[VOL-5486] Fix deprecated versions
Change-Id: If0b888d6c2f33b2f415c8b03b08dc994bb3df3f4
Signed-off-by: Abhay Kumar <abhay.kumar@radisys.com>
diff --git a/vendor/github.com/klauspost/compress/flate/deflate.go b/vendor/github.com/klauspost/compress/flate/deflate.go
new file mode 100644
index 0000000..af53fb8
--- /dev/null
+++ b/vendor/github.com/klauspost/compress/flate/deflate.go
@@ -0,0 +1,1017 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Copyright (c) 2015 Klaus Post
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package flate
+
+import (
+ "encoding/binary"
+ "errors"
+ "fmt"
+ "io"
+ "math"
+)
+
+const (
+ NoCompression = 0
+ BestSpeed = 1
+ BestCompression = 9
+ DefaultCompression = -1
+
+ // HuffmanOnly disables Lempel-Ziv match searching and only performs Huffman
+ // entropy encoding. This mode is useful in compressing data that has
+ // already been compressed with an LZ style algorithm (e.g. Snappy or LZ4)
+ // that lacks an entropy encoder. Compression gains are achieved when
+ // certain bytes in the input stream occur more frequently than others.
+ //
+ // Note that HuffmanOnly produces a compressed output that is
+ // RFC 1951 compliant. That is, any valid DEFLATE decompressor will
+ // continue to be able to decompress this output.
+ HuffmanOnly = -2
+ ConstantCompression = HuffmanOnly // compatibility alias.
+
+ logWindowSize = 15
+ windowSize = 1 << logWindowSize
+ windowMask = windowSize - 1
+ logMaxOffsetSize = 15 // Standard DEFLATE
+ minMatchLength = 4 // The smallest match that the compressor looks for
+ maxMatchLength = 258 // The longest match for the compressor
+ minOffsetSize = 1 // The shortest offset that makes any sense
+
+ // The maximum number of tokens we will encode at the time.
+ // Smaller sizes usually creates less optimal blocks.
+ // Bigger can make context switching slow.
+ // We use this for levels 7-9, so we make it big.
+ maxFlateBlockTokens = 1 << 15
+ maxStoreBlockSize = 65535
+ hashBits = 17 // After 17 performance degrades
+ hashSize = 1 << hashBits
+ hashMask = (1 << hashBits) - 1
+ hashShift = (hashBits + minMatchLength - 1) / minMatchLength
+ maxHashOffset = 1 << 28
+
+ skipNever = math.MaxInt32
+
+ debugDeflate = false
+)
+
+type compressionLevel struct {
+ good, lazy, nice, chain, fastSkipHashing, level int
+}
+
+// Compression levels have been rebalanced from zlib deflate defaults
+// to give a bigger spread in speed and compression.
+// See https://blog.klauspost.com/rebalancing-deflate-compression-levels/
+var levels = []compressionLevel{
+ {}, // 0
+ // Level 1-6 uses specialized algorithm - values not used
+ {0, 0, 0, 0, 0, 1},
+ {0, 0, 0, 0, 0, 2},
+ {0, 0, 0, 0, 0, 3},
+ {0, 0, 0, 0, 0, 4},
+ {0, 0, 0, 0, 0, 5},
+ {0, 0, 0, 0, 0, 6},
+ // Levels 7-9 use increasingly more lazy matching
+ // and increasingly stringent conditions for "good enough".
+ {8, 12, 16, 24, skipNever, 7},
+ {16, 30, 40, 64, skipNever, 8},
+ {32, 258, 258, 1024, skipNever, 9},
+}
+
+// advancedState contains state for the advanced levels, with bigger hash tables, etc.
+type advancedState struct {
+ // deflate state
+ length int
+ offset int
+ maxInsertIndex int
+ chainHead int
+ hashOffset int
+
+ ii uint16 // position of last match, intended to overflow to reset.
