mirror of
https://github.com/go-gitea/gitea
synced 2024-12-22 13:24:18 +01:00
922 lines
20 KiB
Go
Vendored
922 lines
20 KiB
Go
Vendored
// Code generated by go generate gen_inflate.go. DO NOT EDIT.
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package flate
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import (
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"bufio"
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"bytes"
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"fmt"
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"math/bits"
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"strings"
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)
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// Decode a single Huffman block from f.
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// hl and hd are the Huffman states for the lit/length values
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// and the distance values, respectively. If hd == nil, using the
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// fixed distance encoding associated with fixed Huffman blocks.
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func (f *decompressor) huffmanBytesBuffer() {
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const (
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stateInit = iota // Zero value must be stateInit
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stateDict
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)
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fr := f.r.(*bytes.Buffer)
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moreBits := func() error {
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c, err := fr.ReadByte()
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if err != nil {
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return noEOF(err)
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}
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f.roffset++
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f.b |= uint32(c) << f.nb
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f.nb += 8
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return nil
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}
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switch f.stepState {
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case stateInit:
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goto readLiteral
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case stateDict:
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goto copyHistory
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}
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readLiteral:
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// Read literal and/or (length, distance) according to RFC section 3.2.3.
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{
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var v int
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{
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// Inlined v, err := f.huffSym(f.hl)
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// Since a huffmanDecoder can be empty or be composed of a degenerate tree
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// with single element, huffSym must error on these two edge cases. In both
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// cases, the chunks slice will be 0 for the invalid sequence, leading it
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// satisfy the n == 0 check below.
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n := uint(f.hl.maxRead)
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// Optimization. Compiler isn't smart enough to keep f.b,f.nb in registers,
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// but is smart enough to keep local variables in registers, so use nb and b,
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// inline call to moreBits and reassign b,nb back to f on return.
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nb, b := f.nb, f.b
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for {
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for nb < n {
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c, err := fr.ReadByte()
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if err != nil {
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f.b = b
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f.nb = nb
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f.err = noEOF(err)
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return
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}
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f.roffset++
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b |= uint32(c) << (nb & 31)
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nb += 8
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}
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chunk := f.hl.chunks[b&(huffmanNumChunks-1)]
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n = uint(chunk & huffmanCountMask)
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if n > huffmanChunkBits {
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chunk = f.hl.links[chunk>>huffmanValueShift][(b>>huffmanChunkBits)&f.hl.linkMask]
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n = uint(chunk & huffmanCountMask)
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}
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if n <= nb {
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if n == 0 {
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f.b = b
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f.nb = nb
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if debugDecode {
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fmt.Println("huffsym: n==0")
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}
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f.err = CorruptInputError(f.roffset)
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return
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}
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f.b = b >> (n & 31)
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f.nb = nb - n
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v = int(chunk >> huffmanValueShift)
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break
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}
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}
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}
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var n uint // number of bits extra
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var length int
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var err error
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switch {
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case v < 256:
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f.dict.writeByte(byte(v))
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if f.dict.availWrite() == 0 {
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f.toRead = f.dict.readFlush()
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f.step = (*decompressor).huffmanBytesBuffer
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f.stepState = stateInit
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return
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}
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goto readLiteral
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case v == 256:
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f.finishBlock()
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return
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// otherwise, reference to older data
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case v < 265:
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length = v - (257 - 3)
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n = 0
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case v < 269:
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length = v*2 - (265*2 - 11)
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n = 1
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case v < 273:
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length = v*4 - (269*4 - 19)
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n = 2
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case v < 277:
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length = v*8 - (273*8 - 35)
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n = 3
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case v < 281:
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length = v*16 - (277*16 - 67)
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n = 4
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case v < 285:
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length = v*32 - (281*32 - 131)
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n = 5
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case v < maxNumLit:
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length = 258
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n = 0
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default:
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if debugDecode {
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fmt.Println(v, ">= maxNumLit")
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}
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f.err = CorruptInputError(f.roffset)
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return
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}
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if n > 0 {
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for f.nb < n {
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if err = moreBits(); err != nil {
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if debugDecode {
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fmt.Println("morebits n>0:", err)
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}
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f.err = err
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return
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}
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}
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length += int(f.b & uint32(1<<n-1))
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f.b >>= n
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f.nb -= n
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}
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var dist int
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if f.hd == nil {
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for f.nb < 5 {
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if err = moreBits(); err != nil {
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if debugDecode {
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fmt.Println("morebits f.nb<5:", err)
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}
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f.err = err
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return
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}
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}
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dist = int(bits.Reverse8(uint8(f.b & 0x1F << 3)))
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f.b >>= 5
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f.nb -= 5
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} else {
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if dist, err = f.huffSym(f.hd); err != nil {
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if debugDecode {
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fmt.Println("huffsym:", err)
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}
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f.err = err
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return
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}
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}
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switch {
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case dist < 4:
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dist++
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case dist < maxNumDist:
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nb := uint(dist-2) >> 1
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// have 1 bit in bottom of dist, need nb more.
