vendor: adding tar-split dependency for graph

tar-split is a facility to disassemble and reassemble tar archives

Signed-off-by: Vincent Batts <vbatts@redhat.com>

hack/vendor.sh

@@ -33,8 +33,9 @@ clone git github.com/samuel/go-zookeeper d0e0d8e11f318e000a8cc434616d69e329edc37
 clone git github.com/coreos/go-etcd v2.0.0
 clone git github.com/hashicorp/consul v0.5.2
 
-# get distribution packages
+# get graph and distribution packages
 clone git github.com/docker/distribution 419bbc2da637d9b2a812be78ef8436df7caac70d
+clone git github.com/vbatts/tar-split v0.9.4
 
 clone git github.com/opencontainers/runc v0.0.2 # libcontainer
 # libcontainer deps (see src/github.com/docker/libcontainer/update-vendor.sh)

vendor/src/github.com/vbatts/tar-split/.travis.yml

@@ -0,0 +1,13 @@
+language: go
+go:
+  - 1.4.2
+  - 1.3.3
+
+# let us have pretty, fast Docker-based Travis workers!
+sudo: false
+
+# we don't need "go get" here <3
+install: go get -d ./...
+
+script:
+  - go test -v ./...

vendor/src/github.com/vbatts/tar-split/DESIGN.md

@@ -0,0 +1,36 @@
+Flow of TAR stream
+==================
+
+The underlying use of `github.com/vbatts/tar-split/archive/tar` is most similar
+to stdlib.
+
+
+Packer interface
+----------------
+
+For ease of storage and usage of the raw bytes, there will be a storage
+interface, that accepts an io.Writer (This way you could pass it an in memory
+buffer or a file handle).
+
+Having a Packer interface can allow configuration of hash.Hash for file payloads
+and providing your own io.Writer.
+
+Instead of having a state directory to store all the header information for all
+Readers, we will leave that up to user of Reader. Because we can not assume an
+ID for each Reader, and keeping that information differentiated.
+
+
+
+State Directory
+---------------
+
+Perhaps we could deduplicate the header info, by hashing the rawbytes and
+storing them in a directory tree like:
+
+	./ac/dc/beef
+
+Then reference the hash of the header info, in the positional records for the
+tar stream. Though this could be a future feature, and not required for an
+initial implementation. Also, this would imply an owned state directory, rather
+than just writing storage info to an io.Writer.
+

vendor/src/github.com/vbatts/tar-split/LICENSE

@@ -0,0 +1,19 @@
+Copyright (c) 2015 Vincent Batts, Raleigh, NC, USA
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.

vendor/src/github.com/vbatts/tar-split/README.md

@@ -0,0 +1,181 @@
+tar-split
+========
+
+[![Build Status](https://travis-ci.org/vbatts/tar-split.svg?branch=master)](https://travis-ci.org/vbatts/tar-split)
+
+Extend the upstream golang stdlib `archive/tar` library, to expose the raw
+bytes of the TAR, rather than just the marshalled headers and file stream.
+
+The goal being that by preserving the raw bytes of each header, padding bytes,
+and the raw file payload, one could reassemble the original archive.
+
+
+Docs
+----
+
+* https://godoc.org/github.com/vbatts/tar-split/tar/asm
+* https://godoc.org/github.com/vbatts/tar-split/tar/storage
+* https://godoc.org/github.com/vbatts/tar-split/archive/tar
+
+
+Caveat
+------
+
+Eventually this should detect TARs that this is not possible with.
+
+For example stored sparse files that have "holes" in them, will be read as a
+contiguous file, though the archive contents may be recorded in sparse format.
+Therefore when adding the file payload to a reassembled tar, to achieve
+identical output, the file payload would need be precisely re-sparsified. This
+is not something I seek to fix imediately, but would rather have an alert that
+precise reassembly is not possible.
+(see more http://www.gnu.org/software/tar/manual/html_node/Sparse-Formats.html)
+
+
+Other caveat, while tar archives support having multiple file entries for the
+same path, we will not support this feature. If there are more than one entries
+with the same path, expect an err (like `ErrDuplicatePath`) or a resulting tar
+stream that does not validate your original checksum/signature.
+
+
+Contract
+--------
+
+Do not break the API of stdlib `archive/tar` in our fork (ideally find an
+upstream mergeable solution)
+
+
+Std Version
+-----------
+
+The version of golang stdlib `archive/tar` is from go1.4.1, and their master branch around [a9dddb53f](https://github.com/golang/go/tree/a9dddb53f)
+
+
+Example
+-------
+
+First we'll get an archive to work with. For repeatability, we'll make an
+archive from what you've just cloned:
+
+```
+git archive --format=tar -o tar-split.tar HEAD .
+```
+
+Then build the example main.go:
+
+```
+go build ./main.go
+```
+
+Now run the example over the archive:
+
+```
+$ ./main tar-split.tar
+2015/02/20 15:00:58 writing "tar-split.tar" to "tar-split.tar.out"
+pax_global_header pre: 512 read: 52
+.travis.yml pre: 972 read: 374
+DESIGN.md pre: 650 read: 1131
+LICENSE pre: 917 read: 1075
+README.md pre: 973 read: 4289
+archive/ pre: 831 read: 0
+archive/tar/ pre: 512 read: 0
+archive/tar/common.go pre: 512 read: 7790
+[...]
+tar/storage/entry_test.go pre: 667 read: 1137
+tar/storage/getter.go pre: 911 read: 2741
+tar/storage/getter_test.go pre: 843 read: 1491
+tar/storage/packer.go pre: 557 read: 3141
+tar/storage/packer_test.go pre: 955 read: 3096
+EOF padding: 1512
+Remainder: 512
+Size: 215040; Sum: 215040
+```
+
+*What are we seeing here?* 
+
+* `pre` is the header of a file entry, and potentially the padding from the
+  end of the prior file's payload. Also with particular tar extensions and pax
+  attributes, the header can exceed 512 bytes.
+* `read` is the size of the file payload from the entry
+* `EOF padding` is the expected 1024 null bytes on the end of a tar archive,
+  plus potential padding from the end of the prior file entry's payload
+* `Remainder` is the remaining bytes of an archive. This is typically deadspace
+  as most tar implmentations will return after having reached the end of the
+  1024 null bytes. Though various implementations will include some amount of
+  bytes here, which will affect the checksum of the resulting tar archive,
+  therefore this must be accounted for as well.
+
+Ideally the input tar and output `*.out`, will match:
+
+```
+$ sha1sum tar-split.tar*
+ca9e19966b892d9ad5960414abac01ef585a1e22  tar-split.tar
+ca9e19966b892d9ad5960414abac01ef585a1e22  tar-split.tar.out
+```
+
+
+Stored Metadata
+---------------
+
+Since the raw bytes of the headers and padding are stored, you may be wondering
+what the size implications are. The headers are at least 512 bytes per
+file (sometimes more), at least 1024 null bytes on the end, and then various
+padding. This makes for a constant linear growth in the stored metadata, with a
+naive storage implementation.
+
+Reusing our prior example's `tar-split.tar`, let's build the checksize.go example:
+
+```
+go build ./checksize.go
+```
+
+```
+$ ./checksize ./tar-split.tar
+inspecting "tar-split.tar" (size 210k)
+ -- number of files: 50
+ -- size of metadata uncompressed: 53k
+ -- size of gzip compressed metadata: 3k
+```
+
+So assuming you've managed the extraction of the archive yourself, for reuse of
+the file payloads from a relative path, then the only additional storage
+implications are as little as 3kb.
+
+But let's look at a larger archive, with many files.
+
+```
+$ ls -sh ./d.tar
+1.4G ./d.tar
+$ ./checksize ~/d.tar 
+inspecting "/home/vbatts/d.tar" (size 1420749k)
+ -- number of files: 38718
+ -- size of metadata uncompressed: 43261k
+ -- size of gzip compressed metadata: 2251k
+```
+
+Here, an archive with 38,718 files has a compressed footprint of about 2mb.
+
+Rolling the null bytes on the end of the archive, we will assume a
+bytes-per-file rate for the storage implications.
+
+| uncompressed | compressed |
+| :----------: | :--------: |
+| ~ 1kb per/file | 0.06kb per/file |
+
+
+What's Next?
+------------
+
+* More implementations of storage Packer and Unpacker
+ - could be a redis or mongo backend
+* More implementations of FileGetter and FilePutter
+ - could be a redis or mongo backend
+* cli tooling to assemble/disassemble a provided tar archive
+* would be interesting to have an assembler stream that implements `io.Seeker`
+
+License
+-------
+
+See LICENSE
+
+

vendor/src/github.com/vbatts/tar-split/archive/tar/common.go

@@ -0,0 +1,305 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package tar implements access to tar archives.
+// It aims to cover most of the variations, including those produced
+// by GNU and BSD tars.
+//
+// References:
+//   http://www.freebsd.org/cgi/man.cgi?query=tar&sektion=5
+//   http://www.gnu.org/software/tar/manual/html_node/Standard.html
+//   http://pubs.opengroup.org/onlinepubs/9699919799/utilities/pax.html
+package tar
+
+import (
+	"bytes"
+	"errors"
+	"fmt"
+	"os"
+	"path"
+	"time"
+)
+
+const (
+	blockSize = 512
+
+	// Types
+	TypeReg           = '0'    // regular file
+	TypeRegA          = '\x00' // regular file
+	TypeLink          = '1'    // hard link
+	TypeSymlink       = '2'    // symbolic link
+	TypeChar          = '3'    // character device node
+	TypeBlock         = '4'    // block device node
+	TypeDir           = '5'    // directory
+	TypeFifo          = '6'    // fifo node
+	TypeCont          = '7'    // reserved
+	TypeXHeader       = 'x'    // extended header
+	TypeXGlobalHeader = 'g'    // global extended header
+	TypeGNULongName   = 'L'    // Next file has a long name
+	TypeGNULongLink   = 'K'    // Next file symlinks to a file w/ a long name
+	TypeGNUSparse     = 'S'    // sparse file
+)
+
+// A Header represents a single header in a tar archive.
+// Some fields may not be populated.
+type Header struct {
+	Name       string    // name of header file entry
+	Mode       int64     // permission and mode bits
+	Uid        int       // user id of owner
+	Gid        int       // group id of owner
+	Size       int64     // length in bytes
+	ModTime    time.Time // modified time
+	Typeflag   byte      // type of header entry
+	Linkname   string    // target name of link
+	Uname      string    // user name of owner
+	Gname      string    // group name of owner
+	Devmajor   int64     // major number of character or block device
+	Devminor   int64     // minor number of character or block device
+	AccessTime time.Time // access time
+	ChangeTime time.Time // status change time
+	Xattrs     map[string]string
+}
+
+// File name constants from the tar spec.
+const (
+	fileNameSize       = 100 // Maximum number of bytes in a standard tar name.
+	fileNamePrefixSize = 155 // Maximum number of ustar extension bytes.
+)
+
+// FileInfo returns an os.FileInfo for the Header.
+func (h *Header) FileInfo() os.FileInfo {
+	return headerFileInfo{h}
+}
+
+// headerFileInfo implements os.FileInfo.
+type headerFileInfo struct {
+	h *Header
+}
+
+func (fi headerFileInfo) Size() int64        { return fi.h.Size }
+func (fi headerFileInfo) IsDir() bool        { return fi.Mode().IsDir() }
+func (fi headerFileInfo) ModTime() time.Time { return fi.h.ModTime }
+func (fi headerFileInfo) Sys() interface{}   { return fi.h }
+
+// Name returns the base name of the file.
+func (fi headerFileInfo) Name() string {
+	if fi.IsDir() {
+		return path.Base(path.Clean(fi.h.Name))
+	}
+	return path.Base(fi.h.Name)
+}
+
+// Mode returns the permission and mode bits for the headerFileInfo.
+func (fi headerFileInfo) Mode() (mode os.FileMode) {
+	// Set file permission bits.
+	mode = os.FileMode(fi.h.Mode).Perm()
+
+	// Set setuid, setgid and sticky bits.
+	if fi.h.Mode&c_ISUID != 0 {
+		// setuid
+		mode |= os.ModeSetuid
+	}
+	if fi.h.Mode&c_ISGID != 0 {
+		// setgid
+		mode |= os.ModeSetgid
+	}
+	if fi.h.Mode&c_ISVTX != 0 {
+		// sticky
+		mode |= os.ModeSticky
+	}
+
+	// Set file mode bits.
+	// clear perm, setuid, setgid and sticky bits.
+	m := os.FileMode(fi.h.Mode) &^ 07777
+	if m == c_ISDIR {
+		// directory
+		mode |= os.ModeDir
+	}
+	if m == c_ISFIFO {
+		// named pipe (FIFO)
+		mode |= os.ModeNamedPipe
+	}
+	if m == c_ISLNK {
+		// symbolic link
+		mode |= os.ModeSymlink
+	}
+	if m == c_ISBLK {
+		// device file
+		mode |= os.ModeDevice
+	}
+	if m == c_ISCHR {
+		// Unix character device
+		mode |= os.ModeDevice
+		mode |= os.ModeCharDevice
+	}
+	if m == c_ISSOCK {
+		// Unix domain socket
+		mode |= os.ModeSocket
+	}
+
+	switch fi.h.Typeflag {
+	case TypeLink, TypeSymlink:
+		// hard link, symbolic link
+		mode |= os.ModeSymlink
+	case TypeChar:
+		// character device node
+		mode |= os.ModeDevice
+		mode |= os.ModeCharDevice
+	case TypeBlock:
+		// block device node
+		mode |= os.ModeDevice
+	case TypeDir:
+		// directory
+		mode |= os.ModeDir
+	case TypeFifo:
+		// fifo node
+		mode |= os.ModeNamedPipe
+	}
+
+	return mode
+}
+
+// sysStat, if non-nil, populates h from system-dependent fields of fi.
+var sysStat func(fi os.FileInfo, h *Header) error
+
+// Mode constants from the tar spec.
+const (
+	c_ISUID  = 04000   // Set uid
+	c_ISGID  = 02000   // Set gid
+	c_ISVTX  = 01000   // Save text (sticky bit)
+	c_ISDIR  = 040000  // Directory
+	c_ISFIFO = 010000  // FIFO
+	c_ISREG  = 0100000 // Regular file
+	c_ISLNK  = 0120000 // Symbolic link
+	c_ISBLK  = 060000  // Block special file
+	c_ISCHR  = 020000  // Character special file
+	c_ISSOCK = 0140000 // Socket
+)
+
+// Keywords for the PAX Extended Header
+const (
+	paxAtime    = "atime"
+	paxCharset  = "charset"
+	paxComment  = "comment"
+	paxCtime    = "ctime" // please note that ctime is not a valid pax header.
+	paxGid      = "gid"
+	paxGname    = "gname"
+	paxLinkpath = "linkpath"
+	paxMtime    = "mtime"
+	paxPath     = "path"
+	paxSize     = "size"
+	paxUid      = "uid"
+	paxUname    = "uname"
+	paxXattr    = "SCHILY.xattr."
+	paxNone     = ""
+)
+
+// FileInfoHeader creates a partially-populated Header from fi.
+// If fi describes a symlink, FileInfoHeader records link as the link target.
+// If fi describes a directory, a slash is appended to the name.
+// Because os.FileInfo's Name method returns only the base name of
+// the file it describes, it may be necessary to modify the Name field
+// of the returned header to provide the full path name of the file.
+func FileInfoHeader(fi os.FileInfo, link string) (*Header, error) {
+	if fi == nil {
+		return nil, errors.New("tar: FileInfo is nil")
+	}
+	fm := fi.Mode()
+	h := &Header{
+		Name:    fi.Name(),
+		ModTime: fi.ModTime(),
+		Mode:    int64(fm.Perm()), // or'd with c_IS* constants later
+	}
+	switch {
+	case fm.IsRegular():
+		h.Mode |= c_ISREG
+		h.Typeflag = TypeReg
+		h.Size = fi.Size()
+	case fi.IsDir():
+		h.Typeflag = TypeDir
+		h.Mode |= c_ISDIR
+		h.Name += "/"
+	case fm&os.ModeSymlink != 0:
+		h.Typeflag = TypeSymlink
+		h.Mode |= c_ISLNK
+		h.Linkname = link
+	case fm&os.ModeDevice != 0:
+		if fm&os.ModeCharDevice != 0 {
+			h.Mode |= c_ISCHR
+			h.Typeflag = TypeChar
+		} else {
+			h.Mode |= c_ISBLK
+			h.Typeflag = TypeBlock
+		}
+	case fm&os.ModeNamedPipe != 0:
+		h.Typeflag = TypeFifo
+		h.Mode |= c_ISFIFO
+	case fm&os.ModeSocket != 0:
+		h.Mode |= c_ISSOCK
+	default:
+		return nil, fmt.Errorf("archive/tar: unknown file mode %v", fm)
+	}
+	if fm&os.ModeSetuid != 0 {
+		h.Mode |= c_ISUID
+	}
+	if fm&os.ModeSetgid != 0 {
+		h.Mode |= c_ISGID
+	}
+	if fm&os.ModeSticky != 0 {
+		h.Mode |= c_ISVTX
+	}
+	if sysStat != nil {
+		return h, sysStat(fi, h)
+	}
+	return h, nil
+}
+
+var zeroBlock = make([]byte, blockSize)
+
+// POSIX specifies a sum of the unsigned byte values, but the Sun tar uses signed byte values.
+// We compute and return both.
+func checksum(header []byte) (unsigned int64, signed int64) {
+	for i := 0; i < len(header); i++ {
+		if i == 148 {
+			// The chksum field (header[148:156]) is special: it should be treated as space bytes.
+			unsigned += ' ' * 8
+			signed += ' ' * 8
+			i += 7
+			continue
+		}
+		unsigned += int64(header[i])
+		signed += int64(int8(header[i]))
+	}
+	return
+}
+
+type slicer []byte
+
+func (sp *slicer) next(n int) (b []byte) {
+	s := *sp
+	b, *sp = s[0:n], s[n:]
+	return
+}
+
+func isASCII(s string) bool {
+	for _, c := range s {
+		if c >= 0x80 {
+			return false
+		}
+	}
+	return true
+}
+
+func toASCII(s string) string {
+	if isASCII(s) {
+		return s
+	}
+	var buf bytes.Buffer
+	for _, c := range s {
+		if c < 0x80 {
+			buf.WriteByte(byte(c))
+		}
+	}
+	return buf.String()
+}

vendor/src/github.com/vbatts/tar-split/archive/tar/example_test.go

@@ -0,0 +1,80 @@
+// Copyright 2013 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package tar_test
+
+import (
+	"archive/tar"
+	"bytes"
+	"fmt"
+	"io"
+	"log"
+	"os"
+)
+
+func Example() {
+	// Create a buffer to write our archive to.
+	buf := new(bytes.Buffer)
+
+	// Create a new tar archive.
+	tw := tar.NewWriter(buf)
+
+	// Add some files to the archive.
+	var files = []struct {
+		Name, Body string
+	}{
+		{"readme.txt", "This archive contains some text files."},
+		{"gopher.txt", "Gopher names:\nGeorge\nGeoffrey\nGonzo"},
+		{"todo.txt", "Get animal handling licence."},
+	}
+	for _, file := range files {
+		hdr := &tar.Header{
+			Name: file.Name,
+			Mode: 0600,
+			Size: int64(len(file.Body)),
+		}
+		if err := tw.WriteHeader(hdr); err != nil {
+			log.Fatalln(err)
+		}
+		if _, err := tw.Write([]byte(file.Body)); err != nil {
+			log.Fatalln(err)
+		}
+	}
+	// Make sure to check the error on Close.
+	if err := tw.Close(); err != nil {
+		log.Fatalln(err)
+	}
+
+	// Open the tar archive for reading.
+	r := bytes.NewReader(buf.Bytes())
+	tr := tar.NewReader(r)
+
+	// Iterate through the files in the archive.
+	for {
+		hdr, err := tr.Next()
+		if err == io.EOF {
+			// end of tar archive
+			break
+		}
+		if err != nil {
+			log.Fatalln(err)
+		}
+		fmt.Printf("Contents of %s:\n", hdr.Name)
+		if _, err := io.Copy(os.Stdout, tr); err != nil {
+			log.Fatalln(err)
+		}
+		fmt.Println()
+	}
+
+	// Output:
+	// Contents of readme.txt:
+	// This archive contains some text files.
+	// Contents of gopher.txt:
+	// Gopher names:
+	// George
+	// Geoffrey
+	// Gonzo
+	// Contents of todo.txt:
+	// Get animal handling licence.
+}