+
+ // input window: unprocessed data is window[index:windowEnd]
+ index int
+ hashMatch [maxMatchLength + minMatchLength]uint32
+
+ // Input hash chains
+ // hashHead[hashValue] contains the largest inputIndex with the specified hash value
+ // If hashHead[hashValue] is within the current window, then
+ // hashPrev[hashHead[hashValue] & windowMask] contains the previous index
+ // with the same hash value.
+ hashHead [hashSize]uint32
+ hashPrev [windowSize]uint32
+}
+
+type compressor struct {
+ compressionLevel
+
+ h *huffmanEncoder
+ w *huffmanBitWriter
+
+ // compression algorithm
+ fill func(*compressor, []byte) int // copy data to window
+ step func(*compressor) // process window
+
+ window []byte
+ windowEnd int
+ blockStart int // window index where current tokens start
+ err error
+
+ // queued output tokens
+ tokens tokens
+ fast fastEnc
+ state *advancedState
+
+ sync bool // requesting flush
+ byteAvailable bool // if true, still need to process window[index-1].
+}
+
+func (d *compressor) fillDeflate(b []byte) int {
+ s := d.state
+ if s.index >= 2*windowSize-(minMatchLength+maxMatchLength) {
+ // shift the window by windowSize
+ //copy(d.window[:], d.window[windowSize:2*windowSize])
+ *(*[windowSize]byte)(d.window) = *(*[windowSize]byte)(d.window[windowSize:])
+ s.index -= windowSize
+ d.windowEnd -= windowSize
+ if d.blockStart >= windowSize {
+ d.blockStart -= windowSize
+ } else {
+ d.blockStart = math.MaxInt32
+ }
+ s.hashOffset += windowSize
+ if s.hashOffset > maxHashOffset {
+ delta := s.hashOffset - 1
+ s.hashOffset -= delta
+ s.chainHead -= delta
+ // Iterate over slices instead of arrays to avoid copying
+ // the entire table onto the stack (Issue #18625).
+ for i, v := range s.hashPrev[:] {
+ if int(v) > delta {
+ s.hashPrev[i] = uint32(int(v) - delta)
+ } else {
+ s.hashPrev[i] = 0
+ }
+ }
+ for i, v := range s.hashHead[:] {
+ if int(v) > delta {
+ s.hashHead[i] = uint32(int(v) - delta)
+ } else {
+ s.hashHead[i] = 0
+ }
+ }
+ }
+ }
+ n := copy(d.window[d.windowEnd:], b)
+ d.windowEnd += n
+ return n
+}
+
+func (d *compressor) writeBlock(tok *tokens, index int, eof bool) error {
+ if index > 0 || eof {
+ var window []byte
+ if d.blockStart <= index {
+ window = d.window[d.blockStart:index]
+ }
+ d.blockStart = index
+ //d.w.writeBlock(tok, eof, window)
+ d.w.writeBlockDynamic(tok, eof, window, d.sync)
+ return d.w.err
+ }
+ return nil
+}
+
+// writeBlockSkip writes the current block and uses the number of tokens
+// to determine if the block should be stored on no matches, or
+// only huffman encoded.
+func (d *compressor) writeBlockSkip(tok *tokens, index int, eof bool) error {
+ if index > 0 || eof {
+ if d.blockStart <= index {
+ window := d.window[d.blockStart:index]
+ // If we removed less than a 64th of all literals
+ // we huffman compress the block.
+ if int(tok.n) > len(window)-int(tok.n>>6) {
+ d.w.writeBlockHuff(eof, window, d.sync)
+ } else {
+ // Write a dynamic huffman block.
+ d.w.writeBlockDynamic(tok, eof, window, d.sync)
+ }
+ } else {
+ d.w.writeBlock(tok, eof, nil)
+ }
+ d.blockStart = index
+ return d.w.err
+ }
+ return nil
+}
+
+// fillWindow will fill the current window with the supplied
+// dictionary and calculate all hashes.
+// This is much faster than doing a full encode.
+// Should only be used after a start/reset.
+func (d *compressor) fillWindow(b []byte) {
+ // Do not fill window if we are in store-only or huffman mode.