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extra := (dist & 1) << nb
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for f.nb < nb {
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if err = moreBits(); err != nil {
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if debugDecode {
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fmt.Println("morebits f.nb<nb:", err)
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}
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f.err = err
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return
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}
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}
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extra |= int(f.b & uint32(1<<nb-1))
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f.b >>= nb
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f.nb -= nb
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dist = 1<<(nb+1) + 1 + extra
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default:
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if debugDecode {
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fmt.Println("dist too big:", dist, maxNumDist)
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}
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f.err = CorruptInputError(f.roffset)
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return
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}
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// No check on length; encoding can be prescient.
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if dist > f.dict.histSize() {
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if debugDecode {
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fmt.Println("dist > f.dict.histSize():", dist, f.dict.histSize())
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}
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f.err = CorruptInputError(f.roffset)
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return
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}
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f.copyLen, f.copyDist = length, dist
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goto copyHistory
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}
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copyHistory:
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// Perform a backwards copy according to RFC section 3.2.3.
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{
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cnt := f.dict.tryWriteCopy(f.copyDist, f.copyLen)
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if cnt == 0 {
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cnt = f.dict.writeCopy(f.copyDist, f.copyLen)
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}
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f.copyLen -= cnt
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if f.dict.availWrite() == 0 || f.copyLen > 0 {
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f.toRead = f.dict.readFlush()
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f.step = (*decompressor).huffmanBytesBuffer // We need to continue this work
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f.stepState = stateDict
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return
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}
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goto readLiteral
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}
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}
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|
|
|
// Decode a single Huffman block from f.
|
|
// hl and hd are the Huffman states for the lit/length values
|
|
// and the distance values, respectively. If hd == nil, using the
|
|
// fixed distance encoding associated with fixed Huffman blocks.
|
|
func (f *decompressor) huffmanBytesReader() {
|
|
const (
|
|
stateInit = iota // Zero value must be stateInit
|
|
stateDict
|
|
)
|
|
fr := f.r.(*bytes.Reader)
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moreBits := func() error {
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c, err := fr.ReadByte()
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if err != nil {
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return noEOF(err)
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}
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f.roffset++
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f.b |= uint32(c) << f.nb
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f.nb += 8
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return nil
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}
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switch f.stepState {
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case stateInit:
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goto readLiteral
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case stateDict:
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goto copyHistory
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}
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|
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|
readLiteral:
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|
// Read literal and/or (length, distance) according to RFC section 3.2.3.
|
|
{
|
|
var v int
|
|
{
|
|
// Inlined v, err := f.huffSym(f.hl)
|
|
// Since a huffmanDecoder can be empty or be composed of a degenerate tree
|
|
// with single element, huffSym must error on these two edge cases. In both
|
|
// cases, the chunks slice will be 0 for the invalid sequence, leading it
|
|
// satisfy the n == 0 check below.
|
|
n := uint(f.hl.maxRead)
|
|
// Optimization. Compiler isn't smart enough to keep f.b,f.nb in registers,
|
|
// but is smart enough to keep local variables in registers, so use nb and b,
|
|
// inline call to moreBits and reassign b,nb back to f on return.
