Co-authored-by: zeripath <art27@cantab.net>for-closed-social
@ -0,0 +1,24 @@ | |||
kind: pipeline | |||
name: go1-1-2 | |||
steps: | |||
- name: test | |||
image: golang:1.12 | |||
environment: | |||
GOPROXY: https://goproxy.cn | |||
commands: | |||
- go build -v | |||
- go test -v -race -coverprofile=coverage.txt -covermode=atomic | |||
--- | |||
kind: pipeline | |||
name: go1-1-3 | |||
steps: | |||
- name: test | |||
image: golang:1.13 | |||
environment: | |||
GOPROXY: https://goproxy.cn | |||
commands: | |||
- go build -v | |||
- go test -v -race -coverprofile=coverage.txt -covermode=atomic |
@ -0,0 +1,19 @@ | |||
# gzip | |||
Middleware gzip provides gzip comparess middleware for [Macaron](https://gitea.com/macaron/macaron). | |||
### Installation | |||
go get gitea.com/macaron/gzip | |||
## Getting Help | |||
- [API Reference](https://godoc.org/gitea.com/macaron/gzip) | |||
## Credits | |||
This package is a modified version of [go-macaron gzip](github.com/go-macaron/gzip). | |||
## License | |||
This project is under the Apache License, Version 2.0. See the [LICENSE](LICENSE) file for the full license text. |
@ -0,0 +1,274 @@ | |||
// +build generate | |||
//go:generate go run $GOFILE && gofmt -w inflate_gen.go | |||
package main | |||
import ( | |||
"os" | |||
"strings" | |||
) | |||
func main() { | |||
f, err := os.Create("inflate_gen.go") | |||
if err != nil { | |||
panic(err) | |||
} | |||
defer f.Close() | |||
types := []string{"*bytes.Buffer", "*bytes.Reader", "*bufio.Reader", "*strings.Reader"} | |||
names := []string{"BytesBuffer", "BytesReader", "BufioReader", "StringsReader"} | |||
imports := []string{"bytes", "bufio", "io", "strings", "math/bits"} | |||
f.WriteString(`// Code generated by go generate gen_inflate.go. DO NOT EDIT. | |||
package flate | |||
import ( | |||
`) | |||
for _, imp := range imports { | |||
f.WriteString("\t\"" + imp + "\"\n") | |||
} | |||
f.WriteString(")\n\n") | |||
template := ` | |||
// 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) $FUNCNAME$() { | |||
const ( | |||
stateInit = iota // Zero value must be stateInit | |||
stateDict | |||
) | |||
fr := f.r.($TYPE$) | |||
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).$FUNCNAME$ | |||
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).$FUNCNAME$ // We need to continue this work | |||
f.stepState = stateDict | |||
return | |||
} | |||
goto readLiteral | |||
} | |||
} | |||
` | |||
for i, t := range types { | |||
s := strings.Replace(template, "$FUNCNAME$", "huffman"+names[i], -1) | |||
s = strings.Replace(s, "$TYPE$", t, -1) | |||
f.WriteString(s) | |||
} | |||
f.WriteString("func (f *decompressor) huffmanBlockDecoder() func() {\n") | |||
f.WriteString("\tswitch f.r.(type) {\n") | |||
for i, t := range types { | |||
f.WriteString("\t\tcase " + t + ":\n") | |||
f.WriteString("\t\t\treturn f.huffman" + names[i] + "\n") | |||
} | |||
f.WriteString("\t\tdefault:\n") | |||
f.WriteString("\t\t\treturn f.huffmanBlockGeneric") | |||
f.WriteString("\t}\n}\n") | |||
} |
@ -0,0 +1,178 @@ | |||
// Copyright 2009 The Go Authors. All rights reserved. | |||
// Use of this source code is governed by a BSD-style | |||
// license that can be found in the LICENSE file. | |||
package flate | |||
// Sort sorts data. | |||
// It makes one call to data.Len to determine n, and O(n*log(n)) calls to | |||
// data.Less and data.Swap. The sort is not guaranteed to be stable. | |||
