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Merge pull request #3832 from dgageot/faster-gzip

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Use faster gzip library
This commit is contained in:
Avi Deitcher
2022-10-06 16:25:38 +03:00
committed by GitHub
parent 0a223ec205 eda59aa5ab
commit 0f6ed01f2b
32 changed files with 8996 additions and 3 deletions
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1
src/cmd/linuxkit/go.mod
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@@ -27,6 +27,7 @@ require (
github.com/gophercloud/gophercloud v0.1.0
github.com/gophercloud/utils v0.0.0-20181029231510-34f5991525d1
github.com/hashicorp/go-version v1.2.0
github.com/klauspost/pgzip v1.2.5
github.com/moby/buildkit v0.10.1-0.20220721175135-c75998aec3d4
github.com/moby/hyperkit v0.0.0-20180416161519-d65b09c1c28a
//github.com/moby/moby v20.10.3-0.20220728162118-71cb54cec41e+incompatible // indirect

2
src/cmd/linuxkit/go.sum
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@@ -989,6 +989,8 @@ github.com/klauspost/compress v1.15.1 h1:y9FcTHGyrebwfP0ZZqFiaxTaiDnUrGkJkI+f583
github.com/klauspost/compress v1.15.1/go.mod h1:/3/Vjq9QcHkK5uEr5lBEmyoZ1iFhe47etQ6QUkpK6sk=
github.com/klauspost/cpuid v0.0.0-20180405133222-e7e905edc00e/go.mod h1:Pj4uuM528wm8OyEC2QMXAi2YiTZ96dNQPGgoMS4s3ek=
github.com/klauspost/cpuid v1.2.0/go.mod h1:Pj4uuM528wm8OyEC2QMXAi2YiTZ96dNQPGgoMS4s3ek=
github.com/klauspost/pgzip v1.2.5 h1:qnWYvvKqedOF2ulHpMG72XQol4ILEJ8k2wwRl/Km8oE=
github.com/klauspost/pgzip v1.2.5/go.mod h1:Ch1tH69qFZu15pkjo5kYi6mth2Zzwzt50oCQKQE9RUs=
github.com/konsorten/go-windows-terminal-sequences v1.0.1/go.mod h1:T0+1ngSBFLxvqU3pZ+m/2kptfBszLMUkC4ZK/EgS/cQ=
github.com/konsorten/go-windows-terminal-sequences v1.0.2/go.mod h1:T0+1ngSBFLxvqU3pZ+m/2kptfBszLMUkC4ZK/EgS/cQ=
github.com/konsorten/go-windows-terminal-sequences v1.0.3/go.mod h1:T0+1ngSBFLxvqU3pZ+m/2kptfBszLMUkC4ZK/EgS/cQ=

3
src/cmd/linuxkit/initrd/initrd.go
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@@ -3,13 +3,14 @@ package initrd
import (
"archive/tar"
"bytes"
"compress/gzip"
"errors"
"io"
"io/ioutil"
"path/filepath"
"strings"
// drop-in 100% compatible replacement and 17% faster than compress/gzip.
gzip "github.com/klauspost/pgzip"
"github.com/linuxkit/linuxkit/src/cmd/linuxkit/pad4"
"github.com/surma/gocpio"
)

3
src/cmd/linuxkit/moby/build.go
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@@ -3,7 +3,6 @@ package moby
import (
"archive/tar"
"bytes"
"compress/gzip"
"encoding/binary"
"encoding/json"
"errors"
@@ -18,6 +17,8 @@ import (
"strings"
"github.com/containerd/containerd/reference"
// drop-in 100% compatible replacement and 17% faster than compress/gzip.
gzip "github.com/klauspost/pgzip"
"github.com/linuxkit/linuxkit/src/cmd/linuxkit/util"
log "github.com/sirupsen/logrus"
"gopkg.in/yaml.v2"

3
src/cmd/linuxkit/push_packet.go
View File

@@ -1,7 +1,6 @@
package main
import (
"compress/gzip"
"flag"
"fmt"
"io"
@@ -11,6 +10,8 @@ import (
"path/filepath"
"runtime"
// drop-in 100% compatible replacement and 17% faster than compress/gzip.
gzip "github.com/klauspost/pgzip"
log "github.com/sirupsen/logrus"
)

911
src/cmd/linuxkit/vendor/github.com/klauspost/compress/flate/deflate.go generated vendored Normal file
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@@ -0,0 +1,911 @@
// Copyright 2009 The Go Authors. All rights reserved.
// Copyright (c) 2015 Klaus Post
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package flate
import (
"encoding/binary"
"fmt"
"io"
"math"
)
const (
NoCompression = 0
BestSpeed = 1
BestCompression = 9
DefaultCompression = -1
// HuffmanOnly disables Lempel-Ziv match searching and only performs Huffman
// entropy encoding. This mode is useful in compressing data that has
// already been compressed with an LZ style algorithm (e.g. Snappy or LZ4)
// that lacks an entropy encoder. Compression gains are achieved when
// certain bytes in the input stream occur more frequently than others.
//
// Note that HuffmanOnly produces a compressed output that is
// RFC 1951 compliant. That is, any valid DEFLATE decompressor will
// continue to be able to decompress this output.
HuffmanOnly = -2
ConstantCompression = HuffmanOnly // compatibility alias.
logWindowSize = 15
windowSize = 1 << logWindowSize
windowMask = windowSize - 1
logMaxOffsetSize = 15 // Standard DEFLATE
minMatchLength = 4 // The smallest match that the compressor looks for
maxMatchLength = 258 // The longest match for the compressor
minOffsetSize = 1 // The shortest offset that makes any sense
// The maximum number of tokens we will encode at the time.
// Smaller sizes usually creates less optimal blocks.
// Bigger can make context switching slow.
// We use this for levels 7-9, so we make it big.
maxFlateBlockTokens = 1 << 15
maxStoreBlockSize = 65535
hashBits = 17 // After 17 performance degrades
hashSize = 1 << hashBits
hashMask = (1 << hashBits) - 1
hashShift = (hashBits + minMatchLength - 1) / minMatchLength
maxHashOffset = 1 << 28
skipNever = math.MaxInt32
debugDeflate = false
)
type compressionLevel struct {
good, lazy, nice, chain, fastSkipHashing, level int
}
// Compression levels have been rebalanced from zlib deflate defaults
// to give a bigger spread in speed and compression.
// See https://blog.klauspost.com/rebalancing-deflate-compression-levels/
var levels = []compressionLevel{
{}, // 0
// Level 1-6 uses specialized algorithm - values not used
{0, 0, 0, 0, 0, 1},
{0, 0, 0, 0, 0, 2},
{0, 0, 0, 0, 0, 3},
{0, 0, 0, 0, 0, 4},
{0, 0, 0, 0, 0, 5},
{0, 0, 0, 0, 0, 6},
// Levels 7-9 use increasingly more lazy matching
// and increasingly stringent conditions for "good enough".
{8, 12, 16, 24, skipNever, 7},
{16, 30, 40, 64, skipNever, 8},
{32, 258, 258, 1024, skipNever, 9},
}
// advancedState contains state for the advanced levels, with bigger hash tables, etc.
type advancedState struct {
// deflate state
length int
offset int
maxInsertIndex int
// Input hash chains
// hashHead[hashValue] contains the largest inputIndex with the specified hash value
// If hashHead[hashValue] is within the current window, then
// hashPrev[hashHead[hashValue] & windowMask] contains the previous index
// with the same hash value.
chainHead int
hashHead [hashSize]uint32
hashPrev [windowSize]uint32
hashOffset int
// input window: unprocessed data is window[index:windowEnd]
index int
estBitsPerByte int
hashMatch [maxMatchLength + minMatchLength]uint32
hash uint32
ii uint16 // position of last match, intended to overflow to reset.
}
type compressor struct {
compressionLevel
h *huffmanEncoder
w *huffmanBitWriter
// compression algorithm
fill func(*compressor, []byte) int // copy data to window
step func(*compressor) // process window
window []byte
windowEnd int
blockStart int // window index where current tokens start
err error
// queued output tokens
tokens tokens
fast fastEnc
state *advancedState
sync bool // requesting flush
byteAvailable bool // if true, still need to process window[index-1].
}
func (d *compressor) fillDeflate(b []byte) int {
s := d.state
if s.index >= 2*windowSize-(minMatchLength+maxMatchLength) {
// shift the window by windowSize
copy(d.window[:], d.window[windowSize:2*windowSize])
s.index -= windowSize
d.windowEnd -= windowSize
if d.blockStart >= windowSize {
d.blockStart -= windowSize
} else {
d.blockStart = math.MaxInt32
}
s.hashOffset += windowSize
if s.hashOffset > maxHashOffset {
delta := s.hashOffset - 1
s.hashOffset -= delta
s.chainHead -= delta
// Iterate over slices instead of arrays to avoid copying
// the entire table onto the stack (Issue #18625).
for i, v := range s.hashPrev[:] {
if int(v) > delta {
s.hashPrev[i] = uint32(int(v) - delta)
} else {
s.hashPrev[i] = 0
}
}
for i, v := range s.hashHead[:] {
if int(v) > delta {
s.hashHead[i] = uint32(int(v) - delta)
} else {
s.hashHead[i] = 0
}
}
}
}
n := copy(d.window[d.windowEnd:], b)
d.windowEnd += n
return n
}
func (d *compressor) writeBlock(tok *tokens, index int, eof bool) error {
if index > 0 || eof {
var window []byte
if d.blockStart <= index {
window = d.window[d.blockStart:index]
}
d.blockStart = index
//d.w.writeBlock(tok, eof, window)
d.w.writeBlockDynamic(tok, eof, window, d.sync)
return d.w.err
}
return nil
}
// writeBlockSkip writes the current block and uses the number of tokens
// to determine if the block should be stored on no matches, or
// only huffman encoded.
func (d *compressor) writeBlockSkip(tok *tokens, index int, eof bool) error {
if index > 0 || eof {
if d.blockStart <= index {
window := d.window[d.blockStart:index]
// If we removed less than a 64th of all literals
// we huffman compress the block.
if int(tok.n) > len(window)-int(tok.n>>6) {
d.w.writeBlockHuff(eof, window, d.sync)
} else {
// Write a dynamic huffman block.
d.w.writeBlockDynamic(tok, eof, window, d.sync)
}
} else {
d.w.writeBlock(tok, eof, nil)
}
d.blockStart = index
return d.w.err
}
return nil
}
// fillWindow will fill the current window with the supplied
// dictionary and calculate all hashes.
// This is much faster than doing a full encode.
// Should only be used after a start/reset.
func (d *compressor) fillWindow(b []byte) {
// Do not fill window if we are in store-only or huffman mode.
if d.level <= 0 {
return
}
if d.fast != nil {
// encode the last data, but discard the result
if len(b) > maxMatchOffset {
b = b[len(b)-maxMatchOffset:]
}
d.fast.Encode(&d.tokens, b)
d.tokens.Reset()
return
}
s := d.state
// If we are given too much, cut it.
if len(b) > windowSize {
b = b[len(b)-windowSize:]
}
// Add all to window.
n := copy(d.window[d.windowEnd:], b)
// Calculate 256 hashes at the time (more L1 cache hits)
loops := (n + 256 - minMatchLength) / 256
for j := 0; j < loops; j++ {
startindex := j * 256
end := startindex + 256 + minMatchLength - 1
if end > n {
end = n
}
tocheck := d.window[startindex:end]
dstSize := len(tocheck) - minMatchLength + 1
if dstSize <= 0 {
continue
}
dst := s.hashMatch[:dstSize]
bulkHash4(tocheck, dst)
var newH uint32
for i, val := range dst {
di := i + startindex
newH = val & hashMask
// Get previous value with the same hash.
// Our chain should point to the previous value.
s.hashPrev[di&windowMask] = s.hashHead[newH]
// Set the head of the hash chain to us.
s.hashHead[newH] = uint32(di + s.hashOffset)
}
s.hash = newH
}
// Update window information.
d.windowEnd += n
s.index = n
}
// Try to find a match starting at index whose length is greater than prevSize.
// We only look at chainCount possibilities before giving up.
// pos = s.index, prevHead = s.chainHead-s.hashOffset, prevLength=minMatchLength-1, lookahead
func (d *compressor) findMatch(pos int, prevHead int, lookahead int) (length, offset int, ok bool) {
minMatchLook := maxMatchLength
if lookahead < minMatchLook {
minMatchLook = lookahead
}
win := d.window[0 : pos+minMatchLook]
// We quit when we get a match that's at least nice long
nice := len(win) - pos
if d.nice < nice {
nice = d.nice
}
// If we've got a match that's good enough, only look in 1/4 the chain.
tries := d.chain
length = minMatchLength - 1
wEnd := win[pos+length]
wPos := win[pos:]
minIndex := pos - windowSize
if minIndex < 0 {
minIndex = 0
}
offset = 0
cGain := 0
if d.chain < 100 {
for i := prevHead; tries > 0; tries-- {
if wEnd == win[i+length] {
n := matchLen(win[i:i+minMatchLook], wPos)
if n > length {
length = n
offset = pos - i
ok = true
if n >= nice {
// The match is good enough that we don't try to find a better one.
break
}
wEnd = win[pos+n]
}
}
if i <= minIndex {
// hashPrev[i & windowMask] has already been overwritten, so stop now.
break
}
i = int(d.state.hashPrev[i&windowMask]) - d.state.hashOffset
if i < minIndex {
break
}
}
return
}
// Some like it higher (CSV), some like it lower (JSON)
const baseCost = 6
// Base is 4 bytes at with an additional cost.
// Matches must be better than this.
for i := prevHead; tries > 0; tries-- {
if wEnd == win[i+length] {
n := matchLen(win[i:i+minMatchLook], wPos)
if n > length {
// Calculate gain. Estimate
newGain := d.h.bitLengthRaw(wPos[:n]) - int(offsetExtraBits[offsetCode(uint32(pos-i))]) - baseCost - int(lengthExtraBits[lengthCodes[(n-3)&255]])
//fmt.Println(n, "gain:", newGain, "prev:", cGain, "raw:", d.h.bitLengthRaw(wPos[:n]))
if newGain > cGain {
length = n
offset = pos - i
cGain = newGain
ok = true
if n >= nice {
// The match is good enough that we don't try to find a better one.
break
}
wEnd = win[pos+n]
}
}
}
if i <= minIndex {
// hashPrev[i & windowMask] has already been overwritten, so stop now.
break
}
i = int(d.state.hashPrev[i&windowMask]) - d.state.hashOffset
if i < minIndex {
break
}
}
return
}
func (d *compressor) writeStoredBlock(buf []byte) error {
if d.w.writeStoredHeader(len(buf), false); d.w.err != nil {
return d.w.err
}
d.w.writeBytes(buf)
return d.w.err
}
// hash4 returns a hash representation of the first 4 bytes
// of the supplied slice.
// The caller must ensure that len(b) >= 4.
func hash4(b []byte) uint32 {
return hash4u(binary.LittleEndian.Uint32(b), hashBits)
}
// bulkHash4 will compute hashes using the same
// algorithm as hash4
func bulkHash4(b []byte, dst []uint32) {
if len(b) < 4 {
return
}
hb := binary.LittleEndian.Uint32(b)
dst[0] = hash4u(hb, hashBits)
end := len(b) - 4 + 1
for i := 1; i < end; i++ {
hb = (hb >> 8) | uint32(b[i+3])<<24
dst[i] = hash4u(hb, hashBits)
}
}
func (d *compressor) initDeflate() {
d.window = make([]byte, 2*windowSize)
d.byteAvailable = false
d.err = nil
if d.state == nil {
return
}
s := d.state
s.index = 0
s.hashOffset = 1
s.length = minMatchLength - 1
s.offset = 0
s.hash = 0
s.chainHead = -1
}
// deflateLazy is the same as deflate, but with d.fastSkipHashing == skipNever,
// meaning it always has lazy matching on.
func (d *compressor) deflateLazy() {
s := d.state
// Sanity enables additional runtime tests.
// It's intended to be used during development
// to supplement the currently ad-hoc unit tests.
const sanity = debugDeflate
if d.windowEnd-s.index < minMatchLength+maxMatchLength && !d.sync {
return
}
if d.windowEnd != s.index && d.chain > 100 {
// Get literal huffman coder.
if d.h == nil {
d.h = newHuffmanEncoder(maxFlateBlockTokens)
}
var tmp [256]uint16
for _, v := range d.window[s.index:d.windowEnd] {
tmp[v]++
}
d.h.generate(tmp[:], 15)
}
s.maxInsertIndex = d.windowEnd - (minMatchLength - 1)
if s.index < s.maxInsertIndex {
s.hash = hash4(d.window[s.index:])
}
for {
if sanity && s.index > d.windowEnd {
panic("index > windowEnd")
}
lookahead := d.windowEnd - s.index
if lookahead < minMatchLength+maxMatchLength {
if !d.sync {
return
}
if sanity && s.index > d.windowEnd {
panic("index > windowEnd")
}
if lookahead == 0 {
// Flush current output block if any.
if d.byteAvailable {
// There is still one pending token that needs to be flushed
d.tokens.AddLiteral(d.window[s.index-1])
d.byteAvailable = false
}
if d.tokens.n > 0 {
if d.err = d.writeBlock(&d.tokens, s.index, false); d.err != nil {
return
}
d.tokens.Reset()
}
return
}
}
if s.index < s.maxInsertIndex {
// Update the hash
s.hash = hash4(d.window[s.index:])
ch := s.hashHead[s.hash&hashMask]
s.chainHead = int(ch)
s.hashPrev[s.index&windowMask] = ch
s.hashHead[s.hash&hashMask] = uint32(s.index + s.hashOffset)
}
prevLength := s.length
prevOffset := s.offset
s.length = minMatchLength - 1
s.offset = 0
minIndex := s.index - windowSize
if minIndex < 0 {
minIndex = 0
}
if s.chainHead-s.hashOffset >= minIndex && lookahead > prevLength && prevLength < d.lazy {
if newLength, newOffset, ok := d.findMatch(s.index, s.chainHead-s.hashOffset, lookahead); ok {
s.length = newLength
s.offset = newOffset
}
}
if prevLength >= minMatchLength && s.length <= prevLength {
// Check for better match at end...
//
// checkOff must be >=2 since we otherwise risk checking s.index
// Offset of 2 seems to yield best results.
const checkOff = 2
prevIndex := s.index - 1
if prevIndex+prevLength+checkOff < s.maxInsertIndex {
end := lookahead
if lookahead > maxMatchLength {
end = maxMatchLength
}
end += prevIndex
idx := prevIndex + prevLength - (4 - checkOff)
h := hash4(d.window[idx:])
ch2 := int(s.hashHead[h&hashMask]) - s.hashOffset - prevLength + (4 - checkOff)
if ch2 > minIndex {
length := matchLen(d.window[prevIndex:end], d.window[ch2:])
// It seems like a pure length metric is best.
if length > prevLength {
prevLength = length
prevOffset = prevIndex - ch2
}
}
}
// There was a match at the previous step, and the current match is
// not better. Output the previous match.
d.tokens.AddMatch(uint32(prevLength-3), uint32(prevOffset-minOffsetSize))
// Insert in the hash table all strings up to the end of the match.
// index and index-1 are already inserted. If there is not enough
// lookahead, the last two strings are not inserted into the hash
// table.
newIndex := s.index + prevLength - 1
// Calculate missing hashes
end := newIndex
if end > s.maxInsertIndex {
end = s.maxInsertIndex
}
end += minMatchLength - 1
startindex := s.index + 1
if startindex > s.maxInsertIndex {
startindex = s.maxInsertIndex
}
tocheck := d.window[startindex:end]
dstSize := len(tocheck) - minMatchLength + 1
if dstSize > 0 {
dst := s.hashMatch[:dstSize]
bulkHash4(tocheck, dst)
var newH uint32
for i, val := range dst {
di := i + startindex
newH = val & hashMask
// Get previous value with the same hash.
// Our chain should point to the previous value.
s.hashPrev[di&windowMask] = s.hashHead[newH]
// Set the head of the hash chain to us.
s.hashHead[newH] = uint32(di + s.hashOffset)
}
s.hash = newH
}
s.index = newIndex
d.byteAvailable = false
s.length = minMatchLength - 1
if d.tokens.n == maxFlateBlockTokens {
// The block includes the current character
if d.err = d.writeBlock(&d.tokens, s.index, false); d.err != nil {
return
}
d.tokens.Reset()
}
s.ii = 0
} else {
// Reset, if we got a match this run.
if s.length >= minMatchLength {
s.ii = 0
}
// We have a byte waiting. Emit it.
if d.byteAvailable {
s.ii++
d.tokens.AddLiteral(d.window[s.index-1])
if d.tokens.n == maxFlateBlockTokens {
if d.err = d.writeBlock(&d.tokens, s.index, false); d.err != nil {
return
}
d.tokens.Reset()
}
s.index++
// If we have a long run of no matches, skip additional bytes
// Resets when s.ii overflows after 64KB.
if n := int(s.ii) - d.chain; n > 0 {
n = 1 + int(n>>6)
for j := 0; j < n; j++ {
if s.index >= d.windowEnd-1 {
break
}
d.tokens.AddLiteral(d.window[s.index-1])
if d.tokens.n == maxFlateBlockTokens {
if d.err = d.writeBlock(&d.tokens, s.index, false); d.err != nil {
return
}
d.tokens.Reset()
}
// Index...
if s.index < s.maxInsertIndex {
h := hash4(d.window[s.index:])
ch := s.hashHead[h]
s.chainHead = int(ch)
s.hashPrev[s.index&windowMask] = ch
s.hashHead[h] = uint32(s.index + s.hashOffset)
}
s.index++
}
// Flush last byte
d.tokens.AddLiteral(d.window[s.index-1])
d.byteAvailable = false
// s.length = minMatchLength - 1 // not needed, since s.ii is reset above, so it should never be > minMatchLength
if d.tokens.n == maxFlateBlockTokens {
if d.err = d.writeBlock(&d.tokens, s.index, false); d.err != nil {
return
}
d.tokens.Reset()
}
}
} else {
s.index++
d.byteAvailable = true
}
}
}
}
func (d *compressor) store() {
if d.windowEnd > 0 && (d.windowEnd == maxStoreBlockSize || d.sync) {
d.err = d.writeStoredBlock(d.window[:d.windowEnd])
d.windowEnd = 0
}
}
// fillWindow will fill the buffer with data for huffman-only compression.
// The number of bytes copied is returned.
func (d *compressor) fillBlock(b []byte) int {
n := copy(d.window[d.windowEnd:], b)
d.windowEnd += n
return n
}
// storeHuff will compress and store the currently added data,
// if enough has been accumulated or we at the end of the stream.
// Any error that occurred will be in d.err
func (d *compressor) storeHuff() {
if d.windowEnd < len(d.window) && !d.sync || d.windowEnd == 0 {
return
}
d.w.writeBlockHuff(false, d.window[:d.windowEnd], d.sync)
d.err = d.w.err
d.windowEnd = 0
}
// storeFast will compress and store the currently added data,
// if enough has been accumulated or we at the end of the stream.
// Any error that occurred will be in d.err
func (d *compressor) storeFast() {
// We only compress if we have maxStoreBlockSize.
if d.windowEnd < len(d.window) {
if !d.sync {
return
}
// Handle extremely small sizes.
if d.windowEnd < 128 {
if d.windowEnd == 0 {
return
}
if d.windowEnd <= 32 {
d.err = d.writeStoredBlock(d.window[:d.windowEnd])
} else {
d.w.writeBlockHuff(false, d.window[:d.windowEnd], true)
d.err = d.w.err
}
d.tokens.Reset()
d.windowEnd = 0
d.fast.Reset()
return
}
}
d.fast.Encode(&d.tokens, d.window[:d.windowEnd])
// If we made zero matches, store the block as is.
if d.tokens.n == 0 {
d.err = d.writeStoredBlock(d.window[:d.windowEnd])
// If we removed less than 1/16th, huffman compress the block.
} else if int(d.tokens.n) > d.windowEnd-(d.windowEnd>>4) {
d.w.writeBlockHuff(false, d.window[:d.windowEnd], d.sync)
d.err = d.w.err
} else {
d.w.writeBlockDynamic(&d.tokens, false, d.window[:d.windowEnd], d.sync)
d.err = d.w.err
}
d.tokens.Reset()
d.windowEnd = 0
}
// write will add input byte to the stream.
// Unless an error occurs all bytes will be consumed.
func (d *compressor) write(b []byte) (n int, err error) {
if d.err != nil {
return 0, d.err
}
n = len(b)
for len(b) > 0 {
if d.windowEnd == len(d.window) || d.sync {
d.step(d)
}
b = b[d.fill(d, b):]
if d.err != nil {
return 0, d.err
}
}
return n, d.err
}
func (d *compressor) syncFlush() error {
d.sync = true
if d.err != nil {
return d.err
}
d.step(d)
if d.err == nil {
d.w.writeStoredHeader(0, false)
d.w.flush()
d.err = d.w.err
}
d.sync = false
return d.err
}
func (d *compressor) init(w io.Writer, level int) (err error) {
d.w = newHuffmanBitWriter(w)
switch {
case level == NoCompression:
d.window = make([]byte, maxStoreBlockSize)
d.fill = (*compressor).fillBlock
d.step = (*compressor).store
case level == ConstantCompression:
d.w.logNewTablePenalty = 10
d.window = make([]byte, 32<<10)
d.fill = (*compressor).fillBlock
d.step = (*compressor).storeHuff
case level == DefaultCompression:
level = 5
fallthrough
case level >= 1 && level <= 6:
d.w.logNewTablePenalty = 7
d.fast = newFastEnc(level)
d.window = make([]byte, maxStoreBlockSize)
d.fill = (*compressor).fillBlock
d.step = (*compressor).storeFast
case 7 <= level && level <= 9:
d.w.logNewTablePenalty = 8
d.state = &advancedState{}
d.compressionLevel = levels[level]
d.initDeflate()
d.fill = (*compressor).fillDeflate
d.step = (*compressor).deflateLazy
default:
return fmt.Errorf("flate: invalid compression level %d: want value in range [-2, 9]", level)
}
d.level = level
return nil
}
// reset the state of the compressor.
func (d *compressor) reset(w io.Writer) {
d.w.reset(w)
d.sync = false
d.err = nil
// We only need to reset a few things for Snappy.
if d.fast != nil {
d.fast.Reset()
d.windowEnd = 0
d.tokens.Reset()
return
}
switch d.compressionLevel.chain {
case 0:
// level was NoCompression or ConstantCompresssion.
d.windowEnd = 0
default:
s := d.state
s.chainHead = -1
for i := range s.hashHead {
s.hashHead[i] = 0
}
for i := range s.hashPrev {
s.hashPrev[i] = 0
}
s.hashOffset = 1
s.index, d.windowEnd = 0, 0
d.blockStart, d.byteAvailable = 0, false
d.tokens.Reset()
s.length = minMatchLength - 1
s.offset = 0
s.hash = 0
s.ii = 0
s.maxInsertIndex = 0
}
}
func (d *compressor) close() error {
if d.err != nil {
return d.err
}
d.sync = true
d.step(d)
if d.err != nil {
return d.err
}
if d.w.writeStoredHeader(0, true); d.w.err != nil {
return d.w.err
}
d.w.flush()
d.w.reset(nil)
return d.w.err
}
// NewWriter returns a new Writer compressing data at the given level.
// Following zlib, levels range from 1 (BestSpeed) to 9 (BestCompression);
// higher levels typically run slower but compress more.
// Level 0 (NoCompression) does not attempt any compression; it only adds the
// necessary DEFLATE framing.
// Level -1 (DefaultCompression) uses the default compression level.
// Level -2 (ConstantCompression) will use Huffman compression only, giving
// a very fast compression for all types of input, but sacrificing considerable
// compression efficiency.
//
// If level is in the range [-2, 9] then the error returned will be nil.
// Otherwise the error returned will be non-nil.
func NewWriter(w io.Writer, level int) (*Writer, error) {
var dw Writer
if err := dw.d.init(w, level); err != nil {
return nil, err
}
return &dw, nil
}
// NewWriterDict is like NewWriter but initializes the new
// Writer with a preset dictionary. The returned Writer behaves
// as if the dictionary had been written to it without producing
// any compressed output. The compressed data written to w
// can only be decompressed by a Reader initialized with the
// same dictionary.
func NewWriterDict(w io.Writer, level int, dict []byte) (*Writer, error) {
zw, err := NewWriter(w, level)
if err != nil {
return nil, err
}
zw.d.fillWindow(dict)
zw.dict = append(zw.dict, dict...) // duplicate dictionary for Reset method.
return zw, err
}
// A Writer takes data written to it and writes the compressed
// form of that data to an underlying writer (see NewWriter).
type Writer struct {
d compressor
dict []byte
}
// Write writes data to w, which will eventually write the
// compressed form of data to its underlying writer.
func (w *Writer) Write(data []byte) (n int, err error) {
return w.d.write(data)
}
// Flush flushes any pending data to the underlying writer.
// It is useful mainly in compressed network protocols, to ensure that
// a remote reader has enough data to reconstruct a packet.
// Flush does not return until the data has been written.
// Calling Flush when there is no pending data still causes the Writer
// to emit a sync marker of at least 4 bytes.
// If the underlying writer returns an error, Flush returns that error.
//
// In the terminology of the zlib library, Flush is equivalent to Z_SYNC_FLUSH.
func (w *Writer) Flush() error {
// For more about flushing:
// http://www.bolet.org/~pornin/deflate-flush.html
return w.d.syncFlush()
}
// Close flushes and closes the writer.
func (w *Writer) Close() error {
return w.d.close()
}
// Reset discards the writer's state and makes it equivalent to
// the result of NewWriter or NewWriterDict called with dst
// and w's level and dictionary.
func (w *Writer) Reset(dst io.Writer) {
if len(w.dict) > 0 {
// w was created with NewWriterDict
w.d.reset(dst)
if dst != nil {
w.d.fillWindow(w.dict)
}
} else {
// w was created with NewWriter
w.d.reset(dst)
}
}
// ResetDict discards the writer's state and makes it equivalent to
// the result of NewWriter or NewWriterDict called with dst
// and w's level, but sets a specific dictionary.
func (w *Writer) ResetDict(dst io.Writer, dict []byte) {
w.dict = dict
w.d.reset(dst)
w.d.fillWindow(w.dict)
}

