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forgejo/vendor/github.com/nwaples/rardecode/decode29_lz.go
PhilippHomann 684b7a999f
Dump: add output format tar and output to stdout (#10376)
* Dump: Use mholt/archive/v3 to support tar including many compressions

Signed-off-by: Philipp Homann <homann.philipp@googlemail.com>

* Dump: Allow dump output to stdout

Signed-off-by: Philipp Homann <homann.philipp@googlemail.com>

* Dump: Fixed bug present since #6677 where SessionConfig.Provider is never "file"

Signed-off-by: Philipp Homann <homann.philipp@googlemail.com>

* Dump: never pack RepoRootPath, LFS.ContentPath and LogRootPath when they are below AppDataPath

Signed-off-by: Philipp Homann <homann.philipp@googlemail.com>

* Dump: also dump LFS (fixes #10058)

Signed-off-by: Philipp Homann <homann.philipp@googlemail.com>

* Dump: never dump CustomPath if CustomPath is a subdir of or equal to AppDataPath (fixes #10365)

Signed-off-by: Philipp Homann <homann.philipp@googlemail.com>

* Use log.Info instead of fmt.Fprintf

Signed-off-by: Philipp Homann <homann.philipp@googlemail.com>

* import ordering

* make fmt

Co-authored-by: zeripath <art27@cantab.net>
Co-authored-by: techknowlogick <techknowlogick@gitea.io>
Co-authored-by: Matti R <matti@mdranta.net>
2020-06-05 16:47:39 -04:00

