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Merge pull request #6534 from ChrisLundquist/clundquist/xz 

add support for xz compression #6523
This commit is contained in:
Megan Marsh 2018-08-24 14:15:55 -07:00 committed by GitHub
parent d356817890 718cff0208
commit 10c4aca521
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
47 changed files with 7586 additions and 1 deletions
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32
post-processor/compress/benchmark.go
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@ -105,6 +105,16 @@ func main() {
c.Close()
fmt.Printf("lz4:\twriter %s\treader %s\tsize %d\n", resw.T.String(), resr.T.String(), c.sw)
c, err = NewCompressor("/tmp/image.r", "/tmp/image.w")
if err != nil {
panic(err)
}
resw = testing.Benchmark(c.BenchmarkXZWriter)
c.w.Seek(0, 0)
resr = testing.Benchmark(c.BenchmarkXZReader)
c.Close()
fmt.Printf("xz:\twriter %s\treader %s\tsize %d\n", resw.T.String(), resr.T.String(), c.sw)
}
func (c *Compressor) BenchmarkGZIPWriter(b *testing.B) {
@ -195,3 +205,25 @@ func (c *Compressor) BenchmarkLZ4Reader(b *testing.B) {
b.Fatal(err)
}
}
func (c *Compressor) BenchmarkXZWriter(b *testing.B) {
cw := xz.NewWriter(c.w)
b.ResetTimer()
_, err := io.Copy(cw, c.r)
if err != nil {
b.Fatal(err)
}
cw.Close()
c.w.Sync()
}
func (c *Compressor) BenchmarkXZReader(b *testing.B) {
cr := xz.NewReader(c.w)
b.ResetTimer()
_, err := io.Copy(ioutil.Discard, cr)
if err != nil {
b.Fatal(err)
}
}

15
post-processor/compress/post-processor.go
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@ -18,6 +18,7 @@ import (
"github.com/hashicorp/packer/template/interpolate"
"github.com/klauspost/pgzip"
"github.com/pierrec/lz4"
"github.com/ulikunitz/xz"
)
var (
@ -142,6 +143,11 @@ func (p *PostProcessor) PostProcess(ui packer.Ui, artifact packer.Artifact) (pac
runtime.GOMAXPROCS(-1), target))
output, err = makeLZ4Writer(outputFile, p.config.CompressionLevel)
defer output.Close()
case "xz":
ui.Say(fmt.Sprintf("Using xz compression with 1 core for %s (library does not support MT)",
target))
output, err = makeXZWriter(outputFile, p.config.CompressionLevel)
defer output.Close()
case "pgzip":
ui.Say(fmt.Sprintf("Using pgzip compression with %d cores for %s",
runtime.GOMAXPROCS(-1), target))
@ -209,6 +215,7 @@ func (config *Config) detectFromFilename() {
"gz": "pgzip",
"lz4": "lz4",
"bgzf": "bgzf",
"xz": "xz",
}
if config.Format == "" {
@ -273,6 +280,14 @@ func makeLZ4Writer(output io.WriteCloser, compressionLevel int) (io.WriteCloser,
return lzwriter, nil
}
func makeXZWriter(output io.WriteCloser, compressionLevel int) (io.WriteCloser, error) {
xzwriter, err := xz.NewWriter(output)
if err != nil {
return nil, err
}
return xzwriter, nil
}
func makePgzipWriter(output io.WriteCloser, compressionLevel int) (io.WriteCloser, error) {
gzipWriter, err := pgzip.NewWriterLevel(output, compressionLevel)
if err != nil {

26
vendor/github.com/ulikunitz/xz/LICENSE generated vendored Normal file
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@ -0,0 +1,26 @@
Copyright (c) 2014-2016 Ulrich Kunitz
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:
* Redistributions of source code must retain the above copyright notice, this
list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above copyright notice,
this list of conditions and the following disclaimer in the documentation
and/or other materials provided with the distribution.
* My name, Ulrich Kunitz, may not be used to endorse or promote products
derived from this software without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

73
vendor/github.com/ulikunitz/xz/README.md generated vendored Normal file
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@ -0,0 +1,73 @@
# Package xz
This Go language package supports the reading and writing of xz
compressed streams. It includes also a gxz command for compressing and
decompressing data. The package is completely written in Go and doesn't
have any dependency on any C code.
The package is currently under development. There might be bugs and APIs
are not considered stable. At this time the package cannot compete with
the xz tool regarding compression speed and size. The algorithms there
have been developed over a long time and are highly optimized. However
there are a number of improvements planned and I'm very optimistic about
parallel compression and decompression. Stay tuned!
## Using the API
The following example program shows how to use the API.
```go
package main
import (
"bytes"
"io"
"log"
"os"
"github.com/ulikunitz/xz"
)
func main() {
const text = "The quick brown fox jumps over the lazy dog.\n"
var buf bytes.Buffer
// compress text
w, err := xz.NewWriter(&buf)
if err != nil {
log.Fatalf("xz.NewWriter error %s", err)
}
if _, err := io.WriteString(w, text); err != nil {
log.Fatalf("WriteString error %s", err)
}
if err := w.Close(); err != nil {
log.Fatalf("w.Close error %s", err)
}
// decompress buffer and write output to stdout
r, err := xz.NewReader(&buf)
if err != nil {
log.Fatalf("NewReader error %s", err)
}
if _, err = io.Copy(os.Stdout, r); err != nil {
log.Fatalf("io.Copy error %s", err)
}
}
```
## Using the gxz compression tool
The package includes a gxz command line utility for compression and
decompression.
Use following command for installation:
$ go get github.com/ulikunitz/xz/cmd/gxz
To test it call the following command.
$ gxz bigfile
After some time a much smaller file bigfile.xz will replace bigfile.
To decompress it use the following command.
$ gxz -d bigfile.xz

315
vendor/github.com/ulikunitz/xz/TODO.md generated vendored Normal file
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@ -0,0 +1,315 @@
# TODO list
## Release v0.6
1. Review encoder and check for lzma improvements under xz.
2. Fix binary tree matcher.
3. Compare compression ratio with xz tool using comparable parameters
and optimize parameters
4. Do some optimizations
- rename operation action and make it a simple type of size 8
- make maxMatches, wordSize parameters
- stop searching after a certain length is found (parameter sweetLen)
## Release v0.7
1. Optimize code
2. Do statistical analysis to get linear presets.
3. Test sync.Pool compatability for xz and lzma Writer and Reader
3. Fuzz optimized code.
## Release v0.8
1. Support parallel go routines for writing and reading xz files.
2. Support a ReaderAt interface for xz files with small block sizes.
3. Improve compatibility between gxz and xz
4. Provide manual page for gxz
## Release v0.9
1. Improve documentation
2. Fuzz again
## Release v1.0
1. Full functioning gxz
2. Add godoc URL to README.md (godoc.org)
3. Resolve all issues.
4. Define release candidates.
5. Public announcement.
## Package lzma
### Release v0.6
- Rewrite Encoder into a simple greedy one-op-at-a-time encoder
including
+ simple scan at the dictionary head for the same byte
+ use the killer byte (requiring matches to get longer, the first
test should be the byte that would make the match longer)
## Optimizations
- There may be a lot of false sharing in lzma.State; check whether this
can be improved by reorganizing the internal structure of it.
- Check whether batching encoding and decoding improves speed.
### DAG optimizations
- Use full buffer to create minimal bit-length above range encoder.
- Might be too slow (see v0.4)
### Different match finders
- hashes with 2, 3 characters additional to 4 characters
- binary trees with 2-7 characters (uint64 as key, use uint32 as
pointers into a an array)
- rb-trees with 2-7 characters (uint64 as key, use uint32 as pointers
into an array with bit-steeling for the colors)
## Release Procedure
- execute goch -l for all packages; probably with lower param like 0.5.
- check orthography with gospell
- Write release notes in doc/relnotes.
- Update README.md
- xb copyright . in xz directory to ensure all new files have Copyright
header
- VERSION=<version> go generate github.com/ulikunitz/xz/... to update
version files
- Execute test for Linux/amd64, Linux/x86 and Windows/amd64.
- Update TODO.md - write short log entry
- git checkout master && git merge dev
- git tag -a <version>
- git push
## Log
### 2017-06-05
Release v0.5.4 fixes issues #15 of another problem with the padding size
check for the xz block header. I removed the check completely.
### 2017-02-15
Release v0.5.3 fixes issue #12 regarding the decompression of an empty
XZ stream. Many thanks to Tomasz Kłak, who reported the issue.
### 2016-12-02
Release v0.5.2 became necessary to allow the decoding of xz files with
4-byte padding in the block header. Many thanks to Greg, who reported
the issue.
### 2016-07-23
Release v0.5.1 became necessary to fix problems with 32-bit platforms.
Many thanks to Bruno Brigas, who reported the issue.
### 2016-07-04
Release v0.5 provides improvements to the compressor and provides support for
the decompression of xz files with multiple xz streams.
### 2016-01-31
Another compression rate increase by checking the byte at length of the
best match first, before checking the whole prefix. This makes the
compressor even faster. We have now a large time budget to beat the
compression ratio of the xz tool. For enwik8 we have now over 40 seconds
to reduce the compressed file size for another 7 MiB.
### 2016-01-30
I simplified the encoder. Speed and compression rate increased
dramatically. A high compression rate affects also the decompression
speed. The approach with the buffer and optimizing for operation
compression rate has not been successful. Going for the maximum length
appears to be the best approach.
### 2016-01-28
The release v0.4 is ready. It provides a working xz implementation,
which is rather slow, but works and is interoperable with the xz tool.
It is an important milestone.
### 2016-01-10
I have the first working implementation of an xz reader and writer. I'm
happy about reaching this milestone.
### 2015-12-02
I'm now ready to implement xz because, I have a working LZMA2
implementation. I decided today that v0.4 will use the slow encoder
using the operations buffer to be able to go back, if I intend to do so.
### 2015-10-21
I have restarted the work on the library. While trying to implement
LZMA2, I discovered that I need to resimplify the encoder and decoder
functions. The option approach is too complicated. Using a limited byte
writer and not caring for written bytes at all and not to try to handle
uncompressed data simplifies the LZMA encoder and decoder much.
Processing uncompressed data and handling limits is a feature of the
LZMA2 format not of LZMA.
I learned an interesting method from the LZO format. If the last copy is
too far away they are moving the head one 2 bytes and not 1 byte to
reduce processing times.
### 2015-08-26
I have now reimplemented the lzma package. The code is reasonably fast,
but can still be optimized. The next step is to implement LZMA2 and then
xz.
### 2015-07-05
Created release v0.3. The version is the foundation for a full xz
implementation that is the target of v0.4.
### 2015-06-11
The gflag package has been developed because I couldn't use flag and
pflag for a fully compatible support of gzip's and lzma's options. It
seems to work now quite nicely.
### 2015-06-05
The overflow issue was interesting to research, however Henry S. Warren
Jr. Hacker's Delight book was very helpful as usual and had the issue
explained perfectly. Fefe's information on his website was based on the
C FAQ and quite bad, because it didn't address the issue of -MININT ==
MININT.
### 2015-06-04
It has been a productive day. I improved the interface of lzma.Reader
and lzma.Writer and fixed the error handling.
### 2015-06-01
By computing the bit length of the LZMA operations I was able to
improve the greedy algorithm implementation. By using an 8 MByte buffer
the compression rate was not as good as for xz but already better then
gzip default.
Compression is currently slow, but this is something we will be able to
improve over time.
### 2015-05-26
Checked the license of ogier/pflag. The binary lzmago binary should
include the license terms for the pflag library.
I added the endorsement clause as used by Google for the Go sources the
LICENSE file.
### 2015-05-22
The package lzb contains now the basic implementation for creating or
reading LZMA byte streams. It allows the support for the implementation
of the DAG-shortest-path algorithm for the compression function.
### 2015-04-23
Completed yesterday the lzbase classes. I'm a little bit concerned that
using the components may require too much code, but on the other hand
there is a lot of flexibility.
### 2015-04-22
Implemented Reader and Writer during the Bayern game against Porto. The
second half gave me enough time.
### 2015-04-21
While showering today morning I discovered that the design for OpEncoder
and OpDecoder doesn't work, because encoding/decoding might depend on
the current status of the dictionary. This is not exactly the right way
to start the day.
Therefore we need to keep the Reader and Writer design. This time around
we simplify it by ignoring size limits. These can be added by wrappers
around the Reader and Writer interfaces. The Parameters type isn't
needed anymore.
However I will implement a ReaderState and WriterState type to use
static typing to ensure the right State object is combined with the
right lzbase.Reader and lzbase.Writer.
As a start I have implemented ReaderState and WriterState to ensure
that the state for reading is only used by readers and WriterState only
used by Writers.
### 2015-04-20
Today I implemented the OpDecoder and tested OpEncoder and OpDecoder.
### 2015-04-08
Came up with a new simplified design for lzbase. I implemented already
the type State that replaces OpCodec.
### 2015-04-06
The new lzma package is now fully usable and lzmago is using it now. The
old lzma package has been completely removed.
### 2015-04-05
Implemented lzma.Reader and tested it.
### 2015-04-04
Implemented baseReader by adapting code form lzma.Reader.
### 2015-04-03
The opCodec has been copied yesterday to lzma2. opCodec has a high
number of dependencies on other files in lzma2. Therefore I had to copy
almost all files from lzma.
### 2015-03-31
Removed only a TODO item.
However in Francesco Campoy's presentation "Go for Javaneros
(Javaïstes?)" is the the idea that using an embedded field E, all the
methods of E will be defined on T. If E is an interface T satisfies E.
https://talks.golang.org/2014/go4java.slide#51
I have never used this, but it seems to be a cool idea.
### 2015-03-30
Finished the type writerDict and wrote a simple test.
### 2015-03-25
I started to implement the writerDict.
### 2015-03-24
After thinking long about the LZMA2 code and several false starts, I
have now a plan to create a self-sufficient lzma2 package that supports
the classic LZMA format as well as LZMA2. The core idea is to support a
baseReader and baseWriter type that support the basic LZMA stream
without any headers. Both types must support the reuse of dictionaries
and the opCodec.
### 2015-01-10
1. Implemented simple lzmago tool
2. Tested tool against large 4.4G file
- compression worked correctly; tested decompression with lzma
- decompression hits a full buffer condition
3. Fixed a bug in the compressor and wrote a test for it
4. Executed full cycle for 4.4 GB file; performance can be improved ;-)
### 2015-01-11
- Release v0.2 because of the working LZMA encoder and decoder

74
vendor/github.com/ulikunitz/xz/bits.go generated vendored Normal file
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@ -0,0 +1,74 @@
// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package xz
import (
"errors"
"io"
)
// putUint32LE puts the little-endian representation of x into the first
// four bytes of p.
func putUint32LE(p []byte, x uint32) {
p[0] = byte(x)
p[1] = byte(x >> 8)
p[2] = byte(x >> 16)
p[3] = byte(x >> 24)
}
// putUint64LE puts the little-endian representation of x into the first
// eight bytes of p.
func putUint64LE(p []byte, x uint64) {
p[0] = byte(x)
p[1] = byte(x >> 8)
p[2] = byte(x >> 16)
p[3] = byte(x >> 24)
p[4] = byte(x >> 32)
p[5] = byte(x >> 40)
p[6] = byte(x >> 48)
p[7] = byte(x >> 56)
}
// uint32LE converts a little endian representation to an uint32 value.
func uint32LE(p []byte) uint32 {
return uint32(p[0]) | uint32(p[1])<<8 | uint32(p[2])<<16 |
uint32(p[3])<<24
}
// putUvarint puts a uvarint representation of x into the byte slice.
func putUvarint(p []byte, x uint64) int {
i := 0
for x >= 0x80 {
p[i] = byte(x) | 0x80
x >>= 7
i++
}
p[i] = byte(x)
return i + 1
}
// errOverflow indicates an overflow of the 64-bit unsigned integer.
var errOverflowU64 = errors.New("xz: uvarint overflows 64-bit unsigned integer")
// readUvarint reads a uvarint from the given byte reader.
func readUvarint(r io.ByteReader) (x uint64, n int, err error) {
var s uint
i := 0
for {
b, err := r.ReadByte()
if err != nil {
return x, i, err
}
i++
if b < 0x80 {
if i > 10 || i == 10 && b > 1 {
return x, i, errOverflowU64
}
return x | uint64(b)<<s, i, nil
}
x |= uint64(b&0x7f) << s
s += 7
}
}

54
vendor/github.com/ulikunitz/xz/crc.go generated vendored Normal file
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@ -0,0 +1,54 @@
// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package xz
import (
"hash"
"hash/crc32"
"hash/crc64"
)
// crc32Hash implements the hash.Hash32 interface with Sum returning the
// crc32 value in little-endian encoding.
type crc32Hash struct {
hash.Hash32
}
// Sum returns the crc32 value as little endian.
func (h crc32Hash) Sum(b []byte) []byte {
p := make([]byte, 4)
putUint32LE(p, h.Hash32.Sum32())
b = append(b, p...)
return b
}
// newCRC32 returns a CRC-32 hash that returns the 64-bit value in
// little-endian encoding using the IEEE polynomial.
func newCRC32() hash.Hash {
return crc32Hash{Hash32: crc32.NewIEEE()}
}
// crc64Hash implements the Hash64 interface with Sum returning the
// CRC-64 value in little-endian encoding.
type crc64Hash struct {
hash.Hash64
}
// Sum returns the CRC-64 value in little-endian encoding.
func (h crc64Hash) Sum(b []byte) []byte {
p := make([]byte, 8)
putUint64LE(p, h.Hash64.Sum64())
b = append(b, p...)
return b
}
// crc64Table is used to create a CRC-64 hash.
var crc64Table = crc64.MakeTable(crc64.ECMA)
// newCRC64 returns a CRC-64 hash that returns the 64-bit value in
// little-endian encoding using the ECMA polynomial.
func newCRC64() hash.Hash {
return crc64Hash{Hash64: crc64.New(crc64Table)}
}

