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Update c/image after https://github.com/containers/image/pull/1810
Signed-off-by: Miloslav Trmač <mitr@redhat.com>
This commit is contained in:
Miloslav Trmač
123
vendor/github.com/klauspost/compress/flate/deflate.go
generated
vendored
123
vendor/github.com/klauspost/compress/flate/deflate.go
generated
vendored
@@ -294,7 +294,6 @@ func (d *compressor) findMatch(pos int, prevHead int, lookahead int) (length, of
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}
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offset = 0
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cGain := 0
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if d.chain < 100 {
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for i := prevHead; tries > 0; tries-- {
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if wEnd == win[i+length] {
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@@ -322,10 +321,14 @@ func (d *compressor) findMatch(pos int, prevHead int, lookahead int) (length, of
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return
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}
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// Minimum gain to accept a match.
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cGain := 4
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// Some like it higher (CSV), some like it lower (JSON)
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const baseCost = 6
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const baseCost = 3
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// Base is 4 bytes at with an additional cost.
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// Matches must be better than this.
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for i := prevHead; tries > 0; tries-- {
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if wEnd == win[i+length] {
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n := matchLen(win[i:i+minMatchLook], wPos)
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@@ -333,7 +336,7 @@ func (d *compressor) findMatch(pos int, prevHead int, lookahead int) (length, of
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// Calculate gain. Estimate
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newGain := d.h.bitLengthRaw(wPos[:n]) - int(offsetExtraBits[offsetCode(uint32(pos-i))]) - baseCost - int(lengthExtraBits[lengthCodes[(n-3)&255]])
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//fmt.Println(n, "gain:", newGain, "prev:", cGain, "raw:", d.h.bitLengthRaw(wPos[:n]))
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//fmt.Println("gain:", newGain, "prev:", cGain, "raw:", d.h.bitLengthRaw(wPos[:n]), "this-len:", n, "prev-len:", length)
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if newGain > cGain {
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length = n
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offset = pos - i
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@@ -490,27 +493,103 @@ func (d *compressor) deflateLazy() {
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}
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if prevLength >= minMatchLength && s.length <= prevLength {
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// Check for better match at end...
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// No better match, but check for better match at end...
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//
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// checkOff must be >=2 since we otherwise risk checking s.index
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// Offset of 2 seems to yield best results.
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// Skip forward a number of bytes.
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// Offset of 2 seems to yield best results. 3 is sometimes better.
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const checkOff = 2
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prevIndex := s.index - 1
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if prevIndex+prevLength+checkOff < s.maxInsertIndex {
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end := lookahead
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if lookahead > maxMatchLength {
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end = maxMatchLength
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}
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end += prevIndex
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idx := prevIndex + prevLength - (4 - checkOff)
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h := hash4(d.window[idx:])
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ch2 := int(s.hashHead[h]) - s.hashOffset - prevLength + (4 - checkOff)
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if ch2 > minIndex {
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length := matchLen(d.window[prevIndex:end], d.window[ch2:])
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// It seems like a pure length metric is best.
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if length > prevLength {
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prevLength = length
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prevOffset = prevIndex - ch2
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// Check all, except full length
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if prevLength < maxMatchLength-checkOff {
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prevIndex := s.index - 1
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if prevIndex+prevLength < s.maxInsertIndex {
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end := lookahead
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if lookahead > maxMatchLength+checkOff {
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end = maxMatchLength + checkOff
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}
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end += prevIndex
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// Hash at match end.
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h := hash4(d.window[prevIndex+prevLength:])
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ch2 := int(s.hashHead[h]) - s.hashOffset - prevLength
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if prevIndex-ch2 != prevOffset && ch2 > minIndex+checkOff {
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length := matchLen(d.window[prevIndex+checkOff:end], d.window[ch2+checkOff:])
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// It seems like a pure length metric is best.
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if length > prevLength {
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prevLength = length
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prevOffset = prevIndex - ch2
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// Extend back...
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for i := checkOff - 1; i >= 0; i-- {
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if prevLength >= maxMatchLength || d.window[prevIndex+i] != d.window[ch2+i] {
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// Emit tokens we "owe"
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for j := 0; j <= i; j++ {
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d.tokens.AddLiteral(d.window[prevIndex+j])
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if d.tokens.n == maxFlateBlockTokens {
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// The block includes the current character
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if d.err = d.writeBlock(&d.tokens, s.index, false); d.err != nil {
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return
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}
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d.tokens.Reset()
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}
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s.index++
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if s.index < s.maxInsertIndex {
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h := hash4(d.window[s.index:])
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ch := s.hashHead[h]
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s.chainHead = int(ch)
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s.hashPrev[s.index&windowMask] = ch
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s.hashHead[h] = uint32(s.index + s.hashOffset)
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}
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}
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break
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} else {
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prevLength++
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}
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}
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} else if false {
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// Check one further ahead.
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// Only rarely better, disabled for now.
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prevIndex++
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h := hash4(d.window[prevIndex+prevLength:])
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ch2 := int(s.hashHead[h]) - s.hashOffset - prevLength
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if prevIndex-ch2 != prevOffset && ch2 > minIndex+checkOff {
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length := matchLen(d.window[prevIndex+checkOff:end], d.window[ch2+checkOff:])
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// It seems like a pure length metric is best.
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if length > prevLength+checkOff {
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prevLength = length
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prevOffset = prevIndex - ch2
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prevIndex--
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// Extend back...
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for i := checkOff; i >= 0; i-- {
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if prevLength >= maxMatchLength || d.window[prevIndex+i] != d.window[ch2+i-1] {
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// Emit tokens we "owe"
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for j := 0; j <= i; j++ {
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d.tokens.AddLiteral(d.window[prevIndex+j])
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if d.tokens.n == maxFlateBlockTokens {
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// The block includes the current character
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if d.err = d.writeBlock(&d.tokens, s.index, false); d.err != nil {
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return
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}
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d.tokens.Reset()
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}
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s.index++
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if s.index < s.maxInsertIndex {
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h := hash4(d.window[s.index:])
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ch := s.hashHead[h]
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s.chainHead = int(ch)
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s.hashPrev[s.index&windowMask] = ch
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s.hashHead[h] = uint32(s.index + s.hashOffset)
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}
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}
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break
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} else {
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prevLength++
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}
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}
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}
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}
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}
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}
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}
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}
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