compress/flate: optimize huffman bit encoder

Part 1 of optimizing the deflater. This optimizes the bitwriter by:

* Removing allocations.
* Storing compound values for bit codes instead of 2 separate tables.
* Accumulate 48 bits between writes instead of 24.
* Inline bit flushing.

This also contains code that will be used in later CL's
(writeBlockDynamic, writeBlockHuff).

Tests for Huffman bit writer encoding regressions has been added.

name                       old speed      new speed      delta
EncodeDigitsSpeed1e4-4     19.3MB/s ± 1%  21.6MB/s ± 1%  +11.77%
EncodeDigitsSpeed1e5-4     25.0MB/s ± 6%  30.7MB/s ± 1%  +22.70%
EncodeDigitsSpeed1e6-4     28.2MB/s ± 1%  32.3MB/s ± 1%  +14.64%
EncodeDigitsDefault1e4-4   13.3MB/s ± 0%  14.2MB/s ± 1%   +7.07%
EncodeDigitsDefault1e5-4   6.43MB/s ± 1%  6.64MB/s ± 1%   +3.27%
EncodeDigitsDefault1e6-4   5.81MB/s ± 0%  5.85MB/s ± 1%   +0.69%
EncodeDigitsCompress1e4-4  13.2MB/s ± 0%  14.4MB/s ± 0%   +9.10%
EncodeDigitsCompress1e5-4  6.40MB/s ± 1%  6.61MB/s ± 0%   +3.20%
EncodeDigitsCompress1e6-4  5.80MB/s ± 1%  5.90MB/s ± 1%   +1.64%
EncodeTwainSpeed1e4-4      18.4MB/s ± 1%  20.7MB/s ± 1%  +12.72%
EncodeTwainSpeed1e5-4      27.7MB/s ± 1%  31.0MB/s ± 1%  +11.78%
EncodeTwainSpeed1e6-4      29.1MB/s ± 0%  32.9MB/s ± 2%  +13.25%
EncodeTwainDefault1e4-4    12.4MB/s ± 0%  13.1MB/s ± 1%   +5.88%
EncodeTwainDefault1e5-4    7.52MB/s ± 1%  7.83MB/s ± 0%   +4.19%
EncodeTwainDefault1e6-4    7.08MB/s ± 1%  7.26MB/s ± 0%   +2.54%
EncodeTwainCompress1e4-4   12.0MB/s ± 1%  12.8MB/s ± 1%   +6.70%
EncodeTwainCompress1e5-4   5.96MB/s ± 1%  6.16MB/s ± 0%   +3.27%
EncodeTwainCompress1e6-4   5.37MB/s ± 0%  5.39MB/s ± 1%   +0.47%

>Allocations:

benchmark                              old allocs     new allocs     delta
BenchmarkEncodeDigitsSpeed1e4-4        50             0              -100.00%
BenchmarkEncodeDigitsSpeed1e5-4        110            0              -100.00%
BenchmarkEncodeDigitsSpeed1e6-4        1032           0              -100.00%
BenchmarkEncodeDigitsDefault1e4-4      56             0              -100.00%
BenchmarkEncodeDigitsDefault1e5-4      120            0              -100.00%
BenchmarkEncodeDigitsDefault1e6-4      966            0              -100.00%
BenchmarkEncodeDigitsCompress1e4-4     56             0              -100.00%
BenchmarkEncodeDigitsCompress1e5-4     120            0              -100.00%
BenchmarkEncodeDigitsCompress1e6-4     966            0              -100.00%
BenchmarkEncodeTwainSpeed1e4-4         58             0              -100.00%
BenchmarkEncodeTwainSpeed1e5-4         132            0              -100.00%
BenchmarkEncodeTwainSpeed1e6-4         1082           0              -100.00%
BenchmarkEncodeTwainDefault1e4-4       52             0              -100.00%
BenchmarkEncodeTwainDefault1e5-4       126            0              -100.00%
BenchmarkEncodeTwainDefault1e6-4       886            0              -100.00%
BenchmarkEncodeTwainCompress1e4-4      52             0              -100.00%
BenchmarkEncodeTwainCompress1e5-4      120            0              -100.00%
BenchmarkEncodeTwainCompress1e6-4      880            0              -100.00%