184
src/cmd/linuxkit/vendor/github.com/klauspost/compress/flate/dict_decoder.go generated vendored Normal file
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// Copyright 2016 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 flate
// dictDecoder implements the LZ77 sliding dictionary as used in decompression.
// LZ77 decompresses data through sequences of two forms of commands:
//
// * Literal insertions: Runs of one or more symbols are inserted into the data
// stream as is. This is accomplished through the writeByte method for a
// single symbol, or combinations of writeSlice/writeMark for multiple symbols.
// Any valid stream must start with a literal insertion if no preset dictionary
// is used.
//
// * Backward copies: Runs of one or more symbols are copied from previously
// emitted data. Backward copies come as the tuple (dist, length) where dist
// determines how far back in the stream to copy from and length determines how
// many bytes to copy. Note that it is valid for the length to be greater than
// the distance. Since LZ77 uses forward copies, that situation is used to
// perform a form of run-length encoding on repeated runs of symbols.
// The writeCopy and tryWriteCopy are used to implement this command.
//
// For performance reasons, this implementation performs little to no sanity
// checks about the arguments. As such, the invariants documented for each
// method call must be respected.
type dictDecoder struct {
hist []byte // Sliding window history
// Invariant: 0 <= rdPos <= wrPos <= len(hist)
wrPos int // Current output position in buffer
rdPos int // Have emitted hist[:rdPos] already
full bool // Has a full window length been written yet?
}
// init initializes dictDecoder to have a sliding window dictionary of the given
// size. If a preset dict is provided, it will initialize the dictionary with
// the contents of dict.
func (dd *dictDecoder) init(size int, dict []byte) {
*dd = dictDecoder{hist: dd.hist}
if cap(dd.hist) < size {
dd.hist = make([]byte, size)
}
dd.hist = dd.hist[:size]
if len(dict) > len(dd.hist) {
dict = dict[len(dict)-len(dd.hist):]
}
dd.wrPos = copy(dd.hist, dict)
if dd.wrPos == len(dd.hist) {
dd.wrPos = 0
dd.full = true
}
dd.rdPos = dd.wrPos
}
// histSize reports the total amount of historical data in the dictionary.
func (dd *dictDecoder) histSize() int {
if dd.full {
return len(dd.hist)
}
return dd.wrPos
}
// availRead reports the number of bytes that can be flushed by readFlush.
func (dd *dictDecoder) availRead() int {
return dd.wrPos - dd.rdPos
}
// availWrite reports the available amount of output buffer space.
func (dd *dictDecoder) availWrite() int {
return len(dd.hist) - dd.wrPos
}
// writeSlice returns a slice of the available buffer to write data to.
//
// This invariant will be kept: len(s) <= availWrite()
func (dd *dictDecoder) writeSlice() []byte {
return dd.hist[dd.wrPos:]
}
// writeMark advances the writer pointer by cnt.
//
// This invariant must be kept: 0 <= cnt <= availWrite()
func (dd *dictDecoder) writeMark(cnt int) {
dd.wrPos += cnt
}
// writeByte writes a single byte to the dictionary.
//
// This invariant must be kept: 0 < availWrite()
func (dd *dictDecoder) writeByte(c byte) {
dd.hist[dd.wrPos] = c
dd.wrPos++
}
// writeCopy copies a string at a given (dist, length) to the output.
// This returns the number of bytes copied and may be less than the requested
// length if the available space in the output buffer is too small.
//
// This invariant must be kept: 0 < dist <= histSize()
func (dd *dictDecoder) writeCopy(dist, length int) int {
dstBase := dd.wrPos
dstPos := dstBase
srcPos := dstPos - dist
endPos := dstPos + length
if endPos > len(dd.hist) {
endPos = len(dd.hist)
}
// Copy non-overlapping section after destination position.
//
// This section is non-overlapping in that the copy length for this section
// is always less than or equal to the backwards distance. This can occur
// if a distance refers to data that wraps-around in the buffer.
// Thus, a backwards copy is performed here; that is, the exact bytes in
// the source prior to the copy is placed in the destination.
if srcPos < 0 {
srcPos += len(dd.hist)
dstPos += copy(dd.hist[dstPos:endPos], dd.hist[srcPos:])
srcPos = 0
}
// Copy possibly overlapping section before destination position.
//
// This section can overlap if the copy length for this section is larger
// than the backwards distance. This is allowed by LZ77 so that repeated
// strings can be succinctly represented using (dist, length) pairs.
// Thus, a forwards copy is performed here; that is, the bytes copied is
// possibly dependent on the resulting bytes in the destination as the copy
// progresses along. This is functionally equivalent to the following:
//
// for i := 0; i < endPos-dstPos; i++ {
// dd.hist[dstPos+i] = dd.hist[srcPos+i]
// }
// dstPos = endPos
//
for dstPos < endPos {
dstPos += copy(dd.hist[dstPos:endPos], dd.hist[srcPos:dstPos])
}
dd.wrPos = dstPos
return dstPos - dstBase
}
// tryWriteCopy tries to copy a string at a given (distance, length) to the
// output. This specialized version is optimized for short distances.
//
// This method is designed to be inlined for performance reasons.
//
// This invariant must be kept: 0 < dist <= histSize()
func (dd *dictDecoder) tryWriteCopy(dist, length int) int {
dstPos := dd.wrPos
endPos := dstPos + length
if dstPos < dist || endPos > len(dd.hist) {
return 0
}
dstBase := dstPos
srcPos := dstPos - dist
// Copy possibly overlapping section before destination position.
loop:
dstPos += copy(dd.hist[dstPos:endPos], dd.hist[srcPos:dstPos])
if dstPos < endPos {
goto loop // Avoid for-loop so that this function can be inlined
}
dd.wrPos = dstPos
return dstPos - dstBase
}
// readFlush returns a slice of the historical buffer that is ready to be
// emitted to the user. The data returned by readFlush must be fully consumed
// before calling any other dictDecoder methods.
func (dd *dictDecoder) readFlush() []byte {
toRead := dd.hist[dd.rdPos:dd.wrPos]
dd.rdPos = dd.wrPos
if dd.wrPos == len(dd.hist) {
dd.wrPos, dd.rdPos = 0, 0
dd.full = true
}
return toRead
}

233
src/cmd/linuxkit/vendor/github.com/klauspost/compress/flate/fast_encoder.go generated vendored Normal file
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// Copyright 2011 The Snappy-Go Authors. All rights reserved.
// Modified for deflate by Klaus Post (c) 2015.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package flate
import (
"encoding/binary"
"fmt"
"math/bits"
)
type fastEnc interface {
Encode(dst *tokens, src []byte)
Reset()
}
func newFastEnc(level int) fastEnc {
switch level {
case 1:
return &fastEncL1{fastGen: fastGen{cur: maxStoreBlockSize}}
case 2:
return &fastEncL2{fastGen: fastGen{cur: maxStoreBlockSize}}
case 3:
return &fastEncL3{fastGen: fastGen{cur: maxStoreBlockSize}}
case 4:
return &fastEncL4{fastGen: fastGen{cur: maxStoreBlockSize}}
case 5:
return &fastEncL5{fastGen: fastGen{cur: maxStoreBlockSize}}
case 6:
return &fastEncL6{fastGen: fastGen{cur: maxStoreBlockSize}}
default:
panic("invalid level specified")
}
}
const (
tableBits = 15 // Bits used in the table
tableSize = 1 << tableBits // Size of the table
tableShift = 32 - tableBits // Right-shift to get the tableBits most significant bits of a uint32.
baseMatchOffset = 1 // The smallest match offset
baseMatchLength = 3 // The smallest match length per the RFC section 3.2.5
maxMatchOffset = 1 << 15 // The largest match offset
bTableBits = 17 // Bits used in the big tables
bTableSize = 1 << bTableBits // Size of the table
allocHistory = maxStoreBlockSize * 5 // Size to preallocate for history.
bufferReset = (1 << 31) - allocHistory - maxStoreBlockSize - 1 // Reset the buffer offset when reaching this.
)
const (
prime3bytes = 506832829
prime4bytes = 2654435761
prime5bytes = 889523592379
prime6bytes = 227718039650203
prime7bytes = 58295818150454627
prime8bytes = 0xcf1bbcdcb7a56463
)
func load32(b []byte, i int) uint32 {
// Help the compiler eliminate bounds checks on the read so it can be done in a single read.
b = b[i:]
b = b[:4]
return uint32(b[0]) | uint32(b[1])<<8 | uint32(b[2])<<16 | uint32(b[3])<<24
}
func load64(b []byte, i int) uint64 {
return binary.LittleEndian.Uint64(b[i:])
}
func load3232(b []byte, i int32) uint32 {
return binary.LittleEndian.Uint32(b[i:])
}
func load6432(b []byte, i int32) uint64 {
return binary.LittleEndian.Uint64(b[i:])
}
func hash(u uint32) uint32 {
return (u * 0x1e35a7bd) >> tableShift
}
type tableEntry struct {
offset int32
}
// fastGen maintains the table for matches,
// and the previous byte block for level 2.
// This is the generic implementation.
type fastGen struct {
hist []byte
cur int32
}
func (e *fastGen) addBlock(src []byte) int32 {
// check if we have space already
if len(e.hist)+len(src) > cap(e.hist) {
if cap(e.hist) == 0 {
e.hist = make([]byte, 0, allocHistory)
} else {
if cap(e.hist) < maxMatchOffset*2 {
panic("unexpected buffer size")
}
// Move down
offset := int32(len(e.hist)) - maxMatchOffset
copy(e.hist[0:maxMatchOffset], e.hist[offset:])
e.cur += offset
e.hist = e.hist[:maxMatchOffset]
}
}
s := int32(len(e.hist))
e.hist = append(e.hist, src...)
return s
}
// hash4 returns the hash of u to fit in a hash table with h bits.
// Preferably h should be a constant and should always be <32.
func hash4u(u uint32, h uint8) uint32 {
return (u * prime4bytes) >> ((32 - h) & reg8SizeMask32)
}
type tableEntryPrev struct {
Cur tableEntry
Prev tableEntry
}
// hash4x64 returns the hash of the lowest 4 bytes of u to fit in a hash table with h bits.
// Preferably h should be a constant and should always be <32.
func hash4x64(u uint64, h uint8) uint32 {
return (uint32(u) * prime4bytes) >> ((32 - h) & reg8SizeMask32)
}
// hash7 returns the hash of the lowest 7 bytes of u to fit in a hash table with h bits.
// Preferably h should be a constant and should always be <64.
func hash7(u uint64, h uint8) uint32 {
return uint32(((u << (64 - 56)) * prime7bytes) >> ((64 - h) & reg8SizeMask64))
}
// hash8 returns the hash of u to fit in a hash table with h bits.
// Preferably h should be a constant and should always be <64.
func hash8(u uint64, h uint8) uint32 {
return uint32((u * prime8bytes) >> ((64 - h) & reg8SizeMask64))
}
// hash6 returns the hash of the lowest 6 bytes of u to fit in a hash table with h bits.
// Preferably h should be a constant and should always be <64.
func hash6(u uint64, h uint8) uint32 {
return uint32(((u << (64 - 48)) * prime6bytes) >> ((64 - h) & reg8SizeMask64))
}
// matchlen will return the match length between offsets and t in src.
// The maximum length returned is maxMatchLength - 4.
// It is assumed that s > t, that t >=0 and s < len(src).
func (e *fastGen) matchlen(s, t int32, src []byte) int32 {
if debugDecode {
if t >= s {
panic(fmt.Sprint("t >=s:", t, s))
}
if int(s) >= len(src) {
panic(fmt.Sprint("s >= len(src):", s, len(src)))
}
if t < 0 {
panic(fmt.Sprint("t < 0:", t))
}
if s-t > maxMatchOffset {
panic(fmt.Sprint(s, "-", t, "(", s-t, ") > maxMatchLength (", maxMatchOffset, ")"))
}
}
s1 := int(s) + maxMatchLength - 4
if s1 > len(src) {
s1 = len(src)
}
// Extend the match to be as long as possible.
return int32(matchLen(src[s:s1], src[t:]))
}
// 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 debugDeflate {
if t >= s {
panic(fmt.Sprint("t >=s:", t, s))
}
if int(s) >= len(src) {
panic(fmt.Sprint("s >= len(src):", s, len(src)))
}
if t < 0 {
panic(fmt.Sprint("t < 0:", t))
}
if s-t > maxMatchOffset {
panic(fmt.Sprint(s, "-", t, "(", s-t, ") > maxMatchLength (", maxMatchOffset, ")"))
}
}
// Extend the match to be as long as possible.
return int32(matchLen(src[s:], src[t:]))
}
// Reset the encoding table.
func (e *fastGen) Reset() {
if cap(e.hist) < allocHistory {
e.hist = make([]byte, 0, allocHistory)
}
// We offset current position so everything will be out of reach.
// If we are above the buffer reset it will be cleared anyway since len(hist) == 0.
if e.cur <= bufferReset {
e.cur += maxMatchOffset + int32(len(e.hist))
}
e.hist = e.hist[:0]
}
// matchLen returns the maximum length.
// 'a' must be the shortest of the two.
func matchLen(a, b []byte) int {
var checked int
for len(a) >= 8 {
if diff := binary.LittleEndian.Uint64(a) ^ binary.LittleEndian.Uint64(b); diff != 0 {
return checked + (bits.TrailingZeros64(diff) >> 3)
}
checked += 8
a = a[8:]
b = b[8:]
}
b = b[:len(a)]
for i := range a {
if a[i] != b[i] {
return i + checked
}
}
return len(a) + checked
}