func sortByFreq(data []literalNode) { | |||
n := len(data) | |||
quickSortByFreq(data, 0, n, maxDepth(n)) | |||
} | |||
func quickSortByFreq(data []literalNode, a, b, maxDepth int) { | |||
for b-a > 12 { // Use ShellSort for slices <= 12 elements | |||
if maxDepth == 0 { | |||
heapSort(data, a, b) | |||
return | |||
} | |||
maxDepth-- | |||
mlo, mhi := doPivotByFreq(data, a, b) | |||
// Avoiding recursion on the larger subproblem guarantees | |||
// a stack depth of at most lg(b-a). | |||
if mlo-a < b-mhi { | |||
quickSortByFreq(data, a, mlo, maxDepth) | |||
a = mhi // i.e., quickSortByFreq(data, mhi, b) | |||
} else { | |||
quickSortByFreq(data, mhi, b, maxDepth) | |||
b = mlo // i.e., quickSortByFreq(data, a, mlo) | |||
} | |||
} | |||
if b-a > 1 { | |||
// Do ShellSort pass with gap 6 | |||
// It could be written in this simplified form cause b-a <= 12 | |||
for i := a + 6; i < b; i++ { | |||
if data[i].freq == data[i-6].freq && data[i].literal < data[i-6].literal || data[i].freq < data[i-6].freq { | |||
data[i], data[i-6] = data[i-6], data[i] | |||
} | |||
} | |||
insertionSortByFreq(data, a, b) | |||
} | |||
} | |||
// siftDownByFreq implements the heap property on data[lo, hi). | |||
// first is an offset into the array where the root of the heap lies. | |||
func siftDownByFreq(data []literalNode, lo, hi, first int) { | |||
root := lo | |||
for { | |||
child := 2*root + 1 | |||
if child >= hi { | |||
break | |||
} | |||
if child+1 < hi && (data[first+child].freq == data[first+child+1].freq && data[first+child].literal < data[first+child+1].literal || data[first+child].freq < data[first+child+1].freq) { | |||
child++ | |||
} | |||
if data[first+root].freq == data[first+child].freq && data[first+root].literal > data[first+child].literal || data[first+root].freq > data[first+child].freq { | |||
return | |||
} | |||
data[first+root], data[first+child] = data[first+child], data[first+root] | |||
root = child | |||
} | |||
} | |||
func doPivotByFreq(data []literalNode, lo, hi int) (midlo, midhi int) { | |||
m := int(uint(lo+hi) >> 1) // Written like this to avoid integer overflow. | |||
if hi-lo > 40 { | |||
// Tukey's ``Ninther,'' median of three medians of three. | |||
s := (hi - lo) / 8 | |||
medianOfThreeSortByFreq(data, lo, lo+s, lo+2*s) | |||
medianOfThreeSortByFreq(data, m, m-s, m+s) | |||
medianOfThreeSortByFreq(data, hi-1, hi-1-s, hi-1-2*s) | |||
} | |||
medianOfThreeSortByFreq(data, lo, m, hi-1) | |||
// Invariants are: | |||
// data[lo] = pivot (set up by ChoosePivot) | |||
// data[lo < i < a] < pivot | |||
// data[a <= i < b] <= pivot | |||
// data[b <= i < c] unexamined | |||
// data[c <= i < hi-1] > pivot | |||
// data[hi-1] >= pivot | |||
pivot := lo | |||
a, c := lo+1, hi-1 | |||
for ; a < c && (data[a].freq == data[pivot].freq && data[a].literal < data[pivot].literal || data[a].freq < data[pivot].freq); a++ { | |||
} | |||
b := a | |||
for { | |||
for ; b < c && (data[pivot].freq == data[b].freq && data[pivot].literal > data[b].literal || data[pivot].freq > data[b].freq); b++ { // data[b] <= pivot | |||
} | |||
for ; b < c && (data[pivot].freq == data[c-1].freq && data[pivot].literal < data[c-1].literal || data[pivot].freq < data[c-1].freq); c-- { // data[c-1] > pivot | |||
} | |||
if b >= c { | |||
break | |||
} | |||
// data[b] > pivot; data[c-1] <= pivot | |||
