123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287288289290291292293294295296297298299300301302303304305306307308309310311312313314315316317318319320321322323324325326327328329330331332333334335336337338339340341342343344345346347348349350351352353354355356357358359360361362363364365366367368369370371372373374375376377378379380381382383384385386387388389390391392393394395396397398399400401402403404405406407408409410411412413414415416417418419420421422423424425426427428429430431432433434435436437438439440441442443444445446447448449450451452453454455456457458459460461462463464465466467468469470471472473474475476477478479480481482483484485486487488489490491492493494495496497498499500501502503504505506507508509510511512513514515516517518519520521522523524525526527528529530531532533534535536537538539540541542543544545546547548549550551552553554555556557558559560561562563564565566567568569570571572573574575576577578579580581582583584585586587588589590591592593594595596597598599600601602603604605606607608609610611612613614615616617618619620621622623624625626627628629630631632633634635636637638639640641642643644645646647648649650651652653654655656657658659660661662663664665666667668669670671672673674675676677678679680681682683684685686687688689690691692693694695696697698699700701702703704705706707708709710711712713714715716717718719720721722723724725726727728729730731732733734735736737738739740741742743744745746747748749750751752753754755756757758759760761762763764765766767768769770771772773774775776777778779780781782783784785786787788789790791792793794795796797798799800801802803804805806807808809810811812813814815816817818819820821822823824825826827828829830831832833834835836837838839840841842843844845846847848849850851852853854855856857858859860861862863864865866867868869870871872873874875876877878879880881882883884885886887888889890891892893894895896897898899900901902903904905906907908909910911912913914915916917918919920921922923924925926927928929930931932933934935936937938939940941942943944945946947948949950951952953954955956957958959960961962963964965966967968969970971972973974975976977978979980981982983984985986987988989990991992993994995996997998999100010011002 |
- // Code generated by go generate gen_inflate.go. DO NOT EDIT.
-
- package flate
-
- import (
- "bufio"
- "bytes"
- "fmt"
- "math/bits"
- "strings"
- )
-
- // 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) huffmanBytesBuffer() {
- const (
- stateInit = iota // Zero value must be stateInit
- stateDict
- )
- fr := f.r.(*bytes.Buffer)
-
- 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 & regSizeMaskUint32)
- 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 & regSizeMaskUint32)
- f.nb = nb - n
- v = int(chunk >> huffmanValueShift)
- break
- }
- }
- }
-
- var length int
- switch {
- case v < 256:
- f.dict.writeByte(byte(v))
- if f.dict.availWrite() == 0 {
- f.toRead = f.dict.readFlush()
- f.step = (*decompressor).huffmanBytesBuffer
- f.stepState = stateInit
- return
- }
- goto readLiteral
- case v == 256:
- f.finishBlock()
- return
- // otherwise, reference to older data
- case v < 265:
- length = v - (257 - 3)
- case v < maxNumLit:
- val := decCodeToLen[(v - 257)]
- length = int(val.length) + 3
- n := uint(val.extra)
- for f.nb < n {
- c, err := fr.ReadByte()
- if err != nil {
- if debugDecode {
- fmt.Println("morebits n>0:", err)
- }
- f.err = err
- return
- }
- f.roffset++
- f.b |= uint32(c) << f.nb
- f.nb += 8
- }
- length += int(f.b & uint32(1<<(n®SizeMaskUint32)-1))
- f.b >>= n & regSizeMaskUint32
- f.nb -= n
- default:
- if debugDecode {
- fmt.Println(v, ">= maxNumLit")
- }
- f.err = CorruptInputError(f.roffset)
- return
- }
-
- var dist uint32
- if f.hd == nil {
- for f.nb < 5 {
- c, err := fr.ReadByte()
- if err != nil {
- if debugDecode {
- fmt.Println("morebits f.nb<5:", err)
- }
- f.err = err
- return
- }
- f.roffset++
- f.b |= uint32(c) << f.nb
- f.nb += 8
- }
- dist = uint32(bits.Reverse8(uint8(f.b & 0x1F << 3)))
- f.b >>= 5
- f.nb -= 5
- } else {
- // 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.hd.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 & regSizeMaskUint32)
