[chore]: Bump github.com/minio/minio-go/v7 from 7.0.48 to 7.0.49 (#1567)

Bumps [github.com/minio/minio-go/v7](https://github.com/minio/minio-go) from 7.0.48 to 7.0.49.
- [Release notes](https://github.com/minio/minio-go/releases)
- [Commits](https://github.com/minio/minio-go/compare/v7.0.48...v7.0.49)

---
updated-dependencies:
- dependency-name: github.com/minio/minio-go/v7
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
This commit is contained in:
dependabot[bot]
2023-02-27 10:21:58 +01:00
committed by GitHub
parent e1b704e06e
commit 752c38b0d5
38 changed files with 1696 additions and 1023 deletions

View File

@ -131,7 +131,8 @@ 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])
//copy(d.window[:], d.window[windowSize:2*windowSize])
*(*[windowSize]byte)(d.window) = *(*[windowSize]byte)(d.window[windowSize:])
s.index -= windowSize
d.windowEnd -= windowSize
if d.blockStart >= windowSize {
@ -293,7 +294,6 @@ func (d *compressor) findMatch(pos int, prevHead int, lookahead int) (length, of
}
offset = 0
cGain := 0
if d.chain < 100 {
for i := prevHead; tries > 0; tries-- {
if wEnd == win[i+length] {
@ -321,10 +321,14 @@ func (d *compressor) findMatch(pos int, prevHead int, lookahead int) (length, of
return
}
// Minimum gain to accept a match.
cGain := 4
// Some like it higher (CSV), some like it lower (JSON)
const baseCost = 6
const baseCost = 3
// 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)
@ -332,7 +336,7 @@ func (d *compressor) findMatch(pos int, prevHead int, lookahead int) (length, of
// 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]))
//fmt.Println("gain:", newGain, "prev:", cGain, "raw:", d.h.bitLengthRaw(wPos[:n]), "this-len:", n, "prev-len:", length)
if newGain > cGain {
length = n
offset = pos - i
@ -373,6 +377,12 @@ func hash4(b []byte) uint32 {
return hash4u(binary.LittleEndian.Uint32(b), hashBits)
}
// 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)
}
// bulkHash4 will compute hashes using the same
// algorithm as hash4
func bulkHash4(b []byte, dst []uint32) {
@ -483,27 +493,103 @@ func (d *compressor) deflateLazy() {
}
if prevLength >= minMatchLength && s.length <= prevLength {
// Check for better match at end...
// No better match, but 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.
// Skip forward a number of bytes.
// Offset of 2 seems to yield best results. 3 is sometimes better.
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]) - 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
// Check all, except full length
if prevLength < maxMatchLength-checkOff {
prevIndex := s.index - 1
if prevIndex+prevLength < s.maxInsertIndex {
end := lookahead
if lookahead > maxMatchLength+checkOff {
end = maxMatchLength + checkOff
}
end += prevIndex
// Hash at match end.
h := hash4(d.window[prevIndex+prevLength:])
ch2 := int(s.hashHead[h]) - s.hashOffset - prevLength
if prevIndex-ch2 != prevOffset && ch2 > minIndex+checkOff {
length := matchLen(d.window[prevIndex+checkOff:end], d.window[ch2+checkOff:])
// It seems like a pure length metric is best.
if length > prevLength {
prevLength = length
prevOffset = prevIndex - ch2
// Extend back...
for i := checkOff - 1; i >= 0; i-- {
if prevLength >= maxMatchLength || d.window[prevIndex+i] != d.window[ch2+i] {
// Emit tokens we "owe"
for j := 0; j <= i; j++ {
d.tokens.AddLiteral(d.window[prevIndex+j])
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.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)
}
}
break
} else {
prevLength++
}
}
} else if false {
// Check one further ahead.
// Only rarely better, disabled for now.
prevIndex++
h := hash4(d.window[prevIndex+prevLength:])
ch2 := int(s.hashHead[h]) - s.hashOffset - prevLength
if prevIndex-ch2 != prevOffset && ch2 > minIndex+checkOff {
length := matchLen(d.window[prevIndex+checkOff:end], d.window[ch2+checkOff:])
// It seems like a pure length metric is best.
if length > prevLength+checkOff {
prevLength = length
prevOffset = prevIndex - ch2
prevIndex--
// Extend back...
for i := checkOff; i >= 0; i-- {
if prevLength >= maxMatchLength || d.window[prevIndex+i] != d.window[ch2+i-1] {
// Emit tokens we "owe"
for j := 0; j <= i; j++ {
d.tokens.AddLiteral(d.window[prevIndex+j])
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.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)
}
}
break
} else {
prevLength++
}
}
}
}
}
}
}
}

View File

@ -7,19 +7,19 @@ 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.
// - 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.
// - 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

View File

@ -58,17 +58,6 @@ const (
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:])
}
@ -77,10 +66,6 @@ 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
}
@ -104,7 +89,8 @@ func (e *fastGen) addBlock(src []byte) int32 {
}
// Move down
offset := int32(len(e.hist)) - maxMatchOffset
copy(e.hist[0:maxMatchOffset], e.hist[offset:])
// copy(e.hist[0:maxMatchOffset], e.hist[offset:])
*(*[maxMatchOffset]byte)(e.hist) = *(*[maxMatchOffset]byte)(e.hist[offset:])
e.cur += offset
e.hist = e.hist[:maxMatchOffset]
}
@ -114,39 +100,36 @@ func (e *fastGen) addBlock(src []byte) int32 {
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)
}
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))
// hashLen returns a hash of the lowest mls bytes of with length output bits.
// mls must be >=3 and <=8. Any other value will return hash for 4 bytes.
// length should always be < 32.
// Preferably length and mls should be a constant for inlining.
func hashLen(u uint64, length, mls uint8) uint32 {
switch mls {
case 3:
return (uint32(u<<8) * prime3bytes) >> (32 - length)
case 5:
return uint32(((u << (64 - 40)) * prime5bytes) >> (64 - length))
case 6:
return uint32(((u << (64 - 48)) * prime6bytes) >> (64 - length))
case 7:
return uint32(((u << (64 - 56)) * prime7bytes) >> (64 - length))
case 8:
return uint32((u * prime8bytes) >> (64 - length))
default:
return (uint32(u) * prime4bytes) >> (32 - length)
}
}
// matchlen will return the match length between offsets and t in src.

View File

@ -265,9 +265,9 @@ func (w *huffmanBitWriter) writeBytes(bytes []byte) {
// Codes 0-15 are single byte codes. Codes 16-18 are followed by additional
// information. Code badCode is an end marker
//
// numLiterals The number of literals in literalEncoding
// numOffsets The number of offsets in offsetEncoding
// litenc, offenc The literal and offset encoder to use
// numLiterals The number of literals in literalEncoding
// numOffsets The number of offsets in offsetEncoding
// litenc, offenc The literal and offset encoder to use
func (w *huffmanBitWriter) generateCodegen(numLiterals int, numOffsets int, litEnc, offEnc *huffmanEncoder) {
for i := range w.codegenFreq {
w.codegenFreq[i] = 0
@ -460,9 +460,9 @@ func (w *huffmanBitWriter) writeOutBits() {
// Write the header of a dynamic Huffman block to the output stream.
//
// numLiterals The number of literals specified in codegen
// numOffsets The number of offsets specified in codegen
// numCodegens The number of codegens used in codegen
// numLiterals The number of literals specified in codegen
// numOffsets The number of offsets specified in codegen
// numCodegens The number of codegens used in codegen
func (w *huffmanBitWriter) writeDynamicHeader(numLiterals int, numOffsets int, numCodegens int, isEof bool) {
if w.err != nil {
return
@ -790,9 +790,11 @@ func (w *huffmanBitWriter) fillTokens() {
// and offsetEncoding.
// The number of literal and offset tokens is returned.
func (w *huffmanBitWriter) indexTokens(t *tokens, filled bool) (numLiterals, numOffsets int) {
copy(w.literalFreq[:], t.litHist[:])
copy(w.literalFreq[256:], t.extraHist[:])
copy(w.offsetFreq[:], t.offHist[:offsetCodeCount])
//copy(w.literalFreq[:], t.litHist[:])
*(*[256]uint16)(w.literalFreq[:]) = t.litHist
//copy(w.literalFreq[256:], t.extraHist[:])
*(*[32]uint16)(w.literalFreq[256:]) = t.extraHist
w.offsetFreq = t.offHist
if t.n == 0 {
return

View File

@ -168,13 +168,18 @@ func (h *huffmanEncoder) canReuseBits(freq []uint16) int {
// 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
//
// 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.
//
// 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.
//
// that should be encoded in i bits.
func (h *huffmanEncoder) bitCounts(list []literalNode, maxBits int32) []int32 {
if maxBits >= maxBitsLimit {
panic("flate: maxBits too large")

View File

@ -19,6 +19,7 @@ func (e *fastEncL1) Encode(dst *tokens, src []byte) {
const (
inputMargin = 12 - 1
minNonLiteralBlockSize = 1 + 1 + inputMargin
hashBytes = 5
)
if debugDeflate && e.cur < 0 {
panic(fmt.Sprint("e.cur < 0: ", e.cur))
@ -68,7 +69,7 @@ func (e *fastEncL1) Encode(dst *tokens, src []byte) {
sLimit := int32(len(src) - inputMargin)
// nextEmit is where in src the next emitLiteral should start from.
cv := load3232(src, s)
cv := load6432(src, s)
for {
const skipLog = 5
@ -77,7 +78,7 @@ func (e *fastEncL1) Encode(dst *tokens, src []byte) {
nextS := s
var candidate tableEntry
for {
nextHash := hash(cv)
nextHash := hashLen(cv, tableBits, hashBytes)
candidate = e.table[nextHash]
nextS = s + doEvery + (s-nextEmit)>>skipLog
if nextS > sLimit {
@ -86,16 +87,16 @@ func (e *fastEncL1) Encode(dst *tokens, src []byte) {
now := load6432(src, nextS)
e.table[nextHash] = tableEntry{offset: s + e.cur}
nextHash = hash(uint32(now))
nextHash = hashLen(now, tableBits, hashBytes)
offset := s - (candidate.offset - e.cur)
if offset < maxMatchOffset && cv == load3232(src, candidate.offset-e.cur) {
if offset < maxMatchOffset && uint32(cv) == load3232(src, candidate.offset-e.cur) {
e.table[nextHash] = tableEntry{offset: nextS + e.cur}
break
}
// Do one right away...
cv = uint32(now)
cv = now
s = nextS
nextS++
candidate = e.table[nextHash]
@ -103,11 +104,11 @@ func (e *fastEncL1) Encode(dst *tokens, src []byte) {
e.table[nextHash] = tableEntry{offset: s + e.cur}
offset = s - (candidate.offset - e.cur)
if offset < maxMatchOffset && cv == load3232(src, candidate.offset-e.cur) {
if offset < maxMatchOffset && uint32(cv) == load3232(src, candidate.offset-e.cur) {
e.table[nextHash] = tableEntry{offset: nextS + e.cur}
break
}
cv = uint32(now)
cv = now
s = nextS
}
@ -198,9 +199,9 @@ func (e *fastEncL1) Encode(dst *tokens, src []byte) {
}
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}
if int(s+l+8) < len(src) {
cv := load6432(src, s)
e.table[hashLen(cv, tableBits, hashBytes)] = tableEntry{offset: s + e.cur}
}
goto emitRemainder
}
@ -213,16 +214,16 @@ func (e *fastEncL1) Encode(dst *tokens, src []byte) {
// three load32 calls.
x := load6432(src, s-2)
o := e.cur + s - 2
prevHash := hash(uint32(x))
prevHash := hashLen(x, tableBits, hashBytes)
e.table[prevHash] = tableEntry{offset: o}
x >>= 16
currHash := hash(uint32(x))
currHash := hashLen(x, tableBits, hashBytes)
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)
cv = x >> 8
s++
break
}

