vendor

go.mod

@@ -0,0 +1,7 @@
+module novit.nc/direktil/inits
+
+require (
+	github.com/sparrc/go-ping v0.0.0-20160208162908-416e72114cd1
+	golang.org/x/net v0.0.0-20180706051357-32a936f46389
+	novit.nc/direktil/pkg v0.0.0-20180703072055-a44d1cbe7fbb
+)

vendor/github.com/sparrc/go-ping/.gitignore

@@ -0,0 +1 @@
+/ping

vendor/github.com/sparrc/go-ping/LICENSE

@@ -0,0 +1,21 @@
+The MIT License (MIT)
+
+Copyright (c) 2016 Cameron Sparr
+
+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/github.com/sparrc/go-ping/README.md

@@ -0,0 +1,82 @@
+# go-ping
+[![GoDoc](https://godoc.org/github.com/sparrc/go-ping?status.svg)](https://godoc.org/github.com/sparrc/go-ping)
+[![Circle CI](https://circleci.com/gh/sparrc/go-ping.svg?style=svg)](https://circleci.com/gh/sparrc/go-ping)
+
+ICMP Ping library for Go, inspired by
+[go-fastping](https://github.com/tatsushid/go-fastping)
+
+Here is a very simple example that sends & receives 3 packets:
+
+```go
+pinger, err := ping.NewPinger("www.google.com")
+if err != nil {
+        panic(err)
+}
+pinger.Count = 3
+pinger.Run() // blocks until finished
+stats := pinger.Statistics() // get send/receive/rtt stats
+```
+
+Here is an example that emulates the unix ping command:
+
+```go
+pinger, err := ping.NewPinger("www.google.com")
+if err != nil {
+        panic(err)
+}
+
+pinger.OnRecv = func(pkt *ping.Packet) {
+        fmt.Printf("%d bytes from %s: icmp_seq=%d time=%v\n",
+                pkt.Nbytes, pkt.IPAddr, pkt.Seq, pkt.Rtt)
+}
+pinger.OnFinish = func(stats *ping.Statistics) {
+        fmt.Printf("\n--- %s ping statistics ---\n", stats.Addr)
+        fmt.Printf("%d packets transmitted, %d packets received, %v%% packet loss\n",
+                stats.PacketsSent, stats.PacketsRecv, stats.PacketLoss)
+        fmt.Printf("round-trip min/avg/max/stddev = %v/%v/%v/%v\n",
+                stats.MinRtt, stats.AvgRtt, stats.MaxRtt, stats.StdDevRtt)
+}
+
+fmt.Printf("PING %s (%s):\n", pinger.Addr(), pinger.IPAddr())
+pinger.Run()
+```
+
+It sends ICMP packet(s) and waits for a response. If it receives a response,
+it calls the "receive" callback. When it's finished, it calls the "finish"
+callback.
+
+For a full ping example, see
+[cmd/ping/ping.go](https://github.com/sparrc/go-ping/blob/master/cmd/ping/ping.go)
+
+## Installation:
+
+```
+go get github.com/sparrc/go-ping
+```
+
+To install the native Go ping executable:
+
+```bash
+go get github.com/sparrc/go-ping/...
+$GOPATH/bin/ping
+```
+
+## Note on Linux Support:
+
+This library attempts to send an
+"unprivileged" ping via UDP. On linux, this must be enabled by setting
+
+```
+sudo sysctl -w net.ipv4.ping_group_range="0   2147483647"
+```
+
+If you do not wish to do this, you can set `pinger.SetPrivileged(true)` and
+use setcap to allow your binary using go-ping to bind to raw sockets
+(or just run as super-user):
+
+```
+setcap cap_net_raw=+ep /bin/goping-binary
+```
+
+See [this blog](https://sturmflut.github.io/linux/ubuntu/2015/01/17/unprivileged-icmp-sockets-on-linux/)
+and [the Go icmp library](https://godoc.org/golang.org/x/net/icmp) for more details.

vendor/github.com/sparrc/go-ping/circle.yml

@@ -0,0 +1,9 @@
+test:
+  post:
+    - go build -race -o ping_linux ./cmd/ping/ping.go
+    - sudo ./ping_linux --privileged -c 2 www.google.com
+    - sudo ./ping_linux --privileged -c 3 -i 200ms www.google.com
+    - sudo ./ping_linux --privileged -c 10 -i 100ms -t 1s www.google.com
+    - GOOS=darwin go build -o ping_darwin ./cmd/ping/ping.go
+    - mv ping_linux $CIRCLE_ARTIFACTS
+    - mv ping_darwin $CIRCLE_ARTIFACTS

vendor/github.com/sparrc/go-ping/ping.go

@@ -0,0 +1,549 @@
+// Package ping is an ICMP ping library seeking to emulate the unix "ping"
+// command.
+//
+// Here is a very simple example that sends & receives 3 packets:
+//
+//	pinger, err := ping.NewPinger("www.google.com")
+//	if err != nil {
+//		panic(err)
+//	}
+//
+//	pinger.Count = 3
+//	pinger.Run() // blocks until finished
+//	stats := pinger.Statistics() // get send/receive/rtt stats
+//
+// Here is an example that emulates the unix ping command:
+//
+//	pinger, err := ping.NewPinger("www.google.com")
+//	if err != nil {
+//		fmt.Printf("ERROR: %s\n", err.Error())
+//		return
+//	}
+//
+//	pinger.OnRecv = func(pkt *ping.Packet) {
+//		fmt.Printf("%d bytes from %s: icmp_seq=%d time=%v\n",
+//			pkt.Nbytes, pkt.IPAddr, pkt.Seq, pkt.Rtt)
+//	}
+//	pinger.OnFinish = func(stats *ping.Statistics) {
+//		fmt.Printf("\n--- %s ping statistics ---\n", stats.Addr)
+//		fmt.Printf("%d packets transmitted, %d packets received, %v%% packet loss\n",
+//			stats.PacketsSent, stats.PacketsRecv, stats.PacketLoss)
+//		fmt.Printf("round-trip min/avg/max/stddev = %v/%v/%v/%v\n",
+//			stats.MinRtt, stats.AvgRtt, stats.MaxRtt, stats.StdDevRtt)
+//	}
+//
+//	fmt.Printf("PING %s (%s):\n", pinger.Addr(), pinger.IPAddr())
+//	pinger.Run()
+//
+// It sends ICMP packet(s) and waits for a response. If it receives a response,
+// it calls the "receive" callback. When it's finished, it calls the "finish"
+// callback.
+//
+// For a full ping example, see "cmd/ping/ping.go".
+//
+package ping
+
+import (
+	"fmt"
+	"math"
+	"math/rand"
+	"net"
+	"os"
+	"os/signal"
+	"sync"
+	"syscall"
+	"time"
+
+	"golang.org/x/net/icmp"
+	"golang.org/x/net/ipv4"
+	"golang.org/x/net/ipv6"
+)
+
+const (
+	timeSliceLength  = 8
+	protocolICMP     = 1
+	protocolIPv6ICMP = 58
+)
+
+var (
+	ipv4Proto = map[string]string{"ip": "ip4:icmp", "udp": "udp4"}
+	ipv6Proto = map[string]string{"ip": "ip6:ipv6-icmp", "udp": "udp6"}
+)
+
+// NewPinger returns a new Pinger struct pointer
+func NewPinger(addr string) (*Pinger, error) {
+	ipaddr, err := net.ResolveIPAddr("ip", addr)
+	if err != nil {
+		return nil, err
+	}
+
+	var ipv4 bool
+	if isIPv4(ipaddr.IP) {
+		ipv4 = true
+	} else if isIPv6(ipaddr.IP) {
+		ipv4 = false
+	}
+
+	return &Pinger{
+		ipaddr:   ipaddr,
+		addr:     addr,
+		Interval: time.Second,
+		Timeout:  time.Second * 100000,
+		Count:    -1,
+
+		network: "udp",
+		ipv4:    ipv4,
+		size:    timeSliceLength,
+
+		done: make(chan bool),
+	}, nil
+}
+
+// Pinger represents ICMP packet sender/receiver
+type Pinger struct {
+	// Interval is the wait time between each packet send. Default is 1s.
+	Interval time.Duration
+
+	// Timeout specifies a timeout before ping exits, regardless of how many
+	// packets have been received.
+	Timeout time.Duration
+
+	// Count tells pinger to stop after sending (and receiving) Count echo
+	// packets. If this option is not specified, pinger will operate until
+	// interrupted.
+	Count int
+
+	// Debug runs in debug mode
+	Debug bool
+
+	// Number of packets sent
+	PacketsSent int
+
+	// Number of packets received
+	PacketsRecv int
+
+	// rtts is all of the Rtts
+	rtts []time.Duration
+
+	// OnRecv is called when Pinger receives and processes a packet
+	OnRecv func(*Packet)
+
+	// OnFinish is called when Pinger exits
+	OnFinish func(*Statistics)
+
+	// stop chan bool
+	done chan bool
+
+	ipaddr *net.IPAddr
+	addr   string
+
+	ipv4     bool
+	source   string
+	size     int
+	sequence int
+	network  string
+}
+
+type packet struct {
+	bytes  []byte
+	nbytes int
+}
+
+// Packet represents a received and processed ICMP echo packet.
+type Packet struct {
+	// Rtt is the round-trip time it took to ping.
+	Rtt time.Duration
+
+	// IPAddr is the address of the host being pinged.
+	IPAddr *net.IPAddr
+
+	// NBytes is the number of bytes in the message.
+	Nbytes int
+
+	// Seq is the ICMP sequence number.
+	Seq int
+}
+
+// Statistics represent the stats of a currently running or finished
+// pinger operation.
+type Statistics struct {
+	// PacketsRecv is the number of packets received.
+	PacketsRecv int
+
+	// PacketsSent is the number of packets sent.
+	PacketsSent int
+
+	// PacketLoss is the percentage of packets lost.
+	PacketLoss float64
+
+	// IPAddr is the address of the host being pinged.
+	IPAddr *net.IPAddr
+
+	// Addr is the string address of the host being pinged.
+	Addr string
+
+	// Rtts is all of the round-trip times sent via this pinger.
+	Rtts []time.Duration
+
+	// MinRtt is the minimum round-trip time sent via this pinger.
+	MinRtt time.Duration
+
+	// MaxRtt is the maximum round-trip time sent via this pinger.
+	MaxRtt time.Duration
+
+	// AvgRtt is the average round-trip time sent via this pinger.
+	AvgRtt time.Duration
+
+	// StdDevRtt is the standard deviation of the round-trip times sent via
+	// this pinger.
+	StdDevRtt time.Duration
+}
+
+// SetIPAddr sets the ip address of the target host.
+func (p *Pinger) SetIPAddr(ipaddr *net.IPAddr) {
+	var ipv4 bool
+	if isIPv4(ipaddr.IP) {
+		ipv4 = true
+	} else if isIPv6(ipaddr.IP) {
+		ipv4 = false
+	}
+
+	p.ipaddr = ipaddr
+	p.addr = ipaddr.String()
+	p.ipv4 = ipv4
+}
+
+// IPAddr returns the ip address of the target host.
+func (p *Pinger) IPAddr() *net.IPAddr {
+	return p.ipaddr
+}
+
+// SetAddr resolves and sets the ip address of the target host, addr can be a
+// DNS name like "www.google.com" or IP like "127.0.0.1".
+func (p *Pinger) SetAddr(addr string) error {
+	ipaddr, err := net.ResolveIPAddr("ip", addr)
+	if err != nil {
+		return err
+	}
+
+	p.SetIPAddr(ipaddr)
+	p.addr = addr
+	return nil
+}
+
+// Addr returns the string ip address of the target host.
+func (p *Pinger) Addr() string {
+	return p.addr
+}
+
+// SetPrivileged sets the type of ping pinger will send.
+// false means pinger will send an "unprivileged" UDP ping.
+// true means pinger will send a "privileged" raw ICMP ping.
+// NOTE: setting to true requires that it be run with super-user privileges.
+func (p *Pinger) SetPrivileged(privileged bool) {
+	if privileged {
+		p.network = "ip"
+	} else {
+		p.network = "udp"
+	}
+}
+
+// Privileged returns whether pinger is running in privileged mode.
+func (p *Pinger) Privileged() bool {
+	return p.network == "ip"
+}
+
+// Run runs the pinger. This is a blocking function that will exit when it's
+// done. If Count or Interval are not specified, it will run continuously until
+// it is interrupted.
+func (p *Pinger) Run() {
+	p.run()
+}
+
+func (p *Pinger) run() {
+	var conn *icmp.PacketConn
+	if p.ipv4 {
+		if conn = p.listen(ipv4Proto[p.network], p.source); conn == nil {
+			return
+		}
+	} else {
+		if conn = p.listen(ipv6Proto[p.network], p.source); conn == nil {
+			return
+		}
+	}
+	defer conn.Close()
+	defer p.finish()
+
+	var wg sync.WaitGroup
+	recv := make(chan *packet, 5)
+	wg.Add(1)
+	go p.recvICMP(conn, recv, &wg)
+
+	err := p.sendICMP(conn)
+	if err != nil {
+		fmt.Println(err.Error())
+	}
+
+	timeout := time.NewTicker(p.Timeout)
+	interval := time.NewTicker(p.Interval)
+	c := make(chan os.Signal, 1)
+	signal.Notify(c, os.Interrupt)
+	signal.Notify(c, syscall.SIGTERM)
+
+	for {
+		select {
+		case <-c:
+			close(p.done)
+		case <-p.done:
+			wg.Wait()
+			return
+		case <-timeout.C:
+			close(p.done)
+			wg.Wait()
+			return
+		case <-interval.C:
+			err = p.sendICMP(conn)
+			if err != nil {
+				fmt.Println("FATAL: ", err.Error())
+			}
+		case r := <-recv:
+			err := p.processPacket(r)
+			if err != nil {
+				fmt.Println("FATAL: ", err.Error())
+			}
+		default:
+			if p.Count > 0 && p.PacketsRecv >= p.Count {
+				close(p.done)
+				wg.Wait()
+				return
+			}
+		}
+	}
+}
+
+func (p *Pinger) finish() {
+	handler := p.OnFinish
+	if handler != nil {
+		s := p.Statistics()
+		handler(s)
+	}
+}
+
+// Statistics returns the statistics of the pinger. This can be run while the
+// pinger is running or after it is finished. OnFinish calls this function to
+// get it's finished statistics.
+func (p *Pinger) Statistics() *Statistics {
+	loss := float64(p.PacketsSent-p.PacketsRecv) / float64(p.PacketsSent) * 100
+	var min, max, total time.Duration
+	if len(p.rtts) > 0 {
+		min = p.rtts[0]
+		max = p.rtts[0]
+	}
+	for _, rtt := range p.rtts {
+		if rtt < min {
+			min = rtt
+		}
+		if rtt > max {
+			max = rtt
+		}
+		total += rtt
+	}
+	s := Statistics{
+		PacketsSent: p.PacketsSent,
+		PacketsRecv: p.PacketsRecv,
+		PacketLoss:  loss,
+		Rtts:        p.rtts,
+		Addr:        p.addr,
+		IPAddr:      p.ipaddr,
+		MaxRtt:      max,
+		MinRtt:      min,
+	}
+	if len(p.rtts) > 0 {
+		s.AvgRtt = total / time.Duration(len(p.rtts))
+		var sumsquares time.Duration
+		for _, rtt := range p.rtts {
+			sumsquares += (rtt - s.AvgRtt) * (rtt - s.AvgRtt)
+		}
+		s.StdDevRtt = time.Duration(math.Sqrt(
+			float64(sumsquares / time.Duration(len(p.rtts)))))
+	}
+	return &s
+}
+
+func (p *Pinger) recvICMP(
+	conn *icmp.PacketConn,
+	recv chan<- *packet,
+	wg *sync.WaitGroup,
+) {
+	defer wg.Done()
+	for {
+		select {
+		case <-p.done:
+			return
+		default:
+			bytes := make([]byte, 512)
+			conn.SetReadDeadline(time.Now().Add(time.Millisecond * 100))
+			n, _, err := conn.ReadFrom(bytes)
+			if err != nil {
+				if neterr, ok := err.(*net.OpError); ok {
+					if neterr.Timeout() {
+						// Read timeout
+						continue
+					} else {
+						close(p.done)
+						return
+					}
+				}
+			}
+
+			recv <- &packet{bytes: bytes, nbytes: n}
+		}
+	}
+}
+
+func (p *Pinger) processPacket(recv *packet) error {
+	var bytes []byte
+	var proto int
+	if p.ipv4 {
+		if p.network == "ip" {
+			bytes = ipv4Payload(recv.bytes)
+		} else {
+			bytes = recv.bytes
+		}
+		proto = protocolICMP
+	} else {
+		bytes = recv.bytes
+		proto = protocolIPv6ICMP
+	}
+
+	var m *icmp.Message
+	var err error
+	if m, err = icmp.ParseMessage(proto, bytes[:recv.nbytes]); err != nil {
+		return fmt.Errorf("Error parsing icmp message")
+	}
+
+	if m.Type != ipv4.ICMPTypeEchoReply && m.Type != ipv6.ICMPTypeEchoReply {
+		// Not an echo reply, ignore it
+		return nil
+	}
+
+	outPkt := &Packet{
+		Nbytes: recv.nbytes,
+		IPAddr: p.ipaddr,
+	}
+
+	switch pkt := m.Body.(type) {
+	case *icmp.Echo:
+		outPkt.Rtt = time.Since(bytesToTime(pkt.Data[:timeSliceLength]))
+		outPkt.Seq = pkt.Seq
+		p.PacketsRecv += 1
+	default:
+		// Very bad, not sure how this can happen
+		return fmt.Errorf("Error, invalid ICMP echo reply. Body type: %T, %s",
+			pkt, pkt)
+	}
+
+	p.rtts = append(p.rtts, outPkt.Rtt)
+	handler := p.OnRecv
+	if handler != nil {
+		handler(outPkt)
+	}
+
+	return nil
+}
+
+func (p *Pinger) sendICMP(conn *icmp.PacketConn) error {
+	var typ icmp.Type
+	if p.ipv4 {
+		typ = ipv4.ICMPTypeEcho
+	} else {
+		typ = ipv6.ICMPTypeEchoRequest
+	}
+
+	var dst net.Addr = p.ipaddr
+	if p.network == "udp" {
+		dst = &net.UDPAddr{IP: p.ipaddr.IP, Zone: p.ipaddr.Zone}
+	}
+
+	t := timeToBytes(time.Now())
+	if p.size-timeSliceLength != 0 {
+		t = append(t, byteSliceOfSize(p.size-timeSliceLength)...)
+	}
+	bytes, err := (&icmp.Message{
+		Type: typ, Code: 0,
+		Body: &icmp.Echo{
+			ID:   rand.Intn(65535),
+			Seq:  p.sequence,
+			Data: t,
+		},
+	}).Marshal(nil)
+	if err != nil {
+		return err
+	}
+
+	for {
+		if _, err := conn.WriteTo(bytes, dst); err != nil {
+			if neterr, ok := err.(*net.OpError); ok {
+				if neterr.Err == syscall.ENOBUFS {
+					continue
+				}
+			}
+		}
+		p.PacketsSent += 1
+		p.sequence += 1
+		break
+	}
+	return nil
+}
+
+func (p *Pinger) listen(netProto string, source string) *icmp.PacketConn {
+	conn, err := icmp.ListenPacket(netProto, source)
+	if err != nil {
+		fmt.Printf("Error listening for ICMP packets: %s\n", err.Error())
+		close(p.done)
+		return nil
+	}
+	return conn
+}
+
+func byteSliceOfSize(n int) []byte {
+	b := make([]byte, n)
+	for i := 0; i < len(b); i++ {
+		b[i] = 1
+	}
+
+	return b
+}
+
+func ipv4Payload(b []byte) []byte {
+	if len(b) < ipv4.HeaderLen {
+		return b
+	}
+	hdrlen := int(b[0]&0x0f) << 2
+	return b[hdrlen:]
+}
+
+func bytesToTime(b []byte) time.Time {
+	var nsec int64
+	for i := uint8(0); i < 8; i++ {
+		nsec += int64(b[i]) << ((7 - i) * 8)
+	}
+	return time.Unix(nsec/1000000000, nsec%1000000000)
+}
+
+func isIPv4(ip net.IP) bool {
+	return len(ip.To4()) == net.IPv4len
+}
+
+func isIPv6(ip net.IP) bool {
+	return len(ip) == net.IPv6len
+}
+
+func timeToBytes(t time.Time) []byte {
+	nsec := t.UnixNano()
+	b := make([]byte, 8)
+	for i := uint8(0); i < 8; i++ {
+		b[i] = byte((nsec >> ((7 - i) * 8)) & 0xff)
+	}
+	return b
+}

vendor/github.com/sparrc/go-ping/ping_test.go

@@ -0,0 +1,266 @@
+package ping
+
+import (
+	"net"
+	"runtime/debug"
+	"testing"
+	"time"
+)
+
+func TestNewPingerValid(t *testing.T) {
+	p, err := NewPinger("www.google.com")
+	AssertNoError(t, err)
+	AssertEqualStrings(t, "www.google.com", p.Addr())
+	// DNS names should resolve into IP addresses
+	AssertNotEqualStrings(t, "www.google.com", p.IPAddr().String())
+	AssertTrue(t, isIPv4(p.IPAddr().IP))
+	AssertFalse(t, p.Privileged())
+	// Test that SetPrivileged works
+	p.SetPrivileged(true)
+	AssertTrue(t, p.Privileged())
+	// Test setting to ipv4 address
+	err = p.SetAddr("www.google.com")
+	AssertNoError(t, err)
+	AssertTrue(t, isIPv4(p.IPAddr().IP))
+	// Test setting to ipv6 address
+	err = p.SetAddr("ipv6.google.com")
+	AssertNoError(t, err)
+	AssertTrue(t, isIPv6(p.IPAddr().IP))
+
+	p, err = NewPinger("localhost")
+	AssertNoError(t, err)
+	AssertEqualStrings(t, "localhost", p.Addr())
+	// DNS names should resolve into IP addresses
+	AssertNotEqualStrings(t, "localhost", p.IPAddr().String())
+	AssertTrue(t, isIPv4(p.IPAddr().IP))
+	AssertFalse(t, p.Privileged())
+	// Test that SetPrivileged works
+	p.SetPrivileged(true)
+	AssertTrue(t, p.Privileged())
+	// Test setting to ipv4 address
+	err = p.SetAddr("www.google.com")
+	AssertNoError(t, err)
+	AssertTrue(t, isIPv4(p.IPAddr().IP))
+	// Test setting to ipv6 address
+	err = p.SetAddr("ipv6.google.com")
+	AssertNoError(t, err)
+	AssertTrue(t, isIPv6(p.IPAddr().IP))
+
+	p, err = NewPinger("127.0.0.1")
+	AssertNoError(t, err)
+	AssertEqualStrings(t, "127.0.0.1", p.Addr())
+	AssertTrue(t, isIPv4(p.IPAddr().IP))
+	AssertFalse(t, p.Privileged())
+	// Test that SetPrivileged works
+	p.SetPrivileged(true)
+	AssertTrue(t, p.Privileged())
+	// Test setting to ipv4 address
+	err = p.SetAddr("www.google.com")
+	AssertNoError(t, err)
+	AssertTrue(t, isIPv4(p.IPAddr().IP))
+	// Test setting to ipv6 address
+	err = p.SetAddr("ipv6.google.com")
+	AssertNoError(t, err)
+	AssertTrue(t, isIPv6(p.IPAddr().IP))
+
+	p, err = NewPinger("ipv6.google.com")
+	AssertNoError(t, err)
+	AssertEqualStrings(t, "ipv6.google.com", p.Addr())
+	// DNS names should resolve into IP addresses
+	AssertNotEqualStrings(t, "ipv6.google.com", p.IPAddr().String())
+	AssertTrue(t, isIPv6(p.IPAddr().IP))
+	AssertFalse(t, p.Privileged())
+	// Test that SetPrivileged works
+	p.SetPrivileged(true)
+	AssertTrue(t, p.Privileged())
+	// Test setting to ipv4 address
+	err = p.SetAddr("www.google.com")
+	AssertNoError(t, err)
+	AssertTrue(t, isIPv4(p.IPAddr().IP))
+	// Test setting to ipv6 address
+	err = p.SetAddr("ipv6.google.com")
+	AssertNoError(t, err)
+	AssertTrue(t, isIPv6(p.IPAddr().IP))
+
+	// ipv6 localhost:
+	p, err = NewPinger("::1")
+	AssertNoError(t, err)
+	AssertEqualStrings(t, "::1", p.Addr())
+	AssertTrue(t, isIPv6(p.IPAddr().IP))
+	AssertFalse(t, p.Privileged())
+	// Test that SetPrivileged works
+	p.SetPrivileged(true)
+	AssertTrue(t, p.Privileged())
+	// Test setting to ipv4 address
+	err = p.SetAddr("www.google.com")
+	AssertNoError(t, err)
+	AssertTrue(t, isIPv4(p.IPAddr().IP))
+	// Test setting to ipv6 address
+	err = p.SetAddr("ipv6.google.com")
+	AssertNoError(t, err)
+	AssertTrue(t, isIPv6(p.IPAddr().IP))
+}
+
+func TestNewPingerInvalid(t *testing.T) {
+	_, err := NewPinger("127.0.0.0.1")
+	AssertError(t, err, "127.0.0.0.1")
+
+	_, err = NewPinger("127..0.0.1")
+	AssertError(t, err, "127..0.0.1")
+
+	_, err = NewPinger("wtf")
+	AssertError(t, err, "wtf")
+
+	_, err = NewPinger(":::1")
+	AssertError(t, err, ":::1")
+
+	_, err = NewPinger("ipv5.google.com")
+	AssertError(t, err, "ipv5.google.com")
+}
+
+func TestSetIPAddr(t *testing.T) {
+	googleaddr, err := net.ResolveIPAddr("ip", "www.google.com")
+	if err != nil {
+		t.Fatal("Can't resolve www.google.com, can't run tests")
+	}
+
+	// Create a localhost ipv4 pinger
+	p, err := NewPinger("localhost")
+	AssertNoError(t, err)
+	AssertEqualStrings(t, "localhost", p.Addr())
+
+	// set IPAddr to google
+	p.SetIPAddr(googleaddr)
+	AssertEqualStrings(t, googleaddr.String(), p.Addr())
+}
+
+func TestStatisticsSunny(t *testing.T) {
+	// Create a localhost ipv4 pinger
+	p, err := NewPinger("localhost")
+	AssertNoError(t, err)
+	AssertEqualStrings(t, "localhost", p.Addr())
+
+	p.PacketsSent = 10
+	p.PacketsRecv = 10
+	p.rtts = []time.Duration{
+		time.Duration(1000),
+		time.Duration(1000),
+		time.Duration(1000),
+		time.Duration(1000),
+		time.Duration(1000),
+		time.Duration(1000),
+		time.Duration(1000),
+		time.Duration(1000),
+		time.Duration(1000),
+		time.Duration(1000),
+	}
+
+	stats := p.Statistics()
+	if stats.PacketsRecv != 10 {
+		t.Errorf("Expected %v, got %v", 10, stats.PacketsRecv)
+	}
+	if stats.PacketsSent != 10 {
+		t.Errorf("Expected %v, got %v", 10, stats.PacketsSent)
+	}
+	if stats.PacketLoss != 0 {
+		t.Errorf("Expected %v, got %v", 0, stats.PacketLoss)
+	}
+	if stats.MinRtt != time.Duration(1000) {
+		t.Errorf("Expected %v, got %v", time.Duration(1000), stats.MinRtt)
+	}
+	if stats.MaxRtt != time.Duration(1000) {
+		t.Errorf("Expected %v, got %v", time.Duration(1000), stats.MaxRtt)
+	}
+	if stats.AvgRtt != time.Duration(1000) {
+		t.Errorf("Expected %v, got %v", time.Duration(1000), stats.AvgRtt)
+	}
+	if stats.StdDevRtt != time.Duration(0) {
+		t.Errorf("Expected %v, got %v", time.Duration(0), stats.StdDevRtt)
+	}
+}
+
+func TestStatisticsLossy(t *testing.T) {
+	// Create a localhost ipv4 pinger
+	p, err := NewPinger("localhost")
+	AssertNoError(t, err)
+	AssertEqualStrings(t, "localhost", p.Addr())
+
+	p.PacketsSent = 20
+	p.PacketsRecv = 10
+	p.rtts = []time.Duration{
+		time.Duration(10),
+		time.Duration(1000),
+		time.Duration(1000),
+		time.Duration(10000),
+		time.Duration(1000),
+		time.Duration(800),
+		time.Duration(1000),
+		time.Duration(40),
+		time.Duration(100000),
+		time.Duration(1000),
+	}
+
+	stats := p.Statistics()
+	if stats.PacketsRecv != 10 {
+		t.Errorf("Expected %v, got %v", 10, stats.PacketsRecv)
+	}
+	if stats.PacketsSent != 20 {
+		t.Errorf("Expected %v, got %v", 20, stats.PacketsSent)
+	}
+	if stats.PacketLoss != 50 {
+		t.Errorf("Expected %v, got %v", 50, stats.PacketLoss)
+	}
+	if stats.MinRtt != time.Duration(10) {
+		t.Errorf("Expected %v, got %v", time.Duration(10), stats.MinRtt)
+	}
+	if stats.MaxRtt != time.Duration(100000) {
+		t.Errorf("Expected %v, got %v", time.Duration(100000), stats.MaxRtt)
+	}
+	if stats.AvgRtt != time.Duration(11585) {
+		t.Errorf("Expected %v, got %v", time.Duration(11585), stats.AvgRtt)
+	}
+	if stats.StdDevRtt != time.Duration(29603) {
+		t.Errorf("Expected %v, got %v", time.Duration(29603), stats.StdDevRtt)
+	}
+}
+
+// Test helpers
+func AssertNoError(t *testing.T, err error) {
+	if err != nil {
+		t.Errorf("Expected No Error but got %s, Stack:\n%s",
+			err, string(debug.Stack()))
+	}
+}
+
+func AssertError(t *testing.T, err error, info string) {
+	if err == nil {
+		t.Errorf("Expected Error but got %s, %s, Stack:\n%s",
+			err, info, string(debug.Stack()))
+	}
+}
+
+func AssertEqualStrings(t *testing.T, expected, actual string) {
+	if expected != actual {
+		t.Errorf("Expected %s, got %s, Stack:\n%s",
+			expected, actual, string(debug.Stack()))
+	}
+}
+
+func AssertNotEqualStrings(t *testing.T, expected, actual string) {
+	if expected == actual {
+		t.Errorf("Expected %s, got %s, Stack:\n%s",
+			expected, actual, string(debug.Stack()))
+	}
+}
+
+func AssertTrue(t *testing.T, b bool) {
+	if !b {
+		t.Errorf("Expected True, got False, Stack:\n%s", string(debug.Stack()))
+	}
+}
+
+func AssertFalse(t *testing.T, b bool) {
+	if b {
+		t.Errorf("Expected False, got True, Stack:\n%s", string(debug.Stack()))
+	}
+}

vendor/github.com/ulikunitz/xz/.gitignore

@@ -0,0 +1,25 @@
+# .gitignore
+
+TODO.html
+README.html
+
+lzma/writer.txt
+lzma/reader.txt
+
+cmd/gxz/gxz
+cmd/xb/xb
+
+# test executables
+*.test
+
+# profile files
+*.out
+
+# vim swap file
+.*.swp
+
+# executables on windows
+*.exe
+
+# default compression test file
+enwik8*

vendor/github.com/ulikunitz/xz/LICENSE

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

vendor/github.com/ulikunitz/xz/README.md

@@ -0,0 +1,71 @@
+# Package xz
+
+This Go language package supports the reading and writing of xz
+compressed streams. It includes also a gxz command for compressing and
+decompressing data. The package is completely written in Go and doesn't
+have any dependency on any C code.
+
+The package is currently under development. There might be bugs and APIs
+are not considered stable. At this time the package cannot compete with
+the xz tool regarding compression speed and size. The algorithms there
+have been developed over a long time and are highly optimized. However
+there are a number of improvements planned and I'm very optimistic about
+parallel compression and decompression. Stay tuned!
+
+# Using the API
+
+The following example program shows how to use the API.
+
+    package main
+
+    import (
+        "bytes"
+        "io"
+        "log"
+        "os"
+
+        "github.com/ulikunitz/xz"
+    )
+
+    func main() {
+        const text = "The quick brown fox jumps over the lazy dog.\n"
+        var buf bytes.Buffer
+        // compress text
+        w, err := xz.NewWriter(&buf)
+        if err != nil {
+            log.Fatalf("xz.NewWriter error %s", err)
+        }
+        if _, err := io.WriteString(w, text); err != nil {
+            log.Fatalf("WriteString error %s", err)
+        }
+        if err := w.Close(); err != nil {
+            log.Fatalf("w.Close error %s", err)
+        }
+        // decompress buffer and write output to stdout
+        r, err := xz.NewReader(&buf)
+        if err != nil {
+            log.Fatalf("NewReader error %s", err)
+        }
+        if _, err = io.Copy(os.Stdout, r); err != nil {
+            log.Fatalf("io.Copy error %s", err)
+        }
+    }
+
+# Using the gxz compression tool
+
+The package includes a gxz command line utility for compression and
+decompression.
+
+Use following command for installation:
+
+    $ go get github.com/ulikunitz/xz/cmd/gxz
+
+To test it call the following command.
+
+    $ gxz bigfile
+
+After some time a much smaller file bigfile.xz will replace bigfile.
+To decompress it use the following command.
+
+    $ gxz -d bigfile.xz
+

vendor/github.com/ulikunitz/xz/TODO.md

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

vendor/github.com/ulikunitz/xz/bits.go

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

vendor/github.com/ulikunitz/xz/bits_test.go

@@ -0,0 +1,33 @@
+// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package xz
+
+import (
+	"bytes"
+	"testing"
+)
+
+func TestUvarint(t *testing.T) {
+	tests := []uint64{0, 0x80, 0x100, 0xffffffff, 0x100000000, 1<<64 - 1}
+	p := make([]byte, 10)
+	for _, u := range tests {
+		p = p[:10]
+		n := putUvarint(p, u)
+		if n < 1 {
+			t.Fatalf("putUvarint returned %d", n)
+		}
+		r := bytes.NewReader(p[:n])
+		x, m, err := readUvarint(r)
+		if err != nil {
+			t.Fatalf("readUvarint returned %s", err)
+		}
+		if m != n {
+			t.Fatalf("readUvarint read %d bytes; want %d", m, n)
+		}
+		if x != u {
+			t.Fatalf("readUvarint returned 0x%x; want 0x%x", x, u)
+		}
+	}
+}

vendor/github.com/ulikunitz/xz/crc.go

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

vendor/github.com/ulikunitz/xz/example.go

@@ -0,0 +1,40 @@
+// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build ignore
+
+package main
+
+import (
+	"bytes"
+	"io"
+	"log"
+	"os"
+
+	"github.com/ulikunitz/xz"
+)
+
+func main() {
+	const text = "The quick brown fox jumps over the lazy dog.\n"
+	var buf bytes.Buffer
+	// compress text
+	w, err := xz.NewWriter(&buf)
+	if err != nil {
+		log.Fatalf("xz.NewWriter error %s", err)
+	}
+	if _, err := io.WriteString(w, text); err != nil {
+		log.Fatalf("WriteString error %s", err)
+	}
+	if err := w.Close(); err != nil {
+		log.Fatalf("w.Close error %s", err)
+	}
+	// decompress buffer and write output to stdout
+	r, err := xz.NewReader(&buf)
+	if err != nil {
+		log.Fatalf("NewReader error %s", err)
+	}
+	if _, err = io.Copy(os.Stdout, r); err != nil {
+		log.Fatalf("io.Copy error %s", err)
+	}
+}

vendor/github.com/ulikunitz/xz/format.go

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

vendor/github.com/ulikunitz/xz/format_test.go

@@ -0,0 +1,142 @@
+// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package xz
+
+import (
+	"bytes"
+	"testing"
+)
+
+func TestHeader(t *testing.T) {
+	h := header{flags: CRC32}
+	data, err := h.MarshalBinary()
+	if err != nil {
+		t.Fatalf("MarshalBinary error %s", err)
+	}
+	var g header
+	if err = g.UnmarshalBinary(data); err != nil {
+		t.Fatalf("UnmarshalBinary error %s", err)
+	}
+	if g != h {
+		t.Fatalf("unmarshalled %#v; want %#v", g, h)
+	}
+}
+
+func TestFooter(t *testing.T) {
+	f := footer{indexSize: 64, flags: CRC32}
+	data, err := f.MarshalBinary()
+	if err != nil {
+		t.Fatalf("MarshalBinary error %s", err)
+	}
+	var g footer
+	if err = g.UnmarshalBinary(data); err != nil {
+		t.Fatalf("UnmarshalBinary error %s", err)
+	}
+	if g != f {
+		t.Fatalf("unmarshalled %#v; want %#v", g, f)
+	}
+}
+
+func TestRecord(t *testing.T) {
+	r := record{1234567, 10000}
+	p, err := r.MarshalBinary()
+	if err != nil {
+		t.Fatalf("MarshalBinary error %s", err)
+	}
+	n := len(p)
+	buf := bytes.NewReader(p)
+	g, m, err := readRecord(buf)
+	if err != nil {
+		t.Fatalf("readFrom error %s", err)
+	}
+	if m != n {
+		t.Fatalf("read %d bytes; wrote %d", m, n)
+	}
+	if g.unpaddedSize != r.unpaddedSize {
+		t.Fatalf("got unpaddedSize %d; want %d", g.unpaddedSize,
+			r.unpaddedSize)
+	}
+	if g.uncompressedSize != r.uncompressedSize {
+		t.Fatalf("got uncompressedSize %d; want %d", g.uncompressedSize,
+			r.uncompressedSize)
+	}
+}
+
+func TestIndex(t *testing.T) {
+	records := []record{{1234, 1}, {2345, 2}}
+
+	var buf bytes.Buffer
+	n, err := writeIndex(&buf, records)
+	if err != nil {
+		t.Fatalf("writeIndex error %s", err)
+	}
+	if n != int64(buf.Len()) {
+		t.Fatalf("writeIndex returned %d; want %d", n, buf.Len())
+	}
+
+	// indicator
+	c, err := buf.ReadByte()
+	if err != nil {
+		t.Fatalf("buf.ReadByte error %s", err)
+	}
+	if c != 0 {
+		t.Fatalf("indicator %d; want %d", c, 0)
+	}
+
+	g, m, err := readIndexBody(&buf)
+	if err != nil {
+		for i, r := range g {
+			t.Logf("records[%d] %v", i, r)
+		}
+		t.Fatalf("readIndexBody error %s", err)
+	}
+	if m != n-1 {
+		t.Fatalf("readIndexBody returned %d; want %d", m, n-1)
+	}
+	for i, rec := range records {
+		if g[i] != rec {
+			t.Errorf("records[%d] is %v; want %v", i, g[i], rec)
+		}
+	}
+}
+
+func TestBlockHeader(t *testing.T) {
+	h := blockHeader{
+		compressedSize:   1234,
+		uncompressedSize: -1,
+		filters:          []filter{&lzmaFilter{4096}},
+	}
+	data, err := h.MarshalBinary()
+	if err != nil {
+		t.Fatalf("MarshalBinary error %s", err)
+	}
+
+	r := bytes.NewReader(data)
+	g, n, err := readBlockHeader(r)
+	if err != nil {
+		t.Fatalf("readBlockHeader error %s", err)
+	}
+	if n != len(data) {
+		t.Fatalf("readBlockHeader returns %d bytes; want %d", n,
+			len(data))
+	}
+	if g.compressedSize != h.compressedSize {
+		t.Errorf("got compressedSize %d; want %d",
+			g.compressedSize, h.compressedSize)
+	}
+	if g.uncompressedSize != h.uncompressedSize {
+		t.Errorf("got uncompressedSize %d; want %d",
+			g.uncompressedSize, h.uncompressedSize)
+	}
+	if len(g.filters) != len(h.filters) {
+		t.Errorf("got len(filters) %d; want %d",
+			len(g.filters), len(h.filters))
+	}
+	glf := g.filters[0].(*lzmaFilter)
+	hlf := h.filters[0].(*lzmaFilter)
+	if glf.dictCap != hlf.dictCap {
+		t.Errorf("got dictCap %d; want %d", glf.dictCap, hlf.dictCap)
+	}
+}

vendor/github.com/ulikunitz/xz/internal/hash/cyclic_poly.go

@@ -0,0 +1,181 @@
+// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package hash
+
+// CyclicPoly provides a cyclic polynomial rolling hash.
+type CyclicPoly struct {
+	h uint64
+	p []uint64
+	i int
+}
+
+// ror rotates the unsigned 64-bit integer to right. The argument s must be
+// less than 64.
+func ror(x uint64, s uint) uint64 {
+	return (x >> s) | (x << (64 - s))
+}
+
+// NewCyclicPoly creates a new instance of the CyclicPoly structure. The
+// argument n gives the number of bytes for which a hash will be executed.
+// This number must be positive; the method panics if this isn't the case.
+func NewCyclicPoly(n int) *CyclicPoly {
+	if n < 1 {
+		panic("argument n must be positive")
+	}
+	return &CyclicPoly{p: make([]uint64, 0, n)}
+}
+
+// Len returns the length of the byte sequence for which a hash is generated.
+func (r *CyclicPoly) Len() int {
+	return cap(r.p)
+}
+
+// RollByte hashes the next byte and returns a hash value. The complete becomes
+// available after at least Len() bytes have been hashed.
+func (r *CyclicPoly) RollByte(x byte) uint64 {
+	y := hash[x]
+	if len(r.p) < cap(r.p) {
+		r.h = ror(r.h, 1) ^ y
+		r.p = append(r.p, y)
+	} else {
+		r.h ^= ror(r.p[r.i], uint(cap(r.p)-1))
+		r.h = ror(r.h, 1) ^ y
+		r.p[r.i] = y
+		r.i = (r.i + 1) % cap(r.p)
+	}
+	return r.h
+}
+
+// Stores the hash for the individual bytes.
+var hash = [256]uint64{
+	0x2e4fc3f904065142, 0xc790984cfbc99527,
+	0x879f95eb8c62f187, 0x3b61be86b5021ef2,
+	0x65a896a04196f0a5, 0xc5b307b80470b59e,
+	0xd3bff376a70df14b, 0xc332f04f0b3f1701,
+	0x753b5f0e9abf3e0d, 0xb41538fdfe66ef53,
+	0x1906a10c2c1c0208, 0xfb0c712a03421c0d,
+	0x38be311a65c9552b, 0xfee7ee4ca6445c7e,
+	0x71aadeded184f21e, 0xd73426fccda23b2d,
+	0x29773fb5fb9600b5, 0xce410261cd32981a,
+	0xfe2848b3c62dbc2d, 0x459eaaff6e43e11c,
+	0xc13e35fc9c73a887, 0xf30ed5c201e76dbc,
+	0xa5f10b3910482cea, 0x2945d59be02dfaad,
+	0x06ee334ff70571b5, 0xbabf9d8070f44380,
+	0xee3e2e9912ffd27c, 0x2a7118d1ea6b8ea7,
+	0x26183cb9f7b1664c, 0xea71dac7da068f21,
+	0xea92eca5bd1d0bb7, 0x415595862defcd75,
+	0x248a386023c60648, 0x9cf021ab284b3c8a,
+	0xfc9372df02870f6c, 0x2b92d693eeb3b3fc,
+	0x73e799d139dc6975, 0x7b15ae312486363c,
+	0xb70e5454a2239c80, 0x208e3fb31d3b2263,
+	0x01f563cabb930f44, 0x2ac4533d2a3240d8,
+	0x84231ed1064f6f7c, 0xa9f020977c2a6d19,
+	0x213c227271c20122, 0x09fe8a9a0a03d07a,
+	0x4236dc75bcaf910c, 0x460a8b2bead8f17e,
+	0xd9b27be1aa07055f, 0xd202d5dc4b11c33e,
+	0x70adb010543bea12, 0xcdae938f7ea6f579,
+	0x3f3d870208672f4d, 0x8e6ccbce9d349536,
+	0xe4c0871a389095ae, 0xf5f2a49152bca080,
+	0x9a43f9b97269934e, 0xc17b3753cb6f475c,
+	0xd56d941e8e206bd4, 0xac0a4f3e525eda00,
+	0xa06d5a011912a550, 0x5537ed19537ad1df,
+	0xa32fe713d611449d, 0x2a1d05b47c3b579f,
+	0x991d02dbd30a2a52, 0x39e91e7e28f93eb0,
+	0x40d06adb3e92c9ac, 0x9b9d3afde1c77c97,
+	0x9a3f3f41c02c616f, 0x22ecd4ba00f60c44,
+	0x0b63d5d801708420, 0x8f227ca8f37ffaec,
+	0x0256278670887c24, 0x107e14877dbf540b,
+	0x32c19f2786ac1c05, 0x1df5b12bb4bc9c61,
+	0xc0cac129d0d4c4e2, 0x9fdb52ee9800b001,
+	0x31f601d5d31c48c4, 0x72ff3c0928bcaec7,
+	0xd99264421147eb03, 0x535a2d6d38aefcfe,
+	0x6ba8b4454a916237, 0xfa39366eaae4719c,
+	0x10f00fd7bbb24b6f, 0x5bd23185c76c84d4,
+	0xb22c3d7e1b00d33f, 0x3efc20aa6bc830a8,
+	0xd61c2503fe639144, 0x30ce625441eb92d3,
+	0xe5d34cf359e93100, 0xa8e5aa13f2b9f7a5,
+	0x5c2b8d851ca254a6, 0x68fb6c5e8b0d5fdf,
+	0xc7ea4872c96b83ae, 0x6dd5d376f4392382,
+	0x1be88681aaa9792f, 0xfef465ee1b6c10d9,
+	0x1f98b65ed43fcb2e, 0x4d1ca11eb6e9a9c9,
+	0x7808e902b3857d0b, 0x171c9c4ea4607972,
+	0x58d66274850146df, 0x42b311c10d3981d1,
+	0x647fa8c621c41a4c, 0xf472771c66ddfedc,
+	0x338d27e3f847b46b, 0x6402ce3da97545ce,
+	0x5162db616fc38638, 0x9c83be97bc22a50e,
+	0x2d3d7478a78d5e72, 0xe621a9b938fd5397,
+	0x9454614eb0f81c45, 0x395fb6e742ed39b6,
+	0x77dd9179d06037bf, 0xc478d0fee4d2656d,
+	0x35d9d6cb772007af, 0x83a56e92c883f0f6,
+	0x27937453250c00a1, 0x27bd6ebc3a46a97d,
+	0x9f543bf784342d51, 0xd158f38c48b0ed52,
+	0x8dd8537c045f66b4, 0x846a57230226f6d5,
+	0x6b13939e0c4e7cdf, 0xfca25425d8176758,
+	0x92e5fc6cd52788e6, 0x9992e13d7a739170,
+	0x518246f7a199e8ea, 0xf104c2a71b9979c7,
+	0x86b3ffaabea4768f, 0x6388061cf3e351ad,
+	0x09d9b5295de5bbb5, 0x38bf1638c2599e92,
+	0x1d759846499e148d, 0x4c0ff015e5f96ef4,
+	0xa41a94cfa270f565, 0x42d76f9cb2326c0b,
+	0x0cf385dd3c9c23ba, 0x0508a6c7508d6e7a,
+	0x337523aabbe6cf8d, 0x646bb14001d42b12,
+	0xc178729d138adc74, 0xf900ef4491f24086,
+	0xee1a90d334bb5ac4, 0x9755c92247301a50,
+	0xb999bf7c4ff1b610, 0x6aeeb2f3b21e8fc9,
+	0x0fa8084cf91ac6ff, 0x10d226cf136e6189,
+	0xd302057a07d4fb21, 0x5f03800e20a0fcc3,
+	0x80118d4ae46bd210, 0x58ab61a522843733,
+	0x51edd575c5432a4b, 0x94ee6ff67f9197f7,
+	0x765669e0e5e8157b, 0xa5347830737132f0,
+	0x3ba485a69f01510c, 0x0b247d7b957a01c3,
+	0x1b3d63449fd807dc, 0x0fdc4721c30ad743,
+	0x8b535ed3829b2b14, 0xee41d0cad65d232c,
+	0xe6a99ed97a6a982f, 0x65ac6194c202003d,
+	0x692accf3a70573eb, 0xcc3c02c3e200d5af,
+	0x0d419e8b325914a3, 0x320f160f42c25e40,
+	0x00710d647a51fe7a, 0x3c947692330aed60,
+	0x9288aa280d355a7a, 0xa1806a9b791d1696,
+	0x5d60e38496763da1, 0x6c69e22e613fd0f4,
+	0x977fc2a5aadffb17, 0xfb7bd063fc5a94ba,
+	0x460c17992cbaece1, 0xf7822c5444d3297f,
+	0x344a9790c69b74aa, 0xb80a42e6cae09dce,
+	0x1b1361eaf2b1e757, 0xd84c1e758e236f01,
+	0x88e0b7be347627cc, 0x45246009b7a99490,
+	0x8011c6dd3fe50472, 0xc341d682bffb99d7,
+	0x2511be93808e2d15, 0xd5bc13d7fd739840,
+	0x2a3cd030679ae1ec, 0x8ad9898a4b9ee157,
+	0x3245fef0a8eaf521, 0x3d6d8dbbb427d2b0,
+	0x1ed146d8968b3981, 0x0c6a28bf7d45f3fc,
+	0x4a1fd3dbcee3c561, 0x4210ff6a476bf67e,
+	0xa559cce0d9199aac, 0xde39d47ef3723380,
+	0xe5b69d848ce42e35, 0xefa24296f8e79f52,
+	0x70190b59db9a5afc, 0x26f166cdb211e7bf,
+	0x4deaf2df3c6b8ef5, 0xf171dbdd670f1017,
+	0xb9059b05e9420d90, 0x2f0da855c9388754,
+	0x611d5e9ab77949cc, 0x2912038ac01163f4,
+	0x0231df50402b2fba, 0x45660fc4f3245f58,
+	0xb91cc97c7c8dac50, 0xb72d2aafe4953427,
+	0xfa6463f87e813d6b, 0x4515f7ee95d5c6a2,
+	0x1310e1c1a48d21c3, 0xad48a7810cdd8544,
+	0x4d5bdfefd5c9e631, 0xa43ed43f1fdcb7de,
+	0xe70cfc8fe1ee9626, 0xef4711b0d8dda442,
+	0xb80dd9bd4dab6c93, 0xa23be08d31ba4d93,
+	0x9b37db9d0335a39c, 0x494b6f870f5cfebc,
+	0x6d1b3c1149dda943, 0x372c943a518c1093,
+	0xad27af45e77c09c4, 0x3b6f92b646044604,
+	0xac2917909f5fcf4f, 0x2069a60e977e5557,
+	0x353a469e71014de5, 0x24be356281f55c15,
+	0x2b6d710ba8e9adea, 0x404ad1751c749c29,
+	0xed7311bf23d7f185, 0xba4f6976b4acc43e,
+	0x32d7198d2bc39000, 0xee667019014d6e01,
+	0x494ef3e128d14c83, 0x1f95a152baecd6be,
+	0x201648dff1f483a5, 0x68c28550c8384af6,
+	0x5fc834a6824a7f48, 0x7cd06cb7365eaf28,
+	0xd82bbd95e9b30909, 0x234f0d1694c53f6d,
+	0xd2fb7f4a96d83f4a, 0xff0d5da83acac05e,
+	0xf8f6b97f5585080a, 0x74236084be57b95b,
+	0xa25e40c03bbc36ad, 0x6b6e5c14ce88465b,
+	0x4378ffe93e1528c5, 0x94ca92a17118e2d2,
+}

