build(deps): bump github.com/containers/storage from 1.15.5 to 1.15.7

Bumps [github.com/containers/storage](https://github.com/containers/storage) from 1.15.5 to 1.15.7.
- [Release notes](https://github.com/containers/storage/releases)
- [Changelog](https://github.com/containers/storage/blob/master/docs/containers-storage-changes.md)
- [Commits](https://github.com/containers/storage/compare/v1.15.5...v1.15.7)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>
Signed-off-by: Matthew Heon <mheon@redhat.com>
This commit is contained in:
dependabot-preview[bot]
2020-01-23 08:41:51 +00:00
committed by Matthew Heon
parent ac3a6b80b0
commit 587a25fd8a
24 changed files with 795 additions and 136 deletions

View File

@ -38,7 +38,7 @@ func (b *bitWriter) addBits16Clean(value uint16, bits uint8) {
b.nBits += bits
}
// addBits16Clean will add up to 16 bits. value may not contain more set bits than indicated.
// encSymbol will add up to 16 bits. value may not contain more set bits than indicated.
// It will not check if there is space for them, so the caller must ensure that it has flushed recently.
func (b *bitWriter) encSymbol(ct cTable, symbol byte) {
enc := ct[symbol]
@ -46,6 +46,17 @@ func (b *bitWriter) encSymbol(ct cTable, symbol byte) {
b.nBits += enc.nBits
}
// encTwoSymbols will add up to 32 bits. value may not contain more set bits than indicated.
// It will not check if there is space for them, so the caller must ensure that it has flushed recently.
func (b *bitWriter) encTwoSymbols(ct cTable, av, bv byte) {
encA := ct[av]
encB := ct[bv]
sh := b.nBits & 63
combined := uint64(encA.val) | (uint64(encB.val) << (encA.nBits & 63))
b.bitContainer |= combined << sh
b.nBits += encA.nBits + encB.nBits
}
// addBits16ZeroNC will add up to 16 bits.
// It will not check if there is space for them,
// so the caller must ensure that it has flushed recently.

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@ -80,9 +80,12 @@ func compress(in []byte, s *Scratch, compressor func(src []byte) ([]byte, error)
if s.Reuse == ReusePolicyPrefer && canReuse {
keepTable := s.cTable
keepTL := s.actualTableLog
s.cTable = s.prevTable
s.actualTableLog = s.prevTableLog
s.Out, err = compressor(in)
s.cTable = keepTable
s.actualTableLog = keepTL
if err == nil && len(s.Out) < wantSize {
s.OutData = s.Out
return s.Out, true, nil
@ -92,7 +95,6 @@ func compress(in []byte, s *Scratch, compressor func(src []byte) ([]byte, error)
}
// Calculate new table.
s.optimalTableLog()
err = s.buildCTable()
if err != nil {
return nil, false, err
@ -109,9 +111,15 @@ func compress(in []byte, s *Scratch, compressor func(src []byte) ([]byte, error)
if oldSize <= hSize+newSize || hSize+12 >= wantSize {
// Retain cTable even if we re-use.
keepTable := s.cTable
keepTL := s.actualTableLog
s.cTable = s.prevTable
s.actualTableLog = s.prevTableLog
s.Out, err = compressor(in)
// Restore ctable.
s.cTable = keepTable
s.actualTableLog = keepTL
if err != nil {
return nil, false, err
}
@ -142,7 +150,7 @@ func compress(in []byte, s *Scratch, compressor func(src []byte) ([]byte, error)
return nil, false, ErrIncompressible
}
// Move current table into previous.