View File

@ -16,6 +16,7 @@ func (e *fastEncL2) Encode(dst *tokens, src []byte) {
const (
inputMargin = 12 - 1
minNonLiteralBlockSize = 1 + 1 + inputMargin
hashBytes = 5
)
if debugDeflate && e.cur < 0 {
@ -66,7 +67,7 @@ func (e *fastEncL2) Encode(dst *tokens, src []byte) {
sLimit := int32(len(src) - inputMargin)
// nextEmit is where in src the next emitLiteral should start from.
cv := load3232(src, s)
cv := load6432(src, s)
for {
// When should we start skipping if we haven't found matches in a long while.
const skipLog = 5
@ -75,7 +76,7 @@ func (e *fastEncL2) Encode(dst *tokens, src []byte) {
nextS := s
var candidate tableEntry
for {
nextHash := hash4u(cv, bTableBits)
nextHash := hashLen(cv, bTableBits, hashBytes)
s = nextS
nextS = s + doEvery + (s-nextEmit)>>skipLog
if nextS > sLimit {
@ -84,16 +85,16 @@ func (e *fastEncL2) Encode(dst *tokens, src []byte) {
candidate = e.table[nextHash]
now := load6432(src, nextS)
e.table[nextHash] = tableEntry{offset: s + e.cur}
nextHash = hash4u(uint32(now), bTableBits)
nextHash = hashLen(now, bTableBits, hashBytes)
offset := s - (candidate.offset - e.cur)
if offset < maxMatchOffset && cv == load3232(src, candidate.offset-e.cur) {
if offset < maxMatchOffset && uint32(cv) == load3232(src, candidate.offset-e.cur) {
e.table[nextHash] = tableEntry{offset: nextS + e.cur}
break
}
// Do one right away...
cv = uint32(now)
cv = now
s = nextS
nextS++
candidate = e.table[nextHash]
@ -101,10 +102,10 @@ func (e *fastEncL2) Encode(dst *tokens, src []byte) {
e.table[nextHash] = tableEntry{offset: s + e.cur}
offset = s - (candidate.offset - e.cur)
if offset < maxMatchOffset && cv == load3232(src, candidate.offset-e.cur) {
if offset < maxMatchOffset && uint32(cv) == load3232(src, candidate.offset-e.cur) {
break
}
cv = uint32(now)
cv = now
}
// A 4-byte match has been found. We'll later see if more than 4 bytes
@ -154,9 +155,9 @@ func (e *fastEncL2) Encode(dst *tokens, src []byte) {
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}
if int(s+l+8) < len(src) {
cv := load6432(src, s)
e.table[hashLen(cv, bTableBits, hashBytes)] = tableEntry{offset: s + e.cur}
}
goto emitRemainder
}
@ -164,15 +165,15 @@ func (e *fastEncL2) Encode(dst *tokens, src []byte) {
// 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)
nextHash := hashLen(x, bTableBits, hashBytes)
e.table[nextHash] = tableEntry{offset: e.cur + i}
// Skip one
x >>= 16
nextHash = hash4u(uint32(x), bTableBits)
nextHash = hashLen(x, bTableBits, hashBytes)
e.table[nextHash] = tableEntry{offset: e.cur + i + 2}
// Skip one
x >>= 16
nextHash = hash4u(uint32(x), bTableBits)
nextHash = hashLen(x, bTableBits, hashBytes)
e.table[nextHash] = tableEntry{offset: e.cur + i + 4}
}
@ -184,17 +185,17 @@ func (e *fastEncL2) Encode(dst *tokens, src []byte) {
// three load32 calls.
x := load6432(src, s-2)
o := e.cur + s - 2
prevHash := hash4u(uint32(x), bTableBits)
prevHash2 := hash4u(uint32(x>>8), bTableBits)
prevHash := hashLen(x, bTableBits, hashBytes)
prevHash2 := hashLen(x>>8, bTableBits, hashBytes)
e.table[prevHash] = tableEntry{offset: o}
e.table[prevHash2] = tableEntry{offset: o + 1}
currHash := hash4u(uint32(x>>16), bTableBits)
currHash := hashLen(x>>16, bTableBits, hashBytes)
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)
cv = x >> 24
s++
break
}

View File

@ -11,10 +11,11 @@ type fastEncL3 struct {
// 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
inputMargin = 12 - 1
minNonLiteralBlockSize = 1 + 1 + inputMargin
tableBits = 16
tableSize = 1 << tableBits
hashBytes = 5
)
if debugDeflate && e.cur < 0 {
@ -69,20 +70,20 @@ func (e *fastEncL3) Encode(dst *tokens, src []byte) {
sLimit := int32(len(src) - inputMargin)
// nextEmit is where in src the next emitLiteral should start from.
cv := load3232(src, s)
cv := load6432(src, s)
for {
const skipLog = 6
const skipLog = 7
nextS := s
var candidate tableEntry
for {
nextHash := hash4u(cv, tableBits)
nextHash := hashLen(cv, tableBits, hashBytes)
s = nextS
nextS = s + 1 + (s-nextEmit)>>skipLog
if nextS > sLimit {
goto emitRemainder
}
candidates := e.table[nextHash]
now := load3232(src, nextS)
now := load6432(src, nextS)
// Safe offset distance until s + 4...
minOffset := e.cur + s - (maxMatchOffset - 4)
@ -96,8 +97,8 @@ func (e *fastEncL3) Encode(dst *tokens, src []byte) {
continue
}
if cv == load3232(src, candidate.offset-e.cur) {
if candidates.Prev.offset < minOffset || cv != load3232(src, candidates.Prev.offset-e.cur) {
if uint32(cv) == load3232(src, candidate.offset-e.cur) {
if candidates.Prev.offset < minOffset || uint32(cv) != load3232(src, candidates.Prev.offset-e.cur) {
break
}
// Both match and are valid, pick longest.
@ -112,7 +113,7 @@ func (e *fastEncL3) Encode(dst *tokens, src []byte) {
// 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) {
if candidate.offset > minOffset && uint32(cv) == load3232(src, candidate.offset-e.cur) {
break
}
}
@ -164,9 +165,9 @@ func (e *fastEncL3) Encode(dst *tokens, src []byte) {
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)
if int(t+8) < len(src) && t > 0 {
cv = load6432(src, t)
nextHash := hashLen(cv, tableBits, hashBytes)
e.table[nextHash] = tableEntryPrev{
Prev: e.table[nextHash].Cur,
Cur: tableEntry{offset: e.cur + t},
@ -176,8 +177,8 @@ func (e *fastEncL3) Encode(dst *tokens, src []byte) {
}
// Store every 5th hash in-between.
for i := s - l + 2; i < s-5; i += 5 {
nextHash := hash4u(load3232(src, i), tableBits)
for i := s - l + 2; i < s-5; i += 6 {
nextHash := hashLen(load6432(src, i), tableBits, hashBytes)
e.table[nextHash] = tableEntryPrev{
Prev: e.table[nextHash].Cur,
Cur: tableEntry{offset: e.cur + i}}
@ -185,23 +186,23 @@ func (e *fastEncL3) Encode(dst *tokens, src []byte) {
// 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)
prevHash := hashLen(x, tableBits, hashBytes)
e.table[prevHash] = tableEntryPrev{
Prev: e.table[prevHash].Cur,
Cur: tableEntry{offset: e.cur + s - 2},
}
x >>= 8
prevHash = hash4u(uint32(x), tableBits)
prevHash = hashLen(x, tableBits, hashBytes)
e.table[prevHash] = tableEntryPrev{
Prev: e.table[prevHash].Cur,
Cur: tableEntry{offset: e.cur + s - 1},
}
x >>= 8
currHash := hash4u(uint32(x), tableBits)
currHash := hashLen(x, tableBits, hashBytes)
candidates := e.table[currHash]
cv = uint32(x)
cv = x
e.table[currHash] = tableEntryPrev{
Prev: candidates.Cur,
Cur: tableEntry{offset: s + e.cur},
@ -212,17 +213,17 @@ func (e *fastEncL3) Encode(dst *tokens, src []byte) {
minOffset := e.cur + s - (maxMatchOffset - 4)
if candidate.offset > minOffset {
if cv == load3232(src, candidate.offset-e.cur) {
if uint32(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) {
if candidate.offset > minOffset && uint32(cv) == load3232(src, candidate.offset-e.cur) {
// Match at prev...
continue
}
}
cv = uint32(x >> 8)
cv = x >> 8
s++
break
}

View File

@ -12,6 +12,7 @@ func (e *fastEncL4) Encode(dst *tokens, src []byte) {
const (
inputMargin = 12 - 1
minNonLiteralBlockSize = 1 + 1 + inputMargin
hashShortBytes = 4
)
if debugDeflate && e.cur < 0 {
panic(fmt.Sprint("e.cur < 0: ", e.cur))
@ -80,7 +81,7 @@ func (e *fastEncL4) Encode(dst *tokens, src []byte) {
nextS := s
var t int32
for {
nextHashS := hash4x64(cv, tableBits)
nextHashS := hashLen(cv, tableBits, hashShortBytes)
nextHashL := hash7(cv, tableBits)
s = nextS
@ -168,7 +169,7 @@ func (e *fastEncL4) Encode(dst *tokens, src []byte) {
// 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.table[hashLen(cv, tableBits, hashShortBytes)] = tableEntry{offset: s + e.cur}
e.bTable[hash7(cv, tableBits)] = tableEntry{offset: s + e.cur}
}
goto emitRemainder
@ -183,7 +184,7 @@ func (e *fastEncL4) Encode(dst *tokens, src []byte) {
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
e.table[hashLen(cv>>8, tableBits, hashShortBytes)] = t2
i += 3
for ; i < s-1; i += 3 {
@ -192,7 +193,7 @@ func (e *fastEncL4) Encode(dst *tokens, src []byte) {
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
e.table[hashLen(cv>>8, tableBits, hashShortBytes)] = t2
}
}
}
@ -201,7 +202,7 @@ func (e *fastEncL4) Encode(dst *tokens, src []byte) {
// 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)
prevHashS := hashLen(x, tableBits, hashShortBytes)
prevHashL := hash7(x, tableBits)
e.table[prevHashS] = tableEntry{offset: o}
e.bTable[prevHashL] = tableEntry{offset: o}