- nb += 8
- }
- chunk := f.hd.chunks[b&(huffmanNumChunks-1)]
- n = uint(chunk & huffmanCountMask)
- if n > huffmanChunkBits {
- chunk = f.hd.links[chunk>>huffmanValueShift][(b>>huffmanChunkBits)&f.hd.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 & regSizeMaskUint32)
- f.nb = nb - n
- dist = uint32(chunk >> huffmanValueShift)
- break
- }
- }
- }
-
- 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 & regSizeMaskUint32)
- for f.nb < nb {
- c, err := fr.ReadByte()
- if err != nil {
- if debugDecode {
- fmt.Println("morebits f.nb<nb:", err)
- }
- f.err = err
- return
- }
- f.roffset++
- f.b |= uint32(c) << f.nb
- f.nb += 8
- }
- extra |= f.b & uint32(1<<(nb®SizeMaskUint32)-1)
- f.b >>= nb & regSizeMaskUint32
- f.nb -= nb
- dist = 1<<((nb+1)®SizeMaskUint32) + 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 > uint32(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, int(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).huffmanBytesBuffer // 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) huffmanBytesReader() {
- const (
- stateInit = iota // Zero value must be stateInit
- stateDict
- )
- fr := f.r.(*bytes.Reader)
-
- 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 & regSizeMaskUint32)
- 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 & regSizeMaskUint32)
- f.nb = nb - n
- v = int(chunk >> huffmanValueShift)
- break
- }
- }
- }
-
- var length int
- switch {
- case v < 256:
- f.dict.writeByte(byte(v))
- if f.dict.availWrite() == 0 {
- f.toRead = f.dict.readFlush()
- f.step = (*decompressor).huffmanBytesReader
- f.stepState = stateInit
- return
- }
- goto readLiteral
- case v == 256:
- f.finishBlock()
- return
- // otherwise, reference to older data
- case v < 265:
- length = v - (257 - 3)
- case v < maxNumLit:
- val := decCodeToLen[(v - 257)]
- length = int(val.length) + 3
- n := uint(val.extra)
- for f.nb < n {
- c, err := fr.ReadByte()
- if err != nil {
- if debugDecode {
- fmt.Println("morebits n>0:", err)
- }
- f.err = err
- return
- }
- f.roffset++
- f.b |= uint32(c) << f.nb
- f.nb += 8
- }
- length += int(f.b & uint32(1<<(n®SizeMaskUint32)-1))
- f.b >>= n & regSizeMaskUint32
- f.nb -= n
- default:
- if debugDecode {
- fmt.Println(v, ">= maxNumLit")
- }
- f.err = CorruptInputError(f.roffset)
- return
- }
-
- var dist uint32
- if f.hd == nil {
- for f.nb < 5 {
- c, err := fr.ReadByte()
- if err != nil {
- if debugDecode {
- fmt.Println("morebits f.nb<5:", err)
- }
- f.err = err
- return
- }
- f.roffset++
- f.b |= uint32(c) << f.nb
- f.nb += 8
- }
- dist = uint32(bits.Reverse8(uint8(f.b & 0x1F << 3)))
- f.b >>= 5
- f.nb -= 5
- } else {
- // 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.hd.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 & regSizeMaskUint32)
- nb += 8
- }
- chunk := f.hd.chunks[b&(huffmanNumChunks-1)]
- n = uint(chunk & huffmanCountMask)
- if n > huffmanChunkBits {
- chunk = f.hd.links[chunk>>huffmanValueShift][(b>>huffmanChunkBits)&f.hd.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 & regSizeMaskUint32)
- f.nb = nb - n
- dist = uint32(chunk >> huffmanValueShift)
- break
- }
- }
- }
-
- 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 & regSizeMaskUint32)
- for f.nb < nb {
- c, err := fr.ReadByte()
- if err != nil {
- if debugDecode {
- fmt.Println("morebits f.nb<nb:", err)
- }
- f.err = err
- return
- }
- f.roffset++
- f.b |= uint32(c) << f.nb
- f.nb += 8
- }
- extra |= f.b & uint32(1<<(nb®SizeMaskUint32)-1)
- f.b >>= nb & regSizeMaskUint32
- f.nb -= nb
- dist = 1<<((nb+1)®SizeMaskUint32) + 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 > uint32(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, int(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)
-
- 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 & regSizeMaskUint32)
- 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 & regSizeMaskUint32)
- f.nb = nb - n
- v = int(chunk >> huffmanValueShift)
- break
- }
- }
- }
-
- var length int
- 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)
- case v < maxNumLit:
- val := decCodeToLen[(v - 257)]
- length = int(val.length) + 3