s.prevTable, s.cTable = s.cTable, s.prevTable[:0]
s.prevTable, s.prevTableLog, s.cTable = s.cTable, s.actualTableLog, s.prevTable[:0]
s.OutData = s.Out[len(s.OutTable):]
return s.Out, false, nil
}
@ -163,28 +171,23 @@ func (s *Scratch) compress1xDo(dst, src []byte) ([]byte, error) {
for i := len(src) & 3; i > 0; i-- {
bw.encSymbol(cTable, src[n+i-1])
}
n -= 4
if s.actualTableLog <= 8 {
n -= 4
for ; n >= 0; n -= 4 {
tmp := src[n : n+4]
// tmp should be len 4
bw.flush32()
bw.encSymbol(cTable, tmp[3])
bw.encSymbol(cTable, tmp[2])
bw.encSymbol(cTable, tmp[1])
bw.encSymbol(cTable, tmp[0])
bw.encTwoSymbols(cTable, tmp[3], tmp[2])
bw.encTwoSymbols(cTable, tmp[1], tmp[0])
}
} else {
n -= 4
for ; n >= 0; n -= 4 {
tmp := src[n : n+4]
// tmp should be len 4
bw.flush32()
bw.encSymbol(cTable, tmp[3])
bw.encSymbol(cTable, tmp[2])
bw.encTwoSymbols(cTable, tmp[3], tmp[2])
bw.flush32()
bw.encSymbol(cTable, tmp[1])
bw.encSymbol(cTable, tmp[0])
bw.encTwoSymbols(cTable, tmp[1], tmp[0])
}
}
err := bw.close()
@ -322,9 +325,26 @@ func (s *Scratch) canUseTable(c cTable) bool {
return true
}
func (s *Scratch) validateTable(c cTable) bool {
if len(c) < int(s.symbolLen) {
return false
}
for i, v := range s.count[:s.symbolLen] {
if v != 0 {
if c[i].nBits == 0 {
return false
}
if c[i].nBits > s.actualTableLog {
return false
}
}
}
return true
}
// minTableLog provides the minimum logSize to safely represent a distribution.
func (s *Scratch) minTableLog() uint8 {
minBitsSrc := highBit32(uint32(s.br.remain()-1)) + 1
minBitsSrc := highBit32(uint32(s.br.remain())) + 1
minBitsSymbols := highBit32(uint32(s.symbolLen-1)) + 2
if minBitsSrc < minBitsSymbols {
return uint8(minBitsSrc)
@ -336,7 +356,7 @@ func (s *Scratch) minTableLog() uint8 {
func (s *Scratch) optimalTableLog() {
tableLog := s.TableLog
minBits := s.minTableLog()
maxBitsSrc := uint8(highBit32(uint32(s.br.remain()-1))) - 2
maxBitsSrc := uint8(highBit32(uint32(s.br.remain()-1))) - 1
if maxBitsSrc < tableLog {
// Accuracy can be reduced
tableLog = maxBitsSrc
@ -363,6 +383,7 @@ type cTableEntry struct {
const huffNodesMask = huffNodesLen - 1
func (s *Scratch) buildCTable() error {
s.optimalTableLog()
s.huffSort()
if cap(s.cTable) < maxSymbolValue+1 {
s.cTable = make([]cTableEntry, s.symbolLen, maxSymbolValue+1)
@ -439,7 +460,7 @@ func (s *Scratch) buildCTable() error {
return fmt.Errorf("internal error: maxNbBits (%d) > tableLogMax (%d)", maxNbBits, tableLogMax)
}
var nbPerRank [tableLogMax + 1]uint16
var valPerRank [tableLogMax + 1]uint16
var valPerRank [16]uint16
for _, v := range huffNode[:nonNullRank+1] {
nbPerRank[v.nbBits]++
}
@ -455,16 +476,17 @@ func (s *Scratch) buildCTable() error {
}
// push nbBits per symbol, symbol order
// TODO: changed `s.symbolLen` -> `nonNullRank+1` (micro-opt)
for _, v := range huffNode[:nonNullRank+1] {
s.cTable[v.symbol].nBits = v.nbBits
}
// assign value within rank, symbol order
for n, val := range s.cTable[:s.symbolLen] {
v := valPerRank[val.nBits]
s.cTable[n].val = v
valPerRank[val.nBits] = v + 1
t := s.cTable[:s.symbolLen]
for n, val := range t {
nbits := val.nBits & 15
v := valPerRank[nbits]
t[n].val = v
valPerRank[nbits] = v + 1
}
return nil
@ -488,10 +510,12 @@ func (s *Scratch) huffSort() {
r := highBit32(v+1) & 31
rank[r].base++
}
for n := 30; n > 0; n-- {
// maxBitLength is log2(BlockSizeMax) + 1
const maxBitLength = 18 + 1
for n := maxBitLength; n > 0; n-- {
rank[n-1].base += rank[n].base
}
for n := range rank[:] {
for n := range rank[:maxBitLength] {
rank[n].current = rank[n].base
}
for n, c := range s.count[:s.symbolLen] {
@ -510,7 +534,7 @@ func (s *Scratch) huffSort() {
}
func (s *Scratch) setMaxHeight(lastNonNull int) uint8 {
maxNbBits := s.TableLog
maxNbBits := s.actualTableLog
huffNode := s.nodes[1 : huffNodesLen+1]
//huffNode = huffNode[: huffNodesLen]

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@ -83,7 +83,7 @@ type Scratch struct {
MaxSymbolValue uint8
// TableLog will attempt to override the tablelog for the next block.