vendor/github.com/ulikunitz/xz/internal/hash/cyclic_poly_test.go

@@ -0,0 +1,30 @@
+// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package hash
+
+import "testing"
+
+func TestCyclicPolySimple(t *testing.T) {
+	p := []byte("abcde")
+	r := NewCyclicPoly(4)
+	h2 := Hashes(r, p)
+	for i, h := range h2 {
+		w := Hashes(r, p[i:i+4])[0]
+		t.Logf("%d h=%#016x w=%#016x", i, h, w)
+		if h != w {
+			t.Errorf("rolling hash %d: %#016x; want %#016x",
+				i, h, w)
+		}
+	}
+}
+
+func BenchmarkCyclicPoly(b *testing.B) {
+	p := makeBenchmarkBytes(4096)
+	r := NewCyclicPoly(4)
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		Hashes(r, p)
+	}
+}

vendor/github.com/ulikunitz/xz/internal/hash/doc.go

@@ -0,0 +1,14 @@
+// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+/*
+Package hash provides rolling hashes.
+
+Rolling hashes have to be used for maintaining the positions of n-byte
+sequences in the dictionary buffer.
+
+The package provides currently the Rabin-Karp rolling hash and a Cyclic
+Polynomial hash. Both support the Hashes method to be used with an interface.
+*/
+package hash

vendor/github.com/ulikunitz/xz/internal/hash/rabin_karp.go

@@ -0,0 +1,66 @@
+// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package hash
+
+// A is the default constant for Robin-Karp rolling hash. This is a random
+// prime.
+const A = 0x97b548add41d5da1
+
+// RabinKarp supports the computation of a rolling hash.
+type RabinKarp struct {
+	A uint64
+	// a^n
+	aOldest uint64
+	h       uint64
+	p       []byte
+	i       int
+}
+
+// NewRabinKarp creates a new RabinKarp value. The argument n defines the
+// length of the byte sequence to be hashed. The default constant will will be
+// used.
+func NewRabinKarp(n int) *RabinKarp {
+	return NewRabinKarpConst(n, A)
+}
+
+// NewRabinKarpConst creates a new RabinKarp value. The argument n defines the
+// length of the byte sequence to be hashed. The argument a provides the
+// constant used to compute the hash.
+func NewRabinKarpConst(n int, a uint64) *RabinKarp {
+	if n <= 0 {
+		panic("number of bytes n must be positive")
+	}
+	aOldest := uint64(1)
+	// There are faster methods. For the small n required by the LZMA
+	// compressor O(n) is sufficient.
+	for i := 0; i < n; i++ {
+		aOldest *= a
+	}
+	return &RabinKarp{
+		A: a, aOldest: aOldest,
+		p: make([]byte, 0, n),
+	}
+}
+
+// Len returns the length of the byte sequence.
+func (r *RabinKarp) Len() int {
+	return cap(r.p)
+}
+
+// RollByte computes the hash after x has been added.
+func (r *RabinKarp) RollByte(x byte) uint64 {
+	if len(r.p) < cap(r.p) {
+		r.h += uint64(x)
+		r.h *= r.A
+		r.p = append(r.p, x)
+	} else {
+		r.h -= uint64(r.p[r.i]) * r.aOldest
+		r.h += uint64(x)
+		r.h *= r.A
+		r.p[r.i] = x
+		r.i = (r.i + 1) % cap(r.p)
+	}
+	return r.h
+}

vendor/github.com/ulikunitz/xz/internal/hash/rabin_karp_test.go

@@ -0,0 +1,42 @@
+// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package hash
+
+import (
+	"math/rand"
+	"testing"
+)
+
+func TestRabinKarpSimple(t *testing.T) {
+	p := []byte("abcde")
+	r := NewRabinKarp(4)
+	h2 := Hashes(r, p)
+	for i, h := range h2 {
+		w := Hashes(r, p[i:i+4])[0]
+		t.Logf("%d h=%#016x w=%#016x", i, h, w)
+		if h != w {
+			t.Errorf("rolling hash %d: %#016x; want %#016x",
+				i, h, w)
+		}
+	}
+}
+
+func makeBenchmarkBytes(n int) []byte {
+	rnd := rand.New(rand.NewSource(42))
+	p := make([]byte, n)
+	for i := range p {
+		p[i] = byte(rnd.Uint32())
+	}
+	return p
+}
+
+func BenchmarkRabinKarp(b *testing.B) {
+	p := makeBenchmarkBytes(4096)
+	r := NewRabinKarp(4)
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		Hashes(r, p)
+	}
+}

vendor/github.com/ulikunitz/xz/internal/hash/roller.go

@@ -0,0 +1,29 @@
+// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package hash
+
+// Roller provides an interface for rolling hashes. The hash value will become
+// valid after hash has been called Len times.
+type Roller interface {
+	Len() int
+	RollByte(x byte) uint64
+}
+
+// Hashes computes all hash values for the array p. Note that the state of the
+// roller is changed.
+func Hashes(r Roller, p []byte) []uint64 {
+	n := r.Len()
+	if len(p) < n {
+		return nil
+	}
+	h := make([]uint64, len(p)-n+1)
+	for i := 0; i < n-1; i++ {
+		r.RollByte(p[i])
+	}
+	for i := range h {
+		h[i] = r.RollByte(p[i+n-1])
+	}
+	return h
+}

vendor/github.com/ulikunitz/xz/internal/randtxt/groupreader.go

@@ -0,0 +1,82 @@
+// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package randtxt
+
+import (
+	"bufio"
+	"io"
+	"unicode"
+)
+
+// GroupReader groups the incoming text in groups of 5, whereby the
+// number of groups per line can be controlled.
+type GroupReader struct {
+	R             io.ByteReader
+	GroupsPerLine int
+	off           int64
+	eof           bool
+}
+
+// NewGroupReader creates a new group reader.
+func NewGroupReader(r io.Reader) *GroupReader {
+	return &GroupReader{R: bufio.NewReader(r)}
+}
+
+// Read formats the data provided by the internal reader in groups of 5
+// characters. If GroupsPerLine hasn't been initialized 8 groups per
+// line will be produced.
+func (r *GroupReader) Read(p []byte) (n int, err error) {
+	if r.eof {
+		return 0, io.EOF
+	}
+	groupsPerLine := r.GroupsPerLine
+	if groupsPerLine < 1 {
+		groupsPerLine = 8
+	}
+	lineLen := int64(groupsPerLine * 6)
+	var c byte
+	for i := range p {
+		switch {
+		case r.off%lineLen == lineLen-1:
+			if i+1 == len(p) && len(p) > 1 {
+				return i, nil
+			}
+			c = '\n'
+		case r.off%6 == 5:
+			if i+1 == len(p) && len(p) > 1 {
+				return i, nil
+			}
+			c = ' '
+		default:
+			c, err = r.R.ReadByte()
+			if err == io.EOF {
+				r.eof = true
+				if i > 0 {
+					switch p[i-1] {
+					case ' ':
+						p[i-1] = '\n'
+						fallthrough
+					case '\n':
+						return i, io.EOF
+					}
+				}
+				p[i] = '\n'
+				return i + 1, io.EOF
+			}
+			if err != nil {
+				return i, err
+			}
+			switch {
+			case c == ' ':
+				c = '_'
+			case !unicode.IsPrint(rune(c)):
+				c = '-'
+			}
+		}
+		p[i] = c
+		r.off++
+	}
+	return len(p), nil
+}

vendor/github.com/ulikunitz/xz/internal/randtxt/probs.go

@@ -0,0 +1,185 @@
+// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package randtxt supports the generation of random text using a
+// trigram model for the English language.
+package randtxt
+
+import (
+	"math"
+	"math/rand"
+	"sort"
+)
+
+// ngram stores an entry from the language model.
+type ngram struct {
+	s   string
+	lgP float64
+	lgQ float64
+}
+
+// ngrams represents a slice of ngram values and is used to represent a
+// language model.
+type ngrams []ngram
+
+func (s ngrams) Len() int           { return len(s) }
+func (s ngrams) Swap(i, j int)      { s[i], s[j] = s[j], s[i] }
+func (s ngrams) Less(i, j int) bool { return s[i].s < s[j].s }
+
+// Sorts the language model in the sequence of their ngrams.
+func (s ngrams) Sort() { sort.Sort(s) }
+
+// Search is looking for an ngram or the position where it would be
+// inserted.
+func (s ngrams) Search(g string) int {
+	return sort.Search(len(s), func(k int) bool { return s[k].s >= g })
+}
+
+// prob represents a string, usually an ngram, and a probability value.
+type prob struct {
+	s string
+	p float64
+}
+
+// probs is a slice of prob values that can be sorted and searched.
+type probs []prob
+
+func (s probs) Len() int           { return len(s) }
+func (s probs) Swap(i, j int)      { s[i], s[j] = s[j], s[i] }
+func (s probs) Less(i, j int) bool { return s[i].s < s[j].s }
+
+// SortByNgram sorts the probs slice by ngram, field s.
+func (s probs) SortByNgram() { sort.Sort(s) }
+
+// SortsByProb sorts the probs slice by probability, field p.
+func (s probs) SortByProb() { sort.Sort(byProb{s}) }
+
+// SearchNgram searches for an ngram or the position where it would be
+// inserted.
+func (s probs) SearchNgram(g string) int {
+	return sort.Search(len(s), func(k int) bool { return s[k].s >= g })
+}
+
+// SearchProb searches ngrams for a specific probability or where it
+// would be inserted.
+func (s probs) SearchProb(p float64) int {
+	return sort.Search(len(s), func(k int) bool { return s[k].p >= p })
+}
+
+// byProb is used to sort probs slice by probability, field p.
+type byProb struct {
+	probs
+}
+
+func (s byProb) Less(i, j int) bool {
+	return s.probs[i].p < s.probs[j].p
+}
+
+// cdf can be used to setup a cumulative distribution function
+// represented by a probs slice. We should have returned an actual
+// function.
+func cdf(n int, p func(i int) prob) probs {
+	prs := make(probs, n)
+	sum := 0.0
+	for i := range prs {
+		pr := p(i)
+		sum += pr.p
+		prs[i] = pr
+	}
+	q := 1.0 / sum
+	x := 0.0
+	for i, pr := range prs {
+		x += pr.p * q
+		if x > 1.0 {
+			x = 1.0
+		}
+		prs[i].p = x
+	}
+	if !sort.IsSorted(byProb{prs}) {
+		panic("cdf not sorted")
+	}
+	return prs
+}
+
+// pCDFOfLM converts a language model into a cumulative distribution
+// function represented by probs.
+func pCDFOfLM(lm ngrams) probs {
+	return cdf(len(lm), func(i int) prob {
+		return prob{lm[i].s, math.Exp2(lm[i].lgP)}
+	})
+}
+
+// cCDF converts a ngrams slice into a cumulative distribution function
+// using the conditional probability lgQ.
+func cCDF(s ngrams) probs {
+	return cdf(len(s), func(i int) prob {
+		return prob{s[i].s, math.Exp2(s[i].lgQ)}
+	})
+}
+
+// comap contains a map of conditional distribution function for the
+// last character.
+type comap map[string]probs
+
+// comapOfLM converts a language model in a map of conditional
+// distribution functions.
+func comapOfLM(lm ngrams) comap {
+	if !sort.IsSorted(lm) {
+		panic("lm is not sorted")
+	}
+	m := make(comap, 26*26)
+	for i := 0; i < len(lm); {
+		j := i
+		g := lm[i].s
+		g2 := g[:2]
+		z := g2 + "Z"
+		i = lm.Search(z)
+		if i >= len(lm) || lm[i].s != z {
+			panic("unexpected search result")
+		}
+		i++
+		m[g2] = cCDF(lm[j:i])
+	}
+	return m
+}
+
+// trigram returns the trigram with prefix g2 using a probability value
+// in the range [0.0,1.0).
+func (c comap) trigram(g2 string, p float64) string {
+	prs := c[g2]
+	i := prs.SearchProb(p)
+	return prs[i].s
+}
+
+var (
+	// CDF for normal probabilities
+	pcdf = pCDFOfLM(englm3)
+	// map of two letter conditionals
+	cmap = comapOfLM(englm3)
+)
+
+// Reader generates a stream of text of uppercase letters with trigrams
+// distributed according to a language model of the English language.
+type Reader struct {
+	rnd *rand.Rand
+	g3  string
+}
+
+// NewReader creates a new reader. The argument src must create a uniformly
+// distributed stream of random values.
+func NewReader(src rand.Source) *Reader {
+	rnd := rand.New(src)
+	i := pcdf.SearchProb(rnd.Float64())
+	return &Reader{rnd, pcdf[i].s}
+}
+
+// Read reads random text. The Read function will always return len(p)
+// bytes and will never return an error.
+func (r *Reader) Read(p []byte) (n int, err error) {
+	for i := range p {
+		r.g3 = cmap.trigram(r.g3[1:], r.rnd.Float64())
+		p[i] = r.g3[2]
+	}
+	return len(p), nil
+}

vendor/github.com/ulikunitz/xz/internal/randtxt/probs_test.go

@@ -0,0 +1,37 @@
+// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package randtxt
+
+import (
+	"bufio"
+	"io"
+	"math/rand"
+	"testing"
+)
+
+func TestReader(t *testing.T) {
+	lr := io.LimitReader(NewReader(rand.NewSource(13)), 195)
+	pretty := NewGroupReader(lr)
+	scanner := bufio.NewScanner(pretty)
+	for scanner.Scan() {
+		t.Log(scanner.Text())
+	}
+	if err := scanner.Err(); err != nil {
+		t.Fatalf("scanner error %s", err)
+	}
+}
+
+func TestComap(t *testing.T) {
+	prs := cmap["TH"]
+	for _, p := range prs[3:6] {
+		t.Logf("%v", p)
+	}
+	p := 0.2
+	x := cmap.trigram("TH", p)
+	if x != "THE" {
+		t.Fatalf("cmap.trigram(%q, %.1f) returned %q; want %q",
+			"TH", p, x, "THE")
+	}
+}

vendor/github.com/ulikunitz/xz/internal/xlog/xlog.go

@@ -0,0 +1,457 @@
+// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package xlog provides a simple logging package that allows to disable
+// certain message categories. It defines a type, Logger, with multiple
+// methods for formatting output. The package has also a predefined
+// 'standard' Logger accessible through helper function Print[f|ln],
+// Fatal[f|ln], Panic[f|ln], Warn[f|ln], Print[f|ln] and Debug[f|ln]
+// that are easier to use then creating a Logger manually. That logger
+// writes to standard error and prints the date and time of each logged
+// message, which can be configured using the function SetFlags.
+//
+// The Fatal functions call os.Exit(1) after the message is output
+// unless not suppressed by the flags. The Panic functions call panic
+// after the writing the log message unless suppressed.
+package xlog
+
+import (
+	"fmt"
+	"io"
+	"os"
+	"runtime"
+	"sync"
+	"time"
+)
+
+// The flags define what information is prefixed to each log entry
+// generated by the Logger. The Lno* versions allow the suppression of
+// specific output. The bits are or'ed together to control what will be
+// printed. There is no control over the order of the items printed and
+// the format. The full format is:
+//
+//   2009-01-23 01:23:23.123123 /a/b/c/d.go:23: message
+//
+const (
+	Ldate         = 1 << iota // the date: 2009-01-23
+	Ltime                     // the time: 01:23:23
+	Lmicroseconds             // microsecond resolution: 01:23:23.123123
+	Llongfile                 // full file name and line number: /a/b/c/d.go:23
+	Lshortfile                // final file name element and line number: d.go:23
+	Lnopanic                  // suppresses output from Panic[f|ln] but not the panic call
+	Lnofatal                  // suppresses output from Fatal[f|ln] but not the exit
+	Lnowarn                   // suppresses output from Warn[f|ln]
+	Lnoprint                  // suppresses output from Print[f|ln]
+	Lnodebug                  // suppresses output from Debug[f|ln]
+	// initial values for the standard logger
+	Lstdflags = Ldate | Ltime | Lnodebug
+)
+
+// A Logger represents an active logging object that generates lines of
+// output to an io.Writer. Each logging operation if not suppressed
+// makes a single call to the Writer's Write method. A Logger can be
+// used simultaneously from multiple goroutines; it guarantees to
+// serialize access to the Writer.
+type Logger struct {
+	mu sync.Mutex // ensures atomic writes; and protects the following
+	// fields
+	prefix string    // prefix to write at beginning of each line
+	flag   int       // properties
+	out    io.Writer // destination for output
+	buf    []byte    // for accumulating text to write
+}
+
+// New creates a new Logger. The out argument sets the destination to
+// which the log output will be written. The prefix appears at the
+// beginning of each log line. The flag argument defines the logging
+// properties.
+func New(out io.Writer, prefix string, flag int) *Logger {
+	return &Logger{out: out, prefix: prefix, flag: flag}
+}
+
+// std is the standard logger used by the package scope functions.
+var std = New(os.Stderr, "", Lstdflags)
+
+// itoa converts the integer to ASCII. A negative widths will avoid
+// zero-padding. The function supports only non-negative integers.
+func itoa(buf *[]byte, i int, wid int) {
+	var u = uint(i)
+	if u == 0 && wid <= 1 {
+		*buf = append(*buf, '0')
+		return
+	}
+	var b [32]byte
+	bp := len(b)
+	for ; u > 0 || wid > 0; u /= 10 {
+		bp--
+		wid--
+		b[bp] = byte(u%10) + '0'
+	}
+	*buf = append(*buf, b[bp:]...)
+}
+
+// formatHeader puts the header into the buf field of the buffer.
+func (l *Logger) formatHeader(t time.Time, file string, line int) {
+	l.buf = append(l.buf, l.prefix...)
+	if l.flag&(Ldate|Ltime|Lmicroseconds) != 0 {
+		if l.flag&Ldate != 0 {
+			year, month, day := t.Date()
+			itoa(&l.buf, year, 4)
+			l.buf = append(l.buf, '-')
+			itoa(&l.buf, int(month), 2)
+			l.buf = append(l.buf, '-')
+			itoa(&l.buf, day, 2)
+			l.buf = append(l.buf, ' ')
+		}
+		if l.flag&(Ltime|Lmicroseconds) != 0 {
+			hour, min, sec := t.Clock()
+			itoa(&l.buf, hour, 2)
+			l.buf = append(l.buf, ':')
+			itoa(&l.buf, min, 2)
+			l.buf = append(l.buf, ':')
+			itoa(&l.buf, sec, 2)
+			if l.flag&Lmicroseconds != 0 {
+				l.buf = append(l.buf, '.')
+				itoa(&l.buf, t.Nanosecond()/1e3, 6)
+			}
+			l.buf = append(l.buf, ' ')
+		}
+	}
+	if l.flag&(Lshortfile|Llongfile) != 0 {
+		if l.flag&Lshortfile != 0 {
+			short := file
+			for i := len(file) - 1; i > 0; i-- {
+				if file[i] == '/' {
+					short = file[i+1:]
+					break
+				}
+			}
+			file = short
+		}
+		l.buf = append(l.buf, file...)
+		l.buf = append(l.buf, ':')
+		itoa(&l.buf, line, -1)
+		l.buf = append(l.buf, ": "...)
+	}
+}
+
+func (l *Logger) output(calldepth int, now time.Time, s string) error {
+	var file string
+	var line int
+	if l.flag&(Lshortfile|Llongfile) != 0 {
+		l.mu.Unlock()
+		var ok bool
+		_, file, line, ok = runtime.Caller(calldepth)
+		if !ok {
+			file = "???"
+			line = 0
+		}
+		l.mu.Lock()
+	}
+	l.buf = l.buf[:0]
+	l.formatHeader(now, file, line)
+	l.buf = append(l.buf, s...)
+	if len(s) == 0 || s[len(s)-1] != '\n' {
+		l.buf = append(l.buf, '\n')
+	}
+	_, err := l.out.Write(l.buf)
+	return err
+}
+
+// Output writes the string s with the header controlled by the flags to
+// the l.out writer. A newline will be appended if s doesn't end in a
+// newline. Calldepth is used to recover the PC, although all current
+// calls of Output use the call depth 2. Access to the function is serialized.
+func (l *Logger) Output(calldepth, noflag int, v ...interface{}) error {
+	now := time.Now()
+	l.mu.Lock()
+	defer l.mu.Unlock()
+	if l.flag&noflag != 0 {
+		return nil
+	}
+	s := fmt.Sprint(v...)
+	return l.output(calldepth+1, now, s)
+}
+
+// Outputf works like output but formats the output like Printf.
+func (l *Logger) Outputf(calldepth int, noflag int, format string, v ...interface{}) error {
+	now := time.Now()
+	l.mu.Lock()
+	defer l.mu.Unlock()
+	if l.flag&noflag != 0 {
+		return nil
+	}
+	s := fmt.Sprintf(format, v...)
+	return l.output(calldepth+1, now, s)
+}
+
+// Outputln works like output but formats the output like Println.
+func (l *Logger) Outputln(calldepth int, noflag int, v ...interface{}) error {
+	now := time.Now()
+	l.mu.Lock()
+	defer l.mu.Unlock()
+	if l.flag&noflag != 0 {
+		return nil
+	}
+	s := fmt.Sprintln(v...)
+	return l.output(calldepth+1, now, s)
+}
+
+// Panic prints the message like Print and calls panic. The printing
+// might be suppressed by the flag Lnopanic.
+func (l *Logger) Panic(v ...interface{}) {
+	l.Output(2, Lnopanic, v...)
+	s := fmt.Sprint(v...)
+	panic(s)
+}
+
+// Panic prints the message like Print and calls panic. The printing
+// might be suppressed by the flag Lnopanic.
+func Panic(v ...interface{}) {
+	std.Output(2, Lnopanic, v...)
+	s := fmt.Sprint(v...)
+	panic(s)
+}
+
+// Panicf prints the message like Printf and calls panic. The printing
+// might be suppressed by the flag Lnopanic.
+func (l *Logger) Panicf(format string, v ...interface{}) {
+	l.Outputf(2, Lnopanic, format, v...)
+	s := fmt.Sprintf(format, v...)
+	panic(s)
+}
+
+// Panicf prints the message like Printf and calls panic. The printing
+// might be suppressed by the flag Lnopanic.
+func Panicf(format string, v ...interface{}) {
+	std.Outputf(2, Lnopanic, format, v...)
+	s := fmt.Sprintf(format, v...)
+	panic(s)
+}
+
+// Panicln prints the message like Println and calls panic. The printing
+// might be suppressed by the flag Lnopanic.
+func (l *Logger) Panicln(v ...interface{}) {
+	l.Outputln(2, Lnopanic, v...)
+	s := fmt.Sprintln(v...)
+	panic(s)
+}
+
+// Panicln prints the message like Println and calls panic. The printing
+// might be suppressed by the flag Lnopanic.
+func Panicln(v ...interface{}) {
+	std.Outputln(2, Lnopanic, v...)
+	s := fmt.Sprintln(v...)
+	panic(s)
+}
+
+// Fatal prints the message like Print and calls os.Exit(1). The
+// printing might be suppressed by the flag Lnofatal.
+func (l *Logger) Fatal(v ...interface{}) {
+	l.Output(2, Lnofatal, v...)
+	os.Exit(1)
+}
+
+// Fatal prints the message like Print and calls os.Exit(1). The
+// printing might be suppressed by the flag Lnofatal.
+func Fatal(v ...interface{}) {
+	std.Output(2, Lnofatal, v...)
+	os.Exit(1)
+}
+
+// Fatalf prints the message like Printf and calls os.Exit(1). The
+// printing might be suppressed by the flag Lnofatal.
+func (l *Logger) Fatalf(format string, v ...interface{}) {
+	l.Outputf(2, Lnofatal, format, v...)
+	os.Exit(1)
+}
+
+// Fatalf prints the message like Printf and calls os.Exit(1). The
+// printing might be suppressed by the flag Lnofatal.
+func Fatalf(format string, v ...interface{}) {
+	std.Outputf(2, Lnofatal, format, v...)
+	os.Exit(1)
+}
+
+// Fatalln prints the message like Println and calls os.Exit(1). The
+// printing might be suppressed by the flag Lnofatal.
+func (l *Logger) Fatalln(format string, v ...interface{}) {
+	l.Outputln(2, Lnofatal, v...)
+	os.Exit(1)
+}
+
+// Fatalln prints the message like Println and calls os.Exit(1). The
+// printing might be suppressed by the flag Lnofatal.
+func Fatalln(format string, v ...interface{}) {
+	std.Outputln(2, Lnofatal, v...)
+	os.Exit(1)
+}
+
+// Warn prints the message like Print. The printing might be suppressed
+// by the flag Lnowarn.
+func (l *Logger) Warn(v ...interface{}) {
+	l.Output(2, Lnowarn, v...)
+}
+
+// Warn prints the message like Print. The printing might be suppressed
+// by the flag Lnowarn.
+func Warn(v ...interface{}) {
+	std.Output(2, Lnowarn, v...)
+}
+
+// Warnf prints the message like Printf. The printing might be suppressed
+// by the flag Lnowarn.
+func (l *Logger) Warnf(format string, v ...interface{}) {
+	l.Outputf(2, Lnowarn, format, v...)
+}
+
+// Warnf prints the message like Printf. The printing might be suppressed
+// by the flag Lnowarn.
+func Warnf(format string, v ...interface{}) {
+	std.Outputf(2, Lnowarn, format, v...)
+}
+
+// Warnln prints the message like Println. The printing might be suppressed
+// by the flag Lnowarn.
+func (l *Logger) Warnln(v ...interface{}) {
+	l.Outputln(2, Lnowarn, v...)
+}
+
+// Warnln prints the message like Println. The printing might be suppressed
+// by the flag Lnowarn.
+func Warnln(v ...interface{}) {
+	std.Outputln(2, Lnowarn, v...)
+}
+
+// Print prints the message like fmt.Print. The printing might be suppressed
+// by the flag Lnoprint.
+func (l *Logger) Print(v ...interface{}) {
+	l.Output(2, Lnoprint, v...)
+}
+
+// Print prints the message like fmt.Print. The printing might be suppressed
+// by the flag Lnoprint.
+func Print(v ...interface{}) {
+	std.Output(2, Lnoprint, v...)
+}
+
+// Printf prints the message like fmt.Printf. The printing might be suppressed
+// by the flag Lnoprint.
+func (l *Logger) Printf(format string, v ...interface{}) {
+	l.Outputf(2, Lnoprint, format, v...)
+}
+
+// Printf prints the message like fmt.Printf. The printing might be suppressed
+// by the flag Lnoprint.
+func Printf(format string, v ...interface{}) {
+	std.Outputf(2, Lnoprint, format, v...)
+}
+
+// Println prints the message like fmt.Println. The printing might be
+// suppressed by the flag Lnoprint.
+func (l *Logger) Println(v ...interface{}) {
+	l.Outputln(2, Lnoprint, v...)
+}
+
+// Println prints the message like fmt.Println. The printing might be
+// suppressed by the flag Lnoprint.
+func Println(v ...interface{}) {
+	std.Outputln(2, Lnoprint, v...)
+}
+
+// Debug prints the message like Print. The printing might be suppressed
+// by the flag Lnodebug.
+func (l *Logger) Debug(v ...interface{}) {
+	l.Output(2, Lnodebug, v...)
+}
+
+// Debug prints the message like Print. The printing might be suppressed
+// by the flag Lnodebug.
+func Debug(v ...interface{}) {
+	std.Output(2, Lnodebug, v...)
+}
+
+// Debugf prints the message like Printf. The printing might be suppressed
+// by the flag Lnodebug.
+func (l *Logger) Debugf(format string, v ...interface{}) {
+	l.Outputf(2, Lnodebug, format, v...)
+}
+
+// Debugf prints the message like Printf. The printing might be suppressed
+// by the flag Lnodebug.
+func Debugf(format string, v ...interface{}) {
+	std.Outputf(2, Lnodebug, format, v...)
+}
+
+// Debugln prints the message like Println. The printing might be suppressed
+// by the flag Lnodebug.
+func (l *Logger) Debugln(v ...interface{}) {
+	l.Outputln(2, Lnodebug, v...)
+}
+
+// Debugln prints the message like Println. The printing might be suppressed
+// by the flag Lnodebug.
+func Debugln(v ...interface{}) {
+	std.Outputln(2, Lnodebug, v...)
+}
+
+// Flags returns the current flags used by the logger.
+func (l *Logger) Flags() int {
+	l.mu.Lock()
+	defer l.mu.Unlock()
+	return l.flag
+}
+
+// Flags returns the current flags used by the standard logger.
+func Flags() int {
+	return std.Flags()
+}
+
+// SetFlags sets the flags of the logger.
+func (l *Logger) SetFlags(flag int) {
+	l.mu.Lock()
+	defer l.mu.Unlock()
+	l.flag = flag
+}
+
+// SetFlags sets the flags for the standard logger.
+func SetFlags(flag int) {
+	std.SetFlags(flag)
+}
+
+// Prefix returns the prefix used by the logger.
+func (l *Logger) Prefix() string {
+	l.mu.Lock()
+	defer l.mu.Unlock()
+	return l.prefix
+}
+
+// Prefix returns the prefix used by the standard logger of the package.
+func Prefix() string {
+	return std.Prefix()
+}
+
+// SetPrefix sets the prefix for the logger.
+func (l *Logger) SetPrefix(prefix string) {
+	l.mu.Lock()
+	defer l.mu.Unlock()
+	l.prefix = prefix
+}
+
+// SetPrefix sets the prefix of the standard logger of the package.
+func SetPrefix(prefix string) {
+	std.SetPrefix(prefix)
+}
+
+// SetOutput sets the output of the logger.
+func (l *Logger) SetOutput(w io.Writer) {
+	l.mu.Lock()
+	defer l.mu.Unlock()
+	l.out = w
+}
+
+// SetOutput sets the output for the standard logger of the package.
+func SetOutput(w io.Writer) {
+	std.SetOutput(w)
+}

vendor/github.com/ulikunitz/xz/lzma/bintree.go

@@ -0,0 +1,523 @@
+// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package lzma
+
+import (
+	"bufio"
+	"errors"
+	"fmt"
+	"io"
+	"unicode"
+)
+
+// node represents a node in the binary tree.
+type node struct {
+	// x is the search value
+	x uint32
+	// p parent node
+	p uint32
+	// l left child
+	l uint32
+	// r right child
+	r uint32
+}
+
+// wordLen is the number of bytes represented by the v field of a node.
+const wordLen = 4
+
+// binTree supports the identification of the next operation based on a
+// binary tree.
+//
+// Nodes will be identified by their index into the ring buffer.
+type binTree struct {
+	dict *encoderDict
+	// ring buffer of nodes
+	node []node
+	// absolute offset of the entry for the next node. Position 4
+	// byte larger.
+	hoff int64
+	// front position in the node ring buffer
+	front uint32
+	// index of the root node
+	root uint32
+	// current x value
+	x uint32
+	// preallocated array
+	data []byte
+}
+
+// null represents the nonexistent index. We can't use zero because it
+// would always exist or we would need to decrease the index for each
+// reference.
+const null uint32 = 1<<32 - 1
+
+// newBinTree initializes the binTree structure. The capacity defines
+// the size of the buffer and defines the maximum distance for which
+// matches will be found.
+func newBinTree(capacity int) (t *binTree, err error) {
+	if capacity < 1 {
+		return nil, errors.New(
+			"newBinTree: capacity must be larger than zero")
+	}
+	if int64(capacity) >= int64(null) {
+		return nil, errors.New(
+			"newBinTree: capacity must less 2^{32}-1")
+	}
+	t = &binTree{
+		node: make([]node, capacity),
+		hoff: -int64(wordLen),
+		root: null,
+		data: make([]byte, maxMatchLen),
+	}
+	return t, nil
+}
+
+func (t *binTree) SetDict(d *encoderDict) { t.dict = d }
+
+// WriteByte writes a single byte into the binary tree.
+func (t *binTree) WriteByte(c byte) error {
+	t.x = (t.x << 8) | uint32(c)
+	t.hoff++
+	if t.hoff < 0 {
+		return nil
+	}
+	v := t.front
+	if int64(v) < t.hoff {
+		// We are overwriting old nodes stored in the tree.
+		t.remove(v)
+	}
+	t.node[v].x = t.x
+	t.add(v)
+	t.front++
+	if int64(t.front) >= int64(len(t.node)) {
+		t.front = 0
+	}
+	return nil
+}
+
+// Writes writes a sequence of bytes into the binTree structure.
+func (t *binTree) Write(p []byte) (n int, err error) {
+	for _, c := range p {
+		t.WriteByte(c)
+	}
+	return len(p), nil
+}
+
+// add puts the node v into the tree. The node must not be part of the
+// tree before.
+func (t *binTree) add(v uint32) {
+	vn := &t.node[v]
+	// Set left and right to null indices.
+	vn.l, vn.r = null, null
+	// If the binary tree is empty make v the root.
+	if t.root == null {
+		t.root = v
+		vn.p = null
+		return
+	}
+	x := vn.x
+	p := t.root
+	// Search for the right leave link and add the new node.
+	for {
+		pn := &t.node[p]
+		if x <= pn.x {
+			if pn.l == null {
+				pn.l = v
+				vn.p = p
+				return
+			}
+			p = pn.l
+		} else {
+			if pn.r == null {
+				pn.r = v
+				vn.p = p
+				return
+			}
+			p = pn.r
+		}
+	}
+}
+
+// parent returns the parent node index of v and the pointer to v value
+// in the parent.
+func (t *binTree) parent(v uint32) (p uint32, ptr *uint32) {
+	if t.root == v {
+		return null, &t.root
+	}
+	p = t.node[v].p
+	if t.node[p].l == v {
+		ptr = &t.node[p].l
+	} else {
+		ptr = &t.node[p].r
+	}
+	return
+}
+
+// Remove node v.
+func (t *binTree) remove(v uint32) {
+	vn := &t.node[v]
+	p, ptr := t.parent(v)
+	l, r := vn.l, vn.r
+	if l == null {
+		// Move the right child up.
+		*ptr = r
+		if r != null {
+			t.node[r].p = p
+		}
+		return
+	}
+	if r == null {
+		// Move the left child up.
+		*ptr = l
+		t.node[l].p = p
+		return
+	}
+
+	// Search the in-order predecessor u.
+	un := &t.node[l]
+	ur := un.r
+	if ur == null {
+		// In order predecessor is l. Move it up.
+		un.r = r
+		t.node[r].p = l
+		un.p = p
+		*ptr = l
+		return
+	}
+	var u uint32
+	for {
+		// Look for the max value in the tree where l is root.
+		u = ur
+		ur = t.node[u].r
+		if ur == null {
+			break
+		}
+	}
+	// replace u with ul
+	un = &t.node[u]
+	ul := un.l
+	up := un.p
+	t.node[up].r = ul
+	if ul != null {
+		t.node[ul].p = up
+	}
+
+	// replace v by u
+	un.l, un.r = l, r
+	t.node[l].p = u
+	t.node[r].p = u
+	*ptr = u
+	un.p = p
+}
+
+// search looks for the node that have the value x or for the nodes that
+// brace it. The node highest in the tree with the value x will be
+// returned. All other nodes with the same value live in left subtree of
+// the returned node.
+func (t *binTree) search(v uint32, x uint32) (a, b uint32) {
+	a, b = null, null
+	if v == null {
+		return
+	}
+	for {
+		vn := &t.node[v]
+		if x <= vn.x {
+			if x == vn.x {
+				return v, v
+			}
+			b = v
+			if vn.l == null {
+				return
+			}
+			v = vn.l
+		} else {
+			a = v
+			if vn.r == null {
+				return
+			}
+			v = vn.r
+		}
+	}
+}
+
+// max returns the node with maximum value in the subtree with v as
+// root.
+func (t *binTree) max(v uint32) uint32 {
+	if v == null {
+		return null
+	}
+	for {
+		r := t.node[v].r
+		if r == null {
+			return v
+		}
+		v = r
+	}
+}
+
+// min returns the node with the minimum value in the subtree with v as
+// root.
+func (t *binTree) min(v uint32) uint32 {
+	if v == null {
+		return null
+	}
+	for {
+		l := t.node[v].l
+		if l == null {
+			return v
+		}
+		v = l
+	}
+}
+
+// pred returns the in-order predecessor of node v.
+func (t *binTree) pred(v uint32) uint32 {
+	if v == null {
+		return null
+	}
+	u := t.max(t.node[v].l)
+	if u != null {
+		return u
+	}
+	for {
+		p := t.node[v].p
+		if p == null {
+			return null
+		}
+		if t.node[p].r == v {
+			return p
+		}
+		v = p
+	}
+}
+
+// succ returns the in-order successor of node v.
+func (t *binTree) succ(v uint32) uint32 {
+	if v == null {
+		return null
+	}
+	u := t.min(t.node[v].r)
+	if u != null {
+		return u
+	}
+	for {
+		p := t.node[v].p
+		if p == null {
+			return null
+		}
+		if t.node[p].l == v {
+			return p
+		}
+		v = p
+	}
+}
+
+// xval converts the first four bytes of a into an 32-bit unsigned
+// integer in big-endian order.
+func xval(a []byte) uint32 {
+	var x uint32
+	switch len(a) {
+	default:
+		x |= uint32(a[3])
+		fallthrough
+	case 3:
+		x |= uint32(a[2]) << 8
+		fallthrough
+	case 2:
+		x |= uint32(a[1]) << 16
+		fallthrough
+	case 1:
+		x |= uint32(a[0]) << 24
+	case 0:
+	}
+	return x
+}
+
+// dumpX converts value x into a four-letter string.
+func dumpX(x uint32) string {
+	a := make([]byte, 4)
+	for i := 0; i < 4; i++ {
+		c := byte(x >> uint((3-i)*8))
+		if unicode.IsGraphic(rune(c)) {
+			a[i] = c
+		} else {
+			a[i] = '.'
+		}
+	}
+	return string(a)
+}
+
+// dumpNode writes a representation of the node v into the io.Writer.
+func (t *binTree) dumpNode(w io.Writer, v uint32, indent int) {
+	if v == null {
+		return
+	}
+
+	vn := &t.node[v]
+
+	t.dumpNode(w, vn.r, indent+2)
+
+	for i := 0; i < indent; i++ {
+		fmt.Fprint(w, " ")
+	}
+	if vn.p == null {
+		fmt.Fprintf(w, "node %d %q parent null\n", v, dumpX(vn.x))
+	} else {
+		fmt.Fprintf(w, "node %d %q parent %d\n", v, dumpX(vn.x), vn.p)
+	}
+
+	t.dumpNode(w, vn.l, indent+2)
+}
+
+// dump prints a representation of the binary tree into the writer.
+func (t *binTree) dump(w io.Writer) error {
+	bw := bufio.NewWriter(w)
+	t.dumpNode(bw, t.root, 0)
+	return bw.Flush()
+}
+
+func (t *binTree) distance(v uint32) int {
+	dist := int(t.front) - int(v)
+	if dist <= 0 {
+		dist += len(t.node)
+	}
+	return dist
+}
+
+type matchParams struct {
+	rep [4]uint32
+	// length when match will be accepted
+	nAccept int
+	// nodes to check
+	check int
+	// finish if length get shorter
+	stopShorter bool
+}
+
+func (t *binTree) match(m match, distIter func() (int, bool), p matchParams,
+) (r match, checked int, accepted bool) {
+	buf := &t.dict.buf
+	for {
+		if checked >= p.check {
+			return m, checked, true
+		}
+		dist, ok := distIter()
+		if !ok {
+			return m, checked, false
+		}
+		checked++
+		if m.n > 0 {
+			i := buf.rear - dist + m.n - 1
+			if i < 0 {
+				i += len(buf.data)
+			} else if i >= len(buf.data) {
+				i -= len(buf.data)
+			}
+			if buf.data[i] != t.data[m.n-1] {
+				if p.stopShorter {
+					return m, checked, false
+				}
+				continue
+			}
+		}
+		n := buf.matchLen(dist, t.data)
+		switch n {
+		case 0:
+			if p.stopShorter {
+				return m, checked, false
+			}
+			continue
+		case 1:
+			if uint32(dist-minDistance) != p.rep[0] {
+				continue
+			}
+		}
+		if n < m.n || (n == m.n && int64(dist) >= m.distance) {
+			continue
+		}
+		m = match{int64(dist), n}
+		if n >= p.nAccept {
+			return m, checked, true
+		}
+	}
+}
+
+func (t *binTree) NextOp(rep [4]uint32) operation {
+	// retrieve maxMatchLen data
+	n, _ := t.dict.buf.Peek(t.data[:maxMatchLen])
+	if n == 0 {
+		panic("no data in buffer")
+	}
+	t.data = t.data[:n]
+
+	var (
+		m                  match
+		x, u, v            uint32
+		iterPred, iterSucc func() (int, bool)
+	)
+	p := matchParams{
+		rep:     rep,
+		nAccept: maxMatchLen,
+		check:   32,
+	}
+	i := 4
+	iterSmall := func() (dist int, ok bool) {
+		i--
+		if i <= 0 {
+			return 0, false
+		}
+		return i, true
+	}
+	m, checked, accepted := t.match(m, iterSmall, p)
+	if accepted {
+		goto end
+	}
+	p.check -= checked
+	x = xval(t.data)
+	u, v = t.search(t.root, x)
+	if u == v && len(t.data) == 4 {
+		iter := func() (dist int, ok bool) {
+			if u == null {
+				return 0, false
+			}
+			dist = t.distance(u)
+			u, v = t.search(t.node[u].l, x)
+			if u != v {
+				u = null
+			}
+			return dist, true
+		}
+		m, _, _ = t.match(m, iter, p)
+		goto end
+	}
+	p.stopShorter = true
+	iterSucc = func() (dist int, ok bool) {
+		if v == null {
+			return 0, false
+		}
+		dist = t.distance(v)
+		v = t.succ(v)
+		return dist, true
+	}
+	m, checked, accepted = t.match(m, iterSucc, p)
+	if accepted {
+		goto end
+	}
+	p.check -= checked
+	iterPred = func() (dist int, ok bool) {
+		if u == null {
+			return 0, false
+		}
+		dist = t.distance(u)
+		u = t.pred(u)
+		return dist, true
+	}
+	m, _, _ = t.match(m, iterPred, p)
+end:
+	if m.n == 0 {
+		return lit{t.data[0]}
+	}
+	return m
+}

vendor/github.com/ulikunitz/xz/lzma/bintree_test.go

@@ -0,0 +1,107 @@
+// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package lzma
+
+import (
+	"bytes"
+	"io"
+	"math/rand"
+	"strings"
+	"testing"
+
+	"github.com/ulikunitz/xz/internal/randtxt"
+)
+
+func TestBinTree_Find(t *testing.T) {
+	bt, err := newBinTree(30)
+	if err != nil {
+		t.Fatal(err)
+	}
+	const s = "Klopp feiert mit Liverpool seinen hoechsten SiegSieg"
+	n, err := io.WriteString(bt, s)
+	if err != nil {
+		t.Fatalf("WriteString error %s", err)
+	}
+	if n != len(s) {
+		t.Fatalf("WriteString returned %d; want %d", n, len(s))
+	}
+
+	/* dump info writes the complete tree
+	if err = bt.dump(os.Stdout); err != nil {
+		t.Fatalf("bt.dump error %s", err)
+	}
+	*/
+
+	tests := []string{"Sieg", "Sieb", "Simu"}
+	for _, c := range tests {
+		x := xval([]byte(c))
+		a, b := bt.search(bt.root, x)
+		t.Logf("%q: a, b == %d, %d", c, a, b)
+	}
+}
+
+func TestBinTree_PredSucc(t *testing.T) {
+	bt, err := newBinTree(30)
+	if err != nil {
+		t.Fatal(err)
+	}
+	const s = "Klopp feiert mit Liverpool seinen hoechsten Sieg."
+	n, err := io.WriteString(bt, s)
+	if err != nil {
+		t.Fatalf("WriteString error %s", err)
+	}
+	if n != len(s) {
+		t.Fatalf("WriteString returned %d; want %d", n, len(s))
+	}
+	for v := bt.min(bt.root); v != null; v = bt.succ(v) {
+		t.Log(dumpX(bt.node[v].x))
+	}
+	t.Log("")
+	for v := bt.max(bt.root); v != null; v = bt.pred(v) {
+		t.Log(dumpX(bt.node[v].x))
+	}
+}
+
+func TestBinTree_Cycle(t *testing.T) {
+	buf := new(bytes.Buffer)
+	w, err := Writer2Config{
+		DictCap: 4096,
+		Matcher: BinaryTree,
+	}.NewWriter2(buf)
+	if err != nil {
+		t.Fatalf("NewWriter error %s", err)
+	}
+	// const txtlen = 1024
+	const txtlen = 10000
+	io.CopyN(buf, randtxt.NewReader(rand.NewSource(42)), txtlen)
+	txt := buf.String()
+	buf.Reset()
+	n, err := io.Copy(w, strings.NewReader(txt))
+	if err != nil {
+		t.Fatalf("Compressing copy error %s", err)
+	}
+	if n != txtlen {
+		t.Fatalf("Compressing data length %d; want %d", n, txtlen)
+	}
+	if err = w.Close(); err != nil {
+		t.Fatalf("w.Close error %s", err)
+	}
+	t.Logf("buf.Len() %d", buf.Len())
+	r, err := Reader2Config{DictCap: 4096}.NewReader2(buf)
+	if err != nil {
+		t.Fatalf("NewReader error %s", err)
+	}
+	out := new(bytes.Buffer)
+	n, err = io.Copy(out, r)
+	if err != nil {
+		t.Fatalf("Decompressing copy error %s after %d bytes", err, n)
+	}
+	if n != txtlen {
+		t.Fatalf("Decompression data length %d; want %d", n, txtlen)
+	}
+	if txt != out.String() {
+		t.Fatal("decompressed data differs from original")
+	}
+}

