLong(l, uint32(s-t-baseMatchOffset))
+			} else {
+				// Inlined...
+				xoffset := uint32(s - t - baseMatchOffset)
+				xlength := l
+				oc := offsetCode(xoffset)
+				xoffset |= oc << 16
+				for xlength > 0 {
+					xl := xlength
+					if xl > 258 {
+						// We need to have at least baseMatchLength left over for next loop.
+						xl = 258 - baseMatchLength
+					}
+					xlength -= xl
+					xl -= baseMatchLength
+					dst.extraHist[lengthCodes1[uint8(xl)]]++
+					dst.offHist[oc]++
+					dst.tokens[dst.n] = token(matchType | uint32(xl)<<lengthShift | xoffset)
+					dst.n++
+				}
+			}
 			s += l
 			nextEmit = s
 			if nextS >= s {
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)
diff --git a/vendor/github.com/klauspost/compress/flate/token.go b/vendor/github.com/klauspost/compress/flate/token.go
index 3a9618ee1..8005a5ca8 100644
--- a/vendor/github.com/klauspost/compress/flate/token.go
+++ b/vendor/github.com/klauspost/compress/flate/token.go
@@ -13,11 +13,10 @@ import (
 )
 
 const (
-	// From top
-	// 2 bits:   type   0 = literal  1=EOF  2=Match   3=Unused
-	// 8 bits:   xlength = length - MIN_MATCH_LENGTH
-	// 5 bits    offsetcode
-	// 16 bits   xoffset = offset - MIN_OFFSET_SIZE, or literal
+	// bits 0-16  	xoffset = offset - MIN_OFFSET_SIZE, or literal - 16 bits
+	// bits 16-22	offsetcode - 5 bits
+	// bits 22-30   xlength = length - MIN_MATCH_LENGTH - 8 bits
+	// bits 30-32   type   0 = literal  1=EOF  2=Match   3=Unused - 2 bits
 	lengthShift         = 22
 	offsetMask          = 1<<lengthShift - 1
 	typeMask            = 3 << 30
@@ -276,7 +275,7 @@ func (t *tokens) AddMatch(xlength uint32, xoffset uint32) {
 	xoffset |= oCode << 16
 
 	t.extraHist[lengthCodes1[uint8(xlength)]]++
-	t.offHist[oCode]++
+	t.offHist[oCode&31]++
 	t.tokens[t.n] = token(matchType | xlength<<lengthShift | xoffset)
 	t.n++
 }
@@ -300,7 +299,7 @@ func (t *tokens) AddMatchLong(xlength int32, xoffset uint32) {
 		xlength -= xl
 		xl -= baseMatchLength
 		t.extraHist[lengthCodes1[uint8(xl)]]++
-		t.offHist[oc]++
+		t.offHist[oc&31]++
 		t.tokens[t.n] = token(matchType | uint32(xl)<<lengthShift | xoffset)
 		t.n++
 	}
@@ -356,8 +355,8 @@ func (t token) offset() uint32 { return uint32(t) & offsetMask }
 
 func (t token) length() uint8 { return uint8(t >> lengthShift) }
 
-// The code is never more than 8 bits, but is returned as uint32 for convenience.
-func lengthCode(len uint8) uint32 { return uint32(lengthCodes[len]) }
+// Convert length to code.
+func lengthCode(len uint8) uint8 { return lengthCodes[len] }
 
 // Returns the offset code corresponding to a specific offset
 func offsetCode(off uint32) uint32 {