View File

@ -12,6 +12,7 @@ func (e *fastEncL5) Encode(dst *tokens, src []byte) {
const (
inputMargin = 12 - 1
minNonLiteralBlockSize = 1 + 1 + inputMargin
hashShortBytes = 4
)
if debugDeflate && e.cur < 0 {
panic(fmt.Sprint("e.cur < 0: ", e.cur))
@ -88,7 +89,7 @@ func (e *fastEncL5) Encode(dst *tokens, src []byte) {
var l int32
var t int32
for {
nextHashS := hash4x64(cv, tableBits)
nextHashS := hashLen(cv, tableBits, hashShortBytes)
nextHashL := hash7(cv, tableBits)
s = nextS
@ -105,7 +106,7 @@ func (e *fastEncL5) Encode(dst *tokens, src []byte) {
eLong := &e.bTable[nextHashL]
eLong.Cur, eLong.Prev = entry, eLong.Cur
nextHashS = hash4x64(next, tableBits)
nextHashS = hashLen(next, tableBits, hashShortBytes)
nextHashL = hash7(next, tableBits)
t = lCandidate.Cur.offset - e.cur
@ -191,14 +192,21 @@ func (e *fastEncL5) Encode(dst *tokens, src []byte) {
// Try to locate a better match by checking the end of best match...
if sAt := s + l; l < 30 && sAt < sLimit {
// Allow some bytes at the beginning to mismatch.
// Sweet spot is 2/3 bytes depending on input.
// 3 is only a little better when it is but sometimes a lot worse.
// The skipped bytes are tested in Extend backwards,
// and still picked up as part of the match if they do.
const skipBeginning = 2
eLong := e.bTable[hash7(load6432(src, sAt), tableBits)].Cur.offset
// Test current
t2 := eLong - e.cur - l
off := s - t2
t2 := eLong - e.cur - l + skipBeginning
s2 := s + skipBeginning
off := s2 - t2
if t2 >= 0 && off < maxMatchOffset && off > 0 {
if l2 := e.matchlenLong(s, t2, src); l2 > l {
if l2 := e.matchlenLong(s2, t2, src); l2 > l {
t = t2
l = l2
s = s2
}
}
}
@ -250,7 +258,7 @@ func (e *fastEncL5) Encode(dst *tokens, src []byte) {
if i < s-1 {
cv := load6432(src, i)
t := tableEntry{offset: i + e.cur}
e.table[hash4x64(cv, tableBits)] = t
e.table[hashLen(cv, tableBits, hashShortBytes)] = t
eLong := &e.bTable[hash7(cv, tableBits)]
eLong.Cur, eLong.Prev = t, eLong.Cur
@ -263,7 +271,7 @@ func (e *fastEncL5) Encode(dst *tokens, src []byte) {
// 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
e.table[hashLen(cv, tableBits, hashShortBytes)] = t
// Skip one - otherwise we risk hitting 's'
i += 4
@ -273,7 +281,7 @@ func (e *fastEncL5) Encode(dst *tokens, src []byte) {
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
e.table[hashLen(cv>>8, tableBits, hashShortBytes)] = t2
}
}
}
@ -282,7 +290,7 @@ func (e *fastEncL5) Encode(dst *tokens, src []byte) {
// 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)
prevHashS := hashLen(x, tableBits, hashShortBytes)
prevHashL := hash7(x, tableBits)
e.table[prevHashS] = tableEntry{offset: o}
eLong := &e.bTable[prevHashL]

View File

@ -12,6 +12,7 @@ func (e *fastEncL6) Encode(dst *tokens, src []byte) {
const (
inputMargin = 12 - 1
minNonLiteralBlockSize = 1 + 1 + inputMargin
hashShortBytes = 4
)
if debugDeflate && e.cur < 0 {
panic(fmt.Sprint("e.cur < 0: ", e.cur))
@ -90,7 +91,7 @@ func (e *fastEncL6) Encode(dst *tokens, src []byte) {
var l int32
var t int32
for {
nextHashS := hash4x64(cv, tableBits)
nextHashS := hashLen(cv, tableBits, hashShortBytes)
nextHashL := hash7(cv, tableBits)
s = nextS
nextS = s + doEvery + (s-nextEmit)>>skipLog
@ -107,7 +108,7 @@ func (e *fastEncL6) Encode(dst *tokens, src []byte) {
eLong.Cur, eLong.Prev = entry, eLong.Cur
// Calculate hashes of 'next'
nextHashS = hash4x64(next, tableBits)
nextHashS = hashLen(next, tableBits, hashShortBytes)
nextHashL = hash7(next, tableBits)
t = lCandidate.Cur.offset - e.cur
@ -213,24 +214,33 @@ func (e *fastEncL6) Encode(dst *tokens, src []byte) {
// Try to locate a better match by checking the end-of-match...
if sAt := s + l; sAt < sLimit {
// Allow some bytes at the beginning to mismatch.
// Sweet spot is 2/3 bytes depending on input.
// 3 is only a little better when it is but sometimes a lot worse.
// The skipped bytes are tested in Extend backwards,
// and still picked up as part of the match if they do.
const skipBeginning = 2
eLong := &e.bTable[hash7(load6432(src, sAt), tableBits)]
// Test current
t2 := eLong.Cur.offset - e.cur - l
off := s - t2
t2 := eLong.Cur.offset - e.cur - l + skipBeginning
s2 := s + skipBeginning
off := s2 - t2
if off < maxMatchOffset {
if off > 0 && t2 >= 0 {
if l2 := e.matchlenLong(s, t2, src); l2 > l {
if l2 := e.matchlenLong(s2, t2, src); l2 > l {
t = t2
l = l2
s = s2
}
}
// Test next:
t2 = eLong.Prev.offset - e.cur - l
off := s - t2
t2 = eLong.Prev.offset - e.cur - l + skipBeginning
off := s2 - t2
if off > 0 && off < maxMatchOffset && t2 >= 0 {
if l2 := e.matchlenLong(s, t2, src); l2 > l {
if l2 := e.matchlenLong(s2, t2, src); l2 > l {
t = t2
l = l2
s = s2
}
}
}
@ -277,7 +287,7 @@ func (e *fastEncL6) Encode(dst *tokens, src []byte) {
// 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}
e.table[hashLen(cv, tableBits, hashShortBytes)] = tableEntry{offset: i + e.cur}
eLong := &e.bTable[hash7(cv, tableBits)]
eLong.Cur, eLong.Prev = tableEntry{offset: i + e.cur}, eLong.Cur
}
@ -292,7 +302,7 @@ func (e *fastEncL6) Encode(dst *tokens, src []byte) {
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
e.table[hashLen(cv, tableBits, hashShortBytes)] = t
eLong.Cur, eLong.Prev = t, eLong.Cur
eLong2.Cur, eLong2.Prev = t2, eLong2.Cur
}

View File

@ -86,11 +86,19 @@ func StatelessDeflate(out io.Writer, in []byte, eof bool, dict []byte) error {
dict = dict[len(dict)-maxStatelessDict:]
}
// For subsequent loops, keep shallow dict reference to avoid alloc+copy.
var inDict []byte
for len(in) > 0 {
todo := in
if len(todo) > maxStatelessBlock-len(dict) {
if len(inDict) > 0 {
if len(todo) > maxStatelessBlock-maxStatelessDict {
todo = todo[:maxStatelessBlock-maxStatelessDict]
}
} else if len(todo) > maxStatelessBlock-len(dict) {
todo = todo[:maxStatelessBlock-len(dict)]
}
inOrg := in
in = in[len(todo):]
uncompressed := todo
if len(dict) > 0 {
@ -102,7 +110,11 @@ func StatelessDeflate(out io.Writer, in []byte, eof bool, dict []byte) error {
todo = combined
}
// Compress
statelessEnc(&dst, todo, int16(len(dict)))
if len(inDict) == 0 {
statelessEnc(&dst, todo, int16(len(dict)))
} else {
statelessEnc(&dst, inDict[:maxStatelessDict+len(todo)], maxStatelessDict)
}
isEof := eof && len(in) == 0
if dst.n == 0 {
@ -119,7 +131,8 @@ func StatelessDeflate(out io.Writer, in []byte, eof bool, dict []byte) error {
}
if len(in) > 0 {
// Retain a dict if we have more
dict = todo[len(todo)-maxStatelessDict:]
inDict = inOrg[len(uncompressed)-maxStatelessDict:]
dict = nil
dst.Reset()
}
if bw.err != nil {