benchmark                              old bytes     new bytes     delta
BenchmarkEncodeDigitsSpeed1e4-4        4288          2             -99.95%
BenchmarkEncodeDigitsSpeed1e5-4        8896          15            -99.83%
BenchmarkEncodeDigitsSpeed1e6-4        84098         153           -99.82%
BenchmarkEncodeDigitsDefault1e4-4      4480          3             -99.93%
BenchmarkEncodeDigitsDefault1e5-4      9216          76            -99.18%
BenchmarkEncodeDigitsDefault1e6-4      73920         768           -98.96%
BenchmarkEncodeDigitsCompress1e4-4     4480          3             -99.93%
BenchmarkEncodeDigitsCompress1e5-4     9216          76            -99.18%
BenchmarkEncodeDigitsCompress1e6-4     73920         768           -98.96%
BenchmarkEncodeTwainSpeed1e4-4         4544          2             -99.96%
BenchmarkEncodeTwainSpeed1e5-4         9600          15            -99.84%
BenchmarkEncodeTwainSpeed1e6-4         77633         153           -99.80%
BenchmarkEncodeTwainDefault1e4-4       4352          3             -99.93%
BenchmarkEncodeTwainDefault1e5-4       9408          76            -99.19%
BenchmarkEncodeTwainDefault1e6-4       65984         768           -98.84%
BenchmarkEncodeTwainCompress1e4-4      4352          3             -99.93%
BenchmarkEncodeTwainCompress1e5-4      9216          76            -99.18%
BenchmarkEncodeTwainCompress1e6-4      65792         768           -98.83%

Updates #14258

Change-Id: Ibaa97b9619743ad623094727228eb2ada1ec7f1f
Reviewed-on: https://go-review.googlesource.com/19336Reviewed-by: Nigel Tao <nigeltao@golang.org>
Reviewed-by: Joe Tsai <joetsai@digital-static.net>
Run-TryBot: Joe Tsai <joetsai@digital-static.net>
TryBot-Result: Gobot Gobot <gobot@golang.org>

misc/nacl/testzip.proto

@@ -56,6 +56,8 @@ go	src=..
 				testdata
 					+
 			flate
+				testdata
+					+
 			gzip
 				testdata
 					+

src/compress/flate/huffman_code.go

@@ -9,9 +9,17 @@ import (
 	"sort"
 )
 
+// hcode is a huffman code with a bit code and bit length.
+type hcode struct {
+	code, len uint16
+}
+
 type huffmanEncoder struct {
-	codeBits []uint8
-	code     []uint16
+	codes     []hcode
+	freqcache []literalNode
+	bitCount  [17]int32
+	lns       byLiteral // stored to avoid repeated allocation in generate
+	lfs       byFreq    // stored to avoid repeated allocation in generate
 }
 
 type literalNode struct {
@@ -39,21 +47,26 @@ type levelInfo struct {
 	needed int32
 }
 
+// set sets the code and length of an hcode.
+func (h *hcode) set(code uint16, length uint16) {
+	h.len = length
+	h.code = code
+}
+
 func maxNode() literalNode { return literalNode{math.MaxUint16, math.MaxInt32} }
 
 func newHuffmanEncoder(size int) *huffmanEncoder {
-	return &huffmanEncoder{make([]uint8, size), make([]uint16, size)}
+	return &huffmanEncoder{codes: make([]hcode, size)}
 }
 
 // Generates a HuffmanCode corresponding to the fixed literal table
 func generateFixedLiteralEncoding() *huffmanEncoder {
 	h := newHuffmanEncoder(maxNumLit)
-	codeBits := h.codeBits
-	code := h.code
+	codes := h.codes
 	var ch uint16
 	for ch = 0; ch < maxNumLit; ch++ {
 		var bits uint16
-		var size uint8
+		var size uint16
 		switch {
 		case ch < 144:
 			// size 8, 000110000  .. 10111111
@@ -75,19 +88,16 @@ func generateFixedLiteralEncoding() *huffmanEncoder {
 			bits = ch + 192 - 280
 			size = 8
 		}
-		codeBits[ch] = size
-		code[ch] = reverseBits(bits, size)
+		codes[ch] = hcode{code: reverseBits(bits, byte(size)), len: size}
 	}
 	return h
 }
 