|
|
nb, b := f.nb, f.b
|
|
for {
|
|
for nb < n {
|
|
c, err := fr.ReadByte()
|
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if err != nil {
|
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f.b = b
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f.nb = nb
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f.err = noEOF(err)
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return
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}
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f.roffset++
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b |= uint32(c) << (nb & 31)
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nb += 8
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}
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chunk := f.hl.chunks[b&(huffmanNumChunks-1)]
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n = uint(chunk & huffmanCountMask)
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if n > huffmanChunkBits {
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chunk = f.hl.links[chunk>>huffmanValueShift][(b>>huffmanChunkBits)&f.hl.linkMask]
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n = uint(chunk & huffmanCountMask)
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}
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if n <= nb {
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if n == 0 {
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f.b = b
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f.nb = nb
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if debugDecode {
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fmt.Println("huffsym: n==0")
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}
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f.err = CorruptInputError(f.roffset)
|
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return
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}
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f.b = b >> (n & 31)
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f.nb = nb - n
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v = int(chunk >> huffmanValueShift)
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break
|
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}
|
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}
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}
|
|
|
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var n uint // number of bits extra
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var length int
|
|
var err error
|
|
switch {
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case v < 256:
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f.dict.writeByte(byte(v))
|
|
if f.dict.availWrite() == 0 {
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f.toRead = f.dict.readFlush()
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f.step = (*decompressor).huffmanBytesReader
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f.stepState = stateInit
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return
|
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}
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goto readLiteral
|
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case v == 256:
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f.finishBlock()
|
|
return
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// otherwise, reference to older data
|
|
case v < 265:
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length = v - (257 - 3)
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n = 0
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case v < 269:
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length = v*2 - (265*2 - 11)
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n = 1
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|
case v < 273:
|
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length = v*4 - (269*4 - 19)
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n = 2
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case v < 277:
|
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length = v*8 - (273*8 - 35)
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n = 3
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|
case v < 281:
|
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length = v*16 - (277*16 - 67)
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n = 4
|
|
case v < 285:
|
|
length = v*32 - (281*32 - 131)
|
|
n = 5
|
|
case v < maxNumLit:
|
|
length = 258
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n = 0
|
|
default:
|
|
if debugDecode {
|
|
fmt.Println(v, ">= maxNumLit")
|
|
}
|
|
f.err = CorruptInputError(f.roffset)
|
|
return
|
|
}
|
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if n > 0 {
|
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for f.nb < n {
|
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if err = moreBits(); err != nil {
|
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if debugDecode {
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fmt.Println("morebits n>0:", err)
|
|
}
|
|
f.err = err
|
|
return
|
|
}
|
|
}
|
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length += int(f.b & uint32(1<<n-1))
|
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f.b >>= n
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f.nb -= n
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}
|
|
|
|
var dist int
|
|
if f.hd == nil {
|
|
for f.nb < 5 {
|
|
if err = moreBits(); err != nil {
|
|
if debugDecode {
|
|
fmt.Println("morebits f.nb<5:", err)
|
|
}
|
|
f.err = err
|
|
return
|
|
}
|
|
}
|
|
dist = int(bits.Reverse8(uint8(f.b & 0x1F << 3)))
|
|
f.b >>= 5
|
|
f.nb -= 5
|
|
} else {
|
|
if dist, err = f.huffSym(f.hd); err != nil {
|
|
if debugDecode {
|
|
fmt.Println("huffsym:", err)
|
|
}
|
|
f.err = err
|
|
return
|
|
}
|
|
}
|
|
|
|
switch {
|
|
case dist < 4:
|
|
dist++
|
|
case dist < maxNumDist:
|
|
nb := uint(dist-2) >> 1
|
|
// have 1 bit in bottom of dist, need nb more.
|
|
extra := (dist & 1) << nb
|
|
for f.nb < nb {
|
|
if err = moreBits(); err != nil {
|
|
if debugDecode {
|
|
fmt.Println("morebits f.nb<nb:", err)
|
|
}
|
|
f.err = err
|
|
return
|
|
}
|
|
}
|
|
extra |= int(f.b & uint32(1<<nb-1))
|
|
f.b >>= nb
|
|
f.nb -= nb
|
|
dist = 1<<(nb+1) + 1 + extra
|
|
default:
|
|
if debugDecode {
|
|
fmt.Println("dist too big:", dist, maxNumDist)
|
|
}
|
|
f.err = CorruptInputError(f.roffset)
|
|
return
|
|
}
|
|
|
|
// No check on length; encoding can be prescient.