1191
src/cmd/linuxkit/vendor/github.com/klauspost/compress/flate/huffman_bit_writer.go generated vendored Normal file
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384
src/cmd/linuxkit/vendor/github.com/klauspost/compress/flate/huffman_code.go generated vendored Normal file
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// 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 flate
import (
"math"
"math/bits"
)
const (
maxBitsLimit = 16
// number of valid literals
literalCount = 286
)
// hcode is a huffman code with a bit code and bit length.
type hcode struct {
code uint16
len uint8
}
type huffmanEncoder struct {
codes []hcode
bitCount [17]int32
// Allocate a reusable buffer with the longest possible frequency table.
// Possible lengths are codegenCodeCount, offsetCodeCount and literalCount.
// The largest of these is literalCount, so we allocate for that case.
freqcache [literalCount + 1]literalNode
}
type literalNode struct {
literal uint16
freq uint16
}
// A levelInfo describes the state of the constructed tree for a given depth.
type levelInfo struct {
// Our level. for better printing
level int32
// The frequency of the last node at this level
lastFreq int32
// The frequency of the next character to add to this level
nextCharFreq int32
// The frequency of the next pair (from level below) to add to this level.
// Only valid if the "needed" value of the next lower level is 0.
nextPairFreq int32
// The number of chains remaining to generate for this level before moving
// up to the next level
needed int32
}
// set sets the code and length of an hcode.
func (h *hcode) set(code uint16, length uint8) {
h.len = length
h.code = code
}
func reverseBits(number uint16, bitLength byte) uint16 {
return bits.Reverse16(number << ((16 - bitLength) & 15))
}
func maxNode() literalNode { return literalNode{math.MaxUint16, math.MaxUint16} }
func newHuffmanEncoder(size int) *huffmanEncoder {
// Make capacity to next power of two.
c := uint(bits.Len32(uint32(size - 1)))
return &huffmanEncoder{codes: make([]hcode, size, 1<<c)}
}
// Generates a HuffmanCode corresponding to the fixed literal table
func generateFixedLiteralEncoding() *huffmanEncoder {
h := newHuffmanEncoder(literalCount)
codes := h.codes
var ch uint16
for ch = 0; ch < literalCount; ch++ {
var bits uint16
var size uint8
switch {
case ch < 144:
// size 8, 000110000 .. 10111111
bits = ch + 48
size = 8
case ch < 256:
// size 9, 110010000 .. 111111111
bits = ch + 400 - 144
size = 9
case ch < 280:
// size 7, 0000000 .. 0010111
bits = ch - 256
size = 7
default:
// size 8, 11000000 .. 11000111
bits = ch + 192 - 280
size = 8
}
codes[ch] = hcode{code: reverseBits(bits, size), len: size}
}
return h
}
func generateFixedOffsetEncoding() *huffmanEncoder {
h := newHuffmanEncoder(30)
codes := h.codes
for ch := range codes {
codes[ch] = hcode{code: reverseBits(uint16(ch), 5), len: 5}
}
return h
}
var fixedLiteralEncoding = generateFixedLiteralEncoding()
var fixedOffsetEncoding = generateFixedOffsetEncoding()
func (h *huffmanEncoder) bitLength(freq []uint16) int {
var total int
for i, f := range freq {
if f != 0 {
total += int(f) * int(h.codes[i].len)
}
}
return total
}
func (h *huffmanEncoder) bitLengthRaw(b []byte) int {
var total int
for _, f := range b {
total += int(h.codes[f].len)
}
return total
}
// canReuseBits returns the number of bits or math.MaxInt32 if the encoder cannot be reused.
func (h *huffmanEncoder) canReuseBits(freq []uint16) int {
var total int
for i, f := range freq {
if f != 0 {
code := h.codes[i]
if code.len == 0 {
return math.MaxInt32
}
total += int(f) * int(code.len)
}
}
return total
}
// Return the number of literals assigned to each bit size in the Huffman encoding
//
// This method is only called when list.length >= 3
// The cases of 0, 1, and 2 literals are handled by special case code.
//
// list An array of the literals with non-zero frequencies
// and their associated frequencies. The array is in order of increasing
// frequency, and has as its last element a special element with frequency
// MaxInt32
// maxBits The maximum number of bits that should be used to encode any literal.
// Must be less than 16.
// return An integer array in which array[i] indicates the number of literals
// that should be encoded in i bits.
func (h *huffmanEncoder) bitCounts(list []literalNode, maxBits int32) []int32 {
if maxBits >= maxBitsLimit {
panic("flate: maxBits too large")
}
n := int32(len(list))
list = list[0 : n+1]
list[n] = maxNode()
// The tree can't have greater depth than n - 1, no matter what. This
// saves a little bit of work in some small cases
if maxBits > n-1 {
maxBits = n - 1
}
// Create information about each of the levels.
// A bogus "Level 0" whose sole purpose is so that
// level1.prev.needed==0. This makes level1.nextPairFreq
// be a legitimate value that never gets chosen.
var levels [maxBitsLimit]levelInfo
// leafCounts[i] counts the number of literals at the left
// of ancestors of the rightmost node at level i.
// leafCounts[i][j] is the number of literals at the left
// 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: l1f,
nextCharFreq: l2f,
nextPairFreq: l0f,
}
leafCounts[level][level] = 2
if level == 1 {
levels[level].nextPairFreq = math.MaxInt32
}
}
// We need a total of 2*n - 2 items at top level and have already generated 2.
levels[maxBits].needed = 2*n - 4
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.
// End all calculations for this level.
// To make sure we never come back to this level or any lower level,
// set nextPairFreq impossibly large.
l.needed = 0
levels[level+1].nextPairFreq = math.MaxInt32
level++
continue
}
prevFreq := l.lastFreq
if l.nextCharFreq < l.nextPairFreq {
// The next item on this row is a leaf node.
n := leafCounts[level][level] + 1
l.lastFreq = l.nextCharFreq
// Lower leafCounts are the same of the previous node.
leafCounts[level][level] = n
e := list[n]
if e.literal < math.MaxUint16 {
l.nextCharFreq = int32(e.freq)
} else {
l.nextCharFreq = math.MaxInt32
}
} else {
// The next item on this row is a pair from the previous row.
// nextPairFreq isn't valid until we generate two
// more values in the level below
l.lastFreq = l.nextPairFreq
// Take leaf counts from the lower level, except counts[level] remains the same.
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
}
if l.needed--; l.needed == 0 {
// We've done everything we need to do for this level.
// Continue calculating one level up. Fill in nextPairFreq
// of that level with the sum of the two nodes we've just calculated on
// this level.
if l.level == maxBits {
// All done!
break
}
levels[l.level+1].nextPairFreq = prevFreq + l.lastFreq
level++
} else {
// If we stole from below, move down temporarily to replenish it.
for levels[level-1].needed > 0 {
level--
}
}
}
// Somethings is wrong if at the end, the top level is null or hasn't used
// all of the leaves.
if leafCounts[maxBits][maxBits] != n {
panic("leafCounts[maxBits][maxBits] != n")
}
bitCount := h.bitCount[:maxBits+1]
bits := 1
counts := &leafCounts[maxBits]
for level := maxBits; level > 0; level-- {
// chain.leafCount gives the number of literals requiring at least "bits"
// bits to encode.
bitCount[bits] = counts[level] - counts[level-1]
bits++
}
return bitCount
}
// Look at the leaves and assign them a bit count and an encoding as specified
// in RFC 1951 3.2.2
func (h *huffmanEncoder) assignEncodingAndSize(bitCount []int32, list []literalNode) {
code := uint16(0)
for n, bits := range bitCount {
code <<= 1
if n == 0 || bits == 0 {
continue
}
// The literals list[len(list)-bits] .. list[len(list)-bits]
// are encoded using "bits" bits, and get the values
// code, code + 1, .... The code values are
// assigned in literal order (not frequency order).
chunk := list[len(list)-int(bits):]
sortByLiteral(chunk)
for _, node := range chunk {
h.codes[node.literal] = hcode{code: reverseBits(code, uint8(n)), len: uint8(n)}
code++
}
list = list[0 : len(list)-int(bits)]
}
}
// Update this Huffman Code object to be the minimum code for the specified frequency count.
//
// 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 []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
for i, f := range freq {
if f != 0 {
list[count] = literalNode{uint16(i), f}
count++
} else {
codes[i].len = 0
}
}
list[count] = 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.codes[node.literal].set(uint16(i), 1)
}
return
}
sortByFreq(list)
// Get the number of literals for each bit count
bitCount := h.bitCounts(list, maxBits)
// And do the assignment
h.assignEncodingAndSize(bitCount, list)
}
// atLeastOne clamps the result between 1 and 15.
func atLeastOne(v float32) float32 {
if v < 1 {
return 1
}
if v > 15 {
return 15
}
return v
}
// Unassigned values are assigned '1' in the histogram.
func fillHist(b []uint16) {
for i, v := range b {
if v == 0 {
b[i] = 1
}
}
}
func histogram(b []byte, h []uint16, fill bool) {
h = h[:256]
for _, t := range b {
h[t]++
}
if fill {
fillHist(h)
}
}

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src/cmd/linuxkit/vendor/github.com/klauspost/compress/flate/huffman_sortByFreq.go generated vendored Normal file
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// 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 flate
// Sort sorts data.
// It makes one call to data.Len to determine n, and O(n*log(n)) calls to
// data.Less and data.Swap. The sort is not guaranteed to be stable.
func sortByFreq(data []literalNode) {
n := len(data)
quickSortByFreq(data, 0, n, maxDepth(n))
}
func quickSortByFreq(data []literalNode, a, b, maxDepth int) {
for b-a > 12 { // Use ShellSort for slices <= 12 elements
if maxDepth == 0 {
heapSort(data, a, b)
return
}
maxDepth--
mlo, mhi := doPivotByFreq(data, a, b)
// Avoiding recursion on the larger subproblem guarantees
// a stack depth of at most lg(b-a).
if mlo-a < b-mhi {
quickSortByFreq(data, a, mlo, maxDepth)
a = mhi // i.e., quickSortByFreq(data, mhi, b)
} else {
quickSortByFreq(data, mhi, b, maxDepth)
b = mlo // i.e., quickSortByFreq(data, a, mlo)
}
}
if b-a > 1 {
// Do ShellSort pass with gap 6
// It could be written in this simplified form cause b-a <= 12
for i := a + 6; i < b; i++ {
if data[i].freq == data[i-6].freq && data[i].literal < data[i-6].literal || data[i].freq < data[i-6].freq {
data[i], data[i-6] = data[i-6], data[i]
}
}
insertionSortByFreq(data, a, b)
}
}
// siftDownByFreq implements the heap property on data[lo, hi).
// first is an offset into the array where the root of the heap lies.
func siftDownByFreq(data []literalNode, lo, hi, first int) {
root := lo
for {
child := 2*root + 1
if child >= hi {
break
}
if child+1 < hi && (data[first+child].freq == data[first+child+1].freq && data[first+child].literal < data[first+child+1].literal || data[first+child].freq < data[first+child+1].freq) {
child++
}
if data[first+root].freq == data[first+child].freq && data[first+root].literal > data[first+child].literal || data[first+root].freq > data[first+child].freq {
return
}
data[first+root], data[first+child] = data[first+child], data[first+root]
root = child
}
}
func doPivotByFreq(data []literalNode, lo, hi int) (midlo, midhi int) {
m := int(uint(lo+hi) >> 1) // Written like this to avoid integer overflow.
if hi-lo > 40 {
// Tukey's ``Ninther,'' median of three medians of three.
s := (hi - lo) / 8
medianOfThreeSortByFreq(data, lo, lo+s, lo+2*s)
medianOfThreeSortByFreq(data, m, m-s, m+s)
medianOfThreeSortByFreq(data, hi-1, hi-1-s, hi-1-2*s)
}
medianOfThreeSortByFreq(data, lo, m, hi-1)
// Invariants are:
// data[lo] = pivot (set up by ChoosePivot)
// data[lo < i < a] < pivot
// data[a <= i < b] <= pivot
// data[b <= i < c] unexamined
// data[c <= i < hi-1] > pivot
// data[hi-1] >= pivot
pivot := lo
a, c := lo+1, hi-1
for ; a < c && (data[a].freq == data[pivot].freq && data[a].literal < data[pivot].literal || data[a].freq < data[pivot].freq); a++ {
}
b := a
for {
for ; b < c && (data[pivot].freq == data[b].freq && data[pivot].literal > data[b].literal || data[pivot].freq > data[b].freq); b++ { // data[b] <= pivot
}
for ; b < c && (data[pivot].freq == data[c-1].freq && data[pivot].literal < data[c-1].literal || data[pivot].freq < data[c-1].freq); c-- { // data[c-1] > pivot
}
if b >= c {
break
}
// data[b] > pivot; data[c-1] <= pivot
data[b], data[c-1] = data[c-1], data[b]
b++
c--
}
// If hi-c<3 then there are duplicates (by property of median of nine).
// Let's be a bit more conservative, and set border to 5.
protect := hi-c < 5
if !protect && hi-c < (hi-lo)/4 {
// Lets test some points for equality to pivot
dups := 0
if data[pivot].freq == data[hi-1].freq && data[pivot].literal > data[hi-1].literal || data[pivot].freq > data[hi-1].freq { // data[hi-1] = pivot
data[c], data[hi-1] = data[hi-1], data[c]
c++
dups++
}
if data[b-1].freq == data[pivot].freq && data[b-1].literal > data[pivot].literal || data[b-1].freq > data[pivot].freq { // data[b-1] = pivot
b--
dups++
}
// m-lo = (hi-lo)/2 > 6
// b-lo > (hi-lo)*3/4-1 > 8
// ==> m < b ==> data[m] <= pivot
if data[m].freq == data[pivot].freq && data[m].literal > data[pivot].literal || data[m].freq > data[pivot].freq { // data[m] = pivot
data[m], data[b-1] = data[b-1], data[m]
b--
dups++
}
// if at least 2 points are equal to pivot, assume skewed distribution
protect = dups > 1
}
if protect {
// Protect against a lot of duplicates
// Add invariant:
// data[a <= i < b] unexamined
// data[b <= i < c] = pivot
for {
for ; a < b && (data[b-1].freq == data[pivot].freq && data[b-1].literal > data[pivot].literal || data[b-1].freq > data[pivot].freq); b-- { // data[b] == pivot
}
for ; a < b && (data[a].freq == data[pivot].freq && data[a].literal < data[pivot].literal || data[a].freq < data[pivot].freq); a++ { // data[a] < pivot
}
if a >= b {
break
}
// data[a] == pivot; data[b-1] < pivot
data[a], data[b-1] = data[b-1], data[a]
a++
b--
}
}
// Swap pivot into middle
data[pivot], data[b-1] = data[b-1], data[pivot]
return b - 1, c
}
// Insertion sort
func insertionSortByFreq(data []literalNode, a, b int) {
for i := a + 1; i < b; i++ {
for j := i; j > a && (data[j].freq == data[j-1].freq && data[j].literal < data[j-1].literal || data[j].freq < data[j-1].freq); j-- {
data[j], data[j-1] = data[j-1], data[j]
}
}
}
// quickSortByFreq, loosely following Bentley and McIlroy,
// ``Engineering a Sort Function,'' SP&E November 1993.
// medianOfThreeSortByFreq moves the median of the three values data[m0], data[m1], data[m2] into data[m1].
func medianOfThreeSortByFreq(data []literalNode, m1, m0, m2 int) {
// sort 3 elements
if data[m1].freq == data[m0].freq && data[m1].literal < data[m0].literal || data[m1].freq < data[m0].freq {
data[m1], data[m0] = data[m0], data[m1]
}
// data[m0] <= data[m1]
if data[m2].freq == data[m1].freq && data[m2].literal < data[m1].literal || data[m2].freq < data[m1].freq {
data[m2], data[m1] = data[m1], data[m2]
// data[m0] <= data[m2] && data[m1] < data[m2]
if data[m1].freq == data[m0].freq && data[m1].literal < data[m0].literal || data[m1].freq < data[m0].freq {
data[m1], data[m0] = data[m0], data[m1]
}
}
// now data[m0] <= data[m1] <= data[m2]
}

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src/cmd/linuxkit/vendor/github.com/klauspost/compress/flate/huffman_sortByLiteral.go generated vendored Normal file
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// 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 flate
// Sort sorts data.
// It makes one call to data.Len to determine n, and O(n*log(n)) calls to
// data.Less and data.Swap. The sort is not guaranteed to be stable.
func sortByLiteral(data []literalNode) {
n := len(data)
quickSort(data, 0, n, maxDepth(n))
}
func quickSort(data []literalNode, a, b, maxDepth int) {
for b-a > 12 { // Use ShellSort for slices <= 12 elements
if maxDepth == 0 {
heapSort(data, a, b)
return
}
maxDepth--
mlo, mhi := doPivot(data, a, b)
// Avoiding recursion on the larger subproblem guarantees
// a stack depth of at most lg(b-a).
if mlo-a < b-mhi {
quickSort(data, a, mlo, maxDepth)
a = mhi // i.e., quickSort(data, mhi, b)
} else {
quickSort(data, mhi, b, maxDepth)
b = mlo // i.e., quickSort(data, a, mlo)
}
}
if b-a > 1 {
// Do ShellSort pass with gap 6
// It could be written in this simplified form cause b-a <= 12
for i := a + 6; i < b; i++ {
if data[i].literal < data[i-6].literal {
data[i], data[i-6] = data[i-6], data[i]
}
}
insertionSort(data, a, b)
}
}
func heapSort(data []literalNode, a, b int) {
first := a
lo := 0
hi := b - a
// Build heap with greatest element at top.
for i := (hi - 1) / 2; i >= 0; i-- {
siftDown(data, i, hi, first)
}
// Pop elements, largest first, into end of data.
for i := hi - 1; i >= 0; i-- {
data[first], data[first+i] = data[first+i], data[first]
siftDown(data, lo, i, first)
}
}
// siftDown implements the heap property on data[lo, hi).
// first is an offset into the array where the root of the heap lies.
func siftDown(data []literalNode, lo, hi, first int) {
root := lo
for {
child := 2*root + 1
if child >= hi {
break
}
if child+1 < hi && data[first+child].literal < data[first+child+1].literal {
child++
}
if data[first+root].literal > data[first+child].literal {
return
}
data[first+root], data[first+child] = data[first+child], data[first+root]
root = child
}
}
func doPivot(data []literalNode, lo, hi int) (midlo, midhi int) {
m := int(uint(lo+hi) >> 1) // Written like this to avoid integer overflow.
if hi-lo > 40 {
// Tukey's ``Ninther,'' median of three medians of three.
s := (hi - lo) / 8
medianOfThree(data, lo, lo+s, lo+2*s)
medianOfThree(data, m, m-s, m+s)
medianOfThree(data, hi-1, hi-1-s, hi-1-2*s)
}
medianOfThree(data, lo, m, hi-1)
// Invariants are:
// data[lo] = pivot (set up by ChoosePivot)
// data[lo < i < a] < pivot
// data[a <= i < b] <= pivot
// data[b <= i < c] unexamined
// data[c <= i < hi-1] > pivot
// data[hi-1] >= pivot
pivot := lo
a, c := lo+1, hi-1
for ; a < c && data[a].literal < data[pivot].literal; a++ {
}
b := a
for {
for ; b < c && data[pivot].literal > data[b].literal; b++ { // data[b] <= pivot
}
for ; b < c && data[pivot].literal < data[c-1].literal; c-- { // data[c-1] > pivot
}
if b >= c {
break
}
// data[b] > pivot; data[c-1] <= pivot
data[b], data[c-1] = data[c-1], data[b]
b++
c--
}
// If hi-c<3 then there are duplicates (by property of median of nine).
// Let's be a bit more conservative, and set border to 5.
protect := hi-c < 5
if !protect && hi-c < (hi-lo)/4 {
// Lets test some points for equality to pivot
dups := 0
if data[pivot].literal > data[hi-1].literal { // data[hi-1] = pivot
data[c], data[hi-1] = data[hi-1], data[c]
c++
dups++
}
if data[b-1].literal > data[pivot].literal { // data[b-1] = pivot
b--
dups++
}
// m-lo = (hi-lo)/2 > 6
// b-lo > (hi-lo)*3/4-1 > 8
// ==> m < b ==> data[m] <= pivot
if data[m].literal > data[pivot].literal { // data[m] = pivot
data[m], data[b-1] = data[b-1], data[m]
b--
dups++
}
// if at least 2 points are equal to pivot, assume skewed distribution
protect = dups > 1
}
if protect {
// Protect against a lot of duplicates
// Add invariant:
// data[a <= i < b] unexamined
// data[b <= i < c] = pivot
for {
for ; a < b && data[b-1].literal > data[pivot].literal; b-- { // data[b] == pivot
}
for ; a < b && data[a].literal < data[pivot].literal; a++ { // data[a] < pivot
}
if a >= b {
break
}
// data[a] == pivot; data[b-1] < pivot
data[a], data[b-1] = data[b-1], data[a]
a++
b--
}
}
// Swap pivot into middle
data[pivot], data[b-1] = data[b-1], data[pivot]
return b - 1, c
}
// Insertion sort
func insertionSort(data []literalNode, a, b int) {
for i := a + 1; i < b; i++ {
for j := i; j > a && data[j].literal < data[j-1].literal; j-- {
data[j], data[j-1] = data[j-1], data[j]
}
}
}
// maxDepth returns a threshold at which quicksort should switch
// to heapsort. It returns 2*ceil(lg(n+1)).
func maxDepth(n int) int {
var depth int
for i := n; i > 0; i >>= 1 {
depth++
}
return depth * 2
}
// medianOfThree moves the median of the three values data[m0], data[m1], data[m2] into data[m1].
func medianOfThree(data []literalNode, m1, m0, m2 int) {
// sort 3 elements
if data[m1].literal < data[m0].literal {
data[m1], data[m0] = data[m0], data[m1]
}
// data[m0] <= data[m1]
if data[m2].literal < data[m1].literal {
data[m2], data[m1] = data[m1], data[m2]
// data[m0] <= data[m2] && data[m1] < data[m2]
if data[m1].literal < data[m0].literal {
data[m1], data[m0] = data[m0], data[m1]
}
}
// now data[m0] <= data[m1] <= data[m2]
}