 func generateFixedOffsetEncoding() *huffmanEncoder {
 	h := newHuffmanEncoder(30)
-	codeBits := h.codeBits
-	code := h.code
+	codes := h.codes
 	for ch := uint16(0); ch < 30; ch++ {
-		codeBits[ch] = 5
-		code[ch] = reverseBits(ch, 5)
+		codes[ch] = hcode{code: reverseBits(ch, 5), len: 5}
 	}
 	return h
 }
@@ -99,7 +109,7 @@ func (h *huffmanEncoder) bitLength(freq []int32) int64 {
 	var total int64
 	for i, f := range freq {
 		if f != 0 {
-			total += int64(f) * int64(h.codeBits[i])
+			total += int64(f) * int64(h.codes[i].len)
 		}
 	}
 	return total
@@ -220,7 +230,7 @@ func (h *huffmanEncoder) bitCounts(list []literalNode, maxBits int32) []int32 {
 		panic("leafCounts[maxBits][maxBits] != n")
 	}
 
-	bitCount := make([]int32, maxBits+1)
+	bitCount := h.bitCount[:maxBits+1]
 	bits := 1
 	counts := &leafCounts[maxBits]
 	for level := maxBits; level > 0; level-- {
@@ -246,10 +256,10 @@ func (h *huffmanEncoder) assignEncodingAndSize(bitCount []int32, list []literalN
 		// code, code + 1, ....  The code values are
 		// assigned in literal order (not frequency order).
 		chunk := list[len(list)-int(bits):]
-		sortByLiteral(chunk)
+
+		h.lns.sort(chunk)
 		for _, node := range chunk {
-			h.codeBits[node.literal] = uint8(n)
-			h.code[node.literal] = reverseBits(code, uint8(n))
+			h.codes[node.literal] = hcode{code: reverseBits(code, uint8(n)), len: uint16(n)}
 			code++
 		}
 		list = list[0 : len(list)-int(bits)]
@@ -261,7 +271,13 @@ func (h *huffmanEncoder) assignEncodingAndSize(bitCount []int32, list []literalN
 // freq  An array of frequencies, in which frequency[i] gives the frequency of literal i.
 // maxBits  The maximum number of bits to use for any literal.
 func (h *huffmanEncoder) generate(freq []int32, maxBits int32) {
-	list := make([]literalNode, len(freq)+1)
+	if h.freqcache == nil {
+		// Allocate a reusable buffer with the longest possible frequency table.
+		// Possible lengths are codegenCodeCount, offsetCodeCount and maxNumLit.
+		// The largest of these is maxNumLit, so we allocate for that case.
+		h.freqcache = make([]literalNode, maxNumLit+1)
+	}
+	list := h.freqcache[:len(freq)+1]
 	// Number of non-zero literals
 	count := 0
 	// Set list to be the set of all non-zero literals and their frequencies
@@ -270,23 +286,23 @@ func (h *huffmanEncoder) generate(freq []int32, maxBits int32) {
 			list[count] = literalNode{uint16(i), f}
 			count++
 		} else {
-			h.codeBits[i] = 0
+			list[count] = literalNode{}
+			h.codes[i].len = 0
 		}
 	}
-	// If freq[] is shorter than codeBits[], fill rest of codeBits[] with zeros
-	h.codeBits = h.codeBits[0:len(freq)]
-	list = list[0:count]
+	list[len(freq)] = literalNode{}
+
+	list = list[:count]
 	if count <= 2 {
 		// Handle the small cases here, because they are awkward for the general case code. With
 		// two or fewer literals, everything has bit length 1.
 		for i, node := range list {
 			// "list" is in order of increasing literal value.
-			h.codeBits[node.literal] = 1
-			h.code[node.literal] = uint16(i)
+			h.codes[node.literal].set(uint16(i), 1)
 		}
 		return
 	}
-	sortByFreq(list)
+	h.lfs.sort(list)
 