|
|
if dist > f.dict.histSize() {
|
|
if debugDecode {
|
|
fmt.Println("dist > f.dict.histSize():", dist, f.dict.histSize())
|
|
}
|
|
f.err = CorruptInputError(f.roffset)
|
|
return
|
|
}
|
|
|
|
f.copyLen, f.copyDist = length, dist
|
|
goto copyHistory
|
|
}
|
|
|
|
copyHistory:
|
|
// Perform a backwards copy according to RFC section 3.2.3.
|
|
{
|
|
cnt := f.dict.tryWriteCopy(f.copyDist, f.copyLen)
|
|
if cnt == 0 {
|
|
cnt = f.dict.writeCopy(f.copyDist, f.copyLen)
|
|
}
|
|
f.copyLen -= cnt
|
|
|
|
if f.dict.availWrite() == 0 || f.copyLen > 0 {
|
|
f.toRead = f.dict.readFlush()
|
|
f.step = (*decompressor).huffmanBytesReader // We need to continue this work
|
|
f.stepState = stateDict
|
|
return
|
|
}
|
|
goto readLiteral
|
|
}
|
|
}
|
|
|
|
// Decode a single Huffman block from f.
|
|
// hl and hd are the Huffman states for the lit/length values
|
|
// and the distance values, respectively. If hd == nil, using the
|
|
// fixed distance encoding associated with fixed Huffman blocks.
|
|
func (f *decompressor) huffmanBufioReader() {
|
|
const (
|
|
stateInit = iota // Zero value must be stateInit
|
|
stateDict
|
|
)
|
|
fr := f.r.(*bufio.Reader)
|
|
moreBits := func() error {
|
|
c, err := fr.ReadByte()
|
|
if err != nil {
|
|
return noEOF(err)
|
|
}
|
|
f.roffset++
|
|
f.b |= uint32(c) << f.nb
|
|
f.nb += 8
|
|
return nil
|
|
}
|
|
|
|
switch f.stepState {
|
|
case stateInit:
|
|
goto readLiteral
|
|
case stateDict:
|
|
goto copyHistory
|
|
}
|
|
|
|
readLiteral:
|
|
// Read literal and/or (length, distance) according to RFC section 3.2.3.
|
|
{
|
|
var v int
|
|
{
|
|
// Inlined v, err := f.huffSym(f.hl)
|
|
// Since a huffmanDecoder can be empty or be composed of a degenerate tree
|
|
// with single element, huffSym must error on these two edge cases. In both
|
|
// cases, the chunks slice will be 0 for the invalid sequence, leading it
|
|
// satisfy the n == 0 check below.
|
|
n := uint(f.hl.maxRead)
|
|
// Optimization. Compiler isn't smart enough to keep f.b,f.nb in registers,
|
|
// but is smart enough to keep local variables in registers, so use nb and b,
|
|
// inline call to moreBits and reassign b,nb back to f on return.
|
|
nb, b := f.nb, f.b
|
|
for {
|
|
for nb < n {
|
|
c, err := fr.ReadByte()
|
|
if err != nil {
|
|
f.b = b
|
|
f.nb = nb
|
|
f.err = noEOF(err)
|
|
return
|
|
}
|
|
f.roffset++
|
|
b |= uint32(c) << (nb & 31)
|
|
nb += 8
|
|
}
|
|
chunk := f.hl.chunks[b&(huffmanNumChunks-1)]
|
|
n = uint(chunk & huffmanCountMask)
|
|
if n > huffmanChunkBits {
|
|
chunk = f.hl.links[chunk>>huffmanValueShift][(b>>huffmanChunkBits)&f.hl.linkMask]
|
|
n = uint(chunk & huffmanCountMask)
|
|
}
|
|
if n <= nb {
|
|
if n == 0 {
|
|
f.b = b
|
|
f.nb = nb
|
|
if debugDecode {
|
|
fmt.Println("huffsym: n==0")
|
|
}
|
|
f.err = CorruptInputError(f.roffset)
|
|
return
|
|
}
|
|
f.b = b >> (n & 31)
|
|
f.nb = nb - n
|
|
v = int(chunk >> huffmanValueShift)
|
|
break
|
|
}
|
|
}
|
|
}
|
|
|
|
var n uint // number of bits extra
|
|
var length int
|
|
var err error
|
|