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src/cmd/linuxkit/vendor/github.com/klauspost/compress/flate/inflate.go generated vendored Normal file
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// 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 flate implements the DEFLATE compressed data format, described in
// RFC 1951. The gzip and zlib packages implement access to DEFLATE-based file
// formats.
package flate
import (
"bufio"
"compress/flate"
"fmt"
"io"
"math/bits"
"sync"
)
const (
maxCodeLen = 16 // max length of Huffman code
maxCodeLenMask = 15 // mask for max length of Huffman code
// The next three numbers come from the RFC section 3.2.7, with the
// additional proviso in section 3.2.5 which implies that distance codes
// 30 and 31 should never occur in compressed data.
maxNumLit = 286
maxNumDist = 30
numCodes = 19 // number of codes in Huffman meta-code
debugDecode = false
)
// Value of length - 3 and extra bits.
type lengthExtra struct {
length, extra uint8
}
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
// A CorruptInputError reports the presence of corrupt input at a given offset.
type CorruptInputError = flate.CorruptInputError
// An InternalError reports an error in the flate code itself.
type InternalError string
func (e InternalError) Error() string { return "flate: internal error: " + string(e) }
// A ReadError reports an error encountered while reading input.
//
// Deprecated: No longer returned.
type ReadError = flate.ReadError
// A WriteError reports an error encountered while writing output.
//
// Deprecated: No longer returned.
type WriteError = flate.WriteError
// Resetter resets a ReadCloser returned by NewReader or NewReaderDict to
// to switch to a new underlying Reader. This permits reusing a ReadCloser
// instead of allocating a new one.
type Resetter interface {
// Reset discards any buffered data and resets the Resetter as if it was
// newly initialized with the given reader.
Reset(r io.Reader, dict []byte) error
}
// The data structure for decoding Huffman tables is based on that of
// zlib. There is a lookup table of a fixed bit width (huffmanChunkBits),
// For codes smaller than the table width, there are multiple entries
// (each combination of trailing bits has the same value). For codes
// larger than the table width, the table contains a link to an overflow
// table. The width of each entry in the link table is the maximum code
// size minus the chunk width.
//
// Note that you can do a lookup in the table even without all bits
// filled. Since the extra bits are zero, and the DEFLATE Huffman codes
// have the property that shorter codes come before longer ones, the
// bit length estimate in the result is a lower bound on the actual
// number of bits.
//
// See the following:
// http://www.gzip.org/algorithm.txt
// chunk & 15 is number of bits
// chunk >> 4 is value, including table link
const (
huffmanChunkBits = 9
huffmanNumChunks = 1 << huffmanChunkBits
huffmanCountMask = 15
huffmanValueShift = 4
)
type huffmanDecoder struct {
maxRead int // the maximum number of bits we can read and not overread
chunks *[huffmanNumChunks]uint16 // chunks as described above
links [][]uint16 // overflow links
linkMask uint32 // mask the width of the link table
}
// Initialize Huffman decoding tables from array of code lengths.
// Following this function, h is guaranteed to be initialized into a complete
// tree (i.e., neither over-subscribed nor under-subscribed). The exception is a
// degenerate case where the tree has only a single symbol with length 1. Empty
// trees are permitted.
func (h *huffmanDecoder) init(lengths []int) bool {
// Sanity enables additional runtime tests during Huffman
// table construction. It's intended to be used during
// development to supplement the currently ad-hoc unit tests.
const sanity = false
if h.chunks == nil {
h.chunks = &[huffmanNumChunks]uint16{}
}
if h.maxRead != 0 {
*h = huffmanDecoder{chunks: h.chunks, links: h.links}
}
// Count number of codes of each length,
// compute maxRead and max length.
var count [maxCodeLen]int
var min, max int
for _, n := range lengths {
if n == 0 {
continue
}
if min == 0 || n < min {
min = n
}
if n > max {
max = n
}
count[n&maxCodeLenMask]++
}
// Empty tree. The decompressor.huffSym function will fail later if the tree
// is used. Technically, an empty tree is only valid for the HDIST tree and
// not the HCLEN and HLIT tree. However, a stream with an empty HCLEN tree
// is guaranteed to fail since it will attempt to use the tree to decode the
// codes for the HLIT and HDIST trees. Similarly, an empty HLIT tree is
// guaranteed to fail later since the compressed data section must be
// composed of at least one symbol (the end-of-block marker).
if max == 0 {
return true
}
code := 0
var nextcode [maxCodeLen]int
for i := min; i <= max; i++ {
code <<= 1
nextcode[i&maxCodeLenMask] = code
code += count[i&maxCodeLenMask]
}
// Check that the coding is complete (i.e., that we've
// assigned all 2-to-the-max possible bit sequences).
// Exception: To be compatible with zlib, we also need to
// accept degenerate single-code codings. See also
// TestDegenerateHuffmanCoding.
if code != 1<<uint(max) && !(code == 1 && max == 1) {
if debugDecode {
fmt.Println("coding failed, code, max:", code, max, code == 1<<uint(max), code == 1 && max == 1, "(one should be true)")
}
return false
}
h.maxRead = min
chunks := h.chunks[:]
for i := range chunks {
chunks[i] = 0
}
if max > huffmanChunkBits {
numLinks := 1 << (uint(max) - huffmanChunkBits)
h.linkMask = uint32(numLinks - 1)
// create link tables
link := nextcode[huffmanChunkBits+1] >> 1
if cap(h.links) < huffmanNumChunks-link {
h.links = make([][]uint16, huffmanNumChunks-link)
} else {
h.links = h.links[:huffmanNumChunks-link]
}
for j := uint(link); j < huffmanNumChunks; j++ {
reverse := int(bits.Reverse16(uint16(j)))
reverse >>= uint(16 - huffmanChunkBits)
off := j - uint(link)
if sanity && h.chunks[reverse] != 0 {
panic("impossible: overwriting existing chunk")
}
h.chunks[reverse] = uint16(off<<huffmanValueShift | (huffmanChunkBits + 1))
if cap(h.links[off]) < numLinks {
h.links[off] = make([]uint16, numLinks)
} else {
links := h.links[off][:0]
h.links[off] = links[:numLinks]
}
}
} else {
h.links = h.links[:0]
}
for i, n := range lengths {
if n == 0 {
continue
}
code := nextcode[n]
nextcode[n]++
chunk := uint16(i<<huffmanValueShift | n)
reverse := int(bits.Reverse16(uint16(code)))
reverse >>= uint(16 - n)
if n <= huffmanChunkBits {
for off := reverse; off < len(h.chunks); off += 1 << uint(n) {
// We should never need to overwrite
// an existing chunk. Also, 0 is
// never a valid chunk, because the
// lower 4 "count" bits should be
// between 1 and 15.
if sanity && h.chunks[off] != 0 {
panic("impossible: overwriting existing chunk")
}
h.chunks[off] = chunk
}
} else {
j := reverse & (huffmanNumChunks - 1)
if sanity && h.chunks[j]&huffmanCountMask != huffmanChunkBits+1 {
// Longer codes should have been
// associated with a link table above.
panic("impossible: not an indirect chunk")
}
value := h.chunks[j] >> huffmanValueShift
linktab := h.links[value]
reverse >>= huffmanChunkBits
for off := reverse; off < len(linktab); off += 1 << uint(n-huffmanChunkBits) {
if sanity && linktab[off] != 0 {
panic("impossible: overwriting existing chunk")
}
linktab[off] = chunk
}
}
}
if sanity {
// Above we've sanity checked that we never overwrote
// an existing entry. Here we additionally check that
// we filled the tables completely.
for i, chunk := range h.chunks {
if chunk == 0 {
// As an exception, in the degenerate
// single-code case, we allow odd
// chunks to be missing.
if code == 1 && i%2 == 1 {
continue
}
panic("impossible: missing chunk")
}
}
for _, linktab := range h.links {
for _, chunk := range linktab {
if chunk == 0 {
panic("impossible: missing chunk")
}
}
}
}
return true
}
// The actual read interface needed by NewReader.
// If the passed in io.Reader does not also have ReadByte,
// the NewReader will introduce its own buffering.
type Reader interface {
io.Reader
io.ByteReader
}
// Decompress state.
type decompressor struct {
// Input source.
r Reader
roffset int64
// Huffman decoders for literal/length, distance.
h1, h2 huffmanDecoder
// Length arrays used to define Huffman codes.
bits *[maxNumLit + maxNumDist]int
codebits *[numCodes]int
// Output history, buffer.
dict dictDecoder
// Next step in the decompression,
// and decompression state.
step func(*decompressor)
stepState int
err error
toRead []byte
hl, hd *huffmanDecoder
copyLen int
copyDist int
// Temporary buffer (avoids repeated allocation).
buf [4]byte
// Input bits, in top of b.
b uint32
nb uint
final bool
}
func (f *decompressor) nextBlock() {
for f.nb < 1+2 {
if f.err = f.moreBits(); f.err != nil {
return
}
}
f.final = f.b&1 == 1
f.b >>= 1
typ := f.b & 3
f.b >>= 2
f.nb -= 1 + 2
switch typ {
case 0:
f.dataBlock()
if debugDecode {
fmt.Println("stored block")
}
case 1:
// compressed, fixed Huffman tables
f.hl = &fixedHuffmanDecoder
f.hd = nil
f.huffmanBlockDecoder()()
if debugDecode {
fmt.Println("predefinied huffman block")
}
case 2:
// compressed, dynamic Huffman tables
if f.err = f.readHuffman(); f.err != nil {
break
}
f.hl = &f.h1
f.hd = &f.h2
f.huffmanBlockDecoder()()
if debugDecode {
fmt.Println("dynamic huffman block")
}
default:
// 3 is reserved.
if debugDecode {
fmt.Println("reserved data block encountered")
}
f.err = CorruptInputError(f.roffset)
}
}
func (f *decompressor) Read(b []byte) (int, error) {
for {
if len(f.toRead) > 0 {
n := copy(b, f.toRead)
f.toRead = f.toRead[n:]
if len(f.toRead) == 0 {
return n, f.err
}
return n, nil
}
if f.err != nil {
return 0, f.err
}
f.step(f)
if f.err != nil && len(f.toRead) == 0 {
f.toRead = f.dict.readFlush() // Flush what's left in case of error
}
}
}
// Support the io.WriteTo interface for io.Copy and friends.
func (f *decompressor) WriteTo(w io.Writer) (int64, error) {
total := int64(0)
flushed := false
for {
if len(f.toRead) > 0 {
n, err := w.Write(f.toRead)
total += int64(n)
if err != nil {
f.err = err
return total, err
}
if n != len(f.toRead) {
return total, io.ErrShortWrite
}
f.toRead = f.toRead[:0]
}
if f.err != nil && flushed {
if f.err == io.EOF {
return total, nil
}
return total, f.err
}
if f.err == nil {
f.step(f)
}
if len(f.toRead) == 0 && f.err != nil && !flushed {
f.toRead = f.dict.readFlush() // Flush what's left in case of error
flushed = true
}
}
}
func (f *decompressor) Close() error {
if f.err == io.EOF {
return nil
}
return f.err
}
// RFC 1951 section 3.2.7.
// Compression with dynamic Huffman codes
var codeOrder = [...]int{16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15}
func (f *decompressor) readHuffman() error {
// HLIT[5], HDIST[5], HCLEN[4].
for f.nb < 5+5+4 {
if err := f.moreBits(); err != nil {
return err
}
}
nlit := int(f.b&0x1F) + 257
if nlit > maxNumLit {
if debugDecode {
fmt.Println("nlit > maxNumLit", nlit)
}
return CorruptInputError(f.roffset)
}
f.b >>= 5
ndist := int(f.b&0x1F) + 1
if ndist > maxNumDist {
if debugDecode {
fmt.Println("ndist > maxNumDist", ndist)
}
return CorruptInputError(f.roffset)
}
f.b >>= 5
nclen := int(f.b&0xF) + 4
// numCodes is 19, so nclen is always valid.
f.b >>= 4
f.nb -= 5 + 5 + 4
// (HCLEN+4)*3 bits: code lengths in the magic codeOrder order.
for i := 0; i < nclen; i++ {
for f.nb < 3 {
if err := f.moreBits(); err != nil {
return err
}
}
f.codebits[codeOrder[i]] = int(f.b & 0x7)
f.b >>= 3
f.nb -= 3
}
for i := nclen; i < len(codeOrder); i++ {
f.codebits[codeOrder[i]] = 0
}
if !f.h1.init(f.codebits[0:]) {
if debugDecode {
fmt.Println("init codebits failed")
}
return CorruptInputError(f.roffset)
}
// HLIT + 257 code lengths, HDIST + 1 code lengths,
// using the code length Huffman code.
for i, n := 0, nlit+ndist; i < n; {
x, err := f.huffSym(&f.h1)
if err != nil {
return err
}
if x < 16 {
// Actual length.
f.bits[i] = x
i++
continue
}
// Repeat previous length or zero.
var rep int
var nb uint
var b int
switch x {
default:
return InternalError("unexpected length code")
case 16:
rep = 3
nb = 2
if i == 0 {
if debugDecode {
fmt.Println("i==0")
}
return CorruptInputError(f.roffset)
}
b = f.bits[i-1]
case 17:
rep = 3
nb = 3
b = 0
case 18:
rep = 11
nb = 7
b = 0
}
for f.nb < nb {
if err := f.moreBits(); err != nil {
if debugDecode {
fmt.Println("morebits:", err)
}
return err
}
}
rep += int(f.b & uint32(1<<(nb&regSizeMaskUint32)-1))
f.b >>= nb & regSizeMaskUint32
f.nb -= nb
if i+rep > n {
if debugDecode {
fmt.Println("i+rep > n", i, rep, n)
}
return CorruptInputError(f.roffset)
}
for j := 0; j < rep; j++ {
f.bits[i] = b
i++
}
}
if !f.h1.init(f.bits[0:nlit]) || !f.h2.init(f.bits[nlit:nlit+ndist]) {
if debugDecode {
fmt.Println("init2 failed")
}
return CorruptInputError(f.roffset)
}
// As an optimization, we can initialize the maxRead bits to read at a time
// for the HLIT tree to the length of the EOB marker since we know that
// every block must terminate with one. This preserves the property that
// we never read any extra bytes after the end of the DEFLATE stream.
if f.h1.maxRead < f.bits[endBlockMarker] {
f.h1.maxRead = f.bits[endBlockMarker]
}
if !f.final {
// If not the final block, the smallest block possible is
// a predefined table, BTYPE=01, with a single EOB marker.
// This will take up 3 + 7 bits.
f.h1.maxRead += 10
}
return nil
}
// Copy a single uncompressed data block from input to output.
func (f *decompressor) dataBlock() {
// Uncompressed.
// Discard current half-byte.
left := (f.nb) & 7
f.nb -= left
f.b >>= left
offBytes := f.nb >> 3
// Unfilled values will be overwritten.
f.buf[0] = uint8(f.b)
f.buf[1] = uint8(f.b >> 8)
f.buf[2] = uint8(f.b >> 16)
f.buf[3] = uint8(f.b >> 24)
f.roffset += int64(offBytes)
f.nb, f.b = 0, 0
// Length then ones-complement of length.
nr, err := io.ReadFull(f.r, f.buf[offBytes:4])
f.roffset += int64(nr)
if err != nil {
f.err = noEOF(err)
return
}
n := uint16(f.buf[0]) | uint16(f.buf[1])<<8
nn := uint16(f.buf[2]) | uint16(f.buf[3])<<8
if nn != ^n {
if debugDecode {
ncomp := ^n
fmt.Println("uint16(nn) != uint16(^n)", nn, ncomp)
}
f.err = CorruptInputError(f.roffset)
return
}
if n == 0 {
f.toRead = f.dict.readFlush()
f.finishBlock()
return
}
f.copyLen = int(n)
f.copyData()
}
// copyData copies f.copyLen bytes from the underlying reader into f.hist.
// It pauses for reads when f.hist is full.
func (f *decompressor) copyData() {
buf := f.dict.writeSlice()
if len(buf) > f.copyLen {
buf = buf[:f.copyLen]
}
cnt, err := io.ReadFull(f.r, buf)
f.roffset += int64(cnt)
f.copyLen -= cnt
f.dict.writeMark(cnt)
if err != nil {
f.err = noEOF(err)
return
}
if f.dict.availWrite() == 0 || f.copyLen > 0 {
f.toRead = f.dict.readFlush()
f.step = (*decompressor).copyData
return
}
f.finishBlock()
}
func (f *decompressor) finishBlock() {
if f.final {
if f.dict.availRead() > 0 {
f.toRead = f.dict.readFlush()
}
f.err = io.EOF
}
f.step = (*decompressor).nextBlock
}
// noEOF returns err, unless err == io.EOF, in which case it returns io.ErrUnexpectedEOF.
func noEOF(e error) error {
if e == io.EOF {
return io.ErrUnexpectedEOF
}
return e
}
func (f *decompressor) moreBits() error {
c, err := f.r.ReadByte()
if err != nil {
return noEOF(err)
}
f.roffset++
f.b |= uint32(c) << (f.nb & regSizeMaskUint32)
f.nb += 8
return nil
}
// Read the next Huffman-encoded symbol from f according to h.
func (f *decompressor) huffSym(h *huffmanDecoder) (int, error) {
// 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(h.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
return 0, noEOF(err)
}
f.roffset++
b |= uint32(c) << (nb & regSizeMaskUint32)
nb += 8
}
chunk := h.chunks[b&(huffmanNumChunks-1)]
n = uint(chunk & huffmanCountMask)
if n > huffmanChunkBits {
chunk = h.links[chunk>>huffmanValueShift][(b>>huffmanChunkBits)&h.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 0, f.err
}
f.b = b >> (n & regSizeMaskUint32)
f.nb = nb - n
return int(chunk >> huffmanValueShift), nil
}
}
}
func makeReader(r io.Reader) Reader {
if rr, ok := r.(Reader); ok {
return rr
}
return bufio.NewReader(r)
}
func fixedHuffmanDecoderInit() {
fixedOnce.Do(func() {
// These come from the RFC section 3.2.6.
var bits [288]int
for i := 0; i < 144; i++ {
bits[i] = 8
}
for i := 144; i < 256; i++ {
bits[i] = 9
}
for i := 256; i < 280; i++ {
bits[i] = 7
}
for i := 280; i < 288; i++ {
bits[i] = 8
}
fixedHuffmanDecoder.init(bits[:])
})
}
func (f *decompressor) Reset(r io.Reader, dict []byte) error {
*f = decompressor{
r: makeReader(r),
bits: f.bits,
codebits: f.codebits,
h1: f.h1,
h2: f.h2,
dict: f.dict,
step: (*decompressor).nextBlock,
}
f.dict.init(maxMatchOffset, dict)
return nil
}
// NewReader returns a new ReadCloser that can be used
// to read the uncompressed version of r.
// If r does not also implement io.ByteReader,
// the decompressor may read more data than necessary from r.
// It is the caller's responsibility to call Close on the ReadCloser
// when finished reading.
//
// The ReadCloser returned by NewReader also implements Resetter.
func NewReader(r io.Reader) io.ReadCloser {
fixedHuffmanDecoderInit()
var f decompressor
f.r = makeReader(r)
f.bits = new([maxNumLit + maxNumDist]int)
f.codebits = new([numCodes]int)
f.step = (*decompressor).nextBlock
f.dict.init(maxMatchOffset, nil)
return &f
}
// NewReaderDict is like NewReader but initializes the reader
// with a preset dictionary. The returned Reader behaves as if
// the uncompressed data stream started with the given dictionary,
// which has already been read. NewReaderDict is typically used
// to read data compressed by NewWriterDict.
//
// The ReadCloser returned by NewReader also implements Resetter.
func NewReaderDict(r io.Reader, dict []byte) io.ReadCloser {
fixedHuffmanDecoderInit()
var f decompressor
f.r = makeReader(r)
f.bits = new([maxNumLit + maxNumDist]int)
f.codebits = new([numCodes]int)
f.step = (*decompressor).nextBlock
f.dict.init(maxMatchOffset, dict)
return &f
}

1283
src/cmd/linuxkit/vendor/github.com/klauspost/compress/flate/inflate_gen.go generated vendored Normal file
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File diff suppressed because it is too large Load Diff

240
src/cmd/linuxkit/vendor/github.com/klauspost/compress/flate/level1.go generated vendored Normal file
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@@ -0,0 +1,240 @@
package flate
import (
"encoding/binary"
"fmt"
"math/bits"
)
// fastGen maintains the table for matches,
// and the previous byte block for level 2.
// This is the generic implementation.
type fastEncL1 struct {
fastGen
table [tableSize]tableEntry
}
// EncodeL1 uses a similar algorithm to level 1
func (e *fastEncL1) Encode(dst *tokens, src []byte) {
const (
inputMargin = 12 - 1
minNonLiteralBlockSize = 1 + 1 + inputMargin
)
if debugDeflate && e.cur < 0 {
panic(fmt.Sprint("e.cur < 0: ", e.cur))
}
// Protect against e.cur wraparound.
for e.cur >= bufferReset {
if len(e.hist) == 0 {
for i := range e.table[:] {
e.table[i] = tableEntry{}
}
e.cur = maxMatchOffset
break
}
// Shift down everything in the table that isn't already too far away.
minOff := e.cur + int32(len(e.hist)) - maxMatchOffset
for i := range e.table[:] {
v := e.table[i].offset
if v <= minOff {
v = 0
} else {
v = v - e.cur + maxMatchOffset
}
e.table[i].offset = v
}
e.cur = maxMatchOffset
}
s := e.addBlock(src)
// This check isn't in the Snappy implementation, but there, the caller
// instead of the callee handles this case.
if len(src) < minNonLiteralBlockSize {
// We do not fill the token table.
// This will be picked up by caller.
dst.n = uint16(len(src))
return
}
// Override src
src = e.hist
nextEmit := s
// sLimit is when to stop looking for offset/length copies. The inputMargin
// lets us use a fast path for emitLiteral in the main loop, while we are
// looking for copies.
sLimit := int32(len(src) - inputMargin)
// nextEmit is where in src the next emitLiteral should start from.
cv := load3232(src, s)
for {
const skipLog = 5
const doEvery = 2
nextS := s
var candidate tableEntry
for {
nextHash := hash(cv)
candidate = e.table[nextHash]
nextS = s + doEvery + (s-nextEmit)>>skipLog
if nextS > sLimit {
goto emitRemainder
}
now := load6432(src, nextS)
e.table[nextHash] = tableEntry{offset: s + e.cur}
nextHash = hash(uint32(now))
offset := s - (candidate.offset - e.cur)
if offset < maxMatchOffset && cv == load3232(src, candidate.offset-e.cur) {
e.table[nextHash] = tableEntry{offset: nextS + e.cur}
break
}
// Do one right away...
cv = uint32(now)
s = nextS
nextS++
candidate = e.table[nextHash]
now >>= 8
e.table[nextHash] = tableEntry{offset: s + e.cur}
offset = s - (candidate.offset - e.cur)
if offset < maxMatchOffset && cv == load3232(src, candidate.offset-e.cur) {
e.table[nextHash] = tableEntry{offset: nextS + e.cur}
break
}
cv = uint32(now)
s = nextS
}
// A 4-byte match has been found. We'll later see if more than 4 bytes
// match. But, prior to the match, src[nextEmit:s] are unmatched. Emit
// them as literal bytes.
for {
// Invariant: we have a 4-byte match at s, and no need to emit any
// literal bytes prior to s.
// Extend the 4-byte match as long as possible.
t := candidate.offset - e.cur
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] {
s--
t--
l++
}
if nextEmit < s {
if false {
emitLiteral(dst, src[nextEmit:s])
} else {
for _, v := range src[nextEmit:s] {
dst.tokens[dst.n] = token(v)
dst.litHist[v]++
dst.n++
}
}
}
// Save the match found
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 {
if xl > 258+baseMatchLength {
xl = 258
} else {
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 {
s = nextS + 1
}
if s >= sLimit {
// Index first pair after match end.
if int(s+l+4) < len(src) {
cv := load3232(src, s)
e.table[hash(cv)] = tableEntry{offset: s + e.cur}
}
goto emitRemainder
}
// We could immediately start working at s now, but to improve
// compression we first update the hash table at s-2 and at s. If
// another emitCopy is not our next move, also calculate nextHash
// at s+1. At least on GOARCH=amd64, these three hash calculations
// are faster as one load64 call (with some shifts) instead of
// three load32 calls.
x := load6432(src, s-2)
o := e.cur + s - 2
prevHash := hash(uint32(x))
e.table[prevHash] = tableEntry{offset: o}
x >>= 16
currHash := hash(uint32(x))
candidate = e.table[currHash]
e.table[currHash] = tableEntry{offset: o + 2}
offset := s - (candidate.offset - e.cur)
if offset > maxMatchOffset || uint32(x) != load3232(src, candidate.offset-e.cur) {
cv = uint32(x >> 8)
s++
break
}
}
}
emitRemainder:
if int(nextEmit) < len(src) {
// If nothing was added, don't encode literals.
if dst.n == 0 {
return
}
emitLiteral(dst, src[nextEmit:])
}
}

213
src/cmd/linuxkit/vendor/github.com/klauspost/compress/flate/level2.go generated vendored Normal file
View File