// Must be <= 11.
// Must be <= 11 and >= 5.
TableLog uint8
// Reuse will specify the reuse policy
@ -105,6 +105,7 @@ type Scratch struct {
maxCount int // count of the most probable symbol
clearCount bool // clear count
actualTableLog uint8 // Selected tablelog.
prevTableLog uint8 // Tablelog for previous table
prevTable cTable // Table used for previous compression.
cTable cTable // compression table
dt dTable // decompression table
@ -127,8 +128,8 @@ func (s *Scratch) prepare(in []byte) (*Scratch, error) {
if s.TableLog == 0 {
s.TableLog = tableLogDefault
}
if s.TableLog > tableLogMax {
return nil, fmt.Errorf("tableLog (%d) > maxTableLog (%d)", s.TableLog, tableLogMax)
if s.TableLog > tableLogMax || s.TableLog < minTablelog {
return nil, fmt.Errorf(" invalid tableLog %d (%d -> %d)", s.TableLog, minTablelog, tableLogMax)
}
if s.MaxDecodedSize <= 0 || s.MaxDecodedSize > BlockSizeMax {
s.MaxDecodedSize = BlockSizeMax

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@ -36,7 +36,7 @@ so as always, testing is recommended.
For now, a high speed (fastest) and medium-fast (default) compressor has been implemented.
The "Fastest" compression ratio is roughly equivalent to zstd level 1.
The "Default" compression ration is roughly equivalent to zstd level 3 (default).
The "Default" compression ratio is roughly equivalent to zstd level 3 (default).
In terms of speed, it is typically 2x as fast as the stdlib deflate/gzip in its fastest mode.
The compression ratio compared to stdlib is around level 3, but usually 3x as fast.
@ -390,4 +390,4 @@ For sending files for reproducing errors use a service like [goobox](https://goo
For general feedback and experience reports, feel free to open an issue or write me on [Twitter](https://twitter.com/sh0dan).
This package includes the excellent [`github.com/cespare/xxhash`](https://github.com/cespare/xxhash) package Copyright (c) 2016 Caleb Spare.
This package includes the excellent [`github.com/cespare/xxhash`](https://github.com/cespare/xxhash) package Copyright (c) 2016 Caleb Spare.

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@ -299,6 +299,20 @@ func (b *blockEnc) encodeRaw(a []byte) {
}
}
// encodeRaw can be used to set the output to a raw representation of supplied bytes.
func (b *blockEnc) encodeRawTo(dst, src []byte) []byte {
var bh blockHeader
bh.setLast(b.last)
bh.setSize(uint32(len(src)))
bh.setType(blockTypeRaw)
dst = bh.appendTo(dst)
dst = append(dst, src...)
if debug {
println("Adding RAW block, length", len(src))
}
return dst
}
// encodeLits can be used if the block is only litLen.
func (b *blockEnc) encodeLits(raw bool) error {
var bh blockHeader
@ -324,18 +338,10 @@ func (b *blockEnc) encodeLits(raw bool) error {
if len(b.literals) >= 1024 {
// Use 4 Streams.
out, reUsed, err = huff0.Compress4X(b.literals, b.litEnc)
if len(out) > len(b.literals)-len(b.literals)>>4 {
// Bail out of compression is too little.
err = huff0.ErrIncompressible
}
} else if len(b.literals) > 32 {
// Use 1 stream
single = true
out, reUsed, err = huff0.Compress1X(b.literals, b.litEnc)
if len(out) > len(b.literals)-len(b.literals)>>4 {
// Bail out of compression is too little.
err = huff0.ErrIncompressible
}
} else {
err = huff0.ErrIncompressible
}
@ -437,7 +443,7 @@ func fuzzFseEncoder(data []byte) int {
return 1
}
// encode will encode the block and put the output in b.output.