vendor/src/github.com/vbatts/tar-split/archive/tar/reader.go

@@ -0,0 +1,926 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package tar
+
+// TODO(dsymonds):
+//   - pax extensions
+
+import (
+	"bytes"
+	"errors"
+	"io"
+	"io/ioutil"
+	"os"
+	"strconv"
+	"strings"
+	"time"
+)
+
+var (
+	ErrHeader = errors.New("archive/tar: invalid tar header")
+)
+
+const maxNanoSecondIntSize = 9
+
+// A Reader provides sequential access to the contents of a tar archive.
+// A tar archive consists of a sequence of files.
+// The Next method advances to the next file in the archive (including the first),
+// and then it can be treated as an io.Reader to access the file's data.
+type Reader struct {
+	r       io.Reader
+	err     error
+	pad     int64           // amount of padding (ignored) after current file entry
+	curr    numBytesReader  // reader for current file entry
+	hdrBuff [blockSize]byte // buffer to use in readHeader
+
+	RawAccounting bool          // Whether to enable the access needed to reassemble the tar from raw bytes. Some performance/memory hit for this.
+	rawBytes      *bytes.Buffer // last raw bits
+}
+
+// RawBytes accesses the raw bytes of the archive, apart from the file payload itself.
+// This includes the header and padding.
+//
+// This call resets the current rawbytes buffer
+//
+// Only when RawAccounting is enabled, otherwise this returns nil
+func (tr *Reader) RawBytes() []byte {
+	if !tr.RawAccounting {
+		return nil
+	}
+	if tr.rawBytes == nil {
+		tr.rawBytes = bytes.NewBuffer(nil)
+	}
+	// if we've read them, then flush them.
+	defer tr.rawBytes.Reset()
+	return tr.rawBytes.Bytes()
+}
+
+// A numBytesReader is an io.Reader with a numBytes method, returning the number
+// of bytes remaining in the underlying encoded data.
+type numBytesReader interface {
+	io.Reader
+	numBytes() int64
+}
+
+// A regFileReader is a numBytesReader for reading file data from a tar archive.
+type regFileReader struct {
+	r  io.Reader // underlying reader
+	nb int64     // number of unread bytes for current file entry
+}
+
+// A sparseFileReader is a numBytesReader for reading sparse file data from a tar archive.
+type sparseFileReader struct {
+	rfr *regFileReader // reads the sparse-encoded file data
+	sp  []sparseEntry  // the sparse map for the file
+	pos int64          // keeps track of file position
+	tot int64          // total size of the file
+}
+
+// Keywords for GNU sparse files in a PAX extended header
+const (
+	paxGNUSparseNumBlocks = "GNU.sparse.numblocks"
+	paxGNUSparseOffset    = "GNU.sparse.offset"
+	paxGNUSparseNumBytes  = "GNU.sparse.numbytes"
+	paxGNUSparseMap       = "GNU.sparse.map"
+	paxGNUSparseName      = "GNU.sparse.name"
+	paxGNUSparseMajor     = "GNU.sparse.major"
+	paxGNUSparseMinor     = "GNU.sparse.minor"
+	paxGNUSparseSize      = "GNU.sparse.size"
+	paxGNUSparseRealSize  = "GNU.sparse.realsize"
+)
+
+// Keywords for old GNU sparse headers
+const (
+	oldGNUSparseMainHeaderOffset               = 386
+	oldGNUSparseMainHeaderIsExtendedOffset     = 482
+	oldGNUSparseMainHeaderNumEntries           = 4
+	oldGNUSparseExtendedHeaderIsExtendedOffset = 504
+	oldGNUSparseExtendedHeaderNumEntries       = 21
+	oldGNUSparseOffsetSize                     = 12
+	oldGNUSparseNumBytesSize                   = 12
+)
+
+// NewReader creates a new Reader reading from r.
+func NewReader(r io.Reader) *Reader { return &Reader{r: r} }
+
+// Next advances to the next entry in the tar archive.
+//
+// io.EOF is returned at the end of the input.
+func (tr *Reader) Next() (*Header, error) {
+	var hdr *Header
+	if tr.RawAccounting {
+		if tr.rawBytes == nil {
+			tr.rawBytes = bytes.NewBuffer(nil)
+		} else {
+			tr.rawBytes.Reset()
+		}
+	}
+	if tr.err == nil {
+		tr.skipUnread()
+	}
+	if tr.err != nil {
+		return hdr, tr.err
+	}
+	hdr = tr.readHeader()
+	if hdr == nil {
+		return hdr, tr.err
+	}
+	// Check for PAX/GNU header.
+	switch hdr.Typeflag {
+	case TypeXHeader:
+		//  PAX extended header
+		headers, err := parsePAX(tr)
+		if err != nil {
+			return nil, err
+		}
+		// We actually read the whole file,
+		// but this skips alignment padding
+		tr.skipUnread()
+		hdr = tr.readHeader()
+		mergePAX(hdr, headers)
+
+		// Check for a PAX format sparse file
+		sp, err := tr.checkForGNUSparsePAXHeaders(hdr, headers)
+		if err != nil {
+			tr.err = err
+			return nil, err
+		}
+		if sp != nil {
+			// Current file is a PAX format GNU sparse file.
+			// Set the current file reader to a sparse file reader.
+			tr.curr = &sparseFileReader{rfr: tr.curr.(*regFileReader), sp: sp, tot: hdr.Size}
+		}
+		return hdr, nil
+	case TypeGNULongName:
+		// We have a GNU long name header. Its contents are the real file name.
+		realname, err := ioutil.ReadAll(tr)
+		if err != nil {
+			return nil, err
+		}
+		var b []byte
+		if tr.RawAccounting {
+			if _, err = tr.rawBytes.Write(realname); err != nil {
+				return nil, err
+			}
+			b = tr.RawBytes()
+		}
+		hdr, err := tr.Next()
+		// since the above call to Next() resets the buffer, we need to throw the bytes over
+		if tr.RawAccounting {
+			if _, err = tr.rawBytes.Write(b); err != nil {
+				return nil, err
+			}
+		}
+		hdr.Name = cString(realname)
+		return hdr, err
+	case TypeGNULongLink:
+		// We have a GNU long link header.
+		realname, err := ioutil.ReadAll(tr)
+		if err != nil {
+			return nil, err
+		}
+		var b []byte
+		if tr.RawAccounting {
+			if _, err = tr.rawBytes.Write(realname); err != nil {
+				return nil, err
+			}
+			b = tr.RawBytes()
+		}
+		hdr, err := tr.Next()
+		// since the above call to Next() resets the buffer, we need to throw the bytes over
+		if tr.RawAccounting {
+			if _, err = tr.rawBytes.Write(b); err != nil {
+				return nil, err
+			}
+		}
+		hdr.Linkname = cString(realname)
+		return hdr, err
+	}
+	return hdr, tr.err
+}
+
+// checkForGNUSparsePAXHeaders checks the PAX headers for GNU sparse headers. If they are found, then
+// this function reads the sparse map and returns it. Unknown sparse formats are ignored, causing the file to
+// be treated as a regular file.
+func (tr *Reader) checkForGNUSparsePAXHeaders(hdr *Header, headers map[string]string) ([]sparseEntry, error) {
+	var sparseFormat string
+
+	// Check for sparse format indicators
+	major, majorOk := headers[paxGNUSparseMajor]
+	minor, minorOk := headers[paxGNUSparseMinor]
+	sparseName, sparseNameOk := headers[paxGNUSparseName]
+	_, sparseMapOk := headers[paxGNUSparseMap]
+	sparseSize, sparseSizeOk := headers[paxGNUSparseSize]
+	sparseRealSize, sparseRealSizeOk := headers[paxGNUSparseRealSize]
+
+	// Identify which, if any, sparse format applies from which PAX headers are set
+	if majorOk && minorOk {
+		sparseFormat = major + "." + minor
+	} else if sparseNameOk && sparseMapOk {
+		sparseFormat = "0.1"
+	} else if sparseSizeOk {
+		sparseFormat = "0.0"
+	} else {
+		// Not a PAX format GNU sparse file.
+		return nil, nil
+	}
+
+	// Check for unknown sparse format
+	if sparseFormat != "0.0" && sparseFormat != "0.1" && sparseFormat != "1.0" {
+		return nil, nil
+	}
+
+	// Update hdr from GNU sparse PAX headers
+	if sparseNameOk {
+		hdr.Name = sparseName
+	}
+	if sparseSizeOk {
+		realSize, err := strconv.ParseInt(sparseSize, 10, 0)
+		if err != nil {
+			return nil, ErrHeader
+		}
+		hdr.Size = realSize
+	} else if sparseRealSizeOk {
+		realSize, err := strconv.ParseInt(sparseRealSize, 10, 0)
+		if err != nil {
+			return nil, ErrHeader
+		}
+		hdr.Size = realSize
+	}
+
+	// Set up the sparse map, according to the particular sparse format in use
+	var sp []sparseEntry
+	var err error
+	switch sparseFormat {
+	case "0.0", "0.1":
+		sp, err = readGNUSparseMap0x1(headers)
+	case "1.0":
+		sp, err = readGNUSparseMap1x0(tr.curr)
+	}
+	return sp, err
+}
+
+// mergePAX merges well known headers according to PAX standard.
+// In general headers with the same name as those found
+// in the header struct overwrite those found in the header
+// struct with higher precision or longer values. Esp. useful
+// for name and linkname fields.
+func mergePAX(hdr *Header, headers map[string]string) error {
+	for k, v := range headers {
+		switch k {
+		case paxPath:
+			hdr.Name = v
+		case paxLinkpath:
+			hdr.Linkname = v
+		case paxGname:
+			hdr.Gname = v
+		case paxUname:
+			hdr.Uname = v
+		case paxUid:
+			uid, err := strconv.ParseInt(v, 10, 0)
+			if err != nil {
+				return err
+			}
+			hdr.Uid = int(uid)
+		case paxGid:
+			gid, err := strconv.ParseInt(v, 10, 0)
+			if err != nil {
+				return err
+			}
+			hdr.Gid = int(gid)
+		case paxAtime:
+			t, err := parsePAXTime(v)
+			if err != nil {
+				return err
+			}
+			hdr.AccessTime = t
+		case paxMtime:
+			t, err := parsePAXTime(v)
+			if err != nil {
+				return err
+			}
+			hdr.ModTime = t
+		case paxCtime:
+			t, err := parsePAXTime(v)
+			if err != nil {
+				return err
+			}
+			hdr.ChangeTime = t
+		case paxSize:
+			size, err := strconv.ParseInt(v, 10, 0)
+			if err != nil {
+				return err
+			}
+			hdr.Size = int64(size)
+		default:
+			if strings.HasPrefix(k, paxXattr) {
+				if hdr.Xattrs == nil {
+					hdr.Xattrs = make(map[string]string)
+				}
+				hdr.Xattrs[k[len(paxXattr):]] = v
+			}
+		}
+	}
+	return nil
+}
+
+// parsePAXTime takes a string of the form %d.%d as described in
+// the PAX specification.
+func parsePAXTime(t string) (time.Time, error) {
+	buf := []byte(t)
+	pos := bytes.IndexByte(buf, '.')
+	var seconds, nanoseconds int64
+	var err error
+	if pos == -1 {
+		seconds, err = strconv.ParseInt(t, 10, 0)
+		if err != nil {
+			return time.Time{}, err
+		}
+	} else {
+		seconds, err = strconv.ParseInt(string(buf[:pos]), 10, 0)
+		if err != nil {
+			return time.Time{}, err
+		}
+		nano_buf := string(buf[pos+1:])
+		// Pad as needed before converting to a decimal.
+		// For example .030 -> .030000000 -> 30000000 nanoseconds
+		if len(nano_buf) < maxNanoSecondIntSize {
+			// Right pad
+			nano_buf += strings.Repeat("0", maxNanoSecondIntSize-len(nano_buf))
+		} else if len(nano_buf) > maxNanoSecondIntSize {
+			// Right truncate
+			nano_buf = nano_buf[:maxNanoSecondIntSize]
+		}
+		nanoseconds, err = strconv.ParseInt(string(nano_buf), 10, 0)
+		if err != nil {
+			return time.Time{}, err
+		}
+	}
+	ts := time.Unix(seconds, nanoseconds)
+	return ts, nil
+}
+
+// parsePAX parses PAX headers.
+// If an extended header (type 'x') is invalid, ErrHeader is returned
+func parsePAX(r io.Reader) (map[string]string, error) {
+	buf, err := ioutil.ReadAll(r)
+	if err != nil {
+		return nil, err
+	}
+	// leaving this function for io.Reader makes it more testable
+	if tr, ok := r.(*Reader); ok && tr.RawAccounting {
+		if _, err = tr.rawBytes.Write(buf); err != nil {
+			return nil, err
+		}
+	}
+
+	// For GNU PAX sparse format 0.0 support.
+	// This function transforms the sparse format 0.0 headers into sparse format 0.1 headers.
+	var sparseMap bytes.Buffer
+
+	headers := make(map[string]string)
+	// Each record is constructed as
+	//     "%d %s=%s\n", length, keyword, value
+	for len(buf) > 0 {
+		// or the header was empty to start with.
+		var sp int
+		// The size field ends at the first space.
+		sp = bytes.IndexByte(buf, ' ')
+		if sp == -1 {
+			return nil, ErrHeader
+		}
+		// Parse the first token as a decimal integer.
+		n, err := strconv.ParseInt(string(buf[:sp]), 10, 0)
+		if err != nil {
+			return nil, ErrHeader
+		}
+		// Extract everything between the decimal and the n -1 on the
+		// beginning to eat the ' ', -1 on the end to skip the newline.
+		var record []byte
+		record, buf = buf[sp+1:n-1], buf[n:]
+		// The first equals is guaranteed to mark the end of the key.
+		// Everything else is value.
+		eq := bytes.IndexByte(record, '=')
+		if eq == -1 {
+			return nil, ErrHeader
+		}
+		key, value := record[:eq], record[eq+1:]
+
+		keyStr := string(key)
+		if keyStr == paxGNUSparseOffset || keyStr == paxGNUSparseNumBytes {
+			// GNU sparse format 0.0 special key. Write to sparseMap instead of using the headers map.
+			sparseMap.Write(value)
+			sparseMap.Write([]byte{','})
+		} else {
+			// Normal key. Set the value in the headers map.
+			headers[keyStr] = string(value)
+		}
+	}
+	if sparseMap.Len() != 0 {
+		// Add sparse info to headers, chopping off the extra comma
+		sparseMap.Truncate(sparseMap.Len() - 1)
+		headers[paxGNUSparseMap] = sparseMap.String()
+	}
+	return headers, nil
+}
+
+// cString parses bytes as a NUL-terminated C-style string.
+// If a NUL byte is not found then the whole slice is returned as a string.
+func cString(b []byte) string {
+	n := 0
+	for n < len(b) && b[n] != 0 {
+		n++
+	}
+	return string(b[0:n])
+}
+
+func (tr *Reader) octal(b []byte) int64 {
+	// Check for binary format first.
+	if len(b) > 0 && b[0]&0x80 != 0 {
+		var x int64
+		for i, c := range b {
+			if i == 0 {
+				c &= 0x7f // ignore signal bit in first byte
+			}
+			x = x<<8 | int64(c)
+		}
+		return x
+	}
+
+	// Because unused fields are filled with NULs, we need
+	// to skip leading NULs. Fields may also be padded with
+	// spaces or NULs.
+	// So we remove leading and trailing NULs and spaces to
+	// be sure.
+	b = bytes.Trim(b, " \x00")