+ if d.level <= 0 && d.level > -MinCustomWindowSize {
+ return
+ }
+ if d.fast != nil {
+ // encode the last data, but discard the result
+ if len(b) > maxMatchOffset {
+ b = b[len(b)-maxMatchOffset:]
+ }
+ d.fast.Encode(&d.tokens, b)
+ d.tokens.Reset()
+ return
+ }
+ s := d.state
+ // If we are given too much, cut it.
+ if len(b) > windowSize {
+ b = b[len(b)-windowSize:]
+ }
+ // Add all to window.
+ n := copy(d.window[d.windowEnd:], b)
+
+ // Calculate 256 hashes at the time (more L1 cache hits)
+ loops := (n + 256 - minMatchLength) / 256
+ for j := 0; j < loops; j++ {
+ startindex := j * 256
+ end := startindex + 256 + minMatchLength - 1
+ if end > n {
+ end = n
+ }
+ tocheck := d.window[startindex:end]
+ dstSize := len(tocheck) - minMatchLength + 1
+
+ if dstSize <= 0 {
+ continue
+ }
+
+ dst := s.hashMatch[:dstSize]
+ bulkHash4(tocheck, dst)
+ var newH uint32
+ for i, val := range dst {
+ di := i + startindex
+ newH = val & hashMask
+ // Get previous value with the same hash.
+ // Our chain should point to the previous value.
+ s.hashPrev[di&windowMask] = s.hashHead[newH]
+ // Set the head of the hash chain to us.
+ s.hashHead[newH] = uint32(di + s.hashOffset)
+ }
+ }
+ // Update window information.
+ d.windowEnd += n
+ s.index = n
+}
+
+// Try to find a match starting at index whose length is greater than prevSize.
+// We only look at chainCount possibilities before giving up.
+// pos = s.index, prevHead = s.chainHead-s.hashOffset, prevLength=minMatchLength-1, lookahead
+func (d *compressor) findMatch(pos int, prevHead int, lookahead int) (length, offset int, ok bool) {
+ minMatchLook := maxMatchLength
+ if lookahead < minMatchLook {
+ minMatchLook = lookahead
+ }
+
+ win := d.window[0 : pos+minMatchLook]
+
+ // We quit when we get a match that's at least nice long
+ nice := len(win) - pos
+ if d.nice < nice {
+ nice = d.nice
+ }
+
+ // If we've got a match that's good enough, only look in 1/4 the chain.
+ tries := d.chain
+ length = minMatchLength - 1
+
+ wEnd := win[pos+length]
+ wPos := win[pos:]
+ minIndex := pos - windowSize
+ if minIndex < 0 {
+ minIndex = 0
+ }
+ offset = 0
+
+ if d.chain < 100 {
+ for i := prevHead; tries > 0; tries-- {
+ if wEnd == win[i+length] {
+ n := matchLen(win[i:i+minMatchLook], wPos)
+ if n > length {
+ length = n
+ offset = pos - i
+ ok = true
+ if n >= nice {
+ // The match is good enough that we don't try to find a better one.
+ break
+ }
+ wEnd = win[pos+n]
+ }
+ }
+ if i <= minIndex {
+ // hashPrev[i & windowMask] has already been overwritten, so stop now.
+ break
+ }
+ i = int(d.state.hashPrev[i&windowMask]) - d.state.hashOffset
+ if i < minIndex {
+ break
+ }
+ }
+ return
+ }
+
+ // Minimum gain to accept a match.
+ cGain := 4
+
+ // Some like it higher (CSV), some like it lower (JSON)
+ 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)
+ if n > length {
+ // Calculate gain. Estimate
+ newGain := d.h.bitLengthRaw(wPos[:n]) - int(offsetExtraBits[offsetCode(uint32(pos-i))]) - baseCost - int(lengthExtraBits[lengthCodes[(n-3)&255]])
+
+ //fmt.Println("gain:", newGain, "prev:", cGain, "raw:", d.h.bitLengthRaw(wPos[:n]), "this-len:", n, "prev-len:", length)
+ if newGain > cGain {
+ length = n
+ offset = pos - i
+ cGain = newGain
+ ok = true
+ if n >= nice {
+ // The match is good enough that we don't try to find a better one.