// encode will encode the block and append the output in b.output.
func (b *blockEnc) encode(raw bool) error {
if len(b.sequences) == 0 {
return b.encodeLits(raw)
@ -451,6 +457,8 @@ func (b *blockEnc) encode(raw bool) error {
var lh literalsHeader
bh.setLast(b.last)
bh.setType(blockTypeCompressed)
// Store offset of the block header. Needed when we know the size.
bhOffset := len(b.output)
b.output = bh.appendTo(b.output)
var (
@ -468,6 +476,7 @@ func (b *blockEnc) encode(raw bool) error {
} else {
err = huff0.ErrIncompressible
}
switch err {
case huff0.ErrIncompressible:
lh.setType(literalsBlockRaw)
@ -735,18 +744,18 @@ func (b *blockEnc) encode(raw bool) error {
}
b.output = wr.out
if len(b.output)-3 >= b.size {
if len(b.output)-3-bhOffset >= b.size {
// Maybe even add a bigger margin.
b.litEnc.Reuse = huff0.ReusePolicyNone
return errIncompressible
}
// Size is output minus block header.
bh.setSize(uint32(len(b.output)) - 3)
bh.setSize(uint32(len(b.output)-bhOffset) - 3)
if debug {
println("Rewriting block header", bh)
}
_ = bh.appendTo(b.output[:0])
_ = bh.appendTo(b.output[bhOffset:bhOffset])
b.coders.setPrev(llEnc, mlEnc, ofEnc)
return nil
}

View File

@ -388,6 +388,35 @@ func (d *Decoder) Close() {
d.current.err = ErrDecoderClosed
}
// IOReadCloser returns the decoder as an io.ReadCloser for convenience.
// Any changes to the decoder will be reflected, so the returned ReadCloser
// can be reused along with the decoder.
// io.WriterTo is also supported by the returned ReadCloser.
func (d *Decoder) IOReadCloser() io.ReadCloser {
return closeWrapper{d: d}
}
// closeWrapper wraps a function call as a closer.
type closeWrapper struct {
d *Decoder
}
// WriteTo forwards WriteTo calls to the decoder.
func (c closeWrapper) WriteTo(w io.Writer) (n int64, err error) {
return c.d.WriteTo(w)
}
// Read forwards read calls to the decoder.
func (c closeWrapper) Read(p []byte) (n int, err error) {
return c.d.Read(p)
}
// Close closes the decoder.
func (c closeWrapper) Close() error {
c.d.Close()
return nil
}
type decodeOutput struct {
d *blockDec
b []byte

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@ -411,3 +411,316 @@ encodeLoop:
println("returning, recent offsets:", blk.recentOffsets, "extra literals:", blk.extraLits)
}
}
// EncodeNoHist will encode a block with no history and no following blocks.
// Most notable difference is that src will not be copied for history and
// we do not need to check for max match length.
func (e *doubleFastEncoder) EncodeNoHist(blk *blockEnc, src []byte) {
const (
// Input margin is the number of bytes we read (8)
// and the maximum we will read ahead (2)
inputMargin = 8 + 2
minNonLiteralBlockSize = 16
)
// Protect against e.cur wraparound.
if e.cur > (1<<30)+e.maxMatchOff {
for i := range e.table[:] {
e.table[i] = tableEntry{}
}
for i := range e.longTable[:] {
e.longTable[i] = tableEntry{}
}
e.cur = e.maxMatchOff
}
s := int32(0)
blk.size = len(src)
if len(src) < minNonLiteralBlockSize {
blk.extraLits = len(src)
blk.literals = blk.literals[:len(src)]
copy(blk.literals, src)
return
}
// Override src
sLimit := int32(len(src)) - inputMargin
// stepSize is the number of bytes to skip on every main loop iteration.
// It should be >= 1.
stepSize := int32(e.o.targetLength)
if stepSize == 0 {
stepSize++
}
const kSearchStrength = 8
// nextEmit is where in src the next emitLiteral should start from.
nextEmit := s
cv := load6432(src, s)
// Relative offsets
offset1 := int32(blk.recentOffsets[0])
offset2 := int32(blk.recentOffsets[1])
addLiterals := func(s *seq, until int32) {
if until == nextEmit {
return
}
blk.literals = append(blk.literals, src[nextEmit:until]...)
s.litLen = uint32(until - nextEmit)
}
if debug {
println("recent offsets:", blk.recentOffsets)
}
encodeLoop:
for {
var t int32
for {
nextHashS := hash5(cv, dFastShortTableBits)
nextHashL := hash8(cv, dFastLongTableBits)
candidateL := e.longTable[nextHashL]
candidateS := e.table[nextHashS]
const repOff = 1
repIndex := s - offset1 + repOff
entry := tableEntry{offset: s + e.cur, val: uint32(cv)}
e.longTable[nextHashL] = entry
e.table[nextHashS] = entry
if len(blk.sequences) > 2 {
if load3232(src, repIndex) == uint32(cv>>(repOff*8)) {
// Consider history as well.
var seq seq
//length := 4 + e.matchlen(s+4+repOff, repIndex+4, src)
length := 4 + int32(matchLen(src[s+4+repOff:], src[repIndex+4:]))
seq.matchLen = uint32(length - zstdMinMatch)
// We might be able to match backwards.