vendor/github.com/ulikunitz/xz/lzma/bitops.go

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

vendor/github.com/ulikunitz/xz/lzma/breader.go

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

vendor/github.com/ulikunitz/xz/lzma/buffer.go

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

vendor/github.com/ulikunitz/xz/lzma/buffer_test.go

@@ -0,0 +1,230 @@
+// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package lzma
+
+import (
+	"bytes"
+	"io"
+	"testing"
+)
+
+func TestBuffer_Write(t *testing.T) {
+	buf := newBuffer(10)
+	b := []byte("1234567890")
+	for i := range b {
+		n, err := buf.Write(b[i : i+1])
+		if err != nil {
+			t.Fatalf("buf.Write(b[%d:%d]) error %s", i, i+1, err)
+		}
+		if n != 1 {
+			t.Fatalf("buf.Write(b[%d:%d]) returned %d; want %d",
+				i, i+1, n, 1)
+		}
+	}
+	const c = 8
+	n, err := buf.Discard(c)
+	if err != nil {
+		t.Fatalf("Discard error %s", err)
+	}
+	if n != c {
+		t.Fatalf("Discard returned %d; want %d", n, c)
+	}
+	n, err = buf.Write(b)
+	if err == nil {
+		t.Fatalf("Write length exceed returned no error; n %d", n)
+	}
+	if n != c {
+		t.Fatalf("Write length exceeding returned %d; want %d", n, c)
+	}
+	n, err = buf.Discard(4)
+	if err != nil {
+		t.Fatalf("Discard error %s", err)
+	}
+	if n != 4 {
+		t.Fatalf("Discard returned %d; want %d", n, 4)
+	}
+	n, err = buf.Write(b[:3])
+	if err != nil {
+		t.Fatalf("buf.Write(b[:3]) error %s; n %d", err, n)
+	}
+	if n != 3 {
+		t.Fatalf("buf.Write(b[:3]) returned %d; want %d", n, 3)
+	}
+}
+
+func TestBuffer_Buffered_Available(t *testing.T) {
+	buf := newBuffer(19)
+	b := []byte("0123456789")
+	var err error
+	if _, err = buf.Write(b); err != nil {
+		t.Fatalf("buf.Write(b) error %s", err)
+	}
+	if n := buf.Buffered(); n != 10 {
+		t.Fatalf("buf.Buffered() returns %d; want %d", n, 10)
+	}
+	if _, err = buf.Discard(8); err != nil {
+		t.Fatalf("buf.Discard(8) error %s", err)
+	}
+	if _, err = buf.Write(b[:7]); err != nil {
+		t.Fatalf("buf.Write(b[:7]) error %s", err)
+	}
+	if n := buf.Buffered(); n != 9 {
+		t.Fatalf("buf.Buffered() returns %d; want %d", n, 9)
+	}
+}
+
+func TestBuffer_Read(t *testing.T) {
+	buf := newBuffer(10)
+	b := []byte("0123456789")
+	var err error
+	if _, err = buf.Write(b); err != nil {
+		t.Fatalf("buf.Write(b) error %s", err)
+	}
+	p := make([]byte, 8)
+	n, err := buf.Read(p)
+	if err != nil {
+		t.Fatalf("buf.Read(p) error %s", err)
+	}
+	if n != len(p) {
+		t.Fatalf("buf.Read(p) returned %d; want %d", n, len(p))
+	}
+	if !bytes.Equal(p, b[:8]) {
+		t.Fatalf("buf.Read(p) put %s into p; want %s", p, b[:8])
+	}
+	if _, err = buf.Write(b[:7]); err != nil {
+		t.Fatalf("buf.Write(b[:7]) error %s", err)
+	}
+	q := make([]byte, 7)
+	n, err = buf.Read(q)
+	if err != nil {
+		t.Fatalf("buf.Read(q) error %s", err)
+	}
+	if n != len(q) {
+		t.Fatalf("buf.Read(q) returns %d; want %d", n, len(q))
+	}
+	c := []byte("8901234")
+	if !bytes.Equal(q, c) {
+		t.Fatalf("buf.Read(q) put %s into q; want %s", q, c)
+	}
+	if _, err := buf.Write(b[7:]); err != nil {
+		t.Fatalf("buf.Write(b[7:]) error %s", err)
+	}
+	if _, err := buf.Write(b[:2]); err != nil {
+		t.Fatalf("buf.Write(b[:2]) error %s", err)
+	}
+	t.Logf("buf.rear %d buf.front %d", buf.rear, buf.front)
+	r := make([]byte, 2)
+	n, err = buf.Read(r)
+	if err != nil {
+		t.Fatalf("buf.Read(r) error %s", err)
+	}
+	if n != len(r) {
+		t.Fatalf("buf.Read(r) returns %d; want %d", n, len(r))
+	}
+	d := []byte("56")
+	if !bytes.Equal(r, d) {
+		t.Fatalf("buf.Read(r) put %s into r; want %s", r, d)
+	}
+}
+
+func TestBuffer_Discard(t *testing.T) {
+	buf := newBuffer(10)
+	b := []byte("0123456789")
+	var err error
+	if _, err = buf.Write(b); err != nil {
+		t.Fatalf("buf.Write(b) error %s", err)
+	}
+	n, err := buf.Discard(11)
+	if err == nil {
+		t.Fatalf("buf.Discard(11) didn't return error")
+	}
+	if n != 10 {
+		t.Fatalf("buf.Discard(11) returned %d; want %d", n, 10)
+	}
+	if _, err := buf.Write(b); err != nil {
+		t.Fatalf("buf.Write(b) #2 error %s", err)
+	}
+	n, err = buf.Discard(10)
+	if err != nil {
+		t.Fatalf("buf.Discard(10) error %s", err)
+	}
+	if n != 10 {
+		t.Fatalf("buf.Discard(11) returned %d; want %d", n, 10)
+	}
+	if _, err := buf.Write(b[:4]); err != nil {
+		t.Fatalf("buf.Write(b[:4]) error %s", err)
+	}
+	n, err = buf.Discard(1)
+	if err != nil {
+		t.Fatalf("buf.Discard(1) error %s", err)
+	}
+	if n != 1 {
+		t.Fatalf("buf.Discard(1) returned %d; want %d", n, 1)
+	}
+}
+
+func TestBuffer_Discard_error(t *testing.T) {
+	buf := newBuffer(10)
+	n, err := buf.Discard(-1)
+	if err == nil {
+		t.Fatal("buf.Discard(-1) didn't return an error")
+	}
+	if n != 0 {
+		t.Fatalf("buf.Discard(-1) returned %d; want %d", n, 0)
+	}
+}
+
+func TestPrefixLen(t *testing.T) {
+	tests := []struct {
+		a, b []byte
+		k    int
+	}{
+		{[]byte("abcde"), []byte("abc"), 3},
+		{[]byte("abc"), []byte("uvw"), 0},
+		{[]byte(""), []byte("uvw"), 0},
+		{[]byte("abcde"), []byte("abcuvw"), 3},
+	}
+	for _, c := range tests {
+		k := prefixLen(c.a, c.b)
+		if k != c.k {
+			t.Errorf("prefixLen(%q,%q) returned %d; want %d",
+				c.a, c.b, k, c.k)
+		}
+		k = prefixLen(c.b, c.a)
+		if k != c.k {
+			t.Errorf("prefixLen(%q,%q) returned %d; want %d",
+				c.b, c.a, k, c.k)
+		}
+	}
+}
+
+func TestMatchLen(t *testing.T) {
+	buf := newBuffer(13)
+	const s = "abcaba"
+	_, err := io.WriteString(buf, s)
+	if err != nil {
+		t.Fatalf("WriteString error %s", err)
+	}
+	_, err = io.WriteString(buf, s)
+	if err != nil {
+		t.Fatalf("WriteString error %s", err)
+	}
+	if _, err = buf.Discard(12); err != nil {
+		t.Fatalf("buf.Discard(6) error %s", err)
+	}
+	_, err = io.WriteString(buf, s)
+	if err != nil {
+		t.Fatalf("WriteString error %s", err)
+	}
+	tests := []struct{ d, n int }{{1, 1}, {3, 2}, {6, 6}, {5, 0}, {2, 0}}
+	for _, c := range tests {
+		n := buf.matchLen(c.d, []byte(s))
+		if n != c.n {
+			t.Errorf(
+				"MatchLen(%d,[]byte(%q)) returned %d; want %d",
+				c.d, s, n, c.n)
+		}
+	}
+}

vendor/github.com/ulikunitz/xz/lzma/bytewriter.go

@@ -0,0 +1,37 @@
+// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package lzma
+
+import (
+	"errors"
+	"io"
+)
+
+// ErrLimit indicates that the limit of the LimitedByteWriter has been
+// reached.
+var ErrLimit = errors.New("limit reached")
+
+// LimitedByteWriter provides a byte writer that can be written until a
+// limit is reached. The field N provides the number of remaining
+// bytes.
+type LimitedByteWriter struct {
+	BW io.ByteWriter
+	N  int64
+}
+
+// WriteByte writes a single byte to the limited byte writer. It returns
+// ErrLimit if the limit has been reached. If the byte is successfully
+// written the field N of the LimitedByteWriter will be decremented by
+// one.
+func (l *LimitedByteWriter) WriteByte(c byte) error {
+	if l.N <= 0 {
+		return ErrLimit
+	}
+	if err := l.BW.WriteByte(c); err != nil {
+		return err
+	}
+	l.N--
+	return nil
+}

vendor/github.com/ulikunitz/xz/lzma/decoder.go

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

vendor/github.com/ulikunitz/xz/lzma/decoder_test.go

@@ -0,0 +1,59 @@
+// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package lzma
+
+import (
+	"bufio"
+	"io"
+	"io/ioutil"
+	"os"
+	"testing"
+)
+
+func TestDecoder(t *testing.T) {
+	filename := "fox.lzma"
+	want := "The quick brown fox jumps over the lazy dog.\n"
+	for i := 0; i < 2; i++ {
+		f, err := os.Open(filename)
+		if err != nil {
+			t.Fatalf("os.Open(%q) error %s", filename, err)
+		}
+		p := make([]byte, 13)
+		_, err = io.ReadFull(f, p)
+		if err != nil {
+			t.Fatalf("io.ReadFull error %s", err)
+		}
+		props, err := PropertiesForCode(p[0])
+		if err != nil {
+			t.Fatalf("p[0] error %s", err)
+		}
+		state := newState(props)
+		const capacity = 0x800000
+		dict, err := newDecoderDict(capacity)
+		if err != nil {
+			t.Fatalf("newDecoderDict: error %s", err)
+		}
+		size := int64(-1)
+		if i > 0 {
+			size = int64(len(want))
+		}
+		br := bufio.NewReader(f)
+		r, err := newDecoder(br, state, dict, size)
+		if err != nil {
+			t.Fatalf("newDecoder error %s", err)
+		}
+		bytes, err := ioutil.ReadAll(r)
+		if err != nil {
+			t.Fatalf("[%d] ReadAll error %s", i, err)
+		}
+		if err = f.Close(); err != nil {
+			t.Fatalf("Close error %s", err)
+		}
+		got := string(bytes)
+		if got != want {
+			t.Fatalf("read %q; but want %q", got, want)
+		}
+	}
+}

vendor/github.com/ulikunitz/xz/lzma/decoderdict.go

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

vendor/github.com/ulikunitz/xz/lzma/decoderdict_test.go

@@ -0,0 +1,33 @@
+// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package lzma
+
+import (
+	"fmt"
+	"testing"
+)
+
+func peek(d *decoderDict) []byte {
+	p := make([]byte, d.buffered())
+	k, err := d.peek(p)
+	if err != nil {
+		panic(fmt.Errorf("peek: "+
+			"Read returned unexpected error %s", err))
+	}
+	if k != len(p) {
+		panic(fmt.Errorf("peek: "+
+			"Read returned %d; wanted %d", k, len(p)))
+	}
+	return p
+}
+
+func TestNewDecoderDict(t *testing.T) {
+	if _, err := newDecoderDict(0); err == nil {
+		t.Fatalf("no error for zero dictionary capacity")
+	}
+	if _, err := newDecoderDict(8); err != nil {
+		t.Fatalf("error %s", err)
+	}
+}

vendor/github.com/ulikunitz/xz/lzma/directcodec.go

@@ -0,0 +1,49 @@
+// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package lzma
+
+import "fmt"
+
+// directCodec allows the encoding and decoding of values with a fixed number
+// of bits. The number of bits must be in the range [1,32].
+type directCodec byte
+
+// makeDirectCodec creates a directCodec. The function panics if the number of
+// bits is not in the range [1,32].
+func makeDirectCodec(bits int) directCodec {
+	if !(1 <= bits && bits <= 32) {
+		panic(fmt.Errorf("bits=%d out of range", bits))
+	}
+	return directCodec(bits)
+}
+
+// Bits returns the number of bits supported by this codec.
+func (dc directCodec) Bits() int {
+	return int(dc)
+}
+
+// Encode uses the range encoder to encode a value with the fixed number of
+// bits. The most-significant bit is encoded first.
+func (dc directCodec) Encode(e *rangeEncoder, v uint32) error {
+	for i := int(dc) - 1; i >= 0; i-- {
+		if err := e.DirectEncodeBit(v >> uint(i)); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// Decode uses the range decoder to decode a value with the given number of
+// given bits. The most-significant bit is decoded first.
+func (dc directCodec) Decode(d *rangeDecoder) (v uint32, err error) {
+	for i := int(dc) - 1; i >= 0; i-- {
+		x, err := d.DirectDecodeBit()
+		if err != nil {
+			return 0, err
+		}
+		v = (v << 1) | x
+	}
+	return v, nil
+}

vendor/github.com/ulikunitz/xz/lzma/distcodec.go

@@ -0,0 +1,156 @@
+// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package lzma
+
+// Constants used by the distance codec.
+const (
+	// minimum supported distance
+	minDistance = 1
+	// maximum supported distance, value is used for the eos marker.
+	maxDistance = 1 << 32
+	// number of the supported len states
+	lenStates = 4
+	// start for the position models
+	startPosModel = 4
+	// first index with align bits support
+	endPosModel = 14
+	// bits for the position slots
+	posSlotBits = 6
+	// number of align bits
+	alignBits = 4
+	// maximum position slot
+	maxPosSlot = 63
+)
+
+// distCodec provides encoding and decoding of distance values.
+type distCodec struct {
+	posSlotCodecs [lenStates]treeCodec
+	posModel      [endPosModel - startPosModel]treeReverseCodec
+	alignCodec    treeReverseCodec
+}
+
+// deepcopy initializes dc as deep copy of the source.
+func (dc *distCodec) deepcopy(src *distCodec) {
+	if dc == src {
+		return
+	}
+	for i := range dc.posSlotCodecs {
+		dc.posSlotCodecs[i].deepcopy(&src.posSlotCodecs[i])
+	}
+	for i := range dc.posModel {
+		dc.posModel[i].deepcopy(&src.posModel[i])
+	}
+	dc.alignCodec.deepcopy(&src.alignCodec)
+}
+
+// distBits returns the number of bits required to encode dist.
+func distBits(dist uint32) int {
+	if dist < startPosModel {
+		return 6
+	}
+	// slot s > 3, dist d
+	// s = 2(bits(d)-1) + bit(d, bits(d)-2)
+	// s>>1 = bits(d)-1
+	// bits(d) = 32-nlz32(d)
+	// s>>1=31-nlz32(d)
+	// n = 5 + (s>>1) = 36 - nlz32(d)
+	return 36 - nlz32(dist)
+}
+
+// newDistCodec creates a new distance codec.
+func (dc *distCodec) init() {
+	for i := range dc.posSlotCodecs {
+		dc.posSlotCodecs[i] = makeTreeCodec(posSlotBits)
+	}
+	for i := range dc.posModel {
+		posSlot := startPosModel + i
+		bits := (posSlot >> 1) - 1
+		dc.posModel[i] = makeTreeReverseCodec(bits)
+	}
+	dc.alignCodec = makeTreeReverseCodec(alignBits)
+}
+
+// lenState converts the value l to a supported lenState value.
+func lenState(l uint32) uint32 {
+	if l >= lenStates {
+		l = lenStates - 1
+	}
+	return l
+}
+
+// Encode encodes the distance using the parameter l. Dist can have values from
+// the full range of uint32 values. To get the distance offset the actual match
+// distance has to be decreased by 1. A distance offset of 0xffffffff (eos)
+// indicates the end of the stream.
+func (dc *distCodec) Encode(e *rangeEncoder, dist uint32, l uint32) (err error) {
+	// Compute the posSlot using nlz32
+	var posSlot uint32
+	var bits uint32
+	if dist < startPosModel {
+		posSlot = dist
+	} else {
+		bits = uint32(30 - nlz32(dist))
+		posSlot = startPosModel - 2 + (bits << 1)
+		posSlot += (dist >> uint(bits)) & 1
+	}
+
+	if err = dc.posSlotCodecs[lenState(l)].Encode(e, posSlot); err != nil {
+		return
+	}
+
+	switch {
+	case posSlot < startPosModel:
+		return nil
+	case posSlot < endPosModel:
+		tc := &dc.posModel[posSlot-startPosModel]
+		return tc.Encode(dist, e)
+	}
+	dic := directCodec(bits - alignBits)
+	if err = dic.Encode(e, dist>>alignBits); err != nil {
+		return
+	}
+	return dc.alignCodec.Encode(dist, e)
+}
+
+// Decode decodes the distance offset using the parameter l. The dist value
+// 0xffffffff (eos) indicates the end of the stream. Add one to the distance
+// offset to get the actual match distance.
+func (dc *distCodec) Decode(d *rangeDecoder, l uint32) (dist uint32, err error) {
+	posSlot, err := dc.posSlotCodecs[lenState(l)].Decode(d)
+	if err != nil {
+		return
+	}
+
+	// posSlot equals distance
+	if posSlot < startPosModel {
+		return posSlot, nil
+	}
+
+	// posSlot uses the individual models
+	bits := (posSlot >> 1) - 1
+	dist = (2 | (posSlot & 1)) << bits
+	var u uint32
+	if posSlot < endPosModel {
+		tc := &dc.posModel[posSlot-startPosModel]
+		if u, err = tc.Decode(d); err != nil {
+			return 0, err
+		}
+		dist += u
+		return dist, nil
+	}
+
+	// posSlots use direct encoding and a single model for the four align
+	// bits.
+	dic := directCodec(bits - alignBits)
+	if u, err = dic.Decode(d); err != nil {
+		return 0, err
+	}
+	dist += u << alignBits
+	if u, err = dc.alignCodec.Decode(d); err != nil {
+		return 0, err
+	}
+	dist += u
+	return dist, nil
+}

vendor/github.com/ulikunitz/xz/lzma/encoder.go

@@ -0,0 +1,268 @@
+// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package lzma
+
+import (
+	"fmt"
+	"io"
+)
+
+// opLenMargin provides the upper limit of the number of bytes required
+// to encode a single operation.
+const opLenMargin = 10
+
+// compressFlags control the compression process.
+type compressFlags uint32
+
+// Values for compressFlags.
+const (
+	// all data should be compressed, even if compression is not
+	// optimal.
+	all compressFlags = 1 << iota
+)
+
+// encoderFlags provide the flags for an encoder.
+type encoderFlags uint32
+
+// Flags for the encoder.
+const (
+	// eosMarker requests an EOS marker to be written.
+	eosMarker encoderFlags = 1 << iota
+)
+
+// Encoder compresses data buffered in the encoder dictionary and writes
+// it into a byte writer.
+type encoder struct {
+	dict  *encoderDict
+	state *state
+	re    *rangeEncoder
+	start int64
+	// generate eos marker
+	marker bool
+	limit  bool
+	margin int
+}
+
+// newEncoder creates a new encoder. If the byte writer must be
+// limited use LimitedByteWriter provided by this package. The flags
+// argument supports the eosMarker flag, controlling whether a
+// terminating end-of-stream marker must be written.
+func newEncoder(bw io.ByteWriter, state *state, dict *encoderDict,
+	flags encoderFlags) (e *encoder, err error) {
+
+	re, err := newRangeEncoder(bw)
+	if err != nil {
+		return nil, err
+	}
+	e = &encoder{
+		dict:   dict,
+		state:  state,
+		re:     re,
+		marker: flags&eosMarker != 0,
+		start:  dict.Pos(),
+		margin: opLenMargin,
+	}
+	if e.marker {
+		e.margin += 5
+	}
+	return e, nil
+}
+
+// Write writes the bytes from p into the dictionary. If not enough
+// space is available the data in the dictionary buffer will be
+// compressed to make additional space available. If the limit of the
+// underlying writer has been reached ErrLimit will be returned.
+func (e *encoder) Write(p []byte) (n int, err error) {
+	for {
+		k, err := e.dict.Write(p[n:])
+		n += k
+		if err == ErrNoSpace {
+			if err = e.compress(0); err != nil {
+				return n, err
+			}
+			continue
+		}
+		return n, err
+	}
+}
+
+// Reopen reopens the encoder with a new byte writer.
+func (e *encoder) Reopen(bw io.ByteWriter) error {
+	var err error
+	if e.re, err = newRangeEncoder(bw); err != nil {
+		return err
+	}
+	e.start = e.dict.Pos()
+	e.limit = false
+	return nil
+}
+
+// writeLiteral writes a literal into the LZMA stream
+func (e *encoder) writeLiteral(l lit) error {
+	var err error
+	state, state2, _ := e.state.states(e.dict.Pos())
+	if err = e.state.isMatch[state2].Encode(e.re, 0); err != nil {
+		return err
+	}
+	litState := e.state.litState(e.dict.ByteAt(1), e.dict.Pos())
+	match := e.dict.ByteAt(int(e.state.rep[0]) + 1)
+	err = e.state.litCodec.Encode(e.re, l.b, state, match, litState)
+	if err != nil {
+		return err
+	}
+	e.state.updateStateLiteral()
+	return nil
+}
+
+// iverson implements the Iverson operator as proposed by Donald Knuth in his
+// book Concrete Mathematics.
+func iverson(ok bool) uint32 {
+	if ok {
+		return 1
+	}
+	return 0
+}
+
+// writeMatch writes a repetition operation into the operation stream
+func (e *encoder) writeMatch(m match) error {
+	var err error
+	if !(minDistance <= m.distance && m.distance <= maxDistance) {
+		panic(fmt.Errorf("match distance %d out of range", m.distance))
+	}
+	dist := uint32(m.distance - minDistance)
+	if !(minMatchLen <= m.n && m.n <= maxMatchLen) &&
+		!(dist == e.state.rep[0] && m.n == 1) {
+		panic(fmt.Errorf(
+			"match length %d out of range; dist %d rep[0] %d",
+			m.n, dist, e.state.rep[0]))
+	}
+	state, state2, posState := e.state.states(e.dict.Pos())
+	if err = e.state.isMatch[state2].Encode(e.re, 1); err != nil {
+		return err
+	}
+	g := 0
+	for ; g < 4; g++ {
+		if e.state.rep[g] == dist {
+			break
+		}
+	}
+	b := iverson(g < 4)
+	if err = e.state.isRep[state].Encode(e.re, b); err != nil {
+		return err
+	}
+	n := uint32(m.n - minMatchLen)
+	if b == 0 {
+		// simple match
+		e.state.rep[3], e.state.rep[2], e.state.rep[1], e.state.rep[0] =
+			e.state.rep[2], e.state.rep[1], e.state.rep[0], dist
+		e.state.updateStateMatch()
+		if err = e.state.lenCodec.Encode(e.re, n, posState); err != nil {
+			return err
+		}
+		return e.state.distCodec.Encode(e.re, dist, n)
+	}
+	b = iverson(g != 0)
+	if err = e.state.isRepG0[state].Encode(e.re, b); err != nil {
+		return err
+	}
+	if b == 0 {
+		// g == 0
+		b = iverson(m.n != 1)
+		if err = e.state.isRepG0Long[state2].Encode(e.re, b); err != nil {
+			return err
+		}
+		if b == 0 {
+			e.state.updateStateShortRep()
+			return nil
+		}
+	} else {
+		// g in {1,2,3}
+		b = iverson(g != 1)
+		if err = e.state.isRepG1[state].Encode(e.re, b); err != nil {
+			return err
+		}
+		if b == 1 {
+			// g in {2,3}
+			b = iverson(g != 2)
+			err = e.state.isRepG2[state].Encode(e.re, b)
+			if err != nil {
+				return err
+			}
+			if b == 1 {
+				e.state.rep[3] = e.state.rep[2]
+			}
+			e.state.rep[2] = e.state.rep[1]
+		}
+		e.state.rep[1] = e.state.rep[0]
+		e.state.rep[0] = dist
+	}
+	e.state.updateStateRep()
+	return e.state.repLenCodec.Encode(e.re, n, posState)
+}
+
+// writeOp writes a single operation to the range encoder. The function
+// checks whether there is enough space available to close the LZMA
+// stream.
+func (e *encoder) writeOp(op operation) error {
+	if e.re.Available() < int64(e.margin) {
+		return ErrLimit
+	}
+	switch x := op.(type) {
+	case lit:
+		return e.writeLiteral(x)
+	case match:
+		return e.writeMatch(x)
+	default:
+		panic("unexpected operation")
+	}
+}
+
+// compress compressed data from the dictionary buffer. If the flag all
+// is set, all data in the dictionary buffer will be compressed. The
+// function returns ErrLimit if the underlying writer has reached its
+// limit.
+func (e *encoder) compress(flags compressFlags) error {
+	n := 0
+	if flags&all == 0 {
+		n = maxMatchLen - 1
+	}
+	d := e.dict
+	m := d.m
+	for d.Buffered() > n {
+		op := m.NextOp(e.state.rep)
+		if err := e.writeOp(op); err != nil {
+			return err
+		}
+		d.Discard(op.Len())
+	}
+	return nil
+}
+
+// eosMatch is a pseudo operation that indicates the end of the stream.
+var eosMatch = match{distance: maxDistance, n: minMatchLen}
+
+// Close terminates the LZMA stream. If requested the end-of-stream
+// marker will be written. If the byte writer limit has been or will be
+// reached during compression of the remaining data in the buffer the
+// LZMA stream will be closed and data will remain in the buffer.
+func (e *encoder) Close() error {
+	err := e.compress(all)
+	if err != nil && err != ErrLimit {
+		return err
+	}
+	if e.marker {
+		if err := e.writeMatch(eosMatch); err != nil {
+			return err
+		}
+	}
+	err = e.re.Close()
+	return err
+}
+
+// Compressed returns the number bytes of the input data that been
+// compressed.
+func (e *encoder) Compressed() int64 {
+	return e.dict.Pos() - e.start
+}

vendor/github.com/ulikunitz/xz/lzma/encoder_test.go

@@ -0,0 +1,151 @@
+// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package lzma
+
+import (
+	"bytes"
+	"io"
+	"io/ioutil"
+	"math/rand"
+	"testing"
+
+	"github.com/ulikunitz/xz/internal/randtxt"
+)
+
+var testString = `LZMA decoder test example
+=========================
+! LZMA ! Decoder ! TEST !
+=========================
+! TEST ! LZMA ! Decoder !
+=========================
+---- Test Line 1 --------
+=========================
+---- Test Line 2 --------
+=========================
+=== End of test file ====
+=========================
+`
+
+func cycle(t *testing.T, n int) {
+	t.Logf("cycle(t,%d)", n)
+	if n > len(testString) {
+		t.Fatalf("cycle: n=%d larger than len(testString)=%d", n,
+			len(testString))
+	}
+	const dictCap = MinDictCap
+	m, err := newHashTable(dictCap, 4)
+	if err != nil {
+		t.Fatal(err)
+	}
+	encoderDict, err := newEncoderDict(dictCap, dictCap+1024, m)
+	if err != nil {
+		t.Fatal(err)
+	}
+	props := Properties{2, 0, 2}
+	if err := props.verify(); err != nil {
+		t.Fatalf("properties error %s", err)
+	}
+	state := newState(props)
+	var buf bytes.Buffer
+	w, err := newEncoder(&buf, state, encoderDict, eosMarker)
+	if err != nil {
+		t.Fatalf("newEncoder error %s", err)
+	}
+	orig := []byte(testString)[:n]
+	t.Logf("len(orig) %d", len(orig))
+	k, err := w.Write(orig)
+	if err != nil {
+		t.Fatalf("w.Write error %s", err)
+	}
+	if k != len(orig) {
+		t.Fatalf("w.Write returned %d; want %d", k, len(orig))
+	}
+	if err = w.Close(); err != nil {
+		t.Fatalf("w.Close error %s", err)
+	}
+	t.Logf("buf.Len() %d len(orig) %d", buf.Len(), len(orig))
+	decoderDict, err := newDecoderDict(dictCap)
+	if err != nil {
+		t.Fatalf("newDecoderDict error %s", err)
+	}
+	state.Reset()
+	r, err := newDecoder(&buf, state, decoderDict, -1)
+	if err != nil {
+		t.Fatalf("newDecoder error %s", err)
+	}
+	decoded, err := ioutil.ReadAll(r)
+	if err != nil {
+		t.Fatalf("ReadAll(lr) error %s", err)
+	}
+	t.Logf("decoded: %s", decoded)
+	if len(orig) != len(decoded) {
+		t.Fatalf("length decoded is %d; want %d", len(decoded),
+			len(orig))
+	}
+	if !bytes.Equal(orig, decoded) {
+		t.Fatalf("decoded file differs from original")
+	}
+}
+
+func TestEncoderCycle1(t *testing.T) {
+	cycle(t, len(testString))
+}
+
+func TestEncoderCycle2(t *testing.T) {
+	buf := new(bytes.Buffer)
+	const txtlen = 50000
+	io.CopyN(buf, randtxt.NewReader(rand.NewSource(42)), txtlen)
+	txt := buf.String()
+	buf.Reset()
+	const dictCap = MinDictCap
+	m, err := newHashTable(dictCap, 4)
+	if err != nil {
+		t.Fatal(err)
+	}
+	encoderDict, err := newEncoderDict(dictCap, dictCap+1024, m)
+	if err != nil {
+		t.Fatal(err)
+	}
+	props := Properties{3, 0, 2}
+	if err := props.verify(); err != nil {
+		t.Fatalf("properties error %s", err)
+	}
+	state := newState(props)
+	lbw := &LimitedByteWriter{BW: buf, N: 100}
+	w, err := newEncoder(lbw, state, encoderDict, 0)
+	if err != nil {
+		t.Fatalf("NewEncoder error %s", err)
+	}
+	_, err = io.WriteString(w, txt)
+	if err != nil && err != ErrLimit {
+		t.Fatalf("WriteString error %s", err)
+	}
+	if err = w.Close(); err != nil {
+		t.Fatalf("w.Close error %s", err)
+	}
+	n := w.Compressed()
+	txt = txt[:n]
+	decoderDict, err := newDecoderDict(dictCap)
+	if err != nil {
+		t.Fatalf("NewDecoderDict error %s", err)
+	}
+	state.Reset()
+	r, err := newDecoder(buf, state, decoderDict, n)
+	if err != nil {
+		t.Fatalf("NewDecoder error %s", err)
+	}
+	out := new(bytes.Buffer)
+	if _, err = io.Copy(out, r); err != nil {
+		t.Fatalf("decompress copy error %s", err)
+	}
+	got := out.String()
+	t.Logf("%s", got)
+	if len(got) != int(n) {
+		t.Fatalf("len(got) %d; want %d", len(got), n)
+	}
+	if got != txt {
+		t.Fatalf("got and txt differ")
+	}
+}

vendor/github.com/ulikunitz/xz/lzma/encoderdict.go

@@ -0,0 +1,149 @@
+// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package lzma
+
+import (
+	"errors"
+	"fmt"
+	"io"
+)
+
+// matcher is an interface that supports the identification of the next
+// operation.
+type matcher interface {
+	io.Writer
+	SetDict(d *encoderDict)
+	NextOp(rep [4]uint32) operation
+}
+
+// encoderDict provides the dictionary of the encoder. It includes an
+// addtional buffer atop of the actual dictionary.
+type encoderDict struct {
+	buf      buffer
+	m        matcher
+	head     int64
+	capacity int
+	// preallocated array
+	data [maxMatchLen]byte
+}
+
+// newEncoderDict creates the encoder dictionary. The argument bufSize
+// defines the size of the additional buffer.
+func newEncoderDict(dictCap, bufSize int, m matcher) (d *encoderDict, err error) {
+	if !(1 <= dictCap && int64(dictCap) <= MaxDictCap) {
+		return nil, errors.New(
+			"lzma: dictionary capacity out of range")
+	}
+	if bufSize < 1 {
+		return nil, errors.New(
+			"lzma: buffer size must be larger than zero")
+	}
+	d = &encoderDict{
+		buf:      *newBuffer(dictCap + bufSize),
+		capacity: dictCap,
+		m:        m,
+	}
+	m.SetDict(d)
+	return d, nil
+}
+
+// Discard discards n bytes. Note that n must not be larger than
+// MaxMatchLen.
+func (d *encoderDict) Discard(n int) {
+	p := d.data[:n]
+	k, _ := d.buf.Read(p)
+	if k < n {
+		panic(fmt.Errorf("lzma: can't discard %d bytes", n))
+	}
+	d.head += int64(n)
+	d.m.Write(p)
+}
+
+// Len returns the data available in the encoder dictionary.
+func (d *encoderDict) Len() int {
+	n := d.buf.Available()
+	if int64(n) > d.head {
+		return int(d.head)
+	}
+	return n
+}
+
+// DictLen returns the actual length of data in the dictionary.
+func (d *encoderDict) DictLen() int {
+	if d.head < int64(d.capacity) {
+		return int(d.head)
+	}
+	return d.capacity
+}
+
+// Available returns the number of bytes that can be written by a
+// following Write call.
+func (d *encoderDict) Available() int {
+	return d.buf.Available() - d.DictLen()
+}
+
+// Write writes data into the dictionary buffer. Note that the position
+// of the dictionary head will not be moved. If there is not enough
+// space in the buffer ErrNoSpace will be returned.
+func (d *encoderDict) Write(p []byte) (n int, err error) {
+	m := d.Available()
+	if len(p) > m {
+		p = p[:m]
+		err = ErrNoSpace
+	}
+	var e error
+	if n, e = d.buf.Write(p); e != nil {
+		err = e
+	}
+	return n, err
+}
+
+// Pos returns the position of the head.
+func (d *encoderDict) Pos() int64 { return d.head }
+
+// ByteAt returns the byte at the given distance.
+func (d *encoderDict) ByteAt(distance int) byte {
+	if !(0 < distance && distance <= d.Len()) {
+		return 0
+	}
+	i := d.buf.rear - distance
+	if i < 0 {
+		i += len(d.buf.data)
+	}
+	return d.buf.data[i]
+}
+
+// CopyN copies the last n bytes from the dictionary into the provided
+// writer. This is used for copying uncompressed data into an
+// uncompressed segment.
+func (d *encoderDict) CopyN(w io.Writer, n int) (written int, err error) {
+	if n <= 0 {
+		return 0, nil
+	}
+	m := d.Len()
+	if n > m {
+		n = m
+		err = ErrNoSpace
+	}
+	i := d.buf.rear - n
+	var e error
+	if i < 0 {
+		i += len(d.buf.data)
+		if written, e = w.Write(d.buf.data[i:]); e != nil {
+			return written, e
+		}
+		i = 0
+	}
+	var k int
+	k, e = w.Write(d.buf.data[i:d.buf.rear])
+	written += k
+	if e != nil {
+		err = e
+	}
+	return written, err
+}
+
+// Buffered returns the number of bytes in the buffer.
+func (d *encoderDict) Buffered() int { return d.buf.Buffered() }

vendor/github.com/ulikunitz/xz/lzma/hashtable.go

@@ -0,0 +1,309 @@
+// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package lzma
+
+import (
+	"errors"
+	"fmt"
+
+	"github.com/ulikunitz/xz/internal/hash"
+)
+
+/* For compression we need to find byte sequences that match the byte
+ * sequence at the dictionary head. A hash table is a simple method to
+ * provide this capability.
+ */
+
+// maxMatches limits the number of matches requested from the Matches
+// function. This controls the speed of the overall encoding.
+const maxMatches = 16
+
+// shortDists defines the number of short distances supported by the
+// implementation.
+const shortDists = 8
+
+// The minimum is somehow arbitrary but the maximum is limited by the
+// memory requirements of the hash table.
+const (
+	minTableExponent = 9
+	maxTableExponent = 20
+)
+
+// newRoller contains the function used to create an instance of the
+// hash.Roller.
+var newRoller = func(n int) hash.Roller { return hash.NewCyclicPoly(n) }
+
+// hashTable stores the hash table including the rolling hash method.
+//
+// We implement chained hashing into a circular buffer. Each entry in
+// the circular buffer stores the delta distance to the next position with a
+// word that has the same hash value.
+type hashTable struct {
+	dict *encoderDict
+	// actual hash table
+	t []int64
+	// circular list data with the offset to the next word
+	data  []uint32
+	front int
+	// mask for computing the index for the hash table
+	mask uint64
+	// hash offset; initial value is -int64(wordLen)
+	hoff int64
+	// length of the hashed word
+	wordLen int
+	// hash roller for computing the hash values for the Write
+	// method
+	wr hash.Roller
+	// hash roller for computing arbitrary hashes
+	hr hash.Roller
+	// preallocated slices
+	p         [maxMatches]int64
+	distances [maxMatches + shortDists]int
+}
+
+// hashTableExponent derives the hash table exponent from the dictionary
+// capacity.
+func hashTableExponent(n uint32) int {
+	e := 30 - nlz32(n)
+	switch {
+	case e < minTableExponent:
+		e = minTableExponent
+	case e > maxTableExponent:
+		e = maxTableExponent
+	}
+	return e
+}
+
+// newHashTable creates a new hash table for words of length wordLen
+func newHashTable(capacity int, wordLen int) (t *hashTable, err error) {
+	if !(0 < capacity) {
+		return nil, errors.New(
+			"newHashTable: capacity must not be negative")
+	}
+	exp := hashTableExponent(uint32(capacity))
+	if !(1 <= wordLen && wordLen <= 4) {
+		return nil, errors.New("newHashTable: " +
+			"argument wordLen out of range")
+	}
+	n := 1 << uint(exp)
+	if n <= 0 {
+		panic("newHashTable: exponent is too large")
+	}
+	t = &hashTable{
+		t:       make([]int64, n),
+		data:    make([]uint32, capacity),
+		mask:    (uint64(1) << uint(exp)) - 1,
+		hoff:    -int64(wordLen),
+		wordLen: wordLen,
+		wr:      newRoller(wordLen),
+		hr:      newRoller(wordLen),
+	}
+	return t, nil
+}
+
+func (t *hashTable) SetDict(d *encoderDict) { t.dict = d }
+
+// buffered returns the number of bytes that are currently hashed.
+func (t *hashTable) buffered() int {
+	n := t.hoff + 1
+	switch {
+	case n <= 0:
+		return 0
+	case n >= int64(len(t.data)):
+		return len(t.data)
+	}
+	return int(n)
+}
+
+// addIndex adds n to an index ensuring that is stays inside the
+// circular buffer for the hash chain.
+func (t *hashTable) addIndex(i, n int) int {
+	i += n - len(t.data)
+	if i < 0 {
+		i += len(t.data)
+	}
+	return i
+}
+
+// putDelta puts the delta instance at the current front of the circular
+// chain buffer.
+func (t *hashTable) putDelta(delta uint32) {
+	t.data[t.front] = delta
+	t.front = t.addIndex(t.front, 1)
+}
+
+// putEntry puts a new entry into the hash table. If there is already a
+// value stored it is moved into the circular chain buffer.
+func (t *hashTable) putEntry(h uint64, pos int64) {
+	if pos < 0 {
+		return
+	}
+	i := h & t.mask
+	old := t.t[i] - 1
+	t.t[i] = pos + 1
+	var delta int64
+	if old >= 0 {
+		delta = pos - old
+		if delta > 1<<32-1 || delta > int64(t.buffered()) {
+			delta = 0
+		}
+	}
+	t.putDelta(uint32(delta))
+}
+
+// WriteByte converts a single byte into a hash and puts them into the hash
+// table.
+func (t *hashTable) WriteByte(b byte) error {
+	h := t.wr.RollByte(b)
+	t.hoff++
+	t.putEntry(h, t.hoff)
+	return nil
+}
+
+// Write converts the bytes provided into hash tables and stores the
+// abbreviated offsets into the hash table. The method will never return an
+// error.
+func (t *hashTable) Write(p []byte) (n int, err error) {
+	for _, b := range p {
+		// WriteByte doesn't generate an error.
+		t.WriteByte(b)
+	}
+	return len(p), nil
+}
+
+// getMatches the matches for a specific hash. The functions returns the
+// number of positions found.
+//
+// TODO: Make a getDistances because that we are actually interested in.
+func (t *hashTable) getMatches(h uint64, positions []int64) (n int) {
+	if t.hoff < 0 || len(positions) == 0 {
+		return 0
+	}
+	buffered := t.buffered()
+	tailPos := t.hoff + 1 - int64(buffered)
+	rear := t.front - buffered
+	if rear >= 0 {
+		rear -= len(t.data)
+	}
+	// get the slot for the hash
+	pos := t.t[h&t.mask] - 1
+	delta := pos - tailPos
+	for {
+		if delta < 0 {
+			return n
+		}
+		positions[n] = tailPos + delta
+		n++
+		if n >= len(positions) {
+			return n
+		}
+		i := rear + int(delta)
+		if i < 0 {
+			i += len(t.data)
+		}
+		u := t.data[i]
+		if u == 0 {
+			return n
+		}
+		delta -= int64(u)
+	}
+}
+
+// hash computes the rolling hash for the word stored in p. For correct
+// results its length must be equal to t.wordLen.
+func (t *hashTable) hash(p []byte) uint64 {
+	var h uint64
+	for _, b := range p {
+		h = t.hr.RollByte(b)
+	}
+	return h
+}
+
+// Matches fills the positions slice with potential matches. The
+// functions returns the number of positions filled into positions. The
+// byte slice p must have word length of the hash table.
+func (t *hashTable) Matches(p []byte, positions []int64) int {
+	if len(p) != t.wordLen {
+		panic(fmt.Errorf(
+			"byte slice must have length %d", t.wordLen))
+	}
+	h := t.hash(p)
+	return t.getMatches(h, positions)
+}
+
+// NextOp identifies the next operation using the hash table.
+//
+// TODO: Use all repetitions to find matches.
+func (t *hashTable) NextOp(rep [4]uint32) operation {
+	// get positions
+	data := t.dict.data[:maxMatchLen]
+	n, _ := t.dict.buf.Peek(data)
+	data = data[:n]
+	var p []int64
+	if n < t.wordLen {
+		p = t.p[:0]
+	} else {
+		p = t.p[:maxMatches]
+		n = t.Matches(data[:t.wordLen], p)
+		p = p[:n]
+	}
+
+	// convert positions in potential distances
+	head := t.dict.head
+	dists := append(t.distances[:0], 1, 2, 3, 4, 5, 6, 7, 8)
+	for _, pos := range p {
+		dis := int(head - pos)
+		if dis > shortDists {
+			dists = append(dists, dis)
+		}
+	}
+
+	// check distances
+	var m match
+	dictLen := t.dict.DictLen()
+	for _, dist := range dists {
+		if dist > dictLen {
+			continue
+		}
+
+		// Here comes a trick. We are only interested in matches
+		// that are longer than the matches we have been found
+		// before. So before we test the whole byte sequence at
+		// the given distance, we test the first byte that would
+		// make the match longer. If it doesn't match the byte
+		// to match, we don't to care any longer.
+		i := t.dict.buf.rear - dist + m.n
+		if i < 0 {
+			i += len(t.dict.buf.data)
+		}
+		if t.dict.buf.data[i] != data[m.n] {
+			// We can't get a longer match. Jump to the next
+			// distance.
+			continue
+		}
+
+		n := t.dict.buf.matchLen(dist, data)
+		switch n {
+		case 0:
+			continue
+		case 1:
+			if uint32(dist-minDistance) != rep[0] {
+				continue
+			}
+		}
+		if n > m.n {
+			m = match{int64(dist), n}
+			if n == len(data) {
+				// No better match will be found.
+				break
+			}
+		}
+	}
+
+	if m.n == 0 {
+		return lit{data[0]}
+	}
+	return m
+}

vendor/github.com/ulikunitz/xz/lzma/hashtable_test.go

@@ -0,0 +1,47 @@
+// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package lzma
+
+import (
+	"fmt"
+	"testing"
+)
+
+func TestHashTable(t *testing.T) {
+	ht, err := newHashTable(32, 2)
+	if err != nil {
+		t.Fatalf("newHashTable: error %s", err)
+	}
+	//    01234567890123456
+	s := "abcabcdefghijklmn"
+	n, err := ht.Write([]byte(s))
+	if err != nil {
+		t.Fatalf("ht.Write: error %s", err)
+	}
+	if n != len(s) {
+		t.Fatalf("ht.Write returned %d; want %d", n, len(s))
+	}
+	tests := []struct {
+		s string
+		w string
+	}{
+		{"ab", "[3 0]"},
+		{"bc", "[4 1]"},
+		{"ca", "[2]"},
+		{"xx", "[]"},
+		{"gh", "[9]"},
+		{"mn", "[15]"},
+	}
+	distances := make([]int64, 20)
+	for _, c := range tests {
+		distances := distances[:20]
+		k := ht.Matches([]byte(c.s), distances)
+		distances = distances[:k]
+		o := fmt.Sprintf("%v", distances)
+		if o != c.w {
+			t.Errorf("%s: offsets %s; want %s", c.s, o, c.w)
+		}
+	}
+}

vendor/github.com/ulikunitz/xz/lzma/header.go

@@ -0,0 +1,167 @@
+// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package lzma
+
+import (
+	"errors"
+	"fmt"
+)
+
+// uint32LE reads an uint32 integer from a byte slice
+func uint32LE(b []byte) uint32 {
+	x := uint32(b[3]) << 24
+	x |= uint32(b[2]) << 16
+	x |= uint32(b[1]) << 8
+	x |= uint32(b[0])
+	return x
+}
+
+// uint64LE converts the uint64 value stored as little endian to an uint64
+// value.
+func uint64LE(b []byte) uint64 {
+	x := uint64(b[7]) << 56
+	x |= uint64(b[6]) << 48
+	x |= uint64(b[5]) << 40
+	x |= uint64(b[4]) << 32
+	x |= uint64(b[3]) << 24
+	x |= uint64(b[2]) << 16
+	x |= uint64(b[1]) << 8
+	x |= uint64(b[0])
+	return x
+}
+
+// putUint32LE puts an uint32 integer into a byte slice that must have at least
+// a length of 4 bytes.
+func putUint32LE(b []byte, x uint32) {
+	b[0] = byte(x)
+	b[1] = byte(x >> 8)
+	b[2] = byte(x >> 16)
+	b[3] = byte(x >> 24)
+}
+
+// putUint64LE puts the uint64 value into the byte slice as little endian
+// value. The byte slice b must have at least place for 8 bytes.
+func putUint64LE(b []byte, x uint64) {
+	b[0] = byte(x)
+	b[1] = byte(x >> 8)
+	b[2] = byte(x >> 16)
+	b[3] = byte(x >> 24)
+	b[4] = byte(x >> 32)
+	b[5] = byte(x >> 40)
+	b[6] = byte(x >> 48)
+	b[7] = byte(x >> 56)
+}
+
+// noHeaderSize defines the value of the length field in the LZMA header.
+const noHeaderSize uint64 = 1<<64 - 1
+
+// HeaderLen provides the length of the LZMA file header.
+const HeaderLen = 13
+
+// header represents the header of an LZMA file.
+type header struct {
+	properties Properties
+	dictCap    int
+	// uncompressed size; negative value if no size is given
+	size int64
+}
+
+// marshalBinary marshals the header.
+func (h *header) marshalBinary() (data []byte, err error) {
+	if err = h.properties.verify(); err != nil {
+		return nil, err
+	}
+	if !(0 <= h.dictCap && int64(h.dictCap) <= MaxDictCap) {
+		return nil, fmt.Errorf("lzma: DictCap %d out of range",
+			h.dictCap)
+	}
+
+	data = make([]byte, 13)
+
+	// property byte
+	data[0] = h.properties.Code()
+
+	// dictionary capacity
+	putUint32LE(data[1:5], uint32(h.dictCap))
+
+	// uncompressed size
+	var s uint64
+	if h.size > 0 {
+		s = uint64(h.size)
+	} else {
+		s = noHeaderSize
+	}
+	putUint64LE(data[5:], s)
+
+	return data, nil
+}
+
+// unmarshalBinary unmarshals the header.
+func (h *header) unmarshalBinary(data []byte) error {
+	if len(data) != HeaderLen {
+		return errors.New("lzma.unmarshalBinary: data has wrong length")
+	}
+
+	// properties
+	var err error
+	if h.properties, err = PropertiesForCode(data[0]); err != nil {
+		return err
+	}
+
+	// dictionary capacity
+	h.dictCap = int(uint32LE(data[1:]))
+	if h.dictCap < 0 {
+		return errors.New(
+			"LZMA header: dictionary capacity exceeds maximum " +
+				"integer")
+	}
+
+	// uncompressed size
+	s := uint64LE(data[5:])
+	if s == noHeaderSize {
+		h.size = -1
+	} else {
+		h.size = int64(s)
+		if h.size < 0 {
+			return errors.New(
+				"LZMA header: uncompressed size " +
+					"out of int64 range")
+		}
+	}
+
+	return nil
+}
+
+// validDictCap checks whether the dictionary capacity is correct. This
+// is used to weed out wrong file headers.
+func validDictCap(dictcap int) bool {
+	if int64(dictcap) == MaxDictCap {
+		return true
+	}
+	for n := uint(10); n < 32; n++ {
+		if dictcap == 1<<n {
+			return true
+		}
+		if dictcap == 1<<n+1<<(n-1) {
+			return true
+		}
+	}
+	return false
+}
+
+// ValidHeader checks for a valid LZMA file header. It allows only
+// dictionary sizes of 2^n or 2^n+2^(n-1) with n >= 10 or 2^32-1. If
+// there is an explicit size it must not exceed 256 GiB. The length of
+// the data argument must be HeaderLen.
+func ValidHeader(data []byte) bool {
+	var h header
+	if err := h.unmarshalBinary(data); err != nil {
+		return false
+	}
+	if !validDictCap(h.dictCap) {
+		return false
+	}
+	return h.size < 0 || h.size <= 1<<38
+}