View File

@ -325,35 +325,35 @@ The content compressed in this mode is fully compatible with the standard decode
Snappy vs S2 **compression** speed on 16 core (32 thread) computer, using all threads and a single thread (1 CPU):
| File | S2 speed | S2 Throughput | S2 % smaller | S2 "better" | "better" throughput | "better" % smaller |
|-----------------------------------------------------------------------------------------------------|----------|---------------|--------------|-------------|---------------------|--------------------|
| [rawstudio-mint14.tar](https://files.klauspost.com/compress/rawstudio-mint14.7z) | 12.70x | 10556 MB/s | 7.35% | 4.15x | 3455 MB/s | 12.79% |
| (1 CPU) | 1.14x | 948 MB/s | - | 0.42x | 349 MB/s | - |
| [github-june-2days-2019.json](https://files.klauspost.com/compress/github-june-2days-2019.json.zst) | 17.13x | 14484 MB/s | 31.60% | 10.09x | 8533 MB/s | 37.71% |
| (1 CPU) | 1.33x | 1127 MB/s | - | 0.70x | 589 MB/s | - |
| [github-ranks-backup.bin](https://files.klauspost.com/compress/github-ranks-backup.bin.zst) | 15.14x | 12000 MB/s | -5.79% | 6.59x | 5223 MB/s | 5.80% |
| (1 CPU) | 1.11x | 877 MB/s | - | 0.47x | 370 MB/s | - |
| [consensus.db.10gb](https://files.klauspost.com/compress/consensus.db.10gb.zst) | 14.62x | 12116 MB/s | 15.90% | 5.35x | 4430 MB/s | 16.08% |
| (1 CPU) | 1.38x | 1146 MB/s | - | 0.38x | 312 MB/s | - |
| [adresser.json](https://files.klauspost.com/compress/adresser.json.zst) | 8.83x | 17579 MB/s | 43.86% | 6.54x | 13011 MB/s | 47.23% |
| (1 CPU) | 1.14x | 2259 MB/s | - | 0.74x | 1475 MB/s | - |
| [gob-stream](https://files.klauspost.com/compress/gob-stream.7z) | 16.72x | 14019 MB/s | 24.02% | 10.11x | 8477 MB/s | 30.48% |
| (1 CPU) | 1.24x | 1043 MB/s | - | 0.70x | 586 MB/s | - |
| [10gb.tar](http://mattmahoney.net/dc/10gb.html) | 13.33x | 9254 MB/s | 1.84% | 6.75x | 4686 MB/s | 6.72% |
| (1 CPU) | 0.97x | 672 MB/s | - | 0.53x | 366 MB/s | - |
| sharnd.out.2gb | 2.11x | 12639 MB/s | 0.01% | 1.98x | 11833 MB/s | 0.01% |
| (1 CPU) | 0.93x | 5594 MB/s | - | 1.34x | 8030 MB/s | - |
| [enwik9](http://mattmahoney.net/dc/textdata.html) | 19.34x | 8220 MB/s | 3.98% | 7.87x | 3345 MB/s | 15.82% |
| (1 CPU) | 1.06x | 452 MB/s | - | 0.50x | 213 MB/s | - |
| [silesia.tar](http://sun.aei.polsl.pl/~sdeor/corpus/silesia.zip) | 10.48x | 6124 MB/s | 5.67% | 3.76x | 2197 MB/s | 12.60% |
| (1 CPU) | 0.97x | 568 MB/s | - | 0.46x | 271 MB/s | - |
| [enwik10](https://encode.su/threads/3315-enwik10-benchmark-results) | 21.07x | 9020 MB/s | 6.36% | 6.91x | 2959 MB/s | 16.95% |
| (1 CPU) | 1.07x | 460 MB/s | - | 0.51x | 220 MB/s | - |
| File | S2 Speed | S2 Throughput | S2 % smaller | S2 "better" | "better" throughput | "better" % smaller |
|---------------------------------------------------------------------------------------------------------|----------|---------------|--------------|-------------|---------------------|--------------------|
| [rawstudio-mint14.tar](https://files.klauspost.com/compress/rawstudio-mint14.7z) | 16.33x | 10556 MB/s | 8.0% | 6.04x | 5252 MB/s | 14.7% |
| (1 CPU) | 1.08x | 940 MB/s | - | 0.46x | 400 MB/s | - |
| [github-june-2days-2019.json](https://files.klauspost.com/compress/github-june-2days-2019.json.zst) | 16.51x | 15224 MB/s | 31.70% | 9.47x | 8734 MB/s | 37.71% |
| (1 CPU) | 1.26x | 1157 MB/s | - | 0.60x | 556 MB/s | - |
| [github-ranks-backup.bin](https://files.klauspost.com/compress/github-ranks-backup.bin.zst) | 15.14x | 12598 MB/s | -5.76% | 6.23x | 5675 MB/s | 3.62% |
| (1 CPU) | 1.02x | 932 MB/s | - | 0.47x | 432 MB/s | - |
| [consensus.db.10gb](https://files.klauspost.com/compress/consensus.db.10gb.zst) | 11.21x | 12116 MB/s | 15.95% | 3.24x | 3500 MB/s | 18.00% |
| (1 CPU) | 1.05x | 1135 MB/s | - | 0.27x | 292 MB/s | - |
| [apache.log](https://files.klauspost.com/compress/apache.log.zst) | 8.55x | 16673 MB/s | 20.54% | 5.85x | 11420 MB/s | 24.97% |
| (1 CPU) | 1.91x | 1771 MB/s | - | 0.53x | 1041 MB/s | - |
| [gob-stream](https://files.klauspost.com/compress/gob-stream.7z) | 15.76x | 14357 MB/s | 24.01% | 8.67x | 7891 MB/s | 33.68% |
| (1 CPU) | 1.17x | 1064 MB/s | - | 0.65x | 595 MB/s | - |
| [10gb.tar](http://mattmahoney.net/dc/10gb.html) | 13.33x | 9835 MB/s | 2.34% | 6.85x | 4863 MB/s | 9.96% |
| (1 CPU) | 0.97x | 689 MB/s | - | 0.55x | 387 MB/s | - |
| sharnd.out.2gb | 9.11x | 13213 MB/s | 0.01% | 1.49x | 9184 MB/s | 0.01% |
| (1 CPU) | 0.88x | 5418 MB/s | - | 0.77x | 5417 MB/s | - |
| [sofia-air-quality-dataset csv](https://files.klauspost.com/compress/sofia-air-quality-dataset.tar.zst) | 22.00x | 11477 MB/s | 18.73% | 11.15x | 5817 MB/s | 27.88% |
| (1 CPU) | 1.23x | 642 MB/s | - | 0.71x | 642 MB/s | - |
| [silesia.tar](http://sun.aei.polsl.pl/~sdeor/corpus/silesia.zip) | 11.23x | 6520 MB/s | 5.9% | 5.35x | 3109 MB/s | 15.88% |
| (1 CPU) | 1.05x | 607 MB/s | - | 0.52x | 304 MB/s | - |
| [enwik9](https://files.klauspost.com/compress/enwik9.zst) | 19.28x | 8440 MB/s | 4.04% | 9.31x | 4076 MB/s | 18.04% |
| (1 CPU) | 1.12x | 488 MB/s | - | 0.57x | 250 MB/s | - |
### Legend
* `S2 speed`: Speed of S2 compared to Snappy, using 16 cores and 1 core.
* `S2 throughput`: Throughput of S2 in MB/s.
* `S2 Speed`: Speed of S2 compared to Snappy, using 16 cores and 1 core.
* `S2 Throughput`: Throughput of S2 in MB/s.
* `S2 % smaller`: How many percent of the Snappy output size is S2 better.
* `S2 "better"`: Speed when enabling "better" compression mode in S2 compared to Snappy.
* `"better" throughput`: Speed when enabling "better" compression mode in S2 compared to Snappy.
@ -361,7 +361,7 @@ Snappy vs S2 **compression** speed on 16 core (32 thread) computer, using all th
There is a good speedup across the board when using a single thread and a significant speedup when using multiple threads.
Machine generated data gets by far the biggest compression boost, with size being being reduced by up to 45% of Snappy size.
Machine generated data gets by far the biggest compression boost, with size being reduced by up to 35% of Snappy size.
The "better" compression mode sees a good improvement in all cases, but usually at a performance cost.
@ -404,15 +404,15 @@ The "better" compression mode will actively look for shorter matches, which is w
Without assembly decompression is also very fast; single goroutine decompression speed. No assembly:
| File | S2 Throughput | S2 throughput |
|--------------------------------|--------------|---------------|
| consensus.db.10gb.s2 | 1.84x | 2289.8 MB/s |
| 10gb.tar.s2 | 1.30x | 867.07 MB/s |
| rawstudio-mint14.tar.s2 | 1.66x | 1329.65 MB/s |
| github-june-2days-2019.json.s2 | 2.36x | 1831.59 MB/s |
| github-ranks-backup.bin.s2 | 1.73x | 1390.7 MB/s |
| enwik9.s2 | 1.67x | 681.53 MB/s |
| adresser.json.s2 | 3.41x | 4230.53 MB/s |
| silesia.tar.s2 | 1.52x | 811.58 |
|--------------------------------|---------------|---------------|
| consensus.db.10gb.s2 | 1.84x | 2289.8 MB/s |
| 10gb.tar.s2 | 1.30x | 867.07 MB/s |
| rawstudio-mint14.tar.s2 | 1.66x | 1329.65 MB/s |
| github-june-2days-2019.json.s2 | 2.36x | 1831.59 MB/s |
| github-ranks-backup.bin.s2 | 1.73x | 1390.7 MB/s |
| enwik9.s2 | 1.67x | 681.53 MB/s |
| adresser.json.s2 | 3.41x | 4230.53 MB/s |
| silesia.tar.s2 | 1.52x | 811.58 |
Even though S2 typically compresses better than Snappy, decompression speed is always better.
@ -450,14 +450,14 @@ The most reliable is a wide dataset.
For this we use [`webdevdata.org-2015-01-07-subset`](https://files.klauspost.com/compress/webdevdata.org-2015-01-07-4GB-subset.7z),
53927 files, total input size: 4,014,735,833 bytes. Single goroutine used.
| * | Input | Output | Reduction | MB/s |
|-------------------|------------|------------|-----------|--------|
| S2 | 4014735833 | 1059723369 | 73.60% | **934.34** |
| S2 Better | 4014735833 | 969670507 | 75.85% | 532.70 |
| S2 Best | 4014735833 | 906625668 | **77.85%** | 46.84 |
| Snappy | 4014735833 | 1128706759 | 71.89% | 762.59 |
| S2, Snappy Output | 4014735833 | 1093821420 | 72.75% | 908.60 |
| LZ4 | 4014735833 | 1079259294 | 73.12% | 526.94 |
| * | Input | Output | Reduction | MB/s |
|-------------------|------------|------------|------------|------------|
| S2 | 4014735833 | 1059723369 | 73.60% | **936.73** |
| S2 Better | 4014735833 | 961580539 | 76.05% | 451.10 |
| S2 Best | 4014735833 | 899182886 | **77.60%** | 46.84 |
| Snappy | 4014735833 | 1128706759 | 71.89% | 790.15 |
| S2, Snappy Output | 4014735833 | 1093823291 | 72.75% | 936.60 |
| LZ4 | 4014735833 | 1063768713 | 73.50% | 452.02 |
S2 delivers both the best single threaded throughput with regular mode and the best compression rate with "best".