// Extend as long as we can.
start := s + repOff
// We end the search early, so we don't risk 0 literals
// and have to do special offset treatment.
startLimit := nextEmit + 1
tMin := s - e.maxMatchOff
if tMin < 0 {
tMin = 0
}
for repIndex > tMin && start > startLimit && src[repIndex-1] == src[start-1] {
repIndex--
start--
seq.matchLen++
}
addLiterals(&seq, start)
// rep 0
seq.offset = 1
if debugSequences {
println("repeat sequence", seq, "next s:", s)
}
blk.sequences = append(blk.sequences, seq)
s += length + repOff
nextEmit = s
if s >= sLimit {
if debug {
println("repeat ended", s, length)
}
break encodeLoop
}
cv = load6432(src, s)
continue
}
}
// Find the offsets of our two matches.
coffsetL := s - (candidateL.offset - e.cur)
coffsetS := s - (candidateS.offset - e.cur)
// Check if we have a long match.
if coffsetL < e.maxMatchOff && uint32(cv) == candidateL.val {
// Found a long match, likely at least 8 bytes.
// Reference encoder checks all 8 bytes, we only check 4,
// but the likelihood of both the first 4 bytes and the hash matching should be enough.
t = candidateL.offset - e.cur
if debug && s <= t {
panic("s <= t")
}
if debug && s-t > e.maxMatchOff {
panic("s - t >e.maxMatchOff")
}
if debugMatches {
println("long match")
}
break
}
// Check if we have a short match.
if coffsetS < e.maxMatchOff && uint32(cv) == candidateS.val {
// found a regular match
// See if we can find a long match at s+1
const checkAt = 1
cv := load6432(src, s+checkAt)
nextHashL = hash8(cv, dFastLongTableBits)
candidateL = e.longTable[nextHashL]
coffsetL = s - (candidateL.offset - e.cur) + checkAt
// We can store it, since we have at least a 4 byte match.
e.longTable[nextHashL] = tableEntry{offset: s + checkAt + e.cur, val: uint32(cv)}
if coffsetL < e.maxMatchOff && uint32(cv) == candidateL.val {
// Found a long match, likely at least 8 bytes.
// Reference encoder checks all 8 bytes, we only check 4,
// but the likelihood of both the first 4 bytes and the hash matching should be enough.
t = candidateL.offset - e.cur
s += checkAt
if debugMatches {
println("long match (after short)")
}
break
}
t = candidateS.offset - e.cur
if debug && s <= t {
panic("s <= t")
}
if debug && s-t > e.maxMatchOff {
panic("s - t >e.maxMatchOff")
}
if debug && t < 0 {
panic("t<0")
}
if debugMatches {
println("short match")
}
break
}
// No match found, move forward in input.
s += stepSize + ((s - nextEmit) >> (kSearchStrength - 1))
if s >= sLimit {
break encodeLoop
}
cv = load6432(src, s)
}
// A 4-byte match has been found. Update recent offsets.
// We'll later see if more than 4 bytes.
offset2 = offset1
offset1 = s - t
if debug && s <= t {
panic("s <= t")
}
// Extend the 4-byte match as long as possible.
//l := e.matchlen(s+4, t+4, src) + 4
l := int32(matchLen(src[s+4:], src[t+4:])) + 4
// Extend backwards
tMin := s - e.maxMatchOff
if tMin < 0 {
tMin = 0
}
for t > tMin && s > nextEmit && src[t-1] == src[s-1] {
s--
t--
l++
}
// Write our sequence
var seq seq
seq.litLen = uint32(s - nextEmit)
seq.matchLen = uint32(l - zstdMinMatch)
if seq.litLen > 0 {
blk.literals = append(blk.literals, src[nextEmit:s]...)