vendor/github.com/ulikunitz/xz/lzma/header2.go

@@ -0,0 +1,398 @@
+// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package lzma
+
+import (
+	"errors"
+	"fmt"
+	"io"
+)
+
+const (
+	// maximum size of compressed data in a chunk
+	maxCompressed = 1 << 16
+	// maximum size of uncompressed data in a chunk
+	maxUncompressed = 1 << 21
+)
+
+// chunkType represents the type of an LZMA2 chunk. Note that this
+// value is an internal representation and no actual encoding of a LZMA2
+// chunk header.
+type chunkType byte
+
+// Possible values for the chunk type.
+const (
+	// end of stream
+	cEOS chunkType = iota
+	// uncompressed; reset dictionary
+	cUD
+	// uncompressed; no reset of dictionary
+	cU
+	// LZMA compressed; no reset
+	cL
+	// LZMA compressed; reset state
+	cLR
+	// LZMA compressed; reset state; new property value
+	cLRN
+	// LZMA compressed; reset state; new property value; reset dictionary
+	cLRND
+)
+
+// chunkTypeStrings provide a string representation for the chunk types.
+var chunkTypeStrings = [...]string{
+	cEOS:  "EOS",
+	cU:    "U",
+	cUD:   "UD",
+	cL:    "L",
+	cLR:   "LR",
+	cLRN:  "LRN",
+	cLRND: "LRND",
+}
+
+// String returns a string representation of the chunk type.
+func (c chunkType) String() string {
+	if !(cEOS <= c && c <= cLRND) {
+		return "unknown"
+	}
+	return chunkTypeStrings[c]
+}
+
+// Actual encodings for the chunk types in the value. Note that the high
+// uncompressed size bits are stored in the header byte additionally.
+const (
+	hEOS  = 0
+	hUD   = 1
+	hU    = 2
+	hL    = 1 << 7
+	hLR   = 1<<7 | 1<<5
+	hLRN  = 1<<7 | 1<<6
+	hLRND = 1<<7 | 1<<6 | 1<<5
+)
+
+// errHeaderByte indicates an unsupported value for the chunk header
+// byte. These bytes starts the variable-length chunk header.
+var errHeaderByte = errors.New("lzma: unsupported chunk header byte")
+
+// headerChunkType converts the header byte into a chunk type. It
+// ignores the uncompressed size bits in the chunk header byte.
+func headerChunkType(h byte) (c chunkType, err error) {
+	if h&hL == 0 {
+		// no compression
+		switch h {
+		case hEOS:
+			c = cEOS
+		case hUD:
+			c = cUD
+		case hU:
+			c = cU
+		default:
+			return 0, errHeaderByte
+		}
+		return
+	}
+	switch h & hLRND {
+	case hL:
+		c = cL
+	case hLR:
+		c = cLR
+	case hLRN:
+		c = cLRN
+	case hLRND:
+		c = cLRND
+	default:
+		return 0, errHeaderByte
+	}
+	return
+}
+
+// uncompressedHeaderLen provides the length of an uncompressed header
+const uncompressedHeaderLen = 3
+
+// headerLen returns the length of the LZMA2 header for a given chunk
+// type.
+func headerLen(c chunkType) int {
+	switch c {
+	case cEOS:
+		return 1
+	case cU, cUD:
+		return uncompressedHeaderLen
+	case cL, cLR:
+		return 5
+	case cLRN, cLRND:
+		return 6
+	}
+	panic(fmt.Errorf("unsupported chunk type %d", c))
+}
+
+// chunkHeader represents the contents of a chunk header.
+type chunkHeader struct {
+	ctype        chunkType
+	uncompressed uint32
+	compressed   uint16
+	props        Properties
+}
+
+// String returns a string representation of the chunk header.
+func (h *chunkHeader) String() string {
+	return fmt.Sprintf("%s %d %d %s", h.ctype, h.uncompressed,
+		h.compressed, &h.props)
+}
+
+// UnmarshalBinary reads the content of the chunk header from the data
+// slice. The slice must have the correct length.
+func (h *chunkHeader) UnmarshalBinary(data []byte) error {
+	if len(data) == 0 {
+		return errors.New("no data")
+	}
+	c, err := headerChunkType(data[0])
+	if err != nil {
+		return err
+	}
+
+	n := headerLen(c)
+	if len(data) < n {
+		return errors.New("incomplete data")
+	}
+	if len(data) > n {
+		return errors.New("invalid data length")
+	}
+
+	*h = chunkHeader{ctype: c}
+	if c == cEOS {
+		return nil
+	}
+
+	h.uncompressed = uint32(uint16BE(data[1:3]))
+	if c <= cU {
+		return nil
+	}
+	h.uncompressed |= uint32(data[0]&^hLRND) << 16
+
+	h.compressed = uint16BE(data[3:5])
+	if c <= cLR {
+		return nil
+	}
+
+	h.props, err = PropertiesForCode(data[5])
+	return err
+}
+
+// MarshalBinary encodes the chunk header value. The function checks
+// whether the content of the chunk header is correct.
+func (h *chunkHeader) MarshalBinary() (data []byte, err error) {
+	if h.ctype > cLRND {
+		return nil, errors.New("invalid chunk type")
+	}
+	if err = h.props.verify(); err != nil {
+		return nil, err
+	}
+
+	data = make([]byte, headerLen(h.ctype))
+
+	switch h.ctype {
+	case cEOS:
+		return data, nil
+	case cUD:
+		data[0] = hUD
+	case cU:
+		data[0] = hU
+	case cL:
+		data[0] = hL
+	case cLR:
+		data[0] = hLR
+	case cLRN:
+		data[0] = hLRN
+	case cLRND:
+		data[0] = hLRND
+	}
+
+	putUint16BE(data[1:3], uint16(h.uncompressed))
+	if h.ctype <= cU {
+		return data, nil
+	}
+	data[0] |= byte(h.uncompressed>>16) &^ hLRND
+
+	putUint16BE(data[3:5], h.compressed)
+	if h.ctype <= cLR {
+		return data, nil
+	}
+
+	data[5] = h.props.Code()
+	return data, nil
+}
+
+// readChunkHeader reads the chunk header from the IO reader.
+func readChunkHeader(r io.Reader) (h *chunkHeader, err error) {
+	p := make([]byte, 1, 6)
+	if _, err = io.ReadFull(r, p); err != nil {
+		return
+	}
+	c, err := headerChunkType(p[0])
+	if err != nil {
+		return
+	}
+	p = p[:headerLen(c)]
+	if _, err = io.ReadFull(r, p[1:]); err != nil {
+		return
+	}
+	h = new(chunkHeader)
+	if err = h.UnmarshalBinary(p); err != nil {
+		return nil, err
+	}
+	return h, nil
+}
+
+// uint16BE converts a big-endian uint16 representation to an uint16
+// value.
+func uint16BE(p []byte) uint16 {
+	return uint16(p[0])<<8 | uint16(p[1])
+}
+
+// putUint16BE puts the big-endian uint16 presentation into the given
+// slice.
+func putUint16BE(p []byte, x uint16) {
+	p[0] = byte(x >> 8)
+	p[1] = byte(x)
+}
+
+// chunkState is used to manage the state of the chunks
+type chunkState byte
+
+// start and stop define the initial and terminating state of the chunk
+// state
+const (
+	start chunkState = 'S'
+	stop             = 'T'
+)
+
+// errors for the chunk state handling
+var (
+	errChunkType = errors.New("lzma: unexpected chunk type")
+	errState     = errors.New("lzma: wrong chunk state")
+)
+
+// next transitions state based on chunk type input
+func (c *chunkState) next(ctype chunkType) error {
+	switch *c {
+	// start state
+	case 'S':
+		switch ctype {
+		case cEOS:
+			*c = 'T'
+		case cUD:
+			*c = 'R'
+		case cLRND:
+			*c = 'L'
+		default:
+			return errChunkType
+		}
+	// normal LZMA mode
+	case 'L':
+		switch ctype {
+		case cEOS:
+			*c = 'T'
+		case cUD:
+			*c = 'R'
+		case cU:
+			*c = 'U'
+		case cL, cLR, cLRN, cLRND:
+			break
+		default:
+			return errChunkType
+		}
+	// reset required
+	case 'R':
+		switch ctype {
+		case cEOS:
+			*c = 'T'
+		case cUD, cU:
+			break
+		case cLRN, cLRND:
+			*c = 'L'
+		default:
+			return errChunkType
+		}
+	// uncompressed
+	case 'U':
+		switch ctype {
+		case cEOS:
+			*c = 'T'
+		case cUD:
+			*c = 'R'
+		case cU:
+			break
+		case cL, cLR, cLRN, cLRND:
+			*c = 'L'
+		default:
+			return errChunkType
+		}
+	// terminal state
+	case 'T':
+		return errChunkType
+	default:
+		return errState
+	}
+	return nil
+}
+
+// defaultChunkType returns the default chunk type for each chunk state.
+func (c chunkState) defaultChunkType() chunkType {
+	switch c {
+	case 'S':
+		return cLRND
+	case 'L', 'U':
+		return cL
+	case 'R':
+		return cLRN
+	default:
+		// no error
+		return cEOS
+	}
+}
+
+// maxDictCap defines the maximum dictionary capacity supported by the
+// LZMA2 dictionary capacity encoding.
+const maxDictCap = 1<<32 - 1
+
+// maxDictCapCode defines the maximum dictionary capacity code.
+const maxDictCapCode = 40
+
+// The function decodes the dictionary capacity byte, but doesn't change
+// for the correct range of the given byte.
+func decodeDictCap(c byte) int64 {
+	return (2 | int64(c)&1) << (11 + (c>>1)&0x1f)
+}
+
+// DecodeDictCap decodes the encoded dictionary capacity. The function
+// returns an error if the code is out of range.
+func DecodeDictCap(c byte) (n int64, err error) {
+	if c >= maxDictCapCode {
+		if c == maxDictCapCode {
+			return maxDictCap, nil
+		}
+		return 0, errors.New("lzma: invalid dictionary size code")
+	}
+	return decodeDictCap(c), nil
+}
+
+// EncodeDictCap encodes a dictionary capacity. The function returns the
+// code for the capacity that is greater or equal n. If n exceeds the
+// maximum support dictionary capacity, the maximum value is returned.
+func EncodeDictCap(n int64) byte {
+	a, b := byte(0), byte(40)
+	for a < b {
+		c := a + (b-a)>>1
+		m := decodeDictCap(c)
+		if n <= m {
+			if n == m {
+				return c
+			}
+			b = c
+		} else {
+			a = c + 1
+		}
+	}
+	return a
+}

vendor/github.com/ulikunitz/xz/lzma/header2_test.go

@@ -0,0 +1,153 @@
+// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package lzma
+
+import (
+	"bytes"
+	"fmt"
+	"testing"
+)
+
+func TestChunkTypeString(t *testing.T) {
+	tests := [...]struct {
+		c chunkType
+		s string
+	}{
+		{cEOS, "EOS"},
+		{cUD, "UD"},
+		{cU, "U"},
+		{cL, "L"},
+		{cLR, "LR"},
+		{cLRN, "LRN"},
+		{cLRND, "LRND"},
+	}
+	for _, c := range tests {
+		s := fmt.Sprintf("%v", c.c)
+		if s != c.s {
+			t.Errorf("got %s; want %s", s, c.s)
+		}
+	}
+}
+
+func TestHeaderChunkType(t *testing.T) {
+	tests := []struct {
+		h byte
+		c chunkType
+	}{
+		{h: 0, c: cEOS},
+		{h: 1, c: cUD},
+		{h: 2, c: cU},
+		{h: 1<<7 | 0x1f, c: cL},
+		{h: 1<<7 | 1<<5 | 0x1f, c: cLR},
+		{h: 1<<7 | 1<<6 | 0x1f, c: cLRN},
+		{h: 1<<7 | 1<<6 | 1<<5 | 0x1f, c: cLRND},
+		{h: 1<<7 | 1<<6 | 1<<5, c: cLRND},
+	}
+	if _, err := headerChunkType(3); err == nil {
+		t.Fatalf("headerChunkType(%d) got %v; want %v",
+			3, err, errHeaderByte)
+	}
+	for _, tc := range tests {
+		c, err := headerChunkType(tc.h)
+		if err != nil {
+			t.Fatalf("headerChunkType error %s", err)
+		}
+		if c != tc.c {
+			t.Errorf("got %s; want %s", c, tc.c)
+		}
+	}
+}
+
+func TestHeaderLen(t *testing.T) {
+	tests := []struct {
+		c chunkType
+		n int
+	}{
+		{cEOS, 1}, {cU, 3}, {cUD, 3}, {cL, 5}, {cLR, 5}, {cLRN, 6},
+		{cLRND, 6},
+	}
+	for _, tc := range tests {
+		n := headerLen(tc.c)
+		if n != tc.n {
+			t.Errorf("header length for %s %d; want %d",
+				tc.c, n, tc.n)
+		}
+	}
+}
+
+func chunkHeaderSamples(t *testing.T) []chunkHeader {
+	props := Properties{LC: 3, LP: 0, PB: 2}
+	headers := make([]chunkHeader, 0, 12)
+	for c := cEOS; c <= cLRND; c++ {
+		var h chunkHeader
+		h.ctype = c
+		if c >= cUD {
+			h.uncompressed = 0x0304
+		}
+		if c >= cL {
+			h.compressed = 0x0201
+		}
+		if c >= cLRN {
+			h.props = props
+		}
+		headers = append(headers, h)
+	}
+	return headers
+}
+
+func TestChunkHeaderMarshalling(t *testing.T) {
+	for _, h := range chunkHeaderSamples(t) {
+		data, err := h.MarshalBinary()
+		if err != nil {
+			t.Fatalf("MarshalBinary for %v error %s", h, err)
+		}
+		var g chunkHeader
+		if err = g.UnmarshalBinary(data); err != nil {
+			t.Fatalf("UnmarshalBinary error %s", err)
+		}
+		if g != h {
+			t.Fatalf("got %v; want %v", g, h)
+		}
+	}
+}
+
+func TestReadChunkHeader(t *testing.T) {
+	for _, h := range chunkHeaderSamples(t) {
+		data, err := h.MarshalBinary()
+		if err != nil {
+			t.Fatalf("MarshalBinary for %v error %s", h, err)
+		}
+		r := bytes.NewReader(data)
+		g, err := readChunkHeader(r)
+		if err != nil {
+			t.Fatalf("readChunkHeader for %v error %s", h, err)
+		}
+		if *g != h {
+			t.Fatalf("got %v; want %v", g, h)
+		}
+	}
+}
+
+func TestReadEOS(t *testing.T) {
+	var b [1]byte
+	r := bytes.NewReader(b[:])
+	h, err := readChunkHeader(r)
+	if err != nil {
+		t.Fatalf("readChunkHeader error %s", err)
+	}
+	if h.ctype != cEOS {
+		t.Errorf("ctype got %s; want %s", h.ctype, cEOS)
+	}
+	if h.compressed != 0 {
+		t.Errorf("compressed got %d; want %d", h.compressed, 0)
+	}
+	if h.uncompressed != 0 {
+		t.Errorf("uncompressed got %d; want %d", h.uncompressed, 0)
+	}
+	wantProps := Properties{}
+	if h.props != wantProps {
+		t.Errorf("props got %v; want %v", h.props, wantProps)
+	}
+}

vendor/github.com/ulikunitz/xz/lzma/header_test.go

@@ -0,0 +1,52 @@
+// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package lzma
+
+import "testing"
+
+func TestHeaderMarshalling(t *testing.T) {
+	tests := []header{
+		{properties: Properties{3, 0, 2}, dictCap: 8 * 1024 * 1024,
+			size: -1},
+		{properties: Properties{4, 3, 3}, dictCap: 4096,
+			size: 10},
+	}
+	for _, h := range tests {
+		data, err := h.marshalBinary()
+		if err != nil {
+			t.Fatalf("marshalBinary error %s", err)
+		}
+		var g header
+		if err = g.unmarshalBinary(data); err != nil {
+			t.Fatalf("unmarshalBinary error %s", err)
+		}
+		if h != g {
+			t.Errorf("got header %#v; want %#v", g, h)
+		}
+	}
+}
+
+func TestValidHeader(t *testing.T) {
+	tests := []header{
+		{properties: Properties{3, 0, 2}, dictCap: 8 * 1024 * 1024,
+			size: -1},
+		{properties: Properties{4, 3, 3}, dictCap: 4096,
+			size: 10},
+	}
+	for _, h := range tests {
+		data, err := h.marshalBinary()
+		if err != nil {
+			t.Fatalf("marshalBinary error %s", err)
+		}
+		if !ValidHeader(data) {
+			t.Errorf("ValidHeader returns false for header %v;"+
+				" want true", h)
+		}
+	}
+	const a = "1234567890123"
+	if ValidHeader([]byte(a)) {
+		t.Errorf("ValidHeader returns true for %s; want false", a)
+	}
+}

vendor/github.com/ulikunitz/xz/lzma/lengthcodec.go

@@ -0,0 +1,129 @@
+// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package lzma
+
+import "errors"
+
+// maxPosBits defines the number of bits of the position value that are used to
+// to compute the posState value. The value is used to select the tree codec
+// for length encoding and decoding.
+const maxPosBits = 4
+
+// minMatchLen and maxMatchLen give the minimum and maximum values for
+// encoding and decoding length values. minMatchLen is also used as base
+// for the encoded length values.
+const (
+	minMatchLen = 2
+	maxMatchLen = minMatchLen + 16 + 256 - 1
+)
+
+// lengthCodec support the encoding of the length value.
+type lengthCodec struct {
+	choice [2]prob
+	low    [1 << maxPosBits]treeCodec
+	mid    [1 << maxPosBits]treeCodec
+	high   treeCodec
+}
+
+// deepcopy initializes the lc value as deep copy of the source value.
+func (lc *lengthCodec) deepcopy(src *lengthCodec) {
+	if lc == src {
+		return
+	}
+	lc.choice = src.choice
+	for i := range lc.low {
+		lc.low[i].deepcopy(&src.low[i])
+	}
+	for i := range lc.mid {
+		lc.mid[i].deepcopy(&src.mid[i])
+	}
+	lc.high.deepcopy(&src.high)
+}
+
+// init initializes a new length codec.
+func (lc *lengthCodec) init() {
+	for i := range lc.choice {
+		lc.choice[i] = probInit
+	}
+	for i := range lc.low {
+		lc.low[i] = makeTreeCodec(3)
+	}
+	for i := range lc.mid {
+		lc.mid[i] = makeTreeCodec(3)
+	}
+	lc.high = makeTreeCodec(8)
+}
+
+// lBits gives the number of bits used for the encoding of the l value
+// provided to the range encoder.
+func lBits(l uint32) int {
+	switch {
+	case l < 8:
+		return 4
+	case l < 16:
+		return 5
+	default:
+		return 10
+	}
+}
+
+// Encode encodes the length offset. The length offset l can be compute by
+// subtracting minMatchLen (2) from the actual length.
+//
+//   l = length - minMatchLen
+//
+func (lc *lengthCodec) Encode(e *rangeEncoder, l uint32, posState uint32,
+) (err error) {
+	if l > maxMatchLen-minMatchLen {
+		return errors.New("lengthCodec.Encode: l out of range")
+	}
+	if l < 8 {
+		if err = lc.choice[0].Encode(e, 0); err != nil {
+			return
+		}
+		return lc.low[posState].Encode(e, l)
+	}
+	if err = lc.choice[0].Encode(e, 1); err != nil {
+		return
+	}
+	if l < 16 {
+		if err = lc.choice[1].Encode(e, 0); err != nil {
+			return
+		}
+		return lc.mid[posState].Encode(e, l-8)
+	}
+	if err = lc.choice[1].Encode(e, 1); err != nil {
+		return
+	}
+	if err = lc.high.Encode(e, l-16); err != nil {
+		return
+	}
+	return nil
+}
+
+// Decode reads the length offset. Add minMatchLen to compute the actual length
+// to the length offset l.
+func (lc *lengthCodec) Decode(d *rangeDecoder, posState uint32,
+) (l uint32, err error) {
+	var b uint32
+	if b, err = lc.choice[0].Decode(d); err != nil {
+		return
+	}
+	if b == 0 {
+		l, err = lc.low[posState].Decode(d)
+		return
+	}
+	if b, err = lc.choice[1].Decode(d); err != nil {
+		return
+	}
+	if b == 0 {
+		l, err = lc.mid[posState].Decode(d)
+		l += 8
+		return
+	}
+	l, err = lc.high.Decode(d)
+	l += 16
+	return
+}

vendor/github.com/ulikunitz/xz/lzma/literalcodec.go

@@ -0,0 +1,132 @@
+// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package lzma
+
+// literalCodec supports the encoding of literal. It provides 768 probability
+// values per literal state. The upper 512 probabilities are used with the
+// context of a match bit.
+type literalCodec struct {
+	probs []prob
+}
+
+// deepcopy initializes literal codec c as a deep copy of the source.
+func (c *literalCodec) deepcopy(src *literalCodec) {
+	if c == src {
+		return
+	}
+	c.probs = make([]prob, len(src.probs))
+	copy(c.probs, src.probs)
+}
+
+// init initializes the literal codec.
+func (c *literalCodec) init(lc, lp int) {
+	switch {
+	case !(minLC <= lc && lc <= maxLC):
+		panic("lc out of range")
+	case !(minLP <= lp && lp <= maxLP):
+		panic("lp out of range")
+	}
+	c.probs = make([]prob, 0x300<<uint(lc+lp))
+	for i := range c.probs {
+		c.probs[i] = probInit
+	}
+}
+
+// Encode encodes the byte s using a range encoder as well as the current LZMA
+// encoder state, a match byte and the literal state.
+func (c *literalCodec) Encode(e *rangeEncoder, s byte,
+	state uint32, match byte, litState uint32,
+) (err error) {
+	k := litState * 0x300
+	probs := c.probs[k : k+0x300]
+	symbol := uint32(1)
+	r := uint32(s)
+	if state >= 7 {
+		m := uint32(match)
+		for {
+			matchBit := (m >> 7) & 1
+			m <<= 1
+			bit := (r >> 7) & 1
+			r <<= 1
+			i := ((1 + matchBit) << 8) | symbol
+			if err = probs[i].Encode(e, bit); err != nil {
+				return
+			}
+			symbol = (symbol << 1) | bit
+			if matchBit != bit {
+				break
+			}
+			if symbol >= 0x100 {
+				break
+			}
+		}
+	}
+	for symbol < 0x100 {
+		bit := (r >> 7) & 1
+		r <<= 1
+		if err = probs[symbol].Encode(e, bit); err != nil {
+			return
+		}
+		symbol = (symbol << 1) | bit
+	}
+	return nil
+}
+
+// Decode decodes a literal byte using the range decoder as well as the LZMA
+// state, a match byte, and the literal state.
+func (c *literalCodec) Decode(d *rangeDecoder,
+	state uint32, match byte, litState uint32,
+) (s byte, err error) {
+	k := litState * 0x300
+	probs := c.probs[k : k+0x300]
+	symbol := uint32(1)
+	if state >= 7 {
+		m := uint32(match)
+		for {
+			matchBit := (m >> 7) & 1
+			m <<= 1
+			i := ((1 + matchBit) << 8) | symbol
+			bit, err := d.DecodeBit(&probs[i])
+			if err != nil {
+				return 0, err
+			}
+			symbol = (symbol << 1) | bit
+			if matchBit != bit {
+				break
+			}
+			if symbol >= 0x100 {
+				break
+			}
+		}
+	}
+	for symbol < 0x100 {
+		bit, err := d.DecodeBit(&probs[symbol])
+		if err != nil {
+			return 0, err
+		}
+		symbol = (symbol << 1) | bit
+	}
+	s = byte(symbol - 0x100)
+	return s, nil
+}
+
+// minLC and maxLC define the range for LC values.
+const (
+	minLC = 0
+	maxLC = 8
+)
+
+// minLC and maxLC define the range for LP values.
+const (
+	minLP = 0
+	maxLP = 4
+)
+
+// minState and maxState define a range for the state values stored in
+// the State values.
+const (
+	minState = 0
+	maxState = 11
+)

vendor/github.com/ulikunitz/xz/lzma/matchalgorithm.go

@@ -0,0 +1,52 @@
+// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package lzma
+
+import "errors"
+
+// MatchAlgorithm identifies an algorithm to find matches in the
+// dictionary.
+type MatchAlgorithm byte
+
+// Supported matcher algorithms.
+const (
+	HashTable4 MatchAlgorithm = iota
+	BinaryTree
+)
+
+// maStrings are used by the String method.
+var maStrings = map[MatchAlgorithm]string{
+	HashTable4: "HashTable4",
+	BinaryTree: "BinaryTree",
+}
+
+// String returns a string representation of the Matcher.
+func (a MatchAlgorithm) String() string {
+	if s, ok := maStrings[a]; ok {
+		return s
+	}
+	return "unknown"
+}
+
+var errUnsupportedMatchAlgorithm = errors.New(
+	"lzma: unsupported match algorithm value")
+
+// verify checks whether the matcher value is supported.
+func (a MatchAlgorithm) verify() error {
+	if _, ok := maStrings[a]; !ok {
+		return errUnsupportedMatchAlgorithm
+	}
+	return nil
+}
+
+func (a MatchAlgorithm) new(dictCap int) (m matcher, err error) {
+	switch a {
+	case HashTable4:
+		return newHashTable(dictCap, 4)
+	case BinaryTree:
+		return newBinTree(dictCap)
+	}
+	return nil, errUnsupportedMatchAlgorithm
+}

vendor/github.com/ulikunitz/xz/lzma/operation.go

@@ -0,0 +1,80 @@
+// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package lzma
+
+import (
+	"errors"
+	"fmt"
+	"unicode"
+)
+
+// operation represents an operation on the dictionary during encoding or
+// decoding.
+type operation interface {
+	Len() int
+}
+
+// rep represents a repetition at the given distance and the given length
+type match struct {
+	// supports all possible distance values, including the eos marker
+	distance int64
+	// length
+	n int
+}
+
+// verify checks whether the match is valid. If that is not the case an
+// error is returned.
+func (m match) verify() error {
+	if !(minDistance <= m.distance && m.distance <= maxDistance) {
+		return errors.New("distance out of range")
+	}
+	if !(1 <= m.n && m.n <= maxMatchLen) {
+		return errors.New("length out of range")
+	}
+	return nil
+}
+
+// l return the l-value for the match, which is the difference of length
+// n and 2.
+func (m match) l() uint32 {
+	return uint32(m.n - minMatchLen)
+}
+
+// dist returns the dist value for the match, which is one less of the
+// distance stored in the match.
+func (m match) dist() uint32 {
+	return uint32(m.distance - minDistance)
+}
+
+// Len returns the number of bytes matched.
+func (m match) Len() int {
+	return m.n
+}
+
+// String returns a string representation for the repetition.
+func (m match) String() string {
+	return fmt.Sprintf("M{%d,%d}", m.distance, m.n)
+}
+
+// lit represents a single byte literal.
+type lit struct {
+	b byte
+}
+
+// Len returns 1 for the single byte literal.
+func (l lit) Len() int {
+	return 1
+}
+
+// String returns a string representation for the literal.
+func (l lit) String() string {
+	var c byte
+	if unicode.IsPrint(rune(l.b)) {
+		c = l.b
+	} else {
+		c = '.'
+	}
+	return fmt.Sprintf("L{%c/%02x}", c, l.b)
+}

vendor/github.com/ulikunitz/xz/lzma/prob.go

@@ -0,0 +1,53 @@
+// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package lzma
+
+// movebits defines the number of bits used for the updates of probability
+// values.
+const movebits = 5
+
+// probbits defines the number of bits of a probability value.
+const probbits = 11
+
+// probInit defines 0.5 as initial value for prob values.
+const probInit prob = 1 << (probbits - 1)
+
+// Type prob represents probabilities. The type can also be used to encode and
+// decode single bits.
+type prob uint16
+
+// Dec decreases the probability. The decrease is proportional to the
+// probability value.
+func (p *prob) dec() {
+	*p -= *p >> movebits
+}
+
+// Inc increases the probability. The Increase is proportional to the
+// difference of 1 and the probability value.
+func (p *prob) inc() {
+	*p += ((1 << probbits) - *p) >> movebits
+}
+
+// Computes the new bound for a given range using the probability value.
+func (p prob) bound(r uint32) uint32 {
+	return (r >> probbits) * uint32(p)
+}
+
+// Bits returns 1. One is the number of bits that can be encoded or decoded
+// with a single prob value.
+func (p prob) Bits() int {
+	return 1
+}
+
+// Encode encodes the least-significant bit of v. Note that the p value will be
+// changed.
+func (p *prob) Encode(e *rangeEncoder, v uint32) error {
+	return e.EncodeBit(v, p)
+}
+
+// Decode decodes a single bit. Note that the p value will change.
+func (p *prob) Decode(d *rangeDecoder) (v uint32, err error) {
+	return d.DecodeBit(p)
+}

vendor/github.com/ulikunitz/xz/lzma/properties.go

@@ -0,0 +1,69 @@
+// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package lzma
+
+import (
+	"errors"
+	"fmt"
+)
+
+// maximum and minimum values for the LZMA properties.
+const (
+	minPB = 0
+	maxPB = 4
+)
+
+// maxPropertyCode is the possible maximum of a properties code byte.
+const maxPropertyCode = (maxPB+1)*(maxLP+1)*(maxLC+1) - 1
+
+// Properties contains the parameters LC, LP and PB. The parameter LC
+// defines the number of literal context bits; parameter LP the number
+// of literal position bits and PB the number of position bits.
+type Properties struct {
+	LC int
+	LP int
+	PB int
+}
+
+// String returns the properties in a string representation.
+func (p *Properties) String() string {
+	return fmt.Sprintf("LC %d LP %d PB %d", p.LC, p.LP, p.PB)
+}
+
+// PropertiesForCode converts a properties code byte into a Properties value.
+func PropertiesForCode(code byte) (p Properties, err error) {
+	if code > maxPropertyCode {
+		return p, errors.New("lzma: invalid properties code")
+	}
+	p.LC = int(code % 9)
+	code /= 9
+	p.LP = int(code % 5)
+	code /= 5
+	p.PB = int(code % 5)
+	return p, err
+}
+
+// verify checks the properties for correctness.
+func (p *Properties) verify() error {
+	if p == nil {
+		return errors.New("lzma: properties are nil")
+	}
+	if !(minLC <= p.LC && p.LC <= maxLC) {
+		return errors.New("lzma: lc out of range")
+	}
+	if !(minLP <= p.LP && p.LP <= maxLP) {
+		return errors.New("lzma: lp out of range")
+	}
+	if !(minPB <= p.PB && p.PB <= maxPB) {
+		return errors.New("lzma: pb out of range")
+	}
+	return nil
+}
+
+// Code converts the properties to a byte. The function assumes that
+// the properties components are all in range.
+func (p Properties) Code() byte {
+	return byte((p.PB*5+p.LP)*9 + p.LC)
+}

vendor/github.com/ulikunitz/xz/lzma/rangecodec.go

@@ -0,0 +1,248 @@
+// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package lzma
+
+import (
+	"errors"
+	"io"
+)
+
+// rangeEncoder implements range encoding of single bits. The low value can
+// overflow therefore we need uint64. The cache value is used to handle
+// overflows.
+type rangeEncoder struct {
+	lbw      *LimitedByteWriter
+	nrange   uint32
+	low      uint64
+	cacheLen int64
+	cache    byte
+}
+
+// maxInt64 provides the  maximal value of the int64 type
+const maxInt64 = 1<<63 - 1
+
+// newRangeEncoder creates a new range encoder.
+func newRangeEncoder(bw io.ByteWriter) (re *rangeEncoder, err error) {
+	lbw, ok := bw.(*LimitedByteWriter)
+	if !ok {
+		lbw = &LimitedByteWriter{BW: bw, N: maxInt64}
+	}
+	return &rangeEncoder{
+		lbw:      lbw,
+		nrange:   0xffffffff,
+		cacheLen: 1}, nil
+}
+
+// Available returns the number of bytes that still can be written. The
+// method takes the bytes that will be currently written by Close into
+// account.
+func (e *rangeEncoder) Available() int64 {
+	return e.lbw.N - (e.cacheLen + 4)
+}
+
+// writeByte writes a single byte to the underlying writer. An error is
+// returned if the limit is reached. The written byte will be counted if
+// the underlying writer doesn't return an error.
+func (e *rangeEncoder) writeByte(c byte) error {
+	if e.Available() < 1 {
+		return ErrLimit
+	}
+	return e.lbw.WriteByte(c)
+}
+
+// DirectEncodeBit encodes the least-significant bit of b with probability 1/2.
+func (e *rangeEncoder) DirectEncodeBit(b uint32) error {
+	e.nrange >>= 1
+	e.low += uint64(e.nrange) & (0 - (uint64(b) & 1))
+
+	// normalize
+	const top = 1 << 24
+	if e.nrange >= top {
+		return nil
+	}
+	e.nrange <<= 8
+	return e.shiftLow()
+}
+
+// EncodeBit encodes the least significant bit of b. The p value will be
+// updated by the function depending on the bit encoded.
+func (e *rangeEncoder) EncodeBit(b uint32, p *prob) error {
+	bound := p.bound(e.nrange)
+	if b&1 == 0 {
+		e.nrange = bound
+		p.inc()
+	} else {
+		e.low += uint64(bound)
+		e.nrange -= bound
+		p.dec()
+	}
+
+	// normalize
+	const top = 1 << 24
+	if e.nrange >= top {
+		return nil
+	}
+	e.nrange <<= 8
+	return e.shiftLow()
+}
+
+// Close writes a complete copy of the low value.
+func (e *rangeEncoder) Close() error {
+	for i := 0; i < 5; i++ {
+		if err := e.shiftLow(); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// shiftLow shifts the low value for 8 bit. The shifted byte is written into
+// the byte writer. The cache value is used to handle overflows.
+func (e *rangeEncoder) shiftLow() error {
+	if uint32(e.low) < 0xff000000 || (e.low>>32) != 0 {
+		tmp := e.cache
+		for {
+			err := e.writeByte(tmp + byte(e.low>>32))
+			if err != nil {
+				return err
+			}
+			tmp = 0xff
+			e.cacheLen--
+			if e.cacheLen <= 0 {
+				if e.cacheLen < 0 {
+					panic("negative cacheLen")
+				}
+				break
+			}
+		}
+		e.cache = byte(uint32(e.low) >> 24)
+	}
+	e.cacheLen++
+	e.low = uint64(uint32(e.low) << 8)
+	return nil
+}
+
+// rangeDecoder decodes single bits of the range encoding stream.
+type rangeDecoder struct {
+	br     io.ByteReader
+	nrange uint32
+	code   uint32
+}
+
+// init initializes the range decoder, by reading from the byte reader.
+func (d *rangeDecoder) init() error {
+	d.nrange = 0xffffffff
+	d.code = 0
+
+	b, err := d.br.ReadByte()
+	if err != nil {
+		return err
+	}
+	if b != 0 {
+		return errors.New("newRangeDecoder: first byte not zero")
+	}
+
+	for i := 0; i < 4; i++ {
+		if err = d.updateCode(); err != nil {
+			return err
+		}
+	}
+
+	if d.code >= d.nrange {
+		return errors.New("newRangeDecoder: d.code >= d.nrange")
+	}
+
+	return nil
+}
+
+// newRangeDecoder initializes a range decoder. It reads five bytes from the
+// reader and therefore may return an error.
+func newRangeDecoder(br io.ByteReader) (d *rangeDecoder, err error) {
+	d = &rangeDecoder{br: br, nrange: 0xffffffff}
+
+	b, err := d.br.ReadByte()
+	if err != nil {
+		return nil, err
+	}
+	if b != 0 {
+		return nil, errors.New("newRangeDecoder: first byte not zero")
+	}
+
+	for i := 0; i < 4; i++ {
+		if err = d.updateCode(); err != nil {
+			return nil, err
+		}
+	}
+
+	if d.code >= d.nrange {
+		return nil, errors.New("newRangeDecoder: d.code >= d.nrange")
+	}
+
+	return d, nil
+}
+
+// possiblyAtEnd checks whether the decoder may be at the end of the stream.
+func (d *rangeDecoder) possiblyAtEnd() bool {
+	return d.code == 0
+}
+
+// DirectDecodeBit decodes a bit with probability 1/2. The return value b will
+// contain the bit at the least-significant position. All other bits will be
+// zero.
+func (d *rangeDecoder) DirectDecodeBit() (b uint32, err error) {
+	d.nrange >>= 1
+	d.code -= d.nrange
+	t := 0 - (d.code >> 31)
+	d.code += d.nrange & t
+	b = (t + 1) & 1
+
+	// d.code will stay less then d.nrange
+
+	// normalize
+	// assume d.code < d.nrange
+	const top = 1 << 24
+	if d.nrange >= top {
+		return b, nil
+	}
+	d.nrange <<= 8
+	// d.code < d.nrange will be maintained
+	return b, d.updateCode()
+}
+
+// decodeBit decodes a single bit. The bit will be returned at the
+// least-significant position. All other bits will be zero. The probability
+// value will be updated.
+func (d *rangeDecoder) DecodeBit(p *prob) (b uint32, err error) {
+	bound := p.bound(d.nrange)
+	if d.code < bound {
+		d.nrange = bound
+		p.inc()
+		b = 0
+	} else {
+		d.code -= bound
+		d.nrange -= bound
+		p.dec()
+		b = 1
+	}
+	// normalize
+	// assume d.code < d.nrange
+	const top = 1 << 24
+	if d.nrange >= top {
+		return b, nil
+	}
+	d.nrange <<= 8
+	// d.code < d.nrange will be maintained
+	return b, d.updateCode()
+}
+
+// updateCode reads a new byte into the code.
+func (d *rangeDecoder) updateCode() error {
+	b, err := d.br.ReadByte()
+	if err != nil {
+		return err
+	}
+	d.code = (d.code << 8) | uint32(b)
+	return nil
+}

vendor/github.com/ulikunitz/xz/lzma/reader.go

@@ -0,0 +1,100 @@
+// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package lzma supports the decoding and encoding of LZMA streams.
+// Reader and Writer support the classic LZMA format. Reader2 and
+// Writer2 support the decoding and encoding of LZMA2 streams.
+//
+// The package is written completely in Go and doesn't rely on any external
+// library.
+package lzma
+
+import (
+	"errors"
+	"io"
+)
+
+// ReaderConfig stores the parameters for the reader of the classic LZMA
+// format.
+type ReaderConfig struct {
+	DictCap int
+}
+
+// fill converts the zero values of the configuration to the default values.
+func (c *ReaderConfig) fill() {
+	if c.DictCap == 0 {
+		c.DictCap = 8 * 1024 * 1024
+	}
+}
+
+// Verify checks the reader configuration for errors. Zero values will
+// be replaced by default values.
+func (c *ReaderConfig) Verify() error {
+	c.fill()
+	if !(MinDictCap <= c.DictCap && int64(c.DictCap) <= MaxDictCap) {
+		return errors.New("lzma: dictionary capacity is out of range")
+	}
+	return nil
+}
+
+// Reader provides a reader for LZMA files or streams.
+type Reader struct {
+	lzma io.Reader
+	h    header
+	d    *decoder
+}
+
+// NewReader creates a new reader for an LZMA stream using the classic
+// format. NewReader reads and checks the header of the LZMA stream.
+func NewReader(lzma io.Reader) (r *Reader, err error) {
+	return ReaderConfig{}.NewReader(lzma)
+}
+
+// NewReader creates a new reader for an LZMA stream in the classic
+// format. The function reads and verifies the the header of the LZMA
+// stream.
+func (c ReaderConfig) NewReader(lzma io.Reader) (r *Reader, err error) {
+	if err = c.Verify(); err != nil {
+		return nil, err
+	}
+	data := make([]byte, HeaderLen)
+	if _, err := io.ReadFull(lzma, data); err != nil {
+		if err == io.EOF {
+			return nil, errors.New("lzma: unexpected EOF")
+		}
+		return nil, err
+	}
+	r = &Reader{lzma: lzma}
+	if err = r.h.unmarshalBinary(data); err != nil {
+		return nil, err
+	}
+	if r.h.dictCap < MinDictCap {
+		return nil, errors.New("lzma: dictionary capacity too small")
+	}
+	dictCap := r.h.dictCap
+	if c.DictCap > dictCap {
+		dictCap = c.DictCap
+	}
+
+	state := newState(r.h.properties)
+	dict, err := newDecoderDict(dictCap)
+	if err != nil {
+		return nil, err
+	}
+	r.d, err = newDecoder(ByteReader(lzma), state, dict, r.h.size)
+	if err != nil {
+		return nil, err
+	}
+	return r, nil
+}
+
+// EOSMarker indicates that an EOS marker has been encountered.
+func (r *Reader) EOSMarker() bool {
+	return r.d.eosMarker
+}
+
+// Read returns uncompressed data.
+func (r *Reader) Read(p []byte) (n int, err error) {
+	return r.d.Read(p)
+}

vendor/github.com/ulikunitz/xz/lzma/reader2.go

@@ -0,0 +1,232 @@
+// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package lzma
+
+import (
+	"errors"
+	"io"
+
+	"github.com/ulikunitz/xz/internal/xlog"
+)
+
+// Reader2Config stores the parameters for the LZMA2 reader.
+// format.
+type Reader2Config struct {
+	DictCap int
+}
+
+// fill converts the zero values of the configuration to the default values.
+func (c *Reader2Config) fill() {
+	if c.DictCap == 0 {
+		c.DictCap = 8 * 1024 * 1024
+	}
+}
+
+// Verify checks the reader configuration for errors. Zero configuration values
+// will be replaced by default values.
+func (c *Reader2Config) Verify() error {
+	c.fill()
+	if !(MinDictCap <= c.DictCap && int64(c.DictCap) <= MaxDictCap) {
+		return errors.New("lzma: dictionary capacity is out of range")
+	}
+	return nil
+}
+
+// Reader2 supports the reading of LZMA2 chunk sequences. Note that the
+// first chunk should have a dictionary reset and the first compressed
+// chunk a properties reset. The chunk sequence may not be terminated by
+// an end-of-stream chunk.
+type Reader2 struct {
+	r   io.Reader
+	err error
+
+	dict        *decoderDict
+	ur          *uncompressedReader
+	decoder     *decoder
+	chunkReader io.Reader
+
+	cstate chunkState
+	ctype  chunkType
+}
+
+// NewReader2 creates a reader for an LZMA2 chunk sequence.
+func NewReader2(lzma2 io.Reader) (r *Reader2, err error) {
+	return Reader2Config{}.NewReader2(lzma2)
+}
+
+// NewReader2 creates an LZMA2 reader using the given configuration.
+func (c Reader2Config) NewReader2(lzma2 io.Reader) (r *Reader2, err error) {
+	if err = c.Verify(); err != nil {
+		return nil, err
+	}
+	r = &Reader2{r: lzma2, cstate: start}
+	r.dict, err = newDecoderDict(c.DictCap)
+	if err != nil {
+		return nil, err
+	}
+	if err = r.startChunk(); err != nil {
+		r.err = err
+	}
+	return r, nil
+}
+
+// uncompressed tests whether the chunk type specifies an uncompressed
+// chunk.
+func uncompressed(ctype chunkType) bool {
+	return ctype == cU || ctype == cUD
+}
+
+// startChunk parses a new chunk.
+func (r *Reader2) startChunk() error {
+	r.chunkReader = nil
+	header, err := readChunkHeader(r.r)
+	if err != nil {
+		if err == io.EOF {
+			err = io.ErrUnexpectedEOF
+		}
+		return err
+	}
+	xlog.Debugf("chunk header %v", header)
+	if err = r.cstate.next(header.ctype); err != nil {
+		return err
+	}
+	if r.cstate == stop {
+		return io.EOF
+	}
+	if header.ctype == cUD || header.ctype == cLRND {
+		r.dict.Reset()
+	}
+	size := int64(header.uncompressed) + 1
+	if uncompressed(header.ctype) {
+		if r.ur != nil {
+			r.ur.Reopen(r.r, size)
+		} else {
+			r.ur = newUncompressedReader(r.r, r.dict, size)
+		}
+		r.chunkReader = r.ur
+		return nil
+	}
+	br := ByteReader(io.LimitReader(r.r, int64(header.compressed)+1))
+	if r.decoder == nil {
+		state := newState(header.props)
+		r.decoder, err = newDecoder(br, state, r.dict, size)
+		if err != nil {
+			return err
+		}
+		r.chunkReader = r.decoder
+		return nil
+	}
+	switch header.ctype {
+	case cLR:
+		r.decoder.State.Reset()
+	case cLRN, cLRND:
+		r.decoder.State = newState(header.props)
+	}
+	err = r.decoder.Reopen(br, size)
+	if err != nil {
+		return err
+	}
+	r.chunkReader = r.decoder
+	return nil
+}
+
+// Read reads data from the LZMA2 chunk sequence.
+func (r *Reader2) Read(p []byte) (n int, err error) {
+	if r.err != nil {
+		return 0, r.err
+	}
+	for n < len(p) {
+		var k int
+		k, err = r.chunkReader.Read(p[n:])
+		n += k
+		if err != nil {
+			if err == io.EOF {
+				err = r.startChunk()
+				if err == nil {
+					continue
+				}
+			}
+			r.err = err
+			return n, err
+		}
+		if k == 0 {
+			r.err = errors.New("lzma: Reader2 doesn't get data")
+			return n, r.err
+		}
+	}
+	return n, nil
+}
+
+// EOS returns whether the LZMA2 stream has been terminated by an
+// end-of-stream chunk.
+func (r *Reader2) EOS() bool {
+	return r.cstate == stop
+}
+
+// uncompressedReader is used to read uncompressed chunks.
+type uncompressedReader struct {
+	lr   io.LimitedReader
+	Dict *decoderDict
+	eof  bool
+	err  error
+}
+
+// newUncompressedReader initializes a new uncompressedReader.
+func newUncompressedReader(r io.Reader, dict *decoderDict, size int64) *uncompressedReader {
+	ur := &uncompressedReader{
+		lr:   io.LimitedReader{R: r, N: size},
+		Dict: dict,
+	}
+	return ur
+}
+
+// Reopen reinitializes an uncompressed reader.
+func (ur *uncompressedReader) Reopen(r io.Reader, size int64) {
+	ur.err = nil
+	ur.eof = false
+	ur.lr = io.LimitedReader{R: r, N: size}
+}
+
+// fill reads uncompressed data into the dictionary.
+func (ur *uncompressedReader) fill() error {
+	if !ur.eof {
+		n, err := io.CopyN(ur.Dict, &ur.lr, int64(ur.Dict.Available()))
+		if err != io.EOF {
+			return err
+		}
+		ur.eof = true
+		if n > 0 {
+			return nil
+		}
+	}
+	if ur.lr.N != 0 {
+		return io.ErrUnexpectedEOF
+	}
+	return io.EOF
+}
+
+// Read reads uncompressed data from the limited reader.
+func (ur *uncompressedReader) Read(p []byte) (n int, err error) {
+	if ur.err != nil {
+		return 0, ur.err
+	}
+	for {
+		var k int
+		k, err = ur.Dict.Read(p[n:])
+		n += k
+		if n >= len(p) {
+			return n, nil
+		}
+		if err != nil {
+			break
+		}
+		err = ur.fill()
+		if err != nil {
+			break
+		}
+	}
+	ur.err = err
+	return n, err
+}