"Better" mode provides the same compression speed as LZ4 with better compression ratio.
@ -489,43 +489,24 @@ AMD64 assembly is use for both S2 and Snappy.
| Absolute Perf | Snappy size | S2 Size | Snappy Speed | S2 Speed | Snappy dec | S2 dec |
|-----------------------|-------------|---------|--------------|-------------|-------------|-------------|
| html | 22843 | 21111 | 16246 MB/s | 17438 MB/s | 40972 MB/s | 49263 MB/s |
| urls.10K | 335492 | 287326 | 7943 MB/s | 9693 MB/s | 22523 MB/s | 26484 MB/s |
| fireworks.jpeg | 123034 | 123100 | 349544 MB/s | 273889 MB/s | 718321 MB/s | 827552 MB/s |
| fireworks.jpeg (200B) | 146 | 155 | 8869 MB/s | 17773 MB/s | 33691 MB/s | 52421 MB/s |
| paper-100k.pdf | 85304 | 84459 | 167546 MB/s | 101263 MB/s | 326905 MB/s | 291944 MB/s |
| html_x_4 | 92234 | 21113 | 15194 MB/s | 50670 MB/s | 30843 MB/s | 32217 MB/s |
| alice29.txt | 88034 | 85975 | 5936 MB/s | 6139 MB/s | 12882 MB/s | 20044 MB/s |
| asyoulik.txt | 77503 | 79650 | 5517 MB/s | 6366 MB/s | 12735 MB/s | 22806 MB/s |
| lcet10.txt | 234661 | 220670 | 6235 MB/s | 6067 MB/s | 14519 MB/s | 18697 MB/s |
| plrabn12.txt | 319267 | 317985 | 5159 MB/s | 5726 MB/s | 11923 MB/s | 19901 MB/s |
| geo.protodata | 23335 | 18690 | 21220 MB/s | 26529 MB/s | 56271 MB/s | 62540 MB/s |
| kppkn.gtb | 69526 | 65312 | 9732 MB/s | 8559 MB/s | 18491 MB/s | 18969 MB/s |
| alice29.txt (128B) | 80 | 82 | 6691 MB/s | 15489 MB/s | 31883 MB/s | 38874 MB/s |
| alice29.txt (1000B) | 774 | 774 | 12204 MB/s | 13000 MB/s | 48056 MB/s | 52341 MB/s |
| alice29.txt (10000B) | 6648 | 6933 | 10044 MB/s | 12806 MB/s | 32378 MB/s | 46322 MB/s |
| alice29.txt (20000B) | 12686 | 13574 | 7733 MB/s | 11210 MB/s | 30566 MB/s | 58969 MB/s |
| html | 22843 | 20868 | 16246 MB/s | 18617 MB/s | 40972 MB/s | 49263 MB/s |
| urls.10K | 335492 | 286541 | 7943 MB/s | 10201 MB/s | 22523 MB/s | 26484 MB/s |
| fireworks.jpeg | 123034 | 123100 | 349544 MB/s | 303228 MB/s | 718321 MB/s | 827552 MB/s |
| fireworks.jpeg (200B) | 146 | 155 | 8869 MB/s | 20180 MB/s | 33691 MB/s | 52421 MB/s |
| paper-100k.pdf | 85304 | 84202 | 167546 MB/s | 112988 MB/s | 326905 MB/s | 291944 MB/s |
| html_x_4 | 92234 | 20870 | 15194 MB/s | 54457 MB/s | 30843 MB/s | 32217 MB/s |
| alice29.txt | 88034 | 85934 | 5936 MB/s | 6540 MB/s | 12882 MB/s | 20044 MB/s |
| asyoulik.txt | 77503 | 79575 | 5517 MB/s | 6657 MB/s | 12735 MB/s | 22806 MB/s |
| lcet10.txt | 234661 | 220383 | 6235 MB/s | 6303 MB/s | 14519 MB/s | 18697 MB/s |
| plrabn12.txt | 319267 | 318196 | 5159 MB/s | 6074 MB/s | 11923 MB/s | 19901 MB/s |
| geo.protodata | 23335 | 18606 | 21220 MB/s | 25432 MB/s | 56271 MB/s | 62540 MB/s |
| kppkn.gtb | 69526 | 65019 | 9732 MB/s | 8905 MB/s | 18491 MB/s | 18969 MB/s |
| alice29.txt (128B) | 80 | 82 | 6691 MB/s | 17179 MB/s | 31883 MB/s | 38874 MB/s |
| alice29.txt (1000B) | 774 | 774 | 12204 MB/s | 13273 MB/s | 48056 MB/s | 52341 MB/s |
| alice29.txt (10000B) | 6648 | 6933 | 10044 MB/s | 12824 MB/s | 32378 MB/s | 46322 MB/s |
| alice29.txt (20000B) | 12686 | 13516 | 7733 MB/s | 12160 MB/s | 30566 MB/s | 58969 MB/s |
| Relative Perf | Snappy size | S2 size improved | S2 Speed | S2 Dec Speed |
|-----------------------|-------------|------------------|----------|--------------|
| html | 22.31% | 7.58% | 1.07x | 1.20x |
| urls.10K | 47.78% | 14.36% | 1.22x | 1.18x |
| fireworks.jpeg | 99.95% | -0.05% | 0.78x | 1.15x |
| fireworks.jpeg (200B) | 73.00% | -6.16% | 2.00x | 1.56x |
| paper-100k.pdf | 83.30% | 0.99% | 0.60x | 0.89x |
| html_x_4 | 22.52% | 77.11% | 3.33x | 1.04x |
| alice29.txt | 57.88% | 2.34% | 1.03x | 1.56x |
| asyoulik.txt | 61.91% | -2.77% | 1.15x | 1.79x |
| lcet10.txt | 54.99% | 5.96% | 0.97x | 1.29x |
| plrabn12.txt | 66.26% | 0.40% | 1.11x | 1.67x |
| geo.protodata | 19.68% | 19.91% | 1.25x | 1.11x |
| kppkn.gtb | 37.72% | 6.06% | 0.88x | 1.03x |
| alice29.txt (128B) | 62.50% | -2.50% | 2.31x | 1.22x |
| alice29.txt (1000B) | 77.40% | 0.00% | 1.07x | 1.09x |
| alice29.txt (10000B) | 66.48% | -4.29% | 1.27x | 1.43x |
| alice29.txt (20000B) | 63.43% | -7.00% | 1.45x | 1.93x |
Speed is generally at or above Snappy. Small blocks gets a significant speedup, although at the expense of size.
Decompression speed is better than Snappy, except in one case.
@ -543,43 +524,24 @@ So individual benchmarks should only be seen as a guideline and the overall pict
| Absolute Perf | Snappy size | Better Size | Snappy Speed | Better Speed | Snappy dec | Better dec |
|-----------------------|-------------|-------------|--------------|--------------|-------------|-------------|
| html | 22843 | 19833 | 16246 MB/s | 7731 MB/s | 40972 MB/s | 40292 MB/s |
| urls.10K | 335492 | 253529 | 7943 MB/s | 3980 MB/s | 22523 MB/s | 20981 MB/s |
| fireworks.jpeg | 123034 | 123100 | 349544 MB/s | 9760 MB/s | 718321 MB/s | 823698 MB/s |
| fireworks.jpeg (200B) | 146 | 142 | 8869 MB/s | 594 MB/s | 33691 MB/s | 30101 MB/s |
| paper-100k.pdf | 85304 | 82915 | 167546 MB/s | 7470 MB/s | 326905 MB/s | 198869 MB/s |
| html_x_4 | 92234 | 19841 | 15194 MB/s | 23403 MB/s | 30843 MB/s | 30937 MB/s |
| alice29.txt | 88034 | 73218 | 5936 MB/s | 2945 MB/s | 12882 MB/s | 16611 MB/s |
| asyoulik.txt | 77503 | 66844 | 5517 MB/s | 2739 MB/s | 12735 MB/s | 14975 MB/s |
| lcet10.txt | 234661 | 190589 | 6235 MB/s | 3099 MB/s | 14519 MB/s | 16634 MB/s |
| plrabn12.txt | 319267 | 270828 | 5159 MB/s | 2600 MB/s | 11923 MB/s | 13382 MB/s |
| geo.protodata | 23335 | 18278 | 21220 MB/s | 11208 MB/s | 56271 MB/s | 57961 MB/s |
| kppkn.gtb | 69526 | 61851 | 9732 MB/s | 4556 MB/s | 18491 MB/s | 16524 MB/s |
| alice29.txt (128B) | 80 | 81 | 6691 MB/s | 529 MB/s | 31883 MB/s | 34225 MB/s |
| alice29.txt (1000B) | 774 | 748 | 12204 MB/s | 1943 MB/s | 48056 MB/s | 42068 MB/s |
| alice29.txt (10000B) | 6648 | 6234 | 10044 MB/s | 2949 MB/s | 32378 MB/s | 28813 MB/s |
| alice29.txt (20000B) | 12686 | 11584 | 7733 MB/s | 2822 MB/s | 30566 MB/s | 27315 MB/s |
| html | 22843 | 18972 | 16246 MB/s | 8621 MB/s | 40972 MB/s | 40292 MB/s |
| urls.10K | 335492 | 248079 | 7943 MB/s | 5104 MB/s | 22523 MB/s | 20981 MB/s |
| fireworks.jpeg | 123034 | 123100 | 349544 MB/s | 84429 MB/s | 718321 MB/s | 823698 MB/s |
| fireworks.jpeg (200B) | 146 | 149 | 8869 MB/s | 7125 MB/s | 33691 MB/s | 30101 MB/s |
| paper-100k.pdf | 85304 | 82887 | 167546 MB/s | 11087 MB/s | 326905 MB/s | 198869 MB/s |
| html_x_4 | 92234 | 18982 | 15194 MB/s | 29316 MB/s | 30843 MB/s | 30937 MB/s |
| alice29.txt | 88034 | 71611 | 5936 MB/s | 3709 MB/s | 12882 MB/s | 16611 MB/s |
| asyoulik.txt | 77503 | 65941 | 5517 MB/s | 3380 MB/s | 12735 MB/s | 14975 MB/s |
| lcet10.txt | 234661 | 184939 | 6235 MB/s | 3537 MB/s | 14519 MB/s | 16634 MB/s |
| plrabn12.txt | 319267 | 264990 | 5159 MB/s | 2960 MB/s | 11923 MB/s | 13382 MB/s |
| geo.protodata | 23335 | 17689 | 21220 MB/s | 10859 MB/s | 56271 MB/s | 57961 MB/s |
| kppkn.gtb | 69526 | 55398 | 9732 MB/s | 5206 MB/s | 18491 MB/s | 16524 MB/s |
| alice29.txt (128B) | 80 | 78 | 6691 MB/s | 7422 MB/s | 31883 MB/s | 34225 MB/s |
| alice29.txt (1000B) | 774 | 746 | 12204 MB/s | 5734 MB/s | 48056 MB/s | 42068 MB/s |
| alice29.txt (10000B) | 6648 | 6218 | 10044 MB/s | 6055 MB/s | 32378 MB/s | 28813 MB/s |
| alice29.txt (20000B) | 12686 | 11492 | 7733 MB/s | 3143 MB/s | 30566 MB/s | 27315 MB/s |
| Relative Perf | Snappy size | Better size | Better Speed | Better dec |
|-----------------------|-------------|-------------|--------------|------------|
| html | 22.31% | 13.18% | 0.48x | 0.98x |
| urls.10K | 47.78% | 24.43% | 0.50x | 0.93x |
| fireworks.jpeg | 99.95% | -0.05% | 0.03x | 1.15x |
| fireworks.jpeg (200B) | 73.00% | 2.74% | 0.07x | 0.89x |
| paper-100k.pdf | 83.30% | 2.80% | 0.07x | 0.61x |
| html_x_4 | 22.52% | 78.49% | 0.04x | 1.00x |
| alice29.txt | 57.88% | 16.83% | 1.54x | 1.29x |
| asyoulik.txt | 61.91% | 13.75% | 0.50x | 1.18x |
| lcet10.txt | 54.99% | 18.78% | 0.50x | 1.15x |
| plrabn12.txt | 66.26% | 15.17% | 0.50x | 1.12x |
| geo.protodata | 19.68% | 21.67% | 0.50x | 1.03x |
| kppkn.gtb | 37.72% | 11.04% | 0.53x | 0.89x |
| alice29.txt (128B) | 62.50% | -1.25% | 0.47x | 1.07x |
| alice29.txt (1000B) | 77.40% | 3.36% | 0.08x | 0.88x |
| alice29.txt (10000B) | 66.48% | 6.23% | 0.16x | 0.89x |
| alice29.txt (20000B) | 63.43% | 8.69% | 0.29x | 0.89x |
Except for the mostly incompressible JPEG image compression is better and usually in the
double digits in terms of percentage reduction over Snappy.
@ -605,29 +567,29 @@ Some examples compared on 16 core CPU, amd64 assembly used:
```
* enwik10
Default... 10000000000 -> 4761467548 [47.61%]; 1.098s, 8685.6MB/s
Better... 10000000000 -> 4219438251 [42.19%]; 1.925s, 4954.2MB/s
Best... 10000000000 -> 3627364337 [36.27%]; 43.051s, 221.5MB/s