}
seq.offset = uint32(s-t) + 3
s += l
if debugSequences {
println("sequence", seq, "next s:", s)
}
blk.sequences = append(blk.sequences, seq)
nextEmit = s
if s >= sLimit {
break encodeLoop
}
// Index match start+1 (long) and start+2 (short)
index0 := s - l + 1
// Index match end-2 (long) and end-1 (short)
index1 := s - 2
cv0 := load6432(src, index0)
cv1 := load6432(src, index1)
te0 := tableEntry{offset: index0 + e.cur, val: uint32(cv0)}
te1 := tableEntry{offset: index1 + e.cur, val: uint32(cv1)}
e.longTable[hash8(cv0, dFastLongTableBits)] = te0
e.longTable[hash8(cv1, dFastLongTableBits)] = te1
cv0 >>= 8
cv1 >>= 8
te0.offset++
te1.offset++
te0.val = uint32(cv0)
te1.val = uint32(cv1)
e.table[hash5(cv0, dFastShortTableBits)] = te0
e.table[hash5(cv1, dFastShortTableBits)] = te1
cv = load6432(src, s)
if len(blk.sequences) <= 2 {
continue
}
// Check offset 2
for {
o2 := s - offset2
if load3232(src, o2) != uint32(cv) {
// Do regular search
break
}
// Store this, since we have it.
nextHashS := hash5(cv1>>8, dFastShortTableBits)
nextHashL := hash8(cv, dFastLongTableBits)
// We have at least 4 byte match.
// No need to check backwards. We come straight from a match
//l := 4 + e.matchlen(s+4, o2+4, src)
l := 4 + int32(matchLen(src[s+4:], src[o2+4:]))
entry := tableEntry{offset: s + e.cur, val: uint32(cv)}
e.longTable[nextHashL] = entry
e.table[nextHashS] = entry
seq.matchLen = uint32(l) - zstdMinMatch
seq.litLen = 0
// Since litlen is always 0, this is offset 1.
seq.offset = 1
s += l
nextEmit = s
if debugSequences {
println("sequence", seq, "next s:", s)
}
blk.sequences = append(blk.sequences, seq)
// Swap offset 1 and 2.
offset1, offset2 = offset2, offset1
if s >= sLimit {
// Finished
break encodeLoop
}
cv = load6432(src, s)
}
}
if int(nextEmit) < len(src) {
blk.literals = append(blk.literals, src[nextEmit:]...)
blk.extraLits = len(src) - int(nextEmit)
}
if debug {
println("returning, recent offsets:", blk.recentOffsets, "extra literals:", blk.extraLits)
}
}

View File

@ -329,6 +329,246 @@ encodeLoop:
}
}
// EncodeNoHist will encode a block with no history and no following blocks.
// Most notable difference is that src will not be copied for history and
// we do not need to check for max match length.
func (e *fastEncoder) EncodeNoHist(blk *blockEnc, src []byte) {
const (
inputMargin = 8
minNonLiteralBlockSize = 1 + 1 + inputMargin
)
if debug {
if len(src) > maxBlockSize {
panic("src too big")
}
}
// Protect against e.cur wraparound.
if e.cur > (1<<30)+e.maxMatchOff {
for i := range e.table[:] {
e.table[i] = tableEntry{}
}
e.cur = e.maxMatchOff
}
s := int32(0)
blk.size = len(src)
if len(src) < minNonLiteralBlockSize {
blk.extraLits = len(src)
blk.literals = blk.literals[:len(src)]
copy(blk.literals, src)
return
}
sLimit := int32(len(src)) - inputMargin
// stepSize is the number of bytes to skip on every main loop iteration.
// It should be >= 2.
const stepSize = 2
// TEMPLATE
const hashLog = tableBits
// seems global, but would be nice to tweak.
const kSearchStrength = 8
// nextEmit is where in src the next emitLiteral should start from.
nextEmit := s
cv := load6432(src, s)
// Relative offsets
offset1 := int32(blk.recentOffsets[0])
offset2 := int32(blk.recentOffsets[1])
addLiterals := func(s *seq, until int32) {
if until == nextEmit {
return
}
blk.literals = append(blk.literals, src[nextEmit:until]...)
s.litLen = uint32(until - nextEmit)
}
if debug {
println("recent offsets:", blk.recentOffsets)
}
encodeLoop:
for {
// t will contain the match offset when we find one.