+
+	if len(b) == 0 {
+		return 0
+	}
+	x, err := strconv.ParseUint(cString(b), 8, 64)
+	if err != nil {
+		tr.err = err
+	}
+	return int64(x)
+}
+
+// skipUnread skips any unread bytes in the existing file entry, as well as any alignment padding.
+func (tr *Reader) skipUnread() {
+	nr := tr.numBytes() + tr.pad // number of bytes to skip
+	tr.curr, tr.pad = nil, 0
+	if tr.RawAccounting {
+		_, tr.err = io.CopyN(tr.rawBytes, tr.r, nr)
+		return
+	}
+	if sr, ok := tr.r.(io.Seeker); ok {
+		if _, err := sr.Seek(nr, os.SEEK_CUR); err == nil {
+			return
+		}
+	}
+	_, tr.err = io.CopyN(ioutil.Discard, tr.r, nr)
+}
+
+func (tr *Reader) verifyChecksum(header []byte) bool {
+	if tr.err != nil {
+		return false
+	}
+
+	given := tr.octal(header[148:156])
+	unsigned, signed := checksum(header)
+	return given == unsigned || given == signed
+}
+
+func (tr *Reader) readHeader() *Header {
+	header := tr.hdrBuff[:]
+	copy(header, zeroBlock)
+
+	if _, tr.err = io.ReadFull(tr.r, header); tr.err != nil {
+		// because it could read some of the block, but reach EOF first
+		if tr.err == io.EOF && tr.RawAccounting {
+			if _, tr.err = tr.rawBytes.Write(header); tr.err != nil {
+				return nil
+			}
+		}
+		return nil
+	}
+	if tr.RawAccounting {
+		if _, tr.err = tr.rawBytes.Write(header); tr.err != nil {
+			return nil
+		}
+	}
+
+	// Two blocks of zero bytes marks the end of the archive.
+	if bytes.Equal(header, zeroBlock[0:blockSize]) {
+		if _, tr.err = io.ReadFull(tr.r, header); tr.err != nil {
+			// because it could read some of the block, but reach EOF first
+			if tr.err == io.EOF && tr.RawAccounting {
+				if _, tr.err = tr.rawBytes.Write(header); tr.err != nil {
+					return nil
+				}
+			}
+			return nil
+		}
+		if tr.RawAccounting {
+			if _, tr.err = tr.rawBytes.Write(header); tr.err != nil {
+				return nil
+			}
+		}
+		if bytes.Equal(header, zeroBlock[0:blockSize]) {
+			tr.err = io.EOF
+		} else {
+			tr.err = ErrHeader // zero block and then non-zero block
+		}
+		return nil
+	}
+
+	if !tr.verifyChecksum(header) {
+		tr.err = ErrHeader
+		return nil
+	}
+
+	// Unpack
+	hdr := new(Header)
+	s := slicer(header)
+
+	hdr.Name = cString(s.next(100))
+	hdr.Mode = tr.octal(s.next(8))
+	hdr.Uid = int(tr.octal(s.next(8)))
+	hdr.Gid = int(tr.octal(s.next(8)))
+	hdr.Size = tr.octal(s.next(12))
+	hdr.ModTime = time.Unix(tr.octal(s.next(12)), 0)
+	s.next(8) // chksum
+	hdr.Typeflag = s.next(1)[0]
+	hdr.Linkname = cString(s.next(100))
+
+	// The remainder of the header depends on the value of magic.
+	// The original (v7) version of tar had no explicit magic field,
+	// so its magic bytes, like the rest of the block, are NULs.
+	magic := string(s.next(8)) // contains version field as well.
+	var format string
+	switch {
+	case magic[:6] == "ustar\x00": // POSIX tar (1003.1-1988)
+		if string(header[508:512]) == "tar\x00" {
+			format = "star"
+		} else {
+			format = "posix"
+		}
+	case magic == "ustar  \x00": // old GNU tar
+		format = "gnu"
+	}
+
+	switch format {
+	case "posix", "gnu", "star":
+		hdr.Uname = cString(s.next(32))
+		hdr.Gname = cString(s.next(32))
+		devmajor := s.next(8)
+		devminor := s.next(8)
+		if hdr.Typeflag == TypeChar || hdr.Typeflag == TypeBlock {
+			hdr.Devmajor = tr.octal(devmajor)
+			hdr.Devminor = tr.octal(devminor)
+		}
+		var prefix string
+		switch format {
+		case "posix", "gnu":
+			prefix = cString(s.next(155))
+		case "star":
+			prefix = cString(s.next(131))
+			hdr.AccessTime = time.Unix(tr.octal(s.next(12)), 0)
+			hdr.ChangeTime = time.Unix(tr.octal(s.next(12)), 0)
+		}
+		if len(prefix) > 0 {
+			hdr.Name = prefix + "/" + hdr.Name
+		}
+	}
+
+	if tr.err != nil {
+		tr.err = ErrHeader
+		return nil
+	}
+
+	// Maximum value of hdr.Size is 64 GB (12 octal digits),
+	// so there's no risk of int64 overflowing.
+	nb := int64(hdr.Size)
+	tr.pad = -nb & (blockSize - 1) // blockSize is a power of two
+
+	// Set the current file reader.
+	tr.curr = &regFileReader{r: tr.r, nb: nb}
+
+	// Check for old GNU sparse format entry.
+	if hdr.Typeflag == TypeGNUSparse {
+		// Get the real size of the file.
+		hdr.Size = tr.octal(header[483:495])
+
+		// Read the sparse map.
+		sp := tr.readOldGNUSparseMap(header)
+		if tr.err != nil {
+			return nil
+		}
+		// Current file is a GNU sparse file. Update the current file reader.
+		tr.curr = &sparseFileReader{rfr: tr.curr.(*regFileReader), sp: sp, tot: hdr.Size}
+	}
+
+	return hdr
+}
+
+// A sparseEntry holds a single entry in a sparse file's sparse map.
+// A sparse entry indicates the offset and size in a sparse file of a
+// block of data.
+type sparseEntry struct {
+	offset   int64
+	numBytes int64
+}
+
+// readOldGNUSparseMap reads the sparse map as stored in the old GNU sparse format.
+// The sparse map is stored in the tar header if it's small enough. If it's larger than four entries,
+// then one or more extension headers are used to store the rest of the sparse map.
+func (tr *Reader) readOldGNUSparseMap(header []byte) []sparseEntry {
+	isExtended := header[oldGNUSparseMainHeaderIsExtendedOffset] != 0
+	spCap := oldGNUSparseMainHeaderNumEntries
+	if isExtended {
+		spCap += oldGNUSparseExtendedHeaderNumEntries
+	}
+	sp := make([]sparseEntry, 0, spCap)
+	s := slicer(header[oldGNUSparseMainHeaderOffset:])
+
+	// Read the four entries from the main tar header
+	for i := 0; i < oldGNUSparseMainHeaderNumEntries; i++ {
+		offset := tr.octal(s.next(oldGNUSparseOffsetSize))
+		numBytes := tr.octal(s.next(oldGNUSparseNumBytesSize))
+		if tr.err != nil {
+			tr.err = ErrHeader
+			return nil
+		}
+		if offset == 0 && numBytes == 0 {
+			break
+		}
+		sp = append(sp, sparseEntry{offset: offset, numBytes: numBytes})
+	}
+
+	for isExtended {
+		// There are more entries. Read an extension header and parse its entries.
+		sparseHeader := make([]byte, blockSize)
+		if _, tr.err = io.ReadFull(tr.r, sparseHeader); tr.err != nil {
+			return nil
+		}
+		if tr.RawAccounting {
+			if _, tr.err = tr.rawBytes.Write(sparseHeader); tr.err != nil {
+				return nil
+			}
+		}
+
+		isExtended = sparseHeader[oldGNUSparseExtendedHeaderIsExtendedOffset] != 0
+		s = slicer(sparseHeader)
+		for i := 0; i < oldGNUSparseExtendedHeaderNumEntries; i++ {
+			offset := tr.octal(s.next(oldGNUSparseOffsetSize))
+			numBytes := tr.octal(s.next(oldGNUSparseNumBytesSize))
+			if tr.err != nil {
+				tr.err = ErrHeader
+				return nil
+			}
+			if offset == 0 && numBytes == 0 {
+				break
+			}
+			sp = append(sp, sparseEntry{offset: offset, numBytes: numBytes})
+		}
+	}
+	return sp
+}
+
+// readGNUSparseMap1x0 reads the sparse map as stored in GNU's PAX sparse format version 1.0.
+// The sparse map is stored just before the file data and padded out to the nearest block boundary.
+func readGNUSparseMap1x0(r io.Reader) ([]sparseEntry, error) {
+	buf := make([]byte, 2*blockSize)
+	sparseHeader := buf[:blockSize]
+
+	// readDecimal is a helper function to read a decimal integer from the sparse map
+	// while making sure to read from the file in blocks of size blockSize
+	readDecimal := func() (int64, error) {
+		// Look for newline
+		nl := bytes.IndexByte(sparseHeader, '\n')
+		if nl == -1 {
+			if len(sparseHeader) >= blockSize {
+				// This is an error
+				return 0, ErrHeader
+			}
+			oldLen := len(sparseHeader)
+			newLen := oldLen + blockSize
+			if cap(sparseHeader) < newLen {
+				// There's more header, but we need to make room for the next block
+				copy(buf, sparseHeader)
+				sparseHeader = buf[:newLen]
+			} else {
+				// There's more header, and we can just reslice
+				sparseHeader = sparseHeader[:newLen]
+			}
+
+			// Now that sparseHeader is large enough, read next block
+			if _, err := io.ReadFull(r, sparseHeader[oldLen:newLen]); err != nil {
+				return 0, err
+			}
+			// leaving this function for io.Reader makes it more testable
+			if tr, ok := r.(*Reader); ok && tr.RawAccounting {
+				if _, err := tr.rawBytes.Write(sparseHeader[oldLen:newLen]); err != nil {
+					return 0, err
+				}
+			}
+
+			// Look for a newline in the new data
+			nl = bytes.IndexByte(sparseHeader[oldLen:newLen], '\n')
+			if nl == -1 {
+				// This is an error
+				return 0, ErrHeader
+			}
+			nl += oldLen // We want the position from the beginning
+		}
+		// Now that we've found a newline, read a number
+		n, err := strconv.ParseInt(string(sparseHeader[:nl]), 10, 0)
+		if err != nil {
+			return 0, ErrHeader
+		}
+
+		// Update sparseHeader to consume this number
+		sparseHeader = sparseHeader[nl+1:]
+		return n, nil
+	}
+
+	// Read the first block
+	if _, err := io.ReadFull(r, sparseHeader); err != nil {
+		return nil, err
+	}
+	// leaving this function for io.Reader makes it more testable
+	if tr, ok := r.(*Reader); ok && tr.RawAccounting {
+		if _, err := tr.rawBytes.Write(sparseHeader); err != nil {
+			return nil, err
+		}
+	}
+
+	// The first line contains the number of entries
+	numEntries, err := readDecimal()
+	if err != nil {
+		return nil, err
+	}
+
+	// Read all the entries
+	sp := make([]sparseEntry, 0, numEntries)
+	for i := int64(0); i < numEntries; i++ {
+		// Read the offset
+		offset, err := readDecimal()
+		if err != nil {
+			return nil, err
+		}
+		// Read numBytes
+		numBytes, err := readDecimal()
+		if err != nil {
+			return nil, err
+		}
+
+		sp = append(sp, sparseEntry{offset: offset, numBytes: numBytes})
+	}
+
+	return sp, nil
+}
+
+// readGNUSparseMap0x1 reads the sparse map as stored in GNU's PAX sparse format version 0.1.
+// The sparse map is stored in the PAX headers.
+func readGNUSparseMap0x1(headers map[string]string) ([]sparseEntry, error) {
+	// Get number of entries
+	numEntriesStr, ok := headers[paxGNUSparseNumBlocks]
+	if !ok {
+		return nil, ErrHeader
+	}
+	numEntries, err := strconv.ParseInt(numEntriesStr, 10, 0)
+	if err != nil {
+		return nil, ErrHeader
+	}
+
+	sparseMap := strings.Split(headers[paxGNUSparseMap], ",")
+
+	// There should be two numbers in sparseMap for each entry
+	if int64(len(sparseMap)) != 2*numEntries {
+		return nil, ErrHeader
+	}
+
+	// Loop through the entries in the sparse map
+	sp := make([]sparseEntry, 0, numEntries)
+	for i := int64(0); i < numEntries; i++ {
+		offset, err := strconv.ParseInt(sparseMap[2*i], 10, 0)
+		if err != nil {
+			return nil, ErrHeader
+		}
+		numBytes, err := strconv.ParseInt(sparseMap[2*i+1], 10, 0)
+		if err != nil {
+			return nil, ErrHeader
+		}
+		sp = append(sp, sparseEntry{offset: offset, numBytes: numBytes})
+	}
+
+	return sp, nil
+}
+
+// numBytes returns the number of bytes left to read in the current file's entry
+// in the tar archive, or 0 if there is no current file.
+func (tr *Reader) numBytes() int64 {
+	if tr.curr == nil {
+		// No current file, so no bytes
+		return 0
+	}
+	return tr.curr.numBytes()
+}
+
+// Read reads from the current entry in the tar archive.
+// It returns 0, io.EOF when it reaches the end of that entry,
+// until Next is called to advance to the next entry.
+func (tr *Reader) Read(b []byte) (n int, err error) {
+	if tr.curr == nil {
+		return 0, io.EOF
+	}
+	n, err = tr.curr.Read(b)
+	if err != nil && err != io.EOF {
+		tr.err = err
+	}
+	return
+}
+
+func (rfr *regFileReader) Read(b []byte) (n int, err error) {
+	if rfr.nb == 0 {
+		// file consumed
+		return 0, io.EOF
+	}
+	if int64(len(b)) > rfr.nb {
+		b = b[0:rfr.nb]
+	}
+	n, err = rfr.r.Read(b)
+	rfr.nb -= int64(n)
+
+	if err == io.EOF && rfr.nb > 0 {
+		err = io.ErrUnexpectedEOF
+	}
+	return
+}
+
+// numBytes returns the number of bytes left to read in the file's data in the tar archive.
+func (rfr *regFileReader) numBytes() int64 {
+	return rfr.nb
+}
+
+// readHole reads a sparse file hole ending at offset toOffset
+func (sfr *sparseFileReader) readHole(b []byte, toOffset int64) int {
+	n64 := toOffset - sfr.pos
+	if n64 > int64(len(b)) {
+		n64 = int64(len(b))
+	}
+	n := int(n64)
+	for i := 0; i < n; i++ {
+		b[i] = 0
+	}
+	sfr.pos += n64
+	return n
+}
+
+// Read reads the sparse file data in expanded form.
+func (sfr *sparseFileReader) Read(b []byte) (n int, err error) {
+	if len(sfr.sp) == 0 {
+		// No more data fragments to read from.
+		if sfr.pos < sfr.tot {
+			// We're in the last hole
+			n = sfr.readHole(b, sfr.tot)
+			return
+		}
+		// Otherwise, we're at the end of the file
+		return 0, io.EOF
+	}
+	if sfr.pos < sfr.sp[0].offset {
+		// We're in a hole
+		n = sfr.readHole(b, sfr.sp[0].offset)
+		return
+	}
+
+	// We're not in a hole, so we'll read from the next data fragment
+	posInFragment := sfr.pos - sfr.sp[0].offset
+	bytesLeft := sfr.sp[0].numBytes - posInFragment
+	if int64(len(b)) > bytesLeft {
+		b = b[0:bytesLeft]
+	}
+
+	n, err = sfr.rfr.Read(b)
+	sfr.pos += int64(n)
+
+	if int64(n) == bytesLeft {
+		// We're done with this fragment
+		sfr.sp = sfr.sp[1:]
+	}
+
+	if err == io.EOF && sfr.pos < sfr.tot {
+		// We reached the end of the last fragment's data, but there's a final hole
+		err = nil
+	}
+	return
+}
+
+// numBytes returns the number of bytes left to read in the sparse file's
+// sparse-encoded data in the tar archive.
+func (sfr *sparseFileReader) numBytes() int64 {
+	return sfr.rfr.nb
+}