728
vendor/github.com/ulikunitz/xz/format.go generated vendored Normal file
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@ -0,0 +1,728 @@
// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package xz
import (
"bytes"
"crypto/sha256"
"errors"
"fmt"
"hash"
"hash/crc32"
"io"
"github.com/ulikunitz/xz/lzma"
)
// allZeros checks whether a given byte slice has only zeros.
func allZeros(p []byte) bool {
for _, c := range p {
if c != 0 {
return false
}
}
return true
}
// padLen returns the length of the padding required for the given
// argument.
func padLen(n int64) int {
k := int(n % 4)
if k > 0 {
k = 4 - k
}
return k
}
/*** Header ***/
// headerMagic stores the magic bytes for the header
var headerMagic = []byte{0xfd, '7', 'z', 'X', 'Z', 0x00}
// HeaderLen provides the length of the xz file header.
const HeaderLen = 12
// Constants for the checksum methods supported by xz.
const (
CRC32 byte = 0x1
CRC64 = 0x4
SHA256 = 0xa
)
// errInvalidFlags indicates that flags are invalid.
var errInvalidFlags = errors.New("xz: invalid flags")
// verifyFlags returns the error errInvalidFlags if the value is
// invalid.
func verifyFlags(flags byte) error {
switch flags {
case CRC32, CRC64, SHA256:
return nil
default:
return errInvalidFlags
}
}
// flagstrings maps flag values to strings.
var flagstrings = map[byte]string{
CRC32: "CRC-32",
CRC64: "CRC-64",
SHA256: "SHA-256",
}
// flagString returns the string representation for the given flags.
func flagString(flags byte) string {
s, ok := flagstrings[flags]
if !ok {
return "invalid"
}
return s
}
// newHashFunc returns a function that creates hash instances for the
// hash method encoded in flags.
func newHashFunc(flags byte) (newHash func() hash.Hash, err error) {
switch flags {
case CRC32:
newHash = newCRC32
case CRC64:
newHash = newCRC64
case SHA256:
newHash = sha256.New
default:
err = errInvalidFlags
}
return
}
// header provides the actual content of the xz file header: the flags.
type header struct {
flags byte
}
// Errors returned by readHeader.
var errHeaderMagic = errors.New("xz: invalid header magic bytes")
// ValidHeader checks whether data is a correct xz file header. The
// length of data must be HeaderLen.
func ValidHeader(data []byte) bool {
var h header
err := h.UnmarshalBinary(data)
return err == nil
}
// String returns a string representation of the flags.
func (h header) String() string {
return flagString(h.flags)
}
// UnmarshalBinary reads header from the provided data slice.
func (h *header) UnmarshalBinary(data []byte) error {
// header length
if len(data) != HeaderLen {
return errors.New("xz: wrong file header length")
}
// magic header
if !bytes.Equal(headerMagic, data[:6]) {
return errHeaderMagic
}
// checksum
crc := crc32.NewIEEE()
crc.Write(data[6:8])
if uint32LE(data[8:]) != crc.Sum32() {
return errors.New("xz: invalid checksum for file header")
}
// stream flags
if data[6] != 0 {
return errInvalidFlags
}
flags := data[7]
if err := verifyFlags(flags); err != nil {
return err
}
h.flags = flags
return nil
}
// MarshalBinary generates the xz file header.
func (h *header) MarshalBinary() (data []byte, err error) {
if err = verifyFlags(h.flags); err != nil {
return nil, err
}
data = make([]byte, 12)
copy(data, headerMagic)
data[7] = h.flags
crc := crc32.NewIEEE()
crc.Write(data[6:8])
putUint32LE(data[8:], crc.Sum32())
return data, nil
}
/*** Footer ***/
// footerLen defines the length of the footer.
const footerLen = 12
// footerMagic contains the footer magic bytes.
var footerMagic = []byte{'Y', 'Z'}
// footer represents the content of the xz file footer.
type footer struct {
indexSize int64
flags byte
}
// String prints a string representation of the footer structure.
func (f footer) String() string {
return fmt.Sprintf("%s index size %d", flagString(f.flags), f.indexSize)
}
// Minimum and maximum for the size of the index (backward size).
const (
minIndexSize = 4
maxIndexSize = (1 << 32) * 4
)
// MarshalBinary converts footer values into an xz file footer. Note
// that the footer value is checked for correctness.
func (f *footer) MarshalBinary() (data []byte, err error) {
if err = verifyFlags(f.flags); err != nil {
return nil, err
}
if !(minIndexSize <= f.indexSize && f.indexSize <= maxIndexSize) {
return nil, errors.New("xz: index size out of range")
}
if f.indexSize%4 != 0 {
return nil, errors.New(
"xz: index size not aligned to four bytes")
}
data = make([]byte, footerLen)
// backward size (index size)
s := (f.indexSize / 4) - 1
putUint32LE(data[4:], uint32(s))
// flags
data[9] = f.flags
// footer magic
copy(data[10:], footerMagic)
// CRC-32
crc := crc32.NewIEEE()
crc.Write(data[4:10])
putUint32LE(data, crc.Sum32())
return data, nil
}
// UnmarshalBinary sets the footer value by unmarshalling an xz file
// footer.
func (f *footer) UnmarshalBinary(data []byte) error {
if len(data) != footerLen {
return errors.New("xz: wrong footer length")
}
// magic bytes
if !bytes.Equal(data[10:], footerMagic) {
return errors.New("xz: footer magic invalid")
}
// CRC-32
crc := crc32.NewIEEE()
crc.Write(data[4:10])
if uint32LE(data) != crc.Sum32() {
return errors.New("xz: footer checksum error")
}
var g footer
// backward size (index size)
g.indexSize = (int64(uint32LE(data[4:])) + 1) * 4
// flags
if data[8] != 0 {
return errInvalidFlags
}
g.flags = data[9]
if err := verifyFlags(g.flags); err != nil {
return err
}
*f = g
return nil
}
/*** Block Header ***/
// blockHeader represents the content of an xz block header.
type blockHeader struct {
compressedSize int64
uncompressedSize int64
filters []filter
}
// String converts the block header into a string.
func (h blockHeader) String() string {
var buf bytes.Buffer
first := true
if h.compressedSize >= 0 {
fmt.Fprintf(&buf, "compressed size %d", h.compressedSize)
first = false
}
if h.uncompressedSize >= 0 {
if !first {
buf.WriteString(" ")
}
fmt.Fprintf(&buf, "uncompressed size %d", h.uncompressedSize)
first = false
}
for _, f := range h.filters {
if !first {
buf.WriteString(" ")
}
fmt.Fprintf(&buf, "filter %s", f)
first = false
}
return buf.String()
}
// Masks for the block flags.
const (
filterCountMask = 0x03
compressedSizePresent = 0x40
uncompressedSizePresent = 0x80
reservedBlockFlags = 0x3C
)
// errIndexIndicator signals that an index indicator (0x00) has been found
// instead of an expected block header indicator.
var errIndexIndicator = errors.New("xz: found index indicator")
// readBlockHeader reads the block header.
func readBlockHeader(r io.Reader) (h *blockHeader, n int, err error) {
var buf bytes.Buffer
buf.Grow(20)
// block header size
z, err := io.CopyN(&buf, r, 1)
n = int(z)
if err != nil {
return nil, n, err
}
s := buf.Bytes()[0]
if s == 0 {
return nil, n, errIndexIndicator
}
// read complete header
headerLen := (int(s) + 1) * 4
buf.Grow(headerLen - 1)
z, err = io.CopyN(&buf, r, int64(headerLen-1))
n += int(z)
if err != nil {
return nil, n, err
}
// unmarshal block header
h = new(blockHeader)
if err = h.UnmarshalBinary(buf.Bytes()); err != nil {
return nil, n, err
}
return h, n, nil
}
// readSizeInBlockHeader reads the uncompressed or compressed size
// fields in the block header. The present value informs the function
// whether the respective field is actually present in the header.
func readSizeInBlockHeader(r io.ByteReader, present bool) (n int64, err error) {
if !present {
return -1, nil
}
x, _, err := readUvarint(r)
if err != nil {
return 0, err
}
if x >= 1<<63 {
return 0, errors.New("xz: size overflow in block header")
}
return int64(x), nil
}
// UnmarshalBinary unmarshals the block header.
func (h *blockHeader) UnmarshalBinary(data []byte) error {
// Check header length
s := data[0]
if data[0] == 0 {
return errIndexIndicator
}
headerLen := (int(s) + 1) * 4
if len(data) != headerLen {
return fmt.Errorf("xz: data length %d; want %d", len(data),
headerLen)
}
n := headerLen - 4
// Check CRC-32
crc := crc32.NewIEEE()
crc.Write(data[:n])
if crc.Sum32() != uint32LE(data[n:]) {
return errors.New("xz: checksum error for block header")
}
// Block header flags
flags := data[1]
if flags&reservedBlockFlags != 0 {
return errors.New("xz: reserved block header flags set")
}
r := bytes.NewReader(data[2:n])
// Compressed size
var err error
h.compressedSize, err = readSizeInBlockHeader(
r, flags&compressedSizePresent != 0)
if err != nil {
return err
}
// Uncompressed size
h.uncompressedSize, err = readSizeInBlockHeader(
r, flags&uncompressedSizePresent != 0)
if err != nil {
return err
}
h.filters, err = readFilters(r, int(flags&filterCountMask)+1)
if err != nil {
return err
}
// Check padding
// Since headerLen is a multiple of 4 we don't need to check
// alignment.
k := r.Len()
// The standard spec says that the padding should have not more
// than 3 bytes. However we found paddings of 4 or 5 in the
// wild. See https://github.com/ulikunitz/xz/pull/11 and
// https://github.com/ulikunitz/xz/issues/15
//
// The only reasonable approach seems to be to ignore the
// padding size. We still check that all padding bytes are zero.
if !allZeros(data[n-k : n]) {
return errPadding
}
return nil
}
// MarshalBinary marshals the binary header.
func (h *blockHeader) MarshalBinary() (data []byte, err error) {
if !(minFilters <= len(h.filters) && len(h.filters) <= maxFilters) {
return nil, errors.New("xz: filter count wrong")
}
for i, f := range h.filters {
if i < len(h.filters)-1 {
if f.id() == lzmaFilterID {
return nil, errors.New(
"xz: LZMA2 filter is not the last")
}
} else {
// last filter
if f.id() != lzmaFilterID {
return nil, errors.New("xz: " +
"last filter must be the LZMA2 filter")
}
}
}
var buf bytes.Buffer
// header size must set at the end
buf.WriteByte(0)
// flags
flags := byte(len(h.filters) - 1)
if h.compressedSize >= 0 {
flags |= compressedSizePresent
}
if h.uncompressedSize >= 0 {
flags |= uncompressedSizePresent
}
buf.WriteByte(flags)
p := make([]byte, 10)
if h.compressedSize >= 0 {
k := putUvarint(p, uint64(h.compressedSize))
buf.Write(p[:k])
}
if h.uncompressedSize >= 0 {
k := putUvarint(p, uint64(h.uncompressedSize))
buf.Write(p[:k])
}
for _, f := range h.filters {
fp, err := f.MarshalBinary()
if err != nil {
return nil, err
}
buf.Write(fp)
}
// padding
for i := padLen(int64(buf.Len())); i > 0; i-- {
buf.WriteByte(0)
}
// crc place holder
buf.Write(p[:4])
data = buf.Bytes()
if len(data)%4 != 0 {
panic("data length not aligned")
}
s := len(data)/4 - 1
if !(1 < s && s <= 255) {
panic("wrong block header size")
}
data[0] = byte(s)
crc := crc32.NewIEEE()
crc.Write(data[:len(data)-4])
putUint32LE(data[len(data)-4:], crc.Sum32())
return data, nil
}
// Constants used for marshalling and unmarshalling filters in the xz
// block header.
const (
minFilters = 1
maxFilters = 4
minReservedID = 1 << 62
)
// filter represents a filter in the block header.
type filter interface {
id() uint64
UnmarshalBinary(data []byte) error
MarshalBinary() (data []byte, err error)
reader(r io.Reader, c *ReaderConfig) (fr io.Reader, err error)
writeCloser(w io.WriteCloser, c *WriterConfig) (fw io.WriteCloser, err error)
// filter must be last filter
last() bool
}
// readFilter reads a block filter from the block header. At this point
// in time only the LZMA2 filter is supported.
func readFilter(r io.Reader) (f filter, err error) {
br := lzma.ByteReader(r)
// index
id, _, err := readUvarint(br)
if err != nil {
return nil, err
}
var data []byte
switch id {
case lzmaFilterID:
data = make([]byte, lzmaFilterLen)
data[0] = lzmaFilterID
if _, err = io.ReadFull(r, data[1:]); err != nil {
return nil, err
}
f = new(lzmaFilter)
default:
if id >= minReservedID {
return nil, errors.New(
"xz: reserved filter id in block stream header")
}
return nil, errors.New("xz: invalid filter id")
}
if err = f.UnmarshalBinary(data); err != nil {
return nil, err
}
return f, err
}
// readFilters reads count filters. At this point in time only the count
// 1 is supported.
func readFilters(r io.Reader, count int) (filters []filter, err error) {
if count != 1 {
return nil, errors.New("xz: unsupported filter count")
}
f, err := readFilter(r)
if err != nil {
return nil, err
}
return []filter{f}, err
}
// writeFilters writes the filters.
func writeFilters(w io.Writer, filters []filter) (n int, err error) {
for _, f := range filters {
p, err := f.MarshalBinary()
if err != nil {
return n, err
}
k, err := w.Write(p)
n += k
if err != nil {
return n, err
}
}
return n, nil
}
/*** Index ***/
// record describes a block in the xz file index.
type record struct {
unpaddedSize int64
uncompressedSize int64
}
// readRecord reads an index record.
func readRecord(r io.ByteReader) (rec record, n int, err error) {
u, k, err := readUvarint(r)
n += k
if err != nil {
return rec, n, err
}
rec.unpaddedSize = int64(u)
if rec.unpaddedSize < 0 {
return rec, n, errors.New("xz: unpadded size negative")
}
u, k, err = readUvarint(r)
n += k
if err != nil {
return rec, n, err
}
rec.uncompressedSize = int64(u)
if rec.uncompressedSize < 0 {
return rec, n, errors.New("xz: uncompressed size negative")
}
return rec, n, nil
}
// MarshalBinary converts an index record in its binary encoding.
func (rec *record) MarshalBinary() (data []byte, err error) {
// maximum length of a uvarint is 10
p := make([]byte, 20)
n := putUvarint(p, uint64(rec.unpaddedSize))
n += putUvarint(p[n:], uint64(rec.uncompressedSize))
return p[:n], nil
}
// writeIndex writes the index, a sequence of records.
func writeIndex(w io.Writer, index []record) (n int64, err error) {
crc := crc32.NewIEEE()
mw := io.MultiWriter(w, crc)
// index indicator
k, err := mw.Write([]byte{0})
n += int64(k)
if err != nil {
return n, err
}
// number of records
p := make([]byte, 10)
k = putUvarint(p, uint64(len(index)))
k, err = mw.Write(p[:k])
n += int64(k)
if err != nil {
return n, err
}
// list of records
for _, rec := range index {
p, err := rec.MarshalBinary()
if err != nil {
return n, err
}
k, err = mw.Write(p)
n += int64(k)
if err != nil {
return n, err
}
}
// index padding
k, err = mw.Write(make([]byte, padLen(int64(n))))
n += int64(k)
if err != nil {
return n, err
}
// crc32 checksum
putUint32LE(p, crc.Sum32())
k, err = w.Write(p[:4])
n += int64(k)
return n, err
}
// readIndexBody reads the index from the reader. It assumes that the
// index indicator has already been read.
func readIndexBody(r io.Reader) (records []record, n int64, err error) {
crc := crc32.NewIEEE()
// index indicator
crc.Write([]byte{0})
br := lzma.ByteReader(io.TeeReader(r, crc))
// number of records
u, k, err := readUvarint(br)
n += int64(k)
if err != nil {
return nil, n, err
}
recLen := int(u)
if recLen < 0 || uint64(recLen) != u {
return nil, n, errors.New("xz: record number overflow")
}
// list of records
records = make([]record, recLen)
for i := range records {
records[i], k, err = readRecord(br)
n += int64(k)
if err != nil {
return nil, n, err
}
}
p := make([]byte, padLen(int64(n+1)), 4)
k, err = io.ReadFull(br.(io.Reader), p)
n += int64(k)
if err != nil {
return nil, n, err
}
if !allZeros(p) {
return nil, n, errors.New("xz: non-zero byte in index padding")
}
// crc32
s := crc.Sum32()
p = p[:4]
k, err = io.ReadFull(br.(io.Reader), p)
n += int64(k)
if err != nil {
return records, n, err
}
if uint32LE(p) != s {
return nil, n, errors.New("xz: wrong checksum for index")
}
return records, n, nil
}

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// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package hash
// CyclicPoly provides a cyclic polynomial rolling hash.
type CyclicPoly struct {
h uint64
p []uint64
i int
}
// ror rotates the unsigned 64-bit integer to right. The argument s must be
// less than 64.
func ror(x uint64, s uint) uint64 {
return (x >> s) | (x << (64 - s))
}
// NewCyclicPoly creates a new instance of the CyclicPoly structure. The
// argument n gives the number of bytes for which a hash will be executed.
// This number must be positive; the method panics if this isn't the case.
func NewCyclicPoly(n int) *CyclicPoly {
if n < 1 {
panic("argument n must be positive")
}
return &CyclicPoly{p: make([]uint64, 0, n)}
}
// Len returns the length of the byte sequence for which a hash is generated.
func (r *CyclicPoly) Len() int {
return cap(r.p)
}
// RollByte hashes the next byte and returns a hash value. The complete becomes
// available after at least Len() bytes have been hashed.
func (r *CyclicPoly) RollByte(x byte) uint64 {
y := hash[x]
if len(r.p) < cap(r.p) {
r.h = ror(r.h, 1) ^ y
r.p = append(r.p, y)
} else {
r.h ^= ror(r.p[r.i], uint(cap(r.p)-1))
r.h = ror(r.h, 1) ^ y
r.p[r.i] = y
r.i = (r.i + 1) % cap(r.p)
}
return r.h
}
// Stores the hash for the individual bytes.
var hash = [256]uint64{
0x2e4fc3f904065142, 0xc790984cfbc99527,
0x879f95eb8c62f187, 0x3b61be86b5021ef2,
0x65a896a04196f0a5, 0xc5b307b80470b59e,
0xd3bff376a70df14b, 0xc332f04f0b3f1701,
0x753b5f0e9abf3e0d, 0xb41538fdfe66ef53,
0x1906a10c2c1c0208, 0xfb0c712a03421c0d,
0x38be311a65c9552b, 0xfee7ee4ca6445c7e,
0x71aadeded184f21e, 0xd73426fccda23b2d,
0x29773fb5fb9600b5, 0xce410261cd32981a,
0xfe2848b3c62dbc2d, 0x459eaaff6e43e11c,
0xc13e35fc9c73a887, 0xf30ed5c201e76dbc,
0xa5f10b3910482cea, 0x2945d59be02dfaad,
0x06ee334ff70571b5, 0xbabf9d8070f44380,
0xee3e2e9912ffd27c, 0x2a7118d1ea6b8ea7,
0x26183cb9f7b1664c, 0xea71dac7da068f21,
0xea92eca5bd1d0bb7, 0x415595862defcd75,
0x248a386023c60648, 0x9cf021ab284b3c8a,
0xfc9372df02870f6c, 0x2b92d693eeb3b3fc,
0x73e799d139dc6975, 0x7b15ae312486363c,
0xb70e5454a2239c80, 0x208e3fb31d3b2263,
0x01f563cabb930f44, 0x2ac4533d2a3240d8,
0x84231ed1064f6f7c, 0xa9f020977c2a6d19,
0x213c227271c20122, 0x09fe8a9a0a03d07a,
0x4236dc75bcaf910c, 0x460a8b2bead8f17e,
0xd9b27be1aa07055f, 0xd202d5dc4b11c33e,
0x70adb010543bea12, 0xcdae938f7ea6f579,
0x3f3d870208672f4d, 0x8e6ccbce9d349536,
0xe4c0871a389095ae, 0xf5f2a49152bca080,
0x9a43f9b97269934e, 0xc17b3753cb6f475c,
0xd56d941e8e206bd4, 0xac0a4f3e525eda00,
0xa06d5a011912a550, 0x5537ed19537ad1df,
0xa32fe713d611449d, 0x2a1d05b47c3b579f,
0x991d02dbd30a2a52, 0x39e91e7e28f93eb0,
0x40d06adb3e92c9ac, 0x9b9d3afde1c77c97,
0x9a3f3f41c02c616f, 0x22ecd4ba00f60c44,
0x0b63d5d801708420, 0x8f227ca8f37ffaec,
0x0256278670887c24, 0x107e14877dbf540b,
0x32c19f2786ac1c05, 0x1df5b12bb4bc9c61,
0xc0cac129d0d4c4e2, 0x9fdb52ee9800b001,
0x31f601d5d31c48c4, 0x72ff3c0928bcaec7,
0xd99264421147eb03, 0x535a2d6d38aefcfe,
0x6ba8b4454a916237, 0xfa39366eaae4719c,
0x10f00fd7bbb24b6f, 0x5bd23185c76c84d4,
0xb22c3d7e1b00d33f, 0x3efc20aa6bc830a8,
0xd61c2503fe639144, 0x30ce625441eb92d3,
0xe5d34cf359e93100, 0xa8e5aa13f2b9f7a5,
0x5c2b8d851ca254a6, 0x68fb6c5e8b0d5fdf,
0xc7ea4872c96b83ae, 0x6dd5d376f4392382,
0x1be88681aaa9792f, 0xfef465ee1b6c10d9,
0x1f98b65ed43fcb2e, 0x4d1ca11eb6e9a9c9,
0x7808e902b3857d0b, 0x171c9c4ea4607972,
0x58d66274850146df, 0x42b311c10d3981d1,
0x647fa8c621c41a4c, 0xf472771c66ddfedc,
0x338d27e3f847b46b, 0x6402ce3da97545ce,
0x5162db616fc38638, 0x9c83be97bc22a50e,
0x2d3d7478a78d5e72, 0xe621a9b938fd5397,
0x9454614eb0f81c45, 0x395fb6e742ed39b6,
0x77dd9179d06037bf, 0xc478d0fee4d2656d,
0x35d9d6cb772007af, 0x83a56e92c883f0f6,
0x27937453250c00a1, 0x27bd6ebc3a46a97d,
0x9f543bf784342d51, 0xd158f38c48b0ed52,
0x8dd8537c045f66b4, 0x846a57230226f6d5,
0x6b13939e0c4e7cdf, 0xfca25425d8176758,
0x92e5fc6cd52788e6, 0x9992e13d7a739170,
0x518246f7a199e8ea, 0xf104c2a71b9979c7,
0x86b3ffaabea4768f, 0x6388061cf3e351ad,
0x09d9b5295de5bbb5, 0x38bf1638c2599e92,
0x1d759846499e148d, 0x4c0ff015e5f96ef4,
0xa41a94cfa270f565, 0x42d76f9cb2326c0b,
0x0cf385dd3c9c23ba, 0x0508a6c7508d6e7a,
0x337523aabbe6cf8d, 0x646bb14001d42b12,
0xc178729d138adc74, 0xf900ef4491f24086,
0xee1a90d334bb5ac4, 0x9755c92247301a50,
0xb999bf7c4ff1b610, 0x6aeeb2f3b21e8fc9,
0x0fa8084cf91ac6ff, 0x10d226cf136e6189,
0xd302057a07d4fb21, 0x5f03800e20a0fcc3,
0x80118d4ae46bd210, 0x58ab61a522843733,
0x51edd575c5432a4b, 0x94ee6ff67f9197f7,
0x765669e0e5e8157b, 0xa5347830737132f0,
0x3ba485a69f01510c, 0x0b247d7b957a01c3,
0x1b3d63449fd807dc, 0x0fdc4721c30ad743,
0x8b535ed3829b2b14, 0xee41d0cad65d232c,
0xe6a99ed97a6a982f, 0x65ac6194c202003d,
0x692accf3a70573eb, 0xcc3c02c3e200d5af,
0x0d419e8b325914a3, 0x320f160f42c25e40,
0x00710d647a51fe7a, 0x3c947692330aed60,
0x9288aa280d355a7a, 0xa1806a9b791d1696,
0x5d60e38496763da1, 0x6c69e22e613fd0f4,
0x977fc2a5aadffb17, 0xfb7bd063fc5a94ba,
0x460c17992cbaece1, 0xf7822c5444d3297f,
0x344a9790c69b74aa, 0xb80a42e6cae09dce,
0x1b1361eaf2b1e757, 0xd84c1e758e236f01,
0x88e0b7be347627cc, 0x45246009b7a99490,
0x8011c6dd3fe50472, 0xc341d682bffb99d7,
0x2511be93808e2d15, 0xd5bc13d7fd739840,
0x2a3cd030679ae1ec, 0x8ad9898a4b9ee157,
0x3245fef0a8eaf521, 0x3d6d8dbbb427d2b0,
0x1ed146d8968b3981, 0x0c6a28bf7d45f3fc,
0x4a1fd3dbcee3c561, 0x4210ff6a476bf67e,
0xa559cce0d9199aac, 0xde39d47ef3723380,
0xe5b69d848ce42e35, 0xefa24296f8e79f52,
0x70190b59db9a5afc, 0x26f166cdb211e7bf,
0x4deaf2df3c6b8ef5, 0xf171dbdd670f1017,
0xb9059b05e9420d90, 0x2f0da855c9388754,
0x611d5e9ab77949cc, 0x2912038ac01163f4,
0x0231df50402b2fba, 0x45660fc4f3245f58,
0xb91cc97c7c8dac50, 0xb72d2aafe4953427,
0xfa6463f87e813d6b, 0x4515f7ee95d5c6a2,
0x1310e1c1a48d21c3, 0xad48a7810cdd8544,
0x4d5bdfefd5c9e631, 0xa43ed43f1fdcb7de,
0xe70cfc8fe1ee9626, 0xef4711b0d8dda442,
0xb80dd9bd4dab6c93, 0xa23be08d31ba4d93,
0x9b37db9d0335a39c, 0x494b6f870f5cfebc,
0x6d1b3c1149dda943, 0x372c943a518c1093,
0xad27af45e77c09c4, 0x3b6f92b646044604,
0xac2917909f5fcf4f, 0x2069a60e977e5557,
0x353a469e71014de5, 0x24be356281f55c15,
0x2b6d710ba8e9adea, 0x404ad1751c749c29,
0xed7311bf23d7f185, 0xba4f6976b4acc43e,
0x32d7198d2bc39000, 0xee667019014d6e01,
0x494ef3e128d14c83, 0x1f95a152baecd6be,
0x201648dff1f483a5, 0x68c28550c8384af6,
0x5fc834a6824a7f48, 0x7cd06cb7365eaf28,
0xd82bbd95e9b30909, 0x234f0d1694c53f6d,
0xd2fb7f4a96d83f4a, 0xff0d5da83acac05e,
0xf8f6b97f5585080a, 0x74236084be57b95b,
0xa25e40c03bbc36ad, 0x6b6e5c14ce88465b,
0x4378ffe93e1528c5, 0x94ca92a17118e2d2,
}

14
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// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
/*
Package hash provides rolling hashes.
Rolling hashes have to be used for maintaining the positions of n-byte
sequences in the dictionary buffer.
The package provides currently the Rabin-Karp rolling hash and a Cyclic
Polynomial hash. Both support the Hashes method to be used with an interface.
*/
package hash

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// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package hash
// A is the default constant for Robin-Karp rolling hash. This is a random
// prime.
const A = 0x97b548add41d5da1
// RabinKarp supports the computation of a rolling hash.
type RabinKarp struct {
A uint64
// a^n
aOldest uint64
h uint64
p []byte
i int
}
// NewRabinKarp creates a new RabinKarp value. The argument n defines the
// length of the byte sequence to be hashed. The default constant will will be
// used.
func NewRabinKarp(n int) *RabinKarp {
return NewRabinKarpConst(n, A)
}
// NewRabinKarpConst creates a new RabinKarp value. The argument n defines the
// length of the byte sequence to be hashed. The argument a provides the
// constant used to compute the hash.
func NewRabinKarpConst(n int, a uint64) *RabinKarp {
if n <= 0 {
panic("number of bytes n must be positive")
}
aOldest := uint64(1)
// There are faster methods. For the small n required by the LZMA
// compressor O(n) is sufficient.
for i := 0; i < n; i++ {
aOldest *= a
}
return &RabinKarp{
A: a, aOldest: aOldest,
p: make([]byte, 0, n),
}
}
// Len returns the length of the byte sequence.
func (r *RabinKarp) Len() int {
return cap(r.p)
}
// RollByte computes the hash after x has been added.
func (r *RabinKarp) RollByte(x byte) uint64 {
if len(r.p) < cap(r.p) {
r.h += uint64(x)
r.h *= r.A
r.p = append(r.p, x)
} else {
r.h -= uint64(r.p[r.i]) * r.aOldest
r.h += uint64(x)
r.h *= r.A
r.p[r.i] = x
r.i = (r.i + 1) % cap(r.p)
}
return r.h
}

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// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package hash
// Roller provides an interface for rolling hashes. The hash value will become
// valid after hash has been called Len times.
type Roller interface {
Len() int
RollByte(x byte) uint64
}
// Hashes computes all hash values for the array p. Note that the state of the
// roller is changed.
func Hashes(r Roller, p []byte) []uint64 {
n := r.Len()
if len(p) < n {
return nil
}
h := make([]uint64, len(p)-n+1)
for i := 0; i < n-1; i++ {
r.RollByte(p[i])
}
for i := range h {
h[i] = r.RollByte(p[i+n-1])
}
return h
}