+ break
+ }
+ wEnd = win[pos+n]
+ }
+ }
+ }
+ if i <= minIndex {
+ // hashPrev[i & windowMask] has already been overwritten, so stop now.
+ break
+ }
+ i = int(d.state.hashPrev[i&windowMask]) - d.state.hashOffset
+ if i < minIndex {
+ break
+ }
+ }
+ return
+}
+
+func (d *compressor) writeStoredBlock(buf []byte) error {
+ if d.w.writeStoredHeader(len(buf), false); d.w.err != nil {
+ return d.w.err
+ }
+ d.w.writeBytes(buf)
+ return d.w.err
+}
+
+// hash4 returns a hash representation of the first 4 bytes
+// of the supplied slice.
+// The caller must ensure that len(b) >= 4.
+func hash4(b []byte) uint32 {
+ return hash4u(binary.LittleEndian.Uint32(b), hashBits)
+}
+
+// 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) {
+ if len(b) < 4 {
+ return
+ }
+ hb := binary.LittleEndian.Uint32(b)
+
+ dst[0] = hash4u(hb, hashBits)
+ end := len(b) - 4 + 1
+ for i := 1; i < end; i++ {
+ hb = (hb >> 8) | uint32(b[i+3])<<24
+ dst[i] = hash4u(hb, hashBits)
+ }
+}
+
+func (d *compressor) initDeflate() {
+ d.window = make([]byte, 2*windowSize)
+ d.byteAvailable = false
+ d.err = nil
+ if d.state == nil {
+ return
+ }
+ s := d.state
+ s.index = 0
+ s.hashOffset = 1
+ s.length = minMatchLength - 1
+ s.offset = 0
+ s.chainHead = -1
+}
+
+// deflateLazy is the same as deflate, but with d.fastSkipHashing == skipNever,
+// meaning it always has lazy matching on.
+func (d *compressor) deflateLazy() {
+ s := d.state
+ // Sanity enables additional runtime tests.
+ // It's intended to be used during development
+ // to supplement the currently ad-hoc unit tests.
+ const sanity = debugDeflate
+
+ if d.windowEnd-s.index < minMatchLength+maxMatchLength && !d.sync {
+ return
+ }
+ if d.windowEnd != s.index && d.chain > 100 {
+ // Get literal huffman coder.
+ if d.h == nil {
+ d.h = newHuffmanEncoder(maxFlateBlockTokens)
+ }
+ var tmp [256]uint16
+ for _, v := range d.window[s.index:d.windowEnd] {
+ tmp[v]++
+ }
+ d.h.generate(tmp[:], 15)
+ }
+
+ s.maxInsertIndex = d.windowEnd - (minMatchLength - 1)
+
+ for {
+ if sanity && s.index > d.windowEnd {
+ panic("index > windowEnd")
+ }
+ lookahead := d.windowEnd - s.index
+ if lookahead < minMatchLength+maxMatchLength {
+ if !d.sync {
+ return
+ }
+ if sanity && s.index > d.windowEnd {
+ panic("index > windowEnd")
+ }
+ if lookahead == 0 {
+ // Flush current output block if any.