Default... 10000000000 -> 4759950115 [47.60%]; 1.03s, 9263.0MB/s
Better... 10000000000 -> 4084706676 [40.85%]; 2.16s, 4415.4MB/s
Best... 10000000000 -> 3615520079 [36.16%]; 42.259s, 225.7MB/s
* github-june-2days-2019.json
Default... 6273951764 -> 1043196283 [16.63%]; 431ms, 13882.3MB/s
Better... 6273951764 -> 949146808 [15.13%]; 547ms, 10938.4MB/s
Best... 6273951764 -> 832855506 [13.27%]; 9.455s, 632.8MB/s
Default... 6273951764 -> 1041700255 [16.60%]; 431ms, 13882.3MB/s
Better... 6273951764 -> 945841238 [15.08%]; 547ms, 10938.4MB/s
Best... 6273951764 -> 826392576 [13.17%]; 9.455s, 632.8MB/s
* nyc-taxi-data-10M.csv
Default... 3325605752 -> 1095998837 [32.96%]; 324ms, 9788.7MB/s
Better... 3325605752 -> 954776589 [28.71%]; 491ms, 6459.4MB/s
Best... 3325605752 -> 779098746 [23.43%]; 8.29s, 382.6MB/s
Default... 3325605752 -> 1093516949 [32.88%]; 324ms, 9788.7MB/s
Better... 3325605752 -> 885394158 [26.62%]; 491ms, 6459.4MB/s
Best... 3325605752 -> 773681257 [23.26%]; 8.29s, 412.0MB/s
* 10gb.tar
Default... 10065157632 -> 5916578242 [58.78%]; 1.028s, 9337.4MB/s
Better... 10065157632 -> 5649207485 [56.13%]; 1.597s, 6010.6MB/s
Best... 10065157632 -> 5208719802 [51.75%]; 32.78s, 292.8MB/
Default... 10065157632 -> 5915541066 [58.77%]; 1.028s, 9337.4MB/s
Better... 10065157632 -> 5453844650 [54.19%]; 1.597s, 4862.7MB/s
Best... 10065157632 -> 5192495021 [51.59%]; 32.78s, 308.2MB/
* consensus.db.10gb
Default... 10737418240 -> 4562648848 [42.49%]; 882ms, 11610.0MB/s
Better... 10737418240 -> 4542428129 [42.30%]; 1.533s, 6679.7MB/s
Best... 10737418240 -> 4244773384 [39.53%]; 42.96s, 238.4MB/s
Default... 10737418240 -> 4549762344 [42.37%]; 882ms, 12118.4MB/s
Better... 10737418240 -> 4438535064 [41.34%]; 1.533s, 3500.9MB/s
Best... 10737418240 -> 4210602774 [39.21%]; 42.96s, 254.4MB/s
```
Decompression speed should be around the same as using the 'better' compression mode.
@ -648,10 +610,10 @@ If you would like more control, you can use the s2 package as described below:
Snappy compatible blocks can be generated with the S2 encoder.
Compression and speed is typically a bit better `MaxEncodedLen` is also smaller for smaller memory usage. Replace
| Snappy | S2 replacement |
|----------------------------|-------------------------|
| snappy.Encode(...) | s2.EncodeSnappy(...) |
| snappy.MaxEncodedLen(...) | s2.MaxEncodedLen(...) |
| Snappy | S2 replacement |
|---------------------------|-----------------------|
| snappy.Encode(...) | s2.EncodeSnappy(...) |
| snappy.MaxEncodedLen(...) | s2.MaxEncodedLen(...) |
`s2.EncodeSnappy` can be replaced with `s2.EncodeSnappyBetter` or `s2.EncodeSnappyBest` to get more efficiently compressed snappy compatible output.
@ -660,12 +622,12 @@ Compression and speed is typically a bit better `MaxEncodedLen` is also smaller
Comparison of [`webdevdata.org-2015-01-07-subset`](https://files.klauspost.com/compress/webdevdata.org-2015-01-07-4GB-subset.7z),
53927 files, total input size: 4,014,735,833 bytes. amd64, single goroutine used:
| Encoder | Size | MB/s | Reduction |
|-----------------------|------------|------------|------------
| snappy.Encode | 1128706759 | 725.59 | 71.89% |
| s2.EncodeSnappy | 1093823291 | **899.16** | 72.75% |
| s2.EncodeSnappyBetter | 1001158548 | 578.49 | 75.06% |
| s2.EncodeSnappyBest | 944507998 | 66.00 | **76.47%**|
| Encoder | Size | MB/s | Reduction |
|-----------------------|------------|------------|------------|
| snappy.Encode | 1128706759 | 725.59 | 71.89% |
| s2.EncodeSnappy | 1093823291 | **899.16** | 72.75% |
| s2.EncodeSnappyBetter | 1001158548 | 578.49 | 75.06% |
| s2.EncodeSnappyBest | 944507998 | 66.00 | **76.47%** |
## Streams
@ -835,6 +797,13 @@ This is done using the regular "Skip" function:
This will ensure that we are at exactly the offset we want, and reading from `dec` will start at the requested offset.
# Compact storage
For compact storage [RemoveIndexHeaders](https://pkg.go.dev/github.com/klauspost/compress/s2#RemoveIndexHeaders) can be used to remove any redundant info from
a serialized index. If you remove the header it must be restored before [Loading](https://pkg.go.dev/github.com/klauspost/compress/s2#Index.Load).
This is expected to save 20 bytes. These can be restored using [RestoreIndexHeaders](https://pkg.go.dev/github.com/klauspost/compress/s2#RestoreIndexHeaders). This removes a layer of security, but is the most compact representation. Returns nil if headers contains errors.
## Index Format:
Each block is structured as a snappy skippable block, with the chunk ID 0x99.
@ -844,20 +813,20 @@ The block can be read from the front, but contains information so it can be read
Numbers are stored as fixed size little endian values or [zigzag encoded](https://developers.google.com/protocol-buffers/docs/encoding#signed_integers) [base 128 varints](https://developers.google.com/protocol-buffers/docs/encoding),
with un-encoded value length of 64 bits, unless other limits are specified.
| Content | Format |
|---------------------------------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------|
| ID, `[1]byte` | Always 0x99. |
| Data Length, `[3]byte` | 3 byte little-endian length of the chunk in bytes, following this. |
| Header `[6]byte` | Header, must be `[115, 50, 105, 100, 120, 0]` or in text: "s2idx\x00". |
| UncompressedSize, Varint | Total Uncompressed size. |
| CompressedSize, Varint | Total Compressed size if known. Should be -1 if unknown. |
| EstBlockSize, Varint | Block Size, used for guessing uncompressed offsets. Must be >= 0. |
| Entries, Varint | Number of Entries in index, must be < 65536 and >=0. |
| HasUncompressedOffsets `byte` | 0 if no uncompressed offsets are present, 1 if present. Other values are invalid. |
| UncompressedOffsets, [Entries]VarInt | Uncompressed offsets. See below how to decode. |
| CompressedOffsets, [Entries]VarInt | Compressed offsets. See below how to decode. |
| Block Size, `[4]byte` | Little Endian total encoded size (including header and trailer). Can be used for searching backwards to start of block. |
| Trailer `[6]byte` | Trailer, must be `[0, 120, 100, 105, 50, 115]` or in text: "\x00xdi2s". Can be used for identifying block from end of stream. |
| Content | Format |
|--------------------------------------|-------------------------------------------------------------------------------------------------------------------------------|
| ID, `[1]byte` | Always 0x99. |
| Data Length, `[3]byte` | 3 byte little-endian length of the chunk in bytes, following this. |
| Header `[6]byte` | Header, must be `[115, 50, 105, 100, 120, 0]` or in text: "s2idx\x00". |
| UncompressedSize, Varint | Total Uncompressed size. |
| CompressedSize, Varint | Total Compressed size if known. Should be -1 if unknown. |
| EstBlockSize, Varint | Block Size, used for guessing uncompressed offsets. Must be >= 0. |
| Entries, Varint | Number of Entries in index, must be < 65536 and >=0. |
| HasUncompressedOffsets `byte` | 0 if no uncompressed offsets are present, 1 if present. Other values are invalid. |
| UncompressedOffsets, [Entries]VarInt | Uncompressed offsets. See below how to decode. |
| CompressedOffsets, [Entries]VarInt | Compressed offsets. See below how to decode. |
| Block Size, `[4]byte` | Little Endian total encoded size (including header and trailer). Can be used for searching backwards to start of block. |
| Trailer `[6]byte` | Trailer, must be `[0, 120, 100, 105, 50, 115]` or in text: "\x00xdi2s". Can be used for identifying block from end of stream. |
For regular streams the uncompressed offsets are fully predictable,
so `HasUncompressedOffsets` allows to specify that compressed blocks all have
@ -929,6 +898,7 @@ To decode from any given uncompressed offset `(wantOffset)`:
See [using indexes](https://github.com/klauspost/compress/tree/master/s2#using-indexes) for functions that perform the operations with a simpler interface.
# Format Extensions
* Frame [Stream identifier](https://github.com/google/snappy/blob/master/framing_format.txt#L68) changed from `sNaPpY` to `S2sTwO`.
@ -951,10 +921,11 @@ The length is specified by reading the 3-bit length specified in the tag and dec
| 7 | 65540 + read 3 bytes |
This allows any repeat offset + length to be represented by 2 to 5 bytes.
It also allows to emit matches longer than 64 bytes with one copy + one repeat instead of several 64 byte copies.
Lengths are stored as little endian values.
The first copy of a block cannot be a repeat offset and the offset is not carried across blocks in streams.
The first copy of a block cannot be a repeat offset and the offset is reset on every block in streams.
Default streaming block size is 1MB.