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// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Package xlog provides a simple logging package that allows to disable
// certain message categories. It defines a type, Logger, with multiple
// methods for formatting output. The package has also a predefined
// 'standard' Logger accessible through helper function Print[f|ln],
// Fatal[f|ln], Panic[f|ln], Warn[f|ln], Print[f|ln] and Debug[f|ln]
// that are easier to use then creating a Logger manually. That logger
// writes to standard error and prints the date and time of each logged
// message, which can be configured using the function SetFlags.
//
// The Fatal functions call os.Exit(1) after the message is output
// unless not suppressed by the flags. The Panic functions call panic
// after the writing the log message unless suppressed.
package xlog
import (
"fmt"
"io"
"os"
"runtime"
"sync"
"time"
)
// The flags define what information is prefixed to each log entry
// generated by the Logger. The Lno* versions allow the suppression of
// specific output. The bits are or'ed together to control what will be
// printed. There is no control over the order of the items printed and
// the format. The full format is:
//
// 2009-01-23 01:23:23.123123 /a/b/c/d.go:23: message
//
const (
Ldate = 1 << iota // the date: 2009-01-23
Ltime // the time: 01:23:23
Lmicroseconds // microsecond resolution: 01:23:23.123123
Llongfile // full file name and line number: /a/b/c/d.go:23
Lshortfile // final file name element and line number: d.go:23
Lnopanic // suppresses output from Panic[f|ln] but not the panic call
Lnofatal // suppresses output from Fatal[f|ln] but not the exit
Lnowarn // suppresses output from Warn[f|ln]
Lnoprint // suppresses output from Print[f|ln]
Lnodebug // suppresses output from Debug[f|ln]
// initial values for the standard logger
Lstdflags = Ldate | Ltime | Lnodebug
)
// A Logger represents an active logging object that generates lines of
// output to an io.Writer. Each logging operation if not suppressed
// makes a single call to the Writer's Write method. A Logger can be
// used simultaneously from multiple goroutines; it guarantees to
// serialize access to the Writer.
type Logger struct {
mu sync.Mutex // ensures atomic writes; and protects the following
// fields
prefix string // prefix to write at beginning of each line
flag int // properties
out io.Writer // destination for output
buf []byte // for accumulating text to write
}
// New creates a new Logger. The out argument sets the destination to
// which the log output will be written. The prefix appears at the
// beginning of each log line. The flag argument defines the logging
// properties.
func New(out io.Writer, prefix string, flag int) *Logger {
return &Logger{out: out, prefix: prefix, flag: flag}
}
// std is the standard logger used by the package scope functions.
var std = New(os.Stderr, "", Lstdflags)
// itoa converts the integer to ASCII. A negative widths will avoid
// zero-padding. The function supports only non-negative integers.
func itoa(buf *[]byte, i int, wid int) {
var u = uint(i)
if u == 0 && wid <= 1 {
*buf = append(*buf, '0')
return
}
var b [32]byte
bp := len(b)
for ; u > 0 || wid > 0; u /= 10 {
bp--
wid--
b[bp] = byte(u%10) + '0'
}
*buf = append(*buf, b[bp:]...)
}
// formatHeader puts the header into the buf field of the buffer.
func (l *Logger) formatHeader(t time.Time, file string, line int) {
l.buf = append(l.buf, l.prefix...)
if l.flag&(Ldate|Ltime|Lmicroseconds) != 0 {
if l.flag&Ldate != 0 {
year, month, day := t.Date()
itoa(&l.buf, year, 4)
l.buf = append(l.buf, '-')
itoa(&l.buf, int(month), 2)
l.buf = append(l.buf, '-')
itoa(&l.buf, day, 2)
l.buf = append(l.buf, ' ')
}
if l.flag&(Ltime|Lmicroseconds) != 0 {
hour, min, sec := t.Clock()
itoa(&l.buf, hour, 2)
l.buf = append(l.buf, ':')
itoa(&l.buf, min, 2)
l.buf = append(l.buf, ':')
itoa(&l.buf, sec, 2)
if l.flag&Lmicroseconds != 0 {
l.buf = append(l.buf, '.')
itoa(&l.buf, t.Nanosecond()/1e3, 6)
}
l.buf = append(l.buf, ' ')
}
}
if l.flag&(Lshortfile|Llongfile) != 0 {
if l.flag&Lshortfile != 0 {
short := file
for i := len(file) - 1; i > 0; i-- {
if file[i] == '/' {
short = file[i+1:]
break
}
}
file = short
}
l.buf = append(l.buf, file...)
l.buf = append(l.buf, ':')
itoa(&l.buf, line, -1)
l.buf = append(l.buf, ": "...)
}
}
func (l *Logger) output(calldepth int, now time.Time, s string) error {
var file string
var line int
if l.flag&(Lshortfile|Llongfile) != 0 {
l.mu.Unlock()
var ok bool
_, file, line, ok = runtime.Caller(calldepth)
if !ok {
file = "???"
line = 0
}
l.mu.Lock()
}
l.buf = l.buf[:0]
l.formatHeader(now, file, line)
l.buf = append(l.buf, s...)
if len(s) == 0 || s[len(s)-1] != '\n' {
l.buf = append(l.buf, '\n')
}
_, err := l.out.Write(l.buf)
return err
}
// Output writes the string s with the header controlled by the flags to
// the l.out writer. A newline will be appended if s doesn't end in a
// newline. Calldepth is used to recover the PC, although all current
// calls of Output use the call depth 2. Access to the function is serialized.
func (l *Logger) Output(calldepth, noflag int, v ...interface{}) error {
now := time.Now()
l.mu.Lock()
defer l.mu.Unlock()
if l.flag&noflag != 0 {
return nil
}
s := fmt.Sprint(v...)
return l.output(calldepth+1, now, s)
}
// Outputf works like output but formats the output like Printf.
func (l *Logger) Outputf(calldepth int, noflag int, format string, v ...interface{}) error {
now := time.Now()
l.mu.Lock()
defer l.mu.Unlock()
if l.flag&noflag != 0 {
return nil
}
s := fmt.Sprintf(format, v...)
return l.output(calldepth+1, now, s)
}
// Outputln works like output but formats the output like Println.
func (l *Logger) Outputln(calldepth int, noflag int, v ...interface{}) error {
now := time.Now()
l.mu.Lock()
defer l.mu.Unlock()
if l.flag&noflag != 0 {
return nil
}
s := fmt.Sprintln(v...)
return l.output(calldepth+1, now, s)
}
// Panic prints the message like Print and calls panic. The printing
// might be suppressed by the flag Lnopanic.
func (l *Logger) Panic(v ...interface{}) {
l.Output(2, Lnopanic, v...)
s := fmt.Sprint(v...)
panic(s)
}
// Panic prints the message like Print and calls panic. The printing
// might be suppressed by the flag Lnopanic.
func Panic(v ...interface{}) {
std.Output(2, Lnopanic, v...)
s := fmt.Sprint(v...)
panic(s)
}
// Panicf prints the message like Printf and calls panic. The printing
// might be suppressed by the flag Lnopanic.
func (l *Logger) Panicf(format string, v ...interface{}) {
l.Outputf(2, Lnopanic, format, v...)
s := fmt.Sprintf(format, v...)
panic(s)
}
// Panicf prints the message like Printf and calls panic. The printing
// might be suppressed by the flag Lnopanic.
func Panicf(format string, v ...interface{}) {
std.Outputf(2, Lnopanic, format, v...)
s := fmt.Sprintf(format, v...)
panic(s)
}
// Panicln prints the message like Println and calls panic. The printing
// might be suppressed by the flag Lnopanic.
func (l *Logger) Panicln(v ...interface{}) {
l.Outputln(2, Lnopanic, v...)
s := fmt.Sprintln(v...)
panic(s)
}
// Panicln prints the message like Println and calls panic. The printing
// might be suppressed by the flag Lnopanic.
func Panicln(v ...interface{}) {
std.Outputln(2, Lnopanic, v...)
s := fmt.Sprintln(v...)
panic(s)
}
// Fatal prints the message like Print and calls os.Exit(1). The
// printing might be suppressed by the flag Lnofatal.
func (l *Logger) Fatal(v ...interface{}) {
l.Output(2, Lnofatal, v...)
os.Exit(1)
}
// Fatal prints the message like Print and calls os.Exit(1). The
// printing might be suppressed by the flag Lnofatal.
func Fatal(v ...interface{}) {
std.Output(2, Lnofatal, v...)
os.Exit(1)
}
// Fatalf prints the message like Printf and calls os.Exit(1). The
// printing might be suppressed by the flag Lnofatal.
func (l *Logger) Fatalf(format string, v ...interface{}) {
l.Outputf(2, Lnofatal, format, v...)
os.Exit(1)
}
// Fatalf prints the message like Printf and calls os.Exit(1). The
// printing might be suppressed by the flag Lnofatal.
func Fatalf(format string, v ...interface{}) {
std.Outputf(2, Lnofatal, format, v...)
os.Exit(1)
}
// Fatalln prints the message like Println and calls os.Exit(1). The
// printing might be suppressed by the flag Lnofatal.
func (l *Logger) Fatalln(format string, v ...interface{}) {
l.Outputln(2, Lnofatal, v...)
os.Exit(1)
}
// Fatalln prints the message like Println and calls os.Exit(1). The
// printing might be suppressed by the flag Lnofatal.
func Fatalln(format string, v ...interface{}) {
std.Outputln(2, Lnofatal, v...)
os.Exit(1)
}
// Warn prints the message like Print. The printing might be suppressed
// by the flag Lnowarn.
func (l *Logger) Warn(v ...interface{}) {
l.Output(2, Lnowarn, v...)
}
// Warn prints the message like Print. The printing might be suppressed
// by the flag Lnowarn.
func Warn(v ...interface{}) {
std.Output(2, Lnowarn, v...)
}
// Warnf prints the message like Printf. The printing might be suppressed
// by the flag Lnowarn.
func (l *Logger) Warnf(format string, v ...interface{}) {
l.Outputf(2, Lnowarn, format, v...)
}
// Warnf prints the message like Printf. The printing might be suppressed
// by the flag Lnowarn.
func Warnf(format string, v ...interface{}) {
std.Outputf(2, Lnowarn, format, v...)
}
// Warnln prints the message like Println. The printing might be suppressed
// by the flag Lnowarn.
func (l *Logger) Warnln(v ...interface{}) {
l.Outputln(2, Lnowarn, v...)
}
// Warnln prints the message like Println. The printing might be suppressed
// by the flag Lnowarn.
func Warnln(v ...interface{}) {
std.Outputln(2, Lnowarn, v...)
}
// Print prints the message like fmt.Print. The printing might be suppressed
// by the flag Lnoprint.
func (l *Logger) Print(v ...interface{}) {
l.Output(2, Lnoprint, v...)
}
// Print prints the message like fmt.Print. The printing might be suppressed
// by the flag Lnoprint.
func Print(v ...interface{}) {
std.Output(2, Lnoprint, v...)
}
// Printf prints the message like fmt.Printf. The printing might be suppressed
// by the flag Lnoprint.
func (l *Logger) Printf(format string, v ...interface{}) {
l.Outputf(2, Lnoprint, format, v...)
}
// Printf prints the message like fmt.Printf. The printing might be suppressed
// by the flag Lnoprint.
func Printf(format string, v ...interface{}) {
std.Outputf(2, Lnoprint, format, v...)
}
// Println prints the message like fmt.Println. The printing might be
// suppressed by the flag Lnoprint.
func (l *Logger) Println(v ...interface{}) {
l.Outputln(2, Lnoprint, v...)
}
// Println prints the message like fmt.Println. The printing might be
// suppressed by the flag Lnoprint.
func Println(v ...interface{}) {
std.Outputln(2, Lnoprint, v...)
}
// Debug prints the message like Print. The printing might be suppressed
// by the flag Lnodebug.
func (l *Logger) Debug(v ...interface{}) {
l.Output(2, Lnodebug, v...)
}
// Debug prints the message like Print. The printing might be suppressed
// by the flag Lnodebug.
func Debug(v ...interface{}) {
std.Output(2, Lnodebug, v...)
}
// Debugf prints the message like Printf. The printing might be suppressed
// by the flag Lnodebug.
func (l *Logger) Debugf(format string, v ...interface{}) {
l.Outputf(2, Lnodebug, format, v...)
}
// Debugf prints the message like Printf. The printing might be suppressed
// by the flag Lnodebug.
func Debugf(format string, v ...interface{}) {
std.Outputf(2, Lnodebug, format, v...)
}
// Debugln prints the message like Println. The printing might be suppressed
// by the flag Lnodebug.
func (l *Logger) Debugln(v ...interface{}) {
l.Outputln(2, Lnodebug, v...)
}
// Debugln prints the message like Println. The printing might be suppressed
// by the flag Lnodebug.
func Debugln(v ...interface{}) {
std.Outputln(2, Lnodebug, v...)
}
// Flags returns the current flags used by the logger.
func (l *Logger) Flags() int {
l.mu.Lock()
defer l.mu.Unlock()
return l.flag
}
// Flags returns the current flags used by the standard logger.
func Flags() int {
return std.Flags()
}
// SetFlags sets the flags of the logger.
func (l *Logger) SetFlags(flag int) {
l.mu.Lock()
defer l.mu.Unlock()
l.flag = flag
}
// SetFlags sets the flags for the standard logger.
func SetFlags(flag int) {
std.SetFlags(flag)
}
// Prefix returns the prefix used by the logger.
func (l *Logger) Prefix() string {
l.mu.Lock()
defer l.mu.Unlock()
return l.prefix
}
// Prefix returns the prefix used by the standard logger of the package.
func Prefix() string {
return std.Prefix()
}
// SetPrefix sets the prefix for the logger.
func (l *Logger) SetPrefix(prefix string) {
l.mu.Lock()
defer l.mu.Unlock()
l.prefix = prefix
}
// SetPrefix sets the prefix of the standard logger of the package.
func SetPrefix(prefix string) {
std.SetPrefix(prefix)
}
// SetOutput sets the output of the logger.
func (l *Logger) SetOutput(w io.Writer) {
l.mu.Lock()
defer l.mu.Unlock()
l.out = w
}
// SetOutput sets the output for the standard logger of the package.
func SetOutput(w io.Writer) {
std.SetOutput(w)
}

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// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package lzma
import (
"bufio"
"errors"
"fmt"
"io"
"unicode"
)
// node represents a node in the binary tree.
type node struct {
// x is the search value
x uint32
// p parent node
p uint32
// l left child
l uint32
// r right child
r uint32
}
// wordLen is the number of bytes represented by the v field of a node.
const wordLen = 4
// binTree supports the identification of the next operation based on a
// binary tree.
//
// Nodes will be identified by their index into the ring buffer.
type binTree struct {
dict *encoderDict
// ring buffer of nodes
node []node
// absolute offset of the entry for the next node. Position 4
// byte larger.
hoff int64
// front position in the node ring buffer
front uint32
// index of the root node
root uint32
// current x value
x uint32
// preallocated array
data []byte
}
// null represents the nonexistent index. We can't use zero because it
// would always exist or we would need to decrease the index for each
// reference.
const null uint32 = 1<<32 - 1
// newBinTree initializes the binTree structure. The capacity defines
// the size of the buffer and defines the maximum distance for which
// matches will be found.
func newBinTree(capacity int) (t *binTree, err error) {
if capacity < 1 {
return nil, errors.New(
"newBinTree: capacity must be larger than zero")
}
if int64(capacity) >= int64(null) {
return nil, errors.New(
"newBinTree: capacity must less 2^{32}-1")
}
t = &binTree{
node: make([]node, capacity),
hoff: -int64(wordLen),
root: null,
data: make([]byte, maxMatchLen),
}
return t, nil
}
func (t *binTree) SetDict(d *encoderDict) { t.dict = d }
// WriteByte writes a single byte into the binary tree.
func (t *binTree) WriteByte(c byte) error {
t.x = (t.x << 8) | uint32(c)
t.hoff++
if t.hoff < 0 {
return nil
}
v := t.front
if int64(v) < t.hoff {
// We are overwriting old nodes stored in the tree.
t.remove(v)
}
t.node[v].x = t.x
t.add(v)
t.front++
if int64(t.front) >= int64(len(t.node)) {
t.front = 0
}
return nil
}
// Writes writes a sequence of bytes into the binTree structure.
func (t *binTree) Write(p []byte) (n int, err error) {
for _, c := range p {
t.WriteByte(c)
}
return len(p), nil
}
// add puts the node v into the tree. The node must not be part of the
// tree before.
func (t *binTree) add(v uint32) {
vn := &t.node[v]
// Set left and right to null indices.
vn.l, vn.r = null, null
// If the binary tree is empty make v the root.
if t.root == null {
t.root = v
vn.p = null
return
}
x := vn.x
p := t.root
// Search for the right leave link and add the new node.
for {
pn := &t.node[p]
if x <= pn.x {
if pn.l == null {
pn.l = v
vn.p = p
return
}
p = pn.l
} else {
if pn.r == null {
pn.r = v
vn.p = p
return
}
p = pn.r
}
}
}
// parent returns the parent node index of v and the pointer to v value
// in the parent.
func (t *binTree) parent(v uint32) (p uint32, ptr *uint32) {
if t.root == v {
return null, &t.root
}
p = t.node[v].p
if t.node[p].l == v {
ptr = &t.node[p].l
} else {
ptr = &t.node[p].r
}
return
}
// Remove node v.
func (t *binTree) remove(v uint32) {
vn := &t.node[v]
p, ptr := t.parent(v)
l, r := vn.l, vn.r
if l == null {
// Move the right child up.
*ptr = r
if r != null {
t.node[r].p = p
}
return
}
if r == null {
// Move the left child up.
*ptr = l
t.node[l].p = p
return
}
// Search the in-order predecessor u.
un := &t.node[l]
ur := un.r
if ur == null {
// In order predecessor is l. Move it up.
un.r = r
t.node[r].p = l
un.p = p
*ptr = l
return
}
var u uint32
for {
// Look for the max value in the tree where l is root.
u = ur
ur = t.node[u].r
if ur == null {
break
}
}
// replace u with ul
un = &t.node[u]
ul := un.l
up := un.p
t.node[up].r = ul
if ul != null {
t.node[ul].p = up
}
// replace v by u
un.l, un.r = l, r
t.node[l].p = u
t.node[r].p = u
*ptr = u
un.p = p
}
// search looks for the node that have the value x or for the nodes that
// brace it. The node highest in the tree with the value x will be
// returned. All other nodes with the same value live in left subtree of
// the returned node.
func (t *binTree) search(v uint32, x uint32) (a, b uint32) {
a, b = null, null
if v == null {
return
}
for {
vn := &t.node[v]
if x <= vn.x {
if x == vn.x {
return v, v
}
b = v
if vn.l == null {
return
}
v = vn.l
} else {
a = v
if vn.r == null {
return
}
v = vn.r
}
}
}
// max returns the node with maximum value in the subtree with v as
// root.
func (t *binTree) max(v uint32) uint32 {
if v == null {
return null
}
for {
r := t.node[v].r
if r == null {
return v
}
v = r
}
}
// min returns the node with the minimum value in the subtree with v as
// root.
func (t *binTree) min(v uint32) uint32 {
if v == null {
return null
}
for {
l := t.node[v].l
if l == null {
return v
}
v = l
}
}
// pred returns the in-order predecessor of node v.
func (t *binTree) pred(v uint32) uint32 {
if v == null {
return null
}
u := t.max(t.node[v].l)
if u != null {
return u
}
for {
p := t.node[v].p
if p == null {
return null
}
if t.node[p].r == v {
return p
}
v = p
}
}
// succ returns the in-order successor of node v.
func (t *binTree) succ(v uint32) uint32 {
if v == null {
return null
}
u := t.min(t.node[v].r)
if u != null {
return u
}
for {
p := t.node[v].p
if p == null {
return null
}
if t.node[p].l == v {
return p
}
v = p
}
}
// xval converts the first four bytes of a into an 32-bit unsigned
// integer in big-endian order.
func xval(a []byte) uint32 {
var x uint32
switch len(a) {
default:
x |= uint32(a[3])
fallthrough
case 3:
x |= uint32(a[2]) << 8
fallthrough
case 2:
x |= uint32(a[1]) << 16
fallthrough
case 1:
x |= uint32(a[0]) << 24
case 0:
}
return x
}
// dumpX converts value x into a four-letter string.
func dumpX(x uint32) string {
a := make([]byte, 4)
for i := 0; i < 4; i++ {
c := byte(x >> uint((3-i)*8))
if unicode.IsGraphic(rune(c)) {
a[i] = c
} else {
a[i] = '.'
}
}
return string(a)
}
// dumpNode writes a representation of the node v into the io.Writer.
func (t *binTree) dumpNode(w io.Writer, v uint32, indent int) {
if v == null {
return
}
vn := &t.node[v]
t.dumpNode(w, vn.r, indent+2)
for i := 0; i < indent; i++ {
fmt.Fprint(w, " ")
}
if vn.p == null {
fmt.Fprintf(w, "node %d %q parent null\n", v, dumpX(vn.x))
} else {
fmt.Fprintf(w, "node %d %q parent %d\n", v, dumpX(vn.x), vn.p)
}
t.dumpNode(w, vn.l, indent+2)
}
// dump prints a representation of the binary tree into the writer.
func (t *binTree) dump(w io.Writer) error {
bw := bufio.NewWriter(w)
t.dumpNode(bw, t.root, 0)
return bw.Flush()
}
func (t *binTree) distance(v uint32) int {
dist := int(t.front) - int(v)
if dist <= 0 {
dist += len(t.node)
}
return dist
}
type matchParams struct {
rep [4]uint32
// length when match will be accepted
nAccept int
// nodes to check
check int
// finish if length get shorter
stopShorter bool
}
func (t *binTree) match(m match, distIter func() (int, bool), p matchParams,
) (r match, checked int, accepted bool) {
buf := &t.dict.buf
for {
if checked >= p.check {
return m, checked, true
}
dist, ok := distIter()
if !ok {
return m, checked, false
}
checked++
if m.n > 0 {
i := buf.rear - dist + m.n - 1
if i < 0 {
i += len(buf.data)
} else if i >= len(buf.data) {
i -= len(buf.data)
}
if buf.data[i] != t.data[m.n-1] {
if p.stopShorter {
return m, checked, false
}
continue
}
}
n := buf.matchLen(dist, t.data)
switch n {
case 0:
if p.stopShorter {
return m, checked, false
}
continue
case 1:
if uint32(dist-minDistance) != p.rep[0] {
continue
}
}
if n < m.n || (n == m.n && int64(dist) >= m.distance) {
continue
}
m = match{int64(dist), n}
if n >= p.nAccept {
return m, checked, true
}
}
}
func (t *binTree) NextOp(rep [4]uint32) operation {
// retrieve maxMatchLen data
n, _ := t.dict.buf.Peek(t.data[:maxMatchLen])
if n == 0 {
panic("no data in buffer")
}
t.data = t.data[:n]
var (
m match
x, u, v uint32
iterPred, iterSucc func() (int, bool)
)
p := matchParams{
rep: rep,
nAccept: maxMatchLen,
check: 32,
}
i := 4
iterSmall := func() (dist int, ok bool) {
i--
if i <= 0 {
return 0, false
}
return i, true
}
m, checked, accepted := t.match(m, iterSmall, p)
if accepted {
goto end
}
p.check -= checked
x = xval(t.data)
u, v = t.search(t.root, x)
if u == v && len(t.data) == 4 {
iter := func() (dist int, ok bool) {
if u == null {
return 0, false
}
dist = t.distance(u)
u, v = t.search(t.node[u].l, x)
if u != v {
u = null
}
return dist, true
}
m, _, _ = t.match(m, iter, p)
goto end
}
p.stopShorter = true
iterSucc = func() (dist int, ok bool) {
if v == null {
return 0, false
}
dist = t.distance(v)
v = t.succ(v)
return dist, true
}
m, checked, accepted = t.match(m, iterSucc, p)
if accepted {
goto end
}
p.check -= checked
iterPred = func() (dist int, ok bool) {
if u == null {
return 0, false
}
dist = t.distance(u)
u = t.pred(u)
return dist, true
}
m, _, _ = t.match(m, iterPred, p)
end:
if m.n == 0 {
return lit{t.data[0]}
}
return m
}

45
vendor/github.com/ulikunitz/xz/lzma/bitops.go generated vendored Normal file
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// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package lzma
/* Naming conventions follows the CodeReviewComments in the Go Wiki. */
// ntz32Const is used by the functions NTZ and NLZ.
const ntz32Const = 0x04d7651f
// ntz32Table is a helper table for de Bruijn algorithm by Danny Dubé.
// See Henry S. Warren, Jr. "Hacker's Delight" section 5-1 figure 5-26.
var ntz32Table = [32]int8{
0, 1, 2, 24, 3, 19, 6, 25,
22, 4, 20, 10, 16, 7, 12, 26,
31, 23, 18, 5, 21, 9, 15, 11,
30, 17, 8, 14, 29, 13, 28, 27,
}
// ntz32 computes the number of trailing zeros for an unsigned 32-bit integer.
func ntz32(x uint32) int {
if x == 0 {
return 32
}
x = (x & -x) * ntz32Const
return int(ntz32Table[x>>27])
}
// nlz32 computes the number of leading zeros for an unsigned 32-bit integer.
func nlz32(x uint32) int {
// Smear left most bit to the right
x |= x >> 1
x |= x >> 2
x |= x >> 4
x |= x >> 8
x |= x >> 16
// Use ntz mechanism to calculate nlz.
x++
if x == 0 {
return 0
}
x *= ntz32Const
return 32 - int(ntz32Table[x>>27])
}