vendor/github.com/ulikunitz/xz/lzma/reader_test.go

@@ -0,0 +1,312 @@
+// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package lzma
+
+import (
+	"bufio"
+	"bytes"
+	"io"
+	"io/ioutil"
+	"log"
+	"os"
+	"path/filepath"
+	"testing"
+	"testing/iotest"
+)
+
+func TestNewReader(t *testing.T) {
+	f, err := os.Open("examples/a.lzma")
+	if err != nil {
+		t.Fatalf("open examples/a.lzma: %s", err)
+	}
+	defer f.Close()
+	_, err = NewReader(bufio.NewReader(f))
+	if err != nil {
+		t.Fatalf("NewReader: %s", err)
+	}
+}
+
+const (
+	dirname  = "examples"
+	origname = "a.txt"
+)
+
+func readOrigFile(t *testing.T) []byte {
+	orig, err := ioutil.ReadFile(filepath.Join(dirname, origname))
+	if err != nil {
+		t.Fatalf("ReadFile: %s", err)
+	}
+	return orig
+}
+
+func testDecodeFile(t *testing.T, filename string, orig []byte) {
+	pathname := filepath.Join(dirname, filename)
+	f, err := os.Open(pathname)
+	if err != nil {
+		t.Fatalf("Open(%q): %s", pathname, err)
+	}
+	defer func() {
+		if err = f.Close(); err != nil {
+			t.Fatalf("f.Close() error %s", err)
+		}
+	}()
+	t.Logf("file %s opened", filename)
+	l, err := NewReader(bufio.NewReader(f))
+	if err != nil {
+		t.Fatalf("NewReader: %s", err)
+	}
+	decoded, err := ioutil.ReadAll(l)
+	if err != nil {
+		t.Fatalf("ReadAll: %s", err)
+	}
+	t.Logf("%s", decoded)
+	if len(orig) != len(decoded) {
+		t.Fatalf("length decoded is %d; want %d",
+			len(decoded), len(orig))
+	}
+	if !bytes.Equal(orig, decoded) {
+		t.Fatalf("decoded file differs from original")
+	}
+}
+
+func TestReaderSimple(t *testing.T) {
+	// DebugOn(os.Stderr)
+	// defer DebugOff()
+
+	testDecodeFile(t, "a.lzma", readOrigFile(t))
+}
+
+func TestReaderAll(t *testing.T) {
+	dirname := "examples"
+	dir, err := os.Open(dirname)
+	if err != nil {
+		t.Fatalf("Open: %s", err)
+	}
+	defer func() {
+		if err := dir.Close(); err != nil {
+			t.Fatalf("dir.Close() error %s", err)
+		}
+	}()
+	all, err := dir.Readdirnames(0)
+	if err != nil {
+		t.Fatalf("Readdirnames: %s", err)
+	}
+	// filter now all file with the pattern "a*.lzma"
+	files := make([]string, 0, len(all))
+	for _, fn := range all {
+		match, err := filepath.Match("a*.lzma", fn)
+		if err != nil {
+			t.Fatalf("Match: %s", err)
+		}
+		if match {
+			files = append(files, fn)
+		}
+	}
+	t.Log("files:", files)
+	orig := readOrigFile(t)
+	// actually test the files
+	for _, fn := range files {
+		testDecodeFile(t, fn, orig)
+	}
+}
+
+//
+func Example_reader() {
+	f, err := os.Open("fox.lzma")
+	if err != nil {
+		log.Fatal(err)
+	}
+	// no need for defer; Fatal calls os.Exit(1) that doesn't execute deferred functions
+	r, err := NewReader(bufio.NewReader(f))
+	if err != nil {
+		log.Fatal(err)
+	}
+	_, err = io.Copy(os.Stdout, r)
+	if err != nil {
+		log.Fatal(err)
+	}
+	if err := f.Close(); err != nil {
+		log.Fatal(err)
+	}
+	// Output:
+	// The quick brown fox jumps over the lazy dog.
+}
+
+type wrapTest struct {
+	name string
+	wrap func(io.Reader) io.Reader
+}
+
+func (w *wrapTest) testFile(t *testing.T, filename string, orig []byte) {
+	pathname := filepath.Join(dirname, filename)
+	f, err := os.Open(pathname)
+	if err != nil {
+		t.Fatalf("Open(\"%s\"): %s", pathname, err)
+	}
+	defer func() {
+		if err := f.Close(); err != nil {
+			log.Fatal(err)
+		}
+	}()
+	t.Logf("%s file %s opened", w.name, filename)
+	l, err := NewReader(w.wrap(f))
+	if err != nil {
+		t.Fatalf("%s NewReader: %s", w.name, err)
+	}
+	decoded, err := ioutil.ReadAll(l)
+	if err != nil {
+		t.Fatalf("%s ReadAll: %s", w.name, err)
+	}
+	t.Logf("%s", decoded)
+	if len(orig) != len(decoded) {
+		t.Fatalf("%s length decoded is %d; want %d",
+			w.name, len(decoded), len(orig))
+	}
+	if !bytes.Equal(orig, decoded) {
+		t.Fatalf("%s decoded file differs from original", w.name)
+	}
+}
+
+func TestReaderWrap(t *testing.T) {
+	tests := [...]wrapTest{
+		{"DataErrReader", iotest.DataErrReader},
+		{"HalfReader", iotest.HalfReader},
+		{"OneByteReader", iotest.OneByteReader},
+		// TimeOutReader would require buffer
+	}
+	orig := readOrigFile(t)
+	for _, tst := range tests {
+		tst.testFile(t, "a.lzma", orig)
+	}
+}
+
+func TestReaderBadFiles(t *testing.T) {
+	dirname := "examples"
+	dir, err := os.Open(dirname)
+	if err != nil {
+		t.Fatalf("Open: %s", err)
+	}
+	defer func() {
+		if err := dir.Close(); err != nil {
+			t.Fatalf("dir.Close() error %s", err)
+		}
+	}()
+	all, err := dir.Readdirnames(0)
+	if err != nil {
+		t.Fatalf("Readdirnames: %s", err)
+	}
+	// filter now all file with the pattern "bad*.lzma"
+	files := make([]string, 0, len(all))
+	for _, fn := range all {
+		match, err := filepath.Match("bad*.lzma", fn)
+		if err != nil {
+			t.Fatalf("Match: %s", err)
+		}
+		if match {
+			files = append(files, fn)
+		}
+	}
+	t.Log("files:", files)
+	for _, filename := range files {
+		pathname := filepath.Join(dirname, filename)
+		f, err := os.Open(pathname)
+		if err != nil {
+			t.Fatalf("Open(\"%s\"): %s", pathname, err)
+		}
+		defer func(f *os.File) {
+			if err := f.Close(); err != nil {
+				t.Fatalf("f.Close() error %s", err)
+			}
+		}(f)
+		t.Logf("file %s opened", filename)
+		l, err := NewReader(f)
+		if err != nil {
+			t.Fatalf("NewReader: %s", err)
+		}
+		decoded, err := ioutil.ReadAll(l)
+		if err == nil {
+			t.Errorf("ReadAll for %s: no error", filename)
+			t.Logf("%s", decoded)
+			continue
+		}
+		t.Logf("%s: error %s", filename, err)
+	}
+}
+
+type repReader byte
+
+func (r repReader) Read(p []byte) (n int, err error) {
+	for i := range p {
+		p[i] = byte(r)
+	}
+	return len(p), nil
+}
+
+func newRepReader(c byte, n int64) *io.LimitedReader {
+	return &io.LimitedReader{R: repReader(c), N: n}
+}
+
+func newCodeReader(r io.Reader) *io.PipeReader {
+	pr, pw := io.Pipe()
+	go func() {
+		bw := bufio.NewWriter(pw)
+		lw, err := NewWriter(bw)
+		if err != nil {
+			log.Fatalf("NewWriter error %s", err)
+		}
+		if _, err = io.Copy(lw, r); err != nil {
+			log.Fatalf("io.Copy error %s", err)
+		}
+		if err = lw.Close(); err != nil {
+			log.Fatalf("lw.Close error %s", err)
+		}
+		if err = bw.Flush(); err != nil {
+			log.Fatalf("bw.Flush() error %s", err)
+		}
+		if err = pw.CloseWithError(io.EOF); err != nil {
+			log.Fatalf("pw.CloseWithError(io.EOF) error %s", err)
+		}
+	}()
+	return pr
+}
+
+func TestReaderErrAgain(t *testing.T) {
+	lengths := []int64{0, 128, 1024, 4095, 4096, 4097, 8191, 8192, 8193}
+	buf := make([]byte, 128)
+	const c = 'A'
+	for _, n := range lengths {
+		t.Logf("n: %d", n)
+		pr := newCodeReader(newRepReader(c, n))
+		r, err := NewReader(pr)
+		if err != nil {
+			t.Fatalf("NewReader(pr) error %s", err)
+		}
+		k := int64(0)
+		for {
+			m, err := r.Read(buf)
+			k += int64(m)
+			if err == io.EOF {
+				break
+			}
+			if err != nil {
+				t.Errorf("r.Read(buf) error %s", err)
+				break
+			}
+			if m > len(buf) {
+				t.Fatalf("r.Read(buf) %d; want <= %d", m,
+					len(buf))
+			}
+			for i, b := range buf[:m] {
+				if b != c {
+					t.Fatalf("buf[%d]=%c; want %c", i, b,
+						c)
+				}
+			}
+		}
+		if k != n {
+			t.Errorf("Read %d bytes; want %d", k, n)
+		}
+	}
+}

vendor/github.com/ulikunitz/xz/lzma/state.go

@@ -0,0 +1,151 @@
+// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package lzma
+
+// states defines the overall state count
+const states = 12
+
+// State maintains the full state of the operation encoding or decoding
+// process.
+type state struct {
+	rep         [4]uint32
+	isMatch     [states << maxPosBits]prob
+	isRepG0Long [states << maxPosBits]prob
+	isRep       [states]prob
+	isRepG0     [states]prob
+	isRepG1     [states]prob
+	isRepG2     [states]prob
+	litCodec    literalCodec
+	lenCodec    lengthCodec
+	repLenCodec lengthCodec
+	distCodec   distCodec
+	state       uint32
+	posBitMask  uint32
+	Properties  Properties
+}
+
+// initProbSlice initializes a slice of probabilities.
+func initProbSlice(p []prob) {
+	for i := range p {
+		p[i] = probInit
+	}
+}
+
+// Reset sets all state information to the original values.
+func (s *state) Reset() {
+	p := s.Properties
+	*s = state{
+		Properties: p,
+		// dict:       s.dict,
+		posBitMask: (uint32(1) << uint(p.PB)) - 1,
+	}
+	initProbSlice(s.isMatch[:])
+	initProbSlice(s.isRep[:])
+	initProbSlice(s.isRepG0[:])
+	initProbSlice(s.isRepG1[:])
+	initProbSlice(s.isRepG2[:])
+	initProbSlice(s.isRepG0Long[:])
+	s.litCodec.init(p.LC, p.LP)
+	s.lenCodec.init()
+	s.repLenCodec.init()
+	s.distCodec.init()
+}
+
+// initState initializes the state.
+func initState(s *state, p Properties) {
+	*s = state{Properties: p}
+	s.Reset()
+}
+
+// newState creates a new state from the give Properties.
+func newState(p Properties) *state {
+	s := &state{Properties: p}
+	s.Reset()
+	return s
+}
+
+// deepcopy initializes s as a deep copy of the source.
+func (s *state) deepcopy(src *state) {
+	if s == src {
+		return
+	}
+	s.rep = src.rep
+	s.isMatch = src.isMatch
+	s.isRepG0Long = src.isRepG0Long
+	s.isRep = src.isRep
+	s.isRepG0 = src.isRepG0
+	s.isRepG1 = src.isRepG1
+	s.isRepG2 = src.isRepG2
+	s.litCodec.deepcopy(&src.litCodec)
+	s.lenCodec.deepcopy(&src.lenCodec)
+	s.repLenCodec.deepcopy(&src.repLenCodec)
+	s.distCodec.deepcopy(&src.distCodec)
+	s.state = src.state
+	s.posBitMask = src.posBitMask
+	s.Properties = src.Properties
+}
+
+// cloneState creates a new clone of the give state.
+func cloneState(src *state) *state {
+	s := new(state)
+	s.deepcopy(src)
+	return s
+}
+
+// updateStateLiteral updates the state for a literal.
+func (s *state) updateStateLiteral() {
+	switch {
+	case s.state < 4:
+		s.state = 0
+		return
+	case s.state < 10:
+		s.state -= 3
+		return
+	}
+	s.state -= 6
+}
+
+// updateStateMatch updates the state for a match.
+func (s *state) updateStateMatch() {
+	if s.state < 7 {
+		s.state = 7
+	} else {
+		s.state = 10
+	}
+}
+
+// updateStateRep updates the state for a repetition.
+func (s *state) updateStateRep() {
+	if s.state < 7 {
+		s.state = 8
+	} else {
+		s.state = 11
+	}
+}
+
+// updateStateShortRep updates the state for a short repetition.
+func (s *state) updateStateShortRep() {
+	if s.state < 7 {
+		s.state = 9
+	} else {
+		s.state = 11
+	}
+}
+
+// states computes the states of the operation codec.
+func (s *state) states(dictHead int64) (state1, state2, posState uint32) {
+	state1 = s.state
+	posState = uint32(dictHead) & s.posBitMask
+	state2 = (s.state << maxPosBits) | posState
+	return
+}
+
+// litState computes the literal state.
+func (s *state) litState(prev byte, dictHead int64) uint32 {
+	lp, lc := uint(s.Properties.LP), uint(s.Properties.LC)
+	litState := ((uint32(dictHead) & ((1 << lp) - 1)) << lc) |
+		(uint32(prev) >> (8 - lc))
+	return litState
+}

vendor/github.com/ulikunitz/xz/lzma/treecodecs.go

@@ -0,0 +1,133 @@
+// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package lzma
+
+// treeCodec encodes or decodes values with a fixed bit size. It is using a
+// tree of probability value. The root of the tree is the most-significant bit.
+type treeCodec struct {
+	probTree
+}
+
+// makeTreeCodec makes a tree codec. The bits value must be inside the range
+// [1,32].
+func makeTreeCodec(bits int) treeCodec {
+	return treeCodec{makeProbTree(bits)}
+}
+
+// deepcopy initializes tc as a deep copy of the source.
+func (tc *treeCodec) deepcopy(src *treeCodec) {
+	tc.probTree.deepcopy(&src.probTree)
+}
+
+// Encode uses the range encoder to encode a fixed-bit-size value.
+func (tc *treeCodec) Encode(e *rangeEncoder, v uint32) (err error) {
+	m := uint32(1)
+	for i := int(tc.bits) - 1; i >= 0; i-- {
+		b := (v >> uint(i)) & 1
+		if err := e.EncodeBit(b, &tc.probs[m]); err != nil {
+			return err
+		}
+		m = (m << 1) | b
+	}
+	return nil
+}
+
+// Decodes uses the range decoder to decode a fixed-bit-size value. Errors may
+// be caused by the range decoder.
+func (tc *treeCodec) Decode(d *rangeDecoder) (v uint32, err error) {
+	m := uint32(1)
+	for j := 0; j < int(tc.bits); j++ {
+		b, err := d.DecodeBit(&tc.probs[m])
+		if err != nil {
+			return 0, err
+		}
+		m = (m << 1) | b
+	}
+	return m - (1 << uint(tc.bits)), nil
+}
+
+// treeReverseCodec is another tree codec, where the least-significant bit is
+// the start of the probability tree.
+type treeReverseCodec struct {
+	probTree
+}
+
+// deepcopy initializes the treeReverseCodec as a deep copy of the
+// source.
+func (tc *treeReverseCodec) deepcopy(src *treeReverseCodec) {
+	tc.probTree.deepcopy(&src.probTree)
+}
+
+// makeTreeReverseCodec creates treeReverseCodec value. The bits argument must
+// be in the range [1,32].
+func makeTreeReverseCodec(bits int) treeReverseCodec {
+	return treeReverseCodec{makeProbTree(bits)}
+}
+
+// Encode uses range encoder to encode a fixed-bit-size value. The range
+// encoder may cause errors.
+func (tc *treeReverseCodec) Encode(v uint32, e *rangeEncoder) (err error) {
+	m := uint32(1)
+	for i := uint(0); i < uint(tc.bits); i++ {
+		b := (v >> i) & 1
+		if err := e.EncodeBit(b, &tc.probs[m]); err != nil {
+			return err
+		}
+		m = (m << 1) | b
+	}
+	return nil
+}
+
+// Decodes uses the range decoder to decode a fixed-bit-size value. Errors
+// returned by the range decoder will be returned.
+func (tc *treeReverseCodec) Decode(d *rangeDecoder) (v uint32, err error) {
+	m := uint32(1)
+	for j := uint(0); j < uint(tc.bits); j++ {
+		b, err := d.DecodeBit(&tc.probs[m])
+		if err != nil {
+			return 0, err
+		}
+		m = (m << 1) | b
+		v |= b << j
+	}
+	return v, nil
+}
+
+// probTree stores enough probability values to be used by the treeEncode and
+// treeDecode methods of the range coder types.
+type probTree struct {
+	probs []prob
+	bits  byte
+}
+
+// deepcopy initializes the probTree value as a deep copy of the source.
+func (t *probTree) deepcopy(src *probTree) {
+	if t == src {
+		return
+	}
+	t.probs = make([]prob, len(src.probs))
+	copy(t.probs, src.probs)
+	t.bits = src.bits
+}
+
+// makeProbTree initializes a probTree structure.
+func makeProbTree(bits int) probTree {
+	if !(1 <= bits && bits <= 32) {
+		panic("bits outside of range [1,32]")
+	}
+	t := probTree{
+		bits:  byte(bits),
+		probs: make([]prob, 1<<uint(bits)),
+	}
+	for i := range t.probs {
+		t.probs[i] = probInit
+	}
+	return t
+}
+
+// Bits provides the number of bits for the values to de- or encode.
+func (t *probTree) Bits() int {
+	return int(t.bits)
+}

vendor/github.com/ulikunitz/xz/lzma/writer.go

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

vendor/github.com/ulikunitz/xz/lzma/writer2.go

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

vendor/github.com/ulikunitz/xz/lzma/writer2_test.go

@@ -0,0 +1,109 @@
+// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package lzma
+
+import (
+	"bytes"
+	"io"
+	"math/rand"
+	"strings"
+	"testing"
+
+	"github.com/ulikunitz/xz/internal/randtxt"
+)
+
+func TestWriter2(t *testing.T) {
+	var buf bytes.Buffer
+	w, err := Writer2Config{DictCap: 4096}.NewWriter2(&buf)
+	if err != nil {
+		t.Fatalf("NewWriter error %s", err)
+	}
+	n, err := w.Write([]byte{'a'})
+	if err != nil {
+		t.Fatalf("w.Write([]byte{'a'}) error %s", err)
+	}
+	if n != 1 {
+		t.Fatalf("w.Write([]byte{'a'}) returned %d; want %d", n, 1)
+	}
+	if err = w.Flush(); err != nil {
+		t.Fatalf("w.Flush() error %s", err)
+	}
+	// check that double Flush doesn't write another chunk
+	if err = w.Flush(); err != nil {
+		t.Fatalf("w.Flush() error %s", err)
+	}
+	if err = w.Close(); err != nil {
+		t.Fatalf("w.Close() error %s", err)
+	}
+	p := buf.Bytes()
+	want := []byte{1, 0, 0, 'a', 0}
+	if !bytes.Equal(p, want) {
+		t.Fatalf("bytes written %#v; want %#v", p, want)
+	}
+}
+
+func TestCycle1(t *testing.T) {
+	var buf bytes.Buffer
+	w, err := Writer2Config{DictCap: 4096}.NewWriter2(&buf)
+	if err != nil {
+		t.Fatalf("NewWriter error %s", err)
+	}
+	n, err := w.Write([]byte{'a'})
+	if err != nil {
+		t.Fatalf("w.Write([]byte{'a'}) error %s", err)
+	}
+	if n != 1 {
+		t.Fatalf("w.Write([]byte{'a'}) returned %d; want %d", n, 1)
+	}
+	if err = w.Close(); err != nil {
+		t.Fatalf("w.Close() error %s", err)
+	}
+	r, err := Reader2Config{DictCap: 4096}.NewReader2(&buf)
+	if err != nil {
+		t.Fatalf("NewReader error %s", err)
+	}
+	p := make([]byte, 3)
+	n, err = r.Read(p)
+	t.Logf("n %d error %v", n, err)
+}
+
+func TestCycle2(t *testing.T) {
+	buf := new(bytes.Buffer)
+	w, err := Writer2Config{DictCap: 4096}.NewWriter2(buf)
+	if err != nil {
+		t.Fatalf("NewWriter error %s", err)
+	}
+	// const txtlen = 1024
+	const txtlen = 2100000
+	io.CopyN(buf, randtxt.NewReader(rand.NewSource(42)), txtlen)
+	txt := buf.String()
+	buf.Reset()
+	n, err := io.Copy(w, strings.NewReader(txt))
+	if err != nil {
+		t.Fatalf("Compressing copy error %s", err)
+	}
+	if n != txtlen {
+		t.Fatalf("Compressing data length %d; want %d", n, txtlen)
+	}
+	if err = w.Close(); err != nil {
+		t.Fatalf("w.Close error %s", err)
+	}
+	t.Logf("buf.Len() %d", buf.Len())
+	r, err := Reader2Config{DictCap: 4096}.NewReader2(buf)
+	if err != nil {
+		t.Fatalf("NewReader error %s", err)
+	}
+	out := new(bytes.Buffer)
+	n, err = io.Copy(out, r)
+	if err != nil {
+		t.Fatalf("Decompressing copy error %s after %d bytes", err, n)
+	}
+	if n != txtlen {
+		t.Fatalf("Decompression data length %d; want %d", n, txtlen)
+	}
+	if txt != out.String() {
+		t.Fatal("decompressed data differs from original")
+	}
+}

vendor/github.com/ulikunitz/xz/lzma/writer_test.go

@@ -0,0 +1,249 @@
+// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package lzma
+
+import (
+	"bufio"
+	"bytes"
+	"io"
+	"io/ioutil"
+	"log"
+	"math/rand"
+	"os"
+	"testing"
+
+	"github.com/ulikunitz/xz/internal/randtxt"
+)
+
+func TestWriterCycle(t *testing.T) {
+	orig := readOrigFile(t)
+	buf := new(bytes.Buffer)
+	w, err := NewWriter(buf)
+	if err != nil {
+		t.Fatalf("NewWriter: error %s", err)
+	}
+	n, err := w.Write(orig)
+	if err != nil {
+		t.Fatalf("w.Write error %s", err)
+	}
+	if n != len(orig) {
+		t.Fatalf("w.Write returned %d; want %d", n, len(orig))
+	}
+	if err = w.Close(); err != nil {
+		t.Fatalf("w.Close error %s", err)
+	}
+	t.Logf("buf.Len() %d len(orig) %d", buf.Len(), len(orig))
+	if buf.Len() > len(orig) {
+		t.Errorf("buf.Len()=%d bigger then len(orig)=%d", buf.Len(),
+			len(orig))
+	}
+	lr, err := NewReader(buf)
+	if err != nil {
+		t.Fatalf("NewReader error %s", err)
+	}
+	decoded, err := ioutil.ReadAll(lr)
+	if err != nil {
+		t.Fatalf("ReadAll(lr) error %s", err)
+	}
+	t.Logf("%s", decoded)
+	if len(orig) != len(decoded) {
+		t.Fatalf("length decoded is %d; want %d", len(decoded),
+			len(orig))
+	}
+	if !bytes.Equal(orig, decoded) {
+		t.Fatalf("decoded file differs from original")
+	}
+}
+
+func TestWriterLongData(t *testing.T) {
+	const (
+		seed = 49
+		size = 82237
+	)
+	r := io.LimitReader(randtxt.NewReader(rand.NewSource(seed)), size)
+	txt, err := ioutil.ReadAll(r)
+	if err != nil {
+		t.Fatalf("ReadAll error %s", err)
+	}
+	if len(txt) != size {
+		t.Fatalf("ReadAll read %d bytes; want %d", len(txt), size)
+	}
+	buf := &bytes.Buffer{}
+	w, err := WriterConfig{DictCap: 0x4000}.NewWriter(buf)
+	if err != nil {
+		t.Fatalf("WriterConfig.NewWriter error %s", err)
+	}
+	n, err := w.Write(txt)
+	if err != nil {
+		t.Fatalf("w.Write error %s", err)
+	}
+	if n != len(txt) {
+		t.Fatalf("w.Write wrote %d bytes; want %d", n, size)
+	}
+	if err = w.Close(); err != nil {
+		t.Fatalf("w.Close error %s", err)
+	}
+	t.Logf("compressed length %d", buf.Len())
+	lr, err := NewReader(buf)
+	if err != nil {
+		t.Fatalf("NewReader error %s", err)
+	}
+	txtRead, err := ioutil.ReadAll(lr)
+	if err != nil {
+		t.Fatalf("ReadAll(lr) error %s", err)
+	}
+	if len(txtRead) != size {
+		t.Fatalf("ReadAll(lr) returned %d bytes; want %d",
+			len(txtRead), size)
+	}
+	if !bytes.Equal(txtRead, txt) {
+		t.Fatal("ReadAll(lr) returned txt differs from origin")
+	}
+}
+
+func TestWriter_Size(t *testing.T) {
+	buf := new(bytes.Buffer)
+	w, err := WriterConfig{Size: 10, EOSMarker: true}.NewWriter(buf)
+	if err != nil {
+		t.Fatalf("WriterConfig.NewWriter error %s", err)
+	}
+	q := []byte{'a'}
+	for i := 0; i < 9; i++ {
+		n, err := w.Write(q)
+		if err != nil {
+			t.Fatalf("w.Write error %s", err)
+		}
+		if n != 1 {
+			t.Fatalf("w.Write returned %d; want %d", n, 1)
+		}
+		q[0]++
+	}
+	if err := w.Close(); err != errSize {
+		t.Fatalf("expected errSize, but got %v", err)
+	}
+	n, err := w.Write(q)
+	if err != nil {
+		t.Fatalf("w.Write error %s", err)
+	}
+	if n != 1 {
+		t.Fatalf("w.Write returned %d; want %d", n, 1)
+	}
+	if err = w.Close(); err != nil {
+		t.Fatalf("w.Close error %s", err)
+	}
+	t.Logf("compressed size %d", buf.Len())
+	r, err := NewReader(buf)
+	if err != nil {
+		t.Fatalf("NewReader error %s", err)
+	}
+	b, err := ioutil.ReadAll(r)
+	if err != nil {
+		t.Fatalf("ReadAll error %s", err)
+	}
+	s := string(b)
+	want := "abcdefghij"
+	if s != want {
+		t.Fatalf("read %q, want %q", s, want)
+	}
+}
+
+// The example uses the buffered reader and writer from package bufio.
+func Example_writer() {
+	pr, pw := io.Pipe()
+	go func() {
+		bw := bufio.NewWriter(pw)
+		w, err := NewWriter(bw)
+		if err != nil {
+			log.Fatal(err)
+		}
+		input := []byte("The quick brown fox jumps over the lazy dog.")
+		if _, err = w.Write(input); err != nil {
+			log.Fatal(err)
+		}
+		if err = w.Close(); err != nil {
+			log.Fatal(err)
+		}
+		// reader waits for the data
+		if err = bw.Flush(); err != nil {
+			log.Fatal(err)
+		}
+	}()
+	r, err := NewReader(pr)
+	if err != nil {
+		log.Fatal(err)
+	}
+	_, err = io.Copy(os.Stdout, r)
+	if err != nil {
+		log.Fatal(err)
+	}
+	// Output:
+	// The quick brown fox jumps over the lazy dog.
+}
+
+func BenchmarkReader(b *testing.B) {
+	const (
+		seed = 49
+		size = 50000
+	)
+	r := io.LimitReader(randtxt.NewReader(rand.NewSource(seed)), size)
+	txt, err := ioutil.ReadAll(r)
+	if err != nil {
+		b.Fatalf("ReadAll error %s", err)
+	}
+	buf := &bytes.Buffer{}
+	w, err := WriterConfig{DictCap: 0x4000}.NewWriter(buf)
+	if err != nil {
+		b.Fatalf("WriterConfig{}.NewWriter error %s", err)
+	}
+	if _, err = w.Write(txt); err != nil {
+		b.Fatalf("w.Write error %s", err)
+	}
+	if err = w.Close(); err != nil {
+		b.Fatalf("w.Close error %s", err)
+	}
+	data, err := ioutil.ReadAll(buf)
+	if err != nil {
+		b.Fatalf("ReadAll error %s", err)
+	}
+	b.SetBytes(int64(len(txt)))
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		lr, err := NewReader(bytes.NewReader(data))
+		if err != nil {
+			b.Fatalf("NewReader error %s", err)
+		}
+		if _, err = ioutil.ReadAll(lr); err != nil {
+			b.Fatalf("ReadAll(lr) error %s", err)
+		}
+	}
+}
+
+func BenchmarkWriter(b *testing.B) {
+	const (
+		seed = 49
+		size = 50000
+	)
+	r := io.LimitReader(randtxt.NewReader(rand.NewSource(seed)), size)
+	txt, err := ioutil.ReadAll(r)
+	if err != nil {
+		b.Fatalf("ReadAll error %s", err)
+	}
+	buf := &bytes.Buffer{}
+	b.SetBytes(int64(len(txt)))
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		buf.Reset()
+		w, err := WriterConfig{DictCap: 0x4000}.NewWriter(buf)
+		if err != nil {
+			b.Fatalf("NewWriter error %s", err)
+		}
+		if _, err = w.Write(txt); err != nil {
+			b.Fatalf("w.Write error %s", err)
+		}
+		if err = w.Close(); err != nil {
+			b.Fatalf("w.Close error %s", err)
+		}
+	}
+}

vendor/github.com/ulikunitz/xz/lzmafilter.go

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

vendor/github.com/ulikunitz/xz/make-docs

@@ -0,0 +1,5 @@
+#!/bin/sh
+
+set -x
+pandoc -t html5 -f markdown -s --css=doc/md.css -o README.html README.md
+pandoc -t html5 -f markdown -s --css=doc/md.css -o TODO.html TODO.md

vendor/github.com/ulikunitz/xz/reader.go

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

vendor/github.com/ulikunitz/xz/reader_test.go

@@ -0,0 +1,81 @@
+// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package xz
+
+import (
+	"bytes"
+	"io"
+	"io/ioutil"
+	"os"
+	"testing"
+)
+
+func TestReaderSimple(t *testing.T) {
+	const file = "fox.xz"
+	xz, err := os.Open(file)
+	if err != nil {
+		t.Fatalf("os.Open(%q) error %s", file, err)
+	}
+	r, err := NewReader(xz)
+	if err != nil {
+		t.Fatalf("NewReader error %s", err)
+	}
+	var buf bytes.Buffer
+	if _, err = io.Copy(&buf, r); err != nil {
+		t.Fatalf("io.Copy error %s", err)
+	}
+}
+
+func TestReaderSingleStream(t *testing.T) {
+	data, err := ioutil.ReadFile("fox.xz")
+	if err != nil {
+		t.Fatalf("ReadFile error %s", err)
+	}
+	xz := bytes.NewReader(data)
+	rc := ReaderConfig{SingleStream: true}
+	r, err := rc.NewReader(xz)
+	if err != nil {
+		t.Fatalf("NewReader error %s", err)
+	}
+	var buf bytes.Buffer
+	if _, err = io.Copy(&buf, r); err != nil {
+		t.Fatalf("io.Copy error %s", err)
+	}
+	buf.Reset()
+	data = append(data, 0)
+	xz = bytes.NewReader(data)
+	r, err = rc.NewReader(xz)
+	if err != nil {
+		t.Fatalf("NewReader error %s", err)
+	}
+	if _, err = io.Copy(&buf, r); err != errUnexpectedData {
+		t.Fatalf("io.Copy returned %v; want %v", err, errUnexpectedData)
+	}
+}
+
+func TestReaaderMultipleStreams(t *testing.T) {
+	data, err := ioutil.ReadFile("fox.xz")
+	if err != nil {
+		t.Fatalf("ReadFile error %s", err)
+	}
+	m := make([]byte, 0, 4*len(data)+4*4)
+	m = append(m, data...)
+	m = append(m, data...)
+	m = append(m, 0, 0, 0, 0)
+	m = append(m, data...)
+	m = append(m, 0, 0, 0, 0)
+	m = append(m, 0, 0, 0, 0)
+	m = append(m, data...)
+	m = append(m, 0, 0, 0, 0)
+	xz := bytes.NewReader(m)
+	r, err := NewReader(xz)
+	if err != nil {
+		t.Fatalf("NewReader error %s", err)
+	}
+	var buf bytes.Buffer
+	if _, err = io.Copy(&buf, r); err != nil {
+		t.Fatalf("io.Copy error %s", err)
+	}
+}

vendor/github.com/ulikunitz/xz/writer.go

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

vendor/github.com/ulikunitz/xz/writer_test.go

@@ -0,0 +1,138 @@
+// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package xz
+
+import (
+	"bytes"
+	"io"
+	"log"
+	"math/rand"
+	"os"
+	"testing"
+
+	"github.com/ulikunitz/xz/internal/randtxt"
+)
+
+func TestWriter(t *testing.T) {
+	const text = "The quick brown fox jumps over the lazy dog."
+	var buf bytes.Buffer
+	w, err := NewWriter(&buf)
+	if err != nil {
+		t.Fatalf("NewWriter error %s", err)
+	}
+	n, err := io.WriteString(w, text)
+	if err != nil {
+		t.Fatalf("WriteString error %s", err)
+	}
+	if n != len(text) {
+		t.Fatalf("Writestring wrote %d bytes; want %d", n, len(text))
+	}
+	if err = w.Close(); err != nil {
+		t.Fatalf("w.Close error %s", err)
+	}
+	var out bytes.Buffer
+	r, err := NewReader(&buf)
+	if err != nil {
+		t.Fatalf("NewReader error %s", err)
+	}
+	if _, err = io.Copy(&out, r); err != nil {
+		t.Fatalf("io.Copy error %s", err)
+	}
+	s := out.String()
+	if s != text {
+		t.Fatalf("reader decompressed to %q; want %q", s, text)
+	}
+}
+
+func TestIssue12(t *testing.T) {
+	var buf bytes.Buffer
+	w, err := NewWriter(&buf)
+	if err != nil {
+		t.Fatalf("NewWriter error %s", err)
+	}
+	if err = w.Close(); err != nil {
+		t.Fatalf("w.Close error %s", err)
+	}
+	r, err := NewReader(&buf)
+	if err != nil {
+		t.Fatalf("NewReader error %s", err)
+	}
+	var out bytes.Buffer
+	if _, err = io.Copy(&out, r); err != nil {
+		t.Fatalf("io.Copy error %s", err)
+	}
+	s := out.String()
+	if s != "" {
+		t.Fatalf("reader decompressed to %q; want %q", s, "")
+	}
+}
+
+func Example() {
+	const text = "The quick brown fox jumps over the lazy dog."
+	var buf bytes.Buffer
+
+	// compress text
+	w, err := NewWriter(&buf)
+	if err != nil {
+		log.Fatalf("NewWriter error %s", err)
+	}
+	if _, err := io.WriteString(w, text); err != nil {
+		log.Fatalf("WriteString error %s", err)
+	}
+	if err := w.Close(); err != nil {
+		log.Fatalf("w.Close error %s", err)
+	}
+
+	// decompress buffer and write result to stdout
+	r, err := NewReader(&buf)
+	if err != nil {
+		log.Fatalf("NewReader error %s", err)
+	}
+	if _, err = io.Copy(os.Stdout, r); err != nil {
+		log.Fatalf("io.Copy error %s", err)
+	}
+
+	// Output:
+	// The quick brown fox jumps over the lazy dog.
+}
+
+func TestWriter2(t *testing.T) {
+	const txtlen = 1023
+	var buf bytes.Buffer
+	io.CopyN(&buf, randtxt.NewReader(rand.NewSource(41)), txtlen)
+	txt := buf.String()
+
+	buf.Reset()
+	w, err := NewWriter(&buf)
+	if err != nil {
+		t.Fatalf("NewWriter error %s", err)
+	}
+	n, err := io.WriteString(w, txt)
+	if err != nil {
+		t.Fatalf("WriteString error %s", err)
+	}
+	if n != len(txt) {
+		t.Fatalf("WriteString wrote %d bytes; want %d", n, len(txt))
+	}
+	if err = w.Close(); err != nil {
+		t.Fatalf("Close error %s", err)
+	}
+	t.Logf("buf.Len() %d", buf.Len())
+	r, err := NewReader(&buf)
+	if err != nil {
+		t.Fatalf("NewReader error %s", err)
+	}
+	var out bytes.Buffer
+	k, err := io.Copy(&out, r)
+	if err != nil {
+		t.Fatalf("Decompressing copy error %s after %d bytes", err, n)
+	}
+	if k != txtlen {
+		t.Fatalf("Decompression data length %d; want %d", k, txtlen)
+	}
+	if txt != out.String() {
+		t.Fatal("decompressed data differs from original")
+	}
+}

vendor/golang.org/x/net/bpf/asm.go

@@ -0,0 +1,41 @@
+// Copyright 2016 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 bpf
+
+import "fmt"
+
+// Assemble converts insts into raw instructions suitable for loading
+// into a BPF virtual machine.
+//
+// Currently, no optimization is attempted, the assembled program flow
+// is exactly as provided.
+func Assemble(insts []Instruction) ([]RawInstruction, error) {
+	ret := make([]RawInstruction, len(insts))
+	var err error
+	for i, inst := range insts {
+		ret[i], err = inst.Assemble()
+		if err != nil {
+			return nil, fmt.Errorf("assembling instruction %d: %s", i+1, err)
+		}
+	}
+	return ret, nil
+}
+
+// Disassemble attempts to parse raw back into
+// Instructions. Unrecognized RawInstructions are assumed to be an
+// extension not implemented by this package, and are passed through
+// unchanged to the output. The allDecoded value reports whether insts
+// contains no RawInstructions.
+func Disassemble(raw []RawInstruction) (insts []Instruction, allDecoded bool) {
+	insts = make([]Instruction, len(raw))
+	allDecoded = true
+	for i, r := range raw {
+		insts[i] = r.Disassemble()
+		if _, ok := insts[i].(RawInstruction); ok {
+			allDecoded = false
+		}
+	}
+	return insts, allDecoded
+}

vendor/golang.org/x/net/bpf/constants.go

@@ -0,0 +1,218 @@
+// Copyright 2016 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 bpf
+
+// A Register is a register of the BPF virtual machine.
+type Register uint16
+
+const (
+	// RegA is the accumulator register. RegA is always the
+	// destination register of ALU operations.
+	RegA Register = iota
+	// RegX is the indirection register, used by LoadIndirect
+	// operations.
+	RegX
+)
+
+// An ALUOp is an arithmetic or logic operation.
+type ALUOp uint16
+
+// ALU binary operation types.
+const (
+	ALUOpAdd ALUOp = iota << 4
+	ALUOpSub
+	ALUOpMul
+	ALUOpDiv
+	ALUOpOr
+	ALUOpAnd
+	ALUOpShiftLeft
+	ALUOpShiftRight
+	aluOpNeg // Not exported because it's the only unary ALU operation, and gets its own instruction type.
+	ALUOpMod
+	ALUOpXor
+)
+
+// A JumpTest is a comparison operator used in conditional jumps.
+type JumpTest uint16
+
+// Supported operators for conditional jumps.
+const (
+	// K == A
+	JumpEqual JumpTest = iota
+	// K != A
+	JumpNotEqual
+	// K > A
+	JumpGreaterThan
+	// K < A
+	JumpLessThan
+	// K >= A
+	JumpGreaterOrEqual
+	// K <= A
+	JumpLessOrEqual
+	// K & A != 0
+	JumpBitsSet
+	// K & A == 0
+	JumpBitsNotSet
+)
+
+// An Extension is a function call provided by the kernel that
+// performs advanced operations that are expensive or impossible
+// within the BPF virtual machine.
+//
+// Extensions are only implemented by the Linux kernel.
+//
+// TODO: should we prune this list? Some of these extensions seem
+// either broken or near-impossible to use correctly, whereas other
+// (len, random, ifindex) are quite useful.
+type Extension int
+
+// Extension functions available in the Linux kernel.
+const (
+	// extOffset is the negative maximum number of instructions used
+	// to load instructions by overloading the K argument.
+	extOffset = -0x1000
+	// ExtLen returns the length of the packet.
+	ExtLen Extension = 1
+	// ExtProto returns the packet's L3 protocol type.
+	ExtProto Extension = 0
+	// ExtType returns the packet's type (skb->pkt_type in the kernel)
+	//
+	// TODO: better documentation. How nice an API do we want to
+	// provide for these esoteric extensions?
+	ExtType Extension = 4
+	// ExtPayloadOffset returns the offset of the packet payload, or
+	// the first protocol header that the kernel does not know how to
+	// parse.
+	ExtPayloadOffset Extension = 52
+	// ExtInterfaceIndex returns the index of the interface on which
+	// the packet was received.
+	ExtInterfaceIndex Extension = 8
+	// ExtNetlinkAttr returns the netlink attribute of type X at
+	// offset A.
+	ExtNetlinkAttr Extension = 12
+	// ExtNetlinkAttrNested returns the nested netlink attribute of
+	// type X at offset A.
+	ExtNetlinkAttrNested Extension = 16
+	// ExtMark returns the packet's mark value.
+	ExtMark Extension = 20
+	// ExtQueue returns the packet's assigned hardware queue.
+	ExtQueue Extension = 24
+	// ExtLinkLayerType returns the packet's hardware address type
+	// (e.g. Ethernet, Infiniband).
+	ExtLinkLayerType Extension = 28
+	// ExtRXHash returns the packets receive hash.
+	//
+	// TODO: figure out what this rxhash actually is.
+	ExtRXHash Extension = 32
+	// ExtCPUID returns the ID of the CPU processing the current
+	// packet.
+	ExtCPUID Extension = 36
+	// ExtVLANTag returns the packet's VLAN tag.
+	ExtVLANTag Extension = 44
+	// ExtVLANTagPresent returns non-zero if the packet has a VLAN
+	// tag.
+	//
+	// TODO: I think this might be a lie: it reads bit 0x1000 of the
+	// VLAN header, which changed meaning in recent revisions of the
+	// spec - this extension may now return meaningless information.
+	ExtVLANTagPresent Extension = 48
+	// ExtVLANProto returns 0x8100 if the frame has a VLAN header,
+	// 0x88a8 if the frame has a "Q-in-Q" double VLAN header, or some
+	// other value if no VLAN information is present.
+	ExtVLANProto Extension = 60
+	// ExtRand returns a uniformly random uint32.
+	ExtRand Extension = 56
+)
+
+// The following gives names to various bit patterns used in opcode construction.
+
+const (
+	opMaskCls uint16 = 0x7
+	// opClsLoad masks
+	opMaskLoadDest  = 0x01
+	opMaskLoadWidth = 0x18
+	opMaskLoadMode  = 0xe0
+	// opClsALU
+	opMaskOperandSrc = 0x08
+	opMaskOperator   = 0xf0
+	// opClsJump
+	opMaskJumpConst = 0x0f
+	opMaskJumpCond  = 0xf0
+)
+
+const (
+	// +---------------+-----------------+---+---+---+
+	// | AddrMode (3b) | LoadWidth (2b)  | 0 | 0 | 0 |
+	// +---------------+-----------------+---+---+---+
+	opClsLoadA uint16 = iota
+	// +---------------+-----------------+---+---+---+
+	// | AddrMode (3b) | LoadWidth (2b)  | 0 | 0 | 1 |
+	// +---------------+-----------------+---+---+---+
+	opClsLoadX
+	// +---+---+---+---+---+---+---+---+
+	// | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 |
+	// +---+---+---+---+---+---+---+---+
+	opClsStoreA
+	// +---+---+---+---+---+---+---+---+
+	// | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 |
+	// +---+---+---+---+---+---+---+---+
+	opClsStoreX
+	// +---------------+-----------------+---+---+---+
+	// | Operator (4b) | OperandSrc (1b) | 1 | 0 | 0 |
+	// +---------------+-----------------+---+---+---+
+	opClsALU
+	// +-----------------------------+---+---+---+---+
+	// |      TestOperator (4b)      | 0 | 1 | 0 | 1 |
+	// +-----------------------------+---+---+---+---+
+	opClsJump
+	// +---+-------------------------+---+---+---+---+
+	// | 0 | 0 | 0 |   RetSrc (1b)   | 0 | 1 | 1 | 0 |
+	// +---+-------------------------+---+---+---+---+
+	opClsReturn
+	// +---+-------------------------+---+---+---+---+
+	// | 0 | 0 | 0 |  TXAorTAX (1b)  | 0 | 1 | 1 | 1 |
+	// +---+-------------------------+---+---+---+---+
+	opClsMisc
+)
+
+const (
+	opAddrModeImmediate uint16 = iota << 5
+	opAddrModeAbsolute
+	opAddrModeIndirect
+	opAddrModeScratch
+	opAddrModePacketLen // actually an extension, not an addressing mode.
+	opAddrModeMemShift
+)
+
+const (
+	opLoadWidth4 uint16 = iota << 3
+	opLoadWidth2
+	opLoadWidth1
+)
+
+// Operator defined by ALUOp*
+
+const (
+	opALUSrcConstant uint16 = iota << 3
+	opALUSrcX
+)
+
+const (
+	opJumpAlways = iota << 4
+	opJumpEqual
+	opJumpGT
+	opJumpGE
+	opJumpSet
+)
+
+const (
+	opRetSrcConstant uint16 = iota << 4
+	opRetSrcA
+)
+
+const (
+	opMiscTAX = 0x00
+	opMiscTXA = 0x80
+)

vendor/golang.org/x/net/bpf/doc.go

@@ -0,0 +1,82 @@
+// Copyright 2016 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 bpf implements marshaling and unmarshaling of programs for the
+Berkeley Packet Filter virtual machine, and provides a Go implementation
+of the virtual machine.
+
+BPF's main use is to specify a packet filter for network taps, so that
+the kernel doesn't have to expensively copy every packet it sees to
+userspace. However, it's been repurposed to other areas where running
+user code in-kernel is needed. For example, Linux's seccomp uses BPF
+to apply security policies to system calls. For simplicity, this
+documentation refers only to packets, but other uses of BPF have their
+own data payloads.
+
+BPF programs run in a restricted virtual machine. It has almost no
+access to kernel functions, and while conditional branches are
+allowed, they can only jump forwards, to guarantee that there are no
+infinite loops.
+
+The virtual machine
+
+The BPF VM is an accumulator machine. Its main register, called
+register A, is an implicit source and destination in all arithmetic
+and logic operations. The machine also has 16 scratch registers for
+temporary storage, and an indirection register (register X) for
+indirect memory access. All registers are 32 bits wide.
+
+Each run of a BPF program is given one packet, which is placed in the
+VM's read-only "main memory". LoadAbsolute and LoadIndirect
+instructions can fetch up to 32 bits at a time into register A for
+examination.
+
+The goal of a BPF program is to produce and return a verdict (uint32),
+which tells the kernel what to do with the packet. In the context of
+packet filtering, the returned value is the number of bytes of the
+packet to forward to userspace, or 0 to ignore the packet. Other
+contexts like seccomp define their own return values.
+
+In order to simplify programs, attempts to read past the end of the
+packet terminate the program execution with a verdict of 0 (ignore
+packet). This means that the vast majority of BPF programs don't need
+to do any explicit bounds checking.
+
+In addition to the bytes of the packet, some BPF programs have access
+to extensions, which are essentially calls to kernel utility
+functions. Currently, the only extensions supported by this package
+are the Linux packet filter extensions.
+
+Examples
+
+This packet filter selects all ARP packets.
+
+	bpf.Assemble([]bpf.Instruction{
+		// Load "EtherType" field from the ethernet header.
+		bpf.LoadAbsolute{Off: 12, Size: 2},
+		// Skip over the next instruction if EtherType is not ARP.
+		bpf.JumpIf{Cond: bpf.JumpNotEqual, Val: 0x0806, SkipTrue: 1},
+		// Verdict is "send up to 4k of the packet to userspace."
+		bpf.RetConstant{Val: 4096},
+		// Verdict is "ignore packet."
+		bpf.RetConstant{Val: 0},
+	})
+
+This packet filter captures a random 1% sample of traffic.
+
+	bpf.Assemble([]bpf.Instruction{
+		// Get a 32-bit random number from the Linux kernel.
+		bpf.LoadExtension{Num: bpf.ExtRand},
+		// 1% dice roll?
+		bpf.JumpIf{Cond: bpf.JumpLessThan, Val: 2^32/100, SkipFalse: 1},
+		// Capture.
+		bpf.RetConstant{Val: 4096},
+		// Ignore.
+		bpf.RetConstant{Val: 0},
+	})
+
+*/
+package bpf // import "golang.org/x/net/bpf"