switch {
|
|
case v < 256:
|
|
f.dict.writeByte(byte(v))
|
|
if f.dict.availWrite() == 0 {
|
|
f.toRead = f.dict.readFlush()
|
|
f.step = (*decompressor).huffmanBufioReader
|
|
f.stepState = stateInit
|
|
return
|
|
}
|
|
goto readLiteral
|
|
case v == 256:
|
|
f.finishBlock()
|
|
return
|
|
// otherwise, reference to older data
|
|
case v < 265:
|
|
length = v - (257 - 3)
|
|
n = 0
|
|
case v < 269:
|
|
length = v*2 - (265*2 - 11)
|
|
n = 1
|
|
case v < 273:
|
|
length = v*4 - (269*4 - 19)
|
|
n = 2
|
|
case v < 277:
|
|
length = v*8 - (273*8 - 35)
|
|
n = 3
|
|
case v < 281:
|
|
length = v*16 - (277*16 - 67)
|
|
n = 4
|
|
case v < 285:
|
|
length = v*32 - (281*32 - 131)
|
|
n = 5
|
|
case v < maxNumLit:
|
|
length = 258
|
|
n = 0
|
|
default:
|
|
if debugDecode {
|
|
fmt.Println(v, ">= maxNumLit")
|
|
}
|
|
f.err = CorruptInputError(f.roffset)
|
|
return
|
|
}
|
|
if n > 0 {
|
|
for f.nb < n {
|
|
if err = moreBits(); err != nil {
|
|
if debugDecode {
|
|
fmt.Println("morebits n>0:", err)
|
|
}
|
|
f.err = err
|
|
return
|
|
}
|
|
}
|
|
length += int(f.b & uint32(1<<n-1))
|
|
f.b >>= n
|
|
f.nb -= n
|
|
}
|
|
|
|
var dist int
|
|
if f.hd == nil {
|
|
for f.nb < 5 {
|
|
if err = moreBits(); err != nil {
|
|
if debugDecode {
|
|
fmt.Println("morebits f.nb<5:", err)
|
|
}
|
|
f.err = err
|
|
return
|
|
}
|
|
}
|
|
dist = int(bits.Reverse8(uint8(f.b & 0x1F << 3)))
|
|
f.b >>= 5
|
|
f.nb -= 5
|
|
} else {
|
|
if dist, err = f.huffSym(f.hd); err != nil {
|
|
if debugDecode {
|
|
fmt.Println("huffsym:", err)
|
|
}
|
|
f.err = err
|
|
return
|
|
}
|
|
}
|
|
|
|
switch {
|
|
case dist < 4:
|
|
dist++
|
|
case dist < maxNumDist:
|
|
nb := uint(dist-2) >> 1
|
|
// have 1 bit in bottom of dist, need nb more.
|
|
extra := (dist & 1) << nb
|
|
for f.nb < nb {
|
|
if err = moreBits(); err != nil {
|
|
if debugDecode {
|
|
fmt.Println("morebits f.nb<nb:", err)
|
|
}
|
|
f.err = err
|
|
return
|
|
}
|
|
}
|
|
extra |= int(f.b & uint32(1<<nb-1))
|
|
f.b >>= nb
|
|
f.nb -= nb
|
|
dist = 1<<(nb+1) + 1 + extra
|
|
default:
|
|
if debugDecode {
|
|
fmt.Println("dist too big:", dist, maxNumDist)
|
|
}
|
|
f.err = CorruptInputError(f.roffset)
|
|
return
|
|
}
|
|
|
|
// No check on length; encoding can be prescient.
|
|
if dist > f.dict.histSize() {
|
|
if debugDecode {
|
|
fmt.Println("dist > f.dict.histSize():", dist, f.dict.histSize())
|
|
}
|
|
f.err = CorruptInputError(f.roffset)
|
|
return
|
|
}
|
|
|
|
f.copyLen, f.copyDist = length, dist
|
|
goto copyHistory
|
|
}
|
|
|
|
copyHistory:
|
|
// Perform a backwards copy according to RFC section 3.2.3.
|
|
{
|
|
cnt := f.dict.tryWriteCopy(f.copyDist, f.copyLen)
|
|
if cnt == 0 {
|
|
cnt = f.dict.writeCopy(f.copyDist, f.copyLen)
|
|
}
|
|
f.copyLen -= cnt
|
|
|
|
if f.dict.availWrite() == 0 || f.copyLen > 0 {
|
|
f.toRead = f.dict.readFlush()
|
|
f.step = (*decompressor).huffmanBufioReader // We need to continue this work
|
|
f.stepState = stateDict
|
|
return
|
|
}
|
|
goto readLiteral
|
|
}
|
|
}
|
|
|
|
// Decode a single Huffman block from f.