39
vendor/github.com/ulikunitz/xz/lzma/breader.go generated vendored Normal file
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// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package lzma
import (
"errors"
"io"
)
// breader provides the ReadByte function for a Reader. It doesn't read
// more data from the reader than absolutely necessary.
type breader struct {
io.Reader
// helper slice to save allocations
p []byte
}
// ByteReader converts an io.Reader into an io.ByteReader.
func ByteReader(r io.Reader) io.ByteReader {
br, ok := r.(io.ByteReader)
if !ok {
return &breader{r, make([]byte, 1)}
}
return br
}
// ReadByte read byte function.
func (r *breader) ReadByte() (c byte, err error) {
n, err := r.Reader.Read(r.p)
if n < 1 {
if err == nil {
err = errors.New("breader.ReadByte: no data")
}
return 0, err
}
return r.p[0], nil
}

171
vendor/github.com/ulikunitz/xz/lzma/buffer.go generated vendored Normal file
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// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package lzma
import (
"errors"
)
// buffer provides a circular buffer of bytes. If the front index equals
// the rear index the buffer is empty. As a consequence front cannot be
// equal rear for a full buffer. So a full buffer has a length that is
// one byte less the the length of the data slice.
type buffer struct {
data []byte
front int
rear int
}
// newBuffer creates a buffer with the given size.
func newBuffer(size int) *buffer {
return &buffer{data: make([]byte, size+1)}
}
// Cap returns the capacity of the buffer.
func (b *buffer) Cap() int {
return len(b.data) - 1
}
// Resets the buffer. The front and rear index are set to zero.
func (b *buffer) Reset() {
b.front = 0
b.rear = 0
}
// Buffered returns the number of bytes buffered.
func (b *buffer) Buffered() int {
delta := b.front - b.rear
if delta < 0 {
delta += len(b.data)
}
return delta
}
// Available returns the number of bytes available for writing.
func (b *buffer) Available() int {
delta := b.rear - 1 - b.front
if delta < 0 {
delta += len(b.data)
}
return delta
}
// addIndex adds a non-negative integer to the index i and returns the
// resulting index. The function takes care of wrapping the index as
// well as potential overflow situations.
func (b *buffer) addIndex(i int, n int) int {
// subtraction of len(b.data) prevents overflow
i += n - len(b.data)
if i < 0 {
i += len(b.data)
}
return i
}
// Read reads bytes from the buffer into p and returns the number of
// bytes read. The function never returns an error but might return less
// data than requested.
func (b *buffer) Read(p []byte) (n int, err error) {
n, err = b.Peek(p)
b.rear = b.addIndex(b.rear, n)
return n, err
}
// Peek reads bytes from the buffer into p without changing the buffer.
// Peek will never return an error but might return less data than
// requested.
func (b *buffer) Peek(p []byte) (n int, err error) {
m := b.Buffered()
n = len(p)
if m < n {
n = m
p = p[:n]
}
k := copy(p, b.data[b.rear:])
if k < n {
copy(p[k:], b.data)
}
return n, nil
}
// Discard skips the n next bytes to read from the buffer, returning the
// bytes discarded.
//
// If Discards skips fewer than n bytes, it returns an error.
func (b *buffer) Discard(n int) (discarded int, err error) {
if n < 0 {
return 0, errors.New("buffer.Discard: negative argument")
}
m := b.Buffered()
if m < n {
n = m
err = errors.New(
"buffer.Discard: discarded less bytes then requested")
}
b.rear = b.addIndex(b.rear, n)
return n, err
}
// ErrNoSpace indicates that there is insufficient space for the Write
// operation.
var ErrNoSpace = errors.New("insufficient space")
// Write puts data into the buffer. If less bytes are written than
// requested ErrNoSpace is returned.
func (b *buffer) Write(p []byte) (n int, err error) {
m := b.Available()
n = len(p)
if m < n {
n = m
p = p[:m]
err = ErrNoSpace
}
k := copy(b.data[b.front:], p)
if k < n {
copy(b.data, p[k:])
}
b.front = b.addIndex(b.front, n)
return n, err
}
// WriteByte writes a single byte into the buffer. The error ErrNoSpace
// is returned if no single byte is available in the buffer for writing.
func (b *buffer) WriteByte(c byte) error {
if b.Available() < 1 {
return ErrNoSpace
}
b.data[b.front] = c
b.front = b.addIndex(b.front, 1)
return nil
}
// prefixLen returns the length of the common prefix of a and b.
func prefixLen(a, b []byte) int {
if len(a) > len(b) {
a, b = b, a
}
for i, c := range a {
if b[i] != c {
return i
}
}
return len(a)
}
// matchLen returns the length of the common prefix for the given
// distance from the rear and the byte slice p.
func (b *buffer) matchLen(distance int, p []byte) int {
var n int
i := b.rear - distance
if i < 0 {
if n = prefixLen(p, b.data[len(b.data)+i:]); n < -i {
return n
}
p = p[n:]
i = 0
}
n += prefixLen(p, b.data[i:])
return n
}

37
vendor/github.com/ulikunitz/xz/lzma/bytewriter.go generated vendored Normal file
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// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package lzma
import (
"errors"
"io"
)
// ErrLimit indicates that the limit of the LimitedByteWriter has been
// reached.
var ErrLimit = errors.New("limit reached")
// LimitedByteWriter provides a byte writer that can be written until a
// limit is reached. The field N provides the number of remaining
// bytes.
type LimitedByteWriter struct {
BW io.ByteWriter
N int64
}
// WriteByte writes a single byte to the limited byte writer. It returns
// ErrLimit if the limit has been reached. If the byte is successfully
// written the field N of the LimitedByteWriter will be decremented by
// one.
func (l *LimitedByteWriter) WriteByte(c byte) error {
if l.N <= 0 {
return ErrLimit
}
if err := l.BW.WriteByte(c); err != nil {
return err
}
l.N--
return nil
}

277
vendor/github.com/ulikunitz/xz/lzma/decoder.go generated vendored Normal file
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// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package lzma
import (
"errors"
"fmt"
"io"
)
// decoder decodes a raw LZMA stream without any header.
type decoder struct {
// dictionary; the rear pointer of the buffer will be used for
// reading the data.
Dict *decoderDict
// decoder state
State *state
// range decoder
rd *rangeDecoder
// start stores the head value of the dictionary for the LZMA
// stream
start int64
// size of uncompressed data
size int64
// end-of-stream encountered
eos bool
// EOS marker found
eosMarker bool
}
// newDecoder creates a new decoder instance. The parameter size provides
// the expected byte size of the decompressed data. If the size is
// unknown use a negative value. In that case the decoder will look for
// a terminating end-of-stream marker.
func newDecoder(br io.ByteReader, state *state, dict *decoderDict, size int64) (d *decoder, err error) {
rd, err := newRangeDecoder(br)
if err != nil {
return nil, err
}
d = &decoder{
State: state,
Dict: dict,
rd: rd,
size: size,
start: dict.pos(),
}
return d, nil
}
// Reopen restarts the decoder with a new byte reader and a new size. Reopen
// resets the Decompressed counter to zero.
func (d *decoder) Reopen(br io.ByteReader, size int64) error {
var err error
if d.rd, err = newRangeDecoder(br); err != nil {
return err
}
d.start = d.Dict.pos()
d.size = size
d.eos = false
return nil
}
// decodeLiteral decodes a single literal from the LZMA stream.
func (d *decoder) decodeLiteral() (op operation, err error) {
litState := d.State.litState(d.Dict.byteAt(1), d.Dict.head)
match := d.Dict.byteAt(int(d.State.rep[0]) + 1)
s, err := d.State.litCodec.Decode(d.rd, d.State.state, match, litState)
if err != nil {
return nil, err
}
return lit{s}, nil
}
// errEOS indicates that an EOS marker has been found.
var errEOS = errors.New("EOS marker found")
// readOp decodes the next operation from the compressed stream. It
// returns the operation. If an explicit end of stream marker is
// identified the eos error is returned.
func (d *decoder) readOp() (op operation, err error) {
// Value of the end of stream (EOS) marker
const eosDist = 1<<32 - 1
state, state2, posState := d.State.states(d.Dict.head)
b, err := d.State.isMatch[state2].Decode(d.rd)
if err != nil {
return nil, err
}
if b == 0 {
// literal
op, err := d.decodeLiteral()
if err != nil {
return nil, err
}
d.State.updateStateLiteral()
return op, nil
}
b, err = d.State.isRep[state].Decode(d.rd)
if err != nil {
return nil, err
}
if b == 0 {
// simple match
d.State.rep[3], d.State.rep[2], d.State.rep[1] =
d.State.rep[2], d.State.rep[1], d.State.rep[0]
d.State.updateStateMatch()
// The length decoder returns the length offset.
n, err := d.State.lenCodec.Decode(d.rd, posState)
if err != nil {
return nil, err
}
// The dist decoder returns the distance offset. The actual
// distance is 1 higher.
d.State.rep[0], err = d.State.distCodec.Decode(d.rd, n)
if err != nil {
return nil, err
}
if d.State.rep[0] == eosDist {
d.eosMarker = true
return nil, errEOS
}
op = match{n: int(n) + minMatchLen,
distance: int64(d.State.rep[0]) + minDistance}
return op, nil
}
b, err = d.State.isRepG0[state].Decode(d.rd)
if err != nil {
return nil, err
}
dist := d.State.rep[0]
if b == 0 {
// rep match 0
b, err = d.State.isRepG0Long[state2].Decode(d.rd)
if err != nil {
return nil, err
}
if b == 0 {
d.State.updateStateShortRep()
op = match{n: 1, distance: int64(dist) + minDistance}
return op, nil
}
} else {
b, err = d.State.isRepG1[state].Decode(d.rd)
if err != nil {
return nil, err
}
if b == 0 {
dist = d.State.rep[1]
} else {
b, err = d.State.isRepG2[state].Decode(d.rd)
if err != nil {
return nil, err
}
if b == 0 {
dist = d.State.rep[2]
} else {
dist = d.State.rep[3]
d.State.rep[3] = d.State.rep[2]
}
d.State.rep[2] = d.State.rep[1]
}
d.State.rep[1] = d.State.rep[0]
d.State.rep[0] = dist
}
n, err := d.State.repLenCodec.Decode(d.rd, posState)
if err != nil {
return nil, err
}
d.State.updateStateRep()
op = match{n: int(n) + minMatchLen, distance: int64(dist) + minDistance}
return op, nil
}
// apply takes the operation and transforms the decoder dictionary accordingly.
func (d *decoder) apply(op operation) error {
var err error
switch x := op.(type) {
case match:
err = d.Dict.writeMatch(x.distance, x.n)
case lit:
err = d.Dict.WriteByte(x.b)
default:
panic("op is neither a match nor a literal")
}
return err
}
// decompress fills the dictionary unless no space for new data is
// available. If the end of the LZMA stream has been reached io.EOF will
// be returned.
func (d *decoder) decompress() error {
if d.eos {
return io.EOF
}
for d.Dict.Available() >= maxMatchLen {
op, err := d.readOp()
switch err {
case nil:
break
case errEOS:
d.eos = true
if !d.rd.possiblyAtEnd() {
return errDataAfterEOS
}
if d.size >= 0 && d.size != d.Decompressed() {
return errSize
}
return io.EOF
case io.EOF:
d.eos = true
return io.ErrUnexpectedEOF
default:
return err
}
if err = d.apply(op); err != nil {
return err
}
if d.size >= 0 && d.Decompressed() >= d.size {
d.eos = true
if d.Decompressed() > d.size {
return errSize
}
if !d.rd.possiblyAtEnd() {
switch _, err = d.readOp(); err {
case nil:
return errSize
case io.EOF:
return io.ErrUnexpectedEOF
case errEOS:
break
default:
return err
}
}
return io.EOF
}
}
return nil
}
// Errors that may be returned while decoding data.
var (
errDataAfterEOS = errors.New("lzma: data after end of stream marker")
errSize = errors.New("lzma: wrong uncompressed data size")
)
// Read reads data from the buffer. If no more data is available io.EOF is
// returned.
func (d *decoder) Read(p []byte) (n int, err error) {
var k int
for {
// Read of decoder dict never returns an error.
k, err = d.Dict.Read(p[n:])
if err != nil {
panic(fmt.Errorf("dictionary read error %s", err))
}
if k == 0 && d.eos {
return n, io.EOF
}
n += k
if n >= len(p) {
return n, nil
}
if err = d.decompress(); err != nil && err != io.EOF {
return n, err
}
}
}
// Decompressed returns the number of bytes decompressed by the decoder.
func (d *decoder) Decompressed() int64 {
return d.Dict.pos() - d.start
}

135
vendor/github.com/ulikunitz/xz/lzma/decoderdict.go generated vendored Normal file
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// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package lzma
import (
"errors"
"fmt"
)
// decoderDict provides the dictionary for the decoder. The whole
// dictionary is used as reader buffer.
type decoderDict struct {
buf buffer
head int64
}
// newDecoderDict creates a new decoder dictionary. The whole dictionary
// will be used as reader buffer.
func newDecoderDict(dictCap int) (d *decoderDict, err error) {
// lower limit supports easy test cases
if !(1 <= dictCap && int64(dictCap) <= MaxDictCap) {
return nil, errors.New("lzma: dictCap out of range")
}
d = &decoderDict{buf: *newBuffer(dictCap)}
return d, nil
}
// Reset clears the dictionary. The read buffer is not changed, so the
// buffered data can still be read.
func (d *decoderDict) Reset() {
d.head = 0
}
// WriteByte writes a single byte into the dictionary. It is used to
// write literals into the dictionary.
func (d *decoderDict) WriteByte(c byte) error {
if err := d.buf.WriteByte(c); err != nil {
return err
}
d.head++
return nil
}
// pos returns the position of the dictionary head.
func (d *decoderDict) pos() int64 { return d.head }
// dictLen returns the actual length of the dictionary.
func (d *decoderDict) dictLen() int {
capacity := d.buf.Cap()
if d.head >= int64(capacity) {
return capacity
}
return int(d.head)
}
// byteAt returns a byte stored in the dictionary. If the distance is
// non-positive or exceeds the current length of the dictionary the zero
// byte is returned.
func (d *decoderDict) byteAt(dist int) byte {
if !(0 < dist && dist <= d.dictLen()) {
return 0
}
i := d.buf.front - dist
if i < 0 {
i += len(d.buf.data)
}
return d.buf.data[i]
}
// writeMatch writes the match at the top of the dictionary. The given
// distance must point in the current dictionary and the length must not
// exceed the maximum length 273 supported in LZMA.
//
// The error value ErrNoSpace indicates that no space is available in
// the dictionary for writing. You need to read from the dictionary
// first.
func (d *decoderDict) writeMatch(dist int64, length int) error {
if !(0 < dist && dist <= int64(d.dictLen())) {
return errors.New("writeMatch: distance out of range")
}
if !(0 < length && length <= maxMatchLen) {
return errors.New("writeMatch: length out of range")
}
if length > d.buf.Available() {
return ErrNoSpace
}
d.head += int64(length)
i := d.buf.front - int(dist)
if i < 0 {
i += len(d.buf.data)
}
for length > 0 {
var p []byte
if i >= d.buf.front {
p = d.buf.data[i:]
i = 0
} else {
p = d.buf.data[i:d.buf.front]
i = d.buf.front
}
if len(p) > length {
p = p[:length]
}
if _, err := d.buf.Write(p); err != nil {
panic(fmt.Errorf("d.buf.Write returned error %s", err))
}
length -= len(p)
}
return nil
}
// Write writes the given bytes into the dictionary and advances the
// head.
func (d *decoderDict) Write(p []byte) (n int, err error) {
n, err = d.buf.Write(p)
d.head += int64(n)
return n, err
}
// Available returns the number of available bytes for writing into the
// decoder dictionary.
func (d *decoderDict) Available() int { return d.buf.Available() }
// Read reads data from the buffer contained in the decoder dictionary.
func (d *decoderDict) Read(p []byte) (n int, err error) { return d.buf.Read(p) }
// Buffered returns the number of bytes currently buffered in the
// decoder dictionary.
func (d *decoderDict) buffered() int { return d.buf.Buffered() }
// Peek gets data from the buffer without advancing the rear index.
func (d *decoderDict) peek(p []byte) (n int, err error) { return d.buf.Peek(p) }

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// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package lzma
import "fmt"
// directCodec allows the encoding and decoding of values with a fixed number
// of bits. The number of bits must be in the range [1,32].
type directCodec byte
// makeDirectCodec creates a directCodec. The function panics if the number of
// bits is not in the range [1,32].
func makeDirectCodec(bits int) directCodec {
if !(1 <= bits && bits <= 32) {
panic(fmt.Errorf("bits=%d out of range", bits))
}
return directCodec(bits)
}
// Bits returns the number of bits supported by this codec.
func (dc directCodec) Bits() int {
return int(dc)
}
// Encode uses the range encoder to encode a value with the fixed number of
// bits. The most-significant bit is encoded first.
func (dc directCodec) Encode(e *rangeEncoder, v uint32) error {
for i := int(dc) - 1; i >= 0; i-- {
if err := e.DirectEncodeBit(v >> uint(i)); err != nil {
return err
}
}
return nil
}
// Decode uses the range decoder to decode a value with the given number of
// given bits. The most-significant bit is decoded first.
func (dc directCodec) Decode(d *rangeDecoder) (v uint32, err error) {
for i := int(dc) - 1; i >= 0; i-- {
x, err := d.DirectDecodeBit()
if err != nil {
return 0, err
}
v = (v << 1) | x
}
return v, nil
}

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// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package lzma
// Constants used by the distance codec.
const (
// minimum supported distance
minDistance = 1
// maximum supported distance, value is used for the eos marker.
maxDistance = 1 << 32
// number of the supported len states
lenStates = 4
// start for the position models
startPosModel = 4
// first index with align bits support
endPosModel = 14
// bits for the position slots
posSlotBits = 6
// number of align bits
alignBits = 4
// maximum position slot
maxPosSlot = 63
)
// distCodec provides encoding and decoding of distance values.
type distCodec struct {
posSlotCodecs [lenStates]treeCodec
posModel [endPosModel - startPosModel]treeReverseCodec
alignCodec treeReverseCodec
}
// deepcopy initializes dc as deep copy of the source.
func (dc *distCodec) deepcopy(src *distCodec) {
if dc == src {
return
}
for i := range dc.posSlotCodecs {
dc.posSlotCodecs[i].deepcopy(&src.posSlotCodecs[i])
}
for i := range dc.posModel {
dc.posModel[i].deepcopy(&src.posModel[i])
}
dc.alignCodec.deepcopy(&src.alignCodec)
}
// distBits returns the number of bits required to encode dist.
func distBits(dist uint32) int {
if dist < startPosModel {
return 6
}
// slot s > 3, dist d
// s = 2(bits(d)-1) + bit(d, bits(d)-2)
// s>>1 = bits(d)-1
// bits(d) = 32-nlz32(d)
// s>>1=31-nlz32(d)
// n = 5 + (s>>1) = 36 - nlz32(d)
return 36 - nlz32(dist)
}
// newDistCodec creates a new distance codec.
func (dc *distCodec) init() {
for i := range dc.posSlotCodecs {
dc.posSlotCodecs[i] = makeTreeCodec(posSlotBits)
}
for i := range dc.posModel {
posSlot := startPosModel + i
bits := (posSlot >> 1) - 1
dc.posModel[i] = makeTreeReverseCodec(bits)
}
dc.alignCodec = makeTreeReverseCodec(alignBits)
}
// lenState converts the value l to a supported lenState value.
func lenState(l uint32) uint32 {
if l >= lenStates {
l = lenStates - 1
}
return l
}
// Encode encodes the distance using the parameter l. Dist can have values from
// the full range of uint32 values. To get the distance offset the actual match
// distance has to be decreased by 1. A distance offset of 0xffffffff (eos)
// indicates the end of the stream.
func (dc *distCodec) Encode(e *rangeEncoder, dist uint32, l uint32) (err error) {
// Compute the posSlot using nlz32
var posSlot uint32
var bits uint32
if dist < startPosModel {
posSlot = dist
} else {
bits = uint32(30 - nlz32(dist))
posSlot = startPosModel - 2 + (bits << 1)
posSlot += (dist >> uint(bits)) & 1
}
if err = dc.posSlotCodecs[lenState(l)].Encode(e, posSlot); err != nil {
return
}
switch {
case posSlot < startPosModel:
return nil
case posSlot < endPosModel:
tc := &dc.posModel[posSlot-startPosModel]
return tc.Encode(dist, e)
}
dic := directCodec(bits - alignBits)
if err = dic.Encode(e, dist>>alignBits); err != nil {
return
}
return dc.alignCodec.Encode(dist, e)
}
// Decode decodes the distance offset using the parameter l. The dist value
// 0xffffffff (eos) indicates the end of the stream. Add one to the distance
// offset to get the actual match distance.
func (dc *distCodec) Decode(d *rangeDecoder, l uint32) (dist uint32, err error) {
posSlot, err := dc.posSlotCodecs[lenState(l)].Decode(d)
if err != nil {
return
}
// posSlot equals distance
if posSlot < startPosModel {
return posSlot, nil
}
// posSlot uses the individual models
bits := (posSlot >> 1) - 1
dist = (2 | (posSlot & 1)) << bits
var u uint32
if posSlot < endPosModel {
tc := &dc.posModel[posSlot-startPosModel]
if u, err = tc.Decode(d); err != nil {
return 0, err
}
dist += u
return dist, nil
}
// posSlots use direct encoding and a single model for the four align
// bits.
dic := directCodec(bits - alignBits)
if u, err = dic.Decode(d); err != nil {
return 0, err
}
dist += u << alignBits
if u, err = dc.alignCodec.Decode(d); err != nil {
return 0, err
}
dist += u
return dist, nil
}