vendor/golang.org/x/net/bpf/instructions.go

@@ -0,0 +1,704 @@
+// Copyright 2016 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 bpf
+
+import "fmt"
+
+// An Instruction is one instruction executed by the BPF virtual
+// machine.
+type Instruction interface {
+	// Assemble assembles the Instruction into a RawInstruction.
+	Assemble() (RawInstruction, error)
+}
+
+// A RawInstruction is a raw BPF virtual machine instruction.
+type RawInstruction struct {
+	// Operation to execute.
+	Op uint16
+	// For conditional jump instructions, the number of instructions
+	// to skip if the condition is true/false.
+	Jt uint8
+	Jf uint8
+	// Constant parameter. The meaning depends on the Op.
+	K uint32
+}
+
+// Assemble implements the Instruction Assemble method.
+func (ri RawInstruction) Assemble() (RawInstruction, error) { return ri, nil }
+
+// Disassemble parses ri into an Instruction and returns it. If ri is
+// not recognized by this package, ri itself is returned.
+func (ri RawInstruction) Disassemble() Instruction {
+	switch ri.Op & opMaskCls {
+	case opClsLoadA, opClsLoadX:
+		reg := Register(ri.Op & opMaskLoadDest)
+		sz := 0
+		switch ri.Op & opMaskLoadWidth {
+		case opLoadWidth4:
+			sz = 4
+		case opLoadWidth2:
+			sz = 2
+		case opLoadWidth1:
+			sz = 1
+		default:
+			return ri
+		}
+		switch ri.Op & opMaskLoadMode {
+		case opAddrModeImmediate:
+			if sz != 4 {
+				return ri
+			}
+			return LoadConstant{Dst: reg, Val: ri.K}
+		case opAddrModeScratch:
+			if sz != 4 || ri.K > 15 {
+				return ri
+			}
+			return LoadScratch{Dst: reg, N: int(ri.K)}
+		case opAddrModeAbsolute:
+			if ri.K > extOffset+0xffffffff {
+				return LoadExtension{Num: Extension(-extOffset + ri.K)}
+			}
+			return LoadAbsolute{Size: sz, Off: ri.K}
+		case opAddrModeIndirect:
+			return LoadIndirect{Size: sz, Off: ri.K}
+		case opAddrModePacketLen:
+			if sz != 4 {
+				return ri
+			}
+			return LoadExtension{Num: ExtLen}
+		case opAddrModeMemShift:
+			return LoadMemShift{Off: ri.K}
+		default:
+			return ri
+		}
+
+	case opClsStoreA:
+		if ri.Op != opClsStoreA || ri.K > 15 {
+			return ri
+		}
+		return StoreScratch{Src: RegA, N: int(ri.K)}
+
+	case opClsStoreX:
+		if ri.Op != opClsStoreX || ri.K > 15 {
+			return ri
+		}
+		return StoreScratch{Src: RegX, N: int(ri.K)}
+
+	case opClsALU:
+		switch op := ALUOp(ri.Op & opMaskOperator); op {
+		case ALUOpAdd, ALUOpSub, ALUOpMul, ALUOpDiv, ALUOpOr, ALUOpAnd, ALUOpShiftLeft, ALUOpShiftRight, ALUOpMod, ALUOpXor:
+			if ri.Op&opMaskOperandSrc != 0 {
+				return ALUOpX{Op: op}
+			}
+			return ALUOpConstant{Op: op, Val: ri.K}
+		case aluOpNeg:
+			return NegateA{}
+		default:
+			return ri
+		}
+
+	case opClsJump:
+		if ri.Op&opMaskJumpConst != opClsJump {
+			return ri
+		}
+		switch ri.Op & opMaskJumpCond {
+		case opJumpAlways:
+			return Jump{Skip: ri.K}
+		case opJumpEqual:
+			if ri.Jt == 0 {
+				return JumpIf{
+					Cond:      JumpNotEqual,
+					Val:       ri.K,
+					SkipTrue:  ri.Jf,
+					SkipFalse: 0,
+				}
+			}
+			return JumpIf{
+				Cond:      JumpEqual,
+				Val:       ri.K,
+				SkipTrue:  ri.Jt,
+				SkipFalse: ri.Jf,
+			}
+		case opJumpGT:
+			if ri.Jt == 0 {
+				return JumpIf{
+					Cond:      JumpLessOrEqual,
+					Val:       ri.K,
+					SkipTrue:  ri.Jf,
+					SkipFalse: 0,
+				}
+			}
+			return JumpIf{
+				Cond:      JumpGreaterThan,
+				Val:       ri.K,
+				SkipTrue:  ri.Jt,
+				SkipFalse: ri.Jf,
+			}
+		case opJumpGE:
+			if ri.Jt == 0 {
+				return JumpIf{
+					Cond:      JumpLessThan,
+					Val:       ri.K,
+					SkipTrue:  ri.Jf,
+					SkipFalse: 0,
+				}
+			}
+			return JumpIf{
+				Cond:      JumpGreaterOrEqual,
+				Val:       ri.K,
+				SkipTrue:  ri.Jt,
+				SkipFalse: ri.Jf,
+			}
+		case opJumpSet:
+			return JumpIf{
+				Cond:      JumpBitsSet,
+				Val:       ri.K,
+				SkipTrue:  ri.Jt,
+				SkipFalse: ri.Jf,
+			}
+		default:
+			return ri
+		}
+
+	case opClsReturn:
+		switch ri.Op {
+		case opClsReturn | opRetSrcA:
+			return RetA{}
+		case opClsReturn | opRetSrcConstant:
+			return RetConstant{Val: ri.K}
+		default:
+			return ri
+		}
+
+	case opClsMisc:
+		switch ri.Op {
+		case opClsMisc | opMiscTAX:
+			return TAX{}
+		case opClsMisc | opMiscTXA:
+			return TXA{}
+		default:
+			return ri
+		}
+
+	default:
+		panic("unreachable") // switch is exhaustive on the bit pattern
+	}
+}
+
+// LoadConstant loads Val into register Dst.
+type LoadConstant struct {
+	Dst Register
+	Val uint32
+}
+
+// Assemble implements the Instruction Assemble method.
+func (a LoadConstant) Assemble() (RawInstruction, error) {
+	return assembleLoad(a.Dst, 4, opAddrModeImmediate, a.Val)
+}
+
+// String returns the instruction in assembler notation.
+func (a LoadConstant) String() string {
+	switch a.Dst {
+	case RegA:
+		return fmt.Sprintf("ld #%d", a.Val)
+	case RegX:
+		return fmt.Sprintf("ldx #%d", a.Val)
+	default:
+		return fmt.Sprintf("unknown instruction: %#v", a)
+	}
+}
+
+// LoadScratch loads scratch[N] into register Dst.
+type LoadScratch struct {
+	Dst Register
+	N   int // 0-15
+}
+
+// Assemble implements the Instruction Assemble method.
+func (a LoadScratch) Assemble() (RawInstruction, error) {
+	if a.N < 0 || a.N > 15 {
+		return RawInstruction{}, fmt.Errorf("invalid scratch slot %d", a.N)
+	}
+	return assembleLoad(a.Dst, 4, opAddrModeScratch, uint32(a.N))
+}
+
+// String returns the instruction in assembler notation.
+func (a LoadScratch) String() string {
+	switch a.Dst {
+	case RegA:
+		return fmt.Sprintf("ld M[%d]", a.N)
+	case RegX:
+		return fmt.Sprintf("ldx M[%d]", a.N)
+	default:
+		return fmt.Sprintf("unknown instruction: %#v", a)
+	}
+}
+
+// LoadAbsolute loads packet[Off:Off+Size] as an integer value into
+// register A.
+type LoadAbsolute struct {
+	Off  uint32
+	Size int // 1, 2 or 4
+}
+
+// Assemble implements the Instruction Assemble method.
+func (a LoadAbsolute) Assemble() (RawInstruction, error) {
+	return assembleLoad(RegA, a.Size, opAddrModeAbsolute, a.Off)
+}
+
+// String returns the instruction in assembler notation.
+func (a LoadAbsolute) String() string {
+	switch a.Size {
+	case 1: // byte
+		return fmt.Sprintf("ldb [%d]", a.Off)
+	case 2: // half word
+		return fmt.Sprintf("ldh [%d]", a.Off)
+	case 4: // word
+		if a.Off > extOffset+0xffffffff {
+			return LoadExtension{Num: Extension(a.Off + 0x1000)}.String()
+		}
+		return fmt.Sprintf("ld [%d]", a.Off)
+	default:
+		return fmt.Sprintf("unknown instruction: %#v", a)
+	}
+}
+
+// LoadIndirect loads packet[X+Off:X+Off+Size] as an integer value
+// into register A.
+type LoadIndirect struct {
+	Off  uint32
+	Size int // 1, 2 or 4
+}
+
+// Assemble implements the Instruction Assemble method.
+func (a LoadIndirect) Assemble() (RawInstruction, error) {
+	return assembleLoad(RegA, a.Size, opAddrModeIndirect, a.Off)
+}
+
+// String returns the instruction in assembler notation.
+func (a LoadIndirect) String() string {
+	switch a.Size {
+	case 1: // byte
+		return fmt.Sprintf("ldb [x + %d]", a.Off)
+	case 2: // half word
+		return fmt.Sprintf("ldh [x + %d]", a.Off)
+	case 4: // word
+		return fmt.Sprintf("ld [x + %d]", a.Off)
+	default:
+		return fmt.Sprintf("unknown instruction: %#v", a)
+	}
+}
+
+// LoadMemShift multiplies the first 4 bits of the byte at packet[Off]
+// by 4 and stores the result in register X.
+//
+// This instruction is mainly useful to load into X the length of an
+// IPv4 packet header in a single instruction, rather than have to do
+// the arithmetic on the header's first byte by hand.
+type LoadMemShift struct {
+	Off uint32
+}
+
+// Assemble implements the Instruction Assemble method.
+func (a LoadMemShift) Assemble() (RawInstruction, error) {
+	return assembleLoad(RegX, 1, opAddrModeMemShift, a.Off)
+}
+
+// String returns the instruction in assembler notation.
+func (a LoadMemShift) String() string {
+	return fmt.Sprintf("ldx 4*([%d]&0xf)", a.Off)
+}
+
+// LoadExtension invokes a linux-specific extension and stores the
+// result in register A.
+type LoadExtension struct {
+	Num Extension
+}
+
+// Assemble implements the Instruction Assemble method.
+func (a LoadExtension) Assemble() (RawInstruction, error) {
+	if a.Num == ExtLen {
+		return assembleLoad(RegA, 4, opAddrModePacketLen, 0)
+	}
+	return assembleLoad(RegA, 4, opAddrModeAbsolute, uint32(extOffset+a.Num))
+}
+
+// String returns the instruction in assembler notation.
+func (a LoadExtension) String() string {
+	switch a.Num {
+	case ExtLen:
+		return "ld #len"
+	case ExtProto:
+		return "ld #proto"
+	case ExtType:
+		return "ld #type"
+	case ExtPayloadOffset:
+		return "ld #poff"
+	case ExtInterfaceIndex:
+		return "ld #ifidx"
+	case ExtNetlinkAttr:
+		return "ld #nla"
+	case ExtNetlinkAttrNested:
+		return "ld #nlan"
+	case ExtMark:
+		return "ld #mark"
+	case ExtQueue:
+		return "ld #queue"
+	case ExtLinkLayerType:
+		return "ld #hatype"
+	case ExtRXHash:
+		return "ld #rxhash"
+	case ExtCPUID:
+		return "ld #cpu"
+	case ExtVLANTag:
+		return "ld #vlan_tci"
+	case ExtVLANTagPresent:
+		return "ld #vlan_avail"
+	case ExtVLANProto:
+		return "ld #vlan_tpid"
+	case ExtRand:
+		return "ld #rand"
+	default:
+		return fmt.Sprintf("unknown instruction: %#v", a)
+	}
+}
+
+// StoreScratch stores register Src into scratch[N].
+type StoreScratch struct {
+	Src Register
+	N   int // 0-15
+}
+
+// Assemble implements the Instruction Assemble method.
+func (a StoreScratch) Assemble() (RawInstruction, error) {
+	if a.N < 0 || a.N > 15 {
+		return RawInstruction{}, fmt.Errorf("invalid scratch slot %d", a.N)
+	}
+	var op uint16
+	switch a.Src {
+	case RegA:
+		op = opClsStoreA
+	case RegX:
+		op = opClsStoreX
+	default:
+		return RawInstruction{}, fmt.Errorf("invalid source register %v", a.Src)
+	}
+
+	return RawInstruction{
+		Op: op,
+		K:  uint32(a.N),
+	}, nil
+}
+
+// String returns the instruction in assembler notation.
+func (a StoreScratch) String() string {
+	switch a.Src {
+	case RegA:
+		return fmt.Sprintf("st M[%d]", a.N)
+	case RegX:
+		return fmt.Sprintf("stx M[%d]", a.N)
+	default:
+		return fmt.Sprintf("unknown instruction: %#v", a)
+	}
+}
+
+// ALUOpConstant executes A = A <Op> Val.
+type ALUOpConstant struct {
+	Op  ALUOp
+	Val uint32
+}
+
+// Assemble implements the Instruction Assemble method.
+func (a ALUOpConstant) Assemble() (RawInstruction, error) {
+	return RawInstruction{
+		Op: opClsALU | opALUSrcConstant | uint16(a.Op),
+		K:  a.Val,
+	}, nil
+}
+
+// String returns the instruction in assembler notation.
+func (a ALUOpConstant) String() string {
+	switch a.Op {
+	case ALUOpAdd:
+		return fmt.Sprintf("add #%d", a.Val)
+	case ALUOpSub:
+		return fmt.Sprintf("sub #%d", a.Val)
+	case ALUOpMul:
+		return fmt.Sprintf("mul #%d", a.Val)
+	case ALUOpDiv:
+		return fmt.Sprintf("div #%d", a.Val)
+	case ALUOpMod:
+		return fmt.Sprintf("mod #%d", a.Val)
+	case ALUOpAnd:
+		return fmt.Sprintf("and #%d", a.Val)
+	case ALUOpOr:
+		return fmt.Sprintf("or #%d", a.Val)
+	case ALUOpXor:
+		return fmt.Sprintf("xor #%d", a.Val)
+	case ALUOpShiftLeft:
+		return fmt.Sprintf("lsh #%d", a.Val)
+	case ALUOpShiftRight:
+		return fmt.Sprintf("rsh #%d", a.Val)
+	default:
+		return fmt.Sprintf("unknown instruction: %#v", a)
+	}
+}
+
+// ALUOpX executes A = A <Op> X
+type ALUOpX struct {
+	Op ALUOp
+}
+
+// Assemble implements the Instruction Assemble method.
+func (a ALUOpX) Assemble() (RawInstruction, error) {
+	return RawInstruction{
+		Op: opClsALU | opALUSrcX | uint16(a.Op),
+	}, nil
+}
+
+// String returns the instruction in assembler notation.
+func (a ALUOpX) String() string {
+	switch a.Op {
+	case ALUOpAdd:
+		return "add x"
+	case ALUOpSub:
+		return "sub x"
+	case ALUOpMul:
+		return "mul x"
+	case ALUOpDiv:
+		return "div x"
+	case ALUOpMod:
+		return "mod x"
+	case ALUOpAnd:
+		return "and x"
+	case ALUOpOr:
+		return "or x"
+	case ALUOpXor:
+		return "xor x"
+	case ALUOpShiftLeft:
+		return "lsh x"
+	case ALUOpShiftRight:
+		return "rsh x"
+	default:
+		return fmt.Sprintf("unknown instruction: %#v", a)
+	}
+}
+
+// NegateA executes A = -A.
+type NegateA struct{}
+
+// Assemble implements the Instruction Assemble method.
+func (a NegateA) Assemble() (RawInstruction, error) {
+	return RawInstruction{
+		Op: opClsALU | uint16(aluOpNeg),
+	}, nil
+}
+
+// String returns the instruction in assembler notation.
+func (a NegateA) String() string {
+	return fmt.Sprintf("neg")
+}
+
+// Jump skips the following Skip instructions in the program.
+type Jump struct {
+	Skip uint32
+}
+
+// Assemble implements the Instruction Assemble method.
+func (a Jump) Assemble() (RawInstruction, error) {
+	return RawInstruction{
+		Op: opClsJump | opJumpAlways,
+		K:  a.Skip,
+	}, nil
+}
+
+// String returns the instruction in assembler notation.
+func (a Jump) String() string {
+	return fmt.Sprintf("ja %d", a.Skip)
+}
+
+// JumpIf skips the following Skip instructions in the program if A
+// <Cond> Val is true.
+type JumpIf struct {
+	Cond      JumpTest
+	Val       uint32
+	SkipTrue  uint8
+	SkipFalse uint8
+}
+
+// Assemble implements the Instruction Assemble method.
+func (a JumpIf) Assemble() (RawInstruction, error) {
+	var (
+		cond uint16
+		flip bool
+	)
+	switch a.Cond {
+	case JumpEqual:
+		cond = opJumpEqual
+	case JumpNotEqual:
+		cond, flip = opJumpEqual, true
+	case JumpGreaterThan:
+		cond = opJumpGT
+	case JumpLessThan:
+		cond, flip = opJumpGE, true
+	case JumpGreaterOrEqual:
+		cond = opJumpGE
+	case JumpLessOrEqual:
+		cond, flip = opJumpGT, true
+	case JumpBitsSet:
+		cond = opJumpSet
+	case JumpBitsNotSet:
+		cond, flip = opJumpSet, true
+	default:
+		return RawInstruction{}, fmt.Errorf("unknown JumpTest %v", a.Cond)
+	}
+	jt, jf := a.SkipTrue, a.SkipFalse
+	if flip {
+		jt, jf = jf, jt
+	}
+	return RawInstruction{
+		Op: opClsJump | cond,
+		Jt: jt,
+		Jf: jf,
+		K:  a.Val,
+	}, nil
+}
+
+// String returns the instruction in assembler notation.
+func (a JumpIf) String() string {
+	switch a.Cond {
+	// K == A
+	case JumpEqual:
+		return conditionalJump(a, "jeq", "jneq")
+	// K != A
+	case JumpNotEqual:
+		return fmt.Sprintf("jneq #%d,%d", a.Val, a.SkipTrue)
+	// K > A
+	case JumpGreaterThan:
+		return conditionalJump(a, "jgt", "jle")
+	// K < A
+	case JumpLessThan:
+		return fmt.Sprintf("jlt #%d,%d", a.Val, a.SkipTrue)
+	// K >= A
+	case JumpGreaterOrEqual:
+		return conditionalJump(a, "jge", "jlt")
+	// K <= A
+	case JumpLessOrEqual:
+		return fmt.Sprintf("jle #%d,%d", a.Val, a.SkipTrue)
+	// K & A != 0
+	case JumpBitsSet:
+		if a.SkipFalse > 0 {
+			return fmt.Sprintf("jset #%d,%d,%d", a.Val, a.SkipTrue, a.SkipFalse)
+		}
+		return fmt.Sprintf("jset #%d,%d", a.Val, a.SkipTrue)
+	// K & A == 0, there is no assembler instruction for JumpBitNotSet, use JumpBitSet and invert skips
+	case JumpBitsNotSet:
+		return JumpIf{Cond: JumpBitsSet, SkipTrue: a.SkipFalse, SkipFalse: a.SkipTrue, Val: a.Val}.String()
+	default:
+		return fmt.Sprintf("unknown instruction: %#v", a)
+	}
+}
+
+func conditionalJump(inst JumpIf, positiveJump, negativeJump string) string {
+	if inst.SkipTrue > 0 {
+		if inst.SkipFalse > 0 {
+			return fmt.Sprintf("%s #%d,%d,%d", positiveJump, inst.Val, inst.SkipTrue, inst.SkipFalse)
+		}
+		return fmt.Sprintf("%s #%d,%d", positiveJump, inst.Val, inst.SkipTrue)
+	}
+	return fmt.Sprintf("%s #%d,%d", negativeJump, inst.Val, inst.SkipFalse)
+}
+
+// RetA exits the BPF program, returning the value of register A.
+type RetA struct{}
+
+// Assemble implements the Instruction Assemble method.
+func (a RetA) Assemble() (RawInstruction, error) {
+	return RawInstruction{
+		Op: opClsReturn | opRetSrcA,
+	}, nil
+}
+
+// String returns the instruction in assembler notation.
+func (a RetA) String() string {
+	return fmt.Sprintf("ret a")
+}
+
+// RetConstant exits the BPF program, returning a constant value.
+type RetConstant struct {
+	Val uint32
+}
+
+// Assemble implements the Instruction Assemble method.
+func (a RetConstant) Assemble() (RawInstruction, error) {
+	return RawInstruction{
+		Op: opClsReturn | opRetSrcConstant,
+		K:  a.Val,
+	}, nil
+}
+
+// String returns the instruction in assembler notation.
+func (a RetConstant) String() string {
+	return fmt.Sprintf("ret #%d", a.Val)
+}
+
+// TXA copies the value of register X to register A.
+type TXA struct{}
+
+// Assemble implements the Instruction Assemble method.
+func (a TXA) Assemble() (RawInstruction, error) {
+	return RawInstruction{
+		Op: opClsMisc | opMiscTXA,
+	}, nil
+}
+
+// String returns the instruction in assembler notation.
+func (a TXA) String() string {
+	return fmt.Sprintf("txa")
+}
+
+// TAX copies the value of register A to register X.
+type TAX struct{}
+
+// Assemble implements the Instruction Assemble method.
+func (a TAX) Assemble() (RawInstruction, error) {
+	return RawInstruction{
+		Op: opClsMisc | opMiscTAX,
+	}, nil
+}
+
+// String returns the instruction in assembler notation.
+func (a TAX) String() string {
+	return fmt.Sprintf("tax")
+}
+
+func assembleLoad(dst Register, loadSize int, mode uint16, k uint32) (RawInstruction, error) {
+	var (
+		cls uint16
+		sz  uint16
+	)
+	switch dst {
+	case RegA:
+		cls = opClsLoadA
+	case RegX:
+		cls = opClsLoadX
+	default:
+		return RawInstruction{}, fmt.Errorf("invalid target register %v", dst)
+	}
+	switch loadSize {
+	case 1:
+		sz = opLoadWidth1
+	case 2:
+		sz = opLoadWidth2
+	case 4:
+		sz = opLoadWidth4
+	default:
+		return RawInstruction{}, fmt.Errorf("invalid load byte length %d", sz)
+	}
+	return RawInstruction{
+		Op: cls | sz | mode,
+		K:  k,
+	}, nil
+}

vendor/golang.org/x/net/bpf/instructions_test.go

@@ -0,0 +1,525 @@
+// Copyright 2016 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 bpf
+
+import (
+	"fmt"
+	"io/ioutil"
+	"reflect"
+	"strconv"
+	"strings"
+	"testing"
+)
+
+// This is a direct translation of the program in
+// testdata/all_instructions.txt.
+var allInstructions = []Instruction{
+	LoadConstant{Dst: RegA, Val: 42},
+	LoadConstant{Dst: RegX, Val: 42},
+
+	LoadScratch{Dst: RegA, N: 3},
+	LoadScratch{Dst: RegX, N: 3},
+
+	LoadAbsolute{Off: 42, Size: 1},
+	LoadAbsolute{Off: 42, Size: 2},
+	LoadAbsolute{Off: 42, Size: 4},
+
+	LoadIndirect{Off: 42, Size: 1},
+	LoadIndirect{Off: 42, Size: 2},
+	LoadIndirect{Off: 42, Size: 4},
+
+	LoadMemShift{Off: 42},
+
+	LoadExtension{Num: ExtLen},
+	LoadExtension{Num: ExtProto},
+	LoadExtension{Num: ExtType},
+	LoadExtension{Num: ExtRand},
+
+	StoreScratch{Src: RegA, N: 3},
+	StoreScratch{Src: RegX, N: 3},
+
+	ALUOpConstant{Op: ALUOpAdd, Val: 42},
+	ALUOpConstant{Op: ALUOpSub, Val: 42},
+	ALUOpConstant{Op: ALUOpMul, Val: 42},
+	ALUOpConstant{Op: ALUOpDiv, Val: 42},
+	ALUOpConstant{Op: ALUOpOr, Val: 42},
+	ALUOpConstant{Op: ALUOpAnd, Val: 42},
+	ALUOpConstant{Op: ALUOpShiftLeft, Val: 42},
+	ALUOpConstant{Op: ALUOpShiftRight, Val: 42},
+	ALUOpConstant{Op: ALUOpMod, Val: 42},
+	ALUOpConstant{Op: ALUOpXor, Val: 42},
+
+	ALUOpX{Op: ALUOpAdd},
+	ALUOpX{Op: ALUOpSub},
+	ALUOpX{Op: ALUOpMul},
+	ALUOpX{Op: ALUOpDiv},
+	ALUOpX{Op: ALUOpOr},
+	ALUOpX{Op: ALUOpAnd},
+	ALUOpX{Op: ALUOpShiftLeft},
+	ALUOpX{Op: ALUOpShiftRight},
+	ALUOpX{Op: ALUOpMod},
+	ALUOpX{Op: ALUOpXor},
+
+	NegateA{},
+
+	Jump{Skip: 10},
+	JumpIf{Cond: JumpEqual, Val: 42, SkipTrue: 8, SkipFalse: 9},
+	JumpIf{Cond: JumpNotEqual, Val: 42, SkipTrue: 8},
+	JumpIf{Cond: JumpLessThan, Val: 42, SkipTrue: 7},
+	JumpIf{Cond: JumpLessOrEqual, Val: 42, SkipTrue: 6},
+	JumpIf{Cond: JumpGreaterThan, Val: 42, SkipTrue: 4, SkipFalse: 5},
+	JumpIf{Cond: JumpGreaterOrEqual, Val: 42, SkipTrue: 3, SkipFalse: 4},
+	JumpIf{Cond: JumpBitsSet, Val: 42, SkipTrue: 2, SkipFalse: 3},
+
+	TAX{},
+	TXA{},
+
+	RetA{},
+	RetConstant{Val: 42},
+}
+var allInstructionsExpected = "testdata/all_instructions.bpf"
+
+// Check that we produce the same output as the canonical bpf_asm
+// linux kernel tool.
+func TestInterop(t *testing.T) {
+	out, err := Assemble(allInstructions)
+	if err != nil {
+		t.Fatalf("assembly of allInstructions program failed: %s", err)
+	}
+	t.Logf("Assembled program is %d instructions long", len(out))
+
+	bs, err := ioutil.ReadFile(allInstructionsExpected)
+	if err != nil {
+		t.Fatalf("reading %s: %s", allInstructionsExpected, err)
+	}
+	// First statement is the number of statements, last statement is
+	// empty. We just ignore both and rely on slice length.
+	stmts := strings.Split(string(bs), ",")
+	if len(stmts)-2 != len(out) {
+		t.Fatalf("test program lengths don't match: %s has %d, Go implementation has %d", allInstructionsExpected, len(stmts)-2, len(allInstructions))
+	}
+
+	for i, stmt := range stmts[1 : len(stmts)-2] {
+		nums := strings.Split(stmt, " ")
+		if len(nums) != 4 {
+			t.Fatalf("malformed instruction %d in %s: %s", i+1, allInstructionsExpected, stmt)
+		}
+
+		actual := out[i]
+
+		op, err := strconv.ParseUint(nums[0], 10, 16)
+		if err != nil {
+			t.Fatalf("malformed opcode %s in instruction %d of %s", nums[0], i+1, allInstructionsExpected)
+		}
+		if actual.Op != uint16(op) {
+			t.Errorf("opcode mismatch on instruction %d (%#v): got 0x%02x, want 0x%02x", i+1, allInstructions[i], actual.Op, op)
+		}
+
+		jt, err := strconv.ParseUint(nums[1], 10, 8)
+		if err != nil {
+			t.Fatalf("malformed jt offset %s in instruction %d of %s", nums[1], i+1, allInstructionsExpected)
+		}
+		if actual.Jt != uint8(jt) {
+			t.Errorf("jt mismatch on instruction %d (%#v): got %d, want %d", i+1, allInstructions[i], actual.Jt, jt)
+		}
+
+		jf, err := strconv.ParseUint(nums[2], 10, 8)
+		if err != nil {
+			t.Fatalf("malformed jf offset %s in instruction %d of %s", nums[2], i+1, allInstructionsExpected)
+		}
+		if actual.Jf != uint8(jf) {
+			t.Errorf("jf mismatch on instruction %d (%#v): got %d, want %d", i+1, allInstructions[i], actual.Jf, jf)
+		}
+
+		k, err := strconv.ParseUint(nums[3], 10, 32)
+		if err != nil {
+			t.Fatalf("malformed constant %s in instruction %d of %s", nums[3], i+1, allInstructionsExpected)
+		}
+		if actual.K != uint32(k) {
+			t.Errorf("constant mismatch on instruction %d (%#v): got %d, want %d", i+1, allInstructions[i], actual.K, k)
+		}
+	}
+}
+
+// Check that assembly and disassembly match each other.
+func TestAsmDisasm(t *testing.T) {
+	prog1, err := Assemble(allInstructions)
+	if err != nil {
+		t.Fatalf("assembly of allInstructions program failed: %s", err)
+	}
+	t.Logf("Assembled program is %d instructions long", len(prog1))
+
+	got, allDecoded := Disassemble(prog1)
+	if !allDecoded {
+		t.Errorf("Disassemble(Assemble(allInstructions)) produced unrecognized instructions:")
+		for i, inst := range got {
+			if r, ok := inst.(RawInstruction); ok {
+				t.Logf("  insn %d, %#v --> %#v", i+1, allInstructions[i], r)
+			}
+		}
+	}
+
+	if len(allInstructions) != len(got) {
+		t.Fatalf("disassembly changed program size: %d insns before, %d insns after", len(allInstructions), len(got))
+	}
+	if !reflect.DeepEqual(allInstructions, got) {
+		t.Errorf("program mutated by disassembly:")
+		for i := range got {
+			if !reflect.DeepEqual(allInstructions[i], got[i]) {
+				t.Logf("  insn %d, s: %#v, p1: %#v, got: %#v", i+1, allInstructions[i], prog1[i], got[i])
+			}
+		}
+	}
+}
+
+type InvalidInstruction struct{}
+
+func (a InvalidInstruction) Assemble() (RawInstruction, error) {
+	return RawInstruction{}, fmt.Errorf("Invalid Instruction")
+}
+
+func (a InvalidInstruction) String() string {
+	return fmt.Sprintf("unknown instruction: %#v", a)
+}
+
+func TestString(t *testing.T) {
+	testCases := []struct {
+		instruction Instruction
+		assembler   string
+	}{
+		{
+			instruction: LoadConstant{Dst: RegA, Val: 42},
+			assembler:   "ld #42",
+		},
+		{
+			instruction: LoadConstant{Dst: RegX, Val: 42},
+			assembler:   "ldx #42",
+		},
+		{
+			instruction: LoadConstant{Dst: 0xffff, Val: 42},
+			assembler:   "unknown instruction: bpf.LoadConstant{Dst:0xffff, Val:0x2a}",
+		},
+		{
+			instruction: LoadScratch{Dst: RegA, N: 3},
+			assembler:   "ld M[3]",
+		},
+		{
+			instruction: LoadScratch{Dst: RegX, N: 3},
+			assembler:   "ldx M[3]",
+		},
+		{
+			instruction: LoadScratch{Dst: 0xffff, N: 3},
+			assembler:   "unknown instruction: bpf.LoadScratch{Dst:0xffff, N:3}",
+		},
+		{
+			instruction: LoadAbsolute{Off: 42, Size: 1},
+			assembler:   "ldb [42]",
+		},
+		{
+			instruction: LoadAbsolute{Off: 42, Size: 2},
+			assembler:   "ldh [42]",
+		},
+		{
+			instruction: LoadAbsolute{Off: 42, Size: 4},
+			assembler:   "ld [42]",
+		},
+		{
+			instruction: LoadAbsolute{Off: 42, Size: -1},
+			assembler:   "unknown instruction: bpf.LoadAbsolute{Off:0x2a, Size:-1}",
+		},
+		{
+			instruction: LoadIndirect{Off: 42, Size: 1},
+			assembler:   "ldb [x + 42]",
+		},
+		{
+			instruction: LoadIndirect{Off: 42, Size: 2},
+			assembler:   "ldh [x + 42]",
+		},
+		{
+			instruction: LoadIndirect{Off: 42, Size: 4},
+			assembler:   "ld [x + 42]",
+		},
+		{
+			instruction: LoadIndirect{Off: 42, Size: -1},
+			assembler:   "unknown instruction: bpf.LoadIndirect{Off:0x2a, Size:-1}",
+		},
+		{
+			instruction: LoadMemShift{Off: 42},
+			assembler:   "ldx 4*([42]&0xf)",
+		},
+		{
+			instruction: LoadExtension{Num: ExtLen},
+			assembler:   "ld #len",
+		},
+		{
+			instruction: LoadExtension{Num: ExtProto},
+			assembler:   "ld #proto",
+		},
+		{
+			instruction: LoadExtension{Num: ExtType},
+			assembler:   "ld #type",
+		},
+		{
+			instruction: LoadExtension{Num: ExtPayloadOffset},
+			assembler:   "ld #poff",
+		},
+		{
+			instruction: LoadExtension{Num: ExtInterfaceIndex},
+			assembler:   "ld #ifidx",
+		},
+		{
+			instruction: LoadExtension{Num: ExtNetlinkAttr},
+			assembler:   "ld #nla",
+		},
+		{
+			instruction: LoadExtension{Num: ExtNetlinkAttrNested},
+			assembler:   "ld #nlan",
+		},
+		{
+			instruction: LoadExtension{Num: ExtMark},
+			assembler:   "ld #mark",
+		},
+		{
+			instruction: LoadExtension{Num: ExtQueue},
+			assembler:   "ld #queue",
+		},
+		{
+			instruction: LoadExtension{Num: ExtLinkLayerType},
+			assembler:   "ld #hatype",
+		},
+		{
+			instruction: LoadExtension{Num: ExtRXHash},
+			assembler:   "ld #rxhash",
+		},
+		{
+			instruction: LoadExtension{Num: ExtCPUID},
+			assembler:   "ld #cpu",
+		},
+		{
+			instruction: LoadExtension{Num: ExtVLANTag},
+			assembler:   "ld #vlan_tci",
+		},
+		{
+			instruction: LoadExtension{Num: ExtVLANTagPresent},
+			assembler:   "ld #vlan_avail",
+		},
+		{
+			instruction: LoadExtension{Num: ExtVLANProto},
+			assembler:   "ld #vlan_tpid",
+		},
+		{
+			instruction: LoadExtension{Num: ExtRand},
+			assembler:   "ld #rand",
+		},
+		{
+			instruction: LoadAbsolute{Off: 0xfffff038, Size: 4},
+			assembler:   "ld #rand",
+		},
+		{
+			instruction: LoadExtension{Num: 0xfff},
+			assembler:   "unknown instruction: bpf.LoadExtension{Num:4095}",
+		},
+		{
+			instruction: StoreScratch{Src: RegA, N: 3},
+			assembler:   "st M[3]",
+		},
+		{
+			instruction: StoreScratch{Src: RegX, N: 3},
+			assembler:   "stx M[3]",
+		},
+		{
+			instruction: StoreScratch{Src: 0xffff, N: 3},
+			assembler:   "unknown instruction: bpf.StoreScratch{Src:0xffff, N:3}",
+		},
+		{
+			instruction: ALUOpConstant{Op: ALUOpAdd, Val: 42},
+			assembler:   "add #42",
+		},
+		{
+			instruction: ALUOpConstant{Op: ALUOpSub, Val: 42},
+			assembler:   "sub #42",
+		},
+		{
+			instruction: ALUOpConstant{Op: ALUOpMul, Val: 42},
+			assembler:   "mul #42",
+		},
+		{
+			instruction: ALUOpConstant{Op: ALUOpDiv, Val: 42},
+			assembler:   "div #42",
+		},
+		{
+			instruction: ALUOpConstant{Op: ALUOpOr, Val: 42},
+			assembler:   "or #42",
+		},
+		{
+			instruction: ALUOpConstant{Op: ALUOpAnd, Val: 42},
+			assembler:   "and #42",
+		},
+		{
+			instruction: ALUOpConstant{Op: ALUOpShiftLeft, Val: 42},
+			assembler:   "lsh #42",
+		},
+		{
+			instruction: ALUOpConstant{Op: ALUOpShiftRight, Val: 42},
+			assembler:   "rsh #42",
+		},
+		{
+			instruction: ALUOpConstant{Op: ALUOpMod, Val: 42},
+			assembler:   "mod #42",
+		},
+		{
+			instruction: ALUOpConstant{Op: ALUOpXor, Val: 42},
+			assembler:   "xor #42",
+		},
+		{
+			instruction: ALUOpConstant{Op: 0xffff, Val: 42},
+			assembler:   "unknown instruction: bpf.ALUOpConstant{Op:0xffff, Val:0x2a}",
+		},
+		{
+			instruction: ALUOpX{Op: ALUOpAdd},
+			assembler:   "add x",
+		},
+		{
+			instruction: ALUOpX{Op: ALUOpSub},
+			assembler:   "sub x",
+		},
+		{
+			instruction: ALUOpX{Op: ALUOpMul},
+			assembler:   "mul x",
+		},
+		{
+			instruction: ALUOpX{Op: ALUOpDiv},
+			assembler:   "div x",
+		},
+		{
+			instruction: ALUOpX{Op: ALUOpOr},
+			assembler:   "or x",
+		},
+		{
+			instruction: ALUOpX{Op: ALUOpAnd},
+			assembler:   "and x",
+		},
+		{
+			instruction: ALUOpX{Op: ALUOpShiftLeft},
+			assembler:   "lsh x",
+		},
+		{
+			instruction: ALUOpX{Op: ALUOpShiftRight},
+			assembler:   "rsh x",
+		},
+		{
+			instruction: ALUOpX{Op: ALUOpMod},
+			assembler:   "mod x",
+		},
+		{
+			instruction: ALUOpX{Op: ALUOpXor},
+			assembler:   "xor x",
+		},
+		{
+			instruction: ALUOpX{Op: 0xffff},
+			assembler:   "unknown instruction: bpf.ALUOpX{Op:0xffff}",
+		},
+		{
+			instruction: NegateA{},
+			assembler:   "neg",
+		},
+		{
+			instruction: Jump{Skip: 10},
+			assembler:   "ja 10",
+		},
+		{
+			instruction: JumpIf{Cond: JumpEqual, Val: 42, SkipTrue: 8, SkipFalse: 9},
+			assembler:   "jeq #42,8,9",
+		},
+		{
+			instruction: JumpIf{Cond: JumpEqual, Val: 42, SkipTrue: 8},
+			assembler:   "jeq #42,8",
+		},
+		{
+			instruction: JumpIf{Cond: JumpEqual, Val: 42, SkipFalse: 8},
+			assembler:   "jneq #42,8",
+		},
+		{
+			instruction: JumpIf{Cond: JumpNotEqual, Val: 42, SkipTrue: 8},
+			assembler:   "jneq #42,8",
+		},
+		{
+			instruction: JumpIf{Cond: JumpLessThan, Val: 42, SkipTrue: 7},
+			assembler:   "jlt #42,7",
+		},
+		{
+			instruction: JumpIf{Cond: JumpLessOrEqual, Val: 42, SkipTrue: 6},
+			assembler:   "jle #42,6",
+		},
+		{
+			instruction: JumpIf{Cond: JumpGreaterThan, Val: 42, SkipTrue: 4, SkipFalse: 5},
+			assembler:   "jgt #42,4,5",
+		},
+		{
+			instruction: JumpIf{Cond: JumpGreaterThan, Val: 42, SkipTrue: 4},
+			assembler:   "jgt #42,4",
+		},
+		{
+			instruction: JumpIf{Cond: JumpGreaterOrEqual, Val: 42, SkipTrue: 3, SkipFalse: 4},
+			assembler:   "jge #42,3,4",
+		},
+		{
+			instruction: JumpIf{Cond: JumpGreaterOrEqual, Val: 42, SkipTrue: 3},
+			assembler:   "jge #42,3",
+		},
+		{
+			instruction: JumpIf{Cond: JumpBitsSet, Val: 42, SkipTrue: 2, SkipFalse: 3},
+			assembler:   "jset #42,2,3",
+		},
+		{
+			instruction: JumpIf{Cond: JumpBitsSet, Val: 42, SkipTrue: 2},
+			assembler:   "jset #42,2",
+		},
+		{
+			instruction: JumpIf{Cond: JumpBitsNotSet, Val: 42, SkipTrue: 2, SkipFalse: 3},
+			assembler:   "jset #42,3,2",
+		},
+		{
+			instruction: JumpIf{Cond: JumpBitsNotSet, Val: 42, SkipTrue: 2},
+			assembler:   "jset #42,0,2",
+		},
+		{
+			instruction: JumpIf{Cond: 0xffff, Val: 42, SkipTrue: 1, SkipFalse: 2},
+			assembler:   "unknown instruction: bpf.JumpIf{Cond:0xffff, Val:0x2a, SkipTrue:0x1, SkipFalse:0x2}",
+		},
+		{
+			instruction: TAX{},
+			assembler:   "tax",
+		},
+		{
+			instruction: TXA{},
+			assembler:   "txa",
+		},
+		{
+			instruction: RetA{},
+			assembler:   "ret a",
+		},
+		{
+			instruction: RetConstant{Val: 42},
+			assembler:   "ret #42",
+		},
+		// Invalid instruction
+		{
+			instruction: InvalidInstruction{},
+			assembler:   "unknown instruction: bpf.InvalidInstruction{}",
+		},
+	}
+
+	for _, testCase := range testCases {
+		if input, ok := testCase.instruction.(fmt.Stringer); ok {
+			got := input.String()
+			if got != testCase.assembler {
+				t.Errorf("String did not return expected assembler notation, expected: %s, got: %s", testCase.assembler, got)
+			}
+		} else {
+			t.Errorf("Instruction %#v is not a fmt.Stringer", testCase.instruction)
+		}
+	}
+}

vendor/golang.org/x/net/bpf/setter.go

@@ -0,0 +1,10 @@
+// Copyright 2017 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 bpf
+
+// A Setter is a type which can attach a compiled BPF filter to itself.
+type Setter interface {
+	SetBPF(filter []RawInstruction) error
+}

vendor/golang.org/x/net/bpf/testdata/all_instructions.bpf

@@ -0,0 +1 @@
+50,0 0 0 42,1 0 0 42,96 0 0 3,97 0 0 3,48 0 0 42,40 0 0 42,32 0 0 42,80 0 0 42,72 0 0 42,64 0 0 42,177 0 0 42,128 0 0 0,32 0 0 4294963200,32 0 0 4294963204,32 0 0 4294963256,2 0 0 3,3 0 0 3,4 0 0 42,20 0 0 42,36 0 0 42,52 0 0 42,68 0 0 42,84 0 0 42,100 0 0 42,116 0 0 42,148 0 0 42,164 0 0 42,12 0 0 0,28 0 0 0,44 0 0 0,60 0 0 0,76 0 0 0,92 0 0 0,108 0 0 0,124 0 0 0,156 0 0 0,172 0 0 0,132 0 0 0,5 0 0 10,21 8 9 42,21 0 8 42,53 0 7 42,37 0 6 42,37 4 5 42,53 3 4 42,69 2 3 42,7 0 0 0,135 0 0 0,22 0 0 0,6 0 0 0,

vendor/golang.org/x/net/bpf/testdata/all_instructions.txt

@@ -0,0 +1,79 @@
+# This filter is compiled to all_instructions.bpf by the `bpf_asm`
+# tool, which can be found in the linux kernel source tree under
+# tools/net.
+
+# Load immediate
+ld #42
+ldx #42
+
+# Load scratch
+ld M[3]
+ldx M[3]
+
+# Load absolute
+ldb [42]
+ldh [42]
+ld [42]
+
+# Load indirect
+ldb [x + 42]
+ldh [x + 42]
+ld [x + 42]
+
+# Load IPv4 header length
+ldx 4*([42]&0xf)
+
+# Run extension function
+ld #len
+ld #proto
+ld #type
+ld #rand
+
+# Store scratch
+st M[3]
+stx M[3]
+
+# A <op> constant
+add #42
+sub #42
+mul #42
+div #42
+or #42
+and #42
+lsh #42
+rsh #42
+mod #42
+xor #42
+
+# A <op> X
+add x
+sub x
+mul x
+div x
+or x
+and x
+lsh x
+rsh x
+mod x
+xor x
+
+# !A
+neg
+
+# Jumps
+ja end
+jeq #42,prev,end
+jne #42,end
+jlt #42,end
+jle #42,end
+jgt #42,prev,end
+jge #42,prev,end
+jset #42,prev,end
+
+# Register transfers
+tax
+txa
+
+# Returns
+prev: ret a
+end: ret #42

vendor/golang.org/x/net/bpf/vm.go

@@ -0,0 +1,140 @@
+// Copyright 2016 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 bpf
+
+import (
+	"errors"
+	"fmt"
+)
+
+// A VM is an emulated BPF virtual machine.
+type VM struct {
+	filter []Instruction
+}
+
+// NewVM returns a new VM using the input BPF program.
+func NewVM(filter []Instruction) (*VM, error) {
+	if len(filter) == 0 {
+		return nil, errors.New("one or more Instructions must be specified")
+	}
+
+	for i, ins := range filter {
+		check := len(filter) - (i + 1)
+		switch ins := ins.(type) {
+		// Check for out-of-bounds jumps in instructions
+		case Jump:
+			if check <= int(ins.Skip) {
+				return nil, fmt.Errorf("cannot jump %d instructions; jumping past program bounds", ins.Skip)
+			}
+		case JumpIf:
+			if check <= int(ins.SkipTrue) {
+				return nil, fmt.Errorf("cannot jump %d instructions in true case; jumping past program bounds", ins.SkipTrue)
+			}
+			if check <= int(ins.SkipFalse) {
+				return nil, fmt.Errorf("cannot jump %d instructions in false case; jumping past program bounds", ins.SkipFalse)
+			}
+		// Check for division or modulus by zero
+		case ALUOpConstant:
+			if ins.Val != 0 {
+				break
+			}
+
+			switch ins.Op {
+			case ALUOpDiv, ALUOpMod:
+				return nil, errors.New("cannot divide by zero using ALUOpConstant")
+			}
+		// Check for unknown extensions
+		case LoadExtension:
+			switch ins.Num {
+			case ExtLen:
+			default:
+				return nil, fmt.Errorf("extension %d not implemented", ins.Num)
+			}
+		}
+	}
+
+	// Make sure last instruction is a return instruction
+	switch filter[len(filter)-1].(type) {
+	case RetA, RetConstant:
+	default:
+		return nil, errors.New("BPF program must end with RetA or RetConstant")
+	}
+
+	// Though our VM works using disassembled instructions, we
+	// attempt to assemble the input filter anyway to ensure it is compatible
+	// with an operating system VM.
+	_, err := Assemble(filter)
+
+	return &VM{
+		filter: filter,
+	}, err
+}
+
+// Run runs the VM's BPF program against the input bytes.
+// Run returns the number of bytes accepted by the BPF program, and any errors
+// which occurred while processing the program.
+func (v *VM) Run(in []byte) (int, error) {
+	var (
+		// Registers of the virtual machine
+		regA       uint32
+		regX       uint32
+		regScratch [16]uint32
+
+		// OK is true if the program should continue processing the next
+		// instruction, or false if not, causing the loop to break
+		ok = true
+	)
+
+	// TODO(mdlayher): implement:
+	// - NegateA:
+	//   - would require a change from uint32 registers to int32
+	//     registers
+
+	// TODO(mdlayher): add interop tests that check signedness of ALU
+	// operations against kernel implementation, and make sure Go
+	// implementation matches behavior
+
+	for i := 0; i < len(v.filter) && ok; i++ {
+		ins := v.filter[i]
+
+		switch ins := ins.(type) {
+		case ALUOpConstant:
+			regA = aluOpConstant(ins, regA)
+		case ALUOpX:
+			regA, ok = aluOpX(ins, regA, regX)
+		case Jump:
+			i += int(ins.Skip)
+		case JumpIf:
+			jump := jumpIf(ins, regA)
+			i += jump
+		case LoadAbsolute:
+			regA, ok = loadAbsolute(ins, in)
+		case LoadConstant:
+			regA, regX = loadConstant(ins, regA, regX)
+		case LoadExtension:
+			regA = loadExtension(ins, in)
+		case LoadIndirect:
+			regA, ok = loadIndirect(ins, in, regX)
+		case LoadMemShift:
+			regX, ok = loadMemShift(ins, in)
+		case LoadScratch:
+			regA, regX = loadScratch(ins, regScratch, regA, regX)
+		case RetA:
+			return int(regA), nil
+		case RetConstant:
+			return int(ins.Val), nil
+		case StoreScratch:
+			regScratch = storeScratch(ins, regScratch, regA, regX)
+		case TAX:
+			regX = regA
+		case TXA:
+			regA = regX
+		default:
+			return 0, fmt.Errorf("unknown Instruction at index %d: %T", i, ins)
+		}
+	}
+
+	return 0, nil
+}