vendor/src/github.com/vbatts/tar-split/archive/tar/reader_test.go

@@ -0,0 +1,743 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package tar
+
+import (
+	"bytes"
+	"crypto/md5"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"os"
+	"reflect"
+	"strings"
+	"testing"
+	"time"
+)
+
+type untarTest struct {
+	file    string
+	headers []*Header
+	cksums  []string
+}
+
+var gnuTarTest = &untarTest{
+	file: "testdata/gnu.tar",
+	headers: []*Header{
+		{
+			Name:     "small.txt",
+			Mode:     0640,
+			Uid:      73025,
+			Gid:      5000,
+			Size:     5,
+			ModTime:  time.Unix(1244428340, 0),
+			Typeflag: '0',
+			Uname:    "dsymonds",
+			Gname:    "eng",
+		},
+		{
+			Name:     "small2.txt",
+			Mode:     0640,
+			Uid:      73025,
+			Gid:      5000,
+			Size:     11,
+			ModTime:  time.Unix(1244436044, 0),
+			Typeflag: '0',
+			Uname:    "dsymonds",
+			Gname:    "eng",
+		},
+	},
+	cksums: []string{
+		"e38b27eaccb4391bdec553a7f3ae6b2f",
+		"c65bd2e50a56a2138bf1716f2fd56fe9",
+	},
+}
+
+var sparseTarTest = &untarTest{
+	file: "testdata/sparse-formats.tar",
+	headers: []*Header{
+		{
+			Name:     "sparse-gnu",
+			Mode:     420,
+			Uid:      1000,
+			Gid:      1000,
+			Size:     200,
+			ModTime:  time.Unix(1392395740, 0),
+			Typeflag: 0x53,
+			Linkname: "",
+			Uname:    "david",
+			Gname:    "david",
+			Devmajor: 0,
+			Devminor: 0,
+		},
+		{
+			Name:     "sparse-posix-0.0",
+			Mode:     420,
+			Uid:      1000,
+			Gid:      1000,
+			Size:     200,
+			ModTime:  time.Unix(1392342187, 0),
+			Typeflag: 0x30,
+			Linkname: "",
+			Uname:    "david",
+			Gname:    "david",
+			Devmajor: 0,
+			Devminor: 0,
+		},
+		{
+			Name:     "sparse-posix-0.1",
+			Mode:     420,
+			Uid:      1000,
+			Gid:      1000,
+			Size:     200,
+			ModTime:  time.Unix(1392340456, 0),
+			Typeflag: 0x30,
+			Linkname: "",
+			Uname:    "david",
+			Gname:    "david",
+			Devmajor: 0,
+			Devminor: 0,
+		},
+		{
+			Name:     "sparse-posix-1.0",
+			Mode:     420,
+			Uid:      1000,
+			Gid:      1000,
+			Size:     200,
+			ModTime:  time.Unix(1392337404, 0),
+			Typeflag: 0x30,
+			Linkname: "",
+			Uname:    "david",
+			Gname:    "david",
+			Devmajor: 0,
+			Devminor: 0,
+		},
+		{
+			Name:     "end",
+			Mode:     420,
+			Uid:      1000,
+			Gid:      1000,
+			Size:     4,
+			ModTime:  time.Unix(1392398319, 0),
+			Typeflag: 0x30,
+			Linkname: "",
+			Uname:    "david",
+			Gname:    "david",
+			Devmajor: 0,
+			Devminor: 0,
+		},
+	},
+	cksums: []string{
+		"6f53234398c2449fe67c1812d993012f",
+		"6f53234398c2449fe67c1812d993012f",
+		"6f53234398c2449fe67c1812d993012f",
+		"6f53234398c2449fe67c1812d993012f",
+		"b0061974914468de549a2af8ced10316",
+	},
+}
+
+var untarTests = []*untarTest{
+	gnuTarTest,
+	sparseTarTest,
+	{
+		file: "testdata/star.tar",
+		headers: []*Header{
+			{
+				Name:       "small.txt",
+				Mode:       0640,
+				Uid:        73025,
+				Gid:        5000,
+				Size:       5,
+				ModTime:    time.Unix(1244592783, 0),
+				Typeflag:   '0',
+				Uname:      "dsymonds",
+				Gname:      "eng",
+				AccessTime: time.Unix(1244592783, 0),
+				ChangeTime: time.Unix(1244592783, 0),
+			},
+			{
+				Name:       "small2.txt",
+				Mode:       0640,
+				Uid:        73025,
+				Gid:        5000,
+				Size:       11,
+				ModTime:    time.Unix(1244592783, 0),
+				Typeflag:   '0',
+				Uname:      "dsymonds",
+				Gname:      "eng",
+				AccessTime: time.Unix(1244592783, 0),
+				ChangeTime: time.Unix(1244592783, 0),
+			},
+		},
+	},
+	{
+		file: "testdata/v7.tar",
+		headers: []*Header{
+			{
+				Name:     "small.txt",
+				Mode:     0444,
+				Uid:      73025,
+				Gid:      5000,
+				Size:     5,
+				ModTime:  time.Unix(1244593104, 0),
+				Typeflag: '\x00',
+			},
+			{
+				Name:     "small2.txt",
+				Mode:     0444,
+				Uid:      73025,
+				Gid:      5000,
+				Size:     11,
+				ModTime:  time.Unix(1244593104, 0),
+				Typeflag: '\x00',
+			},
+		},
+	},
+	{
+		file: "testdata/pax.tar",
+		headers: []*Header{
+			{
+				Name:       "a/123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100",
+				Mode:       0664,
+				Uid:        1000,
+				Gid:        1000,
+				Uname:      "shane",
+				Gname:      "shane",
+				Size:       7,
+				ModTime:    time.Unix(1350244992, 23960108),
+				ChangeTime: time.Unix(1350244992, 23960108),
+				AccessTime: time.Unix(1350244992, 23960108),
+				Typeflag:   TypeReg,
+			},
+			{
+				Name:       "a/b",
+				Mode:       0777,
+				Uid:        1000,
+				Gid:        1000,
+				Uname:      "shane",
+				Gname:      "shane",
+				Size:       0,
+				ModTime:    time.Unix(1350266320, 910238425),
+				ChangeTime: time.Unix(1350266320, 910238425),
+				AccessTime: time.Unix(1350266320, 910238425),
+				Typeflag:   TypeSymlink,
+				Linkname:   "123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100",
+			},
+		},
+	},
+	{
+		file: "testdata/nil-uid.tar", // golang.org/issue/5290
+		headers: []*Header{
+			{
+				Name:     "P1050238.JPG.log",
+				Mode:     0664,
+				Uid:      0,
+				Gid:      0,
+				Size:     14,
+				ModTime:  time.Unix(1365454838, 0),
+				Typeflag: TypeReg,
+				Linkname: "",
+				Uname:    "eyefi",
+				Gname:    "eyefi",
+				Devmajor: 0,
+				Devminor: 0,
+			},
+		},
+	},
+	{
+		file: "testdata/xattrs.tar",
+		headers: []*Header{
+			{
+				Name:       "small.txt",
+				Mode:       0644,
+				Uid:        1000,
+				Gid:        10,
+				Size:       5,
+				ModTime:    time.Unix(1386065770, 448252320),
+				Typeflag:   '0',
+				Uname:      "alex",
+				Gname:      "wheel",
+				AccessTime: time.Unix(1389782991, 419875220),
+				ChangeTime: time.Unix(1389782956, 794414986),
+				Xattrs: map[string]string{
+					"user.key":  "value",
+					"user.key2": "value2",
+					// Interestingly, selinux encodes the terminating null inside the xattr
+					"security.selinux": "unconfined_u:object_r:default_t:s0\x00",
+				},
+			},
+			{
+				Name:       "small2.txt",
+				Mode:       0644,
+				Uid:        1000,
+				Gid:        10,
+				Size:       11,
+				ModTime:    time.Unix(1386065770, 449252304),
+				Typeflag:   '0',
+				Uname:      "alex",
+				Gname:      "wheel",
+				AccessTime: time.Unix(1389782991, 419875220),
+				ChangeTime: time.Unix(1386065770, 449252304),
+				Xattrs: map[string]string{
+					"security.selinux": "unconfined_u:object_r:default_t:s0\x00",
+				},
+			},
+		},
+	},
+}
+
+func TestReader(t *testing.T) {
+testLoop:
+	for i, test := range untarTests {
+		f, err := os.Open(test.file)
+		if err != nil {
+			t.Errorf("test %d: Unexpected error: %v", i, err)
+			continue
+		}
+		defer f.Close()
+		tr := NewReader(f)
+		for j, header := range test.headers {
+			hdr, err := tr.Next()
+			if err != nil || hdr == nil {
+				t.Errorf("test %d, entry %d: Didn't get entry: %v", i, j, err)
+				f.Close()
+				continue testLoop
+			}
+			if !reflect.DeepEqual(*hdr, *header) {
+				t.Errorf("test %d, entry %d: Incorrect header:\nhave %+v\nwant %+v",
+					i, j, *hdr, *header)
+			}
+		}
+		hdr, err := tr.Next()
+		if err == io.EOF {
+			continue testLoop
+		}
+		if hdr != nil || err != nil {
+			t.Errorf("test %d: Unexpected entry or error: hdr=%v err=%v", i, hdr, err)
+		}
+	}
+}
+
+func TestPartialRead(t *testing.T) {
+	f, err := os.Open("testdata/gnu.tar")
+	if err != nil {
+		t.Fatalf("Unexpected error: %v", err)
+	}
+	defer f.Close()
+
+	tr := NewReader(f)
+
+	// Read the first four bytes; Next() should skip the last byte.
+	hdr, err := tr.Next()
+	if err != nil || hdr == nil {
+		t.Fatalf("Didn't get first file: %v", err)
+	}
+	buf := make([]byte, 4)
+	if _, err := io.ReadFull(tr, buf); err != nil {
+		t.Fatalf("Unexpected error: %v", err)
+	}
+	if expected := []byte("Kilt"); !bytes.Equal(buf, expected) {
+		t.Errorf("Contents = %v, want %v", buf, expected)
+	}
+
+	// Second file
+	hdr, err = tr.Next()
+	if err != nil || hdr == nil {
+		t.Fatalf("Didn't get second file: %v", err)
+	}
+	buf = make([]byte, 6)
+	if _, err := io.ReadFull(tr, buf); err != nil {
+		t.Fatalf("Unexpected error: %v", err)
+	}
+	if expected := []byte("Google"); !bytes.Equal(buf, expected) {
+		t.Errorf("Contents = %v, want %v", buf, expected)
+	}
+}
+
+func TestIncrementalRead(t *testing.T) {
+	test := gnuTarTest
+	f, err := os.Open(test.file)
+	if err != nil {
+		t.Fatalf("Unexpected error: %v", err)
+	}
+	defer f.Close()
+
+	tr := NewReader(f)
+
+	headers := test.headers
+	cksums := test.cksums
+	nread := 0
+
+	// loop over all files
+	for ; ; nread++ {
+		hdr, err := tr.Next()
+		if hdr == nil || err == io.EOF {
+			break
+		}
+
+		// check the header
+		if !reflect.DeepEqual(*hdr, *headers[nread]) {
+			t.Errorf("Incorrect header:\nhave %+v\nwant %+v",
+				*hdr, headers[nread])
+		}
+
+		// read file contents in little chunks EOF,
+		// checksumming all the way
+		h := md5.New()
+		rdbuf := make([]uint8, 8)
+		for {
+			nr, err := tr.Read(rdbuf)
+			if err == io.EOF {
+				break
+			}
+			if err != nil {
+				t.Errorf("Read: unexpected error %v\n", err)
+				break
+			}
+			h.Write(rdbuf[0:nr])
+		}
+		// verify checksum
+		have := fmt.Sprintf("%x", h.Sum(nil))
+		want := cksums[nread]
+		if want != have {
+			t.Errorf("Bad checksum on file %s:\nhave %+v\nwant %+v", hdr.Name, have, want)
+		}
+	}
+	if nread != len(headers) {
+		t.Errorf("Didn't process all files\nexpected: %d\nprocessed %d\n", len(headers), nread)
+	}
+}
+
+func TestNonSeekable(t *testing.T) {
+	test := gnuTarTest
+	f, err := os.Open(test.file)
+	if err != nil {
+		t.Fatalf("Unexpected error: %v", err)
+	}
+	defer f.Close()
+
+	type readerOnly struct {
+		io.Reader
+	}
+	tr := NewReader(readerOnly{f})
+	nread := 0
+
+	for ; ; nread++ {
+		_, err := tr.Next()
+		if err == io.EOF {
+			break
+		}
+		if err != nil {
+			t.Fatalf("Unexpected error: %v", err)
+		}
+	}
+
+	if nread != len(test.headers) {
+		t.Errorf("Didn't process all files\nexpected: %d\nprocessed %d\n", len(test.headers), nread)
+	}
+}
+
+func TestParsePAXHeader(t *testing.T) {
+	paxTests := [][3]string{
+		{"a", "a=name", "10 a=name\n"}, // Test case involving multiple acceptable lengths
+		{"a", "a=name", "9 a=name\n"},  // Test case involving multiple acceptable length
+		{"mtime", "mtime=1350244992.023960108", "30 mtime=1350244992.023960108\n"}}
+	for _, test := range paxTests {
+		key, expected, raw := test[0], test[1], test[2]
+		reader := bytes.NewReader([]byte(raw))
+		headers, err := parsePAX(reader)
+		if err != nil {
+			t.Errorf("Couldn't parse correctly formatted headers: %v", err)
+			continue
+		}
+		if strings.EqualFold(headers[key], expected) {
+			t.Errorf("mtime header incorrectly parsed: got %s, wanted %s", headers[key], expected)
+			continue
+		}
+		trailer := make([]byte, 100)
+		n, err := reader.Read(trailer)
+		if err != io.EOF || n != 0 {
+			t.Error("Buffer wasn't consumed")
+		}
+	}
+	badHeader := bytes.NewReader([]byte("3 somelongkey="))
+	if _, err := parsePAX(badHeader); err != ErrHeader {
+		t.Fatal("Unexpected success when parsing bad header")
+	}
+}
+
+func TestParsePAXTime(t *testing.T) {
+	// Some valid PAX time values
+	timestamps := map[string]time.Time{
+		"1350244992.023960108":  time.Unix(1350244992, 23960108), // The common case
+		"1350244992.02396010":   time.Unix(1350244992, 23960100), // Lower precision value
+		"1350244992.0239601089": time.Unix(1350244992, 23960108), // Higher precision value
+		"1350244992":            time.Unix(1350244992, 0),        // Low precision value
+	}
+	for input, expected := range timestamps {
+		ts, err := parsePAXTime(input)
+		if err != nil {
+			t.Fatal(err)
+		}
+		if !ts.Equal(expected) {
+			t.Fatalf("Time parsing failure %s %s", ts, expected)
+		}
+	}
+}
+
+func TestMergePAX(t *testing.T) {
+	hdr := new(Header)
+	// Test a string, integer, and time based value.
+	headers := map[string]string{
+		"path":  "a/b/c",
+		"uid":   "1000",
+		"mtime": "1350244992.023960108",
+	}
+	err := mergePAX(hdr, headers)
+	if err != nil {
+		t.Fatal(err)
+	}
+	want := &Header{
+		Name:    "a/b/c",
+		Uid:     1000,
+		ModTime: time.Unix(1350244992, 23960108),
+	}
+	if !reflect.DeepEqual(hdr, want) {
+		t.Errorf("incorrect merge: got %+v, want %+v", hdr, want)
+	}
+}
+
+func TestSparseEndToEnd(t *testing.T) {
+	test := sparseTarTest
+	f, err := os.Open(test.file)
+	if err != nil {
+		t.Fatalf("Unexpected error: %v", err)
+	}
+	defer f.Close()
+
+	tr := NewReader(f)
+
+	headers := test.headers
+	cksums := test.cksums
+	nread := 0
+
+	// loop over all files
+	for ; ; nread++ {
+		hdr, err := tr.Next()
+		if hdr == nil || err == io.EOF {
+			break
+		}
+
+		// check the header
+		if !reflect.DeepEqual(*hdr, *headers[nread]) {
+			t.Errorf("Incorrect header:\nhave %+v\nwant %+v",
+				*hdr, headers[nread])
+		}
+
+		// read and checksum the file data
+		h := md5.New()
+		_, err = io.Copy(h, tr)
+		if err != nil {
+			t.Fatalf("Unexpected error: %v", err)
+		}
+
+		// verify checksum
+		have := fmt.Sprintf("%x", h.Sum(nil))
+		want := cksums[nread]
+		if want != have {
+			t.Errorf("Bad checksum on file %s:\nhave %+v\nwant %+v", hdr.Name, have, want)
+		}
+	}
+	if nread != len(headers) {
+		t.Errorf("Didn't process all files\nexpected: %d\nprocessed %d\n", len(headers), nread)
+	}
+}
+
+type sparseFileReadTest struct {
+	sparseData []byte
+	sparseMap  []sparseEntry
+	realSize   int64
+	expected   []byte
+}
+
+var sparseFileReadTests = []sparseFileReadTest{
+	{
+		sparseData: []byte("abcde"),
+		sparseMap: []sparseEntry{
+			{offset: 0, numBytes: 2},
+			{offset: 5, numBytes: 3},
+		},
+		realSize: 8,
+		expected: []byte("ab\x00\x00\x00cde"),
+	},
+	{
+		sparseData: []byte("abcde"),
+		sparseMap: []sparseEntry{
+			{offset: 0, numBytes: 2},
+			{offset: 5, numBytes: 3},
+		},
+		realSize: 10,
+		expected: []byte("ab\x00\x00\x00cde\x00\x00"),
+	},
+	{
+		sparseData: []byte("abcde"),
+		sparseMap: []sparseEntry{
+			{offset: 1, numBytes: 3},
+			{offset: 6, numBytes: 2},
+		},
+		realSize: 8,
+		expected: []byte("\x00abc\x00\x00de"),
+	},
+	{
+		sparseData: []byte("abcde"),
+		sparseMap: []sparseEntry{
+			{offset: 1, numBytes: 3},
+			{offset: 6, numBytes: 2},
+		},
+		realSize: 10,
+		expected: []byte("\x00abc\x00\x00de\x00\x00"),
+	},
+	{
+		sparseData: []byte(""),
+		sparseMap:  nil,
+		realSize:   2,
+		expected:   []byte("\x00\x00"),
+	},
+}
+
+func TestSparseFileReader(t *testing.T) {
+	for i, test := range sparseFileReadTests {
+		r := bytes.NewReader(test.sparseData)
+		nb := int64(r.Len())
+		sfr := &sparseFileReader{
+			rfr: &regFileReader{r: r, nb: nb},
+			sp:  test.sparseMap,
+			pos: 0,
+			tot: test.realSize,
+		}
+		if sfr.numBytes() != nb {
+			t.Errorf("test %d: Before reading, sfr.numBytes() = %d, want %d", i, sfr.numBytes(), nb)
+		}
+		buf, err := ioutil.ReadAll(sfr)
+		if err != nil {
+			t.Errorf("test %d: Unexpected error: %v", i, err)
+		}
+		if e := test.expected; !bytes.Equal(buf, e) {
+			t.Errorf("test %d: Contents = %v, want %v", i, buf, e)
+		}
+		if sfr.numBytes() != 0 {
+			t.Errorf("test %d: After draining the reader, numBytes() was nonzero", i)
+		}
+	}
+}
+
+func TestSparseIncrementalRead(t *testing.T) {
+	sparseMap := []sparseEntry{{10, 2}}
+	sparseData := []byte("Go")
+	expected := "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00Go\x00\x00\x00\x00\x00\x00\x00\x00"
+
+	r := bytes.NewReader(sparseData)
+	nb := int64(r.Len())
+	sfr := &sparseFileReader{
+		rfr: &regFileReader{r: r, nb: nb},
+		sp:  sparseMap,
+		pos: 0,
+		tot: int64(len(expected)),
+	}
+
+	// We'll read the data 6 bytes at a time, with a hole of size 10 at
+	// the beginning and one of size 8 at the end.
+	var outputBuf bytes.Buffer
+	buf := make([]byte, 6)
+	for {
+		n, err := sfr.Read(buf)
+		if err == io.EOF {
+			break
+		}
+		if err != nil {
+			t.Errorf("Read: unexpected error %v\n", err)
+		}
+		if n > 0 {
+			_, err := outputBuf.Write(buf[:n])
+			if err != nil {
+				t.Errorf("Write: unexpected error %v\n", err)
+			}
+		}
+	}
+	got := outputBuf.String()
+	if got != expected {
+		t.Errorf("Contents = %v, want %v", got, expected)
+	}
+}
+
+func TestReadGNUSparseMap0x1(t *testing.T) {
+	headers := map[string]string{
+		paxGNUSparseNumBlocks: "4",
+		paxGNUSparseMap:       "0,5,10,5,20,5,30,5",
+	}
+	expected := []sparseEntry{
+		{offset: 0, numBytes: 5},
+		{offset: 10, numBytes: 5},
+		{offset: 20, numBytes: 5},
+		{offset: 30, numBytes: 5},
+	}
+
+	sp, err := readGNUSparseMap0x1(headers)
+	if err != nil {
+		t.Errorf("Unexpected error: %v", err)
+	}
+	if !reflect.DeepEqual(sp, expected) {
+		t.Errorf("Incorrect sparse map: got %v, wanted %v", sp, expected)
+	}
+}
+
+func TestReadGNUSparseMap1x0(t *testing.T) {
+	// This test uses lots of holes so the sparse header takes up more than two blocks
+	numEntries := 100
+	expected := make([]sparseEntry, 0, numEntries)
+	sparseMap := new(bytes.Buffer)
+
+	fmt.Fprintf(sparseMap, "%d\n", numEntries)
+	for i := 0; i < numEntries; i++ {
+		offset := int64(2048 * i)
+		numBytes := int64(1024)
+		expected = append(expected, sparseEntry{offset: offset, numBytes: numBytes})
+		fmt.Fprintf(sparseMap, "%d\n%d\n", offset, numBytes)
+	}
+
+	// Make the header the smallest multiple of blockSize that fits the sparseMap
+	headerBlocks := (sparseMap.Len() + blockSize - 1) / blockSize
+	bufLen := blockSize * headerBlocks
+	buf := make([]byte, bufLen)
+	copy(buf, sparseMap.Bytes())
+
+	// Get an reader to read the sparse map
+	r := bytes.NewReader(buf)
+
+	// Read the sparse map
+	sp, err := readGNUSparseMap1x0(r)
+	if err != nil {
+		t.Errorf("Unexpected error: %v", err)
+	}
+	if !reflect.DeepEqual(sp, expected) {
+		t.Errorf("Incorrect sparse map: got %v, wanted %v", sp, expected)
+	}
+}
+
+func TestUninitializedRead(t *testing.T) {
+	test := gnuTarTest
+	f, err := os.Open(test.file)
+	if err != nil {
+		t.Fatalf("Unexpected error: %v", err)
+	}
+	defer f.Close()
+
+	tr := NewReader(f)
+	_, err = tr.Read([]byte{})
+	if err == nil || err != io.EOF {
+		t.Errorf("Unexpected error: %v, wanted %v", err, io.EOF)
+	}
+
+}

vendor/src/github.com/vbatts/tar-split/archive/tar/stat_atim.go

@@ -0,0 +1,20 @@
+// Copyright 2012 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build linux dragonfly openbsd solaris
+
+package tar
+
+import (
+	"syscall"
+	"time"
+)
+
+func statAtime(st *syscall.Stat_t) time.Time {
+	return time.Unix(st.Atim.Unix())
+}
+
+func statCtime(st *syscall.Stat_t) time.Time {
+	return time.Unix(st.Ctim.Unix())
+}

vendor/src/github.com/vbatts/tar-split/archive/tar/stat_atimespec.go

@@ -0,0 +1,20 @@
+// Copyright 2012 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build darwin freebsd netbsd
+
+package tar
+
+import (
+	"syscall"
+	"time"
+)
+
+func statAtime(st *syscall.Stat_t) time.Time {
+	return time.Unix(st.Atimespec.Unix())
+}
+
+func statCtime(st *syscall.Stat_t) time.Time {
+	return time.Unix(st.Ctimespec.Unix())
+}

vendor/src/github.com/vbatts/tar-split/archive/tar/stat_unix.go

@@ -0,0 +1,32 @@
+// Copyright 2012 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build linux darwin dragonfly freebsd openbsd netbsd solaris
+
+package tar
+
+import (
+	"os"
+	"syscall"
+)
+
+func init() {
+	sysStat = statUnix
+}
+
+func statUnix(fi os.FileInfo, h *Header) error {
+	sys, ok := fi.Sys().(*syscall.Stat_t)
+	if !ok {
+		return nil
+	}
+	h.Uid = int(sys.Uid)
+	h.Gid = int(sys.Gid)
+	// TODO(bradfitz): populate username & group.  os/user
+	// doesn't cache LookupId lookups, and lacks group
+	// lookup functions.
+	h.AccessTime = statAtime(sys)
+	h.ChangeTime = statCtime(sys)
+	// TODO(bradfitz): major/minor device numbers?
+	return nil
+}