|
|
// hl and hd are the Huffman states for the lit/length values
|
|
// and the distance values, respectively. If hd == nil, using the
|
|
// fixed distance encoding associated with fixed Huffman blocks.
|
|
func (f *decompressor) huffmanStringsReader() {
|
|
const (
|
|
stateInit = iota // Zero value must be stateInit
|
|
stateDict
|
|
)
|
|
fr := f.r.(*strings.Reader)
|
|
moreBits := func() error {
|
|
c, err := fr.ReadByte()
|
|
if err != nil {
|
|
return noEOF(err)
|
|
}
|
|
f.roffset++
|
|
f.b |= uint32(c) << f.nb
|
|
f.nb += 8
|
|
return nil
|
|
}
|
|
|
|
switch f.stepState {
|
|
case stateInit:
|
|
goto readLiteral
|
|
case stateDict:
|
|
goto copyHistory
|
|
}
|
|
|
|
readLiteral:
|
|
// Read literal and/or (length, distance) according to RFC section 3.2.3.
|
|
{
|
|
var v int
|
|
{
|
|
// Inlined v, err := f.huffSym(f.hl)
|
|
// Since a huffmanDecoder can be empty or be composed of a degenerate tree
|
|
// with single element, huffSym must error on these two edge cases. In both
|
|
// cases, the chunks slice will be 0 for the invalid sequence, leading it
|
|
// satisfy the n == 0 check below.
|
|
n := uint(f.hl.maxRead)
|
|
// Optimization. Compiler isn't smart enough to keep f.b,f.nb in registers,
|
|
// but is smart enough to keep local variables in registers, so use nb and b,
|
|
// inline call to moreBits and reassign b,nb back to f on return.
|
|
nb, b := f.nb, f.b
|
|
for {
|
|
for nb < n {
|
|
c, err := fr.ReadByte()
|
|
if err != nil {
|
|
f.b = b
|
|
f.nb = nb
|
|
f.err = noEOF(err)
|
|
return
|
|
}
|
|
f.roffset++
|
|
b |= uint32(c) << (nb & 31)
|
|
nb += 8
|
|
}
|
|
chunk := f.hl.chunks[b&(huffmanNumChunks-1)]
|
|
n = uint(chunk & huffmanCountMask)
|
|
if n > huffmanChunkBits {
|
|
chunk = f.hl.links[chunk>>huffmanValueShift][(b>>huffmanChunkBits)&f.hl.linkMask]
|
|
n = uint(chunk & huffmanCountMask)
|
|
}
|
|
if n <= nb {
|
|
if n == 0 {
|
|
f.b = b
|
|
f.nb = nb
|
|
if debugDecode {
|
|
fmt.Println("huffsym: n==0")
|
|
}
|
|
f.err = CorruptInputError(f.roffset)
|
|
return
|
|
}
|
|
f.b = b >> (n & 31)
|
|
f.nb = nb - n
|
|
v = int(chunk >> huffmanValueShift)
|
|
break
|
|
}
|
|
}
|
|
}
|
|
|
|
var n uint // number of bits extra
|
|
var length int
|
|
var err error
|
|
switch {
|
|
case v < 256:
|
|
f.dict.writeByte(byte(v))
|
|
if f.dict.availWrite() == 0 {
|
|
f.toRead = f.dict.readFlush()
|
|
f.step = (*decompressor).huffmanStringsReader
|
|
f.stepState = stateInit
|
|
return
|
|
}
|
|
goto readLiteral
|
|
case v == 256:
|
|
f.finishBlock()
|
|
return
|
|
// otherwise, reference to older data
|
|
case v < 265:
|
|
length = v - (257 - 3)
|
|
n = 0
|
|
case v < 269:
|
|
length = v*2 - (265*2 - 11)
|
|
n = 1
|
|
case v < 273:
|
|
length = v*4 - (269*4 - 19)
|
|
n = 2
|
|
case v < 277:
|
|
length = v*8 - (273*8 - 35)
|
|