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// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package lzma
import (
"fmt"
"io"
)
// opLenMargin provides the upper limit of the number of bytes required
// to encode a single operation.
const opLenMargin = 10
// compressFlags control the compression process.
type compressFlags uint32
// Values for compressFlags.
const (
// all data should be compressed, even if compression is not
// optimal.
all compressFlags = 1 << iota
)
// encoderFlags provide the flags for an encoder.
type encoderFlags uint32
// Flags for the encoder.
const (
// eosMarker requests an EOS marker to be written.
eosMarker encoderFlags = 1 << iota
)
// Encoder compresses data buffered in the encoder dictionary and writes
// it into a byte writer.
type encoder struct {
dict *encoderDict
state *state
re *rangeEncoder
start int64
// generate eos marker
marker bool
limit bool
margin int
}
// newEncoder creates a new encoder. If the byte writer must be
// limited use LimitedByteWriter provided by this package. The flags
// argument supports the eosMarker flag, controlling whether a
// terminating end-of-stream marker must be written.
func newEncoder(bw io.ByteWriter, state *state, dict *encoderDict,
flags encoderFlags) (e *encoder, err error) {
re, err := newRangeEncoder(bw)
if err != nil {
return nil, err
}
e = &encoder{
dict: dict,
state: state,
re: re,
marker: flags&eosMarker != 0,
start: dict.Pos(),
margin: opLenMargin,
}
if e.marker {
e.margin += 5
}
return e, nil
}
// Write writes the bytes from p into the dictionary. If not enough
// space is available the data in the dictionary buffer will be
// compressed to make additional space available. If the limit of the
// underlying writer has been reached ErrLimit will be returned.
func (e *encoder) Write(p []byte) (n int, err error) {
for {
k, err := e.dict.Write(p[n:])
n += k
if err == ErrNoSpace {
if err = e.compress(0); err != nil {
return n, err
}
continue
}
return n, err
}
}
// Reopen reopens the encoder with a new byte writer.
func (e *encoder) Reopen(bw io.ByteWriter) error {
var err error
if e.re, err = newRangeEncoder(bw); err != nil {
return err
}
e.start = e.dict.Pos()
e.limit = false
return nil
}
// writeLiteral writes a literal into the LZMA stream
func (e *encoder) writeLiteral(l lit) error {
var err error
state, state2, _ := e.state.states(e.dict.Pos())
if err = e.state.isMatch[state2].Encode(e.re, 0); err != nil {
return err
}
litState := e.state.litState(e.dict.ByteAt(1), e.dict.Pos())
match := e.dict.ByteAt(int(e.state.rep[0]) + 1)
err = e.state.litCodec.Encode(e.re, l.b, state, match, litState)
if err != nil {
return err
}
e.state.updateStateLiteral()
return nil
}
// iverson implements the Iverson operator as proposed by Donald Knuth in his
// book Concrete Mathematics.
func iverson(ok bool) uint32 {
if ok {
return 1
}
return 0
}
// writeMatch writes a repetition operation into the operation stream
func (e *encoder) writeMatch(m match) error {
var err error
if !(minDistance <= m.distance && m.distance <= maxDistance) {
panic(fmt.Errorf("match distance %d out of range", m.distance))
}
dist := uint32(m.distance - minDistance)
if !(minMatchLen <= m.n && m.n <= maxMatchLen) &&
!(dist == e.state.rep[0] && m.n == 1) {
panic(fmt.Errorf(
"match length %d out of range; dist %d rep[0] %d",
m.n, dist, e.state.rep[0]))
}
state, state2, posState := e.state.states(e.dict.Pos())
if err = e.state.isMatch[state2].Encode(e.re, 1); err != nil {
return err
}
g := 0
for ; g < 4; g++ {
if e.state.rep[g] == dist {
break
}
}
b := iverson(g < 4)
if err = e.state.isRep[state].Encode(e.re, b); err != nil {
return err
}
n := uint32(m.n - minMatchLen)
if b == 0 {
// simple match
e.state.rep[3], e.state.rep[2], e.state.rep[1], e.state.rep[0] =
e.state.rep[2], e.state.rep[1], e.state.rep[0], dist
e.state.updateStateMatch()
if err = e.state.lenCodec.Encode(e.re, n, posState); err != nil {
return err
}
return e.state.distCodec.Encode(e.re, dist, n)
}
b = iverson(g != 0)
if err = e.state.isRepG0[state].Encode(e.re, b); err != nil {
return err
}
if b == 0 {
// g == 0
b = iverson(m.n != 1)
if err = e.state.isRepG0Long[state2].Encode(e.re, b); err != nil {
return err
}
if b == 0 {
e.state.updateStateShortRep()
return nil
}
} else {
// g in {1,2,3}
b = iverson(g != 1)
if err = e.state.isRepG1[state].Encode(e.re, b); err != nil {
return err
}
if b == 1 {
// g in {2,3}
b = iverson(g != 2)
err = e.state.isRepG2[state].Encode(e.re, b)
if err != nil {
return err
}
if b == 1 {
e.state.rep[3] = e.state.rep[2]
}
e.state.rep[2] = e.state.rep[1]
}
e.state.rep[1] = e.state.rep[0]
e.state.rep[0] = dist
}
e.state.updateStateRep()
return e.state.repLenCodec.Encode(e.re, n, posState)
}
// writeOp writes a single operation to the range encoder. The function
// checks whether there is enough space available to close the LZMA
// stream.
func (e *encoder) writeOp(op operation) error {
if e.re.Available() < int64(e.margin) {
return ErrLimit
}
switch x := op.(type) {
case lit:
return e.writeLiteral(x)
case match:
return e.writeMatch(x)
default:
panic("unexpected operation")
}
}
// compress compressed data from the dictionary buffer. If the flag all
// is set, all data in the dictionary buffer will be compressed. The
// function returns ErrLimit if the underlying writer has reached its
// limit.
func (e *encoder) compress(flags compressFlags) error {
n := 0
if flags&all == 0 {
n = maxMatchLen - 1
}
d := e.dict
m := d.m
for d.Buffered() > n {
op := m.NextOp(e.state.rep)
if err := e.writeOp(op); err != nil {
return err
}
d.Discard(op.Len())
}
return nil
}
// eosMatch is a pseudo operation that indicates the end of the stream.
var eosMatch = match{distance: maxDistance, n: minMatchLen}
// Close terminates the LZMA stream. If requested the end-of-stream
// marker will be written. If the byte writer limit has been or will be
// reached during compression of the remaining data in the buffer the
// LZMA stream will be closed and data will remain in the buffer.
func (e *encoder) Close() error {
err := e.compress(all)
if err != nil && err != ErrLimit {
return err
}
if e.marker {
if err := e.writeMatch(eosMatch); err != nil {
return err
}
}
err = e.re.Close()
return err
}
// Compressed returns the number bytes of the input data that been
// compressed.
func (e *encoder) Compressed() int64 {
return e.dict.Pos() - e.start
}

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// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package lzma
import (
"errors"
"fmt"
"io"
)
// matcher is an interface that supports the identification of the next
// operation.
type matcher interface {
io.Writer
SetDict(d *encoderDict)
NextOp(rep [4]uint32) operation
}
// encoderDict provides the dictionary of the encoder. It includes an
// addtional buffer atop of the actual dictionary.
type encoderDict struct {
buf buffer
m matcher
head int64
capacity int
// preallocated array
data [maxMatchLen]byte
}
// newEncoderDict creates the encoder dictionary. The argument bufSize
// defines the size of the additional buffer.
func newEncoderDict(dictCap, bufSize int, m matcher) (d *encoderDict, err error) {
if !(1 <= dictCap && int64(dictCap) <= MaxDictCap) {
return nil, errors.New(
"lzma: dictionary capacity out of range")
}
if bufSize < 1 {
return nil, errors.New(
"lzma: buffer size must be larger than zero")
}
d = &encoderDict{
buf: *newBuffer(dictCap + bufSize),
capacity: dictCap,
m: m,
}
m.SetDict(d)
return d, nil
}
// Discard discards n bytes. Note that n must not be larger than
// MaxMatchLen.
func (d *encoderDict) Discard(n int) {
p := d.data[:n]
k, _ := d.buf.Read(p)
if k < n {
panic(fmt.Errorf("lzma: can't discard %d bytes", n))
}
d.head += int64(n)
d.m.Write(p)
}
// Len returns the data available in the encoder dictionary.
func (d *encoderDict) Len() int {
n := d.buf.Available()
if int64(n) > d.head {
return int(d.head)
}
return n
}
// DictLen returns the actual length of data in the dictionary.
func (d *encoderDict) DictLen() int {
if d.head < int64(d.capacity) {
return int(d.head)
}
return d.capacity
}
// Available returns the number of bytes that can be written by a
// following Write call.
func (d *encoderDict) Available() int {
return d.buf.Available() - d.DictLen()
}
// Write writes data into the dictionary buffer. Note that the position
// of the dictionary head will not be moved. If there is not enough
// space in the buffer ErrNoSpace will be returned.
func (d *encoderDict) Write(p []byte) (n int, err error) {
m := d.Available()
if len(p) > m {
p = p[:m]
err = ErrNoSpace
}
var e error
if n, e = d.buf.Write(p); e != nil {
err = e
}
return n, err
}
// Pos returns the position of the head.
func (d *encoderDict) Pos() int64 { return d.head }
// ByteAt returns the byte at the given distance.
func (d *encoderDict) ByteAt(distance int) byte {
if !(0 < distance && distance <= d.Len()) {
return 0
}
i := d.buf.rear - distance
if i < 0 {
i += len(d.buf.data)
}
return d.buf.data[i]
}
// CopyN copies the last n bytes from the dictionary into the provided
// writer. This is used for copying uncompressed data into an
// uncompressed segment.
func (d *encoderDict) CopyN(w io.Writer, n int) (written int, err error) {
if n <= 0 {
return 0, nil
}
m := d.Len()
if n > m {
n = m
err = ErrNoSpace
}
i := d.buf.rear - n
var e error
if i < 0 {
i += len(d.buf.data)
if written, e = w.Write(d.buf.data[i:]); e != nil {
return written, e
}
i = 0
}
var k int
k, e = w.Write(d.buf.data[i:d.buf.rear])
written += k
if e != nil {
err = e
}
return written, err
}
// Buffered returns the number of bytes in the buffer.
func (d *encoderDict) Buffered() int { return d.buf.Buffered() }

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// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package lzma
import (
"errors"
"fmt"
"github.com/ulikunitz/xz/internal/hash"
)
/* For compression we need to find byte sequences that match the byte
* sequence at the dictionary head. A hash table is a simple method to
* provide this capability.
*/
// maxMatches limits the number of matches requested from the Matches
// function. This controls the speed of the overall encoding.
const maxMatches = 16
// shortDists defines the number of short distances supported by the
// implementation.
const shortDists = 8
// The minimum is somehow arbitrary but the maximum is limited by the
// memory requirements of the hash table.
const (
minTableExponent = 9
maxTableExponent = 20
)
// newRoller contains the function used to create an instance of the
// hash.Roller.
var newRoller = func(n int) hash.Roller { return hash.NewCyclicPoly(n) }
// hashTable stores the hash table including the rolling hash method.
//
// We implement chained hashing into a circular buffer. Each entry in
// the circular buffer stores the delta distance to the next position with a
// word that has the same hash value.
type hashTable struct {
dict *encoderDict
// actual hash table
t []int64
// circular list data with the offset to the next word
data []uint32
front int
// mask for computing the index for the hash table
mask uint64
// hash offset; initial value is -int64(wordLen)
hoff int64
// length of the hashed word
wordLen int
// hash roller for computing the hash values for the Write
// method
wr hash.Roller
// hash roller for computing arbitrary hashes
hr hash.Roller
// preallocated slices
p [maxMatches]int64
distances [maxMatches + shortDists]int
}
// hashTableExponent derives the hash table exponent from the dictionary
// capacity.
func hashTableExponent(n uint32) int {
e := 30 - nlz32(n)
switch {
case e < minTableExponent:
e = minTableExponent
case e > maxTableExponent:
e = maxTableExponent
}
return e
}
// newHashTable creates a new hash table for words of length wordLen
func newHashTable(capacity int, wordLen int) (t *hashTable, err error) {
if !(0 < capacity) {
return nil, errors.New(
"newHashTable: capacity must not be negative")
}
exp := hashTableExponent(uint32(capacity))
if !(1 <= wordLen && wordLen <= 4) {
return nil, errors.New("newHashTable: " +
"argument wordLen out of range")
}
n := 1 << uint(exp)
if n <= 0 {
panic("newHashTable: exponent is too large")
}
t = &hashTable{
t: make([]int64, n),
data: make([]uint32, capacity),
mask: (uint64(1) << uint(exp)) - 1,
hoff: -int64(wordLen),
wordLen: wordLen,
wr: newRoller(wordLen),
hr: newRoller(wordLen),
}
return t, nil
}
func (t *hashTable) SetDict(d *encoderDict) { t.dict = d }
// buffered returns the number of bytes that are currently hashed.
func (t *hashTable) buffered() int {
n := t.hoff + 1
switch {
case n <= 0:
return 0
case n >= int64(len(t.data)):
return len(t.data)
}
return int(n)
}
// addIndex adds n to an index ensuring that is stays inside the
// circular buffer for the hash chain.
func (t *hashTable) addIndex(i, n int) int {
i += n - len(t.data)
if i < 0 {
i += len(t.data)
}
return i
}
// putDelta puts the delta instance at the current front of the circular
// chain buffer.
func (t *hashTable) putDelta(delta uint32) {
t.data[t.front] = delta
t.front = t.addIndex(t.front, 1)
}
// putEntry puts a new entry into the hash table. If there is already a
// value stored it is moved into the circular chain buffer.
func (t *hashTable) putEntry(h uint64, pos int64) {
if pos < 0 {
return
}
i := h & t.mask
old := t.t[i] - 1
t.t[i] = pos + 1
var delta int64
if old >= 0 {
delta = pos - old
if delta > 1<<32-1 || delta > int64(t.buffered()) {
delta = 0
}
}
t.putDelta(uint32(delta))
}
// WriteByte converts a single byte into a hash and puts them into the hash
// table.
func (t *hashTable) WriteByte(b byte) error {
h := t.wr.RollByte(b)
t.hoff++
t.putEntry(h, t.hoff)
return nil
}
// Write converts the bytes provided into hash tables and stores the
// abbreviated offsets into the hash table. The method will never return an
// error.
func (t *hashTable) Write(p []byte) (n int, err error) {
for _, b := range p {
// WriteByte doesn't generate an error.
t.WriteByte(b)
}
return len(p), nil
}
// getMatches the matches for a specific hash. The functions returns the
// number of positions found.
//
// TODO: Make a getDistances because that we are actually interested in.
func (t *hashTable) getMatches(h uint64, positions []int64) (n int) {
if t.hoff < 0 || len(positions) == 0 {
return 0
}
buffered := t.buffered()
tailPos := t.hoff + 1 - int64(buffered)
rear := t.front - buffered
if rear >= 0 {
rear -= len(t.data)
}
// get the slot for the hash
pos := t.t[h&t.mask] - 1
delta := pos - tailPos
for {
if delta < 0 {
return n
}
positions[n] = tailPos + delta
n++
if n >= len(positions) {
return n
}
i := rear + int(delta)
if i < 0 {
i += len(t.data)
}
u := t.data[i]
if u == 0 {
return n
}
delta -= int64(u)
}
}
// hash computes the rolling hash for the word stored in p. For correct
// results its length must be equal to t.wordLen.
func (t *hashTable) hash(p []byte) uint64 {
var h uint64
for _, b := range p {
h = t.hr.RollByte(b)
}
return h
}
// Matches fills the positions slice with potential matches. The
// functions returns the number of positions filled into positions. The
// byte slice p must have word length of the hash table.
func (t *hashTable) Matches(p []byte, positions []int64) int {
if len(p) != t.wordLen {
panic(fmt.Errorf(
"byte slice must have length %d", t.wordLen))
}
h := t.hash(p)
return t.getMatches(h, positions)
}
// NextOp identifies the next operation using the hash table.
//
// TODO: Use all repetitions to find matches.
func (t *hashTable) NextOp(rep [4]uint32) operation {
// get positions
data := t.dict.data[:maxMatchLen]
n, _ := t.dict.buf.Peek(data)
data = data[:n]
var p []int64
if n < t.wordLen {
p = t.p[:0]
} else {
p = t.p[:maxMatches]
n = t.Matches(data[:t.wordLen], p)
p = p[:n]
}
// convert positions in potential distances
head := t.dict.head
dists := append(t.distances[:0], 1, 2, 3, 4, 5, 6, 7, 8)
for _, pos := range p {
dis := int(head - pos)
if dis > shortDists {
dists = append(dists, dis)
}
}
// check distances
var m match
dictLen := t.dict.DictLen()
for _, dist := range dists {
if dist > dictLen {
continue
}
// Here comes a trick. We are only interested in matches
// that are longer than the matches we have been found
// before. So before we test the whole byte sequence at
// the given distance, we test the first byte that would
// make the match longer. If it doesn't match the byte
// to match, we don't to care any longer.
i := t.dict.buf.rear - dist + m.n
if i < 0 {
i += len(t.dict.buf.data)
}
if t.dict.buf.data[i] != data[m.n] {
// We can't get a longer match. Jump to the next
// distance.
continue
}
n := t.dict.buf.matchLen(dist, data)
switch n {
case 0:
continue
case 1:
if uint32(dist-minDistance) != rep[0] {
continue
}
}
if n > m.n {
m = match{int64(dist), n}
if n == len(data) {
// No better match will be found.
break
}
}
}
if m.n == 0 {
return lit{data[0]}
}
return m
}

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// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package lzma
import (
"errors"
"fmt"
)
// uint32LE reads an uint32 integer from a byte slice
func uint32LE(b []byte) uint32 {
x := uint32(b[3]) << 24
x |= uint32(b[2]) << 16
x |= uint32(b[1]) << 8
x |= uint32(b[0])
return x
}
// uint64LE converts the uint64 value stored as little endian to an uint64
// value.
func uint64LE(b []byte) uint64 {
x := uint64(b[7]) << 56
x |= uint64(b[6]) << 48
x |= uint64(b[5]) << 40
x |= uint64(b[4]) << 32
x |= uint64(b[3]) << 24
x |= uint64(b[2]) << 16
x |= uint64(b[1]) << 8
x |= uint64(b[0])
return x
}
// putUint32LE puts an uint32 integer into a byte slice that must have at least
// a length of 4 bytes.
func putUint32LE(b []byte, x uint32) {
b[0] = byte(x)
b[1] = byte(x >> 8)
b[2] = byte(x >> 16)
b[3] = byte(x >> 24)
}
// putUint64LE puts the uint64 value into the byte slice as little endian
// value. The byte slice b must have at least place for 8 bytes.
func putUint64LE(b []byte, x uint64) {
b[0] = byte(x)
b[1] = byte(x >> 8)
b[2] = byte(x >> 16)
b[3] = byte(x >> 24)
b[4] = byte(x >> 32)
b[5] = byte(x >> 40)
b[6] = byte(x >> 48)
b[7] = byte(x >> 56)
}
// noHeaderSize defines the value of the length field in the LZMA header.
const noHeaderSize uint64 = 1<<64 - 1
// HeaderLen provides the length of the LZMA file header.
const HeaderLen = 13
// header represents the header of an LZMA file.
type header struct {
properties Properties
dictCap int
// uncompressed size; negative value if no size is given
size int64
}
// marshalBinary marshals the header.
func (h *header) marshalBinary() (data []byte, err error) {
if err = h.properties.verify(); err != nil {
return nil, err
}
if !(0 <= h.dictCap && int64(h.dictCap) <= MaxDictCap) {
return nil, fmt.Errorf("lzma: DictCap %d out of range",
h.dictCap)
}
data = make([]byte, 13)
// property byte
data[0] = h.properties.Code()
// dictionary capacity
putUint32LE(data[1:5], uint32(h.dictCap))
// uncompressed size
var s uint64
if h.size > 0 {
s = uint64(h.size)
} else {
s = noHeaderSize
}
putUint64LE(data[5:], s)
return data, nil
}
// unmarshalBinary unmarshals the header.
func (h *header) unmarshalBinary(data []byte) error {
if len(data) != HeaderLen {
return errors.New("lzma.unmarshalBinary: data has wrong length")
}
// properties
var err error
if h.properties, err = PropertiesForCode(data[0]); err != nil {
return err
}
// dictionary capacity
h.dictCap = int(uint32LE(data[1:]))
if h.dictCap < 0 {
return errors.New(
"LZMA header: dictionary capacity exceeds maximum " +
"integer")
}
// uncompressed size
s := uint64LE(data[5:])
if s == noHeaderSize {
h.size = -1
} else {
h.size = int64(s)
if h.size < 0 {
return errors.New(
"LZMA header: uncompressed size " +
"out of int64 range")
}
}
return nil
}
// validDictCap checks whether the dictionary capacity is correct. This
// is used to weed out wrong file headers.
func validDictCap(dictcap int) bool {
if int64(dictcap) == MaxDictCap {
return true
}
for n := uint(10); n < 32; n++ {
if dictcap == 1<<n {
return true
}
if dictcap == 1<<n+1<<(n-1) {
return true
}
}
return false
}
// ValidHeader checks for a valid LZMA file header. It allows only
// dictionary sizes of 2^n or 2^n+2^(n-1) with n >= 10 or 2^32-1. If
// there is an explicit size it must not exceed 256 GiB. The length of
// the data argument must be HeaderLen.
func ValidHeader(data []byte) bool {
var h header
if err := h.unmarshalBinary(data); err != nil {
return false
}
if !validDictCap(h.dictCap) {
return false
}
return h.size < 0 || h.size <= 1<<38
}

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// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package lzma
import (
"errors"
"fmt"
"io"
)
const (
// maximum size of compressed data in a chunk
maxCompressed = 1 << 16
// maximum size of uncompressed data in a chunk
maxUncompressed = 1 << 21
)
// chunkType represents the type of an LZMA2 chunk. Note that this
// value is an internal representation and no actual encoding of a LZMA2
// chunk header.
type chunkType byte
// Possible values for the chunk type.
const (
// end of stream
cEOS chunkType = iota
// uncompressed; reset dictionary
cUD
// uncompressed; no reset of dictionary
cU
// LZMA compressed; no reset
cL
// LZMA compressed; reset state
cLR
// LZMA compressed; reset state; new property value
cLRN
// LZMA compressed; reset state; new property value; reset dictionary
cLRND
)
// chunkTypeStrings provide a string representation for the chunk types.
var chunkTypeStrings = [...]string{
cEOS: "EOS",
cU: "U",
cUD: "UD",
cL: "L",
cLR: "LR",
cLRN: "LRN",
cLRND: "LRND",
}
// String returns a string representation of the chunk type.
func (c chunkType) String() string {
if !(cEOS <= c && c <= cLRND) {
return "unknown"
}
return chunkTypeStrings[c]
}
// Actual encodings for the chunk types in the value. Note that the high
// uncompressed size bits are stored in the header byte additionally.
const (
hEOS = 0
hUD = 1
hU = 2
hL = 1 << 7
hLR = 1<<7 | 1<<5
hLRN = 1<<7 | 1<<6
hLRND = 1<<7 | 1<<6 | 1<<5
)
// errHeaderByte indicates an unsupported value for the chunk header
// byte. These bytes starts the variable-length chunk header.
var errHeaderByte = errors.New("lzma: unsupported chunk header byte")
// headerChunkType converts the header byte into a chunk type. It
// ignores the uncompressed size bits in the chunk header byte.
func headerChunkType(h byte) (c chunkType, err error) {
if h&hL == 0 {
// no compression
switch h {
case hEOS:
c = cEOS
case hUD:
c = cUD
case hU:
c = cU
default:
return 0, errHeaderByte
}
return
}
switch h & hLRND {
case hL:
c = cL
case hLR:
c = cLR
case hLRN:
c = cLRN
case hLRND:
c = cLRND
default:
return 0, errHeaderByte
}
return
}
// uncompressedHeaderLen provides the length of an uncompressed header
const uncompressedHeaderLen = 3
// headerLen returns the length of the LZMA2 header for a given chunk
// type.
func headerLen(c chunkType) int {
switch c {
case cEOS:
return 1
case cU, cUD:
return uncompressedHeaderLen
case cL, cLR:
return 5
case cLRN, cLRND:
return 6
}
panic(fmt.Errorf("unsupported chunk type %d", c))
}
// chunkHeader represents the contents of a chunk header.
type chunkHeader struct {
ctype chunkType
uncompressed uint32
compressed uint16
props Properties
}
// String returns a string representation of the chunk header.
func (h *chunkHeader) String() string {
return fmt.Sprintf("%s %d %d %s", h.ctype, h.uncompressed,
h.compressed, &h.props)
}
// UnmarshalBinary reads the content of the chunk header from the data
// slice. The slice must have the correct length.
func (h *chunkHeader) UnmarshalBinary(data []byte) error {
if len(data) == 0 {
return errors.New("no data")
}
c, err := headerChunkType(data[0])
if err != nil {
return err
}
n := headerLen(c)
if len(data) < n {
return errors.New("incomplete data")
}
if len(data) > n {
return errors.New("invalid data length")
}
*h = chunkHeader{ctype: c}
if c == cEOS {
return nil
}
h.uncompressed = uint32(uint16BE(data[1:3]))
if c <= cU {
return nil
}
h.uncompressed |= uint32(data[0]&^hLRND) << 16
h.compressed = uint16BE(data[3:5])
if c <= cLR {
return nil
}
h.props, err = PropertiesForCode(data[5])
return err
}
// MarshalBinary encodes the chunk header value. The function checks
// whether the content of the chunk header is correct.
func (h *chunkHeader) MarshalBinary() (data []byte, err error) {
if h.ctype > cLRND {
return nil, errors.New("invalid chunk type")
}
if err = h.props.verify(); err != nil {
return nil, err
}
data = make([]byte, headerLen(h.ctype))
switch h.ctype {
case cEOS:
return data, nil
case cUD:
data[0] = hUD
case cU:
data[0] = hU
case cL:
data[0] = hL
case cLR:
data[0] = hLR
case cLRN:
data[0] = hLRN
case cLRND:
data[0] = hLRND
}
putUint16BE(data[1:3], uint16(h.uncompressed))
if h.ctype <= cU {
return data, nil
}
data[0] |= byte(h.uncompressed>>16) &^ hLRND
putUint16BE(data[3:5], h.compressed)
if h.ctype <= cLR {
return data, nil
}
data[5] = h.props.Code()
return data, nil
}
// readChunkHeader reads the chunk header from the IO reader.
func readChunkHeader(r io.Reader) (h *chunkHeader, err error) {
p := make([]byte, 1, 6)
if _, err = io.ReadFull(r, p); err != nil {
return
}
c, err := headerChunkType(p[0])
if err != nil {
return
}
p = p[:headerLen(c)]
if _, err = io.ReadFull(r, p[1:]); err != nil {
return
}
h = new(chunkHeader)
if err = h.UnmarshalBinary(p); err != nil {
return nil, err
}
return h, nil
}
// uint16BE converts a big-endian uint16 representation to an uint16
// value.
func uint16BE(p []byte) uint16 {
return uint16(p[0])<<8 | uint16(p[1])
}
// putUint16BE puts the big-endian uint16 presentation into the given
// slice.
func putUint16BE(p []byte, x uint16) {
p[0] = byte(x >> 8)
p[1] = byte(x)
}
// chunkState is used to manage the state of the chunks
type chunkState byte
// start and stop define the initial and terminating state of the chunk
// state
const (
start chunkState = 'S'
stop = 'T'
)
// errors for the chunk state handling
var (
errChunkType = errors.New("lzma: unexpected chunk type")
errState = errors.New("lzma: wrong chunk state")
)
// next transitions state based on chunk type input
func (c *chunkState) next(ctype chunkType) error {
switch *c {
// start state
case 'S':
switch ctype {
case cEOS:
*c = 'T'
case cUD:
*c = 'R'
case cLRND:
*c = 'L'
default:
return errChunkType
}
// normal LZMA mode
case 'L':
switch ctype {
case cEOS:
*c = 'T'
case cUD:
*c = 'R'
case cU:
*c = 'U'
case cL, cLR, cLRN, cLRND:
break
default:
return errChunkType
}
// reset required
case 'R':
switch ctype {
case cEOS:
*c = 'T'
case cUD, cU:
break
case cLRN, cLRND:
*c = 'L'
default:
return errChunkType
}
// uncompressed
case 'U':
switch ctype {
case cEOS:
*c = 'T'
case cUD:
*c = 'R'
case cU:
break
case cL, cLR, cLRN, cLRND:
*c = 'L'
default:
return errChunkType
}
// terminal state
case 'T':
return errChunkType
default:
return errState
}
return nil
}
// defaultChunkType returns the default chunk type for each chunk state.
func (c chunkState) defaultChunkType() chunkType {
switch c {
case 'S':
return cLRND
case 'L', 'U':
return cL
case 'R':
return cLRN
default:
// no error
return cEOS
}
}
// maxDictCap defines the maximum dictionary capacity supported by the
// LZMA2 dictionary capacity encoding.
const maxDictCap = 1<<32 - 1
// maxDictCapCode defines the maximum dictionary capacity code.
const maxDictCapCode = 40
// The function decodes the dictionary capacity byte, but doesn't change
// for the correct range of the given byte.
func decodeDictCap(c byte) int64 {
return (2 | int64(c)&1) << (11 + (c>>1)&0x1f)
}
// DecodeDictCap decodes the encoded dictionary capacity. The function
// returns an error if the code is out of range.
func DecodeDictCap(c byte) (n int64, err error) {
if c >= maxDictCapCode {
if c == maxDictCapCode {
return maxDictCap, nil
}
return 0, errors.New("lzma: invalid dictionary size code")
}
return decodeDictCap(c), nil
}
// EncodeDictCap encodes a dictionary capacity. The function returns the
// code for the capacity that is greater or equal n. If n exceeds the
// maximum support dictionary capacity, the maximum value is returned.
func EncodeDictCap(n int64) byte {
a, b := byte(0), byte(40)
for a < b {
c := a + (b-a)>>1
m := decodeDictCap(c)
if n <= m {
if n == m {
return c
}
b = c
} else {
a = c + 1
}
}
return a
}

