1 files changed, 373 insertions, 0 deletions
diff --git a/vendor/github.com/ulikunitz/xz/reader.go b/vendor/github.com/ulikunitz/xz/reader.go
new file mode 100644
index 000000000..0634c6bcc
--- /dev/null
+++ b/vendor/github.com/ulikunitz/xz/reader.go
@@ -0,0 +1,373 @@
+// 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
+}