n = 3
|
|
case v < 281:
|
|
length = v*16 - (277*16 - 67)
|
|
n = 4
|
|
case v < 285:
|
|
length = v*32 - (281*32 - 131)
|
|
n = 5
|
|
case v < maxNumLit:
|
|
length = 258
|
|
n = 0
|
|
default:
|
|
if debugDecode {
|
|
fmt.Println(v, ">= maxNumLit")
|
|
}
|
|
f.err = CorruptInputError(f.roffset)
|
|
return
|
|
}
|
|
if n > 0 {
|
|
for f.nb < n {
|
|
if err = moreBits(); err != nil {
|
|
if debugDecode {
|
|
fmt.Println("morebits n>0:", err)
|
|
}
|
|
f.err = err
|
|
return
|
|
}
|
|
}
|
|
length += int(f.b & uint32(1<<n-1))
|
|
f.b >>= n
|
|
f.nb -= n
|
|
}
|
|
|
|
var dist int
|
|
if f.hd == nil {
|
|
for f.nb < 5 {
|
|
if err = moreBits(); err != nil {
|
|
if debugDecode {
|
|
fmt.Println("morebits f.nb<5:", err)
|
|
}
|
|
f.err = err
|
|
return
|
|
}
|
|
}
|
|
dist = int(bits.Reverse8(uint8(f.b & 0x1F << 3)))
|
|
f.b >>= 5
|
|
f.nb -= 5
|
|
} else {
|
|
if dist, err = f.huffSym(f.hd); err != nil {
|
|
if debugDecode {
|
|
fmt.Println("huffsym:", err)
|
|
}
|
|
f.err = err
|
|
return
|
|
}
|
|
}
|
|
|
|
switch {
|
|
case dist < 4:
|
|
dist++
|
|
case dist < maxNumDist:
|
|
nb := uint(dist-2) >> 1
|
|
// have 1 bit in bottom of dist, need nb more.
|
|
extra := (dist & 1) << nb
|
|
for f.nb < nb {
|
|
if err = moreBits(); err != nil {
|
|
if debugDecode {
|
|
fmt.Println("morebits f.nb<nb:", err)
|
|
}
|
|
f.err = err
|
|
return
|
|
}
|
|
}
|
|
extra |= int(f.b & uint32(1<<nb-1))
|
|
f.b >>= nb
|
|
f.nb -= nb
|
|
dist = 1<<(nb+1) + 1 + extra
|
|
default:
|
|
if debugDecode {
|
|
fmt.Println("dist too big:", dist, maxNumDist)
|
|
}
|
|
f.err = CorruptInputError(f.roffset)
|
|
return
|
|
}
|
|
|
|
// No check on length; encoding can be prescient.
|
|
if dist > f.dict.histSize() {
|
|
if debugDecode {
|
|
fmt.Println("dist > f.dict.histSize():", dist, f.dict.histSize())
|
|
}
|
|
f.err = CorruptInputError(f.roffset)
|
|
return
|
|
}
|
|
|
|
f.copyLen, f.copyDist = length, dist
|
|
goto copyHistory
|
|
}
|
|
|
|
copyHistory:
|
|
// Perform a backwards copy according to RFC section 3.2.3.
|
|
{
|
|
cnt := f.dict.tryWriteCopy(f.copyDist, f.copyLen)
|
|
if cnt == 0 {
|
|
cnt = f.dict.writeCopy(f.copyDist, f.copyLen)
|
|
}
|
|
f.copyLen -= cnt
|
|
|
|
if f.dict.availWrite() == 0 || f.copyLen > 0 {
|
|
f.toRead = f.dict.readFlush()
|
|
f.step = (*decompressor).huffmanStringsReader // We need to continue this work
|
|
f.stepState = stateDict
|
|
return
|
|
}
|
|
goto readLiteral
|
|
}
|
|
}
|
|
|
|
func (f *decompressor) huffmanBlockDecoder() func() {
|
|
switch f.r.(type) {
|
|
case *bytes.Buffer:
|
|
return f.huffmanBytesBuffer
|
|
case *bytes.Reader:
|
|
return f.huffmanBytesReader
|
|
case *bufio.Reader:
|
|
return f.huffmanBufioReader
|
|
case *strings.Reader:
|
|
return f.huffmanStringsReader
|
|
default:
|
|
return f.huffmanBlockGeneric
|
|
}
|
|
}
|