247 lines
5 KiB
Go
Vendored

package rardecode
const (
mainSize = 299
offsetSize = 60
lowOffsetSize = 17
lengthSize = 28
tableSize = mainSize + offsetSize + lowOffsetSize + lengthSize
)
var (
lengthBase = [28]int{0, 1, 2, 3, 4, 5, 6, 7, 8, 10, 12, 14, 16, 20,
24, 28, 32, 40, 48, 56, 64, 80, 96, 112, 128, 160, 192, 224}
lengthExtraBits = [28]uint{0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2,
2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5}
offsetBase = [60]int{0, 1, 2, 3, 4, 6, 8, 12, 16, 24, 32, 48, 64, 96,
128, 192, 256, 384, 512, 768, 1024, 1536, 2048, 3072, 4096,
6144, 8192, 12288, 16384, 24576, 32768, 49152, 65536, 98304,
131072, 196608, 262144, 327680, 393216, 458752, 524288,
589824, 655360, 720896, 786432, 851968, 917504, 983040,
1048576, 1310720, 1572864, 1835008, 2097152, 2359296, 2621440,
2883584, 3145728, 3407872, 3670016, 3932160}
offsetExtraBits = [60]uint{0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6,
6, 7, 7, 8, 8, 9, 9, 10, 10, 11, 11, 12, 12, 13, 13, 14, 14,
15, 15, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16,
18, 18, 18, 18, 18, 18, 18, 18, 18, 18, 18, 18}
shortOffsetBase = [8]int{0, 4, 8, 16, 32, 64, 128, 192}
shortOffsetExtraBits = [8]uint{2, 2, 3, 4, 5, 6, 6, 6}
)
type lz29Decoder struct {
codeLength [tableSize]byte
mainDecoder huffmanDecoder
offsetDecoder huffmanDecoder
lowOffsetDecoder huffmanDecoder
lengthDecoder huffmanDecoder
offset [4]int // history of previous offsets
length int // previous length
lowOffset int
lowOffsetRepeats int
br *rarBitReader
}
func (d *lz29Decoder) reset() {
for i := range d.offset {
d.offset[i] = 0
}
d.length = 0
for i := range d.codeLength {
d.codeLength[i] = 0
}
}
func (d *lz29Decoder) init(br *rarBitReader) error {
d.br = br
d.lowOffset = 0
d.lowOffsetRepeats = 0
n, err := d.br.readBits(1)
if err != nil {
return err
}
addOld := n > 0
cl := d.codeLength[:]
if err = readCodeLengthTable(d.br, cl, addOld); err != nil {
return err
}
d.mainDecoder.init(cl[:mainSize])
cl = cl[mainSize:]
d.offsetDecoder.init(cl[:offsetSize])
cl = cl[offsetSize:]
d.lowOffsetDecoder.init(cl[:lowOffsetSize])
cl = cl[lowOffsetSize:]
d.lengthDecoder.init(cl)
return nil
}
func (d *lz29Decoder) readFilterData() (b []byte, err error) {
flags, err := d.br.ReadByte()
if err != nil {
return nil, err
}
n := (int(flags) & 7) + 1
switch n {
case 7:
n, err = d.br.readBits(8)
n += 7
if err != nil {
return nil, err
}
case 8:
n, err = d.br.readBits(16)
if err != nil {
return nil, err
}
}
buf := make([]byte, n+1)
buf[0] = flags
err = d.br.readFull(buf[1:])
return buf, err
}
func (d *lz29Decoder) readEndOfBlock() error {
n, err := d.br.readBits(1)
if err != nil {
return err
}
if n > 0 {
return endOfBlock
}
n, err = d.br.readBits(1)
if err != nil {
return err
}
if n > 0 {
return endOfBlockAndFile
}
return endOfFile
}
func (d *lz29Decoder) decode(win *window) ([]byte, error) {
sym, err := d.mainDecoder.readSym(d.br)
if err != nil {
return nil, err
}
switch {
case sym < 256:
// literal
win.writeByte(byte(sym))
return nil, nil
case sym == 256:
return nil, d.readEndOfBlock()
case sym == 257:
return d.readFilterData()
case sym == 258:
// use previous offset and length
case sym < 263:
i := sym - 259
offset := d.offset[i]
copy(d.offset[1:i+1], d.offset[:i])
d.offset[0] = offset
i, err := d.lengthDecoder.readSym(d.br)
if err != nil {
return nil, err
}
d.length = lengthBase[i] + 2
bits := lengthExtraBits[i]
if bits > 0 {
n, err := d.br.readBits(bits)
if err != nil {
return nil, err
}
d.length += n
}
case sym < 271:
i := sym - 263
copy(d.offset[1:], d.offset[:])
offset := shortOffsetBase[i] + 1
bits := shortOffsetExtraBits[i]
if bits > 0 {
n, err := d.br.readBits(bits)
if err != nil {
return nil, err
}
offset += n
}
d.offset[0] = offset
d.length = 2
default:
i := sym - 271
d.length = lengthBase[i] + 3
bits := lengthExtraBits[i]
if bits > 0 {
n, err := d.br.readBits(bits)
if err != nil {
return nil, err
}
d.length += n
}
i, err = d.offsetDecoder.readSym(d.br)
if err != nil {
return nil, err
}
offset := offsetBase[i] + 1
bits = offsetExtraBits[i]
switch {
case bits >= 4:
if bits > 4 {
n, err := d.br.readBits(bits - 4)
if err != nil {
return nil, err
}
offset += n << 4
}
if d.lowOffsetRepeats > 0 {
d.lowOffsetRepeats--
offset += d.lowOffset
} else {
n, err := d.lowOffsetDecoder.readSym(d.br)
if err != nil {
return nil, err
}
if n == 16 {
d.lowOffsetRepeats = 15
offset += d.lowOffset
} else {
offset += n
d.lowOffset = n
}
}
case bits > 0:
n, err := d.br.readBits(bits)
if err != nil {
return nil, err
}
offset += n
}
if offset >= 0x2000 {
d.length++
if offset >= 0x40000 {
d.length++
}
}
copy(d.offset[1:], d.offset[:])
d.offset[0] = offset
}
win.copyBytes(d.length, d.offset[0])
return nil, nil
}