- n := uint(val.extra)
- for f.nb < n {
- c, err := fr.ReadByte()
- if err != nil {
- if debugDecode {
- fmt.Println("morebits n>0:", err)
- }
- f.err = err
- return
- }
- f.roffset++
- f.b |= uint32(c) << f.nb
- f.nb += 8
- }
- length += int(f.b & uint32(1<<(n®SizeMaskUint32)-1))
- f.b >>= n & regSizeMaskUint32
- f.nb -= n
- default:
- if debugDecode {
- fmt.Println(v, ">= maxNumLit")
- }
- f.err = CorruptInputError(f.roffset)
- return
- }
-
- var dist uint32
- if f.hd == nil {
- for f.nb < 5 {
- c, err := fr.ReadByte()
- if err != nil {
- if debugDecode {
- fmt.Println("morebits f.nb<5:", err)
- }
- f.err = err
- return
- }
- f.roffset++
- f.b |= uint32(c) << f.nb
- f.nb += 8
- }
- dist = uint32(bits.Reverse8(uint8(f.b & 0x1F << 3)))
- f.b >>= 5
- f.nb -= 5
- } else {
- // 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.hd.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 & regSizeMaskUint32)
- nb += 8
- }
- chunk := f.hd.chunks[b&(huffmanNumChunks-1)]
- n = uint(chunk & huffmanCountMask)
- if n > huffmanChunkBits {
- chunk = f.hd.links[chunk>>huffmanValueShift][(b>>huffmanChunkBits)&f.hd.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 & regSizeMaskUint32)
- f.nb = nb - n
- dist = uint32(chunk >> huffmanValueShift)
- break
- }
- }
- }
-
- 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 & regSizeMaskUint32)
- for f.nb < nb {
- c, err := fr.ReadByte()
- if err != nil {
- if debugDecode {
- fmt.Println("morebits f.nb<nb:", err)
- }
- f.err = err
- return
- }
- f.roffset++
- f.b |= uint32(c) << f.nb
- f.nb += 8
- }
- extra |= f.b & uint32(1<<(nb®SizeMaskUint32)-1)
- f.b >>= nb & regSizeMaskUint32
- f.nb -= nb
- dist = 1<<((nb+1)®SizeMaskUint32) + 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 > uint32(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, int(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)
-
- 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 & regSizeMaskUint32)
- 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 & regSizeMaskUint32)
- f.nb = nb - n
- v = int(chunk >> huffmanValueShift)
- break
- }
- }
- }
-
- var length int
- 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)
- case v < maxNumLit:
- val := decCodeToLen[(v - 257)]
- length = int(val.length) + 3
- n := uint(val.extra)
- for f.nb < n {
- c, err := fr.ReadByte()
- if err != nil {
- if debugDecode {
- fmt.Println("morebits n>0:", err)
- }
- f.err = err
- return
- }
- f.roffset++
- f.b |= uint32(c) << f.nb
- f.nb += 8
- }
- length += int(f.b & uint32(1<<(n®SizeMaskUint32)-1))
- f.b >>= n & regSizeMaskUint32
- f.nb -= n
- default:
- if debugDecode {
- fmt.Println(v, ">= maxNumLit")
- }
- f.err = CorruptInputError(f.roffset)
- return
- }
-
- var dist uint32
- if f.hd == nil {
- for f.nb < 5 {
- c, err := fr.ReadByte()
- if err != nil {
- if debugDecode {
- fmt.Println("morebits f.nb<5:", err)
- }
- f.err = err
- return
- }
- f.roffset++
- f.b |= uint32(c) << f.nb
- f.nb += 8
- }
- dist = uint32(bits.Reverse8(uint8(f.b & 0x1F << 3)))
- f.b >>= 5
- f.nb -= 5
- } else {
- // 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.hd.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 & regSizeMaskUint32)
- nb += 8
- }
- chunk := f.hd.chunks[b&(huffmanNumChunks-1)]
- n = uint(chunk & huffmanCountMask)
- if n > huffmanChunkBits {
- chunk = f.hd.links[chunk>>huffmanValueShift][(b>>huffmanChunkBits)&f.hd.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 & regSizeMaskUint32)
- f.nb = nb - n
- dist = uint32(chunk >> huffmanValueShift)
- break
- }
- }
- }
-
- 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 & regSizeMaskUint32)
- for f.nb < nb {
- c, err := fr.ReadByte()
- if err != nil {
- if debugDecode {
- fmt.Println("morebits f.nb<nb:", err)
- }
- f.err = err
- return
- }
- f.roffset++
- f.b |= uint32(c) << f.nb
- f.nb += 8
- }
- extra |= f.b & uint32(1<<(nb®SizeMaskUint32)-1)
- f.b >>= nb & regSizeMaskUint32
- f.nb -= nb
- dist = 1<<((nb+1)®SizeMaskUint32) + 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 > uint32(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, int(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
- }
- }
|