@@ -0,0 +1,213 @@
package flate
import "fmt"
// fastGen maintains the table for matches,
// and the previous byte block for level 2.
// This is the generic implementation.
type fastEncL2 struct {
fastGen
table [bTableSize]tableEntry
}
// EncodeL2 uses a similar algorithm to level 1, but is capable
// of matching across blocks giving better compression at a small slowdown.
func (e *fastEncL2) Encode(dst *tokens, src []byte) {
const (
inputMargin = 12 - 1
minNonLiteralBlockSize = 1 + 1 + inputMargin
)
if debugDeflate && e.cur < 0 {
panic(fmt.Sprint("e.cur < 0: ", e.cur))
}
// Protect against e.cur wraparound.
for e.cur >= bufferReset {
if len(e.hist) == 0 {
for i := range e.table[:] {
e.table[i] = tableEntry{}
}
e.cur = maxMatchOffset
break
}
// Shift down everything in the table that isn't already too far away.
minOff := e.cur + int32(len(e.hist)) - maxMatchOffset
for i := range e.table[:] {
v := e.table[i].offset
if v <= minOff {
v = 0
} else {
v = v - e.cur + maxMatchOffset
}
e.table[i].offset = v
}
e.cur = maxMatchOffset
}
s := e.addBlock(src)
// This check isn't in the Snappy implementation, but there, the caller
// instead of the callee handles this case.
if len(src) < minNonLiteralBlockSize {
// We do not fill the token table.
// This will be picked up by caller.
dst.n = uint16(len(src))
return
}
// Override src
src = e.hist
nextEmit := s
// sLimit is when to stop looking for offset/length copies. The inputMargin
// lets us use a fast path for emitLiteral in the main loop, while we are
// looking for copies.
sLimit := int32(len(src) - inputMargin)
// nextEmit is where in src the next emitLiteral should start from.
cv := load3232(src, s)
for {
// When should we start skipping if we haven't found matches in a long while.
const skipLog = 5
const doEvery = 2
nextS := s
var candidate tableEntry
for {
nextHash := hash4u(cv, bTableBits)
s = nextS
nextS = s + doEvery + (s-nextEmit)>>skipLog
if nextS > sLimit {
goto emitRemainder
}
candidate = e.table[nextHash]
now := load6432(src, nextS)
e.table[nextHash] = tableEntry{offset: s + e.cur}
nextHash = hash4u(uint32(now), bTableBits)
offset := s - (candidate.offset - e.cur)
if offset < maxMatchOffset && cv == load3232(src, candidate.offset-e.cur) {
e.table[nextHash] = tableEntry{offset: nextS + e.cur}
break
}
// Do one right away...
cv = uint32(now)
s = nextS
nextS++
candidate = e.table[nextHash]
now >>= 8
e.table[nextHash] = tableEntry{offset: s + e.cur}
offset = s - (candidate.offset - e.cur)
if offset < maxMatchOffset && cv == load3232(src, candidate.offset-e.cur) {
break
}
cv = uint32(now)
}
// A 4-byte match has been found. We'll later see if more than 4 bytes
// match. But, prior to the match, src[nextEmit:s] are unmatched. Emit
// them as literal bytes.
// Call emitCopy, and then see if another emitCopy could be our next
// move. Repeat until we find no match for the input immediately after
// what was consumed by the last emitCopy call.
//
// If we exit this loop normally then we need to call emitLiteral next,
// though we don't yet know how big the literal will be. We handle that
// by proceeding to the next iteration of the main loop. We also can
// exit this loop via goto if we get close to exhausting the input.
for {
// Invariant: we have a 4-byte match at s, and no need to emit any
// literal bytes prior to s.
// Extend the 4-byte match as long as possible.
t := candidate.offset - e.cur
l := e.matchlenLong(s+4, t+4, src) + 4
// Extend backwards
for t > 0 && s > nextEmit && src[t-1] == src[s-1] {
s--
t--
l++
}
if nextEmit < s {
if false {
emitLiteral(dst, src[nextEmit:s])
} else {
for _, v := range src[nextEmit:s] {
dst.tokens[dst.n] = token(v)
dst.litHist[v]++
dst.n++
}
}
}
dst.AddMatchLong(l, uint32(s-t-baseMatchOffset))
s += l
nextEmit = s
if nextS >= s {
s = nextS + 1
}
if s >= sLimit {
// Index first pair after match end.
if int(s+l+4) < len(src) {
cv := load3232(src, s)
e.table[hash4u(cv, bTableBits)] = tableEntry{offset: s + e.cur}
}
goto emitRemainder
}
// Store every second hash in-between, but offset by 1.
for i := s - l + 2; i < s-5; i += 7 {
x := load6432(src, i)
nextHash := hash4u(uint32(x), bTableBits)
e.table[nextHash] = tableEntry{offset: e.cur + i}
// Skip one
x >>= 16
nextHash = hash4u(uint32(x), bTableBits)
e.table[nextHash] = tableEntry{offset: e.cur + i + 2}
// Skip one
x >>= 16
nextHash = hash4u(uint32(x), bTableBits)
e.table[nextHash] = tableEntry{offset: e.cur + i + 4}
}
// We could immediately start working at s now, but to improve
// compression we first update the hash table at s-2 to s. If
// another emitCopy is not our next move, also calculate nextHash
// at s+1. At least on GOARCH=amd64, these three hash calculations
// are faster as one load64 call (with some shifts) instead of
// three load32 calls.
x := load6432(src, s-2)
o := e.cur + s - 2
prevHash := hash4u(uint32(x), bTableBits)
prevHash2 := hash4u(uint32(x>>8), bTableBits)
e.table[prevHash] = tableEntry{offset: o}
e.table[prevHash2] = tableEntry{offset: o + 1}
currHash := hash4u(uint32(x>>16), bTableBits)
candidate = e.table[currHash]
e.table[currHash] = tableEntry{offset: o + 2}
offset := s - (candidate.offset - e.cur)
if offset > maxMatchOffset || uint32(x>>16) != load3232(src, candidate.offset-e.cur) {
cv = uint32(x >> 24)
s++
break
}
}
}
emitRemainder:
if int(nextEmit) < len(src) {
// If nothing was added, don't encode literals.
if dst.n == 0 {
return
}
emitLiteral(dst, src[nextEmit:])
}
}

240
src/cmd/linuxkit/vendor/github.com/klauspost/compress/flate/level3.go generated vendored Normal file
View File

@@ -0,0 +1,240 @@
package flate
import "fmt"
// fastEncL3
type fastEncL3 struct {
fastGen
table [1 << 16]tableEntryPrev
}
// Encode uses a similar algorithm to level 2, will check up to two candidates.
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 {
panic(fmt.Sprint("e.cur < 0: ", e.cur))
}
// Protect against e.cur wraparound.
for e.cur >= bufferReset {
if len(e.hist) == 0 {
for i := range e.table[:] {
e.table[i] = tableEntryPrev{}
}
e.cur = maxMatchOffset
break
}
// Shift down everything in the table that isn't already too far away.
minOff := e.cur + int32(len(e.hist)) - maxMatchOffset
for i := range e.table[:] {
v := e.table[i]
if v.Cur.offset <= minOff {
v.Cur.offset = 0
} else {
v.Cur.offset = v.Cur.offset - e.cur + maxMatchOffset
}
if v.Prev.offset <= minOff {
v.Prev.offset = 0
} else {
v.Prev.offset = v.Prev.offset - e.cur + maxMatchOffset
}
e.table[i] = v
}
e.cur = maxMatchOffset
}
s := e.addBlock(src)
// Skip if too small.
if len(src) < minNonLiteralBlockSize {
// We do not fill the token table.
// This will be picked up by caller.
dst.n = uint16(len(src))
return
}
// Override src
src = e.hist
nextEmit := s
// sLimit is when to stop looking for offset/length copies. The inputMargin
// lets us use a fast path for emitLiteral in the main loop, while we are
// looking for copies.
sLimit := int32(len(src) - inputMargin)
// nextEmit is where in src the next emitLiteral should start from.
cv := load3232(src, s)
for {
const skipLog = 6
nextS := s
var candidate tableEntry
for {
nextHash := hash4u(cv, tableBits)
s = nextS
nextS = s + 1 + (s-nextEmit)>>skipLog
if nextS > sLimit {
goto emitRemainder
}
candidates := e.table[nextHash]
now := load3232(src, nextS)
// Safe offset distance until s + 4...
minOffset := e.cur + s - (maxMatchOffset - 4)
e.table[nextHash] = tableEntryPrev{Prev: candidates.Cur, Cur: tableEntry{offset: s + e.cur}}
// Check both candidates
candidate = candidates.Cur
if candidate.offset < minOffset {
cv = now
// Previous will also be invalid, we have nothing.
continue
}
if cv == load3232(src, candidate.offset-e.cur) {
if candidates.Prev.offset < minOffset || cv != load3232(src, candidates.Prev.offset-e.cur) {
break
}
// Both match and are valid, pick longest.
offset := s - (candidate.offset - e.cur)
o2 := s - (candidates.Prev.offset - e.cur)
l1, l2 := matchLen(src[s+4:], src[s-offset+4:]), matchLen(src[s+4:], src[s-o2+4:])
if l2 > l1 {
candidate = candidates.Prev
}
break
} else {
// We only check if value mismatches.
// Offset will always be invalid in other cases.
candidate = candidates.Prev
if candidate.offset > minOffset && cv == load3232(src, candidate.offset-e.cur) {
break
}
}
cv = now
}
// Call emitCopy, and then see if another emitCopy could be our next
// move. Repeat until we find no match for the input immediately after
// what was consumed by the last emitCopy call.
//
// If we exit this loop normally then we need to call emitLiteral next,
// though we don't yet know how big the literal will be. We handle that
// by proceeding to the next iteration of the main loop. We also can
// exit this loop via goto if we get close to exhausting the input.
for {
// Invariant: we have a 4-byte match at s, and no need to emit any
// literal bytes prior to s.
// Extend the 4-byte match as long as possible.
//
t := candidate.offset - e.cur
l := e.matchlenLong(s+4, t+4, src) + 4
// Extend backwards
for t > 0 && s > nextEmit && src[t-1] == src[s-1] {
s--
t--
l++
}
if nextEmit < s {
if false {
emitLiteral(dst, src[nextEmit:s])
} else {
for _, v := range src[nextEmit:s] {
dst.tokens[dst.n] = token(v)
dst.litHist[v]++
dst.n++
}
}
}
dst.AddMatchLong(l, uint32(s-t-baseMatchOffset))
s += l
nextEmit = s
if nextS >= s {
s = nextS + 1
}
if s >= sLimit {
t += l
// Index first pair after match end.
if int(t+4) < len(src) && t > 0 {
cv := load3232(src, t)
nextHash := hash4u(cv, tableBits)
e.table[nextHash] = tableEntryPrev{
Prev: e.table[nextHash].Cur,
Cur: tableEntry{offset: e.cur + t},
}
}
goto emitRemainder
}
// 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}}
}
// 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 = hash4u(uint32(x), tableBits)
e.table[prevHash] = tableEntryPrev{
Prev: e.table[prevHash].Cur,
Cur: tableEntry{offset: e.cur + s - 1},
}
x >>= 8
currHash := hash4u(uint32(x), tableBits)
candidates := e.table[currHash]
cv = uint32(x)
e.table[currHash] = tableEntryPrev{
Prev: candidates.Cur,
Cur: tableEntry{offset: s + e.cur},
}
// Check both candidates
candidate = candidates.Cur
minOffset := e.cur + s - (maxMatchOffset - 4)
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) {
// Match at prev...
continue
}
}
cv = uint32(x >> 8)
s++
break
}
}
emitRemainder:
if int(nextEmit) < len(src) {
// If nothing was added, don't encode literals.
if dst.n == 0 {
return
}
emitLiteral(dst, src[nextEmit:])
}
}

220
src/cmd/linuxkit/vendor/github.com/klauspost/compress/flate/level4.go generated vendored Normal file
View File

@@ -0,0 +1,220 @@
package flate
import "fmt"
type fastEncL4 struct {
fastGen
table [tableSize]tableEntry
bTable [tableSize]tableEntry
}
func (e *fastEncL4) Encode(dst *tokens, src []byte) {
const (
inputMargin = 12 - 1
minNonLiteralBlockSize = 1 + 1 + inputMargin
)
if debugDeflate && e.cur < 0 {
panic(fmt.Sprint("e.cur < 0: ", e.cur))
}
// 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.bTable[:] {
e.bTable[i] = tableEntry{}
}
e.cur = maxMatchOffset
break
}
// Shift down everything in the table that isn't already too far away.
minOff := e.cur + int32(len(e.hist)) - maxMatchOffset
for i := range e.table[:] {
v := e.table[i].offset
if v <= minOff {
v = 0
} else {
v = v - e.cur + maxMatchOffset
}
e.table[i].offset = v
}
for i := range e.bTable[:] {
v := e.bTable[i].offset
if v <= minOff {
v = 0
} else {
v = v - e.cur + maxMatchOffset
}
e.bTable[i].offset = v
}
e.cur = maxMatchOffset
}
s := e.addBlock(src)
// This check isn't in the Snappy implementation, but there, the caller
// instead of the callee handles this case.
if len(src) < minNonLiteralBlockSize {
// We do not fill the token table.
// This will be picked up by caller.
dst.n = uint16(len(src))
return
}
// Override src
src = e.hist
nextEmit := s
// sLimit is when to stop looking for offset/length copies. The inputMargin
// lets us use a fast path for emitLiteral in the main loop, while we are
// looking for copies.
sLimit := int32(len(src) - inputMargin)
// nextEmit is where in src the next emitLiteral should start from.
cv := load6432(src, s)
for {
const skipLog = 6
const doEvery = 1
nextS := s
var t int32
for {
nextHashS := hash4x64(cv, tableBits)
nextHashL := hash7(cv, tableBits)
s = nextS
nextS = s + doEvery + (s-nextEmit)>>skipLog
if nextS > sLimit {
goto emitRemainder
}
// Fetch a short+long candidate
sCandidate := e.table[nextHashS]
lCandidate := e.bTable[nextHashL]
next := load6432(src, nextS)
entry := tableEntry{offset: s + e.cur}
e.table[nextHashS] = entry
e.bTable[nextHashL] = entry
t = lCandidate.offset - e.cur
if s-t < maxMatchOffset && uint32(cv) == load3232(src, lCandidate.offset-e.cur) {
// We got a long match. Use that.
break
}
t = sCandidate.offset - e.cur
if s-t < maxMatchOffset && uint32(cv) == load3232(src, sCandidate.offset-e.cur) {
// Found a 4 match...
lCandidate = e.bTable[hash7(next, tableBits)]
// If the next long is a candidate, check if we should use that instead...
lOff := nextS - (lCandidate.offset - e.cur)
if lOff < maxMatchOffset && load3232(src, lCandidate.offset-e.cur) == uint32(next) {
l1, l2 := matchLen(src[s+4:], src[t+4:]), matchLen(src[nextS+4:], src[nextS-lOff+4:])
if l2 > l1 {
s = nextS
t = lCandidate.offset - e.cur
}
}
break
}
cv = next
}
// A 4-byte match has been found. We'll later see if more than 4 bytes
// match. But, prior to the match, src[nextEmit:s] are unmatched. Emit
// them as literal bytes.
// Extend the 4-byte match as long as possible.
l := e.matchlenLong(s+4, t+4, src) + 4
// Extend backwards
for t > 0 && s > nextEmit && src[t-1] == src[s-1] {
s--
t--
l++
}
if nextEmit < s {
if false {
emitLiteral(dst, src[nextEmit:s])
} else {
for _, v := range src[nextEmit:s] {
dst.tokens[dst.n] = token(v)
dst.litHist[v]++
dst.n++
}
}
}
if debugDeflate {
if t >= s {
panic("s-t")
}
if (s - t) > maxMatchOffset {
panic(fmt.Sprintln("mmo", t))
}
if l < baseMatchLength {
panic("bml")
}
}
dst.AddMatchLong(l, uint32(s-t-baseMatchOffset))
s += l
nextEmit = s
if nextS >= s {
s = nextS + 1
}
if s >= sLimit {
// Index first pair after match end.
if int(s+8) < len(src) {
cv := load6432(src, s)
e.table[hash4x64(cv, tableBits)] = tableEntry{offset: s + e.cur}
e.bTable[hash7(cv, tableBits)] = tableEntry{offset: s + e.cur}
}
goto emitRemainder
}
// Store every 3rd hash in-between
if true {
i := nextS
if i < s-1 {
cv := load6432(src, i)
t := tableEntry{offset: i + e.cur}
t2 := tableEntry{offset: t.offset + 1}
e.bTable[hash7(cv, tableBits)] = t
e.bTable[hash7(cv>>8, tableBits)] = t2
e.table[hash4u(uint32(cv>>8), tableBits)] = t2
i += 3
for ; i < s-1; i += 3 {
cv := load6432(src, i)
t := tableEntry{offset: i + e.cur}
t2 := tableEntry{offset: t.offset + 1}
e.bTable[hash7(cv, tableBits)] = t
e.bTable[hash7(cv>>8, tableBits)] = t2
e.table[hash4u(uint32(cv>>8), tableBits)] = t2
}
}
}
// We could immediately start working at s now, but to improve
// compression we first update the hash table at s-1 and at s.
x := load6432(src, s-1)
o := e.cur + s - 1
prevHashS := hash4x64(x, tableBits)
prevHashL := hash7(x, tableBits)
e.table[prevHashS] = tableEntry{offset: o}
e.bTable[prevHashL] = tableEntry{offset: o}
cv = x >> 8
}
emitRemainder:
if int(nextEmit) < len(src) {
// If nothing was added, don't encode literals.
if dst.n == 0 {
return
}
emitLiteral(dst, src[nextEmit:])
}
}

302
src/cmd/linuxkit/vendor/github.com/klauspost/compress/flate/level5.go generated vendored Normal file
View File

@@ -0,0 +1,302 @@
package flate
import "fmt"
type fastEncL5 struct {
fastGen
table [tableSize]tableEntry
bTable [tableSize]tableEntryPrev
}
func (e *fastEncL5) Encode(dst *tokens, src []byte) {
const (
inputMargin = 12 - 1
minNonLiteralBlockSize = 1 + 1 + inputMargin
)
if debugDeflate && e.cur < 0 {
panic(fmt.Sprint("e.cur < 0: ", e.cur))
}
// 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.bTable[:] {
e.bTable[i] = tableEntryPrev{}
}
e.cur = maxMatchOffset
break
}
// Shift down everything in the table that isn't already too far away.
minOff := e.cur + int32(len(e.hist)) - maxMatchOffset
for i := range e.table[:] {
v := e.table[i].offset
if v <= minOff {
v = 0
} else {
v = v - e.cur + maxMatchOffset
}
e.table[i].offset = v
}
for i := range e.bTable[:] {
v := e.bTable[i]
if v.Cur.offset <= minOff {
v.Cur.offset = 0
v.Prev.offset = 0
} else {
v.Cur.offset = v.Cur.offset - e.cur + maxMatchOffset
if v.Prev.offset <= minOff {
v.Prev.offset = 0
} else {
v.Prev.offset = v.Prev.offset - e.cur + maxMatchOffset
}
}
e.bTable[i] = v
}
e.cur = maxMatchOffset
}
s := e.addBlock(src)
// This check isn't in the Snappy implementation, but there, the caller
// instead of the callee handles this case.
if len(src) < minNonLiteralBlockSize {
// We do not fill the token table.
// This will be picked up by caller.
dst.n = uint16(len(src))
return
}
// Override src
src = e.hist
nextEmit := s
// sLimit is when to stop looking for offset/length copies. The inputMargin
// lets us use a fast path for emitLiteral in the main loop, while we are
// looking for copies.
sLimit := int32(len(src) - inputMargin)
// nextEmit is where in src the next emitLiteral should start from.
cv := load6432(src, s)
for {
const skipLog = 6
const doEvery = 1
nextS := s
var l int32
var t int32
for {
nextHashS := hash4x64(cv, tableBits)
nextHashL := hash7(cv, tableBits)
s = nextS
nextS = s + doEvery + (s-nextEmit)>>skipLog
if nextS > sLimit {
goto emitRemainder
}
// Fetch a short+long candidate
sCandidate := e.table[nextHashS]
lCandidate := e.bTable[nextHashL]
next := load6432(src, nextS)
entry := tableEntry{offset: s + e.cur}
e.table[nextHashS] = entry
eLong := &e.bTable[nextHashL]
eLong.Cur, eLong.Prev = entry, eLong.Cur
nextHashS = hash4x64(next, tableBits)
nextHashL = hash7(next, tableBits)
t = lCandidate.Cur.offset - e.cur
if s-t < maxMatchOffset {
if uint32(cv) == load3232(src, lCandidate.Cur.offset-e.cur) {
// Store the next match
e.table[nextHashS] = tableEntry{offset: nextS + e.cur}
eLong := &e.bTable[nextHashL]
eLong.Cur, eLong.Prev = tableEntry{offset: nextS + e.cur}, eLong.Cur
t2 := lCandidate.Prev.offset - e.cur
if s-t2 < maxMatchOffset && uint32(cv) == load3232(src, lCandidate.Prev.offset-e.cur) {
l = e.matchlen(s+4, t+4, src) + 4
ml1 := e.matchlen(s+4, t2+4, src) + 4
if ml1 > l {
t = t2
l = ml1
break
}
}
break
}
t = lCandidate.Prev.offset - e.cur
if s-t < maxMatchOffset && uint32(cv) == load3232(src, lCandidate.Prev.offset-e.cur) {
// Store the next match
e.table[nextHashS] = tableEntry{offset: nextS + e.cur}
eLong := &e.bTable[nextHashL]
eLong.Cur, eLong.Prev = tableEntry{offset: nextS + e.cur}, eLong.Cur
break
}
}
t = sCandidate.offset - e.cur
if s-t < maxMatchOffset && uint32(cv) == load3232(src, sCandidate.offset-e.cur) {
// Found a 4 match...
l = e.matchlen(s+4, t+4, src) + 4
lCandidate = e.bTable[nextHashL]
// Store the next match
e.table[nextHashS] = tableEntry{offset: nextS + e.cur}
eLong := &e.bTable[nextHashL]
eLong.Cur, eLong.Prev = tableEntry{offset: nextS + e.cur}, eLong.Cur
// If the next long is a candidate, use that...
t2 := lCandidate.Cur.offset - e.cur
if nextS-t2 < maxMatchOffset {
if load3232(src, lCandidate.Cur.offset-e.cur) == uint32(next) {
ml := e.matchlen(nextS+4, t2+4, src) + 4
if ml > l {
t = t2
s = nextS
l = ml
break
}
}
// If the previous long is a candidate, use that...
t2 = lCandidate.Prev.offset - e.cur
if nextS-t2 < maxMatchOffset && load3232(src, lCandidate.Prev.offset-e.cur) == uint32(next) {
ml := e.matchlen(nextS+4, t2+4, src) + 4
if ml > l {
t = t2
s = nextS
l = ml
break
}
}
}
break
}
cv = next
}
// A 4-byte match has been found. We'll later see if more than 4 bytes
// match. But, prior to the match, src[nextEmit:s] are unmatched. Emit
// them as literal bytes.
if l == 0 {
// Extend the 4-byte match as long as possible.
l = e.matchlenLong(s+4, t+4, src) + 4
} else if l == maxMatchLength {
l += e.matchlenLong(s+l, t+l, src)
}
// Try to locate a better match by checking the end of best match...
if sAt := s + l; l < 30 && sAt < sLimit {
eLong := e.bTable[hash7(load6432(src, sAt), tableBits)].Cur.offset
// Test current
t2 := eLong - e.cur - l
off := s - t2
if t2 >= 0 && off < maxMatchOffset && off > 0 {
if l2 := e.matchlenLong(s, t2, src); l2 > l {
t = t2
l = l2
}
}
}
// Extend backwards
for t > 0 && s > nextEmit && src[t-1] == src[s-1] {
s--
t--
l++
}
if nextEmit < s {
if false {
emitLiteral(dst, src[nextEmit:s])
} else {
for _, v := range src[nextEmit:s] {
dst.tokens[dst.n] = token(v)
dst.litHist[v]++
dst.n++
}
}
}
if debugDeflate {
if t >= s {
panic(fmt.Sprintln("s-t", s, t))
}
if (s - t) > maxMatchOffset {
panic(fmt.Sprintln("mmo", s-t))
}
if l < baseMatchLength {
panic("bml")
}
}
dst.AddMatchLong(l, uint32(s-t-baseMatchOffset))
s += l
nextEmit = s
if nextS >= s {
s = nextS + 1
}
if s >= sLimit {
goto emitRemainder
}
// Store every 3rd hash in-between.
if true {
const hashEvery = 3
i := s - l + 1
if i < s-1 {
cv := load6432(src, i)
t := tableEntry{offset: i + e.cur}
e.table[hash4x64(cv, tableBits)] = t
eLong := &e.bTable[hash7(cv, tableBits)]
eLong.Cur, eLong.Prev = t, eLong.Cur
// Do an long at i+1
cv >>= 8
t = tableEntry{offset: t.offset + 1}
eLong = &e.bTable[hash7(cv, tableBits)]
eLong.Cur, eLong.Prev = t, eLong.Cur
// We only have enough bits for a short entry at i+2
cv >>= 8
t = tableEntry{offset: t.offset + 1}
e.table[hash4x64(cv, tableBits)] = t
// Skip one - otherwise we risk hitting 's'
i += 4
for ; i < s-1; i += hashEvery {
cv := load6432(src, i)
t := tableEntry{offset: i + e.cur}
t2 := tableEntry{offset: t.offset + 1}
eLong := &e.bTable[hash7(cv, tableBits)]
eLong.Cur, eLong.Prev = t, eLong.Cur
e.table[hash4u(uint32(cv>>8), tableBits)] = t2
}
}
}
// We could immediately start working at s now, but to improve
// compression we first update the hash table at s-1 and at s.
x := load6432(src, s-1)
o := e.cur + s - 1
prevHashS := hash4x64(x, tableBits)
prevHashL := hash7(x, tableBits)
e.table[prevHashS] = tableEntry{offset: o}
eLong := &e.bTable[prevHashL]
eLong.Cur, eLong.Prev = tableEntry{offset: o}, eLong.Cur
cv = x >> 8
}
emitRemainder:
if int(nextEmit) < len(src) {
// If nothing was added, don't encode literals.
if dst.n == 0 {
return
}
emitLiteral(dst, src[nextEmit:])
}
}