 	// Get the number of literals for each bit count
 	bitCount := h.bitCounts(list, maxBits)
@@ -294,30 +310,35 @@ func (h *huffmanEncoder) generate(freq []int32, maxBits int32) {
 	h.assignEncodingAndSize(bitCount, list)
 }
 
-type literalNodeSorter struct {
-	a    []literalNode
-	less func(i, j int) bool
+type byLiteral []literalNode
+
+func (s *byLiteral) sort(a []literalNode) {
+	*s = byLiteral(a)
+	sort.Sort(s)
 }
 
-func (s literalNodeSorter) Len() int { return len(s.a) }
+func (s byLiteral) Len() int { return len(s) }
 
-func (s literalNodeSorter) Less(i, j int) bool {
-	return s.less(i, j)
+func (s byLiteral) Less(i, j int) bool {
+	return s[i].literal < s[j].literal
 }
 
-func (s literalNodeSorter) Swap(i, j int) { s.a[i], s.a[j] = s.a[j], s.a[i] }
+func (s byLiteral) Swap(i, j int) { s[i], s[j] = s[j], s[i] }
 
-func sortByFreq(a []literalNode) {
-	s := &literalNodeSorter{a, func(i, j int) bool {
-		if a[i].freq == a[j].freq {
-			return a[i].literal < a[j].literal
-		}
-		return a[i].freq < a[j].freq
-	}}
+type byFreq []literalNode
+
+func (s *byFreq) sort(a []literalNode) {
+	*s = byFreq(a)
 	sort.Sort(s)
 }
 
-func sortByLiteral(a []literalNode) {
-	s := &literalNodeSorter{a, func(i, j int) bool { return a[i].literal < a[j].literal }}
-	sort.Sort(s)
+func (s byFreq) Len() int { return len(s) }
+
+func (s byFreq) Less(i, j int) bool {
+	if s[i].freq == s[j].freq {
+		return s[i].literal < s[j].literal
+	}
+	return s[i].freq < s[j].freq
 }
+
+func (s byFreq) Swap(i, j int) { s[i], s[j] = s[j], s[i] }

src/compress/flate/testdata/huffman-pi.in

+3.141592653589793238462643383279502884197169399375105820974944592307816406286208998628034825342117067982148086513282306647093844609550582231725359408128481117450284102701938521105559644622948954930381964428810975665933446128475648233786783165271201909145648566923460348610454326648213393607260249141273724587006606315588174881520920962829254091715364367892590360011330530548820466521384146951941511609433057270365759591953092186117381932611793105118548074462379962749567351885752724891227938183011949129833673362440656643086021394946395224737190702179860943702770539217176293176752384674818467669405132000568127145263560827785771342757789609173637178721468440901224953430146549585371050792279689258923542019956112129021960864034418159813629774771309960518707211349999998372978049951059731732816096318595024459455346908302642522308253344685035261931188171010003137838752886587533208381420617177669147303598253490428755468731159562863882353787593751957781857780532171226806613001927876611195909216420198938095257201065485863278865936153381827968230301952035301852968995773622599413891249721775283479131515574857242454150695950829533116861727855889075098381754637464939319255060400927701671139009848824012858361603563707660104710181942955596198946767837449448255379774726847104047534646208046684259069491293313677028989152104752162056966024058038150193511253382430035587640247496473263914199272604269922796782354781636009341721641219924586315030286182974555706749838505494588586926995690927210797509302955321165344987202755960236480665499119881834797753566369807426542527862551818417574672890977772793800081647060016145249192173217214772350141441973568548161361157352552133475741849468438523323907394143334547762416862518983569485562099219222184272550254256887671790494601653466804988627232791786085784383827967976681454100953883786360950680064225125205117392984896084128488626945604241965285022210661186306744278622039194945047123713786960956364371917287467764657573962413890865832645995813390478027590099465764078951269468398352595709825822620522489407726719478268482601476990902640136394437455305068203496252451749399651431429809190659250937221696461515709858387410597885959772975498930161753928468138268683868942774155991855925245953959431049972524680845987273644695848653836736222626099124608051243884390451244136549762780797715691435997700129616089441694868555848406353422072225828488648158456028506016842739452267467678895252138522549954666727823986456596116354886230577456498035593634568174324112515076069479451096596094025228879710893145669136867228748940560101503308617928680920874760917824938589009714909675985261365549781893129784821682998948722658804857564014270477555132379641451523746234364542858444795265867821051141354735739523113427166102135969536231442952484937187110145765403590279934403742007310578539062198387447808478489683321445713868751943506430218453191048481005370614680674919278191197939952061419663428754440643745123718192179998391015919561814675142691239748940907186494231961567945208095146550225231603881930142093762137855956638937787083039069792077346722182562599661501421503068038447734549202605414665925201497442850732518666002132434088190710486331734649651453905796268561005508106658796998163574736384052571459102897064140110971206280439039759515677157700420337869936007230558763176359421873125147120532928191826186125867321579198414848829164470609575270695722091756711672291098169091528017350671274858322287183520935396572512108357915136988209144421006751033467110314126711136990865851639831501970165151168517143765761835155650884909989859982387345528331635507647918535893226185489632132933089857064204675259070915481416549859461637180
\ No newline at end of file