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// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package lzma
import "errors"
// maxPosBits defines the number of bits of the position value that are used to
// to compute the posState value. The value is used to select the tree codec
// for length encoding and decoding.
const maxPosBits = 4
// minMatchLen and maxMatchLen give the minimum and maximum values for
// encoding and decoding length values. minMatchLen is also used as base
// for the encoded length values.
const (
minMatchLen = 2
maxMatchLen = minMatchLen + 16 + 256 - 1
)
// lengthCodec support the encoding of the length value.
type lengthCodec struct {
choice [2]prob
low [1 << maxPosBits]treeCodec
mid [1 << maxPosBits]treeCodec
high treeCodec
}
// deepcopy initializes the lc value as deep copy of the source value.
func (lc *lengthCodec) deepcopy(src *lengthCodec) {
if lc == src {
return
}
lc.choice = src.choice
for i := range lc.low {
lc.low[i].deepcopy(&src.low[i])
}
for i := range lc.mid {
lc.mid[i].deepcopy(&src.mid[i])
}
lc.high.deepcopy(&src.high)
}
// init initializes a new length codec.
func (lc *lengthCodec) init() {
for i := range lc.choice {
lc.choice[i] = probInit
}
for i := range lc.low {
lc.low[i] = makeTreeCodec(3)
}
for i := range lc.mid {
lc.mid[i] = makeTreeCodec(3)
}
lc.high = makeTreeCodec(8)
}
// lBits gives the number of bits used for the encoding of the l value
// provided to the range encoder.
func lBits(l uint32) int {
switch {
case l < 8:
return 4
case l < 16:
return 5
default:
return 10
}
}
// Encode encodes the length offset. The length offset l can be compute by
// subtracting minMatchLen (2) from the actual length.
//
// l = length - minMatchLen
//
func (lc *lengthCodec) Encode(e *rangeEncoder, l uint32, posState uint32,
) (err error) {
if l > maxMatchLen-minMatchLen {
return errors.New("lengthCodec.Encode: l out of range")
}
if l < 8 {
if err = lc.choice[0].Encode(e, 0); err != nil {
return
}
return lc.low[posState].Encode(e, l)
}
if err = lc.choice[0].Encode(e, 1); err != nil {
return
}
if l < 16 {
if err = lc.choice[1].Encode(e, 0); err != nil {
return
}
return lc.mid[posState].Encode(e, l-8)
}
if err = lc.choice[1].Encode(e, 1); err != nil {
return
}
if err = lc.high.Encode(e, l-16); err != nil {
return
}
return nil
}
// Decode reads the length offset. Add minMatchLen to compute the actual length
// to the length offset l.
func (lc *lengthCodec) Decode(d *rangeDecoder, posState uint32,
) (l uint32, err error) {
var b uint32
if b, err = lc.choice[0].Decode(d); err != nil {
return
}
if b == 0 {
l, err = lc.low[posState].Decode(d)
return
}
if b, err = lc.choice[1].Decode(d); err != nil {
return
}
if b == 0 {
l, err = lc.mid[posState].Decode(d)
l += 8
return
}
l, err = lc.high.Decode(d)
l += 16
return
}

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// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package lzma
// literalCodec supports the encoding of literal. It provides 768 probability
// values per literal state. The upper 512 probabilities are used with the
// context of a match bit.
type literalCodec struct {
probs []prob
}
// deepcopy initializes literal codec c as a deep copy of the source.
func (c *literalCodec) deepcopy(src *literalCodec) {
if c == src {
return
}
c.probs = make([]prob, len(src.probs))
copy(c.probs, src.probs)
}
// init initializes the literal codec.
func (c *literalCodec) init(lc, lp int) {
switch {
case !(minLC <= lc && lc <= maxLC):
panic("lc out of range")
case !(minLP <= lp && lp <= maxLP):
panic("lp out of range")
}
c.probs = make([]prob, 0x300<<uint(lc+lp))
for i := range c.probs {
c.probs[i] = probInit
}
}
// Encode encodes the byte s using a range encoder as well as the current LZMA
// encoder state, a match byte and the literal state.
func (c *literalCodec) Encode(e *rangeEncoder, s byte,
state uint32, match byte, litState uint32,
) (err error) {
k := litState * 0x300
probs := c.probs[k : k+0x300]
symbol := uint32(1)
r := uint32(s)
if state >= 7 {
m := uint32(match)
for {
matchBit := (m >> 7) & 1
m <<= 1
bit := (r >> 7) & 1
r <<= 1
i := ((1 + matchBit) << 8) | symbol
if err = probs[i].Encode(e, bit); err != nil {
return
}
symbol = (symbol << 1) | bit
if matchBit != bit {
break
}
if symbol >= 0x100 {
break
}
}
}
for symbol < 0x100 {
bit := (r >> 7) & 1
r <<= 1
if err = probs[symbol].Encode(e, bit); err != nil {
return
}
symbol = (symbol << 1) | bit
}
return nil
}
// Decode decodes a literal byte using the range decoder as well as the LZMA
// state, a match byte, and the literal state.
func (c *literalCodec) Decode(d *rangeDecoder,
state uint32, match byte, litState uint32,
) (s byte, err error) {
k := litState * 0x300
probs := c.probs[k : k+0x300]
symbol := uint32(1)
if state >= 7 {
m := uint32(match)
for {
matchBit := (m >> 7) & 1
m <<= 1
i := ((1 + matchBit) << 8) | symbol
bit, err := d.DecodeBit(&probs[i])
if err != nil {
return 0, err
}
symbol = (symbol << 1) | bit
if matchBit != bit {
break
}
if symbol >= 0x100 {
break
}
}
}
for symbol < 0x100 {
bit, err := d.DecodeBit(&probs[symbol])
if err != nil {
return 0, err
}
symbol = (symbol << 1) | bit
}
s = byte(symbol - 0x100)
return s, nil
}
// minLC and maxLC define the range for LC values.
const (
minLC = 0
maxLC = 8
)
// minLC and maxLC define the range for LP values.
const (
minLP = 0
maxLP = 4
)
// minState and maxState define a range for the state values stored in
// the State values.
const (
minState = 0
maxState = 11
)

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// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package lzma
import "errors"
// MatchAlgorithm identifies an algorithm to find matches in the
// dictionary.
type MatchAlgorithm byte
// Supported matcher algorithms.
const (
HashTable4 MatchAlgorithm = iota
BinaryTree
)
// maStrings are used by the String method.
var maStrings = map[MatchAlgorithm]string{
HashTable4: "HashTable4",
BinaryTree: "BinaryTree",
}
// String returns a string representation of the Matcher.
func (a MatchAlgorithm) String() string {
if s, ok := maStrings[a]; ok {
return s
}
return "unknown"
}
var errUnsupportedMatchAlgorithm = errors.New(
"lzma: unsupported match algorithm value")
// verify checks whether the matcher value is supported.
func (a MatchAlgorithm) verify() error {
if _, ok := maStrings[a]; !ok {
return errUnsupportedMatchAlgorithm
}
return nil
}
func (a MatchAlgorithm) new(dictCap int) (m matcher, err error) {
switch a {
case HashTable4:
return newHashTable(dictCap, 4)
case BinaryTree:
return newBinTree(dictCap)
}
return nil, errUnsupportedMatchAlgorithm
}

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// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package lzma
import (
"errors"
"fmt"
"unicode"
)
// operation represents an operation on the dictionary during encoding or
// decoding.
type operation interface {
Len() int
}
// rep represents a repetition at the given distance and the given length
type match struct {
// supports all possible distance values, including the eos marker
distance int64
// length
n int
}
// verify checks whether the match is valid. If that is not the case an
// error is returned.
func (m match) verify() error {
if !(minDistance <= m.distance && m.distance <= maxDistance) {
return errors.New("distance out of range")
}
if !(1 <= m.n && m.n <= maxMatchLen) {
return errors.New("length out of range")
}
return nil
}
// l return the l-value for the match, which is the difference of length
// n and 2.
func (m match) l() uint32 {
return uint32(m.n - minMatchLen)
}
// dist returns the dist value for the match, which is one less of the
// distance stored in the match.
func (m match) dist() uint32 {
return uint32(m.distance - minDistance)
}
// Len returns the number of bytes matched.
func (m match) Len() int {
return m.n
}
// String returns a string representation for the repetition.
func (m match) String() string {
return fmt.Sprintf("M{%d,%d}", m.distance, m.n)
}
// lit represents a single byte literal.
type lit struct {
b byte
}
// Len returns 1 for the single byte literal.
func (l lit) Len() int {
return 1
}
// String returns a string representation for the literal.
func (l lit) String() string {
var c byte
if unicode.IsPrint(rune(l.b)) {
c = l.b
} else {
c = '.'
}
return fmt.Sprintf("L{%c/%02x}", c, l.b)
}

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// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package lzma
// movebits defines the number of bits used for the updates of probability
// values.
const movebits = 5
// probbits defines the number of bits of a probability value.
const probbits = 11
// probInit defines 0.5 as initial value for prob values.
const probInit prob = 1 << (probbits - 1)
// Type prob represents probabilities. The type can also be used to encode and
// decode single bits.
type prob uint16
// Dec decreases the probability. The decrease is proportional to the
// probability value.
func (p *prob) dec() {
*p -= *p >> movebits
}
// Inc increases the probability. The Increase is proportional to the
// difference of 1 and the probability value.
func (p *prob) inc() {
*p += ((1 << probbits) - *p) >> movebits
}
// Computes the new bound for a given range using the probability value.
func (p prob) bound(r uint32) uint32 {
return (r >> probbits) * uint32(p)
}
// Bits returns 1. One is the number of bits that can be encoded or decoded
// with a single prob value.
func (p prob) Bits() int {
return 1
}
// Encode encodes the least-significant bit of v. Note that the p value will be
// changed.
func (p *prob) Encode(e *rangeEncoder, v uint32) error {
return e.EncodeBit(v, p)
}
// Decode decodes a single bit. Note that the p value will change.
func (p *prob) Decode(d *rangeDecoder) (v uint32, err error) {
return d.DecodeBit(p)
}

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// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package lzma
import (
"errors"
"fmt"
)
// maximum and minimum values for the LZMA properties.
const (
minPB = 0
maxPB = 4
)
// maxPropertyCode is the possible maximum of a properties code byte.
const maxPropertyCode = (maxPB+1)*(maxLP+1)*(maxLC+1) - 1
// Properties contains the parameters LC, LP and PB. The parameter LC
// defines the number of literal context bits; parameter LP the number
// of literal position bits and PB the number of position bits.
type Properties struct {
LC int
LP int
PB int
}
// String returns the properties in a string representation.
func (p *Properties) String() string {
return fmt.Sprintf("LC %d LP %d PB %d", p.LC, p.LP, p.PB)
}
// PropertiesForCode converts a properties code byte into a Properties value.
func PropertiesForCode(code byte) (p Properties, err error) {
if code > maxPropertyCode {
return p, errors.New("lzma: invalid properties code")
}
p.LC = int(code % 9)
code /= 9
p.LP = int(code % 5)
code /= 5
p.PB = int(code % 5)
return p, err
}
// verify checks the properties for correctness.
func (p *Properties) verify() error {
if p == nil {
return errors.New("lzma: properties are nil")
}
if !(minLC <= p.LC && p.LC <= maxLC) {
return errors.New("lzma: lc out of range")
}
if !(minLP <= p.LP && p.LP <= maxLP) {
return errors.New("lzma: lp out of range")
}
if !(minPB <= p.PB && p.PB <= maxPB) {
return errors.New("lzma: pb out of range")
}
return nil
}
// Code converts the properties to a byte. The function assumes that
// the properties components are all in range.
func (p Properties) Code() byte {
return byte((p.PB*5+p.LP)*9 + p.LC)
}

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// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package lzma
import (
"errors"
"io"
)
// rangeEncoder implements range encoding of single bits. The low value can
// overflow therefore we need uint64. The cache value is used to handle
// overflows.
type rangeEncoder struct {
lbw *LimitedByteWriter
nrange uint32
low uint64
cacheLen int64
cache byte
}
// maxInt64 provides the maximal value of the int64 type
const maxInt64 = 1<<63 - 1
// newRangeEncoder creates a new range encoder.
func newRangeEncoder(bw io.ByteWriter) (re *rangeEncoder, err error) {
lbw, ok := bw.(*LimitedByteWriter)
if !ok {
lbw = &LimitedByteWriter{BW: bw, N: maxInt64}
}
return &rangeEncoder{
lbw: lbw,
nrange: 0xffffffff,
cacheLen: 1}, nil
}
// Available returns the number of bytes that still can be written. The
// method takes the bytes that will be currently written by Close into
// account.
func (e *rangeEncoder) Available() int64 {
return e.lbw.N - (e.cacheLen + 4)
}
// writeByte writes a single byte to the underlying writer. An error is
// returned if the limit is reached. The written byte will be counted if
// the underlying writer doesn't return an error.
func (e *rangeEncoder) writeByte(c byte) error {
if e.Available() < 1 {
return ErrLimit
}
return e.lbw.WriteByte(c)
}
// DirectEncodeBit encodes the least-significant bit of b with probability 1/2.
func (e *rangeEncoder) DirectEncodeBit(b uint32) error {
e.nrange >>= 1
e.low += uint64(e.nrange) & (0 - (uint64(b) & 1))
// normalize
const top = 1 << 24
if e.nrange >= top {
return nil
}
e.nrange <<= 8
return e.shiftLow()
}
// EncodeBit encodes the least significant bit of b. The p value will be
// updated by the function depending on the bit encoded.
func (e *rangeEncoder) EncodeBit(b uint32, p *prob) error {
bound := p.bound(e.nrange)
if b&1 == 0 {
e.nrange = bound
p.inc()
} else {
e.low += uint64(bound)
e.nrange -= bound
p.dec()
}
// normalize
const top = 1 << 24
if e.nrange >= top {
return nil
}
e.nrange <<= 8
return e.shiftLow()
}
// Close writes a complete copy of the low value.
func (e *rangeEncoder) Close() error {
for i := 0; i < 5; i++ {
if err := e.shiftLow(); err != nil {
return err
}
}
return nil
}
// shiftLow shifts the low value for 8 bit. The shifted byte is written into
// the byte writer. The cache value is used to handle overflows.
func (e *rangeEncoder) shiftLow() error {
if uint32(e.low) < 0xff000000 || (e.low>>32) != 0 {
tmp := e.cache
for {
err := e.writeByte(tmp + byte(e.low>>32))
if err != nil {
return err
}
tmp = 0xff
e.cacheLen--
if e.cacheLen <= 0 {
if e.cacheLen < 0 {
panic("negative cacheLen")
}
break
}
}
e.cache = byte(uint32(e.low) >> 24)
}
e.cacheLen++
e.low = uint64(uint32(e.low) << 8)
return nil
}
// rangeDecoder decodes single bits of the range encoding stream.
type rangeDecoder struct {
br io.ByteReader
nrange uint32
code uint32
}
// init initializes the range decoder, by reading from the byte reader.
func (d *rangeDecoder) init() error {
d.nrange = 0xffffffff
d.code = 0
b, err := d.br.ReadByte()
if err != nil {
return err
}
if b != 0 {
return errors.New("newRangeDecoder: first byte not zero")
}
for i := 0; i < 4; i++ {
if err = d.updateCode(); err != nil {
return err
}
}
if d.code >= d.nrange {
return errors.New("newRangeDecoder: d.code >= d.nrange")
}
return nil
}
// newRangeDecoder initializes a range decoder. It reads five bytes from the
// reader and therefore may return an error.
func newRangeDecoder(br io.ByteReader) (d *rangeDecoder, err error) {
d = &rangeDecoder{br: br, nrange: 0xffffffff}
b, err := d.br.ReadByte()
if err != nil {
return nil, err
}
if b != 0 {
return nil, errors.New("newRangeDecoder: first byte not zero")
}
for i := 0; i < 4; i++ {
if err = d.updateCode(); err != nil {
return nil, err
}
}
if d.code >= d.nrange {
return nil, errors.New("newRangeDecoder: d.code >= d.nrange")
}
return d, nil
}
// possiblyAtEnd checks whether the decoder may be at the end of the stream.
func (d *rangeDecoder) possiblyAtEnd() bool {
return d.code == 0
}
// DirectDecodeBit decodes a bit with probability 1/2. The return value b will
// contain the bit at the least-significant position. All other bits will be
// zero.
func (d *rangeDecoder) DirectDecodeBit() (b uint32, err error) {
d.nrange >>= 1
d.code -= d.nrange
t := 0 - (d.code >> 31)
d.code += d.nrange & t
b = (t + 1) & 1
// d.code will stay less then d.nrange
// normalize
// assume d.code < d.nrange
const top = 1 << 24
if d.nrange >= top {
return b, nil
}
d.nrange <<= 8
// d.code < d.nrange will be maintained
return b, d.updateCode()
}
// decodeBit decodes a single bit. The bit will be returned at the
// least-significant position. All other bits will be zero. The probability
// value will be updated.
func (d *rangeDecoder) DecodeBit(p *prob) (b uint32, err error) {
bound := p.bound(d.nrange)
if d.code < bound {
d.nrange = bound
p.inc()
b = 0
} else {
d.code -= bound
d.nrange -= bound
p.dec()
b = 1
}
// normalize
// assume d.code < d.nrange
const top = 1 << 24
if d.nrange >= top {
return b, nil
}
d.nrange <<= 8
// d.code < d.nrange will be maintained
return b, d.updateCode()
}
// updateCode reads a new byte into the code.
func (d *rangeDecoder) updateCode() error {
b, err := d.br.ReadByte()
if err != nil {
return err
}
d.code = (d.code << 8) | uint32(b)
return nil
}

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// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Package lzma supports the decoding and encoding of LZMA streams.
// Reader and Writer support the classic LZMA format. Reader2 and
// Writer2 support the decoding and encoding of LZMA2 streams.
//
// The package is written completely in Go and doesn't rely on any external
// library.
package lzma
import (
"errors"
"io"
)
// ReaderConfig stores the parameters for the reader of the classic LZMA
// format.
type ReaderConfig struct {
DictCap int
}
// fill converts the zero values of the configuration to the default values.
func (c *ReaderConfig) fill() {
if c.DictCap == 0 {
c.DictCap = 8 * 1024 * 1024
}
}
// Verify checks the reader configuration for errors. Zero values will
// be replaced by default values.
func (c *ReaderConfig) Verify() error {
c.fill()
if !(MinDictCap <= c.DictCap && int64(c.DictCap) <= MaxDictCap) {
return errors.New("lzma: dictionary capacity is out of range")
}
return nil
}
// Reader provides a reader for LZMA files or streams.
type Reader struct {
lzma io.Reader
h header
d *decoder
}
// NewReader creates a new reader for an LZMA stream using the classic
// format. NewReader reads and checks the header of the LZMA stream.
func NewReader(lzma io.Reader) (r *Reader, err error) {
return ReaderConfig{}.NewReader(lzma)
}
// NewReader creates a new reader for an LZMA stream in the classic
// format. The function reads and verifies the the header of the LZMA
// stream.
func (c ReaderConfig) NewReader(lzma io.Reader) (r *Reader, err error) {
if err = c.Verify(); err != nil {
return nil, err
}
data := make([]byte, HeaderLen)
if _, err := io.ReadFull(lzma, data); err != nil {
if err == io.EOF {
return nil, errors.New("lzma: unexpected EOF")
}
return nil, err
}
r = &Reader{lzma: lzma}
if err = r.h.unmarshalBinary(data); err != nil {
return nil, err
}
if r.h.dictCap < MinDictCap {
return nil, errors.New("lzma: dictionary capacity too small")
}
dictCap := r.h.dictCap
if c.DictCap > dictCap {
dictCap = c.DictCap
}
state := newState(r.h.properties)
dict, err := newDecoderDict(dictCap)
if err != nil {
return nil, err
}
r.d, err = newDecoder(ByteReader(lzma), state, dict, r.h.size)
if err != nil {
return nil, err
}
return r, nil
}
// EOSMarker indicates that an EOS marker has been encountered.
func (r *Reader) EOSMarker() bool {
return r.d.eosMarker
}
// Read returns uncompressed data.
func (r *Reader) Read(p []byte) (n int, err error) {
return r.d.Read(p)
}