vendor/golang.org/x/net/bpf/vm_aluop_test.go

@@ -0,0 +1,512 @@
+// Copyright 2016 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 bpf_test
+
+import (
+	"testing"
+
+	"golang.org/x/net/bpf"
+)
+
+func TestVMALUOpAdd(t *testing.T) {
+	vm, done, err := testVM(t, []bpf.Instruction{
+		bpf.LoadAbsolute{
+			Off:  8,
+			Size: 1,
+		},
+		bpf.ALUOpConstant{
+			Op:  bpf.ALUOpAdd,
+			Val: 3,
+		},
+		bpf.RetA{},
+	})
+	if err != nil {
+		t.Fatalf("failed to load BPF program: %v", err)
+	}
+	defer done()
+
+	out, err := vm.Run([]byte{
+		0xff, 0xff, 0xff, 0xff,
+		0xff, 0xff, 0xff, 0xff,
+		8, 2, 3,
+	})
+	if err != nil {
+		t.Fatalf("unexpected error while running program: %v", err)
+	}
+	if want, got := 3, out; want != got {
+		t.Fatalf("unexpected number of output bytes:\n- want: %d\n-  got: %d",
+			want, got)
+	}
+}
+
+func TestVMALUOpSub(t *testing.T) {
+	vm, done, err := testVM(t, []bpf.Instruction{
+		bpf.LoadAbsolute{
+			Off:  8,
+			Size: 1,
+		},
+		bpf.TAX{},
+		bpf.ALUOpX{
+			Op: bpf.ALUOpSub,
+		},
+		bpf.RetA{},
+	})
+	if err != nil {
+		t.Fatalf("failed to load BPF program: %v", err)
+	}
+	defer done()
+
+	out, err := vm.Run([]byte{
+		0xff, 0xff, 0xff, 0xff,
+		0xff, 0xff, 0xff, 0xff,
+		1, 2, 3,
+	})
+	if err != nil {
+		t.Fatalf("unexpected error while running program: %v", err)
+	}
+	if want, got := 0, out; want != got {
+		t.Fatalf("unexpected number of output bytes:\n- want: %d\n-  got: %d",
+			want, got)
+	}
+}
+
+func TestVMALUOpMul(t *testing.T) {
+	vm, done, err := testVM(t, []bpf.Instruction{
+		bpf.LoadAbsolute{
+			Off:  8,
+			Size: 1,
+		},
+		bpf.ALUOpConstant{
+			Op:  bpf.ALUOpMul,
+			Val: 2,
+		},
+		bpf.RetA{},
+	})
+	if err != nil {
+		t.Fatalf("failed to load BPF program: %v", err)
+	}
+	defer done()
+
+	out, err := vm.Run([]byte{
+		0xff, 0xff, 0xff, 0xff,
+		0xff, 0xff, 0xff, 0xff,
+		6, 2, 3, 4,
+	})
+	if err != nil {
+		t.Fatalf("unexpected error while running program: %v", err)
+	}
+	if want, got := 4, out; want != got {
+		t.Fatalf("unexpected number of output bytes:\n- want: %d\n-  got: %d",
+			want, got)
+	}
+}
+
+func TestVMALUOpDiv(t *testing.T) {
+	vm, done, err := testVM(t, []bpf.Instruction{
+		bpf.LoadAbsolute{
+			Off:  8,
+			Size: 1,
+		},
+		bpf.ALUOpConstant{
+			Op:  bpf.ALUOpDiv,
+			Val: 2,
+		},
+		bpf.RetA{},
+	})
+	if err != nil {
+		t.Fatalf("failed to load BPF program: %v", err)
+	}
+	defer done()
+
+	out, err := vm.Run([]byte{
+		0xff, 0xff, 0xff, 0xff,
+		0xff, 0xff, 0xff, 0xff,
+		20, 2, 3, 4,
+	})
+	if err != nil {
+		t.Fatalf("unexpected error while running program: %v", err)
+	}
+	if want, got := 2, out; want != got {
+		t.Fatalf("unexpected number of output bytes:\n- want: %d\n-  got: %d",
+			want, got)
+	}
+}
+
+func TestVMALUOpDivByZeroALUOpConstant(t *testing.T) {
+	_, _, err := testVM(t, []bpf.Instruction{
+		bpf.ALUOpConstant{
+			Op:  bpf.ALUOpDiv,
+			Val: 0,
+		},
+		bpf.RetA{},
+	})
+	if errStr(err) != "cannot divide by zero using ALUOpConstant" {
+		t.Fatalf("unexpected error: %v", err)
+	}
+}
+
+func TestVMALUOpDivByZeroALUOpX(t *testing.T) {
+	vm, done, err := testVM(t, []bpf.Instruction{
+		// Load byte 0 into X
+		bpf.LoadAbsolute{
+			Off:  8,
+			Size: 1,
+		},
+		bpf.TAX{},
+		// Load byte 1 into A
+		bpf.LoadAbsolute{
+			Off:  9,
+			Size: 1,
+		},
+		// Attempt to perform 1/0
+		bpf.ALUOpX{
+			Op: bpf.ALUOpDiv,
+		},
+		// Return 4 bytes if program does not terminate
+		bpf.LoadConstant{
+			Val: 12,
+		},
+		bpf.RetA{},
+	})
+	if err != nil {
+		t.Fatalf("failed to load BPF program: %v", err)
+	}
+	defer done()
+
+	out, err := vm.Run([]byte{
+		0xff, 0xff, 0xff, 0xff,
+		0xff, 0xff, 0xff, 0xff,
+		0, 1, 3, 4,
+	})
+	if err != nil {
+		t.Fatalf("unexpected error while running program: %v", err)
+	}
+	if want, got := 0, out; want != got {
+		t.Fatalf("unexpected number of output bytes:\n- want: %d\n-  got: %d",
+			want, got)
+	}
+}
+
+func TestVMALUOpOr(t *testing.T) {
+	vm, done, err := testVM(t, []bpf.Instruction{
+		bpf.LoadAbsolute{
+			Off:  8,
+			Size: 2,
+		},
+		bpf.ALUOpConstant{
+			Op:  bpf.ALUOpOr,
+			Val: 0x01,
+		},
+		bpf.RetA{},
+	})
+	if err != nil {
+		t.Fatalf("failed to load BPF program: %v", err)
+	}
+	defer done()
+
+	out, err := vm.Run([]byte{
+		0xff, 0xff, 0xff, 0xff,
+		0xff, 0xff, 0xff, 0xff,
+		0x00, 0x10, 0x03, 0x04,
+		0x05, 0x06, 0x07, 0x08,
+		0x09, 0xff,
+	})
+	if err != nil {
+		t.Fatalf("unexpected error while running program: %v", err)
+	}
+	if want, got := 9, out; want != got {
+		t.Fatalf("unexpected number of output bytes:\n- want: %d\n-  got: %d",
+			want, got)
+	}
+}
+
+func TestVMALUOpAnd(t *testing.T) {
+	vm, done, err := testVM(t, []bpf.Instruction{
+		bpf.LoadAbsolute{
+			Off:  8,
+			Size: 2,
+		},
+		bpf.ALUOpConstant{
+			Op:  bpf.ALUOpAnd,
+			Val: 0x0019,
+		},
+		bpf.RetA{},
+	})
+	if err != nil {
+		t.Fatalf("failed to load BPF program: %v", err)
+	}
+	defer done()
+
+	out, err := vm.Run([]byte{
+		0xff, 0xff, 0xff, 0xff,
+		0xff, 0xff, 0xff, 0xff,
+		0xaa, 0x09,
+	})
+	if err != nil {
+		t.Fatalf("unexpected error while running program: %v", err)
+	}
+	if want, got := 1, out; want != got {
+		t.Fatalf("unexpected number of output bytes:\n- want: %d\n-  got: %d",
+			want, got)
+	}
+}
+
+func TestVMALUOpShiftLeft(t *testing.T) {
+	vm, done, err := testVM(t, []bpf.Instruction{
+		bpf.LoadAbsolute{
+			Off:  8,
+			Size: 1,
+		},
+		bpf.ALUOpConstant{
+			Op:  bpf.ALUOpShiftLeft,
+			Val: 0x01,
+		},
+		bpf.JumpIf{
+			Cond:     bpf.JumpEqual,
+			Val:      0x02,
+			SkipTrue: 1,
+		},
+		bpf.RetConstant{
+			Val: 0,
+		},
+		bpf.RetConstant{
+			Val: 9,
+		},
+	})
+	if err != nil {
+		t.Fatalf("failed to load BPF program: %v", err)
+	}
+	defer done()
+
+	out, err := vm.Run([]byte{
+		0xff, 0xff, 0xff, 0xff,
+		0xff, 0xff, 0xff, 0xff,
+		0x01, 0xaa,
+	})
+	if err != nil {
+		t.Fatalf("unexpected error while running program: %v", err)
+	}
+	if want, got := 1, out; want != got {
+		t.Fatalf("unexpected number of output bytes:\n- want: %d\n-  got: %d",
+			want, got)
+	}
+}
+
+func TestVMALUOpShiftRight(t *testing.T) {
+	vm, done, err := testVM(t, []bpf.Instruction{
+		bpf.LoadAbsolute{
+			Off:  8,
+			Size: 1,
+		},
+		bpf.ALUOpConstant{
+			Op:  bpf.ALUOpShiftRight,
+			Val: 0x01,
+		},
+		bpf.JumpIf{
+			Cond:     bpf.JumpEqual,
+			Val:      0x04,
+			SkipTrue: 1,
+		},
+		bpf.RetConstant{
+			Val: 0,
+		},
+		bpf.RetConstant{
+			Val: 9,
+		},
+	})
+	if err != nil {
+		t.Fatalf("failed to load BPF program: %v", err)
+	}
+	defer done()
+
+	out, err := vm.Run([]byte{
+		0xff, 0xff, 0xff, 0xff,
+		0xff, 0xff, 0xff, 0xff,
+		0x08, 0xff, 0xff,
+	})
+	if err != nil {
+		t.Fatalf("unexpected error while running program: %v", err)
+	}
+	if want, got := 1, out; want != got {
+		t.Fatalf("unexpected number of output bytes:\n- want: %d\n-  got: %d",
+			want, got)
+	}
+}
+
+func TestVMALUOpMod(t *testing.T) {
+	vm, done, err := testVM(t, []bpf.Instruction{
+		bpf.LoadAbsolute{
+			Off:  8,
+			Size: 1,
+		},
+		bpf.ALUOpConstant{
+			Op:  bpf.ALUOpMod,
+			Val: 20,
+		},
+		bpf.RetA{},
+	})
+	if err != nil {
+		t.Fatalf("failed to load BPF program: %v", err)
+	}
+	defer done()
+
+	out, err := vm.Run([]byte{
+		0xff, 0xff, 0xff, 0xff,
+		0xff, 0xff, 0xff, 0xff,
+		30, 0, 0,
+	})
+	if err != nil {
+		t.Fatalf("unexpected error while running program: %v", err)
+	}
+	if want, got := 2, out; want != got {
+		t.Fatalf("unexpected number of output bytes:\n- want: %d\n-  got: %d",
+			want, got)
+	}
+}
+
+func TestVMALUOpModByZeroALUOpConstant(t *testing.T) {
+	_, _, err := testVM(t, []bpf.Instruction{
+		bpf.LoadAbsolute{
+			Off:  8,
+			Size: 1,
+		},
+		bpf.ALUOpConstant{
+			Op:  bpf.ALUOpMod,
+			Val: 0,
+		},
+		bpf.RetA{},
+	})
+	if errStr(err) != "cannot divide by zero using ALUOpConstant" {
+		t.Fatalf("unexpected error: %v", err)
+	}
+}
+
+func TestVMALUOpModByZeroALUOpX(t *testing.T) {
+	vm, done, err := testVM(t, []bpf.Instruction{
+		// Load byte 0 into X
+		bpf.LoadAbsolute{
+			Off:  8,
+			Size: 1,
+		},
+		bpf.TAX{},
+		// Load byte 1 into A
+		bpf.LoadAbsolute{
+			Off:  9,
+			Size: 1,
+		},
+		// Attempt to perform 1%0
+		bpf.ALUOpX{
+			Op: bpf.ALUOpMod,
+		},
+		// Return 4 bytes if program does not terminate
+		bpf.LoadConstant{
+			Val: 12,
+		},
+		bpf.RetA{},
+	})
+	if err != nil {
+		t.Fatalf("failed to load BPF program: %v", err)
+	}
+	defer done()
+
+	out, err := vm.Run([]byte{
+		0xff, 0xff, 0xff, 0xff,
+		0xff, 0xff, 0xff, 0xff,
+		0, 1, 3, 4,
+	})
+	if err != nil {
+		t.Fatalf("unexpected error while running program: %v", err)
+	}
+	if want, got := 0, out; want != got {
+		t.Fatalf("unexpected number of output bytes:\n- want: %d\n-  got: %d",
+			want, got)
+	}
+}
+
+func TestVMALUOpXor(t *testing.T) {
+	vm, done, err := testVM(t, []bpf.Instruction{
+		bpf.LoadAbsolute{
+			Off:  8,
+			Size: 1,
+		},
+		bpf.ALUOpConstant{
+			Op:  bpf.ALUOpXor,
+			Val: 0x0a,
+		},
+		bpf.JumpIf{
+			Cond:     bpf.JumpEqual,
+			Val:      0x01,
+			SkipTrue: 1,
+		},
+		bpf.RetConstant{
+			Val: 0,
+		},
+		bpf.RetConstant{
+			Val: 9,
+		},
+	})
+	if err != nil {
+		t.Fatalf("failed to load BPF program: %v", err)
+	}
+	defer done()
+
+	out, err := vm.Run([]byte{
+		0xff, 0xff, 0xff, 0xff,
+		0xff, 0xff, 0xff, 0xff,
+		0x0b, 0x00, 0x00, 0x00,
+	})
+	if err != nil {
+		t.Fatalf("unexpected error while running program: %v", err)
+	}
+	if want, got := 1, out; want != got {
+		t.Fatalf("unexpected number of output bytes:\n- want: %d\n-  got: %d",
+			want, got)
+	}
+}
+
+func TestVMALUOpUnknown(t *testing.T) {
+	vm, done, err := testVM(t, []bpf.Instruction{
+		bpf.LoadAbsolute{
+			Off:  8,
+			Size: 1,
+		},
+		bpf.ALUOpConstant{
+			Op:  bpf.ALUOpAdd,
+			Val: 1,
+		},
+		// Verify that an unknown operation is a no-op
+		bpf.ALUOpConstant{
+			Op: 100,
+		},
+		bpf.JumpIf{
+			Cond:     bpf.JumpEqual,
+			Val:      0x02,
+			SkipTrue: 1,
+		},
+		bpf.RetConstant{
+			Val: 0,
+		},
+		bpf.RetConstant{
+			Val: 9,
+		},
+	})
+	if err != nil {
+		t.Fatalf("failed to load BPF program: %v", err)
+	}
+	defer done()
+
+	out, err := vm.Run([]byte{
+		0xff, 0xff, 0xff, 0xff,
+		0xff, 0xff, 0xff, 0xff,
+		1,
+	})
+	if err != nil {
+		t.Fatalf("unexpected error while running program: %v", err)
+	}
+	if want, got := 1, out; want != got {
+		t.Fatalf("unexpected number of output bytes:\n- want: %d\n-  got: %d",
+			want, got)
+	}
+}

vendor/golang.org/x/net/bpf/vm_bpf_test.go

@@ -0,0 +1,192 @@
+// Copyright 2016 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 bpf_test
+
+import (
+	"net"
+	"runtime"
+	"testing"
+	"time"
+
+	"golang.org/x/net/bpf"
+	"golang.org/x/net/ipv4"
+)
+
+// A virtualMachine is a BPF virtual machine which can process an
+// input packet against a BPF program and render a verdict.
+type virtualMachine interface {
+	Run(in []byte) (int, error)
+}
+
+// canUseOSVM indicates if the OS BPF VM is available on this platform.
+func canUseOSVM() bool {
+	// OS BPF VM can only be used on platforms where x/net/ipv4 supports
+	// attaching a BPF program to a socket.
+	switch runtime.GOOS {
+	case "linux":
+		return true
+	}
+
+	return false
+}
+
+// All BPF tests against both the Go VM and OS VM are assumed to
+// be used with a UDP socket. As a result, the entire contents
+// of a UDP datagram is sent through the BPF program, but only
+// the body after the UDP header will ever be returned in output.
+
+// testVM sets up a Go BPF VM, and if available, a native OS BPF VM
+// for integration testing.
+func testVM(t *testing.T, filter []bpf.Instruction) (virtualMachine, func(), error) {
+	goVM, err := bpf.NewVM(filter)
+	if err != nil {
+		// Some tests expect an error, so this error must be returned
+		// instead of fatally exiting the test
+		return nil, nil, err
+	}
+
+	mvm := &multiVirtualMachine{
+		goVM: goVM,
+
+		t: t,
+	}
+
+	// If available, add the OS VM for tests which verify that both the Go
+	// VM and OS VM have exactly the same output for the same input program
+	// and packet.
+	done := func() {}
+	if canUseOSVM() {
+		osVM, osVMDone := testOSVM(t, filter)
+		done = func() { osVMDone() }
+		mvm.osVM = osVM
+	}
+
+	return mvm, done, nil
+}
+
+// udpHeaderLen is the length of a UDP header.
+const udpHeaderLen = 8
+
+// A multiVirtualMachine is a virtualMachine which can call out to both the Go VM
+// and the native OS VM, if the OS VM is available.
+type multiVirtualMachine struct {
+	goVM virtualMachine
+	osVM virtualMachine
+
+	t *testing.T
+}
+
+func (mvm *multiVirtualMachine) Run(in []byte) (int, error) {
+	if len(in) < udpHeaderLen {
+		mvm.t.Fatalf("input must be at least length of UDP header (%d), got: %d",
+			udpHeaderLen, len(in))
+	}
+
+	// All tests have a UDP header as part of input, because the OS VM
+	// packets always will. For the Go VM, this output is trimmed before
+	// being sent back to tests.
+	goOut, goErr := mvm.goVM.Run(in)
+	if goOut >= udpHeaderLen {
+		goOut -= udpHeaderLen
+	}
+
+	// If Go output is larger than the size of the packet, packet filtering
+	// interop tests must trim the output bytes to the length of the packet.
+	// The BPF VM should not do this on its own, as other uses of it do
+	// not trim the output byte count.
+	trim := len(in) - udpHeaderLen
+	if goOut > trim {
+		goOut = trim
+	}
+
+	// When the OS VM is not available, process using the Go VM alone
+	if mvm.osVM == nil {
+		return goOut, goErr
+	}
+
+	// The OS VM will apply its own UDP header, so remove the pseudo header
+	// that the Go VM needs.
+	osOut, err := mvm.osVM.Run(in[udpHeaderLen:])
+	if err != nil {
+		mvm.t.Fatalf("error while running OS VM: %v", err)
+	}
+
+	// Verify both VMs return same number of bytes
+	var mismatch bool
+	if goOut != osOut {
+		mismatch = true
+		mvm.t.Logf("output byte count does not match:\n- go: %v\n- os: %v", goOut, osOut)
+	}
+
+	if mismatch {
+		mvm.t.Fatal("Go BPF and OS BPF packet outputs do not match")
+	}
+
+	return goOut, goErr
+}
+
+// An osVirtualMachine is a virtualMachine which uses the OS's BPF VM for
+// processing BPF programs.
+type osVirtualMachine struct {
+	l net.PacketConn
+	s net.Conn
+}
+
+// testOSVM creates a virtualMachine which uses the OS's BPF VM by injecting
+// packets into a UDP listener with a BPF program attached to it.
+func testOSVM(t *testing.T, filter []bpf.Instruction) (virtualMachine, func()) {
+	l, err := net.ListenPacket("udp4", "127.0.0.1:0")
+	if err != nil {
+		t.Fatalf("failed to open OS VM UDP listener: %v", err)
+	}
+
+	prog, err := bpf.Assemble(filter)
+	if err != nil {
+		t.Fatalf("failed to compile BPF program: %v", err)
+	}
+
+	p := ipv4.NewPacketConn(l)
+	if err = p.SetBPF(prog); err != nil {
+		t.Fatalf("failed to attach BPF program to listener: %v", err)
+	}
+
+	s, err := net.Dial("udp4", l.LocalAddr().String())
+	if err != nil {
+		t.Fatalf("failed to dial connection to listener: %v", err)
+	}
+
+	done := func() {
+		_ = s.Close()
+		_ = l.Close()
+	}
+
+	return &osVirtualMachine{
+		l: l,
+		s: s,
+	}, done
+}
+
+// Run sends the input bytes into the OS's BPF VM and returns its verdict.
+func (vm *osVirtualMachine) Run(in []byte) (int, error) {
+	go func() {
+		_, _ = vm.s.Write(in)
+	}()
+
+	vm.l.SetDeadline(time.Now().Add(50 * time.Millisecond))
+
+	var b [512]byte
+	n, _, err := vm.l.ReadFrom(b[:])
+	if err != nil {
+		// A timeout indicates that BPF filtered out the packet, and thus,
+		// no input should be returned.
+		if nerr, ok := err.(net.Error); ok && nerr.Timeout() {
+			return n, nil
+		}
+
+		return n, err
+	}
+
+	return n, nil
+}

vendor/golang.org/x/net/bpf/vm_extension_test.go

@@ -0,0 +1,49 @@
+// Copyright 2016 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 bpf_test
+
+import (
+	"testing"
+
+	"golang.org/x/net/bpf"
+)
+
+func TestVMLoadExtensionNotImplemented(t *testing.T) {
+	_, _, err := testVM(t, []bpf.Instruction{
+		bpf.LoadExtension{
+			Num: 100,
+		},
+		bpf.RetA{},
+	})
+	if errStr(err) != "extension 100 not implemented" {
+		t.Fatalf("unexpected error: %v", err)
+	}
+}
+
+func TestVMLoadExtensionExtLen(t *testing.T) {
+	vm, done, err := testVM(t, []bpf.Instruction{
+		bpf.LoadExtension{
+			Num: bpf.ExtLen,
+		},
+		bpf.RetA{},
+	})
+	if err != nil {
+		t.Fatalf("failed to load BPF program: %v", err)
+	}
+	defer done()
+
+	out, err := vm.Run([]byte{
+		0xff, 0xff, 0xff, 0xff,
+		0xff, 0xff, 0xff, 0xff,
+		0, 1, 2, 3,
+	})
+	if err != nil {
+		t.Fatalf("unexpected error while running program: %v", err)
+	}
+	if want, got := 4, out; want != got {
+		t.Fatalf("unexpected number of output bytes:\n- want: %d\n-  got: %d",
+			want, got)
+	}
+}

vendor/golang.org/x/net/bpf/vm_instructions.go

@@ -0,0 +1,174 @@
+// Copyright 2016 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 bpf
+
+import (
+	"encoding/binary"
+	"fmt"
+)
+
+func aluOpConstant(ins ALUOpConstant, regA uint32) uint32 {
+	return aluOpCommon(ins.Op, regA, ins.Val)
+}
+
+func aluOpX(ins ALUOpX, regA uint32, regX uint32) (uint32, bool) {
+	// Guard against division or modulus by zero by terminating
+	// the program, as the OS BPF VM does
+	if regX == 0 {
+		switch ins.Op {
+		case ALUOpDiv, ALUOpMod:
+			return 0, false
+		}
+	}
+
+	return aluOpCommon(ins.Op, regA, regX), true
+}
+
+func aluOpCommon(op ALUOp, regA uint32, value uint32) uint32 {
+	switch op {
+	case ALUOpAdd:
+		return regA + value
+	case ALUOpSub:
+		return regA - value
+	case ALUOpMul:
+		return regA * value
+	case ALUOpDiv:
+		// Division by zero not permitted by NewVM and aluOpX checks
+		return regA / value
+	case ALUOpOr:
+		return regA | value
+	case ALUOpAnd:
+		return regA & value
+	case ALUOpShiftLeft:
+		return regA << value
+	case ALUOpShiftRight:
+		return regA >> value
+	case ALUOpMod:
+		// Modulus by zero not permitted by NewVM and aluOpX checks
+		return regA % value
+	case ALUOpXor:
+		return regA ^ value
+	default:
+		return regA
+	}
+}
+
+func jumpIf(ins JumpIf, value uint32) int {
+	var ok bool
+	inV := uint32(ins.Val)
+
+	switch ins.Cond {
+	case JumpEqual:
+		ok = value == inV
+	case JumpNotEqual:
+		ok = value != inV
+	case JumpGreaterThan:
+		ok = value > inV
+	case JumpLessThan:
+		ok = value < inV
+	case JumpGreaterOrEqual:
+		ok = value >= inV
+	case JumpLessOrEqual:
+		ok = value <= inV
+	case JumpBitsSet:
+		ok = (value & inV) != 0
+	case JumpBitsNotSet:
+		ok = (value & inV) == 0
+	}
+
+	if ok {
+		return int(ins.SkipTrue)
+	}
+
+	return int(ins.SkipFalse)
+}
+
+func loadAbsolute(ins LoadAbsolute, in []byte) (uint32, bool) {
+	offset := int(ins.Off)
+	size := int(ins.Size)
+
+	return loadCommon(in, offset, size)
+}
+
+func loadConstant(ins LoadConstant, regA uint32, regX uint32) (uint32, uint32) {
+	switch ins.Dst {
+	case RegA:
+		regA = ins.Val
+	case RegX:
+		regX = ins.Val
+	}
+
+	return regA, regX
+}
+
+func loadExtension(ins LoadExtension, in []byte) uint32 {
+	switch ins.Num {
+	case ExtLen:
+		return uint32(len(in))
+	default:
+		panic(fmt.Sprintf("unimplemented extension: %d", ins.Num))
+	}
+}
+
+func loadIndirect(ins LoadIndirect, in []byte, regX uint32) (uint32, bool) {
+	offset := int(ins.Off) + int(regX)
+	size := int(ins.Size)
+
+	return loadCommon(in, offset, size)
+}
+
+func loadMemShift(ins LoadMemShift, in []byte) (uint32, bool) {
+	offset := int(ins.Off)
+
+	if !inBounds(len(in), offset, 0) {
+		return 0, false
+	}
+
+	// Mask off high 4 bits and multiply low 4 bits by 4
+	return uint32(in[offset]&0x0f) * 4, true
+}
+
+func inBounds(inLen int, offset int, size int) bool {
+	return offset+size <= inLen
+}
+
+func loadCommon(in []byte, offset int, size int) (uint32, bool) {
+	if !inBounds(len(in), offset, size) {
+		return 0, false
+	}
+
+	switch size {
+	case 1:
+		return uint32(in[offset]), true
+	case 2:
+		return uint32(binary.BigEndian.Uint16(in[offset : offset+size])), true
+	case 4:
+		return uint32(binary.BigEndian.Uint32(in[offset : offset+size])), true
+	default:
+		panic(fmt.Sprintf("invalid load size: %d", size))
+	}
+}
+
+func loadScratch(ins LoadScratch, regScratch [16]uint32, regA uint32, regX uint32) (uint32, uint32) {
+	switch ins.Dst {
+	case RegA:
+		regA = regScratch[ins.N]
+	case RegX:
+		regX = regScratch[ins.N]
+	}
+
+	return regA, regX
+}
+
+func storeScratch(ins StoreScratch, regScratch [16]uint32, regA uint32, regX uint32) [16]uint32 {
+	switch ins.Src {
+	case RegA:
+		regScratch[ins.N] = regA
+	case RegX:
+		regScratch[ins.N] = regX
+	}
+
+	return regScratch
+}

vendor/golang.org/x/net/bpf/vm_jump_test.go

@@ -0,0 +1,380 @@
+// Copyright 2016 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 bpf_test
+
+import (
+	"testing"
+
+	"golang.org/x/net/bpf"
+)
+
+func TestVMJumpOne(t *testing.T) {
+	vm, done, err := testVM(t, []bpf.Instruction{
+		bpf.LoadAbsolute{
+			Off:  8,
+			Size: 1,
+		},
+		bpf.Jump{
+			Skip: 1,
+		},
+		bpf.RetConstant{
+			Val: 0,
+		},
+		bpf.RetConstant{
+			Val: 9,
+		},
+	})
+	if err != nil {
+		t.Fatalf("failed to load BPF program: %v", err)
+	}
+	defer done()
+
+	out, err := vm.Run([]byte{
+		0xff, 0xff, 0xff, 0xff,
+		0xff, 0xff, 0xff, 0xff,
+		1,
+	})
+	if err != nil {
+		t.Fatalf("unexpected error while running program: %v", err)
+	}
+	if want, got := 1, out; want != got {
+		t.Fatalf("unexpected number of output bytes:\n- want: %d\n-  got: %d",
+			want, got)
+	}
+}
+
+func TestVMJumpOutOfProgram(t *testing.T) {
+	_, _, err := testVM(t, []bpf.Instruction{
+		bpf.Jump{
+			Skip: 1,
+		},
+		bpf.RetA{},
+	})
+	if errStr(err) != "cannot jump 1 instructions; jumping past program bounds" {
+		t.Fatalf("unexpected error: %v", err)
+	}
+}
+
+func TestVMJumpIfTrueOutOfProgram(t *testing.T) {
+	_, _, err := testVM(t, []bpf.Instruction{
+		bpf.JumpIf{
+			Cond:     bpf.JumpEqual,
+			SkipTrue: 2,
+		},
+		bpf.RetA{},
+	})
+	if errStr(err) != "cannot jump 2 instructions in true case; jumping past program bounds" {
+		t.Fatalf("unexpected error: %v", err)
+	}
+}
+
+func TestVMJumpIfFalseOutOfProgram(t *testing.T) {
+	_, _, err := testVM(t, []bpf.Instruction{
+		bpf.JumpIf{
+			Cond:      bpf.JumpEqual,
+			SkipFalse: 3,
+		},
+		bpf.RetA{},
+	})
+	if errStr(err) != "cannot jump 3 instructions in false case; jumping past program bounds" {
+		t.Fatalf("unexpected error: %v", err)
+	}
+}
+
+func TestVMJumpIfEqual(t *testing.T) {
+	vm, done, err := testVM(t, []bpf.Instruction{
+		bpf.LoadAbsolute{
+			Off:  8,
+			Size: 1,
+		},
+		bpf.JumpIf{
+			Cond:     bpf.JumpEqual,
+			Val:      1,
+			SkipTrue: 1,
+		},
+		bpf.RetConstant{
+			Val: 0,
+		},
+		bpf.RetConstant{
+			Val: 9,
+		},
+	})
+	if err != nil {
+		t.Fatalf("failed to load BPF program: %v", err)
+	}
+	defer done()
+
+	out, err := vm.Run([]byte{
+		0xff, 0xff, 0xff, 0xff,
+		0xff, 0xff, 0xff, 0xff,
+		1,
+	})
+	if err != nil {
+		t.Fatalf("unexpected error while running program: %v", err)
+	}
+	if want, got := 1, out; want != got {
+		t.Fatalf("unexpected number of output bytes:\n- want: %d\n-  got: %d",
+			want, got)
+	}
+}
+
+func TestVMJumpIfNotEqual(t *testing.T) {
+	vm, done, err := testVM(t, []bpf.Instruction{
+		bpf.LoadAbsolute{
+			Off:  8,
+			Size: 1,
+		},
+		bpf.JumpIf{
+			Cond:      bpf.JumpNotEqual,
+			Val:       1,
+			SkipFalse: 1,
+		},
+		bpf.RetConstant{
+			Val: 0,
+		},
+		bpf.RetConstant{
+			Val: 9,
+		},
+	})
+	if err != nil {
+		t.Fatalf("failed to load BPF program: %v", err)
+	}
+	defer done()
+
+	out, err := vm.Run([]byte{
+		0xff, 0xff, 0xff, 0xff,
+		0xff, 0xff, 0xff, 0xff,
+		1,
+	})
+	if err != nil {
+		t.Fatalf("unexpected error while running program: %v", err)
+	}
+	if want, got := 1, out; want != got {
+		t.Fatalf("unexpected number of output bytes:\n- want: %d\n-  got: %d",
+			want, got)
+	}
+}
+
+func TestVMJumpIfGreaterThan(t *testing.T) {
+	vm, done, err := testVM(t, []bpf.Instruction{
+		bpf.LoadAbsolute{
+			Off:  8,
+			Size: 4,
+		},
+		bpf.JumpIf{
+			Cond:     bpf.JumpGreaterThan,
+			Val:      0x00010202,
+			SkipTrue: 1,
+		},
+		bpf.RetConstant{
+			Val: 0,
+		},
+		bpf.RetConstant{
+			Val: 12,
+		},
+	})
+	if err != nil {
+		t.Fatalf("failed to load BPF program: %v", err)
+	}
+	defer done()
+
+	out, err := vm.Run([]byte{
+		0xff, 0xff, 0xff, 0xff,
+		0xff, 0xff, 0xff, 0xff,
+		0, 1, 2, 3,
+	})
+	if err != nil {
+		t.Fatalf("unexpected error while running program: %v", err)
+	}
+	if want, got := 4, out; want != got {
+		t.Fatalf("unexpected number of output bytes:\n- want: %d\n-  got: %d",
+			want, got)
+	}
+}
+
+func TestVMJumpIfLessThan(t *testing.T) {
+	vm, done, err := testVM(t, []bpf.Instruction{
+		bpf.LoadAbsolute{
+			Off:  8,
+			Size: 4,
+		},
+		bpf.JumpIf{
+			Cond:     bpf.JumpLessThan,
+			Val:      0xff010203,
+			SkipTrue: 1,
+		},
+		bpf.RetConstant{
+			Val: 0,
+		},
+		bpf.RetConstant{
+			Val: 12,
+		},
+	})
+	if err != nil {
+		t.Fatalf("failed to load BPF program: %v", err)
+	}
+	defer done()
+
+	out, err := vm.Run([]byte{
+		0xff, 0xff, 0xff, 0xff,
+		0xff, 0xff, 0xff, 0xff,
+		0, 1, 2, 3,
+	})
+	if err != nil {
+		t.Fatalf("unexpected error while running program: %v", err)
+	}
+	if want, got := 4, out; want != got {
+		t.Fatalf("unexpected number of output bytes:\n- want: %d\n-  got: %d",
+			want, got)
+	}
+}
+
+func TestVMJumpIfGreaterOrEqual(t *testing.T) {
+	vm, done, err := testVM(t, []bpf.Instruction{
+		bpf.LoadAbsolute{
+			Off:  8,
+			Size: 4,
+		},
+		bpf.JumpIf{
+			Cond:     bpf.JumpGreaterOrEqual,
+			Val:      0x00010203,
+			SkipTrue: 1,
+		},
+		bpf.RetConstant{
+			Val: 0,
+		},
+		bpf.RetConstant{
+			Val: 12,
+		},
+	})
+	if err != nil {
+		t.Fatalf("failed to load BPF program: %v", err)
+	}
+	defer done()
+
+	out, err := vm.Run([]byte{
+		0xff, 0xff, 0xff, 0xff,
+		0xff, 0xff, 0xff, 0xff,
+		0, 1, 2, 3,
+	})
+	if err != nil {
+		t.Fatalf("unexpected error while running program: %v", err)
+	}
+	if want, got := 4, out; want != got {
+		t.Fatalf("unexpected number of output bytes:\n- want: %d\n-  got: %d",
+			want, got)
+	}
+}
+
+func TestVMJumpIfLessOrEqual(t *testing.T) {
+	vm, done, err := testVM(t, []bpf.Instruction{
+		bpf.LoadAbsolute{
+			Off:  8,
+			Size: 4,
+		},
+		bpf.JumpIf{
+			Cond:     bpf.JumpLessOrEqual,
+			Val:      0xff010203,
+			SkipTrue: 1,
+		},
+		bpf.RetConstant{
+			Val: 0,
+		},
+		bpf.RetConstant{
+			Val: 12,
+		},
+	})
+	if err != nil {
+		t.Fatalf("failed to load BPF program: %v", err)
+	}
+	defer done()
+
+	out, err := vm.Run([]byte{
+		0xff, 0xff, 0xff, 0xff,
+		0xff, 0xff, 0xff, 0xff,
+		0, 1, 2, 3,
+	})
+	if err != nil {
+		t.Fatalf("unexpected error while running program: %v", err)
+	}
+	if want, got := 4, out; want != got {
+		t.Fatalf("unexpected number of output bytes:\n- want: %d\n-  got: %d",
+			want, got)
+	}
+}
+
+func TestVMJumpIfBitsSet(t *testing.T) {
+	vm, done, err := testVM(t, []bpf.Instruction{
+		bpf.LoadAbsolute{
+			Off:  8,
+			Size: 2,
+		},
+		bpf.JumpIf{
+			Cond:     bpf.JumpBitsSet,
+			Val:      0x1122,
+			SkipTrue: 1,
+		},
+		bpf.RetConstant{
+			Val: 0,
+		},
+		bpf.RetConstant{
+			Val: 10,
+		},
+	})
+	if err != nil {
+		t.Fatalf("failed to load BPF program: %v", err)
+	}
+	defer done()
+
+	out, err := vm.Run([]byte{
+		0xff, 0xff, 0xff, 0xff,
+		0xff, 0xff, 0xff, 0xff,
+		0x01, 0x02,
+	})
+	if err != nil {
+		t.Fatalf("unexpected error while running program: %v", err)
+	}
+	if want, got := 2, out; want != got {
+		t.Fatalf("unexpected number of output bytes:\n- want: %d\n-  got: %d",
+			want, got)
+	}
+}
+
+func TestVMJumpIfBitsNotSet(t *testing.T) {
+	vm, done, err := testVM(t, []bpf.Instruction{
+		bpf.LoadAbsolute{
+			Off:  8,
+			Size: 2,
+		},
+		bpf.JumpIf{
+			Cond:     bpf.JumpBitsNotSet,
+			Val:      0x1221,
+			SkipTrue: 1,
+		},
+		bpf.RetConstant{
+			Val: 0,
+		},
+		bpf.RetConstant{
+			Val: 10,
+		},
+	})
+	if err != nil {
+		t.Fatalf("failed to load BPF program: %v", err)
+	}
+	defer done()
+
+	out, err := vm.Run([]byte{
+		0xff, 0xff, 0xff, 0xff,
+		0xff, 0xff, 0xff, 0xff,
+		0x01, 0x02,
+	})
+	if err != nil {
+		t.Fatalf("unexpected error while running program: %v", err)
+	}
+	if want, got := 2, out; want != got {
+		t.Fatalf("unexpected number of output bytes:\n- want: %d\n-  got: %d",
+			want, got)
+	}
+}

vendor/golang.org/x/net/bpf/vm_load_test.go

@@ -0,0 +1,246 @@
+// Copyright 2016 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 bpf_test
+
+import (
+	"net"
+	"testing"
+
+	"golang.org/x/net/bpf"
+	"golang.org/x/net/ipv4"
+)
+
+func TestVMLoadAbsoluteOffsetOutOfBounds(t *testing.T) {
+	vm, done, err := testVM(t, []bpf.Instruction{
+		bpf.LoadAbsolute{
+			Off:  100,
+			Size: 2,
+		},
+		bpf.RetA{},
+	})
+	if err != nil {
+		t.Fatalf("failed to load BPF program: %v", err)
+	}
+	defer done()
+
+	out, err := vm.Run([]byte{
+		0xff, 0xff, 0xff, 0xff,
+		0xff, 0xff, 0xff, 0xff,
+		0, 1, 2, 3,
+	})
+	if err != nil {
+		t.Fatalf("unexpected error while running program: %v", err)
+	}
+	if want, got := 0, out; want != got {
+		t.Fatalf("unexpected number of output bytes:\n- want: %d\n-  got: %d",
+			want, got)
+	}
+}
+
+func TestVMLoadAbsoluteOffsetPlusSizeOutOfBounds(t *testing.T) {
+	vm, done, err := testVM(t, []bpf.Instruction{
+		bpf.LoadAbsolute{
+			Off:  8,
+			Size: 2,
+		},
+		bpf.RetA{},
+	})
+	if err != nil {
+		t.Fatalf("failed to load BPF program: %v", err)
+	}
+	defer done()
+
+	out, err := vm.Run([]byte{
+		0xff, 0xff, 0xff, 0xff,
+		0xff, 0xff, 0xff, 0xff,
+		0,
+	})
+	if err != nil {
+		t.Fatalf("unexpected error while running program: %v", err)
+	}
+	if want, got := 0, out; want != got {
+		t.Fatalf("unexpected number of output bytes:\n- want: %d\n-  got: %d",
+			want, got)
+	}
+}
+
+func TestVMLoadAbsoluteBadInstructionSize(t *testing.T) {
+	_, _, err := testVM(t, []bpf.Instruction{
+		bpf.LoadAbsolute{
+			Size: 5,
+		},
+		bpf.RetA{},
+	})
+	if errStr(err) != "assembling instruction 1: invalid load byte length 0" {
+		t.Fatalf("unexpected error: %v", err)
+	}
+}
+
+func TestVMLoadConstantOK(t *testing.T) {
+	vm, done, err := testVM(t, []bpf.Instruction{
+		bpf.LoadConstant{
+			Dst: bpf.RegX,
+			Val: 9,
+		},
+		bpf.TXA{},
+		bpf.RetA{},
+	})
+	if err != nil {
+		t.Fatalf("failed to load BPF program: %v", err)
+	}
+	defer done()
+
+	out, err := vm.Run([]byte{
+		0xff, 0xff, 0xff, 0xff,
+		0xff, 0xff, 0xff, 0xff,
+		0,
+	})
+	if err != nil {
+		t.Fatalf("unexpected error while running program: %v", err)
+	}
+	if want, got := 1, out; want != got {
+		t.Fatalf("unexpected number of output bytes:\n- want: %d\n-  got: %d",
+			want, got)
+	}
+}
+
+func TestVMLoadIndirectOutOfBounds(t *testing.T) {
+	vm, done, err := testVM(t, []bpf.Instruction{
+		bpf.LoadIndirect{
+			Off:  100,
+			Size: 1,
+		},
+		bpf.RetA{},
+	})
+	if err != nil {
+		t.Fatalf("failed to load BPF program: %v", err)
+	}
+	defer done()
+
+	out, err := vm.Run([]byte{
+		0xff, 0xff, 0xff, 0xff,
+		0xff, 0xff, 0xff, 0xff,
+		0,
+	})
+	if err != nil {
+		t.Fatalf("unexpected error while running program: %v", err)
+	}
+	if want, got := 0, out; want != got {
+		t.Fatalf("unexpected number of output bytes:\n- want: %d\n-  got: %d",
+			want, got)
+	}
+}
+
+func TestVMLoadMemShiftOutOfBounds(t *testing.T) {
+	vm, done, err := testVM(t, []bpf.Instruction{
+		bpf.LoadMemShift{
+			Off: 100,
+		},
+		bpf.RetA{},
+	})
+	if err != nil {
+		t.Fatalf("failed to load BPF program: %v", err)
+	}
+	defer done()
+
+	out, err := vm.Run([]byte{
+		0xff, 0xff, 0xff, 0xff,
+		0xff, 0xff, 0xff, 0xff,
+		0,
+	})
+	if err != nil {
+		t.Fatalf("unexpected error while running program: %v", err)
+	}
+	if want, got := 0, out; want != got {
+		t.Fatalf("unexpected number of output bytes:\n- want: %d\n-  got: %d",
+			want, got)
+	}
+}
+
+const (
+	dhcp4Port = 53
+)
+
+func TestVMLoadMemShiftLoadIndirectNoResult(t *testing.T) {
+	vm, in, done := testDHCPv4(t)
+	defer done()
+
+	// Append mostly empty UDP header with incorrect DHCPv4 port
+	in = append(in, []byte{
+		0, 0,
+		0, dhcp4Port + 1,
+		0, 0,
+		0, 0,
+	}...)
+
+	out, err := vm.Run(in)
+	if err != nil {
+		t.Fatalf("unexpected error while running program: %v", err)
+	}
+	if want, got := 0, out; want != got {
+		t.Fatalf("unexpected number of output bytes:\n- want: %d\n-  got: %d",
+			want, got)
+	}
+}
+
+func TestVMLoadMemShiftLoadIndirectOK(t *testing.T) {
+	vm, in, done := testDHCPv4(t)
+	defer done()
+
+	// Append mostly empty UDP header with correct DHCPv4 port
+	in = append(in, []byte{
+		0, 0,
+		0, dhcp4Port,
+		0, 0,
+		0, 0,
+	}...)
+
+	out, err := vm.Run(in)
+	if err != nil {
+		t.Fatalf("unexpected error while running program: %v", err)
+	}
+	if want, got := len(in)-8, out; want != got {
+		t.Fatalf("unexpected number of output bytes:\n- want: %d\n-  got: %d",
+			want, got)
+	}
+}
+
+func testDHCPv4(t *testing.T) (virtualMachine, []byte, func()) {
+	// DHCPv4 test data courtesy of David Anderson:
+	// https://github.com/google/netboot/blob/master/dhcp4/conn_linux.go#L59-L70
+	vm, done, err := testVM(t, []bpf.Instruction{
+		// Load IPv4 packet length
+		bpf.LoadMemShift{Off: 8},
+		// Get UDP dport
+		bpf.LoadIndirect{Off: 8 + 2, Size: 2},
+		// Correct dport?
+		bpf.JumpIf{Cond: bpf.JumpEqual, Val: dhcp4Port, SkipFalse: 1},
+		// Accept
+		bpf.RetConstant{Val: 1500},
+		// Ignore
+		bpf.RetConstant{Val: 0},
+	})
+	if err != nil {
+		t.Fatalf("failed to load BPF program: %v", err)
+	}
+
+	// Minimal requirements to make a valid IPv4 header
+	h := &ipv4.Header{
+		Len: ipv4.HeaderLen,
+		Src: net.IPv4(192, 168, 1, 1),
+		Dst: net.IPv4(192, 168, 1, 2),
+	}
+	hb, err := h.Marshal()
+	if err != nil {
+		t.Fatalf("failed to marshal IPv4 header: %v", err)
+	}
+
+	hb = append([]byte{
+		0xff, 0xff, 0xff, 0xff,
+		0xff, 0xff, 0xff, 0xff,
+	}, hb...)
+
+	return vm, hb, done
+}

vendor/golang.org/x/net/bpf/vm_ret_test.go

@@ -0,0 +1,115 @@
+// Copyright 2016 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 bpf_test
+
+import (
+	"testing"
+
+	"golang.org/x/net/bpf"
+)
+
+func TestVMRetA(t *testing.T) {
+	vm, done, err := testVM(t, []bpf.Instruction{
+		bpf.LoadAbsolute{
+			Off:  8,
+			Size: 1,
+		},
+		bpf.RetA{},
+	})
+	if err != nil {
+		t.Fatalf("failed to load BPF program: %v", err)
+	}
+	defer done()
+
+	out, err := vm.Run([]byte{
+		0xff, 0xff, 0xff, 0xff,
+		0xff, 0xff, 0xff, 0xff,
+		9,
+	})
+	if err != nil {
+		t.Fatalf("unexpected error while running program: %v", err)
+	}
+	if want, got := 1, out; want != got {
+		t.Fatalf("unexpected number of output bytes:\n- want: %d\n-  got: %d",
+			want, got)
+	}
+}
+
+func TestVMRetALargerThanInput(t *testing.T) {
+	vm, done, err := testVM(t, []bpf.Instruction{
+		bpf.LoadAbsolute{
+			Off:  8,
+			Size: 2,
+		},
+		bpf.RetA{},
+	})
+	if err != nil {
+		t.Fatalf("failed to load BPF program: %v", err)
+	}
+	defer done()
+
+	out, err := vm.Run([]byte{
+		0xff, 0xff, 0xff, 0xff,
+		0xff, 0xff, 0xff, 0xff,
+		0, 255,
+	})
+	if err != nil {
+		t.Fatalf("unexpected error while running program: %v", err)
+	}
+	if want, got := 2, out; want != got {
+		t.Fatalf("unexpected number of output bytes:\n- want: %d\n-  got: %d",
+			want, got)
+	}
+}
+
+func TestVMRetConstant(t *testing.T) {
+	vm, done, err := testVM(t, []bpf.Instruction{
+		bpf.RetConstant{
+			Val: 9,
+		},
+	})
+	if err != nil {
+		t.Fatalf("failed to load BPF program: %v", err)
+	}
+	defer done()
+
+	out, err := vm.Run([]byte{
+		0xff, 0xff, 0xff, 0xff,
+		0xff, 0xff, 0xff, 0xff,
+		0, 1,
+	})
+	if err != nil {
+		t.Fatalf("unexpected error while running program: %v", err)
+	}
+	if want, got := 1, out; want != got {
+		t.Fatalf("unexpected number of output bytes:\n- want: %d\n-  got: %d",
+			want, got)
+	}
+}
+
+func TestVMRetConstantLargerThanInput(t *testing.T) {
+	vm, done, err := testVM(t, []bpf.Instruction{
+		bpf.RetConstant{
+			Val: 16,
+		},
+	})
+	if err != nil {
+		t.Fatalf("failed to load BPF program: %v", err)
+	}
+	defer done()
+
+	out, err := vm.Run([]byte{
+		0xff, 0xff, 0xff, 0xff,
+		0xff, 0xff, 0xff, 0xff,
+		0, 1,
+	})
+	if err != nil {
+		t.Fatalf("unexpected error while running program: %v", err)
+	}
+	if want, got := 2, out; want != got {
+		t.Fatalf("unexpected number of output bytes:\n- want: %d\n-  got: %d",
+			want, got)
+	}
+}

