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path: root/vendor/github.com/klauspost/compress/flate/inflate.go
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Diffstat (limited to 'vendor/github.com/klauspost/compress/flate/inflate.go')
-rw-r--r--vendor/github.com/klauspost/compress/flate/inflate.go222
1 files changed, 7 insertions, 215 deletions
diff --git a/vendor/github.com/klauspost/compress/flate/inflate.go b/vendor/github.com/klauspost/compress/flate/inflate.go
index d5f62f6a2..414c0bea9 100644
--- a/vendor/github.com/klauspost/compress/flate/inflate.go
+++ b/vendor/github.com/klauspost/compress/flate/inflate.go
@@ -36,6 +36,13 @@ type lengthExtra struct {
var decCodeToLen = [32]lengthExtra{{length: 0x0, extra: 0x0}, {length: 0x1, extra: 0x0}, {length: 0x2, extra: 0x0}, {length: 0x3, extra: 0x0}, {length: 0x4, extra: 0x0}, {length: 0x5, extra: 0x0}, {length: 0x6, extra: 0x0}, {length: 0x7, extra: 0x0}, {length: 0x8, extra: 0x1}, {length: 0xa, extra: 0x1}, {length: 0xc, extra: 0x1}, {length: 0xe, extra: 0x1}, {length: 0x10, extra: 0x2}, {length: 0x14, extra: 0x2}, {length: 0x18, extra: 0x2}, {length: 0x1c, extra: 0x2}, {length: 0x20, extra: 0x3}, {length: 0x28, extra: 0x3}, {length: 0x30, extra: 0x3}, {length: 0x38, extra: 0x3}, {length: 0x40, extra: 0x4}, {length: 0x50, extra: 0x4}, {length: 0x60, extra: 0x4}, {length: 0x70, extra: 0x4}, {length: 0x80, extra: 0x5}, {length: 0xa0, extra: 0x5}, {length: 0xc0, extra: 0x5}, {length: 0xe0, extra: 0x5}, {length: 0xff, extra: 0x0}, {length: 0x0, extra: 0x0}, {length: 0x0, extra: 0x0}, {length: 0x0, extra: 0x0}}
+var bitMask32 = [32]uint32{
+ 0, 1, 3, 7, 0xF, 0x1F, 0x3F, 0x7F, 0xFF,
+ 0x1FF, 0x3FF, 0x7FF, 0xFFF, 0x1FFF, 0x3FFF, 0x7FFF, 0xFFFF,
+ 0x1ffff, 0x3ffff, 0x7FFFF, 0xfFFFF, 0x1fFFFF, 0x3fFFFF, 0x7fFFFF, 0xffFFFF,
+ 0x1ffFFFF, 0x3ffFFFF, 0x7ffFFFF, 0xfffFFFF, 0x1fffFFFF, 0x3fffFFFF, 0x7fffFFFF,
+} // up to 32 bits
+
// Initialize the fixedHuffmanDecoder only once upon first use.
var fixedOnce sync.Once
var fixedHuffmanDecoder huffmanDecoder
@@ -559,221 +566,6 @@ func (f *decompressor) readHuffman() error {
return nil
}
-// 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) huffmanBlockGeneric() {
- const (
- stateInit = iota // Zero value must be stateInit
- stateDict
- )
-
- 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 := f.r.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 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).huffmanBlockGeneric
- 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 = f.moreBits(); err != nil {
- if debugDecode {
- fmt.Println("morebits n>0:", err)
- }
- f.err = err
- return
- }
- }
- length += int(f.b & uint32(1<<(n&regSizeMaskUint32)-1))
- f.b >>= n & regSizeMaskUint32
- f.nb -= n
- }
-
- var dist uint32
- if f.hd == nil {
- for f.nb < 5 {
- if err = f.moreBits(); err != nil {
- if debugDecode {
- fmt.Println("morebits f.nb<5:", err)
- }
- f.err = err
- return
- }
- }
- dist = uint32(bits.Reverse8(uint8(f.b & 0x1F << 3)))
- f.b >>= 5
- f.nb -= 5
- } else {
- sym, err := f.huffSym(f.hd)
- if err != nil {
- if debugDecode {
- fmt.Println("huffsym:", err)
- }
- f.err = err
- return
- }
- dist = uint32(sym)
- }
-
- 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 {
- if err = f.moreBits(); err != nil {
- if debugDecode {
- fmt.Println("morebits f.nb<nb:", err)
- }
- f.err = err
- return
- }
- }
- extra |= f.b & uint32(1<<(nb&regSizeMaskUint32)-1)
- f.b >>= nb & regSizeMaskUint32
- f.nb -= nb
- dist = 1<<((nb+1)&regSizeMaskUint32) + 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).huffmanBlockGeneric // We need to continue this work
- f.stepState = stateDict
- return
- }
- goto readLiteral
- }
-}
-
// Copy a single uncompressed data block from input to output.
func (f *decompressor) dataBlock() {
// Uncompressed.
generated by cgit v1.2.3-54-g00ecf (git 2.39.0) at 2024-10-01 16:31:06 +0000