315
src/cmd/linuxkit/vendor/github.com/klauspost/compress/flate/level6.go generated vendored Normal file
View File

@@ -0,0 +1,315 @@
package flate
import "fmt"
type fastEncL6 struct {
fastGen
table [tableSize]tableEntry
bTable [tableSize]tableEntryPrev
}
func (e *fastEncL6) Encode(dst *tokens, src []byte) {
const (
inputMargin = 12 - 1
minNonLiteralBlockSize = 1 + 1 + inputMargin
)
if debugDeflate && e.cur < 0 {
panic(fmt.Sprint("e.cur < 0: ", e.cur))
}
// 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.bTable[:] {
e.bTable[i] = tableEntryPrev{}
}
e.cur = maxMatchOffset
break
}
// Shift down everything in the table that isn't already too far away.
minOff := e.cur + int32(len(e.hist)) - maxMatchOffset
for i := range e.table[:] {
v := e.table[i].offset
if v <= minOff {
v = 0
} else {
v = v - e.cur + maxMatchOffset
}
e.table[i].offset = v
}
for i := range e.bTable[:] {
v := e.bTable[i]
if v.Cur.offset <= minOff {
v.Cur.offset = 0
v.Prev.offset = 0
} else {
v.Cur.offset = v.Cur.offset - e.cur + maxMatchOffset
if v.Prev.offset <= minOff {
v.Prev.offset = 0
} else {
v.Prev.offset = v.Prev.offset - e.cur + maxMatchOffset
}
}
e.bTable[i] = v
}
e.cur = maxMatchOffset
}
s := e.addBlock(src)
// This check isn't in the Snappy implementation, but there, the caller
// instead of the callee handles this case.
if len(src) < minNonLiteralBlockSize {
// We do not fill the token table.
// This will be picked up by caller.
dst.n = uint16(len(src))
return
}
// Override src
src = e.hist
nextEmit := s
// sLimit is when to stop looking for offset/length copies. The inputMargin
// lets us use a fast path for emitLiteral in the main loop, while we are
// looking for copies.
sLimit := int32(len(src) - inputMargin)
// nextEmit is where in src the next emitLiteral should start from.
cv := load6432(src, s)
// Repeat MUST be > 1 and within range
repeat := int32(1)
for {
const skipLog = 7
const doEvery = 1
nextS := s
var l int32
var t int32
for {
nextHashS := hash4x64(cv, tableBits)
nextHashL := hash7(cv, tableBits)
s = nextS
nextS = s + doEvery + (s-nextEmit)>>skipLog
if nextS > sLimit {
goto emitRemainder
}
// Fetch a short+long candidate
sCandidate := e.table[nextHashS]
lCandidate := e.bTable[nextHashL]
next := load6432(src, nextS)
entry := tableEntry{offset: s + e.cur}
e.table[nextHashS] = entry
eLong := &e.bTable[nextHashL]
eLong.Cur, eLong.Prev = entry, eLong.Cur
// Calculate hashes of 'next'
nextHashS = hash4x64(next, tableBits)
nextHashL = hash7(next, tableBits)
t = lCandidate.Cur.offset - e.cur
if s-t < maxMatchOffset {
if uint32(cv) == load3232(src, lCandidate.Cur.offset-e.cur) {
// Long candidate matches at least 4 bytes.
// Store the next match
e.table[nextHashS] = tableEntry{offset: nextS + e.cur}
eLong := &e.bTable[nextHashL]
eLong.Cur, eLong.Prev = tableEntry{offset: nextS + e.cur}, eLong.Cur
// Check the previous long candidate as well.
t2 := lCandidate.Prev.offset - e.cur
if s-t2 < maxMatchOffset && uint32(cv) == load3232(src, lCandidate.Prev.offset-e.cur) {
l = e.matchlen(s+4, t+4, src) + 4
ml1 := e.matchlen(s+4, t2+4, src) + 4
if ml1 > l {
t = t2
l = ml1
break
}
}
break
}
// Current value did not match, but check if previous long value does.
t = lCandidate.Prev.offset - e.cur
if s-t < maxMatchOffset && uint32(cv) == load3232(src, lCandidate.Prev.offset-e.cur) {
// Store the next match
e.table[nextHashS] = tableEntry{offset: nextS + e.cur}
eLong := &e.bTable[nextHashL]
eLong.Cur, eLong.Prev = tableEntry{offset: nextS + e.cur}, eLong.Cur
break
}
}
t = sCandidate.offset - e.cur
if s-t < maxMatchOffset && uint32(cv) == load3232(src, sCandidate.offset-e.cur) {
// Found a 4 match...
l = e.matchlen(s+4, t+4, src) + 4
// Look up next long candidate (at nextS)
lCandidate = e.bTable[nextHashL]
// Store the next match
e.table[nextHashS] = tableEntry{offset: nextS + e.cur}
eLong := &e.bTable[nextHashL]
eLong.Cur, eLong.Prev = tableEntry{offset: nextS + e.cur}, eLong.Cur
// Check repeat at s + repOff
const repOff = 1
t2 := s - repeat + repOff
if load3232(src, t2) == uint32(cv>>(8*repOff)) {
ml := e.matchlen(s+4+repOff, t2+4, src) + 4
if ml > l {
t = t2
l = ml
s += repOff
// Not worth checking more.
break
}
}
// If the next long is a candidate, use that...
t2 = lCandidate.Cur.offset - e.cur
if nextS-t2 < maxMatchOffset {
if load3232(src, lCandidate.Cur.offset-e.cur) == uint32(next) {
ml := e.matchlen(nextS+4, t2+4, src) + 4
if ml > l {
t = t2
s = nextS
l = ml
// This is ok, but check previous as well.
}
}
// If the previous long is a candidate, use that...
t2 = lCandidate.Prev.offset - e.cur
if nextS-t2 < maxMatchOffset && load3232(src, lCandidate.Prev.offset-e.cur) == uint32(next) {
ml := e.matchlen(nextS+4, t2+4, src) + 4
if ml > l {
t = t2
s = nextS
l = ml
break
}
}
}
break
}
cv = next
}
// A 4-byte match has been found. We'll later see if more than 4 bytes
// match. But, prior to the match, src[nextEmit:s] are unmatched. Emit
// them as literal bytes.
// Extend the 4-byte match as long as possible.
if l == 0 {
l = e.matchlenLong(s+4, t+4, src) + 4
} else if l == maxMatchLength {
l += e.matchlenLong(s+l, t+l, src)
}
// Try to locate a better match by checking the end-of-match...
if sAt := s + l; sAt < sLimit {
eLong := &e.bTable[hash7(load6432(src, sAt), tableBits)]
// Test current
t2 := eLong.Cur.offset - e.cur - l
off := s - t2
if off < maxMatchOffset {
if off > 0 && t2 >= 0 {
if l2 := e.matchlenLong(s, t2, src); l2 > l {
t = t2
l = l2
}
}
// Test next:
t2 = eLong.Prev.offset - e.cur - l
off := s - t2
if off > 0 && off < maxMatchOffset && t2 >= 0 {
if l2 := e.matchlenLong(s, t2, src); l2 > l {
t = t2
l = l2
}
}
}
}
// Extend backwards
for t > 0 && s > nextEmit && src[t-1] == src[s-1] {
s--
t--
l++
}
if nextEmit < s {
if false {
emitLiteral(dst, src[nextEmit:s])
} else {
for _, v := range src[nextEmit:s] {
dst.tokens[dst.n] = token(v)
dst.litHist[v]++
dst.n++
}
}
}
if false {
if t >= s {
panic(fmt.Sprintln("s-t", s, t))
}
if (s - t) > maxMatchOffset {
panic(fmt.Sprintln("mmo", s-t))
}
if l < baseMatchLength {
panic("bml")
}
}
dst.AddMatchLong(l, uint32(s-t-baseMatchOffset))
repeat = s - t
s += l
nextEmit = s
if nextS >= s {
s = nextS + 1
}
if s >= sLimit {
// Index after match end.
for i := nextS + 1; i < int32(len(src))-8; i += 2 {
cv := load6432(src, i)
e.table[hash4x64(cv, tableBits)] = tableEntry{offset: i + e.cur}
eLong := &e.bTable[hash7(cv, tableBits)]
eLong.Cur, eLong.Prev = tableEntry{offset: i + e.cur}, eLong.Cur
}
goto emitRemainder
}
// Store every long hash in-between and every second short.
if true {
for i := nextS + 1; i < s-1; i += 2 {
cv := load6432(src, i)
t := tableEntry{offset: i + e.cur}
t2 := tableEntry{offset: t.offset + 1}
eLong := &e.bTable[hash7(cv, tableBits)]
eLong2 := &e.bTable[hash7(cv>>8, tableBits)]
e.table[hash4x64(cv, tableBits)] = t
eLong.Cur, eLong.Prev = t, eLong.Cur
eLong2.Cur, eLong2.Prev = t2, eLong2.Cur
}
}
// We could immediately start working at s now, but to improve
// compression we first update the hash table at s-1 and at s.
cv = load6432(src, s)
}
emitRemainder:
if int(nextEmit) < len(src) {
// If nothing was added, don't encode literals.
if dst.n == 0 {
return
}
emitLiteral(dst, src[nextEmit:])
}
}

37
src/cmd/linuxkit/vendor/github.com/klauspost/compress/flate/regmask_amd64.go generated vendored Normal file
View File

@@ -0,0 +1,37 @@
package flate
const (
// Masks for shifts with register sizes of the shift value.
// This can be used to work around the x86 design of shifting by mod register size.
// It can be used when a variable shift is always smaller than the register size.
// reg8SizeMaskX - shift value is 8 bits, shifted is X
reg8SizeMask8 = 7
reg8SizeMask16 = 15
reg8SizeMask32 = 31
reg8SizeMask64 = 63
// reg16SizeMaskX - shift value is 16 bits, shifted is X
reg16SizeMask8 = reg8SizeMask8
reg16SizeMask16 = reg8SizeMask16
reg16SizeMask32 = reg8SizeMask32
reg16SizeMask64 = reg8SizeMask64
// reg32SizeMaskX - shift value is 32 bits, shifted is X
reg32SizeMask8 = reg8SizeMask8
reg32SizeMask16 = reg8SizeMask16
reg32SizeMask32 = reg8SizeMask32
reg32SizeMask64 = reg8SizeMask64
// reg64SizeMaskX - shift value is 64 bits, shifted is X
reg64SizeMask8 = reg8SizeMask8
reg64SizeMask16 = reg8SizeMask16
reg64SizeMask32 = reg8SizeMask32
reg64SizeMask64 = reg8SizeMask64
// regSizeMaskUintX - shift value is uint, shifted is X
regSizeMaskUint8 = reg8SizeMask8
regSizeMaskUint16 = reg8SizeMask16
regSizeMaskUint32 = reg8SizeMask32
regSizeMaskUint64 = reg8SizeMask64
)

40
src/cmd/linuxkit/vendor/github.com/klauspost/compress/flate/regmask_other.go generated vendored Normal file
View File

@@ -0,0 +1,40 @@
//go:build !amd64
// +build !amd64
package flate
const (
// Masks for shifts with register sizes of the shift value.
// This can be used to work around the x86 design of shifting by mod register size.
// It can be used when a variable shift is always smaller than the register size.
// reg8SizeMaskX - shift value is 8 bits, shifted is X
reg8SizeMask8 = 0xff
reg8SizeMask16 = 0xff
reg8SizeMask32 = 0xff
reg8SizeMask64 = 0xff
// reg16SizeMaskX - shift value is 16 bits, shifted is X
reg16SizeMask8 = 0xffff
reg16SizeMask16 = 0xffff
reg16SizeMask32 = 0xffff
reg16SizeMask64 = 0xffff
// reg32SizeMaskX - shift value is 32 bits, shifted is X
reg32SizeMask8 = 0xffffffff
reg32SizeMask16 = 0xffffffff
reg32SizeMask32 = 0xffffffff
reg32SizeMask64 = 0xffffffff
// reg64SizeMaskX - shift value is 64 bits, shifted is X
reg64SizeMask8 = 0xffffffffffffffff
reg64SizeMask16 = 0xffffffffffffffff
reg64SizeMask32 = 0xffffffffffffffff
reg64SizeMask64 = 0xffffffffffffffff
// regSizeMaskUintX - shift value is uint, shifted is X
regSizeMaskUint8 = ^uint(0)
regSizeMaskUint16 = ^uint(0)
regSizeMaskUint32 = ^uint(0)
regSizeMaskUint64 = ^uint(0)
)

305
src/cmd/linuxkit/vendor/github.com/klauspost/compress/flate/stateless.go generated vendored Normal file
View File

@@ -0,0 +1,305 @@
package flate
import (
"io"
"math"
"sync"
)
const (
maxStatelessBlock = math.MaxInt16
// dictionary will be taken from maxStatelessBlock, so limit it.
maxStatelessDict = 8 << 10
slTableBits = 13
slTableSize = 1 << slTableBits
slTableShift = 32 - slTableBits
)
type statelessWriter struct {
dst io.Writer
closed bool
}
func (s *statelessWriter) Close() error {
if s.closed {
return nil
}
s.closed = true
// Emit EOF block
return StatelessDeflate(s.dst, nil, true, nil)
}
func (s *statelessWriter) Write(p []byte) (n int, err error) {
err = StatelessDeflate(s.dst, p, false, nil)
if err != nil {
return 0, err
}
return len(p), nil
}
func (s *statelessWriter) Reset(w io.Writer) {
s.dst = w
s.closed = false
}
// NewStatelessWriter will do compression but without maintaining any state
// between Write calls.
// There will be no memory kept between Write calls,
// but compression and speed will be suboptimal.
// Because of this, the size of actual Write calls will affect output size.
func NewStatelessWriter(dst io.Writer) io.WriteCloser {
return &statelessWriter{dst: dst}
}
// bitWriterPool contains bit writers that can be reused.
var bitWriterPool = sync.Pool{
New: func() interface{} {
return newHuffmanBitWriter(nil)
},
}
// StatelessDeflate allows to compress directly to a Writer without retaining state.
// When returning everything will be flushed.
// Up to 8KB of an optional dictionary can be given which is presumed to presumed to precede the block.
// Longer dictionaries will be truncated and will still produce valid output.
// Sending nil dictionary is perfectly fine.
func StatelessDeflate(out io.Writer, in []byte, eof bool, dict []byte) error {
var dst tokens
bw := bitWriterPool.Get().(*huffmanBitWriter)
bw.reset(out)
defer func() {
// don't keep a reference to our output
bw.reset(nil)
bitWriterPool.Put(bw)
}()
if eof && len(in) == 0 {
// Just write an EOF block.
// Could be faster...
bw.writeStoredHeader(0, true)
bw.flush()
return bw.err
}
// Truncate dict
if len(dict) > maxStatelessDict {
dict = dict[len(dict)-maxStatelessDict:]
}
for len(in) > 0 {
todo := in
if len(todo) > maxStatelessBlock-len(dict) {
todo = todo[:maxStatelessBlock-len(dict)]
}
in = in[len(todo):]
uncompressed := todo
if len(dict) > 0 {
// combine dict and source
bufLen := len(todo) + len(dict)
combined := make([]byte, bufLen)
copy(combined, dict)
copy(combined[len(dict):], todo)
todo = combined
}
// Compress
statelessEnc(&dst, todo, int16(len(dict)))
isEof := eof && len(in) == 0
if dst.n == 0 {
bw.writeStoredHeader(len(uncompressed), isEof)
if bw.err != nil {
return bw.err
}
bw.writeBytes(uncompressed)
} else if int(dst.n) > len(uncompressed)-len(uncompressed)>>4 {
// If we removed less than 1/16th, huffman compress the block.
bw.writeBlockHuff(isEof, uncompressed, len(in) == 0)
} else {
bw.writeBlockDynamic(&dst, isEof, uncompressed, len(in) == 0)
}
if len(in) > 0 {
// Retain a dict if we have more
dict = todo[len(todo)-maxStatelessDict:]
dst.Reset()
}
if bw.err != nil {
return bw.err
}
}
if !eof {
// Align, only a stored block can do that.
bw.writeStoredHeader(0, false)
}
bw.flush()
return bw.err
}
func hashSL(u uint32) uint32 {
return (u * 0x1e35a7bd) >> slTableShift
}
func load3216(b []byte, i int16) uint32 {
// Help the compiler eliminate bounds checks on the read so it can be done in a single read.
b = b[i:]
b = b[:4]
return uint32(b[0]) | uint32(b[1])<<8 | uint32(b[2])<<16 | uint32(b[3])<<24
}
func load6416(b []byte, i int16) uint64 {
// Help the compiler eliminate bounds checks on the read so it can be done in a single read.
b = b[i:]
b = b[:8]
return uint64(b[0]) | uint64(b[1])<<8 | uint64(b[2])<<16 | uint64(b[3])<<24 |
uint64(b[4])<<32 | uint64(b[5])<<40 | uint64(b[6])<<48 | uint64(b[7])<<56
}
func statelessEnc(dst *tokens, src []byte, startAt int16) {
const (
inputMargin = 12 - 1
minNonLiteralBlockSize = 1 + 1 + inputMargin
)
type tableEntry struct {
offset int16
}
var table [slTableSize]tableEntry
// This check isn't in the Snappy implementation, but there, the caller
// instead of the callee handles this case.
if len(src)-int(startAt) < minNonLiteralBlockSize {
// We do not fill the token table.
// This will be picked up by caller.
dst.n = 0
return
}
// Index until startAt
if startAt > 0 {
cv := load3232(src, 0)
for i := int16(0); i < startAt; i++ {
table[hashSL(cv)] = tableEntry{offset: i}
cv = (cv >> 8) | (uint32(src[i+4]) << 24)
}
}
s := startAt + 1
nextEmit := startAt
// sLimit is when to stop looking for offset/length copies. The inputMargin
// lets us use a fast path for emitLiteral in the main loop, while we are
// looking for copies.
sLimit := int16(len(src) - inputMargin)
// nextEmit is where in src the next emitLiteral should start from.
cv := load3216(src, s)
for {
const skipLog = 5
const doEvery = 2
nextS := s
var candidate tableEntry
for {
nextHash := hashSL(cv)
candidate = table[nextHash]
nextS = s + doEvery + (s-nextEmit)>>skipLog
if nextS > sLimit || nextS <= 0 {
goto emitRemainder
}
now := load6416(src, nextS)
table[nextHash] = tableEntry{offset: s}
nextHash = hashSL(uint32(now))
if cv == load3216(src, candidate.offset) {
table[nextHash] = tableEntry{offset: nextS}
break
}
// Do one right away...
cv = uint32(now)
s = nextS
nextS++
candidate = table[nextHash]
now >>= 8
table[nextHash] = tableEntry{offset: s}
if cv == load3216(src, candidate.offset) {
table[nextHash] = tableEntry{offset: nextS}
break
}
cv = uint32(now)
s = nextS
}
// A 4-byte match has been found. We'll later see if more than 4 bytes
// match. But, prior to the match, src[nextEmit:s] are unmatched. Emit
// them as literal bytes.
for {
// Invariant: we have a 4-byte match at s, and no need to emit any
// literal bytes prior to s.
// Extend the 4-byte match as long as possible.
t := candidate.offset
l := int16(matchLen(src[s+4:], src[t+4:]) + 4)
// Extend backwards
for t > 0 && s > nextEmit && src[t-1] == src[s-1] {
s--
t--
l++
}
if nextEmit < s {
if false {
emitLiteral(dst, src[nextEmit:s])
} else {
for _, v := range src[nextEmit:s] {
dst.tokens[dst.n] = token(v)
dst.litHist[v]++
dst.n++
}
}
}
// Save the match found
dst.AddMatchLong(int32(l), uint32(s-t-baseMatchOffset))
s += l
nextEmit = s
if nextS >= s {
s = nextS + 1
}
if s >= sLimit {
goto emitRemainder
}
// We could immediately start working at s now, but to improve
// compression we first update the hash table at s-2 and at s. If
// another emitCopy is not our next move, also calculate nextHash
// at s+1. At least on GOARCH=amd64, these three hash calculations
// are faster as one load64 call (with some shifts) instead of
// three load32 calls.
x := load6416(src, s-2)
o := s - 2
prevHash := hashSL(uint32(x))
table[prevHash] = tableEntry{offset: o}
x >>= 16
currHash := hashSL(uint32(x))
candidate = table[currHash]
table[currHash] = tableEntry{offset: o + 2}
if uint32(x) != load3216(src, candidate.offset) {
cv = uint32(x >> 8)
s++
break
}
}
}
emitRemainder:
if int(nextEmit) < len(src) {
// If nothing was added, don't encode literals.
if dst.n == 0 {
return
}
emitLiteral(dst, src[nextEmit:])
}
}

379
src/cmd/linuxkit/vendor/github.com/klauspost/compress/flate/token.go generated vendored Normal file
View File