data[b], data[c-1] = data[c-1], data[b] | |||
b++ | |||
c-- | |||
} | |||
// If hi-c<3 then there are duplicates (by property of median of nine). | |||
// Let's be a bit more conservative, and set border to 5. | |||
protect := hi-c < 5 | |||
if !protect && hi-c < (hi-lo)/4 { | |||
// Lets test some points for equality to pivot | |||
dups := 0 | |||
if data[pivot].freq == data[hi-1].freq && data[pivot].literal > data[hi-1].literal || data[pivot].freq > data[hi-1].freq { // data[hi-1] = pivot | |||
data[c], data[hi-1] = data[hi-1], data[c] | |||
c++ | |||
dups++ | |||
} | |||
if data[b-1].freq == data[pivot].freq && data[b-1].literal > data[pivot].literal || data[b-1].freq > data[pivot].freq { // data[b-1] = pivot | |||
b-- | |||
dups++ | |||
} | |||
// m-lo = (hi-lo)/2 > 6 | |||
// b-lo > (hi-lo)*3/4-1 > 8 | |||
// ==> m < b ==> data[m] <= pivot | |||
if data[m].freq == data[pivot].freq && data[m].literal > data[pivot].literal || data[m].freq > data[pivot].freq { // data[m] = pivot | |||
data[m], data[b-1] = data[b-1], data[m] | |||
b-- | |||
dups++ | |||
} | |||
// if at least 2 points are equal to pivot, assume skewed distribution | |||
protect = dups > 1 | |||
} | |||
if protect { | |||
// Protect against a lot of duplicates | |||
// Add invariant: | |||
// data[a <= i < b] unexamined | |||
// data[b <= i < c] = pivot | |||
for { | |||
for ; a < b && (data[b-1].freq == data[pivot].freq && data[b-1].literal > data[pivot].literal || data[b-1].freq > data[pivot].freq); b-- { // data[b] == pivot | |||
} | |||
for ; a < b && (data[a].freq == data[pivot].freq && data[a].literal < data[pivot].literal || data[a].freq < data[pivot].freq); a++ { // data[a] < pivot | |||
} | |||
if a >= b { | |||
break | |||
} | |||
// data[a] == pivot; data[b-1] < pivot | |||
data[a], data[b-1] = data[b-1], data[a] | |||
a++ | |||
b-- | |||
} | |||
} | |||
// Swap pivot into middle | |||
data[pivot], data[b-1] = data[b-1], data[pivot] | |||
return b - 1, c | |||
} | |||
// Insertion sort | |||
func insertionSortByFreq(data []literalNode, a, b int) { | |||
for i := a + 1; i < b; i++ { | |||
for j := i; j > a && (data[j].freq == data[j-1].freq && data[j].literal < data[j-1].literal || data[j].freq < data[j-1].freq); j-- { | |||
data[j], data[j-1] = data[j-1], data[j] | |||
} | |||
} | |||
} | |||
// quickSortByFreq, loosely following Bentley and McIlroy, | |||
// ``Engineering a Sort Function,'' SP&E November 1993. | |||
// medianOfThreeSortByFreq moves the median of the three values data[m0], data[m1], data[m2] into data[m1]. | |||
func medianOfThreeSortByFreq(data []literalNode, m1, m0, m2 int) { | |||
// sort 3 elements | |||
if data[m1].freq == data[m0].freq && data[m1].literal < data[m0].literal || data[m1].freq < data[m0].freq { | |||
data[m1], data[m0] = data[m0], data[m1] | |||
} | |||
// data[m0] <= data[m1] | |||
if data[m2].freq == data[m1].freq && data[m2].literal < data[m1].literal || data[m2].freq < data[m1].freq { | |||
data[m2], data[m1] = data[m1], data[m2] | |||
// data[m0] <= data[m2] && data[m1] < data[m2] | |||
if data[m1].freq == data[m0].freq && data[m1].literal < data[m0].literal || data[m1].freq < data[m0].freq { | |||
data[m1], data[m0] = data[m0], data[m1] | |||
} | |||
} | |||
// now data[m0] <= data[m1] <= data[m2] | |||
} |
@ -0,0 +1,201 @@ | |||
// Copyright 2009 The Go Authors. All rights reserved. | |||
// Use of this source code is governed by a BSD-style | |||