+ if d.byteAvailable {
+ // There is still one pending token that needs to be flushed
+ d.tokens.AddLiteral(d.window[s.index-1])
+ d.byteAvailable = false
+ }
+ if d.tokens.n > 0 {
+ if d.err = d.writeBlock(&d.tokens, s.index, false); d.err != nil {
+ return
+ }
+ d.tokens.Reset()
+ }
+ return
+ }
+ }
+ if s.index < s.maxInsertIndex {
+ // Update the hash
+ hash := hash4(d.window[s.index:])
+ ch := s.hashHead[hash]
+ s.chainHead = int(ch)
+ s.hashPrev[s.index&windowMask] = ch
+ s.hashHead[hash] = uint32(s.index + s.hashOffset)
+ }
+ prevLength := s.length
+ prevOffset := s.offset
+ s.length = minMatchLength - 1
+ s.offset = 0
+ minIndex := s.index - windowSize
+ if minIndex < 0 {
+ minIndex = 0
+ }
+
+ if s.chainHead-s.hashOffset >= minIndex && lookahead > prevLength && prevLength < d.lazy {
+ if newLength, newOffset, ok := d.findMatch(s.index, s.chainHead-s.hashOffset, lookahead); ok {
+ s.length = newLength
+ s.offset = newOffset
+ }
+ }
+
+ if prevLength >= minMatchLength && s.length <= prevLength {
+ // No better match, but check for better match at end...
+ //
+ // Skip forward a number of bytes.
+ // Offset of 2 seems to yield best results. 3 is sometimes better.
+ const checkOff = 2
+
+ // 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++
+ }
+ }
+ }
+ }
+ }
+ }
+ }
+ }
+ // There was a match at the previous step, and the current match is
+ // not better. Output the previous match.
+ d.tokens.AddMatch(uint32(prevLength-3), uint32(prevOffset-minOffsetSize))
+
+ // Insert in the hash table all strings up to the end of the match.
+ // index and index-1 are already inserted. If there is not enough
+ // lookahead, the last two strings are not inserted into the hash
+ // table.
+ newIndex := s.index + prevLength - 1
+ // Calculate missing hashes
+ end := newIndex
+ if end > s.maxInsertIndex {
+ end = s.maxInsertIndex
+ }
+ end += minMatchLength - 1
+ startindex := s.index + 1
+ if startindex > s.maxInsertIndex {
+ startindex = s.maxInsertIndex
+ }
+ tocheck := d.window[startindex:end]
+ dstSize := len(tocheck) - minMatchLength + 1
+ if dstSize > 0 {
+ dst := s.hashMatch[:dstSize]
+ bulkHash4(tocheck, dst)
+ var newH uint32
+ for i, val := range dst {
+ di := i + startindex
+ newH = val & hashMask
+ // Get previous value with the same hash.
+ // Our chain should point to the previous value.
+ s.hashPrev[di&windowMask] = s.hashHead[newH]
+ // Set the head of the hash chain to us.
+ s.hashHead[newH] = uint32(di + s.hashOffset)
+ }
+ }
+
+ s.index = newIndex
+ d.byteAvailable = false
+ s.length = minMatchLength - 1
+ if d.tokens.n == maxFlateBlockTokens {
+ // The block includes the current character
+ if d.err = d.writeBlock(&d.tokens, s.index, false); d.err != nil {
+ return
+ }
+ d.tokens.Reset()
+ }
+ s.ii = 0
+ } else {
+ // Reset, if we got a match this run.
+ if s.length >= minMatchLength {
+ s.ii = 0
+ }
+ // We have a byte waiting. Emit it.
+ if d.byteAvailable {
+ s.ii++
+ d.tokens.AddLiteral(d.window[s.index-1])
+ if d.tokens.n == maxFlateBlockTokens {
+ if d.err = d.writeBlock(&d.tokens, s.index, false); d.err != nil {
+ return
+ }
+ d.tokens.Reset()
+ }
+ s.index++
+
+ // If we have a long run of no matches, skip additional bytes
+ // Resets when s.ii overflows after 64KB.
+ if n := int(s.ii) - d.chain; n > 0 {
+ n = 1 + int(n>>6)
+ for j := 0; j < n; j++ {
+ if s.index >= d.windowEnd-1 {
+ break
+ }
+ d.tokens.AddLiteral(d.window[s.index-1])
+ if d.tokens.n == maxFlateBlockTokens {
+ if d.err = d.writeBlock(&d.tokens, s.index, false); d.err != nil {
+ return
+ }
+ d.tokens.Reset()
+ }
+ // Index...