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// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package lzma
import (
"errors"
"io"
"github.com/ulikunitz/xz/internal/xlog"
)
// Reader2Config stores the parameters for the LZMA2 reader.
// format.
type Reader2Config struct {
DictCap int
}
// fill converts the zero values of the configuration to the default values.
func (c *Reader2Config) fill() {
if c.DictCap == 0 {
c.DictCap = 8 * 1024 * 1024
}
}
// Verify checks the reader configuration for errors. Zero configuration values
// will be replaced by default values.
func (c *Reader2Config) Verify() error {
c.fill()
if !(MinDictCap <= c.DictCap && int64(c.DictCap) <= MaxDictCap) {
return errors.New("lzma: dictionary capacity is out of range")
}
return nil
}
// Reader2 supports the reading of LZMA2 chunk sequences. Note that the
// first chunk should have a dictionary reset and the first compressed
// chunk a properties reset. The chunk sequence may not be terminated by
// an end-of-stream chunk.
type Reader2 struct {
r io.Reader
err error
dict *decoderDict
ur *uncompressedReader
decoder *decoder
chunkReader io.Reader
cstate chunkState
ctype chunkType
}
// NewReader2 creates a reader for an LZMA2 chunk sequence.
func NewReader2(lzma2 io.Reader) (r *Reader2, err error) {
return Reader2Config{}.NewReader2(lzma2)
}
// NewReader2 creates an LZMA2 reader using the given configuration.
func (c Reader2Config) NewReader2(lzma2 io.Reader) (r *Reader2, err error) {
if err = c.Verify(); err != nil {
return nil, err
}
r = &Reader2{r: lzma2, cstate: start}
r.dict, err = newDecoderDict(c.DictCap)
if err != nil {
return nil, err
}
if err = r.startChunk(); err != nil {
r.err = err
}
return r, nil
}
// uncompressed tests whether the chunk type specifies an uncompressed
// chunk.
func uncompressed(ctype chunkType) bool {
return ctype == cU || ctype == cUD
}
// startChunk parses a new chunk.
func (r *Reader2) startChunk() error {
r.chunkReader = nil
header, err := readChunkHeader(r.r)
if err != nil {
if err == io.EOF {
err = io.ErrUnexpectedEOF
}
return err
}
xlog.Debugf("chunk header %v", header)
if err = r.cstate.next(header.ctype); err != nil {
return err
}
if r.cstate == stop {
return io.EOF
}
if header.ctype == cUD || header.ctype == cLRND {
r.dict.Reset()
}
size := int64(header.uncompressed) + 1
if uncompressed(header.ctype) {
if r.ur != nil {
r.ur.Reopen(r.r, size)
} else {
r.ur = newUncompressedReader(r.r, r.dict, size)
}
r.chunkReader = r.ur
return nil
}
br := ByteReader(io.LimitReader(r.r, int64(header.compressed)+1))
if r.decoder == nil {
state := newState(header.props)
r.decoder, err = newDecoder(br, state, r.dict, size)
if err != nil {
return err
}
r.chunkReader = r.decoder
return nil
}
switch header.ctype {
case cLR:
r.decoder.State.Reset()
case cLRN, cLRND:
r.decoder.State = newState(header.props)
}
err = r.decoder.Reopen(br, size)
if err != nil {
return err
}
r.chunkReader = r.decoder
return nil
}
// Read reads data from the LZMA2 chunk sequence.
func (r *Reader2) Read(p []byte) (n int, err error) {
if r.err != nil {
return 0, r.err
}
for n < len(p) {
var k int
k, err = r.chunkReader.Read(p[n:])
n += k
if err != nil {
if err == io.EOF {
err = r.startChunk()
if err == nil {
continue
}
}
r.err = err
return n, err
}
if k == 0 {
r.err = errors.New("lzma: Reader2 doesn't get data")
return n, r.err
}
}
return n, nil
}
// EOS returns whether the LZMA2 stream has been terminated by an
// end-of-stream chunk.
func (r *Reader2) EOS() bool {
return r.cstate == stop
}
// uncompressedReader is used to read uncompressed chunks.
type uncompressedReader struct {
lr io.LimitedReader
Dict *decoderDict
eof bool
err error
}
// newUncompressedReader initializes a new uncompressedReader.
func newUncompressedReader(r io.Reader, dict *decoderDict, size int64) *uncompressedReader {
ur := &uncompressedReader{
lr: io.LimitedReader{R: r, N: size},
Dict: dict,
}
return ur
}
// Reopen reinitializes an uncompressed reader.
func (ur *uncompressedReader) Reopen(r io.Reader, size int64) {
ur.err = nil
ur.eof = false
ur.lr = io.LimitedReader{R: r, N: size}
}
// fill reads uncompressed data into the dictionary.
func (ur *uncompressedReader) fill() error {
if !ur.eof {
n, err := io.CopyN(ur.Dict, &ur.lr, int64(ur.Dict.Available()))
if err != io.EOF {
return err
}
ur.eof = true
if n > 0 {
return nil
}
}
if ur.lr.N != 0 {
return io.ErrUnexpectedEOF
}
return io.EOF
}
// Read reads uncompressed data from the limited reader.
func (ur *uncompressedReader) Read(p []byte) (n int, err error) {
if ur.err != nil {
return 0, ur.err
}
for {
var k int
k, err = ur.Dict.Read(p[n:])
n += k
if n >= len(p) {
return n, nil
}
if err != nil {
break
}
err = ur.fill()
if err != nil {
break
}
}
ur.err = err
return n, err
}

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// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package lzma
// states defines the overall state count
const states = 12
// State maintains the full state of the operation encoding or decoding
// process.
type state struct {
rep [4]uint32
isMatch [states << maxPosBits]prob
isRepG0Long [states << maxPosBits]prob
isRep [states]prob
isRepG0 [states]prob
isRepG1 [states]prob
isRepG2 [states]prob
litCodec literalCodec
lenCodec lengthCodec
repLenCodec lengthCodec
distCodec distCodec
state uint32
posBitMask uint32
Properties Properties
}
// initProbSlice initializes a slice of probabilities.
func initProbSlice(p []prob) {
for i := range p {
p[i] = probInit
}
}
// Reset sets all state information to the original values.
func (s *state) Reset() {
p := s.Properties
*s = state{
Properties: p,
// dict: s.dict,
posBitMask: (uint32(1) << uint(p.PB)) - 1,
}
initProbSlice(s.isMatch[:])
initProbSlice(s.isRep[:])
initProbSlice(s.isRepG0[:])
initProbSlice(s.isRepG1[:])
initProbSlice(s.isRepG2[:])
initProbSlice(s.isRepG0Long[:])
s.litCodec.init(p.LC, p.LP)
s.lenCodec.init()
s.repLenCodec.init()
s.distCodec.init()
}
// initState initializes the state.
func initState(s *state, p Properties) {
*s = state{Properties: p}
s.Reset()
}
// newState creates a new state from the give Properties.
func newState(p Properties) *state {
s := &state{Properties: p}
s.Reset()
return s
}
// deepcopy initializes s as a deep copy of the source.
func (s *state) deepcopy(src *state) {
if s == src {
return
}
s.rep = src.rep
s.isMatch = src.isMatch
s.isRepG0Long = src.isRepG0Long
s.isRep = src.isRep
s.isRepG0 = src.isRepG0
s.isRepG1 = src.isRepG1
s.isRepG2 = src.isRepG2
s.litCodec.deepcopy(&src.litCodec)
s.lenCodec.deepcopy(&src.lenCodec)
s.repLenCodec.deepcopy(&src.repLenCodec)
s.distCodec.deepcopy(&src.distCodec)
s.state = src.state
s.posBitMask = src.posBitMask
s.Properties = src.Properties
}
// cloneState creates a new clone of the give state.
func cloneState(src *state) *state {
s := new(state)
s.deepcopy(src)
return s
}
// updateStateLiteral updates the state for a literal.
func (s *state) updateStateLiteral() {
switch {
case s.state < 4:
s.state = 0
return
case s.state < 10:
s.state -= 3
return
}
s.state -= 6
}
// updateStateMatch updates the state for a match.
func (s *state) updateStateMatch() {
if s.state < 7 {
s.state = 7
} else {
s.state = 10
}
}
// updateStateRep updates the state for a repetition.
func (s *state) updateStateRep() {
if s.state < 7 {
s.state = 8
} else {
s.state = 11
}
}
// updateStateShortRep updates the state for a short repetition.
func (s *state) updateStateShortRep() {
if s.state < 7 {
s.state = 9
} else {
s.state = 11
}
}
// states computes the states of the operation codec.
func (s *state) states(dictHead int64) (state1, state2, posState uint32) {
state1 = s.state
posState = uint32(dictHead) & s.posBitMask
state2 = (s.state << maxPosBits) | posState
return
}
// litState computes the literal state.
func (s *state) litState(prev byte, dictHead int64) uint32 {
lp, lc := uint(s.Properties.LP), uint(s.Properties.LC)
litState := ((uint32(dictHead) & ((1 << lp) - 1)) << lc) |
(uint32(prev) >> (8 - lc))
return litState
}

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// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package lzma
// treeCodec encodes or decodes values with a fixed bit size. It is using a
// tree of probability value. The root of the tree is the most-significant bit.
type treeCodec struct {
probTree
}
// makeTreeCodec makes a tree codec. The bits value must be inside the range
// [1,32].
func makeTreeCodec(bits int) treeCodec {
return treeCodec{makeProbTree(bits)}
}
// deepcopy initializes tc as a deep copy of the source.
func (tc *treeCodec) deepcopy(src *treeCodec) {
tc.probTree.deepcopy(&src.probTree)
}
// Encode uses the range encoder to encode a fixed-bit-size value.
func (tc *treeCodec) Encode(e *rangeEncoder, v uint32) (err error) {
m := uint32(1)
for i := int(tc.bits) - 1; i >= 0; i-- {
b := (v >> uint(i)) & 1
if err := e.EncodeBit(b, &tc.probs[m]); err != nil {
return err
}
m = (m << 1) | b
}
return nil
}
// Decodes uses the range decoder to decode a fixed-bit-size value. Errors may
// be caused by the range decoder.
func (tc *treeCodec) Decode(d *rangeDecoder) (v uint32, err error) {
m := uint32(1)
for j := 0; j < int(tc.bits); j++ {
b, err := d.DecodeBit(&tc.probs[m])
if err != nil {
return 0, err
}
m = (m << 1) | b
}
return m - (1 << uint(tc.bits)), nil
}
// treeReverseCodec is another tree codec, where the least-significant bit is
// the start of the probability tree.
type treeReverseCodec struct {
probTree
}
// deepcopy initializes the treeReverseCodec as a deep copy of the
// source.
func (tc *treeReverseCodec) deepcopy(src *treeReverseCodec) {
tc.probTree.deepcopy(&src.probTree)
}
// makeTreeReverseCodec creates treeReverseCodec value. The bits argument must
// be in the range [1,32].
func makeTreeReverseCodec(bits int) treeReverseCodec {
return treeReverseCodec{makeProbTree(bits)}
}
// Encode uses range encoder to encode a fixed-bit-size value. The range
// encoder may cause errors.
func (tc *treeReverseCodec) Encode(v uint32, e *rangeEncoder) (err error) {
m := uint32(1)
for i := uint(0); i < uint(tc.bits); i++ {
b := (v >> i) & 1
if err := e.EncodeBit(b, &tc.probs[m]); err != nil {
return err
}
m = (m << 1) | b
}
return nil
}
// Decodes uses the range decoder to decode a fixed-bit-size value. Errors
// returned by the range decoder will be returned.
func (tc *treeReverseCodec) Decode(d *rangeDecoder) (v uint32, err error) {
m := uint32(1)
for j := uint(0); j < uint(tc.bits); j++ {
b, err := d.DecodeBit(&tc.probs[m])
if err != nil {
return 0, err
}
m = (m << 1) | b
v |= b << j
}
return v, nil
}
// probTree stores enough probability values to be used by the treeEncode and
// treeDecode methods of the range coder types.
type probTree struct {
probs []prob
bits byte
}
// deepcopy initializes the probTree value as a deep copy of the source.
func (t *probTree) deepcopy(src *probTree) {
if t == src {
return
}
t.probs = make([]prob, len(src.probs))
copy(t.probs, src.probs)
t.bits = src.bits
}
// makeProbTree initializes a probTree structure.
func makeProbTree(bits int) probTree {
if !(1 <= bits && bits <= 32) {
panic("bits outside of range [1,32]")
}
t := probTree{
bits: byte(bits),
probs: make([]prob, 1<<uint(bits)),
}
for i := range t.probs {
t.probs[i] = probInit
}
return t
}
// Bits provides the number of bits for the values to de- or encode.
func (t *probTree) Bits() int {
return int(t.bits)
}

209
vendor/github.com/ulikunitz/xz/lzma/writer.go generated vendored Normal file
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// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package lzma
import (
"bufio"
"errors"
"io"
)
// MinDictCap and MaxDictCap provide the range of supported dictionary
// capacities.
const (
MinDictCap = 1 << 12
MaxDictCap = 1<<32 - 1
)
// WriterConfig defines the configuration parameter for a writer.
type WriterConfig struct {
// Properties for the encoding. If the it is nil the value
// {LC: 3, LP: 0, PB: 2} will be chosen.
Properties *Properties
// The capacity of the dictionary. If DictCap is zero, the value
// 8 MiB will be chosen.
DictCap int
// Size of the lookahead buffer; value 0 indicates default size
// 4096
BufSize int
// Match algorithm
Matcher MatchAlgorithm
// SizeInHeader indicates that the header will contain an
// explicit size.
SizeInHeader bool
// Size of the data to be encoded. A positive value will imply
// than an explicit size will be set in the header.
Size int64
// EOSMarker requests whether the EOSMarker needs to be written.
// If no explicit size is been given the EOSMarker will be
// set automatically.
EOSMarker bool
}
// fill converts zero-value fields to their explicit default values.
func (c *WriterConfig) fill() {
if c.Properties == nil {
c.Properties = &Properties{LC: 3, LP: 0, PB: 2}
}
if c.DictCap == 0 {
c.DictCap = 8 * 1024 * 1024
}
if c.BufSize == 0 {
c.BufSize = 4096
}
if c.Size > 0 {
c.SizeInHeader = true
}
if !c.SizeInHeader {
c.EOSMarker = true
}
}
// Verify checks WriterConfig for errors. Verify will replace zero
// values with default values.
func (c *WriterConfig) Verify() error {
c.fill()
var err error
if c == nil {
return errors.New("lzma: WriterConfig is nil")
}
if c.Properties == nil {
return errors.New("lzma: WriterConfig has no Properties set")
}
if err = c.Properties.verify(); err != nil {
return err
}
if !(MinDictCap <= c.DictCap && int64(c.DictCap) <= MaxDictCap) {
return errors.New("lzma: dictionary capacity is out of range")
}
if !(maxMatchLen <= c.BufSize) {
return errors.New("lzma: lookahead buffer size too small")
}
if c.SizeInHeader {
if c.Size < 0 {
return errors.New("lzma: negative size not supported")
}
} else if !c.EOSMarker {
return errors.New("lzma: EOS marker is required")
}
if err = c.Matcher.verify(); err != nil {
return err
}
return nil
}
// header returns the header structure for this configuration.
func (c *WriterConfig) header() header {
h := header{
properties: *c.Properties,
dictCap: c.DictCap,
size: -1,
}
if c.SizeInHeader {
h.size = c.Size
}
return h
}
// Writer writes an LZMA stream in the classic format.
type Writer struct {
h header
bw io.ByteWriter
buf *bufio.Writer
e *encoder
}
// NewWriter creates a new LZMA writer for the classic format. The
// method will write the header to the underlying stream.
func (c WriterConfig) NewWriter(lzma io.Writer) (w *Writer, err error) {
if err = c.Verify(); err != nil {
return nil, err
}
w = &Writer{h: c.header()}
var ok bool
w.bw, ok = lzma.(io.ByteWriter)
if !ok {
w.buf = bufio.NewWriter(lzma)
w.bw = w.buf
}
state := newState(w.h.properties)
m, err := c.Matcher.new(w.h.dictCap)
if err != nil {
return nil, err
}
dict, err := newEncoderDict(w.h.dictCap, c.BufSize, m)
if err != nil {
return nil, err
}
var flags encoderFlags
if c.EOSMarker {
flags = eosMarker
}
if w.e, err = newEncoder(w.bw, state, dict, flags); err != nil {
return nil, err
}
if err = w.writeHeader(); err != nil {
return nil, err
}
return w, nil
}
// NewWriter creates a new LZMA writer using the classic format. The
// function writes the header to the underlying stream.
func NewWriter(lzma io.Writer) (w *Writer, err error) {
return WriterConfig{}.NewWriter(lzma)
}
// writeHeader writes the LZMA header into the stream.
func (w *Writer) writeHeader() error {
data, err := w.h.marshalBinary()
if err != nil {
return err
}
_, err = w.bw.(io.Writer).Write(data)
return err
}
// Write puts data into the Writer.
func (w *Writer) Write(p []byte) (n int, err error) {
if w.h.size >= 0 {
m := w.h.size
m -= w.e.Compressed() + int64(w.e.dict.Buffered())
if m < 0 {
m = 0
}
if m < int64(len(p)) {
p = p[:m]
err = ErrNoSpace
}
}
var werr error
if n, werr = w.e.Write(p); werr != nil {
err = werr
}
return n, err
}
// Close closes the writer stream. It ensures that all data from the
// buffer will be compressed and the LZMA stream will be finished.
func (w *Writer) Close() error {
if w.h.size >= 0 {
n := w.e.Compressed() + int64(w.e.dict.Buffered())
if n != w.h.size {
return errSize
}
}
err := w.e.Close()
if w.buf != nil {
ferr := w.buf.Flush()
if err == nil {
err = ferr
}
}
return err
}

305
vendor/github.com/ulikunitz/xz/lzma/writer2.go generated vendored Normal file
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// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package lzma
import (
"bytes"
"errors"
"io"
)
// Writer2Config is used to create a Writer2 using parameters.
type Writer2Config struct {
// The properties for the encoding. If the it is nil the value
// {LC: 3, LP: 0, PB: 2} will be chosen.
Properties *Properties
// The capacity of the dictionary. If DictCap is zero, the value
// 8 MiB will be chosen.
DictCap int
// Size of the lookahead buffer; value 0 indicates default size
// 4096
BufSize int
// Match algorithm
Matcher MatchAlgorithm
}
// fill replaces zero values with default values.
func (c *Writer2Config) fill() {
if c.Properties == nil {
c.Properties = &Properties{LC: 3, LP: 0, PB: 2}
}
if c.DictCap == 0 {
c.DictCap = 8 * 1024 * 1024
}
if c.BufSize == 0 {
c.BufSize = 4096
}
}
// Verify checks the Writer2Config for correctness. Zero values will be
// replaced by default values.
func (c *Writer2Config) Verify() error {
c.fill()
var err error
if c == nil {
return errors.New("lzma: WriterConfig is nil")
}
if c.Properties == nil {
return errors.New("lzma: WriterConfig has no Properties set")
}
if err = c.Properties.verify(); err != nil {
return err
}
if !(MinDictCap <= c.DictCap && int64(c.DictCap) <= MaxDictCap) {
return errors.New("lzma: dictionary capacity is out of range")
}
if !(maxMatchLen <= c.BufSize) {
return errors.New("lzma: lookahead buffer size too small")
}
if c.Properties.LC+c.Properties.LP > 4 {
return errors.New("lzma: sum of lc and lp exceeds 4")
}
if err = c.Matcher.verify(); err != nil {
return err
}
return nil
}
// Writer2 supports the creation of an LZMA2 stream. But note that
// written data is buffered, so call Flush or Close to write data to the
// underlying writer. The Close method writes the end-of-stream marker
// to the stream. So you may be able to concatenate the output of two
// writers as long the output of the first writer has only been flushed
// but not closed.
//
// Any change to the fields Properties, DictCap must be done before the
// first call to Write, Flush or Close.
type Writer2 struct {
w io.Writer
start *state
encoder *encoder
cstate chunkState
ctype chunkType
buf bytes.Buffer
lbw LimitedByteWriter
}
// NewWriter2 creates an LZMA2 chunk sequence writer with the default
// parameters and options.
func NewWriter2(lzma2 io.Writer) (w *Writer2, err error) {
return Writer2Config{}.NewWriter2(lzma2)
}
// NewWriter2 creates a new LZMA2 writer using the given configuration.
func (c Writer2Config) NewWriter2(lzma2 io.Writer) (w *Writer2, err error) {
if err = c.Verify(); err != nil {
return nil, err
}
w = &Writer2{
w: lzma2,
start: newState(*c.Properties),
cstate: start,
ctype: start.defaultChunkType(),
}
w.buf.Grow(maxCompressed)
w.lbw = LimitedByteWriter{BW: &w.buf, N: maxCompressed}
m, err := c.Matcher.new(c.DictCap)
if err != nil {
return nil, err
}
d, err := newEncoderDict(c.DictCap, c.BufSize, m)
if err != nil {
return nil, err
}
w.encoder, err = newEncoder(&w.lbw, cloneState(w.start), d, 0)
if err != nil {
return nil, err
}
return w, nil
}
// written returns the number of bytes written to the current chunk
func (w *Writer2) written() int {
if w.encoder == nil {
return 0
}
return int(w.encoder.Compressed()) + w.encoder.dict.Buffered()
}
// errClosed indicates that the writer is closed.
var errClosed = errors.New("lzma: writer closed")
// Writes data to LZMA2 stream. Note that written data will be buffered.
// Use Flush or Close to ensure that data is written to the underlying
// writer.
func (w *Writer2) Write(p []byte) (n int, err error) {
if w.cstate == stop {
return 0, errClosed
}
for n < len(p) {
m := maxUncompressed - w.written()
if m <= 0 {
panic("lzma: maxUncompressed reached")
}
var q []byte
if n+m < len(p) {
q = p[n : n+m]
} else {
q = p[n:]
}
k, err := w.encoder.Write(q)
n += k
if err != nil && err != ErrLimit {
return n, err
}
if err == ErrLimit || k == m {
if err = w.flushChunk(); err != nil {
return n, err
}
}
}
return n, nil
}
// writeUncompressedChunk writes an uncompressed chunk to the LZMA2
// stream.
func (w *Writer2) writeUncompressedChunk() error {
u := w.encoder.Compressed()
if u <= 0 {
return errors.New("lzma: can't write empty uncompressed chunk")
}
if u > maxUncompressed {
panic("overrun of uncompressed data limit")
}
switch w.ctype {
case cLRND:
w.ctype = cUD
default:
w.ctype = cU
}
w.encoder.state = w.start
header := chunkHeader{
ctype: w.ctype,
uncompressed: uint32(u - 1),
}
hdata, err := header.MarshalBinary()
if err != nil {
return err
}
if _, err = w.w.Write(hdata); err != nil {
return err
}
_, err = w.encoder.dict.CopyN(w.w, int(u))
return err
}
// writeCompressedChunk writes a compressed chunk to the underlying
// writer.
func (w *Writer2) writeCompressedChunk() error {
if w.ctype == cU || w.ctype == cUD {
panic("chunk type uncompressed")
}
u := w.encoder.Compressed()
if u <= 0 {
return errors.New("writeCompressedChunk: empty chunk")
}
if u > maxUncompressed {
panic("overrun of uncompressed data limit")
}
c := w.buf.Len()
if c <= 0 {
panic("no compressed data")
}
if c > maxCompressed {
panic("overrun of compressed data limit")
}
header := chunkHeader{
ctype: w.ctype,
uncompressed: uint32(u - 1),
compressed: uint16(c - 1),
props: w.encoder.state.Properties,
}
hdata, err := header.MarshalBinary()
if err != nil {
return err
}
if _, err = w.w.Write(hdata); err != nil {
return err
}
_, err = io.Copy(w.w, &w.buf)
return err
}
// writes a single chunk to the underlying writer.
func (w *Writer2) writeChunk() error {
u := int(uncompressedHeaderLen + w.encoder.Compressed())
c := headerLen(w.ctype) + w.buf.Len()
if u < c {
return w.writeUncompressedChunk()
}
return w.writeCompressedChunk()
}
// flushChunk terminates the current chunk. The encoder will be reset
// to support the next chunk.
func (w *Writer2) flushChunk() error {
if w.written() == 0 {
return nil
}
var err error
if err = w.encoder.Close(); err != nil {
return err
}
if err = w.writeChunk(); err != nil {
return err
}
w.buf.Reset()
w.lbw.N = maxCompressed
if err = w.encoder.Reopen(&w.lbw); err != nil {
return err
}
if err = w.cstate.next(w.ctype); err != nil {
return err
}
w.ctype = w.cstate.defaultChunkType()
w.start = cloneState(w.encoder.state)
return nil
}
// Flush writes all buffered data out to the underlying stream. This
// could result in multiple chunks to be created.
func (w *Writer2) Flush() error {
if w.cstate == stop {
return errClosed
}
for w.written() > 0 {
if err := w.flushChunk(); err != nil {
return err
}
}
return nil
}
// Close terminates the LZMA2 stream with an EOS chunk.
func (w *Writer2) Close() error {
if w.cstate == stop {
return errClosed
}
if err := w.Flush(); err != nil {
return nil
}
// write zero byte EOS chunk
_, err := w.w.Write([]byte{0})
if err != nil {
return err
}
w.cstate = stop
return nil
}