// license that can be found in the LICENSE file. | |||
package flate | |||
// Sort sorts data. | |||
// It makes one call to data.Len to determine n, and O(n*log(n)) calls to | |||
// data.Less and data.Swap. The sort is not guaranteed to be stable. | |||
func sortByLiteral(data []literalNode) { | |||
n := len(data) | |||
quickSort(data, 0, n, maxDepth(n)) | |||
} | |||
func quickSort(data []literalNode, a, b, maxDepth int) { | |||
for b-a > 12 { // Use ShellSort for slices <= 12 elements | |||
if maxDepth == 0 { | |||
heapSort(data, a, b) | |||
return | |||
} | |||
maxDepth-- | |||
mlo, mhi := doPivot(data, a, b) | |||
// Avoiding recursion on the larger subproblem guarantees | |||
// a stack depth of at most lg(b-a). | |||
if mlo-a < b-mhi { | |||
quickSort(data, a, mlo, maxDepth) | |||
a = mhi // i.e., quickSort(data, mhi, b) | |||
} else { | |||
quickSort(data, mhi, b, maxDepth) | |||
b = mlo // i.e., quickSort(data, a, mlo) | |||
} | |||
} | |||
if b-a > 1 { | |||
// Do ShellSort pass with gap 6 | |||
// It could be written in this simplified form cause b-a <= 12 | |||
for i := a + 6; i < b; i++ { | |||
if data[i].literal < data[i-6].literal { | |||
data[i], data[i-6] = data[i-6], data[i] | |||
} | |||
} | |||
insertionSort(data, a, b) | |||
} | |||
} | |||
func heapSort(data []literalNode, a, b int) { | |||
first := a | |||
lo := 0 | |||
hi := b - a | |||
// Build heap with greatest element at top. | |||
for i := (hi - 1) / 2; i >= 0; i-- { | |||
siftDown(data, i, hi, first) | |||
} | |||
// Pop elements, largest first, into end of data. | |||
for i := hi - 1; i >= 0; i-- { | |||
data[first], data[first+i] = data[first+i], data[first] | |||
siftDown(data, lo, i, first) | |||
} | |||
} | |||
// siftDown implements the heap property on data[lo, hi). | |||
// first is an offset into the array where the root of the heap lies. | |||
func siftDown(data []literalNode, lo, hi, first int) { | |||
root := lo | |||
for { | |||
child := 2*root + 1 | |||
if child >= hi { | |||
break | |||
} | |||
if child+1 < hi && data[first+child].literal < data[first+child+1].literal { | |||
child++ | |||
} | |||
if data[first+root].literal > data[first+child].literal { | |||
return | |||
} | |||
data[first+root], data[first+child] = data[first+child], data[first+root] | |||
root = child | |||
} | |||
} | |||
func doPivot(data []literalNode, lo, hi int) (midlo, midhi int) { | |||
m := int(uint(lo+hi) >> 1) // Written like this to avoid integer overflow. | |||
if hi-lo > 40 { | |||
// Tukey's ``Ninther,'' median of three medians of three. | |||
s := (hi - lo) / 8 | |||
medianOfThree(data, lo, lo+s, lo+2*s) | |||
medianOfThree(data, m, m-s, m+s) | |||
medianOfThree(data, hi-1, hi-1-s, hi-1-2*s) | |||
} | |||
medianOfThree(data, lo, m, hi-1) | |||
// Invariants are: | |||
// data[lo] = pivot (set up by ChoosePivot) | |||
// data[lo < i < a] < pivot | |||
// data[a <= i < b] <= pivot | |||
// data[b <= i < c] unexamined | |||
// data[c <= i < hi-1] > pivot | |||
// data[hi-1] >= pivot | |||
pivot := lo | |||
a, c := lo+1, hi-1 | |||
for ; a < c && data[a].literal < data[pivot].literal; a++ { | |||
} | |||
b := a | |||
for { | |||
for ; b < c && data[pivot].literal > data[b].literal; b++ { // data[b] <= pivot | |||
} | |||
for ; b < c && data[pivot].literal < data[c-1].literal; c-- { // data[c-1] > pivot | |||
} | |||