+ if s.index < s.maxInsertIndex {
+ h := hash4(d.window[s.index:])
+ ch := s.hashHead[h]
+ s.chainHead = int(ch)
+ s.hashPrev[s.index&windowMask] = ch
+ s.hashHead[h] = uint32(s.index + s.hashOffset)
+ }
+ s.index++
+ }
+ // Flush last byte
+ d.tokens.AddLiteral(d.window[s.index-1])
+ d.byteAvailable = false
+ // s.length = minMatchLength - 1 // not needed, since s.ii is reset above, so it should never be > minMatchLength
+ if d.tokens.n == maxFlateBlockTokens {
+ if d.err = d.writeBlock(&d.tokens, s.index, false); d.err != nil {
+ return
+ }
+ d.tokens.Reset()
+ }
+ }
+ } else {
+ s.index++
+ d.byteAvailable = true
+ }
+ }
+ }
+}
+
+func (d *compressor) store() {
+ if d.windowEnd > 0 && (d.windowEnd == maxStoreBlockSize || d.sync) {
+ d.err = d.writeStoredBlock(d.window[:d.windowEnd])
+ d.windowEnd = 0
+ }
+}
+
+// fillWindow will fill the buffer with data for huffman-only compression.
+// The number of bytes copied is returned.
+func (d *compressor) fillBlock(b []byte) int {
+ n := copy(d.window[d.windowEnd:], b)
+ d.windowEnd += n
+ return n
+}
+
+// storeHuff will compress and store the currently added data,
+// if enough has been accumulated or we at the end of the stream.
+// Any error that occurred will be in d.err
+func (d *compressor) storeHuff() {
+ if d.windowEnd < len(d.window) && !d.sync || d.windowEnd == 0 {
+ return
+ }
+ d.w.writeBlockHuff(false, d.window[:d.windowEnd], d.sync)
+ d.err = d.w.err
+ d.windowEnd = 0
+}
+
+// storeFast will compress and store the currently added data,
+// if enough has been accumulated or we at the end of the stream.
+// Any error that occurred will be in d.err
+func (d *compressor) storeFast() {
+ // We only compress if we have maxStoreBlockSize.
+ if d.windowEnd < len(d.window) {
+ if !d.sync {
+ return
+ }
+ // Handle extremely small sizes.
+ if d.windowEnd < 128 {
+ if d.windowEnd == 0 {
+ return
+ }
+ if d.windowEnd <= 32 {
+ d.err = d.writeStoredBlock(d.window[:d.windowEnd])
+ } else {
+ d.w.writeBlockHuff(false, d.window[:d.windowEnd], true)
+ d.err = d.w.err
+ }
+ d.tokens.Reset()
+ d.windowEnd = 0
+ d.fast.Reset()
+ return
+ }
+ }
+
+ d.fast.Encode(&d.tokens, d.window[:d.windowEnd])
+ // If we made zero matches, store the block as is.
+ if d.tokens.n == 0 {
+ d.err = d.writeStoredBlock(d.window[:d.windowEnd])
+ // If we removed less than 1/16th, huffman compress the block.
+ } else if int(d.tokens.n) > d.windowEnd-(d.windowEnd>>4) {
+ d.w.writeBlockHuff(false, d.window[:d.windowEnd], d.sync)
+ d.err = d.w.err
+ } else {
+ d.w.writeBlockDynamic(&d.tokens, false, d.window[:d.windowEnd], d.sync)
+ d.err = d.w.err
+ }
+ d.tokens.Reset()
+ d.windowEnd = 0
+}
+
+// write will add input byte to the stream.
+// Unless an error occurs all bytes will be consumed.