@@ -0,0 +1,379 @@
// 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 flate
import (
"bytes"
"encoding/binary"
"fmt"
"io"
"math"
)
const (
// 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
literalType = 0 << 30
matchType = 1 << 30
matchOffsetOnlyMask = 0xffff
)
// The length code for length X (MIN_MATCH_LENGTH <= X <= MAX_MATCH_LENGTH)
// is lengthCodes[length - MIN_MATCH_LENGTH]
var lengthCodes = [256]uint8{
0, 1, 2, 3, 4, 5, 6, 7, 8, 8,
9, 9, 10, 10, 11, 11, 12, 12, 12, 12,
13, 13, 13, 13, 14, 14, 14, 14, 15, 15,
15, 15, 16, 16, 16, 16, 16, 16, 16, 16,
17, 17, 17, 17, 17, 17, 17, 17, 18, 18,
18, 18, 18, 18, 18, 18, 19, 19, 19, 19,
19, 19, 19, 19, 20, 20, 20, 20, 20, 20,
20, 20, 20, 20, 20, 20, 20, 20, 20, 20,
21, 21, 21, 21, 21, 21, 21, 21, 21, 21,
21, 21, 21, 21, 21, 21, 22, 22, 22, 22,
22, 22, 22, 22, 22, 22, 22, 22, 22, 22,
22, 22, 23, 23, 23, 23, 23, 23, 23, 23,
23, 23, 23, 23, 23, 23, 23, 23, 24, 24,
24, 24, 24, 24, 24, 24, 24, 24, 24, 24,
24, 24, 24, 24, 24, 24, 24, 24, 24, 24,
24, 24, 24, 24, 24, 24, 24, 24, 24, 24,
25, 25, 25, 25, 25, 25, 25, 25, 25, 25,
25, 25, 25, 25, 25, 25, 25, 25, 25, 25,
25, 25, 25, 25, 25, 25, 25, 25, 25, 25,
25, 25, 26, 26, 26, 26, 26, 26, 26, 26,
26, 26, 26, 26, 26, 26, 26, 26, 26, 26,
26, 26, 26, 26, 26, 26, 26, 26, 26, 26,
26, 26, 26, 26, 27, 27, 27, 27, 27, 27,
27, 27, 27, 27, 27, 27, 27, 27, 27, 27,
27, 27, 27, 27, 27, 27, 27, 27, 27, 27,
27, 27, 27, 27, 27, 28,
}
// lengthCodes1 is length codes, but starting at 1.
var lengthCodes1 = [256]uint8{
1, 2, 3, 4, 5, 6, 7, 8, 9, 9,
10, 10, 11, 11, 12, 12, 13, 13, 13, 13,
14, 14, 14, 14, 15, 15, 15, 15, 16, 16,
16, 16, 17, 17, 17, 17, 17, 17, 17, 17,
18, 18, 18, 18, 18, 18, 18, 18, 19, 19,
19, 19, 19, 19, 19, 19, 20, 20, 20, 20,
20, 20, 20, 20, 21, 21, 21, 21, 21, 21,
21, 21, 21, 21, 21, 21, 21, 21, 21, 21,
22, 22, 22, 22, 22, 22, 22, 22, 22, 22,
22, 22, 22, 22, 22, 22, 23, 23, 23, 23,
23, 23, 23, 23, 23, 23, 23, 23, 23, 23,
23, 23, 24, 24, 24, 24, 24, 24, 24, 24,
24, 24, 24, 24, 24, 24, 24, 24, 25, 25,
25, 25, 25, 25, 25, 25, 25, 25, 25, 25,
25, 25, 25, 25, 25, 25, 25, 25, 25, 25,
25, 25, 25, 25, 25, 25, 25, 25, 25, 25,
26, 26, 26, 26, 26, 26, 26, 26, 26, 26,
26, 26, 26, 26, 26, 26, 26, 26, 26, 26,
26, 26, 26, 26, 26, 26, 26, 26, 26, 26,
26, 26, 27, 27, 27, 27, 27, 27, 27, 27,
27, 27, 27, 27, 27, 27, 27, 27, 27, 27,
27, 27, 27, 27, 27, 27, 27, 27, 27, 27,
27, 27, 27, 27, 28, 28, 28, 28, 28, 28,
28, 28, 28, 28, 28, 28, 28, 28, 28, 28,
28, 28, 28, 28, 28, 28, 28, 28, 28, 28,
28, 28, 28, 28, 28, 29,
}
var offsetCodes = [256]uint32{
0, 1, 2, 3, 4, 4, 5, 5, 6, 6, 6, 6, 7, 7, 7, 7,
8, 8, 8, 8, 8, 8, 8, 8, 9, 9, 9, 9, 9, 9, 9, 9,
10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10,
11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11,
12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12,
12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12,
13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13,
13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13,
14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14,
14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14,
14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14,
14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14,
15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15,
15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15,
15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15,
15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15,
}
// offsetCodes14 are offsetCodes, but with 14 added.
var offsetCodes14 = [256]uint32{
14, 15, 16, 17, 18, 18, 19, 19, 20, 20, 20, 20, 21, 21, 21, 21,
22, 22, 22, 22, 22, 22, 22, 22, 23, 23, 23, 23, 23, 23, 23, 23,
24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24,
25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25,
26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26,
26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26,
27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27,
27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27,
28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28,
28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28,
28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28,
28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28,
29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29,
29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29,
29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29,
29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29,
}
type token uint32
type tokens struct {
extraHist [32]uint16 // codes 256->maxnumlit
offHist [32]uint16 // offset codes
litHist [256]uint16 // codes 0->255
nFilled int
n uint16 // Must be able to contain maxStoreBlockSize
tokens [maxStoreBlockSize + 1]token
}
func (t *tokens) Reset() {
if t.n == 0 {
return
}
t.n = 0
t.nFilled = 0
for i := range t.litHist[:] {
t.litHist[i] = 0
}
for i := range t.extraHist[:] {
t.extraHist[i] = 0
}
for i := range t.offHist[:] {
t.offHist[i] = 0
}
}
func (t *tokens) Fill() {
if t.n == 0 {
return
}
for i, v := range t.litHist[:] {
if v == 0 {
t.litHist[i] = 1
t.nFilled++
}
}
for i, v := range t.extraHist[:literalCount-256] {
if v == 0 {
t.nFilled++
t.extraHist[i] = 1
}
}
for i, v := range t.offHist[:offsetCodeCount] {
if v == 0 {
t.offHist[i] = 1
}
}
}
func indexTokens(in []token) tokens {
var t tokens
t.indexTokens(in)
return t
}
func (t *tokens) indexTokens(in []token) {
t.Reset()
for _, tok := range in {
if tok < matchType {
t.AddLiteral(tok.literal())
continue
}
t.AddMatch(uint32(tok.length()), tok.offset()&matchOffsetOnlyMask)
}
}
// emitLiteral writes a literal chunk and returns the number of bytes written.
func emitLiteral(dst *tokens, lit []byte) {
for _, v := range lit {
dst.tokens[dst.n] = token(v)
dst.litHist[v]++
dst.n++
}
}
func (t *tokens) AddLiteral(lit byte) {
t.tokens[t.n] = token(lit)
t.litHist[lit]++
t.n++
}
// from https://stackoverflow.com/a/28730362
func mFastLog2(val float32) float32 {
ux := int32(math.Float32bits(val))
log2 := (float32)(((ux >> 23) & 255) - 128)
ux &= -0x7f800001
ux += 127 << 23
uval := math.Float32frombits(uint32(ux))
log2 += ((-0.34484843)*uval+2.02466578)*uval - 0.67487759
return log2
}
// EstimatedBits will return an minimum size estimated by an *optimal*
// compression of the block.
// The size of the block
func (t *tokens) EstimatedBits() int {
shannon := float32(0)
bits := int(0)
nMatches := 0
total := int(t.n) + t.nFilled
if total > 0 {
invTotal := 1.0 / float32(total)
for _, v := range t.litHist[:] {
if v > 0 {
n := float32(v)
shannon += atLeastOne(-mFastLog2(n*invTotal)) * n
}
}
// Just add 15 for EOB
shannon += 15
for i, v := range t.extraHist[1 : literalCount-256] {
if v > 0 {
n := float32(v)
shannon += atLeastOne(-mFastLog2(n*invTotal)) * n
bits += int(lengthExtraBits[i&31]) * int(v)
nMatches += int(v)
}
}
}
if nMatches > 0 {
invTotal := 1.0 / float32(nMatches)
for i, v := range t.offHist[:offsetCodeCount] {
if v > 0 {
n := float32(v)
shannon += atLeastOne(-mFastLog2(n*invTotal)) * n
bits += int(offsetExtraBits[i&31]) * int(v)
}
}
}
return int(shannon) + bits
}
// AddMatch adds a match to the tokens.
// This function is very sensitive to inlining and right on the border.
func (t *tokens) AddMatch(xlength uint32, xoffset uint32) {
if debugDeflate {
if xlength >= maxMatchLength+baseMatchLength {
panic(fmt.Errorf("invalid length: %v", xlength))
}
if xoffset >= maxMatchOffset+baseMatchOffset {
panic(fmt.Errorf("invalid offset: %v", xoffset))
}
}
oCode := offsetCode(xoffset)
xoffset |= oCode << 16
t.extraHist[lengthCodes1[uint8(xlength)]]++
t.offHist[oCode&31]++
t.tokens[t.n] = token(matchType | xlength<<lengthShift | xoffset)
t.n++
}
// AddMatchLong adds a match to the tokens, potentially longer than max match length.
// Length should NOT have the base subtracted, only offset should.
func (t *tokens) AddMatchLong(xlength int32, xoffset uint32) {
if debugDeflate {
if xoffset >= maxMatchOffset+baseMatchOffset {
panic(fmt.Errorf("invalid offset: %v", xoffset))
}
}
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.
if xl > 258+baseMatchLength {
xl = 258
} else {
xl = 258 - baseMatchLength
}
}
xlength -= xl
xl -= baseMatchLength
t.extraHist[lengthCodes1[uint8(xl)]]++
t.offHist[oc&31]++
t.tokens[t.n] = token(matchType | uint32(xl)<<lengthShift | xoffset)
t.n++
}
}
func (t *tokens) AddEOB() {
t.tokens[t.n] = token(endBlockMarker)
t.extraHist[0]++
t.n++
}
func (t *tokens) Slice() []token {
return t.tokens[:t.n]
}
// VarInt returns the tokens as varint encoded bytes.
func (t *tokens) VarInt() []byte {
var b = make([]byte, binary.MaxVarintLen32*int(t.n))
var off int
for _, v := range t.tokens[:t.n] {
off += binary.PutUvarint(b[off:], uint64(v))
}
return b[:off]
}
// FromVarInt restores t to the varint encoded tokens provided.
// Any data in t is removed.
func (t *tokens) FromVarInt(b []byte) error {
var buf = bytes.NewReader(b)
var toks []token
for {
r, err := binary.ReadUvarint(buf)
if err == io.EOF {
break
}
if err != nil {
return err
}
toks = append(toks, token(r))
}
t.indexTokens(toks)
return nil
}
// Returns the type of a token
func (t token) typ() uint32 { return uint32(t) & typeMask }
// Returns the literal of a literal token
func (t token) literal() uint8 { return uint8(t) }
// Returns the extra offset of a match token
func (t token) offset() uint32 { return uint32(t) & offsetMask }
func (t token) length() uint8 { return uint8(t >> lengthShift) }
// 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 {
if false {
if off < uint32(len(offsetCodes)) {
return offsetCodes[off&255]
} else if off>>7 < uint32(len(offsetCodes)) {
return offsetCodes[(off>>7)&255] + 14
} else {
return offsetCodes[(off>>14)&255] + 28
}
}
if off < uint32(len(offsetCodes)) {
return offsetCodes[uint8(off)]
}
return offsetCodes14[uint8(off>>7)]
}

24
src/cmd/linuxkit/vendor/github.com/klauspost/pgzip/.gitignore generated vendored Normal file
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@@ -0,0 +1,24 @@
# Compiled Object files, Static and Dynamic libs (Shared Objects)
*.o
*.a
*.so
# Folders
_obj
_test
# Architecture specific extensions/prefixes
*.[568vq]
[568vq].out
*.cgo1.go
*.cgo2.c
_cgo_defun.c
_cgo_gotypes.go
_cgo_export.*
_testmain.go
*.exe
*.test
*.prof

24
src/cmd/linuxkit/vendor/github.com/klauspost/pgzip/.travis.yml generated vendored Normal file
View File

@@ -0,0 +1,24 @@
language: go
os:
- linux
- osx
go:
- 1.13.x
- 1.14.x
- 1.15.x
- master
env:
- GO111MODULE=off
script:
- diff <(gofmt -d .) <(printf "")
- go test -v -cpu=1,2,4 .
- go test -v -cpu=2 -race -short .
matrix:
allow_failures:
- go: 'master'
fast_finish: true

27
src/cmd/linuxkit/vendor/github.com/klauspost/pgzip/GO_LICENSE generated vendored Normal file
View File

@@ -0,0 +1,27 @@
Copyright (c) 2012 The Go Authors. All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:
* Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above
copyright notice, this list of conditions and the following disclaimer
in the documentation and/or other materials provided with the
distribution.
* Neither the name of Google Inc. nor the names of its
contributors may be used to endorse or promote products derived from
this software without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

21
src/cmd/linuxkit/vendor/github.com/klauspost/pgzip/LICENSE generated vendored Normal file
View File

@@ -0,0 +1,21 @@
MIT License
Copyright (c) 2014 Klaus Post
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.