if b >= c { | |||
break | |||
} | |||
// data[b] > pivot; data[c-1] <= pivot | |||
data[b], data[c-1] = data[c-1], data[b] | |||
b++ | |||
c-- | |||
} | |||
// If hi-c<3 then there are duplicates (by property of median of nine). | |||
// Let's be a bit more conservative, and set border to 5. | |||
protect := hi-c < 5 | |||
if !protect && hi-c < (hi-lo)/4 { | |||
// Lets test some points for equality to pivot | |||
dups := 0 | |||
if data[pivot].literal > data[hi-1].literal { // data[hi-1] = pivot | |||
data[c], data[hi-1] = data[hi-1], data[c] | |||
c++ | |||
dups++ | |||
} | |||
if data[b-1].literal > data[pivot].literal { // data[b-1] = pivot | |||
b-- | |||
dups++ | |||
} | |||
// m-lo = (hi-lo)/2 > 6 | |||
// b-lo > (hi-lo)*3/4-1 > 8 | |||
// ==> m < b ==> data[m] <= pivot | |||
if data[m].literal > data[pivot].literal { // data[m] = pivot | |||
data[m], data[b-1] = data[b-1], data[m] | |||
b-- | |||
dups++ | |||
} | |||
// if at least 2 points are equal to pivot, assume skewed distribution | |||
protect = dups > 1 | |||
} | |||
if protect { | |||
// Protect against a lot of duplicates | |||
// Add invariant: | |||
// data[a <= i < b] unexamined | |||
// data[b <= i < c] = pivot | |||
for { | |||
for ; a < b && data[b-1].literal > data[pivot].literal; b-- { // data[b] == pivot | |||
} | |||
for ; a < b && data[a].literal < data[pivot].literal; a++ { // data[a] < pivot | |||
} | |||
if a >= b { | |||
break | |||
} | |||
// data[a] == pivot; data[b-1] < pivot | |||
data[a], data[b-1] = data[b-1], data[a] | |||
a++ | |||
b-- | |||
} | |||
} | |||
// Swap pivot into middle | |||
data[pivot], data[b-1] = data[b-1], data[pivot] | |||
return b - 1, c | |||
} | |||
// Insertion sort | |||
func insertionSort(data []literalNode, a, b int) { | |||
for i := a + 1; i < b; i++ { | |||
for j := i; j > a && data[j].literal < data[j-1].literal; j-- { | |||
data[j], data[j-1] = data[j-1], data[j] | |||
} | |||
} | |||
} | |||
// maxDepth returns a threshold at which quicksort should switch | |||
// to heapsort. It returns 2*ceil(lg(n+1)). | |||
func maxDepth(n int) int { | |||
var depth int | |||
for i := n; i > 0; i >>= 1 { | |||
depth++ | |||
} | |||
return depth * 2 | |||
} | |||
// medianOfThree moves the median of the three values data[m0], data[m1], data[m2] into data[m1]. | |||
func medianOfThree(data []literalNode, m1, m0, m2 int) { | |||
// sort 3 elements | |||
if data[m1].literal < data[m0].literal { | |||
data[m1], data[m0] = data[m0], data[m1] | |||
} | |||
// data[m0] <= data[m1] | |||
if data[m2].literal < data[m1].literal { | |||
data[m2], data[m1] = data[m1], data[m2] | |||
// data[m0] <= data[m2] && data[m1] < data[m2] | |||
if data[m1].literal < data[m0].literal { | |||
data[m1], data[m0] = data[m0], data[m1] | |||
} | |||
} | |||
// now data[m0] <= data[m1] <= data[m2] | |||
} |
@ -0,0 +1,922 @@ | |||
// 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) | |||
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).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) | |||
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).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) | |||
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).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) | |||
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).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 | |||
} | |||
} |