View File

@ -952,7 +952,11 @@ func (r *Reader) ReadSeeker(random bool, index []byte) (*ReadSeeker, error) {
// Seek allows seeking in compressed data.
func (r *ReadSeeker) Seek(offset int64, whence int) (int64, error) {
if r.err != nil {
return 0, r.err
if !errors.Is(r.err, io.EOF) {
return 0, r.err
}
// Reset on EOF
r.err = nil
}
if offset == 0 && whence == io.SeekCurrent {
return r.blockStart + int64(r.i), nil

View File

@ -28,6 +28,9 @@ func s2Decode(dst, src []byte) int {
// As long as we can read at least 5 bytes...
for s < len(src)-5 {
// Removing bounds checks is SLOWER, when if doing
// in := src[s:s+5]
// Checked on Go 1.18
switch src[s] & 0x03 {
case tagLiteral:
x := uint32(src[s] >> 2)
@ -38,14 +41,19 @@ func s2Decode(dst, src []byte) int {
s += 2
x = uint32(src[s-1])
case x == 61:
in := src[s : s+3]
x = uint32(in[1]) | uint32(in[2])<<8
s += 3
x = uint32(src[s-2]) | uint32(src[s-1])<<8
case x == 62:
in := src[s : s+4]
// Load as 32 bit and shift down.
x = uint32(in[0]) | uint32(in[1])<<8 | uint32(in[2])<<16 | uint32(in[3])<<24
x >>= 8
s += 4
x = uint32(src[s-3]) | uint32(src[s-2])<<8 | uint32(src[s-1])<<16
case x == 63:
in := src[s : s+5]
x = uint32(in[1]) | uint32(in[2])<<8 | uint32(in[3])<<16 | uint32(in[4])<<24
s += 5
x = uint32(src[s-4]) | uint32(src[s-3])<<8 | uint32(src[s-2])<<16 | uint32(src[s-1])<<24
}
length = int(x) + 1
if length > len(dst)-d || length > len(src)-s || (strconv.IntSize == 32 && length <= 0) {
@ -62,8 +70,8 @@ func s2Decode(dst, src []byte) int {
case tagCopy1:
s += 2
length = int(src[s-2]) >> 2 & 0x7
toffset := int(uint32(src[s-2])&0xe0<<3 | uint32(src[s-1]))
length = int(src[s-2]) >> 2 & 0x7
if toffset == 0 {
if debug {
fmt.Print("(repeat) ")
@ -71,14 +79,16 @@ func s2Decode(dst, src []byte) int {
// keep last offset
switch length {
case 5:
length = int(src[s]) + 4
s += 1
length = int(uint32(src[s-1])) + 4
case 6:
in := src[s : s+2]
length = int(uint32(in[0])|(uint32(in[1])<<8)) + (1 << 8)
s += 2
length = int(uint32(src[s-2])|(uint32(src[s-1])<<8)) + (1 << 8)
case 7:
in := src[s : s+3]
length = int((uint32(in[2])<<16)|(uint32(in[1])<<8)|uint32(in[0])) + (1 << 16)
s += 3
length = int(uint32(src[s-3])|(uint32(src[s-2])<<8)|(uint32(src[s-1])<<16)) + (1 << 16)
default: // 0-> 4
}
} else {
@ -86,14 +96,16 @@ func s2Decode(dst, src []byte) int {
}
length += 4
case tagCopy2:
in := src[s : s+3]
offset = int(uint32(in[1]) | uint32(in[2])<<8)
length = 1 + int(in[0])>>2
s += 3
length = 1 + int(src[s-3])>>2
offset = int(uint32(src[s-2]) | uint32(src[s-1])<<8)
case tagCopy4:
in := src[s : s+5]
offset = int(uint32(in[1]) | uint32(in[2])<<8 | uint32(in[3])<<16 | uint32(in[4])<<24)
length = 1 + int(in[0])>>2
s += 5
length = 1 + int(src[s-5])>>2
offset = int(uint32(src[s-4]) | uint32(src[s-3])<<8 | uint32(src[s-2])<<16 | uint32(src[s-1])<<24)
}
if offset <= 0 || d < offset || length > len(dst)-d {

View File

@ -58,8 +58,9 @@ func encodeGo(dst, src []byte) []byte {
// been written.
//
// It also assumes that:
//
// len(dst) >= MaxEncodedLen(len(src)) &&
// minNonLiteralBlockSize <= len(src) && len(src) <= maxBlockSize
// minNonLiteralBlockSize <= len(src) && len(src) <= maxBlockSize
func encodeBlockGo(dst, src []byte) (d int) {
// Initialize the hash table.
const (

View File

@ -8,8 +8,9 @@ package s2
// been written.
//
// It also assumes that:
//
// len(dst) >= MaxEncodedLen(len(src)) &&
// minNonLiteralBlockSize <= len(src) && len(src) <= maxBlockSize
// minNonLiteralBlockSize <= len(src) && len(src) <= maxBlockSize
func encodeBlock(dst, src []byte) (d int) {
const (
// Use 12 bit table when less than...
@ -43,8 +44,9 @@ func encodeBlock(dst, src []byte) (d int) {
// been written.
//
// It also assumes that:
//
// len(dst) >= MaxEncodedLen(len(src)) &&
// minNonLiteralBlockSize <= len(src) && len(src) <= maxBlockSize
// minNonLiteralBlockSize <= len(src) && len(src) <= maxBlockSize
func encodeBlockBetter(dst, src []byte) (d int) {
const (
// Use 12 bit table when less than...
@ -78,8 +80,9 @@ func encodeBlockBetter(dst, src []byte) (d int) {
// been written.
//
// It also assumes that:
//
// len(dst) >= MaxEncodedLen(len(src)) &&
// minNonLiteralBlockSize <= len(src) && len(src) <= maxBlockSize
// minNonLiteralBlockSize <= len(src) && len(src) <= maxBlockSize
func encodeBlockSnappy(dst, src []byte) (d int) {
const (
// Use 12 bit table when less than...
@ -112,8 +115,9 @@ func encodeBlockSnappy(dst, src []byte) (d int) {
// been written.
//
// It also assumes that:
//
// len(dst) >= MaxEncodedLen(len(src)) &&
// minNonLiteralBlockSize <= len(src) && len(src) <= maxBlockSize
// minNonLiteralBlockSize <= len(src) && len(src) <= maxBlockSize
func encodeBlockBetterSnappy(dst, src []byte) (d int) {
const (
// Use 12 bit table when less than...

View File

@ -15,8 +15,9 @@ import (
// been written.
//
// It also assumes that:
//
// len(dst) >= MaxEncodedLen(len(src)) &&
// minNonLiteralBlockSize <= len(src) && len(src) <= maxBlockSize
// minNonLiteralBlockSize <= len(src) && len(src) <= maxBlockSize
func encodeBlockBest(dst, src []byte) (d int) {
// Initialize the hash tables.
const (
@ -176,14 +177,21 @@ func encodeBlockBest(dst, src []byte) (d int) {
best = bestOf(best, matchAt(getPrev(nextLong), s, uint32(cv), false))
}
// Search for a match at best match end, see if that is better.
if sAt := best.s + best.length; sAt < sLimit {
sBack := best.s
backL := best.length
// Allow some bytes at the beginning to mismatch.
// Sweet spot is around 1-2 bytes, but depends on input.
// The skipped bytes are tested in Extend backwards,
// and still picked up as part of the match if they do.
const skipBeginning = 2
const skipEnd = 1
if sAt := best.s + best.length - skipEnd; sAt < sLimit {
sBack := best.s + skipBeginning - skipEnd
backL := best.length - skipBeginning
// Load initial values
cv = load64(src, sBack)
// Search for mismatch
// Grab candidates...
next := lTable[hash8(load64(src, sAt), lTableBits)]
//next := sTable[hash4(load64(src, sAt), sTableBits)]
if checkAt := getCur(next) - backL; checkAt > 0 {
best = bestOf(best, matchAt(checkAt, sBack, uint32(cv), false))
@ -191,6 +199,16 @@ func encodeBlockBest(dst, src []byte) (d int) {
if checkAt := getPrev(next) - backL; checkAt > 0 {
best = bestOf(best, matchAt(checkAt, sBack, uint32(cv), false))
}
// Disabled: Extremely small gain
if false {
next = sTable[hash4(load64(src, sAt), sTableBits)]
if checkAt := getCur(next) - backL; checkAt > 0 {
best = bestOf(best, matchAt(checkAt, sBack, uint32(cv), false))
}
if checkAt := getPrev(next) - backL; checkAt > 0 {
best = bestOf(best, matchAt(checkAt, sBack, uint32(cv), false))
}
}
}
}
}
@ -288,8 +306,9 @@ emitRemainder:
// been written.
//
// It also assumes that:
//
// len(dst) >= MaxEncodedLen(len(src)) &&
// minNonLiteralBlockSize <= len(src) && len(src) <= maxBlockSize
// minNonLiteralBlockSize <= len(src) && len(src) <= maxBlockSize
func encodeBlockBestSnappy(dst, src []byte) (d int) {
// Initialize the hash tables.
const (
@ -546,6 +565,7 @@ emitRemainder:
// emitCopySize returns the size to encode the offset+length
//
// It assumes that:
//
// 1 <= offset && offset <= math.MaxUint32
// 4 <= length && length <= 1 << 24
func emitCopySize(offset, length int) int {
@ -584,6 +604,7 @@ func emitCopySize(offset, length int) int {
// emitCopyNoRepeatSize returns the size to encode the offset+length
//
// It assumes that:
//
// 1 <= offset && offset <= math.MaxUint32
// 4 <= length && length <= 1 << 24
func emitCopyNoRepeatSize(offset, length int) int {