135
src/cmd/linuxkit/vendor/github.com/klauspost/pgzip/README.md generated vendored Normal file
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@@ -0,0 +1,135 @@
pgzip
=====
Go parallel gzip compression/decompression. This is a fully gzip compatible drop in replacement for "compress/gzip".
This will split compression into blocks that are compressed in parallel.
This can be useful for compressing big amounts of data. The output is a standard gzip file.
The gzip decompression is modified so it decompresses ahead of the current reader.
This means that reads will be non-blocking if the decompressor can keep ahead of your code reading from it.
CRC calculation also takes place in a separate goroutine.
You should only use this if you are (de)compressing big amounts of data,
say **more than 1MB** at the time, otherwise you will not see any benefit,
and it will likely be faster to use the internal gzip library
or [this package](https://github.com/klauspost/compress).
It is important to note that this library creates and reads *standard gzip files*.
You do not have to match the compressor/decompressor to get the described speedups,
and the gzip files are fully compatible with other gzip readers/writers.
A golang variant of this is [bgzf](https://godoc.org/github.com/biogo/hts/bgzf),
which has the same feature, as well as seeking in the resulting file.
The only drawback is a slightly bigger overhead compared to this and pure gzip.
See a comparison below.
[![GoDoc][1]][2] [![Build Status][3]][4]
[1]: https://godoc.org/github.com/klauspost/pgzip?status.svg
[2]: https://godoc.org/github.com/klauspost/pgzip
[3]: https://travis-ci.org/klauspost/pgzip.svg
[4]: https://travis-ci.org/klauspost/pgzip
Installation
====
```go get github.com/klauspost/pgzip/...```
You might need to get/update the dependencies:
```
go get -u github.com/klauspost/compress
```
Usage
====
[Godoc Doumentation](https://godoc.org/github.com/klauspost/pgzip)
To use as a replacement for gzip, exchange
```import "compress/gzip"```
with
```import gzip "github.com/klauspost/pgzip"```.
# Changes
* Oct 6, 2016: Fixed an issue if the destination writer returned an error.
* Oct 6, 2016: Better buffer reuse, should now generate less garbage.
* Oct 6, 2016: Output does not change based on write sizes.
* Dec 8, 2015: Decoder now supports the io.WriterTo interface, giving a speedup and less GC pressure.
* Oct 9, 2015: Reduced allocations by ~35 by using sync.Pool. ~15% overall speedup.
Changes in [github.com/klauspost/compress](https://github.com/klauspost/compress#changelog) are also carried over, so see that for more changes.
## Compression
The simplest way to use this is to simply do the same as you would when using [compress/gzip](http://golang.org/pkg/compress/gzip).
To change the block size, use the added (*pgzip.Writer).SetConcurrency(blockSize, blocks int) function. With this you can control the approximate size of your blocks, as well as how many you want to be processing in parallel. Default values for this is SetConcurrency(1MB, runtime.GOMAXPROCS(0)), meaning blocks are split at 1 MB and up to the number of CPU threads blocks can be processing at once before the writer blocks.
Example:
```
var b bytes.Buffer
w := gzip.NewWriter(&b)
w.SetConcurrency(100000, 10)
w.Write([]byte("hello, world\n"))
w.Close()
```
To get any performance gains, you should at least be compressing more than 1 megabyte of data at the time.
You should at least have a block size of 100k and at least a number of blocks that match the number of cores your would like to utilize, but about twice the number of blocks would be the best.
Another side effect of this is, that it is likely to speed up your other code, since writes to the compressor only blocks if the compressor is already compressing the number of blocks you have specified. This also means you don't have worry about buffering input to the compressor.
## Decompression
Decompression works similar to compression. That means that you simply call pgzip the same way as you would call [compress/gzip](http://golang.org/pkg/compress/gzip).
The only difference is that if you want to specify your own readahead, you have to use `pgzip.NewReaderN(r io.Reader, blockSize, blocks int)` to get a reader with your custom blocksizes. The `blockSize` is the size of each block decoded, and `blocks` is the maximum number of blocks that is decoded ahead.
See [Example on playground](http://play.golang.org/p/uHv1B5NbDh)
Performance
====
## Compression
See my blog post in [Benchmarks of Golang Gzip](https://blog.klauspost.com/go-gzipdeflate-benchmarks/).
Compression cost is usually about 0.2% with default settings with a block size of 250k.
Example with GOMAXPROC set to 32 (16 core CPU)
Content is [Matt Mahoneys 10GB corpus](http://mattmahoney.net/dc/10gb.html). Compression level 6.
Compressor | MB/sec | speedup | size | size overhead (lower=better)
------------|----------|---------|------|---------
[gzip](http://golang.org/pkg/compress/gzip) (golang) | 15.44MB/s (1 thread) | 1.0x | 4781329307 | 0%
[gzip](http://github.com/klauspost/compress/gzip) (klauspost) | 135.04MB/s (1 thread) | 8.74x | 4894858258 | +2.37%
[pgzip](https://github.com/klauspost/pgzip) (klauspost) | 1573.23MB/s| 101.9x | 4902285651 | +2.53%
[bgzf](https://godoc.org/github.com/biogo/hts/bgzf) (biogo) | 361.40MB/s | 23.4x | 4869686090 | +1.85%
[pargzip](https://godoc.org/github.com/golang/build/pargzip) (builder) | 306.01MB/s | 19.8x | 4786890417 | +0.12%
pgzip also contains a [linear time compression](https://github.com/klauspost/compress#linear-time-compression-huffman-only) mode, that will allow compression at ~250MB per core per second, independent of the content.
See the [complete sheet](https://docs.google.com/spreadsheets/d/1nuNE2nPfuINCZJRMt6wFWhKpToF95I47XjSsc-1rbPQ/edit?usp=sharing) for different content types and compression settings.
## Decompression
The decompression speedup is there because it allows you to do other work while the decompression is taking place.
In the example above, the numbers are as follows on a 4 CPU machine:
Decompressor | Time | Speedup
-------------|------|--------
[gzip](http://golang.org/pkg/compress/gzip) (golang) | 1m28.85s | 0%
[pgzip](https://github.com/klauspost/pgzip) (golang) | 43.48s | 104%
But wait, since gzip decompression is inherently singlethreaded (aside from CRC calculation) how can it be more than 100% faster? Because pgzip due to its design also acts as a buffer. When using unbuffered gzip, you are also waiting for io when you are decompressing. If the gzip decoder can keep up, it will always have data ready for your reader, and you will not be waiting for input to the gzip decompressor to complete.
This is pretty much an optimal situation for pgzip, but it reflects most common usecases for CPU intensive gzip usage.
I haven't included [bgzf](https://godoc.org/github.com/biogo/hts/bgzf) in this comparison, since it only can decompress files created by a compatible encoder, and therefore cannot be considered a generic gzip decompressor. But if you are able to compress your files with a bgzf compatible program, you can expect it to scale beyond 100%.
# License
This contains large portions of code from the go repository - see GO_LICENSE for more information. The changes are released under MIT License. See LICENSE for more information.

584
src/cmd/linuxkit/vendor/github.com/klauspost/pgzip/gunzip.go generated vendored Normal file
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// 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 pgzip implements reading and writing of gzip format compressed files,
// as specified in RFC 1952.
//
// This is a drop in replacement for "compress/gzip".
// This will split compression into blocks that are compressed in parallel.
// This can be useful for compressing big amounts of data.
// The gzip decompression has not been modified, but remains in the package,
// so you can use it as a complete replacement for "compress/gzip".
//
// See more at https://github.com/klauspost/pgzip
package pgzip
import (
"bufio"
"errors"
"hash"
"hash/crc32"
"io"
"sync"
"time"
"github.com/klauspost/compress/flate"
)
const (
gzipID1 = 0x1f
gzipID2 = 0x8b
gzipDeflate = 8
flagText = 1 << 0
flagHdrCrc = 1 << 1
flagExtra = 1 << 2
flagName = 1 << 3
flagComment = 1 << 4
)
func makeReader(r io.Reader) flate.Reader {
if rr, ok := r.(flate.Reader); ok {
return rr
}
return bufio.NewReader(r)
}
var (
// ErrChecksum is returned when reading GZIP data that has an invalid checksum.
ErrChecksum = errors.New("gzip: invalid checksum")
// ErrHeader is returned when reading GZIP data that has an invalid header.
ErrHeader = errors.New("gzip: invalid header")
)
// The gzip file stores a header giving metadata about the compressed file.
// That header is exposed as the fields of the Writer and Reader structs.
type Header struct {
Comment string // comment
Extra []byte // "extra data"
ModTime time.Time // modification time
Name string // file name
OS byte // operating system type
}
// A Reader is an io.Reader that can be read to retrieve
// uncompressed data from a gzip-format compressed file.
//
// In general, a gzip file can be a concatenation of gzip files,
// each with its own header. Reads from the Reader
// return the concatenation of the uncompressed data of each.
// Only the first header is recorded in the Reader fields.
//
// Gzip files store a length and checksum of the uncompressed data.
// The Reader will return a ErrChecksum when Read
// reaches the end of the uncompressed data if it does not
// have the expected length or checksum. Clients should treat data
// returned by Read as tentative until they receive the io.EOF
// marking the end of the data.
type Reader struct {
Header
r flate.Reader
decompressor io.ReadCloser
digest hash.Hash32
size uint32
flg byte
buf [512]byte
err error
closeErr chan error
multistream bool
readAhead chan read
roff int // read offset
current []byte
closeReader chan struct{}
lastBlock bool
blockSize int
blocks int
activeRA bool // Indication if readahead is active
mu sync.Mutex // Lock for above
blockPool chan []byte
}
type read struct {
b []byte
err error
}
// NewReader creates a new Reader reading the given reader.
// The implementation buffers input and may read more data than necessary from r.
// It is the caller's responsibility to call Close on the Reader when done.
func NewReader(r io.Reader) (*Reader, error) {
z := new(Reader)
z.blocks = defaultBlocks
z.blockSize = defaultBlockSize
z.r = makeReader(r)
z.digest = crc32.NewIEEE()
z.multistream = true
z.blockPool = make(chan []byte, z.blocks)
for i := 0; i < z.blocks; i++ {
z.blockPool <- make([]byte, z.blockSize)
}
if err := z.readHeader(true); err != nil {
return nil, err
}
return z, nil
}
// NewReaderN creates a new Reader reading the given reader.
// The implementation buffers input and may read more data than necessary from r.
// It is the caller's responsibility to call Close on the Reader when done.
//
// With this you can control the approximate size of your blocks,
// as well as how many blocks you want to have prefetched.
//
// Default values for this is blockSize = 250000, blocks = 16,
// meaning up to 16 blocks of maximum 250000 bytes will be
// prefetched.
func NewReaderN(r io.Reader, blockSize, blocks int) (*Reader, error) {
z := new(Reader)
z.blocks = blocks
z.blockSize = blockSize
z.r = makeReader(r)
z.digest = crc32.NewIEEE()
z.multistream = true
// Account for too small values
if z.blocks <= 0 {
z.blocks = defaultBlocks
}
if z.blockSize <= 512 {
z.blockSize = defaultBlockSize
}
z.blockPool = make(chan []byte, z.blocks)
for i := 0; i < z.blocks; i++ {
z.blockPool <- make([]byte, z.blockSize)
}
if err := z.readHeader(true); err != nil {
return nil, err
}
return z, nil
}
// Reset discards the Reader z's state and makes it equivalent to the
// result of its original state from NewReader, but reading from r instead.
// This permits reusing a Reader rather than allocating a new one.
func (z *Reader) Reset(r io.Reader) error {
z.killReadAhead()
z.r = makeReader(r)
z.digest = crc32.NewIEEE()
z.size = 0
z.err = nil
z.multistream = true
// Account for uninitialized values
if z.blocks <= 0 {
z.blocks = defaultBlocks
}
if z.blockSize <= 512 {
z.blockSize = defaultBlockSize
}
if z.blockPool == nil {
z.blockPool = make(chan []byte, z.blocks)
for i := 0; i < z.blocks; i++ {
z.blockPool <- make([]byte, z.blockSize)
}
}
return z.readHeader(true)
}
// Multistream controls whether the reader supports multistream files.
//
// If enabled (the default), the Reader expects the input to be a sequence
// of individually gzipped data streams, each with its own header and
// trailer, ending at EOF. The effect is that the concatenation of a sequence
// of gzipped files is treated as equivalent to the gzip of the concatenation
// of the sequence. This is standard behavior for gzip readers.
//
// Calling Multistream(false) disables this behavior; disabling the behavior
// can be useful when reading file formats that distinguish individual gzip
// data streams or mix gzip data streams with other data streams.
// In this mode, when the Reader reaches the end of the data stream,
// Read returns io.EOF. If the underlying reader implements io.ByteReader,
// it will be left positioned just after the gzip stream.
// To start the next stream, call z.Reset(r) followed by z.Multistream(false).
// If there is no next stream, z.Reset(r) will return io.EOF.
func (z *Reader) Multistream(ok bool) {
z.multistream = ok
}
// GZIP (RFC 1952) is little-endian, unlike ZLIB (RFC 1950).
func get4(p []byte) uint32 {
return uint32(p[0]) | uint32(p[1])<<8 | uint32(p[2])<<16 | uint32(p[3])<<24
}
func (z *Reader) readString() (string, error) {
var err error
needconv := false
for i := 0; ; i++ {
if i >= len(z.buf) {
return "", ErrHeader
}
z.buf[i], err = z.r.ReadByte()
if err != nil {
return "", err
}
if z.buf[i] > 0x7f {
needconv = true
}
if z.buf[i] == 0 {
// GZIP (RFC 1952) specifies that strings are NUL-terminated ISO 8859-1 (Latin-1).
if needconv {
s := make([]rune, 0, i)
for _, v := range z.buf[0:i] {
s = append(s, rune(v))
}
return string(s), nil
}
return string(z.buf[0:i]), nil
}
}
}
func (z *Reader) read2() (uint32, error) {
_, err := io.ReadFull(z.r, z.buf[0:2])
if err != nil {
return 0, err
}
return uint32(z.buf[0]) | uint32(z.buf[1])<<8, nil
}
func (z *Reader) readHeader(save bool) error {
z.killReadAhead()
_, err := io.ReadFull(z.r, z.buf[0:10])
if err != nil {
return err
}
if z.buf[0] != gzipID1 || z.buf[1] != gzipID2 || z.buf[2] != gzipDeflate {
return ErrHeader
}
z.flg = z.buf[3]
if save {
z.ModTime = time.Unix(int64(get4(z.buf[4:8])), 0)
// z.buf[8] is xfl, ignored
z.OS = z.buf[9]
}
z.digest.Reset()
z.digest.Write(z.buf[0:10])
if z.flg&flagExtra != 0 {
n, err := z.read2()
if err != nil {
return err
}
data := make([]byte, n)
if _, err = io.ReadFull(z.r, data); err != nil {
return err
}
if save {
z.Extra = data
}
}
var s string
if z.flg&flagName != 0 {
if s, err = z.readString(); err != nil {
return err
}
if save {
z.Name = s
}
}
if z.flg&flagComment != 0 {
if s, err = z.readString(); err != nil {
return err
}
if save {
z.Comment = s
}
}
if z.flg&flagHdrCrc != 0 {
n, err := z.read2()
if err != nil {
return err
}
sum := z.digest.Sum32() & 0xFFFF
if n != sum {
return ErrHeader
}
}
z.digest.Reset()
z.decompressor = flate.NewReader(z.r)
z.doReadAhead()
return nil
}
func (z *Reader) killReadAhead() error {
z.mu.Lock()
defer z.mu.Unlock()
if z.activeRA {
if z.closeReader != nil {
close(z.closeReader)
}
// Wait for decompressor to be closed and return error, if any.
e, ok := <-z.closeErr
z.activeRA = false
for blk := range z.readAhead {
if blk.b != nil {
z.blockPool <- blk.b
}
}
if cap(z.current) > 0 {
z.blockPool <- z.current
z.current = nil
}
if !ok {
// Channel is closed, so if there was any error it has already been returned.
return nil
}
return e
}
return nil
}
// Starts readahead.
// Will return on error (including io.EOF)
// or when z.closeReader is closed.
func (z *Reader) doReadAhead() {
z.mu.Lock()
defer z.mu.Unlock()
z.activeRA = true
if z.blocks <= 0 {
z.blocks = defaultBlocks
}
if z.blockSize <= 512 {
z.blockSize = defaultBlockSize
}
ra := make(chan read, z.blocks)
z.readAhead = ra
closeReader := make(chan struct{}, 0)
z.closeReader = closeReader
z.lastBlock = false
closeErr := make(chan error, 1)
z.closeErr = closeErr
z.size = 0
z.roff = 0
z.current = nil
decomp := z.decompressor
go func() {
defer func() {
closeErr <- decomp.Close()
close(closeErr)
close(ra)
}()
// We hold a local reference to digest, since
// it way be changed by reset.
digest := z.digest
var wg sync.WaitGroup
for {
var buf []byte
select {
case buf = <-z.blockPool:
case <-closeReader:
return
}
buf = buf[0:z.blockSize]
// Try to fill the buffer
n, err := io.ReadFull(decomp, buf)
if err == io.ErrUnexpectedEOF {
if n > 0 {
err = nil
} else {
// If we got zero bytes, we need to establish if
// we reached end of stream or truncated stream.
_, err = decomp.Read([]byte{})
if err == io.EOF {
err = nil
}
}
}
if n < len(buf) {
buf = buf[0:n]
}
wg.Wait()
wg.Add(1)
go func() {
digest.Write(buf)
wg.Done()
}()
z.size += uint32(n)
// If we return any error, out digest must be ready
if err != nil {
wg.Wait()
}
select {
case z.readAhead <- read{b: buf, err: err}:
case <-closeReader:
// Sent on close, we don't care about the next results
z.blockPool <- buf
return
}
if err != nil {
return
}
}
}()
}
func (z *Reader) Read(p []byte) (n int, err error) {
if z.err != nil {
return 0, z.err
}
if len(p) == 0 {
return 0, nil
}
for {
if len(z.current) == 0 && !z.lastBlock {
read := <-z.readAhead
if read.err != nil {
// If not nil, the reader will have exited
z.closeReader = nil
if read.err != io.EOF {
z.err = read.err
return
}
if read.err == io.EOF {
z.lastBlock = true
err = nil
}
}
z.current = read.b
z.roff = 0
}
avail := z.current[z.roff:]
if len(p) >= len(avail) {
// If len(p) >= len(current), return all content of current
n = copy(p, avail)
z.blockPool <- z.current
z.current = nil
if z.lastBlock {
err = io.EOF
break
}
} else {
// We copy as much as there is space for
n = copy(p, avail)
z.roff += n
}
return
}
// Finished file; check checksum + size.
if _, err := io.ReadFull(z.r, z.buf[0:8]); err != nil {
z.err = err
return 0, err
}
crc32, isize := get4(z.buf[0:4]), get4(z.buf[4:8])
sum := z.digest.Sum32()
if sum != crc32 || isize != z.size {
z.err = ErrChecksum
return 0, z.err
}
// File is ok; should we attempt reading one more?
if !z.multistream {
return 0, io.EOF
}
// Is there another?
if err = z.readHeader(false); err != nil {
z.err = err
return
}
// Yes. Reset and read from it.
return z.Read(p)
}
func (z *Reader) WriteTo(w io.Writer) (n int64, err error) {
total := int64(0)
for {
if z.err != nil {
return total, z.err
}
// We write both to output and digest.
for {
// Read from input
read := <-z.readAhead
if read.err != nil {
// If not nil, the reader will have exited
z.closeReader = nil
if read.err != io.EOF {
z.err = read.err
return total, z.err
}
if read.err == io.EOF {
z.lastBlock = true
err = nil
}
}
// Write what we got
n, err := w.Write(read.b)
if n != len(read.b) {
return total, io.ErrShortWrite
}
total += int64(n)
if err != nil {
return total, err
}
// Put block back
z.blockPool <- read.b
if z.lastBlock {
break
}
}
// Finished file; check checksum + size.
if _, err := io.ReadFull(z.r, z.buf[0:8]); err != nil {
z.err = err
return total, err
}
crc32, isize := get4(z.buf[0:4]), get4(z.buf[4:8])
sum := z.digest.Sum32()
if sum != crc32 || isize != z.size {
z.err = ErrChecksum
return total, z.err
}
// File is ok; should we attempt reading one more?
if !z.multistream {
return total, nil
}
// Is there another?
err = z.readHeader(false)
if err == io.EOF {
return total, nil
}
if err != nil {
z.err = err
return total, err
}
}
}
// Close closes the Reader. It does not close the underlying io.Reader.
func (z *Reader) Close() error {
return z.killReadAhead()
}

519
src/cmd/linuxkit/vendor/github.com/klauspost/pgzip/gzip.go generated vendored Normal file
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@@ -0,0 +1,519 @@
// Copyright 2010 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 pgzip
import (
"bytes"
"errors"
"fmt"
"hash"
"hash/crc32"
"io"
"runtime"
"sync"
"time"
"github.com/klauspost/compress/flate"
)
const (
defaultBlockSize = 1 << 20
tailSize = 16384
defaultBlocks = 4
)
// These constants are copied from the flate package, so that code that imports
// "compress/gzip" does not also have to import "compress/flate".
const (
NoCompression = flate.NoCompression
BestSpeed = flate.BestSpeed
BestCompression = flate.BestCompression
DefaultCompression = flate.DefaultCompression
ConstantCompression = flate.ConstantCompression
HuffmanOnly = flate.HuffmanOnly
)
// A Writer is an io.WriteCloser.
// Writes to a Writer are compressed and written to w.
type Writer struct {
Header
w io.Writer
level int
wroteHeader bool
blockSize int
blocks int
currentBuffer []byte
prevTail []byte
digest hash.Hash32
size int
closed bool
buf [10]byte
errMu sync.RWMutex
err error
pushedErr chan struct{}
results chan result
dictFlatePool sync.Pool
dstPool sync.Pool
wg sync.WaitGroup
}
type result struct {
result chan []byte
notifyWritten chan struct{}
}
// Use SetConcurrency to finetune the concurrency level if needed.
//
// With this you can control the approximate size of your blocks,
// as well as how many you want to be processing in parallel.
//
// Default values for this is SetConcurrency(defaultBlockSize, runtime.GOMAXPROCS(0)),
// meaning blocks are split at 1 MB and up to the number of CPU threads
// can be processing at once before the writer blocks.
func (z *Writer) SetConcurrency(blockSize, blocks int) error {
if blockSize <= tailSize {
return fmt.Errorf("gzip: block size cannot be less than or equal to %d", tailSize)
}
if blocks <= 0 {
return errors.New("gzip: blocks cannot be zero or less")
}
if blockSize == z.blockSize && blocks == z.blocks {
return nil
}
z.blockSize = blockSize
z.results = make(chan result, blocks)
z.blocks = blocks
z.dstPool.New = func() interface{} { return make([]byte, 0, blockSize+(blockSize)>>4) }
return nil
}
// NewWriter returns a new Writer.
// Writes to the returned writer are compressed and written to w.
//
// It is the caller's responsibility to call Close on the WriteCloser when done.
// Writes may be buffered and not flushed until Close.
//
// Callers that wish to set the fields in Writer.Header must do so before
// the first call to Write or Close. The Comment and Name header fields are
// UTF-8 strings in Go, but the underlying format requires NUL-terminated ISO
// 8859-1 (Latin-1). NUL or non-Latin-1 runes in those strings will lead to an
// error on Write.
func NewWriter(w io.Writer) *Writer {
z, _ := NewWriterLevel(w, DefaultCompression)
return z
}
// NewWriterLevel is like NewWriter but specifies the compression level instead
// of assuming DefaultCompression.
//
// The compression level can be DefaultCompression, NoCompression, or any
// integer value between BestSpeed and BestCompression inclusive. The error
// returned will be nil if the level is valid.
func NewWriterLevel(w io.Writer, level int) (*Writer, error) {
if level < ConstantCompression || level > BestCompression {
return nil, fmt.Errorf("gzip: invalid compression level: %d", level)
}
z := new(Writer)
z.SetConcurrency(defaultBlockSize, runtime.GOMAXPROCS(0))
z.init(w, level)
return z, nil
}
// This function must be used by goroutines to set an
// error condition, since z.err access is restricted
// to the callers goruotine.
func (z *Writer) pushError(err error) {
z.errMu.Lock()
if z.err != nil {
z.errMu.Unlock()
return
}
z.err = err
close(z.pushedErr)
z.errMu.Unlock()
}
func (z *Writer) init(w io.Writer, level int) {
z.wg.Wait()
digest := z.digest
if digest != nil {
digest.Reset()
} else {
digest = crc32.NewIEEE()
}
z.Header = Header{OS: 255}
z.w = w
z.level = level
z.digest = digest
z.pushedErr = make(chan struct{}, 0)
z.results = make(chan result, z.blocks)
z.err = nil
z.closed = false
z.Comment = ""
z.Extra = nil
z.ModTime = time.Time{}
z.wroteHeader = false
z.currentBuffer = nil
z.buf = [10]byte{}
z.prevTail = nil
z.size = 0
if z.dictFlatePool.New == nil {
z.dictFlatePool.New = func() interface{} {
f, _ := flate.NewWriterDict(w, level, nil)
return f
}
}
}
// Reset discards the Writer z's state and makes it equivalent to the
// result of its original state from NewWriter or NewWriterLevel, but
// writing to w instead. This permits reusing a Writer rather than
// allocating a new one.
func (z *Writer) Reset(w io.Writer) {
if z.results != nil && !z.closed {
close(z.results)
}
z.SetConcurrency(defaultBlockSize, runtime.GOMAXPROCS(0))
z.init(w, z.level)
}
// GZIP (RFC 1952) is little-endian, unlike ZLIB (RFC 1950).
func put2(p []byte, v uint16) {
p[0] = uint8(v >> 0)
p[1] = uint8(v >> 8)
}
func put4(p []byte, v uint32) {
p[0] = uint8(v >> 0)
p[1] = uint8(v >> 8)
p[2] = uint8(v >> 16)
p[3] = uint8(v >> 24)
}
// writeBytes writes a length-prefixed byte slice to z.w.
func (z *Writer) writeBytes(b []byte) error {
if len(b) > 0xffff {
return errors.New("gzip.Write: Extra data is too large")
}
put2(z.buf[0:2], uint16(len(b)))
_, err := z.w.Write(z.buf[0:2])
if err != nil {
return err
}
_, err = z.w.Write(b)
return err
}
// writeString writes a UTF-8 string s in GZIP's format to z.w.
// GZIP (RFC 1952) specifies that strings are NUL-terminated ISO 8859-1 (Latin-1).
func (z *Writer) writeString(s string) (err error) {
// GZIP stores Latin-1 strings; error if non-Latin-1; convert if non-ASCII.
needconv := false
for _, v := range s {
if v == 0 || v > 0xff {
return errors.New("gzip.Write: non-Latin-1 header string")
}
if v > 0x7f {
needconv = true
}
}
if needconv {
b := make([]byte, 0, len(s))
for _, v := range s {
b = append(b, byte(v))
}
_, err = z.w.Write(b)
} else {
_, err = io.WriteString(z.w, s)
}
if err != nil {
return err
}
// GZIP strings are NUL-terminated.
z.buf[0] = 0
_, err = z.w.Write(z.buf[0:1])
return err
}
// compressCurrent will compress the data currently buffered
// This should only be called from the main writer/flush/closer
func (z *Writer) compressCurrent(flush bool) {
c := z.currentBuffer
if len(c) > z.blockSize {
// This can never happen through the public interface.
panic("len(z.currentBuffer) > z.blockSize (most likely due to concurrent Write race)")
}
r := result{}
r.result = make(chan []byte, 1)
r.notifyWritten = make(chan struct{}, 0)
// Reserve a result slot
select {
case z.results <- r:
case <-z.pushedErr:
return
}
z.wg.Add(1)
tail := z.prevTail
if len(c) > tailSize {
buf := z.dstPool.Get().([]byte) // Put in .compressBlock
// Copy tail from current buffer before handing the buffer over to the
// compressBlock goroutine.
buf = append(buf[:0], c[len(c)-tailSize:]...)
z.prevTail = buf
} else {
z.prevTail = nil
}
go z.compressBlock(c, tail, r, z.closed)
z.currentBuffer = z.dstPool.Get().([]byte) // Put in .compressBlock
z.currentBuffer = z.currentBuffer[:0]
// Wait if flushing
if flush {
<-r.notifyWritten
}
}
// Returns an error if it has been set.
// Cannot be used by functions that are from internal goroutines.
func (z *Writer) checkError() error {
z.errMu.RLock()
err := z.err
z.errMu.RUnlock()
return err
}
// Write writes a compressed form of p to the underlying io.Writer. The
// compressed bytes are not necessarily flushed to output until
// the Writer is closed or Flush() is called.
//
// The function will return quickly, if there are unused buffers.
// The sent slice (p) is copied, and the caller is free to re-use the buffer
// when the function returns.
//
// Errors that occur during compression will be reported later, and a nil error
// does not signify that the compression succeeded (since it is most likely still running)
// That means that the call that returns an error may not be the call that caused it.
// Only Flush and Close functions are guaranteed to return any errors up to that point.
func (z *Writer) Write(p []byte) (int, error) {
if err := z.checkError(); err != nil {
return 0, err
}
// Write the GZIP header lazily.
if !z.wroteHeader {
z.wroteHeader = true
z.buf[0] = gzipID1
z.buf[1] = gzipID2
z.buf[2] = gzipDeflate
z.buf[3] = 0
if z.Extra != nil {
z.buf[3] |= 0x04
}
if z.Name != "" {
z.buf[3] |= 0x08
}
if z.Comment != "" {
z.buf[3] |= 0x10
}
put4(z.buf[4:8], uint32(z.ModTime.Unix()))
if z.level == BestCompression {
z.buf[8] = 2
} else if z.level == BestSpeed {
z.buf[8] = 4
} else {
z.buf[8] = 0
}
z.buf[9] = z.OS
var n int
var err error
n, err = z.w.Write(z.buf[0:10])
if err != nil {
z.pushError(err)
return n, err
}
if z.Extra != nil {
err = z.writeBytes(z.Extra)
if err != nil {
z.pushError(err)
return n, err
}
}
if z.Name != "" {
err = z.writeString(z.Name)
if err != nil {
z.pushError(err)
return n, err
}
}
if z.Comment != "" {
err = z.writeString(z.Comment)
if err != nil {
z.pushError(err)
return n, err
}
}
// Start receiving data from compressors
go func() {
listen := z.results
var failed bool
for {
r, ok := <-listen
// If closed, we are finished.
if !ok {
return
}
if failed {
close(r.notifyWritten)
continue
}
buf := <-r.result
n, err := z.w.Write(buf)
if err != nil {
z.pushError(err)
close(r.notifyWritten)
failed = true
continue
}
if n != len(buf) {
z.pushError(fmt.Errorf("gzip: short write %d should be %d", n, len(buf)))
failed = true
close(r.notifyWritten)
continue
}
z.dstPool.Put(buf)
close(r.notifyWritten)
}
}()
z.currentBuffer = z.dstPool.Get().([]byte)
z.currentBuffer = z.currentBuffer[:0]
}
q := p
for len(q) > 0 {
length := len(q)
if length+len(z.currentBuffer) > z.blockSize {
length = z.blockSize - len(z.currentBuffer)
}
z.digest.Write(q[:length])
z.currentBuffer = append(z.currentBuffer, q[:length]...)
if len(z.currentBuffer) > z.blockSize {
panic("z.currentBuffer too large (most likely due to concurrent Write race)")
}
if len(z.currentBuffer) == z.blockSize {
z.compressCurrent(false)
if err := z.checkError(); err != nil {
return len(p) - len(q), err
}
}
z.size += length
q = q[length:]
}
return len(p), z.checkError()
}
// Step 1: compresses buffer to buffer
// Step 2: send writer to channel
// Step 3: Close result channel to indicate we are done
func (z *Writer) compressBlock(p, prevTail []byte, r result, closed bool) {
defer func() {
close(r.result)
z.wg.Done()
}()
buf := z.dstPool.Get().([]byte) // Corresponding Put in .Write's result writer
dest := bytes.NewBuffer(buf[:0])
compressor := z.dictFlatePool.Get().(*flate.Writer) // Put below
compressor.ResetDict(dest, prevTail)
compressor.Write(p)
z.dstPool.Put(p) // Corresponding Get in .Write and .compressCurrent
err := compressor.Flush()
if err != nil {
z.pushError(err)
return
}
if closed {
err = compressor.Close()
if err != nil {
z.pushError(err)
return
}
}
z.dictFlatePool.Put(compressor) // Get above
if prevTail != nil {
z.dstPool.Put(prevTail) // Get in .compressCurrent
}
// Read back buffer
buf = dest.Bytes()
r.result <- buf
}
// Flush flushes any pending compressed data to the underlying writer.
//
// It is useful mainly in compressed network protocols, to ensure that
// a remote reader has enough data to reconstruct a packet. Flush does
// not return until the data has been written. If the underlying
// writer returns an error, Flush returns that error.
//
// In the terminology of the zlib library, Flush is equivalent to Z_SYNC_FLUSH.
func (z *Writer) Flush() error {
if err := z.checkError(); err != nil {
return err
}
if z.closed {
return nil
}
if !z.wroteHeader {
_, err := z.Write(nil)
if err != nil {
return err
}
}
// We send current block to compression
z.compressCurrent(true)
return z.checkError()
}
// UncompressedSize will return the number of bytes written.
// pgzip only, not a function in the official gzip package.
func (z *Writer) UncompressedSize() int {
return z.size
}
// Close closes the Writer, flushing any unwritten data to the underlying
// io.Writer, but does not close the underlying io.Writer.
func (z *Writer) Close() error {
if err := z.checkError(); err != nil {
return err
}
if z.closed {
return nil
}
z.closed = true
if !z.wroteHeader {
z.Write(nil)
if err := z.checkError(); err != nil {
return err
}
}
z.compressCurrent(true)
if err := z.checkError(); err != nil {
return err
}
close(z.results)
put4(z.buf[0:4], z.digest.Sum32())
put4(z.buf[4:8], uint32(z.size))
_, err := z.w.Write(z.buf[0:8])
if err != nil {
z.pushError(err)
return err
}
return nil
}

4
src/cmd/linuxkit/vendor/modules.txt vendored
View File

@@ -327,11 +327,15 @@ github.com/hashicorp/go-version
github.com/jmespath/go-jmespath
# github.com/klauspost/compress v1.15.1
github.com/klauspost/compress
github.com/klauspost/compress/flate
github.com/klauspost/compress/fse
github.com/klauspost/compress/huff0
github.com/klauspost/compress/internal/snapref
github.com/klauspost/compress/zstd
github.com/klauspost/compress/zstd/internal/xxhash
# github.com/klauspost/pgzip v1.2.5
## explicit
github.com/klauspost/pgzip
# github.com/linuxkit/virtsock v0.0.0-20201010232012-f8cee7dfc7a3
github.com/linuxkit/virtsock/pkg/hvsock
github.com/linuxkit/virtsock/pkg/vsock