vendor/golang.org/x/net/bpf/vm_scratch_test.go

@@ -0,0 +1,247 @@
+// Copyright 2016 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 bpf_test
+
+import (
+	"testing"
+
+	"golang.org/x/net/bpf"
+)
+
+func TestVMStoreScratchInvalidScratchRegisterTooSmall(t *testing.T) {
+	_, _, err := testVM(t, []bpf.Instruction{
+		bpf.StoreScratch{
+			Src: bpf.RegA,
+			N:   -1,
+		},
+		bpf.RetA{},
+	})
+	if errStr(err) != "assembling instruction 1: invalid scratch slot -1" {
+		t.Fatalf("unexpected error: %v", err)
+	}
+}
+
+func TestVMStoreScratchInvalidScratchRegisterTooLarge(t *testing.T) {
+	_, _, err := testVM(t, []bpf.Instruction{
+		bpf.StoreScratch{
+			Src: bpf.RegA,
+			N:   16,
+		},
+		bpf.RetA{},
+	})
+	if errStr(err) != "assembling instruction 1: invalid scratch slot 16" {
+		t.Fatalf("unexpected error: %v", err)
+	}
+}
+
+func TestVMStoreScratchUnknownSourceRegister(t *testing.T) {
+	_, _, err := testVM(t, []bpf.Instruction{
+		bpf.StoreScratch{
+			Src: 100,
+			N:   0,
+		},
+		bpf.RetA{},
+	})
+	if errStr(err) != "assembling instruction 1: invalid source register 100" {
+		t.Fatalf("unexpected error: %v", err)
+	}
+}
+
+func TestVMLoadScratchInvalidScratchRegisterTooSmall(t *testing.T) {
+	_, _, err := testVM(t, []bpf.Instruction{
+		bpf.LoadScratch{
+			Dst: bpf.RegX,
+			N:   -1,
+		},
+		bpf.RetA{},
+	})
+	if errStr(err) != "assembling instruction 1: invalid scratch slot -1" {
+		t.Fatalf("unexpected error: %v", err)
+	}
+}
+
+func TestVMLoadScratchInvalidScratchRegisterTooLarge(t *testing.T) {
+	_, _, err := testVM(t, []bpf.Instruction{
+		bpf.LoadScratch{
+			Dst: bpf.RegX,
+			N:   16,
+		},
+		bpf.RetA{},
+	})
+	if errStr(err) != "assembling instruction 1: invalid scratch slot 16" {
+		t.Fatalf("unexpected error: %v", err)
+	}
+}
+
+func TestVMLoadScratchUnknownDestinationRegister(t *testing.T) {
+	_, _, err := testVM(t, []bpf.Instruction{
+		bpf.LoadScratch{
+			Dst: 100,
+			N:   0,
+		},
+		bpf.RetA{},
+	})
+	if errStr(err) != "assembling instruction 1: invalid target register 100" {
+		t.Fatalf("unexpected error: %v", err)
+	}
+}
+
+func TestVMStoreScratchLoadScratchOneValue(t *testing.T) {
+	vm, done, err := testVM(t, []bpf.Instruction{
+		// Load byte 255
+		bpf.LoadAbsolute{
+			Off:  8,
+			Size: 1,
+		},
+		// Copy to X and store in scratch[0]
+		bpf.TAX{},
+		bpf.StoreScratch{
+			Src: bpf.RegX,
+			N:   0,
+		},
+		// Load byte 1
+		bpf.LoadAbsolute{
+			Off:  9,
+			Size: 1,
+		},
+		// Overwrite 1 with 255 from scratch[0]
+		bpf.LoadScratch{
+			Dst: bpf.RegA,
+			N:   0,
+		},
+		// Return 255
+		bpf.RetA{},
+	})
+	if err != nil {
+		t.Fatalf("failed to load BPF program: %v", err)
+	}
+	defer done()
+
+	out, err := vm.Run([]byte{
+		0xff, 0xff, 0xff, 0xff,
+		0xff, 0xff, 0xff, 0xff,
+		255, 1, 2,
+	})
+	if err != nil {
+		t.Fatalf("unexpected error while running program: %v", err)
+	}
+	if want, got := 3, out; want != got {
+		t.Fatalf("unexpected number of output bytes:\n- want: %d\n-  got: %d",
+			want, got)
+	}
+}
+
+func TestVMStoreScratchLoadScratchMultipleValues(t *testing.T) {
+	vm, done, err := testVM(t, []bpf.Instruction{
+		// Load byte 10
+		bpf.LoadAbsolute{
+			Off:  8,
+			Size: 1,
+		},
+		// Store in scratch[0]
+		bpf.StoreScratch{
+			Src: bpf.RegA,
+			N:   0,
+		},
+		// Load byte 20
+		bpf.LoadAbsolute{
+			Off:  9,
+			Size: 1,
+		},
+		// Store in scratch[1]
+		bpf.StoreScratch{
+			Src: bpf.RegA,
+			N:   1,
+		},
+		// Load byte 30
+		bpf.LoadAbsolute{
+			Off:  10,
+			Size: 1,
+		},
+		// Store in scratch[2]
+		bpf.StoreScratch{
+			Src: bpf.RegA,
+			N:   2,
+		},
+		// Load byte 1
+		bpf.LoadAbsolute{
+			Off:  11,
+			Size: 1,
+		},
+		// Store in scratch[3]
+		bpf.StoreScratch{
+			Src: bpf.RegA,
+			N:   3,
+		},
+		// Load in byte 10 to X
+		bpf.LoadScratch{
+			Dst: bpf.RegX,
+			N:   0,
+		},
+		// Copy X -> A
+		bpf.TXA{},
+		// Verify value is 10
+		bpf.JumpIf{
+			Cond:     bpf.JumpEqual,
+			Val:      10,
+			SkipTrue: 1,
+		},
+		// Fail test if incorrect
+		bpf.RetConstant{
+			Val: 0,
+		},
+		// Load in byte 20 to A
+		bpf.LoadScratch{
+			Dst: bpf.RegA,
+			N:   1,
+		},
+		// Verify value is 20
+		bpf.JumpIf{
+			Cond:     bpf.JumpEqual,
+			Val:      20,
+			SkipTrue: 1,
+		},
+		// Fail test if incorrect
+		bpf.RetConstant{
+			Val: 0,
+		},
+		// Load in byte 30 to A
+		bpf.LoadScratch{
+			Dst: bpf.RegA,
+			N:   2,
+		},
+		// Verify value is 30
+		bpf.JumpIf{
+			Cond:     bpf.JumpEqual,
+			Val:      30,
+			SkipTrue: 1,
+		},
+		// Fail test if incorrect
+		bpf.RetConstant{
+			Val: 0,
+		},
+		// Return first two bytes on success
+		bpf.RetConstant{
+			Val: 10,
+		},
+	})
+	if err != nil {
+		t.Fatalf("failed to load BPF program: %v", err)
+	}
+	defer done()
+
+	out, err := vm.Run([]byte{
+		0xff, 0xff, 0xff, 0xff,
+		0xff, 0xff, 0xff, 0xff,
+		10, 20, 30, 1,
+	})
+	if err != nil {
+		t.Fatalf("unexpected error while running program: %v", err)
+	}
+	if want, got := 2, out; want != got {
+		t.Fatalf("unexpected number of output bytes:\n- want: %d\n-  got: %d",
+			want, got)
+	}
+}

vendor/golang.org/x/net/bpf/vm_test.go

@@ -0,0 +1,144 @@
+// Copyright 2016 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 bpf_test
+
+import (
+	"fmt"
+	"testing"
+
+	"golang.org/x/net/bpf"
+)
+
+var _ bpf.Instruction = unknown{}
+
+type unknown struct{}
+
+func (unknown) Assemble() (bpf.RawInstruction, error) {
+	return bpf.RawInstruction{}, nil
+}
+
+func TestVMUnknownInstruction(t *testing.T) {
+	vm, done, err := testVM(t, []bpf.Instruction{
+		bpf.LoadConstant{
+			Dst: bpf.RegA,
+			Val: 100,
+		},
+		// Should terminate the program with an error immediately
+		unknown{},
+		bpf.RetA{},
+	})
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	defer done()
+
+	_, err = vm.Run([]byte{
+		0xff, 0xff, 0xff, 0xff,
+		0xff, 0xff, 0xff, 0xff,
+		0x00, 0x00,
+	})
+	if errStr(err) != "unknown Instruction at index 1: bpf_test.unknown" {
+		t.Fatalf("unexpected error while running program: %v", err)
+	}
+}
+
+func TestVMNoReturnInstruction(t *testing.T) {
+	_, _, err := testVM(t, []bpf.Instruction{
+		bpf.LoadConstant{
+			Dst: bpf.RegA,
+			Val: 1,
+		},
+	})
+	if errStr(err) != "BPF program must end with RetA or RetConstant" {
+		t.Fatalf("unexpected error: %v", err)
+	}
+}
+
+func TestVMNoInputInstructions(t *testing.T) {
+	_, _, err := testVM(t, []bpf.Instruction{})
+	if errStr(err) != "one or more Instructions must be specified" {
+		t.Fatalf("unexpected error: %v", err)
+	}
+}
+
+// ExampleNewVM demonstrates usage of a VM, using an Ethernet frame
+// as input and checking its EtherType to determine if it should be accepted.
+func ExampleNewVM() {
+	// Offset | Length | Comment
+	// -------------------------
+	//   00   |   06   | Ethernet destination MAC address
+	//   06   |   06   | Ethernet source MAC address
+	//   12   |   02   | Ethernet EtherType
+	const (
+		etOff = 12
+		etLen = 2
+
+		etARP = 0x0806
+	)
+
+	// Set up a VM to filter traffic based on if its EtherType
+	// matches the ARP EtherType.
+	vm, err := bpf.NewVM([]bpf.Instruction{
+		// Load EtherType value from Ethernet header
+		bpf.LoadAbsolute{
+			Off:  etOff,
+			Size: etLen,
+		},
+		// If EtherType is equal to the ARP EtherType, jump to allow
+		// packet to be accepted
+		bpf.JumpIf{
+			Cond:     bpf.JumpEqual,
+			Val:      etARP,
+			SkipTrue: 1,
+		},
+		// EtherType does not match the ARP EtherType
+		bpf.RetConstant{
+			Val: 0,
+		},
+		// EtherType matches the ARP EtherType, accept up to 1500
+		// bytes of packet
+		bpf.RetConstant{
+			Val: 1500,
+		},
+	})
+	if err != nil {
+		panic(fmt.Sprintf("failed to load BPF program: %v", err))
+	}
+
+	// Create an Ethernet frame with the ARP EtherType for testing
+	frame := []byte{
+		0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+		0x00, 0x11, 0x22, 0x33, 0x44, 0x55,
+		0x08, 0x06,
+		// Payload omitted for brevity
+	}
+
+	// Run our VM's BPF program using the Ethernet frame as input
+	out, err := vm.Run(frame)
+	if err != nil {
+		panic(fmt.Sprintf("failed to accept Ethernet frame: %v", err))
+	}
+
+	// BPF VM can return a byte count greater than the number of input
+	// bytes, so trim the output to match the input byte length
+	if out > len(frame) {
+		out = len(frame)
+	}
+
+	fmt.Printf("out: %d bytes", out)
+
+	// Output:
+	// out: 14 bytes
+}
+
+// errStr returns the string representation of an error, or
+// "<nil>" if it is nil.
+func errStr(err error) string {
+	if err == nil {
+		return "<nil>"
+	}
+
+	return err.Error()
+}

vendor/golang.org/x/net/icmp/diag_test.go

@@ -0,0 +1,274 @@
+// Copyright 2014 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 icmp_test
+
+import (
+	"errors"
+	"fmt"
+	"net"
+	"os"
+	"runtime"
+	"sync"
+	"testing"
+	"time"
+
+	"golang.org/x/net/icmp"
+	"golang.org/x/net/internal/iana"
+	"golang.org/x/net/internal/nettest"
+	"golang.org/x/net/ipv4"
+	"golang.org/x/net/ipv6"
+)
+
+type diagTest struct {
+	network, address string
+	protocol         int
+	m                icmp.Message
+}
+
+func TestDiag(t *testing.T) {
+	if testing.Short() {
+		t.Skip("avoid external network")
+	}
+
+	t.Run("Ping/NonPrivileged", func(t *testing.T) {
+		switch runtime.GOOS {
+		case "darwin":
+		case "linux":
+			t.Log("you may need to adjust the net.ipv4.ping_group_range kernel state")
+		default:
+			t.Logf("not supported on %s", runtime.GOOS)
+			return
+		}
+		for i, dt := range []diagTest{
+			{
+				"udp4", "0.0.0.0", iana.ProtocolICMP,
+				icmp.Message{
+					Type: ipv4.ICMPTypeEcho, Code: 0,
+					Body: &icmp.Echo{
+						ID:   os.Getpid() & 0xffff,
+						Data: []byte("HELLO-R-U-THERE"),
+					},
+				},
+			},
+
+			{
+				"udp6", "::", iana.ProtocolIPv6ICMP,
+				icmp.Message{
+					Type: ipv6.ICMPTypeEchoRequest, Code: 0,
+					Body: &icmp.Echo{
+						ID:   os.Getpid() & 0xffff,
+						Data: []byte("HELLO-R-U-THERE"),
+					},
+				},
+			},
+		} {
+			if err := doDiag(dt, i); err != nil {
+				t.Error(err)
+			}
+		}
+	})
+	t.Run("Ping/Privileged", func(t *testing.T) {
+		if m, ok := nettest.SupportsRawIPSocket(); !ok {
+			t.Skip(m)
+		}
+		for i, dt := range []diagTest{
+			{
+				"ip4:icmp", "0.0.0.0", iana.ProtocolICMP,
+				icmp.Message{
+					Type: ipv4.ICMPTypeEcho, Code: 0,
+					Body: &icmp.Echo{
+						ID:   os.Getpid() & 0xffff,
+						Data: []byte("HELLO-R-U-THERE"),
+					},
+				},
+			},
+
+			{
+				"ip6:ipv6-icmp", "::", iana.ProtocolIPv6ICMP,
+				icmp.Message{
+					Type: ipv6.ICMPTypeEchoRequest, Code: 0,
+					Body: &icmp.Echo{
+						ID:   os.Getpid() & 0xffff,
+						Data: []byte("HELLO-R-U-THERE"),
+					},
+				},
+			},
+		} {
+			if err := doDiag(dt, i); err != nil {
+				t.Error(err)
+			}
+		}
+	})
+	t.Run("Probe/Privileged", func(t *testing.T) {
+		if m, ok := nettest.SupportsRawIPSocket(); !ok {
+			t.Skip(m)
+		}
+		for i, dt := range []diagTest{
+			{
+				"ip4:icmp", "0.0.0.0", iana.ProtocolICMP,
+				icmp.Message{
+					Type: ipv4.ICMPTypeExtendedEchoRequest, Code: 0,
+					Body: &icmp.ExtendedEchoRequest{
+						ID:    os.Getpid() & 0xffff,
+						Local: true,
+						Extensions: []icmp.Extension{
+							&icmp.InterfaceIdent{
+								Class: 3, Type: 1,
+								Name: "doesnotexist",
+							},
+						},
+					},
+				},
+			},
+
+			{
+				"ip6:ipv6-icmp", "::", iana.ProtocolIPv6ICMP,
+				icmp.Message{
+					Type: ipv6.ICMPTypeExtendedEchoRequest, Code: 0,
+					Body: &icmp.ExtendedEchoRequest{
+						ID:    os.Getpid() & 0xffff,
+						Local: true,
+						Extensions: []icmp.Extension{
+							&icmp.InterfaceIdent{
+								Class: 3, Type: 1,
+								Name: "doesnotexist",
+							},
+						},
+					},
+				},
+			},
+		} {
+			if err := doDiag(dt, i); err != nil {
+				t.Error(err)
+			}
+		}
+	})
+}
+
+func doDiag(dt diagTest, seq int) error {
+	c, err := icmp.ListenPacket(dt.network, dt.address)
+	if err != nil {
+		return err
+	}
+	defer c.Close()
+
+	dst, err := googleAddr(c, dt.protocol)
+	if err != nil {
+		return err
+	}
+
+	if dt.network != "udp6" && dt.protocol == iana.ProtocolIPv6ICMP {
+		var f ipv6.ICMPFilter
+		f.SetAll(true)
+		f.Accept(ipv6.ICMPTypeDestinationUnreachable)
+		f.Accept(ipv6.ICMPTypePacketTooBig)
+		f.Accept(ipv6.ICMPTypeTimeExceeded)
+		f.Accept(ipv6.ICMPTypeParameterProblem)
+		f.Accept(ipv6.ICMPTypeEchoReply)
+		f.Accept(ipv6.ICMPTypeExtendedEchoReply)
+		if err := c.IPv6PacketConn().SetICMPFilter(&f); err != nil {
+			return err
+		}
+	}
+
+	switch m := dt.m.Body.(type) {
+	case *icmp.Echo:
+		m.Seq = 1 << uint(seq)
+	case *icmp.ExtendedEchoRequest:
+		m.Seq = 1 << uint(seq)
+	}
+	wb, err := dt.m.Marshal(nil)
+	if err != nil {
+		return err
+	}
+	if n, err := c.WriteTo(wb, dst); err != nil {
+		return err
+	} else if n != len(wb) {
+		return fmt.Errorf("got %v; want %v", n, len(wb))
+	}
+
+	rb := make([]byte, 1500)
+	if err := c.SetReadDeadline(time.Now().Add(3 * time.Second)); err != nil {
+		return err
+	}
+	n, peer, err := c.ReadFrom(rb)
+	if err != nil {
+		return err
+	}
+	rm, err := icmp.ParseMessage(dt.protocol, rb[:n])
+	if err != nil {
+		return err
+	}
+	switch {
+	case dt.m.Type == ipv4.ICMPTypeEcho && rm.Type == ipv4.ICMPTypeEchoReply:
+		fallthrough
+	case dt.m.Type == ipv6.ICMPTypeEchoRequest && rm.Type == ipv6.ICMPTypeEchoReply:
+		fallthrough
+	case dt.m.Type == ipv4.ICMPTypeExtendedEchoRequest && rm.Type == ipv4.ICMPTypeExtendedEchoReply:
+		fallthrough
+	case dt.m.Type == ipv6.ICMPTypeExtendedEchoRequest && rm.Type == ipv6.ICMPTypeExtendedEchoReply:
+		return nil
+	default:
+		return fmt.Errorf("got %+v from %v; want echo reply or extended echo reply", rm, peer)
+	}
+}
+
+func googleAddr(c *icmp.PacketConn, protocol int) (net.Addr, error) {
+	host := "ipv4.google.com"
+	if protocol == iana.ProtocolIPv6ICMP {
+		host = "ipv6.google.com"
+	}
+	ips, err := net.LookupIP(host)
+	if err != nil {
+		return nil, err
+	}
+	netaddr := func(ip net.IP) (net.Addr, error) {
+		switch c.LocalAddr().(type) {
+		case *net.UDPAddr:
+			return &net.UDPAddr{IP: ip}, nil
+		case *net.IPAddr:
+			return &net.IPAddr{IP: ip}, nil
+		default:
+			return nil, errors.New("neither UDPAddr nor IPAddr")
+		}
+	}
+	if len(ips) > 0 {
+		return netaddr(ips[0])
+	}
+	return nil, errors.New("no A or AAAA record")
+}
+
+func TestConcurrentNonPrivilegedListenPacket(t *testing.T) {
+	if testing.Short() {
+		t.Skip("avoid external network")
+	}
+	switch runtime.GOOS {
+	case "darwin":
+	case "linux":
+		t.Log("you may need to adjust the net.ipv4.ping_group_range kernel state")
+	default:
+		t.Skipf("not supported on %s", runtime.GOOS)
+	}
+
+	network, address := "udp4", "127.0.0.1"
+	if !nettest.SupportsIPv4() {
+		network, address = "udp6", "::1"
+	}
+	const N = 1000
+	var wg sync.WaitGroup
+	wg.Add(N)
+	for i := 0; i < N; i++ {
+		go func() {
+			defer wg.Done()
+			c, err := icmp.ListenPacket(network, address)
+			if err != nil {
+				t.Error(err)
+				return
+			}
+			c.Close()
+		}()
+	}
+	wg.Wait()
+}

vendor/golang.org/x/net/icmp/dstunreach.go

@@ -0,0 +1,41 @@
+// Copyright 2014 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 icmp
+
+// A DstUnreach represents an ICMP destination unreachable message
+// body.
+type DstUnreach struct {
+	Data       []byte      // data, known as original datagram field
+	Extensions []Extension // extensions
+}
+
+// Len implements the Len method of MessageBody interface.
+func (p *DstUnreach) Len(proto int) int {
+	if p == nil {
+		return 0
+	}
+	l, _ := multipartMessageBodyDataLen(proto, true, p.Data, p.Extensions)
+	return 4 + l
+}
+
+// Marshal implements the Marshal method of MessageBody interface.
+func (p *DstUnreach) Marshal(proto int) ([]byte, error) {
+	return marshalMultipartMessageBody(proto, true, p.Data, p.Extensions)
+}
+
+// parseDstUnreach parses b as an ICMP destination unreachable message
+// body.
+func parseDstUnreach(proto int, typ Type, b []byte) (MessageBody, error) {
+	if len(b) < 4 {
+		return nil, errMessageTooShort
+	}
+	p := &DstUnreach{}
+	var err error
+	p.Data, p.Extensions, err = parseMultipartMessageBody(proto, typ, b)
+	if err != nil {
+		return nil, err
+	}
+	return p, nil
+}

vendor/golang.org/x/net/icmp/echo.go

@@ -0,0 +1,157 @@
+// 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 icmp
+
+import "encoding/binary"
+
+// An Echo represents an ICMP echo request or reply message body.
+type Echo struct {
+	ID   int    // identifier
+	Seq  int    // sequence number
+	Data []byte // data
+}
+
+// Len implements the Len method of MessageBody interface.
+func (p *Echo) Len(proto int) int {
+	if p == nil {
+		return 0
+	}
+	return 4 + len(p.Data)
+}
+
+// Marshal implements the Marshal method of MessageBody interface.
+func (p *Echo) Marshal(proto int) ([]byte, error) {
+	b := make([]byte, 4+len(p.Data))
+	binary.BigEndian.PutUint16(b[:2], uint16(p.ID))
+	binary.BigEndian.PutUint16(b[2:4], uint16(p.Seq))
+	copy(b[4:], p.Data)
+	return b, nil
+}
+
+// parseEcho parses b as an ICMP echo request or reply message body.
+func parseEcho(proto int, _ Type, b []byte) (MessageBody, error) {
+	bodyLen := len(b)
+	if bodyLen < 4 {
+		return nil, errMessageTooShort
+	}
+	p := &Echo{ID: int(binary.BigEndian.Uint16(b[:2])), Seq: int(binary.BigEndian.Uint16(b[2:4]))}
+	if bodyLen > 4 {
+		p.Data = make([]byte, bodyLen-4)
+		copy(p.Data, b[4:])
+	}
+	return p, nil
+}
+
+// An ExtendedEchoRequest represents an ICMP extended echo request
+// message body.
+type ExtendedEchoRequest struct {
+	ID         int         // identifier
+	Seq        int         // sequence number
+	Local      bool        // must be true when identifying by name or index
+	Extensions []Extension // extensions
+}
+
+// Len implements the Len method of MessageBody interface.
+func (p *ExtendedEchoRequest) Len(proto int) int {
+	if p == nil {
+		return 0
+	}
+	l, _ := multipartMessageBodyDataLen(proto, false, nil, p.Extensions)
+	return 4 + l
+}
+
+// Marshal implements the Marshal method of MessageBody interface.
+func (p *ExtendedEchoRequest) Marshal(proto int) ([]byte, error) {
+	b, err := marshalMultipartMessageBody(proto, false, nil, p.Extensions)
+	if err != nil {
+		return nil, err
+	}
+	bb := make([]byte, 4)
+	binary.BigEndian.PutUint16(bb[:2], uint16(p.ID))
+	bb[2] = byte(p.Seq)
+	if p.Local {
+		bb[3] |= 0x01
+	}
+	bb = append(bb, b...)
+	return bb, nil
+}
+
+// parseExtendedEchoRequest parses b as an ICMP extended echo request
+// message body.
+func parseExtendedEchoRequest(proto int, typ Type, b []byte) (MessageBody, error) {
+	if len(b) < 4+4 {
+		return nil, errMessageTooShort
+	}
+	p := &ExtendedEchoRequest{ID: int(binary.BigEndian.Uint16(b[:2])), Seq: int(b[2])}
+	if b[3]&0x01 != 0 {
+		p.Local = true
+	}
+	var err error
+	_, p.Extensions, err = parseMultipartMessageBody(proto, typ, b[4:])
+	if err != nil {
+		return nil, err
+	}
+	return p, nil
+}
+
+// An ExtendedEchoReply represents an ICMP extended echo reply message
+// body.
+type ExtendedEchoReply struct {
+	ID     int  // identifier
+	Seq    int  // sequence number
+	State  int  // 3-bit state working together with Message.Code
+	Active bool // probed interface is active
+	IPv4   bool // probed interface runs IPv4
+	IPv6   bool // probed interface runs IPv6
+}
+
+// Len implements the Len method of MessageBody interface.
+func (p *ExtendedEchoReply) Len(proto int) int {
+	if p == nil {
+		return 0
+	}
+	return 4
+}
+
+// Marshal implements the Marshal method of MessageBody interface.
+func (p *ExtendedEchoReply) Marshal(proto int) ([]byte, error) {
+	b := make([]byte, 4)
+	binary.BigEndian.PutUint16(b[:2], uint16(p.ID))
+	b[2] = byte(p.Seq)
+	b[3] = byte(p.State<<5) & 0xe0
+	if p.Active {
+		b[3] |= 0x04
+	}
+	if p.IPv4 {
+		b[3] |= 0x02
+	}
+	if p.IPv6 {
+		b[3] |= 0x01
+	}
+	return b, nil
+}
+
+// parseExtendedEchoReply parses b as an ICMP extended echo reply
+// message body.
+func parseExtendedEchoReply(proto int, _ Type, b []byte) (MessageBody, error) {
+	if len(b) < 4 {
+		return nil, errMessageTooShort
+	}
+	p := &ExtendedEchoReply{
+		ID:    int(binary.BigEndian.Uint16(b[:2])),
+		Seq:   int(b[2]),
+		State: int(b[3]) >> 5,
+	}
+	if b[3]&0x04 != 0 {
+		p.Active = true
+	}
+	if b[3]&0x02 != 0 {
+		p.IPv4 = true
+	}
+	if b[3]&0x01 != 0 {
+		p.IPv6 = true
+	}
+	return p, nil
+}

vendor/golang.org/x/net/icmp/endpoint.go

@@ -0,0 +1,112 @@
+// Copyright 2014 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 icmp
+
+import (
+	"net"
+	"runtime"
+	"time"
+
+	"golang.org/x/net/ipv4"
+	"golang.org/x/net/ipv6"
+)
+
+var _ net.PacketConn = &PacketConn{}
+
+// A PacketConn represents a packet network endpoint that uses either
+// ICMPv4 or ICMPv6.
+type PacketConn struct {
+	c  net.PacketConn
+	p4 *ipv4.PacketConn
+	p6 *ipv6.PacketConn
+}
+
+func (c *PacketConn) ok() bool { return c != nil && c.c != nil }
+
+// IPv4PacketConn returns the ipv4.PacketConn of c.
+// It returns nil when c is not created as the endpoint for ICMPv4.
+func (c *PacketConn) IPv4PacketConn() *ipv4.PacketConn {
+	if !c.ok() {
+		return nil
+	}
+	return c.p4
+}
+
+// IPv6PacketConn returns the ipv6.PacketConn of c.
+// It returns nil when c is not created as the endpoint for ICMPv6.
+func (c *PacketConn) IPv6PacketConn() *ipv6.PacketConn {
+	if !c.ok() {
+		return nil
+	}
+	return c.p6
+}
+
+// ReadFrom reads an ICMP message from the connection.
+func (c *PacketConn) ReadFrom(b []byte) (int, net.Addr, error) {
+	if !c.ok() {
+		return 0, nil, errInvalidConn
+	}
+	// Please be informed that ipv4.NewPacketConn enables
+	// IP_STRIPHDR option by default on Darwin.
+	// See golang.org/issue/9395 for further information.
+	if runtime.GOOS == "darwin" && c.p4 != nil {
+		n, _, peer, err := c.p4.ReadFrom(b)
+		return n, peer, err
+	}
+	return c.c.ReadFrom(b)
+}
+
+// WriteTo writes the ICMP message b to dst.
+// Dst must be net.UDPAddr when c is a non-privileged
+// datagram-oriented ICMP endpoint. Otherwise it must be net.IPAddr.
+func (c *PacketConn) WriteTo(b []byte, dst net.Addr) (int, error) {
+	if !c.ok() {
+		return 0, errInvalidConn
+	}
+	return c.c.WriteTo(b, dst)
+}
+
+// Close closes the endpoint.
+func (c *PacketConn) Close() error {
+	if !c.ok() {
+		return errInvalidConn
+	}
+	return c.c.Close()
+}
+
+// LocalAddr returns the local network address.
+func (c *PacketConn) LocalAddr() net.Addr {
+	if !c.ok() {
+		return nil
+	}
+	return c.c.LocalAddr()
+}
+
+// SetDeadline sets the read and write deadlines associated with the
+// endpoint.
+func (c *PacketConn) SetDeadline(t time.Time) error {
+	if !c.ok() {
+		return errInvalidConn
+	}
+	return c.c.SetDeadline(t)
+}
+
+// SetReadDeadline sets the read deadline associated with the
+// endpoint.
+func (c *PacketConn) SetReadDeadline(t time.Time) error {
+	if !c.ok() {
+		return errInvalidConn
+	}
+	return c.c.SetReadDeadline(t)
+}
+
+// SetWriteDeadline sets the write deadline associated with the
+// endpoint.
+func (c *PacketConn) SetWriteDeadline(t time.Time) error {
+	if !c.ok() {
+		return errInvalidConn
+	}
+	return c.c.SetWriteDeadline(t)
+}

vendor/golang.org/x/net/icmp/example_test.go

@@ -0,0 +1,63 @@
+// Copyright 2014 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 icmp_test
+
+import (
+	"log"
+	"net"
+	"os"
+	"runtime"
+
+	"golang.org/x/net/icmp"
+	"golang.org/x/net/ipv6"
+)
+
+func ExamplePacketConn_nonPrivilegedPing() {
+	switch runtime.GOOS {
+	case "darwin":
+	case "linux":
+		log.Println("you may need to adjust the net.ipv4.ping_group_range kernel state")
+	default:
+		log.Println("not supported on", runtime.GOOS)
+		return
+	}
+
+	c, err := icmp.ListenPacket("udp6", "fe80::1%en0")
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer c.Close()
+
+	wm := icmp.Message{
+		Type: ipv6.ICMPTypeEchoRequest, Code: 0,
+		Body: &icmp.Echo{
+			ID: os.Getpid() & 0xffff, Seq: 1,
+			Data: []byte("HELLO-R-U-THERE"),
+		},
+	}
+	wb, err := wm.Marshal(nil)
+	if err != nil {
+		log.Fatal(err)
+	}
+	if _, err := c.WriteTo(wb, &net.UDPAddr{IP: net.ParseIP("ff02::1"), Zone: "en0"}); err != nil {
+		log.Fatal(err)
+	}
+
+	rb := make([]byte, 1500)
+	n, peer, err := c.ReadFrom(rb)
+	if err != nil {
+		log.Fatal(err)
+	}
+	rm, err := icmp.ParseMessage(58, rb[:n])
+	if err != nil {
+		log.Fatal(err)
+	}
+	switch rm.Type {
+	case ipv6.ICMPTypeEchoReply:
+		log.Printf("got reflection from %v", peer)
+	default:
+		log.Printf("got %+v; want echo reply", rm)
+	}
+}

vendor/golang.org/x/net/icmp/extension.go

@@ -0,0 +1,108 @@
+// Copyright 2015 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 icmp
+
+import (
+	"encoding/binary"
+
+	"golang.org/x/net/ipv4"
+	"golang.org/x/net/ipv6"
+)
+
+// An Extension represents an ICMP extension.
+type Extension interface {
+	// Len returns the length of ICMP extension.
+	// Proto must be either the ICMPv4 or ICMPv6 protocol number.
+	Len(proto int) int
+
+	// Marshal returns the binary encoding of ICMP extension.
+	// Proto must be either the ICMPv4 or ICMPv6 protocol number.
+	Marshal(proto int) ([]byte, error)
+}
+
+const extensionVersion = 2
+
+func validExtensionHeader(b []byte) bool {
+	v := int(b[0]&0xf0) >> 4
+	s := binary.BigEndian.Uint16(b[2:4])
+	if s != 0 {
+		s = checksum(b)
+	}
+	if v != extensionVersion || s != 0 {
+		return false
+	}
+	return true
+}
+
+// parseExtensions parses b as a list of ICMP extensions.
+// The length attribute l must be the length attribute field in
+// received icmp messages.
+//
+// It will return a list of ICMP extensions and an adjusted length
+// attribute that represents the length of the padded original
+// datagram field. Otherwise, it returns an error.
+func parseExtensions(typ Type, b []byte, l int) ([]Extension, int, error) {
+	// Still a lot of non-RFC 4884 compliant implementations are
+	// out there. Set the length attribute l to 128 when it looks
+	// inappropriate for backwards compatibility.
+	//
+	// A minimal extension at least requires 8 octets; 4 octets
+	// for an extension header, and 4 octets for a single object
+	// header.
+	//
+	// See RFC 4884 for further information.
+	switch typ {
+	case ipv4.ICMPTypeExtendedEchoRequest, ipv6.ICMPTypeExtendedEchoRequest:
+		if len(b) < 8 || !validExtensionHeader(b) {
+			return nil, -1, errNoExtension
+		}
+		l = 0
+	default:
+		if 128 > l || l+8 > len(b) {
+			l = 128
+		}
+		if l+8 > len(b) {
+			return nil, -1, errNoExtension
+		}
+		if !validExtensionHeader(b[l:]) {
+			if l == 128 {
+				return nil, -1, errNoExtension
+			}
+			l = 128
+			if !validExtensionHeader(b[l:]) {
+				return nil, -1, errNoExtension
+			}
+		}
+	}
+	var exts []Extension
+	for b = b[l+4:]; len(b) >= 4; {
+		ol := int(binary.BigEndian.Uint16(b[:2]))
+		if 4 > ol || ol > len(b) {
+			break
+		}
+		switch b[2] {
+		case classMPLSLabelStack:
+			ext, err := parseMPLSLabelStack(b[:ol])
+			if err != nil {
+				return nil, -1, err
+			}
+			exts = append(exts, ext)
+		case classInterfaceInfo:
+			ext, err := parseInterfaceInfo(b[:ol])
+			if err != nil {
+				return nil, -1, err
+			}
+			exts = append(exts, ext)
+		case classInterfaceIdent:
+			ext, err := parseInterfaceIdent(b[:ol])
+			if err != nil {
+				return nil, -1, err
+			}
+			exts = append(exts, ext)
+		}
+		b = b[ol:]
+	}
+	return exts, l, nil
+}

vendor/golang.org/x/net/icmp/extension_test.go

@@ -0,0 +1,333 @@
+// Copyright 2015 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 icmp
+
+import (
+	"fmt"
+	"net"
+	"reflect"
+	"testing"
+
+	"golang.org/x/net/internal/iana"
+	"golang.org/x/net/ipv4"
+	"golang.org/x/net/ipv6"
+)
+
+func TestMarshalAndParseExtension(t *testing.T) {
+	fn := func(t *testing.T, proto int, typ Type, hdr, obj []byte, te Extension) error {
+		b, err := te.Marshal(proto)
+		if err != nil {
+			return err
+		}
+		if !reflect.DeepEqual(b, obj) {
+			return fmt.Errorf("got %#v; want %#v", b, obj)
+		}
+		switch typ {
+		case ipv4.ICMPTypeExtendedEchoRequest, ipv6.ICMPTypeExtendedEchoRequest:
+			exts, l, err := parseExtensions(typ, append(hdr, obj...), 0)
+			if err != nil {
+				return err
+			}
+			if l != 0 {
+				return fmt.Errorf("got %d; want 0", l)
+			}
+			if !reflect.DeepEqual(exts, []Extension{te}) {
+				return fmt.Errorf("got %#v; want %#v", exts[0], te)
+			}
+		default:
+			for i, wire := range []struct {
+				data     []byte // original datagram
+				inlattr  int    // length of padded original datagram, a hint
+				outlattr int    // length of padded original datagram, a want
+				err      error
+			}{
+				{nil, 0, -1, errNoExtension},
+				{make([]byte, 127), 128, -1, errNoExtension},
+
+				{make([]byte, 128), 127, -1, errNoExtension},
+				{make([]byte, 128), 128, -1, errNoExtension},
+				{make([]byte, 128), 129, -1, errNoExtension},
+
+				{append(make([]byte, 128), append(hdr, obj...)...), 127, 128, nil},
+				{append(make([]byte, 128), append(hdr, obj...)...), 128, 128, nil},
+				{append(make([]byte, 128), append(hdr, obj...)...), 129, 128, nil},
+
+				{append(make([]byte, 512), append(hdr, obj...)...), 511, -1, errNoExtension},
+				{append(make([]byte, 512), append(hdr, obj...)...), 512, 512, nil},
+				{append(make([]byte, 512), append(hdr, obj...)...), 513, -1, errNoExtension},
+			} {
+				exts, l, err := parseExtensions(typ, wire.data, wire.inlattr)
+				if err != wire.err {
+					return fmt.Errorf("#%d: got %v; want %v", i, err, wire.err)
+				}
+				if wire.err != nil {
+					continue
+				}
+				if l != wire.outlattr {
+					return fmt.Errorf("#%d: got %d; want %d", i, l, wire.outlattr)
+				}
+				if !reflect.DeepEqual(exts, []Extension{te}) {
+					return fmt.Errorf("#%d: got %#v; want %#v", i, exts[0], te)
+				}
+			}
+		}
+		return nil
+	}
+
+	t.Run("MPLSLabelStack", func(t *testing.T) {
+		for _, et := range []struct {
+			proto int
+			typ   Type
+			hdr   []byte
+			obj   []byte
+			ext   Extension
+		}{
+			// MPLS label stack with no label
+			{
+				proto: iana.ProtocolICMP,
+				typ:   ipv4.ICMPTypeDestinationUnreachable,
+				hdr: []byte{
+					0x20, 0x00, 0x00, 0x00,
+				},
+				obj: []byte{
+					0x00, 0x04, 0x01, 0x01,
+				},
+				ext: &MPLSLabelStack{
+					Class: classMPLSLabelStack,
+					Type:  typeIncomingMPLSLabelStack,
+				},
+			},
+			// MPLS label stack with a single label
+			{
+				proto: iana.ProtocolIPv6ICMP,
+				typ:   ipv6.ICMPTypeDestinationUnreachable,
+				hdr: []byte{
+					0x20, 0x00, 0x00, 0x00,
+				},
+				obj: []byte{
+					0x00, 0x08, 0x01, 0x01,
+					0x03, 0xe8, 0xe9, 0xff,
+				},
+				ext: &MPLSLabelStack{
+					Class: classMPLSLabelStack,
+					Type:  typeIncomingMPLSLabelStack,
+					Labels: []MPLSLabel{
+						{
+							Label: 16014,
+							TC:    0x4,
+							S:     true,
+							TTL:   255,
+						},
+					},
+				},
+			},
+			// MPLS label stack with multiple labels
+			{
+				proto: iana.ProtocolICMP,
+				typ:   ipv4.ICMPTypeDestinationUnreachable,
+				hdr: []byte{
+					0x20, 0x00, 0x00, 0x00,
+				},
+				obj: []byte{
+					0x00, 0x0c, 0x01, 0x01,
+					0x03, 0xe8, 0xde, 0xfe,
+					0x03, 0xe8, 0xe1, 0xff,
+				},
+				ext: &MPLSLabelStack{
+					Class: classMPLSLabelStack,
+					Type:  typeIncomingMPLSLabelStack,
+					Labels: []MPLSLabel{
+						{
+							Label: 16013,
+							TC:    0x7,
+							S:     false,
+							TTL:   254,
+						},
+						{
+							Label: 16014,
+							TC:    0,
+							S:     true,
+							TTL:   255,
+						},
+					},
+				},
+			},
+		} {
+			if err := fn(t, et.proto, et.typ, et.hdr, et.obj, et.ext); err != nil {
+				t.Error(err)
+			}
+		}
+	})
+	t.Run("InterfaceInfo", func(t *testing.T) {
+		for _, et := range []struct {
+			proto int
+			typ   Type
+			hdr   []byte
+			obj   []byte
+			ext   Extension
+		}{
+			// Interface information with no attribute
+			{
+				proto: iana.ProtocolICMP,
+				typ:   ipv4.ICMPTypeDestinationUnreachable,
+				hdr: []byte{
+					0x20, 0x00, 0x00, 0x00,
+				},
+				obj: []byte{
+					0x00, 0x04, 0x02, 0x00,
+				},
+				ext: &InterfaceInfo{
+					Class: classInterfaceInfo,
+				},
+			},
+			// Interface information with ifIndex and name
+			{
+				proto: iana.ProtocolICMP,
+				typ:   ipv4.ICMPTypeDestinationUnreachable,
+				hdr: []byte{
+					0x20, 0x00, 0x00, 0x00,
+				},
+				obj: []byte{
+					0x00, 0x10, 0x02, 0x0a,
+					0x00, 0x00, 0x00, 0x10,
+					0x08, byte('e'), byte('n'), byte('1'),
+					byte('0'), byte('1'), 0x00, 0x00,
+				},
+				ext: &InterfaceInfo{
+					Class: classInterfaceInfo,
+					Type:  0x0a,
+					Interface: &net.Interface{
+						Index: 16,
+						Name:  "en101",
+					},
+				},
+			},
+			// Interface information with ifIndex, IPAddr, name and MTU
+			{
+				proto: iana.ProtocolIPv6ICMP,
+				typ:   ipv6.ICMPTypeDestinationUnreachable,
+				hdr: []byte{
+					0x20, 0x00, 0x00, 0x00,
+				},
+				obj: []byte{
+					0x00, 0x28, 0x02, 0x0f,
+					0x00, 0x00, 0x00, 0x0f,
+					0x00, 0x02, 0x00, 0x00,
+					0xfe, 0x80, 0x00, 0x00,
+					0x00, 0x00, 0x00, 0x00,
+					0x00, 0x00, 0x00, 0x00,
+					0x00, 0x00, 0x00, 0x01,
+					0x08, byte('e'), byte('n'), byte('1'),
+					byte('0'), byte('1'), 0x00, 0x00,
+					0x00, 0x00, 0x20, 0x00,
+				},
+				ext: &InterfaceInfo{
+					Class: classInterfaceInfo,
+					Type:  0x0f,
+					Interface: &net.Interface{
+						Index: 15,
+						Name:  "en101",
+						MTU:   8192,
+					},
+					Addr: &net.IPAddr{
+						IP:   net.ParseIP("fe80::1"),
+						Zone: "en101",
+					},
+				},
+			},
+		} {
+			if err := fn(t, et.proto, et.typ, et.hdr, et.obj, et.ext); err != nil {
+				t.Error(err)
+			}
+		}
+	})
+	t.Run("InterfaceIdent", func(t *testing.T) {
+		for _, et := range []struct {
+			proto int
+			typ   Type
+			hdr   []byte
+			obj   []byte
+			ext   Extension
+		}{
+			// Interface identification by name
+			{
+				proto: iana.ProtocolICMP,
+				typ:   ipv4.ICMPTypeExtendedEchoRequest,
+				hdr: []byte{
+					0x20, 0x00, 0x00, 0x00,
+				},
+				obj: []byte{
+					0x00, 0x0c, 0x03, 0x01,
+					byte('e'), byte('n'), byte('1'), byte('0'),
+					byte('1'), 0x00, 0x00, 0x00,
+				},
+				ext: &InterfaceIdent{
+					Class: classInterfaceIdent,
+					Type:  typeInterfaceByName,
+					Name:  "en101",
+				},
+			},
+			// Interface identification by index
+			{
+				proto: iana.ProtocolIPv6ICMP,
+				typ:   ipv6.ICMPTypeExtendedEchoRequest,
+				hdr: []byte{
+					0x20, 0x00, 0x00, 0x00,
+				},
+				obj: []byte{
+					0x00, 0x0c, 0x03, 0x02,
+					0x00, 0x00, 0x00, 0x00,
+					0x00, 0x00, 0x03, 0x8f,
+				},
+				ext: &InterfaceIdent{
+					Class: classInterfaceIdent,
+					Type:  typeInterfaceByIndex,
+					Index: 911,
+				},
+			},
+			// Interface identification by address
+			{
+				proto: iana.ProtocolICMP,
+				typ:   ipv4.ICMPTypeExtendedEchoRequest,
+				hdr: []byte{
+					0x20, 0x00, 0x00, 0x00,
+				},
+				obj: []byte{
+					0x00, 0x10, 0x03, 0x03,
+					byte(iana.AddrFamily48bitMAC >> 8), byte(iana.AddrFamily48bitMAC & 0x0f), 0x06, 0x00,
+					0x01, 0x23, 0x45, 0x67,
+					0x89, 0xab, 0x00, 0x00,
+				},
+				ext: &InterfaceIdent{
+					Class: classInterfaceIdent,
+					Type:  typeInterfaceByAddress,
+					AFI:   iana.AddrFamily48bitMAC,
+					Addr:  []byte{0x01, 0x23, 0x45, 0x67, 0x89, 0xab},
+				},
+			},
+		} {
+			if err := fn(t, et.proto, et.typ, et.hdr, et.obj, et.ext); err != nil {
+				t.Error(err)
+			}
+		}
+	})
+}
+
+func TestParseInterfaceName(t *testing.T) {
+	ifi := InterfaceInfo{Interface: &net.Interface{}}
+	for i, tt := range []struct {
+		b []byte
+		error
+	}{
+		{[]byte{0, 'e', 'n', '0'}, errInvalidExtension},
+		{[]byte{4, 'e', 'n', '0'}, nil},
+		{[]byte{7, 'e', 'n', '0', 0xff, 0xff, 0xff, 0xff}, errInvalidExtension},
+		{[]byte{8, 'e', 'n', '0', 0xff, 0xff, 0xff}, errMessageTooShort},
+	} {
+		if _, err := ifi.parseName(tt.b); err != tt.error {
+			t.Errorf("#%d: got %v; want %v", i, err, tt.error)
+		}
+	}
+}

vendor/golang.org/x/net/icmp/helper_posix.go

@@ -0,0 +1,75 @@
+// Copyright 2014 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 dragonfly freebsd linux netbsd openbsd solaris windows
+
+package icmp
+
+import (
+	"net"
+	"strconv"
+	"syscall"
+)
+
+func sockaddr(family int, address string) (syscall.Sockaddr, error) {
+	switch family {
+	case syscall.AF_INET:
+		a, err := net.ResolveIPAddr("ip4", address)
+		if err != nil {
+			return nil, err
+		}
+		if len(a.IP) == 0 {
+			a.IP = net.IPv4zero
+		}
+		if a.IP = a.IP.To4(); a.IP == nil {
+			return nil, net.InvalidAddrError("non-ipv4 address")
+		}
+		sa := &syscall.SockaddrInet4{}
+		copy(sa.Addr[:], a.IP)
+		return sa, nil
+	case syscall.AF_INET6:
+		a, err := net.ResolveIPAddr("ip6", address)
+		if err != nil {
+			return nil, err
+		}
+		if len(a.IP) == 0 {
+			a.IP = net.IPv6unspecified
+		}
+		if a.IP.Equal(net.IPv4zero) {
+			a.IP = net.IPv6unspecified
+		}
+		if a.IP = a.IP.To16(); a.IP == nil || a.IP.To4() != nil {
+			return nil, net.InvalidAddrError("non-ipv6 address")
+		}
+		sa := &syscall.SockaddrInet6{ZoneId: zoneToUint32(a.Zone)}
+		copy(sa.Addr[:], a.IP)
+		return sa, nil
+	default:
+		return nil, net.InvalidAddrError("unexpected family")
+	}
+}
+
+func zoneToUint32(zone string) uint32 {
+	if zone == "" {
+		return 0
+	}
+	if ifi, err := net.InterfaceByName(zone); err == nil {
+		return uint32(ifi.Index)
+	}
+	n, err := strconv.Atoi(zone)
+	if err != nil {
+		return 0
+	}
+	return uint32(n)
+}
+
+func last(s string, b byte) int {
+	i := len(s)
+	for i--; i >= 0; i-- {
+		if s[i] == b {
+			break
+		}
+	}
+	return i
+}