// When existing the search loop, we have already checked 4 bytes.
var t int32
// We will not use repeat offsets across blocks.
// By not using them for the first 3 matches
for {
nextHash := hash6(cv, hashLog)
nextHash2 := hash6(cv>>8, hashLog)
candidate := e.table[nextHash]
candidate2 := e.table[nextHash2]
repIndex := s - offset1 + 2
e.table[nextHash] = tableEntry{offset: s + e.cur, val: uint32(cv)}
e.table[nextHash2] = tableEntry{offset: s + e.cur + 1, val: uint32(cv >> 8)}
if len(blk.sequences) > 2 && load3232(src, repIndex) == uint32(cv>>16) {
// Consider history as well.
var seq seq
// lenght := 4 + e.matchlen(s+6, repIndex+4, src)
lenght := 4 + int32(matchLen(src[s+6:], src[repIndex+4:]))
seq.matchLen = uint32(lenght - zstdMinMatch)
// We might be able to match backwards.
// Extend as long as we can.
start := s + 2
// We end the search early, so we don't risk 0 literals
// and have to do special offset treatment.
startLimit := nextEmit + 1
sMin := s - e.maxMatchOff
if sMin < 0 {
sMin = 0
}
for repIndex > sMin && start > startLimit && src[repIndex-1] == src[start-1] {
repIndex--
start--
seq.matchLen++
}
addLiterals(&seq, start)
// rep 0
seq.offset = 1
if debugSequences {
println("repeat sequence", seq, "next s:", s)
}
blk.sequences = append(blk.sequences, seq)
s += lenght + 2
nextEmit = s
if s >= sLimit {
if debug {
println("repeat ended", s, lenght)
}
break encodeLoop
}
cv = load6432(src, s)
continue
}
coffset0 := s - (candidate.offset - e.cur)
coffset1 := s - (candidate2.offset - e.cur) + 1
if coffset0 < e.maxMatchOff && uint32(cv) == candidate.val {
// found a regular match
t = candidate.offset - e.cur
if debug && s <= t {
panic("s <= t")
}
if debug && s-t > e.maxMatchOff {
panic("s - t >e.maxMatchOff")
}
break
}
if coffset1 < e.maxMatchOff && uint32(cv>>8) == candidate2.val {
// found a regular match
t = candidate2.offset - e.cur
s++
if debug && s <= t {
panic("s <= t")
}
if debug && s-t > e.maxMatchOff {
panic("s - t >e.maxMatchOff")
}
if debug && t < 0 {
panic("t<0")
}
break
}
s += stepSize + ((s - nextEmit) >> (kSearchStrength - 1))
if s >= sLimit {
break encodeLoop
}
cv = load6432(src, s)
}
// A 4-byte match has been found. We'll later see if more than 4 bytes.
offset2 = offset1
offset1 = s - t
if debug && s <= t {
panic("s <= t")
}
// Extend the 4-byte match as long as possible.
//l := e.matchlenNoHist(s+4, t+4, src) + 4
l := int32(matchLen(src[s+4:], src[t+4:])) + 4
// Extend backwards
tMin := s - e.maxMatchOff
if tMin < 0 {
tMin = 0
}
for t > tMin && s > nextEmit && src[t-1] == src[s-1] {
s--
t--
l++
}
// Write our sequence.
var seq seq
seq.litLen = uint32(s - nextEmit)
seq.matchLen = uint32(l - zstdMinMatch)
if seq.litLen > 0 {
blk.literals = append(blk.literals, src[nextEmit:s]...)
}
// Don't use repeat offsets
seq.offset = uint32(s-t) + 3
s += l
if debugSequences {
println("sequence", seq, "next s:", s)
}
blk.sequences = append(blk.sequences, seq)
nextEmit = s
if s >= sLimit {
break encodeLoop
}
cv = load6432(src, s)
// Check offset 2
if o2 := s - offset2; len(blk.sequences) > 2 && load3232(src, o2) == uint32(cv) {
// We have at least 4 byte match.