vendor/src/github.com/vbatts/tar-split/archive/tar/tar_test.go

@@ -0,0 +1,284 @@
+// Copyright 2012 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package tar
+
+import (
+	"bytes"
+	"io/ioutil"
+	"os"
+	"path"
+	"reflect"
+	"strings"
+	"testing"
+	"time"
+)
+
+func TestFileInfoHeader(t *testing.T) {
+	fi, err := os.Stat("testdata/small.txt")
+	if err != nil {
+		t.Fatal(err)
+	}
+	h, err := FileInfoHeader(fi, "")
+	if err != nil {
+		t.Fatalf("FileInfoHeader: %v", err)
+	}
+	if g, e := h.Name, "small.txt"; g != e {
+		t.Errorf("Name = %q; want %q", g, e)
+	}
+	if g, e := h.Mode, int64(fi.Mode().Perm())|c_ISREG; g != e {
+		t.Errorf("Mode = %#o; want %#o", g, e)
+	}
+	if g, e := h.Size, int64(5); g != e {
+		t.Errorf("Size = %v; want %v", g, e)
+	}
+	if g, e := h.ModTime, fi.ModTime(); !g.Equal(e) {
+		t.Errorf("ModTime = %v; want %v", g, e)
+	}
+	// FileInfoHeader should error when passing nil FileInfo
+	if _, err := FileInfoHeader(nil, ""); err == nil {
+		t.Fatalf("Expected error when passing nil to FileInfoHeader")
+	}
+}
+
+func TestFileInfoHeaderDir(t *testing.T) {
+	fi, err := os.Stat("testdata")
+	if err != nil {
+		t.Fatal(err)
+	}
+	h, err := FileInfoHeader(fi, "")
+	if err != nil {
+		t.Fatalf("FileInfoHeader: %v", err)
+	}
+	if g, e := h.Name, "testdata/"; g != e {
+		t.Errorf("Name = %q; want %q", g, e)
+	}
+	// Ignoring c_ISGID for golang.org/issue/4867
+	if g, e := h.Mode&^c_ISGID, int64(fi.Mode().Perm())|c_ISDIR; g != e {
+		t.Errorf("Mode = %#o; want %#o", g, e)
+	}
+	if g, e := h.Size, int64(0); g != e {
+		t.Errorf("Size = %v; want %v", g, e)
+	}
+	if g, e := h.ModTime, fi.ModTime(); !g.Equal(e) {
+		t.Errorf("ModTime = %v; want %v", g, e)
+	}
+}
+
+func TestFileInfoHeaderSymlink(t *testing.T) {
+	h, err := FileInfoHeader(symlink{}, "some-target")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if g, e := h.Name, "some-symlink"; g != e {
+		t.Errorf("Name = %q; want %q", g, e)
+	}
+	if g, e := h.Linkname, "some-target"; g != e {
+		t.Errorf("Linkname = %q; want %q", g, e)
+	}
+}
+
+type symlink struct{}
+
+func (symlink) Name() string       { return "some-symlink" }
+func (symlink) Size() int64        { return 0 }
+func (symlink) Mode() os.FileMode  { return os.ModeSymlink }
+func (symlink) ModTime() time.Time { return time.Time{} }
+func (symlink) IsDir() bool        { return false }
+func (symlink) Sys() interface{}   { return nil }
+
+func TestRoundTrip(t *testing.T) {
+	data := []byte("some file contents")
+
+	var b bytes.Buffer
+	tw := NewWriter(&b)
+	hdr := &Header{
+		Name:    "file.txt",
+		Uid:     1 << 21, // too big for 8 octal digits
+		Size:    int64(len(data)),
+		ModTime: time.Now(),
+	}
+	// tar only supports second precision.
+	hdr.ModTime = hdr.ModTime.Add(-time.Duration(hdr.ModTime.Nanosecond()) * time.Nanosecond)
+	if err := tw.WriteHeader(hdr); err != nil {
+		t.Fatalf("tw.WriteHeader: %v", err)
+	}
+	if _, err := tw.Write(data); err != nil {
+		t.Fatalf("tw.Write: %v", err)
+	}
+	if err := tw.Close(); err != nil {
+		t.Fatalf("tw.Close: %v", err)
+	}
+
+	// Read it back.
+	tr := NewReader(&b)
+	rHdr, err := tr.Next()
+	if err != nil {
+		t.Fatalf("tr.Next: %v", err)
+	}
+	if !reflect.DeepEqual(rHdr, hdr) {
+		t.Errorf("Header mismatch.\n got %+v\nwant %+v", rHdr, hdr)
+	}
+	rData, err := ioutil.ReadAll(tr)
+	if err != nil {
+		t.Fatalf("Read: %v", err)
+	}
+	if !bytes.Equal(rData, data) {
+		t.Errorf("Data mismatch.\n got %q\nwant %q", rData, data)
+	}
+}
+
+type headerRoundTripTest struct {
+	h  *Header
+	fm os.FileMode
+}
+
+func TestHeaderRoundTrip(t *testing.T) {
+	golden := []headerRoundTripTest{
+		// regular file.
+		{
+			h: &Header{
+				Name:     "test.txt",
+				Mode:     0644 | c_ISREG,
+				Size:     12,
+				ModTime:  time.Unix(1360600916, 0),
+				Typeflag: TypeReg,
+			},
+			fm: 0644,
+		},
+		// hard link.
+		{
+			h: &Header{
+				Name:     "hard.txt",
+				Mode:     0644 | c_ISLNK,
+				Size:     0,
+				ModTime:  time.Unix(1360600916, 0),
+				Typeflag: TypeLink,
+			},
+			fm: 0644 | os.ModeSymlink,
+		},
+		// symbolic link.
+		{
+			h: &Header{
+				Name:     "link.txt",
+				Mode:     0777 | c_ISLNK,
+				Size:     0,
+				ModTime:  time.Unix(1360600852, 0),
+				Typeflag: TypeSymlink,
+			},
+			fm: 0777 | os.ModeSymlink,
+		},
+		// character device node.
+		{
+			h: &Header{
+				Name:     "dev/null",
+				Mode:     0666 | c_ISCHR,
+				Size:     0,
+				ModTime:  time.Unix(1360578951, 0),
+				Typeflag: TypeChar,
+			},
+			fm: 0666 | os.ModeDevice | os.ModeCharDevice,
+		},
+		// block device node.
+		{
+			h: &Header{
+				Name:     "dev/sda",
+				Mode:     0660 | c_ISBLK,
+				Size:     0,
+				ModTime:  time.Unix(1360578954, 0),
+				Typeflag: TypeBlock,
+			},
+			fm: 0660 | os.ModeDevice,
+		},
+		// directory.
+		{
+			h: &Header{
+				Name:     "dir/",
+				Mode:     0755 | c_ISDIR,
+				Size:     0,
+				ModTime:  time.Unix(1360601116, 0),
+				Typeflag: TypeDir,
+			},
+			fm: 0755 | os.ModeDir,
+		},
+		// fifo node.
+		{
+			h: &Header{
+				Name:     "dev/initctl",
+				Mode:     0600 | c_ISFIFO,
+				Size:     0,
+				ModTime:  time.Unix(1360578949, 0),
+				Typeflag: TypeFifo,
+			},
+			fm: 0600 | os.ModeNamedPipe,
+		},
+		// setuid.
+		{
+			h: &Header{
+				Name:     "bin/su",
+				Mode:     0755 | c_ISREG | c_ISUID,
+				Size:     23232,
+				ModTime:  time.Unix(1355405093, 0),
+				Typeflag: TypeReg,
+			},
+			fm: 0755 | os.ModeSetuid,
+		},
+		// setguid.
+		{
+			h: &Header{
+				Name:     "group.txt",
+				Mode:     0750 | c_ISREG | c_ISGID,
+				Size:     0,
+				ModTime:  time.Unix(1360602346, 0),
+				Typeflag: TypeReg,
+			},
+			fm: 0750 | os.ModeSetgid,
+		},
+		// sticky.
+		{
+			h: &Header{
+				Name:     "sticky.txt",
+				Mode:     0600 | c_ISREG | c_ISVTX,
+				Size:     7,
+				ModTime:  time.Unix(1360602540, 0),
+				Typeflag: TypeReg,
+			},
+			fm: 0600 | os.ModeSticky,
+		},
+	}
+
+	for i, g := range golden {
+		fi := g.h.FileInfo()
+		h2, err := FileInfoHeader(fi, "")
+		if err != nil {
+			t.Error(err)
+			continue
+		}
+		if strings.Contains(fi.Name(), "/") {
+			t.Errorf("FileInfo of %q contains slash: %q", g.h.Name, fi.Name())
+		}
+		name := path.Base(g.h.Name)
+		if fi.IsDir() {
+			name += "/"
+		}
+		if got, want := h2.Name, name; got != want {
+			t.Errorf("i=%d: Name: got %v, want %v", i, got, want)
+		}
+		if got, want := h2.Size, g.h.Size; got != want {
+			t.Errorf("i=%d: Size: got %v, want %v", i, got, want)
+		}
+		if got, want := h2.Mode, g.h.Mode; got != want {
+			t.Errorf("i=%d: Mode: got %o, want %o", i, got, want)
+		}
+		if got, want := fi.Mode(), g.fm; got != want {
+			t.Errorf("i=%d: fi.Mode: got %o, want %o", i, got, want)
+		}
+		if got, want := h2.ModTime, g.h.ModTime; got != want {
+			t.Errorf("i=%d: ModTime: got %v, want %v", i, got, want)
+		}
+		if sysh, ok := fi.Sys().(*Header); !ok || sysh != g.h {
+			t.Errorf("i=%d: Sys didn't return original *Header", i)
+		}
+	}
+}

vendor/src/github.com/vbatts/tar-split/archive/tar/testdata/small.txt

@@ -0,0 +1 @@
+Kilts

vendor/src/github.com/vbatts/tar-split/archive/tar/testdata/small2.txt

@@ -0,0 +1 @@
+Google.com

vendor/src/github.com/vbatts/tar-split/archive/tar/writer.go

@@ -0,0 +1,396 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package tar
+
+// TODO(dsymonds):
+// - catch more errors (no first header, etc.)
+
+import (
+	"bytes"
+	"errors"
+	"fmt"
+	"io"
+	"os"
+	"path"
+	"strconv"
+	"strings"
+	"time"
+)
+
+var (
+	ErrWriteTooLong    = errors.New("archive/tar: write too long")
+	ErrFieldTooLong    = errors.New("archive/tar: header field too long")
+	ErrWriteAfterClose = errors.New("archive/tar: write after close")
+	errNameTooLong     = errors.New("archive/tar: name too long")
+	errInvalidHeader   = errors.New("archive/tar: header field too long or contains invalid values")
+)
+
+// A Writer provides sequential writing of a tar archive in POSIX.1 format.
+// A tar archive consists of a sequence of files.
+// Call WriteHeader to begin a new file, and then call Write to supply that file's data,
+// writing at most hdr.Size bytes in total.
+type Writer struct {
+	w          io.Writer
+	err        error
+	nb         int64 // number of unwritten bytes for current file entry
+	pad        int64 // amount of padding to write after current file entry
+	closed     bool
+	usedBinary bool            // whether the binary numeric field extension was used
+	preferPax  bool            // use pax header instead of binary numeric header
+	hdrBuff    [blockSize]byte // buffer to use in writeHeader when writing a regular header
+	paxHdrBuff [blockSize]byte // buffer to use in writeHeader when writing a pax header
+}
+
+// NewWriter creates a new Writer writing to w.
+func NewWriter(w io.Writer) *Writer { return &Writer{w: w} }
+
+// Flush finishes writing the current file (optional).
+func (tw *Writer) Flush() error {
+	if tw.nb > 0 {
+		tw.err = fmt.Errorf("archive/tar: missed writing %d bytes", tw.nb)
+		return tw.err
+	}
+
+	n := tw.nb + tw.pad
+	for n > 0 && tw.err == nil {
+		nr := n
+		if nr > blockSize {
+			nr = blockSize
+		}
+		var nw int
+		nw, tw.err = tw.w.Write(zeroBlock[0:nr])
+		n -= int64(nw)
+	}
+	tw.nb = 0
+	tw.pad = 0
+	return tw.err
+}
+
+// Write s into b, terminating it with a NUL if there is room.
+// If the value is too long for the field and allowPax is true add a paxheader record instead
+func (tw *Writer) cString(b []byte, s string, allowPax bool, paxKeyword string, paxHeaders map[string]string) {
+	needsPaxHeader := allowPax && len(s) > len(b) || !isASCII(s)
+	if needsPaxHeader {
+		paxHeaders[paxKeyword] = s
+		return
+	}
+	if len(s) > len(b) {
+		if tw.err == nil {
+			tw.err = ErrFieldTooLong
+		}
+		return
+	}
+	ascii := toASCII(s)
+	copy(b, ascii)
+	if len(ascii) < len(b) {
+		b[len(ascii)] = 0
+	}
+}
+
+// Encode x as an octal ASCII string and write it into b with leading zeros.
+func (tw *Writer) octal(b []byte, x int64) {
+	s := strconv.FormatInt(x, 8)
+	// leading zeros, but leave room for a NUL.
+	for len(s)+1 < len(b) {
+		s = "0" + s
+	}
+	tw.cString(b, s, false, paxNone, nil)
+}
+
+// Write x into b, either as octal or as binary (GNUtar/star extension).
+// If the value is too long for the field and writingPax is enabled both for the field and the add a paxheader record instead
+func (tw *Writer) numeric(b []byte, x int64, allowPax bool, paxKeyword string, paxHeaders map[string]string) {
+	// Try octal first.
+	s := strconv.FormatInt(x, 8)
+	if len(s) < len(b) {
+		tw.octal(b, x)
+		return
+	}
+
+	// If it is too long for octal, and pax is preferred, use a pax header
+	if allowPax && tw.preferPax {
+		tw.octal(b, 0)
+		s := strconv.FormatInt(x, 10)
+		paxHeaders[paxKeyword] = s
+		return
+	}
+
+	// Too big: use binary (big-endian).
+	tw.usedBinary = true
+	for i := len(b) - 1; x > 0 && i >= 0; i-- {
+		b[i] = byte(x)
+		x >>= 8
+	}
+	b[0] |= 0x80 // highest bit indicates binary format
+}
+
+var (
+	minTime = time.Unix(0, 0)
+	// There is room for 11 octal digits (33 bits) of mtime.
+	maxTime = minTime.Add((1<<33 - 1) * time.Second)
+)
+
+// WriteHeader writes hdr and prepares to accept the file's contents.
+// WriteHeader calls Flush if it is not the first header.
+// Calling after a Close will return ErrWriteAfterClose.
+func (tw *Writer) WriteHeader(hdr *Header) error {
+	return tw.writeHeader(hdr, true)
+}
+
+// WriteHeader writes hdr and prepares to accept the file's contents.
+// WriteHeader calls Flush if it is not the first header.
+// Calling after a Close will return ErrWriteAfterClose.
+// As this method is called internally by writePax header to allow it to
+// suppress writing the pax header.
+func (tw *Writer) writeHeader(hdr *Header, allowPax bool) error {
+	if tw.closed {
+		return ErrWriteAfterClose
+	}
+	if tw.err == nil {
+		tw.Flush()
+	}
+	if tw.err != nil {
+		return tw.err
+	}
+
+	// a map to hold pax header records, if any are needed
+	paxHeaders := make(map[string]string)
+
+	// TODO(shanemhansen): we might want to use PAX headers for
+	// subsecond time resolution, but for now let's just capture
+	// too long fields or non ascii characters
+
+	var header []byte
+
+	// We need to select which scratch buffer to use carefully,
+	// since this method is called recursively to write PAX headers.
+	// If allowPax is true, this is the non-recursive call, and we will use hdrBuff.
+	// If allowPax is false, we are being called by writePAXHeader, and hdrBuff is
+	// already being used by the non-recursive call, so we must use paxHdrBuff.
+	header = tw.hdrBuff[:]
+	if !allowPax {
+		header = tw.paxHdrBuff[:]
+	}
+	copy(header, zeroBlock)
+	s := slicer(header)
+
+	// keep a reference to the filename to allow to overwrite it later if we detect that we can use ustar longnames instead of pax
+	pathHeaderBytes := s.next(fileNameSize)
+
+	tw.cString(pathHeaderBytes, hdr.Name, true, paxPath, paxHeaders)
+
+	// Handle out of range ModTime carefully.
+	var modTime int64
+	if !hdr.ModTime.Before(minTime) && !hdr.ModTime.After(maxTime) {
+		modTime = hdr.ModTime.Unix()
+	}
+
+	tw.octal(s.next(8), hdr.Mode)                                   // 100:108
+	tw.numeric(s.next(8), int64(hdr.Uid), true, paxUid, paxHeaders) // 108:116
+	tw.numeric(s.next(8), int64(hdr.Gid), true, paxGid, paxHeaders) // 116:124
+	tw.numeric(s.next(12), hdr.Size, true, paxSize, paxHeaders)     // 124:136
+	tw.numeric(s.next(12), modTime, false, paxNone, nil)            // 136:148 --- consider using pax for finer granularity
+	s.next(8)                                                       // chksum (148:156)
+	s.next(1)[0] = hdr.Typeflag                                     // 156:157
+
+	tw.cString(s.next(100), hdr.Linkname, true, paxLinkpath, paxHeaders)
+
+	copy(s.next(8), []byte("ustar\x0000"))                        // 257:265
+	tw.cString(s.next(32), hdr.Uname, true, paxUname, paxHeaders) // 265:297
+	tw.cString(s.next(32), hdr.Gname, true, paxGname, paxHeaders) // 297:329
+	tw.numeric(s.next(8), hdr.Devmajor, false, paxNone, nil)      // 329:337
+	tw.numeric(s.next(8), hdr.Devminor, false, paxNone, nil)      // 337:345
+
+	// keep a reference to the prefix to allow to overwrite it later if we detect that we can use ustar longnames instead of pax
+	prefixHeaderBytes := s.next(155)
+	tw.cString(prefixHeaderBytes, "", false, paxNone, nil) // 345:500  prefix
+
+	// Use the GNU magic instead of POSIX magic if we used any GNU extensions.
+	if tw.usedBinary {
+		copy(header[257:265], []byte("ustar  \x00"))
+	}
+
+	_, paxPathUsed := paxHeaders[paxPath]
+	// try to use a ustar header when only the name is too long
+	if !tw.preferPax && len(paxHeaders) == 1 && paxPathUsed {
+		suffix := hdr.Name
+		prefix := ""
+		if len(hdr.Name) > fileNameSize && isASCII(hdr.Name) {
+			var err error
+			prefix, suffix, err = tw.splitUSTARLongName(hdr.Name)
+			if err == nil {
+				// ok we can use a ustar long name instead of pax, now correct the fields
+
+				// remove the path field from the pax header. this will suppress the pax header
+				delete(paxHeaders, paxPath)
+
+				// update the path fields
+				tw.cString(pathHeaderBytes, suffix, false, paxNone, nil)
+				tw.cString(prefixHeaderBytes, prefix, false, paxNone, nil)
+
+				// Use the ustar magic if we used ustar long names.
+				if len(prefix) > 0 && !tw.usedBinary {
+					copy(header[257:265], []byte("ustar\x00"))
+				}
+			}
+		}
+	}
+
+	// The chksum field is terminated by a NUL and a space.
+	// This is different from the other octal fields.
+	chksum, _ := checksum(header)
+	tw.octal(header[148:155], chksum)
+	header[155] = ' '
+
+	if tw.err != nil {
+		// problem with header; probably integer too big for a field.
+		return tw.err
+	}
+
+	if allowPax {
+		for k, v := range hdr.Xattrs {
+			paxHeaders[paxXattr+k] = v
+		}
+	}
+
+	if len(paxHeaders) > 0 {
+		if !allowPax {
+			return errInvalidHeader
+		}
+		if err := tw.writePAXHeader(hdr, paxHeaders); err != nil {
+			return err
+		}
+	}
+	tw.nb = int64(hdr.Size)
+	tw.pad = (blockSize - (tw.nb % blockSize)) % blockSize
+
+	_, tw.err = tw.w.Write(header)
+	return tw.err
+}
+
+// writeUSTARLongName splits a USTAR long name hdr.Name.
+// name must be < 256 characters. errNameTooLong is returned
+// if hdr.Name can't be split. The splitting heuristic
+// is compatible with gnu tar.
+func (tw *Writer) splitUSTARLongName(name string) (prefix, suffix string, err error) {
+	length := len(name)
+	if length > fileNamePrefixSize+1 {
+		length = fileNamePrefixSize + 1
+	} else if name[length-1] == '/' {
+		length--
+	}
+	i := strings.LastIndex(name[:length], "/")
+	// nlen contains the resulting length in the name field.
+	// plen contains the resulting length in the prefix field.
+	nlen := len(name) - i - 1
+	plen := i
+	if i <= 0 || nlen > fileNameSize || nlen == 0 || plen > fileNamePrefixSize {
+		err = errNameTooLong
+		return
+	}
+	prefix, suffix = name[:i], name[i+1:]
+	return
+}
+
+// writePaxHeader writes an extended pax header to the
+// archive.
+func (tw *Writer) writePAXHeader(hdr *Header, paxHeaders map[string]string) error {
+	// Prepare extended header
+	ext := new(Header)
+	ext.Typeflag = TypeXHeader
+	// Setting ModTime is required for reader parsing to
+	// succeed, and seems harmless enough.
+	ext.ModTime = hdr.ModTime
+	// The spec asks that we namespace our pseudo files
+	// with the current pid.
+	pid := os.Getpid()
+	dir, file := path.Split(hdr.Name)
+	fullName := path.Join(dir,
+		fmt.Sprintf("PaxHeaders.%d", pid), file)
+
+	ascii := toASCII(fullName)
+	if len(ascii) > 100 {
+		ascii = ascii[:100]
+	}
+	ext.Name = ascii
+	// Construct the body
+	var buf bytes.Buffer
+
+	for k, v := range paxHeaders {
+		fmt.Fprint(&buf, paxHeader(k+"="+v))
+	}
+
+	ext.Size = int64(len(buf.Bytes()))
+	if err := tw.writeHeader(ext, false); err != nil {
+		return err
+	}
+	if _, err := tw.Write(buf.Bytes()); err != nil {
+		return err
+	}
+	if err := tw.Flush(); err != nil {
+		return err
+	}
+	return nil
+}
+
+// paxHeader formats a single pax record, prefixing it with the appropriate length
+func paxHeader(msg string) string {
+	const padding = 2 // Extra padding for space and newline
+	size := len(msg) + padding
+	size += len(strconv.Itoa(size))
+	record := fmt.Sprintf("%d %s\n", size, msg)
+	if len(record) != size {
+		// Final adjustment if adding size increased
+		// the number of digits in size
+		size = len(record)
+		record = fmt.Sprintf("%d %s\n", size, msg)
+	}
+	return record
+}
+
+// Write writes to the current entry in the tar archive.
+// Write returns the error ErrWriteTooLong if more than
+// hdr.Size bytes are written after WriteHeader.
+func (tw *Writer) Write(b []byte) (n int, err error) {
+	if tw.closed {
+		err = ErrWriteTooLong
+		return
+	}
+	overwrite := false
+	if int64(len(b)) > tw.nb {
+		b = b[0:tw.nb]
+		overwrite = true
+	}
+	n, err = tw.w.Write(b)
+	tw.nb -= int64(n)
+	if err == nil && overwrite {
+		err = ErrWriteTooLong
+		return
+	}
+	tw.err = err
+	return
+}
+
+// Close closes the tar archive, flushing any unwritten
+// data to the underlying writer.
+func (tw *Writer) Close() error {
+	if tw.err != nil || tw.closed {
+		return tw.err
+	}
+	tw.Flush()
+	tw.closed = true
+	if tw.err != nil {
+		return tw.err
+	}
+
+	// trailer: two zero blocks
+	for i := 0; i < 2; i++ {
+		_, tw.err = tw.w.Write(zeroBlock)
+		if tw.err != nil {
+			break
+		}
+	}
+	return tw.err
+}