117
vendor/github.com/ulikunitz/xz/lzmafilter.go generated vendored Normal file
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// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package xz
import (
"errors"
"fmt"
"io"
"github.com/ulikunitz/xz/lzma"
)
// LZMA filter constants.
const (
lzmaFilterID = 0x21
lzmaFilterLen = 3
)
// lzmaFilter declares the LZMA2 filter information stored in an xz
// block header.
type lzmaFilter struct {
dictCap int64
}
// String returns a representation of the LZMA filter.
func (f lzmaFilter) String() string {
return fmt.Sprintf("LZMA dict cap %#x", f.dictCap)
}
// id returns the ID for the LZMA2 filter.
func (f lzmaFilter) id() uint64 { return lzmaFilterID }
// MarshalBinary converts the lzmaFilter in its encoded representation.
func (f lzmaFilter) MarshalBinary() (data []byte, err error) {
c := lzma.EncodeDictCap(f.dictCap)
return []byte{lzmaFilterID, 1, c}, nil
}
// UnmarshalBinary unmarshals the given data representation of the LZMA2
// filter.
func (f *lzmaFilter) UnmarshalBinary(data []byte) error {
if len(data) != lzmaFilterLen {
return errors.New("xz: data for LZMA2 filter has wrong length")
}
if data[0] != lzmaFilterID {
return errors.New("xz: wrong LZMA2 filter id")
}
if data[1] != 1 {
return errors.New("xz: wrong LZMA2 filter size")
}
dc, err := lzma.DecodeDictCap(data[2])
if err != nil {
return errors.New("xz: wrong LZMA2 dictionary size property")
}
f.dictCap = dc
return nil
}
// reader creates a new reader for the LZMA2 filter.
func (f lzmaFilter) reader(r io.Reader, c *ReaderConfig) (fr io.Reader,
err error) {
config := new(lzma.Reader2Config)
if c != nil {
config.DictCap = c.DictCap
}
dc := int(f.dictCap)
if dc < 1 {
return nil, errors.New("xz: LZMA2 filter parameter " +
"dictionary capacity overflow")
}
if dc > config.DictCap {
config.DictCap = dc
}
fr, err = config.NewReader2(r)
if err != nil {
return nil, err
}
return fr, nil
}
// writeCloser creates a io.WriteCloser for the LZMA2 filter.
func (f lzmaFilter) writeCloser(w io.WriteCloser, c *WriterConfig,
) (fw io.WriteCloser, err error) {
config := new(lzma.Writer2Config)
if c != nil {
*config = lzma.Writer2Config{
Properties: c.Properties,
DictCap: c.DictCap,
BufSize: c.BufSize,
Matcher: c.Matcher,
}
}
dc := int(f.dictCap)
if dc < 1 {
return nil, errors.New("xz: LZMA2 filter parameter " +
"dictionary capacity overflow")
}
if dc > config.DictCap {
config.DictCap = dc
}
fw, err = config.NewWriter2(w)
if err != nil {
return nil, err
}
return fw, nil
}
// last returns true, because an LZMA2 filter must be the last filter in
// the filter list.
func (f lzmaFilter) last() bool { return true }

5
vendor/github.com/ulikunitz/xz/make-docs generated vendored Executable file
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#!/bin/sh
set -x
pandoc -t html5 -f markdown -s --css=doc/md.css -o README.html README.md
pandoc -t html5 -f markdown -s --css=doc/md.css -o TODO.html TODO.md

373
vendor/github.com/ulikunitz/xz/reader.go generated vendored Normal file
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// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Package xz supports the compression and decompression of xz files. It
// supports version 1.0.4 of the specification without the non-LZMA2
// filters. See http://tukaani.org/xz/xz-file-format-1.0.4.txt
package xz
import (
"bytes"
"errors"
"fmt"
"hash"
"io"
"github.com/ulikunitz/xz/internal/xlog"
"github.com/ulikunitz/xz/lzma"
)
// ReaderConfig defines the parameters for the xz reader. The
// SingleStream parameter requests the reader to assume that the
// underlying stream contains only a single stream.
type ReaderConfig struct {
DictCap int
SingleStream bool
}
// fill replaces all zero values with their default values.
func (c *ReaderConfig) fill() {
if c.DictCap == 0 {
c.DictCap = 8 * 1024 * 1024
}
}
// Verify checks the reader parameters for Validity. Zero values will be
// replaced by default values.
func (c *ReaderConfig) Verify() error {
if c == nil {
return errors.New("xz: reader parameters are nil")
}
lc := lzma.Reader2Config{DictCap: c.DictCap}
if err := lc.Verify(); err != nil {
return err
}
return nil
}
// Reader supports the reading of one or multiple xz streams.
type Reader struct {
ReaderConfig
xz io.Reader
sr *streamReader
}
// streamReader decodes a single xz stream
type streamReader struct {
ReaderConfig
xz io.Reader
br *blockReader
newHash func() hash.Hash
h header
index []record
}
// NewReader creates a new xz reader using the default parameters.
// The function reads and checks the header of the first XZ stream. The
// reader will process multiple streams including padding.
func NewReader(xz io.Reader) (r *Reader, err error) {
return ReaderConfig{}.NewReader(xz)
}
// NewReader creates an xz stream reader. The created reader will be
// able to process multiple streams and padding unless a SingleStream
// has been set in the reader configuration c.
func (c ReaderConfig) NewReader(xz io.Reader) (r *Reader, err error) {
if err = c.Verify(); err != nil {
return nil, err
}
r = &Reader{
ReaderConfig: c,
xz: xz,
}
if r.sr, err = c.newStreamReader(xz); err != nil {
if err == io.EOF {
err = io.ErrUnexpectedEOF
}
return nil, err
}
return r, nil
}
var errUnexpectedData = errors.New("xz: unexpected data after stream")
// Read reads uncompressed data from the stream.
func (r *Reader) Read(p []byte) (n int, err error) {
for n < len(p) {
if r.sr == nil {
if r.SingleStream {
data := make([]byte, 1)
_, err = io.ReadFull(r.xz, data)
if err != io.EOF {
return n, errUnexpectedData
}
return n, io.EOF
}
for {
r.sr, err = r.ReaderConfig.newStreamReader(r.xz)
if err != errPadding {
break
}
}
if err != nil {
return n, err
}
}
k, err := r.sr.Read(p[n:])
n += k
if err != nil {
if err == io.EOF {
r.sr = nil
continue
}
return n, err
}
}
return n, nil
}
var errPadding = errors.New("xz: padding (4 zero bytes) encountered")
// newStreamReader creates a new xz stream reader using the given configuration
// parameters. NewReader reads and checks the header of the xz stream.
func (c ReaderConfig) newStreamReader(xz io.Reader) (r *streamReader, err error) {
if err = c.Verify(); err != nil {
return nil, err
}
data := make([]byte, HeaderLen)
if _, err := io.ReadFull(xz, data[:4]); err != nil {
return nil, err
}
if bytes.Equal(data[:4], []byte{0, 0, 0, 0}) {
return nil, errPadding
}
if _, err = io.ReadFull(xz, data[4:]); err != nil {
if err == io.EOF {
err = io.ErrUnexpectedEOF
}
return nil, err
}
r = &streamReader{
ReaderConfig: c,
xz: xz,
index: make([]record, 0, 4),
}
if err = r.h.UnmarshalBinary(data); err != nil {
return nil, err
}
xlog.Debugf("xz header %s", r.h)
if r.newHash, err = newHashFunc(r.h.flags); err != nil {
return nil, err
}
return r, nil
}
// errIndex indicates an error with the xz file index.
var errIndex = errors.New("xz: error in xz file index")
// readTail reads the index body and the xz footer.
func (r *streamReader) readTail() error {
index, n, err := readIndexBody(r.xz)
if err != nil {
if err == io.EOF {
err = io.ErrUnexpectedEOF
}
return err
}
if len(index) != len(r.index) {
return fmt.Errorf("xz: index length is %d; want %d",
len(index), len(r.index))
}
for i, rec := range r.index {
if rec != index[i] {
return fmt.Errorf("xz: record %d is %v; want %v",
i, rec, index[i])
}
}
p := make([]byte, footerLen)
if _, err = io.ReadFull(r.xz, p); err != nil {
if err == io.EOF {
err = io.ErrUnexpectedEOF
}
return err
}
var f footer
if err = f.UnmarshalBinary(p); err != nil {
return err
}
xlog.Debugf("xz footer %s", f)
if f.flags != r.h.flags {
return errors.New("xz: footer flags incorrect")
}
if f.indexSize != int64(n)+1 {
return errors.New("xz: index size in footer wrong")
}
return nil
}
// Read reads actual data from the xz stream.
func (r *streamReader) Read(p []byte) (n int, err error) {
for n < len(p) {
if r.br == nil {
bh, hlen, err := readBlockHeader(r.xz)
if err != nil {
if err == errIndexIndicator {
if err = r.readTail(); err != nil {
return n, err
}
return n, io.EOF
}
return n, err
}
xlog.Debugf("block %v", *bh)
r.br, err = r.ReaderConfig.newBlockReader(r.xz, bh,
hlen, r.newHash())
if err != nil {
return n, err
}
}
k, err := r.br.Read(p[n:])
n += k
if err != nil {
if err == io.EOF {
r.index = append(r.index, r.br.record())
r.br = nil
} else {
return n, err
}
}
}
return n, nil
}
// countingReader is a reader that counts the bytes read.
type countingReader struct {
r io.Reader
n int64
}
// Read reads data from the wrapped reader and adds it to the n field.
func (lr *countingReader) Read(p []byte) (n int, err error) {
n, err = lr.r.Read(p)
lr.n += int64(n)
return n, err
}
// blockReader supports the reading of a block.
type blockReader struct {
lxz countingReader
header *blockHeader
headerLen int
n int64
hash hash.Hash
r io.Reader
err error
}
// newBlockReader creates a new block reader.
func (c *ReaderConfig) newBlockReader(xz io.Reader, h *blockHeader,
hlen int, hash hash.Hash) (br *blockReader, err error) {
br = &blockReader{
lxz: countingReader{r: xz},
header: h,
headerLen: hlen,
hash: hash,
}
fr, err := c.newFilterReader(&br.lxz, h.filters)
if err != nil {
return nil, err
}
br.r = io.TeeReader(fr, br.hash)
return br, nil
}
// uncompressedSize returns the uncompressed size of the block.
func (br *blockReader) uncompressedSize() int64 {
return br.n
}
// compressedSize returns the compressed size of the block.
func (br *blockReader) compressedSize() int64 {
return br.lxz.n
}
// unpaddedSize computes the unpadded size for the block.
func (br *blockReader) unpaddedSize() int64 {
n := int64(br.headerLen)
n += br.compressedSize()
n += int64(br.hash.Size())
return n
}
// record returns the index record for the current block.
func (br *blockReader) record() record {
return record{br.unpaddedSize(), br.uncompressedSize()}
}
// errBlockSize indicates that the size of the block in the block header
// is wrong.
var errBlockSize = errors.New("xz: wrong uncompressed size for block")
// Read reads data from the block.
func (br *blockReader) Read(p []byte) (n int, err error) {
n, err = br.r.Read(p)
br.n += int64(n)
u := br.header.uncompressedSize
if u >= 0 && br.uncompressedSize() > u {
return n, errors.New("xz: wrong uncompressed size for block")
}
c := br.header.compressedSize
if c >= 0 && br.compressedSize() > c {
return n, errors.New("xz: wrong compressed size for block")
}
if err != io.EOF {
return n, err
}
if br.uncompressedSize() < u || br.compressedSize() < c {
return n, io.ErrUnexpectedEOF
}
s := br.hash.Size()
k := padLen(br.lxz.n)
q := make([]byte, k+s, k+2*s)
if _, err = io.ReadFull(br.lxz.r, q); err != nil {
if err == io.EOF {
err = io.ErrUnexpectedEOF
}
return n, err
}
if !allZeros(q[:k]) {
return n, errors.New("xz: non-zero block padding")
}
checkSum := q[k:]
computedSum := br.hash.Sum(checkSum[s:])
if !bytes.Equal(checkSum, computedSum) {
return n, errors.New("xz: checksum error for block")
}
return n, io.EOF
}
func (c *ReaderConfig) newFilterReader(r io.Reader, f []filter) (fr io.Reader,
err error) {
if err = verifyFilters(f); err != nil {
return nil, err
}
fr = r
for i := len(f) - 1; i >= 0; i-- {
fr, err = f[i].reader(fr, c)
if err != nil {
return nil, err
}
}
return fr, nil
}

386
vendor/github.com/ulikunitz/xz/writer.go generated vendored Normal file
View File

@ -0,0 +1,386 @@
// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package xz
import (
"errors"
"hash"
"io"
"github.com/ulikunitz/xz/lzma"
)
// WriterConfig describe the parameters for an xz writer.
type WriterConfig struct {
Properties *lzma.Properties
DictCap int
BufSize int
BlockSize int64
// checksum method: CRC32, CRC64 or SHA256
CheckSum byte
// match algorithm
Matcher lzma.MatchAlgorithm
}
// fill replaces zero values with default values.
func (c *WriterConfig) fill() {
if c.Properties == nil {
c.Properties = &lzma.Properties{LC: 3, LP: 0, PB: 2}
}
if c.DictCap == 0 {
c.DictCap = 8 * 1024 * 1024
}
if c.BufSize == 0 {
c.BufSize = 4096
}
if c.BlockSize == 0 {
c.BlockSize = maxInt64
}
if c.CheckSum == 0 {
c.CheckSum = CRC64
}
}
// Verify checks the configuration for errors. Zero values will be
// replaced by default values.
func (c *WriterConfig) Verify() error {
if c == nil {
return errors.New("xz: writer configuration is nil")
}
c.fill()
lc := lzma.Writer2Config{
Properties: c.Properties,
DictCap: c.DictCap,
BufSize: c.BufSize,
Matcher: c.Matcher,
}
if err := lc.Verify(); err != nil {
return err
}
if c.BlockSize <= 0 {
return errors.New("xz: block size out of range")
}
if err := verifyFlags(c.CheckSum); err != nil {
return err
}
return nil
}
// filters creates the filter list for the given parameters.
func (c *WriterConfig) filters() []filter {
return []filter{&lzmaFilter{int64(c.DictCap)}}
}
// maxInt64 defines the maximum 64-bit signed integer.
const maxInt64 = 1<<63 - 1
// verifyFilters checks the filter list for the length and the right
// sequence of filters.
func verifyFilters(f []filter) error {
if len(f) == 0 {
return errors.New("xz: no filters")
}
if len(f) > 4 {
return errors.New("xz: more than four filters")
}
for _, g := range f[:len(f)-1] {
if g.last() {
return errors.New("xz: last filter is not last")
}
}
if !f[len(f)-1].last() {
return errors.New("xz: wrong last filter")
}
return nil
}
// newFilterWriteCloser converts a filter list into a WriteCloser that
// can be used by a blockWriter.
func (c *WriterConfig) newFilterWriteCloser(w io.Writer, f []filter) (fw io.WriteCloser, err error) {
if err = verifyFilters(f); err != nil {
return nil, err
}
fw = nopWriteCloser(w)
for i := len(f) - 1; i >= 0; i-- {
fw, err = f[i].writeCloser(fw, c)
if err != nil {
return nil, err
}
}
return fw, nil
}
// nopWCloser implements a WriteCloser with a Close method not doing
// anything.
type nopWCloser struct {
io.Writer
}
// Close returns nil and doesn't do anything else.
func (c nopWCloser) Close() error {
return nil
}
// nopWriteCloser converts the Writer into a WriteCloser with a Close
// function that does nothing beside returning nil.
func nopWriteCloser(w io.Writer) io.WriteCloser {
return nopWCloser{w}
}
// Writer compresses data written to it. It is an io.WriteCloser.
type Writer struct {
WriterConfig
xz io.Writer
bw *blockWriter
newHash func() hash.Hash
h header
index []record
closed bool
}
// newBlockWriter creates a new block writer writes the header out.
func (w *Writer) newBlockWriter() error {
var err error
w.bw, err = w.WriterConfig.newBlockWriter(w.xz, w.newHash())
if err != nil {
return err
}
if err = w.bw.writeHeader(w.xz); err != nil {
return err
}
return nil
}
// closeBlockWriter closes a block writer and records the sizes in the
// index.
func (w *Writer) closeBlockWriter() error {
var err error
if err = w.bw.Close(); err != nil {
return err
}
w.index = append(w.index, w.bw.record())
return nil
}
// NewWriter creates a new xz writer using default parameters.
func NewWriter(xz io.Writer) (w *Writer, err error) {
return WriterConfig{}.NewWriter(xz)
}
// NewWriter creates a new Writer using the given configuration parameters.
func (c WriterConfig) NewWriter(xz io.Writer) (w *Writer, err error) {
if err = c.Verify(); err != nil {
return nil, err
}
w = &Writer{
WriterConfig: c,
xz: xz,
h: header{c.CheckSum},
index: make([]record, 0, 4),
}
if w.newHash, err = newHashFunc(c.CheckSum); err != nil {
return nil, err
}
data, err := w.h.MarshalBinary()
if _, err = xz.Write(data); err != nil {
return nil, err
}
if err = w.newBlockWriter(); err != nil {
return nil, err
}
return w, nil
}
// Write compresses the uncompressed data provided.
func (w *Writer) Write(p []byte) (n int, err error) {
if w.closed {
return 0, errClosed
}
for {
k, err := w.bw.Write(p[n:])
n += k
if err != errNoSpace {
return n, err
}
if err = w.closeBlockWriter(); err != nil {
return n, err
}
if err = w.newBlockWriter(); err != nil {
return n, err
}
}
}
// Close closes the writer and adds the footer to the Writer. Close
// doesn't close the underlying writer.
func (w *Writer) Close() error {
if w.closed {
return errClosed
}
w.closed = true
var err error
if err = w.closeBlockWriter(); err != nil {
return err
}
f := footer{flags: w.h.flags}
if f.indexSize, err = writeIndex(w.xz, w.index); err != nil {
return err
}
data, err := f.MarshalBinary()
if err != nil {
return err
}
if _, err = w.xz.Write(data); err != nil {
return err
}
return nil
}
// countingWriter is a writer that counts all data written to it.
type countingWriter struct {
w io.Writer
n int64
}
// Write writes data to the countingWriter.
func (cw *countingWriter) Write(p []byte) (n int, err error) {
n, err = cw.w.Write(p)
cw.n += int64(n)
if err == nil && cw.n < 0 {
return n, errors.New("xz: counter overflow")
}
return
}
// blockWriter is writes a single block.
type blockWriter struct {
cxz countingWriter
// mw combines io.WriteCloser w and the hash.
mw io.Writer
w io.WriteCloser
n int64
blockSize int64
closed bool
headerLen int
filters []filter
hash hash.Hash
}
// newBlockWriter creates a new block writer.
func (c *WriterConfig) newBlockWriter(xz io.Writer, hash hash.Hash) (bw *blockWriter, err error) {
bw = &blockWriter{
cxz: countingWriter{w: xz},
blockSize: c.BlockSize,
filters: c.filters(),
hash: hash,
}
bw.w, err = c.newFilterWriteCloser(&bw.cxz, bw.filters)
if err != nil {
return nil, err
}
bw.mw = io.MultiWriter(bw.w, bw.hash)
return bw, nil
}
// writeHeader writes the header. If the function is called after Close
// the commpressedSize and uncompressedSize fields will be filled.
func (bw *blockWriter) writeHeader(w io.Writer) error {
h := blockHeader{
compressedSize: -1,
uncompressedSize: -1,
filters: bw.filters,
}
if bw.closed {
h.compressedSize = bw.compressedSize()
h.uncompressedSize = bw.uncompressedSize()
}
data, err := h.MarshalBinary()
if err != nil {
return err
}
if _, err = w.Write(data); err != nil {
return err
}
bw.headerLen = len(data)
return nil
}
// compressed size returns the amount of data written to the underlying
// stream.
func (bw *blockWriter) compressedSize() int64 {
return bw.cxz.n
}
// uncompressedSize returns the number of data written to the
// blockWriter
func (bw *blockWriter) uncompressedSize() int64 {
return bw.n
}
// unpaddedSize returns the sum of the header length, the uncompressed
// size of the block and the hash size.
func (bw *blockWriter) unpaddedSize() int64 {
if bw.headerLen <= 0 {
panic("xz: block header not written")
}
n := int64(bw.headerLen)
n += bw.compressedSize()
n += int64(bw.hash.Size())
return n
}
// record returns the record for the current stream. Call Close before
// calling this method.
func (bw *blockWriter) record() record {
return record{bw.unpaddedSize(), bw.uncompressedSize()}
}
var errClosed = errors.New("xz: writer already closed")
var errNoSpace = errors.New("xz: no space")
// Write writes uncompressed data to the block writer.
func (bw *blockWriter) Write(p []byte) (n int, err error) {
if bw.closed {
return 0, errClosed
}
t := bw.blockSize - bw.n
if int64(len(p)) > t {
err = errNoSpace
p = p[:t]
}
var werr error
n, werr = bw.mw.Write(p)
bw.n += int64(n)
if werr != nil {
return n, werr
}
return n, err
}
// Close closes the writer.
func (bw *blockWriter) Close() error {
if bw.closed {
return errClosed
}
bw.closed = true
if err := bw.w.Close(); err != nil {
return err
}
s := bw.hash.Size()
k := padLen(bw.cxz.n)
p := make([]byte, k+s)
bw.hash.Sum(p[k:k])
if _, err := bw.cxz.w.Write(p); err != nil {
return err
}
return nil
}

26
vendor/vendor.json vendored
View File

@ -1299,7 +1299,7 @@
"revisionTime": "2018-03-05T22:44:21Z"
},
{
"checksumSHA1": "hU3ibLi5mZBayj0HPIVpcMSvRgU=",
"checksumSHA1": "ByFN6xh/YGP/D3DM9c8p0D9D1XM=",
"path": "github.com/sirupsen/logrus",
"revision": "90150a8ed11b6ce285e77e8af2b0109559ce4777",
"revisionTime": "2018-03-15T01:07:03Z"
@ -1336,6 +1336,30 @@
"path": "github.com/ugorji/go/codec/codecgen",
"revision": "646ae4a518c1c3be0739df898118d9bccf993858"
},
{
"checksumSHA1": "amJo1E3F0QxcfxSt+FxDiQbR1wU=",
"path": "github.com/ulikunitz/xz",
"revision": "636d36a76670e6c700f22fd5f4588679ff2896c4",
"revisionTime": "2018-07-03T11:21:13Z"
},
{
"checksumSHA1": "vjnTkzNrMs5Xj6so/fq0mQ6dT1c=",
"path": "github.com/ulikunitz/xz/internal/hash",
"revision": "636d36a76670e6c700f22fd5f4588679ff2896c4",
"revisionTime": "2018-07-03T11:21:13Z"
},
{
"checksumSHA1": "m0pm57ASBK/CTdmC0ppRHO17mBs=",
"path": "github.com/ulikunitz/xz/internal/xlog",
"revision": "636d36a76670e6c700f22fd5f4588679ff2896c4",
"revisionTime": "2018-07-03T11:21:13Z"
},
{
"checksumSHA1": "2vZw6zc8xuNlyVz2QKvdlNSZQ1U=",
"path": "github.com/ulikunitz/xz/lzma",
"revision": "636d36a76670e6c700f22fd5f4588679ff2896c4",
"revisionTime": "2018-07-03T11:21:13Z"
},
{
"checksumSHA1": "AGBqaHqBx5wJdVRsQt4GeawjbXA=",
"path": "github.com/vmware/govmomi",