View File

@ -42,8 +42,9 @@ func hash8(u uint64, h uint8) uint32 {
// been written.
//
// It also assumes that:
//
// len(dst) >= MaxEncodedLen(len(src)) &&
// minNonLiteralBlockSize <= len(src) && len(src) <= maxBlockSize
// minNonLiteralBlockSize <= len(src) && len(src) <= maxBlockSize
func encodeBlockBetterGo(dst, src []byte) (d int) {
// 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
@ -56,7 +57,7 @@ func encodeBlockBetterGo(dst, src []byte) (d int) {
// Initialize the hash tables.
const (
// Long hash matches.
lTableBits = 16
lTableBits = 17
maxLTableSize = 1 << lTableBits
// Short hash matches.
@ -97,9 +98,26 @@ func encodeBlockBetterGo(dst, src []byte) (d int) {
lTable[hashL] = uint32(s)
sTable[hashS] = uint32(s)
valLong := load64(src, candidateL)
valShort := load64(src, candidateS)
// If long matches at least 8 bytes, use that.
if cv == valLong {
break
}
if cv == valShort {
candidateL = candidateS
break
}
// Check repeat at offset checkRep.
const checkRep = 1
if false && uint32(cv>>(checkRep*8)) == load32(src, s-repeat+checkRep) {
// Minimum length of a repeat. Tested with various values.
// While 4-5 offers improvements in some, 6 reduces
// regressions significantly.
const wantRepeatBytes = 6
const repeatMask = ((1 << (wantRepeatBytes * 8)) - 1) << (8 * checkRep)
if false && repeat > 0 && cv&repeatMask == load64(src, s-repeat)&repeatMask {
base := s + checkRep
// Extend back
for i := base - repeat; base > nextEmit && i > 0 && src[i-1] == src[base-1]; {
@ -109,8 +127,8 @@ func encodeBlockBetterGo(dst, src []byte) (d int) {
d += emitLiteral(dst[d:], src[nextEmit:base])
// Extend forward
candidate := s - repeat + 4 + checkRep
s += 4 + checkRep
candidate := s - repeat + wantRepeatBytes + checkRep
s += wantRepeatBytes + checkRep
for s < len(src) {
if len(src)-s < 8 {
if src[s] == src[candidate] {
@ -127,28 +145,40 @@ func encodeBlockBetterGo(dst, src []byte) (d int) {
s += 8
candidate += 8
}
if nextEmit > 0 {
// same as `add := emitCopy(dst[d:], repeat, s-base)` but skips storing offset.
d += emitRepeat(dst[d:], repeat, s-base)
} else {
// First match, cannot be repeat.
d += emitCopy(dst[d:], repeat, s-base)
}
// same as `add := emitCopy(dst[d:], repeat, s-base)` but skips storing offset.
d += emitRepeat(dst[d:], repeat, s-base)
nextEmit = s
if s >= sLimit {
goto emitRemainder
}
// Index in-between
index0 := base + 1
index1 := s - 2
cv = load64(src, s)
for index0 < index1 {
cv0 := load64(src, index0)
cv1 := load64(src, index1)
lTable[hash7(cv0, lTableBits)] = uint32(index0)
sTable[hash4(cv0>>8, sTableBits)] = uint32(index0 + 1)
lTable[hash7(cv1, lTableBits)] = uint32(index1)
sTable[hash4(cv1>>8, sTableBits)] = uint32(index1 + 1)
index0 += 2
index1 -= 2
}
cv = load64(src, s)
continue
}
if uint32(cv) == load32(src, candidateL) {
// Long likely matches 7, so take that.
if uint32(cv) == uint32(valLong) {
break
}
// Check our short candidate
if uint32(cv) == load32(src, candidateS) {
if uint32(cv) == uint32(valShort) {
// Try a long candidate at s+1
hashL = hash7(cv>>8, lTableBits)
candidateL = int(lTable[hashL])
@ -227,21 +257,29 @@ func encodeBlockBetterGo(dst, src []byte) (d int) {
// Do we have space for more, if not bail.
return 0
}
// Index match start+1 (long) and start+2 (short)
// Index short & long
index0 := base + 1
// Index match end-2 (long) and end-1 (short)
index1 := s - 2
cv0 := load64(src, index0)
cv1 := load64(src, index1)
cv = load64(src, s)
lTable[hash7(cv0, lTableBits)] = uint32(index0)
lTable[hash7(cv0>>8, lTableBits)] = uint32(index0 + 1)
lTable[hash7(cv1, lTableBits)] = uint32(index1)
lTable[hash7(cv1>>8, lTableBits)] = uint32(index1 + 1)
sTable[hash4(cv0>>8, sTableBits)] = uint32(index0 + 1)
sTable[hash4(cv0>>16, sTableBits)] = uint32(index0 + 2)
lTable[hash7(cv1, lTableBits)] = uint32(index1)
sTable[hash4(cv1>>8, sTableBits)] = uint32(index1 + 1)
index0 += 1
index1 -= 1
cv = load64(src, s)
// index every second long in between.
for index0 < index1 {
lTable[hash7(load64(src, index0), lTableBits)] = uint32(index0)
lTable[hash7(load64(src, index1), lTableBits)] = uint32(index1)
index0 += 2
index1 -= 2
}
}
emitRemainder:
@ -260,8 +298,9 @@ emitRemainder:
// been written.
//
// It also assumes that:
//
// len(dst) >= MaxEncodedLen(len(src)) &&
// minNonLiteralBlockSize <= len(src) && len(src) <= maxBlockSize
// minNonLiteralBlockSize <= len(src) && len(src) <= maxBlockSize
func encodeBlockBetterSnappyGo(dst, src []byte) (d int) {
// 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
@ -402,21 +441,29 @@ func encodeBlockBetterSnappyGo(dst, src []byte) (d int) {
// Do we have space for more, if not bail.
return 0
}
// Index match start+1 (long) and start+2 (short)
// Index short & long
index0 := base + 1
// Index match end-2 (long) and end-1 (short)
index1 := s - 2
cv0 := load64(src, index0)
cv1 := load64(src, index1)
cv = load64(src, s)
lTable[hash7(cv0, lTableBits)] = uint32(index0)
lTable[hash7(cv0>>8, lTableBits)] = uint32(index0 + 1)
lTable[hash7(cv1, lTableBits)] = uint32(index1)
lTable[hash7(cv1>>8, lTableBits)] = uint32(index1 + 1)
sTable[hash4(cv0>>8, sTableBits)] = uint32(index0 + 1)
sTable[hash4(cv0>>16, sTableBits)] = uint32(index0 + 2)
lTable[hash7(cv1, lTableBits)] = uint32(index1)
sTable[hash4(cv1>>8, sTableBits)] = uint32(index1 + 1)
index0 += 1
index1 -= 1
cv = load64(src, s)
// index every second long in between.
for index0 < index1 {
lTable[hash7(load64(src, index0), lTableBits)] = uint32(index0)
lTable[hash7(load64(src, index1), lTableBits)] = uint32(index1)
index0 += 2
index1 -= 2
}
}
emitRemainder:

View File

@ -12,6 +12,7 @@ import (
// been written.
//
// It also assumes that:
//
// len(dst) >= MaxEncodedLen(len(src))
func encodeBlock(dst, src []byte) (d int) {
if len(src) < minNonLiteralBlockSize {
@ -25,6 +26,7 @@ func encodeBlock(dst, src []byte) (d int) {
// been written.
//
// It also assumes that:
//
// len(dst) >= MaxEncodedLen(len(src))
func encodeBlockBetter(dst, src []byte) (d int) {
return encodeBlockBetterGo(dst, src)
@ -35,6 +37,7 @@ func encodeBlockBetter(dst, src []byte) (d int) {
// been written.
//
// It also assumes that:
//
// len(dst) >= MaxEncodedLen(len(src))
func encodeBlockBetterSnappy(dst, src []byte) (d int) {
return encodeBlockBetterSnappyGo(dst, src)
@ -45,6 +48,7 @@ func encodeBlockBetterSnappy(dst, src []byte) (d int) {
// been written.
//
// It also assumes that:
//
// len(dst) >= MaxEncodedLen(len(src))
func encodeBlockSnappy(dst, src []byte) (d int) {
if len(src) < minNonLiteralBlockSize {
@ -56,6 +60,7 @@ func encodeBlockSnappy(dst, src []byte) (d int) {
// emitLiteral writes a literal chunk and returns the number of bytes written.
//
// It assumes that:
//
// dst is long enough to hold the encoded bytes
// 0 <= len(lit) && len(lit) <= math.MaxUint32
func emitLiteral(dst, lit []byte) int {
@ -146,6 +151,7 @@ func emitRepeat(dst []byte, offset, length int) int {
// emitCopy writes a copy chunk and returns the number of bytes written.
//
// It assumes that:
//
// dst is long enough to hold the encoded bytes
// 1 <= offset && offset <= math.MaxUint32
// 4 <= length && length <= 1 << 24
@ -214,6 +220,7 @@ func emitCopy(dst []byte, offset, length int) int {
// emitCopyNoRepeat writes a copy chunk and returns the number of bytes written.
//
// It assumes that:
//
// dst is long enough to hold the encoded bytes
// 1 <= offset && offset <= math.MaxUint32
// 4 <= length && length <= 1 << 24
@ -273,8 +280,8 @@ func emitCopyNoRepeat(dst []byte, offset, length int) int {
// matchLen returns how many bytes match in a and b
//
// It assumes that:
// len(a) <= len(b)
//
// len(a) <= len(b)
func matchLen(a []byte, b []byte) int {
b = b[:len(a)]
var checked int

View File

@ -1,7 +1,6 @@
// Code generated by command: go run gen.go -out ../encodeblock_amd64.s -stubs ../encodeblock_amd64.go -pkg=s2. DO NOT EDIT.
//go:build !appengine && !noasm && gc && !noasm
// +build !appengine,!noasm,gc,!noasm
package s2
@ -150,8 +149,9 @@ func encodeSnappyBetterBlockAsm8B(dst []byte, src []byte) int
// emitLiteral writes a literal chunk and returns the number of bytes written.
//
// It assumes that:
// dst is long enough to hold the encoded bytes with margin of 0 bytes
// 0 <= len(lit) && len(lit) <= math.MaxUint32
//
// dst is long enough to hold the encoded bytes with margin of 0 bytes
// 0 <= len(lit) && len(lit) <= math.MaxUint32
//
//go:noescape
func emitLiteral(dst []byte, lit []byte) int
@ -165,9 +165,10 @@ func emitRepeat(dst []byte, offset int, length int) int
// emitCopy writes a copy chunk and returns the number of bytes written.
//
// It assumes that:
// dst is long enough to hold the encoded bytes
// 1 <= offset && offset <= math.MaxUint32
// 4 <= length && length <= 1 << 24
//
// dst is long enough to hold the encoded bytes
// 1 <= offset && offset <= math.MaxUint32
// 4 <= length && length <= 1 << 24
//
//go:noescape
func emitCopy(dst []byte, offset int, length int) int
@ -175,9 +176,10 @@ func emitCopy(dst []byte, offset int, length int) int
// emitCopyNoRepeat writes a copy chunk and returns the number of bytes written.
//
// It assumes that:
// dst is long enough to hold the encoded bytes
// 1 <= offset && offset <= math.MaxUint32
// 4 <= length && length <= 1 << 24
//
// dst is long enough to hold the encoded bytes
// 1 <= offset && offset <= math.MaxUint32
// 4 <= length && length <= 1 << 24
//
//go:noescape
func emitCopyNoRepeat(dst []byte, offset int, length int) int
@ -185,7 +187,8 @@ func emitCopyNoRepeat(dst []byte, offset int, length int) int
// matchLen returns how many bytes match in a and b
//
// It assumes that:
// len(a) <= len(b)
//
// len(a) <= len(b)
//
//go:noescape
func matchLen(a []byte, b []byte) int

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