vendor/src/github.com/vbatts/tar-split/archive/tar/writer_test.go

@@ -0,0 +1,491 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package tar
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"os"
+	"reflect"
+	"strings"
+	"testing"
+	"testing/iotest"
+	"time"
+)
+
+type writerTestEntry struct {
+	header   *Header
+	contents string
+}
+
+type writerTest struct {
+	file    string // filename of expected output
+	entries []*writerTestEntry
+}
+
+var writerTests = []*writerTest{
+	// The writer test file was produced with this command:
+	// tar (GNU tar) 1.26
+	//   ln -s small.txt link.txt
+	//   tar -b 1 --format=ustar -c -f writer.tar small.txt small2.txt link.txt
+	{
+		file: "testdata/writer.tar",
+		entries: []*writerTestEntry{
+			{
+				header: &Header{
+					Name:     "small.txt",
+					Mode:     0640,
+					Uid:      73025,
+					Gid:      5000,
+					Size:     5,
+					ModTime:  time.Unix(1246508266, 0),
+					Typeflag: '0',
+					Uname:    "dsymonds",
+					Gname:    "eng",
+				},
+				contents: "Kilts",
+			},
+			{
+				header: &Header{
+					Name:     "small2.txt",
+					Mode:     0640,
+					Uid:      73025,
+					Gid:      5000,
+					Size:     11,
+					ModTime:  time.Unix(1245217492, 0),
+					Typeflag: '0',
+					Uname:    "dsymonds",
+					Gname:    "eng",
+				},
+				contents: "Google.com\n",
+			},
+			{
+				header: &Header{
+					Name:     "link.txt",
+					Mode:     0777,
+					Uid:      1000,
+					Gid:      1000,
+					Size:     0,
+					ModTime:  time.Unix(1314603082, 0),
+					Typeflag: '2',
+					Linkname: "small.txt",
+					Uname:    "strings",
+					Gname:    "strings",
+				},
+				// no contents
+			},
+		},
+	},
+	// The truncated test file was produced using these commands:
+	//   dd if=/dev/zero bs=1048576 count=16384 > /tmp/16gig.txt
+	//   tar -b 1 -c -f- /tmp/16gig.txt | dd bs=512 count=8 > writer-big.tar
+	{
+		file: "testdata/writer-big.tar",
+		entries: []*writerTestEntry{
+			{
+				header: &Header{
+					Name:     "tmp/16gig.txt",
+					Mode:     0640,
+					Uid:      73025,
+					Gid:      5000,
+					Size:     16 << 30,
+					ModTime:  time.Unix(1254699560, 0),
+					Typeflag: '0',
+					Uname:    "dsymonds",
+					Gname:    "eng",
+				},
+				// fake contents
+				contents: strings.Repeat("\x00", 4<<10),
+			},
+		},
+	},
+	// The truncated test file was produced using these commands:
+	//   dd if=/dev/zero bs=1048576 count=16384 > (longname/)*15 /16gig.txt
+	//   tar -b 1 -c -f- (longname/)*15 /16gig.txt | dd bs=512 count=8 > writer-big-long.tar
+	{
+		file: "testdata/writer-big-long.tar",
+		entries: []*writerTestEntry{
+			{
+				header: &Header{
+					Name:     strings.Repeat("longname/", 15) + "16gig.txt",
+					Mode:     0644,
+					Uid:      1000,
+					Gid:      1000,
+					Size:     16 << 30,
+					ModTime:  time.Unix(1399583047, 0),
+					Typeflag: '0',
+					Uname:    "guillaume",
+					Gname:    "guillaume",
+				},
+				// fake contents
+				contents: strings.Repeat("\x00", 4<<10),
+			},
+		},
+	},
+	// This file was produced using gnu tar 1.17
+	// gnutar  -b 4 --format=ustar (longname/)*15 + file.txt
+	{
+		file: "testdata/ustar.tar",
+		entries: []*writerTestEntry{
+			{
+				header: &Header{
+					Name:     strings.Repeat("longname/", 15) + "file.txt",
+					Mode:     0644,
+					Uid:      0765,
+					Gid:      024,
+					Size:     06,
+					ModTime:  time.Unix(1360135598, 0),
+					Typeflag: '0',
+					Uname:    "shane",
+					Gname:    "staff",
+				},
+				contents: "hello\n",
+			},
+		},
+	},
+}
+
+// Render byte array in a two-character hexadecimal string, spaced for easy visual inspection.
+func bytestr(offset int, b []byte) string {
+	const rowLen = 32
+	s := fmt.Sprintf("%04x ", offset)
+	for _, ch := range b {
+		switch {
+		case '0' <= ch && ch <= '9', 'A' <= ch && ch <= 'Z', 'a' <= ch && ch <= 'z':
+			s += fmt.Sprintf("  %c", ch)
+		default:
+			s += fmt.Sprintf(" %02x", ch)
+		}
+	}
+	return s
+}
+
+// Render a pseudo-diff between two blocks of bytes.
+func bytediff(a []byte, b []byte) string {
+	const rowLen = 32
+	s := fmt.Sprintf("(%d bytes vs. %d bytes)\n", len(a), len(b))
+	for offset := 0; len(a)+len(b) > 0; offset += rowLen {
+		na, nb := rowLen, rowLen
+		if na > len(a) {
+			na = len(a)
+		}
+		if nb > len(b) {
+			nb = len(b)
+		}
+		sa := bytestr(offset, a[0:na])
+		sb := bytestr(offset, b[0:nb])
+		if sa != sb {
+			s += fmt.Sprintf("-%v\n+%v\n", sa, sb)
+		}
+		a = a[na:]
+		b = b[nb:]
+	}
+	return s
+}
+
+func TestWriter(t *testing.T) {
+testLoop:
+	for i, test := range writerTests {
+		expected, err := ioutil.ReadFile(test.file)
+		if err != nil {
+			t.Errorf("test %d: Unexpected error: %v", i, err)
+			continue
+		}
+
+		buf := new(bytes.Buffer)
+		tw := NewWriter(iotest.TruncateWriter(buf, 4<<10)) // only catch the first 4 KB
+		big := false
+		for j, entry := range test.entries {
+			big = big || entry.header.Size > 1<<10
+			if err := tw.WriteHeader(entry.header); err != nil {
+				t.Errorf("test %d, entry %d: Failed writing header: %v", i, j, err)
+				continue testLoop
+			}
+			if _, err := io.WriteString(tw, entry.contents); err != nil {
+				t.Errorf("test %d, entry %d: Failed writing contents: %v", i, j, err)
+				continue testLoop
+			}
+		}
+		// Only interested in Close failures for the small tests.
+		if err := tw.Close(); err != nil && !big {
+			t.Errorf("test %d: Failed closing archive: %v", i, err)
+			continue testLoop
+		}
+
+		actual := buf.Bytes()
+		if !bytes.Equal(expected, actual) {
+			t.Errorf("test %d: Incorrect result: (-=expected, +=actual)\n%v",
+				i, bytediff(expected, actual))
+		}
+		if testing.Short() { // The second test is expensive.
+			break
+		}
+	}
+}
+
+func TestPax(t *testing.T) {
+	// Create an archive with a large name
+	fileinfo, err := os.Stat("testdata/small.txt")
+	if err != nil {
+		t.Fatal(err)
+	}
+	hdr, err := FileInfoHeader(fileinfo, "")
+	if err != nil {
+		t.Fatalf("os.Stat: %v", err)
+	}
+	// Force a PAX long name to be written
+	longName := strings.Repeat("ab", 100)
+	contents := strings.Repeat(" ", int(hdr.Size))
+	hdr.Name = longName
+	var buf bytes.Buffer
+	writer := NewWriter(&buf)
+	if err := writer.WriteHeader(hdr); err != nil {
+		t.Fatal(err)
+	}
+	if _, err = writer.Write([]byte(contents)); err != nil {
+		t.Fatal(err)
+	}
+	if err := writer.Close(); err != nil {
+		t.Fatal(err)
+	}
+	// Simple test to make sure PAX extensions are in effect
+	if !bytes.Contains(buf.Bytes(), []byte("PaxHeaders.")) {
+		t.Fatal("Expected at least one PAX header to be written.")
+	}
+	// Test that we can get a long name back out of the archive.
+	reader := NewReader(&buf)
+	hdr, err = reader.Next()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if hdr.Name != longName {
+		t.Fatal("Couldn't recover long file name")
+	}
+}
+
+func TestPaxSymlink(t *testing.T) {
+	// Create an archive with a large linkname
+	fileinfo, err := os.Stat("testdata/small.txt")
+	if err != nil {
+		t.Fatal(err)
+	}
+	hdr, err := FileInfoHeader(fileinfo, "")
+	hdr.Typeflag = TypeSymlink
+	if err != nil {
+		t.Fatalf("os.Stat:1 %v", err)
+	}
+	// Force a PAX long linkname to be written
+	longLinkname := strings.Repeat("1234567890/1234567890", 10)
+	hdr.Linkname = longLinkname
+
+	hdr.Size = 0
+	var buf bytes.Buffer
+	writer := NewWriter(&buf)
+	if err := writer.WriteHeader(hdr); err != nil {
+		t.Fatal(err)
+	}
+	if err := writer.Close(); err != nil {
+		t.Fatal(err)
+	}
+	// Simple test to make sure PAX extensions are in effect
+	if !bytes.Contains(buf.Bytes(), []byte("PaxHeaders.")) {
+		t.Fatal("Expected at least one PAX header to be written.")
+	}
+	// Test that we can get a long name back out of the archive.
+	reader := NewReader(&buf)
+	hdr, err = reader.Next()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if hdr.Linkname != longLinkname {
+		t.Fatal("Couldn't recover long link name")
+	}
+}
+
+func TestPaxNonAscii(t *testing.T) {
+	// Create an archive with non ascii. These should trigger a pax header
+	// because pax headers have a defined utf-8 encoding.
+	fileinfo, err := os.Stat("testdata/small.txt")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	hdr, err := FileInfoHeader(fileinfo, "")
+	if err != nil {
+		t.Fatalf("os.Stat:1 %v", err)
+	}
+
+	// some sample data
+	chineseFilename := "文件名"
+	chineseGroupname := "組"
+	chineseUsername := "用戶名"
+
+	hdr.Name = chineseFilename
+	hdr.Gname = chineseGroupname
+	hdr.Uname = chineseUsername
+
+	contents := strings.Repeat(" ", int(hdr.Size))
+
+	var buf bytes.Buffer
+	writer := NewWriter(&buf)
+	if err := writer.WriteHeader(hdr); err != nil {
+		t.Fatal(err)
+	}
+	if _, err = writer.Write([]byte(contents)); err != nil {
+		t.Fatal(err)
+	}
+	if err := writer.Close(); err != nil {
+		t.Fatal(err)
+	}
+	// Simple test to make sure PAX extensions are in effect
+	if !bytes.Contains(buf.Bytes(), []byte("PaxHeaders.")) {
+		t.Fatal("Expected at least one PAX header to be written.")
+	}
+	// Test that we can get a long name back out of the archive.
+	reader := NewReader(&buf)
+	hdr, err = reader.Next()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if hdr.Name != chineseFilename {
+		t.Fatal("Couldn't recover unicode name")
+	}
+	if hdr.Gname != chineseGroupname {
+		t.Fatal("Couldn't recover unicode group")
+	}
+	if hdr.Uname != chineseUsername {
+		t.Fatal("Couldn't recover unicode user")
+	}
+}
+
+func TestPaxXattrs(t *testing.T) {
+	xattrs := map[string]string{
+		"user.key": "value",
+	}
+
+	// Create an archive with an xattr
+	fileinfo, err := os.Stat("testdata/small.txt")
+	if err != nil {
+		t.Fatal(err)
+	}
+	hdr, err := FileInfoHeader(fileinfo, "")
+	if err != nil {
+		t.Fatalf("os.Stat: %v", err)
+	}
+	contents := "Kilts"
+	hdr.Xattrs = xattrs
+	var buf bytes.Buffer
+	writer := NewWriter(&buf)
+	if err := writer.WriteHeader(hdr); err != nil {
+		t.Fatal(err)
+	}
+	if _, err = writer.Write([]byte(contents)); err != nil {
+		t.Fatal(err)
+	}
+	if err := writer.Close(); err != nil {
+		t.Fatal(err)
+	}
+	// Test that we can get the xattrs back out of the archive.
+	reader := NewReader(&buf)
+	hdr, err = reader.Next()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !reflect.DeepEqual(hdr.Xattrs, xattrs) {
+		t.Fatalf("xattrs did not survive round trip: got %+v, want %+v",
+			hdr.Xattrs, xattrs)
+	}
+}
+
+func TestPAXHeader(t *testing.T) {
+	medName := strings.Repeat("CD", 50)
+	longName := strings.Repeat("AB", 100)
+	paxTests := [][2]string{
+		{paxPath + "=/etc/hosts", "19 path=/etc/hosts\n"},
+		{"a=b", "6 a=b\n"},          // Single digit length
+		{"a=names", "11 a=names\n"}, // Test case involving carries
+		{paxPath + "=" + longName, fmt.Sprintf("210 path=%s\n", longName)},
+		{paxPath + "=" + medName, fmt.Sprintf("110 path=%s\n", medName)}}
+
+	for _, test := range paxTests {
+		key, expected := test[0], test[1]
+		if result := paxHeader(key); result != expected {
+			t.Fatalf("paxHeader: got %s, expected %s", result, expected)
+		}
+	}
+}
+
+func TestUSTARLongName(t *testing.T) {
+	// Create an archive with a path that failed to split with USTAR extension in previous versions.
+	fileinfo, err := os.Stat("testdata/small.txt")
+	if err != nil {
+		t.Fatal(err)
+	}
+	hdr, err := FileInfoHeader(fileinfo, "")
+	hdr.Typeflag = TypeDir
+	if err != nil {
+		t.Fatalf("os.Stat:1 %v", err)
+	}
+	// Force a PAX long name to be written. The name was taken from a practical example
+	// that fails and replaced ever char through numbers to anonymize the sample.
+	longName := "/0000_0000000/00000-000000000/0000_0000000/00000-0000000000000/0000_0000000/00000-0000000-00000000/0000_0000000/00000000/0000_0000000/000/0000_0000000/00000000v00/0000_0000000/000000/0000_0000000/0000000/0000_0000000/00000y-00/0000/0000/00000000/0x000000/"
+	hdr.Name = longName
+
+	hdr.Size = 0
+	var buf bytes.Buffer
+	writer := NewWriter(&buf)
+	if err := writer.WriteHeader(hdr); err != nil {
+		t.Fatal(err)
+	}
+	if err := writer.Close(); err != nil {
+		t.Fatal(err)
+	}
+	// Test that we can get a long name back out of the archive.
+	reader := NewReader(&buf)
+	hdr, err = reader.Next()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if hdr.Name != longName {
+		t.Fatal("Couldn't recover long name")
+	}
+}
+
+func TestValidTypeflagWithPAXHeader(t *testing.T) {
+	var buffer bytes.Buffer
+	tw := NewWriter(&buffer)
+
+	fileName := strings.Repeat("ab", 100)
+
+	hdr := &Header{
+		Name:     fileName,
+		Size:     4,
+		Typeflag: 0,
+	}
+	if err := tw.WriteHeader(hdr); err != nil {
+		t.Fatalf("Failed to write header: %s", err)
+	}
+	if _, err := tw.Write([]byte("fooo")); err != nil {
+		t.Fatalf("Failed to write the file's data: %s", err)
+	}
+	tw.Close()
+
+	tr := NewReader(&buffer)
+
+	for {
+		header, err := tr.Next()
+		if err == io.EOF {
+			break
+		}
+		if err != nil {
+			t.Fatalf("Failed to read header: %s", err)
+		}
+		if header.Typeflag != 0 {
+			t.Fatalf("Typeflag should've been 0, found %d", header.Typeflag)
+		}
+	}
+}

vendor/src/github.com/vbatts/tar-split/checksize.go

@@ -0,0 +1,111 @@
+// +build ignore
+
+package main
+
+import (
+	"archive/tar"
+	"compress/gzip"
+	"flag"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"log"
+	"os"
+
+	"github.com/vbatts/tar-split/tar/asm"
+	"github.com/vbatts/tar-split/tar/storage"
+)
+
+var (
+	flCleanup = flag.Bool("cleanup", true, "cleanup tempfiles")
+)
+
+func main() {
+	flag.Parse()
+
+	for _, arg := range flag.Args() {
+		fh, err := os.Open(arg)
+		if err != nil {
+			log.Fatal(err)
+		}
+		defer fh.Close()
+		fi, err := fh.Stat()
+		if err != nil {
+			log.Fatal(err)
+		}
+		fmt.Printf("inspecting %q (size %dk)\n", fh.Name(), fi.Size()/1024)
+
+		packFh, err := ioutil.TempFile("", "packed.")
+		if err != nil {
+			log.Fatal(err)
+		}
+		defer packFh.Close()
+		if *flCleanup {
+			defer os.Remove(packFh.Name())
+		}
+
+		sp := storage.NewJSONPacker(packFh)
+		fp := storage.NewDiscardFilePutter()
+		dissam, err := asm.NewInputTarStream(fh, sp, fp)
+		if err != nil {
+			log.Fatal(err)
+		}
+
+		var num int
+		tr := tar.NewReader(dissam)
+		for {
+			_, err = tr.Next()
+			if err != nil {
+				if err == io.EOF {
+					break
+				}
+				log.Fatal(err)
+			}
+			num++
+			if _, err := io.Copy(ioutil.Discard, tr); err != nil {
+				log.Fatal(err)
+			}
+		}
+		fmt.Printf(" -- number of files: %d\n", num)
+
+		if err := packFh.Sync(); err != nil {
+			log.Fatal(err)
+		}
+
+		fi, err = packFh.Stat()
+		if err != nil {
+			log.Fatal(err)
+		}
+		fmt.Printf(" -- size of metadata uncompressed: %dk\n", fi.Size()/1024)
+
+		gzPackFh, err := ioutil.TempFile("", "packed.gz.")
+		if err != nil {
+			log.Fatal(err)
+		}
+		defer gzPackFh.Close()
+		if *flCleanup {
+			defer os.Remove(gzPackFh.Name())
+		}
+
+		gzWrtr := gzip.NewWriter(gzPackFh)
+
+		if _, err := packFh.Seek(0, 0); err != nil {
+			log.Fatal(err)
+		}
+
+		if _, err := io.Copy(gzWrtr, packFh); err != nil {
+			log.Fatal(err)
+		}
+		gzWrtr.Close()
+
+		if err := gzPackFh.Sync(); err != nil {
+			log.Fatal(err)
+		}
+
+		fi, err = gzPackFh.Stat()
+		if err != nil {
+			log.Fatal(err)
+		}
+		fmt.Printf(" -- size of gzip compressed metadata: %dk\n", fi.Size()/1024)
+	}
+}

vendor/src/github.com/vbatts/tar-split/cmd/tar-split/README.md

@@ -0,0 +1,25 @@
+## tar-split utility
+
+
+## Usage
+
+### Disassembly
+
+```bash
+$ sha256sum archive.tar 
+d734a748db93ec873392470510b8a1c88929abd8fae2540dc43d5b26f7537868  archive.tar
+$ mkdir ./x
+$ tar-split d --output tar-data.json.gz ./archive.tar | tar -C ./x -x
+time="2015-07-20T15:45:04-04:00" level=info msg="created tar-data.json.gz from ./archive.tar (read 204800 bytes)"
+```
+
+### Assembly
+
+```bash
+$ tar-split a --output new.tar --input ./tar-data.json.gz  --path ./x/
+INFO[0000] created new.tar from ./x/ and ./tar-data.json.gz (wrote 204800 bytes)
+$ sha256sum new.tar 
+d734a748db93ec873392470510b8a1c88929abd8fae2540dc43d5b26f7537868  new.tar
+```
+
+