src/compress/flate/testdata/huffman-rand-limit.in

+aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
+vH
+% ɷ}>lsmIGH1Y4[	0ˆ[|]o#
+-#ulpfٱnYԀYwC8ɯ02 F=gnrN!O{k*w(b kQC9/
lu>5C.u

src/compress/flate/testdata/huffman-shifts.in

+101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010
+232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323232323
\ No newline at end of file

src/compress/flate/testdata/huffman-text-shift.in

+//Copyright2009ThGoAuthor.Allrightrrvd.
+//UofthiourccodigovrndbyBSD-tyl
+//licnthtcnbfoundinthLICENSEfil.
+
+pckgmin
+
+import"o"
+
+funcmin(){
+	vrb=mk([]byt,65535)
+	f,_:=o.Crt("huffmn-null-mx.in")
+	f.Writ(b)
+}
+ABCDEFGHIJKLMNOPQRSTUVXxyz!"#¤%&/?"
\ No newline at end of file

src/compress/flate/testdata/huffman-text.dyn.expect

+_K0`K0Aasě)^HIɟb߻_>4
a=-^
1`_	1		ő:Y-F66!A`aC;ANyr4ߜU!GKС#r:B[G3.L׶bFRuM]^⇳(#ZivBBH2S]u/ֽWTGnr
\ No newline at end of file

src/compress/flate/testdata/huffman-text.dyn.expect-noinput

+_K0`K0Aasě)^HIɟb߻_>4
a=-^
1`_	1		ő:Y-F66!A`aC;ANyr4ߜU!GKС#r:B[G3.L׶bFRuM]^⇳(#ZivBBH2S]u/ֽWTGnr
\ No newline at end of file

src/compress/flate/testdata/huffman-text.golden

+AK0xßZLPa!xADI&#IEp]LƿFp	188h$5S-	F66!)v.0Y&	SN|d2:
+t|둍xz9骺Ɏ3
+&&=ôUD=Fu]qUL+>FQYLZofTߵEŴ{Yʶbe
\ No newline at end of file

src/compress/flate/testdata/huffman-text.in

+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package main
+
+import "os"
+
+func main() {
+	var b = make([]byte, 65535)
+	f, _ := os.Create("huffman-null-max.in")
+	f.Write(b)
+}

src/compress/flate/testdata/huffman-text.wb.expect

+_K0`K0Aasě)^HIɟb߻_>4
a=-^
1`_	1		ő:Y-F66!A`aC;ANyr4ߜU!GKС#r:B[G3.L׶bFRuM]^⇳(#ZivBBH2S]u/ֽWTGnr
\ No newline at end of file

src/compress/flate/testdata/huffman-text.wb.expect-noinput

+_K0`K0Aasě)^HIɟb߻_>4
a=-^
1`_	1		ő:Y-F66!A`aC;ANyr4ߜU!GKС#r:B[G3.L׶bFRuM]^⇳(#ZivBBH2S]u/ֽWTGnr
\ No newline at end of file

src/compress/flate/testdata/huffman-zero.in

+00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
\ No newline at end of file