+func (d *compressor) write(b []byte) (n int, err error) {
+ if d.err != nil {
+ return 0, d.err
+ }
+ n = len(b)
+ for len(b) > 0 {
+ if d.windowEnd == len(d.window) || d.sync {
+ d.step(d)
+ }
+ b = b[d.fill(d, b):]
+ if d.err != nil {
+ return 0, d.err
+ }
+ }
+ return n, d.err
+}
+
+func (d *compressor) syncFlush() error {
+ d.sync = true
+ if d.err != nil {
+ return d.err
+ }
+ d.step(d)
+ if d.err == nil {
+ d.w.writeStoredHeader(0, false)
+ d.w.flush()
+ d.err = d.w.err
+ }
+ d.sync = false
+ return d.err
+}
+
+func (d *compressor) init(w io.Writer, level int) (err error) {
+ d.w = newHuffmanBitWriter(w)
+
+ switch {
+ case level == NoCompression:
+ d.window = make([]byte, maxStoreBlockSize)
+ d.fill = (*compressor).fillBlock
+ d.step = (*compressor).store
+ case level == ConstantCompression:
+ d.w.logNewTablePenalty = 10
+ d.window = make([]byte, 32<<10)
+ d.fill = (*compressor).fillBlock
+ d.step = (*compressor).storeHuff
+ case level == DefaultCompression:
+ level = 5
+ fallthrough
+ case level >= 1 && level <= 6:
+ d.w.logNewTablePenalty = 7
+ d.fast = newFastEnc(level)
+ d.window = make([]byte, maxStoreBlockSize)
+ d.fill = (*compressor).fillBlock
+ d.step = (*compressor).storeFast
+ case 7 <= level && level <= 9:
+ d.w.logNewTablePenalty = 8
+ d.state = &advancedState{}
+ d.compressionLevel = levels[level]
+ d.initDeflate()
+ d.fill = (*compressor).fillDeflate
+ d.step = (*compressor).deflateLazy
+ case -level >= MinCustomWindowSize && -level <= MaxCustomWindowSize:
+ d.w.logNewTablePenalty = 7
+ d.fast = &fastEncL5Window{maxOffset: int32(-level), cur: maxStoreBlockSize}
+ d.window = make([]byte, maxStoreBlockSize)
+ d.fill = (*compressor).fillBlock
+ d.step = (*compressor).storeFast
+ default:
+ return fmt.Errorf("flate: invalid compression level %d: want value in range [-2, 9]", level)
+ }
+ d.level = level
+ return nil
+}
+
+// reset the state of the compressor.
+func (d *compressor) reset(w io.Writer) {
+ d.w.reset(w)
+ d.sync = false
+ d.err = nil
+ // We only need to reset a few things for Snappy.
+ if d.fast != nil {
+ d.fast.Reset()
+ d.windowEnd = 0
+ d.tokens.Reset()
+ return
+ }
+ switch d.compressionLevel.chain {
+ case 0:
+ // level was NoCompression or ConstantCompression.
+ d.windowEnd = 0
+ default:
+ s := d.state
+ s.chainHead = -1
+ for i := range s.hashHead {
+ s.hashHead[i] = 0
+ }
+ for i := range s.hashPrev {
+ s.hashPrev[i] = 0
+ }
+ s.hashOffset = 1
+ s.index, d.windowEnd = 0, 0
+ d.blockStart, d.byteAvailable = 0, false
+ d.tokens.Reset()
+ s.length = minMatchLength - 1
+ s.offset = 0
+ s.ii = 0
+ s.maxInsertIndex = 0
+ }
+}
+
+func (d *compressor) close() error {
+ if d.err != nil {
+ return d.err
+ }
+ d.sync = true
+ d.step(d)
+ if d.err != nil {
+ return d.err
+ }
+ if d.w.writeStoredHeader(0, true); d.w.err != nil {
+ return d.w.err
+ }
+ d.w.flush()
+ d.w.reset(nil)
+ return d.w.err
+}
+
+// NewWriter returns a new Writer compressing data at the given level.
+// Following zlib, levels range from 1 (BestSpeed) to 9 (BestCompression);
+// higher levels typically run slower but compress more.
+// Level 0 (NoCompression) does not attempt any compression; it only adds the
+// necessary DEFLATE framing.
+// Level -1 (DefaultCompression) uses the default compression level.
+// Level -2 (ConstantCompression) will use Huffman compression only, giving
+// a very fast compression for all types of input, but sacrificing considerable
+// compression efficiency.