vendor/src/github.com/vbatts/tar-split/cmd/tar-split/main.go

@@ -0,0 +1,175 @@
+// go:generate git tag | tail -1
+package main
+
+import (
+	"compress/gzip"
+	"io"
+	"os"
+
+	"github.com/Sirupsen/logrus"
+	"github.com/codegangsta/cli"
+	"github.com/vbatts/tar-split/tar/asm"
+	"github.com/vbatts/tar-split/tar/storage"
+)
+
+func main() {
+	app := cli.NewApp()
+	app.Name = "tar-split"
+	app.Usage = "tar assembly and disassembly utility"
+	app.Version = "0.9.2"
+	app.Author = "Vincent Batts"
+	app.Email = "vbatts@hashbangbash.com"
+	app.Action = cli.ShowAppHelp
+	app.Before = func(c *cli.Context) error {
+		logrus.SetOutput(os.Stderr)
+		if c.Bool("debug") {
+			logrus.SetLevel(logrus.DebugLevel)
+		}
+		return nil
+	}
+	app.Flags = []cli.Flag{
+		cli.BoolFlag{
+			Name:  "debug, D",
+			Usage: "debug output",
+			// defaults to false
+		},
+	}
+	app.Commands = []cli.Command{
+		{
+			Name:    "disasm",
+			Aliases: []string{"d"},
+			Usage:   "disassemble the input tar stream",
+			Action:  CommandDisasm,
+			Flags: []cli.Flag{
+				cli.StringFlag{
+					Name:  "output",
+					Value: "tar-data.json.gz",
+					Usage: "output of disassembled tar stream",
+				},
+			},
+		},
+		{
+			Name:    "asm",
+			Aliases: []string{"a"},
+			Usage:   "assemble tar stream",
+			Action:  CommandAsm,
+			Flags: []cli.Flag{
+				cli.StringFlag{
+					Name:  "input",
+					Value: "tar-data.json.gz",
+					Usage: "input of disassembled tar stream",
+				},
+				cli.StringFlag{
+					Name:  "output",
+					Value: "-",
+					Usage: "reassembled tar archive",
+				},
+				cli.StringFlag{
+					Name:  "path",
+					Value: "",
+					Usage: "relative path of extracted tar",
+				},
+			},
+		},
+	}
+
+	if err := app.Run(os.Args); err != nil {
+		logrus.Fatal(err)
+	}
+}
+
+func CommandDisasm(c *cli.Context) {
+	if len(c.Args()) != 1 {
+		logrus.Fatalf("please specify tar to be disabled <NAME|->")
+	}
+	if len(c.String("output")) == 0 {
+		logrus.Fatalf("--output filename must be set")
+	}
+
+	// Set up the tar input stream
+	var inputStream io.Reader
+	if c.Args()[0] == "-" {
+		inputStream = os.Stdin
+	} else {
+		fh, err := os.Open(c.Args()[0])
+		if err != nil {
+			logrus.Fatal(err)
+		}
+		defer fh.Close()
+		inputStream = fh
+	}
+
+	// Set up the metadata storage
+	mf, err := os.OpenFile(c.String("output"), os.O_CREATE|os.O_WRONLY|os.O_TRUNC, os.FileMode(0600))
+	if err != nil {
+		logrus.Fatal(err)
+	}
+	defer mf.Close()
+	mfz := gzip.NewWriter(mf)
+	defer mfz.Close()
+	metaPacker := storage.NewJSONPacker(mfz)
+
+	// we're passing nil here for the file putter, because the ApplyDiff will
+	// handle the extraction of the archive
+	its, err := asm.NewInputTarStream(inputStream, metaPacker, nil)
+	if err != nil {
+		logrus.Fatal(err)
+	}
+	i, err := io.Copy(os.Stdout, its)
+	if err != nil {
+		logrus.Fatal(err)
+	}
+	logrus.Infof("created %s from %s (read %d bytes)", c.String("output"), c.Args()[0], i)
+}
+
+func CommandAsm(c *cli.Context) {
+	if len(c.Args()) > 0 {
+		logrus.Warnf("%d additional arguments passed are ignored", len(c.Args()))
+	}
+	if len(c.String("input")) == 0 {
+		logrus.Fatalf("--input filename must be set")
+	}
+	if len(c.String("output")) == 0 {
+		logrus.Fatalf("--output filename must be set ([FILENAME|-])")
+	}
+	if len(c.String("path")) == 0 {
+		logrus.Fatalf("--path must be set")
+	}
+
+	var outputStream io.Writer
+	if c.String("output") == "-" {
+		outputStream = os.Stdout
+	} else {
+		fh, err := os.Create(c.String("output"))
+		if err != nil {
+			logrus.Fatal(err)
+		}
+		defer fh.Close()
+		outputStream = fh
+	}
+
+	// Get the tar metadata reader
+	mf, err := os.Open(c.String("input"))
+	if err != nil {
+		logrus.Fatal(err)
+	}
+	defer mf.Close()
+	mfz, err := gzip.NewReader(mf)
+	if err != nil {
+		logrus.Fatal(err)
+	}
+	defer mfz.Close()
+
+	metaUnpacker := storage.NewJSONUnpacker(mfz)
+	// XXX maybe get the absolute path here
+	fileGetter := storage.NewPathFileGetter(c.String("path"))
+
+	ots := asm.NewOutputTarStream(fileGetter, metaUnpacker)
+	defer ots.Close()
+	i, err := io.Copy(outputStream, ots)
+	if err != nil {
+		logrus.Fatal(err)
+	}
+
+	logrus.Infof("created %s from %s and %s (wrote %d bytes)", c.String("output"), c.String("path"), c.String("input"), i)
+}

vendor/src/github.com/vbatts/tar-split/concept/main.go

@@ -0,0 +1,91 @@
+// +build ignore
+
+package main
+
+import (
+	"flag"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"log"
+	"os"
+
+	"github.com/vbatts/tar-split/archive/tar"
+)
+
+func main() {
+	flag.Parse()
+	log.SetOutput(os.Stderr)
+	for _, arg := range flag.Args() {
+		func() {
+			// Open the tar archive
+			fh, err := os.Open(arg)
+			if err != nil {
+				log.Fatal(err, arg)
+			}
+			defer fh.Close()
+
+			output, err := os.Create(fmt.Sprintf("%s.out", arg))
+			if err != nil {
+				log.Fatal(err)
+			}
+			defer output.Close()
+			log.Printf("writing %q to %q", fh.Name(), output.Name())
+
+			fi, err := fh.Stat()
+			if err != nil {
+				log.Fatal(err, fh.Name())
+			}
+			size := fi.Size()
+			var sum int64
+			tr := tar.NewReader(fh)
+			tr.RawAccounting = true
+			for {
+				hdr, err := tr.Next()
+				if err != nil {
+					if err != io.EOF {
+						log.Println(err)
+					}
+					// even when an EOF is reached, there is often 1024 null bytes on
+					// the end of an archive. Collect them too.
+					post := tr.RawBytes()
+					output.Write(post)
+					sum += int64(len(post))
+
+					fmt.Printf("EOF padding: %d\n", len(post))
+					break
+				}
+
+				pre := tr.RawBytes()
+				output.Write(pre)
+				sum += int64(len(pre))
+
+				var i int64
+				if i, err = io.Copy(output, tr); err != nil {
+					log.Println(err)
+					break
+				}
+				sum += i
+
+				fmt.Println(hdr.Name, "pre:", len(pre), "read:", i)
+			}
+
+			// it is allowable, and not uncommon that there is further padding on the
+			// end of an archive, apart from the expected 1024 null bytes
+			remainder, err := ioutil.ReadAll(fh)
+			if err != nil && err != io.EOF {
+				log.Fatal(err, fh.Name())
+			}
+			output.Write(remainder)
+			sum += int64(len(remainder))
+			fmt.Printf("Remainder: %d\n", len(remainder))
+
+			if size != sum {
+				fmt.Printf("Size: %d; Sum: %d; Diff: %d\n", size, sum, size-sum)
+				fmt.Printf("Compare like `cmp -bl %s %s | less`\n", fh.Name(), output.Name())
+			} else {
+				fmt.Printf("Size: %d; Sum: %d\n", size, sum)
+			}
+		}()
+	}
+}

vendor/src/github.com/vbatts/tar-split/tar/asm/README.md

@@ -0,0 +1,44 @@
+asm
+===
+
+This library for assembly and disassembly of tar archives, facilitated by
+`github.com/vbatts/tar-split/tar/storage`.
+
+
+Concerns
+--------
+
+For completely safe assembly/disassembly, there will need to be a Content
+Addressable Storage (CAS) directory, that maps to a checksum in the
+`storage.Entity` of `storage.FileType`.
+
+This is due to the fact that tar archives _can_ allow multiple records for the
+same path, but the last one effectively wins. Even if the prior records had a
+different payload. 
+
+In this way, when assembling an archive from relative paths, if the archive has
+multiple entries for the same path, then all payloads read in from a relative
+path would be identical.
+
+
+Thoughts
+--------
+
+Have a look-aside directory or storage. This way when a clobbering record is
+encountered from the tar stream, then the payload of the prior/existing file is
+stored to the CAS. This way the clobbering record's file payload can be
+extracted, but we'll have preserved the payload needed to reassemble a precise
+tar archive.
+
+clobbered/path/to/file.[0-N]
+
+*alternatively*
+
+We could just _not_ support tar streams that have clobbering file paths.
+Appending records to the archive is not incredibly common, and doesn't happen
+by default for most implementations.  Not supporting them wouldn't be a
+security concern either, as if it did occur, we would reassemble an archive
+that doesn't validate signature/checksum, so it shouldn't be trusted anyway.
+
+Otherwise, this will allow us to defer support for appended files as a FUTURE FEATURE.
+

vendor/src/github.com/vbatts/tar-split/tar/asm/assemble.go

@@ -0,0 +1,68 @@
+package asm
+
+import (
+	"bytes"
+	"fmt"
+	"hash/crc64"
+	"io"
+
+	"github.com/vbatts/tar-split/tar/storage"
+)
+
+// NewOutputTarStream returns an io.ReadCloser that is an assemble tar archive
+// stream.
+//
+// It takes a storage.FileGetter, for mapping the file payloads that are to be read in,
+// and a storage.Unpacker, which has access to the rawbytes and file order
+// metadata. With the combination of these two items, a precise assembled Tar
+// archive is possible.
+func NewOutputTarStream(fg storage.FileGetter, up storage.Unpacker) io.ReadCloser {
+	// ... Since these are interfaces, this is possible, so let's not have a nil pointer
+	if fg == nil || up == nil {
+		return nil
+	}
+	pr, pw := io.Pipe()
+	go func() {
+		for {
+			entry, err := up.Next()
+			if err != nil {
+				pw.CloseWithError(err)
+				return
+			}
+			switch entry.Type {
+			case storage.SegmentType:
+				if _, err := pw.Write(entry.Payload); err != nil {
+					pw.CloseWithError(err)
+					return
+				}
+			case storage.FileType:
+				if entry.Size == 0 {
+					continue
+				}
+				fh, err := fg.Get(entry.Name)
+				if err != nil {
+					pw.CloseWithError(err)
+					return
+				}
+				c := crc64.New(storage.CRCTable)
+				tRdr := io.TeeReader(fh, c)
+				if _, err := io.Copy(pw, tRdr); err != nil {
+					fh.Close()
+					pw.CloseWithError(err)
+					return
+				}
+				if !bytes.Equal(c.Sum(nil), entry.Payload) {
+					// I would rather this be a comparable ErrInvalidChecksum or such,
+					// but since it's coming through the PipeReader, the context of
+					// _which_ file would be lost...
+					fh.Close()
+					pw.CloseWithError(fmt.Errorf("file integrity checksum failed for %q", entry.Name))
+					return
+				}
+				fh.Close()
+			}
+		}
+		pw.Close()
+	}()
+	return pr
+}

vendor/src/github.com/vbatts/tar-split/tar/asm/assemble_test.go

@@ -0,0 +1,181 @@
+package asm
+
+import (
+	"bytes"
+	"compress/gzip"
+	"crypto/sha1"
+	"fmt"
+	"hash/crc64"
+	"io"
+	"io/ioutil"
+	"os"
+	"testing"
+
+	"github.com/vbatts/tar-split/tar/storage"
+)
+
+var entries = []struct {
+	Entry storage.Entry
+	Body  []byte
+}{
+	{
+		Entry: storage.Entry{
+			Type:    storage.FileType,
+			Name:    "./hurr.txt",
+			Payload: []byte{2, 116, 164, 177, 171, 236, 107, 78},
+			Size:    20,
+		},
+		Body: []byte("imma hurr til I derp"),
+	},
+	{
+		Entry: storage.Entry{
+			Type:    storage.FileType,
+			Name:    "./ermahgerd.txt",
+			Payload: []byte{126, 72, 89, 239, 230, 252, 160, 187},
+			Size:    26,
+		},
+		Body: []byte("café con leche, por favor"),
+	},
+}
+var entriesMangled = []struct {
+	Entry storage.Entry
+	Body  []byte
+}{
+	{
+		Entry: storage.Entry{
+			Type:    storage.FileType,
+			Name:    "./hurr.txt",
+			Payload: []byte{3, 116, 164, 177, 171, 236, 107, 78},
+			Size:    20,
+		},
+		// switch
+		Body: []byte("imma derp til I hurr"),
+	},
+	{
+		Entry: storage.Entry{
+			Type:    storage.FileType,
+			Name:    "./ermahgerd.txt",
+			Payload: []byte{127, 72, 89, 239, 230, 252, 160, 187},
+			Size:    26,
+		},
+		// san not con
+		Body: []byte("café sans leche, por favor"),
+	},
+}
+
+func TestTarStreamMangledGetterPutter(t *testing.T) {
+	fgp := storage.NewBufferFileGetPutter()
+
+	// first lets prep a GetPutter and Packer
+	for i := range entries {
+		if entries[i].Entry.Type == storage.FileType {
+			j, csum, err := fgp.Put(entries[i].Entry.Name, bytes.NewBuffer(entries[i].Body))
+			if err != nil {
+				t.Error(err)
+			}
+			if j != entries[i].Entry.Size {
+				t.Errorf("size %q: expected %d; got %d",
+					entries[i].Entry.Name,
+					entries[i].Entry.Size,
+					j)
+			}
+			if !bytes.Equal(csum, entries[i].Entry.Payload) {
+				t.Errorf("checksum %q: expected %v; got %v",
+					entries[i].Entry.Name,
+					entries[i].Entry.Payload,
+					csum)
+			}
+		}
+	}
+
+	for _, e := range entriesMangled {
+		if e.Entry.Type == storage.FileType {
+			rdr, err := fgp.Get(e.Entry.Name)
+			if err != nil {
+				t.Error(err)
+			}
+			c := crc64.New(storage.CRCTable)
+			i, err := io.Copy(c, rdr)
+			if err != nil {
+				t.Fatal(err)
+			}
+			rdr.Close()
+
+			csum := c.Sum(nil)
+			if bytes.Equal(csum, e.Entry.Payload) {
+				t.Errorf("wrote %d bytes. checksum for %q should not have matched! %v",
+					i,
+					e.Entry.Name,
+					csum)
+			}
+		}
+	}
+}
+
+func TestTarStream(t *testing.T) {
+	var (
+		expectedSum        = "1eb237ff69bca6e22789ecb05b45d35ca307adbd"
+		expectedSize int64 = 10240
+	)
+
+	fh, err := os.Open("./testdata/t.tar.gz")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer fh.Close()
+	gzRdr, err := gzip.NewReader(fh)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer gzRdr.Close()
+
+	// Setup where we'll store the metadata
+	w := bytes.NewBuffer([]byte{})
+	sp := storage.NewJSONPacker(w)
+	fgp := storage.NewBufferFileGetPutter()
+
+	// wrap the disassembly stream
+	tarStream, err := NewInputTarStream(gzRdr, sp, fgp)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// get a sum of the stream after it has passed through to ensure it's the same.
+	h0 := sha1.New()
+	tRdr0 := io.TeeReader(tarStream, h0)
+
+	// read it all to the bit bucket
+	i, err := io.Copy(ioutil.Discard, tRdr0)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if i != expectedSize {
+		t.Errorf("size of tar: expected %d; got %d", expectedSize, i)
+	}
+	if fmt.Sprintf("%x", h0.Sum(nil)) != expectedSum {
+		t.Fatalf("checksum of tar: expected %s; got %x", expectedSum, h0.Sum(nil))
+	}
+
+	t.Logf("%s", w.String()) // if we fail, then show the packed info
+
+	// If we've made it this far, then we'll turn it around and create a tar
+	// stream from the packed metadata and buffered file contents.
+	r := bytes.NewBuffer(w.Bytes())
+	sup := storage.NewJSONUnpacker(r)
+	// and reuse the fgp that we Put the payloads to.
+
+	rc := NewOutputTarStream(fgp, sup)
+	h1 := sha1.New()
+	i, err = io.Copy(h1, rc)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if i != expectedSize {
+		t.Errorf("size of output tar: expected %d; got %d", expectedSize, i)
+	}
+	if fmt.Sprintf("%x", h1.Sum(nil)) != expectedSum {
+		t.Fatalf("checksum of output tar: expected %s; got %x", expectedSum, h1.Sum(nil))
+	}
+}

vendor/src/github.com/vbatts/tar-split/tar/asm/disassemble.go

@@ -0,0 +1,133 @@
+package asm
+
+import (
+	"io"
+	"io/ioutil"
+
+	"github.com/vbatts/tar-split/archive/tar"
+	"github.com/vbatts/tar-split/tar/storage"
+)
+
+// NewInputTarStream wraps the Reader stream of a tar archive and provides a
+// Reader stream of the same.
+//
+// In the middle it will pack the segments and file metadata to storage.Packer
+// `p`.
+//
+// The the storage.FilePutter is where payload of files in the stream are
+// stashed. If this stashing is not needed, you can provide a nil
+// storage.FilePutter. Since the checksumming is still needed, then a default
+// of NewDiscardFilePutter will be used internally
+func NewInputTarStream(r io.Reader, p storage.Packer, fp storage.FilePutter) (io.Reader, error) {
+	// What to do here... folks will want their own access to the Reader that is
+	// their tar archive stream, but we'll need that same stream to use our
+	// forked 'archive/tar'.
+	// Perhaps do an io.TeeReader that hand back an io.Reader for them to read
+	// from, and we'll mitm the stream to store metadata.
+	// We'll need a storage.FilePutter too ...
+
+	// Another concern, whether to do any storage.FilePutter operations, such that we
+	// don't extract any amount of the archive. But then again, we're not making
+	// files/directories, hardlinks, etc. Just writing the io to the storage.FilePutter.
+	// Perhaps we have a DiscardFilePutter that is a bit bucket.
+
+	// we'll return the pipe reader, since TeeReader does not buffer and will
+	// only read what the outputRdr Read's. Since Tar archive's have padding on
+	// the end, we want to be the one reading the padding, even if the user's
+	// `archive/tar` doesn't care.
+	pR, pW := io.Pipe()
+	outputRdr := io.TeeReader(r, pW)
+
+	// we need a putter that will generate the crc64 sums of file payloads
+	if fp == nil {
+		fp = storage.NewDiscardFilePutter()
+	}
+
+	go func() {
+		tr := tar.NewReader(outputRdr)
+		tr.RawAccounting = true
+		for {
+			hdr, err := tr.Next()
+			if err != nil {
+				if err != io.EOF {
+					pW.CloseWithError(err)
+					return
+				}
+				// even when an EOF is reached, there is often 1024 null bytes on
+				// the end of an archive. Collect them too.
+				_, err := p.AddEntry(storage.Entry{
+					Type:    storage.SegmentType,
+					Payload: tr.RawBytes(),
+				})
+				if err != nil {
+					pW.CloseWithError(err)
+					return
+				}
+				break // not return. We need the end of the reader.
+			}
+			if hdr == nil {
+				break // not return. We need the end of the reader.
+			}
+
+			if _, err := p.AddEntry(storage.Entry{
+				Type:    storage.SegmentType,
+				Payload: tr.RawBytes(),
+			}); err != nil {
+				pW.CloseWithError(err)
+				return
+			}
+
+			var csum []byte
+			if hdr.Size > 0 {
+				var err error
+				_, csum, err = fp.Put(hdr.Name, tr)
+				if err != nil {
+					pW.CloseWithError(err)
+					return
+				}
+			}
+
+			// File entries added, regardless of size
+			_, err = p.AddEntry(storage.Entry{
+				Type:    storage.FileType,
+				Name:    hdr.Name,
+				Size:    hdr.Size,
+				Payload: csum,
+			})
+			if err != nil {
+				pW.CloseWithError(err)
+				return
+			}
+
+			if b := tr.RawBytes(); len(b) > 0 {
+				_, err = p.AddEntry(storage.Entry{
+					Type:    storage.SegmentType,
+					Payload: b,
+				})
+				if err != nil {
+					pW.CloseWithError(err)
+					return
+				}
+			}
+		}
+
+		// it is allowable, and not uncommon that there is further padding on the
+		// end of an archive, apart from the expected 1024 null bytes.
+		remainder, err := ioutil.ReadAll(outputRdr)
+		if err != nil && err != io.EOF {
+			pW.CloseWithError(err)
+			return
+		}
+		_, err = p.AddEntry(storage.Entry{
+			Type:    storage.SegmentType,
+			Payload: remainder,
+		})
+		if err != nil {
+			pW.CloseWithError(err)
+			return
+		}
+		pW.Close()
+	}()
+
+	return pR, nil
+}