// No need to check backwards. We come straight from a match
//l := 4 + e.matchlenNoHist(s+4, o2+4, src)
l := 4 + int32(matchLen(src[s+4:], src[o2+4:]))
// Store this, since we have it.
nextHash := hash6(cv, hashLog)
e.table[nextHash] = tableEntry{offset: s + e.cur, val: uint32(cv)}
seq.matchLen = uint32(l) - zstdMinMatch
seq.litLen = 0
// Since litlen is always 0, this is offset 1.
seq.offset = 1
s += l
nextEmit = s
if debugSequences {
println("sequence", seq, "next s:", s)
}
blk.sequences = append(blk.sequences, seq)
// Swap offset 1 and 2.
offset1, offset2 = offset2, offset1
if s >= sLimit {
break encodeLoop
}
// Prepare next loop.
cv = load6432(src, s)
}
}
if int(nextEmit) < len(src) {
blk.literals = append(blk.literals, src[nextEmit:]...)
blk.extraLits = len(src) - int(nextEmit)
}
if debug {
println("returning, recent offsets:", blk.recentOffsets, "extra literals:", blk.extraLits)
}
}
func (e *fastEncoder) addBlock(src []byte) int32 {
// check if we have space already
if len(e.hist)+len(src) > cap(e.hist) {
@ -362,6 +602,11 @@ func (e *fastEncoder) UseBlock(enc *blockEnc) {
e.blk = enc
}
func (e *fastEncoder) matchlenNoHist(s, t int32, src []byte) int32 {
// Extend the match to be as long as possible.
return int32(matchLen(src[s:], src[t:]))
}
func (e *fastEncoder) matchlen(s, t int32, src []byte) int32 {
if debug {
if s < 0 {

View File

@ -29,6 +29,7 @@ type Encoder struct {
type encoder interface {
Encode(blk *blockEnc, src []byte)
EncodeNoHist(blk *blockEnc, src []byte)
Block() *blockEnc
CRC() *xxhash.Digest
AppendCRC([]byte) []byte
@ -433,7 +434,8 @@ func (e *Encoder) EncodeAll(src, dst []byte) []byte {
}()
enc.Reset()
blk := enc.Block()
single := len(src) > 1<<20
// Use single segments when above minimum window and below 1MB.
single := len(src) < 1<<20 && len(src) > MinWindowSize
if e.o.single != nil {
single = *e.o.single
}
@ -454,25 +456,22 @@ func (e *Encoder) EncodeAll(src, dst []byte) []byte {
panic(err)
}
for len(src) > 0 {
todo := src
if len(todo) > e.o.blockSize {
todo = todo[:e.o.blockSize]
}
src = src[len(todo):]
if len(src) <= e.o.blockSize && len(src) <= maxBlockSize {
// Slightly faster with no history and everything in one block.
if e.o.crc {
_, _ = enc.CRC().Write(todo)
_, _ = enc.CRC().Write(src)
}
blk.reset(nil)
blk.pushOffsets()
enc.Encode(blk, todo)
if len(src) == 0 {
blk.last = true
}
err := errIncompressible
blk.last = true
enc.EncodeNoHist(blk, src)
// If we got the exact same number of literals as input,
// assume the literals cannot be compressed.
if len(blk.literals) != len(todo) || len(todo) != e.o.blockSize {
err := errIncompressible
oldout := blk.output
if len(blk.literals) != len(src) || len(src) != e.o.blockSize {
// Output directly to dst
blk.output = dst
err = blk.encode(e.o.noEntropy)
}
@ -481,13 +480,49 @@ func (e *Encoder) EncodeAll(src, dst []byte) []byte {
if debug {
println("Storing incompressible block as raw")
}
blk.encodeRaw(todo)
blk.popOffsets()
dst = blk.encodeRawTo(dst, src)
case nil:
dst = blk.output
default:
panic(err)
}
dst = append(dst, blk.output...)
blk.output = oldout
} else {
for len(src) > 0 {
todo := src
if len(todo) > e.o.blockSize {
todo = todo[:e.o.blockSize]
}
src = src[len(todo):]
if e.o.crc {
_, _ = enc.CRC().Write(todo)
}
blk.reset(nil)
blk.pushOffsets()
enc.Encode(blk, todo)
if len(src) == 0 {
blk.last = true
}
err := errIncompressible
// If we got the exact same number of literals as input,
// assume the literals cannot be compressed.
if len(blk.literals) != len(todo) || len(todo) != e.o.blockSize {
err = blk.encode(e.o.noEntropy)
}
switch err {
case errIncompressible:
if debug {
println("Storing incompressible block as raw")
}
dst = blk.encodeRawTo(dst, todo)
blk.popOffsets()
case nil:
dst = append(dst, blk.output...)
default:
panic(err)
}
}
}
if e.o.crc {
dst = enc.AppendCRC(dst)