+//
+// If level is in the range [-2, 9] then the error returned will be nil.
+// Otherwise the error returned will be non-nil.
+func NewWriter(w io.Writer, level int) (*Writer, error) {
+ var dw Writer
+ if err := dw.d.init(w, level); err != nil {
+ return nil, err
+ }
+ return &dw, nil
+}
+
+// NewWriterDict is like NewWriter but initializes the new
+// Writer with a preset dictionary. The returned Writer behaves
+// as if the dictionary had been written to it without producing
+// any compressed output. The compressed data written to w
+// can only be decompressed by a Reader initialized with the
+// same dictionary.
+func NewWriterDict(w io.Writer, level int, dict []byte) (*Writer, error) {
+ zw, err := NewWriter(w, level)
+ if err != nil {
+ return nil, err
+ }
+ zw.d.fillWindow(dict)
+ zw.dict = append(zw.dict, dict...) // duplicate dictionary for Reset method.
+ return zw, err
+}
+
+// MinCustomWindowSize is the minimum window size that can be sent to NewWriterWindow.
+const MinCustomWindowSize = 32
+
+// MaxCustomWindowSize is the maximum custom window that can be sent to NewWriterWindow.
+const MaxCustomWindowSize = windowSize
+
+// NewWriterWindow returns a new Writer compressing data with a custom window size.
+// windowSize must be from MinCustomWindowSize to MaxCustomWindowSize.
+func NewWriterWindow(w io.Writer, windowSize int) (*Writer, error) {
+ if windowSize < MinCustomWindowSize {
+ return nil, errors.New("flate: requested window size less than MinWindowSize")
+ }
+ if windowSize > MaxCustomWindowSize {
+ return nil, errors.New("flate: requested window size bigger than MaxCustomWindowSize")
+ }
+ var dw Writer
+ if err := dw.d.init(w, -windowSize); err != nil {
+ return nil, err
+ }
+ return &dw, nil
+}
+
+// A Writer takes data written to it and writes the compressed
+// form of that data to an underlying writer (see NewWriter).
+type Writer struct {
+ d compressor
+ dict []byte
+}
+
+// Write writes data to w, which will eventually write the
+// compressed form of data to its underlying writer.
+func (w *Writer) Write(data []byte) (n int, err error) {
+ return w.d.write(data)
+}
+
+// Flush flushes any pending data to the underlying writer.
+// It is useful mainly in compressed network protocols, to ensure that
+// a remote reader has enough data to reconstruct a packet.
+// Flush does not return until the data has been written.
+// Calling Flush when there is no pending data still causes the Writer
+// to emit a sync marker of at least 4 bytes.
+// If the underlying writer returns an error, Flush returns that error.
+//
+// In the terminology of the zlib library, Flush is equivalent to Z_SYNC_FLUSH.
+func (w *Writer) Flush() error {
+ // For more about flushing:
+ // http://www.bolet.org/~pornin/deflate-flush.html
+ return w.d.syncFlush()
+}
+
+// Close flushes and closes the writer.
+func (w *Writer) Close() error {
+ return w.d.close()
+}
+
+// Reset discards the writer's state and makes it equivalent to
+// the result of NewWriter or NewWriterDict called with dst
+// and w's level and dictionary.
+func (w *Writer) Reset(dst io.Writer) {
+ if len(w.dict) > 0 {
+ // w was created with NewWriterDict
+ w.d.reset(dst)
+ if dst != nil {
+ w.d.fillWindow(w.dict)
+ }
+ } else {
+ // w was created with NewWriter
+ w.d.reset(dst)
+ }
+}
+
+// ResetDict discards the writer's state and makes it equivalent to
+// the result of NewWriter or NewWriterDict called with dst
+// and w's level, but sets a specific dictionary.
+func (w *Writer) ResetDict(dst io.Writer, dict []byte) {
+ w.dict = dict
+ w.d.reset(dst)
+ w.d.fillWindow(w.dict)
+}