vendor/src/github.com/vbatts/tar-split/tar/asm/doc.go

@@ -0,0 +1,9 @@
+/*
+Package asm provides the API for streaming assembly and disassembly of tar
+archives.
+
+Using the `github.com/vbatts/tar-split/tar/storage` for Packing/Unpacking the
+metadata for a stream, as well as an implementation of Getting/Putting the file
+entries' payload.
+*/
+package asm

vendor/src/github.com/vbatts/tar-split/tar/storage/doc.go

@@ -0,0 +1,12 @@
+/*
+Package storage is for metadata of a tar archive.
+
+Packing and unpacking the Entries of the stream. The types of streams are
+either segments of raw bytes (for the raw headers and various padding) and for
+an entry marking a file payload.
+
+The raw bytes are stored precisely in the packed (marshalled) Entry. Where as
+the file payload marker include the name of the file, size, and crc64 checksum
+(for basic file integrity).
+*/
+package storage

vendor/src/github.com/vbatts/tar-split/tar/storage/entry.go

@@ -0,0 +1,39 @@
+package storage
+
+// Entries is for sorting by Position
+type Entries []Entry
+
+func (e Entries) Len() int           { return len(e) }
+func (e Entries) Swap(i, j int)      { e[i], e[j] = e[j], e[i] }
+func (e Entries) Less(i, j int) bool { return e[i].Position < e[j].Position }
+
+// Type of Entry
+type Type int
+
+const (
+	// FileType represents a file payload from the tar stream.
+	//
+	// This will be used to map to relative paths on disk. Only Size > 0 will get
+	// read into a resulting output stream (due to hardlinks).
+	FileType Type = 1 + iota
+	// SegmentType represents a raw bytes segment from the archive stream. These raw
+	// byte segments consist of the raw headers and various padding.
+	//
+	// It's payload is to be marshalled base64 encoded.
+	SegmentType
+)
+
+// Entry is a the structure for packing and unpacking the information read from
+// the Tar archive.
+//
+// FileType Payload checksum is using `hash/crc64` for basic file integrity,
+// _not_ for cryptography.
+// From http://www.backplane.com/matt/crc64.html, CRC32 has almost 40,000
+// collisions in a sample of 18.2 million, CRC64 had none.
+type Entry struct {
+	Type     Type   `json:"type"`
+	Name     string `json:"name",omitempty`
+	Size     int64  `json:"size",omitempty`
+	Payload  []byte `json:"payload"` // SegmentType store payload here; FileType store crc64 checksum here;
+	Position int    `json:"position"`
+}

vendor/src/github.com/vbatts/tar-split/tar/storage/entry_test.go

@@ -0,0 +1,66 @@
+package storage
+
+import (
+	"encoding/json"
+	"sort"
+	"testing"
+)
+
+func TestEntries(t *testing.T) {
+	e := Entries{
+		Entry{
+			Type:     SegmentType,
+			Payload:  []byte("y'all"),
+			Position: 1,
+		},
+		Entry{
+			Type:     SegmentType,
+			Payload:  []byte("doin"),
+			Position: 3,
+		},
+		Entry{
+			Type:     FileType,
+			Name:     "./hurr.txt",
+			Payload:  []byte("deadbeef"),
+			Position: 2,
+		},
+		Entry{
+			Type:     SegmentType,
+			Payload:  []byte("how"),
+			Position: 0,
+		},
+	}
+	sort.Sort(e)
+	if e[0].Position != 0 {
+		t.Errorf("expected Position 0, but got %d", e[0].Position)
+	}
+}
+
+func TestFile(t *testing.T) {
+	f := Entry{
+		Type:     FileType,
+		Name:     "./hello.txt",
+		Size:     100,
+		Position: 2,
+	}
+
+	buf, err := json.Marshal(f)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	f1 := Entry{}
+	if err = json.Unmarshal(buf, &f1); err != nil {
+		t.Fatal(err)
+	}
+
+	if f.Name != f1.Name {
+		t.Errorf("expected Name %q, got %q", f.Name, f1.Name)
+	}
+	if f.Size != f1.Size {
+		t.Errorf("expected Size %q, got %q", f.Size, f1.Size)
+	}
+	if f.Position != f1.Position {
+		t.Errorf("expected Position %q, got %q", f.Position, f1.Position)
+	}
+}

vendor/src/github.com/vbatts/tar-split/tar/storage/getter.go

@@ -0,0 +1,106 @@
+package storage
+
+import (
+	"bytes"
+	"errors"
+	"hash/crc64"
+	"io"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+)
+
+// FileGetter is the interface for getting a stream of a file payload, address
+// by name/filename. Presumably, the names will be scoped to relative file
+// paths.
+type FileGetter interface {
+	// Get returns a stream for the provided file path
+	Get(filename string) (output io.ReadCloser, err error)
+}
+
+// FilePutter is the interface for storing a stream of a file payload,
+// addressed by name/filename.
+type FilePutter interface {
+	// Put returns the size of the stream received, and the crc64 checksum for
+	// the provided stream
+	Put(filename string, input io.Reader) (size int64, checksum []byte, err error)
+}
+
+// FileGetPutter is the interface that groups both Getting and Putting file
+// payloads.
+type FileGetPutter interface {
+	FileGetter
+	FilePutter
+}
+
+// NewPathFileGetter returns a FileGetter that is for files relative to path
+// relpath.
+func NewPathFileGetter(relpath string) FileGetter {
+	return &pathFileGetter{root: relpath}
+}
+
+type pathFileGetter struct {
+	root string
+}
+
+func (pfg pathFileGetter) Get(filename string) (io.ReadCloser, error) {
+	return os.Open(filepath.Join(pfg.root, filename))
+}
+
+type bufferFileGetPutter struct {
+	files map[string][]byte
+}
+
+func (bfgp bufferFileGetPutter) Get(name string) (io.ReadCloser, error) {
+	if _, ok := bfgp.files[name]; !ok {
+		return nil, errors.New("no such file")
+	}
+	b := bytes.NewBuffer(bfgp.files[name])
+	return &readCloserWrapper{b}, nil
+}
+
+func (bfgp *bufferFileGetPutter) Put(name string, r io.Reader) (int64, []byte, error) {
+	c := crc64.New(CRCTable)
+	tRdr := io.TeeReader(r, c)
+	b := bytes.NewBuffer([]byte{})
+	i, err := io.Copy(b, tRdr)
+	if err != nil {
+		return 0, nil, err
+	}
+	bfgp.files[name] = b.Bytes()
+	return i, c.Sum(nil), nil
+}
+
+type readCloserWrapper struct {
+	io.Reader
+}
+
+func (w *readCloserWrapper) Close() error { return nil }
+
+// NewBufferFileGetPutter is simple in memory FileGetPutter
+//
+// Implication is this is memory intensive...
+// Probably best for testing or light weight cases.
+func NewBufferFileGetPutter() FileGetPutter {
+	return &bufferFileGetPutter{
+		files: map[string][]byte{},
+	}
+}
+
+// NewDiscardFilePutter is a bit bucket FilePutter
+func NewDiscardFilePutter() FilePutter {
+	return &bitBucketFilePutter{}
+}
+
+type bitBucketFilePutter struct {
+}
+
+func (bbfp *bitBucketFilePutter) Put(name string, r io.Reader) (int64, []byte, error) {
+	c := crc64.New(CRCTable)
+	tRdr := io.TeeReader(r, c)
+	i, err := io.Copy(ioutil.Discard, tRdr)
+	return i, c.Sum(nil), err
+}
+
+// CRCTable is the default table used for crc64 sum calculations
+var CRCTable = crc64.MakeTable(crc64.ISO)

vendor/src/github.com/vbatts/tar-split/tar/storage/getter_test.go

@@ -0,0 +1,62 @@
+package storage
+
+import (
+	"bytes"
+	"io/ioutil"
+	"testing"
+)
+
+func TestGetter(t *testing.T) {
+	fgp := NewBufferFileGetPutter()
+	files := map[string]map[string][]byte{
+		"file1.txt": {"foo": []byte{60, 60, 48, 48, 0, 0, 0, 0}},
+		"file2.txt": {"bar": []byte{45, 196, 22, 240, 0, 0, 0, 0}},
+	}
+	for n, b := range files {
+		for body, sum := range b {
+			_, csum, err := fgp.Put(n, bytes.NewBufferString(body))
+			if err != nil {
+				t.Error(err)
+			}
+			if !bytes.Equal(csum, sum) {
+				t.Errorf("checksum: expected 0x%x; got 0x%x", sum, csum)
+			}
+		}
+	}
+	for n, b := range files {
+		for body := range b {
+			r, err := fgp.Get(n)
+			if err != nil {
+				t.Error(err)
+			}
+			buf, err := ioutil.ReadAll(r)
+			if err != nil {
+				t.Error(err)
+			}
+			if body != string(buf) {
+				t.Errorf("expected %q, got %q", body, string(buf))
+			}
+		}
+	}
+}
+func TestPutter(t *testing.T) {
+	fp := NewDiscardFilePutter()
+	// map[filename]map[body]crc64sum
+	files := map[string]map[string][]byte{
+		"file1.txt": {"foo": []byte{60, 60, 48, 48, 0, 0, 0, 0}},
+		"file2.txt": {"bar": []byte{45, 196, 22, 240, 0, 0, 0, 0}},
+		"file3.txt": {"baz": []byte{32, 68, 22, 240, 0, 0, 0, 0}},
+		"file4.txt": {"bif": []byte{48, 9, 150, 240, 0, 0, 0, 0}},
+	}
+	for n, b := range files {
+		for body, sum := range b {
+			_, csum, err := fp.Put(n, bytes.NewBufferString(body))
+			if err != nil {
+				t.Error(err)
+			}
+			if !bytes.Equal(csum, sum) {
+				t.Errorf("checksum on %q: expected %v; got %v", n, sum, csum)
+			}
+		}
+	}
+}

vendor/src/github.com/vbatts/tar-split/tar/storage/packer.go

@@ -0,0 +1,140 @@
+package storage
+
+import (
+	"bufio"
+	"encoding/json"
+	"errors"
+	"io"
+	"path/filepath"
+)
+
+// ErrDuplicatePath is occured when a tar archive has more than one entry for
+// the same file path
+var ErrDuplicatePath = errors.New("duplicates of file paths not supported")
+
+// Packer describes the methods to pack Entries to a storage destination
+type Packer interface {
+	// AddEntry packs the Entry and returns its position
+	AddEntry(e Entry) (int, error)
+}
+
+// Unpacker describes the methods to read Entries from a source
+type Unpacker interface {
+	// Next returns the next Entry being unpacked, or error, until io.EOF
+	Next() (*Entry, error)
+}
+
+/* TODO(vbatts) figure out a good model for this
+type PackUnpacker interface {
+	Packer
+	Unpacker
+}
+*/
+
+type jsonUnpacker struct {
+	r     io.Reader
+	b     *bufio.Reader
+	isEOF bool
+	seen  seenNames
+}
+
+func (jup *jsonUnpacker) Next() (*Entry, error) {
+	var e Entry
+	if jup.isEOF {
+		// since ReadBytes() will return read bytes AND an EOF, we handle it this
+		// round-a-bout way so we can Unmarshal the tail with relevant errors, but
+		// still get an io.EOF when the stream is ended.
+		return nil, io.EOF
+	}
+	line, err := jup.b.ReadBytes('\n')
+	if err != nil && err != io.EOF {
+		return nil, err
+	} else if err == io.EOF {
+		jup.isEOF = true
+	}
+
+	err = json.Unmarshal(line, &e)
+	if err != nil && jup.isEOF {
+		// if the remainder actually _wasn't_ a remaining json structure, then just EOF
+		return nil, io.EOF
+	}
+
+	// check for dup name
+	if e.Type == FileType {
+		cName := filepath.Clean(e.Name)
+		if _, ok := jup.seen[cName]; ok {
+			return nil, ErrDuplicatePath
+		}
+		jup.seen[cName] = emptyByte
+	}
+
+	return &e, err
+}
+
+// NewJSONUnpacker provides an Unpacker that reads Entries (SegmentType and
+// FileType) as a json document.
+//
+// Each Entry read are expected to be delimited by new line.
+func NewJSONUnpacker(r io.Reader) Unpacker {
+	return &jsonUnpacker{
+		r:    r,
+		b:    bufio.NewReader(r),
+		seen: seenNames{},
+	}
+}
+
+type jsonPacker struct {
+	w    io.Writer
+	e    *json.Encoder
+	pos  int
+	seen seenNames
+}
+
+type seenNames map[string]byte
+
+// used in the seenNames map. byte is a uint8, and we'll re-use the same one
+// for minimalism.
+const emptyByte byte = 0
+
+func (jp *jsonPacker) AddEntry(e Entry) (int, error) {
+	// check early for dup name
+	if e.Type == FileType {
+		cName := filepath.Clean(e.Name)
+		if _, ok := jp.seen[cName]; ok {
+			return -1, ErrDuplicatePath
+		}
+		jp.seen[cName] = emptyByte
+	}
+
+	e.Position = jp.pos
+	err := jp.e.Encode(e)
+	if err != nil {
+		return -1, err
+	}
+
+	// made it this far, increment now
+	jp.pos++
+	return e.Position, nil
+}
+
+// NewJSONPacker provides an Packer that writes each Entry (SegmentType and
+// FileType) as a json document.
+//
+// The Entries are delimited by new line.
+func NewJSONPacker(w io.Writer) Packer {
+	return &jsonPacker{
+		w:    w,
+		e:    json.NewEncoder(w),
+		seen: seenNames{},
+	}
+}
+
+/*
+TODO(vbatts) perhaps have a more compact packer/unpacker, maybe using msgapck
+(https://github.com/ugorji/go)
+
+
+Even though, since our jsonUnpacker and jsonPacker just take
+io.Reader/io.Writer, then we can get away with passing them a
+gzip.Reader/gzip.Writer
+*/

vendor/src/github.com/vbatts/tar-split/tar/storage/packer_test.go

@@ -0,0 +1,163 @@
+package storage
+
+import (
+	"bytes"
+	"compress/gzip"
+	"io"
+	"testing"
+)
+
+func TestDuplicateFail(t *testing.T) {
+	e := []Entry{
+		Entry{
+			Type:    FileType,
+			Name:    "./hurr.txt",
+			Payload: []byte("abcde"),
+		},
+		Entry{
+			Type:    FileType,
+			Name:    "./hurr.txt",
+			Payload: []byte("deadbeef"),
+		},
+		Entry{
+			Type:    FileType,
+			Name:    "hurr.txt", // slightly different path, same file though
+			Payload: []byte("deadbeef"),
+		},
+	}
+	buf := []byte{}
+	b := bytes.NewBuffer(buf)
+
+	jp := NewJSONPacker(b)
+	if _, err := jp.AddEntry(e[0]); err != nil {
+		t.Error(err)
+	}
+	if _, err := jp.AddEntry(e[1]); err != ErrDuplicatePath {
+		t.Errorf("expected failure on duplicate path")
+	}
+	if _, err := jp.AddEntry(e[2]); err != ErrDuplicatePath {
+		t.Errorf("expected failure on duplicate path")
+	}
+}
+
+func TestJSONPackerUnpacker(t *testing.T) {
+	e := []Entry{
+		Entry{
+			Type:    SegmentType,
+			Payload: []byte("how"),
+		},
+		Entry{
+			Type:    SegmentType,
+			Payload: []byte("y'all"),
+		},
+		Entry{
+			Type:    FileType,
+			Name:    "./hurr.txt",
+			Payload: []byte("deadbeef"),
+		},
+		Entry{
+			Type:    SegmentType,
+			Payload: []byte("doin"),
+		},
+	}
+
+	buf := []byte{}
+	b := bytes.NewBuffer(buf)
+
+	func() {
+		jp := NewJSONPacker(b)
+		for i := range e {
+			if _, err := jp.AddEntry(e[i]); err != nil {
+				t.Error(err)
+			}
+		}
+	}()
+
+	// >> packer_test.go:43: uncompressed: 266
+	//t.Errorf("uncompressed: %d", len(b.Bytes()))
+
+	b = bytes.NewBuffer(b.Bytes())
+	entries := Entries{}
+	func() {
+		jup := NewJSONUnpacker(b)
+		for {
+			entry, err := jup.Next()
+			if err != nil {
+				if err == io.EOF {
+					break
+				}
+				t.Error(err)
+			}
+			entries = append(entries, *entry)
+			t.Logf("got %#v", entry)
+		}
+	}()
+	if len(entries) != len(e) {
+		t.Errorf("expected %d entries, got %d", len(e), len(entries))
+	}
+}
+
+// you can use a compress Reader/Writer and make nice savings.
+//
+// For these two tests that are using the same set, it the difference of 266
+// bytes uncompressed vs 138 bytes compressed.
+func TestGzip(t *testing.T) {
+	e := []Entry{
+		Entry{
+			Type:    SegmentType,
+			Payload: []byte("how"),
+		},
+		Entry{
+			Type:    SegmentType,
+			Payload: []byte("y'all"),
+		},
+		Entry{
+			Type:    FileType,
+			Name:    "./hurr.txt",
+			Payload: []byte("deadbeef"),
+		},
+		Entry{
+			Type:    SegmentType,
+			Payload: []byte("doin"),
+		},
+	}
+
+	buf := []byte{}
+	b := bytes.NewBuffer(buf)
+	gzW := gzip.NewWriter(b)
+	jp := NewJSONPacker(gzW)
+	for i := range e {
+		if _, err := jp.AddEntry(e[i]); err != nil {
+			t.Error(err)
+		}
+	}
+	gzW.Close()
+
+	// >> packer_test.go:99: compressed: 138
+	//t.Errorf("compressed: %d", len(b.Bytes()))
+
+	b = bytes.NewBuffer(b.Bytes())
+	gzR, err := gzip.NewReader(b)
+	if err != nil {
+		t.Fatal(err)
+	}
+	entries := Entries{}
+	func() {
+		jup := NewJSONUnpacker(gzR)
+		for {
+			entry, err := jup.Next()
+			if err != nil {
+				if err == io.EOF {
+					break
+				}
+				t.Error(err)
+			}
+			entries = append(entries, *entry)
+			t.Logf("got %#v", entry)
+		}
+	}()
+	if len(entries) != len(e) {
+		t.Errorf("expected %d entries, got %d", len(e), len(entries))
+	}
+
+}